SE506368C2 - Device for differential pressure measurement as well as use of the device for density measurement - Google Patents

Device for differential pressure measurement as well as use of the device for density measurement

Info

Publication number
SE506368C2
SE506368C2 SE9601581A SE9601581A SE506368C2 SE 506368 C2 SE506368 C2 SE 506368C2 SE 9601581 A SE9601581 A SE 9601581A SE 9601581 A SE9601581 A SE 9601581A SE 506368 C2 SE506368 C2 SE 506368C2
Authority
SE
Sweden
Prior art keywords
pressure
probe
sensors
differential pressure
servomedium
Prior art date
Application number
SE9601581A
Other languages
Swedish (sv)
Other versions
SE9601581L (en
SE9601581D0 (en
Inventor
Hans Persson
Original Assignee
Hans Persson
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 Hans Persson filed Critical Hans Persson
Priority to SE9601581A priority Critical patent/SE506368C2/en
Publication of SE9601581D0 publication Critical patent/SE9601581D0/en
Priority to AU27204/97A priority patent/AU2720497A/en
Priority to EP97921056A priority patent/EP0895582A1/en
Priority to PCT/SE1997/000690 priority patent/WO1997040350A1/en
Publication of SE9601581L publication Critical patent/SE9601581L/en
Publication of SE506368C2 publication Critical patent/SE506368C2/en

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/14—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measurement of pressure
    • G01F23/16—Indicating, recording, or alarm devices being actuated by mechanical or fluid means, e.g. using gas, mercury, or a diaphragm as transmitting element, or by a column of liquid
    • G01F23/164—Indicating, recording, or alarm devices being actuated by mechanical or fluid means, e.g. using gas, mercury, or a diaphragm as transmitting element, or by a column of liquid using a diaphragm, bellow as transmitting element
    • 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
    • G01F1/38—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 a movable element, e.g. diaphragm, piston, Bourdon tube or flexible capsule
    • G01F1/383—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 a movable element, e.g. diaphragm, piston, Bourdon tube or flexible capsule with electrical or electro-mechanical indication
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L11/00—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
    • G01L11/004—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by the use of counterbalancing forces
    • G01L11/006—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by the use of counterbalancing forces hydraulic or pneumatic counterbalancing forces
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N9/00—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
    • G01N9/26—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity by measuring pressure differences

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Measuring Fluid Pressure (AREA)

Abstract

There is described a device that is useful in determining pressure gradients in liquids, for instance. Pressure sensing is effected with the aid of two sensors (7, 8) mounted at a predetermined distance apart, wherein the membranes (9, 10) of respective sensors are in connection with a servomedium. The device includes separate servomedium pressure regulators (11, 12) which balance out each of the membranes to equilibrium with liquid outside the sensors in response to control signals (3, 4) delivered by conventional detectors in the sensors. The servomedium in respective sensors is connected to a common differential pressure measuring device (13). The structurally simple measuring system is particularly suitable for determining the intensity of liquids under difficult conditions, for instance in systems having varying liquid levels, in corrosive environments, in cases when the liquids are heavily contaminated, under fluctuating pressures and temperatures, and so on.

Description

10 15 20 25 30 506 568 2 rör med två tryckavkänningssonder. Vardera sonden matas med ett tryckreglerat fluidum samt är försedd med ett inlopp och två utlopp för fluidet. Sondens utflöden är likaså tryck- reglerade. Det ena utloppet regleras därutöver av en klaff, vilken står i förbindelse med sondens tryckavkännande membran. Det andra utloppet undergår tryckreduktion efter passage av ett hålrum i sonden. De tryckavkännande rörelserna via membranet blir därigenom ytterligt små. Det anges på sidan 8 i utläggningsskriften att sonderna kan användas vid t ex avkänning av tryck och nivåer i t ex reservoarer. Till skillnad mot anordningen enligt uppfmningsföremålet upprätthålles dock enligt hänvisningen ett konstant tryck inom respektive sond vilket utesluter användning av mätdon med differens- tryckgivare. 10 15 20 25 30 506 568 2 tube with two pressure sensing probes. Each probe is fed with a pressure-regulated fl uidum and is provided with one inlet and two outlets for fl uidet. The fate of the probe is also regulated. One outlet is additionally regulated by a flap, which is connected to the probe's pressure sensing diaphragm. The second outlet undergoes pressure reduction after passage of a cavity in the probe. The pressure sensing movements via the diaphragm become thereby extremely small. It is stated on page 8 of the explanatory memorandum that the probes can be used for, for example, sensing pressure and levels in, for example, reservoirs. Unlike however, the device according to the object of the invention is maintained according to the reference one constant pressure within each probe, which excludes the use of measuring devices with different pressure transmitter.

De sonder som användes i det föreliggande mätsystemet är under mätförloppet utbalanserade genom ett servomedium i separata reglerkretsar, och till skillnad mot tidigare teknik möjliggöres efter reglering till järnvikt mellan yttre och inre tryck hos respektive sondmembran registrering via ett rnätdon av en tryckdifferens mellan två mätpunkter. Membranens deflexion d v s i normalfallet initial inåtbuktning styres på basis av induktans från ett givarelement i sonden men också andra givarmöjligheter som piezoelektricitet och tràdtöjningsrelaterad resistivitet är användbara. Företrädesvis genom- föres styrning till noll-deflexion, även om andra deflexionsgrader är möjliga vid ut- balansering. Som servomedium vid utbalanseringen kan användas inerta gaser eller låg- viskösa vätskor, som ej är elektriskt ledande.The probes used in the present measuring system are during the measuring process balanced by a servo medium in separate control circuits, and unlike prior art is made possible after regulation to iron weight between external and internal pressures of respective probe diaphragm registration via a network device of a pressure difference between two measuring points. The deflection of the membrane, i.e. normally initial inward curvature, is controlled on a basis of inductance from a sensor element in the probe but also other sensor possibilities such as piezoelectricity and wire strain-related resistivity are useful. Preferably, control is brought to zero-de fl exion, although other de fl degrees of excision are possible at balancing. Inertial gases or low inertia can be used as servo medium for balancing. viscous liquids, which are not electrically conductive.

Stumma membrantyper med liten area är att föredra, eftersom membranen är förhållandevis okänsliga mot påbyggnad av främmande material, som förändrar givarele- mentens massa. Vid denna membrantyp elimineras även krypningsfenomen i materialet.Dumb membrane types with a small area are preferable, because the membranes are relatively insensitive to the build-up of foreign matter, which alters the donor ment mass. With this type of membrane, creep phenomena in the material are also eliminated.

I figur 1 återges schematiskt föreliggande mätsystem, varigenom funktions- principema framgår i stora drag. Varje mätsond (7,8) är fast monterad vid ett fixt avstånd mellan de bägge mätpunkterna. Det förutsättes att en tryckskillnad föreligger vid detta konstanta avstånd. Genom separata tiyckregulatorer (ll,12) utbalanseras respektive sond- membran (9,10) med hjälp av exempelvis en hydraulventil i regulatom och därvid registreras genom ett mätdon (13) tryckskillnaden dP mellan servomedierna i respektive krets. ' Tryckregulatorema matas i princip av ett trycksatt servomedium från gemensam anslutning (1). Mottrycket i vardera sonden svarar vid utbalanseringen, d v s efter upp- nådd jämvikt mellan trycket i servomediet (2) och trycket på givarens utsida, mot det 10 15 506 368 3 rådande trycket på membranets utsida. Genom att ansluta mätdonet för differenstryck (13) till servomediet (2) i respektive mätsond erhålles en utsignal, som är direkt proportionell mot trycknivån i vardera mätpunktema efter utbalanseringen.Figure 1 schematically shows the present measuring system, whereby the the principles are outlined. Each measuring probe (7,8) is permanently mounted at a fixed distance between the two measuring points. It is assumed that there is a pressure difference at this constant distances. By means of separate pressure regulators (11, 12), the respective probe diaphragm (9,10) by means of, for example, a hydraulic valve in the regulator and thereby is registered by a measuring device (13) the pressure difference dP between the servo media in the respective circuit. ' The pressure regulators are in principle fed by a pressurized servo medium from the joint connection (1). The back pressure in each probe corresponds to the balancing, i.e. after equilibrium is reached between the pressure in the servo medium (2) and the pressure on the outside of the sensor, against the 10 15 506 368 3 prevailing pressure on the outside of the diaphragm. By connecting the differential pressure gauge (13) to the servo medium (2) in the respective measuring probe, an output signal is obtained, which is directly proportional against the pressure level in each of the measuring points after balancing.

Trycket i vardera mätsonden registreras genom separata rörelsegivaré (5,6) och respektive signal (3,4) användes för styrningen av tryckregulatorerna (11,12).The pressure in each measuring probe is registered by separate motion sensors (5,6) and the respective signal (3,4) is used for controlling the pressure regulators (11,12).

Genom mätanordningen möjliggöres först och främst densitetsmätning hos vätskor under svära förhållanden, tex korrosiva betingelser eller med svårhanterliga egenskaper som hög viskositet, klibbighet, sedimenteringsbenägenheter etc, då t ex olika typer av massflödesmätare, vägningsapparamr m fl fungerar mindre bra. Den föreliggande an- ordningen saknar helt och hållet öppna intag och detta är en bidragande orsak till att olägenheter med igensatta flödeskanaler och tryckupptagningszoner kan reduceras betydligt, varigenom tillsynsintervallen kan ökas. Justeringsbehovet hos det konstruktions- mässigt sett mycket enkla mätsystemet är därigenom minimalt jämfört med tidigare känd apparatur för densitetsmätning.The measuring device first and foremost enables density measurement of liquids under severe conditions, such as corrosive conditions or with difficult-to-handle properties such as high viscosity, tackiness, sedimentation tendencies, etc., then for example different types of mass feasibility meter, weighing device frame m fl works less well. The present application the scheme lacks completely open intakes and this is a contributing reason why inconveniences with clogged fl fate channels and pressure absorption zones can be reduced significantly, whereby the supervision intervals can be increased. The need for adjustment of the design In terms of very simple measurement system, this is minimal compared to previously known density measurement apparatus.

Icke desto mindre torde appliceringsmöjlighetema vara betydande inom andra områden än densitetsmätning. Som exempel på tänkbara tillämpningar kan nämnas mätning av flödeshastigheter genom venturirör, nivåmätning i cisterner, utprovning av aerodynamiska och hydrodynamiska strömningsförlopp mm.Nevertheless, the application possibilities should be significant in others areas other than density measurement. Examples of possible applications can be mentioned measurement of fl fatal velocities through venturi, level measurement in cisterns, testing of aerodynamic and hydrodynamic flow processes etc.

Claims (6)

10 15 506 568 4 Patentkrav10 15 506 568 4 Patent claims 1. Anordning för differenstryckrnätning i ett fluidum genom tryckavkänning med tvâ rnätsonder, k ä n n e t e c k n a d a v att vardera sonden (7,8) är fast monterad vid ett förbestämt avstånd mellan de bägge mätställena, att sondmembran (9,10) var för sig via ett servomedium står i förbindelse med separata tryckregulatorer (11,12), varigenom respektive sondmembran pâ basis av en styrsignal för membrandeflexionen är utbalanse- ringsbart till jämvikt mellan omgivande fluidum och servomediet, genom vilket respektive mätsond står i förbindelse med ett gemensamt mätdon (13) för differenstrycket.Device for differential pressure meshing in a unit by pressure sensing with two mesh probes, characterized in that each probe (7, 8) is fixedly mounted at a predetermined distance between the two measuring points, that the probe diaphragm (9, 10) is separately via a servo medium is connected to separate pressure regulators (11,12), whereby the respective probe diaphragm on the basis of a control signal for diaphragm fl excision can be balanced to equilibrium between ambient fl uidum and the servo medium, through which each measuring probe is connected to a common measuring device (13) for the differential pressure . 2. Anordning enligtkrav 1, kännetecknad avattanordningenär ansluten till en dator med regler- och logikfunktion för uppföljning av fluidets densitet.Device according to claim 1, characterized by the device being connected to a computer with control and logic function for monitoring the density of the id uid. 3.» Anordning enligt krav 1, k ä n n e t e c k n a d a v att servomediet utgöres av en gas.3. » Device according to claim 1, characterized in that the servo medium consists of a gas. 4. Anordning enligt krav 1, k ä n n e t e c k n a d a v att servomediet utgöres av en inert vätska med låg elektrisk ledníngsförmága.4. Device according to claim 1, characterized in that the servo medium consists of an inert liquid with low electrical conductivity. 5. Anordning enligt något av föregående krav, k ä n n e t e c k n a d a v att sturrnna membran med liten tryckarea användes.Device according to one of the preceding claims, characterized in that small membranes with a small pressure area are used. 6. Användning av anordningen enligt något av föreliggande krav vid densitets- mätning i cisterner med varierande vätskenivâ.Use of the device according to any one of the present claims for density measurement in tanks with varying liquid levels.
SE9601581A 1996-04-25 1996-04-25 Device for differential pressure measurement as well as use of the device for density measurement SE506368C2 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
SE9601581A SE506368C2 (en) 1996-04-25 1996-04-25 Device for differential pressure measurement as well as use of the device for density measurement
AU27204/97A AU2720497A (en) 1996-04-25 1997-04-24 Differential pressure device
EP97921056A EP0895582A1 (en) 1996-04-25 1997-04-24 Differential pressure device
PCT/SE1997/000690 WO1997040350A1 (en) 1996-04-25 1997-04-24 Differential pressure device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE9601581A SE506368C2 (en) 1996-04-25 1996-04-25 Device for differential pressure measurement as well as use of the device for density measurement

Publications (3)

Publication Number Publication Date
SE9601581D0 SE9601581D0 (en) 1996-04-25
SE9601581L SE9601581L (en) 1997-10-26
SE506368C2 true SE506368C2 (en) 1997-12-08

Family

ID=20402343

Family Applications (1)

Application Number Title Priority Date Filing Date
SE9601581A SE506368C2 (en) 1996-04-25 1996-04-25 Device for differential pressure measurement as well as use of the device for density measurement

Country Status (4)

Country Link
EP (1) EP0895582A1 (en)
AU (1) AU2720497A (en)
SE (1) SE506368C2 (en)
WO (1) WO1997040350A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AUPP240198A0 (en) 1998-03-17 1998-04-09 Resmed Limited An apparatus for supplying breathable gas
FR3047067B1 (en) 2016-01-22 2019-07-05 Elvesys SYSTEM FOR MEASURING LIQUID FLOW AND USE THEREOF
FR3126773B1 (en) 2021-09-08 2023-09-01 Elvesys LIQUID FLOW MEASUREMENT SYSTEM IN A MICRO-FLUIDIC PIPING

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1149592B (en) * 1982-02-10 1986-12-03 Valcom Di Valletti E TRANSMITTER DEVICE STRUCTURE FOR MEASURING THE OPERATING PRESSURE OF A SYSTEM
US4561307A (en) * 1984-01-26 1985-12-31 Smith George E Liquid differential pressure measurement using a vertical manifold
US4614118A (en) * 1985-02-12 1986-09-30 Chevron Research Company Non-compliant pressure cell
US4625553A (en) * 1985-04-12 1986-12-02 Dresser Industries, Inc. System to determine the level and weight of liquid in a tank or the like

Also Published As

Publication number Publication date
SE9601581L (en) 1997-10-26
EP0895582A1 (en) 1999-02-10
WO1997040350A1 (en) 1997-10-30
AU2720497A (en) 1997-11-12
SE9601581D0 (en) 1996-04-25

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