US3680578A - Fluidic control systems - Google Patents

Fluidic control systems Download PDF

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Publication number
US3680578A
US3680578A US78336A US3680578DA US3680578A US 3680578 A US3680578 A US 3680578A US 78336 A US78336 A US 78336A US 3680578D A US3680578D A US 3680578DA US 3680578 A US3680578 A US 3680578A
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United States
Prior art keywords
jet
pressure
power
nozzle
signal
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US78336A
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English (en)
Inventor
Guy Edward Davies
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Plessey Overseas Ltd
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Plessey Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/02—Surge control
    • F04D27/0246—Surge control by varying geometry within the pumps, e.g. by adjusting vanes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15C—FLUID-CIRCUIT ELEMENTS PREDOMINANTLY USED FOR COMPUTING OR CONTROL PURPOSES
    • F15C1/00—Circuit elements having no moving parts
    • F15C1/002—Circuit elements having no moving parts for controlling engines, turbines, compressors (starting, speed regulation, temperature control or the like)
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/206—Flow affected by fluid contact, energy field or coanda effect [e.g., pure fluid device or system]
    • Y10T137/2087—Means to cause rotational flow of fluid [e.g., vortex generator]
    • Y10T137/2093—Plural vortex generators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/206—Flow affected by fluid contact, energy field or coanda effect [e.g., pure fluid device or system]
    • Y10T137/2229—Device including passages having V over T configuration
    • Y10T137/224—With particular characteristics of control input

Definitions

  • bias is, for example, desirable when effecting fluidic control of the variable guide vanes at the inlet to a gas-turbine compressor where, while the required setting of the guide vanes is mainly controlled by the pressure ratio generated across the compressor, it is desirable, in order to avoid surge and to improve the engine control, to bias the guide vanes to the low-speed side of the thus determined position both during rapid acceleration and during rapid deceleration of the engme.
  • bias variable according to a time differential of the value of the input may be produced by applying the input signal to the system via a restrictor and connecting a reservoir to the passage leading from the restrictor to the control system, it will be readily appreciated that the sign of this bias will be dependent on the sign of the time differential of the input signal.
  • FIG. 1 is a circuit diagram of a control system and means for introducing a time lag in the application of an input signal to a fluidic amplifier
  • FIG. 2 is a similar circuit diagram modified to produce a time lead instead of a time lag in the application of the input signal
  • FIG. 3 is a circuit diagram illustrating an embodiment of the present invention applied to one of the control inputs to a conventional proportional fluidic amplifier of the momentum-interaction type
  • FIG. 4 similarly illustrates a modified circuit
  • FIG. 5 diagrammatically illustrates the combination of the system of FIG. 4 with the combustion-air compressor of a gas-turbine engine.
  • a fluidic proportional amplifier A has a power-supply input P, a pair of mutually opposed control-input connections C and C and two output connections and 0 so arranged that the value of the difference in flow and/or pressure between the output connections 0 and 0 is determined by the difference in control pressures between the control-input connections C and C
  • a control signal appearing at a signal input I is applied to controlinput connection C via a restrictor B, and a reservoir chamber D is connected as a branch to the line connecting the restrictor B with the control-input connection C
  • the pressure at input connection C always lags behind variations of signal pressure at I, so that when the signal pressure at I increases, the control pressure at C is temporary lower, and when the signal pressure at I decreases, the control pressure at C, is temporary higher than the signal pressure at I, so that when the pressure at the second control-input connection C is kept constant, the pressure at output 0 will be correspondingly modified.
  • the reversal of the bias according to the sign of the pressure gradient also applies to the circuit of FIG. 2, which causes in a fluidic proportional amplifier A a modulation of the output pressure at 0 to provide a time lead, instead of the time lag obtained by the circuit of FIG. 1, in relation to the control-signal input at I due to the fact that the control signal appearing at input I, in addition to being applied to control-input connection C similarly as described with reference to FIG. 1, is additionally applied via a second restrictor B to a second oppositely acting control-input connection C the inlet of the second restrictor B is also connected to signal-pressure input I, and the outlet of the second restrictor B is directly connected to control-inlet connection C without the provision of a reservoir.
  • the circuit of FIG. 2 will produce no output from amplifier A so long as the signal-input pressure at I remains constant, that rising signal-input pressure at I will cause an increase in the output pressure at 0, since, due to the time lag in the pressure rise at control-input connection C the pressure at the other control-input connection C will exceed that at C and that conversely the output pressure at 0 will be decreased when, and as long as, the input-signal pressure at I decreases, since during such decrease of the input pressure at I the control pressure at C will be somewhat higher, due to additional supply from the reservoir D, than the pressure at the other control-pressure connection C which cannot draw on such an auxiliary supply.
  • the bias will reverse its direction when the sign of the time differential of the pressure signal at input I changes.
  • the illustrated amplifier has a power-supply input 1 leading to a power nozzle 2, and two control-input ports 7 and 8.
  • the power nozzle 2 generates a jet which, in the absence of a control input at ports 7 and 8, is symmetrical to a splitter member 15, by which the jet is divided between two output ports 3 and 4, and two vents 5 and 6 are provided to allow the escape of the excess of the fluid supplied by the jet formed in the nozzle 2 over the amount entering the output ports 3 and 4, more particularly when the latter are closed to obtain a pressure output.
  • the former is shown connected to the throat of a Venturi nozzle 21 which is interposed between a signal-pressure inlet I and a reservoir D, which forms a pressure-energy storage capacitor.
  • a signal-pressure inlet I is interposed between a signal-pressure inlet I and a reservoir D, which forms a pressure-energy storage capacitor.
  • the other control port 8 may be connected to the signal pressure inlet I, when the control is intended to produce only a transient control, or to vent or other reference pressure or control pressure when the control is intended to be also influenced by the steady value of the signal pressure I.
  • the thus biased output pressure may be applied to a spring-biased servomotor cylinder 22, whose piston 23 acts through a link rod 24 upon a crank 25 provided on the compressor housing 26 of a turbo-compressor to operate variable-angle guide vanes in the compressor portion of the turbo-compressor T.
  • FIG. 4 shows an arrangement in which the invention is used in this manner in conjunction with a proportional amplified 18 which, in order to facilitate this, has a modulated input which is described in more detail in co-pending application Ser. No. 68,965, filed Sept. 2, 1970 corresponding to British patent application No. 44707/69.
  • the output of that amplifier 18 is employed as the normal control input of a further amplifier stage 18A.
  • the mass flow of the power jet becomes a function of the signal pressure
  • the bias action of the Venturi nozzle is effective to modify the output of the amplifier 18 by altering, in response to variations of the signal pressure at inlet I, the distribution between the two branch nozzles 2A and 28 while the two main control nozzles 7 and 8 of the amplifier 18 are left free for other control actions.
  • a pressure input which may be the same source as that connected to I, is applied to one main control nozzle 7 from a point 17 via a planar jet collector 16.
  • the housing of this collector may be vented, for example to the environmental atmosphere, or connected to some other reference pressure, so that the pressure effective at control port 7 forms a function of that reference pressure as well as of the pressure applied at 17; the other main control nozzle 8 may be connected to a reference-signal or pressure at a connection point 10.
  • FIG. 4 may, similarly to that of FIG. 3, be used to control an actuator cylinder for the operation of, for example, variable-angle guide vanes in the compressor portion of a turbo-compressor, the servomotor cylinder being, for this purpose, connected to the two outputs of the second-stage amplifier 18A in the same way in which the outputs 3 and 4 of the amplifier 18 are connected in FIG. 3.
  • FIG. 5 Such an arrangement is illustrated in FIG. 5, in which the same references as in the preceding Figures have been used for corresponding parts.
  • the compressor portion 26 of a gas turbine engine which is fed with ambient air at a pressure P,, and its delivery pressure P, is supplied to the input 1 of the fluidic amplifier 18.
  • This air under pressure P is also fed to the power input of the secondstage amplifier 18A and to two other branch lines, of which one leads to the input of the planar jet collector 16, whose body has an atmospheric vent at ambient pressure P, and whose output is connected to one main control nozzle 7 of the first-stage amplifier l8,-while the other branch leads, via two series-connected restrictors X and X of which the former has a fixedarea aperture while the latter is adjustable by a lever 31, to an opening exposed to ambient pressure P, and has, between the restrictors X, and X2, 8 tapping 27 connected at 10 to the other main-control nozzle of the first-stage amplifier l8.
  • the pressures respectively acting at the inlets to control nozzles 7 and 8 will both lie between the values of P and P, but will, for a given setting of the adjustable restrictor X correspond to different functions of P, and P, (or for a given P, to different functions of P They can, at least when the apparatus is suitably dimensioned, be made equal, at any given values of P, and P,,by suitable adjustment of the orifice X subject to the effect of the Venturi-controlled twin-jet arrangement 2A, 2B.
  • the latter arrangement introduces the time difierential of the compressor-delivery pressure and is employed, as will be seen further below, to counteract an excessive rate of rise of the compressor-delivery pressure and the inherent risk of compressor stall.
  • the output lines 3 and 4 of the first-stage amplifier 18 are connected respectively to the control nozzles 8A and 7A of the secondstage amplifier 18A, while theoutput lines 3A and 4A of the latter amplifier are respectively connected to the two ends of an. actuator cylinder 22,. whose piston 23 acts through its piston rod 24 and a linkage 28, 29 upon a crank member 25 to vary the setting of the inlet guide vanes 25 (which, as shown near the top of the Figure, form part of the compressor 26) about their fulcra 25A as required by, varying pressure conditions, while a feedback mechanism 30 acts upon the lever 31 of the adjustable restrictor X so as to restore pressure balance between the control nozzles 7 and 8 of the first-stage amplifier 18 after appropriate movement of the guide vanes.
  • Venturi nozzle 12 is of symmetrical construction, which results in equal bias for equal and opposite rates of input-pressure variation
  • a Venturi nozzle of asymmetrical construction may alternatively be employed, thus causing the amount of bias to depend on the sign of the pressure variation. If, for example, the fluid-expansion ratio between the throat and the reservoir is increased, the response to a rising pressure will be greater than to a falling pressure.
  • the apparatus mentioned has been hereinabove described for operation on compressible gases, it can be readily modified to work satisfactorily on liquid subject to certain differences which will be readily apparent to those skilled in the art, and which include inter alia the fact that in practice choking, which may be utilized with a gaseous fluid to keep the total flow through the fixed-area throttle X, constant, will not occur in a system operating with hydraulic liquid at any practically occurring pressure ratio.
  • the reservoir completely filled with operating fluid may be replaced by a hydraulic accumulator, which may comprise a free piston acted-upon by the pressure of the hydraulic liquid and acting against a spring, or alternatively the accumulator may include a pressurizing chamber containing gas under pressure which may for example, as indicated in broken lines in FIG. 3, be isolated by a diaphragm 27 from the operating liquid against whose pressure it acts.
  • a flu'dic control aratus co ri in l. a jet-interaction fliel zlic proport i h a iphfier having an interaction chamber, a power-jet nozzle for projecting a power jet of fluid into said chamber, a jet splitter facing said nozzle across said chamber, two output passages extending from said chamber along opposite sides respectively of said jet splitter, and a further jet nozzle for projecting into said chamber a further jet impinging upon the power jet in the chamber at an angle to the power jet to deflect the power jet away from one and towards the other of said output passages, and
  • a signal-pressure differentiation line having a signal-input aperture at one end and a pressureenergy storage capacitor connected to its other end and including, between said ends, a Venturi nozzle having a throat and a tapping located at least in the vicinity of said throat, said tapping being connected to said further jet nozzle to provide the supply of fluid for such further jet.
  • said further nozzle is a second power-jet nozzle arranged with its axis intersecting the axis of the first-mentioned power-jet nozzle to produce a second power jet which merges with the power jet produced by said first-mentioned power-jet nozzle to form a composite power jet of a direction intermediate between the respective directions of said power jet and second power jet.
  • Apparatus as claimed in claim 2 including a substantially free connection from said signal-input aperture to said second power-jet nozzle.
  • Apparatus as claimed in claim 1 which includes a fluid-pressure operated actuator having an operating chamber the pressure in which is controlled by the pressure in one of said output passages.
  • Apparatus as claimed in claim 1 which includes an actuator having a piston acted-upon in opposite directions by the respective pressures in said output passages.
  • a fluidic control apparatus comprising 1. a jet-interaction fluidic proportional amplifier having an interaction chamber, a power-jet nozzle for projecting a power jet of fluid into said chamber, a jet splitter facing said nozzle across said chamber, two output passages extending from said chamber along opposite sides respectively of said jet splitter, and a control-jet nozzle for projecting into said chamber a control jet impinging upon the power jet in the chamber transversely to the power jet to deflect the power jet away from one and towards the other of said output passages, and
  • a signal-pressure differentiation line having a signal-input aperture at one end and a pressureenergy storage capacitor connected to its other end and including, between said ends, a Venturi nozzle having a throat and a tapping located at least in the vicinity of said throat, said tapping being connected to said control-jet nozzle to provide the supply of fluid for such control jet.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Fluid Mechanics (AREA)
  • Theoretical Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Geometry (AREA)
  • Jet Pumps And Other Pumps (AREA)
  • Supercharger (AREA)
  • Control Of Non-Electrical Variables (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Servomotors (AREA)
  • Control Of Fluid Pressure (AREA)
US78336A 1969-09-10 1970-09-02 Fluidic control systems Expired - Lifetime US3680578A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4470869 1969-09-10

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US3680578A true US3680578A (en) 1972-08-01

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US78336A Expired - Lifetime US3680578A (en) 1969-09-10 1970-09-02 Fluidic control systems

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US (1) US3680578A (de)
JP (1) JPS5023116B1 (de)
DE (1) DE2044912C3 (de)
FR (1) FR2061636B1 (de)
GB (1) GB1304010A (de)
SE (1) SE364128B (de)
SU (1) SU440002A3 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3771388A (en) * 1970-12-21 1973-11-13 Toyota Motor Co Ltd Fluid control system for automatic vehicle transmissions
US4164961A (en) * 1977-07-28 1979-08-21 The United States Of America As Represented By The Secretary Of The Army Fluidic pressure/flow regulator
US20060024180A1 (en) * 2004-07-28 2006-02-02 Lane Glenn H Fluidic compressor
EP3434914A1 (de) * 2017-07-25 2019-01-30 Rolls-Royce plc Strömungsvorrichtung

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1511723A (en) * 1975-05-01 1978-05-24 Rolls Royce Variable stator vane actuating mechanism
US4252498A (en) * 1978-03-14 1981-02-24 Rolls-Royce Limited Control systems for multi-stage axial flow compressors
RU171014U1 (ru) * 2016-10-03 2017-05-17 Открытое акционерное общество "Омское машиностроительное конструкторское бюро" Устройство управления положением лопаток регулируемого направляющего аппарата

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3400729A (en) * 1965-04-01 1968-09-10 Gen Electric Rate of change of pressure sensor
US3474959A (en) * 1967-06-19 1969-10-28 Us Army Fluid analog circuits
US3528443A (en) * 1968-06-04 1970-09-15 Us Army Fluid induction nor gate
US3542048A (en) * 1967-10-18 1970-11-24 Romald E Bowles Self-adaptive systems
US3552415A (en) * 1969-04-03 1971-01-05 Corning Glass Works Jet entrainment control for a fluidic device
US3572357A (en) * 1968-12-10 1971-03-23 Robertshaw Controls Co Engine monitoring system employing fluidic circuitry
US3590840A (en) * 1968-05-29 1971-07-06 Bendix Corp Fluidic control apparatus

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3400729A (en) * 1965-04-01 1968-09-10 Gen Electric Rate of change of pressure sensor
US3474959A (en) * 1967-06-19 1969-10-28 Us Army Fluid analog circuits
US3542048A (en) * 1967-10-18 1970-11-24 Romald E Bowles Self-adaptive systems
US3590840A (en) * 1968-05-29 1971-07-06 Bendix Corp Fluidic control apparatus
US3528443A (en) * 1968-06-04 1970-09-15 Us Army Fluid induction nor gate
US3572357A (en) * 1968-12-10 1971-03-23 Robertshaw Controls Co Engine monitoring system employing fluidic circuitry
US3552415A (en) * 1969-04-03 1971-01-05 Corning Glass Works Jet entrainment control for a fluidic device

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3771388A (en) * 1970-12-21 1973-11-13 Toyota Motor Co Ltd Fluid control system for automatic vehicle transmissions
US4164961A (en) * 1977-07-28 1979-08-21 The United States Of America As Represented By The Secretary Of The Army Fluidic pressure/flow regulator
US20060024180A1 (en) * 2004-07-28 2006-02-02 Lane Glenn H Fluidic compressor
US7413418B2 (en) 2004-07-28 2008-08-19 Honeywell International, Inc. Fluidic compressor
EP3434914A1 (de) * 2017-07-25 2019-01-30 Rolls-Royce plc Strömungsvorrichtung

Also Published As

Publication number Publication date
JPS5023116B1 (de) 1975-08-05
SE364128B (de) 1974-02-11
FR2061636A1 (de) 1971-06-25
DE2044912B2 (de) 1979-05-23
FR2061636B1 (de) 1975-01-10
DE2044912C3 (de) 1980-02-07
DE2044912A1 (de) 1971-03-11
GB1304010A (de) 1973-01-24
SU440002A3 (ru) 1974-08-15

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Owner name: PLESSEY OVERSEAS LIMITED

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:PLESSEY COMPANY LIMITED THE;REEL/FRAME:003962/0736

Effective date: 19810901