All You Need To Know About Metal Bellow Mechanical Seal

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All You Need To Know About Metal Bellow Mechanical Seal

Metal bellows sealing technology has become popular in recent years. It is being used in several sealing technologies, e.g., corrosion-resistant sealing, high-temperature sealing, non-contacting gas, etc. In applications where you need to pump the liquid from one part to another by high extremes of temperatures, the best method is to use Metal Bellow Mechanical Seal.

When they are fitted with stainless steel end fittings, these seals can be used in high-temperature environments. They can be used beyond the range of mechanical seals with synthetic rubber sealing members.

Applications of these seals include heat transfer fluids, cryogenics, and severe chemical, and corrosive conditions. They can be used in the temperature range of -200 degrees Celsius to 350 degrees Celsius with standard seal construction.

What is a metal bellows seal? It is made through stamping disc-like plates that are contoured and welded in pairs at the inner diameter. Thus, separate convolutions of the bellows can be formed. It is the reason this Mechanical Seal is widely useful.

When several convolutions are stacked and welded at the outside diameter in the seal, then it is called a bellows capsule. The assembly is finished with a suitable end-fitting.

Also Read: All You Need To Know About Rubber Bellow Mechanical Seal

Design features of Metal Bellows Mechanical Seals

1. It serves a wide range of applications, from cryogenics to heat transfer liquids and corrosive chemicals.

2. It has a long service life; it is because there is only one moving part into it.

3. By flexible bellows construction eliminates seal hang-up due to solids or dirt in pumpage.

4. Mechanical seal wedge removes temperature restrictions of plastics or elastomers.

5. Built-in hydraulic balance removes a step-in shaft or sleeve.

6. They are available for either inside or outside mounting.

7. Stabilizer tabs prevent possible damage to the metal bellows due to vibration and excessive shaft runout of the shaft.

Which factors should be considered while picking Metal Below seals?

When you choose Metal Bellow Mechanical Seal, it is essential to keep the following factors in mind.

Shape of plate

The shape of the plate determines the stroke and flexing of a seal. If the configuration is nesting ripple, then the plates are contoured. Thus, when you compress them, they nest well. The ability of a seal to withstand high pressures depends on the contours and shape of the plate.


When bellows have straight flat segments, they offer less reliable weld joints. When the bellows axis is tilted, the stress at the welds and heat-affected area reduces.

Studies say that when the tilt is 45 degrees, the reliability and rigidity of the plate improve. Also, fatigue reduces.

Thickness of plates

Thin plates have a lower face load and less heat generation. Thus, you get long seal life. Thick plates are prone to metal fatigue.

Pressure and seal balance

The seal should be capable of handling the reverse pressure. For that, there should be a proper seal balance.

Plate span

A narrow plan gives higher stability under pressure.

Face width

When the face width is kept narrow, there is a lower heat at the seal faces. Due to that, face stability improves.

Also Read: Best Mechanical Seals Manufacturers in India

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