DE2001148A1 - Tunnel furnace - Google Patents

Description

DR. ING. E. HOFFMANN · DIPL. ING. W. EITLE DR. RER. NAT. K. HOFFMANN P ATK NTANWORTE D-8000 MÖNCHEN 80 · MARIA-THERESIA-STRASSE 6 · TELEPHONE (0811) 4410 61 2001 I.

S.C.E.I. Societa Costruzioni Elettrotermiche Industriali

in Novara / Italy

Tunnel furnace

The present invention relates to a tunnel furnace with one or more firing channels for firing of ceramic or clay ware, with all the organs for heating and controlling the tunnel kiln in the area of the Ceiling wall are arranged so that separate operation for the individual combustion channels is possible.

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It is known that all clay-containing materials used extensively in the ceramic and building industries have one or more sensitive temperatures during preheating, during which a strong heat absorption occurs, whereby the material to be burned is not treated directly with gases that are too hot or not in may come into direct contact with the lambs. At these sensitive temperatures, for example, the in Water bound in the clay is eliminated or, in the case of some materials, this bound water is eliminated before it is eliminated Water gasifies or carbonizes organic substances.

In the previously known tunnel kiln, the material to be burned is on a train of wagons or on one Conveyor belt guided along one or more parallel combustion channels. The material to be burned forms a flat layer consisting of individual pieces or of a few smaller sized pieces stacked on top of each other can, whereby the height of the item to be fired is generally not greater than 25-30 cm, but in some cases also can be above. However, the previously known tunnel kilns have the disadvantage that the heating of the material to be fired does not take place optimally, so that a certain waste of the material to be fired has to be accepted.

The aim of the present invention is to create a tunnel furnace which has this disadvantage of known tunnel furnaces does not have and which enables very even heating of the material to be fired, with damage to the Items to be fired are avoided as far as possible.

According to the invention, this is achieved by combining the following features:

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a) Burners are provided within the firing zone, the flames of which are not aimed directly at the material to be fired;

b) inside the preheating zone arranged outside of the tunnel furnace combustion chambers are provided which correspond to the volume corresponding to the temperature and the desired pressure within the various areas of the preheating zone Generate gases.

An advantageous embodiment of the invention is characterized in that the burners within each Combustion channel are arranged in longitudinal niches and that the burners are arranged such that the burners Flames generated at a certain distance from the material to be fired parallel in the direction of movement of the The material to be fired is directed.

It proves to be useful if the burners are arranged at one end of the longitudinal niches and that bevels are provided at the opposite ends of the longitudinal niches, under which each of the free spaces come to lie within the material to be fired

Another advantageous embodiment of the invention is characterized in that the combustion chambers are connected to fans, which optionally deliver cold air, warm recovery air or recirculated Suck in fuel gases, whereby the gases generated are brought to the desired pressure and temperature, and if so the combustion chambers are connected to at least one intermediate space arranged in the ceiling of the tunnel furnace, which in turn is connected to the combustion channel through the top wall via corresponding openings,

009835/1339

2001U8

In the tunnel furnace according to the invention, all of the heating elements and the regulating elements are arranged so that several combustion channels can be arranged side by side, regardless of the The number of combustion channels arranged next to one another results in a satisfactory functioning and an independent possibility of regulation.

Further details of the invention are explained in more detail below with the aid of an exemplary embodiment and referring to the accompanying drawings. Show it:

Fig. 1 is a schematic longitudinal sectional view of an embodiment of the tunnel furnace according to the invention} and

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG Fig. 1.

In the following, reference should be made to the figures, in particular FIG. 1, from which it can be seen that the tunnel furnace according to the invention has side walls 1, on which the top walls 2 of the individual combustion ducts rest. The individual combustion channels are arranged downwards through a series of one behind the other Completed car 3, which are moved in batches with the fuel 4 loaded on it, with the through the Carriage 2 conditional gaps 5 of the material to be fired 4 always come to lie at certain points of the tunnel kiln.

According to

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Fig. 2 on the carriage 3 spacer ^ 6 provided. Below of the material to be fired 4 free spaces are therefore formed 7, in which the gases used for heating can penetrate evenly, so that the burning The material to be fired is heated evenly from all sides.

A cover 8 is provided above each top wall 2 of each combustion channel, whereby one or form a plurality of intermediate spaces 9a-9d which are arranged one behind the other in the longitudinal direction. Based on Fig. 1 results that in the heating area of the tunnel furnace three spaces 9a-9c are provided in the cooling area and one space 9d are. The interspaces 9a-9d are connected to the combustion channel by means of a plurality of within the ceiling wall 2 arranged openings 10a - 1Od connected. The position of these openings 10a-d corresponds to the spaces 5 between the individual wagons or the items to be fired. In the area of the openings 10a-d there are controllable valve devices 11 is provided, by means of which the amount of gas flowing through the openings 10a-d can be influenced.

As can be seen from FIG. 1, each combustion channel is in the combustion zones within the ceiling wall 2 longitudinal niches 13 arranged, in which burner 14 protrude in such a way that the material to be fired 4 without damage high temperatures can be brought. The flames of the burners 14- are due to their angular design not directed directly against the material to be fired 4, but parallel to the direction of movement of the material to be fired 4, wherein there is a certain distance between the flames and the material to be fired 4. Each longitudinal niche 13 has the opposite The end of the burner 14 has a bevel 15, each above a free space 5 of the

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The material to be fired 4 comes to rest so that the hot gases are pressed directly through these spaces 4. on in this way, the hot gases are mixed with the gases coming from the previous zones of the tunnel kiln are mixed, also applied to the firing material 4 from the side and from below. The bevels 16 within the longitudinal niches 13 support the uniform Distribution of the combustion gases up to the item to be fired 4.

Above the combustion and cooling zone of the individual combustion channels there is a collecting space 9d, the is in Verbitiung via openings 1Od with the combustion channel. Through these openings 1Od the hot air is from a Cooling fan 17 sucked in and discharged via a pipe.

A strong supply of heat is necessary within the preheating zone of each firing channel without affecting what is to be burned Material, which is extremely sensitive at this point in time, can be exposed to gases that are too hot or in direct contact Contact with the flames of the burner may be brought. In the individual spaces 5 between the items to be fired 4 hot gases generated outside the tunnel furnace are consequently introduced, corresponding to the relevant Preheating point have been brought to the desired volume, temperature and pressure conditions. the hot gases are generated in one or more combustion chambers 19 »20, these combustion chambers 19» 20 with recovered Warm air can be fed. For example, the combustion chamber 20 is fed with hot air as shown, which comes from the space 9d. The heating gases for the combustion chamber 19 are, however, according to the illustration generated by exhaust gases that originate from the space 9a, which is still with a suction fan 25 and a pipe 24 is connected.

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The hot gases originating from the intermediate space 9a are fed with the aid of a fan 26 to the combustion chamber 19, in which these gases are mixed with the combustion gases from burners 22. The gas mixture thus formed is then fed to the intermediate space 9b ″, from which the gas flows through the openings 10d present within the ceiling wall 2 into the intermediate spaces 5 of the fuel 4 the combustion chamber 20 supplied to and mixed within the same generated by burner 21 with gas. the gas mixture formed is then the space 9c and from there through the openings 10c in the intermediate m

spaces 5 out between the kiln k . Blowers 26 and are used to give the combustion gases or hot air the necessary pressure, while the burners 21, 22, which are preferably provided with an automatic control device, are used to set the desired temperature.

The tunnel kiln according to the invention can be combined in a very simple manner with a device for preheating or drying kiln items, such devices being able to be arranged in the longitudinal axis of the drying kiln or to the side. In this case, the gases can be used directly for preheating or drying. The temperature setting can be %

take place by mixing with fresh air or hot gases, the latter can be withdrawn from the combustion chambers 19t 20.

It should be noted that certain modifications of the invention are possible. For example, there is the option of providing gas curtains made of air or hot gases, or of recirculating the gases. Further rapid cooling can be carried out if this is desired.

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Claims (8)

2001H8 _ 8 _ Claims 1. Tunnel furnace with one or more firing channels for firing ceramic or clay material, with all organs for heating and Control of the tunnel furnace are arranged in the area of the ceiling wall, so that a separate operation for the individual firing channels possible, characterized by the combination of the following features: a) Burners (14) are provided within the combustion zone, the flames of which are not directed directly at the item to be burned (4) b) inside the preheating zone are arranged outside of the tunnel kiln Combustion chambers (19 * 20) are provided, which correspond to the volume of the temperature and the desired pressure within the various Generate appropriate gases in areas of the preheating zone. 2. Tunnel furnace according to claim 1, characterized in that that the burners (14) are arranged in longitudinal niches within each combustion channel and that the burners (14) are arranged in such a way are that the flames generated by the burners (14) at a certain distance from the material to be fired (4) parallel in the direction of movement direction of the material to be fired (4). 3 · tunnel furnace according to claim 1 or 2, characterized in that g e k e η η, that the burners (14) are arranged at one end of the longitudinal niches (13) and that at the opposite ends of the longitudinal niches (13) bevels (15) are provided, under which the free spaces (5) within the material to be fired " (4) come to rest. 4. tunnel furnace according to claim 1, characterized in that that the combustion chambers (19, 20) with fans (26, 27) in -9-009835 / 1339 There is a choice of cold air and warm recovery air or sucking in returned fuel gases, whereby the gases generated are brought to the desired pressure and temperature and that the combustion chambers (Ϊ9, 20) with at least one in the ceiling of the Intermediate space (9a-d) arranged in the tunnel oven, which in turn is connected by the ceiling wall (2). through corresponding Openings (.1Oa - d) is in communication with the combustion channel. 5. Tunnel furnace according to claim J5 or 4, characterized in that the openings (10a - d) at intervals accordingly the spaces (5) of the material to be fired (4) are arranged and that an introduction of hot gases through these openings (lOa - d) he follows. 6. Tunnel furnace according to claim 4 or 5 *, characterized in that the openings (10a - d) with controllable valves facilities are provided. 7. tunnel furnace according to claim 1, characterized in that g e k en η ze i c hn e t that in the inner zone and the cooling zone of the tunnel furnace openings (10a, d) are arranged in accordance with the spaces (5) of the material to be fired (4) within the top wall (2) which the combustion channel is connected to an intermediate space (9a, d) arranged in the ceiling of the tunnel kiln. 8. tunnel furnace according to one of the preceding claims * thereby g e k e η η ζ e ic h net that the extracted gases directly one Drying device are fed in the axial extension of the tunnel oven or is arranged in parallel next to it. 009835/1339 Blank page