EP0398105A2 - Four tunnel - Google Patents

Four tunnel Download PDF

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Publication number
EP0398105A2
EP0398105A2 EP90108507A EP90108507A EP0398105A2 EP 0398105 A2 EP0398105 A2 EP 0398105A2 EP 90108507 A EP90108507 A EP 90108507A EP 90108507 A EP90108507 A EP 90108507A EP 0398105 A2 EP0398105 A2 EP 0398105A2
Authority
EP
European Patent Office
Prior art keywords
height
workpieces
furnace
door
workpiece
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.)
Withdrawn
Application number
EP90108507A
Other languages
German (de)
English (en)
Other versions
EP0398105A3 (fr
Inventor
Helmut Schachinger
Peter Karojet
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.)
Mahler Dienstleistungs GmbH Loeten Haerten Anlagenbau
Original Assignee
Mahler Dienstleistungs GmbH Loeten Haerten Anlagenbau
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 Mahler Dienstleistungs GmbH Loeten Haerten Anlagenbau filed Critical Mahler Dienstleistungs GmbH Loeten Haerten Anlagenbau
Publication of EP0398105A2 publication Critical patent/EP0398105A2/fr
Publication of EP0398105A3 publication Critical patent/EP0398105A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C21D1/767—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material with forced gas circulation; Reheating thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/04—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity adapted for treating the charge in vacuum or special atmosphere
    • F27B9/045—Furnaces with controlled atmosphere
    • F27B9/047—Furnaces with controlled atmosphere the atmosphere consisting of protective gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/14—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment
    • F27B9/20—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path
    • F27B9/24—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path being carried by a conveyor
    • F27B9/243—Endless-strand conveyor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/30—Details, accessories or equipment specially adapted for furnaces of these types
    • F27B9/38—Arrangements of devices for charging
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/30—Details, accessories or equipment specially adapted for furnaces of these types
    • F27B9/40—Arrangements of controlling or monitoring devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D19/00—Arrangements of controlling devices
    • F27D2019/0003—Monitoring the temperature or a characteristic of the charge and using it as a controlling value
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D19/00—Arrangements of controlling devices
    • F27D2019/0028—Regulation
    • F27D2019/0068—Regulation involving a measured inflow of a particular gas in the enclosure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D19/00—Arrangements of controlling devices
    • F27D2019/0084—Controlling closure systems, e.g. doors

Definitions

  • the invention relates to a continuous furnace for the heat treatment of workpieces under a continuously supplied protective gas, which exits at the workpiece inlet opening and at the workpiece outlet opening of the furnace, with a conveying device for transporting the workpieces through the furnace and with movable doors at the workpiece inlet opening or at the workpiece outlet opening.
  • Typical heat treatments are hard and high temperature soldering, aluminum soldering, melting, annealing, hardening, tempering, molding or the like.
  • the protective gas continuously supplied to the furnace ensures that no oxidation processes take place on the mostly metallic workpieces during the heat treatment.
  • the protective gas supplied to the furnace exits at the workpiece inlet opening or at the workpiece outlet opening and is usually selected such that it burns off with the atmospheric oxygen. This creates flame curtains in the area of the workpiece inlet opening and the workpiece outlet opening.
  • the flow of the protective gas directed from the interior of the furnace in the direction of the opposite workpiece inlet opening or workpiece outlet opening should ensure that as little or as little atmospheric oxygen as possible enters the furnace. Slidable doors in front of the workpiece inlet opening or the workpiece outlet opening enable these openings to be opened or closed to a greater or lesser extent.
  • the amount of shielding gas to be supplied to the furnace to ensure that no atmospheric oxygen can enter the openings is a function of the size of these openings.
  • the dependency corresponds to a quadratic function, so that when the door height is doubled, more than twice the amount of protective gas must be fed to the furnace.
  • a disadvantage of a continuous furnace of the type mentioned is to ensure in any case that as far as possible No open oxygen can enter the furnace when the door is open, so that sufficient protective gas is continuously supplied that this condition is met. If the door is not opened, more protective gas is supplied to the furnace than would actually be necessary. Shielding gases, mostly hydrogen, are very expensive, so that an excess supply of shielding gas is uneconomical. Furthermore, when protective gas is burned off in the form of hydrogen, a considerable amount of heat is generated which must be removed from the furnace. This amount of heat, which is usually dissipated via chimneys, is a waste of energy and is therefore uneconomical.
  • the object of the present invention is therefore to remedy this situation and to design a continuous furnace of the type mentioned at the outset such that, depending on the size of the workpieces to be treated, it is in each case under optimal conditions, i.e. can be operated by supplying the just sufficient amount of protective gas.
  • the object is achieved in that means are provided for detecting the height of the workpieces to be introduced into the furnace, and in that means for adjusting the door opening height as a function of the detected height values of the workpieces are provided and that a gas quantity regulator is provided which regulates the protective gas quantity supplied to the furnace as a function of the door opening height.
  • the doors are only opened so far to create an opening height that is just sufficient for the workpieces to enter and exit the furnace.
  • the gas volume controller By controlling the gas volume controller as a function of the door opening height, it is achieved that the protective gas quantity that is necessary at the previously determined opening height is supplied to the furnace in order to produce optimal conditions in the furnace, i.e. ensure that no atmospheric oxygen enters the furnace. The result of this is that only the amount of protective gas required is fed in, which results in an economical mode of operation.
  • the means for detecting the height of the workpieces are connected to a process computer which converts the detected height value into control signals for the means for adjusting the door opening height and at the same time converts it into a control signal for the gas quantity regulator.
  • This structurally particularly simple measure has the advantage that the detected height value is converted into the corresponding control signals via a central processing unit, on the one hand to bring the doors to the optimum height and, at the same time, to control the gas volume regulator into the position in which the corresponding Shielding gas quantity is supplied.
  • the means for detecting the height of the workpieces have a photocell arrangement arranged on the side of the conveying device, which detects the height of the workpieces being transported past them and transmits the measurement signal to the process computer as an electrical pulse.
  • This measure has the advantage that the optical detection of the height of the workpieces means that they cannot be brought into contact with mechanical measuring devices, as a result of which, for example, an applied solder paste could be changed in its position, so that when the solder paste melts, it does not get into the corresponding position Joints could run.
  • Photocell arrangements for example as a diode grid, are structurally simple and robust components. It is also advantageous that the detected height is converted into an electrical pulse, which can be fed directly to the process computer without further conversion measures and can then be processed there accordingly.
  • the process computer keeps the control of the outlet door in the previous position height when the height of the supplied workpieces changes until the workpieces of the previous height have passed the outlet door.
  • This measure has the advantage that when the workpiece height is changed, the inlet door is already adapted to the new conditions, but the outlet door remains in the position until the workpieces of the original workpiece type that have already been accommodated in the furnace pass through it to have. If, for example, a change is made from a small workpiece height to a larger one, the outlet door remains in the low position until the last lower workpiece has left the furnace. This method of operation is used if no influence on the flow characteristics of the protective gas in the furnace is exerted by inlet or outlet doors of different heights.
  • the means for setting the door opening height have a servomotor which can be controlled by the process computer and which moves the door to the corresponding opening height via a linkage.
  • This measure has the advantage that structurally simple and robust means are created to cause the corresponding movement of the doors. It is also possible to retrofit existing ovens by retrofitting these simple means.
  • the process computer contains a function of the shielding gas supply quantity dependence on the door opening height that corresponds to the respective furnace characteristic, and the gas quantity regulator is controlled in accordance with this function.
  • This measure has the advantage that the furnace manufacturer determines the respective furnace characteristics, that is to say the protective gas quantity that is necessary to achieve the optimum protective gas effect at a certain door height.
  • the control of the gas volume regulator then corresponds to this function, so that a respective furnace can be operated under the best economic conditions.
  • a continuous furnace or protective gas furnace 10 shown in FIG. 1 has an endless conveyor belt 12 which can be moved in one direction, as is shown by an arrow 13 in FIG. 1.
  • the conveyor belt 12 is moved by a controllable drive, not shown here, which gives the endless conveyor belt 12 a certain rotational speed.
  • Usual transport speeds are in the range of 100 to 400 mm per minute.
  • the protective gas furnace 10 also has a housing 14 through which the conveyor belt 12 runs, a cooling zone 18 adjoining a heating zone 16 in the direction of passage of the conveyor belt.
  • the housing 14 is provided with a workpiece inlet opening 21 which can be closed or opened by a movable inlet door 20. At the opposite end, the housing is provided with a workpiece outlet opening 23 which can be opened or closed via an appropriately designed outlet door 22.
  • a combustion chamber 24 which is provided with a trigger 26 at the upper end.
  • a combustion chamber 28 is arranged immediately after the outlet door 22, the upper end of which is also provided with a trigger 30.
  • means 32 for detecting the height of workpieces 60 to 62 are arranged, which are conveyed by the conveyor belt 12 in the direction of arrow 13 through the protective gas furnace 10.
  • the means 32 for detecting the height have photocells arranged in the form of a diode grid 34 on the side of the conveyor belt 12. If a workpiece 60, as shown in FIG. 1, is transported past the diode grid 34 by the conveyor belt 12, the height of the workpiece is detected by the fact that those photocells that are covered by the passing workpiece are blocked by a light beam striking them generate corresponding electrical signal, which is fed to a process computer 38 via a line 36.
  • the process computer 38 is connected via a line 40 to a servomotor 42, which in turn is connected to the inlet door 20 via a linkage 44.
  • the diode grid 34 has registered the height "3", whereupon the process computer 38 controls the servomotor in such a way that it also moves the linkage 44 into the position "3".
  • the inlet door 20 is then raised so that a workpiece 61 of height "3" can pass just under the raised inlet door 20.
  • the process computer 38 is also connected via a line 46 to a further servomotor 48 which is connected to the outlet door 22 via a linkage 50.
  • the servomotor 48 is designed in the same way as the servomotor 42 and is also in the position "3", i.e. the outlet door 22 is also raised so far that a workpiece 62 can be transported out of the furnace 10 just below it.
  • the process meter 38 is also connected via a line 52 to a gas quantity regulator 54.
  • the gas quantity regulator 54 regulates the quantity of a protective gas 58 which, coming from a gas supply line 56, as indicated by an arrow 57, is fed via the gas quantity regulator 54 and a gas supply line 59 to the heating zone 16 of the housing 14.
  • the protective gas 58 fed into the heating zone 16 partly flows in the direction of the workpiece inlet opening 21 and exits the housing 14 under the opened inlet door 20 and enters the combustion chamber 24.
  • the protective gas namely hydrogen, burns with the atmospheric oxygen and forms a flame curtain, as indicated by the flames 25 in FIG. 1.
  • Another partial flow of the protective gas 58 flows through the cooling zone 18 of the housing 14 in the direction of the workpiece outlet opening 23 and exits from the housing 14 under the opened outlet door 22 and enters the combustion chamber 28. There, too, the hydrogen gas burns off to form a flame curtain 29.
  • the gas quantity regulator 24 is also set to the criterion height “3” and controls the protective gas 58 to the housing 14 as much as is necessary so that no atmospheric oxygen can enter the housing 14.
  • the function shown in FIG. 2 is characteristic of a particular type of furnace, with the clear passage width and clear passage height being incorporated.
  • the dependence on shielding gas quantity SG and door height HT shown in FIG. 2 is stored in the process computer 38, so that the shielding gas quantity regulator 54 regulates the shielding gas quantity 58 supplied in accordance with this characteristic shown in FIG. 2.
  • the heating and circulating devices naturally present in the furnace are not shown for the sake of clarity.
  • the inlet door 20 is raised accordingly.
  • Appropriate programming of the process computer 38 can then be used in such a way that the outlet door 22 is also raised at the same time. This is usually desirable because evenly lifting the inlet and outlet doors 20 and 22 does not significantly change the flow characteristics in the furnace.
  • the control of the outlet door 22 must of course be such that it remains at the height "3" until the last of the high workpieces, that is the workpiece 60 has left the furnace. Then the outlet door 22 is then also set to the lower height of the subsequent workpieces, ie lowered.
  • the inlet door 20 immediately after the first lower workpiece, the diode grid 34 has passed, or only after the last higher workpiece has passed the outlet door 22.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Metallurgy (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Organic Chemistry (AREA)
  • Tunnel Furnaces (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)
  • Furnace Details (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
EP19900108507 1989-05-18 1990-05-07 Four tunnel Withdrawn EP0398105A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3916178 1989-05-18
DE19893916178 DE3916178C1 (fr) 1989-05-18 1989-05-18

Publications (2)

Publication Number Publication Date
EP0398105A2 true EP0398105A2 (fr) 1990-11-22
EP0398105A3 EP0398105A3 (fr) 1991-06-26

Family

ID=6380880

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900108507 Withdrawn EP0398105A3 (fr) 1989-05-18 1990-05-07 Four tunnel

Country Status (3)

Country Link
EP (1) EP0398105A3 (fr)
JP (1) JPH02309182A (fr)
DE (1) DE3916178C1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992011544A1 (fr) * 1990-12-20 1992-07-09 Nomafa Ab Dispositif de commande automatique d'une porte
GB2448501A (en) * 2007-04-17 2008-10-22 Redford Design Ltd Aperture cover assembly for a tunnel oven
CN116868020A (zh) * 2021-02-02 2023-10-10 雷姆热系统有限责任公司 用于在电子组件制造中执行热处理的处理室的机电门帘
CN121402738A (zh) * 2025-12-30 2026-01-27 四川科跃热传电子有限公司 一种连续式高温钎焊炉

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE9014009U1 (de) * 1990-07-04 1991-08-08 Air Products GmbH, 4320 Hattingen Vorrichtung zur Brennerabgasnutzung zum Glühen von Werkstücken aus NE-Metallen in Blankglühöfen
DE4104982A1 (de) * 1991-02-19 1992-08-20 Linde Ag Durchlaufwaermebehandlungsanlage mit spezieller schutzgasabsaugung
DE102005016632B3 (de) * 2005-01-26 2006-08-10 Smiths Heimann Gmbh Strahlenschutztor
US20080271653A1 (en) * 2006-10-12 2008-11-06 Mircea Stefan Stanescu Controlling curtain opening system in continuous furnaces
DE102007029302A1 (de) 2007-06-22 2009-01-02 Behr Gmbh & Co. Kg Durchlaufofen
EP2813584A1 (fr) * 2013-06-11 2014-12-17 Linde Aktiengesellschaft Système et procédé de trempe d'un objet métallique chauffé
DE102014116464A1 (de) * 2014-11-11 2016-05-12 Dieffenbacher GmbH Maschinen- und Anlagenbau Einhausung für eine Produktionsvorrichtung, Verfahren zum Betreiben einer derartigen Einhausung und Materialschleusenvorrichtung für eine derartige Einhausung
EP3991856A1 (fr) * 2020-11-02 2022-05-04 Cefla Societa' Cooperativa Four pour le séchage aux uv en atmosphère inerte

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2601658C3 (de) * 1976-01-17 1978-11-30 Fa. J.F. Mahler, 7300 Esslingen Kühlvorrichtung für einen an der Ein- und Auslaßseite offenen Durchlaufofen zum Wärmebehandeln von Werkstücken
DE2737615C2 (de) * 1977-08-20 1983-10-06 Fa. J. Aichelin, 7015 Korntal Durchlaufofen für Schutzgasbetrieb
JPS58181819A (ja) * 1982-04-14 1983-10-24 Kawasaki Steel Corp ウオ−キングビ−ム式加熱炉における装入口扉の開度制御方法
US4449922A (en) * 1982-08-30 1984-05-22 Bloom Engineering Company, Inc. Reheat furnace drop out door seal
GB2135032B (en) * 1983-02-10 1986-09-24 Boc Group Plc Heat treatment of workpieces
GB8303673D0 (en) * 1983-02-10 1983-03-16 Boc Group Plc Heat treatment of workpieces

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992011544A1 (fr) * 1990-12-20 1992-07-09 Nomafa Ab Dispositif de commande automatique d'une porte
GB2448501A (en) * 2007-04-17 2008-10-22 Redford Design Ltd Aperture cover assembly for a tunnel oven
CN116868020A (zh) * 2021-02-02 2023-10-10 雷姆热系统有限责任公司 用于在电子组件制造中执行热处理的处理室的机电门帘
CN121402738A (zh) * 2025-12-30 2026-01-27 四川科跃热传电子有限公司 一种连续式高温钎焊炉

Also Published As

Publication number Publication date
JPH02309182A (ja) 1990-12-25
DE3916178C1 (fr) 1990-06-13
EP0398105A3 (fr) 1991-06-26

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