Pneumatic actuators testing standard and method

1. To fix the pneumatic actuators check first on the stage, then good gas source, control air displacement detection connecting rod, and will check on the instrument calibration accuracy;

2. Mechanical zero calibration: input 4 ma current signal, control signal should be 0. 02 mpa, and the cylinder piston stroke should be zero, zero error to 1% or less;


3. Mechanical full scale calibration: input 20 ma current signal, control signal should be 0. 1 mpa, and the cylinder piston stroke should be upper limit, full scale error to 1% or less;


4. Mechanical span midpoint location: after zero and range alignment, 12 ma current signal input, adjust the position of the link rod position transmitter in the point to keep vertical and horizontal plane,


5. All travel deviation calibration: input control signal is 0. 02 mpa and gradually increase the input signal is 0. 036Mpa、0. 052Mpa、 0. 068Mpa、0. 084 mpa, 0。 1 mpa, stroke cylinder piston go completely, each point deviation to 1 or less. 5%;


6. Nonlinear deviation test: the input control signal is 0. 02 mpa and gradually increase the input signal to zero. 10 mpa, and has reduced the signal is 0. 02 mpa, and record each signal pressure increase or decrease the corresponding travel value, the actual stress and nonlinear deviation between the theoretical value to 1% or less;


7. And schedule variation test: same as the nonlinear deviation test method, the actual values of positive and negative pressure and air pressure under the big difference between the piston and cylinder stroke value should be 1% or less;


8. Sensitivity test: 0, the pressure signal, respectively. 3, 0. 6, 0. 09 mpa stroke, increase and reduce pressure, test at the beginning of the cylinder piston rod mobile 0. 1 mm when the desired signal pressure value change, its large changes to 0 or less. 2%;


9. Piston cylinder sealing test: will be 0. 5 mpa pressure access any in chamber of the cylinder, and then cut off the gas source, in 10 minutes, the pressure in the cylinder is the decline in value should not exceed 0. 01 mpa;


10. Electrical zero position transmitter detection: open the cover, position transmitter connected wires; 12 ma current signal input ( 0. 06Mpa） , adjust the transmitter inside the circular eccentric at this time, make its black line above the plate above the white line with line road alignment; Then enter 4 ma current ( 0. 02Mpa） , this time can be adjusted within the transmitter zero potentiometer output current is 4 ma; Electric zero error should be 1% or less;


11. Position transducer electrical full scale testing: input (20 ma current signal 0. 1Mpa） , this time can be adjusted within the transmitter tuning range potentiometer to 20 ma output current; Electrical error of range should be 1% or less;


12. Full position feedback current stroke deviation calibration: input 4 ma current, then gradually increase the input signal is 8 12 ma ma current, current, 16 ma, 20 ma current, 0%, 50%, 100% point error of feedback current should be 1% or less, 25%, 75% point error of feedback current should be 2% or less;


13. Positive position feedback current stroke variation test: with cylinder is a piston revesal variation test method is the same, the actual positive position feedback current, under the same feedback current value of the big difference between the piston and cylinder stroke value should be 1% or less;


14. All testing after qualified, should put good position transmitter terminals within, tighten the back cover, then pneumatic valve positioner air inlet with plastic plug plugging.








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