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US3411520A - Maximum pressure selector - Google Patents

Maximum pressure selector Download PDF

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Publication number
US3411520A
US3411520A US386492A US38649264A US3411520A US 3411520 A US3411520 A US 3411520A US 386492 A US386492 A US 386492A US 38649264 A US38649264 A US 38649264A US 3411520 A US3411520 A US 3411520A
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United States
Prior art keywords
pressure
input
passages
passage
orifice
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Expired - Lifetime
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US386492A
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English (en)
Inventor
Romald E Bowles
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Individual
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Individual
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Priority to US386492A priority Critical patent/US3411520A/en
Priority to GB28227/65A priority patent/GB1117470A/en
Priority to DE19651523458 priority patent/DE1523458B2/de
Priority to DE19651774975 priority patent/DE1774975B2/de
Application granted granted Critical
Publication of US3411520A publication Critical patent/US3411520A/en
Anticipated expiration legal-status Critical
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    • 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
    • F15C1/14—Stream-interaction devices; Momentum-exchange devices, e.g. operating by exchange between two orthogonal fluid jets ; Proportional amplifiers
    • F15C1/143—Stream-interaction devices; Momentum-exchange devices, e.g. operating by exchange between two orthogonal fluid jets ; Proportional amplifiers for digital operation, e.g. to form a logical flip-flop, OR-gate, NOR-gate, AND-gate
    • 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
    • F15C1/02—Details, e.g. special constructional devices for circuits with fluid elements, such as resistances, capacitive circuit elements; devices preventing reaction coupling in composite elements ; Switch boards; Programme devices
    • F15C1/06—Constructional details; Selection of specified materials ; Constructional realisation of one single element; Canal shapes; Jet nozzles; Assembling an element with other devices, only if the element forms the main part
    • 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
    • F15C1/14—Stream-interaction devices; Momentum-exchange devices, e.g. operating by exchange between two orthogonal fluid jets ; Proportional amplifiers
    • 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]
    • Y10T137/2164—Plural power inputs to single device
    • Y10T137/2169—Intersecting at interaction region [e.g., comparator]

Definitions

  • the present invention relates to pressure selector apparatus and, more particularly, to a pure fluid pressure selector apparatus for producing an output signal having a pressure substantially equal to the highest pressure of a plurality of distinct input pressures applied to the apparatus.
  • FIGURE 1 is a diagram illustrating One form of appaatus of the present invention
  • FIGURE 2 is a diagram illustrating fluid stream characteristics which must be considered in developing a maximum pressure selector in accordance with the present invention
  • FIGURE 3 is a diagram illustrating some of the principles of the apparatus of FIGURE 1
  • FIGURES 4a and 4b are flow diagrams illustrating changes in flow patterns of intersecting streams;
  • FIGURE 5 is a diagram illustrating a four-way rectifier circuit employing the maximum pressure recovery unit of the present invention.
  • FIGURE 6 is a diagram illustrating a maximum pressure recovery unit having three input signals.
  • FIGURE 1 of the accompanying drawings there is illustrated a maximum pressure selector generally designated by the reference numeral 1 and having a pair of input passages 2 and 3 formed as channels in a solid block of material 4.
  • the passages 2 and 3 are supplied through appropriate apertures 6 and 7 which pass through the bottom of the block 4 as illustrated in FIGURE 1.
  • the centerlines of the passages 2 and 3 converge and meet at a point 8 which, in the particular configuration illustrated, is at the entrance to asingle output passage 9 also formed as a channel on the block 4.
  • the space intermediate the outlet orifice of passages 2 and 3 and inlet orifice of the passage 8 is recessed to the depth of the passages and is confined between a wall 11 of the body 4 and top or cover plate 12.
  • the plate 12 is illustrated in broken lines.
  • FIG. URE 1 Certain parameters of the apparatus illustrated in FIG- URE 1 are critical and initially reference is made to FIGURE 2 of the accompanying drawings.
  • a nozzle 13 issues a stream of fluid to the right. While the fluid is in the nozzle or passage 13, substantially all of the fluid is at the same dynamic pressure. Upon leaving the nozzle, the fluid begins to entrain fluid surrounding the stream and, since this fluid is at a lower velocity, averaging causes the dynamic pressure to fall.
  • a triangle 14 having a base equal to the width of the nozzle and having two equal-length legs. The triangle 14 illustrates the region of the stream in which the dynamic pressures of the stream is equal to the initial dynamic pressure; that is, the pressure of the fluid in the nozzle 13. In ordinary situations such as an air stream traveling through a region of ambient air, the region of initial pressure converges as indicated by the triangle 14 and the apex of th triangle lies about six widths of the nozzle 13 downstream from the egress orifice thereof.
  • the channel 9 should be as close to the passages 2 and 3 as possible so as to maximize the amount of fluid having maximum pressure entering channel 9.
  • the factor of maximum pressure is not the only controlling factor in the system. If the point of interaction between the streams issued by the passages 2 and 3 is too close to the passages, then the static pressure buildup due to interaction of the streams feeds back into the passages and alters the input signal impedance so as to adversely affect the input signal pressure and flow conditions.
  • the point of interaction of these two streams should be downstream of the egress orifice by at least two widths of the egress orifice of the input passages for best operation.
  • the static pressure build-up may be dissipated through the space between the bottom wall 11 and the top plate 12 and the pressure-flow conditions in the passages 2 and 3 remain adequately decoupled.
  • the outlet passage 9 is sufliciently small to monitor only a very narrow region along the centerline of the device, then it is possible to go as far downstream as six widths of the nozzles 2 and 3 and produce an output pressure closely related to the maximum pressure in one or the other of the passages 2 or 3.
  • a desirable range for operation is to locate the egress orifice of the channel 9 at a distance downstream from the egress orifices of the passages 2 and 3 equal to two to four times the egress orifice width. So long as this constraint is observed, it is found that very excellent results can be obtained; that is, the output pressure substantially follows the maximum pressure applied to the system.
  • the other constraint on the system is that the inlet to the passage 9 be small compared to the egress orifice of the supply passages. More particularly, the width of the ingress orifice of the passage 9 should be no greater than one-half of the width of the egress orifices of the passages 2 and 3.
  • the ingress orifice of the passage 9 is preferably located at the point of intersection of the centerlines of the passages 2 and 3 or one ingress orifice width upstream or downstream of this point. The effect of this variable is illustrated in FIGURE 3 of the accompanying drawings.
  • nozzles 16 and 17 issue two streams of fluid whose centerlines intersect at apoint 18.
  • the adjacent or inner peripheries or sides of the streams issues by nozzles 16 and 17 intersect at a point 19.
  • a line 21 represents the ingress orifice to the receiver passage located at the intersecting point 18 with the ingress passage having a width equal to one-half of the width of the egress orifices of the passages 16 and 17.
  • the ingress orifice 21 of the receiver passage is located four nozzle widths downstream of the egress orifices.
  • a line 21a indicates the location of the ingress orifice of the outlet passage when located one orifice width upstream of the point 18 of intersection of the centerlines of the streams.
  • a line 2121 represents the position of the ingress orifice of the outlet passage when it is located one orifice width downstream of the point of intersection 18 of the centerlines of the streams.
  • FIGURE 3 seems to indicate that the orifice, for instance 21, straddles regions part of which are of the maximum pressure and part of which are at the reduced pressures due to entrainment.
  • the regions of maximum pressure do not remain symmetrical with respect to the streams but move towards each other; that is, move towards the barrier which each stream presents to the other stream.
  • FIGURES 4a and 4b This phenomenon is explained with respect to FIGURES 4a and 4b.
  • the stream patterns are drawn as if the streams do not intersect.
  • the point of intersection of the centerlines is designated by the reference numeral 22, and the ingress orifice of an outlet passage is designated by the numeral 23.
  • the adjacent regions of the streams which are below maximum pressure are designated by reference numeral and the maximum width of the combined lower velocity regions is designated by line 25.
  • the line 25 is almost as long as the line 22 which seems to indicate that the majority of the fluid that would enter the outlet orifice would be fluid having a pressure below maximum pressure. This is based upon the reasoning that when the two streams intersect, being equal, all flow lines are turned to flow vertically upward as viewed in FIGURE 4a. However, this is not the case and the flow patterns alter materially when the streams intersect.
  • FIGURE 4b represents the actual conditions when two streams intersect.
  • FIGURE 41 it will be noted that, as the streams converge, the maximum pressure region of each stream in effect moves towards the center of the configuration. The lower velocity fluid which exists between these two maximum pressure regions is compressed and becomes a smaller portion of the total stream than these regions of fluid represented immediately prior to confluence of the two streams. Also, due to the entrainrnent effect resulting from momentum of the intersecting streams, the velocity and associated total pressure in the lower pressure region 20 are raised very close to the maximum velocity and associated total pressure of the streams.
  • the pressure at the ingress orifice 22 to the outlet tube is a minimum of ninety-five percent of the maximum pressure of the fluid streams.
  • systems can be designed which provide an output pressure of 98-99 percent of the maximum input pressure to the system.
  • the maximum pressure regions of the streams tend to move toward one another when the streams intersect and in so doing compress and reaccelerate the lower total pressure fluid between the two higher pressure regions and raise the total pressure of the lower pressure region towards the higher total pressure level. This is readily seen in FIGURE 4b.
  • the maximum effect of the lower total pressure fluid entering the receiving aperture is to reduce by five percent the total pressure indicated and is usually considerably less.
  • the location of the ingress orifice to the outlet passage, relative to the point of intersection of the centerlines of the streams, has an effect upon the total pressure region captured.
  • these relationships are not quite as clear as might be thought by observing FIGURE 3. It would appear that the best location of the ingress orifice is as indicated by reference numeral 211), since it takes a smaller deflection of the lefthand stream to exclude it from the egress orifice. On the other hand, the lefthand stream has a longer distance in which to act to deflect the main stream so that some of these effects cancel one another.
  • the best location of the ingress orifice in a given system depends upon other factors such as the pressure ranges over which the streams are variable, the Reynolds numbers of the fluids and other conditions of the fluid rather than of the structure.
  • the ingress orifice is smaller than the egress orifices of the passages 16 and 17 so that the output passage sees the maximum pressures of the streams rather than an average including the adjacent and non-adjacent minimum and maximum pressure regions.
  • a size of the ingress orifice equal to the one-half size of the egress orifice of passages 16 and 17 has been found to give very good results.
  • a full wave fluid rectifier In the apparatus of FIGURE 5, there is provided a full wave fluid rectifier.
  • the rectifier includes an analog amplifier generally designated by the reference numeral 26 having a main power nozzle 27 and control or input nozzles 28 and 29 disposed on opposite sides of the device and oppositely directed relative to one another.
  • the device also has two output passages 31 and 32.
  • the right control passage 29 may be connected to a source of bias pressure P+ while the lefthand control nozzle 28 may be connected to a variable pressure source which varies the pressure of the system about the pressure P+ applied to the righthand nozzle 29.
  • the variable pressure applied to the control nozzle 28 is, for purposes of explanation, taken to be a sinusoidal variable.
  • the outer passages 31 and 32 constitute the input passages to the maximum pressure selector to the present invention, the selector being designated by reference numeral 33 in FIGURE 5 and its output passage being designated by the reference numeral 34.
  • the variations in pressure in the input passage 32 to the pressure selector 33 are illustrated above the passage 34 and constitute half sine waves designated by numerals 36 and 37.
  • the pressure variation in the output passage 31 is designated by the reference numeral 38.
  • the pressure in the output passage 34 follows the outline indicated by the darkened portion of the wave and thus the input signal applied to the control passage 28 is rectified to provide a pulsating unidirectional signal relative to the bias pressure.
  • the apparatus of the present invention is not restricted to two input channels and a three or more input channel device may be employed as illustrated in FIGURE 6 of the accompanying drawings.
  • the operation of this device is essentially the same as the operation of the device of FIGURE 1.
  • the essential feature of the system is that the ingress orifice 39 of an output passage 41 be sufficiently narrow relative to stream core widths and sufficiently close to the egress orifices 42, 43 and 44 of supply passages 46, 47 and 48, respectively, that the momentum of the various streams cannot average over both core and low velocity regions of the combined stream.
  • a pure fluid maximum pressure selector for providing a fluid output signal having a pressure which is always substantially equal to the highest pressure of a plurality of input pressure signals comprising:
  • At least first and second input passages having egress means for connecting said input passages to receive respective ones of said input pressure signals
  • an output passage for conducting said fluid output signal located downstream of said input passages and having an ingress orifice;
  • said ingress orifice of said output passage being located downstream of said egress orifices of said input passages by a distance of between two and six times the width of said egress orifices;
  • the region between said input and output passages having sufficient volume to maintain ambient pressure in said region.
  • a pure fluid maximum pressure selector for providing a fluid output signal having a pressure which is always substantially equal to the highest pressure of a plurality of input pressure signals comprising:
  • At least first and second input passages having egress means for connecting said input passages to receive respective ones of said input pressure signals
  • an output passage for conducting said fluid output signal located downstream of said input passages and having an ingress orifice;
  • said ingress orifice of said output passage being located downstream of said egress orifices of said input passages by a distance of between two and six times the width of said egress orifices;
  • a pure fluid maximum pressure selector for providing a fluid output signal having a pressure which is always substantially equal to the highest pressure of a plurality of input pressure signals comprising:
  • At least first and second input passages having egress orifices; means for connecting said input passages to receive respective ones of said input pressure signals; an output passage for conducting said fluid output signal located downstream of said input passages and having an ingress orifice; said ingress orifice of said output passage being located downstream of said egress orifices of said input passages by a distance of between two and four times the width of said egress orifices; the angular relationship between said input passages being such that their centerlines intersect in the region of said ingress orifice of said output passage; and the region between said input and output passages having sufiicient volume to maintain ambient pressure in said region.
  • a pure fluid maximum pressure selector for providing a fiuid output signal having a pressure which is always substantially equal to the highest pressure of a plurality of input pressure signals comprising:
  • At least first and second input passages having egress means for connecting said input passages to receive respective ones of said input pressure signals
  • an output passage for conducting said fluid output signal located downstream of said input passages and having an ingress orifice;
  • said ingress orifice of said output passage being located downstream of said egress orifices of said input passages by a distance of between two and four times the width of said egress orifices; the angular relationship between said input passages being such that their centerlines intersect in the region of said ingrees orifice of said output passage;
  • the width of said ingress orifice of said output passage being at the most approximately one-half the width of each of said egress orifices of said input passages.
  • said third input passage being coaxial with said output passage.
  • said system comprises a rectifier device including means for introducing difierentially fluctuating signals into said first and second input passages.
  • a pure fluid rectifier comprising:
  • a fluid amplifier including a power nozzle, means for developing a fluctuating pressure gradient across a power stream issued by said power nozzle and a pair of output passages;
  • a pure fluid maximum pressure selector for providing a fluid output signal having a pressure which is always substantially equal to the highest pressure of a pair of input pressure signals including at least a pair of input passages having egress orifices, and an output passage for conducting said fluid output signal located downstream of said input passages and having an ingress orifice, said ingress orifice of said output passage being located downstream of said egress orifices of said input passages by a distance of between two and six times the width of said egress orifices, the angular relationship between said input passages being such that their centerlines intersect in the region of said ingrees orifice of said output passage, and the region between said input and output passages having sufficient volume to maintain ambient pressure in said region; and
  • the width of said ingresss orifice of said output passage is at the most approximately one-half the width of each of said egress orifices of said input passages.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Nozzles (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
  • Measuring Volume Flow (AREA)
US386492A 1964-07-31 1964-07-31 Maximum pressure selector Expired - Lifetime US3411520A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US386492A US3411520A (en) 1964-07-31 1964-07-31 Maximum pressure selector
GB28227/65A GB1117470A (en) 1964-07-31 1965-07-02 Maximum pressure selector
DE19651523458 DE1523458B2 (de) 1964-07-31 1965-07-24 Strömungsmittelkomparator
DE19651774975 DE1774975B2 (de) 1964-07-31 1965-07-24 Stroemungsmittelsignalsteuervorrichtung

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GB (1) GB1117470A (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3500847A (en) * 1967-02-28 1970-03-17 Gen Electric Variable gain fluidic device
US3503423A (en) * 1968-04-10 1970-03-31 Bowles Eng Corp Fluidic signal selector
US3516428A (en) * 1966-09-21 1970-06-23 Gen Electric Fluidic rectifier device
US3552414A (en) * 1968-01-24 1971-01-05 Garrett Corp Pulsating fluid pressure frequency rectifier
US3687147A (en) * 1970-08-05 1972-08-29 Bowles Fluidics Corp Jet velocity augmentation apparatus
US3738391A (en) * 1970-10-30 1973-06-12 Moore Prod Co Fluid pressure comparator

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3122165A (en) * 1960-09-19 1964-02-25 Billy M Horton Fluid-operated system
US3128040A (en) * 1962-10-29 1964-04-07 Ibm Fluid logic device
US3191612A (en) * 1962-08-01 1965-06-29 Sperry Rand Corp Jet pipe pneumatic or gate
US3212515A (en) * 1962-07-13 1965-10-19 Giannini Controls Corp Fluid amplifier
US3238961A (en) * 1963-10-10 1966-03-08 Foxboro Co Fluid switch
US3266509A (en) * 1963-08-26 1966-08-16 Sperry Rand Corp Fluid pulse former
US3282281A (en) * 1963-12-23 1966-11-01 Sperry Rand Corp Fluid or gate

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3122165A (en) * 1960-09-19 1964-02-25 Billy M Horton Fluid-operated system
US3212515A (en) * 1962-07-13 1965-10-19 Giannini Controls Corp Fluid amplifier
US3191612A (en) * 1962-08-01 1965-06-29 Sperry Rand Corp Jet pipe pneumatic or gate
US3128040A (en) * 1962-10-29 1964-04-07 Ibm Fluid logic device
US3266509A (en) * 1963-08-26 1966-08-16 Sperry Rand Corp Fluid pulse former
US3238961A (en) * 1963-10-10 1966-03-08 Foxboro Co Fluid switch
US3282281A (en) * 1963-12-23 1966-11-01 Sperry Rand Corp Fluid or gate

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3516428A (en) * 1966-09-21 1970-06-23 Gen Electric Fluidic rectifier device
US3500847A (en) * 1967-02-28 1970-03-17 Gen Electric Variable gain fluidic device
US3552414A (en) * 1968-01-24 1971-01-05 Garrett Corp Pulsating fluid pressure frequency rectifier
US3503423A (en) * 1968-04-10 1970-03-31 Bowles Eng Corp Fluidic signal selector
US3687147A (en) * 1970-08-05 1972-08-29 Bowles Fluidics Corp Jet velocity augmentation apparatus
US3738391A (en) * 1970-10-30 1973-06-12 Moore Prod Co Fluid pressure comparator

Also Published As

Publication number Publication date
DE1774975B2 (de) 1973-09-06
DE1523458B2 (de) 1972-11-02
GB1117470A (en) 1968-06-19
DE1774975A1 (de) 1973-05-03
DE1523458A1 (de) 1969-08-21

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