In the process of production piping in the coal chemical workshop, the globe valve is often used. Let's analyze the working principle and operation of it. Let's take a look today.
Globe valve, also known as gate valve, is one of the most widely used valves. The reason why it is so popular is because the friction between the sealing surfaces during opening and closing is small, more durable, the opening height is not large, and the manufacturing is easy. Easy maintenance, not only suitable for medium and low pressure, but also suitable for high pressure. The shut-off valve is a force-sealed valve, so when the valve is closed, pressure must be applied to the clapper to force the sealing surface to not leak.
The working principle of the gost globe valve: The valve plays an important role in cutting off and throttling the medium in the pipeline. The globe valve is an extremely important cut-off valve, and its sealing is through the valve The stem applies torque, and the stem applies pressure to the valve flap in the axial direction, so that the sealing surface of the valve flap and the sealing surface of the valve seat closely fit together to prevent the medium from leaking along the gap between the sealing surfaces.
The forge steel globe valve seal consists of the valve disc sealing surface and the valve seat sealing surface. The valve stem drives the valve disc to move vertically along the center line of the valve seat. During the opening and closing process of the globe valve, the opening height is small, easy to adjust the flow, and easy to manufacture and maintain, with a wide range of pressure application.
Compared with another gate valve, one of the commonly used cut-off valves in industrial production, from the structural point of view, the globe valve is simpler than the former, which is convenient for manufacturing and maintenance. In terms of service life, the sealing surface of the globe valve is not easy to wear and scratch, and there is no relative sliding between the valve flap and the sealing surface during the opening and closing of the valve, so the wear and abrasion of the sealing surface is small, so the The service life cut-off valve has a small flap stroke in the fully closed process, and its height is smaller than other valves. The disadvantage of the globe valve is that the opening and closing torque is large and it is difficult to achieve rapid opening and closing. Because the flow path in the valve body is relatively tortuous, the fluid flow resistance is large, resulting in a large loss of fluid power in the pipeline.
For shut-off valves, not only installation and maintenance are required, but also operation.
1. The opening and closing globe valve should be stable and not impacted. Some parts of the high-pressure shut-off valve with shock opening and closing have considered that this kind of impact force can not be equal to the general shut-off valve.
2. When the globe valve is fully opened, turn the handwheel a little to tighten the threads tightly to avoid loose damage.
3. When the pipeline is initially used, there are many internal dirts. You can open the shut-off valve slightly, use the high-speed flow of the medium to flush it away, and then gently close it. Surface), turn it on again, repeat this many times, flush out the dirt, and then put into normal work.
4. Normally open globe valve, there may be dirt on the sealing surface. When closing, use the above method to wash it off, and then formally close it.
5. If the hand wheel and handle are damaged or lost, they should be equipped immediately, and can not be replaced by a live wrench, so as to avoid damage to the valve stem and the opening and closing failure, resulting in an accident in production.
6. Some media are cooled after the shut-off valve is closed, so that the valve parts shrink, the operator should close it again at an appropriate time, so that the sealing surface does not leave fine slits, otherwise, the medium flows through the fine slits at high speed, it is easy to flush Eroded sealing surface.
7. During operation, if you find that the operation is too laborious, you should analyze the reason. If the packing is too tight, it can be properly relaxed. If the valve stem is skewed, personnel should be notified to repair it. In some shut-off valves, when the closing part is closed, the closing part is heated and expanded, which makes it difficult to open; if it must be opened at this time, you can loosen the valve cover thread half a circle to eliminate the valve stem stress, and then pull the handwheel.