CN113110627B - An adjustable venturi with high precision, high reliability and fast response - Google Patents

Abstract

The present application relates to the field of aerospace technology, in particular to an adjustable venturi with high precision, high reliability and fast response. An adjustable venturi with high precision, high reliability and quick response, comprising a venturi body, the venturi body has an inlet end, an outlet end and a flow channel for connecting the inlet end and the outlet end, and the flow channel includes sequential connections It also includes an adjustment member, an electric cylinder and a control unit; the adjustment member has a fixed part and an adjustment part, the fixed part is connected with the output shaft of the electric cylinder, the adjustment part has a conical structure, and the adjustment part is located in the In the flow channel, and can form a critical flow channel with the transition section; the control unit is electrically connected with the electric cylinder; in this application, the control unit controls the electric cylinder to make the adjustment part move along the axis of the flow channel in the flow channel to change the critical flow. The cross-sectional area of the runner. The use of an electric cylinder improves the accurate adjustment of the position, state and orientation of the adjustment member.

Description

An adjustable venturi with high precision, high reliability and fast response

technical field

The present application relates to the field of aerospace technology, in particular to an adjustable venturi with high precision, high reliability and fast response.

Background technique

The existing adjustable cavitation venturi usually has a circular cross-section. The minimum flow cross-sectional area at the throat is adjusted through the cooperation of the movable spool with the constricted section, the throat and the expansion section, so as to achieve the purpose of regulating the flow. .

The existing valve core is controlled by a common motor, and there will be errors in the actual displacement of the valve core, which makes the actual flow cross-sectional area inconsistent with the theoretical flow cross-sectional area, resulting in low accuracy of flow adjustment.

SUMMARY OF THE INVENTION

The purpose of the present application is to provide an adjustable venturi with high precision, high reliability and fast response, to a certain extent, to solve the problem that the valve stem is controlled by an ordinary motor in the prior art, so that the accuracy of the flow adjustment is not high. technical issues.

The present application provides an adjustable venturi with high precision, high reliability and rapid response, including a venturi body, the venturi body has an inlet end, an outlet end, and a venturi for communicating the inlet end and the outlet a flow channel at the end, the flow channel includes a constriction section, a transition section and an expansion section connected in sequence; also includes an adjustment member, an electric cylinder and a control unit;

The adjustment member has a fixed part and an adjustment part, the fixed part is connected with the output shaft of the electric cylinder, the adjustment part has a conical structure, the adjustment part is located in the flow channel, and can be connected with the transition A critical flow channel is formed between the segments; the control unit is electrically connected with the electric cylinder;

The control unit controls the electric cylinder to make the adjustment part move along the axis of the flow channel in the flow channel, so as to change the cross-sectional area of the critical flow channel.

In the above technical solution, further, the electric cylinder includes a servo motor, a motor housing and a ball screw;

The motor housing has an accommodating space, the servo motor and the ball screw are located in the accommodating space, the ball screw is connected with the output shaft of the servo motor, and the fixing part is sleeved in the accommodating space. on the ball screw;

The servo motor is electrically connected to the control unit.

In the above technical solution, further, the control unit includes a PLC controller, a servo motor controller and a servo motor encoder electrically connected to the PLC controller;

the servo motor controller is electrically connected to the servo motor, the receiving end of the servo motor encoder is electrically connected to the servo motor, and the transmitting end is electrically connected to the servo motor controller;

The PLC controller can transmit a preset command signal to the servo motor controller, and the servo motor controller that receives the preset command signal is used to control the movement of the servo motor, so that the adjustment member moves along all the directions. The axis direction of the flow channel moves;

The servo motor encoder is used for recording operation speed data and rotation direction data of the output shaft of the servo motor, and can feed back the operation speed data and the rotation direction data to the servo motor controller.

In the above technical solution, further, a reset member is further included, and the reset member is electrically connected to the PLC controller;

The reset member includes a magnetic ring and at least three magnetic limit switches arranged on the motor housing at intervals, and the vertical plane where the magnetic limit switches close to the main body of the venturi are located is the origin position;

the magnetic ring is arranged on the fixing part;

When the fixed part moves along the axis, the magnetic ring will trigger different actions of the magnetic limit switch, and the PLC controller can receive the action signal of the magnetic limit switch, and according to the The action signal transmits a preset command signal to the servo motor controller, so as to reset the fixed part to the indicated origin position.

In the above technical solution, further, three magnetic limit switches are provided, and the three magnetic limit switches are respectively an upper limit magnetic switch, a warning magnetic limit switch and a lower limit magnetic switch;

The warning magnetic limit switch is arranged between the upper limit magnetic switch and the lower limit magnetic switch; the lower limit magnetic switch corresponds to the origin position;

The servo motor controller can respectively control the servo motor to move at a first speed and a first rotation direction to move the magnetic ring toward the upper limit magnetic switch, the servo motor to move at the first speed and a first rotation direction, respectively. Two rotational directions move the magnet ring toward the warning magnetic limit switch and the servo motor moves at a second speed and the second rotational direction to move the magnet ring toward the lower limit magnetic switch , when the magnetic ring moves to the origin position, the fixing part is reset.

In the above technical solution, further, the reset member further includes a limit block disposed between the electric cylinder and the venturi body;

A first conducting portion, a second conducting portion and a third conducting portion are sequentially opened in the interior of the limiting block from the end close to the electric cylinder to the end close to the venturi body. The third conducting portion communicates with the flow channel;

the first conducting portion, the second conducting portion and the third conducting portion are stepped;

The regulating portion passes through the first conducting portion, the second conducting portion and the third conducting portion in sequence, and extends into the flow channel;

The second conducting portion is adapted to the fixing portion, and the second conducting portion can limit the position of the fixing portion.

In the above technical solution, further, the adjustment member includes a valve stem;

The valve rod is formed with the fixing part at the connection with the electric cylinder, and the part of the valve rod located in the flow channel is formed as the regulating part;

A protective layer is provided on the outer side wall of the valve stem and the inner side wall of the flow channel;

The protective layer is formed of a polymer composite material.

In the above technical solution, further, there is a first sealing member between the regulating portion and the third conducting portion.

In the above technical solution, further, an outlet pipe joint is provided at the outlet end, and a second seal is provided between the outlet pipe joint and the inner side wall of the casing of the venturi main body.

In the above technical solution, further, a third sealing member is provided between the outlet pipe joint and the end of the casing of the venturi.

Compared with the prior art, the beneficial effects of the present application are:

An adjustable venturi tube with high precision, high reliability and rapid response provided by the present application includes a venturi tube body, and the venturi tube body has an inlet end, an outlet end, and is used for connecting the inlet end and the outlet port. a flow channel at the end, the flow channel includes a constriction section, a transition section and an expansion section connected in sequence; also includes an adjustment member, an electric cylinder and a control unit;

The adjustment member has a fixed part and an adjustment part, the fixed part is connected with the output shaft of the electric cylinder, the adjustment part has a conical structure, the adjustment part is located in the flow channel, and can be connected with the transition A critical flow channel is formed between the segments; the control unit is electrically connected with the electric cylinder;

The control unit controls the electric cylinder to make the adjustment part move along the axis of the flow channel in the flow channel, so as to change the cross-sectional area of the critical flow channel.

Specifically, the electric cylinder is a modular product that integrates a servo motor and a ball screw. It can convert the rotary motion of the servo motor into linear motion, and use the servo motor to improve the accuracy of the position, state and orientation of the adjustment member. adjust.

Description of drawings

In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the accompanying drawings that need to be used in the description of the specific embodiments or the prior art will be briefly introduced below. The drawings are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

1 is a schematic structural diagram of an adjustable venturi with high precision, high reliability and fast response provided in Embodiment 1 of the present application;

2 is a cross-sectional view of a high-precision, high-reliability, and fast-response adjustable venturi provided in Embodiment 1 of the present application;

3 is a cross-sectional view of an adjustable venturi with high precision, high reliability and fast response provided in Embodiment 2 of the present application;

4 is a top view of a high-precision, high-reliability, and fast-response adjustable venturi provided in Embodiment 2 of the present application;

FIG. 5 is a cross-sectional view of an adjustable venturi with high precision, high reliability and fast response according to the third embodiment of the present application.

In the figure: 100-venturi body; 101-inlet end; 102-outlet end; 103-flow channel; 104-contraction section; 105-transition section; 106-expansion section; 107-adjustment member; 108-electric cylinder; 109-fixed part; 110-adjustment part; 111-critical flow channel; 112-motor housing; 113-slot; 114-ball screw; 115-reset member; 116-upper limit magnetic switch; 117-warning magnetic limit Position switch; 118-lower limit magnetic switch; 119-first rotation direction; 120-second rotation direction; 121-limit block; 122-first conduction part; 123-second conduction part; 124-third 125-valve stem; 126-first seal; 127-outlet pipe joint; 128-second seal; 129-third seal; 130-connector.

Detailed ways

The technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

In the description of this application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation or a specific orientation. construction and operation, and therefore should not be construed as limitations on this application. Furthermore, the terms "first", "second", and "third" are used for descriptive purposes only and should not be construed to indicate or imply relative importance.

In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood in specific situations.

Example 1

1 and 2 , the present application provides an adjustable venturi with high precision, high reliability and rapid response, including a venturi body 100 , the venturi body 100 has an inlet end 101 and an outlet end 102 and a flow channel 103 for communicating the inlet end 101 and the outlet end 102, the flow channel 103 includes a constriction section 104, a transition section 105 and an expansion section 106 connected in sequence; it also includes an adjustment member 107, an electric cylinder 108 and the control unit;

The adjusting member 107 has a fixing portion 109 and an adjusting portion 110 , the fixing portion 109 is connected with the output shaft of the electric cylinder 108 , the adjusting portion 110 has a tapered structure, and the adjusting portion 110 is located in the flow channel 103, and can form a critical flow channel 111 with the transition section 105; the control unit is electrically connected to the electric cylinder 108;

The control unit controls the electric cylinder 108 to make the adjustment part 110 move along the axis of the flow channel 103 in the flow channel 103 to change the cross-sectional area of the critical flow channel 111 .

Specifically, the electric cylinder 108 is a modular product integrating the servo motor and the ball screw 114 , which can convert the rotary motion of the servo motor into linear motion, and use the servo motor to improve the control accuracy of the adjusting member 107 .

More specifically, the electric cylinder 108 includes a servo motor, a motor housing 112 and a ball screw 114; the motor housing 112 has a accommodating space, and the servo motor and the ball screw 114 are located in the In the accommodating space, the ball screw 114 is connected with the output shaft of the servo motor, and the fixing portion 109 is sleeved on the ball screw 114; the servo motor is electrically connected with the control unit.

In the actual working process, the present application can use the Delta servo control system to control the electric cylinder 108, thereby realizing accurate adjustment of the position, state and orientation of the adjustment member 107, wherein the Delta servo control system is an existing existing There are technologies, which are briefly described here: Delta's servo control system mainly relies on pulses for positioning. When the servo motor receives 1 pulse, it will rotate the angle corresponding to 1 pulse, thereby realizing the displacement of the ball screw 114; further Therefore, a closed-loop system can be formed between the pulses received by the servo motor and the pulses fed back by the servo motor, so as to precisely control the rotation of the servo motor, and then realize the accurate adjustment of the adjustment member 107. Usually, the adjustment accuracy can reach 0.0002mm, and the maximum The accuracy can reach 0.0125mm; at the same time, the servo motor can also achieve fast response, and the adjustment speed can reach 100mm/s.

In this embodiment, the control unit includes a PLC controller, a servo motor controller electrically connected to the PLC controller, and a servo motor encoder; the servo motor controller is electrically connected to the servo motor, and the servo motor controller is electrically connected to the servo motor. The receiving end of the servo motor encoder is electrically connected with the servo motor, and the transmitting end is electrically connected with the servo motor controller;

The PLC controller can transmit a preset command signal to the servo motor controller, and the servo motor controller that receives the preset command signal is used to control the movement of the servo motor, so that the adjustment member 107 moves along the movement direction. The axial direction of the flow channel 103 moves;

The servo motor encoder is used for recording operation speed data and rotation direction data of the output shaft of the servo motor, and can feed back the operation speed data and the rotation direction data to the servo motor controller.

In the actual working process, the PLC controller transmits a preset command signal to the servo motor controller. The preset command signal here refers to the pulse command. After the servo motor controller receives the pulse command, it drives the servo motor according to the corresponding The speed and direction rotate, and the rotary motion of the servo motor is converted into the linear motion of the adjustment mechanism through the transmission mechanism and the ball screw 114 . Specific steps are as follows:

Step 100: Calculate the number of pulses that the PLC controller needs to transmit when a certain liquid flow rate needs to be adjusted, for example, when a certain liquid flow rate needs to be increased, that is, when a certain liquid flow rate needs to be increased. The cross-sectional area of the large critical flow channel 111 can be used to calculate the moving distance of the adjustment part 110 through the relevant calculation formula of the venturi, and then calculate the angle that the servo motor needs to rotate through the transmission ratio of the transmission mechanism, the pitch of the ball screw 114, etc. Or the number of turns; then convert the angle of rotation into the number of pulses that the corresponding servo motor driver needs to send, and finally convert the number of pulses from the servo motor driver to the number of pulses that the PLC controller needs to send through the conversion of the electronic gear ratio.

Step 200: The PLC controller sends a preset number of pulses, and the adjustment part 110 moves, thereby adjusting the cross-sectional area of the critical flow channel 111 and adjusting the flow rate of the liquid flow; after the servo motor controller receives the pulse frequency and pulse number of the PLC controller , the servo motor driver sends a certain number of pulses at the corresponding pulse frequency, the servo motor receives the pulse frequency and the number of pulses (wherein, the pulse frequency corresponds to the rotation speed of the servo motor, and the number of pulses corresponds to the angle of rotation of the servo motor), the servo motor will be The speed corresponding to the pulse frequency rotates by the corresponding angle. At this time, the rotation of the servo motor will be recorded by the servo motor encoder, and the encoder will feed back the recorded pulses to the servo motor driver; in this way, the servo motor driver and the servo motor encoder Since the pulse of the servo motor encoder matches the pulse of the rotation angle of the servo motor, it is equivalent to forming a closed-loop control between the servo motor driver and the servo motor.

In summary, the formed servo drive system is a closed-loop control red copper, the servo motor driver can directly sample the encoder feedback signal of the servo motor, and a position loop and a speed loop are formed inside, which can overcome the existing problems of using open-loop stepper motors. The phenomenon of missing pulses, the present application makes the control performance more stable and reliable.

Embodiment 2

The second embodiment is an improvement on the basis of the foregoing embodiment, and the technical contents disclosed in the foregoing embodiment are not described repeatedly, and the content disclosed in the foregoing embodiment also belongs to the content disclosed in the second embodiment.

In this embodiment, as shown in FIG. 3 and FIG. 4 , when the flow rate of the first liquid is regulated, the venturi needs to be reset to facilitate the next use. For this problem, the present application also includes a reset member 115, the reset member 115 is electrically connected with the PLC controller;

The reset member 115 includes a magnetic ring and at least three magnetic limit switches arranged on the motor housing 112 at intervals. The position switch is arranged in the slot 113, and the magnetic ring is arranged on the fixing portion 109;

In the actual use process, the vertical plane where the magnetic limit switch close to the venturi body 100 is located is defined as the origin position; when the fixed part 109 moves along the axis direction, the magnetic ring will trigger Different magnetic limit switch actions, the PLC controller can receive the action signal of the magnetic limit switch, and transmit a preset command signal to the servo motor controller according to the action signal, so that the The fixing portion 109 is reset to the shown origin position.

Specifically, taking three magnetic limit switches as an example, the three magnetic limit switches are respectively an upper limit magnetic switch 116 , a warning magnetic limit switch 117 and a lower limit magnetic switch 118 ; The limit switch 117 is disposed between the upper limit magnetic switch 116 and the lower limit magnetic switch 118 ; the lower limit magnetic switch 118 corresponds to the origin position.

Specifically, when the magnetic ring moves to the vicinity of the magnetic limit switch, the magnetic field strength here increases, and the magnetic limit switch is closed by the action of magnetism; when the magnetic ring moves away from the magnetic limit switch, the magnetic field strength decreases, and the magnetic limit switch disconnect.

More specifically, when the current task execution ends or a reset instruction is received, the adjusting part 110 starts to rotate at the first speed (the first speed is a constant speed) and the first rotation direction 119 (the first rotation direction 119 is the clockwise rotation direction) ) to the upper limit magnetic switch 116, when the magnetic ring hits the upper limit magnetic switch 116, the adjusting part 110 stops moving and moves at the first speed and the second rotation direction 120 (the second rotation direction 120 is the counterclockwise rotation direction) , until the magnetic ring touches the warning magnetic limit switch 117, and when the warning magnetic limit switch 117 is closed, the adjusting part 110 lowers the magnetic limit at the second speed (the second speed is a constant speed, and the second speed is lower than the first speed) The switch 118 moves closer until it hits the lower limit magnetic switch 118, and the adjusting part 110 stops moving, and at this time the fixing part 109 also reaches the origin position.

To sum up, in the first aspect, since the magnetic switch 118 moves downward at a constant low speed every time it is reset to the origin position, the reset accuracy of the fixed part 109 can be improved, thereby facilitating the flow control of the venturi; On the other hand, it is possible to detect whether the three magnetic limit switches work normally each time the reset to the origin position. If the PLC controller does not receive the feedback signal from the magnetic limit switches when the fixed part 109 moves to the corresponding position, it means that the magnetic There is a problem with the limit switch, the fixed part 109 stops moving, and the PLC control controller reports an error; thirdly, the upper limit magnetic switch 116 and the lower limit magnetic switch 118 can limit the displacement of the fixed part 109. During normal operation, if the magnetic ring touches When the upper limit magnetic switch 116 or the lower limit magnetic switch 118 is reached, the fixed part 109 will stop moving, so that the fixed part 109 can only move within a certain range, which protects the servo motor and increases safety.

In this embodiment, in order to prevent the fixing part 109 from hitting the venturi body 100 during the movement, the reset member 115 further includes a limiter disposed between the electric cylinder 108 and the venturi body 100 . Position block 121; a first conducting portion 122 and a second conducting portion 123 are sequentially opened inside the limiting block 121 from the end close to the electric cylinder 108 to the end close to the venturi body 100 and a third conducting portion 124, the third conducting portion 124 communicates with the flow channel 103;

Specifically, the limiting block 121 is connected to the motor housing 112 by a connector 130 .

The first conducting portion 122 , the second conducting portion 123 and the third conducting portion 124 are stepped; the regulating portion 110 passes through the first conducting portion 122 and the second conducting portion in sequence. 123 and the third conducting portion 124, and extend into the flow channel 103; the second conducting portion 123 is adapted to the fixing portion 109. In the actual application process, when the fixing portion 109 completely touches the When connected to the second conducting portion 123 , the fixing portion 109 cannot move, so as to realize the limiting effect on the fixing portion 109 and ensure the safety of the venturi.

Embodiment 3

The third embodiment is an improvement on the basis of the above-mentioned embodiments, and the technical contents disclosed in the above-mentioned embodiments are not described repeatedly, and the contents disclosed in the above-mentioned embodiments also belong to the contents disclosed in the third embodiment.

In this embodiment, as shown in FIG. 5 , the regulating member 107 includes a valve rod 125 ; the valve rod 125 is formed with the fixing portion 109 at the connection with the electric cylinder 108 and is located in the flow channel Part of the valve stem 125 in 103 is formed as the adjustment part 110; in order to improve the reliability of the present application, a protective layer is provided on the outer side wall of the valve stem 125 and the inner side wall of the flow channel 103; The protective layer is formed of a polymer composite material.

Specifically, the polymer composite material is formed by the composite combination of various materials such as high molecular polymer, ceramic powder and carbon fiber. Preferably, the polymer composite material adopts KN22 polymer ceramic polymer material, which is prepared by grinding and fine filtration of polyurethane resin, modified epoxy resin, anti-rust paint and additives.

When spraying the polymer composite material on the outer side wall of the valve stem 125 and the inner side wall of the flow channel 103, the following process is used: firstly prepare the polymer composite material; The inner sidewalls are ground; final air spraying and high temperature curing.

Specifically, in order to better combine the protective layer with the outer sidewall of the valve stem 125 and the inner sidewall of the flow channel 103 , the outer sidewall of the valve stem 125 and the inner sidewall of the flow channel 103 are polished to Ra1 .6.

Specifically, the polymer composite materials are blended uniformly according to the corresponding ratio, and sufficient stirring is required to ensure uniform mixing.

Specifically, air spraying is a spraying method that uses compressed air to atomize paint. Here, it is necessary to reasonably adjust the spray shape (circle or fan shape) and spray width (size of fan shape) of the spray gun to ensure that the outer wall of the valve stem 125 and the flow The inner sidewall of the channel 103 can be uniformly coated, and the coating can be applied several times to ensure that the coating reaches an appropriate thickness.

Specifically, the high-temperature curing refers to placing the valve stem 125 and the venturi body 100 in a high-temperature container for heating and curing, preferably, heating at 80 degrees Celsius for more than 2 hours.

To sum up, in the first aspect, the special molecular structure of the polymer composite material endows the outer side wall of the valve stem 125 and the inner side wall of the flow channel 103 with high elasticity, so that the valve stem 125 and the flow channel 103 can adapt to temperature changes. Second, polymer composite materials have shock absorption and wear resistance, and can resist wear, erosion and other working conditions in most environments; third, polymer composite materials have excellent anti-corrosion properties and can Resist the corrosion of most low-temperature organic acids and inorganic acids, which can greatly extend the service life of the valve stem 125 and the flow channel 103. Specifically, its high-density molecular weight and smooth surface not only improve the anti-cavitation ability, but also improve the fluidity. The stability of the flow makes the flow regulation more controllable; in the fourth aspect, the valve stem 125 and the flow channel 103 with a protective layer can also be compatible with more corrosive fluids in the actual working process, such as High and low concentrations of sulfuric acid are also compatible, increasing reliability.

In this embodiment, in order to prevent the liquid from leaking from the gap between the third conducting part 124 and the adjusting part 110 , there is a first Seal 126 .

In this embodiment, an outlet pipe joint 127 is provided at the outlet end 102. In order to prevent liquid leakage from the gap between the outlet pipe joint 127 shown and the casing of the venturi body 100, the outlet pipe joint is A second seal 128 is provided between 127 and the inner side wall of the housing of the venturi body 100; a third seal is provided between the outlet pipe joint 127 and the end of the venturi housing Piece 129.

Specifically, the third sealing member 129 is an aluminum gasket, and the aluminum gasket forms a pre-tightening force between the outlet pipe joint 127 and the casing of the venturi, and the aluminum gasket plays a role of fastening and stability.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present application. scope. Furthermore, those skilled in the art will appreciate that although some of the embodiments herein include certain features, but not others, included in other embodiments, that combinations of features of different embodiments are intended to be within the scope of this application And form different embodiments.

Claims (7)

1. A high-precision high-reliability quick-response adjustable venturi comprises a venturi main body, wherein the venturi main body is provided with an inlet end, an outlet end and a flow passage for communicating the inlet end with the outlet end, and the flow passage comprises a contraction section, a transition section and an expansion section which are connected in sequence; the electric control device is characterized by further comprising an adjusting member, an electric cylinder and a control unit;

the adjusting component is provided with a fixing part and an adjusting part, the fixing part is connected with an output shaft of the electric cylinder, the adjusting part is of a conical structure, and the adjusting part is positioned in the flow channel and can form a critical flow channel with the transition section; the control unit is electrically connected with the electric cylinder;

the control unit controls the electric cylinder to enable the adjusting part to move in the flow channel along the axial direction of the flow channel so as to change the section area of the critical flow channel;

the electric cylinder comprises a servo motor, a motor shell and a ball screw;

the motor shell is internally provided with an accommodating space, the servo motor and the ball screw are positioned in the accommodating space, the ball screw is connected with an output shaft of the servo motor, and the fixing part is sleeved on the ball screw;

the servo motor is electrically connected with the control unit;

the control unit comprises a PLC controller, a servo motor controller and a servo motor encoder, wherein the servo motor controller is electrically connected with the PLC controller;

the servo motor controller is electrically connected with the servo motor, the receiving end of the servo motor encoder is electrically connected with the servo motor, and the transmitting end is electrically connected with the servo motor controller;

the PLC controller can transmit a preset instruction signal to the servo motor controller, and the servo motor controller which receives the preset instruction signal is used for controlling the servo motor to move so as to enable the adjusting component to move along the axial direction of the flow channel;

the servo motor encoder is used for recording the running speed data and the rotating direction data of the output shaft of the servo motor and feeding back the running speed data and the rotating direction data to the servo motor controller;

the adjustable venturi with high precision, high reliability and quick response further comprises a resetting component, and the resetting component is electrically connected with the PLC;

the reset component comprises a magnetic ring and at least three magnetic limit switches which are arranged on the motor shell at intervals, and the vertical plane where the magnetic limit switches close to the venturi tube main body are located is the original point position;

the magnetic ring is arranged on the fixing part;

when the fixing part moves along the axis direction, the magnetic ring can trigger different magnetic limit switches to act, the PLC can receive action signals of the magnetic limit switches and transmit preset command signals to the servo motor controller according to the action signals, so that the fixing part is reset to the original point position.

2. A high-precision high-reliability quick-response adjustable venturi tube according to claim 1, wherein three magnetic limit switches are provided, wherein the three magnetic limit switches are an upper limit magnetic switch, a warning magnetic limit switch and a lower limit magnetic switch;

the warning magnetic limit switch is arranged between the upper limit magnetic switch and the lower limit magnetic switch; the lower limit magnetic switch corresponds to the original point position;

the servo motor controller can respectively control the servo motor to move at a first speed and a first rotating direction so as to enable the magnetic ring to move towards the upper limit magnetic switch, the servo motor to move at the first speed and a second rotating direction so as to enable the magnetic ring to move towards the warning magnetic limit switch, and the servo motor to move at a second speed and the second rotating direction so as to enable the magnetic ring to move towards the lower limit magnetic switch, and when the magnetic ring moves to the original point position, the fixing part is reset.

3. A high accuracy high reliability quick response adjustable venturi according to claim 1, wherein said reset member further comprises a stopper disposed between said electric cylinder and said venturi body;

a first conduction part, a second conduction part and a third conduction part are sequentially arranged in the limiting block from the end part close to the electric cylinder to the end part close to the venturi tube main body, and the third conduction part is communicated with the flow channel;

the first conducting part, the second conducting part and the third conducting part are in a step shape;

the adjusting part sequentially penetrates through the first conduction part, the second conduction part and the third conduction part and extends into the flow channel;

the second conduction part is matched with the fixing part, and the second conduction part can limit the fixing part.

4. A high accuracy, high reliability and fast response adjustable venturi according to claim 1, wherein said adjusting member comprises a valve stem;

the valve rod is provided with the fixing part at the joint of the valve rod and the electric cylinder, and the part of the valve rod positioned in the flow passage is formed into the adjusting part;

protective layers are arranged on the outer side wall of the valve rod and the inner side wall of the flow passage;

the protective layer is made of polymer composite materials.

5. A highly accurate, reliable and fast responding adjustable venturi according to claim 3, wherein a first sealing member is provided between said adjusting portion and said third conducting portion.

6. A high accuracy, high reliability and fast response adjustable venturi according to claim 1, wherein an outlet pipe joint is provided at the outlet end, and a second sealing member is provided between the outlet pipe joint and the inner side wall of the housing of the venturi body.

7. A high accuracy high reliability fast response adjustable venturi according to claim 6, wherein a third seal is provided between said outlet conduit fitting and the end of the housing of said venturi.

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