Performance characteristics of metal bellows mechanical seal

The bellows is a sealing element that integrates elastic elements, auxiliary seals and torque transmission mechanisms (ordinary seals do not have this kinetic energy), and its torque method is unique to bellows mechanical seals. The end face has uniform pressure ratio, high temperature resistance and good followability. The moving ring does not have an auxiliary sealing ring, thus reducing one leakage point, reducing the frictional resistance of the moving ring, and improving the following performance of the moving ring.

Commonly used bellows are pressed and welded. Pressed corrugated pipes are made by elongating and forming thin-walled pipes on a press or using hydraulic molding; welded corrugated pipes are made by welding the inner and outer circles of film sheets (commonly used).

Compared with pressed corrugated pipes, welded corrugated pipes have the following advantages:

① Due to the large radial stiffness of the corrugated nodes and the variety of manufacturing materials, the range of pressure and temperature used for welded bellows is wide;

②Welded bellows can be used as springs with precise working characteristics;

③The twisting stiffness is large;

④ Longer fatigue endurance limit;

⑤Compact size.

Disadvantages of welded bellows: The welds of welded bellows are prone to fatigue damage; when the welded bellows is subjected to hydraulic force, the bellows produces axial displacement, causing its effective area to change, thereby changing the area ratio of the seal.