A check valve is a valve whose opening and closing components are discs, which by virtue of their own mass and operating pressure prevent the medium from returning. It is an automatic valve, also referred to as an isolation valve, return valve, one-way valve, or check valve. Lift type and swing type are the two categories under which the disc can move.

The valve stem that powers the disc in the globe valve and the lift check valve share a similar structural design. The medium enters through the lower side input and exits through the upper side outlet (upper side). The valve opens when the inlet pressure exceeds the total of the disc weight and its flow resistance. The valve is shut off when the medium is flowing in the opposite direction.

The lift check valve’s operation is similar to that of the swing check valve in that both include rotating swash plates. In order to stop water from flowing backwards, check valves are frequently utilized as bottom valves in pumping equipment. A safety isolation function can be performed via a check valve and globe valve combination. The excessive resistance and inadequate sealing when closed are a drawback.

In lines serving auxiliary systems where pressure may increase above system pressure, check valves are also employed. Swing check valves and lifting check valves are the two primary types of check valves. Swing check valves rotate with the center of gravity (moving along the axis).

This valve’s job is to restrict the flow of the medium to one direction while blocking the flow in the other direction. This valve often operates automatically. The valve disc opens when the fluid pressure is traveling in one direction; when the fluid pressure is flowing in the other direction, the valve seat is affected by the fluid pressure and the weight of the valve disc, which blocks the flow.

This category of valves includes check valves, such as swing check valves and lift check valves. The door-shaped disc of the swing check valve freely leans on the sloping seat surface thanks to a hinge mechanism. The valve clack is constructed in the hinge mechanism so that it has enough swing room and can make complete and true contact with the valve clack seat in order to guarantee that it can always reach the proper position of the seat surface.

Depending on the required performance, discs can be fully constructed of metal or have leather, rubber, or synthetic covers on the metal. The fluid pressure is virtually completely unhindered when the swing check valve is fully opened, hence the pressure loss through the valve is minimal.

The sealing surface of the valve seat on the valve body is where the lift check valve disc is situated. The rest of the valve is similar to a globe valve, with the exception that the disc can rise and fall freely. When there is a backflow of the medium, the valve disc falls back to the valve seat, cutting off the flow. Fluid pressure lifts the valve disc off the sealing surface of the valve seat. The disc may be made entirely of metal, or it may have rubber rings or pads inlaid into the disc frame, depending on the usage circumstances.

The lift check valve has a narrower fluid passageway than the swing check valve, which results in a bigger pressure drop via the lift check valve and a lower swing check valve flow rate.