DE1500165A1 - Method for controlling the actuator of a regulating device, in particular a solenoid valve - Google Patents

Description

Patent attorney Dipi.-Phys. Gerhard Liedl 8 Munich 22 Steinsdorfstr. 21-22 Tel. 29 84

P 15 OO 165.7 B 2701

August 10, 1968

MONSANTO COMPANY, 800 North Lindbergh Boulevard, St. LOUIS, Missouri / USA

Method for controlling the actuator of a regulating device , in particular a solenoid valve

The invention relates to a method for controlling the actuator a control device, in particular a solenoid valve, by means of an excitation current, in which a restoring force is applied to the actuator towards an end position and the magnetic force of the solenoid acts in the direction of the other end position.

N & u underlay

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It is known to control the sequence of chemical production processes to a greater or lesser extent with the aid of electrical cantrollers. Although a large number of electrical control and monitoring elements are known, the last control element, for example a control valve for flow measurement, is often not electrically but pneumatically controlled. Such pneumatically controlled valves, such as an "air motor ¹¹ valve, are advantageous if monitoring devices are used at the same time that generate pneumatic pulses directly. In an electronically controlled and fully automatic chemical production process, however, these aforementioned control devices prove to be inadequate.

Above all, a control device for chemical work processes is important to demand that she respond quickly. However, this requirement can only be met with a pneumatically operated control device be met very imperfectly. Attempts have therefore been made from various sides to use electrical control devices to bring, but still have a number of disadvantages. One of these disadvantages can be seen in the fact that the known electrical control valves are provided with an electric motor,

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which takes the place of the previous air motor and is very expensive. With regard to the response time of such electrical valve devices, too, some wishes remain unfulfilled. Also the reliability must be described as insufficient.

With regard to the limitations faced by the pneumatic control systems are subject to the z. Currently known control devices have the main disadvantage that the breadth of the dynamic range not big enough and the response and reaction time is not short enough. The effectiveness of the known facilities will continue impaired in that the accuracy is insufficient and an undesirable, relatively large hysteresis cannot be avoided.

Attempts to address the inadequacies of the known control devices to overcome by creating suitable other facilities, led to the so-called solenoid valves, in which the movement of the actuator, d. H. the movement of the valve piston, with the help a current-carrying coil is effected, the core of which is wholly or is partially formed by the valve piston. The piston is in such valves by gravity or a spring force, if necessary also through these two forces, in its one end position

²⁷⁰¹ 909821/0454

ma Δ. around

held as long as there is no current flowing through the coil. If a current flows through the coil, a magnetic field builds up, which the piston after overcoming the counterforce or the Brings opposing forces into its second end position. Such solenoid valves, which normally work with direct current, are for example in German Auslegeschrift 1 169 242 and in U.S. Patents 2,570,450 and 3,082,359. Through suitable Measures, for example by means of a short-circuit ring inside the coil, which counteracts rapid field changes, as shown by the valve arrangement according to US Pat. No. 3,082,359, or by using a holding magnet instead of a holding spring, As is the case with the valve according to German Auslegeschrift 1 169 242, alternating current can also be used for the Control of solenoid valves can be used.

All these known solenoid valves have in common the property that the actuator, d. H. the piston, either in its one or in its other end position, and that the permanent one Change from one end position to the other, especially under the effect of uncontrolled axial vibrations, which, however, as the German Auslegeschrift 1 169 $ 42 shows, plastic insert

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lay on the piston or on the valve can be controlled to a certain extent can, severe signs of wear of the valve has the consequence that the accuracy of the control is subject to a relatively large hysteresis suffers and that the dynamic range of the valves is also not large enough.

On the basis of this prior art, it is therefore an object of the invention to propose a method for controlling such a control device, which is improved compared to the previously known method, so that the flow can be controlled and monitored over a wide dynamic range. In this case, should be possible ^and apparatus having an internal negative feedback to achieve an improved stability, in particular a use as a ^lt Kraftausgleich-. Furthermore, uncontrolled axial and radial vibrations of the valve piston are to be eliminated, the "rebound vibrations" of the piston being eliminated in particular by controlling the radial vibrations.

This object is achieved in that on the one hand the maximum value of the time-variable magnetic force is greater than the restoring force and the mean value of the time-variable magnetic force is smaller than the restoring force, or that the minimum value of the

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temporally variable magnetic force smaller than the restoring force and the mean value of the time-varying magnetic force is greater than the restoring force.

Further details and features of the invention are from the following Description of preferred embodiments based on attached drawing.

Show it:

Fig. 1 is a vertical section, partially broken away, of a preferred embodiment of an inventive Solenoid valve;

FIG. 2 shows a partial section along line 2-2 in FIG. 1; FIG.

3 shows a diagram of a control and monitoring device with the solenoid valve according to FIG. 1;

4 shows a diagram of a control and monitoring device with the solenoid valve of Figure 1, which serves as a liquid level regulator;

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5 shows a schematic representation, partially broken away, a further solenoid valve for which the solenoid valve according to FIG. 1 serves as a switching valve;

FIG. 6 shows a diagram of a wave-shaped voltage which is fed to the control device according to FIG. 3 as well as a graphic representation of the control pulse generated in this way;

7 is a diagrammatic representation of the wave-like shape of the magnet winding supplied voltage pulse as a function of time on the resulting magnetic force and the vibratory movement of the valve piston;

8 shows a vertical section, partially broken away, of a further preferred embodiment of a device according to the invention Solenoid valve;

9 shows a partial section along line 9-9 in FIG. 8 according to FIG. 3;

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Fig. 10 is a schematic representation of the solenoid valve according to FIG. 8, which is used as a differential pressure meter and Pulse generator or receiver is used;

11 is a vertical section, partially broken away, of a third preferred embodiment of a solenoid valve according to the invention;

FIG. 12 shows a partial section along line 12-12 in FIG. 11; FIG. 13 shows a partial section along line 13-13 in FIG. 11;

14 is a graph showing "rebound vibration", tension and magnetic force as a function of time for a valve that is not provided with guide rings;

15 shows a diagram similar to that in accordance with FIG. 14, in which the axial vibration, the magnetic force and the voltage in a valve according to the invention as a function of time are shown;

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16 shows a vertical section, partially broken away, another preferred embodiment of a solenoid valve according to the invention;

FIG. 17 shows a section along line 17-17 in FIG. 18; FIG. 18 shows a section along line 18-18 in “Big. 16;

19 shows a horizontal partial section of a special embodiment of a valve piston of the valve according to Fig. 16;

20 shows a vertical section, partially broken away, another preferred embodiment of a solenoid valve according to the invention;

FIG. 21 shows a partial section along line 21-21 to FIG. 20; FIG.

22 shows a vertical section, partially broken away, of a preferred embodiment of an embodiment according to the invention "Rever egg" solenoid valves;

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23 shows a partial section along line 23-23 in FIG. 22;

24 shows a partial section of a preferred embodiment of a valve seat of the valve according to FIG. 22;

25 shows a partial section of a further preferred embodiment a valve seat of the valve according to FIG. 22;

26 shows a diagram of a control and monitoring device with the solenoid valve according to FIG. 22;

Figs. 27, 28, 29, 30 and 31

electrical waveforms to illustrate the operation of the control device according to FIG
Fig. 26, where

Fig. 27 shows a full wave of rectified voltage represents that is applied to a silicone-controlled rectifier,

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28 shows a half-wave of a rectified

Represents voltage that is applied to a controlled rectifier and together is used with a resistive charge,

Figure 29 illustrates the waveform of the electric current supplied to a controlled rectifier the control device is not provided with a diode 363,

Fig. 30 shows the waveform of the control current,

which is fed to the controlled rectifier in the control device according to FIG. 26 when the diode 363 of the solenoid of the control valve is connected in parallel,

31 shows the current which, in the steady state of equilibrium, of the solenoid winding of the valve is supplied according to FIG. 22;

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32 shows a diagram of the flow rate through a valve according to FIG. 1 as a function of the "ignition" angle and the control resistance of the control device according to FIG. 3;

Fig. 33 is a map showing the liquid control characteristics the valve of Figure 1 and the flow rate are shown as a function of the liquid level;

FIG. 34 is a diagram of the flow characteristics of the "reversing ^u solenoid valve according to - FIG. 22 with constant inlet pressure.

general description

With an electrically controllable valve according to the invention, the control takes place in that the voltages which are fed to the windings of a magnetic coil are changed. A valve according to the invention permits. the control of the flow of a flow medium as a function of a variable, physical measured variable.

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Such a measured variable can be ζ, B, a liquid level. One The device according to the invention therefore has very wide application possibilities, for example as a liquid level regulator, differential pressure regulator, Temperature controller, etc. A valve according to the invention is provided with an inlet and an outlet, the outlet has a valve seat. A piston is slidable with respect to the valve seat, thereby controlling the flow of liquid takes place through the valve housing. The piston is made of metal and can be actuated by a magnetic coil winding around it will.

The control takes place according to a new control principle using the vibrations and oscillations of the piston with a certain periodicity. The mechanical vibrations of the piston are generated by the action of the force of the magnetic coil. During a cycle, the force acting on the piston first increases from a certain level, reaches a maximum and then returns to the initial level. If the resulting average force is equal to or greater than the spring force, the piston is held in a certain position. However, if the average force exerted on the piston is less than the spring force, will

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the piston is lifted from the aforementioned first position during a certain short period of the cycle when the maximum force during the cycle is greater than the spring force. When the piston has lifted, its movement can be represented by the usual differential equations to be discribed. The opening of the valve can be done very well by the integral for the time between the two end positions of the piston are described,

After the foregoing more or less general description of the invention, the individual details and Embodiments described. With A in Figures 1 and 2 of the drawing, a preferred embodiment of an inventive magnetic control valve called. The cooperation of valve A with an electrical control circuit is shown in the diagram shown in FIG. 3 of the drawing. The control valve A and the control circuit C according to FIG. 3 are first described below described in the drawing.

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- IS -

Control valve

The control valve A is provided with an outer valve housing 1 which encloses an approximately cylindrical coil housing 2. Inside the housing 2 there is a cylindrical solenoid 3 which is provided at its upper and lower ends with insulating rings 4 and 5, respectively. The insulating ring 5 is arranged on the surface of a plate 6 which forms part of the outer coil housing 2. On the upper insulating plate 4 a circular "flux" plate 7 is arranged The arrangement that from the magnet coil 3 _$ the two insulating rings 4 and! 5 and consists of the "river" plate ¹ F, is pressed down with the help of leaf springs 8. The leaf springs 8 are arranged between the "flux" plate 7 and the upper boundary surface of the coil housing 2.

The coil housing 2 and the solenoid 3 are with a central Provided opening which serves to receive a piston cylinder arrangement 9, which is a cylindrical tube 10 with a central, non-magnetic Has portion which is surrounded at both ends by two magnetic sections. At the top of the tube 10 is a bolt 11 fastened with the aid of a nut 12. The bolt 11 extends

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extends inwardly into the tube 10 and has a lower section 13 with a reduced diameter, on which a compression spring 15 is arranged is. A projection 16 adjoins the section 13, whose lower surface 17 serves as a stop for a piston 18, the fin the tube 10 is movably mounted and with four axial recesses 19 is provided. The piston 18 is screwed in at its upper end, whereby the "head" 19 of the piston is formed.

A valve body 20, which is provided with an inlet opening 21 and an outlet opening 22, is screwed to the lower end of the base plate 6. In the valve body 20, a channel 23 is provided which is in communication with a liquid chamber 24. This connection is formed by an opening 25 which is arranged in an upwardly projecting eye 26. The liquid chamber 24 communicates with the outlet 22 via an axial channel 27, which in turn is connected to the axial channel 23. The inlet 21 communicates with the chamber 24 via a further axial channel 27 ′ and the valve chamber 20. The upwardly projecting eye 26 is provided with a flat head which serves as a valve seat β.

In the valve piston 18 a bore is provided, which a Teflon corrosion Disk 28 receives, which is supported by a ring 29 made of FeoFsionebeständigem

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Steel is surrounded. With regard to secondary or "rebound vibrations" of the piston 18, polytetrafluoroethylene or copolymers of tetrafluoroethylene and hexafluoropropylene are recommended as the material. Such secondary vibrations are undesirable because they impair the stability of the valve. Moreover, that will Noise that arises when the valve is in operation, for the most part generated by such secondary vibrations. It was determined, that polytetrafluoroethylene is superior to all other materials as a material. Polytetrafluoroethylene has a high Coefficient of elasticity and allows stable operation. Rebound vibrations are made to disappear sufficiently and the valve seat s has a remarkably enlarged Lifetime on. Full details and details regarding the merits and advantages of polytetrafluoroethylene compared to others Materials are listed below.

Improved stability can also be achieved in that uncontrollable, repeated radial vibrations of the piston 18 can be avoided. This can be achieved, for example, by that the upper part of the piston with a polytetrafluoroethylene tape is wrapped. Preferably, a projection, not shown, is soldered to the valve body with silver so that the The projection engages in one of the recesses 19 of the piston 18.

These recesses are marked in such a way that

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that the piston 18 can always be mounted in the same position and position. This avoids disadvantageous effects which can be attributed to a slight eccentricity of the piston 18 in the opening 25 and constant conditions in the valve seat s are always achieved.

The valve A is provided with an insert 30 which has two inlets 31 for the solenoid 3 receives. The connection of the feed 31 can be seen from FIG. 3 of the drawing and is described in more detail below.

Control circuit C

The control circuit C shown schematically in Fig. 3 of the drawing is provided with a 120 volt AC voltage source, not shown. The voltage is supplied to the magnetic coil 3 via a line 36 with a fuse 37. A neutral conductor 38 is connected to a cathode 39 of a safety-controlled rectifier 40 which is provided with an anode 41 and a grid 42. The anode 41 of the rectifier 40 is connected to the opposite terminal of the magnet coil 3 via a thermistor 43. A fixed resistor 44 is attached to the thermistor 43 to eliminate undesirable

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th temperature influences connected in parallel. The firing angle of the output voltage of the circuit C to the magnetic coil 3 is controlled in that the changes in a physical measured variable are measured, which is shown schematically in Fig. 3 of the drawing by a variable resistor 45, the so-called control resistor.

To control the aforementioned ignition angle as a function of the measured Changes in the physical measured variable are used by a transistor 46, which is used as a relaxation oscillator. The transistor 46 is provided with a 1-base 47, a 2-base 48 and an emitter 49. The emitter 49 can be connected directly to the variable resistor 45 and is in connection with a capacitor 52, which in turn is connected to the neutral conductor 38. The 2 base 48 of the Transistor 46 is connected to a temperature compensating resistor with a limiting resistor 54 and the opposite terminal of the variable resistor 45 in connection. The 1-base of transistor 46 is connected to grid electrode 42 of the controlled rectifier 40 and connected to a fixed resistor 55, which in turn is connected to the neutral conductor 38. The limiting resistor 54 is also connected to the cathode of a diode 56 and to line 36. An arrester 57 is between the two lines

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36 and 38 switched on and is used to derive compensation voltages. A Zener diode 58 is connected between one connection of the resistor 53 and the neutral conductor 38.

Operation of the control circuit C

adjustable
The ... resistance 45 should, as already explained above, the

represent physical variables to be measured. As a result the resistor 45 can be replaced by any pulse generator which is suitable for the changes in a physical measured variable to transform into changes in resistance. Such a pulse generator can be used, for example, to control and register the changes in a liquid level as well as any temperature changes «, For example, when controlling a liquid level

is desired, the device according to Fig. 3 of the drawing,

Ignition according to Fig. 4, can be modified. The angle of the output voltage of the Magnetic coil 3 is then controlled by changes in this physical measured variable. So much for a change in any physical measurable variable converted into a change in an electrical measured variable, for example a voltage, a current or a resistance this change can be symbolized physically by the variable resistor 45.

90982 1

The transistor 46, which serves as a relaxation oscillator, supplies to one controllable time a current pulse to the grid of the controlled rectifier 40 within the positive cycle of the input voltage electric power source. This current pulse is fed to the grid 42 of the rectifier 40 from the 1-base 47 of the transistor 46. When the rectifier 40 receives this signal, it begins to conduct until the direction of the current is reversed, the current flowing through the normal diode action is stopped. So nothing happens during the negative cycle. The operation of the relaxation oscillator is based on the special! Operation of transistor 46, after which a conduction between the emitter 49 and the 1-Ba.; is 47 prevented if the emitter-to-1-base voltage is not greater than a critical value that passes through the base-2 voltage to the base-1 voltage is determined. If this voltage spike is exceeded, If the effective resistance between the emitter 49 and the 1-base falls to a zero value, conduction takes place until the emitter goes to the 1-base voltage falls below the minimum voltage, the so-called till point.

The diode 56 serves as a half-wave rectifier and supplies the control voltage door transistor 4Π, IHu control voltage of the one-way DC

¹ JO) -J · ^; M. ', F, 4

judge 56 is through the limiting resistor 54 and the Zener diode 58 limited, whereby a Recliteekspanmmg is generated. the thus through the diode 56, the resistor 54 and the Zener diode 58 The generated RecMeck voltage is transmitted to the emitter 19 and the 2-base 48 fed through the temperature compensating resistor 53, Dei Capacitor 52, together with variable resistor 45, determines the ignition time of transistor 46. A synchronization with the alternating current lead is achieved by the fact that as the 2-base the same hechteck tension is applied. The capacitor 52 is initial reloaded and is then gradually by one over the resistance incoming current charged. The lower the value of the resistance 45, the faster the charge and the voltage rise at the emitter 49 of the transistor 46 «. During the time of Voltage rise at emitter 49 is the voltage difference between the 1-base and the 2-base constant. When the voltage on the emitter reaches its critical value, the transistor 46 ignites and discharges the capacitor 52 via the resistor 55, so there is electrode 42 of the rectifier 40 current can flow. As a result, the rectifier 40 ignites and supplies the magnetic coil 3 with current. If the changeable Resistance is greater than the critical value, the capacitor becomes not charged to ignition voltage at the end of a positive cycle.

, BAD ORiQIMAL

Although by this type of synchronization the transistor 46 to the Ignition is brought about, only a small one occurs under these conditions Tension along the "load". When the variable resistance is below the critical value, the transistor 46 ignites earlier and that noticeably before the end of the half cycle, with the controlled rectifier conducting for increasing ignition angles. After completion of the ignition process of transistor 46, capacitor 52 is immediately charged again, so that transistor 46 when the resistance is low enough can ignite again before the end of the half cycle. This extra pulse generated by the firing of transistor 46 has no adverse effect, however, since the rectifier is already conducting.

In Fig. 6 of the drawing is the deformation of a sinusoidal, through the AC voltage source generated voltage into the waveform supplied by the controlled rectifier of the solenoid 3, shown. It turns out that the basic output voltage of the control device is a half sine wave after a one-way rectification. The waveform has a positive ignition angle and an "overshoot" part that is in the negative voltage range. Due to the Inductance of the solenoid 3 there is a minimum ignition angle, if the value falls below this, the rectifier 40 is not in the conductive state

remain,

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.-84 -

when firing pulses are fed to it from transistor 46. this will; caused by the fact that, due to the inductance of the magnetic coil 3, a current flow builds up only slowly. If at the end of the

Ignition pulse, the current has not yet built up so far that

Haiteer is greater than the / etrom of rectifier 40, the line will

completed. However, this does not cause any difficulties, since the minimum The ignition angle is below the value at which the vibrations and oscillations begin.

After the rectifier 40 has been ignited, current begins to flow into the magnetic coil 3 flow, the magnetic flux of which exerts a magnetic force on the piston 18. Through the "growth of the magnetic Flux creates an electromotive force that controls the flow of current in the solenoid 3 counteracts. When the flow increases, the force acting on the piston 18 grows until it is with the force of the spring holding the piston comes into balance. When this equilibrium is reached, the piston 18 moves so that the air gap between the surface 17 and the head 19 'is reduced will. In this case, the flux surrounding the magnetic coil 3 continues to be increased.

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If the solenoid 3 were supplied with a constant voltage, so this would have the consequence that the piston 18 would lie against the surface 17. However, the tension gradually decreases, from the moment when the line begins, the ignition angles being less than 90 °. Before the piston 18, the surface or the stop 17 has reached, the tensile force of the solenoid 3 is therefore essential has become lower and under certain circumstances even to a zero value level dropped when the rectifier 40 no longer conducts. By changing the ignition angle of the rectifier 40, the maximum force and the effective pulse width corresponding to the desired changes in the effective valve opening ;. be changed.

"Plant-Scale" control valve

A so-called "plant-scale" control valve P, i. H. a control valve A combination of control valve A and control circuit C can be very advantageous for operating and production systems will. The valve P is provided with a valve housing 70 and liquid passage openings 71 and 72 which are communicated with an inner liquid chamber 73. The supply and discharge

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the liquid takes place via connections 74 and 75, respectively. The valve housing has an upstanding, hollow portion 76 which is tubular is and is used to accommodate a valve piston 77. The valve piston 77 is with the aid of a compression spring 79 against one of the inlet opening 71 formed seat 78 is pressed. The compression spring 79 is between the piston surface and the upper boundary surface of the tube 76 arranged. An O-ring 80 made of polytetrafluoroethylene is used for sealing. The piston 77 has a portion 81 of larger diameter at its lower end. The lower end of the piston 77 is tapered formed so that the surface of an upper, described below Chamber, is substantially equal to the area of the main valve seat. Due to this fact, pressure changes can occur downstream do not affect the position of the main valve.

A pipe 83 is arranged between the inlet and outlet openings, which is provided with a fixed opening 84 and a tube 85 communicating with a chamber 86 leading from the head of the piston 77 and the wall of the tube 76 is formed. In the pipe 83, the valve A and the control circuit C are switched on downstream, which serve as switching or control valve V. The one used to regulate

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Flow is passed through the fixed orifice 84, the pressure, which prevails between the opening 84 and the valve V, on the chamber 86 of the valve P acts. The shaft of the piston 77 is - isolated from the main flow - exposed to this pressure due to the sliding ring 80.

The operation of the valve P is based on an analysis of the movement in a certain open position, the so-called "open loop" position, explained in more detail, since in this case the valve P no feedback signal is forwarded. In this analysis it is assumed that the valve P is a so-called "let-down" valve. In such a "let-down" valve, the pressure upstream must be kept constant. The downstream pressure is also constant, but lower than the upstream pressure. It is now assumed that the pressure upstream controls the flow through the main valve P. determined as a function of the flow through the valve V. Furthermore, it is assumed for the purpose of illustration that the surface of the upper Chamber, d. H. the area of the chamber 86 is equal to the cross-section of the seat 78.

Under this assumption, pressure changes do not affect downstream the location of the main valve piston 77.

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When the valve V is closed, the spring 79 holds the valve piston in the closing position, since there is no differential pressure acting on it. When there is flow through valve V as a result of changes in a physical measured variable, a pressure drop across orifice 84 causes a lower pressure in upper chamber 86 to exist. This differential pressure results in an upward force acting on piston 77. When this upward force is equal to that of the spring 79, the piston 77 begins to lift from its seat 78 so that fluid flow through the main valve P takes place. If the flow through the valve V _r increases further in response to the changes in the physical measured variable -hä & j, the spring force, which is also increased by the lifting of the piston, balances the differential pressure in each case. Accordingly, the amount of piston 77 lift is proportional to the flow rate through valve V minus the flow rate at which main flow through valve P begins. The valve V thus serves as a hydraulic booster and is at the same time designed as a safety device, since the piston 77 returns to its shut-off position if the voltage supply for the valve V fails. If it is desired to open the valve P in the event of a voltage failure, it is only necessary to swap the position of the opening 84 and the valve V.

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During normal operation, the valve V receives a signal that the average opening determined. The flow rate is determined by the pressure drop across valve P. This pressure drop results from the pressure differentials between the downstream and upstream pressures. The flow through valve V is also controlled by the pressure resistances the opening 84 and the valve V is determined. As the flow through valve V increases, the one that has also increased decreases Main flow through valve P the pressure drop across valve V, which causes a reduction in the main flow through valve P. In this way, a completely sufficient stability of the entire system is achieved without an upper limit for the flow through the main valve P is set.

The control system shown in Fig. 5 is very versatile. It can be used, for example, to regulate the position of the main valve piston which is not determined by the interaction between the flow through the main valve P and the flow through the valve V. This is achieved by modulating the valve V in the sense of a flow control for this valve by means of a differential pressure feedback control loop. Changes in the position of the main valve piston are brought about by changes in the target differential pressure.

This is desirable when a certain

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Differential pressure across the valve P is to be maintained. Besides can control the position of the Ventües by measuring the position of the Hauptventües P and with a return branch to Control of the valve P can be achieved. An iron bar can be attached to the main valve, which partially enters the coil, which surrounds the non-magnetic part of the housing of the upper chamber.

A change in the position of the valve therefore produces a change in the inductance of the coil, which is used as a control signal for the valve P can be. This type of control is more advantageous. than the flow measurement when it comes to compressible flows, where the volume of the upper chamber causes a delay.

Such a control device actuated with the valve V has the advantage over the usual air-actuated control valves that a large number of lines can be dispensed with. Another advantage can be seen in the fact that such a control device is very
reacts quickly, and has significantly lower operating costs than any other previously known device, The necessity
a stuffing box, which causes a very negative hysteresis,

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- 31 -

also falls. The so-called "plant-scale" valve can thus be used for a variety of applications can be used, as well as the electrically operated control valve V used in the "plant-scale" valve P is used. Such applications are z. B. the control of a liquid level, a diffusion pressure or a temperature. Feedback control circuits are a preferred area of application.

Liquid level control device

The electrical control circuit C according to FIG. 3 has been modified according to FIG. 4, in order to be able to use valve A for level control. Such a modification with regard to the usability as a level controller however, it is only one of the many possible uses of this electrically operated control device which continues, for. B. can be modified to the effect that they are used to control absolute Pressures, differential pressures as well as temperature control can be used. In a modification of the control circuit C for a flow control it is only necessary to use a differential pressure gauge with a suitable pulse generator. For pressure control it is z. B. only necessary to provide the variable resistor 45 with a corresponding pressure transducer, so that corresponding resistance

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1500155

Stand changes are generated. It is only for temperature control necessary to replace the variable resistor 45 with a suitable temperature-dependent resistor that acts as a receiver serves. The controller can be modified so that it can be used to control a liquid level. Here the variable resistor 45 is replaced by a converter 90 based on a cadmium sulfide resistor, which together with a light source 91 for recording the liquid level changes within a tube 92 is used. It is desirable however, it is not necessary to use a constant voltage transformer (not shown) as the electrical voltage source. One terminal of the cadmium sulfide converter 90 is connected to a "proportional band" potentiometer 93 which has a Fixed resistor 94 is connected to one terminal of converter 90 and to resistor 54, as can be seen in FIG. 4 of the drawing is. This latter connection of the converter 90 is also connected to the sliding connection of a potentiometer 95, the is connected to a further potentiometer 96. The sliding connection is also connected to the emitter 49 and the capacitor 52.

The absorption and "reception" of the fluid level changes will carried out with the help of a very sensitive photocell. As a photo

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cell is a cadmium sulfide photocell, the resistance of which is

directed

gender light intensity decreases. A source with collimated / light is aligned perpendicular to the axis of the pipe, but to the side of the pipe axis. The liquid in the pipe has a larger one Refractive index as vapor, which is why the light beam is broken away laterally when it hits liquid. The cadmium sulfide recipient is set up on the side so that its diaphragm only receives light when it hits the liquid and not the vapor. Because of the fact that such a device responds to the differences in the refractive index does not matter whether one clear or colored liquid is present.

The resistor 94 and the potentiometer 93 are connected in parallel to the converter 90 and serve as proportional band regulators. The potentiometer 95 is used for coarse adjustment and potentiometer 96 for fine adjustment. It shows that one as described above Control device has good stability and is very versatile. It can thus - as described above - a Achieve proportional level control with a proportional band up to 12.5 mm.

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Pressure regulator

The control valve A can still be modified so that it is used for Control and regulation of pressures is suitable. The cadmium sulfide photocell is used for this connected to a pressure source, not shown, which is provided with a conventional pressure graduation. One The pressure gauge plate can be provided with an opening that is aligned with the photocell. A light source is then aligned with the Photocell arranged in this opening. A control flag is attached to a needle on the pressure gauge. This control flag can be moved in the direction of the closed position or in the opposite direction across the opening. When the measured pressure increases, the measuring needle of the valve is moved, which is a shift the control flag. If the control flag is moved over the opening in the direction of the closed position, reduced the incidence of light in the photocell. This also reduces the current supplied to the relaxation oscillator. That the The signal taken from the converter is therefore related to the movement of the control flag and the pressure fluctuations.

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15Q0165

-"8th

as

"Equilibrium of forces device "

The use of the control valve A as a so-called force equilibrium device is shown in Figures 8 to 10 of the drawing. The control valve A is equipped with a control circuit C according to FIG. tied together.

A flue pipe 59 is screwed to a compensation opening 22, which is provided with a constriction 60 with a certain cross section. The line 59 can be connected to a low pressure source stand ,, Due to the fact that the port 60 with respect to the valve Aj is located downstream, there will be an increase in stability is achieved using feedback or so-called "negative" feedback.

It is known that with the help of a positive feedback, the dynamic Can increase the area, but this reduces the stability, especially in electrical control circuits such. B. at directly coupled amplifiers. With the help of a negative feedback, the dynamic range decreased. However, the status

9-09821 / 0454-

Increase bility and reduce noise and distortion. With the help of the constriction 60, the desired negative feedback can be achieved, which leads to an increase in the stability of the control valve contributes.

The aforementioned issue is made through an analysis of the working method illustrated at low flow rates. At low flow rates, the vibration of the valve piston is very low and the Flow takes place near the take-off point. In other words, the piston only lifts from its closed position when when the maximum magnetic force outweighs the downward force acting on the piston. As already stated above, This downward force is composed of the weight of the piston and the spring force. .When the maximum magnetic Force is equal to this resulting force, the valve spool of

lifted from his seat. Due to the differential pressure at the valve

where therefore tilsitz determines the point w "tm the flow at a

given maximum magnetic force begins.

One of the forces that determine the start of vibrations is that Force caused by a differential pressure on the valve seat

90982.1 / 0454

will. As the valve seat area increases, or as the pressure differential increases, the resulting force will also increase in proportion to the other forces acting on the valve. If the device is only used for flow control, this fact is very disadvantageous. This fact can, however, also serve to the advantage in that a stabilization of the flow rate and a linearization of the flow curve over the control voltage is achieved. If the seat surface is made as large as possible in order to achieve the greatest possible differential pressure force, improved conditions are achieved with respect to the flow of the valve when opening if it is used in the "flow-to-open ⁿ -form. Under these conditions, ie with a flow near the beginning of the vibration and with a constant curve shape of the voltage for the solenoid coil, a constant pressure difference arises. The flow thus begins at the critical value of the maximum magnetic force. Below this value there is no flow through the valve Sudden response of the valve can be regulated by controlling the electrical current supplied to the solenoid.

Since the inlet opening is dimensioned so that a flow is immediate arises below the valve seat, since it is a so-called "flow-to-open" form of the valve, causes

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1500115 - · »« ►- 3 *

the pressure upstream that the valve piston is lifted from its seat will.

However, this is compensated for by the downward pressure exerted by the spring 15 and the mass of the piston 18. When the maximum magnetic force and the upward force due to the upstream pressure the downward force, which acts on the piston predominate when it is lifted from its seat. It is to be observed, however, that the area surrounding the piston Liquid causes the piston to move into the closed position. An increased flow through the valve causes a larger one Pressure upstream of the constriction 60 within the line 59. This increased pressure also prevails in the chamber 24 and brings about the valve piston 18 in its closed position. This has a constant balance of forces between the chamber 24 and the inlet 21 As a result, this "internal recirculation" reduces the differential pressures across the valve with a view to increasing the flow rate. The flow rate is thus reduced, which results in improved stability.

Apart from the fact that through internal regression or so-called negative feedback creates increased stability

909821/0454

is, this also has the consequence that the valve A. as a pneumatic Resistance transducers with linear characteristics can be used. The transistor control circuit C is used to generate a Current specific waveform for valves, so that a control or control resistor a linear change in pressure downstream made possible by the valve. The flow rate is therefore linear Function of the control resistor and not an exponential function as usual.

A digital pneumatic converter as described above is very advantageous if the last control element is pneumatically operated in a control device. With the help of such a converter an input resistance signal is converted into a linear-proportional, converted to pneumatic output pressure.

In the known electro-pneumatic converters, a direct current signal is used usually taken from a control circuit in which the coil is moved relative to a permanent magnet * As a result usually a piston rod that is the size of a Opening or a nozzle regulates. A relay-diaphragm arrangement is then switched on, with the purpose of supplying pressure

2701

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an internal valve is opened. The print medium, e.g. B. air, flows into a central chamber of the relay, with the output pressure increases until the relay-diaphragm arrangement is returned to its starting position and the inner valve closes again. Of the The amplified output of the relay is applied to a control valve and connected to a feedback diaphragm. The force of the pressure on this The diaphragm acts on the piston rod. In this way, with the equilibrium of forces condition, the relay output pressure becomes compared with the input signal. When the two forces are in equilibrium, the relay output pressure is directly proportional the input current. By moving a coil as a function of control pulses, a piston rod is thus with respect to a The nozzle is moved, which controls a diaphragm.

Such an electromagnetic converter is very precise Adjustment of the position of all individual parts required. A device according to the invention is therefore the aforementioned, known Control devices are superior because such accuracy is not required and the pneumatic output is linear to the Input impulse behaves.

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150Q155

Due to the fact that the "balance of forces device" A j is provided with an internal return, it works in one very wide operating range completely stable. There are also various possible uses for external feedback: Control of a liquid level, control of pressures, especially absolute pressures, etc.

As a further application example, the application of a "Force equilibrium device" according to the invention described as a differential pressure receiver according to FIG. 10 of the drawing. The control device, which consists of the actual valve A and an electrical control circuit, for example from the control circuit C, is one Power 100 connected in parallel, which is provided with a constriction 101, whereby a high-pressure part 102 and a low-pressure part 103 are formed.

Parallel branch

stand. The valve A is arranged in a 104 which connects the two parts 102 and 103 to one another. A changeable magnetic one

resistance

d or a vibration receiver 105 is with a magnetic coil tied together. The output of the solenoid is to an electrical evaluation device 106 connected.

Around the force equilibrium device "A" as a differential pressure receiver it is necessary to use the electric current in direct

909821

measure weight. A current spike would result in a change in pressure. The electrical evaluation device 106 can be provided with an absolute scale so that the values of the pressure are directly are output in absolute size depending on the current peaks in the solenoid. If a measurement of the pressure change is desired it is necessary to start the vibration of the valve -

piston to determine. This is done with the help of the changeable magnetic

Resistance

& t 105. It is still possible to have a flow meter in the

Parallel branch
ss 104 to determine the beginning of the flow.

This device indicates when the valve is in equilibrium and when the flow or vibration begins.

If after that due to pressure changes between sections

In parallel branches 102 and 103, the flow conditions in 104 change, the pressure along the valve opening will either decrease or increase. This results in a change in the amplitude of the Vibrations of the valve piston, thereby reducing the electrical output values change the solenoid. These electrical output values are then fed to the evaluation device 106. It is thus possible with the aid of the control device A described above, pressure changes to measure over the section 101 in the pipeline 100.

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«3

Valve with flexible piston rings

In Figures 11 to 15 in? the drawing is an electrical control device A shown in Figures 1 and 2 of the drawing, which is provided with one or more flexible rings that surround the valve piston.

The control valve A works with the control device C according to FIG the drawing together. The piston 18 is provided in the vicinity of its two ends with annular grooves for receiving flexible 0-rings 131 and 132 are used. The O-ring 131 has a sufficient one Widen and lies against the inner wall 10 * of the tube 10 and is held in this position by frictional engagement. The same applies to the O-ring 132, which is also frictionally engaged with the inner wall of the valve body 20 is in communication. Bend as the piston 18 moves between its upper and lower positions the 0-rings, but without changing their relative position. The axial movements of the piston 8 are not greater than 0.12 mm maximum vibration. As already mentioned, the O-rings 131, 132 are dimensioned so that they move during the axial movements of the Bend the piston and its position in relation to the rest of the valve A does not change.

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The thickness of the rings 131 and 132 is about 1.75 mm, so that a sufficient flexibility to accommodate the piston movement is guaranteed.

The material used for rings 131 and 132 has been mixed polymer of butadiene and acrylonitrile and synthetic rubber made from fluoroelastomers or linear copolymer made from hexafluoropropylene and vinylidene fluoride proven very well. Such materials have sufficient flexibility so that they can withstand the axial forces without losing their position to change in the piston-cylinder arrangement when the piston 18 moved axially with respect to the arrangement 9.

The valve piston 18 is provided with an axial opening 133 which communicates with radial openings 134 at both ends thereof so that communication between the upper and lower ends of the Chamber 24 is made. The liquid can thus from the lower end of the chamber 24 through the radial opening 134 and the axial opening 133 flow into the upper part of the chamber 24. In this way, the liquid in the chamber 24 does not add any additional liquid Pressure force generated, which is added to the non-equal forces along the valve piston 18.

909821/0454

Without the flexible O-rings 131 and 132 e, the piston Γ8 has two stable vibration positions for each "force level" of the Solenoid 3 on.

With these two vibration positions there is a transition from one in the other position, which takes place within a time of about 16 msec, a "flow constriction" of about 5% can be observed. When the flexible O-rings are used, there is only a vibration position and the flow noise becomes significant reduced. It is therefore believed that this fact affects the maintenance of the radial alignment and guidance of the Piston 18 is to be returned in the arrangement 9. The flexible O-rings 131 and 132 thus contribute to a damping of the uncontrolled, radial Vibration at.

It has also been shown that "rebound vibrations" of the valve piston tend to limit the maximum achievable flow and thus the dynamic range of the control valve. You can In view of the frequency of 60 Hz, a long service life of the valve seat can be achieved, which is due to the low, out of balance is due to the forces of the piston in which the ma

909821/0454

ximal "seat pressure" remains within the elastic range. It leaves but not entirely avoid '' 'that axial "rebound vibrations

■ i
functions "of the piston and uncontrolled, radial vibrations wear and tear

he phenomena arise on the valve seat, causing deformations of the Polytetrafluoroethylene

-Materials occur. However, it has been shown that the invention used flexible O-rings 131 and 132 such uncontrolled, Eliminate axial "rebound vibrations" of the piston and uncontrolled radial vibrations.

It has also been found that the energy normally consumed by high amplitudes and relatively slow vertical rebound vibrations of the piston is absorbed by the flexible O-rings 131 and 132 in a device according to the invention. The "rebound vibrations" of the piston 18, which normally occur, are thus substantially reduced and dampened. As can be seen from FIG. 14 of the drawing, the vibrations of the valve piston of valve A according to the first-mentioned embodiment are still quite considerable. 14 shows the waveform of these rebound vibrations of the piston rod. As can be seen from FIG. 15 of the drawing, the "rebound vibrations! ¹ are significantly reduced by the flexible O-rings 13 and 132. By eliminating these" rebound vibrations "it is possible to give the magnet coil a sinusoidal voltage

909821/0454

COPY

with variable amplitude! without causing instabilities or noises arise. With the aid of the control circuit C described above, improved control can be achieved. It however, completely satisfactory results are obtained even when a sinusoidal voltage with a variable amplitude is used.

The existence of a single stability situation can be explained by that the valve piston 18 is at rest at the start of a force cycle. This is also the reason for the benefit of using a controlled rectifier results as a voltage source. In the case of the previously described Embodiment, an amplitude control of the sinusoidal voltage source is not as effective as it is not possible achieve a state of rest during the period of rebound vibrations. If the rectifier is used, however, this follows Force pulse has a longer period, a rest period or a negative cycle in which the solenoid does not generate any force will. The vibrations of the valve piston are thus dampened and extinguished before the next pulse occurs. When using a sinusoidal voltage, a force pulse is generated even during the negative half-wave, and it is necessary to stop the vibrations before beginning to cancel this half-wave.

9 09821/045 4

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-πΊτΊτια n-nqTiiifsIa ^ ali ^ »»

Accordingly, it has hitherto been necessary for a wide dynamic range of a control valve.es to use an oilikongegierte rectifier. By eliminating the axial "rebound vibrations" however, it is possible to excite the solenoid 3 with a sinusoidal voltage. Due to the fact that the vibrations of the valve piston extinguish very quickly, which occurs through both axial and radial vibrations on the valve seat, there is no longer any need to provide a rest period or negative cycle.

As already mentioned, FIG. 14 of the drawing indicates an evaluation from "screen echoes", the voltage, the magnetic force and the stroke of the piston are represented. 14 relates to one Operating state in which the piston just like an electric motor

generated a voltage during the rest period. Due to the fact shutdown thing that the main control circuit is immediately after the controlled rectifier without energy, is along the solenoid to observe a charge .-- The sudden change in the speed of the valve piston produced when it hits the valve seat a relatively large "tension echo". By measurements using a

909821/0454

-4T-

OszUloskopes can determine the "rebound constant".

As already mentioned, in Fig. 15 of the drawing the "rebound vibrations" of a valve according to the invention, which is provided with the two O-rings 131 and 132. The aforementioned method however, it can no longer be used here to measure the "echoes". The "rebound vibrations" are too small and occur up too quickly for it to be possible to measure them on the fluorescent screen of an oscilloscope. The "echoes" that are the "rebound vibrations" of the piston rod can, however, as can be seen from Fig. 15, be estimated fairly accurately. It shows that the time of the last impact is significantly shortened, so that there is a period of rest between two successive ones Force cycles is not necessary. As a result, it is easily possible to use a sinusoidal voltage with variable amplitude, without causing any instabilities.

Valves with improved valve seats and valve pistons

It is possible to manufacture electrically operated control valves A £ A3, which are designed similar to the control valve A, but have improved valve seats and with means for controlling the axial movement of the valve piston are provided.

9Q9821 / Q454

- 43 -

These improved valve devices k ^ and Ag are shown in FIGS. 16 to 19 in the drawing. The electrically operated control valve A2 is connected to a control circuit C according to FIG. 3 of the drawing. The valve A2 is provided with an outer valve housing 201 which encloses an approximately cylindrical coil housing 202. A helically wound cylindrical magnetic coil 203 is arranged inside the housing 202 and is provided with insulating rings 204 and 205 at its upper and lower ends, respectively. The insulating ring 205 is disposed on the top surface of a base plate 206 that forms part of the outer coil housing 202. A circular "flux plate" 207 is located on the insulating ring 204. The entire arrangement, consisting of the magnetic coil 203, the insulating rings 204, 205 and the "flux plate" 207, is pressed against the base plate 206 with the aid of leaf springs 208. As can be seen from FIG. 16 of the drawing, the leaf springs 208 are between the upper surface of the "flow plate" 207 and the lower surface of the upper boundary wall! of the Spulöngehäuses 202 arranged.

The coil housing 202 and the solenoid 203 are for receiving a Piston cylinder arrangement 209 is provided with a central opening. A cylindrical tube 21Q is fitted inside the coil case 202.

- 4fr-

arranges and has a central non-magnetic section that surrounded by two magnetic sections at the two ends. At the top of the tube 210 is a bolt 211 with a Nut 212 attached. The bolt 211 protrudes inwardly into the tube 210 and is with a still further inwardly extending Section 213 provided with a smaller cross section, whereby an annular receptacle 214 for a compression spring 215 is formed. At the section 213 is followed by an eye 216, the lower surface of which serves as a limiting surface and stop 217 for the valve piston. In the tube 210 a valve piston 218 is arranged, the vibrations and Can carry out vibrations and is provided with four axial recesses 219. The piston 218 is screwed in at its upper end, thereby forming a "head 220".

The piston 218 is turned off conically at its lower end at an angle of approximately 45 °. At the truncated cone 221 closes a bolt 222 downwards, which continues into a conical end. The angle of a cone surface line to the piston axis is likewise approx. 45 °, so that there is a total cone opening angle of 85 ° to approx. 95 ° with a preferred value of 90 °.

909821/0454

The base plate 206 has a threaded opening on, into which a valve body 224, which is also provided with a thread, can be screwed. The valve body 224 is with a large liquid chamber 226 provided with a liquid inlet 227 and a liquid outlet 228 in the valve body 224 is in communication. The openings 227 and 228 can be provided with internal threads for receiving pipe connections. The liquid chamber 226 is delimited by an upper wall 229, a side wall 230 and a lower wall 231.

Inside the chamber 226 is the valve seat 232, which essentially consists of a rigid sleeve 233 - preferably made of corrosion-resistant Steel or another corrosion-resistant material - and which is provided with an axial bore 234. The sleeve 233 is provided with a conical depression 235 at the upper end.

In <the opening 234 of the sleeve 233 a tube 236 is pressed, the preferably made of polytetrafluoroethylene, mixed polymer of butadiene and acrylonitrile or synthetic rubber made of fluoroelastomers and which is provided with a valve seat 237 at its upper end. The valve seat 237 rests against the cone 235. The tube 236 is at its end 237 'something over the

909821/0454

Bushing 233 protrudes and thus partially protrudes into inlet 227. The seat between the tube 236 and the housing of the inlet 227 is so tight that a seal against the passage of liquid is ensured is. The cone angle of the conical valve seat 237 is approximately 80 to 84 with a preferred value of 82. It appears, that the noise caused by the flowing liquid is lowest when the angle of the cone 223 of the piston 218 has a value of 90 and the valve seat 237 with a cone angle of 82 °.

The tube 236 and the valve seat 237 can be made of any plastic exist. However, the best results have been obtained with polytetrafluoroethylene, but this has a certain tendency to creep has, which are weakened or prevented by the sleeve 232 target. On the underside of the sleeve 233 is a relatively strong ring 238 arranged, which is preferably made of the same material as the tube 236 and the valve seat 237 and for damping the impact of the piston 218 against the valve seat 237 is used. The ring 238 is thus preferably also made of polytetrafluoroethylene.

As previously described, the valve body 224 can only be released by loosening the screw connection 225 can be removed from the base plate 206. It is

909821/0454

thus in a very simple way possible the valve seat mechanism dismantle and replace if necessary. Due to the fact, that the valve seat mechanism is held within the chamber 226 by the end 237 ', the assembly 232 can by removing the Tube 236 can be withdrawn from housing 227.

The precise design of the valve seat assembly is very important with regard to secondary or "rebound vibrations". As already mentioned above, secondary vibrations are very undesirable because they are very disadvantageous with regard to the stability of the valve and cause a relatively high level of noise. Polytetrafluoroethylene as a material has the necessary coefficient of elasticity for a very large stable operating range and has therefore proven to be an excellent material for manufacturing the valve seat. ^r

As already explained above, the metal sleeve 233 allows the Eliminate creep and cold flow of polytetrafluoroethylene almost completely. Due to the fact that the valve seat 237 is made of polytetrafluoroethylene rests against the conical wall 235 of the sleeve 233, no displacements of the valve seat occur even when the piston impacts.

909821/0454

SS "

The noise when operating a control valve continued to decrease significantly thereby reduce that the piston 218 along its entire circumference and along its entire length with a film 239 made of polytetrafluoroethylene is wrapped. Here, however, care must be taken that despite this film 239 there is still a sufficient width of the annular gap remains between the outer wall of the film 239 and the inner wall of the tube 210, so that the flow medium pass through can.

If the foil 239 is not provided, the piston 218 has two stable vibrating positions at each "force level" of the solenoid. The transition from one of these two vibration levels to the other takes place within a period of approx. 0.016 seconds. instead, resulting in "flow constrictions" of approximately 5 %. When using a piston wrapped with the poly tetrafluoroethylene film 239, however, only a stable vibration position is observed and the noise is reduced to a value less than 0.2%. This beneficial effect of the foil 239 is mainly due to the fact that the friction between the cylindrical tube 210 and the piston 218 is reduced and that uncontrolled radial vibrations are dampened. A mixed polymer of butadiene and acrylonitrile or synthetic rubber made from fluoroelastomers can also be used as the material for the film 239.

2701 909821/0454

op

It has been shown that the noise can be further reduced, if in each of the four recesses 219 polytetrafluoroethylene strips 240 can be used, as is the case with the embodiment according to FIG. 19 of the drawing. In such an embodiment, a film 239 surrounding the piston 218 can be dispensed with. Due to the four strips 240, the two stable vibration positions are also reduced to a single one. Also with this arrangement is to provide sufficient clearance between the valve piston 218 and the inner surface of the tube 210 so that the liquid flow in the desired measure can take place.

Two leads for the magnetic coil are arranged through a connection 241. The valve arrangement is switched into the circuit C with the aid of the feed lines 242. ^r

As already stated above, the maximum achievable flow rate is and thus also the dynamic range of a control valve due to the "rebound vibrations" of the piston is very limited. In the aforementioned valve arrangement, the valve seat has in view of the fact that the piston moves back and forth at least sixty times per second, a considerable service life. This is due to the fact that the unbalanced forces of the piston are very small

909821/0454

sy

are so that the pressures in the valve seat are within the elastic range lie. In any case, the "rebound vibrations" of the Piston and through other uncontrollable vibrations the valve seat life reduced, whereby deformation of the Teflon seat cannot be avoided. Due to uncontrollable radial vibrations of the piston Certain leakage currents may even arise, which can be attributed, among other things, to a certain eccentricity of the opening in the valve seat However, these difficulties are met with an inventive method trained valve assembly avoided.

When the valve seat 237 is designed with a less acute angle is called the cone 223 of the valve piston 218, the latter tends to center itself in the valve seat 237 to some extent. Due to the conical In addition, the seat surface completely eliminates and eliminates the effects of "rebound vibrations". It can theoretically be proven that the energy normally consumed by high amplitudes of relatively slow vertical "rebound vibrations" of the valve piston is used up by the much faster side impact phenomena in valve seat 237. The energy that is otherwise in converts axial "rebound vibrations" of the piston 218, is thus converted into controllable, radial vibrations.

909821/0454

.se-

From Fig. 14 and 15 of the drawing is for both valve A and for valve A "the reduction in" rebound vibrations "can be seen. As already explained above, this is due to the design of the valve seat arrangement according to the invention are turned off, it is possible to supply a sinusoidal voltage with variable amplitude to the solenoid 203 without this creates any instabilities or additional noises. More effective control than that described above can be made achieve by using a control circuit C as shown in FIG. 3 of the drawing.

Further improvements can be made with an embodiment of a Valve arrangement with an improved valve seat and valve piston according to FIG Reach Figures 20 and 21 of the drawing. A control valve A "is provided with an outer valve housing 250 which encloses an approximately cylindrical coil housing 251. In the housing 251 is a arranged helically wound cylindrical magnet coil 252, which is provided at both ends with insulating rings 253 and 254, respectively. The insulating ring 254 is arranged on the surface of a base plate 255, which forms part of the outer coil case 251. On the insulating ring 253 there is a circular "flux plate" 256. The from the solenoid 252, the insulating rings 253 and 254 and from the flux

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-W-

plate 256 existing arrangement is with the help of leaf springs 257 against the base plate 255 pressed. The leaf springs 257 are between the surface of the "flux plate" 256 and the underside of the upper boundary surface of the housing 251 arranged.

The coil case 251 and the solenoid 252 are with a central Opening provided for receiving a piston-cylinder arrangement 258 serves, which is provided with a cylindrical tube 259 having a central, non-magnetic portion of two magnetic Sections at the two opposite ends is surrounded. At the upper end of the tube 259 is a bolt 260 by means of a nut 261 attached. The bolt 260 extends inwardly into the tube 250 and has a portion 262 of smaller diameter that still extends extends further inward and forms an annular receptacle 263 for a compression spring 264 here. The section 262 is followed by a Projection 265, the lower surface of which acts as a stop 266 for the valve piston serves. A valve piston 267 is movably mounted in the tube 259 and has four axial recesses 269 for receiving liquid is provided. At its upper end, the piston 267 has a Turn on, whereby the "head" 269 'is formed.

At the lower end of the valve piston 267 is the same with a conical Chamfer 270 is provided which has an angle of approximately 45 °.

909821 / 0A5A

A bolt 271 with a reduced cross-section, which is provided with a flat valve seat 273, adjoins the bevel 270.

The base plate 255 is provided with an internal thread which is used to receive an upper part 274, which is also provided with a thread of the valve body 275 is used, which corresponds essentially to the valve body 224. The valve body 275 is provided with an inlet port 276 and an outlet opening 277 which are in communication with a relatively large internal liquid chamber 278. The boundary surfaces of the chamber 278 are defined by an annular side wall 279 of

a top wall 280 and a base wall 281 are formed. The openings f ; 276 and 277 define inlet 282 and outlet 283 of chamber 278, respectively.

j ■. ^l - -

The openings 276 and 277 can be internally threaded for receiving

• a common pipe connection must be provided. ' ^r

In the chamber 278 a seat mechanism 284 is arranged, which consists of a cylindrical sleeve 285, which is preferably made of corrosion-resistant steel and is provided with a central axial bore 286. The axial bore 286 merges into a cone 287 at its upper end. A polytetrafluoroethylene tube 288, which is provided with an outwardly directed valve seat 289, is arranged in the axial bore 286. The tube 288 is an interference fit in the

₂₇₀₁ ■ 909821/0454

Bore 286 attached, creating a seal against fluid penetration is achieved. The seat 289 also rests firmly against the cone. The taper angle of seat 289 is approximately 80 ° to 84 ° with a preferred value of 82. Between the sleeve 285 and the lower boundary surface 281 of the housing 275 is a polytetrafluoroethylene ring 290 inserted.

As already stated above, the polytetrafluoroethylene material the effect of secondary or "rebound vibrations" on piston 267 is significantly reduced. It was able to do through numerous attempts found that polytetrafluoroethylene is an excellent material is suitable and has a sufficiently high coefficient of elasticity

and also guarantees a stable operating range.

A ball 271 made of hard, corrosion-resistant steel is arranged below the seat surface 273 of the valve piston 267. The ball 291 of valve A ₃ corresponds to the conical lower end of the valve piston of valve A ₃ . The axial movement of the piston 267 is limited so that the ball 291 cannot under any circumstances move away from the cone of the valve seat. As the piston 267 reciprocates during controlled operating oscillations, the seating surface 273 presses the ball 291 against the seat 289. The upper conical portion 287 of the sleeve 285 allows for some deformation and creep

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of the Teflon seat, due to the fact that the Teflon tube 288 is too protruding to a certain extent into the opening or recess 276 is a very simple assembly and disassembly of the entire valve seat arrangement 284 possible.

Even with an arrangement as described above, it is possible to to obtain very easily controllable and controllable radial oscillations and vibrations. The conical seat surface 289 is eliminated completely eliminates the effect of axial "rebound vibrations" as the ball 291 is capable of very rapid radial vibrations. It can also be demonstrated theoretically here that the energy normally generated by axial "rebound vibrations" of the valve piston 267 is consumed, is destroyed by very rapid lateral movements and vibrations of the ball 291 in the seat 289. So it is possible, the valve A ", i.e. the solenoid 252, a sinusoidal voltage with variable amplitude without causing any instability or noise would occur.

The valve A "has a connection 292 for receiving two lines 293 provided for the solenoid 252. Lines 293 are switched into circuit C.

0-9 821/0454

The "rebound oscillations" and vibrations of valve A ₃ can also be seen from FIG. 15 of the drawing. It can thus be seen that the axial "rebound vibrations" of the valve piston 267 are reduced by controlled radial vibrations even in the case of a valve according to embodiment A _3.

The noise of a valve A ₃ generated by the liquid can be significantly reduced by surrounding the piston 267 with a polytetrafluoroethylene film 294. Without this film 294, the piston has two stable vibration positions for each "force level" of the magnet coil. As with valve A ″ and valve A ″, the transition from one of these two positions to the other takes place in a time of approximately 15 milliseconds, with fluctuations of approximately 5%. If the piston 267 is surrounded by the foil 294 along its circumference and its entire axial length, these two stability positions are reduced to a single one, the noise of the liquid being reduced to a value of less than 0.2%. The explanation for this very favorable situation is the fact that the friction between the outer surface of the piston 267 and the inner surface of the tube 259 is reduced to a minimum and that the uncontrolled, radial vibrations are dampened. It is of course to be ensured that between the surface of the film 294

909821/0454

. «Β-. 15QQ165

and the inner surface of the tube 259 has enough clearance for the Passage of the liquid remains.

It is also possible to reduce the two stable states to a single one with the aid of polytetrafluoroethylene strips which are inserted into each of the four axial recesses 269. With such a measure, too, it is found that the fluctuations and constrictions are reduced starting from the value of 5%, as is the noise, which is reduced to a value of less than 0.2%. Here, too, care must be taken that there is enough space left between the piston 267 and the tube 259 for the liquid to pass through; } ■ - ■ -: -. '<' ; ^: '' ■ ■ ^! - ^:

Theoretical considerations regarding the operation of the valves A,

A ₁ , A ₂ and A ₃

Consideration of the operation and working of a solenoid operated Control of the valves according to Fig! 1 to 21 of the drawing assumes that the piston is under the action of a magnetic force with respect to an opening executes certain vibrations and that a control of the liquid flow is carried out by controlling the amplitude of these oscillations.

■ 909821/0454

A quantitative description is based on this fact of the tax area that can be reached during operation »

Such an approach that assumes that the controller the flow of liquid is carried out by controlling the movement of the piston rod, there are two basic requirements »The first requirement can be seen in the fact that the maximum magnetic force generated by the magnetic coil must be greater than the resultant from the spring force and the gravitational forces that push the piston against the seat Press ,, If this requirement is not met, you will not find any Vibrations of the piston take place. The second requirement is based on that the magnitude of the magnetic force on the average of a work or force cycle is less than the force exerted by the spring. If this requirement is not met, the piston would be stopped for at least part of the cycle, which is the usual Hysteresis and instability of the familiar solenoid operated Valves would result. Indeed, it must be due to dynamic instabilities the average force must be less than the theoretically resulting average force. Furthermore, the effective The valve area and thus the flow rate correspond to the time integral of the valve lift be proportional over a force cycle.

90 9 821/0454

-β * - 15Q016S

The wide dynamic range of the invention described above Valves is explained above all by the fact that there is almost no friction at all, which causes vibrations and oscillations very low amplitude are possible. Although the valve piston at least oscillates back and forth sixty times per second, the valve seat has a relatively long service life because it is not in equilibrium forces-the piston · are very low, so that the maximum

Contact pressure in the seat within the elastic range of polytetrafluoroethylene lies.

Due to the present stability criterion, i. H. due to the fact, that there is no movement at the beginning of a force cycle, it is possible, i. H. advantageous to use a controlled rectifier as a voltage source and to achieve excellent controllability, while amplitude control of a sinusoidal voltage does not give good results. Due to the use of a controlled The rectifier follows a force pulse for a longer period of time, the "rest period" or negative cycle, in which by the solenoid no force pulse is generated. This will cancel the vibrations before the next pulse begins. In comparison, will in the case of a sinusoidal force, a corresponding force pulse is generated during the negative half-wave, and it is necessary to reduce the vibrations and

₂₇₀₁ 909821/045

To cancel out vibrations before this half-wave begins. A reduction vibration with a sinusoidal power source limits the operating range of the controller. It is therefore with the help of one by one controlled silicon rectifier controlled power source a much larger dynamic control range can be achieved.

"Reverse" control valve

In Figs. 22 to 25 of the drawings, a further preferred embodiment, A ₄ is shown a control valve of the invention. The valve A ₄ is switched on in a control circuit C ₄ according to FIG. 26 of the drawing.

r control valve A ₄

The valve A ₄ is provided with an outer valve housing 301 which encloses an approximately cylindrical coil housing 302. A helically wound, cylindrical magnet coil 303 is arranged inside the coil housing 302, which is provided with an insulating ring 304 and a further insulating ring at its upper and lower ends. The insulating ring 305 is on the surface of a base

909821/0454

Plate 316 is arranged, which is part of the outer coil housing 302 forms. On the upper insulating ring 304 there is a circular "flux plate" 307. The one from the magnetic coil 303, the two insulating rings 304 and 305 and the "flow plate" 307 is pressed against the base plate 316 with the aid of leaf springs 308. The leaf springs 308 are arranged between the surface of the "flow plate" 307 and the underside of the upper boundary surface of the housing 302.

The coil housing 302 and the solenoid 303 are with a central Provide opening that receives a piston cylinder arrangement 309 which is provided with a cylindrical tube 310, which has a central, Has non-magnetic section, which is made up of two magnetic sections is surrounded at the two opposite ends. A cylindrical * Bolt 311 is inserted into the top of tube 310 and extends inwardly into the housing. The bolt 311 is with a liquid inlet channel 312 which communicates with the interior of the cylindrical tube 310 in communication. The bolt 311 has furthermore a recess with an internal thread 313 for receiving a conventional pipe connection. In the lower part of the bolt 311 this is turned off, whereby a section 314 is formed with a reduced cross-section. This section 314 is followed by a paragraph 315 formed. A lower boundary surface 316 of the section

9821/0454

serves as an upper stop for a piston. The liquid channel ends down in an opening O.

A cylindrical valve piston 317 is movably arranged in the tube 310. A certain gap is provided between the valve piston 317 and the pipe 310 for a flow medium to pass through. To avoid any undesirable vibrations and oscillations of the valve piston 317, this is to be avoided with four axial recesses

P olytetrafluorethylene coated, which serve to accommodate tires 318 and which are dimensioned so that the piston 317 is only axial, but not can perform radial movements. The piston 317 is thus only axially movably guided in the tube 310.

Further axial recesses can be provided in the piston 317 for the flow of a flow medium Piston 317 takes place between an upper limit 316 and a lower limit 319, which is attached below the tube 310 - see FIG. 23 is. The boundary surface 319 is provided with an opening so that the liquid can exit from the tube 310 and into a Connection 320 can flow over with an outlet opening 321. The connection 320 is provided with an internal thread for receiving a pipe. A valve seat 322 is provided on the upper end of the piston 317

909821/0454

1500

see and consists essentially of a projection 323 with a annular shoulder 324. A ring 325, which is larger in diameter, is provided on the shoulder 324, resting firmly against the same is than the projection 323 and from the upper boundary surface of the piston 317 protrudes upwards. The ring 325 is preferably made of a suitable flexible plastic or rubber, e.g. made of polybutadiene rubber. A rubber that is very suitable for this purpose is e.g. B. a Copolymer of butadiene and acrylonitrile. The piston 317 is pressed down by a compression spring 326, which against the shoulder 315 of the bolt 311 and against a contact surface 327 of the piston 317.

However, if it should be desirable, the spring 326 can be omitted. The advantages that arise when using a spring ^r 326 are explained in more detail below. The ring 325, which must consist of a relatively flexible material, serves to seal the opening O in the lower surface 316 of the bolt 311 in an airtight manner.

The material from which the ring 325 is made has a large one Influence on secondary and "rebound vibrations" of the piston, which, like already set out above, affect the desired stability and moreover cause a relatively loud noise. It has become

909821/0454

shows that with mixed polymer of butadiene and acrylonitrile very good Results are achieved. Other suitable materials are: chloroprene, various polybutadiene-styrene rubber materials, etc. These rubber materials have the advantage of good flexibility at low temperatures.

The valve A ₄ is provided with a connection 328 for receiving two lines 329 for the solenoid 303. The lines 329 serve to connect the valve A ₄ to the control circuit device C ₄ .

24 of the drawings is a modified embodiment of the valve seat 330 is shown, which is designed similar to the valve seat 322 described above. The valve seat 330 is circular with a Recess 331 is provided, which is at the upper end of the valve foliage 317 is located. The recess 331 is formed so that they have a Ring 332 is able to hold firmly. The ring 332 corresponds essentially to the ring 325 described above. It is possible to use the ring 332 to be glued inside the recess 331. The thickness of the ring 332 is chosen so that this over the upper boundary surface of the KoI-. bens 317 protrudes and can come into contact with the lower surface 316 of the bolt 311.

90 98 21/0454

Referring to Figure 25 of the drawings, there is another preferred embodiment a valve seat shown. The valve seat 333 is then used, if a slightly steeper and more rigid material than polytetrafluoroethylene Desired for the seat 1st. The 833 seat has a polytetrafluoroethylene bolt 884, which is firmly inserted into a circular recess in the upper end of the valve piston 317 »The bolt 334 protrudes somewhat beyond the upper boundary surface of the valve piston 317 and is provided with an upper, annular, pointed hand 836. As Fig. 25 of the drawing can be seen, this hand 336 is against the Surface 316 and surrounds the opening O. Due to the fact that the Edge 386 is pointed, takes place after a first contact with the ring 336 the surface 316 shows some deformation of the polytetrafluoroethylene material instead of. As long as the valve piston 317 is held invariable in the axial direction, an excellent liquid seal is achieved.

Polytetrafluoroethylene has a certain ability to cold flow, whereby certain manufacturing inaccuracies, such as. B. eccentricities, im Valve seat to be compensated. The prerequisite for this, however, is the fact that no radial relative movements between the piston and the Bolts 311 take place. For this purpose there is another in the bolt 311 small bolt 337 is provided, which also engages in the piston 317, so that through the bolt 337 of the bolt 311 and the

9098 21 / (H 5

Pistons 317 are centered radially to one another. The recesses in however, as can be seen from FIG. 25 of the drawing, the bolt 311 and in the piston 317 are designed so that axial movements of the bolt 317 cannot be affected by the small bolt 337.

Control circuit C.

The control circuit C shown schematically in FIG. 26 of the drawing. is provided with a 120 volt AC voltage source, not shown. Two lines 350 and 351 are connected to a diode bridge circuit 352, which consists of diodes 353, 354, 355. There is also an equalizing potentiometer between the two lines 350 and 351 P switched on. At the two opposite connections of the diode bridge 352 are a B + line 357 and B- - line 358 connected. A connection of the solenoid 303 is connected to the B + line 357 and the diode bridge 352. The opposite Connection of the magnetic coil 303 is directly connected to an anode 359 of an auxiliary-controlled rectifier 360, which with a grid 361 and a cathode 362, the latter in turn, is in direct connection with the B- line 358. A “free” diode 363 is connected in parallel with the solenoid 303.

909821/0454

If desired, a temperature-compensating resistor, a thermistor (not shown), can be connected between the electronic rectifier 360 and the magnetic coil 303 in order to compensate for undesired temperature influences. The ignition angle of the output voltage of the control circuit C ₄ to the solenoid 303 is determined by

ι ■ - I

the changes in the physical variables to be measured are controlled. These changes are measured in the form of a control voltage, which is generated by a suitable electrical Control and control device is generated *

To control the ignition angle of the circle depending on the Measured changes in the physical variable is used by a transistor 364, which has a 1-base 365, a 2-base 366 and a Emitter 367 is provided. The 2 base 366 is about a temperature compensating Resistor 368 connected to B + line 357. The 1 base 365 is connected to the B line via a fixed resistor 169 358 in connection.

The emitter 367 of the transistor 364 is connected to a capacitor 370, which is connected to the B line 358. The emitter 367 is also directly connected to a collector 371 of a P-N-P-Tran-

sistor 372 connected, which is operated in a kind of emitter SchalUmg

-and with one

809821/04 54

Base electrode 373 and an emitter electrode 074 are provided; the

Emitter electrode 374 is above a resistor 375 with high impedance dane in connection with the B + line 357.

As already explained above, the ignition angle of the basic output voltage of the control circuit arrangement C ₄ is controlled by the changes in the measured physical variables. These changes are measured in the form of a control voltage which is represented in FIG. 26 of the drawing by a control voltage source 876 which is connected to the base electrode 873 of the transistor 372 via a terminal . The opposite terminal of the Steuerspannungequelle 376 is connected to the tap of a potentiometer 372 ', which is in communication with a terminal of the B + line 357, and a fixed resistor 378 to the B -Leitung 358. Between the B + line 357 and the B - Line 358 is also a Zener diode 379 switched on.

Operation of the control circuit arrangement C ^

As explained above / represents the control voltage source 373 the changes in the physical measured variable. The control voltage 376 can therefore be sent by any suitable recipient

BATH ORIGINAL

909821/0454

and donor mechanism are replaced to accommodate the changes a physical measurand is suitable and enables a conversion of the same into voltage changes. The ignition angle of the The output voltage supplied to the solenoid 303 is thus controlled by the changes in the physical variables to be measured. It can therefore all by means of a device according to the invention physical variables are measured, the changes of which are converted into electrical measurands, e.g. voltage and current changes, permit. .

The alternating current is fed to the control circuit C ₄ via a full-wave rectifier, in contrast to the control circuit described above, in which a half-wave rectifier is used. In a control circuit according to the invention, only a controlled one is used

Rectifier used, which is why the diode bridge serving as a rectifier 352 is used. The current is supplied by an electrical voltage source, generally an AC voltage transformer for 120 V output voltage, which feeds the diode bridge 352 with the diodes 353 to 356. The power is on during the positive half-wave thus through the line 350 to the Diode 353 and through the "load" i.e. solenoid 303 to controlled rectifier 360 when it is conductive. The current flows back through the controlled rectifier 360,

909821/0454

through diode 354 and line 351. When reversed, the flows Current through line 351 through diode 355 and through solenoid 303 when controlled rectifier 360 is conductive. Of the Current then flows from controlled rectifier 360 through diode 356 into line 350.

If there is a change in the physical measurand, a Control voltage forwarded to the control voltage source 376. This pulse is then passed on to transistor 372, which the Voltage converted into a current with high impedance. The Collective

Emitter port 371 has a very high impedance, so that the current inrTransistor 372 is passed through collector 371 to capacitor 370. In normal operation, the emitter 374 would be affected by the voltage the control voltage source 376 can be controlled. The size of the resistance 375 determines the current flow between the B- line 357 and the emitter 374 and thus also along the transistor 372. Accordingly the voltage across transistor 372 controls only a collector current as long as the current passes through collector 371. Of the Current passing through collector 371 charges the capacitor until it is fully charged. Hence becomes a constant Maintain current flow at transistor 364. The transistor 372 thus serves as a constant current source with a high internal resistance,

2701

909821/0454

regardless of the load connected to it and its voltage level.

Transistor 364, which serves as a relaxation oscillator, conducts one Current pulse from the 1-base 365 to the grid 361 of the controlled rectifier 360 on. This takes place in a controllable period in the cycle of the supply voltage of the electrical power source. When the controlled rectifier 360 receives a signal, it begins to conduct this until the polarity of the current is reversed. At this point the normal diode action stops the flow of current. A however, further current flow to transistor 364 occurs from capacitor 370. How the relaxation oscillator works is based on the principle of transistor 364, according to which conduction between emitter 367 and 1-base 365 is prevented when the emitter-to-base-1 voltage is greater than a critical value, the critical value being represented by the 2-base-voltage-to 1 base voltage is determined. When this voltage spike is exceeded becomes, the effective resistance between the emitter 367 and the 1-base decreases and reaches a value of zero. One Conduction would normally continue until the emitter-to-base-1 voltage falls below the minimum voltage, i.e. the valley voltage.

²⁷⁰¹ 909821/0454

The control voltage source 376, the feedback voltage, and the set point of the potentiometer 372 'determine the ignition time of the transistor 364. The transistor 372 thus ensures together with the capacitor 370 for constant current generation, the magnitude of the current being determined by the control voltage applied to transistor 372 will.

When transistor 364 is conductive, current will flow from base 373 of transistor 372 to emitter 367 of transistor 364 instead of. When transistor 364 is non-conductive, i.e. does not "ignite", the constant flow of current from emitter transistor 372 charges capacitor 370. When transistor 364 is conductive, it will discharge Capacitor 370 in the direction of the emitter 367 of the transistor 364. The maximum current in the non-ignited transistor 364 must be smaller than the so-called valley stream. The emitter 367 is generally biased until there is sufficient voltage across it has built. During the time that the voltage at the emitter 367 increases, the voltage difference between the 1-base 365 and the 2 base 366 constant. When the voltage at emitter 367 is critical When the value is reached, the transistor 364 ignites, the capacitor 370 being discharged via the resistor 369, so that in the grid 361 of the controlled rectifier 360 current flows in.

BATHROOM ORIGINAL

909821/0454

Δ t Vf L

As a result, the rectifier 36O ₁ ignites, the magnetic coil 303 being supplied with current. If the control current is less than the critical value, the capacitor 370 is not charged to the ignition voltage at the end of the positive cycle. When transistor 364 fires, capacitor 370 immediately begins to recharge. The capacitor 370 can, if the current is high enough, re-ignite the transistor 36Ö before the end of the next cycle. If the controlled rectifier 360 is already conducting, this additional pulse generated by the ignition of the transistor 364 has no further influence.

In the electrical circuits where an active resistor is used there is generally a long idle period between the current pulses. In Fig. 27 of the drawing, the current pulses are shown, which are generated when the solenoid 303 a Has inductive load. In Figure 28 of the drawing are the current pulses shown, which arise when the solenoid 303 is an operator stand has. In the present case, there is no idle period because there is an inductive load and the current pulse is as shown in Fig. Has the shape shown. It is known that with an inductive Load the current lags the voltage so that the voltage is zero when the current is still flowing through the controlled rectifier, so that consequently the rectifier cannot switch off. In the case of one

₂₇₀₁ 909821/0454

inductive "load" can cause the current to drop. The next voltage pulse is so close, however, that the -s4 & ike »controlled rectifier is still conducting remain.

With the aid of the "free" diode 363, however, this problem is overcome. When the current to the solenoid controlled rectifier 360 is discontinuous is supplied, it flows in a circular manner from the solenoid 303 the "free" diode 363. This is the case when the voltage is on Rectifier 360 is large enough so that it can switch off. if If this occurs, an inductive drop is recorded, as shown in FIG. 30 of the drawing. The curve of FIG. 29 applies to a waveform that is achieved when the "free" diode is switched off is. The current does not go to zero at any point and reaches a slightly higher minimum until an equilibrium state is reached, for example according to Fig. 31 is. There is thus a minimum and a maximum current level. As can be seen from Fig. 31 of the drawing, there is a critical one Voltage at which the rectifier 360 fires.

From the foregoing it is readily apparent that the Eiiiweg-

Silicon-

S4Uke »rectifier, which together with control valve A in the

Circuit (^ is used, the "Revereier procedure" described above would not allow. As already stated, this is on

909821/0454

- «β- 150Q1§§

attributed to the long period of the negative half cycle in which none

magnetic force is generated, so that the valve A is in the position

Two way setting "open". With a rectifier

however, this problem is overcome. In the circuit C ₄ described above, the maximum magnetic force arises shortly after the ignition of the Öütiseegesteiierten rectifier, which takes place twice during each cycle of the supply voltage. After the

-feed controlled rectifier reaches the. Current a maximum and

,the

then drops to a point where the / voltage in the solenoid is reversed. At this point, the "free" diode diverts the coil current from the controlled rectifier, allowing it to do so. The coil current is consumed by an em- ■ drop in the coil. This inductive drop, which is shown in FIG. 30, lasts until the next ignition of the

Rectifier on when the cycle starts again. The amplitude of the

Vibration of the piston can be increased by decreasing the minimum value of the current or by increasing the time
in which the current is lower than the critical O vibration current,
is enlarged.

909821/0454

-η-

Theoretical consideration of the mode of operation of the control valve A ₄

In the above, regarding the operation of the control valve A stated that the piston executes vibrations relative to an opening, which takes place under the action of a magnetic force and that the flow is controlled by controlling these oscillations of the piston. Because of this perspective, there was one quantitative description of the controllable operating range possible.

For a normally closed control valve A, two

maximum

Basic requirements apply. The / magnetic force generated by the solenoid must be greater than the resultant of the Spring force and the gravitational forces that press the piston against the valve seat. The average magnetic force of a work cycle must be be less than the force exerted by the spring.

The control valve A ₄ is a normally open control device,

in which the movable piston is pushed away from the seat 316, what

combination

by any of the forces, e.g. the force of the spring 326, the inertia force, or the differential pressure force.

909821/0454

- «· - 15Q01?

As stated above, the spring force is not necessary as the gravitational forces and differential pressure forces are sufficiently high after have downwardly directed components for actuating the valve piston 317. The magnetic force that moves the piston to the "closed" position

pulsating constant

sen "is generated by a / Äfecfcoaistrom whose average Size is sufficient to overcome the opening preload. However, the minimum magnetic force is smaller than this preload force. The piston is thus pressed against the seat on the average, with relative movements with respect to the seat being caused by a current reduction which accompanies the so-called negative impulses.

The magnetic force of the solenoid 303 must of course be a direct current component that is large enough to press the valve piston against the upper stop 316. If the open position is chosen no biasing spring is required to open the valve. Having a large seat is when the balance of forces is used ensures that the response time of the valve by controlling the magnetic current flowing to the magnetic coil accordingly can be regulated. As with the normally closed valve, this can be done with the help of a pulsating current or without a Pulsation of the current can be achieved.

909821/0454

- «- 150015

9ε

It is important that the ring 325 works well together with surface 316 is sufficiently flexible to allow fluid flow is avoided when the piston 317 is in its uppermost position. To the same extent, however, the ring 325 must be sufficient Have rigidity to prevent metallic contact takes place between the piston 317 and the bolt 311.

With a control valve designed according to the invention, it is possible to lower the "current level" below the critical "ignition level" without a flow of liquid takes place. This is because for relaxation and deformation of the ring 325 are not sufficient Time is available.

■ ■■ · j

In Fig. 31 the current in steady-state equilibrium is AurgfttteUt, which!

is generated by the aüttksn-controlled rectifier 360. If the If the minimum "current level" is lowered, it falls below the critical "current level". However, the valve piston is not moved enough to: allow fluid flow. The magnetic one acts here Force versus differential pressure along the valve. With such a balance of forces, the piston 317 does not vibrate. A vibration, however, is desirable to be due to a suitable Average value that otherwise normally occurs due to hysteresis Turn off problem.

909821/0454

15QO1§5

The hysteresis is based on the deformation force of the seat and the magnetic influence that arises when the piston 317 in its uppermost position, i.e. into its closed position, is moved. When the magnetic force equivalent to the square of the current of the coil 303 is plotted as a function of the differential pressure force, then theoretically a linear relationship results. However, your reality arises a hysteresis. However, this hysteresis is compensated for by vibration of the valve piston in such a way that, on average, a linear one Relationship arises.

Valve A * can also be used as a control and switching valve like valve A. In this case, a connection takes place when the valve A _{4 is connected} , as can be seen in FIG. 5 of the drawing. However, the operation is reversed wit that of the valve according to Fig. S of the drawing. .

The valve A ₄ can also be used to control a liquid level according to FIG. 4 of the drawing or as a pressure control device. It can also be used as a "force equilibrium device".

The valve A ₄ can thus be used in the same cases as the valve A, with the difference, however, that the valve A ₄ in comparison to the valve A according to the "reversing process"

909821/0454

is working. The valve A, can with the flexible rings 131 and 132, as well can be used with the improved piston and valve seat of valve A.

Further details and features of the invention are from the following Description of some exemplary embodiments can be seen.

Example 1 "

The control valve according to FIG. 1 of the drawing is equipped with a control circuit interconnected according to FIG. 3 of the drawing in order to observe the effect of the control variables which have an influence on the operation of the valve to be able to. A Hok-S 90 3020 CT solenoid valve was used with the following dimensions:

Piston weight 16 g

Flask outer diameter 0.92 cm

Piston stop outer diameter 0.84 cm

2 piston cross-sectional area 0.67 cm

effective axial piston length 4.4 cm

outer housing, outer piston diameter 4.1 cm

Thickness of the outer case 0.159 cm

- • β »-

15-016

Opening diameter 0.076 cm

Outer opening diameter 0.203 cm

effective opening diameter 0.094 cm

Air gap when the piston rests in the valve seat o.125 cm.

The solenoid of the control valve is by the following sizes characterizes:

Total number of turns 4,000 DC resistance 265 Q

Wire size (including compensation resistor) 33 ga

Spool inside diameter 1.35 cm

Spool outer diameter 2.98 cm

Spool height 3.15 cm.

Polytetrafluoroethylene

The valve is fitted with an inflatable seat and is made of corrosion-resistant steel. A corrosion-resistant steel with the type designation 430 F is used, which has an initial permeability of 200, a maximum permeability of 1,400 and a saturation flux density of 14,000 gr. The opening seating area becomes approximate
0.125 mm thick machined and finally with a
1,800-grit diamond polished to a high gloss. Here is an annular

909821/04 54

Seat made, which has an outer diameter of about 2.0 mm and an inner diameter of about 0.75 mm.

The individual elements of the circuit according to FIG. 3 of the drawing are listed below.

909821/0454

Cadmium sulfide converter

■■ β »-

90

15QP155

resistance 64 resistance 64 resistance 53 resistance 55 resistance 44 Thermistor 43 Arrester 57 capacitor 52 diode 56 Zener diode i58 "Unijunction ^{11 transistor} 46 flilieeiigegierte equal
judge 40 Potentiometer 51 Potentiometer 50 Potentiometer 63

Constant voltage transformer

Light and receiver (relay removed) Sigma 8ROIA

10 K l / 2 watt

3500 10 watts

300 1 % accuracy 2 watts

100 2 watts, 1 % accuracy Fenwall LA23J2

Sarkes S-491 140V RMS 0.1 200 MFD

IN 1695

IN 1779 22 V

2N1671A

2N 1597 200 PIV 1.6 A

100 K 4 watt wire wound Mallory MlOOMPK

10 K 4 watt wire wound Mallory MlOMPK

100 K 2 watt carbon ohmite CLU1041

Sola Cat. No. 23-13-060 60 V. A. at 115 V.

909821/0454

- ■ it -

The large dynamic range of a control system according to the invention can be seen from Figure 32 of the drawing, where the flow rate is plotted as a function of the control resistance and the ignition angle is. The average deviation y of the individual test results from the ^ shown in FIG. 32 resulting as an average value Curve is * 0.28 k-A- or - 0.5%. These deviations were found during an experimental period of approximately 3 weeks. For shorter periods of, for example, only one hour the deviation was approximately 0.15%. It became a long-term one Stability test carried out over a period of 2000 hours to determine the wear on the valve seat. Even after For such a long period of time, no significant wear could be noticed.

It has been shown that the dynamic range of an inventive Control valve is approximately 100 times larger than that of the previously known Control valves. A receiver and transmitter of a control valve A according to the invention works approximately 10 times faster than previously at Control valves used devices of this type. The influences of the individual elements that affect the mode of operation of the control valve are set out again in detail below.

909821/0454

- M- - Influence of the piston stroke

To adjust the flow rate through valve A to the average Stroke of the piston. it is necessary to refer to the flow rate at to measure a constant known piston stroke. In such an attempt, the flow of nitrogen becomes in the critical range measured. Above the critical pressure ratio, a critical flow could be realized experimentally. The magnetic

Properties of the valve can be used to determine the

Polytetrafluoroethylene

known lifting conditions. A UefifflBS disk is made using an adhesive bonded to the piston over the normal seat so that it is possible to get a "zero stroke". A millimeter ruler is attached to the outer cover of the valve body. When the valve is under the action of a known upstream Pressure is applied, the body rotates and the zero point of the flow is measured with an accuracy of 0.0005 cm with that of a voltage of 110 volts supplied solenoid. The piston is constantly pressed firmly against the upper stop. By by rotating the valve body through a certain angle, the actual stroke can be precisely determined.

The nitrogen pressure measured upstream is 2.38 ata, while atmospheric pressure at a temperature of 24 ° C prevails in the valve.

909821 / (H54

15QO155 - * »-S3

The flow is controlled by a Hoke - S 90 320 CT solenoid valve measured that an opening with a diameter of 0.78 mm and

Polytetrafluoroethylene

owns a JEeöBW seat. The annular seat has an outer diameter of 2.0 mm and an inner diameter of 0.75 mm. There was an essentially linear relationship between the stroke of the piston and the flow rate. The flow rate in m / min STB was approximately 3, 7.10 times the valve lift in centimeters. After this calibration, it is then very easy to determine the flow rate on the basis of the calculated average stroke of the piston while vibrating, thereby ensuring independent monitoring of the experimental flow rates while vibrating is.

Influence of the "ignition" angle

The most important variable that influences the operation of the measuring device is the ignition angle of the pulse current supplied to the magnetic coil 3. At higher flow rates, there is an unstable operating range created by secondary or "rebound vibrations" which is due to the resilient seat material and an almost complete lack of gas damping. If a rubber seat is used, this effect disappears. The same is true

Polytetrafluoroethylene in the event that water is used as the flow medium and a

seat is used. Eliminating this instability causes the maximum flow rate increases by a factor of 10.

In any case, the upper amount of the flow is through the contact of the piston determined with the upper stop. If the ignition angle is increased above this point, the flow rate will drop at first slightly before it rises again. This can be accepted without further ado, although the touch of the Piston with the upper stop follows an irregular hysteresis. The lower limit of the controllable flow is almost completely determined by the quality of the seal between the piston, the opening

PolytetrafjiiQrälfeyleii

tion and the seat. With a! BeäpoBitz and a Differ With a pressure of around 1.7 kp / cm ^ the loss of weight is hardly measurable.

Influence of pressure

The influence of the pressure on the flow rate is very diverse. With low pressure differences or with larger ignition angles, the effective pressure is similar to the pressure in a valve with a certain * ten, fixed opening. At high differential pressures and ignition angles in near the minimum angle (zero flow) causes an

909821/0454

15001 ??

increase in pressure, a decrease in flow rate. A high one Pressure causes the valve piston to be pressed into the closed position, which takes place with a force which results from the effective cross-sectional area of the piston and the differential pressure. That power is coming in addition to the normal spring force that pushes the piston into the closed position and requires a larger ignition angle. the Differential pressure force thus sets the upper value of the pressure and / or the maximum opening diameter is a limit.

The effect of "zero flow" pressure was similar to that previously Hoke control valve described measured, with a helium flow

was adjusted from 0 to 175 kp / cm. The test results are shown in Table I below. With a mathematical model experiment it is possible to determine the differential pressure force and calculate the effective opening area.

909821/0454

15001BB

- -94 -

Table I.

Influence of the pressure at "zero flow" control resistor was at "zero flow"

Differential pressure (kp / cm) (k-fi.) Max.magnetic / \ F force (g)

OO 59 "5 303

1.4 59.2 314 0.55

7.0 58.1 356 0.53

21.0 55.8 450 0.49

45.5 52.6 595 0.45

173.0 28.7 (2290) (0.81)

The above results were achieved with an opening that had an outside diameter of <0.203 cm and an inside diameter 0.076 cm and an air gap of 0.10 cm.

The constriction at 21 kp / cm is roughly equal to the "proportional band" at 0.0 kp / cm and gives roughly a limit for the practical pressure range. Another area is automation possible. The critical flow state can be represented very well if the flow rate as a function of the differential values of the Control resistance between the "zero flow" and any other Point, which refers to an average stroke, applies.

9821/0454

1500IBB

Influence of viscosity

Experiments were carried out with gaseous and liquid flow media, for example with nitrogen and water, where eg "is showed that the influence of damping and viscosity is negligible at low vibration amplitudes »Nitrogen was used with a Pressure of about 1.4 kp / cm and at a temperature of 24 C used. The water had an inlet pressure of 2.8 kgf / cm and one Temperature of 10 ° C. The width of the air gap was 0.13 cm. In Table II below are the comparative values between water and nitrogen.

909821 / 045A

Table II Water through
flow (cm ³ / h) Flow rate N ₂ flow Influence of Viscosity on the 30th Equivalent
Water through
flow (cm ³ / h) 50 N ₂ flow
(cm ³ / min), STP 50 Control resistor (k ^ i •) 120 8th 70 0.5 200 11 130 0.6 470 20th 200 0.8 800 31 470 1.0 1200 72 850 1.5 1600 130 1300 2.0 2000 200 1700 2.5 2500 260 2200 3.0 3000 340 2700 3.5 3600 420 3070 4.0. 5100
Ϊ6000 470 4700 4.5 720 7800 5.0 1200 6-.0
9.5

909821 / 04S4

The control resistance was determined at "zero flow". The control resistance has a value of 9.5 kΩ when the piston touches the lower stop and water is used as the flow medium. The control resistance has a value of 6, OkQ when the piston touches the lower stop and the flow medium is nitrogen. The equivalent water flow rate for nitrogen was obtained ^{by "multiplying" the nitrogen flow rate in cm 3} / nm by a factor of 6.

Influence of the piston closing force

The influence of the force with which the piston is brought into the closed position was determined on the basis of the results with a position of the piston in its upper and lower position, with a change the force occurred, which corresponds to twice the weight of the piston Table III can be seen from which it can be seen that a relatively constant necking is obtained by such a change.

90982 1/0 A5A

1500161

AOO the flow rate Piston up Piston down ! ) Table ΙΠ Control resistor (K S 56.7 57.6 Influence the thrust on 56.1 57.1 difference 56.0 57.0 0.9 Water pressure 55.7 56.7 1.0 quantity (cm ³ / h) 55.3 56.3 1.0 O 54.2 55.3 1.0 10 52.0 53.0 1.0 30th 48.3 49.4 1.1 100 1.0 300 1.1 1000 20 3000 10,000

The above test results were compared with the already mentioned

2 th Hoke valve achieved, the pressure at the inlet 2.8 kp / cm and the temperature was 10 ° C. The width of the air gap was 0.13 cm, the opening diameter v0.135 cm.

Influence of the air gap

The air gap can be designed as a vertical stroke, starting from the seat to the point of contact, be defined with the upper stop. Based on test results it was found that the influence of the air gap is similar to the influence that is caused by a change in the spring force

9 0 9 8 21/0 4 5 Λ

acts, d. H. a certain constriction arises. This Influence could be determined with the help of nitrogen, whereby the body of the aforementioned Hoke valve by a certain angle was unscrewed.

Influence of the material of the valve seat

A total of four materials were tested for the valve seat in 2s: Polytetrafluoroethylene, Synthetic rubber made from fluoroelastomers, mixed polymer of butadiene and acrylonitrile and hardened steel. The steel seat pointed an almost perfect elasticity and generated very strong secondary vibrations and considerable high frequency noise. Steel is therefore ruled out as a material, especially since certain leakage losses do not occur are to be avoided. Synthetic rubber made from fluoroelastomers, which is quite soft; did not result in exactly reproducible values, because sometimes two meta-staoile stages of vibration were observed. Polytetrafluoroethylene * however, has the desired value of the coefficient of elasticity xfor a very wide, stable operating range.

üi-igig of the material for the valve seat can be improved - ■ Stability can be achieved in that radial vibrations of the ; Coibe.: ~ To be avoided. This may be achieved by that c ^ o upper end of the piston with 1.5 turns of an approx. 0.8 mm

909821 / 0Λ54

Polytetrafluoroethylene

strong W & BssMolie is wrapped. This creates a seat with a clearance of approximately 0.025 mm and prevents metallic contact. An audible noise is barely perceptible and the short-term stability in the open position is better than -5%.

Average strength

The average strength per cycle can be measured with the help of a scale
»Here the lower valve body is unscrewed, whereby the lower end of the piston protrudes from the piston-cylinder arrangement. With the main spring 15 the upper part is connected in a suitable manner to a three-beam balance, the lower surface of the piston being attached to the balance with glue. The vertical adjustment of the upper valve body and a suitable design of the three-beam balance allow careful adjustment of the air gap. The reading scale of the balance then gives a measure of the force of the spring plus the force of gravity which the piston against the valve seat in the position in which the solenoid 3 is still de-energized
presses. A power supply to the solenoid then results in a change in the deflection of the balance with the air gap width kept constant and thus a measure of the average magnetic force

909821/0454 '

at each pulse cycle as the type of attachment of the scale with shut off any vibration from the piston. If then at the valve this. When the air gap was set, vibration and flow started with a constant control resistance of approximately 60 kΩ. at At this value the average force is only 47 g compared to a value of 306 g of the spring force. From this it can be seen that a control is achieved by opposing the magnetic force the spring force acts, which is the case in the usual state of equilibrium.

Maximum strength

The maximum magnetic force generated during a stress cycle is one of the most important variable parameters that occurs in an electrically operated control valve must be determined. His accurate measurement is essential for a quantitative understanding of the entire control system. Due to the novel vibration phenomenon an exact determination of this maximum magnetic force is possible. The resultant of spring force and gravity can be very can simply be determined as a function of the air gap. For a specific one chosen air gap must namely the maximum magnetic

909821 / 0Λ54

Force will be equal to this resultant if the stress is along the Solenoid is adjusted so that vibration just begins. At the beginning of the flow, the * maximum magnetic force is therefore measured. The relevant measured values can be seen in Table IV below. Table IV is i.a. the change in the air gap to be taken when the control valve A is operated with direct current, sinusoidal current or with SCR current.

To determine the maximum force, there are two independent ones Criteria. The first is based on the occurrence of a low flow, the second on a noticeable change in sound a rod held against the valve. The "new sound waves" are generated by the vibrations of the piston in the valve seat and have a frequency much higher than the 60 Hz of the electrical cycle. The results according to these two criteria are consistent with one another within the measuring accuracy.

9821/0454

- in -

to table IV ο

Maximum force and electrical values at the start of vibration

Air gap (Om)

Maximum force (g)

^ j direct current (mA)

cd Sinusoidal current

°°, maximum current (mA)

¹ ^ l impedance (Λ.)

- Inductance (Henry) ⁺ '

^ ₁ SCR voltage with

* - E ₀ = 168.5 V

Firing angle 0.0965 0.1070 0.1197 0.1340 0.1502 0.1670 0.1593

Maximum current (mA) 22.4 30.2 42.1 62.3 94.4 139.1 119.5

irechnet with ironless resistance of 2000-A.

0.005 0.01 0.02 0.04 0.08 016 0 0.125 320 318 317 313 306 292 131.0
545
1,151 299 24.0 33.0 45.0 63.0 90.0 131 115.0 29.5
1205
3.26 37.5
1108
2.90 48.7
995
2.50 67.2
842
2.02 96.0
674
1,521 118.8
588
1,274

2701

1500155 AOb

Phase and ignition angle

A physical and mathematical model that is as accurate as possible

\
to obtain, it is also necessary to determine the ignition angle of the · βΐϋ ^

! »» Controlled rectifier as a function of the control resistor as precisely as possible. The measurements are carried out with an electronic timer, which is able to carry out time interval measurements with an accuracy of at least 1 microsecond. The triggering of this time switch was carried out with the voltage difference between the anode and cathode of the controlled rectifier. The measurement begins when the positive voltage reaches a zero value and ends when the voltage becomes negative. It is thus possible to obtain the ignition angle f by multiplying the ignition time, which is measured in microseconds, by the factor 60-10 ". The influence of the control resistor, the value of which is given in k ^ö , results in the following for determining the ignition angle Numerical equation in which R _{c is} the control resistance:

f = 0.4646 - 0.00526R_.

909821/0454

Determination of the "rebound constant ¹ " and the stability limits

The "rebound constant" is given by the ratio of speed of the piston after impact given its speed immediately before impact. The "rebound constant" is thus information about the kinetic energy destroyed when the piston impacts. It is not possible to reduce the "rebound constant" by doing this to measure that you let the piston fall on the seat, because this resulting surface pressure in the seat the elastic deformability of the Polytetrafluoroethylene used as seat material exceeds. Only when the valve is in normal operation are they when the Piston on the seat resulting pressures within the elastic Range of polytetrafluoroethylene.

When the voltage across the solenoid 3 is shown on an oscilloscope is and the valve works with relatively large amplitudes, which are below the unstable flow condition, can on the Oscillation screen a fine structure of high frequency can be observed, which after switching off an ignition pulse by the controlled Rectifier occurs, but before the next ignition pulse, i.e. during the rest period. These appearances are

909821/0 U 54

as sharp "echoes" on the weakening voltage curve every shutdown process follows. The amplitude of these "echoes" continues to decrease with each subsequent "echo". The same goes for regarding the distance between two successive "echoes". There are thus all "echoes" that correspond to the vibration of the piston, to disappear at a certain measurable point in time before the start of the next cycle.

The aforementioned phenomenon is shown in more detail in Fig. 7 of the drawing, in which the voltage, the magnetic force and the piston stroke are shown graphically. An "echo" corresponds to the state that occurs when the piston generates a voltage like an electric motor during the rest period. Due to the fact that the Main circuit immediately after switching off the e-controlled rectifier is without energy, only an "ironless" charge occurs along the magnetic coil 3. The sudden change in the speed of the When the piston hits the valve seat, it creates a relatively strong "voltage echo". It is therefore by means of an oscillating screen It is very easy to measure the rebound constant.

It can be shown that the ratio between neighboring "echoes" of a certain frequency is directly related to the desired one Rebound constant. You can now in a very easy way

909821/0454

Way to set up a geometric series, through which the first and the last "echo" in a frequency to the rebound constant in relation be set. However, measurement of this relationship is sometimes desirable as far as the "echoes" on the oscillating screen a weak horizontal "grating" occurs, whereby a accurate measurement becomes quite difficult. The dimensionless time between the "echoes" can be read directly on the oscilloscope and results from the horizontal distance between the first and the last "echo" divided by the horizontal distance between the Stress cycles. The initial speed of the piston can be determined by a model test, provided that the Difference in the "ignition angle" with "zero flow" and with real flow conditions is known.

Oscilloscopic observations of the secondary or "rebound vibrations" furthermore allow the stability limits to be established during the operation of the valve devices. When the ignition angle increases slowly the point at which the secondary vibrations cease approaches the beginning of the next ignition cycle. If the The ignition angle is slightly larger than is necessary for the "entry" of the vibration in the next cycle, the operation of the The valve is unstable and the piston strikes the upper one irregularly

909821/0454

Stop 17 on. It is therefore a good criterion for stability of the valve when the secondary vibrations have completely stopped, before the force of the solenoid 3 has built up to the size of the spring force of the following cycle.

Example 2

With the control system of Example 1, control of a liquid level was carried out. A photocell served as the receiver. A cadmium sulfide photocell was used as the basic converter, the resistance of which decreases with a slight intensity of light. A source with collimated Light was placed perpendicular and centered to the axis of a tube provided with liquid. To this end it was a 10 mm OD glass tube used as a level measuring device and with a Connected vessel containing water at atmospheric pressure. Due to the liquid in the tube, its refractive index is larger than that of steam, a beam of light is broken away to the side. The photosensitive cadmium sulfide transducer was, like can be seen from Fig. 4 of the drawing, switched into the control circuit and attached to the side so that a diaphragm through one of the ray of light broken away from the liquid was illuminated. The bezel remained dark in steam. The aperture was arranged vertically,

909821/0454

creating a height of about 18 mm above which the light intensity fluctuated with the level, was reached. Darkening occurred to a width of approximately 3 mm.

The return control device takes the place of the control device a 'reboiler level' of a fractionation column. From a supply line water is supplied to the vessel, the flow rate of which is regulated by a throttle valve. The outflow line from the vessel is connected to the inlet of the control valve, which has an atmospheric vent. It is thus with the help of the control valve within the desired proportional band and the proportional Range of levels, regardless of the intake amount, controlled. the The proportional band is set with the help of the potentiometer 9 5 and 93 according to FIG. 4 of the drawing.

The control valve was supplied with water at a constant pressure of 2.8 kgf / cm and a temperature of 10 ° C. The liquid level was set in the reaction vessel and the flow rate was measured with the valve. In Fig. 33 of the drawing are the results for two different settings of the shunt potentiometer “This shows the broad dynamic range of a control valve according to the invention. There is one

909821/0 ^ 54

-! ΊΟ -

tenfold change in flow rate compared to change in level. In one of the known control valves, these changes would make it necessary to change the valve setting. The sensitivity of the control circuit is still shown on the lower curve evident. By changing the level from 3.12 cm to 3.25 cm The change in flow produced results from a 0.7% weakening of the entire resistance of the circle.

Example 3

The application of the "force equilibrium valve" according to the invention is described below according to FIG. 8 of the drawing. From this the excellent stability can be seen over a wide operating range.

The Hoke solenoid valve S 9OA 380 CT according to Example 1 is equipped with a Provided exhaust pipe, which has an inner diameter of 1.25 mm. With regard to the "return condition", a constriction provided with a diameter of 0.25 mm. The valve body is designed so that the inlet opening is arranged directly below the valve seat, so that an "open position" in the Valve can be sustained.

908821/0454

The control circuit C according to Figure 3 of the drawing is used to illustrate the advantages of using the Differential pressure force arise. It has been shown that at the beginning of the flow through the valve, the vibration amplitude is very low and that the flow begins near the point of lift-off of the piston »If the maximum magnetic force is equal to the resultant the other two forces acting on the piston, the valve piston begins to lift from its valve seat. At a The differential pressure therefore determines the given maximum magnetic force along the valve seat the point in time at which the flow through valve A begins. There is thus a constant differential pressure upkeep.

The valve can be connected to either a liquid or gas supply line be connected. Any influence that contributes to an increase in the flow through the valve, e.g. B. by an enlargement the amount of gas or liquid or the pressure, as well as the pressure downstream of the valve due to the constriction. As a result, a certain pressure is generated within the valve chamber and the influence on the valve is reduced. This caused it "Inner feedback" stabilizes the flow characteristics of the valve, so that a linear control voltage and a linear loading

909821/045

Draw between the control voltage and the pressure between the valve and the constriction arise.

The seat area should therefore be as large as possible to accommodate the differential pressure to be able to use it as best as possible.

Example 4

An application example of the Ag valve is described below as well as the measures to eliminate the two vibration states. A Hoke valve S 90 A 320 TT is used in which the lower Valve body and valve seat assembly has been removed. At the lower end of the Hoke valve, the valve Aq was screwed according to the invention. An all-metal piston made of corrosion-resistant steel was used, the lower end of which is flat and planar Surface has been sanded. A valve seat shape that consists of a brass tube with an inner diameter of approx. 3.2 mm, the is provided with a 60 ° cone at its upper end, is used to manufacture a polytetrafluoroethylene tube. This in turn serves to produce a valve seat with a cone angle of 40 with respect to the pipe axis. The polytetrafluoroethylene tube has a length of approximately 16.8 mm and is inserted into a sleeve made of corrosion-resistant steel. The stainless steel liner is made of

909321/0454

1500155

a ring with an outer diameter of 7.95 mm and a Formed inner diameter of 3.91 mm. At the top of the can a depression with an angle of 82 is provided for the reception one end of the polytetrafluoroethylene tube is used. The ring thus serves as a limit for the polytetrafluoroethylene cone.

The lower end of the polytetrafluoroethylene tube goes into the inlet port of the valve 40 and pressed against the walls of the inlet so that a liquid seal is achieved. Between a ball with a diameter of 5.55 mm is placed at the lower end of the valve piston and the conical seat. With a all-metal pistons, as previously described, a slightly unstable flow condition was achieved. With different cone angles Further tests were carried out on the valve seat. The values of these angles were: 75 °, 82 °, 90 ° and 140 °. With an angle out of 82 stable results were obtained. A 7.95 mm polytetrafluoroethylene ring with a central bore with a diameter of 3.18 mm and a diameter that is approx. 0.125 mm larger as the steel part of the piston was inserted between the valve body and the steel liner. The polytetrafluoroethylene ring was fixed and prevented vibrations

2701

903821/0454

and vibrations of the steel liner against the valve body, thereby also the uncontrolled radial vibrations have been reduced.

A good way of working was with an air-flow valve achieved by using a variable voltage source, which makes the instabilities and "rebound vibrations" disappear were brought. From this it can be concluded that the energy is consumed by the contact surfaces on the valve seat, which in the individual by the collision and impact movements of the seat, valve and piston.

The high frequency noise could be very strong due to a radial Guide of the valve piston can be reduced. A 1.65mm star-

Polytetrafluoroethylene
ker -JPe & oft strips were inserted into the four recesses of the valve piston. These strips were tightly pressed in with flat pieces of steel so that a gap of approximately 0.05 mm was created in the lower part of the valve body. This prevented metallic contact. The radial vibrations were dampened so that only one-dimensional vibrations were observed.

Polytetrafluoroethylene Subsequently, a foil was placed around the Tentil piston and

inserted into the pipe in the upper part of the valve. The piston loads

909821 / 04S4

stanc made of a steel with the type designation 430 F and had an outer diameter of 6.35 mm. The outside diameter of the polytetrafluoroethylene film was 9.55 mm. The film was provided with a 6.25 mm hole for receiving the valve piston. The top of the same was cut off flush with the top of the valve piston. The "rebound vibrations" could be eliminated by the aforementioned measures. The same applies to the two vibrational equilibrium states.

example 5

The following describes an application example of the Ven es i-2 according to the invention, the measures being set out with which the axial vibrations of the valve piston and the two Yi

Let braticr. eliminate any conditions of equilibrium.

'2s wire, the Hoke valve is used again, but in which the valve ball is ciitferiv; became. The polytetrafluoroethylene valve seat had an angle of cu. 32 and the lower end of the valve piston has been ground to a 90 -Xe ^ eI designed to engage the conical valve seat. "As already described in Example 2, the valve piston was wrapped with a polytetrafluoroethylene film, whereby the two vibrations

2701 909821/0454

states of equilibrium could be switched off. In the same In this way, the rebound vibrations were greatly reduced.

Subsequently, the rectifier was controlled by an autotransformer to feed the solenoid. This showed that stable results together with very low "rebound vibrations" occurred. The valve arrangement thus works with a variable voltage source without instabilities occurring.

Example 6

The control valve according to FIG. 22 was interconnected with the circuit according to FIG. 26 in order to reduce the influence of the controllable parameters, which affect the operation of the ventües, study ^ it a Hoke Series 90 solenoid valve was used again, the corresponding of the present invention has been modified. The control valve had the following dimensions:

Piston weight 16 g cm Piston outside diameter 0.92 cm Outer diameter of the piston
stop 0.84 cm* KoI janquer cutting surface 0.67

909821/0454

Effective, axial piston length 4.4 cm

piston outer shell

diameter 4.1 cm

Thickness of the outer shell 0.159 cm

Opening diameter 0.178 cm

Air gap when the piston is in the closed position 0.00762 cm

The solenoid coil is characterized by the following information and values:

Total number of turns 4000

DC resistance (including the compensation

Resistance)
Wire strength
Coil inside diameter 265 ohms
33 ga
1.35 cm Spool outside diameter 2.98 cm Spool height 3.15 cm

The valve was then made from a corrosion resistant steel of the type 430 F, which has an initial permeability of 200, a maximum permeability of 1400, and a saturation flux density of 14,000 G. The orifice seat was relatively flat and totaled 5.09mm by 4.70mm. The outside diameter of the Opening was 6.23 mm.

909821/0454

The top of the piston was made to be relatively flat. Flttche sanded off uijd · covered with an opening. This opening pointed you Diameter of about 6.23 mm, with a depth of Ι, βδ mm. Inside this opening there was an O-ring at the top of the flask arranged from butadiene acrylonitrile. A polytetrelluoroethylene

ΐ ..ft-

f with an outside diameter of 1.65 mm was arranged in each of the four- ami v * s of the piston in order to achieve the best possible radial guidance.

to enable and Eelbun | $ glsiättsee and undesirable, radial

Would it found that due to d # r above measures safe and proper operation in any position isiö ^ I WAt. The measurement of the test results, however, took place in the gravity opening position of the valve. The valve was then connected to a control circuit according to FIG. 26 of the drawing, which was provided with the following elements.

909821/0454

part Reference number specification resistance P. 100 k Q ¹ resistance 368 2.2k Q resistance 369 47 Q Resistance. 375 10 k α resistance 378 50 k Ö resistance
Potentiometer in line 357 between
between the diodes 355
and 379
372 ' 3.5 k Q
10 k Q 10 turns capacitor 370 0.1 mfd., 200V diode 353 . 1 N 1695 diode 354 1 N 1605 diode 355 1 N 1685 diode 356 IN 1695 diode 363 1 N 1695 PNP transistor 372 2 N 3250 transistor 364 2 N 1671 controlled equal
judge 360 2 N 1597 Zener diode 379 IN 1779, 22V Transformer for
constant tension Sola cut. No. 23-13-
060, UO V change

tension

909821/0454

The flow harassment around SfctuerveüSlfiis A * became "bti conitgmtem SStalaÖdruefe fe" §ümmi, JMs BareMftiS amount was lengthened as a function of the VuUnUomai * ?? * Mm% HIr two different pressure diferenitöEe; of the valve fixed. Ber arsle IMfferenadruck was 0.91 ϊφ / cm, the width 1.4 kp / sm. Bie Fotentiomefstellung, the »f jfl dlrt & t au! the Stiuefepa ^ niii ^ is viewed as a function of the Durchfiu & ** te bnHMogßsithmimh auigstragea. Me graphic in this regard

d from Figure 34 to Zsicämimg © rsicfetlich. Di ^ Vere true lnnerMb sin * s regions of * 0, OEf mm re-ι ?. The dynamic range of the venues was greater than 100. All of the curve of the papillic oa? Itation was made with a con " ΜΜ * $ άτψζΙι van C, 33 kp / cm öralelf, the lower curve with inlae pressure? Of I ₅ 4 fep / cm.

909821/0454

Claims (11)

Claims 1. Method for controlling the actuator of a control device, in particular a solenoid valve, by means of an excitation current a restoring force on the actuator in the direction of an end division and the magnetic force of the solenoid towards the other End position acts, characterized in that on the one hand the maximum value of the time-variable magnetic force is greater than the restoring force and the mean value of the time-varying magnetic force is smaller than the restoring force or that the minimum value of the time-changing Magnetic force smaller than the restoring force and the mean value of the time-varying magnetic force greater than the restoring force is. 2. The method according to claim 1, characterized in that the time variable magnetic force is applied to the actuator in the form of a pulse sequence, the amplitude and / or the width and / or the distance between the pulses can be controlled as a function of a measured variable. U eue documents ιαπ.7Ιιαι * .2Νγ, ι 2701 BATH ORIGINAL 909821 / 045-4 3. The method according to claims 1 or 2, characterized in that by switching on a diaphragm or constriction (60) in the exit of the j control device a differential pressure force is generated, which is ! equal to the other forces when the exit is not narrowed. 4. The method according to claim 1 or 2, characterized in that the Bssrsich the axial movement of the actuator is controlled. 5. The method according to claim 1 or 2, characterized in that for ■ Suppression of rebound vibrations of the actuator from one Valve seat (237, 289) controllable radial vibrations of the actuator be generated. 6. Hegel device for carrying out the method according to one or several of claims 1 to 5, wherein in a housing between two end positions movable actuator is arranged by the Magnetic force of a magnetic coil and at least one restoring force counteracting this magnetic force is applied, characterized in that that in one of the two end positions designed as a stop per se known seat is provided and that the solenoid with a Pulse supplying circuit (C) is connected. 909821/0454 7. Control device according to claim 6, characterized in that the Circuit (C) a controllable as a function of a measured variable, the Has pulse generating device, the amplitude and / or the width and / or the spacing of the pulses can be controlled, 8. Control device according to claim 0 or 7, characterized in that that the control device has an outlet with a diaphragm or Constriction (60) is provided. 9. Control device according to one or more of the preceding claims 6 to 8, characterized in that the valve seat (237) and the actuator have a conical surface which can be fitted into one another. 10. Control device according to one or more of the preceding claims 6 to 8, characterized in that the valve seat (289) is conical and that a ball (291) between the valve seat and the Actuator is arranged. 11. Control device according to one or more of the preceding claims β to 10, characterized in that the actuator is known per se Way is surrounded by at least one flexible ring (131, 132) which is in contact with the inner wall of the housing. ²⁷⁰¹ 900821 / Q4B4