Wholesale customization of ZH series pneumatic actuators
Working principle of pneumatic actuator with regulating valve
The intelligent display is an instrument used to monitor the working state of the valve and the work during the execution of the pneumatic control valve. Two position sensors are used to monitor the working state of the valve, judge whether the pneumatic control valve is in the open or closed state of the valve, and record the number of valve switches through programming. There are two 4~20 corresponding to the valve open mA output and two foot normally open and normally closed output contacts. These output signals are used to control the opening and closing of the valve. According to the requirements of the system, the intelligent valve display instrument can be divided into three parts in terms of hardware: analog part, digital part and key/display part.
The analog circuit of pneumatic actuator with regulating valve mainly includes power supply, analog input circuit and analog output circuit.
The power supply part supplies energy for the whole circuit, including analog circuit, digital circuit and display. In order to realize the remote control of valve opening and reading, it is necessary to transmit the valve opening information to other control instruments. At the same time, the control instrument can open the valve from a distance to a certain extent. The system requires 1 channel of 4~20mA analog input signal and 1~2 channels of 4~20mA analog output signal. The analog input signal is converted into a digital signal corresponding to the valve opening through A/D conversion and sent to the microcontroller of the digital part, which can be output after filtering. The valve opening information D/A is converted into analog signal output for connecting and displaying the valve opening or other control equipment. In this design system, all digital data are serial input and output. In order to save chip resources and space, 4~20mA is input. When the analog quantity is converted to digital quantity, the existing 4-way DA chip is used to combine with the system resources of the microcontroller, and 8-bit cooperative AD is used.
The control mode of pneumatic actuator equipped with regulating valve uses the characteristics of compressed air to push the combined motion of multiple groups of pneumatic pistons in the actuator, transfer the force to the beam and internal curve track, drive the hollow spindle to rotate, deliver the compressed air disk to each cylinder, change the inlet and outlet positions, change the rotation direction of the spindle, and adjust the number of cylinder combinations, And drive the load (valve) according to the rotation torque required by the load (valve). Two five way solenoid valves are usually used together with the double acting pneumatic actuator, and two positions are controllable: switch, five ways have five channels for ventilation, one is connected to the air source, two are connected to the inlet and outlet of the outer air chamber, and two are connected to the inlet and outlet of the inner air chamber. The specific working principle can refer to the working principle of the double acting pneumatic actuator.
