feedthroughs

Feedthroughs are components that allow a barrier, such as a wall of a chamber or enclosure, to be crossed without compromising the barrier’s essential properties. They are designed to convey electrical conductors, fluids, or gases from one side to the other while maintaining environmental isolation, mechanical support, and, where required, hermetic sealing.

There are several main types. Electrical feedthroughs carry electrical signals or power through a barrier and may be single-wire or multi-pin. Vacuum feedthroughs are designed to pass electrical or mechanical connections into vacuum or ultra-high vacuum systems and often employ hermetic seals. Fluid or gas feedthroughs transmit liquids or gases through a barrier, typically with seals to prevent leakage. Depending on the application, feedthroughs may be hermetic, achieving a leak-tight seal, or non-hermetic, using gaskets or elastomer seals.

Construction and materials vary with purpose. A typical feedthrough consists of a conductive element surrounded by an insulating material such as ceramic, glass-ceramic, PTFE, or other polymers, all enclosed in a metal shell. Hermetic feedthroughs use brazed or glass-sealed joints to achieve leak-tight performance over specified temperature and pressure ranges. Non-hermetic variants rely on elastomeric seals and are not designed for high-precision leak prevention. Materials are chosen for electrical, thermal, and chemical compatibility, and for the required pressure, temperature, and environmental exposure.

Applications span scientific instrumentation, vacuum and cryogenic systems, power electronics enclosures, automotive sensors, and medical devices. Key design considerations include electrical rating, dielectric strength, leakage rate, mechanical robustness, and compatibility with the environment. Standards and testing procedures vary by application and typically address leakage, dielectric withstand, thermal cycling, and pressure limits.