[go: up one dir, main page]

WO1994018531A1 - Appareil et procede de determination de la quantite d'un flux incident de rayonnement electromagnetique - Google Patents

Appareil et procede de determination de la quantite d'un flux incident de rayonnement electromagnetique Download PDF

Info

Publication number
WO1994018531A1
WO1994018531A1 PCT/GB1994/000263 GB9400263W WO9418531A1 WO 1994018531 A1 WO1994018531 A1 WO 1994018531A1 GB 9400263 W GB9400263 W GB 9400263W WO 9418531 A1 WO9418531 A1 WO 9418531A1
Authority
WO
WIPO (PCT)
Prior art keywords
bodies
incident
flux
electromagnetic radiation
radiation
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
PCT/GB1994/000263
Other languages
English (en)
Inventor
Amos Christopher Dexter
Graham Keith Earp
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.)
EA Technology Ltd
Original Assignee
EA Technology Ltd
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 EA Technology Ltd filed Critical EA Technology Ltd
Publication of WO1994018531A1 publication Critical patent/WO1994018531A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/10—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors
    • G01J5/12—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors using thermoelectric elements, e.g. thermocouples
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K17/00—Measuring quantity of heat
    • G01K17/06—Measuring quantity of heat conveyed by flowing media, e.g. in heating systems e.g. the quantity of heat in a transporting medium, delivered to or consumed in an expenditure device
    • G01K17/08—Measuring quantity of heat conveyed by flowing media, e.g. in heating systems e.g. the quantity of heat in a transporting medium, delivered to or consumed in an expenditure device based upon measurement of temperature difference or of a temperature
    • G01K17/20—Measuring quantity of heat conveyed by flowing media, e.g. in heating systems e.g. the quantity of heat in a transporting medium, delivered to or consumed in an expenditure device based upon measurement of temperature difference or of a temperature across a radiating surface, combined with ascertainment of the heat transmission coefficient
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/02—Constructional details
    • G01J5/06—Arrangements for eliminating effects of disturbing radiation; Arrangements for compensating changes in sensitivity
    • G01J2005/066—Differential arrangement, i.e. sensitive/not sensitive
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/10—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors
    • G01J5/12—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors using thermoelectric elements, e.g. thermocouples
    • G01J2005/126—Thermoelectric black plate and thermocouple

Definitions

  • the apparatus could also be used to investigate the radiative and convective heating mechanisms associated with a particular oven heating process in order to gain a better understanding of that process, to evaluate and optimise oven design and to provide a bench mark to enable comparative measurements between ovens of different types.
  • the apparatus could also be used to investigate problems such as non-uniform heating of work pieces and to evaluate and optimise infra-red emitter design.
  • a necessary feature of any apparatus that is to compare radiative fluxes in ovens with differing source temperatures is that it should give the same response with the same radiative flux regardless of the temperature of the source.
  • many of the commonly available infra-red detectors include photodiodes and other quantum devices which give a differing response for the same flux depending on the source temperature or rather the admixture of quantal energies. For this reason such devices are unsuitable as a basis for a broad band radiation flux measuring apparatus.
  • the detector was designed for the measurment of direct solar radiation flux and comprises two manganin strips 10 and 12 which are blackened on their upper surfaces. The underside of the strips 10 and 12 are attached to the junctions of two thermocouples 14 and 16 each of which is connected to a sensitive mirror galvanometer 18.
  • One of the manganin strips 12 is arranged so as to be capable of being heated by an electric current from a battery 20.
  • a variable resistor 22 interposed between the manganin strip 12 and the battery 20 provides a means of regulating the current and thus the amount of heat that is generated.
  • a second galvanometer 24 provides a means of measuring this current.
  • the two manganin strips 10 and 12 are disposed at one end of a cylindrical tube which at the other end is provided with two apertured slots, each in alignment with a respective one of the two manganin strips 10 and 12.
  • one of the apertured slots is covered by a shield and the pyroheliometer tube directed toward the sun.
  • one of the manganin strips 10 is exposed to the suns rays while the other strip 12 is shaded.
  • This generates a temperature difference between the two strips 10 and 12 the first of which is heated by the absorption of the incident solar radiation while the second, being shaded, exhibits no change in temperature.
  • an electric current is generated in the circuit of the the thermocouple.
  • the quantity of heat released in the second strip 12 will provide a measure of the quantity of solar radiation absorbed by the first strip 10.
  • the absence of a current in the circuit of the first galvanometer 18 determines the moment when the temperature of the two strips 10 and 12 is equal.
  • the second galvanometer 24 it is possible to record the size of the current necessary to obtain a zero reading in the first galvanometer 18. From this reading the quantity of heat released in the second strip Q may be calculated by virtue of the following equation:
  • S is the flux of direct solar radiation
  • ⁇ is the absorbtivity of the surface of the strip
  • A is the surface area of the strip.
  • Angstrom Compensation Pyroheliometer does not produce fully reliable results as the above theory does not take into account certain factors that influence the Pyroheliometer readings. As a result the readings obtained by each instrument must be compared and adjusted so as to conform to an International standard.
  • thermoelements are disposed either in a rectangular arrangement or radially from the centre of a flux receiving surface, respective opposite ends of the same strip being either sooted black or whitened with magnesia.
  • the receiving surface has the appearance of a black and white chequer board.
  • a hemispherical glass cover prevents the occurrence of wind effects.
  • the Yanishevsky Pyronometer is however a relative instrument and so must be calibrated to an International standard. Like other pyronometers the Yanishevsky Pyronometer displays an angular dependance of sensitivity and also a pronounced selectivity of sensitivity for radiation of different wavelengths. This necessitates the introduction of so called angular and spectral corrections to the readings in the measurement of diffuse radiation which take into account the differences between the anngular and spectral distributions of diffuse and direct solar radition intensity. Again it is not apparent how the Yanishevsky Pyranometer could be adapated for use within an industrial oven.
  • an apparatus for determining the quantity of an incident flux of electromagnetic radiation comprising first and second bodies having different coefficients of interaction with the incident radiation, means to monitor the temperatures of said bodies, heating means associated with at least one of said bodies, control means responsive to the monitored temperatures to control said heating means so as to minimize temperature differences therebetween and to provide a signal representative of the power delivered to the heating means, and computing means responsive to said power signal to compute a value for the quantity of the flux of electromagnetic radiation incident upon the bodies.
  • a second and independent heating means may be provided in association with the other of said two bodies.
  • the or each heating means may comprise a resistive heating element in intimate contact with an undersurface of the body concerned.
  • said first and second bodies are substantially planar.
  • said first and second bodies may be contained within a sensor unit remote from said control means and coupled thereto by means of an umbilical cable.
  • a method of determining the quantity of an incident flux of electromagnetic radiation comprising the steps of providing first and second bodies having different coefficients of interaction with the incident radiation, exposing said bodies to the incident flux of electromagnetic radiation, measuring the temperatures of said bodies, heating the colder of said two bodies so as to minimize any temperature difference therebetween, measuring the quantity of power necessary to so heat said colder of the two bodies and calculating a value for the quantity of the flux of electromagnetic radiation incident upon the bodies on the basis of said measured values.
  • the method may comprise the additional step of computing the total heat flux arriving at said first or second bodies.
  • the additional step of computing the total heat flux arriving at said first or second bodies may include measuring the quantity of heat flowing through the thermally insulating supporting member.
  • FIG. 1 a schematic plan view of an apparatus 110 for measuring an incident flux of radiation
  • a sensor unit 112 and a controller 114 interconnected by a heat-resistant umbilical cable 116.
  • the two bodies 118 and 120 are mounted on a thermal insulation board 122.
  • the two bodies 118 and 120 are adapated in a manner to be described so as to have substantially the same thermal mass whilst at the same time having different coefficients of interaction with an incident flux of radiation.
  • the bodies are adapted so that a first of them 118 is capable of reflecting up to 96% of an incident flux of infra-red radiation while the second 120 is capable of absorbing up to 98% of the same incident flux.
  • elements 124 and 126 may simply comprise a resistive layer which is printed or otherwise applied to the under surface of the body concerned. In this way the thermal lag previously identified is minimised thereby simplifying the task of the controller 114 in minimising any temperature differences between the reflecting and absorbing bodies 118 and 120. As a result the apparatus as a whole 110 may respond more quickly to rapid changes in the incident flux while on a more local level thermal runaway within the heating elements is prevented as a result of some parts of the strip element becoming hotter than others.
  • each of the two temperature sensors 128 and 130 preferably comprise a thermocouple.
  • the two temperature sensors 128 and 130 preferably comprise a matched pair of 0.5mm diameter Inconnel sheathed type K thermocouples each of which is cemented into a blind hole drilled in the centre of the under surface of the bodies concerned using a high temperature adhesive.
  • one or both of the temperature sensors 128 and 130 may comprise a resistive temperature sensing element printed directly on to the under surface of the two bodies 118 and 120. As a consequence this alternative arrangement would simplify the manufacturing of the apparatus whilst at the same time improving the thermal response of the computed flux measurement.
  • the apparatus 110 should only measure the radiative heat flux incident upon the upper surfaces 140 of the two bodies 118 and 120 and since the apparatus 110 is to be used in ovens which typically have radiant panels on each of their internal surfaces, it follows that the two bodies 118 and 120 should preferably be thermally isolated from a flux of radiation that would otherwise be incident upon their respective under surfaces.
  • the rear face and sides of the sensor unit 112 are preferably made of a reflective metal having a sufficient thickness to provide the walls of the sensor unit 112 with a reasonable thermal conductivity in their lateral directions. In this way the high reflectance will reduce the amount of heat that is conducted to the internal surfaces of the sensor unit 112 while the high conductivity will ensure that different parts of the sensor unit 112 are not at widely differing temperatures.
  • the insulation board 122 on which the two bodies 118 and 120 are mounted preferably extends laterally beyond the bodies by an amount greater than the thickness of the board. Furthermore, the area of the thermal insulation board 122 at the front of the sensor unit 112 and around the two bodies 118 and 120 is preferably covered with a metal plate having a similar thermal capacity to that of the bodies themselves and is preferably coated with an absorbing material.
  • the heat resistant umbilical cable 116 interconnecting the sensor unit 112 and the controller 114 comprises a stainless steel flexible conduit of typically 4 metres in length.
  • the controller 114 which is preferably battery powered and microprocessor based is enclosed within a housing capable of withstanding an external temperature not exceeding 300°C for at least 30 minutes. In this way should the need arise, both the sensor unit 112 and the controller 114 may be passed through an oven on a continuous conveyor. On other oaccasions, provided the umbilical cable 116 is long enough, only the sensor unit 112 need be placed in the oven enabling the controller 114 to remain outside.
  • the controller 114 preferably operates under the control of an algorithm that in response to a detected temperature difference between the bodies 118 and 120 delivers a slowly varying power to the cooler of the two bodies. During this period the flux computation is derived from a weighted average of the applied power levels.
  • a suitable weighting function associating temperature rise to the application of power might be derived from the temperature record after a short duration pulse of power.
  • the weighting function can be regarded as the proportion of the pulse that is realised as a temperature rise in time intervals after its application while the time to realise half the energy of the pulse can be defined as the delay time.
  • the delay time will depend on the thermal resistance between the heating element and the associated temperature sensor.
  • the weighting function may be established from a state in which both the bodies 118 and 120 and the thermal insulation board 122 are at the same temperature. Whilst the weighting function thus derived cannot be expected to be exactly appropriate when the temperature of the sensor unit 112 is different, the small extent to which the weighting function becomes inappropriate can be regarded as an uncertainty in the average delay time associated with non-repeatability.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Radiation Pyrometers (AREA)

Abstract

L'invention se rapporte à un appareil (110) servant à déterminer la quantité d'un flux incident de rayonnement électromagnétique et comprenant des premier et second corps (118, 120) possédant des coefficients différents d'interaction avec le rayonnement incident, des éléments pour contrôler les températures de ces corps (118, 120), des éléments de chauffage associés à au moins un de ces corps (118, 120), des éléments de commande (114) sensibles aux températures contrôlées pour commander l'élément de chauffage de façon à minimiser les différences de température et à générer un signal représentatif de l'énergie fournie à l'élément de chauffage, et un élément de calcul (114) sensible à ce signal d'énergie pour calculer une valeur déterminant la quantité de flux du rayonnement électromagnétique incident sur les corps (118, 120). Un procédé de détermination de la quantité d'un flux incident de rayonnement électromagnétique comprenant des premier et second corps (118, 120) possédant différents coefficients d'interaction avec le rayonnement incident consiste à exposer ces corps au flux incident du rayonnement électromagnétique, à mesurer leurs températures, à chauffer le plus froid de ces deux corps (118, 120) de manière à minimiser toute différence de température entre eux, à mesurer la quantité d'énergie nécessaire pour chauffer ainsi le plus froid de ces deux corps, et à calculer une valeur déterminant la quantité du flux du rayonnement électromagnétique incident sur les corps (118, 120) sur la base de ces valeurs mesurées.
PCT/GB1994/000263 1993-02-11 1994-02-10 Appareil et procede de determination de la quantite d'un flux incident de rayonnement electromagnetique Ceased WO1994018531A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9302745A GB2275106B (en) 1993-02-11 1993-02-11 Apparatus and method for determining the quantity of an incident flux of electromagnetic radiation
GB9302745.6 1993-02-11

Publications (1)

Publication Number Publication Date
WO1994018531A1 true WO1994018531A1 (fr) 1994-08-18

Family

ID=10730272

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1994/000263 Ceased WO1994018531A1 (fr) 1993-02-11 1994-02-10 Appareil et procede de determination de la quantite d'un flux incident de rayonnement electromagnetique

Country Status (2)

Country Link
GB (1) GB2275106B (fr)
WO (1) WO1994018531A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2797034B1 (fr) * 1999-07-29 2001-10-26 Francis Bourrieres Dispositif de conversion reciproque de temperature en energie thermique echangee a travers un milieu gazeux ou le vide
FR2797035B1 (fr) * 1999-07-29 2001-08-31 Francis Bourrieres Dispositif de conversion reciproque de temperature en energie thermique echangee a travers un milieu gazeux ou le vide
GB2367891B (en) 2000-10-09 2004-07-07 United Biscuits Ltd Improvements in and relating to the measurement of heat flux in a heated chamber

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1648204A1 (de) * 1967-01-27 1971-07-08 Friedrichs Theodor Strahlungsbilanzmesser
WO1988007180A1 (fr) * 1987-03-20 1988-09-22 Robert Bosch Gmbh Detecteur de rayonnement thermique

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8528517D0 (en) * 1985-11-20 1985-12-24 United Biscuits Ltd Radiant heat measurement

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1648204A1 (de) * 1967-01-27 1971-07-08 Friedrichs Theodor Strahlungsbilanzmesser
WO1988007180A1 (fr) * 1987-03-20 1988-09-22 Robert Bosch Gmbh Detecteur de rayonnement thermique

Also Published As

Publication number Publication date
GB2275106A (en) 1994-08-17
GB9302745D0 (en) 1993-03-24
GB2275106B (en) 1997-03-05

Similar Documents

Publication Publication Date Title
EP0063415B1 (fr) Cible pour calibrer et éprouver des dispositifs de détection infrarouges
US5178464A (en) Balance infrared thermometer and method for measuring temperature
US5054936A (en) Sensor for active thermal detection
US6626835B1 (en) Infrared sensor stabilizable in temperature, and infrared thermometer with a sensor of this type
US5247185A (en) Regulated infrared source
US4480372A (en) Process of fabricating target for calibrating and testing infrared detection devices
US4063095A (en) Balancing radiometer
US20040136434A1 (en) Laminated heat flux indicating device
JP2012225717A (ja) 赤外線センサ装置
JPH0666639A (ja) 赤外線温度計
WO1994018531A1 (fr) Appareil et procede de determination de la quantite d'un flux incident de rayonnement electromagnetique
US3355589A (en) Constant sensitivity differential radiometer
RU2227905C1 (ru) Тепловой приемник излучения
JPH09264792A (ja) 非接触温度センサ
Kendall Sr The JPL standard total-radiation absolute radiometer
US6437331B1 (en) Bolometer type infrared sensor with material having hysterisis
Kendall Primary absolute cavity radiometer
US2627530A (en) Ambient-temperature compensated device
WO2022235154A1 (fr) Capteur thermique, système de mesure et procédé d'estimation d'une température de l'air et/ou d'un coefficient de transfert de chaleur par convection
JPH0737911B2 (ja) 開口部の熱流計測装置及び熱流計測方法
Gaviot et al. Thin foil planar radiometers: application for designing contactless sensors
JP2009266506A (ja) 誘導加熱調理器
Lemzyakov et al. The use of RuO2 resistors as broadband low-temperature radiation sensors
JPH07301566A (ja) 輻射熱センサ
CN111721426A (zh) 热电堆传感器及其控制方法

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase