Energized seals (lim seal) are sealing systems which consist of a jacket in thermoplastics (PTFE, PE, PEEK) and an internal spring in a corrosion-resistant metals (stainless steel, Inconel, Elgiloy ®, Hastelloy®). They are suitable to ensure the seal both in static and in dynamic applications (linear or rotary movement) and are not subject to aging, as instead happens to all the seals made of elastomeric material. When the energized seal is mounted, the spring is compressed and pushes the lips of the jacket against the groove walls, thus ensuring the seal.
The spring is a crucial element, because it provides the permanent elasticity of the jacket and compensates for wear, eccentricities and misalignments. The load of the spring may be provided, for example, to generate a very low friction (dynamic applications) or a very high load (cryogenic applications). LIMA manufactures several profiles of energized seals, many of which may also be fitted interchangeably in the same housing.
There are plenty of applications that require the use of energized seals and include: hydraulics, pneumatics and aircraft conditioning, vacuum technologies, drilling systems, laboratory equipment, machinery for the food industry, for dosing systems and filling, compressors, medical instrumentation, pumps, infrared systems, gas turbines, diesel engines, petrochemical plants, couplings and rotary joints, missiles and spacecraft, cryogenic plants, extruders for plastics, turbine engines, valves, control systems fuel, robots, equipment for the production of semiconductors.
The choice of the most suitable material depends from the application criticality. Here are the most popular materials and they features:
PTFE + carbon-graphite
PTFE + glass + MoS2
PTFE + bronze + MoS2
PTFE + carbon fiber