Main causes of
Diaphragm Valve common faults
Diaphragm valve is specially used to control non corrosive or general corrosive medium. The inner surface of valve body is unlined or covered with optional rubber. It is suitable for different working temperature and liquid pipeline.
Cause analysis of common faults
1. Diaphragm damage
1. Causes: rubber, fluoroplastic diaphragm aging; prevention and elimination methods: regular replacement;
2. Causes: the operating pressure is too high to crush the diaphragm; prevention and elimination methods: the operation force should be small, pay attention to the closing mark;
3. Causes: foreign matters are embedded between diaphragm and valve seat, pressing or wearing diaphragm; prevention and elimination methods: do not force closing during operation, open and close repeatedly several times up and down, after flushing away foreign matters, formally close the valve; replace the diaphragm timely after damage;
4. Causes: the opening height is too high, breaking the diaphragm; prevention and elimination methods: it is not suitable to open too high during operation.
2. Operation failure
1. Causes: diaphragm and valve disc fall off; prevention and elimination methods: do not open too high, after falling off, repair or replace diaphragm in time;
2. Causes: the connecting pin between the valve stem and the valve disc falls off or is broken due to wear; prevention and elimination methods: it is not allowed to exceed the top dead center when opening, and it should be repaired in time after falling off;
3. Causes: wear and seizure of the connection between the nut of the movable valve rod, the valve cover and the valve stem; prevention and elimination methods: regular cleaning, coating graphite and molybdenum disulfide dry powder for lubrication on the active part; fluorine diaphragm structure can add a small amount of grease to the active part.
3. The handwheel operation is not flexible
1. Causes: valve rod bending; prevention and Troubleshooting: replace the valve rod;
2. Causes: thread damage; prevention and elimination methods: repair the thread and add lubricant.
4. Diaphragm valve cannot open and close automatically
1. Causes: the air source pressure is too low; prevention and elimination methods: increase the gas supply pressure;
2. Causes: the spring jacking force is too large; prevention and elimination methods: reduce the spring jacking force;
3. Causes: rubber diaphragm damage; prevention and Troubleshooting: replace diaphragm.
5. Leakage at the joint of valve body and valve cover
1. Causes: loose connecting bolts; prevention and elimination methods: fastening connecting bolts;
2. Causes: the inner rubber layer of the valve body is broken; prevention and elimination method: replace the valve body
