Atherm bellows compensate for temperature changes

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Abssac has recently designed and manufactured a bespoke atherm temperature-sensitive bellows assembly for a customer in the defence industry.

Atherm bellows compensate for temperature changesAbssac reports that it has designed and manufactured a new atherm temperature-sensitive bellows assembly. Developed as part of the company's controlled electroform component programme, the assembly is said to be unique. Furthermore, the customer benefited from Abssac's sub-assembly service, thereby saving component costs and lead-times, yet without compromising quality in any way.

Services available from Abssac include soldering, induction brazing, electron-beam welding and adhesive bonding. Evacuated assembly, hermetic sealing and back-fill operations enable precision temperature- and pressure-sensitive devices to be produced to order.

For the atherm temperature-sensitive bellows assembly, Abssac's sub-assembly capabilities were combined with leading-edge technologies. The result is a lightweight, extremely sensitive unit featuring thin-walled, electrodeposited nickel bellows soldered to custom end pieces. Each sub-assembly is filled with a working fluid (with a known coefficient of thermal expansion) and finally sealed.

By sealing a specific volume of fluid within a electrodeposited nickel bellows, the volumetric thermal expansion characteristic of the fluid is transformed into a precise, measurable linear movement. This movement can be used as an actuator, or calibrated to be read as control data, and is completely reversible due to the extremely low hysteresis of the bellows material.

These athermalisation bellows assemblies are designed, manufactured and assembled to the customers exacting specifications. They are currently being used in a defence application to compensate for the thermal expansion of components within precision targeting devices. The response of the bellows ensures that the targeting image is not distorted by environmental changes in temperature from sub-zero to extreme desert heat conditions.

Follow the links for more information about Abssac's custom electroforms.

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