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2019

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What is the variable frequency of electric gate valve? How to control?

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There are many forms of valves. The simple one is a certain form of switch. The more complicated one is to control the opening of the electric gate valve baffle through simulation. The essence is to control the angle. This is the servo valve, which must be realized by servo control. It is rare to see the size of the valve controlled by the speed size. Of course, it is not to say that there is no such thing. I have seen it in the chemical fiber plant material system. In this form, the air blower maintains a constant wind pressure, which is equivalent to a positive pressure feed. There is a rotating roller in the middle. When the filling nozzle and the roller open the feeding hole, the material can come down and turn over, but the blockage cannot come down. As long as the motor rotates and there is more material, the feeding speed will be faster. This can be understood as speed control. Electric gate valve.

  There are many forms of valves. The simple one is a certain form of switch. The more complicated one is to control the opening of the electric gate valve baffle through simulation. The essence is to control the angle. This is the servo valve, which must be realized by servo control. It is rare to see the size of the valve controlled by the speed size. Of course, it is not to say that there is no such thing. I have seen it in the chemical fiber plant material system. In this form, the air blower maintains a constant wind pressure, which is equivalent to a positive pressure feed. There is a rotating roller in the middle. When the filling nozzle and the roller open the feeding hole, the material can come down and turn over, but the blockage cannot come down. As long as the motor rotates and there is more material, the feeding speed will be faster. This can be understood as speed control. Electric gate valve.

  1. The frequency converter speed regulation function, that is to say, can only make the car run faster, or run slowly, or even stop, but it cannot control the current position of the motor rotor. If the position of the servo valve is changed, only the servo system and frequency conversion can be used. The controller is not complete, and position and speed control are completely two concepts.

  2. If the speed is different, the output size of the valve will be different (essentially, the rotation frequency determines the flow rate). This time the valve can be controlled by an inverter. By adjusting the frequency of the inverter, the speed of the motor is changed, and then Control valve target value.

  3. The current control system is divided into two categories, one is open loop and the other is closed loop. The difference lies in the closed loop measurement and comparison processing and output with actual feedback. Therefore, closed loop control has high precision and is expensive, and the actuator part is compulsory. Switch control is relatively simple. As long as a certain value is given, approximately a value will be output. The inverter controls the speed, and often does not feedback with the encoder. It is usually used in relatively coarse situations to control valves. As long as you understand the valve motor as an ordinary asynchronous motor, adjust the frequency of the motor to change the speed of the motor, thereby controlling The "opening" size of the valve, such as simply wiring according to the inverter control motor wiring diagram, the user team considers different values ​​​​and how large is equivalent to the "opening" of the electric gate valve and the given frequency of the valve panel corresponding to the "opening" .

  4. In open-loop control situations, of course, the external terminal control of the inverter and the control valve given by the analog quantity can also be used. Naturally, it is the same as the external control of the motor by the ordinary inverter, but the external quantitative value, such as the size of the potentiometer, corresponds to Depending on the size of the motor speed, it is also the size of the valve "opening".

  5. If you want to use closed-loop control and need to measure the amount of feedback, such as a valve to control the temperature of the air flow to cool the object, as long as you add a temperature sensor, feedback to the inverter, use the function of the PID inverter, a simple single-loop closed loop , can meet the requirements. The lower the temperature, the PID output will be a little larger, but the higher the temperature, the PID output will be a little smaller, thereby achieving relatively accurate and stable temperature control. During the process, the valve will change in real time instead of " "On" for the purpose of temperature control. The same principle can also be applied to some aspects of flow and pressure control. Of course, if the PID function inside the inverter is not good or even has no PID function, you can use an external PID instrument or PLC to achieve it.

 Keywords in this article: Electric gate valve

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