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Title:
SCREW VACUUM PUMP
Document Type and Number:
Japanese Patent JPH0518380
Kind Code:
A
Abstract:

PURPOSE: To provide a screw vacuum pump which can reduce a load of the screw vacuum pump at starting or evacuation.

CONSTITUTION: This screw vacuum pump is provided with a pair of male rotor 7 and female rotor 7A rotated with engaged to each other around two parallel shafts and a casing 1 for storing both the rotors 7 and 7A, and the casing 1 is provided with a suction port 8b and a discharge port 9b. When a space capacity formed by the casing 1 and the male and female rotors immediately after a gas is enclosed is, defined as V1 and the space capacity immediately before discharge is V2, the discharge port 9b is formed so that V1/V2 is within the range of 1.5 to 0.51.


Inventors:
SHIMIZU NOBU
YANAGISAWA SEIJI
Application Number:
JP1991000195943
Publication Date:
January 26, 1993
Filing Date:
July 10, 1991
Export Citation:
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Assignee:
EBARA CORP
International Classes:
F04C25/02; F04C18/16; F04C23/00; F04C29/12; (IPC1-7): F04C25/02
Domestic Patent References:
JPH0278783A1990-03-19
JPS62284994A1987-12-10
JPS62243982A1987-10-24
Attorney, Agent or Firm:
熊谷 隆 (外1名)



 
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