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:
Sep. 14, 2004
Filed:
Jul. 23, 2002
Howard Randall Wilhelm, Baltimore, MD (US);
Kaydon Corporation, Ann Arbor, MI (US);
Abstract
A dry gas seal has a housing with an annularly-shaped channel disposed concentric with the drive shaft, and an inlet to introduce pressurized buffer gas into the housing interior. An annularly-shaped shutdown piston is slidably received in the housing channel for axial shifting, and includes a circumferential seal between its inside and outside surfaces, and an end seal. A biasing member resiliently urges the shutdown piston toward an open position, such that during compressor operation, the forces generated by the biasing member combined with the pressure of the buffer gas acting on the piston's interior face retain the shutdown piston in the open position. During compressor shutdown, when the pressure of the buffer gas drops, the pressure of the process gas acting on the piston's exterior face overcomes the combined forces of the biasing member and the buffer gas to shift the shutdown piston to a closed position against an adjacent sealing surface to prevent contaminates from entering the housing interior.