The 4-inch flanged check valve can be divided into internal threaded check valve and butterfly check valve according to the type of construction. It also includes swing check valve and lift check valve.
The swing-type flange check valve has a hinge mechanism and a valve flap to rest against the inclined seat surface. In order to ensure that the valve flap can reach the proper position of the valve, the valve flap is designed in the hinge mechanism. So that the valve flap has enough swinging space and the valve flap is truly and comprehensively in contact with the valve seat. The flaps can all be made of metal, or they can be inlaid with leather, rubber, or synthetic coverings depending on the performance requirements. With the swing-open flange check valve fully open, the fluid pressure is almost unimpeded, so the pressure drop is relatively small. The valve flap of the lift flange check valve is located on the valve seat sealing surface of the valve body. In addition to the flap being free to be lifted and lowered, the valve is like a shut-off valve. The fluid pressure causes the flap to lift from the seat sealing surface. The backflow of the medium causes the flap to fall back onto the seat and shut off the flow. Depending on the conditions of use, the flap can be of all metal construction or it can be in the form of a rubber or rubber ring on the valve disc holder. Like the shut-off valve, the passage of the lift check valve is also narrow, so the pressure drop through the lift flange check valve is larger than the swing-type flange check valve. And the flow of the swing-type flange check valve is subject to very few restrictions.
4-inch flange check valve features
1. The valve flap is closed quickly and the water hammer pressure is small;
2, Horizontal or vertical pipeline are easy to install;
3. The flow path is smooth and the fluid resistance is small;
4, Sensitive action and good sealing;
5, The valve flap stroke is short, and the impact is small;
6, The overall structure is simple and compact, pleasing to the eye;
7.Long service life and high reliability.
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