Check valves (also known as non-return valves) are an important type of directional control valves because they only allow flow of fluid in one direction. There is a spring inside its body that pushes a disc into the valve seat to keep it closed. The flow must therefore exceed the force of the spring. In the opposite direction, however, the flow pushes the disc into the seat, keeping the valve closed.
Check valves are designed to have as little pressure loss and low opening differential pressure as possible while preventing fluid backflow. Spring-loaded non-return valves can be installed in any position, but opening pressure is the lowest at the vertical position and downward flow direction. The exception are larger interflanged valves, which close by gravity of their own flow. Such valves do not need to be installed so that the force of gravity closes them.
Non-return valves can be used in domestic water distribution systems, where they prevent backflow through water meters - and thus inaccurate reading of consumption. Another useful function is its use in sewer, where it ensures a smooth outlet into the public sewer network and protects against flooding of your house. We also sell non-return valves for heating systems.
When choosing non-return valves, it is necessary to distinguish several types according to the connection - there are threaded, interflanged butterfly valves and valves with clamping rings. It also depends on whether they will be used in copper or steel pipes. Check valves also have different temperature ranges.
Some flanged butterfly valves are not spring-loaded, because due to the large size they are only controlled by the flow direction.
In terms of material, for example the ABO VALVE 824B080 DN 80 check valve body is made of ductile iron and the plate is made of stainless steel.
ABO VALVE 800 series of swing check valves are mainly used for water treatment, heating systems and oils.