Abstract: Backflow preventers permit forward fluid flow through the backflow preventer while preventing backflow or back-siphonage of contaminated fluid. A backflow preventer includes an inlet, an outlet aligned with the inlet in a stacked configuration, a coupling portion providing fluid communication between the inlet and the outlet, the coupling portion including a first check valve upstream of a second check valve. A valve body of the first check valve inhibits backflow in a direction from the outlet to the inlet through the first check valve even when the valve body is in an open position.

Abstract: A check valve is provided to prevent backflow of fluid in a backflow preventer or plumbing system having a housing and a fluid flow channel therethrough. The check valve includes a valve seat, a poppet movable between a closed position where the poppet is positioned against the valve seat and inhibits fluid flow past the valve seat and an open position where the poppet is spaced apart from the valve seat and permits fluid flow past the valve seat. The check valve includes a guide portion 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 for biasing the poppet to the closed position.

Abstract: Backflow preventers permit forward fluid flow through the backflow preventer while preventing backflow or back-siphonage of contaminated fluid. A backflow preventer includes an inlet, and an outlet positioned in a stacked configuration with respect to the inlet. The backflow preventer includes a first check valve located between the inlet and the outlet, and a second check valve located between the first check valve and the outlet with respect to the flow path. The backflow preventer further includes a coupling portion providing fluid communication between the inlet and the outlet. The coupling portion includes an offset portion that is laterally offset with respect to the inlet, and the offset portion inhibits flow of fluid from the outlet to the inlet during a backflow condition.

Abstract: A backflow preventer includes an inlet and an outlet positioned in a stacked configuration with respect to the inlet, the outlet positioned downstream of the inlet with respect to a flow path in which fluid flows from the inlet to the outlet. The backflow preventer further includes a first check valve located between the inlet and the outlet with respect to the flow path, and a second check valve located between the first check valve and the outlet with respect to the flow path. The backflow preventer includes a coupling portion providing fluid communication between the inlet and the outlet, and a diverter positioned between the inlet and the outlet. The diverter includes a baffle that inhibits fluid backflow from the outlet to the inlet.

Abstract: A check valve is provided to prevent backflow of fluid in a backflow preventer or plumbing system having a housing and a fluid flow channel therethrough. The check valve includes a valve seat, a poppet movable between a closed position where the poppet is positioned against the valve seat and inhibits fluid flow past the valve seat and an open position where the poppet is spaced apart from the valve seat and permits fluid flow past the valve seat. The check valve includes a guide portion 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 for biasing the poppet to the closed position.

Abstract: A check valve includes a housing having a fluid flow channel therethrough, a valve seat, a clapper, and a pivot link. The clapper is movable between a closed position where the clapper inhibits fluid flow past the valve seat and a fully open position where the clapper permits fluid flow past the valve seat. The pivot link includes a pivot member supported for rotation about a pivot axis, a first arm rigidly connected to the pivot member and coupled to the clapper, and a second arm rigidly connected to the pivot member and coupled to a biasing member. The pivot link transmits a biasing force from the biasing member to the clapper. An effective biasing force that is transmitted to the clapper while the clapper is in the closed position is greater than an effective biasing force transmitted to the clapper while the clapper is in the fully open position.