Flanged gate valves is very common on pipeline. The opening and closing part of flanged gate valve is the wedge, the direction of movement of the wedge is perpendicular to the direction of the fluid, the gate valve can only be fully opened and fully closed. It's not for the used of adjustment. The wedge has two sealing surfaces, and the two sealing faces commonly form wedge shape.

Gate valve flange type flange is installed onto the pipeline by the flanges at both ends. This type of valve should generally be installed horizontally in the pipeline. When the gate valve is closed, the sealing surface can be sealed only by medium pressure, i.e. by pressing the sealing surface of the wedge to the seat on the other side to ensure the sealing is perfect.

The wedge of the resilient seated gate valve moves in a straight line with the stem.  If the stem moves up and down together withe the wedge, the gate valves is called OS & Y gate valve. If the stem keep the same position during close/open operation, the gate valve is called NRS gate valve.