A valve that is designed to allow the fluid to flow in a given direction but closes to prevent backflow. Types include swing check, tilting disc check and wafer check. Check valves (also called non-return valves) are usually self-acting.
A valve which regulates the flow or pressure of a fluid. Control valves normally respond to signals generated by independent devices such as flow meters, temperature gauges, etc. Control valves are normally fitted with actuators and positioners. Pneumatically-actuated globe valves are widely used for control purposes in many industries, although quarter-turn types such as (modified) ball and butterfly valves may also be used.
These are valves suited for use at temperatures below - 40 degrees Celsius.