What is a Stainless Steel Swing Check Valve?

Check valves; They are devices that allow one-way passage of liquids. These devices, which have two connection points, one of which gives the inlet of the fluid to the fluid outlet, are also called “one-way valves” or “non-return valves” in the market, since they allow the passage of the fluid in one direction. In order for it to work, a pressure difference between the fluid inlet and outlet is needed. In order for the check valve to allow flow, the pressure at the inlet must be greater than the outlet. The check valve will close when the pressure on the outlet side is greater than the inlet pressure. Check valves have different closing mechanisms. Unlike other valves, they do not need auxiliary energies (hand control, electric or pneumatic actuators) to close.

Check valves are preferred in applications where backflow will cause problems (prevention of the return of waste sewage water, the possibility of damaging an equipment, reverse-osmosis applications, etc.). Another reason for preference is that they are cheap and easily available. It is a shelf product and can generally be found in stocks.

Working Principle

In order for the check valves to open, the pressure at the time of opening is called the “Separation Pressure” or “Cracking Pressure”. As soon as the pressure on the inlet side of the check valve becomes equal and higher than the flow pressure, the check valve starts to open and the fluid is allowed to pass. Depending on the design, when the pressure on the inlet begins to drop, a flap, ball or diaphragm, depending on the design, moves against the flow direction, closing the orifice. This closure is sometimes provided by a spring and sometimes by taking advantage of gravity.