Patent US3936041A successfully refreshed from Google Patents.
Patent US4437307A successfully refreshed from Google Patents.
US4437307A
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US
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Priority flow control system
Assignee: Caterpillar Inc
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Filing: 1982-03-11
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Granted: 1984-03-20
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Expires: 2002-03-11
Abstract
Abstract A priority flow control system in which the priority feature is obtained by progressively lowering the pressure differential of nonpriority valves, once the maximum pump output is reached, so that all of the system valves always retain their compensated proportional flow feature.
Inventors
- 👤 Tadeusz Budzich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:07
CPC Classifications
F; F15; F15B; F15B11/00; F15B11/16; F15B11/161; F15B11/162; F15B11/163; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/2053; F15B2211/30; F15B2211/305; F15B2211/30525; F15B2211/3053; F15B2211/30535; F15B2211/50; F15B2211/505; F15B2211/50509; F15B2211/50536; F15B2211/57; F15B2211/60; F15B2211/605; F15B2211/6051; F15B2211/6052; F15B2211/65; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/87169; Y10T137/87177; Y10T137/87185; Y10T137/87233
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
188 words
A priority flow control system supplied from a source of pressure fluid and connected to exhaust means said priority flow control system including a priority valve assembly operable to control a load and at least one other valve assembly said other valve assembly having a housing connected to a fluid motor, control orifice means in said housing interposed between said source of pressure fluid and said fluid motor, fluid flow control means in said housing, first control means operable through said fluid flow control means to maintain a pressure differential across said control orifice means at a controlled constant level, and second control means having first means responsive to maximum fluid flow from said source of pressure fluid and second means operable through said fluid flow control means and said first control means to vary the level of said constant pressure differential whereby the level of said constant pressure differential can be progressively lowered by said second means once fluid flow from said source of pressure fluid will approach its maximum flow output and flow demand of said priority flow control system will exceed said maximum flow output.
Claim 2
Dependent Claim
188 words
A priority flow control system supplied from a source of pressure fluid and connected to exhaust means said priority flow control system including a priority valve assembly operable to control a load and at least one other valve assembly said other valve assembly having a housing connected to a fluid motor, control orifice means in said housing interposed between said source of pressure fluid and said fluid motor, fluid flow control means in said housing, first control means operable through said fluid flow control means to maintain a pressure differential across said control orifice means at a controlled constant level, and second control means having first means responsive to maximum fluid flow from said source of pressure fluid and second means operable through said fluid flow control means and said first control means to vary the level of said constant pressure differential whereby the level of said constant pressure differential can be progressively lowered by said second means once fluid flow from said source of pressure fluid will approach its maximum flow output and flow demand of said priority flow control system will exceed said maximum flow output.
Claim 3
Dependent Claim
27 words
A priority flow control system as set forth in claim 1 wherein said source of pressure fluid includes a pump provided with a load sensing flow control.
Claim 4
Dependent Claim
36 words
A priority flow control system as set forth in claim 2 wherein said first means responsive to maximum fluid flow has means responsive to pressure differential developed across said load sensing flow control of said pump.
Claim 5
Dependent Claim
32 words
A priority flow control system as set forth in claim 1 wherein said first means responsive to maximum fluid flow has means responsive to pressure differential developed across said priority valve assembly.
Claim 6
Dependent Claim
41 words
A priority flow control system as set forth in claim 1 wherein said first means responsive to maximum fluid flow has means responsive to pressure differential across orifice means interposed between said source of pressure fluid and said priority control system.
Claim 7
Dependent Claim
24 words
A priority flow control system as set forth in claim 1 wherein said fluid flow control means includes fluid throttling means having actuating means.
Claim 8
Dependent Claim
29 words
A priority flow control system as set forth in claim 6 wherein said first means responsive to maximum fluid flow has means responsive to pressure in said actuating means.
Claim 9
Dependent Claim
21 words
A priority flow control system as set forth in claim 1 wherein said first control means includes amplifying pilot valve means.
Claim 10
Dependent Claim
21 words
A priority flow control system as set forth in claim 1 wherein said second means includes load pressure signal throttling means.
Claim 11
Dependent Claim
37 words
A priority flow control system as set forth in claim 1 wherein said priority valve assembly includes control orifice means and fluid flow control means operable to maintain a constant pressure differential across said control orifice means.
Claim 12
Dependent Claim
188 words
A priority flow control system supplied from a pump provided with load responsive flow control said priority flow control system including a priority valve assembly operable to control a load and at least one other valve assembly operable to control fluid flow to and from a fluid motor subjected to a load, said other valve assembly having first valve means operable to meter fluid flow of said motor, throttling fluid flow control means operable to throttle fluid flow of said motor, pilot valve means having means responsive to a load pressure related control signal and operable through said throttling fluid flow control means to maintain a constant pressure differential at a preselected constant level across said pilot valve means and to maintain a constant pressure differential across said first valve means during control of said load, and controller means having means responsive to the maximum flow out of said pump and means operable to modify said load pressure related control signal, whereby the level of said constant pressure differential acting across said first valve means can be progressively lowered once said pump reaches its maximum flow output level.
Claim 13
Dependent Claim
188 words
A priority flow control system supplied from a pump provided with load responsive flow control said priority flow control system including a priority valve assembly operable to control a load and at least one other valve assembly operable to control fluid flow to and from a fluid motor subjected to a load, said other valve assembly having first valve means operable to meter fluid flow of said motor, throttling fluid flow control means operable to throttle fluid flow of said motor, pilot valve means having means responsive to a load pressure related control signal and operable through said throttling fluid flow control means to maintain a constant pressure differential at a preselected constant level across said pilot valve means and to maintain a constant pressure differential across said first valve means during control of said load, and controller means having means responsive to the maximum flow out of said pump and means operable to modify said load pressure related control signal, whereby the level of said constant pressure differential acting across said first valve means can be progressively lowered once said pump reaches its maximum flow output level.
Claim 14
Dependent Claim
178 words
A flow control system supplied from a source of pressure fluid and connected to exhaust means said flow control system including at least one valve assembly operable to control a load said valve assembly having a housing connected to a fluid motor, control orifice means in said housing interposed between said source of pressure fluid and said fluid motor, fluid flow control means in said housing, first control means operable through said fluid flow control means to maintain a pressure differential across said control orifice means at a controlled constant level, and second control means having first means responsive to maximum fluid flow from said source of pressure fluid and second means operable through said fluid flow control means and said first control means to vary the level of said constant pressure differential whereby the level of said constant pressure differential can be progressively lowered by said second means once fluid flow from said source of pressure fluid will approach its maximum flow output and flow demand of said flow control system will exceed said maximum flow output.
Claim 15
Dependent Claim
178 words
A flow control system supplied from a source of pressure fluid and connected to exhaust means said flow control system including at least one valve assembly operable to control a load said valve assembly having a housing connected to a fluid motor, control orifice means in said housing interposed between said source of pressure fluid and said fluid motor, fluid flow control means in said housing, first control means operable through said fluid flow control means to maintain a pressure differential across said control orifice means at a controlled constant level, and second control means having first means responsive to maximum fluid flow from said source of pressure fluid and second means operable through said fluid flow control means and said first control means to vary the level of said constant pressure differential whereby the level of said constant pressure differential can be progressively lowered by said second means once fluid flow from said source of pressure fluid will approach its maximum flow output and flow demand of said flow control system will exceed said maximum flow output.
Claim 16
Dependent Claim
26 words
A flow control system as set forth in claim 12 wherein said source of pressure fluid includes a pump provided with a load sensing flow control.
Claim 17
Dependent Claim
35 words
A flow control system as set forth in claim 13 wherein said first means responsive to maximum fluid flow has means responsive to pressure differential developed across said load sensing flow control of said pump.
Claim 18
Dependent Claim
40 words
A flow control system as set forth in claim 12 wherein said first means responsive to maximum fluid flow has means responsive to pressure differential across orifice means interposed between said source of pressure fluid and said flow control system.
Claim 19
Dependent Claim
23 words
A flow control system as set forth in claim 12 wherein said fluid flow control means includes fluid throttling means having actuating means.
Claim 20
Dependent Claim
20 words
A flow control system as set forth in claim 12 wherein said first control means includes amplifying pilot valve means.
Claim 21
Dependent Claim
20 words
A flow control system as set forth in claim 12 wherein said second means includes load pressure signal throttling means.
References Cited (Backward Citations)
US3768372A
Cited
US4282898A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-20 | 1987-09-19 | 1988-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-20 | 1991-09-19 | 1992-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-20 | 1995-09-19 | 1996-03-20 | $7700.00 | Window Closed / Lapsed |