Possible failures, causes and remedies:
  Butterfly check valve body and bonnet joints at the leakage, the nut is not tight or loose tight, can be re-adjusted. Flange sealing surface damage or accumulation of dirt, should be modified to seal the surface or remove dirt. The gasket is damaged and the new gasket should be replaced. Flap and valve seat seal surface leakage. Seal between the sealing surface with dirt, can be cleaned. Sealing surface damage, re-grinding or re-surfacing and processing.
Butterfly valve test and adjustment:
  Butterfly check valve is manual, pneumatic, hydraulic, electric parts in the factory are strictly debugged, the user in the re-inspection sealing performance, the import and export sides should be evenly fixed, close the disc valve, the pressure on the import side , In the export side to observe whether the phenomenon of leakage in the pipeline before the strength test, the disc should be opened to prevent damage to the seal. Butterfly valve factory has been rigorously inspected and tested, but there are also individual products in the transport of automatic screw displacement, need to re-adjust, pneumatic, hydraulic, etc., please refer to supporting the use of drive instructions. Electric drive disc valve factory has been the control of the Kai, closed trip tune. In order to prevent the power is connected to the wrong direction, the user first turn on the power, the first open to the semi-open position, press the electric switch to check the direction of the valve and the valve can be the same direction.
Structural features:
  Butterfly check valve in the fully open condition, the fluid pressure is almost unimpeded, so the pressure drop through the valve is relatively small. The flap of the lift check valve is located on the valve seat sealing surface of the valve body. This valve in addition to the valve can be free to lift, the rest as the same as the valve, the fluid pressure so that the valve from the valve seat sealing surface lift, the media back to the valve back to the valve seat, and cut off the flow. Depending on the conditions of use, the flap may be of the all-metal structure or in the form of a rubber pad or rubber ring in the flap frame. Like the shut-off valve, the passage of the fluid through the lift check valve is also narrow, so the pressure drop through the lift check valve is larger than the swivel check valve and the flow of the swivel check valve is limited Very few