A check valve, also called a one-way valve, is a device that allows the flow of fluids to move only in one direction. The primary purpose of a check valve is to prevent backflow in the system. Check valves are cheap, effective, and easy solutions to a potential issue.
A check valve prevents backflow, and thus damage to the emergency pumps, by letting hydraulic fluid flow in only one direction. Check valves can also prevent foreign particles or debris from entering the hydraulic system, further protecting pumps and other components from damage caused by contamination.
The check valve is a crucial system component for preventing backflow. Check valves help a system maintain one-way flow. They open based on the pressure of the fluid flowing through the system, then close to prevent the fluid from flowing back toward the system inlet.
The differential pressure between the outlet and inlet, at which no flow is passing through the valve. Maximum allowable back pressure is rated to 1000 psi (69 bar) for 1/4, 200 psi (14 bar) for 3/8 to 1".