Split mechanical face seal

Details Split mechanical face seal Split mechanical face seal

2000-09-06

2002-11-26

Mah, Chuck Y. (Department: 3626)

Seal for a joint or juncture

Seal between relatively movable parts

Relatively rotatable radially extending sealing face member

C277S374000, C277S377000

Reexamination Certificate

active

06485024

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to mechanical seals for pumps and other machinery having rotating shafts and, more particularly, to a split mechanical face seal.
2. Description of the Prior Art
Mechanical seals are used in a wide variety of machines, e.g., pumps, having rotating shafts that pass through housings in order to prevent leakage of pressurized fluids. In one type of mechanical seal, the rotary face seal, sealing is achieved by arranging at least two rigid, durable sealing rings having flat, radially extending sealing surfaces axially adjacent each other and concentrically about the shaft so that the faces are in sealing contact. One seal ring is held stationary in the seal housing or gland while the other rotates with the shaft.
Repair or replacement of parts of such seals is difficult whenever inaccessibility of the outboard end of the shaft or the location of this machine makes it impossible to take the seal off the end of the shaft. In such situations, the machines themselves must be disassembled.
One solution to this problem has been to split the sealing rings and other seal parts radially into two or more segments so that each ring may be removed from the seal and new rings reassembled within the seal and about the shaft as disclosed, for example, in U.S. Pat. Nos. 4,576,384 and 5,961,122, both of which are incorporated herein by reference for all purposes.
Split mechanical face seals of the prior art typically have numerous parts. For example, it is common in split face seals to bias the stationary face seal against the rotating face seal by means of a plurality of springs carried in the gland or housing of the mechanical seal. In assembling split seals employing multiple springs for biasing purposes, it is not uncommon for the springs to fall out of the gland or other spring retainer during assembly, making the assembly job tedious and time-consuming. Furthermore, it is difficult to hold various parts of the split seal assembly in concentric relationship with the shaft on which they are mounted during assembly.
SUMMARY OF THE INVENTION
It is therefore an object ofthe present invention to provide a split mechanical face seal that is easy to assemble and disassemble.
Another objects of the present invention is to provide a split mechanical face seal wherein the biasing members are carried on a single piece spring retainer.
Yet another object of the present invention is to provide a split mechanical face seal having a removable alignment sleeve for ease of assembly.
The above and other objects of the present invention will become apparent from the drawings, the description given herein and the appended claims.
In one embodiment, the split mechanical face seal of the present invention includes a rotating seal ring assembly having a rigid seal ring of split ring segments forming rotating seal ring faces and a pair of attachable body ring segments holding the rotating seal rings segments together when the body ring segments are attached. There is also a stationary seal ring assembly comprising a rigid seal ring of split ring segments forming stationary seal ring faces and a pair of attachable housing segments holding the stationary seal ring segments together when the housing segments are attached. A single segment retainer ring has a split forming first and second opposing end faces. The retainer ring is made of a material that has sufficient flexibility such that the first and second end faces can be spread apart by a distance at least equal to the diameter of the circle formed when the first and second faces are in engagement. The retainer ring has first and second axially facing surfaces, the retainer ring being operatively engaged with the stationary seal ring segments to apply a biasing force thereto by means of resilient members carried by the retainer ring and that engage axially facing abutments formed by the housing segments when the housing segments are attached.
In another embodiment of the present invention, there is provided a split mechanical face seal with a positioning collar or sleeve that holds the stationary seal ring assembly in a generally concentric relationship with respect to a shaft upon which the face seal is mounted, the positioning collar being removable when assembly of the split mechanical face seal is completed.


REFERENCES:
patent: 4502694 (1985-03-01), Uhrner
patent: 4576384 (1986-03-01), Azibert
patent: 5020809 (1991-06-01), Mullaney
patent: 5058904 (1991-10-01), Nevola
patent: 5354070 (1994-10-01), Carmody
patent: 5370401 (1994-12-01), Sandgren
patent: 5961122 (1999-10-01), Marsi
patent: WO89/02999 (1989-04-01), None
Flier: “Chesterton 221 Split Seal,” 6 pages. A. W. Chesterton Co., Stoneham, Massachusetts, 1990.
Flier: “Chesterton 442 Split Mechanical Seal,” 4 pages. A. W. Chesterton Co., Stoneham, Massachusetts, 1994.
Flier: “The PSS Dura Seal,” 4 pages. Durametallic Corporation, Kalamazoo, Michigan, 1990.
Flier: “Style 85 Split Cartridge Seal,” 5 pages. Flex-A-Seal, Inc., Essex Junction, Vermont. Admitted prior art.
Flier: “Power Packing's New 1200S Split Seal,” 2 pages. Power Packing Company, Inc., Baton Rouge, Louisiana. Admitted prior art.
Flier: “PPC's 2400S Split Double Seal,” 4 pages. Power Packing Company, Inc., Baton Rouge, Louisiana. Admitted prior art.
Flier: “John Crane Type 3710 Cartridge Split Seal,” 2 pages. John Crane Sealol, Cranston, Rhode Island, 1998.
Flier: “PPC's 1200S Split Seal,” 4 pages. PPC Mechanical Seals, Baton Rouge, Louisiana. Admitted prior art.

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