EP0188659B1 - Industrial furnace for the continuous heat treatment of articles - Google Patents

Industrial furnace for the continuous heat treatment of articles Download PDF

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Publication number
EP0188659B1
EP0188659B1 EP85111008A EP85111008A EP0188659B1 EP 0188659 B1 EP0188659 B1 EP 0188659B1 EP 85111008 A EP85111008 A EP 85111008A EP 85111008 A EP85111008 A EP 85111008A EP 0188659 B1 EP0188659 B1 EP 0188659B1
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EP
European Patent Office
Prior art keywords
conveyor belt
heat
industrial furnace
rollers
run
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 - Lifetime
Application number
EP85111008A
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German (de)
French (fr)
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EP0188659A2 (en
EP0188659A3 (en
Inventor
Reinhold Bayer
Gerhard Dreizler
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Aichelin GmbH Germany
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Aichelin GmbH Germany
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Priority to AT85111008T priority Critical patent/ATE58964T1/en
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Publication of EP0188659A3 publication Critical patent/EP0188659A3/en
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Classifications

    • 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 tunnel furnace
    • 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 tunnel furnace 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 peculiar to 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
    • F27B9/14—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 tunnel furnace
    • 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 tunnel furnace being carried by a conveyor
    • F27B9/243—Endless-strand conveyor
    • F27B2009/2438—Endless-strand conveyor with means to transfer the heat from the outcoming band to the incoming band
    • 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 peculiar to furnaces of these types
    • F27B9/36—Arrangements of heating devices
    • F27B2009/3638—Heaters located above and under the track
    • 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
    • F27B9/06—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated
    • F27B9/068—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated heated by radiant tubes, the tube being heated by a hot medium, e.g. hot gases
    • 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
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/12—Travelling or movable supports or containers for the charge
    • F27D2003/121—Band, belt or mesh
    • 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
    • F27D21/00—Arrangements of monitoring devices; Arrangements of safety devices
    • F27D2021/0007—Monitoring the pressure
    • 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
    • F27D21/00—Arrangements of monitoring devices; Arrangements of safety devices
    • F27D21/0014—Devices for monitoring temperature

Definitions

  • the invention is based on an industrial furnace for the heat treatment of workpieces passing through.
  • Such an industrial furnace has significant advantages in terms of thermal energy balance compared to industrial furnaces in which the empty run exits at the chute. Because the empty run inside the furnace chamber is returned to the loading opening, the temperature of the empty run remains at the process temperature and the thermal energy in the empty run is used specifically to heat the working run, whereby it cools down to temperatures that preclude premature wear of the drive device . The heat released during cooling is immediately absorbed by the workspace and not unnecessarily radiated into the environment. Without additional external energy supply, the temperature of the working area is raised significantly in the direction of the process temperature.
  • the heat transfer device provided between the empty run and the work run in the form of the cylindrical rollers creates a thermal bridge between the runs, so that the runs are coupled to one another in a heat-conducting manner over the entire width.
  • the pressure device for the empty run can either be formed by an essentially flat slideway or a plurality of pressure rollers mounted axially parallel to the heat transfer rollers.
  • the former embodiment has the advantage of being somewhat easier to manufacture, while the second embodiment requires lower driving forces for the conveyor belt.
  • either the pressure rollers or the heat-transferring rollers are each mounted in an associated slide guide, so that a respective roller is guided so as to be longitudinally displaceable in the direction of the slideway or the heat-transferring roller.
  • the heat loss through the conveyor belt can be further reduced if a prechamber connected to the furnace chamber via the loading opening is connected to the furnace chamber, through which the conveyor belt runs and in which at least the heat transfer device and possibly the drive device are located, the prechamber being a filling opening for entering the workpieces.
  • the prechamber Apart from the better thermal insulation, the prechamber largely prevents air from being carried into the furnace atmosphere and thus an impermissible change in its composition.
  • the empty run of the conveyor belt running out of the furnace chamber namely constantly transports the furnace atmosphere into the prechamber, which is flushed with the furnace atmosphere in this way. Any external air that may enter the workpieces can be flushed out of the entrained furnace gases via the filler opening.
  • the water siphon required in the prior art is therefore not required.
  • the filling opening is arranged above the conveyor belt and, viewed in the conveying direction, in front of the heat transfer device. In this way, the entire length of the heat transfer device is used to transfer heat from the empty run to the work run and the workpieces.
  • the feed opening which is particularly critical with regard to the loss of furnace gases, can be reduced in its internal width if a deflection device for the empty run is arranged within the furnace chamber in the vicinity of the feed opening and raises the empty run towards the underside of the working run.
  • an industrial furnace 1 is illustrated, or the like for the continuous heat treatment of workpieces, for example for carburizing, nitriding, carbonitriding. serves.
  • the industrial furnace 1 contains an elongated, heat-insulating-lined furnace chamber 2, through which heating pipes 3 lead from side wall to side wall, in which burners are used to heat the furnace atmosphere.
  • the furnace chamber 2 contains a loading opening 5, which is adjoined to the outside by a straight antechamber 6, which is tubular and is also heat-insulated.
  • the interior 7 of the pre-chamber 6, which is approximately rectangular in cross section, is aligned with the loading opening 5 and ends at a filling opening 8 opposite the loading opening 5.
  • the industrial furnace 1 For transporting the workpieces from the filling opening 8 through the pre-chamber 6 and the furnace chamber 2 to the chute 11, the industrial furnace 1 contains an endless heat-resistant conveyor belt 12 which can be set in motion by means of a drive device 13 upstream of the pre-chamber 6.
  • the run of the conveyor belt 12 emerging from the drive device 13 forms the working run 14, which enters through the filling opening 8 into the interior 7 of the prechamber 6, runs there via a heat transfer device 15 described below and finally through the loading opening 5 into the interior of the furnace chamber 2 arrives.
  • the working run which runs constantly horizontally from the drive device 13, is supported by a stove 10, which is shown in detail in cross section in FIG. 4.
  • a deflection device 16 for the conveyor belt 12 is arranged in the interior of the furnace chamber 2, which is formed by a cylindrical roller which can freely rotate inside the furnace chamber 2; the width of the roller corresponds to the width of the conveyor belt 12 used in each case.
  • the conveyor belt 12 is deflected in this direction above the opening of the chute 11 located in the interior of the furnace chamber 2 by approximately 180 ° back towards the drive device 13; Objects brought in from the working section 14 fall into the chute 11 and thus leave the furnace chamber 2.
  • the section of the conveyor belt 12 now running back below the working section 14 and referred to as an empty section 17 runs through the interior of the furnace chamber 2 back to the loading opening 5, one in the vicinity of the loading opening 5 rotatably arranged roller 18 raises the empty sag 17 freely sagging inside the furnace chamber 2 near the underside of the working strand 15, so that the loading opening 5, through which the empty strand 17 emerges again from the furnace chamber 2, only a small one must have clear height.
  • the empty run 17 passes through the heat transfer device 15 located in the prechamber 6 before it enters the drive device 13 at the filling opening 8 from the interior 7 of the prechamber 6.
  • the drive device 13 essentially contains two axially parallel rotatable rollers 19 and 20, of which the roller 19 serves as a tensioning roller for the conveyor belt 12, while the roller 20 is to be set in slow revolutions by a geared motor 21 for the purpose of driving the conveyor belt 12.
  • the above-mentioned stove 10 arranged inside the furnace chamber 2 essentially consists, as shown in FIG. 4, of two parallel rails 25 and 26 running at a distance from one another, which in the exemplary embodiment shown are rigid on a total of four beams 27 running across the furnace chamber 2 are attached. 4, the bars 27 are loosely inserted in corresponding recesses 28 and 29 in the brick lining 31 of the furnace chamber 2.
  • angular rails 25 and 26 are intended to support the working strand 14 of the conveyor belt 12, their distance from one another corresponds to the width of the conveyor belt 12, which is provided with edge-side guide strips 32 and 33 in order to prevent the workpieces from falling off.
  • the heat transfer device 15 is explained below, which is located in the antechamber 6 between the working section 14 and the empty section 17 of the conveyor belt 12.
  • the heat transfer device 15 is used to transfer the heat continuously conveyed out of the furnace chamber 2 with the empty strand 17 to the working strand entering the furnace chamber 2 from the pre-chamber 6, whereby two things are achieved:
  • the empty strand 17 is opened after exiting the furnace chamber handy temperatures cooled so that no particularly heat-resistant devices are required on the part of the drive device 13.
  • the heat that is constantly extracted with the empty run 17 is transferred to the work run 14 transferred, which makes it possible to keep the heat loss from the furnace chamber 2 low.
  • the empty run 17 emerging from the loading opening 5 has the temperature of the furnace atmosphere at approximately 800 ° C.
  • the empty strand has cooled down from the above-mentioned 800 ° C. to approx. 60 ° C.
  • the heat released in this process is transferred to the work strand 14 provided with the workpieces, which has a temperature of 40 ° C at the filling opening 8 and is already heated to 600 ° C by the heat transfer device 15 at the loading opening 5.
  • the heat transfer device 15 enables a significant improvement in the heat balance, because the heat emitted by the empty run 17 does not go uselessly into the environment, but can be used to heat the working run 14 and the workpieces.
  • the interior 7 of the prechamber 6 is delimited by a steel tube 41 with a rectangular cross section, which calibrates from the filling opening 8 to the outside of the end wall 4 of the furnace chamber 2 and the floor 42, two parallel side walls 43, 44 and the ceiling 45 of the interior 7 forms.
  • the thermal insulation of the pre-chamber 6 is located outside the steel tube 41, the clear width of which corresponds to the width of the conveyor belt 12.
  • the heat transfer device 15 in the interior of the steel tube 41 is formed by a total of five rollers 46a to 46e which are arranged parallel and at a distance from one another and each consist of a steel tube of corresponding width and can be rotated at right angles to the direction of movement of the conveyor belt 12.
  • the back of the working run 14 and the empty run 17 are held against these steel pipes 46a to 46e, so that a thermal contact or a thermal bridge between the two runs 14, 17 running in the opposite direction is created.
  • the empty run 17 runs over a flat and horizontally running slideway 47 fastened to the floor 42, the width of which is slightly smaller than the distance between the two guide strips 32 and 33 of the conveyor belt 12, as shown in FIG. 3.
  • the slideway 47 extends from the filling opening 8 to the loading opening 5, where it merges into an inclined ramp 48 which extends into the furnace chamber 2.
  • the five heat transfer rollers 46a to 46e which can move freely in height, lie on the upward-facing rear side of the empty run 17 supported by the slide track 47.
  • the working strand 14 runs in the prechamber 6 with its rear side over the outer peripheral surface of the heat transfer rollers 46a to 46e and is held on the outer peripheral surface of the heat transfer rollers 46a to 46e due to gravity.
  • These heat transfer rollers 46a to 46e which are made of heat-conducting and heat-resistant material, have an outside diameter between 10 and 80 mm, but preferably a diameter between 10 and 50 mm and a center distance of about 100 mm from each other, which means that the conveyor belt 12 sags appreciably between two adjacent heat transfer rollers 46a to 46e is avoided.
  • each of the two side walls 43 and 44 contains a rectangular slot 49a to 49e, through which the heat transfer rollers 46a to 46e protrude at the end with a relatively large radial clearance, because their axial length is greater than the clear width of the distance between the two side walls 43 and 44.
  • an angled flange 51, 52 is attached outside of the interior 7 on each of the two side walls 43 and 44, which is only used as a contact surface for the each adjacent end of the heat transfer roller 46a to 46e is used.
  • a swivel flap 54 is suspended in a freely swinging manner above the filling opening 8, which slides along the work strand 14 and is folded up by the workpieces moving with the conveyor belt 12 into the prechamber 6
  • Working strand 14 and the empty strand 17 are still generated with the help of burner nozzles 55, a flame curtain that further seals the interior of the furnace chamber 2 against the outside air.
  • outside air should nevertheless enter the prechamber, it is flushed out by the furnace atmosphere emerging from the prechamber 6 and its filling opening 8, which is particularly easy when the conveyor belt, as shown in FIG. 5, is particularly gas-permeable is. There is then a constant slight purging of the prechamber 6 with the furnace atmosphere, specifically over the entire cross section of the interior 7, which effectively prevents air ingress into the furnace chamber 2.
  • the conveyor belt 12 shown in perspective in FIG. 5 consists of a plurality of flattened wire spirals 56a to 56c running transversely to the longitudinal direction of the conveyor belt, two adjacent wire spirals 56a and 56b or 56b and 56c each using a common, likewise transverse round rod 57a to 57d are connected to each other.
  • Each of the plates 58a and 58d is placed on two adjacent round rods 57a to 57d, so that the scale-like superimposition of the plates 58a to 58d shown in FIG. 5 results in the longitudinal direction of the conveyor belt.
  • the round rods 57a to 57d are each bent in the same direction onto the adjacent round rod 57a to 57d and connected to it by a hook-shaped end.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Tunnel Furnaces (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)
  • General Induction Heating (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
  • Heating, Cooling, Or Curing Plastics Or The Like In General (AREA)
  • Muffle Furnaces And Rotary Kilns (AREA)
  • Furnace Charging Or Discharging (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
  • Heterocyclic Carbon Compounds Containing A Hetero Ring Having Oxygen Or Sulfur (AREA)

Abstract

The furnace (1) includes a furnace chamber (2) which at one end has a charging opening (5) and at the other end a chute (11). Between charging opening (5) and chute (11), there extends an endless conveyor belt (12) which, above the chute (11), is deflected in the direction of the charging opening (5). In order to avoid a constant heat loss through the empty section (17) of the conveyor belt (12) emerging from the furnace chamber, a heat transfer device (15) is provided in the region of the charging opening (5) between the cold working section (14) running in and the hot empty section (17) running out. <IMAGE>

Description

Die Erfindung geht aus von einem Industrieofen zur Wärmebehandlung durchlaufender Werkstücke gemäß dem Oberbegriff des Anspruchs 1.The invention is based on an industrial furnace for the heat treatment of workpieces passing through.

Ein gattungsgemäßer Ofen ist in dem Aufsatz "Kriterien für die optimale Ausführung von Industrieöfen für die Wärmebehandlung von Masschenkleinteilen" in der Zeitschrift "Wärme Gas intemational", Band 33 1984, Heft 9 in Bild 14 veranschaulicht. Wie in der zugehörigen Erläuterung ausgeführt soll die Wärme von dem aus der, Ofenkammer auslaufenden Leertrum auf das mit den kalten Werkstücken beladene und deshalb recht kühle Arbeitstrum übertragen werden, um Heizkosten zum Aufheizen des Arbeitstrums nach dem Eintritt in die Ofenkammer zu sparen. Wie die Figur zeigt, werden deshalb Arbeitsund Leertrum im Bereich zwischen der Transporteinrichtung der Beschickungsöffnung der Ofenkammer dicht aneinander geführt.A generic furnace is illustrated in the article "Criteria for the optimal design of industrial furnaces for the heat treatment of small mass particles" in the magazine "Wärme Gas international", volume 33 1984, volume 9 in Fig. 14. As explained in the accompanying explanation, the heat is to be transferred from the empty run that runs out of the furnace chamber to the work section that is loaded with the cold workpieces and is therefore quite cool, in order to save heating costs for heating the work section after entering the furnace chamber. As the figure shows, the working and empty runs are therefore guided close together in the area between the transport device of the loading opening of the furnace chamber.

Ein solcher Industrieofen hat gegenüber Industrieöfen, bei denen das Leertrum am Fallschacht austritt, erhebliche Vorteile hinsichtlich der Wärmeenergiebilanz. Weil nämlich das Leertrum innerhalb der Ofenkammer zur Beschickungsöffnung zurückgeführt wird, bleibt die Temperatur des Leertrums auf Prozeßtemperatur und die in dem Leertrum steckende Wärmeenergie wird gezielt dazu ausqenutzt, das Arbeitstrum aufzuheizen, wobei es sich selber auf Temperaturen abkühlt, die einen vorzeitigen Verschleiß der Antriebseinrichtung ausschließen. Die bei der Abkühlung frei werdende Wärme wird dabei unmittelbar vom Arbeitstrum aufgenommen und nicht unnötig in die Umgebung abgestrahlt. Ohne zusätzliche äußere Energiezufuhr wird so die Temperatur des Arbeitstrums deutlich in Richtung auf die Prozeßtemperatur angehoben.Such an industrial furnace has significant advantages in terms of thermal energy balance compared to industrial furnaces in which the empty run exits at the chute. Because the empty run inside the furnace chamber is returned to the loading opening, the temperature of the empty run remains at the process temperature and the thermal energy in the empty run is used specifically to heat the working run, whereby it cools down to temperatures that preclude premature wear of the drive device . The heat released during cooling is immediately absorbed by the workspace and not unnecessarily radiated into the environment. Without additional external energy supply, the temperature of the working area is raised significantly in the direction of the process temperature.

Mit dem bekannten Industrieofen kann von dem Leertrum auf das Arbeitstrum allerdings nur so viel Wärmeenergie übertragen werden, wie dies durch Strahlung und Wärmeleitung der umgebenden Führungseinrichtungen für das Förderband möglich ist.With the known industrial furnace, however, only as much heat energy can be transferred from the empty run to the work run as is possible by radiation and heat conduction of the surrounding guide devices for the conveyor belt.

Ausgehend hiervon ist es Aufgabe der Erfindung, den gattungsgemäßen Industrieofen derart weiterzubilden, daß bei gleicher Wärmeübertragungsstrecke mehr Wärmeenergie von dem Leertrum auf das Arbeitstrum übertragen werden kann.Proceeding from this, it is an object of the invention to further develop the generic industrial furnace in such a way that more thermal energy can be transferred from the empty strand to the working strand with the same heat transmission path.

Erfindungsgemäß wird diese Aufgabe durch einen Industrieofen mit den Merkmalen des Hauptanspruches gelöst.According to the invention, this object is achieved by an industrial furnace with the features of the main claim.

Die zwischen dem Leertrum und dem Arbeitstrum vorgesehene Wärmeübertragungsvorrichtung in Gestalt der zylindrischen Rollen erzeugt eine Wärmebrücke zwischen den Trums, so daß die Trums über die gesamte Breite wärmeleitend miteinander gekoppelt sind. Andererseits entsteht durch die Rollen praktisch keine zusätzliche Reibung, die durch das Förderband überwunden werden muß, da zwischen den wärmeübertragenden Rollen und den Rückseiten von Arbeitstrum und Leertrum nur Wälzbewegungen auftreten.The heat transfer device provided between the empty run and the work run in the form of the cylindrical rollers creates a thermal bridge between the runs, so that the runs are coupled to one another in a heat-conducting manner over the entire width. On the other hand, there is practically no additional friction due to the rollers, which has to be overcome by the conveyor belt, since only rolling movements occur between the heat-transferring rollers and the rear sides of the working section and empty section.

Die Andruckeinrichtung für das Leertrum kann entweder von einer im wesentlichen ebenen Gleitbahn oder einer Vielzahl von zu den Wärmeübertragungsrollen achsparallel gelagerten Andruckrollen gebildet sein. Die erstgenannte Ausführungsform hat den Vorteil, etwas einfacher in der Herstellung zu sein, während das zweite Ausführungsbeispiel geringere Antriebskräfte für das Förderband erfordert. Je nach Ausführungsform sind entweder jeweils die Andruckrollen oder die wärmeübertragenden Rollen in einer zugehörigen Schieberführung gelagert, damit eine jeweilige Rolle in Richtung auf die Gleitbahn bzw. die wärmeübertragende Rolle längsverschieblich geführt ist.The pressure device for the empty run can either be formed by an essentially flat slideway or a plurality of pressure rollers mounted axially parallel to the heat transfer rollers. The former embodiment has the advantage of being somewhat easier to manufacture, while the second embodiment requires lower driving forces for the conveyor belt. Depending on the embodiment, either the pressure rollers or the heat-transferring rollers are each mounted in an associated slide guide, so that a respective roller is guided so as to be longitudinally displaceable in the direction of the slideway or the heat-transferring roller.

Der Wärmeverlust durch das Förderband kann weiter verringert werden, wenn an die Ofenkammer eine mit dieser über die Beschickungsöffnung in Verbindung stehende Vorkammer angeschlossen ist, durch die das Förderband verläuft und in der sich zumindest die Wärmeübertragungseinrichtung und gegebenenfalls die Antriebseinrichtung befindet, wobei die Vorkammer eine Einfüllöffnung zum Eingeben der Werkstücke aufweist.The heat loss through the conveyor belt can be further reduced if a prechamber connected to the furnace chamber via the loading opening is connected to the furnace chamber, through which the conveyor belt runs and in which at least the heat transfer device and possibly the drive device are located, the prechamber being a filling opening for entering the workpieces.

Abgesehen von der besseren Wärmeisolation verhindert die Vorkammer weitgehend ein Einschleppen von Luft in die Ofenatmosphäre und damit eine unzulässige Änderung von deren Zusammensetzung. Das aus der Ofenkammer auslaufende Leertrum des Förderbandes transportiert nämlich ständig Ofenatmosphäre in die Vorkammer, die auf diese Weise mit Ofenatmosphäre gespült wird. Mit den Werkstücken eventuell eintretende Fremdluft kann auf diese Weise von den mitgerissenen Ofengasen über die Einfüllöffnung herausgespült werden. Der beim Stand der Technik erforderliche Wassersyphon wird deshalb nicht benötigt.Apart from the better thermal insulation, the prechamber largely prevents air from being carried into the furnace atmosphere and thus an impermissible change in its composition. The empty run of the conveyor belt running out of the furnace chamber namely constantly transports the furnace atmosphere into the prechamber, which is flushed with the furnace atmosphere in this way. Any external air that may enter the workpieces can be flushed out of the entrained furnace gases via the filler opening. The water siphon required in the prior art is therefore not required.

Weil obendrein Arbeitstrum und Leertrum durch die Beschickungsöffnung laufen, ist auch der Verlust an Ofenatmosphäre insgesamt geringer als beim Stand der Technik.Because the work run and empty run run through the loading opening on top of that, the loss of furnace atmosphere is also lower overall than in the prior art.

Besonders vorteilhaft ist es, wenn die Einfüllöffnung oberhalb des Transportbandes und, in Förderrichtung gesehen, vor der Wärmeübertragungseinrichtung angeordnet ist. Es wird nämlich auf diese Weise die gesamte Länge der Wärmeübertragungseinrichtung ausgenutzt, um Wärme vom Leertrum auf das Arbeitstrum und die Werkstücke zu übertragen.It is particularly advantageous if the filling opening is arranged above the conveyor belt and, viewed in the conveying direction, in front of the heat transfer device. In this way, the entire length of the heat transfer device is used to transfer heat from the empty run to the work run and the workpieces.

Die hinsichtlich des Verlustes von Ofengasen besonders kritische Beschickungsöffnung kann in ihrer lichten Weite verringert werden, wenn innerhalb der Ofenkammer in der Nähe der Beschikkungsöffnung eine Umlenkeinrichtung für das Leertrum angeordnet ist, die das Leertrum in Richtung auf die Unterseite des Arbeitstrums anhebt.The feed opening, which is particularly critical with regard to the loss of furnace gases, can be reduced in its internal width if a deflection device for the empty run is arranged within the furnace chamber in the vicinity of the feed opening and raises the empty run towards the underside of the working run.

In der Zeichnung ist ein Ausführungsbeispiel des Gegenstandes der Erfindung dargestellt. Es zeigen:

  • Fig. 1 einen Industrieofen gemäß der Erfindung in einem Längsschnitt,
  • Fig. 2 die Vorkammer des Industrieofens nach Fig. 1, ebenfalls im Längsschnitt, jedoch in vergrößertem Maßstab und ohne das durchlaufende Förderband,
  • Fig. 3 die Vorkammer des Industrieofens nach Fig. 1, geschnitten entlang der Linie 111-111 nach Fig. 1,
  • Fig. 4 die Ofenkammer des Industrieofens nach Fig. 1, geschnitten entlang der Linie IV-IV in einem Ausschnitt und
  • Fig. 5 das Förderband des Industrieofens nach Fig. 1 in einer perspektivischen Ausschnittsdarstellung.
In the drawing, an embodiment of the object of the invention is shown. Show it:
  • 1 shows an industrial furnace according to the invention in a longitudinal section,
  • Fig. 2 shows the prechamber of the industrial furnace 1, also in longitudinal section, but on an enlarged scale and without the continuous conveyor belt,
  • 3 shows the prechamber of the industrial furnace according to FIG. 1, cut along the line 111-111 according to FIG. 1,
  • Fig. 4 shows the furnace chamber of the industrial furnace of FIG. 1, cut along the line IV-IV in a section and
  • Fig. 5 shows the conveyor belt of the industrial furnace according to Fig. 1 in a perspective detail.

In Fig. 1 ist ein Industrieofen 1 veranschaulicht, der zum kontinuierlichen Warmbehandeln von Werkstücken, beispielsweise zum Aufkohlen, Nitrieren, Karbonitrieren od.dgl. dient. Der Industrieofen 1 enthält eine längliche wärmeisolierend ausgekleidete Ofenkammer 2, durch die von Seitenwand zu Seitenwand Heizrohre 3 führen, in denen Brenner zum Aufheizen der Ofenatmosphäre stecken. Die Ofenkammer 2 enthält an einer Stirnseite 4 eine Beschickungsöffnung 5, an die sich nach außen eine gerade verlaufende Vorkammer 6 anschließt, die rohrförmig ausgebildet und ebenfalls wärmeisoliert ist. Der im Querschnitt etwa rechteckige Innenraum 7 der Vorkammer 6 fluchtet mit der Beschickungsöffnung 5 und endet an einer der Beschickungsöffnung 5 gegenüberliegenden Einfüllöffnung 8.In Fig. 1, an industrial furnace 1 is illustrated, or the like for the continuous heat treatment of workpieces, for example for carburizing, nitriding, carbonitriding. serves. The industrial furnace 1 contains an elongated, heat-insulating-lined furnace chamber 2, through which heating pipes 3 lead from side wall to side wall, in which burners are used to heat the furnace atmosphere. On one end face 4, the furnace chamber 2 contains a loading opening 5, which is adjoined to the outside by a straight antechamber 6, which is tubular and is also heat-insulated. The interior 7 of the pre-chamber 6, which is approximately rectangular in cross section, is aligned with the loading opening 5 and ends at a filling opening 8 opposite the loading opening 5.

An dem der Stirnwand 4 gegenüberliegenden Ende der Ofenkammer 2 befindet sich in deren Boden 9 ein Fallschacht 11, durch den die durch die Ofenkammer 2 gewanderten Werkstücke den Industrieofen 1 verlassen.At the end of the furnace chamber 2 opposite the end wall 4 there is a chute 11 in the bottom 9 thereof, through which the workpieces which have moved through the furnace chamber 2 leave the industrial furnace 1.

Zum Transport der Werkstücke von der Einfüllöffnung 8 durch die Vorkammer 6 und die Ofenkammer 2 bis hin zum Fallschacht 11 enthält der Industrieofen 1 ein endloses hitzebeständiges Förderband 12, das mittels einer der Vorkammer 6 vorgelagerten Antriebseinrichtung 13 in Bewegung zu setzen ist. Das oben aus der Antriebseinrichtung 13 austretende Trum des Förderbandes 12 bildet das Arbeitstrum 14, das durch die Einfüllöffnung 8 in den Innenraum 7 der Vorkammer 6 eintritt, dort über eine weiter unten beschriebene Wärmeübertragungseinrichtung 15 läuft und schließlich durch die Beschickungsöffnung 5 in den Innenraum der Ofenkammer 2 einläuft. Innerhalb der Ofenkammer 2 ist das von der Antriebseinrichtung 13 ausgehend ständig horizontal verlaufende Arbeitstrum von einem Herd 10 unterstützt, der in Fig. 4 im einzelnen im Querschnitt gezeigt ist. An dem dem Fallschacht 11 benachbarten Ende des Herdes 10 ist im Inneren der Ofenkammer 2 eine Umlenkeinrichtung 16 für das Förderband 12 angeordnet, die von einer im Inneren der Ofenkammer 2 frei drehbaren zylindrischen Rolle gebildet ist; die Breite der Rolle entspricht der Breite des jeweils verwendeten Förderbandes 12. Auf diese Wese wird das Förderband 12 oberhalb der im Inneren der Ofenkammer 2 liegenden Öffnung des Fallschachtes 11 um etwa 180° zurück in Richtung auf die Antriebseinrichtung 13 umgelenkt; vom Arbeitstrum 14 herangeschaffte Gegenstände fallen hier in den Fallschacht 11 und verlassen so die Ofenkammer 2. Der nunmehr unterhalb des Arbeitstrums 14 zurücklaufende und als Leertrum 17 bezeichnete Abschnitt des Förderbandes 12 läuft durch das Innere der Ofenkammer 2 zurück zu der Beschickungsöffnung 5, wobei eine in der Nähe der Beschickungsöffnung 5 drehbar angeordnete Rolle 18 das im Inneren der Ofenkammer 2 frei durchhängende Leertrum 17 in die Nähe der Unterseite des Arbeitstrums 15 anhebt, so daß die Beschickungsöffnung 5, durch die das Leertrum 17 wieder aus der Ofenkammer 2 austritt, nur eine geringe lichte Höhe aufzuweisen braucht. Von der Beschickungsöffnung 5 herkommend durchläuft das Leertrum 17 die in der Vorkammer 6 befindliche Wärmeübertragungseinrichtung 15, ehe es an der Einfüllöffnung 8 aus dem Innenraum 7 der Vorkammer 6 ausund in die Antriebseinrichtung 13 eintritt.For transporting the workpieces from the filling opening 8 through the pre-chamber 6 and the furnace chamber 2 to the chute 11, the industrial furnace 1 contains an endless heat-resistant conveyor belt 12 which can be set in motion by means of a drive device 13 upstream of the pre-chamber 6. The run of the conveyor belt 12 emerging from the drive device 13 forms the working run 14, which enters through the filling opening 8 into the interior 7 of the prechamber 6, runs there via a heat transfer device 15 described below and finally through the loading opening 5 into the interior of the furnace chamber 2 arrives. Within the furnace chamber 2, the working run, which runs constantly horizontally from the drive device 13, is supported by a stove 10, which is shown in detail in cross section in FIG. 4. At the end of the hearth 10 adjacent to the chute 11, a deflection device 16 for the conveyor belt 12 is arranged in the interior of the furnace chamber 2, which is formed by a cylindrical roller which can freely rotate inside the furnace chamber 2; the width of the roller corresponds to the width of the conveyor belt 12 used in each case. The conveyor belt 12 is deflected in this direction above the opening of the chute 11 located in the interior of the furnace chamber 2 by approximately 180 ° back towards the drive device 13; Objects brought in from the working section 14 fall into the chute 11 and thus leave the furnace chamber 2. The section of the conveyor belt 12 now running back below the working section 14 and referred to as an empty section 17 runs through the interior of the furnace chamber 2 back to the loading opening 5, one in the vicinity of the loading opening 5 rotatably arranged roller 18 raises the empty sag 17 freely sagging inside the furnace chamber 2 near the underside of the working strand 15, so that the loading opening 5, through which the empty strand 17 emerges again from the furnace chamber 2, only a small one must have clear height. Coming from the loading opening 5, the empty run 17 passes through the heat transfer device 15 located in the prechamber 6 before it enters the drive device 13 at the filling opening 8 from the interior 7 of the prechamber 6.

Die Antriebseinrichtung 13 enthält im wesentlichen zwei achsparallel gelagerte drehbare Rollen 19 und 20, von denen die Rolle 19 als Spannrolle für das Förderband 12 dient, während die Rolle 20 von einem Getriebemotor 21 zum Zweck des Antriebs des Förderbandes 12 in langsame Umdrehungen zu versetzen ist.The drive device 13 essentially contains two axially parallel rotatable rollers 19 and 20, of which the roller 19 serves as a tensioning roller for the conveyor belt 12, while the roller 20 is to be set in slow revolutions by a geared motor 21 for the purpose of driving the conveyor belt 12.

Der Vollständigket halber sei noch erwähnt, daß unterhalb der Decke der Ofenkammer 2 sich ein motorisch angetriebener Lüfterflügel 22 zum Umwälzen der Ofenatmosphäre befindet, die in ihrer Zusammensetzung und Temperatur mittels einer Partialdrucksonde 23 und eines Thermometers 24 überwacht wird.For the sake of completeness, it should also be mentioned that below the ceiling of the furnace chamber 2 there is a motor-driven fan blade 22 for circulating the furnace atmosphere, the composition and temperature of which are monitored by means of a partial pressure probe 23 and a thermometer 24.

Der oben genannte, innerhalb der Ofenkammer 2 angeordnete Herd 10 besteht im wesentlichen, wie Fig. 4 zeigt, aus zwei parallelen, im Abstand zueinander verlaufenden Schienen 25 und 26, die im gezeigten Ausführungsbeispiel auf insgesamt vier quer durch die Ofenkammer 2 verlaufenden Balken 27 starr befestigt sind. Die Balken 27 stecken, wie sich ebenfalls aus Fig. 4 ergibt, lose in entsprechenden Ausnehmungen 28 und 29 in der Ausmauerung 31 der Ofenkammer 2.The above-mentioned stove 10 arranged inside the furnace chamber 2 essentially consists, as shown in FIG. 4, of two parallel rails 25 and 26 running at a distance from one another, which in the exemplary embodiment shown are rigid on a total of four beams 27 running across the furnace chamber 2 are attached. 4, the bars 27 are loosely inserted in corresponding recesses 28 and 29 in the brick lining 31 of the furnace chamber 2.

Da die winkelförmigen Schienen 25 und 26 das Arbeitstrum 14 des Förderbandes 12 unterstützen sollen, entspricht ihr Abstand voneinander der Breite des Förderbandes 12, das, um ein Herunterfallen der Werkstücke zu verhindern, mit randseitigen Führungsleisten 32 und 33 versehen ist.Since the angular rails 25 and 26 are intended to support the working strand 14 of the conveyor belt 12, their distance from one another corresponds to the width of the conveyor belt 12, which is provided with edge-side guide strips 32 and 33 in order to prevent the workpieces from falling off.

Anhand der Fig. 2 und 3 ist im folgenden die Wärmeübertragungseinrichtung 15 erläutert, die sich in der Vorkammer 6 zwischen dem Arbeitstrum 14 und dem Leertrum 17 des Förderbandes 12 befindet. Die Wärmeübertragungseinrichtung 15 dient dazu, die mit dem Leertrum 17 aus der Ofenkammer 2 ständig herausbeförderte Wärme auf das von der Vorkammer 6 in die Ofenkammer 2 einlaufende Arbeitstrum zu übertragen, womit zwei Dinge erreicht werden: Das Leertrum 17 wird nach dem Austreten aus der Ofenkammer auf handliche Temperaturen abgekühlt, so daß seitens der Antriebseinrichtung 13 keine besonders warmfesten Einrichtungen erforderlich sind. Andererseits wird die ständig mit dem Leertrum 17 herausgeförderte Wärme auf das Arbeitstrum 14 übertragen, was den Wärmeverlust aus der Ofenkammer 2 gering zu halten ermöglicht.2 and 3, the heat transfer device 15 is explained below, which is located in the antechamber 6 between the working section 14 and the empty section 17 of the conveyor belt 12. The heat transfer device 15 is used to transfer the heat continuously conveyed out of the furnace chamber 2 with the empty strand 17 to the working strand entering the furnace chamber 2 from the pre-chamber 6, whereby two things are achieved: The empty strand 17 is opened after exiting the furnace chamber handy temperatures cooled so that no particularly heat-resistant devices are required on the part of the drive device 13. On the other hand, the heat that is constantly extracted with the empty run 17 is transferred to the work run 14 transferred, which makes it possible to keep the heat loss from the furnace chamber 2 low.

So konnten bei einem praktisch ausgeführten Industrieofen folgende Temperaturen an dem Förderband gemessen werden: Das aus der Beschickungsöffnung 5 austretende Leertrum 17 weist die Temperatur der Ofenatmosphäre ca. 800° C auf. Am Ende der Wärmeübertragungseinrichtung 15, d.h. in der Nähe der Einfüllöffnung 8, ist das Leertrum von den erwähnten 800° C auf ca. 60° C heruntergekühlt. Die dabei frei gewordene Wärme ist auf das mit den Werkstücken versehene Arbeitstrum 14 übertragen, das an der Einfüllöffnung 8 eine Temperatur von 40° C aufweist und durch die Wärmeübertragungseinrichtung 15 bei derBeschickungsöffnung 5 bereits auf 600° C aufgeheizt ist.For example, the following temperatures could be measured on the conveyor belt in a practical industrial furnace: The empty run 17 emerging from the loading opening 5 has the temperature of the furnace atmosphere at approximately 800 ° C. At the end of the heat transfer device 15, i.e. near the filling opening 8, the empty strand has cooled down from the above-mentioned 800 ° C. to approx. 60 ° C. The heat released in this process is transferred to the work strand 14 provided with the workpieces, which has a temperature of 40 ° C at the filling opening 8 and is already heated to 600 ° C by the heat transfer device 15 at the loading opening 5.

Ersichtlicherweise ermöglicht die Wärmeübertragungseinrichtung 15 eine deutliche Verbesserung der Wärmebilanz, weil die von dem Leertrum 17 abgegebene Wärme nicht nutzlos in die Umgebung geht, sondern zum Aufheizen des Arbeitstrums 14 und der Werkstücke verwendet werden kann.Obviously, the heat transfer device 15 enables a significant improvement in the heat balance, because the heat emitted by the empty run 17 does not go uselessly into the environment, but can be used to heat the working run 14 and the workpieces.

Bei dem gezeigten Ausführungsbeispiel ist der Innenraum 7 der Vorkammer 6 von einem im Querschnitt rechteckigen Stahlrohr 41 begrenzt, das von der Einfüllöffnung 8 bis zur Außenseite der Stirnwand 4 der Ofenkammer 2 eicht und den Boden 42, zwei Parallel im Abstand verlaufende Seitenwände 43, 44 sowie die Decke 45 des Innenraumes 7 bildet. Die Wärmeisolierung der Vorkammer 6 befindet sich außerhalb des Stahlrohrs 41, dessen lichte Breite der Breite des Förderbandes 12 entspricht.In the exemplary embodiment shown, the interior 7 of the prechamber 6 is delimited by a steel tube 41 with a rectangular cross section, which calibrates from the filling opening 8 to the outside of the end wall 4 of the furnace chamber 2 and the floor 42, two parallel side walls 43, 44 and the ceiling 45 of the interior 7 forms. The thermal insulation of the pre-chamber 6 is located outside the steel tube 41, the clear width of which corresponds to the width of the conveyor belt 12.

Die Wärmeübertragungseinrichtung 15 im Inneren des Stahlrohrs 41 wird von insgesamt fünf parallel im Abstand zueinander angeordneten Rollen 46a bis 46e gebildet, die jeweils aus einem Stahlrohr entsprechender Breite bestehen und rechtwinklig zur Bewegungsrichtung des Transportbandes 12 drehbar sind. An diesen Stahlrohren 46a bis 46e ist jeweils die Rückseite des Arbeitstrums 14 und des Leertrums 17 anliegend gehalten, so daß ein Wärmekontakt oder eine Wärmebrücke zwischen den beiden in entgegengesetzter Richtung laufenden Trums 14, 17 entsteht. Das Leertrum 17 läuft hierzu über eine auf dem Boden 42 befestigte ebene und horizontal verlaufende Gleitbahn 47, deren Breite geringfügig kleiner ist als der Abstand der beiden Führungsleisten 32 und 33 des Förderbandes 12, wie dies Fig. 3 zeigt. Hierdurch wird eine flächige Unterstützung des Leertrums 17, und zwar auf der die Werkstücke aufnehmenden Fläche des Förderbandes 12 erreicht und verhindert, daß das Förderband 12 mit seinen Führungsleisten 32, 33 auf der Gleitbahn 47 aufsteht und damit hohlliegen würde. Die Gleitbahn 47 reicht von der Einfülöffnung 8 bis zu der Beschickungsöffnung 5, wo sie in eine schräge Rampe 48 übergeht, die bis in die Ofenkammer 2 hineinreicht. Auf der nach oben gekehrten Rückseite des von der Gleitbahn 47 unterstützten Leertrums 17 liegen die fünf Wärmeübertragungsrollen 46a bis 46e auf, die sich in der Höhe frei bewegen können. Das Arbeitstrum 14 läuft in der Vorkammer 6 mit seiner Rückseite über die Außenumfangsfläche derwärmeübertragenden Rollen 46a bis 46e und wird aufgrund der Schwerkraft an der Außenumfangsfläche derwärmeübertragenden Rollen 46a bis 46e gehalten. Diese aus wärmeleitendem und warmfestem Material bestehenden Wärmeübertragungsrollen 46a bis 46e haben einen Außendurchmesser zwischen 10 und 80 mm, vorzugsweise jedoch einen Durchmesser zwischen 10 und 50 mm und einen Mittenabstand voneinander von etwa 100 mm, womit ein nennenswertes Durchhängen des Förderbandes 12 zwischen jeweils zwei benachbarten Wärmeübertragungsrollen 46a bis 46e vermieden ist.The heat transfer device 15 in the interior of the steel tube 41 is formed by a total of five rollers 46a to 46e which are arranged parallel and at a distance from one another and each consist of a steel tube of corresponding width and can be rotated at right angles to the direction of movement of the conveyor belt 12. The back of the working run 14 and the empty run 17 are held against these steel pipes 46a to 46e, so that a thermal contact or a thermal bridge between the two runs 14, 17 running in the opposite direction is created. For this purpose, the empty run 17 runs over a flat and horizontally running slideway 47 fastened to the floor 42, the width of which is slightly smaller than the distance between the two guide strips 32 and 33 of the conveyor belt 12, as shown in FIG. 3. This results in a flat support of the empty run 17, namely on the workpiece-receiving surface of the conveyor belt 12, and prevents the conveyor belt 12 with its guide strips 32, 33 from standing on the slideway 47 and thus lying hollow. The slideway 47 extends from the filling opening 8 to the loading opening 5, where it merges into an inclined ramp 48 which extends into the furnace chamber 2. The five heat transfer rollers 46a to 46e, which can move freely in height, lie on the upward-facing rear side of the empty run 17 supported by the slide track 47. The working strand 14 runs in the prechamber 6 with its rear side over the outer peripheral surface of the heat transfer rollers 46a to 46e and is held on the outer peripheral surface of the heat transfer rollers 46a to 46e due to gravity. These heat transfer rollers 46a to 46e, which are made of heat-conducting and heat-resistant material, have an outside diameter between 10 and 80 mm, but preferably a diameter between 10 and 50 mm and a center distance of about 100 mm from each other, which means that the conveyor belt 12 sags appreciably between two adjacent heat transfer rollers 46a to 46e is avoided.

Für jede der Wärmeübertragungsrollen 46a bis 46e enthält jede der beiden Seitenwände 43 und 44 einen rechteckigen Schlitz 49a bis 49e, durch die die wärmeübertragenden Rollen 46a bis 46e endseitig mit verhältnismäßig großem Radialspiel hindurchragen, denn deren axiale Länge ist größer als die lichte Weite des Abstandes zwischen den beiden Seitenwänden 43 und 44. Um ein allmähliches Herauswandern der wärmeübertragenden Rollen 46a bis 46e in axialer Richtung zu vermeiden, ist außerhalb des Innenraumes 7 an jeder der beiden Seitenwände 43 und 44 ein abgewinkelter Flansch 51, 52 befestigt, der lediglich als Anlauffläche für die jeweils benachbarte Stirnseite der wärmeübertragenden Rolle 46a bis 46e dient.For each of the heat transfer rollers 46a to 46e, each of the two side walls 43 and 44 contains a rectangular slot 49a to 49e, through which the heat transfer rollers 46a to 46e protrude at the end with a relatively large radial clearance, because their axial length is greater than the clear width of the distance between the two side walls 43 and 44. To avoid a gradual migration of the heat transfer rollers 46a to 46e in the axial direction, an angled flange 51, 52 is attached outside of the interior 7 on each of the two side walls 43 and 44, which is only used as a contact surface for the each adjacent end of the heat transfer roller 46a to 46e is used.

Wenn, wie nachstehend noch erläutert, die Führungsleisten 32 und 33 des Förderbandes 12 über dessen Rückseite hinausstehen, ist es erforderlich, die wärmeübertragenden Rollen 46a bis 46e in der in Fig. 3 gezeigten Weise endseitig abzusetzen, um zu vermeiden, daß das Förderband mit seinen Leisten 32, 33 auf den wärmeübertragenden Rollen 46a bis 46e aufstehen, wodurch die Rückseite des Förderbandes 12 hohlliegen würde. Wenn fürdie wärmeübertragenden Rollen 46, wie gezeigt, zylindrische Rohre verwendet werden, genügt es, in diese zylindrischen Rohre endseitig zylindrische Rohre 53 mit entsprechend geringerem Durchmesser einzustekken und zu befestigen.If, as will be explained below, the guide strips 32 and 33 of the conveyor belt 12 protrude beyond its rear side, it is necessary to lower the heat-transferring rollers 46a to 46e in the manner shown in FIG. 3 in order to avoid that the conveyor belt with its Last 32, 33 stand on the heat transfer rollers 46a to 46e, whereby the back of the conveyor belt 12 would be hollow. If, as shown, cylindrical tubes are used for the heat-transferring rollers 46, it is sufficient to insert and fasten cylindrical tubes 53 with a correspondingly smaller diameter at the end of these cylindrical tubes.

Um ein Einströmen von Außenluft in die Ofenkammer 2 weitgehend zu vermeiden, ist oberhalb der Einfüllöffnung 8 eine Schwenkklappe 54 frei pendelnd aufgehängt, die auf dem Arbeitstrum 14 entlanggleitet und von den sich mit dem Förderband 12 in die Vorkammer 6 bewegenden Werkstücken hochgeklappt wirdWeiterhin kann zwischen dem Arbeitstrum 14 und dem Leertrum 17 noch mit Hilfe von Brennerdüsen 55 ein Flammvorhang erzeugt werden, der den Innenraum der Ofenkammer 2 weiter gegen die Außenluft abdichtet. Falls dennoch Außenluft in die Vorkammer eindringen sollte, wird sie von aus der Vorkammer 6 und deren Einfüllöffnung 8 austretende Ofenatmosphäre mit herausgespült, was insbesondere dann besonders leicht vonstatten geht, wenn das Förderband, wie in Fig. 5 gezeigt, besonders gasdurchlässig ausgebildet ist. Es erfolgt dann eine ständige geringfügie Spülung der Vorkammer 6 mit Ofenatmosphäre, und zwar über den gesamten Querschnitt des Innenraums 7, was wirksam Lufteinbrüche in die Ofenkammer 2 verhindert.In order to largely prevent outside air from flowing into the furnace chamber 2, a swivel flap 54 is suspended in a freely swinging manner above the filling opening 8, which slides along the work strand 14 and is folded up by the workpieces moving with the conveyor belt 12 into the prechamber 6 Working strand 14 and the empty strand 17 are still generated with the help of burner nozzles 55, a flame curtain that further seals the interior of the furnace chamber 2 against the outside air. If outside air should nevertheless enter the prechamber, it is flushed out by the furnace atmosphere emerging from the prechamber 6 and its filling opening 8, which is particularly easy when the conveyor belt, as shown in FIG. 5, is particularly gas-permeable is. There is then a constant slight purging of the prechamber 6 with the furnace atmosphere, specifically over the entire cross section of the interior 7, which effectively prevents air ingress into the furnace chamber 2.

Das ausschnittsweise in Fig. 5 perspektivisch gezeigte Förderband 12 besteht aus einer Vielzahl von zur Förderbandlängsrichtung quer verlaufenden abgeplatteten Drahtspiralen 56a bis 56c, wobei jeweils zwei benachbarte Drahtspiralen 56a und 56b bzw. 56b und 56c mittels einer ihnen jeweils gemeinsamen, ebenfalls quer verlaufenden Rundstange 57a bis 57d miteinander verbunden sind. An jedem Ende der Drahtspiralen 56a bis 56c steckt auf jeder der Rundstangen 57a bis 57d je zwei Platten 58a bis 58d, die die beiden Führungsleisten 32 und 33 bilden. Dabei steckt jede der Platten 58a und 58d auf jeweils zwei einander benachbarten Rundstangen 57a bis 57d, so daß sich das in Fig. 5 ersichtliche schuppenartige Übereinanderliegen der Platten 58a bis 58d in Transportbandlängsrichtung ergibt.The conveyor belt 12 shown in perspective in FIG. 5 consists of a plurality of flattened wire spirals 56a to 56c running transversely to the longitudinal direction of the conveyor belt, two adjacent wire spirals 56a and 56b or 56b and 56c each using a common, likewise transverse round rod 57a to 57d are connected to each other. At each end of the wire spirals 56a to 56c there are two plates 58a to 58d on each of the round rods 57a to 57d, which form the two guide strips 32 and 33. Each of the plates 58a and 58d is placed on two adjacent round rods 57a to 57d, so that the scale-like superimposition of the plates 58a to 58d shown in FIG. 5 results in the longitudinal direction of the conveyor belt.

Außerhalb der platten 58a bis 58d sind die Rundstangen 57a bis 57d jeweils in gleicher Richtung auf die benachbarte Rundstange 57a bis 57d abgebogen und mit dieser durch ein hakenförmiges Ende verbunden.Outside the plates 58a to 58d, the round rods 57a to 57d are each bent in the same direction onto the adjacent round rod 57a to 57d and connected to it by a hook-shaped end.

Falls die durch die Gleitbahn 47 hervorgerufenen Reibungskräfte zu groß sind, ist es auch möglich, anstelle der durchgehenden Gleitbahn 47 unterhalb jeder der wärmeübertragenden Rollen 46a bis 46e weitere Rollen drehbar zu lagern, so daß zwischen dem Förderband 12 und den Teilen in der Vorkammer 6, die mit dem Förderband 12 in Berührung kommen, lediglich Abwälzbewegungen auftreten.If the frictional forces caused by the slideway 47 are too great, it is also possible, instead of the continuous slideway 47, to rotatably mount further rollers underneath each of the heat-transferring rollers 46a to 46e, so that between the conveyor belt 12 and the parts in the antechamber 6, that come into contact with the conveyor belt 12, only rolling movements occur.

Claims (10)

1. An industrial furnace for the heat treatment of moving workpieces, having: a furnace chamber having a charging aperture at one end and a dropping shaft at the other; an endless conveyor belt which is deflected contrary to the conveying direction of the workpieces in the zone of the dropping shaft and of which both its working run receiving the workpieces and also its empty run pass through the charging opening and extend through the furnace chamber from the charging opening to the dropping shaft; a driving device for the conveyor belt; and a second deflecting device, disposed outside the furnace chamber and adjacent the charging opening, for the conveyor belt, the two runs being guided close one above the other outside the furnace chamber, to transfer heat from the empty run emerging from the charging opening to the working run running into the charging opening, characterized in that a heat transferring device (15) is provided between the two runs in the zone of heat transfer; the heat transferring device is formed by a plurality of cylinder-shaped or cylindrical rollers (46a... 46e) of heat-conducting, heat resistant material which extend over the width of the conveyor belt (12) and which are mounted to pivot at right angles to the direction of movement of the working run (14) and over which the working run (14) passes bearing thereagainst; and the empty run (17) is retained in contact with the peripheral surface of the heat- transferring rollers (46a... 46e) by means of contact pressure devices (47).
2. An industrial furnace according to claim 1, characterized in that the contact pressure device is formed by a substantially flat slideway (47) over which the empty run (17) slides and which supports the empty run (17); and each of the heat transferring rollers (46a ... 46e) can move freely at right angles to the surface formed by the slideway (47).
3. An industrial furnace according to claim 1, characterized in that the contact pressure device is formed by contact pressure rollers mounted axis-parallel with the heat transferring rollers (46a... 46e), and for the bearing of either each contact pressure roller (46a... 46e) or of each of the heat transferring rollers a sliding guide is provided in which each roller is guided vertically longitudinally displaceably in the direction of the other roller.
4. An industrial furnace according to claim 1, characterized in that the furnace chamber is adjoined by an anti-chamber (6) which is connected thereto via the charging aperture (5) and through which the conveyor belt (12) extends and in which at least a portion of the heat transferring device (15) is disposed, and the anti-chamber (6) has a filling aperture (8) for the introduction of the workpieces.
5. An industrial furnace according to claim 4, characterized in that the filling aperture (8) is disposed above the conveyor belt and upstream of the heat transferring device (15), viewed in the conveying direction.
6. An industrial furnace according to claim 1, characterized in that the heat transferring rollers (46a... 46e) are cylindrical tubes whose diameter is between 10 mm and 80 mm, preferably between 10 mm and 50 mm.
7 An industrial furnace according to claim 1 characterized. in that the length of the heat transferring device (15) is between 0.5m and 2 m, viewed parallel with the direction of movement of the conveyor belt (12).
8. An industrial furnace according to claim 1, characterized in that at least five equidistantly disposed rollers (46a... 46e) are provided as the heat transferring device (15).
9. An industrial furnace according to claim 1, characterized in that the conveyor belt (12) is gas- permeable.
10. An industrial furnace according to claim 9, characterized in that the conveyor belt (12) consists of a plurality of spirals (56a... 56c) which are disposed parallel one beside the other and of which each adjacent pair are interconnected by means of a rod (57a... 57c) extending therethrough.
EP85111008A 1984-11-27 1985-08-31 Industrial furnace for the continuous heat treatment of articles Expired - Lifetime EP0188659B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85111008T ATE58964T1 (en) 1984-11-27 1985-08-31 INDUSTRIAL FURNACE FOR HEAT TREATMENT OF CONTINUOUS WORKPIECES.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3443112 1984-11-27
DE3443112A DE3443112C1 (en) 1984-11-27 1984-11-27 Industrial furnace for heat treatment of continuous workpieces

Publications (3)

Publication Number Publication Date
EP0188659A2 EP0188659A2 (en) 1986-07-30
EP0188659A3 EP0188659A3 (en) 1987-12-02
EP0188659B1 true EP0188659B1 (en) 1990-12-05

Family

ID=6251206

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85111008A Expired - Lifetime EP0188659B1 (en) 1984-11-27 1985-08-31 Industrial furnace for the continuous heat treatment of articles

Country Status (7)

Country Link
EP (1) EP0188659B1 (en)
AT (1) ATE58964T1 (en)
CS (1) CS261231B2 (en)
DE (2) DE3443112C1 (en)
DK (1) DK160656C (en)
NO (1) NO165045C (en)
PL (1) PL146609B1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE1017683A3 (en) * 2007-07-12 2009-03-03 Drever Internat Sa METHOD, DEVICE AND SYSTEM FOR THERMALLY TREATING A TILTED METAL STRIP.
CN105858279B (en) * 2015-01-22 2018-12-14 夏佩文 A kind of movable type high temperature material distributing machine

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1828036A (en) * 1928-06-25 1931-10-20 Frank A Fahrenwald Process of heat treating
US2319301A (en) * 1942-08-17 1943-05-18 Associated Spring Corp Contact strip annealing furnace
DE1483513A1 (en) * 1965-08-11 1969-02-13 Elektro Ind Ofenbau Veb Continuous furnace with belt conveyor, especially for operation at high temperatures and protective gas atmospheres
FR1482719A (en) * 1966-06-09 1967-05-26 Four Electr Delemont Sa Du Furnace for continuous heat treatment of metal parts

Also Published As

Publication number Publication date
CS261231B2 (en) 1989-01-12
ATE58964T1 (en) 1990-12-15
DK160656C (en) 1991-09-02
EP0188659A2 (en) 1986-07-30
DE3580840D1 (en) 1991-01-17
DK543085D0 (en) 1985-11-22
EP0188659A3 (en) 1987-12-02
DK543085A (en) 1986-05-28
PL256206A1 (en) 1986-09-23
NO853857L (en) 1986-05-28
CS849185A2 (en) 1988-05-16
DE3443112C1 (en) 1986-08-07
DK160656B (en) 1991-04-02
NO165045C (en) 1990-12-12
NO165045B (en) 1990-09-03
PL146609B1 (en) 1989-02-28

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