US3717166A - Pure fluidic devices - Google Patents

Pure fluidic devices Download PDF

Info

Publication number
US3717166A
US3717166A US00142165A US3717166DA US3717166A US 3717166 A US3717166 A US 3717166A US 00142165 A US00142165 A US 00142165A US 3717166D A US3717166D A US 3717166DA US 3717166 A US3717166 A US 3717166A
Authority
US
United States
Prior art keywords
inlet
outlet
switch
branch
venturi
Prior art date
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
Application number
US00142165A
Other languages
English (en)
Inventor
G Davies
C Wilson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Plessey Overseas Ltd
Original Assignee
Plessey Handel und Investments AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Plessey Handel und Investments AG filed Critical Plessey Handel und Investments AG
Application granted granted Critical
Publication of US3717166A publication Critical patent/US3717166A/en
Assigned to PLESSEY OVERSEAS LIMITED reassignment PLESSEY OVERSEAS LIMITED ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: PLESSEY HANDEL UND INVESTMENTS AG, GARTENSTRASSE 2, ZUG, SWITZERLAND
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • F15C1/22—Oscillators
    • 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]
    • Y10T137/212—System comprising plural fluidic devices or stages

Definitions

  • ABSTRACT The two outlet branches of a bistable wall-adhesion May 15,1970 Great Bntam ..23,67l/70 amplifier are each connected through a Venturi to a capacitor volume chamber, while the throat of each [2%] $5.31 venturi is coupled back to that comm] Met of the 6f "ii.
  • the two outlet branches of a Coanda-type bistable fluidic switch are each connected through a Venturi nozzle to a capacitor chamber, and the throat of the Venturi nozzle in each branch is connected to that control inlet of the Coanda switch which when pressurized tends to switch the output flow to the other outlet branch.
  • FIG. 1 is a circuit diagram of one oscillator device according to the invention
  • FIG. 2 is a fragmentary diagram illustrating the operation of one of the branches
  • FIGS. 3a and 3b show two waveforms respectively obtainable at the throat of the Venturi of FIG. 2 by a positive-change and a negative-change input-pressure step respectively illustrated in FIGS. 30 and 3d,
  • FIG. 4 shows three different output waveforms A, B, C, available at the throat of the Venturi of FIG. 2 in response to a square-wave input by variation of the position of the throat tapping in the Venturi, and
  • FIG. 5 shows two pressure waveforms PO, and P0 respectively available at the tappings of the Venturi in each branch of the circuit, and a sawtooth waveform available as the pressure difference between these two tappings, while a square waveform similar to that shown at O in FIG. 4 is available as the pressure difference between the inlet ends of the two Venturis.
  • the illustrated oscillator device consists of the following pure fluidic components, which are connected up as shown to form an integrated fluidic circuit.
  • integrated fluidic circuit when used in this specification, is intended to refer to a fluidic circuit all parts of which are formed in a common integral block of material.
  • a bistable Coanda-type fluidic switch 1 has a power inlet 9 for connection to a source of compressible fluid under pressure, and each of its two output branches 7 and 8 is connected via a Venturi 3 to a chamber 4 constituting a fluidic capacitor 4, while the throat of the Venturi 3 in each output branch is connected by a line 10 to that control inlet of the switch 1 which tends to divert the main flow from power inlet 9 to the other outlet branch.
  • FIG. 2 The basic configuration of such a combination is shown in FIG. 2.
  • An input of compressible fluid whose pressure P is subject to variation in rectangular steps; is supplied to the Venturi 3 at 5, and an output P is tapped-off at a position 6 close to the throat of the venturi 3.
  • the waveforms 7 and 8 shown respectively in FIGS. 3a and 3b illustrate the respective outputs obtained from the circuit following a step of change in the pressure P according to whether the step is positive as shown in FIG. 3c or negative as shown in FIG. 3d.
  • Comparison of the waveforms respectively shown in FIGS. 3a and 3b shows that it is possible to obtain two different time constants r, and T for positive and negative changes of equal magnitude in the applied pressure P so that various output waveforms may be produced by subjecting the circuit to a pulsating signal.
  • the waveforms shown at A, B and C in FIG. 4 are all obtained in response to a square-wave input pressure P as shown at O, the differences in the waveforms A, B and C being due to variation of the tapping point 6 along the Venturi 3; the action of the Venturi in this combination is to provide a derivative signal in response to a step input.
  • the characteristics described may be utilized to obtain a fluidic oscillator the output waveform of which may be varied as indicated by waveforms A, B and C of FIG. 4. (N.P.)
  • the basic circuit for one form of such an oscillator is described above and illustrated in FIG. 1.
  • This circuit provides a saw-tooth oscillator supplying, as the pressure difference between the Venturi tappings 10 and 11, an extremely well defined saw-tooth waveform, but the same circuit can also be used to provide a square-wave oscillator of extremely well defined waveform by deriving the output from the pressure difference between the two outlets of the Coanda switch I.
  • the output frequency of oscillators employing these techniques is determined by the product RC, in which the value C is defined by the volume of capacitor 4 and the value R is defined by the throat dimensions of the Venturi 3.
  • the operation of the circuits described is as follows:
  • the circuit of FIG. 1 is unstable due to the positive feedback to the bistable switch 1. Having switched to one of its output branches 7, 8, the power jet coming from inlet 9 will be retained in this position by wall attachment until the flow through this output branch has charged its capacitor reservoir 4 or 5 to a pressure at which the control pressure at the Venturi throat tapping 10 or 11 is sufficient to switch the power jet to the opposite output leg. Similar action will then be repeated on the other output branch, and the periodic operation is self-sustaining. Thus an oscillatory output is produced which is believed to make the oscillator capable of performing at higher pressure ratios than those commonly associated with fluidic devices.
  • Venturi in each leg may be said to enable an inductive term to be added to the RC network, thereby producing very positive switching of the bistable device and generating, in the case of a square-wave oscillator, a very clearly defined square waveform.
  • Another advantage of the oscillators according to the invention is that they can be made to function over a wide range of pressure ratios with only a slight shift in basic frequency.
  • FIG. 5 illustrated three different waveforms D, E AND F, obtainable from the device illustrated in FIG. 1.
  • E and first two waveforms D and E represent the pressures respectively obtained at the tappings l0 and 11 of the two Venturi nozzles 3, while the third waveform F is obtained as the difference between these pressures.
  • a further output of square waveform is obtainable as the difference between the pressures at two tappings I2 and 13 provided respectively at the inlet ends of the two Venturi nozzles 3.
  • Pulse-width modulation circuits provide an immediate application for a device where an accurate sawtooth or triangular wave profile is a prime requisite.
  • the apparatus described may be modified within the scope of the invention. Thus though generally preferred, it is not essential for it to be made in one integral block of material.
  • a pure fluidic oscillator comprising: a Coandatype switch having a power inlet for producing a power jet, a first and a second outlet branch, and a first and a second control inlet respectively associated with each branch and respectively operative when pressurized to cause the power jet to be switched-over to the other branch; a first and a second Venturi nozzle each having an inlet, an outlet and a nozzle passage forming a throat and leading from said inlet through said throat to said outlets, said nozzle passage being provided with a tapping in said throat; and a first and a second capacitor receptacle the first Venturi nozzle having its inlet connected to the first outlet branch of the switch, its outlet connected to the first capacitor receptacle, and its tapping connected to the first control inlet of the switch, and the second Venturi nozzle having its inlet connected to the second outlet branch of the switch, its outlet connected to the second capacity receptacle, and its tapping connected to the second control inlet of the switch, and the oscillator being provided with output
  • An oscillator as claimed in claim 1 which is provided with two output connections respectively subject to the pressure at the tapping of each Venturi nozzle.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Measuring Volume Flow (AREA)
  • Jet Pumps And Other Pumps (AREA)
US00142165A 1970-05-15 1971-05-11 Pure fluidic devices Expired - Lifetime US3717166A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2367170 1970-05-15

Publications (1)

Publication Number Publication Date
US3717166A true US3717166A (en) 1973-02-20

Family

ID=10199401

Family Applications (1)

Application Number Title Priority Date Filing Date
US00142165A Expired - Lifetime US3717166A (en) 1970-05-15 1971-05-11 Pure fluidic devices

Country Status (4)

Country Link
US (1) US3717166A (enrdf_load_stackoverflow)
DE (1) DE2124162C3 (enrdf_load_stackoverflow)
FR (1) FR2090049B1 (enrdf_load_stackoverflow)
GB (1) GB1343403A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140262131A1 (en) * 2013-03-15 2014-09-18 Chart Inc. Cooling of cryogenic meters sensing reverse flow
EP3434914A1 (en) * 2017-07-25 2019-01-30 Rolls-Royce plc Fluidic device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5165438A (en) * 1992-05-26 1992-11-24 Facteau David M Fluidic oscillator

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3429324A (en) * 1965-02-16 1969-02-25 Corning Glass Works Fluid operated apparatus
US3444879A (en) * 1967-06-09 1969-05-20 Corning Glass Works Fluid pulsed oscillator
US3515158A (en) * 1967-11-24 1970-06-02 Us Navy Pure fluidic flow regulating system
US3528442A (en) * 1967-07-14 1970-09-15 Us Army Fluid modulator system
US3557815A (en) * 1967-08-28 1971-01-26 Honeywell Inc Control apparatus
US3575187A (en) * 1968-06-13 1971-04-20 Garrett Corp Fluidic pressure-insensitive oscillator
US3576294A (en) * 1969-02-26 1971-04-27 Bendix Corp Fluidic cleansing device
US3605778A (en) * 1969-03-04 1971-09-20 Bowles Fluidics Corp Variable delay line oscillator
US3628774A (en) * 1971-03-17 1971-12-21 Bendix Corp Fluidic fluid-metering system
US3633160A (en) * 1969-11-10 1972-01-04 Gen Motors Corp Warning-lamp pulsator

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3429324A (en) * 1965-02-16 1969-02-25 Corning Glass Works Fluid operated apparatus
US3444879A (en) * 1967-06-09 1969-05-20 Corning Glass Works Fluid pulsed oscillator
US3528442A (en) * 1967-07-14 1970-09-15 Us Army Fluid modulator system
US3557815A (en) * 1967-08-28 1971-01-26 Honeywell Inc Control apparatus
US3515158A (en) * 1967-11-24 1970-06-02 Us Navy Pure fluidic flow regulating system
US3575187A (en) * 1968-06-13 1971-04-20 Garrett Corp Fluidic pressure-insensitive oscillator
US3576294A (en) * 1969-02-26 1971-04-27 Bendix Corp Fluidic cleansing device
US3605778A (en) * 1969-03-04 1971-09-20 Bowles Fluidics Corp Variable delay line oscillator
US3633160A (en) * 1969-11-10 1972-01-04 Gen Motors Corp Warning-lamp pulsator
US3628774A (en) * 1971-03-17 1971-12-21 Bendix Corp Fluidic fluid-metering system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140262131A1 (en) * 2013-03-15 2014-09-18 Chart Inc. Cooling of cryogenic meters sensing reverse flow
US10288367B2 (en) * 2013-03-15 2019-05-14 Chart, Inc Cooling of cryogenic meters sensing reverse flow
EP3434914A1 (en) * 2017-07-25 2019-01-30 Rolls-Royce plc Fluidic device

Also Published As

Publication number Publication date
FR2090049B1 (enrdf_load_stackoverflow) 1976-02-06
GB1343403A (en) 1974-01-10
DE2124162C3 (de) 1980-03-27
DE2124162A1 (de) 1971-11-25
FR2090049A1 (enrdf_load_stackoverflow) 1972-01-14
DE2124162B2 (de) 1979-07-19

Similar Documents

Publication Publication Date Title
US3228410A (en) Fluid pulse width modulation
IT1075714B (it) Mobile per esterno,particolarmente sedile o tavolo da giardino
US3717166A (en) Pure fluidic devices
US3479440A (en) Randomly-perturbed,locked-wave generator
FR2401581A1 (fr) Emetteur de telecommande
US3472256A (en) Fluidic diodes
US3320966A (en) Fluid oscillator
US3434487A (en) High frequency proportional fluid amplifier
GB1492071A (en) Fluid logic system
GB1239065A (enrdf_load_stackoverflow)
US3437099A (en) Pulse generator
US3442281A (en) Constant frequency fluid pulse system
US3557815A (en) Control apparatus
GB1036563A (en) Voltage to frequency transducer
SU532094A1 (ru) Струйное устройство сравнени
US3463177A (en) Fluidic frequency discriminator
US3722521A (en) Fluidic apparatus more particularly for the determination of pressureratios
US3513867A (en) Tuned and regenerative flueric amplifiers
GB1304895A (enrdf_load_stackoverflow)
US3148692A (en) Bistable fluid device
GB1187685A (en) Improvements in or relating to Fluidic Switching Signal Generators and Bistable Fluidic Arrangements incorporating these Generators
US3568699A (en) Leading and/or trailing edge pulse shaper
US3451408A (en) Control apparatus
GB1213871A (en) A binary fluid divider
US3712323A (en) Fluidic half-adder