Spring lip seals have been used for many years. Spring lip seals are used in a manner similar to conventional elastomer seals, such as o-rings. Elastomer seals often fail due to conditions that often occur in their operating environment, such as chemical corrosion, extreme high or low temperatures, extrusion, friction, or compression set. However, spring lip seals have different structures and do not work like conventional elastomers to avoid the cause of such seal failure. These spring lip seals include a jacket made of a high-performance polymer that is associated with a metal spring or similar device. These seals are suitable for various applications, such as rod and piston seals, face seals, and rotary shaft seals.

The basic spring lip seal design has two components: a U-shaped jacket made of high-performance polymer sealing material and a metal spring loading device. The U-shaped jacket is actuated by pressure, so that the fluid pressure of the fluid contained in the seal element energizes the sealing lip, forcing the sealing surface of the lip against the mating hardware. As the fluid pressure increases, the load on the sealing lip also increases to enhance the final seal contact. The jacket is machined rather than injection molded, so the outer contour of the seal can be easily enhanced for a specific surface contour. Thanks to polymer materials and machined jackets, these spring lip seals are suitable for almost any application.

The spring of the spring energized seal is arranged in the jacket to provide the offset force to the sealing lip. Springs are usually stainless steel. When the fluid pressure is insufficient to offset the sealing lip, the spring provides all the load required to offset the sealing lip to the surrounding hardware. In addition, the spring compensates for variations in the gland tolerance and normal wear of the seals. As a seal loading device, metal springs are more accurate than other devices used to control friction, such as elastomer O-rings. Three types of metal springs are commonly used: cantilever springs, canted coil spring, and helical springs. The load rating of the springs required for a particular application can be adjusted according to the linear friction or torque requirements of the application.

The jacekt material has several typical characteristics: low friction, high speed use, general chemical compatibility, low and high temperature capacity, high pressure rating and permanent elasticity, anti-aging, corrosion and compression permanent deformation. There are several types of polymers that provide these properties: polytetrafluoroethylene (PTFE) resin, other fluoropolymers such as ethylene/tetrafluoroethylene (ETFE) copolymers, thermoplastic elastomer (TPE) compounds, ultra-high molecular weight polyethylene (UHMWPE) compounds, and high modulus thermoplastics such as polyetheretherketone (PEEK).

However, in applications where corrosive media exist near the seal rings, even the highest quality stainless steel may be corroded. If the material of the spring deteriorates to the extent that it no longer contributes to the sealing of the seal ring, seal failure may occur. Corrosive environments are similarly destructive to elastomer materials. Although it is known that springs are embedded in elastomer seals to retain the springs, this method only provides edge protection for corrosive environments. In addition, embedding springs in the polymer will limit the effectiveness of the springs, and will require polymer seals to be manufactured by injection molding rather than more precise processing and manufacturing methods.

Therefore, a more effective corrosion environment seal is needed.