Seal for a joint or juncture – Seal between relatively movable parts – Relatively rotatable radially extending sealing face member
Reexamination Certificate
1999-05-04
2001-12-04
Browne, Lynne H. (Department: 3629)
Seal for a joint or juncture
Seal between relatively movable parts
Relatively rotatable radially extending sealing face member
C277S372000, C277S374000
Reexamination Certificate
active
06325381
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates o the fluid sealing arts. More particularly, the present invention relates to a high-pressure rotary face seal for inhibiting fluid flow between a housing and a shaft which rotate relative to each other.
Mechanical face seals for use in rotary applications are well known. These seals are used in pumps, compressors, agitators, mixers, and a wide variety of other apparatus including a housing in which a shaft is supported for rotation. The face seals inhibit fluid flow between the housing and shaft.
While prior face seals have been found to be generally effective, they have not been found to be sufficiently long-lasting. This has necessitated their frequent replacement which results in down-time for the relevant apparatus. Even when these prior seals have been split to facilitate their removal from and installation on an associated shaft, at least, machine down-time is still significant.
Prior seals have been found to be relatively high-cost, unduly complex (e.g., multiple slits), and have also required relatively large amounts of space for installation. The complexity and space requirements have prevented such prior seals from being used in “closed” applications, i.e., applications where the seal must be installed inside of a fixed housing or the like where no access to the ultimate seal location is permitted. Thus, for example, these prior seals would not be usable in a “closed-groove” applications where a seal member must be installed in a grove circumscribing a shaft or the like, and wherein the shaft must then be axially inserted into a closed housing. Furthermore, in such closed-groove applications, multiple sealing points are often required (due to the presence of multiple fluid ports for communicating fluid from outside of the housing into passages extending through the shaft), and prior seals are not practical in such cases due to space, complexity, and cost considerations.
Another deficiency associated with known face seals is their diminished effectiveness at low fluid pressures. This results when low-pressure fluid is able to “seep” past the seal without engaging the seal and urging it into its operative sealing condition. Thus, for example, with prior seals, fluid is able to move past the seal for at least an initial period of time until sufficient fluid pressure is exerted on the seal to urge it into sealing engagement with the shaft or other component.
In light of the foregoing deficiencies and others associated with prior mechanical rotary face seals, it has been deemed desirable to develop a new and improved rotary face seal which overcomes these deficiencies and others while providing better and more advantageous overall results.
SUMMARY OF THE INVENTION
In accordance with the present invention, a new and improved rotary face seal is provided.
In accordance with a first aspect of the present invention, a rotary seal is adapted for placement on an associated rotating shaft to inhibit fluid flow between the shaft and an associated housing. The seal includes an annular main seal member having a peripheral surface, an inner surface defining a central opening, and first and second transverse faces. One of the transverse faces defines a sealing face adapted for sealingly abutting a transverse surface of the associated shaft in a substantially fluid-tight manner. A resilient annular sealing member circumscribes the main seal member and projects radially outwardly therefrom. The resilient annular sealing member is, thus, adapted to sealingly engage the associated housing and the main seal member to inhibit fluid flow therebetween. The resilient sealing member also rotatably fixes the main seal member to the associated housing. An inner ring member is slidably received in a groove defined in the inner surface of the main seal member. The inner ring member is closely received on the associated shaft and is adapted to exert axial force on the main seal member in a first direction in response to fluid pressure exerted on the inner ring member in the first direction.
In accordance with another aspect of the present invention, a seal assembly includes an inner ring member adapted for co-axial placement on an associated shaft in the region of a transverse shaft face and at least substantially circumscribes the associated shaft. A main annular seal member is adapted for co-axial placement on the associated shaft in a manner circumscribing the shaft and in covering relation with the inner ring. The main seal member includes an annular sealing face adapted for sealingly engaging the transverse shaft face to inhibit fluid flow between said main seal member and the transverse shaft face. An annular outer seal member is received on a peripheral surface of said main seal member and projects radially outwardly therefrom. The outer seal member is arranged co-axially with the associated shaft and is adapted to inhibit fluid flow between the peripheral surface of the main seal member and a housing surrounding the associated shaft.
In accordance with a further aspect of the present invention, an apparatus includes a housing defining a cylindrical bore and a shaft co-axially supported in the bore for rotation relative to the housing. The shaft includes a transverse face. A seal assembly is positioned co-axially on the shaft and radially between the shaft and housing for inhibiting fluid flow between the shaft and housing. The seal assembly, itself, includes a main seal member defined by at least an inner surface, an outer surface, and first and second side surfaces arranged transverse to the inner and outer surfaces. The second transverse surface is placed adjacent the transverse shaft surface and defines a sealing surface for substantially preventing fluid flow between the sealing surface and the transverse shaft face. An outer annular seal member is received on the outer surface of the main seal member co-axial with the shaft and sealingly engaged with the housing and main seal member to inhibit fluid flow therebetween. An inner ring is received in a groove formed in the inner surface of the main seal member and is circumferentially slidable relative to the main seal member.
In accordance with another aspect of the invention, a seal assembly includes a split annular main seal member including cylindrical inner and outer surface arranged co-axially, and a transverse sealing face having a seal area and a pressure relief area. The seal assembly further includes a split inner ring member at least partially recessed into the cylindrical inner surface and arranged co-axially with the inner surface. An O-ring seal is partially recessed into the outer cylindrical surface and arranged co-axially with the outer surface.
One advantage of the present invention is the provision of a new and improved high-pressure rotary seal.
Another advantage of the present invention resides in the provision of a high-pressure rotary seal that is effective and long-lasting without being unduly complex and expensive.
A further advantage of the present invention is found in the provision of a high-pressure rotary seal that also provides effective sealing at low fluid pressures.
Still another advantage of the present invention is the provision of a high-pressure rotary seal that is easy to install and replace, especially in closed-groove applications.
Yet another advantage of the present invention resides in the provision of a high-pressure rotary seal with an inner, labyrinth ring that exerts axial force on a main seal ring to urge the main seal ring into its operative, sealing condition.
A further advantage of the present invention is the provision of a high-pressure rotary seal which defines a relief chamber for preventing the exertion of excessive axial force on the main seal member as would result in damage to the seal from excessive friction.
Still other benefits and advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the present specification.
REFERENCES:
patent: 1849359 (1932-0
Bochna David E.
Browne Lynne H.
Fay Sharpe Fagan Minnich & McKee LLP
System Seals, Inc.
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