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:
Oct. 10, 1995
Filed:
May. 16, 1994
John C Helmer, Menlo Park, CA (US);
Giampaolo Levi, Turin, IT;
Varian Associates, Inc., Palo Alto, CA (US);
Abstract
The present invention refers to a pumping stage particularly designed for turbomolecular pumps, having increased compression ratio, and capable of extending the operating range of the turbomolecular pump towards high pressure. The new pumping stage comprises a casing housing, a rotor disk, and a substantially coplanar stator ring. The stator ring consists of two plates connected with each other along their circumferential periphery, thereby defining a region of close tolerance with the opposite surfaces of the rotor. The rotor and stator cooperate to define a tapered, free annular channel having a suction port and a discharge port at the opposite ends of this channel. The channel tapers in a functional, predetermined fashion, having the largest cross-sectional area near the suction port, and converging, according to the rotational direction of the rotor, at the discharge port.