Title:
SCREW VACUUM PUMP
Document Type and Number:
Japanese Patent JPH0518382
Kind Code:
A
Abstract:
PURPOSE: To provide a screw vacuum pump which is compact and high in ultimate vacuum.
CONSTITUTION: This screw pump is provided with a pair of male rotor 7 and female rotor 7A rotated with engaged with each other around two parallel shafts and a casing 1 for storing both the rotors, the casing 1 is provided with a suction port 8b and a discharge port 9b, and it is constituted by an intake process for sucking a gas into a rotor from the intake port 8b, a transfer process for transfer, a compression process for compression and a discharge process for discharge from the discharge port 9b. And by closing the suction port earlier, an expansion process is provided between the suction process and the transfer process.
Inventors:
SHIMIZU NOBU
YANAGISAWA SEIJI
YANAGISAWA SEIJI
Application Number:
JP19594591A
Publication Date:
January 26, 1993
Filing Date:
July 10, 1991
Export Citation:
Assignee:
EBARA CORP
International Classes:
F04C18/16; F04C23/00; F04C25/02; F04C29/12; (IPC1-7): F04C23/00; F04C25/02
Domestic Patent References:
| JPS52112809A | 1977-09-21 | |||
| JPS62284994A | 1987-12-10 | |||
| JPS62243982A | 1987-10-24 |
Attorney, Agent or Firm:
Takashi Kumagai (1 outside)