US2160688A - Electric valve circuit - Google Patents

Description

May 30, 1939. w. H TEARE ET AL ELECTRIC VALVE CIRCUIT Filed Dec. 29, 1937 I t i:

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Patented May 30, 1939 UNITED STATES PATENT OFFICE ELECTRIC VALVE CIRCUIT Application December 29, 1937, Serial No. 182,290

13 Claims. (61. 250-27) Our invention relates to electric valve circuits, and more particularly to circuits for controlling electric valve apparatus.

Numerous circuits have been devised for the control of electric valve apparatus. Where the electric valve means is of the type employing an ionizable medium, such as a gas or a vapor, and which is providedwith a control member which initiates an arc discharge, it has become important to employ circuits which effect the desired control in a positive and reliable manner and which are not prohibitive from the standpoint Furthermore, it is desirable to provide control circuits which are inherently rugged in construction and arrangement and which do not require frequent inspection and replacement of parts. In addition, it is frequently desirable to employ control circuits which generate control voltages of predetermined wave form, such as voltages having a substantially perpendicular wave front which assure positive initiation of arc discharges within the electric valve means.

It is an object of our invention to provide a new and improved electric control circuit.

It is another object of our invention to provide a new and improved control circuit for electric valve apparatus.

It is a further object of our invention to provide a new and improved control circuit for electric valve apparatus of the type employing an ioniza: ble medium and havinga control member which initiates an arc discharge between the principal electrodes of the electric valve means.

It is a still further object 01 our invention to provide a new and improved control or excitation circuit for electric valve apparatus of the type employing an'ionizable medium and which includes an anode, a'cathode and a control member in proximity to the cathode which initiates an are discharge between the anode and cathode upon the application of a predetermined minimum potential across the control member and the cathode.

In accordance with the illustrated embodiment of our invention, we provide an improved control circuit for electric valve apparatus of the type employing an ionizable medium and which includes an anode, a cathode and a control member in proximity to the cathode for initiating an arc discharge to render the electric valve conductive. The electric valve means may be of the type requiring the application of a minimum critical potential across the control member and the cathode toeffect the initiation of a discharge between the control member and the cathode and, of

which is charged irom a direct current source.

Means such as a saturable inductive device is employed to establish a discharge between the control member and the cathode and hence to render the electric valve conductive. The satura- 10 ble inductive device includes a winding for producing an alternating voltage '0! peaked wave form and this winding is connected in series relation with the capacitance and the control member. The positive impulses of voltage of peaked wave 15 form, acting in conjunction with the voltage produced by the capacitance, are of suillcient magnitude to render the electric valve means conductive at a predetermined time during each positive half-cycle of applied anode-cathode voltage, or during a predetermined number of consecutive positive half cycles. The capacitance, the winding of the saturable inductive device and the control member are connected in series relation at all times. Suitable phase shifting means are provided to control the times during the positive halt cycles of applied anode-cathode voltage at which the electric valve means is rendered conductive.

For a better understanding of our invention, reference may be had to the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims. Fig. 1 or the accompanying drawing diagrammatically illustrates an embodie mentor our invention as applied to at bi-phase rectifier; Fig. 2 represents certain operating characteristics thereoi, and Fig. 3 diagrammatically illustrates an embodiment of our inventipn as applied to an electric welding circuit. 40

Referring now to Fig. 1 oi the accompanying drawing, we have diagrammatically illustrated our invention as applied to electric valve translating apparatus [or transmitting energy from an alternating current circuit l to a direct current 5 circuit 2 through a transformer I and electric valve means I and I. The electric valve means 4 and 5 are preiierably of the type employing an ionizable'medium, such as a gas or a vapor, and

:each includes an anode 8, a cathode I and a 50 control member 8. The electric valve means 4 and 5 may be or the type employing a control member, such as the control member 8, which is in proximity to the mercury pool cathode I, and

which requires the application of a minimum critical potential difference to initiate an are discharge therebetween. Of course, the establishment oi an arc discharge between the cathode l and the control member 9 initiates a main discharge between the anode 8 and cathode I to render the electric valve means conductive. While for the purpose of illustrating our invention we have chosen to show it as applied to an electric valve of this particular type, it is to be understood that our invention in its broader aspects applies to electric valve apparatus generally.

To energize control members 9 oi electric valve means 4 and 5, we provide a pair of excitation circuits 9 and I9 which are associated with electric valves 4 and 5, respectively. The excitation cir ts 9 and III are similar in construction and arrangement and in order to facilitate description thereof excitation circuit 9 associated with electric valve 4 will be considered in particular. The excitation circuit 9 is connected across cathode I and control member 9 oi the electric valve 4 and includes a capacitance Ii which is charged from any suitable direct current source II. The capacitance is charged so that the upper plate thereof is positive relative to the negative plate. As an agency for providing a source of unidirectional voltage, we employ any suitable arrangement such as a full wave rectifier l9 including a transformer i4 and a pair of unidirectional conducting devices or electric valves l5 and ii. The transformer 14 may be energized from any suitable source of alternating current and in the arrangement illustrated is shown as being connected to the alternating current circuit I. As an agency for applying a voltage of suitable wave form in series relation with the voltage of capacitance II to establish an arc discharge between cathode l and control member 8, we employ a saturable inductive device H. The saturable inductive device ll may comprise a core member i9 having a shunt magnetic path i9 and a restricted saturable path 29. A primary winding 2| is associated with the core member l9 and a secondary winding 22 is associated with the restricted saturabie portion 29 and produces a periodic or alternating voltage of peaked wave form having a substantially perpendicular wave front. The secondary winding 22 is connected in series relation with capacitance II and the control member 9 and the voltage generated thereby acts effectively in series relation with the unidirectional voltage appearing across the terminals of capacitance ii. The circuit including capacitance II and secondary winding 22 is complete at all times and the discharge of the capacitance H is eflected by the alternating voltage or peaked wave form generated by winding 221 While for the purpose oi! explaining our invention we have chosen to show the saturable inductive device I! as the agency for producing the voltage which eflects discharge oi the capacitance II, it is to be understood that we may employ any other conventional arrangement for producing a voltage or the required wave shape and magnitude.

As a means for controlling the time during each positive half cycle of applied anode-cathode voltage at which electric valves 4 and 5 are rendered conductive. we provide a circuit 29 which may include a transformer 24 and a suit able phase shifting arrangement such as a rotary phase shifter 25. By adjustment of the rotary phase shifter 25, the phase of the voltages impressed on primary windings 2i 0! the saturable inductive device II is controlled and in this The operation of the embodiment of our invention illustrated in Fig. 1 will be explained by considering the electric valve translating" apparatus when the system is transmitting unidirectional current to the direct current circuit 2 from the alternating current circuit I through transformer I and the electric valves 4 and 5. As will be well understood by those skilled in the art, the electric valves 4 and 5 conduct current alternately. Furthermore, it will be understood that the average voltage impressed on the direct current circuit 2 is maximum when the electric valves 4 and I are rendered conductive at the beginning of the positive half cycles of applied anode-cathode voltage, and that the average impressed on circuit 2 decreases as the electric valves are rendered conductive at later times during the half cycles. The capacitances II are charged to the polarity shown by means of the electric valves l5 and II and transformers II. The rectiiiers I! are designed so that the voltages appearing across the terminals of capacitances II are insumcient to establish an arc discharge between cathodes 'l and control members 9. In other words, the voltage of the capacitances H is less than the minimum voltage required to break down the auxiliary arc discharge between cathodes I and control members 9. The saturable inductive device i'l generates alternating voltages of peaked wave form in the secondary windings 22, and these voltages act in series relation with respect to the voltages produced by capacitances ll. During negative half cycles of the alternating voltage produced by secondary windings 22, the net voltage appearing across cathodes I and control members 9 is of course reduced so that an arc discharge is not initiated. However, during positive half cycles of the voltage of peaked wave form generated by the secondary windings 22, the voltage generated by these windings is in a direction to increase the voltage produced by capacitance ll so that the resultant voltage appearing across cathodes I and control members I exceeds the predetermined minimum voltage required to initiate an arc discharge therebetween. At the predetermined times established by the phase positions oi the voltages oi peaked wave form, the auxiliary arc discharge paths between cathodes I and control members I are broken down, eflecting a discharge of the capacitances ll through circuits including secondary windings 22, control members I and cathodes I. 0! course, main arc discharges will be established between the V anodes 9 ,and cathodes I substantially coincidentaliy with the establishment of the auxiliary arc discharges.

The operation of the embodiment ot'our invention shown in Pig. 1 may be better understood by referring to the operating characteristics shown in Pig. 2. Curve A represents the voltage of the alternating current circuit i and may represent the alternating voltage applied to one of the electric valves, such as the voltage applied across anode 9 and cathode I of electric valve 4. Curve B represents the voltage which must be applied between cathode I and control member 2 to initiate an arc discharge therebetween. Curve 0 represents the maximum voltage appearing across the capacitance Ii. Curve D represents the alternating voltage of peaked wave form generated by secondary winding 22 of the saturable inductive device I] in circuit 9. Curve E represents the resultant unidirectional voltages impressed on the direct current circuit when an inductive load is connected thereto.

It is to be understood that the voltage of the direct current circuit 2 may be controlled by adjustment of the rotary phase shifter 25. When the rotary phase shifter 25 is adjusted, the phase relation of the alternating voltages of peaked wave form generated by secondary windings 22 is controlled and thereby effects control of the conductivities of the electric valves 4 and 5.

In Fig. 3 there is diagrammatically illustrated another embodiment of our invention as applied to an electric valve system for energizing a welding circuit. The arrangement shown in Fig. 3 is similar in many respects to that of Fig. 1 and corresponding elements have been assigned like reference numerals. The electric valves 4 and 5 eifect energization of a welding circuit 26 through a transformer 21 having a primary winding 28 and a secondary winding 29.

As an agency for eflecting energization of the welding circuit 26 at a desired time, we provide a suitable circuit controlling means such as a switch 30 which permits energization of the control member 8 of electric valve 4. The switch 30 includes a movable contact SI and stationary contacts 32 and 33. When the movable contact I engages stationary contact 32, the capacitance II is charged to the polarity shown from the alternating current circuit I through transformer l4 and electric valves I5 and i6. When movable contact 3! is in the right-hand position to engage stationary contact 33, the secondary winding 22 of the saturable inductive device H is connected in series relation with the capacitance II and control member 8 to establish an auxiliary discharge between the control member 8 and cathode 1, thereby rendering the electric valve 4 conductive. The resistance 34 is connected in series relation with the control member 8 to control the rate at which the capacitance ll discharges. thereby controlling the interval of time during which the control member 8 is energized, or, in other words. controlling the number of halfcycles during which the electric valve 4 is rendered conductive.

In those applications where it ,is desired to transmit alternating current to the welding or load circuit 26, the electric valve 5 may be rendered conductive in response to the current conducted by the electric valve 4. We employ an alternating current circuit 85 including a transformer 36 having a primary winding 21 and a secondary winding 28 for effecting energization of the control member 8 in accordance with the current conducted by electric valve 4. Primary winding 31 is connected across primary winding 28 of transformer 21. A switch I! may be interposed between primary winding 31 and primary winding 2! as a means to permit selective control of the electric valve 5. so that a substantially unidirectional current or alternating current may be transmitted to the welding circuit 28. If desired, a suitable unidirectional conducting device 40 may be connected in series relation with the control member 8 of electric valve I so that only unidirectional current is supplied to the control member.

The operation of the embodiment of our invention shown in Fig. 3 is substantially the same as that explained above in connection with the arrangement of Fig. 1. If the switch 29 is moved to the open circuit position, electric valve 4 will transmit current to the load or welding circuit 28 through transformer 21. Of course, since only one electric valve is effective under these conditions, energy will be transmitted to circuit 26 during only half cycles of voltage of a predetermined polarity. If the switch 22 is in the closed position, and since the electric valve I is controlled in response to the current conducted by electric valve 4, the load circuit 20 will be energized during a positive half-cycle and a following negative half-cycle of voltage of circuit I or will be energized during a predetermined number of cycles of voltage of circuit l.

Referring more particularly to the operation of the control circuit associated with electric valve 4 when the movable contact 3| of the switch 30 is in the position shown in the figure, the capacitance ll will be charged to the polarity indicated. When the movable contact 3| is moved to the right-hand position to engage stationary contact 33, the alternating voltage of peaked wave form induced in secondary winding 22, acting in conjunction with the unidirectional voltage of capacitance II, will be sufficient to establish an arc discharge between control member 8 and cathode I. This discharge, of course,- will initiate an arc discharge between anode 6 and cathode 1, thereby rendering the electric valve conductive. Of course, the load circuit 26 will be energized during an interval of time corresponding to the period of conduction ofthe electric vaivc 4. If the switch 3! is in the open circuit position, the electric valve 5 will not be rendered conductive. If the switch 39 is in the closed circuit position, the electric valve 5 will follow the electric valve 4 so that the load circuit 28 is energized during a complete cycle of the voltage of circuit I. It is to be understood that the period of energization of the control member 8 of electric valve 4 may be controlled by the design of the circuit including the adjustable resistance 34. If the time constant of the circuit including capacitance ll, secondary winding 22 valve 4 will be rendered conductive during only one positive halt-cycle of applied anode-cathode voltage or during only a portion of one positive half-cycle or applied anode-cathode voltage depending upon the setting of the rotary phase shifter 25.. If the resistance 24 is adjusted so that the time constant of this circuit is relatively large, the discharge of the capacitance ll may be extended in the direction of the time axis so that the electric valve 4 is rendered conductive during an interval of time including more than one positive hali-cycleof anode-cathode voltage, eiiecting energization oi the load circuit 26 during a corresponding interval of time. Of course, when it is desired to eil'ect energizatlon of the load or welding circuit 26 during two half-cycles of voltage of circuit Lthe switch 39 may be moved to the closed circuit position so that electric valves 4 and 5 conduct current during a complete cycle. If, for example, it is desired to effect energization' of the load circuit 26 during four or six cycles, the switch 88 is maintained in the closed position and the resistance 34 is adjusted so that the discha'rge of the capacitance II is extended suiliciently to render the electric valve 4 conductive at the beginning of the proper number of consecutive positive half-cycles of anodecathode voltage.

tion as applied to a particular system or connections and-as embodying various devices diagrammatically shown, it will be obvious to those skilled in the art that changes and modifications may be made without departing from our invention, and we, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent oi the United States is:

1. In combination, a supply circuit, a load circuit, electric translating apparatus connected therebetween and including an electric valve of the type employing an ionizable medium and having an anode, a cathode and a control member for rendering said electric valve conductive, and a circuit connected across said control member and said cathode for establishing an electric discharge therebetween and comprising a capacitance, means for charging said capacitance and means connected in series relation with said capacitance and said control member for producing voltage to eflect discharge 0! said capacltance.

2. In combination, an alternating current sircuit, a load circuit, electric translating apparatus connected therebetween and including an electric valve of the type employing an ionizable medium and having an anode, a cathode and a control member in proximity to said cathode for initiating an arc discharge therebetween, and a circuit connected across said control member and said cathode for energizing said control member to render said electric valve conductive at a predetermined time during each positive half cycle of applied anode-cathode voltage and comprising a capacitance, means for charging said capacitance and means connected in series relation with said capacitance and said control member for producing a periodic voltage oi! peaked wave form for discharging said capacitance to initiate an arc discharge between said control member and said cathode.

3. In combination, a supply circuit, a load circuit, electric translating apparatus connected therebetween and including an electric valve of the type employing an 7 ionizable medium and having an anode, a cathode and a control member for rendering said electric valve conductive. and a circuit connected across said control member and said cathode for establishing an arc discharge therebetween and comprising a capacitance, means for charging said capacitance and an inductive device having a winding for producing an alternating voltage of peaked wave form for discharging said capacitance to initiate an arc discharge between said control member and said cathode, said winding being at all times connected in series relation with said capacitance and said control member.

4. In combination, an alternating current circuit, a load circuit, electric translating apparatus connected therebetween and including an eelctrlc valve oi the type employing an ionizable medium and having an anode, a cathode and a control member in proximity to said cathode for initiating an arc discharge therebetween, a circuit connected across said. control member and said cathode for energizing said control member to render said electric valve conductive at a predetermined time during each positive hall cycle of applied anode-cathode voltage and comprising a capacitance, means for charging said capacitance and means connected in series relation with said capacitance and said control member for producing a periodic voltage of peaked wave term for discharging said capacitance to initiate an arc discharge between said control member and said cathode, and means for controlling the phase oi' said periodic voltage relative to the voltage of said alternating current circuit. 7

5. In combination, an alternating current circuit, a load circuit, electric translating apparatus connected therebetween and including an electric valve of the type employing an ionizable medium and having an anode, a cathode and a control member in proximity to said cathode tor initiating an arc discharge therebetween, a circuit connected across said control member and said cathode tor energizing said control member to render said electric valve conductive at a predetermined time during each positive half cycle of applied anode-cathode voltage and comprising a capacitance, means for charging said capacitance and a saturable inductive device having a primary winding and a secondary winding connected in series relation with said capacitance and said control member for producing an alternating voltage oi peaked wave term to discharge said capacitance to initiate an arc discharge between said control member and said cathode, and means for controlling the energization of said p'rimary winding to control the time during each pofltive halt cycle of said alternating current circuit at which said electric valve is rendered conductive.

6. In combination, a supply circuit, a load circuit, electric translating apparatus connected therebetween and including an electric valve of the type employing an ionizable medium and having an anode, a cathode and a control member for rendering said electric valve conductive, and a circuit connected across said control member and said cathode tor establishing an are discharge therebetween and comprising a capacitance, means for charging said capacitance, means arranged to be connected in series relation with said capacitance and said control member for producing a voltage 01' suflicient magnitude which cooperating with the voltage of said capacitance is effective to discharge said capacitance through a circuit including said control member and said cathode and means for selectively connecting or disconnecting said capacitance in circuit with said control member.

7. In combination, 'a supply circuit, a load circuit, electric translating apparatus connected therebetween and including an electric valve of the type employing an ionizable medium and having an anode, a cathode and a control member for rendering said. electric valve conductive, and a circuit connected across said control member and said cathode for establishing an are discharge therebetween and comprising a capacitance, means for charging said capacitance, means arranged to be connected in series relation with said capacitance and said control member for producing a voltage of peaked wave form of sufllcient magnitude to eiiect discharge of said capacitance through a circuit including said control member and said cathode and switching means for connecting said capacitance in circuit with said last mentioned means and said control member to control the energizatlon oi said load circuit.

8. In combination, a supply circuit, a load circuit, electric translating apparatus connected therebetween including an electric valve means 1| of the type employing an ionizabie medium and having an anode, a cathode and a control mem- F ber for rendering said electric valve means conductive, and an excitation circuit connected across said control member and said cathode for establishing arc discharges therebetween to render said electric valve means conductive for a predetermined interval of time and comprising a capacitance, means for charging said capacitance, a resistance, means connected in series relation with said capacitance, said resistance and said control member for producing a voltage to eflect discharge of said capacitance through a circuit including said resistance, said control member and said cathode.

9. In combination, a supply circuit, a load circuit, electric translating apparatus connected therebetween and including an electric valve of the type employing an ionizable medium and having an anode, a cathode and a control member for rendering said electric valve conductive, a control circuit connected across said control member and said cathode for establishing arc discharges therebetween and comprising acapacitance, means for producing a periodic voltage of peaked wave form, means for charging said capacitance and means for selectively connecting said capacitance to said last mentioned means or to said control circuit to control the energization of said load circuit, and means for controlling the rate 01' discharge of said capacitance to control the period of energization of said load circuit.

10. In combination, a supply circuit, a load circuit, electric translating apparatus connected therebetween and including an electric valve of the type employing an ionizable medium and having an anode, a cathode and a control member for rendering said electric valve conductive, a control circuit connected across said control member and said cathode for establishing arc discharges therebetween and comprising a capacitance, means for producing a periodic voltage of peaked wave term, means for charging said capacitance and means for selectively connecting said capacitance to said last mentioned means so that the voltage of said capacitance and said periodic voltage act eflectively in series to discharge said capacitance through a circuit including said control member and said cathode to render said electric valve conductive, and means for controlling the rate or discharge of said capacitance to control the period of energiaation 01' said load circuit.

11. In combination. a supply circuit, a load circuit. electric translating apparatus connected therebetween and including an electric valve of the type employing an ionizabie medium and having an anode, a cathode and a control member for rendering said electric valve conductive, and a control circuit connected, across said control member and said cathode for rendering said electric valve conductive tor a predetermined portion of a single positive halt cycle of applied anodecathode voltage and comprising a capacitance, means for charging said capacitance, means for producing a voltage of peaked wave form which acting in conjunction with the voltage of said capacitance establishes an arc discharge between said cathode and said control member and means for connecting said capacitance in series relation with said last mentioned means and said control member to render said electric valve conductive.

12. In combination, a supply circuit, a load circuit, electric translating apparatus connected therebetween and including an electric valve of the type employing an ionizable medium and having an anode. a cathode and a control memher for rendering the electric valve conductive, a control circuit connected across said control member and said cathode for rendering said electric valve conductive for a predetermined interval of time and comprising a capacitance, means for said capacitance and means for producing a periodic voltage of peaked wave form which acting in conjunction with the voltage 0! said capacitance discharges said capacitance to establish an arc discharge between said cathode and said control member, and means for controlling the rate of discharge 01' said capacitance to render said electric valve conductive ima predetermined number of consecutive positive halt-cycles of applied anode-cathode voltage.

13. In combination, an alternating current supply circuit, a load circuit, electric translating apparatus connected therebetween and including an electric valve or the type employing an ionizabl medium and having an anode, a cathode a control member for rendering said electric valve conductive, and a circuit connected across said control member and said cathode tor establishing an arc discharge therebetween and comprising a capacitance, a rectifier energized from said alternating current supply circuit for charging said capacitance and means connected in series relation with said capacitance and said,

control member for producing a voltage to efl'ect discharge of said capacitance.

WILLIAM a. man. 01mm w. uvmas'ron.

CERTIFICATE OF CORRECTION. Patent No. 2,160,688. May 0, 19 9.

WILLIAM H. TEARE, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correctionss follows: Page 1, secand column, line 36, for the Word. "et read a; page 2, first column, line 21, strike out "the"; same page, second column, line 19, after "average" insert voltage; and that the said Letters Patent shouliibe read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 18th day of July, A. D. 1939.

Henry Van Aredsle (Seal) Acting Commissioner of Patents.

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