US3756753A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Two stage screw rotor machines
Assignee: Svenska Rotor Maskiner AB
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Filing: 1971-07-13
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Granted: 1973-09-04
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Expires: 1991-07-13
Abstract
Abstract A two-stage screw rotor compressor in which each stage is provided with an adjustable slide valve for varying the volumetric capacity of the stage which makes it possible to vary the capacity of the compressor within wide limits while maintaining a higher efficiency within the whole operating range than in hitherto known compressors of this type. Preferably the two valves are interconnected to move in unison.
Inventors
- 👤 W Persson
- 👤 L Benedictus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:33
CPC Classifications
F; F01; F01C; F01C20/00; F01C20/10; F01C20/12; F01C20/125; F04; F04C; F04C18/00; F04C18/08; F04C18/12; F04C18/14; F04C18/16
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
52 words
In a two-stage screw rotor machine for an elastic working fluid in which each stage includes a pair of intermeshing screw rotors, the improvement wherein each stage comprises adjustable valve means for varying the volumetric capacity of the respective stage and means for concurrently operating said adjustable valve means of each stage.
Claim 2
Dependent Claim
52 words
In a two-stage screw rotor machine for an elastic working fluid in which each stage includes a pair of intermeshing screw rotors, the improvement wherein each stage comprises adjustable valve means for varying the volumetric capacity of the respective stage and means for concurrently operating said adjustable valve means of each stage.
Claim 3
Dependent Claim
24 words
A machine as defined in claim 1, in which the adjustable valve means include movable valve members which are interconnected to move in unison.
Claim 4
Dependent Claim
58 words
A machine as defined in claim 1, in which the adjustable valve means each include an axially slidable valve member which is biassed towards its full capacity position by the fluid pressure at the high pressure end of the respective stage, and comprising actuating means to move the valve members to and keep them in partial capacity positions.
Claim 5
Dependent Claim
59 words
A machine as defined in claim 1, in which the two stages are arranged in side-by-side relationship and the adjustable valve means each include a movable valve member, and including transmission means drivingly interconnecting the rotor pairs at one end of the machine, and actuating means for the movable valve members provided at the other end of the machine.
Claim 6
Dependent Claim
98 words
A machine as defined in claim 4, in which the two stages are high and low pressure stages, each having respective ports, the high pressure port of the low pressure stage and the low pressure port of the high pressure stage being located at the same end of the machine as the transmission means and being in communication with each other through a passage, the movable valve members being interconnected by means of an inextensible flexible member guided by idler pulleys and passing through said passage, one of the movable valve members being connected to said actuating means.
Claim 7
Dependent Claim
39 words
A machine as defined in claim 5, in which said actuating means comprises an hydraulic servo motor of the piston and cylinder type, the piston thereof being operatively connected to the movable valve member of the high pressure stage.
Claim 8
Dependent Claim
15 words
A machine as defined in claim 5, in which the flexible member comprises a chain.
Claim 9
Dependent Claim
28 words
A machine as defined in claim 1, in which means are provided to move the movable valve members towards the low capacity position when the machine is stopped.
References Cited (Backward Citations)
FR804327A
Cited
US2645903A
Cited
US2749571A
Cited
GB819485A
Cited
US3088659A
Cited
US3314597A
Cited
US3432089A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |