US4668160A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vacuum pump
Assignee: Hitachi Ltd
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Filing: 1986-04-24
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Granted: 1987-05-26
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Expires: 2006-04-24
Abstract
Abstract A vacuum pump including a centrifugal compressor stage on the side of a suction opening and a circumferential flow compressor on the side of an exhaust opening. The centrifugal compressor pump works as a Siegbahn pump at a steady state, and works as a centrifugal compressor under a transient condition at the initial stage of the pump operation, thus obtaining a high pumping speed under the transient condition.
Inventors
- 👤 Masahiro Mase
- 👤 Takashi Nagaoka
- 👤 Yoshitsugu Tsutsumi
- 👤 Minoru Taniyama
- 👤 Makoto Terajima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:12
CPC Classifications
F; F04; F04D; F04D19/00; F04D19/02; F04D17/00; F04D17/08; F04D17/16; F04D17/168; F04D23/00; F04D23/008
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
154 words
A vacuum pump comprising: a housing including suction and exhaust openings, a rotating shaft rotatably supported in said housing, a plurality of fixed members attached to an inner wall of said housing, and a plurality of rotating members attached to said rotating shaft, said fixed members and said rotating members being disposed alternately so as to form pump stages in which a centrifugal compressor stage is formed on a side of said suction opening and a circumferential flow pump stage is formed on a side of said exhaust opening, said rotating member of said centrifugal compressor stage including open-form impellers having a plurality of backward vanes, and wherein said fixed member of said centrifugal compressor stage includes a fixed disc plate with a plurality of vanes disposed so as to face a reverse side of said impeller and inwardly directed relative to the direction of rotation at an outside diametral portionof said fixed member.
Claim 2
Dependent Claim
154 words
A vacuum pump comprising: a housing including suction and exhaust openings, a rotating shaft rotatably supported in said housing, a plurality of fixed members attached to an inner wall of said housing, and a plurality of rotating members attached to said rotating shaft, said fixed members and said rotating members being disposed alternately so as to form pump stages in which a centrifugal compressor stage is formed on a side of said suction opening and a circumferential flow pump stage is formed on a side of said exhaust opening, said rotating member of said centrifugal compressor stage including open-form impellers having a plurality of backward vanes, and wherein said fixed member of said centrifugal compressor stage includes a fixed disc plate with a plurality of vanes disposed so as to face a reverse side of said impeller and inwardly directed relative to the direction of rotation at an outside diametral portionof said fixed member.
Claim 3
Dependent Claim
136 words
A vacuum pump comprising: a housing including suction and exhaust openings, a rotating shaft rotatably supported in said housing, a plurality of fixed member attached to an inner wall of said housing, and a plurality of rotating members attached to said rotating shaft, said fixed members and said rotating members being disposed alternately so as to form pump stages in which a centrifugal compressor stage is formed on a side of said suction opening and a circumferential flow pump stage is formed on a side of said exhaust opening, said rotating member of said centrifugal compressor stage including open-form impellers having a plurality of backward vanes, and wherein a diameter of said circumferential flow compressor stage on a side of said exhaust opening is smaller than a diameter thereof on a side of said suction opening.
Claim 4
Dependent Claim
136 words
A vacuum pump comprising: a housing including suction and exhaust openings, a rotating shaft rotatably supported in said housing, a plurality of fixed member attached to an inner wall of said housing, and a plurality of rotating members attached to said rotating shaft, said fixed members and said rotating members being disposed alternately so as to form pump stages in which a centrifugal compressor stage is formed on a side of said suction opening and a circumferential flow pump stage is formed on a side of said exhaust opening, said rotating member of said centrifugal compressor stage including open-form impellers having a plurality of backward vanes, and wherein a diameter of said circumferential flow compressor stage on a side of said exhaust opening is smaller than a diameter thereof on a side of said suction opening.
Claim 5
Dependent Claim
140 words
A vacuum pump according to claim 2, comprising: a housing including suction and exhaust openings, a rotating shaft rotatably supported in said housing, a plurality of fixed member attached to an inner wall of said housing, and a plurality of rotating members attached to said rotating /shaft, said fixed members and said rotating members being disposed alternately so as to form pump stages in which a centrifugal compressor stage is formed on a side of said suction opening and a circumferential flow pump stage is formed on a side of said exhaust opening, said rotating member of said centrifugal compressor stage including open-form impellers having a plurality of backward vanes, and wherein a diameter of said circumferential flow compressor stage on a side of said exhaust opening is smaller than a diameter thereof on a side of said suction opening.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-05-25 | 1990-11-24 | 1991-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-25 | 1994-11-24 | 1995-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-25 | 1998-11-24 | 1999-05-26 | $7700.00 | Window Closed / Lapsed |