US3511268A - Apparatus for varying the cross-sectional area of the throat of a venturi tube - Google Patents

Apparatus for varying the cross-sectional area of the throat of a venturi tube Download PDF

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Publication number
US3511268A
US3511268A US743510A US3511268DA US3511268A US 3511268 A US3511268 A US 3511268A US 743510 A US743510 A US 743510A US 3511268D A US3511268D A US 3511268DA US 3511268 A US3511268 A US 3511268A
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US
United States
Prior art keywords
pressure
throat
venturi tube
intake
pressure differential
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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
Application number
US743510A
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English (en)
Inventor
Ricardo S Dubrovsky
James P Tomany
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Universal Oil Products Co
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Universal Oil Products Co
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Publication date
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Publication of US3511268A publication Critical patent/US3511268A/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
    • G01F1/34—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure
    • G01F1/36—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure the pressure or differential pressure being created by the use of flow constriction
    • G01F1/37—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure the pressure or differential pressure being created by the use of flow constriction the pressure or differential pressure being measured by means of communicating tubes or reservoirs with movable fluid levels, e.g. by U-tubes
    • G01F1/372—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure the pressure or differential pressure being created by the use of flow constriction the pressure or differential pressure being measured by means of communicating tubes or reservoirs with movable fluid levels, e.g. by U-tubes with electrical or electro-mechanical indication
    • 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
    • Y10T137/7722—Line condition change responsive valves
    • Y10T137/7758—Pilot or servo controlled
    • Y10T137/7759—Responsive to change in rate of fluid flow
    • Y10T137/776—Control by pressures across flow line valve

Definitions

  • This method and apparatus for varying the cross-sectional area of the throat of a venturi tube involves at least partially evacuating the space enclosed between a flexible throat of a venturi tube and a rigid shell encompassing the throat and forming an airtight seal with the venturi tube. Evacuation is effected to the degree necessary to maintain a constant pressure differential between the intake and exhaust of the venturi tube at varying process gas flow.
  • This method and apparatus for varying the cross-sectional area of the throat of a venturi tube involves evacuating the space enclosed between a flexible throat of a venturi tube and a rigid shell encompassing the throat and forming an airtight seal with the venturi tube. More particularly, evacuation is effected to reduce to the necessary extent the pressure in the space enclosed by the shell and the venturi tube to prevent the central portion of the flexible throat from being drawn radially inward by a gas stream, under negative pressure, passing through the venturi tube.
  • Another device which has been used to vary the crosssectional area of a flexible venturi throat is an inflatable material lining the inside of the venturi throat.
  • the material lining the throat is inflated, thus decreasing the eflective crosssectional area of the throat, thereby maintaining the pressure differential desired across the venturi tube.
  • This arrangement is disadvantageous in that while it functions properly when used with all incompressible fluids, it will not accomplish its purpose when a compressible gas passes through the venturi tube and when the pressure of the ice compressible gas stream at the venturi throat is less than the ambient pressure surrounding the throat.
  • the ambient pressure unrestrained will force the walls of the throat radially inward when the pressure inside the throat is less than surrounding ambient pressure. If this is allowed to happen, the rate of flow and the intake pressure will determine the cross-sectional area of the throat, and consequently the pressure ditferential between the intake and the exhaust of the venturi tube.
  • the control that is required to maintain the proper pressure differential across the venturi tube is not a means for forcing the walls of the venturi throat inward to form a smaller crosssection, as has been attempted, but rather a means for forcing the walls of a venturi throat outward to form a larger cross-sectional area. This is accomplished using the present invention.
  • this invention provides in combination with a venturi tube having an intake, a throat, and an exhaust, the improvement comprising a flexible throat exhaust having an inlet end sealed airtight to the intake of the venturi tube, having an outlet end sealed airtight to the exhaust of the venturi tube, and having a flexible, radially movable central portion, a rigid shell encompassing said throat and forming an airtight intersection with said venturi tube at both ends of said throat; a vacuum source; a valving means connected to said vacuum source and positionable to allow air to be drawn to said vacuum source to a varying extent from the space bounded by said shell and said venturi tube; a connector tube connecting said valving means to the space bounded by said shell and said venturi tube; a pressure differential measuring device connected both to the intake and the exhaust of said venturi tube; and a pressure differential transmitter connected to said pressure differential measuring device and to said valving means, whereby said pressure differential transmitter positions said valving means in response to pressure differential changes in order to maintain a
  • this invention is a method of varying cross-sectional area of a flexible venturi tube throat having a flexible radially movable central portion, said throat being encompassed by a rigid shell which forms an airtight intersection with the venturi tube at both ends of said throat, comprising the steps of: measuring pressure diflferential of a compressible gas stream across the venturi tube; and evacuating the space enclosed between said venturi tube and said rigid shell in response to and in proportion to changes in pressure differential across said venturi tube.
  • the variation in cross-sectional area of the venturi tube in response to pressure differential variations across the venturi tube acts to maintain a desired pressure differential at varying process gas flow rates.
  • the principles of fluid dynamics can be used to show that in a gas flow through a venturi tube, the pressure varies inversely with the velocity.
  • the pressure of a compressible gas stream of the venturi tube at the throat will always be less than the pressure at the intake.
  • the pressure at the throat will often fall below atmospheric pressure.
  • the physical construction and operation of the valving means and the pressure differential transmitter of this invention may take a variety of forms. Either of these arrangements may be operated in a number of ways including, but not limited to electric, spring biased, and pneumatic operation, or any combination thereof. Any compatible constructions of these devices may be used with each other.
  • the preferred embodiments of this invention utilize either a pressure differential transmitter which emits an electrical signal to position the valving means, or a pressure differential transmitter which emits a pneumatic signal to position the valving means.
  • the venturi tube normally is constructed symmetrical about a linear axis.
  • the shape of the venturi tube may be modified for some applications, and the axis about which the component parts of the venturi tube are mounted may have a curvature of a more unconventional nature.
  • venturi tube 23 is comprised of intake 2, a flexible rubber throat 1, and exhaust 3. While throat 1 as illustrated is constructed of rubber, it may be constructed of any organic elastic material. Intake 2, throat 1, and exhaust 3 are shown arranged on a common axis. Flexible throat I has its inlet end 32 sealed airtight around the entire perimeter of the juncture with the adjacent portion of intake section 2 of venturi tube 23, while an outlet end 34 is sealed airtight around the entire perimeter of the adjacent portion of exhaust section 3 of venturi tube 23. The central portion 33 of the throat section shall be readily flexible and radially movable with respect to said axis of the entire unit.
  • the pressure at point a a point in the intake section 2 is transmitted through a connector leg 24 to a manometer 5.
  • a point in the exhaust section 3 pressure is transmitted through a connector leg 25 to a manometer 5.
  • Point b is designated as being within the narrowest portion of flexible throat I.
  • a shell 4 constructed of steel or other material more rigid than throat 1, is shown encompassing throat 1 and forming an airtight intersection with the venturi tube 23 at both ends of throat I. That is, shell 4 circumferentially intersects and becomes sealed with intake section 2 and exhaust section 3.
  • a connector tube 9 connects the zone within shell 4 to valving means 11.
  • Valving means 11 is, in turn, connected to a vacuum source (not shown) by line 12.
  • Valving means 11 is positionable to allow air to be drawn to said vacuum source alternatively and to varying degrees through connector tube 9 from the space bounded by shell 4 and venturi tube 23, and from the atmosphere through line 10.
  • valving means 11 is comprised of an enclosing retainer wall 27 in which there is an air passage to line 12.
  • Valving means 11 is further comprised of an elongated inflatable tube or bag 14, crimped to and attached to air passage block 13, a spring means 16 which tends to pull air passage block 13 away from line 10, and a connection line 15 connected to an inflatable bag 14 and leading to a pressure differential transmitter 17.
  • connection line 15 When air pressure is transmitted from pressure differential transmitter 17 through connection line 15, bag 14 is inflated and tends to straighten out in its direction of elongation, from its ciimped position against air passage block 13, thereby forcing air passage block 13 to pivot about pivot means 26 away from connection tube 9 and in front of line 10.
  • inflated bag 14 loses air pressure back through connection line 15, and bag 14 resumes its uninflated position against block 13, as spring 16 pivots block 13 about pivot means 26 to draw block 13 away from line 10.
  • Pressure differential transmitter 17 emits a pneumatic signal through tube 15 to position valving means 11.
  • Pressure differential transmitter 17 is operated independently by a compressed air supply (not shown), and is comprised of a rigid, enclosing wall 30 with an opening to connection line 15 and with an air pressure relief valve 29.
  • An air supply tube 22, connected to the compressed air supply, enters through an opening in wall 30 and forms an airtight seal with wall 30, as does connection line 15.
  • a portion of the air supply tube 22 extends into pressure differential transmitter 17, and in this portion of tube 22 is positioned an electromagnetic relay means 18, which, when operated, draws spring steel bar 19 to it.
  • Spring steel bar 19 is rigidly fastened to air supply tube 22 at weld 28.
  • Electromagnetic relay 18 is strong enough to overcome pressure from the compressed air supplied through tube 22, and to thereby pull spring steel bar 19 upward when operated by an electric current supplied by a battery through insulated electric wires 7 and 8 Which enter and are sealed to wall 30 and air supply tube 22.
  • electromagnetic relay 18 When electromagnetic relay 18 is operated, spring steel bar 19 is drawn upward, needle valve 20 is unseated from valve seat 21, and compressed air is allowed to enter the space enclosed by wall 30 and is thereby transmitted to connection line 15 to operate valving means 11.
  • spring steel bar 19 returns to its normal position, thus seating needle valve 20 in valve seat 21, thereby precluding further pressure from being transmitted to valve 11.
  • connection line 15 is relieved through pressure relief valve 29 which allows air to slowly escape to the atmosphere, when needle valve 20 is seated, through pressure relief valve 29.
  • Pressure relief valve 29 is of insufficient size to materially affect the pressure being transmitted to connection line 15 when needle valve 20 is unseated.
  • Electromagnetic relay 18 is operated by a battery when contacts d and e are closed in a leg of manometer connected to connector leg 25. Contacts at and e are closed when the pressure differential between intake section 2 and exhaust section 3 of venturi tube 23 rises sufficiently to allow the mercury 6 in manometer 5 to rise to the level of contacts d and e in the leg connected to connector leg 25.
  • the leg leading to connector leg 25 has a number of paired copper wires extending through its wall at various levels. Contact a, which is connected to wire 31, is attached to one of the pair of copper wires at the level desired.
  • Pressure differential transmitter 17 is connected to the pressure differential measuring device, manometer 5, by a connection means comprising contacts d and e, and wires 7, 8, and 31.
  • the vacuum connected to valving means 11 draws air from the space encompassed by rigid shell 4, thereby equalizing pressure between that space and the pressure in the valve throat at b. With the pressure equalized, there is no longer a tendency for flexible throat 1 to contract.
  • the space encompassed by rigid shell 4 is sufficiently evacuated, the pressure drop from a to 0 will again reach the desired level and the electric contact through mercury 6 will be broken. When this occurs, the result in the apparatus depicted is the same as when pressure at point a decreases.
  • the present invention can be further illustrated by the following example.
  • the nominal cross-sectional area of the throat is one quarter that of both the intake and the exhaust, air passes through the venturi tube at a velocity of approximately 200 feet per second, the density of this air being .090 pound per cubic foot.
  • the pressure drop between the intake and exhaust of the venturi tube is about 15 inches of water, and the throat pressure is less than the ambient atmospheric pressure.
  • a flexible throat having an inlet end sealed airtight to the intake of the venturi tube, having an outlet end sealed airtight to the exhaust of the venturi tube, and having a flexible radially movable central portion;
  • a valving means connected to said vacuum source and positionable to allow air to be drawn to said vacuum source to a varying extent from the space bounded by said shell and said venturi tube;
  • a pressure differential transmitter connected to said pressure differential measuring device and to said valving means, whereby said pressure difierential transmitter positions said valving means in response to pressure diiferential changes in order to maintain a pre-determined pressure ditferential between the intake and exhaust of the venturi tube;
  • connection means connecting said pressure differential transmitter to said pressure differential measuring device.
  • the apparatus of claim 1 further characterized in that said valving means is positionable to allow air to be drawn to said vacuum source alternatively and to varying degrees from said space bounded by said shell and said venturi tube and from the atmosphere.

Landscapes

  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Fluid Pressure (AREA)
  • Sampling And Sample Adjustment (AREA)
  • Separation Of Particles Using Liquids (AREA)
  • Control Of Fluid Pressure (AREA)
US743510A 1968-07-09 1968-07-09 Apparatus for varying the cross-sectional area of the throat of a venturi tube Expired - Lifetime US3511268A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US74351068A 1968-07-09 1968-07-09

Publications (1)

Publication Number Publication Date
US3511268A true US3511268A (en) 1970-05-12

Family

ID=24989059

Family Applications (1)

Application Number Title Priority Date Filing Date
US743510A Expired - Lifetime US3511268A (en) 1968-07-09 1968-07-09 Apparatus for varying the cross-sectional area of the throat of a venturi tube

Country Status (6)

Country Link
US (1) US3511268A (zh)
JP (1) JPS5022195B1 (zh)
CA (1) CA921360A (zh)
FR (1) FR2012591A1 (zh)
GB (1) GB1265693A (zh)
SE (1) SE367261B (zh)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4442954A (en) * 1982-07-30 1984-04-17 National Instrument Company, Inc. Self-pressurizing pinch valve
US20140261421A1 (en) * 2013-03-15 2014-09-18 Apex Medical Corp. Gas flow detector and positive airway pressure apparatus containing the same
US20150209818A1 (en) * 2014-01-26 2015-07-30 Tokyo Electron Limited Inline Dispense Capacitor
TWI594731B (zh) * 2013-03-15 2017-08-11 雃博股份有限公司 氣體流量偵測裝置及包含其之陽壓呼吸器
CN109738032A (zh) * 2019-03-14 2019-05-10 湖南大麓科技有限公司 一种管道流量测定装置和方法
US11084745B1 (en) 2021-02-17 2021-08-10 Aquastar Pool Products, Inc. Ozone injector device
US11358888B1 (en) 2021-02-17 2022-06-14 Aquastar Pool Products, Inc. Ozone injector device
USD972069S1 (en) 2021-02-17 2022-12-06 Aquastar Pool Products, Inc. Ozone injector device
US11905191B1 (en) 2021-02-17 2024-02-20 Aquastar Pool Products, Inc. Ozone injector device

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1934713A (en) * 1931-04-10 1933-11-14 Gen Zeolite Co Fluid flow controller
US1969366A (en) * 1934-08-07 Fluid flow controller
US1981576A (en) * 1928-05-25 1934-11-20 Pittsburgh Equitable Meter Co Fluid pressure regulator
US2467150A (en) * 1943-11-12 1949-04-12 Carl H Nordell Valve
US2877791A (en) * 1955-08-15 1959-03-17 Fisher Governor Co Flexible diaphragm flow control valve
US3441245A (en) * 1966-03-25 1969-04-29 Galigher Co Fluid-actuated,anti-flutter,pinch-sleeve,throttling valve

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1969366A (en) * 1934-08-07 Fluid flow controller
US1981576A (en) * 1928-05-25 1934-11-20 Pittsburgh Equitable Meter Co Fluid pressure regulator
US1934713A (en) * 1931-04-10 1933-11-14 Gen Zeolite Co Fluid flow controller
US2467150A (en) * 1943-11-12 1949-04-12 Carl H Nordell Valve
US2877791A (en) * 1955-08-15 1959-03-17 Fisher Governor Co Flexible diaphragm flow control valve
US3441245A (en) * 1966-03-25 1969-04-29 Galigher Co Fluid-actuated,anti-flutter,pinch-sleeve,throttling valve

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4442954A (en) * 1982-07-30 1984-04-17 National Instrument Company, Inc. Self-pressurizing pinch valve
US20140261421A1 (en) * 2013-03-15 2014-09-18 Apex Medical Corp. Gas flow detector and positive airway pressure apparatus containing the same
TWI594731B (zh) * 2013-03-15 2017-08-11 雃博股份有限公司 氣體流量偵測裝置及包含其之陽壓呼吸器
US20150209818A1 (en) * 2014-01-26 2015-07-30 Tokyo Electron Limited Inline Dispense Capacitor
US9718082B2 (en) * 2014-01-26 2017-08-01 Tokyo Electron Limited Inline dispense capacitor
CN109738032A (zh) * 2019-03-14 2019-05-10 湖南大麓科技有限公司 一种管道流量测定装置和方法
US11345623B1 (en) 2021-02-17 2022-05-31 Aquastar Pool Products, Inc. Ozone injector device
US11235996B1 (en) 2021-02-17 2022-02-01 Aquastar Pool Products, Inc. Ozone injector device
US11084745B1 (en) 2021-02-17 2021-08-10 Aquastar Pool Products, Inc. Ozone injector device
US11358888B1 (en) 2021-02-17 2022-06-14 Aquastar Pool Products, Inc. Ozone injector device
US11518697B1 (en) 2021-02-17 2022-12-06 Aquastar Pool Products, Inc. Ozone injector device
USD972069S1 (en) 2021-02-17 2022-12-06 Aquastar Pool Products, Inc. Ozone injector device
USD992080S1 (en) 2021-02-17 2023-07-11 Aquastar Pool Products, Inc. Ozone injector device
USD993355S1 (en) 2021-02-17 2023-07-25 Aquastar Pool Products, Inc. Ozone injector device
USD997296S1 (en) 2021-02-17 2023-08-29 Aquastar Pool Products, Inc. Ozone injector device
US11820683B1 (en) 2021-02-17 2023-11-21 Aquastar Pool Products, Inc. Ozone injector device
US11905191B1 (en) 2021-02-17 2024-02-20 Aquastar Pool Products, Inc. Ozone injector device

Also Published As

Publication number Publication date
DE1933945A1 (de) 1970-01-22
CA921360A (en) 1973-02-20
DE1933945B2 (de) 1972-09-21
FR2012591A1 (zh) 1970-03-20
GB1265693A (zh) 1972-03-01
SE367261B (zh) 1974-05-20
JPS5022195B1 (zh) 1975-07-29

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