Seal for a joint or juncture – Seal between relatively movable parts – Close proximity seal
Reexamination Certificate
1998-03-26
2001-01-09
Knight, Anthony (Department: 3626)
Seal for a joint or juncture
Seal between relatively movable parts
Close proximity seal
Reexamination Certificate
active
06170832
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to the field of sealing a fluid medium. More particularly, the invention concerns fluid ring seals and a system that employs multiple fluid ring seals to seal the fluid medium in a fluid medium chamber and seal contaminants out of the fluid medium chamber, which chamber preferably encircles a shaft mounted for rotation.
BACKGROUND OF THE INVENTION
Various sealing means exist in the prior art for sealing a fluid medium in a fluid medium chamber. In particular, as depicted in FIGS.
1
a
,
1
b
and
2
, static seals are conventionally used. For example, FIGS.
1
a
and
1
b
depict a conventional rail car axle bearing assembly. The assembly includes a bearing assembly housing B. Within the housing B a spacer C is positioned interiorly midway between the housing ends. A bearing cone D, comprising a pair of such cones sit inside the housing pressed against either side of the spacer. A series of bearings D′ are mounted within the bearing ring. A seal ring E sits against the bearing cone D, where again a pair of such rings sit inside the housing pressed against either side of the respective bearing cones D.
Within the ring seal E is a static seal F. The static seal engages an outer surface of a wear ring G in a rotatable frictional relationship. The wear ring G sits against the bearing cone D, where again a pair of such rings pressing engage against either side of the respective bearing cones D. The wear ring is engaged by either an end plate H with connecting means such as a bolt I (bearing outside mounting arrangement) or a backing plate J that removably engages a shoulder of an axle or shaft K. The end plate and connecting means enable pre-loading of the bearing assembly as desired.
In rotational operation, for example, the components D, C, G, H, I, J and K rotate and the components B, E and F are fixed or stationary relative thereto. The static seal F rotatably seals by engaging an outer surface of the wear ring G in a rotatable frictional relationship. A fluid medium chamber L is formed between the ring seal E and the bearing cone D. A fluid medium such as oil or grease is located within the chamber L. By the frictional relationship created between the static seal and the wear ring, the seal F serves to prevent the fluid medium from escaping out of the chamber, and also, prevent contaminants (e.g., substances in an outer environment other the fluid medium such as air, water dirt and debris) from migrating into the chamber L.
FIG. 2
depicts another example of a bearing assembly that employs a static type seal in a conventional steel rolling mill shaft application. The components of this system are generally analogous to the components of the rail car axle system in function. Obviously the geometry of the components differ but they operate largely the same way.
These and other types of bearing assembly arrangements known in the prior art have several disadvantages. Arrangements that employ static seals have a tendency to wear out relatively quickly. Once the static seal looses its ability to consistently maintain frictional contact with the rotating wear ring, leakage into and out of the fluid medium chamber is inevitable. Further, such arrangements attempt to accomplish the two tasks of sealing in the fluid medium and sealing out contaminants with one component. Still further, such arrangements rely on the frictional relationship which has obvious disadvantages to inhibiting free rotation of the rotating system.
Still other arrangements that do not necessarily employ static seals suffer from similar disadvantages. For example, such arrangements do not consider fluid medium flow characteristics or utilize distinct yet cooperating components to circulate the fluid medium into moving walls for fluid containment and/or contaminant prevention and/or temperature regulation. Further, such arrangements do not actively circulate a fluid medium and utilize pressure differentials created by the arrangement to contain the fluid medium and prevent the migration of contaminants. Still further, other disadvantages that exist in the prior art arrangements will become clear after considering the features and advantages of the present invention.
A fluid ring sealing system is needed that overcomes the disadvantages of the prior art sealing arrangements. Accordingly, the present invention includes features that overcome these and other disadvantages. The seals and seal systems disclosed in the prior art do not offer the flexibility and inventive features of my system and method. As will be described in greater detail hereinafter, the features of the present invention differ from those previously proposed.
SUMMARY OF THE INVENTION
According to the present invention there is provided a fluid ring seal system and method for use with a shaft encircled by a fluid medium chamber including a fluid medium. The system includes a fluid medium sealing segment in fluid flow communication with the fluid medium chamber, wherein the fluid medium sealing segment is downstream of the fluid medium chamber and substantially maintains the fluid medium within the fluid medium chamber and the fluid medium sealing segment. The system also includes a contaminant sealing segment in fluid flow communication with the fluid medium sealing segment and with an outer environment, wherein the contaminant sealing segment substantially prevents a contaminant from migrating into the fluid medium sealing segment. Further, the system may include the contaminant sealing segment axially disposed downstream of the fluid medium sealing segment and a fluid pathway extending between the fluid medium sealing segment and the contaminant sealing segment along an innermost radius defined by each respective sealing segment, wherein the sealing segments are preferably in fluid flow communication with each other substantially only through the fluid pathway.
Another feature of the invention relates to the system including, additionally or alternatively, the contaminant sealing segment located downstream of the fluid medium sealing segment and a stator at least partially separating the fluid medium sealing segment and the contaminant sealing segment, the stator having a stator arm extending into a rotor cavity of each of the respective sealing segments.
Still another feature of the invention concerns the axial and/or radial positioning of the sealing segments relative to one another and/or the bearing assembly.
According to other features of the invention there is provided a charger ring located upstream of the fluid medium sealing segment and in the fluid medium chamber, wherein the charger ring automatically maintains a ring of fluid medium in proximity to a radial charger channel defined between the fluid medium sealing segment and the charger ring.
Yet another feature of the invention relates to a fluid medium circulation path, wherein the fluid medium circulation path flows in communication with the fluid medium chamber and the fluid medium sealing segment.
According to still further features of the invention there is provided a method for sealing a fluid medium in and contaminants out of a fluid ring seal system including a fluid medium chamber. Preferably the method comprises the steps of: rotating a fluid medium sealing segment; rotating a contaminant sealing segment; circulating a flow of the fluid medium between the fluid medium sealing segment and the fluid medium chamber and along a stator located between the fluid medium sealing segment and the contaminant sealing segment; circulating a flow of a contaminant between the contaminant sealing segment and the outer environment and along the stator; and, reducing a temperature of the fluid medium as it is circulating between the fluid medium sealing segment and the fluid medium chamber by circulating the flow of fluid medium along a temperature regulated stator.
REFERENCES:
patent: 3765688 (1973-10-01), Junker
patent: 3853327 (1974-12-01), Nellis
patent: 4383720 (1983-05-01), Ernst
patent: 4386780 (1983-06-01), Dernedde
patent
Heslin & Rothenberg, P.C.
Knight Anthony
Schwing Karlena D.
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