How to Adjust the Sealing Performance of a Swing Check Valve?

A swing check valve is common, which can prevent reversal of flow through pipe lines and make the disc off/on automatically by medium’s force. An important quality matter is the sealing performance of its seal. But the performance of valves is affected due to its bad fit on the seal, although many factories make the disc able to be adjusted reasonably during the production of swing check valves in these years. Our company made a close investigation and research for this problem and puts forward some solutions.

The sealing surface of a swing check valve is perpendicular to the central plane. If the remote-control-lever is deviated severely and isn’t perpendicular to O plane, the sealing surface will not be perpendicular to the central plane, A\B sealing surface not paralleled and the sealing performance bad when the remote-control-lever, the disc, the rocker shaft are assembled.

The follows are the reason and solution when rocker hole is not perpendicular to the sealing surface.

A swing check valve is fixed to a position in V block with a three-end flange. Theorically, the central plane O should be horizontal. But the plane O will not be horizontal when the outer diameter of flanges at inlet and outlet is different or the outer diameter is not what is required on the drawing.

So, it is necessary to put forward certain precision about the outer diameter and process document of a three-end flange. If the drill is relatively long and the rigidity is bad, the hole certainly will not be perpendicular to the central plane O, or even worse due to its raw surface and uneven cutting force. Therefore, requirement should be written in the process document even if there is no demand for processing surface C in drawing.

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