A "hermetic terminal assembly" is a simple device designed to supply electric energy through a hermetic (air tight) metal enclosure. These devices are sometimes also called "feed-throughs", "hermetic headers", and "terminal clusters". Vitrus' products are designed specifically to provide electric power to the motor inside Air Conditioning and Refrigeration (ACR) compressors.

These feed-throughs are resistance welded to the hermetic compressor housings, or bolted to semi-hermetic compressor housings. The hermetic terminal's electric conductor pins must be mounted in a manner that is not only hermetic, but also electrically insulated. Glass-to-Metal Seal is the core technology that provides these two critical properties.

Vitrus terminals' robust hermetic characteristics are achieved by combining two Glass-to-Metal Seal techniques. Steel and glass compositions are selected for thermal expansion properties in order to create a strong compression seal. Control of thermal and chemical atmosphere conditions during the sealing process creates a chemical bond between the glass and the metal components.

The basic electrical isolation of the conductor pins is provided by the glass seal. This is enhanced by application of a coating over the glass seals. Either a silicone film or an epoxy coating is used for this. Epoxy coatings can be extended beyond the glass seal surfaces, and are used to achieve the greater insulated distances required for higher voltage applications.

These and other characteristics engineered into the construction of Vitrus Hermetic Terminal Assemblies are illustrated below.