BELLOW SEAL VALVES
These Valves replace conventional Gland Packed Valves with a Bellows cartridge, which is welded with the Valve spindle/Plug at the lower side and stainless steel collar at the upper side. The stainless steel collar is held in between the body and bonnet male female joint with the fasteners.
The media flowing through the Valves is contained between the bellows and pressure envelope preventing any escape of media into the atmosphere hence all leakage ports through body, bonnet joints or glands are sealed to have ZERO LEAKAGE and Virtually Maintenance Free saving time and money.
FORMED BELLOWS are produced from a thin tube. The shaping of the metal is carried out in collapsible die under high fluid pressure. Because of wide opening between piles of Bellows, Bellows function will not be impaired by bits of foreign matter in fluid. Reliable and durable because Bellows are produced from a single piece of metal.
For handing higher pressures, multiply designs of bellows is recommended. The pressure that bellows withstand can be increased by using 2 or 3 plies of metal wall. A two-ply bellow can increase its pressure rating by 80% to 100% than single ply bellow of same thickness. Alternately, if single-ply bellow of thickness equivalent to pressure rating of two-ply bellow is used, the stroke length is reduced. Thus, multiply design offers distinct advantage over single ply thick bellow.
The components are joint by full penetration weld using MIG process. This ensures that full thickness is maintained so that there are no crevices, which might be under corrosion attack. In Bellows Sealed Valves then on-rotating stem mechanism is designed to prevent torsion loads on the Bellows assembly.
Secondary seal provides back-up protection; this eliminates any uncontrolled emission and prevents a catastrophic failure in the event that the Bellows did fail in the unlikely event of a fatigue failure with the advent of multi-ply bellows and exotic metals. Bellows Sealed Valves are now available in a wide range of materials, pressures, temperatures and sizes to extend the application range of hermetic stem sealing technology.