The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 01, 1984
Filed:
Feb. 22, 1983
Ferrofluidics Corporation, Nashua, NH (US);
Abstract
A single-stage, ferrofluid magnetic seal apparatus and method which comprises: an annular, permanent-magnet ring element adapted to surround a shaft to be sealed, which shaft extends between first low-pressure and second high-pressure; first and second pole pieces in a magnetic-flux relationship with the permanent magnet, and having one and the other ends, the other end extending into a close, noncontacting relationship with the surface of the shaft, to define a radial gap therebetween; a plurality of stages formed in the radial gap under the other end of the second pole piece, which pole piece is placed toward the high-pressure side the environment, and the radial gap under the first pole piece, placed toward the low-pressure side of the environment, being shallow and generally less than about 2 mils; and ferrofluid in the radial gap under the other end of the second pole piece which forms a plurality of separate O-ring ferrofluid seals of defined pressure capacity, thereby providing a single-stage, ferrofluid magnetic seal apparatus and method, which seal apparatus has a reduced tendency to permit unpredictable air bursts, when installed about the rotary shaft between first and second pressure environments.