EP0896659A1 - Circuit de compensation de temperature d'un vacuometre dont le fonctionnement est fonde sur la conduction thermique - Google Patents

Circuit de compensation de temperature d'un vacuometre dont le fonctionnement est fonde sur la conduction thermique

Info

Publication number
EP0896659A1
EP0896659A1 EP97906191A EP97906191A EP0896659A1 EP 0896659 A1 EP0896659 A1 EP 0896659A1 EP 97906191 A EP97906191 A EP 97906191A EP 97906191 A EP97906191 A EP 97906191A EP 0896659 A1 EP0896659 A1 EP 0896659A1
Authority
EP
European Patent Office
Prior art keywords
compensation
branch
temperature
circuit
heat conduction
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
EP97906191A
Other languages
German (de)
English (en)
Inventor
Gerhard KÜSTER
Norbert Rolff
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.)
Leybold GmbH
Original Assignee
Leybold Vakuum GmbH
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 Leybold Vakuum GmbH filed Critical Leybold Vakuum GmbH
Publication of EP0896659A1 publication Critical patent/EP0896659A1/fr
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L21/00—Vacuum gauges
    • G01L21/10—Vacuum gauges by measuring variations in the heat conductivity of the medium, the pressure of which is to be measured
    • G01L21/12—Vacuum gauges by measuring variations in the heat conductivity of the medium, the pressure of which is to be measured measuring changes in electric resistance of measuring members, e.g. of filaments; Vacuum gauges of the Pirani type

Definitions

  • the invention relates to a circuit for a heat conduction vacuum meter with the features of the preamble of claim 1.
  • Thermal conduction vacuum gauges are used in a pressure range that extends from the upper end of the high vacuum range (approx. 10 ⁇ 4 mbar) to far into the rough vacuum range (approx. 1000 mbar).
  • Heat conduction vacuum meters take advantage of the fact that more heat is dissipated from a temperature-dependent resistance element at higher gas pressures, that is to say with a higher particle number density, than at lower gas pressures.
  • the temperature-dependent resistance element is, for example, a measuring wire which is connected to a Wheatstone bridge. In the Pirani vacuum meter, which is not valid, a change in the resistance of the measuring wire detunes the bridge, which is used as a measure of the pressure.
  • the supply voltage at the bridge is constantly regulated in such a way that the resistance and thus the temperature of the measuring wire remain constant regardless of the heat output.
  • the current required to keep the resistance value constant is a measure of the thermal conductivity and thus of the pressure of the gas.
  • the Wheatstone's bridge is usually reduced to a minimum by adjusting the bridge supply voltage. Mood matched. The bridge supply voltage is thus the primary electrical value corresponding to the pressure.
  • the ambient temperature of the measuring wire has a disruptive influence on the measuring principle, since it determines the thermal equilibrium of the measuring wire with its surroundings via radiation and heat conduction through fastening parts.
  • it is known to switch a temperature-dependent resistor with a suitable characteristic into one of the branches of the Wheatstone bridge.
  • this temperature compensation is inadequate since the voltage drop across the compensation resistor depends not only on the ambient temperature but also on the pressure of the gas. This results in the problem of inadequate temperature compensation in the pressure end regions which generally exists in the case of heat conduction vacuum meters.
  • the present invention is based on the object of proposing a circuit for a heat conduction vacuum meter with which an accurate temperature compensation can be achieved in particular in the pressure end regions.
  • the bridge circuit has, in addition to the first branch with the measuring resistor, at least two further branches with temperature-dependent compensation resistors, it is possible to use compensation resistors with different characteristics adapted to the pressure ranges for different pressure ranges. An overall improved temperature compensation, and especially in the pressure end areas, is possible. Further advantages and details of the invention will be explained with reference to an exemplary embodiment shown in the figure.
  • the bridge circuit is designated by 1. It comprises the branch sections 2 to 5, 16, 17. Their different taps are designated 6 to 9, 18.
  • Section 2 with resistor 11 and section 3 with measuring resistor or measuring wire 12 form the measuring branch of bridge 1.
  • a first compensation branch comprises sections 4 and 5, which are each equipped with a temperature-independent resistor 13 and 14, respectively.
  • section 5 or 4 provides the temperature-dependent resistor 15, which is used for temperature compensation in a manner known per se.
  • Another compensation branch is provided parallel to the first compensation branch described. It comprises the sections 16, 17 and the intermediate tap 18. Both sections are each equipped with a temperature-independent resistor 21 and 22, respectively. Section 17 or 16 also contains the temperature-dependent resistor 23.
  • the supply voltage UR is at the taps 6, 8 of the bridge circuit 1.
  • the controlled Pirani it is controlled with the aid of the operational amplifier 24 in such a way that the measuring resistor 12 remains constant.
  • the input 25 of the operational amplifier 24 is connected via line 26 to the intermediate tap 7 of the measuring branch and the input 27 via line 28 to one of the intermediate taps 9 or 18 of the compensation branches.
  • the bridge supply voltage is the measure of the pressure.
  • the voltage UR is supplied to the display instrument 32 in a manner known per se.
  • the line 28 is connected via the line sections 33 and 34 to the taps 9 and 18 of the two compensation branches.
  • the resistor 35 is located in one of the two sections, in the other there is, for example, a field effect transistor 36. With the aid of the voltage UG applied to the gate, the field effect transistor can be switched in such a way that one of the two intermediate taps 9, 18 can be selected can be connected to the input 27 of the operational amplifier 24.
  • two compensation branches 4, 5 and 16, 17 are shown.
  • One of the two resistors 15, 23 is expediently optimized for temperature compensation in the upper pressure range and the other for temperature compensation in the lower pressure range.
  • the switchover from one compensation branch to the other is advantageously carried out in the middle pressure range.
  • the switchover is fluid.
  • the switching range can be selected via the voltage UQ.
  • the number of the existing compensation branches can be increased accordingly.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Fluid Pressure (AREA)

Abstract

L'invention concerne un circuit prévu pour un vacuomètre de conduction thermique avec un circuit en pont (1) comportant une première branche (2, 3) avec une résistance série (12) et une seconde branche (4, 5) avec une résistance (15) dépendant de la température, pour compenser les erreurs de mesure inhérentes à la température. Ce circuit comprend également un amplificateur d'opération (24) servant à réguler la tension d'alimentation du pont (UB), dont la première entrée (25) est connectée à la prise intermédiaire (7) de la branche de mesure (2, 3) du circuit en pont et dont la seconde entrée (27) est connectée à la prise intermédiaire (9) de la branche de compensation (4, 5) du circuit en pont. Afin de parvenir à une compensation relativement précise de la température, il est prévu au moins une autre branche de compensation (16, 17) parallèlement à la branche de compensation (4, 5), avec une autre résistance (23) dépendant de la température. Il est également prévu que la seconde entrée (27) de l'amplificateur d'opération (24) puisse être connectée de manière facultative aux prises intermédiaires (9, 18) des branches de compensation (4, 5; 16, 17).
EP97906191A 1996-04-30 1997-03-08 Circuit de compensation de temperature d'un vacuometre dont le fonctionnement est fonde sur la conduction thermique Ceased EP0896659A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19617238 1996-04-30
DE1996117238 DE19617238A1 (de) 1996-04-30 1996-04-30 Schaltung zur Temperaturkompensation eines Wärmeleitungsvakuummeters
PCT/EP1997/001184 WO1997041414A1 (fr) 1996-04-30 1997-03-08 Circuit de compensation de temperature d'un vacuometre dont le fonctionnement est fonde sur la conduction thermique

Publications (1)

Publication Number Publication Date
EP0896659A1 true EP0896659A1 (fr) 1999-02-17

Family

ID=7792865

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97906191A Ceased EP0896659A1 (fr) 1996-04-30 1997-03-08 Circuit de compensation de temperature d'un vacuometre dont le fonctionnement est fonde sur la conduction thermique

Country Status (4)

Country Link
EP (1) EP0896659A1 (fr)
JP (1) JP2000509151A (fr)
DE (1) DE19617238A1 (fr)
WO (1) WO1997041414A1 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6658941B1 (en) * 1997-07-21 2003-12-09 Helix Technology Corporation Apparatus and methods for heat loss pressure measurement
US6938493B2 (en) 1997-07-21 2005-09-06 Helix Technology Corporation Apparatus and methods for heat loss pressure measurement
US7249516B2 (en) * 2004-07-28 2007-07-31 Brooks Automation, Inc. Method of operating a resistive heat-loss pressure sensor
WO2006020196A1 (fr) * 2004-07-28 2006-02-23 Brooks Automation, Inc. Procedez de fonctionnement d'un capteur de pression a perte d'energie et a resistance
GB2601179A (en) * 2020-11-23 2022-05-25 Edwards Ltd Thermal conductivity vacuum gauge assembly
KR102471346B1 (ko) * 2022-06-24 2022-11-29 (주)아토벡 진공압력산출장치

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2460873A (en) * 1945-01-01 1949-02-08 Dayton H Clewell Vacuum gauge
DE1029599B (de) * 1953-11-27 1958-05-08 Heraeus Gmbh W C Heissleitervakuummeter
DE1699150U (de) * 1954-05-31 1955-05-26 Patra Patent Treuhand Vakuummesser.
US3290928A (en) * 1964-06-10 1966-12-13 Boeing Co Temperature compensated strain gage and circuit
DE2157842C3 (de) * 1971-11-22 1974-11-21 Siemens Ag, 1000 Berlin Und 8000 Muenchen Anordnung zur Temperaturkompensation für Meßbrücken
GB1515611A (en) * 1976-03-11 1978-06-28 Rosemount Eng Co Ltd Electric circuits
GB2105047B (en) * 1981-08-28 1986-04-03 British Oxygen Co Ltd Pirani gauges
GB8407192D0 (en) * 1984-03-20 1984-04-26 Lucas Ind Plc Circuit
US5069066A (en) * 1990-05-10 1991-12-03 Djorup Robert Sonny Constant temperature anemometer
DD296353A5 (de) * 1990-06-28 1991-11-28 Hochvakuum Dresden,De Schaltungsanordnung zur korrektur des temperaturfehlers von waermeleitungsvakuummetern
DE4205551A1 (de) * 1992-02-24 1993-08-26 Leybold Ag Schaltung zur temperaturkompensation eines geregelten waermeleitungsvakuummeters
DE4308433A1 (de) * 1993-03-17 1994-09-22 Leybold Ag Wärmeleitungsvakuummeter mit Meßzelle, Meßgerät und Verbindungskabel
DE4308434A1 (de) * 1993-03-17 1994-09-22 Leybold Ag Temperaturkompensation bei einem geregelten Wärmeleitungsvakuummeter

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9741414A1 *

Also Published As

Publication number Publication date
JP2000509151A (ja) 2000-07-18
DE19617238A1 (de) 1997-11-06
WO1997041414A1 (fr) 1997-11-06

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