Check Valves
We offer a full range of check valves in a variety of types, sizes, pressure ratings and materials.
Also known as Non-Return Valves, A Check Valve allows fluid, liquid or gas to flow through it in only one direction. They are two-port valves, meaning they have two openings in the body, one for fluid to enter and the other for fluid to leave. Check valves work automatically and most are not controlled by a person or any external control; accordingly, most do not have any valve handle or stem. Although they are available in a wide range of sizes and designs, many check valves are small, simple, and low cost.
Some of the types of check valve we supply include:
A swing check valve is a check valve in which the disc, the movable part to block the flow, swings on a hinge or trunnion, either onto the seat to block reverse flow or off the seat to allow forward flow. This is the traditional design, and they are simple in operation. They are however, relatively large when compared to more modern designs like wafer checks. Swing checks are prone to wear at the hinge if flow is not constant (ie near a pump outlet)
A wafer check valve does not use a large body to allow the plate to swing through, but uses the pipeline itself. This significantly reduces weight and cost. The addition of springs make the valve close quicker and dampens movement in turbulent flow. Twin plate checks offer even quicker response, and do not protrude as far into the pipeline when open
A lift-check valve is a check valve in which the disc, sometimes called a lift, can be lifted up off its seat by higher pressure of inlet or upstream fluid to allow flow to the outlet or downstream side. A guide keeps motion of the disc on a vertical line, so the valve can later reseat properly. When the pressure is no longer higher, gravity or higher downstream pressure will cause the disc to lower onto its seat, shutting the valve to stop reverse flow.
A piston check is essentially a lift check valve. It has a dashpot consisting of a piston and cylinder that provides a damping effect during operation, and is therefore suitable for variable flow rates and directions.
A double check valve is often used as a backflow prevention device to keep potentially contaminated water from siphoning back into water supply lines
It is important to consider many factors in the choice of a check valve; operating temperature and pressure, media properties, orientation, turbidity of flow, frequency of operation etc
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