These valves come in a range of diameters from 2 1/2 inches to 8 inches to accommodate systems of many sizes. All are made form durable PVC to offer the benefits of this corrosion resistant, pressure resistant material. This means they can be used indoors and outdoors, in systems using everything from plain water to corrosive chemicals. PVC swing check valves are commonly seen in pumping systems where backflow would damage expensive components. These valves are equipped with EPDM seals and socket ends, which makes installation simple. Customized ends or sizes may be available by custom order.
Swing check valves contain a flap or disc inside the valve that is the same diameter as the interior diameter of the pipe. This flap or disc hangs down to block the flow of the liquid. When fluid flows through the valve in the forward direction, the pressure of the fluid lifts the flap out of the way, allowing the liquid to flow. The hinge pin at the top of the valve ensures that the flap closes when the flow stops, with the weight of the flap itself holding the valve closed. Any backward flow is immediately stopped. All of this happens automatically, so there is no work on the user's part required to make the valve function properly. This process does create turbulence in the fluid because the flap sits on top of the flowing liquid, which creates a larger pressure drop than other valve types.