Patent Application
20160017890
The present invention relates to bearing isolators. Specifically, the invention relates to a disposable oil containment cup for use on a bearing isolator.
Horizontal bearing housings are often manufactured with lip seals that seal against stainless steel sleeves fitted to the bearing housing shaft. The stainless steel sleeves are typically chromed for hardness (and thus a prolonged operating life), and then ground to have no machine lead, a necessity to prevent leakage and also extend the lip seal life. These extra steps that prevent leakage, extend the operating life of the lip seal, and protect the shaft, add considerable cost to the bearing housing assembly. Further, lip seals will typically start leaking before the bearings need to be replaced, and replacing a lip seal requires a major pump teardown.
By contrast, the bearing isolator has several advantages over the traditional bearing housing sealing solutions, including lip seals and mechanical seals in non-flooded applications. The bearing isolator is a fraction of the cost compared to a chromed and ground stainless steel sleeve. It has also been found to consume less power and, without the similar wear issues of a lip seal, last forever.
The advantages of the bearing isolator stem from the fact that they are non-contacting, meaning the rotor is not in contact with the stator. Since they are non-contacting, bearing isolators (1) lower the energy costs of the bearing housing, and (2) have no parts to wear out. Lower parasitic pump losses mean lower energy costs which will increase the overall water to wire pump efficiency, and having no parts which will wear out increases reliability.
However, a problem with bearing isolators was found to exist when horizontal pumps are shipped fully assembled and filled with oil. As the packaged pump tips due to, for example, a carrier traveling up and down hills, the bearing isolator will become flooded and oil will leak through a path between the bearing isolator rotor and stator. This is undesirable from a safety standpoint (e.g., slipping, contamination) and potentially catastrophic if oil loss is undetected and enough is leaked from the assembly to cause premature bearing failure.
Until the invention of the present application, this problem was solved in other ways by those skilled in the art. The present oil containment cup provides an inexpensive solution which functions to prevent oil leakage during shipment of assembled pump systems having bearing isolators without sacrificing reliability or efficiency.
There is disclosed herein improved unique oil leak prevention device and method for a pump assembly which affords cost and operating advantages.
Generally speaking, the oil leak prevention device is for use on a horizontal pump assembly having a non-contacting bearing isolator. The device comprises a first annular surface having an inner edge defining a central opening and a second surface extending from an outer edge of the first surface. The second surface is configured to cover an outside leak path between the rotor and the stator of the non-contacting bearing isolator when the central opening is placed about the shaft of the pump.
In specific alternate embodiments, the second surface may extend from only a portion of the first surface or from the entire first surface. Likewise, the first surface may be a complete annular ring or a partial ring. Preferably, the second surface is normal (i.e., perpendicular) to the first surface.
In preferred embodiments, the first and second surfaces are comprised of a synthetic, oil-resistant, elastomeric material, such as nitrile rubber, fluoroelastomers (e.g., VITON®) or similar elastomeric material, for a good fit on the bearing isolator and resistance to typical oils.
As for the disclosed method for preventing the leakage of oil from a pump assembly having at least one bearing isolator comprising a stator, a rotor and a leak path between the rotor and stator, the leak path having an opening outside a bearing housing of the pump assembly, the method comprises the steps of first forming an oil containment cup having a first annular surface with an inner edge defining a central opening, and a second surface extending from an outer edge of the first surface, and then placing the oil containment cup in contact with the bearing isolator such that a shaft of the pump assembly passes through the central opening and the second surface of the oil containment cup covers the opening of the leak path. Preferably, the cup is removed from the pump before operation of the pump.
These and other aspects of the invention may be understood more readily from the following description and the appended drawings.
For the purpose of facilitating an understanding of the subject matter sought to be protected, there are illustrated in the accompanying drawings, embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated.
While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail at least one preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to any of the specific embodiments illustrated.
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In an alternate embodiment, only the containment surface 22 may be used to form an oil containment device. The device, similar to an elastic band, could be tension fit to the bearing isolator to cover the opening 19 with the containment surface 22. The positioning surface (i.e., first surface 20 in above embodiment) allows the containment cup to be more easily positioned and installed on the isolator.
Preferably, the cup 14 is made of a synthetic, oil-resistant, elastomeric material, such as nitrile rubber, fluoroelastomers (e.g., VITON®) or similar material, for a good fit on the bearing isolator and resistance to typical oils. The thickness of the first surface 20 and the second surface 22 is preferably about 0.040 inches (about 0.10 cm) using nitrile rubber material. The thickness may vary, of course, based on the diameter of the bearing isolator. The material is also preferably red in color to stand out from the other components of the pump system, and red is typically the color for warning labels. Other materials, colors and alternate thicknesses may also be suitable.
In alternate embodiments, the first surface 20 may comprise less than a full ring, as illustrated in
The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of applicants' contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.
