Aneroid bellows assemblies are designed to convert changes in pressure into linear displacement. A bellows is a thin-walled convoluted tube that is leak-tight and can compress or extend axially along its convoluted length. When the bellows are assembled to end pieces that close off the ends, it will then respond when the pressure outside of the assembly is different than the pressure inside. The bellows assembly will react by extending or compressing in precise response to the differential pressure.


“As analog solutions in a digital world,” aneroid bellows can replace or back up electronic and digital sensors with no electricity needed. Our bellows are more customizable and create fewer potential points of failure.



  • Altimeters to help sense altitude changes
  • Aircraft fuel valves to modulate fuel mixture as atmospheric pressure changes due to altitude
  • Personal air tanks for HALO jumps to regulate air composition as pressure/altitude changes
  • Depth sensors in undersea applications (especially redundant sensors that need no electrical power)
  • Any application where the designer needs to actuate something in response to a pressure change



Stops – Some aneroids are “free” or unstopped, where the

assembly’s movement is not constrained by any physical feature.

It will respond freely and immediately to any change in pressure.

Others contain a stop, which restricts compression beyond a

certain distance.

Springs – Many aneroid assemblies include a spring in parallel

with the bellows. The bellows and spring each contribute to the

overall stiffness of the assembly.

Aneroid FAQ

Adjustment features – Sometimes a thread or a stud, is part of

the design. This makes it possible to preload the assembly in the

installation, allowing the user to “tune” its performance.