WO1998009143A1 - Improvements in and relating to the measurement of heat flux in ovens - Google Patents
Improvements in and relating to the measurement of heat flux in ovens Download PDFInfo
- Publication number
- WO1998009143A1 WO1998009143A1 PCT/GB1997/002126 GB9702126W WO9809143A1 WO 1998009143 A1 WO1998009143 A1 WO 1998009143A1 GB 9702126 W GB9702126 W GB 9702126W WO 9809143 A1 WO9809143 A1 WO 9809143A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- sensor
- sensors
- oven
- measuring
- exposed
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K13/00—Thermometers specially adapted for specific purposes
- G01K13/04—Thermometers specially adapted for specific purposes for measuring temperature of moving solid bodies
- G01K13/06—Thermometers specially adapted for specific purposes for measuring temperature of moving solid bodies in linear movement
-
- 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
Definitions
- the invention relates to the measurement of heat flux in ovens of the kind that are suitable for use in continuous processes in which material to be heated (which may be in the form of discrete articles) is transported through the oven and is heated progressively during its passage through the oven.
- Such ovens are known as tunnel ovens because they are elongate and have at one end an entrance through which the material is introduced into the oven and, at the other end, an exit through which the material is withdrawn.
- Tunnel ovens are used for a variety of purposes, for example, to dry material or to effect the baking of food products.
- the heat flux to be measured is that incident on a surface of the material to be heated.
- the heat flux will have radiative and convective components.
- the material will normally be supported from below on the upper run of an endless band conveyor and, where the band is i perforate, the only exposed surface of the material will be its upper surface. Where the band is a mesh, the lower surface of the material will be partly exposed to the heat flux, but it is the heat flux incident on the upper surface of the material that is here of prime concern.
- the manner in which the recording means operates avoids the need for a side-by-side arrangement of the sensors because, instead of recording the data from the two sensors at the same instant, when the two sensors are at different positions along the length of the oven, the data from the two sensors are recorded at different instants so chosen that the data from one sensor, when it is in one position, is compared with data from the other sensor when it is in the same position.
- thermopile constitutes the layer of a thermally insulating material and the means for providing a signal representing the temperature difference across the layer.
- a thermopile comprises a piece of thin film of a plastics material in which are embedded thermocouples connected in series and so arranged that the cold junction of each thermocouple is located close to one surface of the film and the hot junction of each thermocouple is located close to the other surface of the film.
- the use of a plurality of thermocouples connected in series both gives a spread of readings over the area where the thermocouple junctions are situated and, more importantly, gives a larger signal for a given temperature difference. Further, because of the construction of a thermopile, it is possible to arrange that it has a small thermal capacity and hence a short response time.
- the length of the minor axis of the exposed surface of each sensor advantageously does not exceed 75 mm and preferably does not exceed 50 mm.
- the apparatus is advantageously provided with a removable extension arranged to provide a horizontal surface substantially coplanar with the upper surface of the casing and extending away from the said one end of the casing.
- a removable extension arranged to provide a horizontal surface substantially coplanar with the upper surface of the casing and extending away from the said one end of the casing.
- the recording means is arranged to log data from the sensors and from the means for measuring the gas temperature at a frequency of at least 2 sec" 1 .
- the said frequency is at least 3 sec -1 .
- the recording means is programmable to enable the apparatus to be used at different conveyor speeds.
- the recording means is arranged to be programmable by feeding into it data giving the length of the oven with which the apparatus is to be used and the time taken for the apparatus to be conveyed through the oven.
- the recording means is a microcontroller comprising a microprocessor, RAM and an EPROM.
- the invention also provides a method of measuring the longitudinal heat flux profile in a tunnel oven, which comprises adjusting the delay in apparatus according to the invention in accordance with the speed at which material to be heated is conveyed through the oven, causing the apparatus to be conveyed through the oven and downloading the data recorded by the apparatus to a computer.
- Fig. 2 is a plan view, on a larger scale than Fig. 1 , of a part of the apparatus ;
- the sensors 6a and 6b are mounted on raised portions 7a and 7b, respectively, of the block 7 (see Fig. 3).
- the raised portions 7a and 7b are rectangular as seen in plan and they are of the same width as the sensors 6a and 6b.
- the mounting of the sensors 6a and 6b on raised portions of the block 7, and the fact that there is a significant horizontal separation between the raised portions 7a and 7b provides good thermal separation between the sensors.
- the block 7 is supported on, and surrounded by, a mass of a thermally insulating material 8.
- thermocouple junction 13a or 13b Each of the sensors 6a and 6b has associated with it a thermocouple junction 13a or 13b, respectively, from which a flexible pair of leads 14a or 14b runs, respectively, through a bore 15a or 15b, respectively, in the block 7 to the underside of the block 7.
- the thermocouple measurement junctions 13a and 13b permit measurement of the gas temperature a short distance above the upper surface of the associated sensors 6a and 6b, respectively. Because of the flexibility of the pairs of leads 14a and 14b, the precise positions of the thermocouple junctions 13a and 13b, respectively, can readily be adjusted.
- a part 16 of the underside of the casing 1 (see Figs. 1 and 4) is hinged to the remainder of the casing at 17 and is releasably secured in its closed position by means of two pairs of flanges 18, each of which has (see Fig. 6) a threaded aperture for engagement by a closure screw 19 when, in the closed position of the part 15, the flanges of each pair are adjacent to each other.
- the part 16 is in its open position.
- a removable panel (which is held in position by screws) is provided in the underside of the case l. The removable panel is not shown and Fig. 4 shows the underside of the casing with the panel removed.
- the channel 21 runs from the lower ends of the bores 15a and 15b to the rear edge of the underside of the block and affords a passage for the pairs of leads 14a and 14b from the thermocouple measurement junctions 13a and 13b that are provided to measure the gas temperatures above the upper surfaces of the sensors 6a and 6b, respectively.
- the body of the screw clamp terminal 23 is made of a plastics material that combines relatively high thermal conductivity with sufficiently high electrical resistivity to ensure substantially complete electrical insulation between the individual terminals.
- the screw clamp terminal 23 is surrounded on three sides by an aluminium heat sink 24, which ensures a high degree of temperature uniformity as between the individual terminals. Further, a thermistor is provided at 25 to give a signal indicative of the temperature of the aluminium heat sink 24.
- the metals of which the electrically conducting parts of the plugs 26a and 26b are made are the same as those of which the individual leads of the pairs of leads 14a and 14b are made, and the same is true of the electrically conducting parts of the associated sockets (not shown) and of the leads from the sockets to the screw clamp terminal 23. Further, the arrangement is such that the use of the plug-and-socket connectors does not result in the introduction of further, unwanted thermocouple junctions. Then, so far as thermoelectric effects are concerned, the leads from the sockets to the screw clamp terminal 23 can be regarded as mere extensions of the individual leads of the pairs of leads 14a and 14b.
- thermocouple measurement junctions 13a and 13b which are used to measure the gas temperature, are situated above the upper surfaces of the sensors 6a and 6b, they are prone to damage.
- the use of the plugs 26a and 26b, together with the associated sockets (not shown) facilitate replacement of the leads 14a and 14b and hence of thermocouple measurement junctions 13a and 13b as and when required.
- the printed circuit board and its associated circuitry constitute the apparatus for measuring the e.m.f.s generated by the thermocouples (including those in the thermopiles), and the junctions between the conductors on the printed circuit board constitute additional junctions associated with the measuring apparatus and, as required, the arrangement ensures that those junctions are maintained at substantially the same temperature.
- the apparatus is battery-operated, the batteries (which are not shown) being housed within the interior of the casing 1.
- the corresponding digital signals emanating from the analogue-to-digital converter 27 are passed to a recording means in the form of a microcontroller 28 (see Fig. 5), which includes a microprocessor, an EPROM and RAM.
- the program together with basic numerical data, are stored in the EPROM.
- the RAM is used by the program, and it also serves to store the data acquired by the apparatus during a passage of the apparatus through the oven. After the apparatus has passed through the oven, the data that has been acquired during the passage and stored in the RAM is downloaded to a computer.
- the data is recorded periodically at intervals of 0.25 sec, that is to say, at a frequency of 4 sec -1 . If that frequency is not high enough, it will be found that the results obtained are not repeatable.
- the gas within the oven will have a significant velocity, and the conveying of the apparatus through the oven will disturb the gas flow over the apparatus, especially in the vicinity of the leading end 3 of the casing 1 , and therefore in the vicinity of the sensors 6a and 6b.
- Such a disturbance of the gas flow over the sensors 6a and 6b may result in there being a difference between the magnitudes of the convective component of the heat flux incident on the two sensors, even though the comparison between those magnitudes is made, not at the same time, but at the same position of the two sensors. If that occurs, there will be an error in the measurement of the radiative and convective components of the heat flux, and probably also an error in the measurement of the total heat flux.
- the apparatus is provided with a detachable extension, which is indicated generally by the reference numeral 29 (see Fig. 6).
- the extension 29 consists of a rectangular plate 30 and at its rear end a downwardly extending flange 31 formed with apertures to receive bolts 32 for releasably securing the extension to the front of the casing 1.
- the extension 29 When the extension 29 is secured to the casing 1, the upper surface of the rectangular plate 30, which extends over the entire width of the casing 1, is flush with the upper surface of the casing.
- the main disturbance of the gas flow caused by the passage of the apparatus through the oven is in the vicinity of the leading end of the apparatus which, when the extension 29 is not fitted, is in the vicinity of the sensors 6a and 6b.
- the leading end of the apparatus is the leading edge of the plate 30, so that the region of significant disturbance of the gas flow is displaced forwards, away from the sensors 6a and 6b, by a distance equal to the length of the plate.
- the data logged by the microcontroller 28 is downloaded to a computer, and the heat flux profile along the length of the oven, for both the convective component and the radiative component of the heat flux, is obtained.
- the extension 29 is removed by releasing the bolts 32, and the apparatus is so placed on the conveyor that the sides of the casing 1 extend across the width of the oven and the end 3 of the casing is close to the side of the oven.
- the microcontroller 28 is then programmed to record signals from the sensor 6a only, instead of recording signals from both of the sensors 6a and 6b.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Radiation Pyrometers (AREA)
- Investigating Or Analyzing Materials Using Thermal Means (AREA)
- Tunnel Furnaces (AREA)
- Central Heating Systems (AREA)
- Electric Ovens (AREA)
- Fire-Detection Mechanisms (AREA)
- Medicinal Preparation (AREA)
Abstract
Description
Claims
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/242,672 US6264362B1 (en) | 1996-08-28 | 1997-08-07 | Apparatus for and methods of measuring heat flux in a tunnel oven |
AT97935664T ATE254760T1 (en) | 1996-08-28 | 1997-08-07 | ARRANGEMENT FOR MEASURING HEAT FLOW IN OVENS |
JP51134998A JP2001506362A (en) | 1996-08-28 | 1997-08-07 | Measurement of heat flux in ovens and related improvements |
PL97331926A PL331926A1 (en) | 1996-08-28 | 1997-08-07 | Apparatus for measuring heat flow in a tunnel furnace and method of measuring longitudinal heat distribution profile in such furnace |
DE69726287T DE69726287D1 (en) | 1996-08-28 | 1997-08-07 | ARRANGEMENT FOR MEASURING THE HEAT FLOW IN OVENS |
EP97935664A EP0922205B1 (en) | 1996-08-28 | 1997-08-07 | Apparatus for measuring heat flux in ovens |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9617912A GB2317014B (en) | 1996-08-28 | 1996-08-28 | Improvements in and relating to the measurement of heat flux in ovens |
GB9617912.2 | 1996-08-28 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1998009143A1 true WO1998009143A1 (en) | 1998-03-05 |
Family
ID=10799012
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1997/002126 WO1998009143A1 (en) | 1996-08-28 | 1997-08-07 | Improvements in and relating to the measurement of heat flux in ovens |
Country Status (11)
Country | Link |
---|---|
US (1) | US6264362B1 (en) |
EP (1) | EP0922205B1 (en) |
JP (1) | JP2001506362A (en) |
CN (1) | CN1235672A (en) |
AT (1) | ATE254760T1 (en) |
DE (1) | DE69726287D1 (en) |
ES (1) | ES2210553T3 (en) |
GB (1) | GB2317014B (en) |
PL (1) | PL331926A1 (en) |
PT (1) | PT922205E (en) |
WO (1) | WO1998009143A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1195587A1 (en) * | 2000-10-09 | 2002-04-10 | United Biscuits (Uk) Limited | Improvements in and relating to the measurement of heat flux in a heated chamber |
CN101750168B (en) * | 2008-12-19 | 2012-01-04 | 鞍钢集团工程技术有限公司 | Portable multifunctional combined temperature tracker and tracking detection method thereof |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6499357B2 (en) * | 2001-03-13 | 2002-12-31 | Factory Mutual Research Corporation | Heat flux measurement pipe and method for determining sprinkler water delivery requirement |
GB2399175B (en) * | 2003-03-03 | 2006-04-12 | United Biscuits Ltd | Improvements in and relating to the measurement of heat flux in a heated chamber |
US7077563B2 (en) * | 2003-11-19 | 2006-07-18 | General Electric Company | Deposition sensor based on differential heat flux measurement |
RU2521734C2 (en) * | 2009-03-13 | 2014-07-10 | Конинклейке Филипс Электроникс Н.В. | Zero heat flow temperature measurement sensor |
US8517600B2 (en) * | 2009-10-27 | 2013-08-27 | General Electric Company | Deposition sensor based on differential heat transfer resistance |
US8541720B2 (en) * | 2011-04-12 | 2013-09-24 | Raytheon Company | Apparatus for remotely measuring surface temperature using embedded components |
CN102288300B (en) * | 2011-05-10 | 2012-11-07 | 中国科学技术大学 | Radiant heat flux measuring device based on bimaterial micro-cantilever beam |
JP6303973B2 (en) * | 2014-10-20 | 2018-04-04 | 株式会社デンソー | Condition detection sensor |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3779077A (en) * | 1972-04-10 | 1973-12-18 | Siderurgie Fse Inst Rech | Method and apparatus for establishing the firing temperature curve of a sintering charge |
GB2183346A (en) * | 1985-11-20 | 1987-06-03 | United Biscuits Ltd | Measurement of thermal conditions |
GB2265460A (en) * | 1992-03-28 | 1993-09-29 | Univ York | Measuring thermal characteristics of food freezing tunnels and cold stores |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3123996A (en) | 1964-03-10 | musial | ||
US3232113A (en) * | 1961-10-02 | 1966-02-01 | Boeing Co | Thermal parameter indicator |
GB986031A (en) | 1963-02-04 | 1965-03-17 | Boeing Co | Thermal measuring apparatus |
DE2618349A1 (en) * | 1976-04-27 | 1977-11-10 | Weber Guenther | Conduction or convection heat flow measuring transducer - uses defined planar temp. dependent and reference resistances connected in bridge configuration |
-
1996
- 1996-08-28 GB GB9617912A patent/GB2317014B/en not_active Expired - Fee Related
-
1997
- 1997-08-07 PL PL97331926A patent/PL331926A1/en unknown
- 1997-08-07 WO PCT/GB1997/002126 patent/WO1998009143A1/en active IP Right Grant
- 1997-08-07 EP EP97935664A patent/EP0922205B1/en not_active Expired - Lifetime
- 1997-08-07 AT AT97935664T patent/ATE254760T1/en not_active IP Right Cessation
- 1997-08-07 PT PT97935664T patent/PT922205E/en unknown
- 1997-08-07 ES ES97935664T patent/ES2210553T3/en not_active Expired - Lifetime
- 1997-08-07 CN CN97199258.4A patent/CN1235672A/en active Pending
- 1997-08-07 US US09/242,672 patent/US6264362B1/en not_active Expired - Lifetime
- 1997-08-07 JP JP51134998A patent/JP2001506362A/en active Pending
- 1997-08-07 DE DE69726287T patent/DE69726287D1/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3779077A (en) * | 1972-04-10 | 1973-12-18 | Siderurgie Fse Inst Rech | Method and apparatus for establishing the firing temperature curve of a sintering charge |
GB2183346A (en) * | 1985-11-20 | 1987-06-03 | United Biscuits Ltd | Measurement of thermal conditions |
GB2265460A (en) * | 1992-03-28 | 1993-09-29 | Univ York | Measuring thermal characteristics of food freezing tunnels and cold stores |
Non-Patent Citations (1)
Title |
---|
"OPTICAL TEMPERATURE PROFILING OF BELT OVENS", IBM TECHNICAL DISCLOSURE BULLETIN, vol. 34, no. 11, 1 April 1992 (1992-04-01), pages 371 - 372, XP000303296 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1195587A1 (en) * | 2000-10-09 | 2002-04-10 | United Biscuits (Uk) Limited | Improvements in and relating to the measurement of heat flux in a heated chamber |
US6536945B2 (en) | 2000-10-09 | 2003-03-25 | United Biscuits (Uk) Limited | Measurement of heat flux in a heated chamber |
CN101750168B (en) * | 2008-12-19 | 2012-01-04 | 鞍钢集团工程技术有限公司 | Portable multifunctional combined temperature tracker and tracking detection method thereof |
Also Published As
Publication number | Publication date |
---|---|
ATE254760T1 (en) | 2003-12-15 |
PT922205E (en) | 2004-04-30 |
EP0922205B1 (en) | 2003-11-19 |
CN1235672A (en) | 1999-11-17 |
JP2001506362A (en) | 2001-05-15 |
ES2210553T3 (en) | 2004-07-01 |
GB9617912D0 (en) | 1996-10-09 |
PL331926A1 (en) | 1999-08-16 |
GB2317014B (en) | 2000-06-28 |
US6264362B1 (en) | 2001-07-24 |
EP0922205A1 (en) | 1999-06-16 |
GB2317014A (en) | 1998-03-11 |
DE69726287D1 (en) | 2003-12-24 |
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