Pneumatic actuators of several detection methods, you are helpful!

     

Pneumatic valves are now widely used in various industries, pneumatic actuators technology is getting better and better, domestic pneumatic actuators and imported pneumatic actuators are getting smaller and smaller, more and more types. Xiao Bian to introduce you to the pneumatic actuators of the 15 kinds of test methods for your reference.

1, the nonlinear deviation test: input control gas signal 0.02Mpa (0%), and then gradually increase the input signal up to 0.10Mpa (100%), then the signal down to 0.02Mpa (0%), so that the implementation of the full travel And record the stroke value corresponding to the increase of 0.008Mpa signal pressure. The actual deviation between the actual pressure-travel relationship and the theoretical value is less than 1%

2, positive and negative travel variation test: the same as the nonlinear deviation test method, the actual positive and negative pressure - stroke relationship, the same pressure under the cylinder piston positive and negative stroke value of the maximum difference of ≤ 1%;

3, the sensitivity test: respectively, the signal pressure 0.03,0.06,0.09Mpa the trip, increase and reduce the pressure, the test cylinder piston rod to start moving 0.1mm when the required signal pressure change value, the maximum change to ≤ 0.2%;

4, the piston cylinder sealing test: 0.5 Mpa pressure into the cylinder of any air chamber, and then cut off the gas source, in minutes 10 minutes, the cylinder pressure drop should not exceed 0.01 Mpa; 

5, the pneumatic actuator fixed to the calibration table, respectively, access to good gas source, control the gas source and displacement detection link; calibration instrument on the instrument calibration accurate;

6, the mechanical zero calibration: input 4mA current signal (0%), control the gas signal should be 0.02Mpa, then the cylinder piston stroke should be zero; if not zero, you can adjust the zero screw on the screw adjustment zero ( Zero point tight tight nut); zero and range need to be adjusted repeatedly; zero error ≤ 1%;

7, mechanical full scale calibration: input 20mA current signal (100%), control gas signal should be 0.10Mpa, then the cylinder piston stroke should be the upper limit; if not the upper limit, by adjusting the range of tension spring To adjust the range (range of small loose spring, large range of tight tension spring); zero and range need to be adjusted; full-scale error to ≤ 1%;

8, the position transmitter electrical full-scale detection: input 20mA current signal (0.1 Mpa), then adjust the transmitter internal range potentiometer to make the output current of 20mA; electrical full-scale error should be ≤ 1%;

(50%), 16mA current (75%), 20mA current (100%), input current 4mA current (0%), and then gradually increase the input signal 8mA current (25%), 12mA current (50%), 16mA current (75%), 20mA current (100%), , 0%, 50%, 100% point feedback current error should be ≤ 1%, 25%, 75% point feedback current error should be ≤ 2%, taking into account the nonlinearity of the linear displacement converted into angle change;

10, the position feedback current positive and negative stroke variation test: the same as the cylinder positive piston reverse stroke variation test method, the actual positive and negative position feedback current - travel relationship, the same feedback current value of the cylinder piston positive and negative stroke value of the maximum difference Value to ≤ 1%;

11, the mechanical range of midpoint positioning: zero and range alignment, the input 12mA current signal (50%, 0.06Mpa), adjust the location of the transmitter connecting rod position, so that at that point to maintain vertical and horizontal;

12, full stroke deviation calibration: input control gas signal 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 to take the full trip, the points are ≤ 1.5% deviation;

13, the position transmitter electrical zero detection: open the position transmitter cover, connected to the wire; input 12mA current signal (0.06 Mpa), then adjust the transmitter round eccentric wheel, so that the above black line and Circuit board above the white line alignment; and then enter the 4mA current (0.02 Mpa), then adjust the transmitter zero potentiometer to make the output current of 4mA; electrical zero error should be ≤ 1%;

14, make a good check records, according to the contents of the checklist on the item one by one to fill out, inspection personnel must sign;

15, the above test done after passing, should be the location of the transmitter terminal plug, tighten the back cover, and then the valve positioner gas inlet with a plastic plug to block the good;

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