Introduction

high-voltage-feedthrough vacuumVacuum Feedthroughs are components which allow a connection between a vacuum filled chamber and the dry atmosphere outside. Electrical Feedthroughs allow current and/or voltage to pass into vacuum environments without loss of pressure. Fluid Feedthroughs allow gases or coolants to flow into vacuum environments.

Electrical Feedthroughs

Coaxial Feedthroughs are feedthroughs with two concentric conductor pathways. One cylindrical conductor path enclosed by and concentric with an outer metal shield path. The two paths are insulated and separated by a high purity alumina ceramic dielectric.

power-feedthroughs vacuumPower Feedthroughs allow high voltage, high current, or both to be transmitted. These feedthroughs can be used in applications such as electron-beam evaporation, DC plasma sputtering, and other coating applications, as well as vacuum furnaces. The ceramic can either be made very long, if space is available, or it can be made with many overlapping coils to save space. The smaller convoluted ceramics are preferable for environments where moisture or surface contaminants may restrict electrical performance of the regular long insulator. Ceramic surfaces on the air-side are usually coated with glass to make the surface smoother, and also reduce surface contamination which enhances the insulator. Some power feedthroughs can transmit coolants and power at the same time. The components should be close looped grounded systems and/or the coolants used should be either ethylene glycol or deionised water. These water cooled feedthroughs can carry higher current loads than regular ones of equal size.

Fluid Feedthroughs

General Fluid Feedthroughs are designed to allow water as a cooling medium to travel into a cavity under vacuum. These Feedthroughs are an inexpensive way to allow cooling water to enter a vacuum system. These components are available in different types of tube endings, eg Swagelok® and VCR®.

Cryogenic Fluid Feedthroughs are specifically designed to allow liquid nitrogen as a cooling medium to travel into a cavity under vacuum. Because of the extremely cold temperatures of liquid nitrogen, these feedthroughs are made with dual and coaxial geometries. The coaxial space within these tubes is oriented on the vacuum side of the feedthrough and provides a thermal shield which prevents most condensation and buildup of ice on the atmosphere side of the feedthrough. This is because ice buildup around the flange could cause the seal to lose integrity and the overall system to lose pressure.

AVT Services Pty Ltd are the official agents for MDC and ISI which produce electrical and fluid feedthroughs with the highest of quality ceramic to metal bonds, and which are delicately made and tested ensuring the non-compromise of low pressure chambers to atmospheric leakage. Please Contact us for more information regarding these and other vacuum products.