Bellow Valves
Bellow Valve is gate or globe valve that uses a cylindrical metal bellows to hermetically seal the valve against stem leakage.
How bellow valves work
Bellow is similar to a hollow flexible hose. It functions like a vertical diaphragm . It seals with the valve stem at one end, and seals with the valve body at the other end. Therefore, it allows a small relative move between valve stem and body, but prevents fluid from leaking across bellow surface. The move pushes seat or stem tip for valve to close or open.
Applications
Heat transfer media
Hot oil is commonly used in industries such as synthetic fibres . However, there is always a risk of fire due to hot oil spillage on highly inflammable chemicals. Here, bellow Valves can stop the leakage.
Vacuum or ultra high vacuum
Some applications require a vacuum pump to continually extract air from a pipeline. Any conventional valves installed on the pipeline can allow external air to enter the pipeline thorough the valve stuffing box. Hence the bellow seal Valve is the only solution to prevent air from passing through the stuffing box.
Highly hazardous fluids
For media such as chlorine , hydrogen, ammonia and phosgene, the bellow valve is an ideal design as leakage through the gland is totally eliminated. Nuclear plant, heavy water plant: in instances where radiation leakage is to be prevented at all times, the bellow valve is the ultimate choice.
Costly fluids
In some applications leaks need to be avoided simply because of the high cost of the fluid. Here, an economic assessment often favours the use of bellow valves.
Environmental standards
Around the world, standards regarding emissions and the environment are getting more stringent day by day. It can therefore be difficult for companies to expand within existing premises. With the use of bellow seal Valves, expansion without additional environmentaldamage is possible.