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:
Jan. 14, 1997
Filed:
Nov. 22, 1995
William B Mraz, Epping, NH (US);
Thomas J Black, Jr, Merrimack, NH (US);
Paul E McMahan, Walker, LA (US);
Larry A Hufford, Valley Center, CA (US);
David T Mooney, San Rafael, CA (US);
Robert C Watkins, Moss Point, MS (US);
Ferrofluidics Corporation, Nashua, NH (US);
Abstract
A ferrofluidic seal is fitted with a centering ring having an inner edge adapted for engagement with a rotating shaft for centering the seal about the rotating shaft. The centering ring automatically engages the shaft and centers the seal when the seal is fitted onto the shaft. The centering ring is affixed to the housing, and/or magnet and pole module. In one embodiment, the centering ring may be removed after it performs its centering function. In another embodiment, the centering ring is non-removable and remains within the seal permanently. According to this latter embodiment, the centering ring serves the additional purpose of retaining ferrofluid, expelled from the seal during 'bursting', within magnetic reach of the seal so as to be re-drawn into the seal, thus extending seal life. Additionally, a ferrofluid retaining ring absent a centering function may be employed. The centering ring provides for easy installation and accurate centering of a seal with which it is used, and yields a highly functional and operationally safe seal.