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:
Aug. 24, 2004
Filed:
Dec. 03, 2002
BOC Edwards Technologies Limited, Narashino, JP;
Abstract
A thread-groove pump mechanism portion PB employs a turn-back structure including a rotor formed of a multiple cylinder having an inner cylindrical rotor and an outer cylindrical rotor and a stator formed of a multiple cylinder having an inner cylindrical stator and on outer cylindrical stator. Gaps g and g defined by the outer walls of the rotor and the stator walls, and a gap g defined by the inner cylinder wall of the rotor and the stator wall during the rest of the pump are formed such that they increase with the distance from the rotor shaft center and g >g and g >g are satisfied. Thus, even if displacement occurs by the centrifugal force and thermal expansion during the operation of pump, predetermined gaps can be provided therebetween.