![]() ![]() The mean operating life of a lip seal is approximately 20% of the 8760 hours in a year, so that 20% of the yearly installation of lip seals is engaged with shafts and actually sealing at one point in time. Lip seals cannot tolerate shaft imperfections.įace seals also depend on a constantly replenished lubrication film between their optically flat sealing surfaces.Īn average of about 38 million lip seals are installed each year. Machining marks on the shaft can cause almost instant leakage into or out of the bearing enclosure (Fig. The shaft can be neither too rough nor too smooth. When the lip seal ceases to contact the shaft, its usefulness as a bearing and lubricant protection device also comes to an end.įor maximum performance, lip seals depend on a controlled oil film at the contact point between the sealing lip and the shaft. Power consumption, while the lip or face seal was sealing, was never thought to be important.Īccording to industry sources, the electric power consumed by contacting radial lip seals, and other contact seals, can be substantial.Īlthough a lip seal’s duration of contact with the shaft is short lived (the mean life is 1800 hr) it has frictional drag and an average power consumption rate of about 147 W. Grooving of the shaft by a lip seal can be repaired by installing a thin, specially made sleeve. Rarely would anyone rationalize the periodic change-out of a lip seal, since it was almost never done. Conventional wisdom points out that for the price of a labyrinth isolator, one could buy a dozen or so lip seals. Labyrinth isolators cost at least ten times more than a rubber lip seal, making whole plant conversions difficult to justify. With the exception of difficult-path, simple labyrinth isolators in API pumps and steam turbines, there was no known viable alternative to long-established methods of sealing bearing enclosures.Ĭompound labyrinth isolators function in place of a common lip seal and are non-contacting, non-wearing, and do not generate heat. In any event, the arguments are theoretical in nature and in practice the empirical data is at best inconclusive.īoth lip and face seals hermetically seal bearing housings for a time, but both are subject to wear and deterioration at a fraction of the design life of the bearings they are supposed to protect.Ĭompact, inexpensive face seals, sometimes powered by permanent magnets, were applied to pump bearing housings primarily because of their ability to hermetically seal the bearing environment (Fig. Labyrinth bearing isolators have been refined to the point of positively sealing while the equipment is at rest and dynamically sealing when the equipment rotates. Whether or not this degree of sealing is necessary is open to debate. Hermetic sealing is defined as an absolute prevention of voluntary transfer of air or vapor in or out of a bearing enclosure that can only be accomplished with a contact-sealing device. It is argued that only contact seals, including lip seals and face seals, are able to hermetically seal a bearing enclosure. ![]() We pride ourselves on designing the right seal for the right application so please feel free to contact us or head over to our website at David Orlowski, Inpro/Seal Co., Rock Island, IL. And, because it's liquid tight it makes it a great choice for very challenging lubrication environments like flooded conditions. It has a stainless steel and a soft compliant face that are both precision lapped and pulled together by a magnetic force.Īlthough it is a contact seal, the self-lubricating material on the soft face will give it an extremely long sealing life. The VBMag, our contact design, operates a little bit differently. ![]() There are some applications that will require a contact seal. ![]() Because it's non-contacting and totally non-wearing, it has an extremely long sealing life and makes it a great choice for the vast majority of our applications. Anything that tries to get into the bearing housing is going to come in through this pathway and, before it can get into the housing, it's going to be expelled through the bottom of the seal out the exposure port through gravity and centrifugal force. Our non-contact seals rely on a torturous pathway to create that ceiling interface. Let's first talk about the non-contact seals. Secondly, they both have the same main two components: a rotating element and a stationary element or a rotor and a stator. This will significantly prolong the life of your equipment and the life of your bearings. First and foremost, they have the same goal which is to retain lubrication and to exclude contaminants from entering your bearing housing. Broadly speaking those are non-contact compound Labyrinth seals and our contact bearing isolators. Hi, my name is Chris Solfelt with Inpro/Seal and today we're going to talk about the different types of bearing isolators that we make here. ![]()
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