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For industrial applications involving the transfer of caustic, hazardous or noxious liquids or gas, it is vital to mitigate the potential for dangerous leaks or spills during operation. Stein Seal offers expert construction of mechanical seals, including the bellows seal, designed to prevent such leakage during industrial processing.

Stein’s metal bellows seals are a series of precision-engineered flexible, nested convolutions alternately welded at their inner and outer edges. The flexible convolutions act as a leak-tight seal, effectively separating two environments from one another.

The flexible convolutions perform multiple functions: They act as a spring assembly keeping the seal face and mating ring in contact with each other during operation while also acting as a sealing element to prevent leakage during shutdown periods.

These versatile seals can be used in various industrial applications and are designed to compress, extend, and absorb axial and angular movement while providing optimum sealing capacity.

The bellows forms a hermetical seal as well, preventing leakage of liquid or gas, even when subjected to extreme changes in temperature. This is one considerable advantage the bellows seal offers over the standard spring-loaded package seal. Another advantage is the ease with which a bellows seal can be installed or removed.


  • Act as a static barrier during shutdown conditions
  • Require low spring tension to compress the bellows
  • Operate under a wide range of temperatures
  • Possess high-strength characteristics
  • Perform well under high-temperature operation
  • Offer long service life
  • Minimize shaft damage
  • Are not subject to O-ring drag that affects many pusher seals
  • Produce even face loading, superior face tracking and reduced frictional heat build-up
  • Form a frictionless secondary seal when used with other seals
  • Supply axial springing that allows the bellows to operate over an extended axial length
  • Are pressure-balanced under actual design operating pressures to ensure consistent performance


Stein can supply bellows seals with a range of sizes and materials, stainless steels, high-nickel alloys, titanium or others to meet the operational conditions.

Selecting the proper seal for your application requires consideration of many variables, including the properties of the fluids or gasses being processed, their volume and velocity; operating conditions, including pressure and temperature ranges; potential hazards for health and the environment.

Bellows Seals from Stein Seal

  • Toroidal, coned, nested ripple, rippled, cantilevered, flat cantilevered
  • Shaft rotation speeds up to 500 ft/s (152.4 m/s)
  • Temperature ranges up to 800° F (400° C)
  • Delta pressure ranges up to 220 psi (1,500 KPa)
  • Diameters range up to 24 in. (60 cm)


Stein Seal bellows seals are generally paired with face seals for gas or liquid applications characterized by highly toxic, corrosive, high-temperature and high-pressure environments. Bellows may be machined or either hydroformed or welded using Inconel®, titanium or 300 stainless steel.

Typical applications include:

  • Cryogenics
  • Heat-transfer fluid
  • Chemicals and corrosives
  • Turbo Pumps
  • Coolant Pumps
  • Valves
  • Process Centrifuges
  • Compressors
  • Expansion Joints
  • Gearboxes