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Dynamic Seal

IP.com Disclosure Number: IPCOM000079837D
Original Publication Date: 1973-Sep-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Leong, GH: AUTHOR [+3]

Abstract

A perfect seal must be maintained, at all times, on a hydrostatic spindle. Zero leakage, zero friction, and small size are some of the necessary characteristics.

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Dynamic Seal

A perfect seal must be maintained, at all times, on a hydrostatic spindle. Zero leakage, zero friction, and small size are some of the necessary characteristics.

Described is a precision machined part with its internal diameter matched to the diameter of the shaft to be sealed. The seal has appropriately dimensioned grooves and internal passageways. It can be built for single stage or multistage sealing.

Fig. 1 shows a single-stage seal. In operation, compressed air is supplied to the inlet ports A1 and A2. The air passes through the internal passageways to the outlet ports B1 and C1, and finally distributed through the circular slot S1 to uniformly flood the volume provided by the clearance between the seal and the shaft.

As indicated in Fig. 1, the seal has an escapement side and a sealing side. The sealing side is the active portion of the seal. By pressure equalization and capillary restriction, the static air pressure balances against the fluid pressure to establish an equilibrium boundary within the sealing side, thus effectively preventing fluid leakage beyond the seal. The escapement side provides additional pressure balancing and also allows excess air to exit to the exterior.

The operation of the multistage seal is similar to that of the single-stage seal. Illustrated in Fig. 2 is an n-stage seal. For the multistage configuration, air escapement ports E1, E2 and circular slots D1, D2 are added to provide an exit path for air in the intermed...