Spring energized seal is a spring-actuated, pressure-assisted sealing device consisting of a PTFE (or other polymer) jacket partially encapsulates a corrosion-resistant metal spring energizer.

When the JST seal is installed in the gland, the spring is under compression, forcing the jacket lips against the gland walls and there by creating a leak-tight seal. The spring provides permanent resilience to the seal jacket and compensates for material wear and hardware misalignment or eccentricity. System pressure also assists in energizing the seal jacket. Spring loading assisted by system pressure provides effective sealing in both low and high-pressure operating environments.

JST jackets are precision machined from PTFE and PTFE fillers. An seal with a PTFE jacket functions at temperatures ranging from cryogenic to 572F(300C) and is inert to virtually all chemicals except molten alkali metals, fluorine gas at high temperature and chlorine trifluoride(CIF3).

JST Seals products are available with a variety of spring energizers, each with characteristics that meet specific requirements. Spring loading can be engineered to meet critical low friction requirements in dynamic applications, or extremely high loading often required for cryogenic sealing. Springs are fabricated from corrosion-resistant metals such as stainless steels, Elgiloy, Hast Alloy etc., products with metal springs have unlimited shelf life and are not subject to age controls normally imposed on elastomeric seals.