Quantong Talking about Checking and Checking Steps of Pneumatic Diaphragm Control Valves
2021-06-29 15:02:52
Pneumatic diaphragm control valve is an extremely important link in the automatic adjustment system of process production. In order to ensure its normal operation, 15 pneumatic diaphragm control valves must pay attention to the installation of attention, and before installation or after maintenance should be based on the actual needs of the necessary checks and check. The distribution inspection and final inspection are performed according to the regulating valve, pneumatic actuator and assembly.
First, the inspection of the regulating valve 1. Check the leakage of the sealing stuffing box and other joints. Check the temperature of the room temperature water to adjust the valve nominal pressure of 1.1 times or the maximum operating pressure of 1.5 times the pressure, according to open the spool Pass into one end of the regulator and close the other end. The pressure was maintained for 10 minutes while the valve stem moved back and forth 1 to 3 times per minute. There should be no leakage at the junction of the glands and other components.
2. Leak detection when closed 2.1 Water Injection Leak Check For a two-seat control valve, it is generally possible to check for leaks using a simple water injection method. The signal pressure is input to the diaphragm air chamber to close the regulator (air valve input 1.2kg/cm2 signal pressure, air valve signal pressure zero). Water at room temperature is injected into the inlet of the regulating valve, and there should be no significant drip at the other end without pressure.
2.2 Hydraulic Pressure Leakage Check This method can be used for single-seat regulating valves, angle-type regulating valves, and diaphragm valves used for accidental shut-off or requiring close shut-off.
Input signal pressure to the diaphragm chamber to close the regulator. The temperature of room temperature water, with a constant pressure of 10kg/cm2 to open the end of the valve in the direction of open the valve, with a stopwatch and measuring cup at the other end of the leakage should not exceed the allowable value.
2.3 Pressure Leakage Check For Dg ≤ 3/4" single seat control valve and angle type control valve, input signal pressure to the diaphragm air chamber to close the control valve and press the compressed air with 4kg/cm2 pressure to open the valve core. Method of access to one end of the regulating valve, cut off the air supply for 3 minutes, the pressure drop should be less than 0.15kg/cm2.
2. Pneumatic Actuator Inspection 1. Checking the tightness of the membrane chamber When the signal pressure range of the regulator's nameplate is 0.2 to 1 kg/cm2 (this is the same hereinafter), the compressed air of 0.8 kg/cm2 will be passed into the membrane chamber and cut off. For gas source, lasting 5 minutes, the pressure drop in the membrane chamber should not exceed 0.007kg/cm2 (5mmHg).
2. Push rod movement and stroke inspection 2.1 Input the film air chamber with signal pressure in the range of 0 to 1 kg/cm2 to increase and decrease the signal pressure in a reciprocating manner. The movement of the push rod should be uniform and flexible without any chattering phenomenon.
2.2 Adjust the pre-compression force of the compression spring so that the push rod starts to start when the signal pressure is 0.15 kg/cm2 (the starting signal pressure is 0.2 kg/cm2 when used with the unit combination meter).
2.3 To increase and decrease the signal pressure with a pressure range of 0.2-1.0 kg/cm2, the stroke of the push rod should meet the maximum travel requirement of the regulating valve.
Third, the assembly of the inspection 1. Valve assembly should be checked before assembly, valve seat, valve stem for defects. After grinding, the contact between the valve plug and the valve seat should be tight, and the stem should be straight and smooth.
2. After the regulator valve is assembled with the actuator, the signal pressure to close the regulator valve is input to the diaphragm air chamber, and the valve stem length is adjusted so that the valve plug is in close contact with the valve seat. For the air valve input signal pressure is 0.95kg/cm2, when combined with the unit combination instrument is 1.0kg/cm2; for the air open valve input signal pressure is zero.
IV. Checking of Pneumatic Thin Film Regulating Valve 1. Always point deviation check Enter signal pressure of 0.2kg/cm2 into the membrane chamber, then increase the signal pressure to 1.0kg/cm2. The valve stem should take the full stroke and then reduce the signal. Pressure to 0.2kg/cm2. Measure the stem travel at 1.0 kg/cm2 and 0.2 kg/cm2. The start and end deviations should not exceed the permissible values.
2. Full stroke deviation check Enter the signal pressure of 0.2 kg/cm2 into the membrane chamber, then increase the signal pressure to 1.0 kg/cm2, and the valve stem should take the full stroke. Measured full travel deviation does not exceed the allowable value.
3. Nonlinear deviation check Hangzhou Quantong Instrument Valve Co., Ltd. specializes in the production of self-regulating valve, nitrogen sealing valve, pneumatic control valve, electric control valve, pneumatic shut-off valve and other regulating valve products, the main products are self-regulating valve, nitrogen Sealing valves, pneumatic diaphragm control valves, etc.
Original source: Spring valve http://
First, the inspection of the regulating valve 1. Check the leakage of the sealing stuffing box and other joints. Check the temperature of the room temperature water to adjust the valve nominal pressure of 1.1 times or the maximum operating pressure of 1.5 times the pressure, according to open the spool Pass into one end of the regulator and close the other end. The pressure was maintained for 10 minutes while the valve stem moved back and forth 1 to 3 times per minute. There should be no leakage at the junction of the glands and other components.
2. Leak detection when closed 2.1 Water Injection Leak Check For a two-seat control valve, it is generally possible to check for leaks using a simple water injection method. The signal pressure is input to the diaphragm air chamber to close the regulator (air valve input 1.2kg/cm2 signal pressure, air valve signal pressure zero). Water at room temperature is injected into the inlet of the regulating valve, and there should be no significant drip at the other end without pressure.
2.2 Hydraulic Pressure Leakage Check This method can be used for single-seat regulating valves, angle-type regulating valves, and diaphragm valves used for accidental shut-off or requiring close shut-off.
Input signal pressure to the diaphragm chamber to close the regulator. The temperature of room temperature water, with a constant pressure of 10kg/cm2 to open the end of the valve in the direction of open the valve, with a stopwatch and measuring cup at the other end of the leakage should not exceed the allowable value.
2.3 Pressure Leakage Check For Dg ≤ 3/4" single seat control valve and angle type control valve, input signal pressure to the diaphragm air chamber to close the control valve and press the compressed air with 4kg/cm2 pressure to open the valve core. Method of access to one end of the regulating valve, cut off the air supply for 3 minutes, the pressure drop should be less than 0.15kg/cm2.
2. Pneumatic Actuator Inspection 1. Checking the tightness of the membrane chamber When the signal pressure range of the regulator's nameplate is 0.2 to 1 kg/cm2 (this is the same hereinafter), the compressed air of 0.8 kg/cm2 will be passed into the membrane chamber and cut off. For gas source, lasting 5 minutes, the pressure drop in the membrane chamber should not exceed 0.007kg/cm2 (5mmHg).
2. Push rod movement and stroke inspection 2.1 Input the film air chamber with signal pressure in the range of 0 to 1 kg/cm2 to increase and decrease the signal pressure in a reciprocating manner. The movement of the push rod should be uniform and flexible without any chattering phenomenon.
2.2 Adjust the pre-compression force of the compression spring so that the push rod starts to start when the signal pressure is 0.15 kg/cm2 (the starting signal pressure is 0.2 kg/cm2 when used with the unit combination meter).
2.3 To increase and decrease the signal pressure with a pressure range of 0.2-1.0 kg/cm2, the stroke of the push rod should meet the maximum travel requirement of the regulating valve.
Third, the assembly of the inspection 1. Valve assembly should be checked before assembly, valve seat, valve stem for defects. After grinding, the contact between the valve plug and the valve seat should be tight, and the stem should be straight and smooth.
2. After the regulator valve is assembled with the actuator, the signal pressure to close the regulator valve is input to the diaphragm air chamber, and the valve stem length is adjusted so that the valve plug is in close contact with the valve seat. For the air valve input signal pressure is 0.95kg/cm2, when combined with the unit combination instrument is 1.0kg/cm2; for the air open valve input signal pressure is zero.
IV. Checking of Pneumatic Thin Film Regulating Valve 1. Always point deviation check Enter signal pressure of 0.2kg/cm2 into the membrane chamber, then increase the signal pressure to 1.0kg/cm2. The valve stem should take the full stroke and then reduce the signal. Pressure to 0.2kg/cm2. Measure the stem travel at 1.0 kg/cm2 and 0.2 kg/cm2. The start and end deviations should not exceed the permissible values.
2. Full stroke deviation check Enter the signal pressure of 0.2 kg/cm2 into the membrane chamber, then increase the signal pressure to 1.0 kg/cm2, and the valve stem should take the full stroke. Measured full travel deviation does not exceed the allowable value.
3. Nonlinear deviation check Hangzhou Quantong Instrument Valve Co., Ltd. specializes in the production of self-regulating valve, nitrogen sealing valve, pneumatic control valve, electric control valve, pneumatic shut-off valve and other regulating valve products, the main products are self-regulating valve, nitrogen Sealing valves, pneumatic diaphragm control valves, etc.
Original source: Spring valve http://
Head-loop Fish Type Mask Machines
Fish Face Mask Machine ,Fish Type Mask Making Machines,Head-Loop Fish Type Face Mask Machines,Ear-Loop Fish Type Face Mask Machines
Broadfair Automation Equipment Co., Ltd. , https://www.broadfairmachine.com