Metal Bellows Seals – Types and Advantages of metal bellows seals

Most often these types of seals are thought of as very high-temperature seals. But Metal Bellow Seals are often efficient in a huge range of other seal applications. Most usual of these is chemical and general water pump applications.

For several years in a cheap form of Metal Bellow Seals have been utilized very successfully in the wastewater, sewage sector and in the agriculture industries pumping irrigation water, these seals were normally made of formed bellows rather than a welded.

Welded Metal Bellow Seals are little stronger and have great flex and recovery characteristics which are more accurate to holding seal faces jointly but cost more to manufacture. Welded seals are less prone to metal fatigue.

Benefits of Metal Bellow Seals:

These sorts of seals characteristically have a Metal Bellow in its place of spring in order to keep the strength among friction faces. Metal Bellow Mechanical Seals present some benefits in relation to traditional spring system (simple springs, wave spring or multi springs).

  • Increased ability to respond to fatigue induces by regular work cycles.
  • Unique alloy utilized for its fabrication gives it with remarkable chemical resistance and very high-temperature endurance, therefore allowing this to uphold its performance below these situations.
  • Metal Bellows holds the seal balanced, which lets it work below pressure reaching 20 bar or at extreme revolutions, even going up to 6000-7000 RMP without suffering premature wear.
  • Self Cleaning capability thanks to its exterior formation, which generates a radial repelling effect when tuning, preventing some paste-like liquids to accumulate and solidify in the seal chamber.

Types of Metal Bellow Seals


The LMB85 type is a Metal Bellow Seals able for working in extreme conditions, up to 350ºC, all depending on the material utilized on its friction face as-well-as its O-Rings. The O-rings housing creates it static, avoiding possible harm reasoned by vibrations and repetitive alterations in pressure. The mechanical seal has several applications, but is mainly utilized in:

  • Industrial refrigeration, since it can be found in numerous compressors
  • Chemical industry, because it’s perfect to work with heated oils


This model of Metal Bellow Seals is a modified version of the LMB85 in which the Metal Bellow is undulated. This characteristic lets for a higher capability to repel paste-like residues and fluid, compared to that of usual metal bellows. It’s utilized in:

Chemical industry, since it performs fine with melted plastics, adhesive, etc.
The food industry, because it works really great with caramel, food pastes, chocolate, etc.


The MNB86 type Metal Bellow Seals model is different from the aforementioned because it uses a unique Grafoil wedge in order to seal the connection with the shaft, instead of utilizing O-ring. This is possible because of the press connected to its rear. Said system allows the seal to work in high temperature, not any other elastomers can manage, around 400ºC. Due to this capability, this seal is usually utilized in oil sector, where a few procedures are carried out at such extreme temperature.

In the face of higher conditions, speak performance sealing ecosystem is needed such as Leap Proof Seal range of metal bellows and mechanical seals.