Globe valve and sealing ring

The globe valve, also known as the gate valve, is a mandatory sealing valve, so when the valve is closed, pressure must be applied to the valve disc to force the sealing surface not to leak.

The opening and closing parts of the globe valve are plug-shaped discs, the sealing surface is flat or conical, and the discs move linearly along the center line of the fluid. The movement form of the valve stem includes a lifting rod type (the valve stem rises and falls, and the hand-wheel does not rise and fall), and there is also a lifting rotary rod type (the hand-wheel and the valve stem rotate and rise, and the nut is arranged on the valve body). The globe valve is only suitable for fully open and fully closed, no adjustment and throttling are allowed. The globe valve is a forced sealing valve, so when the valve is closed, pressure must be applied to the valve disc to force the sealing surface not to leak. When the medium enters the valve from under the valve disc, the resistance that the operating force needs to overcome is the friction force between the valve stem and the packing and the thrust generated by the pressure of the medium. The force of closing the valve is larger than the force of opening the valve, so the valve The diameter of the stem should be large, otherwise the failure of the top of the valve stem will occur.

In recent years, since the emergence of self-sealing valves, the medium flow direction of the globe valve (the globe valve seal) has been changed from the top of the valve disc into the valve cavity. At this time, under the action of the medium pressure, the force of closing the valve is small, while the opening If the force is large, the diameter of the valve stem can be reduced accordingly. At the same time, under the action of the medium, this form of valve is also tighter. The closing principle of the globe valve is to rely on the pressure of the valve stem to make the sealing surface of the disc and the sealing surface of the valve seat closely fit, preventing the flow of the medium. The globe valve only allows the medium to flow in one direction, and has directionality during installation. The structural length of the globe valve is longer than that of the gate valve, and at the same time, the fluid resistance is large, and the sealing reliability is not strong during long-term operation.