The welded bellows in the metal bellows mechanical seals not only has the effect of tension spring, but also has a sealing structure. Therefore, the design does not need a moving ring O-ring, while the effect of tension spring in the general mechanical seal (push ring type) is only to maintain the compression and balance of the friction surface. Compared with general mechanical seals, metal bellows mechanical seals have many advantages, which can be summarized as follows.
1. High precision: the welded bellows has the effect of tension spring and is a combination of countless tension springs, so it solves the problem of general tension spring deformation due to centrifugal force, rotates at an appropriate height, and the sealing surface is pressed evenly.
2. Good oscillation resistance and flexibility: the bellows has high flexibility and good absorption effect on oscillation, so it has high habit ability of radial runout, axial clearance, oscillation and swing to avoid leakage.
3. Simple structure: simple structure and easy assembly. Unlike the tension spring seal, which is composed of many parts, the use is complex.
4. Adapt to a variety of temperature conditions: the welded bellows has a small coefficient of thermal expansion and can be used at low or high temperature. And there is no o - ring disjoint temperature limit, the design is more comfortable
5. Adapt to high pressure: due to the balance effect of the bellows itself, the sealing surface area can be adjusted to offset the fluid pressure, reduce the friction of the sealing surface, and then reduce the amount of heating and wear. It can be applied to high pressure.
6. To protect the machine: the mechanical seal of welded bellows has no O-ring, so the wear of shaft or sleeve caused by the abrasion of O-ring will not occur. It has the effect of protecting the shaft, so there is no need to install the shaft sleeve.
7. Habitual corrosive fluid: the welded bellows is made of highly corrosive Hastelloy 276 and other materials to avoid the corrosion of tension spring and O-ring, so the sealing is completed.
8. No suspension: using the general push ring mechanical seal, a small amount of leaked fluid solidifies and deposits in the air to prevent the movement of the moving ring O-ring. Therefore, the adhesion force of the sealing end face becomes weak or disappears, and then leads to leakage. The mechanical seals of welded metal bellows has no O-ring, which will not be affected even if there is solidified material. It can rotate safely and extend its service life.
9. Screw pumping effect: the bellows itself has screw pumping effect, which can effectively correspond to the fluid containing solid particles and help flush.
