Pneumatic actuators inspection standard and method

One, check to prepare and appearance inspection

1 all test instrument are required to shift to an earlier date 30 minutes energizing preheating;

2 test air pressure to meet 0.6 + / - 0.1 Mpa;

3 actuator appearance no significant injury, guide gas copper pipe have no obvious dented mark and assembly firmly;

4 position transducer connecting screw rod length must conform to be seized actuator type of technical requirements; Fastening in transmitter shaft connecting rod and connecting screw rod should be a plane perpendicular to the horizontal plane;

Second, testing standard and method

1 will pneumatic actuators (pneumatic actuators) fixed to check on the stage, respectively after good gas source, control air and displacement detection connecting rod; Will check on the stage instrument adjusting accurate;

2 mechanical zero calibration: input 4 ma current signal (0%), control air signal should be 0.02 Mpa, the cylinder piston stroke should be zero; If not for zero, but by adjusting the zero screw the nut zeroing (zero high tight nut); Zero and range requires repeated adjustment; Zero error to 1% or less,

3 mechanical full scale calibration: input 20 ma current signal (100%), control air signal should be 0.1 Mpa, the cylinder piston stroke should be upper limit; If not for upper limit value, but through adjusting range extension spring aid to adjust range (range small pine tension spring, range big tight tension spring); Zero and range requires repeated adjustment; Full scale error to 1% or less,

4 mechanical range neutral positioning: zero and range alignment, input 12 ma current signal (50% 0.06 Mpa,), adjust the position transducer connecting rod position, make the point to keep and horizontal vertical;

5 full stroke deviation calibration: input control gas signal 0.02 Mpa (0%), 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%), make the cylinder piston go completely stroke, each point deviation are to 1.5% or less,

6 nonlinear deviation test: input control gas signal 0.02 Mpa (0%), then gradually increase the input signal until 0.10 Mpa (100%), then the signal is very down 0.02 Mpa (0%), 0.008 Mpa make actuators go completely stroke control engineering net all rights reserved, and record every increase or decrease signal pressure corresponding stroke value, the actual pressure ━ stroke with the theoretical relationship between the nonlinear deviation to 1% or less,

7 and stroke variation test: and nonlinear deviation test method is same, actual positive and negative pressure ━ stroke relationship, the same pressure value of the cylinder piston positive and negative stroke value of the maximum difference to 1% or less,

8 sensitivity test: the signal pressure respectively 0.03, 0.06, 0.09 Mpa trip place, increase and reduce the pressure, the test in the cylinder piston rod start moving when 0.1 mm needed signal pressure change value, the biggest change to 0.2% or less,

9 piston cylinder sealing test: will be 0.5 Mpa pressure access cylinder let a room, then cut off the air, in points and 10 minutes in, in the cylinder pressure drop value should not be more than 0.01 Mpa;

10 position transducer electrical zero detection: open position transmitter cover, then good wire; Input 12 ma current signal (0.06 Mpa), the adjustment in the transmitter circular eccentric, make its above the black thread and the circuit board the white line alignment; And then input 4 ma current (0.02 Mpa), at this time can be adjusted within the transmitter zero potentiometer to make the 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 (0.1 Mpa), at this time can be adjusted within the transmitter adjustable range potentiometer to make the output current to 20 ma, Electrical full range error should be 1% or less,

12 position feedback current full stroke deviation calibration: input 4 ma current (0%), then gradually increase the input signal and ma current (25%), 12 ma current (50%), 16 ma current (75%), 20 ma current (100%), considering the linear displacement into the changes in the Angle of nonlinear error, 0%, 50%, 100% point feedback current error should be acuities were 1%, 25%, 75% point feedback current error should be 2% or less,

13 position feedback current positive and negative stroke variation test: with cylinder is piston revesal variation test method is same, actual positive position feedback current ━ stroke relationship, the same feedback current value of the cylinder piston positive and negative stroke value of the maximum difference to 1% or less,

14 do check record, according to the check form the content of item by item fill in, inspection personnel must sign;

15 all finish after passing test, should will position transmitter inside connection terminal plug good, tighten the back cover, and then will pneumatic valve positioner air inlet with plastic plug plugging good;