Stacked backflow preventer

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.

What is claimed is: 
     
         1 . A backflow preventer comprising:
 an inlet;   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;   a first check valve located between the inlet and the outlet with respect to the flow path;   a second check valve located between the first check valve and the outlet with respect to the flow path; and   a coupling portion providing fluid communication between the inlet and the outlet, the coupling portion including an offset portion that is laterally offset with respect to the inlet, the offset portion inhibiting flow of fluid from the outlet to the inlet during a backflow condition.   
     
     
         2 . The backflow preventer of  claim 1 , wherein the offset portion includes a lower end that is laterally offset from the inlet, wherein the relief outlet is positioned adjacent the lower end. 
     
     
         3 . The backflow preventer of  claim 2 , wherein the lower end of the offset portion extends below a lowermost fluid opening of the first check valve. 
     
     
         4 . The backflow preventer of  claim 1 , wherein the coupling portion includes a first lateral pipe and a second lateral pipe, the first lateral pipe fluidly coupled to the inlet, the second lateral pipe fluidly coupled to the outlet, wherein the offset portion is fluidly coupled between the first lateral pipe and the second lateral pipe. 
     
     
         5 . The backflow preventer of  claim 4 , wherein the first check valve is positioned in the first lateral pipe, and the second check valve is positioned in the second lateral pipe. 
     
     
         6 . The backflow preventer of  claim 1 , wherein the first check valve is positioned adjacent the inlet and the second check valve is spaced apart from the outlet. 
     
     
         7 . The backflow preventer of  claim 1 , wherein the second check valve is actuatable in a direction that is substantially perpendicular relative to an axis of the outlet. 
     
     
         8 . The backflow preventer of  claim 1 , wherein the second check valve is actuatable in a direction that is substantially perpendicular relative to an axis of the outlet. 
     
     
         9 . The backflow preventer of  claim 1 , wherein the offset portion extends in a helical manner between the inlet and the outlet. 
     
     
         10 . The backflow preventer of  claim 1 , wherein the offset portion extends in a vertical loop between the inlet and the outlet. 
     
     
         11 . The backflow preventer of  claim 1 , wherein the coupling portion includes a first end coupled to the inlet, a second end coupled to the outlet, and an intermediate portion positioned between the first end and the second end, the intermediate portion having a width that is larger than the first end and the second end, the offset portion being positioned along a periphery of the intermediate portion, wherein the first check valve and the second check valve are positioned in the intermediate portion and offset from one another. 
     
     
         12 . The backflow preventer of  claim 1 , wherein the coupling portion includes a first end coupled to the inlet, a second end coupled to the outlet, and an intermediate portion positioned between the first end and the second end, wherein the first end and the second end are oriented in a common plane. 
     
     
         13 . A backflow preventer comprising:
 an inlet;   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;   a first check valve located between the inlet and the outlet with respect to the flow path;   a second check valve located between the first check valve and the outlet with respect to the flow path; and   a coupling portion providing fluid communication between the inlet and the outlet, the coupling portion including an offset portion that is laterally offset with respect to the inlet, the offset portion inhibiting flow of fluid from the outlet to the inlet during a backflow condition, the coupling portion further including a relief outlet for draining fluid from the offset portion during the backflow condition, the coupling portion being removably coupled to the inlet and the outlet.   
     
     
         14 . The backflow preventer of  claim 13 , wherein the inlet and the outlet are secured to one another in a common body, the body including a lateral inlet portion in fluid communication with the inlet and a lateral outlet portion in fluid communication with the outlet, wherein the coupling portion is removably coupled to the lateral inlet portion and the lateral outlet portion. 
     
     
         15 . The backflow preventer of  claim 14 , wherein the coupling portion includes a first end coupled to the lateral inlet portion, a second end coupled to the lateral outlet portion, and an intermediate portion positioned between the first end and the second end, wherein the first end and the second end are oriented in a common plane. 
     
     
         16 . The backflow preventer of  claim 13 , wherein the first check valve and the second check valve are supported in the coupling portion and are oriented parallel to one another. 
     
     
         17 . The backflow preventer of  claim 13 , wherein the first check valve and the second check valve are supported in the coupling portion. 
     
     
         18 . The backflow preventer of  claim 13 , wherein the lower end of the offset pipe portion extends below a lowermost fluid opening of the first check valve, the relief outlet positioned adjacent the lower end. 
     
     
         19 . A backflow preventer comprising:
 an inlet extending along an inlet axis;   an outlet extending along an outlet axis, the 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;   a first check valve located between the inlet and the outlet with respect to the flow path;   a second check valve located between the first check valve and the outlet with respect to the flow path; and   a coupling portion providing fluid communication between the inlet and the outlet, the coupling portion including an offset pipe portion, a central axis of the offset pipe portion being offset from the inlet axis.   
     
     
         20 . The backflow preventer of  claim 19 , wherein the first check valve is actuatable in a direction that is substantially perpendicular to the inlet axis, wherein the second check valve is actuatable in a direction that is substantially perpendicular relative to the outlet axis.