Edge-welded metal bellows assemblies for vacuum applications and other extreme environments.

Flexaseal’s edge-welded bellows technology is suited to many types of hermetic bellows applications. Whether the equipment is downhole lifts, filter dryers, actuators, wafer lifts, or valves our hermetic bellows designs are custom engineered for high cycle life.

Hermetic Bellows


  • Bellows core diameters from 3/4″ (20mm) to 7 1/8″ (181mm).
  • Customized flange / end fittings designed and manufactured in-house.
  • Personal design engineering support from inquiry to installation.
  • Helium mass spectrometer used for precision leak testing.
  • Superior delivery lead times.



Bellows: AM350, Hastelloy® C (various grades), Inconel® (various grades), Titanium (various grades), Monel. Double-ply and heat-treated bellows core options also available.
End fittings: 316 SS, Hastelloy® C (various grades), Inconel® (various grades), Titanium (various grades), Monel.

Note: Other materials available upon request.


Downhole (Artificial) Lift is the process of increasing the pressure within an oil well’s reservoir to move the oil to the surface.

Filter Dryers require a gas-tight seal when used in conjunction with CFC and HCFC refrigerants.

Freeze Dryers which conduct lyophilization (cryodesiccation) in vacuum environments with high purity standards.

Compressors can utilize hermetic bellows valves to eliminate leakage past dynamic seals. Compressors can also use valve stem seals when there is a need to hermetically contain the shaft while allowing for axial shaft movement.

Hermetic bellows devices have been used to prevent cavitation in Volume Compensators when the system’s positive pressure must be maintained during any volume fluctuations.

Hermetic bellows can act as a piston in hydraulic or pneumatic Actuators to transform pressure to linear motion. They are particularly effective in high-pressure applications where a dynamic seal could fail.

Vibration Dampers may employ hermetic bellows to isolate vibration.

Semiconductor and Aerospace technologies utilize extreme vacuum systems which may incorporate manipulators or linear translators, corrosive chemical washes, high-energy plasma etching, wafer production, and intense electromagnetic radiation in their manufacturing processes. Most of these activities take place inside sealed areas called clean rooms with hermetic equipment to drastically minimize personal and environmental exposure.

Hermetic bellows devices provide a layer of environmental protection when handling certain Energy Generation operations – including radiation, toxic emissions, and carcinogenic by-products. Hermetic bellows are also used in sealing scenarios involving extreme pressures and temperatures.

Hermetic bellows devices are necessary in Pharmaceutical Processing when biohazards materials must be contained and micro – contamination must be eliminated.

Quote Request

Depending on your specific needs and application, Flexaseal can help you identify the ideal products. Contact us to tell us about your needs and request a quote.