Patent US4639199A successfully refreshed from Google Patents.
US4639199A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Two-shaft vacuum pump with internal compression
Assignee: Balzers und Leybold Deutschland Holding AG
•
Filing: 1986-01-30
•
Granted: 1987-01-27
•
Expires: 2006-01-30
Abstract
Abstract A two-shaft vacuum pump which draws gas in at an inlet and compresses it at a first outlet for discharge, thereby producing a vacuum at the inlet, has a second, pressure-responsive outlet from the area where the gas is compressed for discharge from the first outlet. The second outlet thereby relieves excess, compression gas pressure which could overload the pump motor, for example, at the start of operation when high-density gas is drawn in for compression.
Inventors
- 👤 Heinz Frings
- 👤 Hans-Peter Kabelitz
- 👤 Karl-Heinz Ronthaler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:37
CPC Classifications
F; F04; F04C; F04C28/00; F04C28/24; F04C18/00; F04C18/08; F04C18/12; F04C18/126
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
176 words
In a two-shaft vacuum pump having an enclosed, hollow casing, an inlet port into the hollow casing, two rotors on respective parallel shafts for rotation in the hollow casing, and an outlet port in a side of the casing normal to the shafts, each rotor having at least one protruberance and at least one indentation cooperative with the other on the other rotor and the hollow casing for cylically drawing gas in the inlet and compressing it at the outlet when the shafts correspondingly rotate the rotors, whereby the location of the outlet determines a characteristic of the vacuum-pumping operation of the vacuum pump, the improvement comprising: means for accommodating higher inlet pressures by relieving excessive compression pressures comprising a further outlet port (15) in a peripheral side of the casing parallel to the shafts and communicating with a place in the hollow casing at which the gas is compressed for the other outlet; and a pressure relief valve (16) responsive to the compressed pressure in the hollow casing and operative on the further outlet port.
Claim 2
Dependent Claim
176 words
In a two-shaft vacuum pump having an enclosed, hollow casing, an inlet port into the hollow casing, two rotors on respective parallel shafts for rotation in the hollow casing, and an outlet port in a side of the casing normal to the shafts, each rotor having at least one protruberance and at least one indentation cooperative with the other on the other rotor and the hollow casing for cylically drawing gas in the inlet and compressing it at the outlet when the shafts correspondingly rotate the rotors, whereby the location of the outlet determines a characteristic of the vacuum-pumping operation of the vacuum pump, the improvement comprising: means for accommodating higher inlet pressures by relieving excessive compression pressures comprising a further outlet port (15) in a peripheral side of the casing parallel to the shafts and communicating with a place in the hollow casing at which the gas is compressed for the other outlet; and a pressure relief valve (16) responsive to the compressed pressure in the hollow casing and operative on the further outlet port.
Claim 3
Dependent Claim
25 words
A vacuum pump according to claim 1, and further comprising a common exhaust pipe (46) connected to both of the two outlet ports (14, 15).
Claim 4
Dependent Claim
25 words
A vacuum pump according to claim 1, wherein the inlet port (13) is disposed in a peripheral side of the casing parallel to the shafts.
Claim 5
Dependent Claim
25 words
A vacuum pump according to claim 2, wherein the inlet port (13) is disposed in a peripheral side of the casing parallel to the shafts.
Claim 6
Dependent Claim
26 words
A vacuum pump according to claim 1, wherein the inlet port (13) is disposed in a side of the hollow casing generally transverse to the shafts.
Claim 7
Dependent Claim
26 words
A vacuum pump according to claim 2, wherein the inlet port (13) is disposed in a side of the hollow casing generally transverse to the shafts.
Claim 8
Dependent Claim
20 words
A vacuum pump according to claim 1, wherein the pressure relief valve (16) is at least one of weight-and spring-loaded.
Claim 9
Dependent Claim
20 words
A vacuum pump according to claim 3, wherein the pressure relief valve (16) is at least one of weight-and spring-loaded.
Claim 10
Dependent Claim
20 words
A vacuum pump according to claim 2, wherein the pressure relief valve (16) is at least one of weight-and spring-loaded.
Claim 11
Dependent Claim
20 words
A vacuum pump according to claim 5, wherein the pressure relief valve (16) is at least one of weight-and spring-loaded.
Claim 12
Dependent Claim
27 words
A vacuum pump according to claim 1, wherein the inlet port communicates with a Roots pump (23) for the first-claimed pump to be a backing pump therefor.
Claim 13
Dependent Claim
27 words
A vacuum pump according to claim 3, wherein the inlet port communicates with a Roots pump (23) for the first-claimed pump to be a backing pump therefor.
Claim 14
Dependent Claim
27 words
A vacuum pump according to claim 2, wherein the inlet port communicates with a Roots pump (23) for the first-claimed pump to be a backing pump therefor.
Claim 15
Dependent Claim
27 words
A vacuum pump according to claim 5, wherein the inlet port communicates with a Roots pump (23) for the first-claimed pump to be a backing pump therefor.
Claim 16
Dependent Claim
38 words
A pump combination according to claim 14, wherein the Roots pump has two rotors (24, 25) and the shafts (5, 6) of the first-claimed pump are operatively associated with the rotors (24, 25) of the Roots pump (23).
Claim 17
Dependent Claim
37 words
A pump combination according to claim 11, wherein the Roots pump has two rotors (24,25) and the shafts (5, 6) of the first-claimed pump are operatively associated with the rotors (24, 25) of the Roots pump (23).
Claim 18
Dependent Claim
38 words
A pump combination according to claim 12, wherein the Roots pump has two rotors (24, 25) and the shafts (5, 6) of the first-claimed pump are operatively associated with the rotors (24, 25) of the Roots pump (23).
Claim 19
Dependent Claim
38 words
A pump combination according to claim 13, wherein the Roots pump has two rotors (24, 25) and the shafts (5, 6) of the first-claimed pump are operatively associated with the rotors (24, 25) of the Roots pump (23).
References Cited (Backward Citations)
US1818767A
Cited
US2129960A
Cited
GB625490A
Cited
GB633818A
Cited
US3677664A
Cited
US3844695A
Cited
US3989413A
Cited
US4068988A
Cited
EP0009916A1
Cited
SU794258A1
Cited
GB2088957A
Cited
DE3147824A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-01-26 | 1990-07-28 | 1991-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-26 | 1994-07-28 | 1995-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-26 | 1998-07-28 | 1999-01-27 | $7700.00 | Window Closed / Lapsed |