News | October 5, 1998

Furon's Rebuildable Lip Seal Reduces Replacement Costs up to 75%

 

By Angelo DePalma

"When you get a flat tire you don't junk your car, do you?" That was the analogy used by Jim Goodman, senior design engineer at Furon Co., to explain the difference between conventional lip seals and Furon's new OmniLip-RS. According to Goodman, OmniLip is the first completely rebuildable lip seal that features easily disassembled case construction for simple replacement of the inner sealing elements.

"What makes the OmniLip-RS unique is that it can be rebuilt without removing it from its seal housing, and at a fraction of the life-cycle cost of a standard throwaway PTFE lip seal," stated Goodman.

"Typical metal case seals are used in rotating applications. In a standard installation the metal seal housing presses into the equipment housing, usually to seal liquids in or out. So the dynamic sealing is occurring where the seal is in contact with the rotating shaft. When the seal is worn or starts to leak, you need a pulling tool to pull the seal back out. Be cautious, it is possible to scratch the housing, which will then require servicing, while pulling. Even if everything goes perfectly the process can take several hours.

"Our rebuildable seal installs in minutes using a simple allen wrench, which we actually provide with the part. When the seal is worn you take the housing apart, unbolt the seal housing, take out the old part, put in the new sealing component, bolt it back down, and that's it. You don't have to take the housing out ­ it's installed for the life of the equipment. Our PTFE seals are, of course, more expensive than elastomer seals, but you only have to purchase the seal body once, which means you save up to 75% of the cost of an entire seal assembly, depending on the configuration."

Capabilities and Applications

The OmniLip-RS comes in standard sizes and can be custom-designed for sanitary operation. Customers can choose the diameter size, the material for the outer seal case, whether to use one or more PTFE or PTFE blend elements, and what the inner seals are made of, such as glass- or carbon-filled seals.

The OmniLip-RS patent-pending design has a number of advantages compared to conventional elastomer lip seals it replaces. For example:

  • runs dry or with limited lubrication
  • works to temperature extremes from -66º to 450º
  • handles vacuum pressures in excess of 500 PSI
  • broad chemical resistance
  • capable of surface speeds up to 7,000 feet per minute
  • can be designed in a wide range of seal case materials, including carbon steel, stainless steel, aluminum, hastelloy, elgiloy and inconel.

The OmniLip-RS is primarily used in applications with shaft sizes from 2 to 20 inches. The rebuildable lip seal is excellent for use in mixers, hydraulic motors and pumps, chemical pumps, blowers, robotics, pharmaceutical and food processing equipment, vacuum pumps, and crankshafts of engines and compressors.

In a recent oil sealing test at 275ºF, the OmniLip-RS was compared to identical conditions with fluorocarbon elastomer seals. The elastomer seal began to leak oil after 50 hours of operation and allowed 76 ml of oil leakage after 100 hours, when the test was terminated. The OmniLip-RS outperformed the standard seal for twice as long with no leakage.

In another controlled test, a common elastomer seal was compared with the OmniLip-RS while running dry at 3600 rpm. Operating temperatures at the shaft were significantly lower with the rebuildable seal versus the elastomer seal. At higher pressures, the temperature differential between the two types of seals became even greater.

For more information contact Jim Goodman at 714-688-2635 or 800-544-0080.