Patent US3872887A successfully refreshed from Google Patents.
US3872887A
Expired / Lapsed
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Apparatus for selectively establishing a multiplicity of discrete flow rates
Assignee: Mannesmann Demag Krauss Maffei GmbH
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Filing: 1972-09-05
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Granted: 1975-03-25
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Expires: 1992-09-05
Abstract
Abstract For the selective establishment of a multiplicity of discrete flow rates of a liquid, e.g. of oil in a hydraulic system controlling the delivery of plastic material in an injectionmolding machine, two or more pumps (preferably of different capacity) are connected in parallel between a reservoir or sump and a load, the output of at least the higher-capacity pump being also joined to a bypass path with two or more parallel throttles (preferably of different calibration). The throttles can be individually blocked and the pumps can be individually activated by respective solenoid valves which, when operated in different combinations, may establish different flow rates in the load circuit amounting to, say, 10%, 20%, 30%.....100% of a maximum flow rate available with both pumps active and both throttles blocked.
Inventors
- 👤 Walter Wohlrab
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:08
CPC Classifications
G; G05; G05D; G05D7/00; G05D7/03; G05D7/06; G05D7/0617; G05D7/0629; G05D7/0688; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/85978; Y10T137/86131; Y10T137/86163; Y10T137/87249
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
160 words
A system for selectively establishing a multiplicity of discrete flow rates of a liquid through a load, comprising: a first calibrated constant-flow source of liquid having a relatively low capacity; a second calibrated constant-flow source of liquid having a relatively high capacity; first control means for individually activating and deactivating said sources; constant means with a capacity exceeding that of said second source for supplying the combined outputs of said sources to the load, said conduit means including a first and a second branch respectively connected to said first and said second source; a first and a second calibrated constant-flow fluid sink connected to said second branch for deviating part of the output of said second source from said load upon being placed in an operative condition, said fluid sinks being of different capacity and having a combined capacity less than that of said second source; and second control means for individually rendering said first and second fluid sinks operative.
Claim 2
Independent Claim
160 words
A system for selectively establishing a multiplicity of discrete flow rates of a liquid through a load, comprising: a first calibrated constant-flow source of liquid having a relatively low capacity; a second calibrated constant-flow source of liquid having a relatively high capacity; first control means for individually activating and deactivating said sources; constant means with a capacity exceeding that of said second source for supplying the combined outputs of said sources to the load, said conduit means including a first and a second branch respectively connected to said first and said second source; a first and a second calibrated constant-flow fluid sink connected to said second branch for deviating part of the output of said second source from said load upon being placed in an operative condition, said fluid sinks being of different capacity and having a combined capacity less than that of said second source; and second control means for individually rendering said first and second fluid sinks operative.
Claim 3
Dependent Claim
36 words
A system as defined in claim 1 wherein said fluid sinks are in communication with both said branches, the capacity of at least one of said fluid sinks being less than that of said first source.
Claim 4
Dependent Claim
23 words
A system as defined in claim 1, further comprising check-valve means between said branches for isolating said first source from said fluid sinks.
Claim 5
Dependent Claim
34 words
A system as defined in claim 1 wherein said sources are pumps connected to a supply of liquid, said fluid sinks being restricted passages deverting a part of the pumped liquid from said load.
Claim 6
Dependent Claim
40 words
A system as defined in claim 4 wherein said control means comprises a first set of valves in an individual bypass path for each of said pumps and a second set of valves for individually blocking each of said passages.
Claim 7
Dependent Claim
28 words
A system as defined in claim 5, further comprising a check valve in the output of each of said pumps at a location downstream of said bypass path.
Claim 8
Dependent Claim
22 words
A system as defined in claim 5, further comprising pressure-limiting valve means in said bypass path and in cascade with said passages.
Claim 9
Dependent Claim
33 words
A system as defined in claim 1 wherein the capacities of said sources and fluid sinks have relative numerical values which are multiples mq of a basic magnitude q, m being an integer.
Claim 10
Dependent Claim
15 words
A system as defined in claim 8 wherein said numerical values bear a binary relationship.
Claim 11
Dependent Claim
16 words
A system as defined in claim 8 wherein m is different for all said numerical values.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |