The technological development of pneumatic actuators is becoming more and more mature

With the wide application of pneumatic valves, the technology of pneumatic actuators is getting better and better, the gap between domestic pneumatic actuators and imported pneumatic actuators is getting smaller and smaller, and the types are more and more. Now the pneumatic actuator inspection method is described as follows:

1) Calibration preparation and appearance inspection

1. All test instruments must be energized and preheated 30 minutes in advance;

2, the test air source pressure should meet, 0.6±0.1Mpa;

3. The appearance of the actuator has no obvious damage, and the gas-guiding copper pipe has no obvious dented marks and is firmly assembled;

4. The length of the connecting screw of the position transmitter must meet the technical requirements of the inspected actuator model; The plane formed by the connecting rod and the connecting screw fastened on the transmitter shaft should be perpendicular to the horizontal plane;

2) Inspection standards and methods

1. Fix the pneumatic actuator on the check table, and connect the air source, control air source and displacement detection connecting rod respectively; Calibrate the instrument on the test bench accurately;

2, mechanical zero calibration: input 4mA current signal (0%), control gas signal should be 0.02Mpa, at this time the cylinder piston stroke should be zero; If it is not zero, the zero can be adjusted by adjusting the nut on the zero adjusting screw (the zero is higher than the tight nut); Zero point and range need to be adjusted repeatedly; Zero error should be less than 1%;

3, mechanical full scale calibration: input 20mA current signal (100%), control gas signal should be 0.10Mpa, at this time the cylinder piston stroke should be the upper limit; If it is not the upper limit value, the range can be adjusted by adjusting the tightness of the range tension spring (the range is small, the range is large, the tension spring); Zero point and range need to be adjusted repeatedly; The full scale error should be less than 1%;

4, mechanical range midpoint positioning: after the zero and range alignment, input 12mA current signal (50%, 0.06Mpa), adjust the position of the transmitter connection rod, so that it should be kept perpendicular to the horizontal plane at the point;

5, full stroke deviation calibration: The input control gas signal is 0.02Mpa (0%), and then gradually increase the input signal 0.036, Mpa (20%), 0.052, Mpa (20%), 0.068, Mpa (60%), 0.084, Mpa (80%), 0.1, Mpa (100%), so that the cylinder piston goes the full stroke. The deviation of each point should be ≤1.5%;