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. 18, 2004
Filed:
May. 22, 2002
Zhixin Li, Hudson, NH (US);
Ferrotec (USA) Corporation, Nashua, NH (US);
Abstract
In a ferrofluid seal that supports a pressure differential between a low pressure side and a high pressure side, a reservoir is created between a first seal stage at the low pressure side and its adjacent seal stage. The volume of the reservoir is relatively large compared to the volumes of the interstage areas between the other seal stages. In addition, a controlled leakage path bypasses the first stage from the reservoir to the low-pressure area. The leakage rate through the bypass path is controlled so that gas in the reservoir leaks to the low-pressure area relatively slowly, for example, the bypass path might equalize the pressure across the first stage over a five-minute interval. This arrangement prevents a seal stage burst from disgorging a large gas volume into the low-pressure side.