Swing-type CHECK VALVEShave been known for many years and are widely used in many industrial processes for preventing the backflow of liquid through a conduit. Generally speaking, such valves have been difficult to repair, frequently requiring replacment of an entire valve body when only a portion of the structure, such as the valve seat, becomes worn through use.

In view of the fact that swing Check Valves are desirably designed such that the valve can be used either in a horizontally extending conduit or in a vertically extending conduit, heretofore, the valve body usually is designed such that the disc will open through an angle of less than 90