DE3230487A1 - Method for measuring low mass flows using a thermal principle - Google Patents

Method for measuring low mass flows using a thermal principle

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Publication number
DE3230487A1
DE3230487A1 DE19823230487 DE3230487A DE3230487A1 DE 3230487 A1 DE3230487 A1 DE 3230487A1 DE 19823230487 DE19823230487 DE 19823230487 DE 3230487 A DE3230487 A DE 3230487A DE 3230487 A1 DE3230487 A1 DE 3230487A1
Authority
DE
Germany
Prior art keywords
low mass
mass flows
measuring low
measuring
pipe
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.)
Ceased
Application number
DE19823230487
Other languages
German (de)
Inventor
Axel Dipl.-Ing. 6716 Dirmstein Plattes
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Priority to DE19823230487 priority Critical patent/DE3230487A1/en
Publication of DE3230487A1 publication Critical patent/DE3230487A1/en
Ceased legal-status Critical Current

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Classifications

    • 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
    • G01F1/68—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 thermal effects
    • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
    • G01F1/6847—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow where sensing or heating elements are not disturbing the fluid flow, e.g. elements mounted outside the flow duct
    • 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
    • G01F1/68—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 thermal effects

Landscapes

  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Volume Flow (AREA)

Abstract

The method is suitable for measuring the mass flow of gases and liquids in a range from 50 g/h to 500 g/h. It operates basically in conformity with the known thermo-anemometric principle. By contrast with other similarly operating devices, here the temperature gradient is kept constant temporally and spatially along the tube wall under all flow conditions. This measure renders the measurement result independent of the thermal conductivity of the medium.

Description

Gegenstand der Erfindung ist ein Verfahren zur MessungThe invention relates to a method for measurement

geringer Massenströme von Gasen und Flüssigkeiten auf thermischer Grundlage im Meßbereich von einigen g/Stunde bis zu mehreren kg/Stunde. Dazu wird die mediendurchströmte Rohrleitung elektrisch beheizt, sodaß zwischen zwei Meßfühlern ein bestimmtes Temperaturprofil entsteht, das durch das strömende Medium verschoben wird.low mass flows of gases and liquids on thermal Basis in the measuring range from a few g / hour to several kg / hour. This will be the pipeline through which the medium flows electrically heated, so that between two sensors a certain temperature profile is created, which is shifted by the flowing medium will.

Thermische Durchflußmesser auf dieser Grundlage sind bekannt. Der Stand der Technik wird beschrieben in dem Handbuch " Messen, Steuern und Regeln in der chemischen Technik t Nachteilig bei allen bisher bekannten thermischen Durchflußmessern ist jedoch die Abhängigkeit des Meßsignals von der Wärmeleitfähigkeit des strömenden Mediums und die Nichtlinearität des direkten Ausgangssignals in Abhängigkeit des Massendurchflusses.Thermal flow meters based on this are known. Of the The state of the art is described in the manual "Measurement, control and regulation In chemical engineering, it is disadvantageous for all previously known thermal flow meters however, the dependence of the measurement signal on the thermal conductivity of the flowing Medium and the non-linearity of the direct output signal as a function of the Mass flow rate.

Aufgabe der vorliegenden Erfindung ist es, diese Nachteile zu beseitigen. Dies wird erreicht durch die Aufrechterhaltung eines linearen Temperaturgefälles zwischen zwei Meßfühlern entlang des mediendurchströmten Rohres gegen die Strömungsrichtung mit Hilfe einer elektrischen Heizung.The object of the present invention is to eliminate these disadvantages. This is achieved by maintaining a linear temperature gradient between two sensors along the pipe through which the medium flows against the direction of flow with the help of an electric heater.

Unter diesen Bedingungen ist die zur Aufrechterhaltung einer bestimmten Temperaturdifferenz erforderlichen Heizleistung dem Massendurchfluß direkt proportional.Under these conditions is the maintenance of a certain Temperature difference required heating power directly proportional to the mass flow.

Ein weiterer entscheidender Vorteil ist die Unabhängigkeit des Ausgangssignals von der Wärmeleitfahigkeit des strömenden Mediums.Another decisive advantage is the independence of the output signal on the thermal conductivity of the flowing medium.

1.) Hrsg. J. Hengstenberg, B. Sturm, D. Winkler Band I, Springer Berlin, Heidelberg, New York 1980 Störeinflüsse, die durch Änderung der Umgebungs- und der Mediumstemperatur verursacht werden können, werden dadurch verhindert, daß die Konvektion durch ein geeignetes Isoliermaterial zwischen dem mediendurchströmten Rohr und dem Schutzrohr unterbunden wird.1.) Eds. J. Hengstenberg, B. Sturm, D. Winkler Volume I, Springer Berlin, Heidelberg, New York 1980 Interference caused by changing the Ambient and medium temperature are prevented, that the convection flows through a suitable insulating material between the media Tube and the protective tube is prevented.

Figur I zeigt einen Schnitt durch eine Meßepparatur Durch ein Hochdruckrohr ( 1 ), fließt das zu messende Medium, welches durch eine radiale Heizwicklung ( 2 auf eine erhöhte Temperatur gebracht wird. Durch zwei Temperaturfühler ( 3 , 4 ) wird die konstantzuhaltende Temperaturdifferenz gemessen.FIG. I shows a section through a measuring fixture through a high pressure pipe (1), the medium to be measured flows through a radial heating coil ( 2 is brought to an elevated temperature. With two temperature sensors (3, 4 ) the temperature difference to be kept constant is measured.

Zum Schutz vor Störeinflüssen, sowie zur allgemeinen Sicherheit werden die beiden Verschlußdeckel ( 5 sowie das Schutzrohr ( 6 ) angebracht. Eine thermische Isoliermasse ( 7 ) beseitigt Störungen durch schnelle Schwankllngen der Umgebungstemperatur. Mittels der 0-Ringe ( 8 ) wird die Me3'apparatur nach außen abgedichtet.To protect against interference, as well as for general safety the two sealing caps (5 and the protective tube (6) are attached. A thermal Insulating compound (7) eliminates malfunctions caused by rapid fluctuations in the ambient temperature. The measuring apparatus is sealed from the outside by means of the O-rings (8).

Claims (3)

Patent ansprüche: 1.) Das Verfahren zur Messung geringer Massenströme auf thermischer Grundlage ist dadurch gekennzeichnet, daß entlang eines mediendurchströmten Rohres zwischen zwei Meßfühlern innerhalb des Meßbereichs ein lineares Temperaturgefälle gegen die Strömungsrichtung aufrecht erhalten wird.Patent claims: 1.) The method for measuring low mass flows on a thermal basis is characterized in that the medium flows along a Pipe a linear temperature gradient between two sensors within the measuring range is maintained against the direction of flow. 2.) Verfahren nach Anspruch 1 dadurch gekennzeichnet, daß die Temperaturdifferenz zwischen den beiden Meßfühlern durch eine geeignete Regelschaltung konstant gehalten wird.2.) Method according to claim 1, characterized in that the temperature difference kept constant between the two sensors by a suitable control circuit will. 3.) Verfahren nach Anspruch 1 - 2 dadurch gekennzeichnet, daß der freie Raum zwischen dem mediendurchströmten Rohr und dem Schutzrohr zur Unterbindung einer Konvektion mit einem geeigneten Isoliermaterial ausgefüllt ist.3.) The method according to claim 1 - 2, characterized in that the Free space between the pipe through which the medium flows and the protective pipe to prevent it a convection is filled with a suitable insulating material.
DE19823230487 1982-08-17 1982-08-17 Method for measuring low mass flows using a thermal principle Ceased DE3230487A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19823230487 DE3230487A1 (en) 1982-08-17 1982-08-17 Method for measuring low mass flows using a thermal principle

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19823230487 DE3230487A1 (en) 1982-08-17 1982-08-17 Method for measuring low mass flows using a thermal principle

Publications (1)

Publication Number Publication Date
DE3230487A1 true DE3230487A1 (en) 1984-02-23

Family

ID=6171006

Family Applications (1)

Application Number Title Priority Date Filing Date
DE19823230487 Ceased DE3230487A1 (en) 1982-08-17 1982-08-17 Method for measuring low mass flows using a thermal principle

Country Status (1)

Country Link
DE (1) DE3230487A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3419504A1 (en) * 1984-05-25 1986-01-23 Günther Dipl.-Ing. 2201 Kollmar Weber FLOW GUARD
DE3713301A1 (en) * 1987-04-18 1988-11-03 Becker Helmut Dipl Wirtsch Ing Process for measuring flow quantities and thermal flow transmitter for this

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3419504A1 (en) * 1984-05-25 1986-01-23 Günther Dipl.-Ing. 2201 Kollmar Weber FLOW GUARD
DE3713301A1 (en) * 1987-04-18 1988-11-03 Becker Helmut Dipl Wirtsch Ing Process for measuring flow quantities and thermal flow transmitter for this

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OP8 Request for examination as to paragraph 44 patent law
8131 Rejection