GB788538A - Improvements in or relating to heat-conduction manometers - Google Patents

Improvements in or relating to heat-conduction manometers

Info

Publication number
GB788538A
GB788538A GB12001/54A GB1200154A GB788538A GB 788538 A GB788538 A GB 788538A GB 12001/54 A GB12001/54 A GB 12001/54A GB 1200154 A GB1200154 A GB 1200154A GB 788538 A GB788538 A GB 788538A
Authority
GB
United Kingdom
Prior art keywords
bridge
chamber
temperature
casing
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.)
Expired
Application number
GB12001/54A
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.)
WC Heraus GmbH and Co KG
Original Assignee
WC Heraus GmbH and Co KG
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 WC Heraus GmbH and Co KG filed Critical WC Heraus GmbH and Co KG
Publication of GB788538A publication Critical patent/GB788538A/en
Expired legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01LMEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L21/00Vacuum gauges
    • G01L21/10Vacuum gauges by measuring variations in the heat conductivity of the medium, the pressure of which is to be measured
    • G01L21/12Vacuum 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

Landscapes

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

Abstract

788,538. Heat conduction manometers. HERAEUS GES., W. C. April 26, 1954 [April 25, 1953; Nov. 27, 1953], No. 12001/54. Class 40 (1). In a heat conduction manometer comprising a casing 7 containing a sealed measuring chamber 8 communicating only with the pressure chamber and a similar reference chamber 9 containing gas at constant pressure, the chambers each contain a small semi-conductor bead supported by thin electrodes. The beads 1a, 1b form the measuring and reference arms respectively of a Wheatstone bridge which is provided with a positive temperature coefficient resistor 20 in parallel with the bridge instrument to compensate for changes in ambient temperature. Through each of electrodes 2a, 2b, which are preferably of Pt or Pt alloy not more than 25 thick and circa 25 to 50 mm. long, heat conduction is less than 4 x 10<SP>-7</SP> cols./‹ C. temperature difference between its ends, and thus no greater than the heat loss through the gas the variations of which with pressure make the measurement possible. The casing 7, e.g. of brass or Cu which may be water cooled to maintain its temperature constant, is fixed to a flange 6 having a hole communicating with vacuum chamber 23. To stop bead poisoning and electrode corrosion any vapours present in the chamber are condensed on cooled baffles in the communication hole. The other bridge resistors may be external to or contained within the casing 7. Compensation for variations in sensitivity and of the zero point with such changes in ambient temperature as may occur may be effected by placing positive temperature coefficient resistors, e.g. 18 and 19, in the other bridge arms in series with the normal balancing resistors 14, 15 which may also have positive temperature coefficients and making one, 18, adjustable; by a temperature sensitive resistor 22 in series with the bridge instrument; by a negative temperature coefficient resistor 21 in the supply line of the bridge; or as shown by a combination of all these methods. In an alternative arrangement, the bridge instrument is replaced by an amplifier to permit of indication at a remote point.
GB12001/54A 1953-04-25 1954-04-26 Improvements in or relating to heat-conduction manometers Expired GB788538A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE788538X 1953-04-25

Publications (1)

Publication Number Publication Date
GB788538A true GB788538A (en) 1958-01-02

Family

ID=6699481

Family Applications (1)

Application Number Title Priority Date Filing Date
GB12001/54A Expired GB788538A (en) 1953-04-25 1954-04-26 Improvements in or relating to heat-conduction manometers

Country Status (1)

Country Link
GB (1) GB788538A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3230405A1 (en) * 1981-08-28 1983-03-10 Boc Ltd., London GAS PRESSURE MEASURING CIRCUIT

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3230405A1 (en) * 1981-08-28 1983-03-10 Boc Ltd., London GAS PRESSURE MEASURING CIRCUIT

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