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:
Nov. 24, 1987
Filed:
Aug. 14, 1986
Applicant:
Inventors:
Assignees:
Rikagaku Kenkyusho, Wako, JP;
Osaka Vacuum, Ltd., Osaka, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F04D / ;
U.S. Cl.
CPC ...
415 72 ;
Abstract
A hollow cylindrical stator and a cylindrical rotor are disposed in the stator with a gap therebetween, the inner peripheral surface of the stator or the outer peripheral surface of the rotor being provided with a helical groove, or thread groove, and evacuation being performed by rotation of the rotor. The width of the helical groove adjacent the suction side of the pump is larger than the width of a ridge between adjacent turns of the groove.