A check valve is a safety and protection valve that is used in almost all types of systems and applications where backflow creates risks of contamination, hazardous mixing of compounds, or risk to equipment and system components.
A one way check valve is an in-line valve that is designed to operate without any need for manual or automatic controls. Instead, the check valves operate by responding to drops in the upstream or inlet pressure that immediately close the valve, preventing the media from flowing backward through the valve.
Typical placement for a one way check valve includes on the inlet and outlet ports of air compressors, on the outlet ports of vacuum systems, and in chemical production, pharmaceutical manufacturing systems, or food and beverage types of systems. In all of these cases, the role of the valve is to prevent any backflow and to operate independently of the need for any type of external control.
Installation Considerations
All check valves have a cracking pressure, which is the pressure differential, or more correctly, the minimum upstream pressure, which causes the valve to close to prevent backflow. It is essential to not only choose a one way check valve that is the correct size for the pressure and flow volume but also for the pressure differential or cracking pressure required for the system.
All check valves are designed to be installed in the line in a specific orientation. With both metal and plastic check valves, this orientation is typically represented as an arrow indicating the flow in the system from the inlet to outlet ports. It is critical to install the valve in the correct direction.
Incorrect installation of the check valve means the valve does not work at all, and there is no functioning of the valve and no prevention of backflow through the system. Always double check the valve orientation before installation to prevent this common error.
