Double Check Valves
A double check valve, sometimes called a double check assembly (DCA), is a device used to protect water supplies from contamination due to backflow. Double check valves consist of two spring check valves assembled in sequence, usually with a ball valve or gate valve at each end.
Double check valves are effective at preventing back pressure and siphonage. Common uses for double check valves include lawn irrigation, fire sprinkler systems, and municipal water supply lines.