With the rapid development of modern industry, there is an increasing demand for various types of pipelines. Among them, those pipelines that transport dangerous media such as flammable, explosive, or highly toxic have strict requirements on sealing leakage.
Ordinary packing seal valves are no longer suitable for applications in these hazardous situations. The bellows valve completely eliminates the possibility of leakage because of its mechanical hard seal.
What’s a bellows valve?
The bellows valve is a valve with a bellows as the sealing element between the valve stem and the valve body. It is often used on occasions with high temperature and high-pressure requirements.
The upper end of the bellows and the cap are welded together, and the cap is placed between the valve body and the valve cover. The lower end is connected to the valve stem by welding.
How does a bellows valve work?
Its working principle is to rotate the valve hand-wheel and drive the bellows to expand and contract through the up and down movement of the valve stem.
When closing the valve, turn the handwheel clockwise, the valve stem and the solid wedge at its bottom move downwards, tightly pressing the seal and closing the valve.
When opening the valve, turn the handwheel counterclockwise, the valve stem and the solid wedge at its bottom move upwards, slowly leave the sealing seat to open the valve.
Bellows valves not only increase the safety of pipeline equipment operation, but also provide a cleaner working environment. Compared with the shortcomings of fast aging of ordinary valve sealing packing, the use of bellows valve can greatly reduce the cost of maintenance and repair.
The maximum working pressure of the bellows valve depends on the compressive strength and fatigue strength of the metal material used in the bellows.
Commonly used types of bellows valves are bellows globe valves, bellows gate valves and bellows ball valves.
