Patent ID: 7025085

Claim:
A poppet-type check valve for controlling fluid flow, comprising: (a) a valve housing having an interior for permitting fluid flow from an upstream side to a downstream side thereof; (b) at least one valve assembly disposed within the interior of the valve housing for controlling the fluid flow therethrough, said valve assembly including: (i) a valve seat positioned in the interior of the valve housing; (ii) a seal retainer positioned in the interior of the valve housing downstream from the valve seat and mounted on a stem, said seal retainer and said stem axially moveable away from the valve seat in response to fluid flow in a downstream direction at a predetermined flow rate, and axially moveable towards and into sealing engagement with the valve seat in response to a downstream fluid flow at a flow rate less than the predetermined flow rate; (iii) a plurality of springs pivotally mounted in the interior of the valve housing interconnecting the valve housing and stem for normally maintaining the seal retainer in sealing engagement with the valve seat in the absence of said predetermined fluid flow rate, said springs positioned in radial opposition to one another and extending outwardly from the stem in the downstream direction to cause the seal retainer to move away from the valve seat in response to fluid flow in the downstream direction, thereby increasing the force of the stem on the springs and causing the springs to pivot and compress to produce a diminishing resultant spring load on the stem; and (iv) a return member mounted on the stem for providing a return motion to the plurality of springs, the biasing force of the return member providing an assist to the motion of the stem in the upstream direction upon a predetermined reduction in fluid flow to assist in returning the seal retainer into sealing engagement with the valve seat.