Butterfly-type check valve

A butterfly-type check valve employs a secondary check valve that is carried on the valve plate. The valve plate is revolvable and translatable relative to the pivot shaft. In operation, the check valve opens in response to a change in aerodynamic forces which act on the valve plate, the change being effected as a response to the opening of the secondary check valve. As the valve plate rotates to an open position, its revolutionary movement relative to the shaft changes the location of pivot points relative to the surface of the plate. This changes the areas of the surface on both sides of the pivot points so that the aerodynamic forces cause the valve to open still further. A butterfly-type check valve, comprising: a duct defining an elongate flow path for fluid, a shaft supported across said duct and extending transversely across said flow path, said shaft defining a longitudinal axis: a plate-like valve member having a hole formed therethrough; said member being disposed in said flow path substantially parallel to said shaft: said member being secured to said shaft such that said member is capable of both revolutionary and translational movement relative to said axis; and gating means secured to said member and cooperable therewith for forming a secondary check valve that is operable to permit flow through said hole in one direction and to substantially prevent flow through said hole in an opposite direction. The invention is a butterfly-type check valve. The salient features of the invention in its broadest aspect are two. The first is that the butterfly plate is secured to the shaft in such manner that the plate is capable of revolutionary movement relative to the shaft, whereby the revolutionary movement effects translation of the plate relative to the shaft. The second is the provision of a secondary check valve or pilot valve carried on the plate. The importance of the pilot valve is that it provides a means for initially opening the check valve in response to aerodynamic forces which might otherwise tend to keep the butterfly plate in a closed position The importance of the first feature is that as the plate revolves and translates relative to the shaft, it also translates relative to a pivot line about which the plate can turn Thus, the position of the pivot line relative to the plate varies with the angle of rotation of the plate. The advantages thereby provided are better understood by reference to the following description, which includes the appended claims and accompanying drawings.

                                                                                 Shanghai Remy Valve Manufacturing Co., Ltd.

2011-12-26 05:05