Metal Bellows

Flexibility and tightness at the highest level of precision

BOA metal bellows are produced from ductile metallic materials.

Comparison between edge welded and hydroformed bellows
Cross section of BOA bellows types

The BOA Group offers two different kinds of metal bellows:

  • Edge welded bellows and
  • Formed bellows

The basic element for formed bellows, a thin-walled cylindrical tube, is formed into corrugations using hydraulic or mechanical pressure. Different procedures and corrugation geometry are adopted depending on the production quantity and application.

Edge welded bellows are manufactured with individual metal diaphragms that are welded together.

BOA Metal bellows

Whether formed or edge welded, BOA metal bellows:

  • are extremely flexible,
  • have a long life expectancy,
  • do not need any maintenance,
  • are resistant to pressure and to temperature,
  • are vacuum-tight.

BOA metal bellows are typically used as:

  • shaft seals of valves
  • vibration absorbers in laser systems
  • volume compensators in transformers
  • actuators in measurement and control applications
  • flexible connection between solar panels
  • sealing or ducting elements in vacuum applications
  • temperature sensors
  • surge arrestors
  • reservoirs to store fluids
  • pressure sensors
Hydrofomed copper bellows
Welded metal bellows

Characteristics of BOA formed bellows:

  • single or multi-plied
  • offer considerable axial, lateral or angular movements
  • diameter 6 to 2100 mm
  • can have special coating (cu, au) and surface finishing
  • made from special materials like titanium, NI-alloys
  • special thermal treatment’s

Characteristics of BOA welded bellows:

  • single or multi-plied
  • diameter 6,4 to 584 mm
  • almost unlimited span (distance ID to OD)
  • compressible to solid height
  • have a much longer stroke per convolution
  • can be made of any rollable, weldable metal
  • extremely low spring rates possible
  • resistant to nicks and dents
  • high degree of translational & arcuated motion
  • diaphragms: wide thickness range

BOA Engineering

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Data Sheets Metal Bellows