Disc Check Valve

About Disc Check Valve

These are also called nonreturn valves as they allow the flow to pass through them only in one direction and stop the flow in another direction. Because of this unique property check valves are used in some critical applications in steam systems.There are four major types of disc check valves as follows

Lift Check Valve-these work simply on the principle of gravity. When the fluid comes in the forward direction, the disc gets lifted from the seat against the gravitational force by the force of incoming fluid. The valve thus allows fluid to pass in this direction. When the fluid comes in the opposite direction, it supports the force of gravity and the disc remains on the seat, keeping the valve closed.

Swing Check Valve-In this kind of check valve, the disc or the closing element swings around a point to which it is hinged. When the fluid comes in the forward direction, the disc swings in an open position allowing the fluid to pass. When the fluid flow comes in the opposite direction, the disc swings and rests on the seat to lose it.

Spring-loaded Check Valves-In this kind of check valve, a tight shut-off is provided using a spring. the disc on the seat is held back by the spring. Even in the forward flow condition, the fluid should exert some pressure, called cracking pressure in order to open the disc against the spring pressure.

Diaphragm Type Check Valve-This kind of check valve uses diaphragms arranged in such a way that open to allow the flow only in the forward direction. When flow comes from the reverse direction, the diaphragms remain closed.