US Patent: 4,299,398
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| Pressure Compensating Shaft Seal
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Patentee:
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| Edward C. Wahl (exact or similar names) - Arlington Heights, Cook County, IL |
| Manufacturer: |
| Not known to have been produced |
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Patent Dates:
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| Applied: |
Nov. 13, 1979 |
| Granted: |
Nov. 10, 1981 |
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Joel Havens
"Vintage Machinery" entry for Gits Bros. Mfg. Co.
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Description: |
| Abstract:
Relatively rotating face ring-type shaft seals especially useful for sealing the shaft bearings and lubricant chamber of mud motor driven downhole drill rigs, have a plurality of telescoped annular seal rings slidably mounted in an annular carrier element and riding over the radial face on a face ring to define a sealed intermediate chamber therebetween. This intermediate chamber may be filled with lubricant. Either the telescoped rings or the face rings rotate with the shaft. Biasing means, such as a plurality of springs, load end faces on the seal rings against the radial face of the face ring. Pressure transmission means, such as pistons, O-rings, or the like, mounted in either the carrier element or the face ring, are loaded by the ambient media pressure, such as drilling fluid, to maintain pressure in the intermediate chamber responsive to the pressure of the ambient media. When the areas of the pressure transmission means exposed to ambient pressure and to intermediate chamber pressure are equal, a zero or negligible pressure differential will be maintained across the outer telescoped seal ring to prevent the ambient media, which is frequently quite abrasive, from entering the outer sealing ring interface. The inner telescoped seal ring serves as an auxiliary back-up face ring seal for the protected bearing chamber. Since the abrasive media being sealed does not enter the interfaces of the rings, the end faces of the inner and outer sealing rings riding on the face ring can be reduced or narrowed to a minimum and coated with a hard facing material such as tungsten carbide. |
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