Pneumatic pneumatic control valve leakage how to test?

Want to test pneumatic pneumatic - valve leakage is not standard, can be done through some test, test after the conclusion can also sums up the standard of pneumatic pneumatic - valve leakage. Pneumatic pneumatic control valve leakage standard test, first of all need to test medium pressure, such as external regulation control valve pressure should be 3. 5kg/cm? , when the pneumatic - valve to allow the differential pressure value is less than 3. 5kg/cm? When this is the rules allow the differential values. Test medium shall be 10 - Clean fluid 50 ℃ ( Water or kerosene) And gas ( Air or nitrogen) , due to the different working conditions, other medium under test will have to produce error, so suggested that medium is recommended to complete the test, the test medium shall be in accordance with the relevant provisions to add the medium inside the valve, the valve can be connected through the atmosphere or export loss to the low voltage measuring device, going into the atmosphere when determining the valve below after connecting pipe section is completely filled with medium, this time can be measured to pneumatic - valve leakage. Test pneumatic pneumatic - valve actuator, actuator signals should be combined with pressure, it is important to ensure that the pneumatic control valve is closed, when in the test, in view of the pneumatic actuators, pneumatic open and the handling of the closed type is different, the signal of gas open pressure must be zero state, models of gas closed type pressure shall be the input of the maximum signal pressure upper limit to the lower limit of the minimum pressure value. Type test to cut off the control valve with actuator, signal pressure shall be the design rules of the actuator.