Seal for a joint or juncture – Seal between relatively movable parts – Close proximity seal
Reexamination Certificate
1998-07-02
2001-11-06
Knight, Anthony (Department: 3626)
Seal for a joint or juncture
Seal between relatively movable parts
Close proximity seal
C277S412000, C277S419000, C277S420000
Reexamination Certificate
active
06311984
ABSTRACT:
BACKGROUND OF THE INVENTION
The prior art and description of these applications including the drawings and the resulting improvements are added herein for complete disclosure is shown in the original application. This further improvement is shown in newly submitted
FIGS. 6 and 7
and is the best mode now known.
The oil mist lubrication systems and the problems associated with the prior art still exist. The retention of the oil in the housing utilizing the oil mist system is novel. Prior art searches show no oil mist control systems which separate the mist after injection into the bearing housing to prevent escape of the mist into the atmosphere.
The oil mist coalescing system of this invention operates on the identical principles of the original disclosure and application, however, this best mode insures optimum drive engagement of the rotating member, desired coalescing action by controlling the engagement between the coalescing member and the rotating member, and by the ability to vary as necessary or desirable the amount of coalescing surface exposed to rotation and therefore utilize to the maximum the coalescing action.
Oil mist lubrication has been widely used in the Hydrocarbon Processing and Primary Metal industries as a means of delivering a constant supply of fresh lubricant directly to the bearings of various types in order to enhance the reliability of the rotating equipment.
Oil mist systems continuously provide a fresh supply of oil film to the bearings, pressurize the bearing housing against outside contaminants and cool the bearings slightly. A mist generator in which petroleum or synthetic lubricant is made into a fine aerosol mist of droplets, measuring 3-5 microns in size, is mixed with carrier air. The mixture is delivered by means of pipes, conduits, and tubings and is delivered automatically under low pressure to the bearing housing. Previously, a volume of air is continuously exhausted into the workplace area and the air contains oil mist, creating a back pressure in the bearing housing equal to the exit losses incurred. The disadvantage of known oil mist lubrication system is the constant escape of air/oil mist. This is often termed “stray mist” which permeates the entire area around and on the exterior surface of the misted equipment.
This stray mist or oil accumulation in the air has been taken care of in an environmental sense by proper ventilation and use of good mistable lubricants to reduce the amount of stray mist to a low level. However, there is always a significant amount of stray oil mist that escapes and is deposited on the surfaces in the workplace despite the best ventilation systems.
Government agencies, namely the Environmental Protection Agency (EPA), has tolerated the mist in the environment because it has not been proven to be harmful when ingested into the human body through inhalation, ingestion, or skin absorption. The most common way is inhalation and the National Institute of Occupation Safety and Health in the United States has established a threshold limit of oil mist in the air as 5 mg. per cubic meter. However, concentrations greater than 0.4 mg. per cubic meter result in a visible haze or cloud of mist, which accumulates on the equipment and surrounding structures, especially the floor, which renders this equipment slippery and unsafe in many ways. In any event, this oil must be cleaned-up and the oily residue disposed of in an environmentally safe manner which requires a great deal of time and money.
This constant loss of oil and the requirements of cleaning it up necessitated a method of providing the advantages of oil mist lubrication without the disadvantages, i.e., loss of oil through the stray mist emitted into the surrounding environment.
Applicant's invention will implement the retention and control of oil mist in a housing. This implementation would prevent any visible emission, such as fog, steam, mist, etc., or would be operable with a gas at a temperature below its critical temperature and/or for retention in the housing of the combination of a aerosol mist substance in air or other carriers. In many instances, such control is needed, such as to prevent steam from entering into a housing containing oil or a substance, such as oil in a second aerosol form.
Applicant's invention has been found to provide absolute control over oil mist or oil droplets escaping into the atmosphere along with the air carrier.
SUMMARY OF THE INVENTION
In order to prevent the escape of the lubricant from a bearing housing, this invention controls the mist and coalesces the mist aerosol into a liquid form. This liquid form may be drained into a bearing enclosure sump or other means of accumulating the oil and then removed to waste and/or recovery.
This invention provides for absolute control of the mist lubrication system or any other aerosol system, including a combination of a aerosol substance and a carrier, by retaining all of the oil or other aerosol substance contained in the mist within the bearing enclosure. The carrier or air, absent the aerosol substance, may escape the housing.
Any labyrinth seal, but preferably a seal which limits the axial movement between the rotor and stator of the seal may be utilized. The rotor may be driven by any normal drive means with the shaft about which the rotor is situated. The stator member is firmly sealed to the housing or vessel, which in the case of oil mist may enclose the bearing member. This invention provides a groove in the stator surrounding the shaft with a coalescing member inserted into this groove. The coalescing member is necessarily lubricous. A virgin Teflon® cord or ring placed into the collection groove in the stator within the housing works excellently. This collection or coalescing member is sized and positioned so as to be in intimate contact or “wear-in” contact with the rotating shaft. The coalescing member either wears or sublimates or abrades to within line-to-line or zero dimensional contact with the shaft. When the mist or vapor containing the oil or other vaporized substance impinges or encounters the coalescing member-to-shaft interface, the oil or other aerosol substance coalesces. This coalesced liquid may drip off or be deposited into drain grooves which drain and run to a sump. Because there is no frictional engagement between the coalescing member and the shaft, there is no wear to the coalescing surface after initial “run-in”. The life of the coalescing member is extended indefinitely due to this lack of wear.
The use of a coalescing member on a seal also controls loss of fluid when there is a non-pressurized oil lubricant provided in the housing for the bearings. The lubricant will normally be contained within the bearing housing and this seal will improve such containment. The coalescing member acts in the same manner to prevent the escape or travel of the oil along the shaft past the coalescing member.
The sides of the groove in the stator may be at right angles to the shaft. However, it has been found that to have one side, normally the side of the groove away from the exit of the shaft through the housing, at a slant from the perpendicular improves the coalescence and the flow return of the coalesced liquid or oil.
It has also been found that the addition of a second coalescing member or ring in a second groove located further away from the bearing along the shaft toward the exit of the shaft from the housing will improve the efficiency of coalescing of the oil mist and act as a further barrier to the escapement of oil along the shaft.
Further modifications of this invention include the addition of a third groove located further away from the bearing with a coalescing member or ring in the first and third grooves with the second groove being an open groove.
The above improvements are also operable with any aerosol vapor or combination of non-superheated vaporized substance with a carrier coalescing and retaining any substance in a vessel while the gaseous carrier may escape.
REFERENCES:
patent: 1562019 (1925-11-01), Wilkinson
patent: 4526388
Inpro Companies, Inc.
Knight Anthony
Peavey Enoch E.
Rockey Milnamow & Katz Ltd.
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