Check valve for backflow preventer

A check valve for a backflow preventer having a housing and a fluid flow channel therethrough, the check valve comprising:

• a seat including a sealing edge;
• a poppet including a sealing portion, the poppet movable between a closed position and an open position, the sealing portion of the poppet positioned against the seat and inhibiting fluid flow past the seat while the poppet is in the closed position, the poppet spaced apart from the seat and permitting fluid flow past the seat while the poppet is in the open position;
• a guide portion coupled to the seat and including a first guide surface and a second guide surface;
• a first stem coupled to the poppet and movable along the first guide surface;
• a second stem coupled to the poppet and movable along the second guide surface;
• and
• a biasing member coupled between the first stem and the second stem, the biasing member exerting a biasing force to draw the first stem and the second stem toward one another, the first guide surface and the second guide surface having a shape that transfers at least a portion of the biasing force in a direction that is normal to the sealing edge while the poppet is in the closed position.

A check valve for a backflow preventer having a housing and a fluid flow channel therethrough, the check valve comprising:

• a seat including a sealing edge;
• a poppet including a sealing portion, the poppet movable between a closed position and an open position, the sealing portion of the poppet positioned against the seat and inhibiting fluid flow past the seat while the poppet is in the closed position, the poppet spaced apart from the seat and permitting fluid flow past the seat while the poppet is in the open position;
• a guide portion coupled to the seat and including a first guide surface and a second guide surface;
• a first stem coupled to the poppet, the first stem including a first roller for engaging the first guide surface;
• a second stem coupled to the poppet, the second stem including a second roller for engaging the second guide surface;
• and
• a biasing member coupled between the first stem and the second stem, the biasing member exerting a biasing force to draw the first stem and the second stem toward one another, thereby biasing the sealing portion of the poppet against the sealing edge while the poppet is in the closed position, at least one of the first roller and the second roller engaging a corresponding surface of the first guide surface or the second guide surface that is angled such that the biasing force of the biasing member creates an effective closing force that biases the poppet towards the closed position.