Some service stations and commercial fueling facilities rely on a suction pumping system. In such systems, various types of “check” valves such as angle check valves, vertical check valves and foot valves are used to hold product in the piping when the pumps are turned off.

An angle check valve is usually located at the top of the tank. Product enters the valve through the bottom and makes a 90-degree turn before it exits, thus the term “angle check.”

See also Check valve.