John Crane Inc.

Robert Peter Rieger

James R Wasser

Glenn G Pecht

Ralph P Gabriel

Anca Vasilache

John P Czubek

A contacting mechanical end face seal for use in applications having slow shaft rotational speeds, such as mixers, agitators and reactors, includes at least one seal ring having a face with spiral grooves. Both hydrostatic and hydrodynamic lift characteristics in the seal are utilized to generate and maintain a seal gap having sufficient stiffness to prevent contact of the seal ring faces during operation. Specific characteristics, or combinations of them, include a land to groove ratio between 0.2-0.9, tapered groove surfaces which are inclined from the O.D. toward the dam, groove area to land area ratios greater than 1.5, a stepped groove having a greater depth at the O.D. relative to the depth adjacent the dam, alternating deep and shallow grooves, and groove area to dam area ratio in the interface greater than 1.2. Disposing the grooves in the axially movable primary ring and providing a greater sealing area for the opposing mating ring seal face limits angular load imbalance in the seal by maintaining the grooved area within the seal interface. The seal may be utilizable in both single or dual seal arrangements.

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Lombard, IL, United States of America

Robert Peter Rieger