Basic Knowledge Of Concentric Butterfly Valve

Notices for operation and maintenance of concentric butterfly valve


1. Concentric butterfly valve must be fully open and closed periodically during operation, otherwise, the valve will rust.


2. If the closure is not strict during the closing process, the valve should be fully opened again, and the valve should be closed again after using the hydraulic pressure of the pipeline to flush the impurities in the inner wall of the pipeline.


3. Filter the impurities in the pipeline as far as possible to prevent the butterfly valve from squeezing out the sealing surface when it closes, resulting in the phenomenon that it can not be completely closed.


4. If the valve is in a larger throttling range, the back of the valve plate is prone to cavitation, which may damage the valve. Generally, the valve is used in a state larger than 15 degrees.


5. Prevent mechanical damage of valves and deteriorate the quality of valves due to erosion of sediments, chemicals or moist gases in the atmosphere.


6. Work interfaces such as threads, bearings or gears should be lubricated regularly.


When the concentric butterfly valve is in the middle opening, the operating mechanism needs to lock itself.


Concentric butterfly valve's possible faults, causes and maintenance methods

Possible FaultsPossible CausesElimination Methods
Packing Leakage1. The packing cover is not pressed.
2. The number of packing rings is less than needed.
3. The packing fails because it has been in use for too long or is not properly preserved.
1. Tighten the nut evenly.
2. Increase the number of packing rings.
3. Replace the new packing (the joints of each ring should be staggered).
Leakage between Sealing Pairs4. The sealing surface has dirt attachment.4. To remove or reprocess, trim or replace dirt.
The Drive Is Inflexible or the Closing Part Cannot Be Opened or Closed6. The packing pressure is too tight.
7. Packing gland device skew.
8. Damage to drive mechanism or connection.
6. Loosen the nut on the packing gland properly.
7. Correct packing pressure cover.
8. To remove a drive or connector for repair.
Leakage of Flange Sealing Surface at both Ends of Valve9. The sealing gasket on both sides is invalid.
10. Uneven pretightening force of flange connection bolt on both sides of pipeline。
9. Replace the gasket on both sides.
10. Tighten the connecting bolts evenly.







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