What is swing type check valve

Many guys in the field just call the swing type check valve a "flap valve" or a non-return valve. The structure is actually quite simple-it's just a disc swinging on a hinge pin inside a heavy-duty ductile iron body. Here's the deal on how it works: forward water pressure pushes the flap open, but the moment your pump stops, gravity and the back-pressure swing that disc shut to block any backflow instantly. Just keep an eye on the installation direction; it works perfectly in horizontal or vertical-up lines, but never install it facing downward or the disc won't seat properly. It's the go-to choice for fire protection and HVAC systems where you need full flow without losing pressure.