Various types of check valves
There are various types of check valves used in a wide variety of applications. Check valves are often part of common household items. They are available in a wide range of sizes and costs. Check valves generally are very small, simple and inexpensive. Check valves work automatically and most are not controlled by a person or any external control.
Types of Check Valves
Swing Check Valve is a check valve in which the disc, the movable part to block the flow, swings on a hinge either onto the seat to block reverse flow or off the seat to allow forward flow. The seat opening cross-section may be perpendicular to the centerline between the two ports or at an angle.
Duckbill valve is a check valve in which flow proceeds through a soft tube that protrudes into the downstream side. Back-pressure collapses this tube, cutting off flow.
Ball Check Valve is a check valve in which the closing member, the movable part to block the flow, is a spherical ball. Ball check valves are often very small, simple and cheap. They are commonly used in liquid or gel mini pump dispenser spigots, spray devices and some rubber bulbs for pumping air.
Stop-Check Valve is a check valve with override control to stop flow regardless of flow direction or pressure.
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.
Diaphragm Check Valve uses a flexing rubber diaphragm positioned to create a normally-closed valve. Pressure on the upstream side must be greater than the pressure on the downstream side by a certain amount, known as the pressure differential, for the check valve to open allowing flow. Once positive pressure stops, the diaphragm automatically flexes back to its original closed position.
