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New High-Pressure Lip Seal Technology

Lip seals are commonly used in applications that use process fluids including, asphalt, caustics, chocolate, adhesives, polymers, latex, fuels, oil, molasses, varnish, soaps, syrups, and resins. These applications can be some of the most difficult in terms of pump sealing. Viscous fluids tend to crystallize and create abrasive particles, which is why lip seals are employed rather than face seals in these situations. Until recently, lip seals were used to seal low pressures (7-psi to 10-psi), however new technology of lip seals allows for sealing 150-psi or greater on rotary equipment. Many advancements have been taking place in regard to the sealing material industry in the last several years, and this new technology is part of that evolution.

Photo Courtesy of Allied Metrics Seals & Fasteners, Inc

New designs for lip seals have dimensionally stable sealing elements with only one moving part (the seal/pump shaft). These seals also do not have springs, which can clog. Also the sealing element prevents product from getting between the dynamic and stationary sealing surfaces. At the tip of the sealing element there is a positive seal. A smooth hard-face coating on the shaft sleeve prevents excessive frictional heat. It is important for sealing materials to have good lubricating qualities as well as to have chemical resistance and good recovery characteristics in a wide temperature range. These recovery characteristics can be evaluated by inspecting how closely the sleeve is gripped by the lip seal when the shaft is turned. If it is loose or easy to turn, the lip seal will most likely leak at low pressure.

Photo Courtesy of Grumen Manufacturing

Another aspect to keep in mind when it comes to high-pressure lip seals with new dimensionally stable sealing elements is that these are quite sensitive to radial shaft movement. This means it is important to make sure that the shaft is stable and that the seal is mounted to the equipment completely concentric and square to the shaft. Installing seals correctly can make a huge difference in regards to its working life. For more information about lip seals and high pressure technology, contact a manufacturer near you today.