Extranet Lidering

Home > Blog > Product > Advantages and types...

Advantages and types of metal bellows mechanical seals

sellos mecánicos para la industria

Often, work conditions under which a sealing system must function can be very demanding: high pressures, extremely elevated temperatures, paste-like or chemically corrosive products, high frequency and intensity vibrations, etc. In the face of extreme conditions, a peak performance sealing system is required, such as our range of metal bellows mechanical seals.


These kinds of seals characteristically have a metal bellows instead of a spring/springs in order to maintain the strength between friction faces. Metal bellows present some advantages in relation to conventional spring systems (simple springs, multisprings or wave springs):

  • · Increased capability to respond to fatigue induced by continuous work cycles.
  • · The special alloy used for its fabrication provides it with a great chemical resistance and high temperature endurance, thus allowing the seal to uphold its performance under these circumstances
  • · Metal bellows keep the seal balanced, which enables it to work under pressures reaching 20 bar or at high revolutions, even going up to 6000 rpm without suffering premature wear.
  • · “Self-cleaning” ability thanks to its exterior shape, which generates a radial repelling effect when turning, preventing paste-like fluids to accumulate and solidify in the mechanical seal chamber.



The LMB85 model is a metal bellows mechanical seal capable of working in high temperatures, up to 300ºC, depending on the materials used on its friction face as well as its O-rings. The O-rings housing makes it static, avoiding possible damage caused by vibrations and repetitive changes in pressure. This mechanical seal has numerous applications, but is mainly used in:

     -Chemical industry, because it is ideal to work with heated oils 
     -Industrial refrigeration, since it can be found in many compressors


This model, the LMB84, is a modified version of the LMB85 in which the metal bellows is undulated. This characteristic allows for a greater ability to repel paste-like fluid and residues, compared to that of the conventional metal bellows. It is used in:

     -Food industry, because it works well with food pastes, caramel, chocolate, etc. 
     -Chemical industry, since it performs well with adhesive, melted plastics, etc.


The LMB86 metal bellows mechanical seal model is different to the aforementioned seals because it uses a special Grafoil wedge in order to seal the contact with the shaft, instead of using an O-ring. This is possible because of the press attached to its rear. Said system enables the seal to work in extreme temperatures not any other elastomers can handle, around 400ºC. Due to this ability, this seal is commonly used in the oil industry, where some processes are carried out at such high temperatures.

Contact our professional team so they can advise you