Bellow sealed valves are a new type of Industrial Process valves. These valves are popular due to the leakage free performance hence, called “Zero Leak Valves” or “Emission Free Valves”.
With the application of Bellow seals the gland packing is supplemented by a metallic Bellow cartridge. One end of the Bellow is connected to the valve bonnet and the other end to the stem. The bellow movement is in one plane as the stroke in the valve takes place. With no rotational movements involved the fluid gets sealed to a very high degree. The fluid flows through the bottom part of the valve as per the stem movement takes place. Due to the bellow covering the stem the seal does not contact the stem at all. As the stem is the moving part in the valve it is the source of leakage due to the wear and tear of gland packing. Due to this shielding of the stem by the bellow the valve operated in a leak free zone.
The life cycle of the metal Bellow is largely dependent on the process of bellow manufacturing. At Pliant Bellows we manufacture them by hydroforming process. The properties achieved by the hydro forming process are far superior as compared to other process like, diaphragm welded bellows or mechanically drawn bellows. It is extremely important that the bellows have the mechanical and metallurgical properties for long cycle life of an bellow to avoid