EP3978854B1 - Tunnel furnace for heat treatment of products, a method for operating such a tunnel furnace and the use of such a tunnel furnace - Google Patents

Tunnel furnace for heat treatment of products, a method for operating such a tunnel furnace and the use of such a tunnel furnace Download PDF

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Publication number
EP3978854B1
EP3978854B1 EP20199362.3A EP20199362A EP3978854B1 EP 3978854 B1 EP3978854 B1 EP 3978854B1 EP 20199362 A EP20199362 A EP 20199362A EP 3978854 B1 EP3978854 B1 EP 3978854B1
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EP
European Patent Office
Prior art keywords
kiln
gas
chamber
furnace
tunnel
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.)
Active
Application number
EP20199362.3A
Other languages
German (de)
French (fr)
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EP3978854A1 (en
Inventor
Andreas Hajduk
Rainer Gundel
Andreas OVERHOFF
Matthias Uhl
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.)
Riedhammer GmbH
Riedhammer GmbH and Co KG
Original Assignee
Riedhammer GmbH
Riedhammer GmbH and Co KG
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Filing date
Publication date
Priority to EP20199362.3A priority Critical patent/EP3978854B1/en
Priority to DK20199362.3T priority patent/DK3978854T3/en
Priority to SI202030123T priority patent/SI3978854T1/en
Priority to ES20199362T priority patent/ES2929591T3/en
Priority to PT201993623T priority patent/PT3978854T/en
Application filed by Riedhammer GmbH, Riedhammer GmbH and Co KG filed Critical Riedhammer GmbH
Priority to HUE20199362A priority patent/HUE060601T2/en
Priority to PL20199362.3T priority patent/PL3978854T3/en
Publication of EP3978854A1 publication Critical patent/EP3978854A1/en
Application granted granted Critical
Publication of EP3978854B1 publication Critical patent/EP3978854B1/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
    • F27B9/04—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
    • 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
    • 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
    • F27B9/26—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 on or in trucks, sleds, or containers
    • 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
    • F27B9/3005—Details, accessories, or equipment peculiar to furnaces of these types arrangements for circulating 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
    • F27B9/30—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B9/3005—Details, accessories, or equipment peculiar to furnaces of these types arrangements for circulating gases
    • F27B9/3011—Details, accessories, or equipment peculiar to furnaces of these types arrangements for circulating gases arrangements for circulating gases transversally
    • 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
    • F27D11/00—Arrangement of elements for electric heating in or on furnaces
    • F27D11/02—Ohmic resistance heating
    • 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
    • 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
    • F27B9/3005—Details, accessories, or equipment peculiar to furnaces of these types arrangements for circulating gases
    • F27B9/3011—Details, accessories, or equipment peculiar to furnaces of these types arrangements for circulating gases arrangements for circulating gases transversally
    • F27B2009/3016—Details, accessories, or equipment peculiar to furnaces of these types arrangements for circulating gases arrangements for circulating gases transversally with arrangements to circulate gases through the charge
    • 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
    • F27B9/3005—Details, accessories, or equipment peculiar to furnaces of these types arrangements for circulating gases
    • F27B2009/3038—Fumes or gases alternatively changing their longitudinal direction
    • 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
    • F27D2003/125—Charging cars, lift trolleys
    • F27D2003/128—Charging cars, lift trolleys for carrying stacks of articles, e.g. bricks

Definitions

  • the invention relates to a tunnel kiln for the heat treatment of products, a method for operating such a tunnel kiln and the use of such a tunnel kiln.
  • a tunnel kiln which is also referred to as a continuous kiln, is a continuous kiln type, i.e. an industrial kiln that is continuously charged with products to be heat-treated in the kiln.
  • a tunnel kiln has a tunnel-like kiln space through which the products to be treated with heat are continuously moved and are thereby subjected to heat.
  • the tunnel-like furnace space extends from a first end, at which the products are introduced into the furnace space, to an opposite second end, at which the products are discharged from the furnace space again after their heat treatment in the furnace space.
  • Tunnel kilns are usually operated according to the countercurrent principle.
  • Fresh air is introduced into the furnace chamber at the second end, which is also referred to as the furnace outlet, then passed through the furnace chamber and discharged out of the furnace chamber again at the first end, which is also referred to as the furnace inlet.
  • Means for heating the furnace space usually in the form of gas burners, are arranged in the central area of the furnace space, which is also referred to as the combustion zone.
  • the fresh air introduced into the furnace chamber at the second end is therefore initially relatively cool, is heated up in the combustion zone, and this hot combustion gas is then conducted further to the first end of the furnace chamber and discharged from the furnace there.
  • Products transported through the furnace chamber are therefore first preheated by the heated combustion gases, thermally treated in the furnace chamber by the hot gases and then indirectly cooled by a heat exchanger before leaving the furnace chamber.
  • These three zones of the furnace chamber of a tunnel kiln are therefore also referred to as the heating zone, holding zone and cooling zone.
  • Rail-guided kiln cars are known for transporting the products through the kiln space. These kiln cars are usually moved by cables or other mechanical drive means.
  • U.S. 2008/0116621 A1 describes a tunnel kiln in the form of a debinding furnace with gas burners.
  • GB886524A discloses a tunnel kiln that uses pulse burners to heat the kiln cavity pressurize
  • U.S. 2010/0127418 A1 and WO 2007/111045 A1 disclose roller ovens having electric heating elements.
  • the invention has for its object to provide a tunnel furnace for the heat treatment of products available, which is particularly advantageous for the heat treatment of powdered products can be used.
  • the object of the invention is to provide a tunnel kiln for the heat treatment of powdery products, in which the turbulence of the powdery products during the heat treatment in the tunnel kiln can be avoided.
  • the object of the invention is to provide a method for operating such a tunnel kiln.
  • the provision of the tunnel kiln according to the invention is based in particular on the knowledge according to the invention that turbulence of powdered products is caused in particular by horizontal flows of the gases in the kiln space in the region of the powder to be heat-treated in the tunnel kiln.
  • these horizontal gas flows are caused in particular by the gas flow along the longitudinal axis of the furnace chamber, i.e. along the transport direction of the kiln cars in the conventional tunnel kilns operated according to the countercurrent principle.
  • a basic idea of the invention is therefore to avoid horizontal gas flows in the furnace space, particularly in the area of the products to be fired.
  • a central idea of the invention is to generate a gas flow directed essentially vertically upwards in the area of the products to be burned. This also means in particular a departure from the usual countercurrent principle when operating the tunnel kiln according to the invention.
  • the gas outlets and gas inlets of the tunnel kiln according to the invention are provided in order to enable a vertically upward gas flow during operation of the tunnel kiln according to the invention. These gas outlets or gas inlets, which are specifically arranged according to the invention, enable the combustion gases to flow essentially vertically upwards in the furnace chamber.
  • these gas outlets and gas inlets are supplemented synergistically by the specific arrangement of the kiln furniture, which is arranged on the kiln car to form a vertical gap between the kiln furniture. According to the invention, it was recognized that the formation of such vertical gaps between the kiln furniture can generate or support a gas flow directed vertically upwards in the furnace chamber.
  • the tunnel furnace according to the invention is used in particular for the heat treatment of products in the form of powder.
  • the tunnel furnace according to the invention has proven to be particularly advantageous for the heat treatment of products in the form of cathode material, in particular such a cathode material in powder form.
  • the tunnel furnace according to the invention has been found for the synthesis of such powdered cathode material.
  • the furnace chamber of the tunnel furnace according to the invention can essentially be designed according to the prior art.
  • the furnace ceiling can be designed as known from the prior art, preferably as a flat ceiling or vaulted ceiling, but preferably as a vaulted ceiling.
  • the furnace roof can preferably consist of refractory bricks, in particular refractory ceramic bricks, particularly preferably bricks based on Al 2 O 3 , in particular bricks with an Al 2 O 3 content of at least 97% by mass, more preferably at least 99% by mass -%, based on the mass of the stones.
  • the gas outlets in the furnace roof can be provided in particular in the form of openings in the furnace roof.
  • a plurality of gas outlets are preferably provided, preferably distributed over the furnace roof, particularly preferably distributed evenly over the furnace roof, in particular distributed over the length of the furnace.
  • the gas outlets are arranged in the middle of the furnace roof. If the furnace ceiling is designed as a vault, the outlets are preferably arranged at the apex of the vault, with the apex of the vault preferably running in the middle of the furnace ceiling.
  • the gas outlets preferably open into gas lines through which the gas that can be let out of the gas outlets can be conducted.
  • blowers are preferably provided, through which the gas that can be discharged from the gas outlets can be drawn off and passed on, in particular via the gas lines.
  • Such fans are preferably provided entirely or partially outside the furnace space.
  • the blowers can have a socket which, for example, can also reach into the furnace space into which the gas outlets open.
  • the gas lines for conducting the gas that can be let out of the gas outlets preferably lead to at least one of these fans in each case.
  • the furnace walls preferably run vertically and are preferably made of refractory bricks, in particular refractory ceramic bricks.
  • the furnace walls can preferably consist of refractory bricks, in particular refractory ceramic bricks, particularly preferably bricks based on Al 2 O 3 , in particular bricks with an Al 2 O 3 content of at least 97% by mass, more preferably at least 99% by mass -%, based on the mass of the stones.
  • the gas inlets are preferably provided in the form of openings in the furnace walls.
  • a plurality of gas inlets are preferably provided, preferably distributed over the furnace walls, particularly preferably distributed evenly over the furnace walls.
  • gas can be introduced very uniformly into the furnace chamber via the gas inlets, as a result of which turbulence of powdery products to be heat-treated in the furnace chamber can be avoided.
  • the gas inlets are preferably arranged at a distance from one another along the transport direction, particularly preferably distributed uniformly over the length of the furnace. This allows over the furnace length Gas can be introduced particularly evenly into the furnace chamber, which in turn avoids turbulence of powdery products in the furnace chamber.
  • both the gas outlets and the gas inlets are distributed over the length of the furnace, in particular distributed evenly over the length of the furnace, a particularly uniform vertically upward gas flow can be generated in the furnace space.
  • the flow cross section of the gas inlets is adjustable. This has the particular advantage that the flow volume and the flow distribution of the gas that can be introduced into the furnace chamber via these gas inlets can be adjusted.
  • the gas inlets are arranged in such a way that gas can be introduced into the furnace chamber below the kiln furniture via the gas inlets.
  • This has the advantage, in particular, that the gas introduced into the furnace chamber via these gas inlets does not lead to any turbulence of powdery products in the furnace chamber.
  • gas inlets are preferably arranged at the lower end of the furnace walls, ie on the region of the furnace walls adjacent to the furnace floor. Gas can preferably be introduced horizontally into the furnace space via these gas inlets, so that the powdered products are prevented from being directly impacted by the gas introduced into the furnace space from these gas inlets, and turbulence of these products can thereby be prevented.
  • gas can be introduced into the furnace chamber via the gas inlets exclusively below the kiln furniture.
  • gas to be able to be introduced into the furnace space at different heights via the gas inlets, ie at different (vertical) heights of the furnace space.
  • the gas inlets can be arranged at different heights on the furnace walls.
  • a particular advantage of this embodiment is that gas can be introduced into the oven space distributed over the height of the oven space, whereby gas can be introduced very evenly into the oven space and thus turbulence of powdered products in the oven space can be prevented.
  • gas can also be introduced into the furnace chamber via the gas inlets in the area or at the level of the products to be treated in the furnace chamber.
  • gas can also be introduced into the furnace chamber via gas inlets below the kiln furniture, with regard to these gas inlets, through which gas below the kiln furniture can enter the furnace chamber can be introduced, gas can be introduced into the furnace chamber at a higher speed than through the further gas inlets, in particular those further gas inlets through which gas can be introduced into the furnace chamber at the level of the products to be treated in the furnace chamber.
  • gas can be fed into the furnace chamber below the kiln furniture via the gas inlets, this gas can then flow vertically upwards and in particular also flow upwards through the vertical gaps formed between the kiln furniture to the furnace roof, where the gas is then discharged from the furnace chamber via the gas outlets becomes.
  • the products in the kiln furniture are essentially subjected to heat from the combustion gases directed vertically upwards.
  • Gas can be introduced into the furnace chamber below all kiln furniture. This has the particular advantage that all kiln furniture can be charged with gas on the underside, which can then flow vertically upwards between all kiln furniture, so that all kiln furniture, i.e. over the entire width of the furnace chamber, is evenly filled with gas, in particular by a gas flow directed vertically upwards , can be applied.
  • a further advantage of gas that can be introduced into the furnace chamber below the kiln furniture is, in particular, that the products located in the kiln furniture can be thermally treated very advantageously, since in particular heat losses from the products that are arranged in the lower kiln furniture can be compensated.
  • further gas inlets are provided at the level of the kiln furniture, these can be provided in particular for charging the kiln furniture adjacent to the furnace wall with gas.
  • gas inlets and gas outlets can therefore be arranged in such a way that gas can be guided through the furnace chamber, forming an upward flow, in particular a vertically upward flow.
  • gas inlets and the gas outlets can be arranged in such a way that gas can be guided through the furnace chamber while avoiding a horizontally directed flow.
  • the gas inlets and the gas outlets can therefore be arranged in such a way that gas is avoided a gas flow can be guided through the furnace chamber according to the countercurrent principle.
  • the gas inlets and the gas outlets can be arranged in such a way that gas can be guided through the furnace space in the transport direction while avoiding a gas flow.
  • the gas inlets are preferably connected to gas lines which open into the gas inlets and via which the gas which can be introduced into the furnace chamber through the gas inlets can be routed to the gas inlets.
  • the gas outlets open into the gas lines described above, via which this gas can in turn be routed to the gas inlets.
  • gas can be circulated through the tunnel kiln. As explained above, this gas circulation can be supported by means of the fans.
  • blowers A particular advantage of the use of blowers is that they can contribute to an equalization of the furnace gases drawn off from the furnace space.
  • the tunnel furnace according to the invention has means for heating the furnace space.
  • the means for heating the furnace chamber are electric heating elements.
  • electrical heating elements are resistance heating elements which, because of their electrical resistance, heat up when electrical current is passed through them.
  • Ceramic heating elements are particularly preferred, in particular non-oxidic ceramic heating elements, in particular ceramic heating elements made of SiC (silicon carbide) or SiN (silicon nitride). Provision is preferably made for the furnace chamber to be able to be subjected to heat by the electrical heating elements predominantly by means of convection and less by means of radiation.
  • the advantage of subjecting the oven chamber to convection heat is, in particular, that the products located in the oven chamber can be subjected to heat more evenly as a result, since essentially no shielding effects occur in this respect.
  • the gas that can be introduced into the furnace chamber through the gas inlets can be heated by the heating elements. It is provided that the gas that can be introduced into the furnace chamber through the gas inlets can be heated by the heating elements before the gas is introduced into the furnace chamber. In this respect, the gas that can be introduced into the furnace chamber is first heated by the heating elements and then through the gas inlets into the furnace chamber initiated. For this purpose, provision can be made for gas to first be routed past the heating elements in such a way that the gas is heated and then introduced into the furnace space through the gas inlets.
  • gas is initially routed past the heating elements by means of the aforementioned gas lines in such a way that the gas is heated and then introduced through the gas inlets into the furnace chamber.
  • the gas is discharged from the furnace chamber via the gas outlets, then guided past the heating elements in such a way that the gas is heated by them, and then the gas is introduced into the furnace chamber via the gas inlets.
  • the gas can be conducted via gas lines from the gas outlets to the heating elements and then on to the gas inlets.
  • the gas flow can, as explained above, be supported by blowers.
  • the heated gas introduced into the furnace space through the gas inlets can be used to heat the furnace space to a desired temperature.
  • the furnace chamber is heated to the desired temperature for the heat treatment of the products contained in the kiln furniture.
  • the tunnel furnace according to the invention is also particularly suitable for the heat treatment of products at high temperatures, in particular also at at least 300°C or at least 700°C.
  • the furnace chamber can be heated to a temperature in the range from 300 to 1200°C, in the range from 700 to 1200°C, in the range from 300 to 1000°C and in particular
  • the tunnel furnace according to the invention is used for the heat treatment of products in the form of cathode material, in particular for the synthesis of powdery cathode material, it can be provided that the furnace chamber is heated to a temperature in the range from 1000 to 1200°C.
  • a gas distribution space is formed below the kiln furniture.
  • This gas distribution space is used in particular to distribute fuel gas evenly underneath the kiln furniture, so that the equalized gas can then rise vertically from the gas distribution space between the kiln furniture.
  • the products in the kiln furniture can be supplied with fuel gas and thus with heat very evenly.
  • the kiln furniture can preferably rest on supports that are spaced apart from one another, the supports preferably resting on the kiln cars.
  • the supports can preferably be ceramic, in particular refractory ceramic bricks.
  • the gas distribution space is preferably formed between the top of the kiln car and the kiln furniture.
  • Gas can particularly preferably be introduced into this gas distribution space via the gas inlets.
  • Gas can particularly preferably be introduced into the gas distribution space via the above-mentioned gas inlets, via which gas can be introduced into the furnace space below the kiln furniture.
  • the kiln furniture is arranged on the kiln car, forming at least one vertical gap between the kiln furniture.
  • vertical column gases between the kiln furniture can vertically upwards to the pour oven cover.
  • At least one of the at least one vertical gaps between the kiln furniture particularly preferably runs in the transport direction.
  • Several of the vertical gaps preferably run in the transport direction. According to the invention, it was recognized that such gaps between the kiln furniture running vertically in the direction of transport not only generate a vertically upward flow of gases in the furnace space, but also at the same time a gas flow of gases in the furnace space in the direction of transport can be particularly effectively suppressed.
  • the kiln furniture can be arranged on the kiln car at a horizontal distance from one another.
  • the kiln furniture are spaced apart from one another transversely to the transport direction, forming at least one vertical gap between the kiln furniture on the kiln car, in order to form at least one gap between the kiln furniture in the transport direction.
  • vertical gaps can also be formed transversely to the transport direction between the kiln furniture, for which purpose the kiln furniture can be spaced apart from one another along the transport direction, forming at least one vertical gap between the kiln furniture on the kiln car.
  • kiln furniture that can be stacked, in particular kiln furniture that can be stacked on top of one another, particularly preferably kiln furniture that can be stacked vertically on top of one another.
  • kiln furniture is provided in the form of cassettes, that is to say in the form of "boxes", in particular with a rectangular outer contour (in plan).
  • the kiln furniture can be arranged next to one another on the kiln car in a particularly simple and effective manner in such a way that vertical gaps can be formed between the kiln furniture.
  • the products are picked up by the kiln furniture.
  • the powders are included in the kiln furniture, ie in the case of kiln furniture in the form of cassettes or boxes, they are included in the cassettes or boxes.
  • the firing aids preferably consist of graphite or ceramic, for example an oxide ceramic or a non-oxide ceramic, particularly preferably a non-oxide ceramic, in particular a nitridic or carbidic non-oxide ceramic, particularly preferably SiC, in particular silicate or ceramic bonded SiC.
  • the kiln furniture is stacked vertically one above the other in such a way that a passage through which a flow can flow is formed between vertically adjacent kiln furniture.
  • the kiln furniture is in the form of cassettes, provision can be made, for example, for these cassettes to have closed walls in their lower area, so that powdery products can be safely accommodated in the cassettes, and for the walls of the cassettes to have openings in their upper area, Have holes or other openings through which combustion gases can flow between vertically adjacent cassettes.
  • the kiln cars can be designed according to the prior art.
  • the kiln cars can be moved through the kiln chamber on rails, for example.
  • To move the kiln cars they can be moved, for example, by means of cable pulls or similar mechanical drive means.
  • the kiln cars can (in top view) have an essentially rectangular outer contour.
  • the kiln cars each have an upper side on which the kiln furniture can be arranged.
  • the kiln furniture can preferably be placed on top of the kiln cars.
  • the upper side of the kiln car is preferably designed as a flat surface, preferably with a rectangular outer contour.
  • the tops of the kiln cars preferably delimit the bottom of the kiln space, ie they form the kiln floor.
  • the tunnel furnace is preferably sealed in a gas-tight manner.
  • the outside of the tunnel furnace is formed by a gas-tight jacket, preferably by a gas-tight steel housing.
  • the gas-tight steel housing particularly preferably also encloses the kiln cars located in the kiln space.
  • the gas-tight steel housing thus also encloses the kiln roof, the kiln walls and the kiln cars.
  • the gas-tight steel housing preferably runs below the kiln cars, so that the kiln cars are also enclosed in a gas-tight manner.
  • closure means can be provided by which the furnace space can be closed in a gas-tight manner, but which prevent Allow kiln cars in and out of the kiln room.
  • locks can preferably be provided at the first end and the second end. Appropriate locks at the first end and second end of the furnace chamber allow kiln cars to be moved into and out of the furnace chamber, and at the same time the furnace chamber remains permanently enclosed in a gas-tight manner.
  • An oxidic furnace atmosphere particularly preferably prevails in the furnace chamber or the tunnel furnace according to the invention is operated with an oxidic furnace atmosphere.
  • it can also be provided to operate the tunnel kiln with a reducing kiln atmosphere, for example if kiln furniture made of graphite is provided.
  • the proportion of oxygen gas in the furnace atmosphere is preferably more than 95% by volume. However, provision can also be made for the furnace to be operated with an air atmosphere, ie with an oxygen gas content of approximately 21% by volume. If the tunnel kiln is operated with a reducing kiln atmosphere, the kiln can be operated, for example, with nitrogen as the process gas and, for example, with a proportion of residual oxygen below 100 ppm.
  • a particular advantage of the tunnel kiln according to the invention is, in particular, that it can be made available in practically any length (in the transport direction), in particular with a length of more than 50 m at least 120 m, in particular of at least 150 m.
  • the tunnel kiln can have a length in the range of 50-250 m, for example.
  • the tunnel kiln preferably has a length in the range of 120-250 m, more preferably in the range of 150-250 m and even more preferably in the range of 150-200 m.
  • the method according to the invention can include the stipulations described herein for operating the tunnel kiln according to the invention.
  • the subject matter of the invention is also the use of a device according to the invention.
  • Tunnel kiln according to any one of claims 1-11 for heat treatment of products in the form of powder. It is preferably used with the proviso that the tunnel furnace is used for the heat treatment of products in the form of powdered cathode material, in particular for the synthesis of powdered cathode material.
  • figure 1 shows a view of a cross section of the tunnel kiln perpendicular to the transport direction or longitudinal axis of the tunnel kiln, the tunnel kiln being identified in its entirety with the reference numeral 1.
  • the transport direction and longitudinal axis of the tunnel kiln 1 run in figure 1 perpendicular to the drawing plane.
  • the long axis is in the figures 2 and 3 denoted by L, the transport direction along the Longitudinal axis L in the figures 2 and 3 runs to the right.
  • the tunnel kiln 1 comprises a tunnel-like kiln chamber 2, which extends perpendicular to the plane of the drawing from a first end (in front of the plane of the drawing) to a second end (behind the plane of the drawing) of the kiln chamber 2, with the kiln chamber 2 being covered on the top by a kiln ceiling 3 and on the side by a first, in figure 1 left, oven wall 4 and a second, in figure 1 right, furnace wall 5 is limited.
  • the tunnel kiln 1 also includes kiln cars 6, which are mounted on wheels 7 on rails 8 along the transport direction, i.e. in figure 1 perpendicular to the plane and in the figures 2 and 3 to the right, through furnace room 2.
  • Kiln furniture 9 for receiving products are arranged on the kiln car 6 .
  • the furnace roof 3 is made of refractory ceramic bricks. Arranged at equal distances from one another in the center of the furnace roof 3 are gas outlets 10 in the form of openings passing through the furnace roof 3, of which one such gas outlet 10 can be seen in the figures.
  • the gas outlets 10 are arranged at a uniform distance from one another along the transport direction on the furnace roof 3 .
  • the gas outlets 10 lead to a fan 12 driven by a motor 11.
  • the vertical furnace walls 4, 5 are made of refractory ceramic bricks.
  • gas inlets 17, 18, 19 are provided in the form of openings passing through the furnace walls 4, 5.
  • the gas inlets 17, 18, 19 are arranged at different heights on the furnace walls 4, 5 along the direction of transport, spaced evenly apart from one another over the length of the furnace.
  • lower gas inlets 17 located opposite one another on the side walls 4, 5, gas inlets 18 arranged above them and gas inlets 19 arranged above them in turn are arranged on the side walls 4, 5.
  • the lowest gas inlets 17 are arranged in such a way that this gas can be introduced below the kiln furniture 9 into the furnace space 2 .
  • gas can be introduced via these lowermost gas inlets 17 into a gas distribution space 20 formed below the kiln furniture 9, indicated by the arrows P1.
  • Gas can be introduced horizontally into the furnace chamber 2 via the gas inlets 17, 18, 19, with gas being able to be introduced into the furnace chamber 2 at a higher speed via the lower gas inlets 17 than through the gas inlets 18, 19 arranged above.
  • the refractory ceramic bricks of the furnace roof 6 and the furnace walls 4, 5 are high-alumina bricks with an Al 2 O 3 content of more than 99% by mass, based on the mass of the bricks.
  • the tunnel kiln 1 is formed on the outside by a steel housing 27 which seals the tunnel kiln 1 gas-tight to the outside.
  • the steel housing 27 has an essentially rectangular contour with a horizontally extending ceiling 27.1, a horizontally extending floor 27.2 and two vertical walls 27.3, 27.4.
  • a suspended ceiling 16 made of refractory ceramic bricks is suspended from the ceiling 27.1, which runs above the furnace ceiling 3 at a distance from it.
  • a free space 13 is formed between the furnace ceiling 3 and the suspended ceiling 16 above the furnace ceiling 3 .
  • the two walls 27.3, 27.4 of the steel jacket 27 are lined on the inside with a covering of refractory bricks 14, 15, which reaches up to the side walls 4, 5 at the level of the side walls 4, 5.
  • the lining of refractory bricks 14,15 has vertically extending openings 28 which extend at a distance from one another between the walls 27.3,27.4 and the side walls 4,5.
  • the gas inlets 17, 18, 19 extend each through the side walls 4, 5 from the furnace chamber 2 to these openings 28.
  • exhaust gas lines 31 are guided, which open at one end into the free space 13 and at the other end into valves 33 in the ceiling 27.1.
  • fresh gas lines 32 are passed through the panels 14, 15, which open at one end into the openings 28 and at the other end into valves 34 in the walls 27.3, 27.4.
  • the electrical heating elements 21 extend from the false ceiling 16 through the void 13 and through the openings 28.
  • the electrical heating elements 21 are SiC ceramic heating elements.
  • the kiln cars 6 are designed essentially according to the prior art. In this respect, the kiln cars 6 can be moved along the transport direction via wheels 7 on rails 8, and they can be moved via cables (not shown).
  • the kiln cars 6 have a (viewed from above) essentially rectangular outer contour.
  • the top 22 of the kiln car 6 is designed as a flat surface and delimits the kiln chamber 2 on the underside. To the side, the kiln cars 6 are each sealed off from the foundation 24 of the panels 14 , 15 of the tunnel kiln 1 via a labyrinth seal 23 .
  • the top 22 of the kiln car 6 serves as a support for the kiln cars 9.
  • the kiln cars 9 are placed on top 22 of the kiln cars 6 by means of supports 25 in the form of refractory ceramic bricks at a distance from them.
  • the gas distribution space 20 is formed between the kiln car 6 and the kiln furniture 9 .
  • the firing aids 9 consist of cassettes made of vitrified SiC that can be stacked vertically one on top of the other.
  • the firing aids 9 have a rectangular outer contour (in plan view).
  • the kiln furniture 9 has closed walls in its lower region and openings in its upper region, so that a passage through which a flow can flow remains between vertically adjacent kiln furniture 9 stacked on top of one another.
  • kiln furniture 9 are stacked one on top of the other.
  • the stacks are each arranged in rows on the kiln car 6 in the transport direction. Three of these rows are arranged next to one another transversely to the transport direction in such a way that a vertical gap 26 remains between the kiln furniture 9 in each case between adjacent rows of the kiln furniture 9 stacked on top of one another.
  • Powdered cathode material is arranged in each of the kiln furniture 9 .
  • the tunnel furnace 1 On the first, in figure 3 left end of the furnace chamber 2, the tunnel furnace 1 has an inlet lock 29 and on the second, in figure 3 Right end of the furnace chamber 2 an outlet lock 30 for gas-tight sealing of the furnace chamber 2 according to the prior art.
  • the inlet sluice 29 and the outlet sluice 30 allow kiln cars 6 to be moved in and out of the kiln space 2, with the kiln space 2 being able to be sealed gas-tight at the same time.
  • the tunnel kiln 1 has a length of about 150 m in the transport direction.
  • the tunnel kiln 1 shown in the figures is operated as follows: The kiln cars 6 are pushed into the furnace chamber 2 through the inlet lock 29, then moved continuously in the direction of transport along the longitudinal axis L through the furnace chamber 2 and, after the furnace journey, are removed again from the furnace chamber 2 through the outlet lock 30 located at the second end of the furnace chamber 2.
  • the gas in the furnace chamber 2 is discharged from the furnace chamber 2 via the gas outlets 10 .
  • This discharge of gas from the furnace chamber 2 via the gas outlets 10 is supported by the fan 12 driven by the motor 11, which, after discharge from the gas outlets 10, first blows the furnace gases into the free space 13 (indicated by the arrows P3), on to the ceramic Heating elements 21 and along them, further through the openings 28 and finally through the gas inlets 17, 18, 19 back into the furnace chamber 2 promotes.
  • the furnace gas is heated as it slides past the ceramic heating elements 21, so that the correspondingly heated gas is then fed back into the furnace chamber 2 via the gas inlets 17, 18, 19, indicated by the arrows P1.
  • the heated gas is introduced via the lower gas inlets 17 into the gas distribution chamber 20 and via the gas inlets 18, 19 arranged above it in the direction of the respective outer rows of stacked kiln furniture 9, which are respectively adjacent to the side walls 4, 5.
  • the introduced gas is distributed in the gas distribution space 20 and then flows through the gaps formed between the kiln furniture 9 26 vertically upwards (indicated by the arrows P2) to the area of the furnace roof 3, where it again leaves the furnace chamber 2 via the gas outlets 10.
  • the gas introduced into the furnace chamber 2 via the gas inlets 18, 19 flows vertically upwards between the outer stacks of the kiln furniture 9 and the side walls 4, 5 to the area of the furnace roof 3, where it also leaves the furnace chamber 2 via the gas outlets 10. Accordingly, gas is continuously circulated in the circuit.
  • the combustion gases in the furnace space 2 can flow essentially vertically upwards. A flow of the combustible gases in the horizontal direction and, in particular, also in the transport direction can be practically completely avoided.
  • Fuel gas can be withdrawn from the free space 13 via the exhaust gas lines 31, discharged from the furnace 1 by opening the valves 33 and supplied to an exhaust gas treatment.
  • Fresh gas can also be supplied to the fuel gas.
  • fresh gas for example air or oxygen, can be introduced into the circuit of the combustion gases in the area of the openings 28 by opening the valves 34 via the fresh gas lines 32 .
  • the tunnel kiln 1 is operated with an oxidizing kiln atmosphere, the oxygen concentration in the kiln chamber 2 being over 95% by volume.
  • the furnace chamber is heated via the ceramic heating elements 21 in such a way that the temperature in the furnace chamber 2 is approximately 1,100°C.
  • the powdery cathode material located in the kiln furniture 9 can be synthesized.

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  • Tunnel Furnaces (AREA)

Description

Die Erfindung betrifft einen Tunnelofen zur Wärmebehandlung von Produkten, ein Verfahren zum Betreiben eines solchen Tunnelofens sowie die Verwendung eines solchen Tunnelofens.The invention relates to a tunnel kiln for the heat treatment of products, a method for operating such a tunnel kiln and the use of such a tunnel kiln.

Bei einem Tunnelofen, der auch als Durchlaufofen bezeichnet wird, handelt es sich um einen kontinuierlichen Ofentyp, also einen Industrieofen, der kontinuierlich mit im Ofen durch Wärme zu behandelnden Produkten chargiert wird. Hierzu weist ein Tunnelofen einen tunnelartigen Ofenraum auf, durch den die mit Wärme zu behandelnden Produkte kontinuierlich bewegt und dabei mit Wärme beaufschlagt werden. Der tunnelartige Ofenraum erstreckt sich von einem ersten Ende, an dem die Produkte in den Ofenraum eingeführt werden, bis zu einem gegenüberliegenden zweiten Ende, an dem die Produkte nach ihrer Wärmebehandlung im Ofenraum wieder aus dem Ofenraum ausgeführt werden. Tunnelöfen werden in der Regel nach dem Gegenstromprinzip betrieben. Dabei wird am zweiten Ende, das auch als Ofenauslass bezeichnet wird, Frischluft in den Ofenraum eingeleitet, anschließend durch den Ofenraum hindurchgeleitet und am ersten Ende, das auch als Ofeneinlass bezeichnet wird, wieder aus dem Ofenraum ausgeleitet. Im mittleren Bereich des Ofenraums, der auch als Brennzone bezeichnet wird, sind Mittel zum Beheizen des Ofenraums, üblicherweise in Form von Gasbrennern, angeordnet. Die in den Ofenraum am zweiten Ende eingeführte Frischluft ist daher zunächst verhältnismäßig kühl, wird in der Brennzone aufgeheizt, dieses heiße Brenngas anschließend weiter zum ersten Ende des Ofenraums geführt und dort aus dem Ofen ausgeleitet. Durch den Ofenraum transportierte Produkte werden daher zunächst durch die aufgeheizten Brenngase vorgeheizt, im Brennraum durch die heißen Gase thermisch behandelt und anschließend, vor Verlassen des Ofenraums, durch einen Wärmetauscher indirekt gekühlt. Diese drei Zonen des Ofenraums eines Tunnelofens werden daher auch als Aufheizzone, Haltezone und Kühlzone bezeichnet. Um Temperaturverluste am Ofeneinlass und Ofenauslass zu reduzieren, ist es bekannt, den Ofeneinlass und Ofenauslass durch Schließvorrichtungen, beispielsweise in Form von Schleusen, verschließbar zu gestalten.A tunnel kiln, which is also referred to as a continuous kiln, is a continuous kiln type, i.e. an industrial kiln that is continuously charged with products to be heat-treated in the kiln. For this purpose, a tunnel kiln has a tunnel-like kiln space through which the products to be treated with heat are continuously moved and are thereby subjected to heat. The tunnel-like furnace space extends from a first end, at which the products are introduced into the furnace space, to an opposite second end, at which the products are discharged from the furnace space again after their heat treatment in the furnace space. Tunnel kilns are usually operated according to the countercurrent principle. Fresh air is introduced into the furnace chamber at the second end, which is also referred to as the furnace outlet, then passed through the furnace chamber and discharged out of the furnace chamber again at the first end, which is also referred to as the furnace inlet. Means for heating the furnace space, usually in the form of gas burners, are arranged in the central area of the furnace space, which is also referred to as the combustion zone. The fresh air introduced into the furnace chamber at the second end is therefore initially relatively cool, is heated up in the combustion zone, and this hot combustion gas is then conducted further to the first end of the furnace chamber and discharged from the furnace there. Products transported through the furnace chamber are therefore first preheated by the heated combustion gases, thermally treated in the furnace chamber by the hot gases and then indirectly cooled by a heat exchanger before leaving the furnace chamber. These three zones of the furnace chamber of a tunnel kiln are therefore also referred to as the heating zone, holding zone and cooling zone. In order to reduce temperature losses at the furnace inlet and furnace outlet, it is known to design the furnace inlet and furnace outlet to be closable by means of closing devices, for example in the form of locks.

Zum Transport der Produkte durch den Ofenraum sind schienengeführte Ofenwagen bekannt. Diese Ofenwagen werden üblicherweise durch Seilzüge oder sonstige mechanische Antriebsmittel bewegt.Rail-guided kiln cars are known for transporting the products through the kiln space. These kiln cars are usually moved by cables or other mechanical drive means.

Grundsätzlich haben sich solche Tunnelöfen zur Wärmebehandlung von Produkten bewährt. Eine Herausforderung stellt jedoch die Wärmebehandlung von Produkten in Pulverform in solchen Tunnelöfen dar. Denn aufgrund der in den bekannten Tunnelöfen auftretenden Gasströmungen der Brenngase im Ofenraum können unerwünschte Verwirbelungen der pulverförmigen Produkte auftreten.In principle, such tunnel furnaces have proven themselves for the heat treatment of products. However, the heat treatment of products in powder form in such tunnel kilns poses a challenge. Because of the gas flows of the combustion gases occurring in the known tunnel kilns, undesirable turbulence of the powdered products can occur in the kiln chamber.

US 2008/0116621 A1 beschreibt einen Tunnelofen in Form eines Entbinderungsofens mit Gasbrennern. GB 886524 A offenbart einen Tunnelofen, der Impulsbrenner verwendet, um den Ofenraum mit Hitze zu beaufschlagen. US 2010/0127418 A1 und WO 2007/111045 A1 offenbaren Rollenöfen, die elektrische Heizelemente aufweisen. U.S. 2008/0116621 A1 describes a tunnel kiln in the form of a debinding furnace with gas burners. GB886524A discloses a tunnel kiln that uses pulse burners to heat the kiln cavity pressurize U.S. 2010/0127418 A1 and WO 2007/111045 A1 disclose roller ovens having electric heating elements.

Der Erfindung liegt die Aufgabe zugrunde, einen Tunnelofen zur Wärmebehandlung von Produkten zur Verfügung zu stellen, der in vorteilhafter Weise insbesondere auch zur Wärmebehandlung von pulverförmigen Produkten Verwendung finden kann. Insbesondere liegt der Erfindung die Aufgabe zugrunde, einen Tunnelofen zur Wärmebehandlung von pulverförmigen Produkten zur Verfügung zu stellen, bei dem die Verwirbelung der pulverförmigen Produkte während der Wärmebehandlung im Tunnelofen vermieden werden kann.The invention has for its object to provide a tunnel furnace for the heat treatment of products available, which is particularly advantageous for the heat treatment of powdered products can be used. In particular, the object of the invention is to provide a tunnel kiln for the heat treatment of powdery products, in which the turbulence of the powdery products during the heat treatment in the tunnel kiln can be avoided.

Ferner liegt der Erfindung die Aufgabe zugrunde, ein Verfahren zum Betreiben eines solchen Tunnelofens zur Verfügung zu stellen.Furthermore, the object of the invention is to provide a method for operating such a tunnel kiln.

Zur Lösung der vorstehenden Aufgaben wird zur Verfügung gestellt ein Tunnelofen zur Wärmebehandlung von Produkten, umfassend die folgenden Merkmale:

  • Einen tunnelartigen Ofenraum, der sich von einem ersten Ende zu einem zweiten Ende des Ofenraums erstreckt, wobei der Ofenraum oberseitig durch eine Ofendecke und seitlich durch Ofenwände begrenzt ist;
  • Ofenwagen, die vom ersten Ende zum zweiten Ende entlang einer Transportrichtung durch den Ofenraum fahrbar sind und auf denen im Ofenraum mit Wärme zu behandelnde Produkte transportierbar sind;
  • Brennhilfsmitteln zur Aufnahme der Produkte, wobei die Brennhilfsmittel auf den Ofenwagen angeordnet sind;
  • Gasauslässe, über die im Ofenraum befindliches Gas aus dem Ofenraum ausleitbar ist;
  • Gaseinlässe, über die Gas in den Ofenraum einleitbar ist; und
  • Mittel zum Beheizen des Ofenraums; wobei
  • über die Gasauslässe im Bereich der Ofendecke befindliches Gas aus dem Ofenraum ausleitbar ist;
  • über die Gaseinlässe Gas im Bereich der Ofenwände in den Ofenraum einleitbar ist; und wobei
  • die Brennhilfsmittel unter Ausbildung wenigstens eines vertikalen Spaltes zwischen den Brennhilfsmitteln auf den Ofenwagen angeordnet sind;
  • und die weiteren Merkmale nach Anspruch 1.
To solve the above tasks, a tunnel furnace for heat treatment of products is provided, comprising the following features:
  • A tunnel-like furnace space, which extends from a first end to a second end of the furnace space, wherein the furnace space is delimited at the top by a furnace ceiling and at the sides by furnace walls;
  • Kiln cars, which can be moved from the first end to the second end along a transport direction through the furnace chamber and on which products to be heat-treated in the furnace chamber can be transported;
  • kiln furniture for receiving the products, the kiln furniture being arranged on the kiln cars;
  • Gas outlets, via which the gas in the furnace chamber can be discharged from the furnace chamber;
  • Gas inlets through which gas can be introduced into the furnace chamber; and
  • means for heating the furnace chamber; whereby
  • Gas located in the area of the furnace ceiling can be discharged from the furnace chamber via the gas outlets;
  • Gas can be introduced into the furnace chamber via the gas inlets in the region of the furnace walls; and where
  • the kiln furniture is arranged on the kiln car, forming at least one vertical gap between the kiln furniture;
  • and the further features according to claim 1.

Die Zurverfügungstellung des erfindungsgemäßen Tunnelofens beruht insbesondere auf der erfindungsgemäßen Erkenntnis, dass Verwirbelungen pulverförmiger Produkte insbesondere durch horizontale Strömungen der im Ofenraum befindlichen Gase im Bereich der im Tunnelofen mit Wärme zu behandelnden Pulver verursacht werden. Erfindungsgemäß wurde ferner erkannt, dass diese horizontalen Gasströmungen insbesondere durch den Gasstrom entlang der Längsachse des Ofenraums, also entlang der Transportrichtung der Ofenwagen bei den gemäß dem Stand der Technik üblichen, nach dem Gegenstromprinzip betriebenen Tunnelöfen verursacht werden. Ein Grundgedanke der Erfindung besteht daher darin, horizontale Gasströmungen im Ofenraum insbesondere im Bereich der zu brennenden Produkte möglichst zu vermeiden. Insoweit besteht ein zentraler Gedanke der Erfindung darin, im Bereich der zu brennenden Produkte eine im Wesentlichen vertikal aufwärts gerichtete Gasströmung zu erzeugen. Dies bedeutet insbesondere auch eine Abkehr vom üblichen Gegenstromprinzip beim Betrieb des erfindungsgemäßen Tunnelofens. Um beim Betrieb des erfindungsgemäßen Tunnelofens eine vertikal aufwärts gerichtete Gasströmung zu ermöglichen, sind die Gasauslässe und Gaseinlässe des erfindungsgemäßen Tunnelofens vorgesehen. Diese erfindungsgemäß spezifisch angeordneten Gasauslässe oder Gaseinlässe ermöglichen eine im Wesentlichen vertikal aufwärts gerichtete Strömung der Brenngase im Ofenraum. Ferner werden diese Gasauslässe und Gaseinlässe synergistisch ergänzt um die spezifische Anordnung der Brennhilfsmittel, die unter Ausbildung eines vertikalen Spaltes zwischen den Brennhilfsmitteln auf den Ofenwagen angeordnet sind. Erfindungsgemäß wurde erkannt, dass durch die Ausbildung solch vertikaler Spalten zwischen den Brennhilfsmitteln eine vertikal aufwärts gerichtete Gasströmung im Ofenraum erzeugt beziehungsweise unterstützt werden kann.The provision of the tunnel kiln according to the invention is based in particular on the knowledge according to the invention that turbulence of powdered products is caused in particular by horizontal flows of the gases in the kiln space in the region of the powder to be heat-treated in the tunnel kiln. According to the invention, it was also recognized that these horizontal gas flows are caused in particular by the gas flow along the longitudinal axis of the furnace chamber, i.e. along the transport direction of the kiln cars in the conventional tunnel kilns operated according to the countercurrent principle. A basic idea of the invention is therefore to avoid horizontal gas flows in the furnace space, particularly in the area of the products to be fired. In this respect, a central idea of the invention is to generate a gas flow directed essentially vertically upwards in the area of the products to be burned. This also means in particular a departure from the usual countercurrent principle when operating the tunnel kiln according to the invention. The gas outlets and gas inlets of the tunnel kiln according to the invention are provided in order to enable a vertically upward gas flow during operation of the tunnel kiln according to the invention. These gas outlets or gas inlets, which are specifically arranged according to the invention, enable the combustion gases to flow essentially vertically upwards in the furnace chamber. Furthermore, these gas outlets and gas inlets are supplemented synergistically by the specific arrangement of the kiln furniture, which is arranged on the kiln car to form a vertical gap between the kiln furniture. According to the invention, it was recognized that the formation of such vertical gaps between the kiln furniture can generate or support a gas flow directed vertically upwards in the furnace chamber.

Der erfindungsgemäße Tunnelofen dient insbesondere zur Wärmebehandlung von Produkten in Form von Pulver. Als besonders vorteilhaft hat sich der erfindungsgemäße Tunnelofen zur Wärmbehandlung von Produkten in Form von Kathodenmaterial herausgestellt, insbesondere ein solches Kathodenmaterial in Pulverform. Insbesondere hat sich der erfindungsgemäße Tunnelofen zur Synthese von solch pulverförmigem Kathodenmaterial herausgestellt.The tunnel furnace according to the invention is used in particular for the heat treatment of products in the form of powder. The tunnel furnace according to the invention has proven to be particularly advantageous for the heat treatment of products in the form of cathode material, in particular such a cathode material in powder form. In particular, the tunnel furnace according to the invention has been found for the synthesis of such powdered cathode material.

Der Ofenraum des erfindungsgemäßen Tunnelofens kann im Wesentlichen gemäß dem Stand der Technik ausgebildet sein. Insoweit kann die Ofendecke, wie aus dem Stand der Technik bekannt ausgebildet sein, bevorzugt als Flachdecke oder Gewölbedecke, bevorzugt jedoch als Gewölbedecke. Bevorzugt kann die Ofendecke aus feuerfesten Steinen bestehen, insbesondere aus feuerfesten keramischen Steinen, besonders bevorzugt aus Steinen auf Basis Al2O3, insbesondere aus Steinen mit einem Gehalt an Al2O3 von wenigstens 97 Masse-%, noch bevorzugter von wenigstens 99 Masse-%, bezogen auf die Masse der Steine.The furnace chamber of the tunnel furnace according to the invention can essentially be designed according to the prior art. In this respect, the furnace ceiling can be designed as known from the prior art, preferably as a flat ceiling or vaulted ceiling, but preferably as a vaulted ceiling. The furnace roof can preferably consist of refractory bricks, in particular refractory ceramic bricks, particularly preferably bricks based on Al 2 O 3 , in particular bricks with an Al 2 O 3 content of at least 97% by mass, more preferably at least 99% by mass -%, based on the mass of the stones.

Die Gasauslässe in der Ofendecke können insbesondere in Form von Öffnungen in der Ofendecke vorgesehen sein. Bevorzugt sind mehrere Gasauslässe vorgesehen, bevorzugt über die Ofendecke verteilt, besonders bevorzugt gleichmäßig über die Ofendecke, insbesondere über die Ofenlänge verteilt. Hierdurch kann eine sehr gleichmäßige aufwärts gerichtete Vertikalströmung von Gasen im Ofenraum erreicht werden. Nach einer bevorzugten Ausführungsform sind die Gasauslässe in der Mitte der Ofendecke angeordnet. Sofern die Ofendecke als Gewölbe ausgebildet ist, sind die Auslässe bevorzugt am Scheitel des Gewölbes angeordnet, wobei der Scheitel des Gewölbes bevorzugt in der Mitte der Ofendecke verläuft.The gas outlets in the furnace roof can be provided in particular in the form of openings in the furnace roof. A plurality of gas outlets are preferably provided, preferably distributed over the furnace roof, particularly preferably distributed evenly over the furnace roof, in particular distributed over the length of the furnace. As a result, a very uniform upward vertical flow of gases in the furnace chamber can be achieved. According to a preferred embodiment, the gas outlets are arranged in the middle of the furnace roof. If the furnace ceiling is designed as a vault, the outlets are preferably arranged at the apex of the vault, with the apex of the vault preferably running in the middle of the furnace ceiling.

Die Gasauslässe münden bevorzugt in Gasleitungen, durch die das aus den Gasauslässen auslassbare Gas leitbar ist.The gas outlets preferably open into gas lines through which the gas that can be let out of the gas outlets can be conducted.

Bevorzugt sind ein oder mehrere Gebläse vorgesehen, durch die das aus den Gasauslässen auslassbare Gas abgezogen und, insbesondere über die Gasleitungen, weitergeleitet werden kann. Solche Gebläse sind bevorzugt vollständig oder teilweise außerhalb des Ofenraums vorgesehen. Soweit die Gebläse teilweise außerhalb des Ofenraums angeordnet sind, können die Gebläse einen Stutzen aufweisen, der beispielsweise auch bis in den Ofenraum reichen kann, in den die Gasauslässe münden. Bevorzugt führen die Gasleitungen zur Leitung des aus den Gasauslässen auslassbaren Gases zu jeweils wenigstens einem dieser Gebläse.One or more blowers are preferably provided, through which the gas that can be discharged from the gas outlets can be drawn off and passed on, in particular via the gas lines. Such fans are preferably provided entirely or partially outside the furnace space. Insofar as the blowers are partially arranged outside of the furnace space, the blowers can have a socket which, for example, can also reach into the furnace space into which the gas outlets open. The gas lines for conducting the gas that can be let out of the gas outlets preferably lead to at least one of these fans in each case.

Die Ofenwände verlaufen bevorzugt vertikal und sind bevorzugt aus feuerfesten Steinen, insbesondere feuerfesten keramischen Steinen gemauert. Bevorzugt können die Ofenwände aus feuerfesten Steinen bestehen, insbesondere aus feuerfesten keramischen Steinen, besonders bevorzugt aus Steinen auf Basis Al2O3, insbesondere aus Steinen mit einem Gehalt an Al2O3 von wenigstens 97 Masse-%, noch bevorzugter von wenigstens 99 Masse-%, bezogen auf die Masse der Steine.The furnace walls preferably run vertically and are preferably made of refractory bricks, in particular refractory ceramic bricks. The furnace walls can preferably consist of refractory bricks, in particular refractory ceramic bricks, particularly preferably bricks based on Al 2 O 3 , in particular bricks with an Al 2 O 3 content of at least 97% by mass, more preferably at least 99% by mass -%, based on the mass of the stones.

Die Gaseinlässe sind bevorzugt in Form von Öffnungen in den Ofenwänden vorgesehen. Bevorzugt sind mehrere Gaseinlässe, bevorzugt über die Ofenwände verteilt, besonders bevorzugt gleichmäßig über die Ofenwände verteilt vorgesehen. Hierdurch kann Gas sehr gleichförmig über die Gaseinlässe in den Ofenraum eingeleitet werden, wodurch Verwirbelungen von im Ofenraum mit Wärme zu behandelnden pulverförmigen Produkten vermieden werden können. Bevorzugt sind die Gaseinlässe entlang der Transportrichtung beabstandet voneinander angeordnet, besonders bevorzugt gleichmäßig über die Ofenlänge verteilt. Hierdurch kann über die Ofenlänge Gas besonders gleichmäßig in den Ofenraum eingeleitet werden, wodurch wiederrum Verwirbelungen von pulverförmigen Produkten im Ofenraum vermieden werden können.The gas inlets are preferably provided in the form of openings in the furnace walls. A plurality of gas inlets are preferably provided, preferably distributed over the furnace walls, particularly preferably distributed evenly over the furnace walls. As a result, gas can be introduced very uniformly into the furnace chamber via the gas inlets, as a result of which turbulence of powdery products to be heat-treated in the furnace chamber can be avoided. The gas inlets are preferably arranged at a distance from one another along the transport direction, particularly preferably distributed uniformly over the length of the furnace. This allows over the furnace length Gas can be introduced particularly evenly into the furnace chamber, which in turn avoids turbulence of powdery products in the furnace chamber.

Sofern sowohl die Gasauslässe als auch die Gaseinlässe über die Ofenlänge verteilt, insbesondere gleichmäßig über die Ofenlänge verteilt vorgesehen sind, kann eine besonders gleichmäßige vertikal aufwärts gerichtete Gasströmung im Ofenraum erzeugt werden.If both the gas outlets and the gas inlets are distributed over the length of the furnace, in particular distributed evenly over the length of the furnace, a particularly uniform vertically upward gas flow can be generated in the furnace space.

Nach einer Ausführungsform ist der Strömungsquerschnitt der Gaseinlässe verstellbar. Dies hat insbesondere den Vorteil, dass das Strömungsvolumen und die Strömungsverteilung des über diese Gaseinlässe in den Ofenraum einleitbaren Gases einstellbar ist.According to one embodiment, the flow cross section of the gas inlets is adjustable. This has the particular advantage that the flow volume and the flow distribution of the gas that can be introduced into the furnace chamber via these gas inlets can be adjusted.

Nach einer bevorzugten Ausführungsform sind die Gaseinlässe derart angeordnet, dass über die Gaseinlässe Gas unterhalb der Brennhilfsmittel in den Ofenraum einleitbar ist. Dies hat insbesondere den Vorteil, dass das über diese Gaseinlässe in den Ofenraum eingeleitete Gas zu keiner Verwirbelung von pulverförmigen Produkten im Ofenraum führt. Um Gas unterhalb der Brennhilfsmittel in den Ofenraum einleiten zu können, sind Gaseinlässe bevorzugt am unteren Ende der Ofenwände angeordnet, also an dem zum Ofenboden benachbarten Bereich der Ofenwände. Bevorzugt ist Gas über diese Gaseinlässe horizontal in den Ofenraum einleitbar, so dass eine direkte Beaufschlagung der pulverförmigen Produkte mit dem aus diesen Gaseinlässen in den Ofenraum eingeleiteten Gas verhindert und hierdurch eine Verwirbelung dieser Produkte verhindert werden kann.According to a preferred embodiment, the gas inlets are arranged in such a way that gas can be introduced into the furnace chamber below the kiln furniture via the gas inlets. This has the advantage, in particular, that the gas introduced into the furnace chamber via these gas inlets does not lead to any turbulence of powdery products in the furnace chamber. In order to be able to introduce gas below the kiln furniture into the furnace chamber, gas inlets are preferably arranged at the lower end of the furnace walls, ie on the region of the furnace walls adjacent to the furnace floor. Gas can preferably be introduced horizontally into the furnace space via these gas inlets, so that the powdered products are prevented from being directly impacted by the gas introduced into the furnace space from these gas inlets, and turbulence of these products can thereby be prevented.

Nach einer Ausführungsform kann vorgesehen sein, dass Gas über die Gaseinlässe ausschließlich unterhalb der Brennhilfsmittel in den Ofenraum einleitbar ist.According to one embodiment, it can be provided that gas can be introduced into the furnace chamber via the gas inlets exclusively below the kiln furniture.

Es ist vorgesehen, dass über die Gaseinlässe Gas in unterschiedlichen Höhen in den Ofenraum einleitbar ist, also in unterschiedlichen (vertikalen) Höhen des Ofenraums. Um dies zu erreichen, können die Gaseinlässe in unterschiedlichen Höhen an den Ofenwänden angeordnet sein. Ein besonderer Vorteil dieser Ausführungsform liegt darin, dass Gas über die Höhe des Ofenraums verteilt in den Ofenraum eingeleitet werden kann, wodurch Gas sehr gleichmäßig in den Ofenraum eingeleitet und hierdurch eine Verwirbelung von pulverförmigen Produkten im Ofenraum verhindert werden kann. Bei dieser Ausführungsform kann Gas über die Gaseinlässe auch im Bereich beziehungsweise in Höhe der im Ofenraum zu behandelnden Produkte in den Ofenraum einleitbar sein. Um dennoch eine Verwirbelung von pulverförmigen Produkten im Ofenraum verhindern zu können, kann bei dieser Ausführungsform vorgesehen sein, dass auch bei dieser Ausführungsform über Gaseinlässe Gas unterhalb der Brennhilfsmittel in den Ofenraum einleitbar ist, wobei hinsichtlich dieser Gaseinlässe, durch die Gas unterhalb der Brennhilfsmittel in den Ofenraum einleitbar ist, Gas mit einer höheren Geschwindigkeit als durch die weiteren Gaseinlässe, insbesondere solche weiteren Gaseinlässe, durch die Gas in Höhe der im Ofenraum zu behandelnden Produkte in den Ofenraum einleitbar ist, in den Ofenraum einleitbar ist.Provision is made for gas to be able to be introduced into the furnace space at different heights via the gas inlets, ie at different (vertical) heights of the furnace space. In order to achieve this, the gas inlets can be arranged at different heights on the furnace walls. A particular advantage of this embodiment is that gas can be introduced into the oven space distributed over the height of the oven space, whereby gas can be introduced very evenly into the oven space and thus turbulence of powdered products in the oven space can be prevented. In this embodiment, gas can also be introduced into the furnace chamber via the gas inlets in the area or at the level of the products to be treated in the furnace chamber. In order to nevertheless be able to prevent powdery products from being swirled around in the furnace chamber, it can be provided in this embodiment that gas can also be introduced into the furnace chamber via gas inlets below the kiln furniture, with regard to these gas inlets, through which gas below the kiln furniture can enter the furnace chamber can be introduced, gas can be introduced into the furnace chamber at a higher speed than through the further gas inlets, in particular those further gas inlets through which gas can be introduced into the furnace chamber at the level of the products to be treated in the furnace chamber.

Soweit über die Gaseinlässe Gas unterhalb der Brennhilfsmittel in den Ofenraum einleitbar ist, kann dieses Gas anschließend vertikal aufwärts strömen und insbesondere auch durch die zwischen den Brennhilfsmitteln ausgebildeten, vertikalen Spalte aufwärts bis zur Ofendecke strömen, wo das Gas anschließend über die Gasauslässe aus dem Ofenraum ausgeleitet wird. Hierdurch werden die in den Brennhilfsmitteln befindlichen Produkte im Wesentlichen durch die vertikal aufwärts gerichteten Brenngase mit Wärme beaufschlagt. Insbesondere kann vorgesehen sein, dass über die Gaseinlässe Gas unterhalb sämtlicher Brennhilfsmittel in den Ofenraum einleitbar ist. Dies hat den besonderen Vorteil, dass sämtliche Brennhilfsmittel unterseitig mit Gas beaufschlagt werden können, das anschließend zwischen sämtlichen Brennhilfsmitteln vertikal aufwärts strömen kann, so dass sämtliche Brennhilfsmittel, also über die gesamte Breite des Ofenraums, gleichmäßig mit Gas, insbesondere durch einen vertikal aufwärts gerichteten Gasstrom, beaufschlagt werden können.Insofar as gas can be fed into the furnace chamber below the kiln furniture via the gas inlets, this gas can then flow vertically upwards and in particular also flow upwards through the vertical gaps formed between the kiln furniture to the furnace roof, where the gas is then discharged from the furnace chamber via the gas outlets becomes. As a result, the products in the kiln furniture are essentially subjected to heat from the combustion gases directed vertically upwards. In particular, it can be provided that via the gas inlets Gas can be introduced into the furnace chamber below all kiln furniture. This has the particular advantage that all kiln furniture can be charged with gas on the underside, which can then flow vertically upwards between all kiln furniture, so that all kiln furniture, i.e. over the entire width of the furnace chamber, is evenly filled with gas, in particular by a gas flow directed vertically upwards , can be applied.

Ein weiterer Vorteil von unterhalb der Brennhilfsmittel in den Ofenraum einleitbarem Gas besteht insbesondere auch darin, dass die in den Brennhilfsmitteln befindlichen Produkte sehr vorteilhaft thermisch behandelt werden können, da insbesondere auch Wärmeverluste der Produkte, die in den unteren Brennhilfsmittel angeordnet sind, kompensiert werden können.A further advantage of gas that can be introduced into the furnace chamber below the kiln furniture is, in particular, that the products located in the kiln furniture can be thermally treated very advantageously, since in particular heat losses from the products that are arranged in the lower kiln furniture can be compensated.

Soweit, wie oben ausgeführt, weitere Gaseinlässe in Höhe der Brennhilfsmittel vorgesehen sind, können diese insbesondere zur Beaufschlagung der Brennhilfsmittel, die der Ofenwand benachbart sind, mit Gas vorgesehen sein.If, as stated above, further gas inlets are provided at the level of the kiln furniture, these can be provided in particular for charging the kiln furniture adjacent to the furnace wall with gas.

Insgesamt können die Gaseinlässe und Gasauslässe demnach derart angeordnet sein, dass Gas unter Ausbildung einer aufwärts gerichteten Strömung, insbesondere einer vertikal aufwärts ausgerichteten Strömung durch den Ofenraum führbar ist.Overall, the gas inlets and gas outlets can therefore be arranged in such a way that gas can be guided through the furnace chamber, forming an upward flow, in particular a vertically upward flow.

Ferner können die Gaseinlässe und die Gasauslässe, wie vorstehend ausgeführt, derart angeordnet sein, dass Gas unter Vermeidung einer horizontalen gerichteten Strömung durch den Ofenraum führbar ist.Furthermore, the gas inlets and the gas outlets, as explained above, can be arranged in such a way that gas can be guided through the furnace chamber while avoiding a horizontally directed flow.

Insbesondere können, wie vorstehend ausgeführt, die Gaseinlässe und die Gasauslässe demnach derart angeordnet sein, dass Gas unter Vermeidung einer Gasströmung nach dem Gegenstromprinzip durch den Ofenraum führbar ist.In particular, as stated above, the gas inlets and the gas outlets can therefore be arranged in such a way that gas is avoided a gas flow can be guided through the furnace chamber according to the countercurrent principle.

Insoweit können, wie vorstehend ausgeführt, die Gaseinlässe und die Gasauslässe derart angeordnet sein, dass Gas unter Vermeidung einer Gasströmung in Transportrichtung durch den Ofenraum führbar ist.In this respect, as explained above, the gas inlets and the gas outlets can be arranged in such a way that gas can be guided through the furnace space in the transport direction while avoiding a gas flow.

Die Gaseinlässe sind bevorzugt an Gasleitungen angeschlossen, die in die Gaseinlässe münden, und über die das durch die Gaseinlässe in den Ofenraum einleitbare Gas zu den Gaseinlässen leitbar ist. Nach einer besonders bevorzugten Ausführungsform ist vorgesehen, dass die Gasauslässe in die oben bezeichneten Gasleitungen münden, über die dieses Gas wiederum zu den Gaseinlässen leitbar ist. Gas ist insoweit im Kreislauf durch den Tunnelofen führbar. Diese Gasumwälzung kann dabei, wie vorstehend ausgeführt, mittels der Gebläse unterstützt werden. Ein besonderer Vorteil der Verwendung von Gebläsen besteht dabei auch darin, dass diese zu einer Vergleichmäßigung der aus dem Ofenraum abgezogenen Ofengase beitragen können.The gas inlets are preferably connected to gas lines which open into the gas inlets and via which the gas which can be introduced into the furnace chamber through the gas inlets can be routed to the gas inlets. According to a particularly preferred embodiment, it is provided that the gas outlets open into the gas lines described above, via which this gas can in turn be routed to the gas inlets. To this extent, gas can be circulated through the tunnel kiln. As explained above, this gas circulation can be supported by means of the fans. A particular advantage of the use of blowers is that they can contribute to an equalization of the furnace gases drawn off from the furnace space.

Selbstverständlich müssen nicht sämtliche der über die Gasauslässe aus dem Ofenraum abgezogenen Gase wieder über die Gaseinlässe in den Ofenraum eingeleitet und entsprechend im Kreislauf umgewälzt werden. Vielmehr kann, wie aus dem Stand der Technik bekannt, kontinuierlich ein Teil der aus dem Ofenraum abgezogenen Gase als Abgas aus dem Ofen abgezogen und ferner kontinuierlich Frischgas in den Ofen eingeleitet werden. Hierfür können die aus dem Stand der Technik bekannten Gasleitungsmittel vorgesehen sein.Of course, not all of the gases withdrawn from the furnace space via the gas outlets have to be fed back into the furnace space via the gas inlets and correspondingly circulated in the circuit. Rather, as is known from the prior art, part of the gases drawn off from the furnace chamber can be continuously drawn off as waste gas from the furnace and fresh gas can also be introduced continuously into the furnace. The gas line means known from the prior art can be provided for this purpose.

Zur Wärmebehandlung der Produkte im Ofenraum, also zur Beaufschlagung dieser Produkte mit Temperatur im Ofenraum, weist der erfindungsgemäße Tunnelofen Mittel zum Beheizen des Ofenraums auf. Bei diesen Mitteln handelt es sich um Vorrichtungen zum Beheizen des Ofenraums mit thermischer Energie. Bei den Mitteln zum Beheizen des Ofenraums handelt es sich um elektrische Heizelemente. Denn erfindungsgemäß wurde erkannt, dass die hier ungewünschten, horizontalen Gasströmungen in einem gewissen Umfang durch Gasbrenner verursacht werden können, wohingegen elektrische Heizelemente keine oder nur vernachlässigbare Gasströmungen in Horizontalrichtung im Ofenraum verursachen. Nach einer bevorzugten Ausführungsform weist der erfindungsgemäße Tunnelofen ausschließlich solch elektrische Heizelemente zum Beheizen des Ofenraums auf. Bekanntermaßen handelt es sich bei elektrischen Heizelementen um Widerstandsheizelemente, die sich aufgrund ihres elektrischen Widerstandes bei Durchleitung von elektrischem Strom aufheizen. Besonders bevorzugt sind elektrische Heizelemente in Form von keramischen Heizelementen vorgesehen, insbesondere nicht-oxidische keramische Heizelemente, insbesondere keramische Heizelemente aus SiC (Siliziumcarbid) oder SiN (Siliziumnitrid). Bevorzugt ist vorgesehen, dass der Ofenraum durch die elektrischen Heizelemente überwiegend mittels Konvektion und weniger mittels Strahlung mit Wärme beaufschlagbar ist. Der Vorteil der Beaufschlagung des Ofenraums mit Konvektionswärme liegt insbesondere auch darin, dass die im Ofenraum befindlichen Produkte hierdurch gleichmäßiger mit Wärme beaufschlagbar sind, da insoweit im Wesentlichen keine Abschirmungseffekte auftreten. Insoweit ist bevorzugt vorgesehen, dass zum Beheizen des Ofenraums mittels der elektrischen Heizelemente das im Ofenraum befindliche Gas durch die Heizelemente erhitzbar ist. Besonders bevorzugt kann vorgesehen sein, dass das durch die Gaseinlässe in den Ofenraum einleitbare Gas durch die Heizelemente erhitzbar ist. Es ist vorgesehen, dass das durch die Gaseinlässe in den Ofenraum einleitbare Gas vor Einleiten des Gases in den Ofenraum durch die Heizelemente erhitzbar ist. Insoweit wird das in den Ofenraum einleitbare Gas zunächst durch die Heizelemente erhitzt und anschließend durch die Gaseinlässe in den Ofenraum eingeleitet. Hierzu kann vorgesehen sein, Gas zunächst an den Heizelementen derart vorbeizuleiten, dass das Gas erwärmt und anschließend durch die Gaseinlässe in den Ofenraum eingeleitet wird. Nach einer besonders bevorzugten Ausgestaltung kann vorgesehen sein, dass Gas zunächst mittels der vorbezeichneten Gasleitungen zunächst an den Heizelementen derart vorbeigeleitet wird, dass das Gas erwärmt wird, und anschließend durch die Gaseinlässe in den Ofenraum eingeleitet wird. Nach einer Fortbildung dieses Erfindungsgedankens kann vorgesehen sein, dass Gas über die Gasauslässe aus dem Ofenraum ausgeleitet wird, anschließend an den Heizelementen derart vorbeigeleitet wird, dass das Gas durch diese erwärmt wird, und anschließend das Gas über die Gaseinlässe in den Ofenraum eingeleitet wird. Dabei kann das Gas, wie oben ausgeführt, über Gasleitungen von den Gasauslässen zu den Heizelementen und anschließend weiter zu den Gaseinlässen geleitet werden. Ferner kann die Gasströmung dabei, wie oben ausgeführt, durch Gebläse unterstützt werden.For heat treatment of the products in the furnace space, ie for subjecting these products to temperature in the furnace space, the tunnel furnace according to the invention has means for heating the furnace space. With these funds are devices for heating the furnace chamber with thermal energy. The means for heating the furnace chamber are electric heating elements. According to the invention, it was recognized that the undesirable, horizontal gas flows here can be caused to a certain extent by gas burners, whereas electrical heating elements cause no or only negligible gas flows in the horizontal direction in the furnace chamber. According to a preferred embodiment, the tunnel kiln according to the invention has only such electrical heating elements for heating the kiln chamber. As is known, electrical heating elements are resistance heating elements which, because of their electrical resistance, heat up when electrical current is passed through them. Electrical heating elements in the form of ceramic heating elements are particularly preferred, in particular non-oxidic ceramic heating elements, in particular ceramic heating elements made of SiC (silicon carbide) or SiN (silicon nitride). Provision is preferably made for the furnace chamber to be able to be subjected to heat by the electrical heating elements predominantly by means of convection and less by means of radiation. The advantage of subjecting the oven chamber to convection heat is, in particular, that the products located in the oven chamber can be subjected to heat more evenly as a result, since essentially no shielding effects occur in this respect. In this regard, it is preferably provided that, in order to heat the furnace space by means of the electric heating elements, the gas in the furnace space can be heated by the heating elements. Particularly preferably, it can be provided that the gas that can be introduced into the furnace chamber through the gas inlets can be heated by the heating elements. It is provided that the gas that can be introduced into the furnace chamber through the gas inlets can be heated by the heating elements before the gas is introduced into the furnace chamber. In this respect, the gas that can be introduced into the furnace chamber is first heated by the heating elements and then through the gas inlets into the furnace chamber initiated. For this purpose, provision can be made for gas to first be routed past the heating elements in such a way that the gas is heated and then introduced into the furnace space through the gas inlets. According to a particularly preferred embodiment, it can be provided that gas is initially routed past the heating elements by means of the aforementioned gas lines in such a way that the gas is heated and then introduced through the gas inlets into the furnace chamber. According to a further development of this inventive idea, it can be provided that the gas is discharged from the furnace chamber via the gas outlets, then guided past the heating elements in such a way that the gas is heated by them, and then the gas is introduced into the furnace chamber via the gas inlets. As explained above, the gas can be conducted via gas lines from the gas outlets to the heating elements and then on to the gas inlets. Furthermore, the gas flow can, as explained above, be supported by blowers.

Über das in den Ofenraum durch die Gaseinlässe eingeleitete, erhitzte Gas kann der Ofenraum auf eine gewünschte Temperatur erhitzt werden. Insbesondere wird der Ofenraum auf die gewünschte Temperatur zur Wärmebehandlung der in den Brennhilfsmitteln befindlichen Produkte erhitzt. Der erfindungsgemäße Tunnelofen eignet sich insbesondere auch zur Wärmebehandlung von Produkten bei hohen Temperaturen, insbesondere auch bei wenigstens 300°C oder wenigstens 700°C. Insbesondere kann der Ofenraum auf eine Temperatur im Bereich von 300 bis 1.200°C, im Bereich von 700 bis 1.200°C, im Bereich von 300 bis 1.000°C und besondersThe heated gas introduced into the furnace space through the gas inlets can be used to heat the furnace space to a desired temperature. In particular, the furnace chamber is heated to the desired temperature for the heat treatment of the products contained in the kiln furniture. The tunnel furnace according to the invention is also particularly suitable for the heat treatment of products at high temperatures, in particular also at at least 300°C or at least 700°C. In particular, the furnace chamber can be heated to a temperature in the range from 300 to 1200°C, in the range from 700 to 1200°C, in the range from 300 to 1000°C and in particular

bevorzugt im Bereich von 700 bis 1.000°C erhitzt werden. Soweit der erfindungsgemäße Tunnelofen zur Wärmebehandlung von Produkten in Form von Kathodenmaterial, insbesondere zur Synthese von pulverförmigen Kathodenmaterial verwendet wird, kann vorgesehen sein, dass der Ofenraum auf eine Temperatur im Bereich von 1.000 bis 1.200°C erhitzt wird.preferably in the range of 700 to 1000°C. If the tunnel furnace according to the invention is used for the heat treatment of products in the form of cathode material, in particular for the synthesis of powdery cathode material, it can be provided that the furnace chamber is heated to a temperature in the range from 1000 to 1200°C.

Nach einer besonders bevorzugten Ausführungsform ist vorgesehen, dass unterhalb der Brennhilfsmittel ein Gasverteilraum ausgebildet ist. Dieser Gasverteilraum dient insbesondere dazu, Brenngas unterhalb der Brennhilfsmittel gleichmäßig zu verteilen, so dass das vergleichmäßigte Gas vom Gasverteilraum anschließend vertikal zwischen den Brennhilfsmitteln aufsteigen kann. Hierdurch können die in den Brennhilfsmitteln befindlichen Produkte sehr gleichmäßig mit Brenngas und damit mit Wärme beaufschlagt werden. Um einen solchen Gasverteilraum unterhalb der Brennhilfsmittel auszubilden, können die Brennhilfsmittel bevorzugt auf voneinander beabstandeten Auflagen aufliegen, wobei die Auflagen bevorzugt auf den Ofenwagen aufliegen. Bei den Auflagen kann es sich bevorzugt um keramische, insbesondere feuerfeste keramische Steine handeln. Der Gasverteilraum ist bevorzugt zwischen der Oberseite der Ofenwagen und den Brennhilfsmitteln ausgebildet.According to a particularly preferred embodiment, it is provided that a gas distribution space is formed below the kiln furniture. This gas distribution space is used in particular to distribute fuel gas evenly underneath the kiln furniture, so that the equalized gas can then rise vertically from the gas distribution space between the kiln furniture. As a result, the products in the kiln furniture can be supplied with fuel gas and thus with heat very evenly. In order to form such a gas distribution space below the kiln furniture, the kiln furniture can preferably rest on supports that are spaced apart from one another, the supports preferably resting on the kiln cars. The supports can preferably be ceramic, in particular refractory ceramic bricks. The gas distribution space is preferably formed between the top of the kiln car and the kiln furniture.

Besonders bevorzugt ist Gas über die Gaseinlässe in diesen Gasverteilraum einleitbar. Besonders bevorzugt ist Gas über die oben bezeichneten Gaseinlässe, über die Gas unterhalb der Brennhilfsmittel in den Ofenraum einleitbar ist, in den Gasverteilraum einleitbar.Gas can particularly preferably be introduced into this gas distribution space via the gas inlets. Gas can particularly preferably be introduced into the gas distribution space via the above-mentioned gas inlets, via which gas can be introduced into the furnace space below the kiln furniture.

Die Brennhilfsmittel sind unter Ausbildung wenigstens eines vertikalen Spaltes zwischen den Brennhilfsmitteln auf den Ofenwagen angeordnet. Durch diese, zwischen den Brennhilfsmitteln verlaufenden, vertikalen Spalte können Gase zwischen den Brennhilfsmitteln vertikal aufwärts bis an die Ofendecke strömen. Besonders bevorzugt verläuft wenigstens einer der wenigstens einen vertikalen Spalte zwischen den Brennhilfsmitteln in Transportrichtung. Bevorzugt laufen mehrere der vertikalen Spalte in Transportrichtung. Erfindungsgemäß wurde erkannt, dass durch solche vertikal in Transportrichtung verlaufenden Spalte zwischen den Brennhilfsmitteln nicht nur eine vertikal aufwärts gerichtete Strömung der Gase im Ofenraum erzeugt, sondern gleichzeitig auch eine Gasströmung von Gasen im Ofenraum in Transportrichtung besonders wirksam unterdrückt werden kann.The kiln furniture is arranged on the kiln car, forming at least one vertical gap between the kiln furniture. Through this, running between the kiln furniture, vertical column gases between the kiln furniture can vertically upwards to the pour oven cover. At least one of the at least one vertical gaps between the kiln furniture particularly preferably runs in the transport direction. Several of the vertical gaps preferably run in the transport direction. According to the invention, it was recognized that such gaps between the kiln furniture running vertically in the direction of transport not only generate a vertically upward flow of gases in the furnace space, but also at the same time a gas flow of gases in the furnace space in the direction of transport can be particularly effectively suppressed.

Um vertikale Spalte zwischen den Brennhilfsmitteln auszubilden, können die Brennhilfsmittel horizontal beabstandet voneinander auf den Ofenwagen angeordnet sein. Besonders bevorzugt sind die Brennhilfsmittel quer zur Transportrichtung beabstandet voneinander unter Ausbildung wenigstens eines vertikalen Spaltes zwischen den Brennhilfsmitteln auf den Ofenwagen angeordnet, um hierdurch wenigstens einen Spalt zwischen den Brennhilfsmitteln in Transportrichtung auszubilden.In order to form vertical gaps between the kiln furniture, the kiln furniture can be arranged on the kiln car at a horizontal distance from one another. Particularly preferably, the kiln furniture are spaced apart from one another transversely to the transport direction, forming at least one vertical gap between the kiln furniture on the kiln car, in order to form at least one gap between the kiln furniture in the transport direction.

Kumulativ können ferner vertikale Spalte quer zur Transportrichtung zwischen den Brennhilfsmitteln ausgebildet sein, wozu die Brennhilfsmittel längs zur Transportrichtung beabstandet voneinander unter Ausbildung wenigstens eines vertikalen Spaltes zwischen den Brennhilfsmitteln auf den Ofenwagen angeordnet sein können.Cumulatively, vertical gaps can also be formed transversely to the transport direction between the kiln furniture, for which purpose the kiln furniture can be spaced apart from one another along the transport direction, forming at least one vertical gap between the kiln furniture on the kiln car.

Nach einer besonders bevorzugten Ausführungsform sind stapelbare Brennhilfsmittel, insbesondere übereinander stapelbare Brennhilfsmittel, besonders bevorzugt vertikal übereinander stapelbare Brennhilfsmittel vorgesehen. Nach einer besonders bevorzugten Ausführungsform sind Brennhilfsmittel in Form von Kassetten vorgesehen, also in Form von "Kisten", insbesondere mit einer (in Aufsicht) rechteckigen Außenkontur. Insbesondere, soweit die Brennhilfsmittel in Form von solchen Kassetten, insbesondere mit einer rechteckigen Außenkontur, vorliegen, lassen sich die Brennhilfsmittel besonders einfach und effektiv derart nebeneinander auf den Ofenwagen anordnen, dass zwischen den Brennhilfsmitteln vertikal verlaufende Spalte ausbildbar sind.According to a particularly preferred embodiment, kiln furniture that can be stacked, in particular kiln furniture that can be stacked on top of one another, particularly preferably kiln furniture that can be stacked vertically on top of one another, is provided. According to a particularly preferred embodiment, kiln furniture is provided in the form of cassettes, that is to say in the form of "boxes", in particular with a rectangular outer contour (in plan). In particular, if the kiln furniture is in the form of such cassettes, in particular with a rectangular outer contour, the kiln furniture can be arranged next to one another on the kiln car in a particularly simple and effective manner in such a way that vertical gaps can be formed between the kiln furniture.

Zum Transport der Produkte durch den Ofenraum, sind die Produkte durch die Brennhilfsmittel aufgenommen. Soweit Produkte in Form von pulverförmigen Produkten vorliegen, sind die Pulver in die Brennhilfsmittel aufgenommen, also im Fall von Brennhilfsmitteln in Form von Kassetten oder Kisten in die Kassetten beziehungsweise Kisten aufgenommen.To transport the products through the furnace chamber, the products are picked up by the kiln furniture. If products are in the form of powdered products, the powders are included in the kiln furniture, ie in the case of kiln furniture in the form of cassettes or boxes, they are included in the cassettes or boxes.

Die Brennhilfsmittel bestehen bevorzugt aus Graphit oder Keramik, beispielsweise aus einer Oxidkeramik oder einer Nichtoxidkeramik, besonders bevorzugt aus einer Nichtoxidkeramik, insbesondere einer nitridischen oder carbidischen Nichtoxidkeramik, besonders bevorzugt aus SiC, insbesondere silikatisch beziehungsweise keramisch gebundenem SiC.The firing aids preferably consist of graphite or ceramic, for example an oxide ceramic or a non-oxide ceramic, particularly preferably a non-oxide ceramic, in particular a nitridic or carbidic non-oxide ceramic, particularly preferably SiC, in particular silicate or ceramic bonded SiC.

Um auch im Fall vertikal übereinander gestapelter Brennhilfsmittel eine Beaufschlagung der in den Brennhilfsmitteln aufgenommenen Produkte mit den heißen Ofengasen zu ermöglichen, kann bevorzugt vorgesehen sein, dass die Brennhilfsmittel derart vertikal übereinander gestapelt sind, dass ein durchströmbarer Durchlass zwischen vertikal benachbarten Brennhilfsmitteln ausgebildet ist. Soweit die Brennhilfsmittel in Form von Kassetten ausgebildet sind, kann beispielsweise vorgesehen sein, dass diese Kassetten in ihrem unteren Bereich jeweils geschlossenen Wände aufweisen, so dass pulverförmige Produkte sicher in den Kassetten aufgenommen werden können, und die Wände der Kassetten in ihrem oberen Bereich Durchbrechungen, Löcher oder sonstige Öffnungen aufweisen, durch die Brenngase zwischen vertikal benachbarten Kassetten hindurchströmen können.In order to enable the products held in the kiln furniture to be exposed to the hot furnace gases even when kiln furniture is stacked vertically one above the other, it can preferably be provided that the kiln furniture is stacked vertically one above the other in such a way that a passage through which a flow can flow is formed between vertically adjacent kiln furniture. If the kiln furniture is in the form of cassettes, provision can be made, for example, for these cassettes to have closed walls in their lower area, so that powdery products can be safely accommodated in the cassettes, and for the walls of the cassettes to have openings in their upper area, Have holes or other openings through which combustion gases can flow between vertically adjacent cassettes.

Die Ofenwagen können gemäß dem Stand der Technik ausgebildet sein. Insoweit können die Ofenwagen beispielsweise auf Schienen durch den Ofenraum fahrbar sein. Zur Bewegung der Ofenwagen können diese beispielsweise mittels Seilzügen oder dergleichen mechanische Antriebsmittel bewegbar sein. Die Ofenwagen können (in Draufsicht) eine im Wesentlichen rechteckige Außenkontur aufweisen.The kiln cars can be designed according to the prior art. In this respect, the kiln cars can be moved through the kiln chamber on rails, for example. To move the kiln cars, they can be moved, for example, by means of cable pulls or similar mechanical drive means. The kiln cars can (in top view) have an essentially rectangular outer contour.

Die Ofenwagen weisen jeweils eine Oberseite auf, auf der die Brennhilfsmittel anordenbar sind. Bevorzugt sind die Brennhilfsmittel auf die Oberseite der Ofenwagen auflegbar. Bevorzugt ist die Oberseite der Ofenwagen als eine ebene Fläche ausgebildet, bevorzugt mit einer rechteckigen Außenkontur.The kiln cars each have an upper side on which the kiln furniture can be arranged. The kiln furniture can preferably be placed on top of the kiln cars. The upper side of the kiln car is preferably designed as a flat surface, preferably with a rectangular outer contour.

Bevorzugt begrenzen die Oberseiten der Ofenwagen den Ofenraum unterseitig, bildet also den Ofenboden.The tops of the kiln cars preferably delimit the bottom of the kiln space, ie they form the kiln floor.

Bevorzugt ist der Tunnelofen gasdicht abgedichtet. Bevorzugt kann hierzu vorgesehen sein, dass der Tunnelofen außenseitig von einem gasdichten Mantel gebildet ist, bevorzugt von einem gasdichten Stahlgehäuse. Besonders bevorzugt umschließt das gasdichte Stahlgehäuse auch die im Ofenraum befindlichen Ofenwagen. Damit umschließt das gasdichte Stahlgehäuse insbesondere auch die Ofendecke, die Ofenwände und die Ofenwagen. Bevorzugt verläuft das gasdichte Stahlgehäuse unterhalb der Ofenwagen, so dass auch die Ofenwagen gasdicht umschlossen sind.The tunnel furnace is preferably sealed in a gas-tight manner. For this purpose, it can preferably be provided that the outside of the tunnel furnace is formed by a gas-tight jacket, preferably by a gas-tight steel housing. The gas-tight steel housing particularly preferably also encloses the kiln cars located in the kiln space. The gas-tight steel housing thus also encloses the kiln roof, the kiln walls and the kiln cars. The gas-tight steel housing preferably runs below the kiln cars, so that the kiln cars are also enclosed in a gas-tight manner.

Um den Tunnelofen am ersten Ende des Ofenraums, also am Ofeneinlass, und am zweiten Ende des Ofenraums, also am Ofenauslass, gasdicht abzudichten, können Verschlussmittel vorgesehen sein, durch die der Ofenraum gasdicht verschließbar ist, die jedoch ein Einfahren beziehungsweise Ausfahren von Ofenwagen in beziehungsweise aus dem Ofenraum ermöglichen. Bevorzugt können hierzu Schleusen am ersten Ende und zweiten Ende vorgesehen sein. Durch entsprechende Schleusen jeweils am ersten Ende und zweiten Ende des Ofenraums können Ofenwagen in den Ofenraum eingefahren beziehungsweise wieder aus diesem ausgefahren werden, und gleichzeitig der Ofenraum permanent gasdicht umschlossen bleiben.In order to seal the tunnel furnace gas-tight at the first end of the furnace space, i.e. at the furnace inlet, and at the second end of the furnace space, i.e. at the furnace outlet, closure means can be provided by which the furnace space can be closed in a gas-tight manner, but which prevent Allow kiln cars in and out of the kiln room. For this purpose, locks can preferably be provided at the first end and the second end. Appropriate locks at the first end and second end of the furnace chamber allow kiln cars to be moved into and out of the furnace chamber, and at the same time the furnace chamber remains permanently enclosed in a gas-tight manner.

Der besondere Vorteil eines solchen gasdichten Tunnelofens besteht insbesondere darin, dass eine gewünschte Ofenatmosphäre eingestellt werden kann.The particular advantage of such a gas-tight tunnel kiln is, in particular, that a desired kiln atmosphere can be set.

Besonders bevorzugt herrscht im Ofenraum eine oxidische Ofenatmosphäre beziehungsweise wird der erfindungsgemäße Tunnelofen mit einer oxidischen Ofenatmosphäre betrieben. Es kann jedoch auch vorgesehen sein, den Tunnelofen mit einer reduzierenden Ofenatmosphäre zu betreiben, beispielsweise wenn Brennhilfsmittel aus Graphit vorgesehen sind.An oxidic furnace atmosphere particularly preferably prevails in the furnace chamber or the tunnel furnace according to the invention is operated with an oxidic furnace atmosphere. However, it can also be provided to operate the tunnel kiln with a reducing kiln atmosphere, for example if kiln furniture made of graphite is provided.

Bevorzugt liegt der Anteil an Sauerstoffgas in der Ofenatmosphäre über 95 Volumen-%. Es kann jedoch auch vorgesehen sein, den Ofen mit Luftatmosphäre, also einem Anteil an Sauerstoffgas von etwa 21 Volumen-% zu betreiben. Soweit der Tunnelofen mit einer reduzierenden Ofenatmosphäre betrieben wird, kann der Ofen beispielsweise mit Stickstoff als Prozessgas betrieben werden und beispielsweise mit einem Anteil an Restsauerstoff unter 100ppm.The proportion of oxygen gas in the furnace atmosphere is preferably more than 95% by volume. However, provision can also be made for the furnace to be operated with an air atmosphere, ie with an oxygen gas content of approximately 21% by volume. If the tunnel kiln is operated with a reducing kiln atmosphere, the kiln can be operated, for example, with nitrogen as the process gas and, for example, with a proportion of residual oxygen below 100 ppm.

Ein besonderer Vorteil des erfindungsgemäßen Tunnelofens besteht insbesondere auch darin, dass dieser praktisch in einer beliebigen Länge (in Transportrichtung) zur Verfügung gestellt werden kann, insbesondere auch mit einer Länge über 50 m. Nach einer bevorzugten Ausführungsform ist vorgesehen, dass der Tunnelofen eine Länge von wenigstens 120 m, insbesondere von wenigstens 150 m aufweist. Insoweit kann der Tunnelofen beispielsweise in Länge im Bereich von 50 - 250 m aufweisen. Bevorzugt weist der Tunnelofen eine Länge im Bereich von 120 - 250 m, noch bevorzugter im Bereich von 150 - 250 m und noch bevorzugter im Bereich von 150 - 200 m auf.A particular advantage of the tunnel kiln according to the invention is, in particular, that it can be made available in practically any length (in the transport direction), in particular with a length of more than 50 m at least 120 m, in particular of at least 150 m. In this respect, the tunnel kiln can have a length in the range of 50-250 m, for example. The tunnel kiln preferably has a length in the range of 120-250 m, more preferably in the range of 150-250 m and even more preferably in the range of 150-200 m.

Gegenstand der Erfindung ist auch ein Verfahren zum Betreiben eines Tunnelofens, welches die folgenden Schritte umfasst:

  • Zur Verfügungstellung eines erfindungsgemäßen Tunnelofens; gemäß einem der Ansprüche 1-11;
  • Fahren der Ofenwagen entlang der Transportrichtung durch den Ofenraum;
  • Ausleiten von im Ofenraum befindlichem Gas über die Gasauslässe;
  • Einleiten von Gas in den Ofenraum über die Gaseinlässe; und
  • Beheizen des Ofenraums über die Heizelemente.
The invention also relates to a method for operating a tunnel kiln, which comprises the following steps:
  • Providing a tunnel kiln according to the invention; according to any one of claims 1-11;
  • driving the kiln cars along the transport direction through the kiln room;
  • discharging gas in the furnace space via the gas outlets;
  • introducing gas into the furnace space via the gas inlets; and
  • Heating of the oven chamber via the heating elements.

Im Übrigen kann das erfindungsgemäße Verfahren die hierin beschriebenen Maßgaben zum Betreiben des erfindungsgemäßen Tunnelofens umfassen. Gegenstand der Erfindung ist auch die Verwendung eines erfindungsgemäßenOtherwise, the method according to the invention can include the stipulations described herein for operating the tunnel kiln according to the invention. The subject matter of the invention is also the use of a device according to the invention

Tunnelofens gemäß einem der Ansprüche 1-11 zur Wärmebehandlung von Produkten in Form von Pulver. Bevorzugt erfolgt die Verwendung mit der Maßgabe, dass der Tunnelofen zur Wärmebehandlung von Produkten in Form von pulverförmigem Kathodenmaterial, insbesondere zur Synthese von pulverförmigem Kathodenmaterial erfolgt.Tunnel kiln according to any one of claims 1-11 for heat treatment of products in the form of powder. It is preferably used with the proviso that the tunnel furnace is used for the heat treatment of products in the form of powdered cathode material, in particular for the synthesis of powdered cathode material.

Im Übrigen kann die Verwendung mit den hierin beschriebenen Maßgaben zum Betreiben des erfindungsgemäßen Tunnelofens erfolgen.Otherwise, it can be used with the stipulations described herein for operating the tunnel kiln according to the invention.

Weitere Merkmale der Erfindung ergeben sich aus den Ansprüchen, den Figuren sowie der zugehörigen Figurenbeschreibung.Further features of the invention result from the claims, the figures and the associated description of the figures.

Sämtliche Merkmale der Erfindung können, einzeln oder in Kombination, beliebig miteinander kombiniert sein.All of the features of the invention can be combined with one another as desired, individually or in combination.

Ein Ausführungsbeispiel der Erfindung wird mittels der nachfolgenden Figurenbeschreibung näher erläutert.An exemplary embodiment of the invention is explained in more detail by means of the following description of the figures.

Dabei zeigt,

Figur 1
eine Ansicht auf einen Querschnitt eines Ausführungsbeispiels eines erfindungsgemäßen Tunnelofens senkrecht zur Längsachse des Tunnelofens;
Figur 2
eine Ansicht auf einen Abschnitt eines Querschnitts des Tunnelofens nach Figur 1 parallel zur Längsachse; und
Figur 3
eine Ansicht auf einen Querschnitts des Tunnelofens nach Figur 1 parallel zur Längsachse.
It shows
figure 1
a view of a cross section of an embodiment of a tunnel kiln according to the invention perpendicular to the longitudinal axis of the tunnel kiln;
figure 2
Figure 12 shows a view of a portion of a cross section of the tunnel kiln figure 1 parallel to the longitudinal axis; and
figure 3
a view of a cross section of the tunnel kiln figure 1 parallel to the longitudinal axis.

Die Darstellungen in den Figuren sind hinsichtlich der Gestaltung und Dimensionierung des Tunnelofens stark schematisiert.The representations in the figures are highly schematic with regard to the design and dimensioning of the tunnel kiln.

Figur 1 zeigt eine Ansicht auf einen Querschnitt des Tunnelofens senkrecht zur Transportrichtung beziehungsweise Längsachse des Tunnelofens, wobei der Tunnelofen in seiner Gesamtheit mit dem Bezugszeichen 1 gekennzeichnet ist. Die Transportrichtung und Längsachse des Tunnelofens 1 verlaufen in Figur 1 senkrecht zur Zeichenebene. Die Längsachse ist in den Figuren 2 und 3 mit L bezeichnet, wobei die Transportrichtung entlang der Längsachse L in den Figuren 2 und 3 nach rechts verläuft. Der Tunnelofen 1 umfasst einen tunnelartigen Ofenraum 2, der sich senkrecht zur Zeichenebene von einem ersten Ende (vor der Zeichenebene) zu einem zweiten Ende (hinter der Zeichenebene) des Ofenraums 2 erstreckt, wobei der Ofenraum 2 oberseitig durch eine Ofendecke 3 und seitlich durch eine erste, in Figur 1 linke, Ofenwand 4 und eine zweite, in Figur 1 rechte, Ofenwand 5 begrenzt ist. Der Tunnelofen 1 umfasst ferner Ofenwagen 6, die über Räder 7 auf Schienen 8 entlang der Transportrichtung, also in Figur 1 senkrecht zur Zeichenebene und in den Figuren 2 und 3 nach rechts, durch den Ofenraum 2 fahrbar sind. Auf den Ofenwagen 6 sind Brennhilfsmittel 9 zur Aufnahme von Produkten angeordnet. figure 1 shows a view of a cross section of the tunnel kiln perpendicular to the transport direction or longitudinal axis of the tunnel kiln, the tunnel kiln being identified in its entirety with the reference numeral 1. The transport direction and longitudinal axis of the tunnel kiln 1 run in figure 1 perpendicular to the drawing plane. The long axis is in the figures 2 and 3 denoted by L, the transport direction along the Longitudinal axis L in the figures 2 and 3 runs to the right. The tunnel kiln 1 comprises a tunnel-like kiln chamber 2, which extends perpendicular to the plane of the drawing from a first end (in front of the plane of the drawing) to a second end (behind the plane of the drawing) of the kiln chamber 2, with the kiln chamber 2 being covered on the top by a kiln ceiling 3 and on the side by a first, in figure 1 left, oven wall 4 and a second, in figure 1 right, furnace wall 5 is limited. The tunnel kiln 1 also includes kiln cars 6, which are mounted on wheels 7 on rails 8 along the transport direction, i.e. in figure 1 perpendicular to the plane and in the figures 2 and 3 to the right, through furnace room 2. Kiln furniture 9 for receiving products are arranged on the kiln car 6 .

Die Ofendecke 3 ist aus feuerfesten keramischen Steinen gemauert. Gleichmäßig voneinander beabstandet sind in der Mitte der Ofendecke 3 Gasauslässe 10 in Form von durch die Ofendecke 3 hindurchgehenden Öffnungen angeordnet, von denen in den Figuren ein solcher Gasauslass 10 zu erkennen ist. Die Gasauslässe 10 sind gleichmäßig voneinander beabstandet entlang der Transportrichtung an der Ofendecke 3 angeordnet. Die Gasauslässe 10 führen zu einem von einem Motor 11 angetriebenen Gebläse 12.The furnace roof 3 is made of refractory ceramic bricks. Arranged at equal distances from one another in the center of the furnace roof 3 are gas outlets 10 in the form of openings passing through the furnace roof 3, of which one such gas outlet 10 can be seen in the figures. The gas outlets 10 are arranged at a uniform distance from one another along the transport direction on the furnace roof 3 . The gas outlets 10 lead to a fan 12 driven by a motor 11.

Die vertikal verlaufenden Ofenwände 4, 5 sind aus feuerfesten keramischen Steinen gemauert. In den Seitenwänden 4, 5 sind Gaseinlässe 17, 18, 19 in Form von durch die Ofenwände 4, 5 hindurchgehenden Öffnungen vorgesehen. Die Gaseinlässe 17, 18, 19 sind entlang der Transportrichtung gleichmäßig voneinander über die Ofenlänge beabstandet in verschiedenen Höhen an den Ofenwänden 4, 5 angeordnet. Dabei sind jeweils an den Seitenwänden 4, 5 gegenüberliegende untere Gaseinlässe 17, darüber angeordnete Gaseinlässe 18 und wiederum darüber angeordnete Gaseinlässe 19 an den Seitenwänden 4, 5 angeordnet. Die untersten Gaseinlässe 17 sind derart angeordnet, dass über dieses Gas unterhalb der Brennhilfsmittel 9 in den Ofenraum 2 einleitbar ist. Dabei ist, wie unten weiter im Detail ausgeführt, über diese untersten Gaseinlässe 17 Gas in einen unterhalb der Brennhilfsmittel 9 ausgebildeten Gasverteilraum 20 einleitbar, angedeutet durch die Pfeile P1. Über die Gaseinlässe 17, 18, 19 ist Gas jeweils horizontal in den Ofenraum 2 einleitbar, wobei über die unteren Gaseinlässe 17 Gas mit einer höheren Geschwindigkeit in den Ofenraum 2 einleitbar ist als durch die darüber angeordneten Gaseinlässe 18, 19.The vertical furnace walls 4, 5 are made of refractory ceramic bricks. In the side walls 4, 5 gas inlets 17, 18, 19 are provided in the form of openings passing through the furnace walls 4, 5. The gas inlets 17, 18, 19 are arranged at different heights on the furnace walls 4, 5 along the direction of transport, spaced evenly apart from one another over the length of the furnace. In this case, lower gas inlets 17 located opposite one another on the side walls 4, 5, gas inlets 18 arranged above them and gas inlets 19 arranged above them in turn are arranged on the side walls 4, 5. The lowest gas inlets 17 are arranged in such a way that this gas can be introduced below the kiln furniture 9 into the furnace space 2 . As explained in more detail below, gas can be introduced via these lowermost gas inlets 17 into a gas distribution space 20 formed below the kiln furniture 9, indicated by the arrows P1. Gas can be introduced horizontally into the furnace chamber 2 via the gas inlets 17, 18, 19, with gas being able to be introduced into the furnace chamber 2 at a higher speed via the lower gas inlets 17 than through the gas inlets 18, 19 arranged above.

Die feuerfesten keramischen Steine der Ofendecke 6 und der Ofenwände 4, 5 sind hochtonerdehaltige Steine mit einem Gehalt an Al2O3 von über 99 Masse- %, bezogen auf die Masse der Steine.The refractory ceramic bricks of the furnace roof 6 and the furnace walls 4, 5 are high-alumina bricks with an Al 2 O 3 content of more than 99% by mass, based on the mass of the bricks.

Der Tunnelofen 1 ist außenseitig von einem Stahlgehäuse 27 gebildet, der den Tunnelofen 1 gasdicht nach außen abdichtet. Das Stahlgehäuse 27 weist eine im wesentlichen rechteckige Kontur mit einer horizontal verlaufenden Decke 27.1, einem horizontal verlaufenden Boden 27.2 und zwei jeweils vertikal verlaufenden Wänden 27.3, 27.4 auf. Unterhalb der Decke 27.1 des Stahlmantels 27 ist eine Hängedecke 16 aus feuerfesten keramischen Steinen an der Decke 27.1 aufgehängt, die oberhalb der Ofendecke 3 mit Abstand zu dieser verläuft. Hierdurch ist oberhalb der Ofendecke 3 ein Freiraum 13 zwischen der Ofendecke 3 und der Hängedecke 16 ausgebildet.The tunnel kiln 1 is formed on the outside by a steel housing 27 which seals the tunnel kiln 1 gas-tight to the outside. The steel housing 27 has an essentially rectangular contour with a horizontally extending ceiling 27.1, a horizontally extending floor 27.2 and two vertical walls 27.3, 27.4. Below the ceiling 27.1 of the steel jacket 27, a suspended ceiling 16 made of refractory ceramic bricks is suspended from the ceiling 27.1, which runs above the furnace ceiling 3 at a distance from it. As a result, a free space 13 is formed between the furnace ceiling 3 and the suspended ceiling 16 above the furnace ceiling 3 .

Die zwei Wände 27.3, 27.4 des Stahlmantels 27 sind innenseitig mit einer Verkleidung aus feuerfesten Steinen 14, 15 zugestellt, die auf Höhe der Seitenwände 4, 5 bis an die Seitenwände 4, 5 heranreicht. Die Verkleidung aus feuerfesten Steinen 14, 15 weist vertikal verlaufende Öffnungen 28 auf, die sich mit Abstand zueinander zwischen den Wänden 27.3, 27.4 und den Seitenwänden 4, 5 erstrecken. Die Gaseinlässe 17, 18, 19 erstrecken sich jeweils durch die Seitenwände 4, 5 vom Ofenraum 2 bis in diese Öffnungen 28.The two walls 27.3, 27.4 of the steel jacket 27 are lined on the inside with a covering of refractory bricks 14, 15, which reaches up to the side walls 4, 5 at the level of the side walls 4, 5. The lining of refractory bricks 14,15 has vertically extending openings 28 which extend at a distance from one another between the walls 27.3,27.4 and the side walls 4,5. The gas inlets 17, 18, 19 extend each through the side walls 4, 5 from the furnace chamber 2 to these openings 28.

Der Freiraum 13 und die Öffnungen 28 bilden zusammen Gasleitungen, durch die Gas leitbar ist.The space 13 and the openings 28 together form gas lines through which gas can be conducted.

Durch die Hängedecke 16 sind Abgasleitungen 31 geführt, die an ihrem einen Ende in den Freiraum 13 und an ihrem anderen Ende in Ventile 33 in der Decke 27.1 münden.Through the suspended ceiling 16 exhaust gas lines 31 are guided, which open at one end into the free space 13 and at the other end into valves 33 in the ceiling 27.1.

Ferner sind durch die Verkleidungen 14, 15 Frischgasleitungen 32 geführt, die an ihrem einen Ende in die Öffnungen 28 und an ihrem anderen Ende in Ventile 34 in den Wänden 27.3, 27.4 münden.Furthermore, fresh gas lines 32 are passed through the panels 14, 15, which open at one end into the openings 28 and at the other end into valves 34 in the walls 27.3, 27.4.

Vertikal angeordnete, elektrische Heizelemente 21 erstrecken sich von der Hängedecke 16 durch den Freiraum 13 und durch die Öffnungen 28. Bei den elektrischen Heizelementen 21 handelt es sich um keramische Heizelemente aus SiC.Vertically disposed electrical heating elements 21 extend from the false ceiling 16 through the void 13 and through the openings 28. The electrical heating elements 21 are SiC ceramic heating elements.

Die Ofenwagen 6 sind im Wesentlichen gemäß dem Stand der Technik ausgebildet. Insoweit sind die Ofenwagen 6 über Räder 7 auf Schienen 8 entlang der Transportrichtung verfahrbar, wobei sie über (nicht dargestellte) Seilzüge bewegbar sind. Die Ofenwagen 6 weisen eine (in Aufsicht) im Wesentlichen rechteckige Außenkontur auf. Die Oberseite 22 der Ofenwagen 6 ist als ebene Fläche ausgebildet und begrenzt den Ofenraum 2 unterseitig. Zur Seite hin sind die Ofenwagen 6 jeweils über einen Labyrinthverschluss 23 gegenüber dem Fundament 24 der Verkleidungen 14, 15 des Tunnelofens 1 abgedichtet.The kiln cars 6 are designed essentially according to the prior art. In this respect, the kiln cars 6 can be moved along the transport direction via wheels 7 on rails 8, and they can be moved via cables (not shown). The kiln cars 6 have a (viewed from above) essentially rectangular outer contour. The top 22 of the kiln car 6 is designed as a flat surface and delimits the kiln chamber 2 on the underside. To the side, the kiln cars 6 are each sealed off from the foundation 24 of the panels 14 , 15 of the tunnel kiln 1 via a labyrinth seal 23 .

Die Oberseite 22 der Ofenwagen 6 dient als Auflage für die Brennhilfsmittel 9. Dabei sind die Brennhilfsmittel 9 über Auflagen 25 in Form von feuerfesten keramischen Steinen mit Abstand zur Oberseite 22 der Ofenwagen 6 auf diese aufgelegt. Hierdurch ist zwischen den Ofenwagen 6 und den Brennhilfsmitteln 9 der Gasverteilraum 20 ausgebildet.The top 22 of the kiln car 6 serves as a support for the kiln cars 9. The kiln cars 9 are placed on top 22 of the kiln cars 6 by means of supports 25 in the form of refractory ceramic bricks at a distance from them. As a result, the gas distribution space 20 is formed between the kiln car 6 and the kiln furniture 9 .

Die Brennhilfsmittel 9 bestehen aus vertikal übereinander stapelbaren Kassetten aus keramisch gebundenem SiC. Die Brennhilfsmittel 9 weisen eine (in Aufsicht) rechteckige Außenkontur auf. In ihrem unteren Bereich weisen die Brennhilfsmittel 9 geschlossene Wände und in ihrem oberen Bereich Durchbrechungen auf, so dass zwischen vertikal benachbarten, übereinander gestapelten Brennhilfsmitteln 9 ein durchströmbarer Durchlass verbleibt.The firing aids 9 consist of cassettes made of vitrified SiC that can be stacked vertically one on top of the other. The firing aids 9 have a rectangular outer contour (in plan view). The kiln furniture 9 has closed walls in its lower region and openings in its upper region, so that a passage through which a flow can flow remains between vertically adjacent kiln furniture 9 stacked on top of one another.

Im Ausführungsbeispiel sind jeweils acht Brennhilfsmittel 9 übereinander gestapelt. Die Stapel sind jeweils in Reihen in Transportrichtung auf den Ofenwagen 6 angeordnet. Dabei sind drei dieser Reihen quer zur Transportrichtung derart nebeneinander angeordnet, dass zwischen benachbarten Reihen der übereinander gestapelten Brennhilfsmitteln 9 jeweils ein vertikaler Spalt 26 zwischen den Brennhilfsmitteln 9 verbleibt.In the exemplary embodiment, eight kiln furniture 9 are stacked one on top of the other. The stacks are each arranged in rows on the kiln car 6 in the transport direction. Three of these rows are arranged next to one another transversely to the transport direction in such a way that a vertical gap 26 remains between the kiln furniture 9 in each case between adjacent rows of the kiln furniture 9 stacked on top of one another.

In den Brennhilfsmitteln 9 ist jeweils pulverförmiges Kathodenmaterial angeordnet.Powdered cathode material is arranged in each of the kiln furniture 9 .

Am ersten, in Figur 3 linken Ende des Ofenraum 2 weist der Tunnelofen 1 eine Einlaufschleuse 29 und am zweiten, in Figur 3 rechten Ende des Ofenraums 2 eine Auslaufschleuse 30 zur gasdichten Abdichtung des Ofenraums 2 nach dem Stand der Technik auf. Die Einlaufschleuse 29 und die Auslaufschleuse 30 ermöglichen ein Ein- und Ausfahren von Ofenwagen 6 in und aus dem Ofenraum 2, wobei der Ofenraum 2 jedoch gleichzeitig gasdicht abgeschlossen werden kann.On the first, in figure 3 left end of the furnace chamber 2, the tunnel furnace 1 has an inlet lock 29 and on the second, in figure 3 Right end of the furnace chamber 2 an outlet lock 30 for gas-tight sealing of the furnace chamber 2 according to the prior art. The inlet sluice 29 and the outlet sluice 30 allow kiln cars 6 to be moved in and out of the kiln space 2, with the kiln space 2 being able to be sealed gas-tight at the same time.

Der Tunnelofen 1 weist in Transportrichtung eine Länge von etwa 150 m auf.The tunnel kiln 1 has a length of about 150 m in the transport direction.

In der praktischen Anwendung wird der in den Figuren dargestellte Tunnelofen 1 wie folgt betrieben:
Die Ofenwagen 6 werden durch die Einlaufschleuse 29 in den Ofenraum 2 eingeschoben, anschließend kontinuierlich in Transportrichtung entlang der Längsachse L durch den Ofenraum 2 bewegt und nach der Ofenreise durch die am zweiten Ende des Ofenraums 2 befindliche Auslaufschleuse 30 wieder aus dem Ofenraum 2 ausgefahren.In practical application, the tunnel kiln 1 shown in the figures is operated as follows:
The kiln cars 6 are pushed into the furnace chamber 2 through the inlet lock 29, then moved continuously in the direction of transport along the longitudinal axis L through the furnace chamber 2 and, after the furnace journey, are removed again from the furnace chamber 2 through the outlet lock 30 located at the second end of the furnace chamber 2.

Das im Ofenraum 2 befindliche Gas wird über die Gasauslässe 10 aus dem Ofenraum 2 ausgeleitet. Dieses Ausleiten von Gas aus dem Ofenraum 2 über die Gasauslässe 10 wird durch das über den Motor 11 angetriebene Gebläse 12 unterstützt, das die Ofengase nach Ausleiten aus den Gasauslässen 10 zunächst in den Freiraum 13 (angedeutet durch die Pfeile P3), weiter zu den keramischen Heizelementen 21 und an diesen entlang, weiter durch die Öffnungen 28 und schließlich durch die Gaseinlässe 17, 18, 19 zurück in den Ofenraum 2 fördert. Während des Entlangleitens an den keramischen Heizelementen 21 wird das Ofengas erhitzt, so dass das entsprechend erhitze Gas über die Gaseinlässe 17, 18, 19 anschließend wieder in den Ofenraum 2 eingeleitet wird, angedeutet durch die Pfeile P1.The gas in the furnace chamber 2 is discharged from the furnace chamber 2 via the gas outlets 10 . This discharge of gas from the furnace chamber 2 via the gas outlets 10 is supported by the fan 12 driven by the motor 11, which, after discharge from the gas outlets 10, first blows the furnace gases into the free space 13 (indicated by the arrows P3), on to the ceramic Heating elements 21 and along them, further through the openings 28 and finally through the gas inlets 17, 18, 19 back into the furnace chamber 2 promotes. The furnace gas is heated as it slides past the ceramic heating elements 21, so that the correspondingly heated gas is then fed back into the furnace chamber 2 via the gas inlets 17, 18, 19, indicated by the arrows P1.

Dabei wird das erhitzte Gas über die unteren Gaseinlässe 17 in den Gasverteilraum 20 eingeleitet und über die darüber angeordneten Gaseinlässe 18, 19 in Richtung der jeweils äußeren Reihen von aufeinandergestapelten Brennhilfsmitteln 9, die den Seitenwänden 4, 5 jeweils benachbart sind, geleitet. Im Gasverteilraum 20 verteilt sich das eingeleitete Gas und strömt anschließend durch die zwischen den Brennhilfsmitteln 9 ausgebildeten Spalte 26 vertikal aufwärts (angedeutet durch die Pfeile P2) bis in den Bereich der Ofendecke 3, wo es den Ofenraum 2 wiederum über die Gasauslässe 10 verlässt. Das über die Gaseinlässe 18, 19 in den Ofenraum 2 eingeleitete Gas strömt zwischen den äußeren Stapeln der Brennhilfsmitteln 9 und den Seitenwänden 4, 5 vertikal aufwärts bis in den Bereich der Ofendecke 3, wo es den Ofenraum 2 ebenfalls über die Gasauslässe 10 verlässt. Entsprechend wird Gas kontinuierlich im Kreislauf umgewälzt.The heated gas is introduced via the lower gas inlets 17 into the gas distribution chamber 20 and via the gas inlets 18, 19 arranged above it in the direction of the respective outer rows of stacked kiln furniture 9, which are respectively adjacent to the side walls 4, 5. The introduced gas is distributed in the gas distribution space 20 and then flows through the gaps formed between the kiln furniture 9 26 vertically upwards (indicated by the arrows P2) to the area of the furnace roof 3, where it again leaves the furnace chamber 2 via the gas outlets 10. The gas introduced into the furnace chamber 2 via the gas inlets 18, 19 flows vertically upwards between the outer stacks of the kiln furniture 9 and the side walls 4, 5 to the area of the furnace roof 3, where it also leaves the furnace chamber 2 via the gas outlets 10. Accordingly, gas is continuously circulated in the circuit.

Dabei können die Brenngase im Ofenraum 2 im Wesentlichen vertikal aufwärts strömen. Eine Strömung der Brenngase in horizontaler und insbesondere auch in Transportrichtung kann praktisch vollständig vermieden werden.The combustion gases in the furnace space 2 can flow essentially vertically upwards. A flow of the combustible gases in the horizontal direction and, in particular, also in the transport direction can be practically completely avoided.

Von den im Kreislauf umgewälzten Brenngas können Teile als Abgas abgezogen. Hierzu kann über die Abgasleitungen 31 Brenngas aus dem Freiraum 13 abgezogen, durch Öffnung der Ventile 33 aus dem Ofen 1 ausgeleitet und einer Abgasbehandlung zugeführt werden. Ferner kann dem Brenngas Frischgas zugeführt werden. Hierzu kann durch Öffnung der Ventile 34 über die Frischgasleitungen 32 Frischgas, beispielsweise Luft oder Sauerstoff, im Bereich der Öffnungen 28 in den Kreislauf der Brenngase eingeleitet werden.Parts of the fuel gas circulated in the circuit can be drawn off as waste gas. For this purpose, fuel gas can be withdrawn from the free space 13 via the exhaust gas lines 31, discharged from the furnace 1 by opening the valves 33 and supplied to an exhaust gas treatment. Fresh gas can also be supplied to the fuel gas. For this purpose, fresh gas, for example air or oxygen, can be introduced into the circuit of the combustion gases in the area of the openings 28 by opening the valves 34 via the fresh gas lines 32 .

Der Tunnelofen 1 wird dabei mit einer oxidierenden Ofenatmosphäre betrieben, wobei die Sauerstoffkonzentration im Ofenraum 2 über 95 Volumen-% liegt.The tunnel kiln 1 is operated with an oxidizing kiln atmosphere, the oxygen concentration in the kiln chamber 2 being over 95% by volume.

Über die keramischen Heizelemente 21 wird der Ofenraum dabei derart beheizt, dass die Temperatur im Ofenraum 2 etwa 1.100 °C beträgt. Hierdurch kann das in den Brennhilfsmitteln 9 befindliche pulverförmige Kathodenmaterial synthetisiert werden.The furnace chamber is heated via the ceramic heating elements 21 in such a way that the temperature in the furnace chamber 2 is approximately 1,100°C. As a result, the powdery cathode material located in the kiln furniture 9 can be synthesized.

Aufgrund der vorbeschriebenen Strömungsverhältnisse im Ofenraum 2 kommt es dabei zu keiner Verwirbelung des pulverförmigen Kathodenmaterials.Due to the above-described flow conditions in the furnace chamber 2, there is no turbulence of the powdered cathode material.

BezugszeichenlisteReference List

11
Tunnelofentunnel kiln
22
Ofenraumoven room
33
Ofendeckeoven cover
44
Linke Seitenwand des OfenraumsLeft side wall of the furnace room
55
Rechte Seitenwand des OfenraumsRight side wall of the furnace room
66
Ofenwagenkiln car
77
RäderWheels
88th
Schienenrails
99
Brennhilfsmittelkiln furniture
1010
Gasauslassgas outlet
1111
Motorengine
1212
Gebläsefan
1313
Freiraumfree space
14, 1514, 15
Seitenverkleidung des StahlmantelsSide paneling of the steel jacket
1616
Deckenverkleidung des StahlmantelsSteel jacket ceiling cladding
17, 18, 1917, 18, 19
Gaseinlässegas inlets
2020
Gasverteilraumgas distribution room
2121
Keramische HeizelementeCeramic heating elements
2222
Oberseite der OfenwagenTop of the kiln cars
2323
Labyrinthverschlusslabyrinth closure
2424
Fundament der SeitenverkleidungenFoundation of the side panels
2525
Auflagenpads
2626
SpalteSplit
2727
Stahlmantelsteel jacket
27.1-427.1-4
Wandteile des StahlmantelsWall parts of the steel jacket
2828
Öffnungenopenings
2929
Einlaufschleuseinlet lock
3030
Auslaufschleuseoutlet lock
3131
Abgasleitungenexhaust pipes
3232
Frischgasleitungenfresh gas lines
3333
Ventile der Abgasleitungenexhaust pipe valves
3434
Ventile der FrischgasleitungenFresh gas line valves
P1-P3P1-P3
Gasströmungengas flows

Claims (13)

  1. Tunnel kiln for heat treatment of products, comprising the following features:
    1.1 A tunnel-like kiln chamber (2) which extends from a first end to a second end of the kiln chamber (2), the kiln chamber (2) being limited on the upper side by a kiln ceiling (3) and on the side by kiln walls (4, 5);
    1.2 kiln cars (6) which can be moved from the first end to the second end along a transport direction through the kiln chamber (2) and on which products to be treated with heat in the kiln chamber (2) can be transported;
    1.3 kiln furniture (9) for receiving the products, the kiln furniture (9) being arranged on the kiln cars (6);
    1.4 gas outlets (10), via which gas present in the kiln chamber (2) can be discharged from the kiln chamber (2);
    1.5 gas inlets (17, 18, 19) via which gas can be introduced into the kiln chamber (2); and
    1.6 means (21) for heating the kiln chamber (2); wherein
    1.7 gas located in the region of the kiln ceiling (3) can be discharged from the kiln chamber (3) via the gas outlets (10);
    1.8 gas in the region of the kiln walls (4, 5) can be introduced into the kiln chamber (4, 5) via the gas inlets (17, 18, 19); wherein
    1.9 the kiln furniture (9) being arranged on the kiln cars (6) with the formation of at least one vertical gap (26) between the kiln furniture (9); wherein
    1.10 the means (21) for heating the kiln chamber (2) are electric heating elements; wherein
    1.11 gas which can be introduced into the kiln chamber (2) via the gas inlets (17, 18, 19) can be heated by the heating elements before the gas is introduced into the kiln chamber (2); and wherein
    1.12 gas can be introduced into the kiln chamber (2) at different heights via the gas inlets (17, 18, 19).
  2. Tunnel kiln according to claim 1, in which gas can be introduced into the kiln chamber (2) below the kiln furniture (9) via the gas inlets (17, 18, 19).
  3. Tunnel kiln according to at least one of the preceding claims, in which the gas inlets (17, 18, 19) and the gas outlets (10) are arranged in such a way that gas can be guided through the kiln chamber (2) while forming an upwardly directed gas flow.
  4. Tunnel kiln according to at least one of the preceding claims, in which the gas inlets (17, 18, 19) and the gas outlets (10) are arranged in such a way that gas can be guided through the kiln chamber (2) while avoiding a horizontally directed gas flow.
  5. Tunnel kiln according to at least one of the preceding claims, in which the gas inlets (17, 18, 19) and the gas outlets (10) are arranged in such a way that gas can be guided through the kiln chamber (2) while avoiding a gas flow according to the counterflow principle.
  6. Tunnel kiln according to at least one of the preceding claims, in which the gas inlets (17, 18, 19) and the gas outlets (10) are arranged in such a way that gas can be guided through the kiln chamber (2) while avoiding a gas flow in the transport direction.
  7. Tunnel kiln according to at least one of the preceding claims, in which a gas distribution space (20) is formed below the kiln furniture (9).
  8. Tunnel kiln according to claim 7, in which gas can be introduced into the gas distribution space (20) via the gas inlets (17, 18, 19).
  9. Tunnel kiln according to at least one of the preceding claims, in which at least one of the at least one gaps (26) between the kiln furniture (9) runs in the transport direction.
  10. Tunnel kiln according to at least one of the preceding claims, with kiln furniture (9) in the form of stackable kiln furniture.
  11. Tunnel kiln according to at least one of the preceding claims, which is sealed in a gas-tight manner.
  12. Method of operating a tunnel kiln, comprising the following steps:
    12.1 providing a tunnel kiln (1) according to at least one of the preceding claims;
    12.2 moving the kiln cars (6) along the transport direction through the kiln chamber (2);
    12.3 discharging gas present in the kiln chamber (2) via the gas outlets (10);
    12.4 introducing gas into the kiln chamber (2) via the gas inlets (17, 18, 19); and
    12.5 heating the kiln chamber (2) via the means (21) for heating the kiln chamber (2).
  13. Use of a tunnel kiln according to at least one of claims 1 to 11 for heat treatment of products in the form of powder.
EP20199362.3A 2020-09-30 2020-09-30 Tunnel furnace for heat treatment of products, a method for operating such a tunnel furnace and the use of such a tunnel furnace Active EP3978854B1 (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
DK20199362.3T DK3978854T3 (en) 2020-09-30 2020-09-30 Tunnel furnace for heat treatment of products, a method of operating such a tunnel furnace and the use of such a tunnel furnace
SI202030123T SI3978854T1 (en) 2020-09-30 2020-09-30 Tunnel furnace for heat treatment of products, a method for operating such a tunnel furnace and the use of such a tunnel furnace
ES20199362T ES2929591T3 (en) 2020-09-30 2020-09-30 Tunnel kiln for heat treatment of products, method for operating such a tunnel kiln and use of such a tunnel kiln
PT201993623T PT3978854T (en) 2020-09-30 2020-09-30 Tunnel furnace for heat treatment of products, a method for operating such a tunnel furnace and the use of such a tunnel furnace
EP20199362.3A EP3978854B1 (en) 2020-09-30 2020-09-30 Tunnel furnace for heat treatment of products, a method for operating such a tunnel furnace and the use of such a tunnel furnace
HUE20199362A HUE060601T2 (en) 2020-09-30 2020-09-30 Tunnel furnace for heat treatment of products, a method for operating such a tunnel furnace and the use of such a tunnel furnace
PL20199362.3T PL3978854T3 (en) 2020-09-30 2020-09-30 Tunnel furnace for heat treatment of products, a method for operating such a tunnel furnace and the use of such a tunnel furnace

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP20199362.3A EP3978854B1 (en) 2020-09-30 2020-09-30 Tunnel furnace for heat treatment of products, a method for operating such a tunnel furnace and the use of such a tunnel furnace

Publications (2)

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EP3978854A1 EP3978854A1 (en) 2022-04-06
EP3978854B1 true EP3978854B1 (en) 2022-10-05

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EP (1) EP3978854B1 (en)
DK (1) DK3978854T3 (en)
ES (1) ES2929591T3 (en)
HU (1) HUE060601T2 (en)
PL (1) PL3978854T3 (en)
PT (1) PT3978854T (en)
SI (1) SI3978854T1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB886524A (en) * 1958-08-06 1962-01-10 Aton Planungs & Baugesellschaft Fuer Die Keramische Industrie Mbh Improvements relating to tunnel kilns
JP4400158B2 (en) * 2003-09-24 2010-01-20 旭硝子株式会社 Heating method for plate
WO2007111045A1 (en) * 2006-03-27 2007-10-04 Hirata Corporation Temperature treating unit and temperature treating system
WO2008063538A2 (en) * 2006-11-21 2008-05-29 Corning Incorporated Method and apparatus for thermally debinding a ceramic cellular green body
US20100127418A1 (en) * 2008-11-25 2010-05-27 Ronald Alan Davidson Methods For Continuous Firing Of Shaped Bodies And Roller Hearth Furnaces Therefor

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PL3978854T3 (en) 2023-01-02
DK3978854T3 (en) 2022-11-07
EP3978854A1 (en) 2022-04-06
SI3978854T1 (en) 2023-01-31
ES2929591T3 (en) 2022-11-30
PT3978854T (en) 2022-11-08
HUE060601T2 (en) 2023-03-28

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