DE1771377A1 - Enamelling tunnel furnace - Google Patents

Description

DR. MÜLLER-BORE dipl.-ing. GRALFS 1771377

DIPL.-PHYS. DR. MANITZ DIPL.-CHEM. DR. DEUFEL PATENTANWÄLTE

14. Hai '1968 Fi / Sv - l 2.7'

"Le Four industrial beige" Ι2-1Λ-, rue des Irois-Arbrea, TJccle, Belgium

Enamelling tunnel kiln

The jirl'induiig concerns an iümaillier tunnel furnace, and in particular a tunnel oven for enamelling bathtubs and similar objects.

So far, indirect heating has been used in the ülmaillier tunnel kiln by radiation from a muffle, tubes or electrical resistors. However, such a heater has numerous disadvantages. The amount of heat transferred by radiation decreases proportionally to the square the distance between the .two surfaces between which the Radiation occurs. .

The result is that for example in a buffalo, ä * Edie to burning objects or parts of objects to the brennen- _s, which are located near the wall of the muffle,

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BRAUNSCHWEIG. AM BÜRGiRPARK · "S C0B3I1 2 14» 7 · MUNICH 22.RQBIBiIJOCHSTrI, 1 'S lOeil) 22 BI IO

'. • are much hotter than the objects or parts in the KIi: tr: ά ·; Γ lr =: no. · "Chamber.

In addition, it follows from Stefan Öolzman's law that when any object is brought between the radiating surface and the object to be heated, this one Item no longer eufgshoizt v / iru in a suitable manner. This is the appearance of the drop shadow.

Another very serious drawback of heat transfer by radiation is that the thin TEII ¹ ^ of the articles overheating of the thick parts with respect Werdi-n.

The aim of the invention is essentially the aforementioned To eliminate disadvantages and to create a tunnel oven, which makes it possible to the objects to be heated a To obtain full isothermal energy, there is a considerable reduction in internal stresses during the rise in To achieve the temperature of these objects and a better transfer of heat to the enamel of the objects to be heated and to ensure better glazing of the enamel.

An enamelling tunnel furnace according to the invention has at least a carrier which is displaceable entirely within the combustion chamber of the furnace according to the longitudinal axis of this furnace and on which the to be heated Objects can be attached, the

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Br:; in the chamber is tightly sealed and thus the structure of a Allow overpressure in the chamber, as well as in the combustion chamber mlndonde burner, which is in at least one of the walls of this chamber are attached in such a way that a heating of the ! 'rager attached objects by convection by means of the coming from the burners and transversely to the longitudinal axis of the "" combustion chamber directed exhaust jets is possible.

According to an advantageous embodiment of the invention the carrier consists of a platform that slides on rails, which extend inside the combustion chamber according to the longitudinal axis of this chamber.

In a preferred embodiment, the furnace according to FIG Invention one in the bottom of the combustion chamber near the exit provided j'all door, which by a vertically movable lowering plate in the way that it can be closed is to guide the carrier that has arrived on the flattening out of the combustion chamber, v / obei a conveyor device below the combustion chamber is provided, which makes it possible to bring the carrier out of the combustion chamber back to the entrance of the combustion chamber at the exit of the combustion chamber (feifvorrichtungen provided, which enable the on, the carrier, which is on the plate, placed objects in front of ' the lowering of the plate through the exit.

109851/0364

Further details and advantages of the invention are provided in following based on a special embodiment of a Enamelling tunnel furnace according to the invention with reference explained on the drawing, for example.

In Zc ic mixing ζ · -. ■ i gt:

Fig. La, 1b, 1c partially broken Aufri.B-views an enamelling furnace according to the invention,

FIG. 2 shows a plan view of the arrangement according to FIG

Figure 3, a sectional view along the line III-III of Fig. 1c.

In the individual figures, the same elements are given the same reference symbols Mistake.

The tunnel shown in dsr_ individual figures ο fen for enamelling of bathtubs consists of a stable: ·: - Irügorkonctruktion ', vslche a combustion chamber 2 delimits, öi-j in α praise successive Areas 3 through 9 are divided, each of which may contain a bathtub 10 arranged on a support '.1, the temperature of these areas being regulated separately can.

The 'carrier 11 b-3 stand, ü from platforms that by means of sliding blocks 12 slide inside the jammers 2 on rails IJ, which

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extend eprecliend the longitudinal direction of the chamber. These platforms 11 v / earth formed by zvjei thrust tubes 14 and "i5, the

run parallel to the axis of the combustion chamber 2 / and are surrounded by very light material Y / with high insulating properties, whereby these materials Y / are clad with constant steel sheets Io, - -

The bath arms 10 are arranged on cradle-shaped frames 18, vjelche are attached to the platforms 11 and the Hold bathtubs 10 with a minimum of points of contact in the direction of the axis of the combustion chamber 2.

Burners 19 opening into the combustion chamber 2 are in the side wall 27 of the chamber in oiner between the platforms 11 and the bathtubs 10 located height-attached in such a way that it is possible to create a circulation of the combustion gases coming from the burners 19 around these bathtubs 10, so that in this way and equally conditioned by the form the chamber 2 a maximum heat transfer by convection between these gases and those in the cradle-shaped racks attached bathtubs 10 is achieved.

The burners 19 are in stoichiometric conditions and an additional small excess of air fed in such a way that in the combustion chamber 2 completely burned gases can be obtained. The burners 19

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emit gas jets at a speed of the order of magnitude - ^τ οη 100 ia per second, and due to the injector effect, these jets take the surrounding gases of the combustion chamber 2 with them in the direction of the file 40, εο that at this point ^ in the combustion chamber a whirl is generated according to the direction of the arrows 41 (see Figure 3) · This promotes the heat transfer by convection, since this is proportional to the speed of the sieve, with the objects to be heated in contact.

A trap door 21 is provided in the floor of the combustion chamber 2 in the area 9 of this chamber. This trap door 21 is closed by a vertically movable lowering plate 23 in such a way that it is at the point of the burning process that the platform 11, which has been pushed onto the piaute 2 ^, is to be brought out of the chamber 2 and at the level of a conveyor ^{To bring z} > -2, which is arranged in a pit 22 below the combustion chamber 2. Ji ο fire device 42 ensures the return of the empty platforms 11 carried out from the combustion chamber 2 and the trap door 21 to the entrance of the chamber 2. At the exit 24 of the combustion chamber 2 gripping devices formed by an automatic unloading device are provided, which are not shown in the figures . By means of these gripping devices, the fired bathtubs 10 can be led out via the exit 24 at the point in time at which the platform 11 passes over the trap door 21 and before the lowering of the plate 23 takes place.

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■ η

The Abs e21lr.pl at te 23 is mounted on scissor-shaped stands 2C, the mutual. Distance of this stand is controlled by hydraulic jacks 28 in the v / else, dai: it is possible, the plate 23 between the door 21 and the case I'ördervorri - :; Pla, ^for raising and lowering -2, üie conveying device has two Snail chains 43 and 4, which each run on both sides of the plate 25 in a lowered position in vertical planes between the plate 23 and the entrance 25 of the combustion chamber 2. A transverse push rod 45 is attached between the two chains 43 and '■; - ■ * and ensures, by acting on the rear hand of the platform 11 located on the lowered plate 23, a displacement of this platform from the plate 23 on rails 46, the extend between the chains 4J and 4 · + to the entrance of the combustion chamber 2.

The plate 23 also has rails --V /, which in the raised Position of the, plate in the extension of the rails 70 are attached, which run inside the combustion chamber 2, and in the lowered position of the plate 25, the extension of the rails 46 of the conveyor device 42 .represent.

A lifting plate 48 is provided at the inlet 25 of the combustion chamber 2. This lifting plate 48 allows one from the combustion chamber 2 led out and returned by the conveyor 42 under the entrance 25 of the chamber 11 to the height of this entrance 25 in the way

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raise that this with a new bath 10 boladcne platform 11 again inserted into the area 3 of the combustion chamber 2 can be, üiose lifting plate -4-0 is of the same type as the Lowering plate 23 and is also controlled by hydraulic winches 28 which are mounted on scissor-shaped crossed stands 20 below the plate -18 act in such a way, dal ', serve between the conveying device 4-2 and the inlet 25 of the combustion chamber 2 can be raised and lowered.

The lifting plate 4-8 is controlled by a drive device 4-9, by means of which this plate 4-8 a reciprocating movement corresponding to the direction of movement of the chains 4-3 and 44 between a position remote from the conveyor device 4-2 and a position closer to it gives four the can. The movements of the lifting plate 4-8 and the conveying device 4-2 are synchronized in such a way that the empty platform 11 can be brought onto the rails 50 of the lifting plate 48 on the one hand by the rails 4-6 of the conveying device 42 onto the rails 50 of the lifting plate 48, namely at the time at which it assumes the lowered position shown in broken lines in Fig. 1 and is in the position near the conveyor 4-2, and on the other hand, the push rod 4-5 between the ends of the rails 4-6 of the conveyor 4-2 and the plate 4-8 can arrive at the point in time at which it is in the position remote from the conveyor device 4-2.

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The lifting plate 48 is in the position near the conveyor 42, the rails 50 are arranged in the extension of the "rails 46".

The already mentioned drive device 49 comprises a tleuelstangen-crank system 54 which is articulated to a chassis 51 which supports the uprights 20 and the plate 48. The chassis 51 is provided with Eollen 52 on rails 55 i- ^{such a} way that the chassis a reciprocating movement may be given due to the action of the connecting rod-crank system 54 ⁿ run.

One. Lowering device 55 is provided opposite the entrance of the combustion chamber 2.

The thrust device 55 is guided on both sides of the lifting plate 48 on rails 56 which are parallel to the longitudinal axis of the combustion chamber 2. A slide 57, which is driven by a connecting rod crank system 58, can move on these / rails 56 a little above the lifting plate 48, which is in the raised position, and one on the plate 48. orderly platform 11 push into the combustion chamber 2.

• The connecting rod system 58 acts on a shaft 59 that

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each of its ends has a pinion 60, which on the one hand with its lower part with a fixed rack mounted on the rails 56 parallel to the axis of the combustion chamber 2 and on the other hand with its upper part meshes with a rack 61 which is attached to the carriage 57, namely in the Way that the translational speed of the carriage 57 is twice as great as the translational speed of the pinion is.

The exit door 31 is by means of an eccentric 35 in the way controlled that a quick closing and opening of the door is possible and thus the ingress of air is reduced to a minimum value.

At the entrance 25 of the combustion chamber 2, a door 64 is also provided, which can open at the time at which the Lifting plate 48 assumes the position removed from the conveyor 42. This door 44 opens from top to bottom, as well as incidentally the exit door 31 »around between the plate 23 and the conveyor 42 intervene.

Due to the fact that the combustion chamber 2 of the furnace according to the invention in a perpendicular to the longitudinal axis there? Chamber 2

Section tight

running ifr completely / is, it is possible to achieve a very strong heating in this chamber by convection by means of a flow of exhaust gases, which is essentially transverse

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flow to the longitudinal axis of the chamber 2. Due to the fact that the speed of these gases generates kinetic pressures on the walls of the combustion chamber, this tightness is indeed essential necessary.

Another problem solved by the furnace according to the invention is, is to avoid that at the exit 24 of the combustion chamber 2 a very hot bathtub 10 and a very hot one Carrier 11 can be obtained, which is very difficult to achieve due to its dimensions, weight and high temperature handling carrier 11 must be returned to the entrance of the combustion chamber 2 again. For this purpose use the bathtub 10 and the support 11 separated from the combustion chamber 2 by two various exits led out.

A first ICamin 29 for the removal of the exhaust gases, the opposite to the direction of advance of the bathtubs 10, is in connection with the area 3 of the combustion chamber 2, which in Located near entrance 23, while a second fireplace

30 is provided in the intermediate carriers of the outlet 24 of the chamber 2 is. This second chimney 30 is only during opening the trap door 21 and the one provided at the exit 24 of the combustion chamber 2 Door 32 open, with the first chimney 29 in this Trap is closed. That way the through the door '

31 and air entering through the trap door 21 through the chimney discharged while the gases coming from the burners 19, the

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cannot escape through the chimney 29, prevent the air from penetrating into areas 3 to 8 of the combustion chamber. These gases are then discharged with the air through the chimney JO. The presence of the chimney 30 makes it possible to maintain a fixed mixture in the combustion chamber which contains between 0.5 and 1.5 % oxygen.

Areas 3 and 4 of the combustion chamber 2, which are close to the chimney 29 are not equipped with burners 19 in the present case and form areas for heat recovery. the Combustion gases from the other areas 5 to 9 circulate here in the opposite direction to the direction of movement of the bathtubs 10 and exit through the chimney 29.

In order to have a transverse circulation of the in areas 3 and 4 Generating exhaust gases, i.e. subjecting the exhaust gases to a vortex movement along the axis of the combustion chamber 2, are in the wall 27 of the combustion chamber 2 inspector ramps 33 are provided.

These injectors or injection nozzles 33 are operated by an engine fan 34 fed, which via pipes 63 a 'part of the exhaust gases the combustion chamber 2 is sucked in and these gases are brought to the desired pressure so that they are at the output of the ingectors 33 a Have sufficient kinetic energy to ensure the creation of transverse circulation in areas 3 and 4. This circulation is in the other areas 5 to

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automatically created by the burner 19 itself.

It is also possible to use injectors from 5 "to 9 33 to be provided in such a way that when the burner 19 slows down are working or at a standstill, the required circulation of the exhaust gases is guaranteed. This latter jail can occur, for example, if the heating program of the bathtubs 10 does not require any heat supply in a certain zone.

The tunnel oven described above, in which the bathtubs 10 by spraying or. Dipping enamel compound is burned, works as follows: -

In BOrmal operation, the combustion chamber has swei 2 in each of the areas 3 to 9 have a platform 11 which carries a bathtub 10 in cradle-shaped frames 18. The thrust tubes 14 and 15 of the platforms 11 are butted against each other in such a way that it is possible to move the platforms from one area to one to push others by pushing on the platform 11 located in the first area. If a bathtub 10 arrives in area 9 above trap door 21, it is burning this bathtub ended, the door 31 opens and the bathtub 10 is through the exit 24 by means of an automatic Unloading device executed * Gate that the door 24 is open the chimney 29 is closed and the chimney 30 is open.

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then the plate 23 is lowered and thus leads the empty platform 11 out of the combustion chamber 2. When the plate 23 arrives at its lowered position, as shown in dashed lines in As shown in Fig. 1c, the rails 47 of the plate pass into the Extension of the rails 46, and the platform 11 is pushed onto these rails 46 by the rod 45.

The plate 23 closes the trap door 21 again in such a way that the pusher 55 pushes the bathtubs 10 into the combustion chamber can move one step further, i.e. each of the bathtubs can be pushed into a subsequent area, that it is possible to introduce a platform 11 with a new bathtub in the first area 3.

After the lifting plate has been unloaded in this way, it is lowered into its and after closing the entrance door 25 placed in the vicinity of the conveyor 42 position.

The rod 45 then strikes the empty platform 11 Lifting plate 48, which it lifts up to the entrance 25 of the combustion chamber 2.

At this time, a new bathtub 10 can be brought into the cradle-shaped frames 18 of the platform, which rests on the lifting plate 48 in such a way that a new cycle can begin. _{1098B1 / 0364}

Limit switches, not shown, guarantee safety of the various processes. . .

- patent claims -

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Claims (12)

■ ..- - 16 - claims 1. jümaillier tower furnace, especially tunnel furnace for enamelling of bathtubs, marked by at least one support that is completely within the combustion chamber of the Oven is displaceable according to the longitudinal axis of this oven and attached to the objects to be heated can be, wherein the combustion chamber is tightly closed and allows the generation of an overpressure, as well as by Burners which open into the combustion chamber and are mounted in at least one of the walls of the combustion chamber in such a way that heating by convection of the objects placed on the carrier by means of the objects coming from the burners and exhaust gas jets directed transversely to the longitudinal axis of the combustion chamber is possible. 2. Furnace according to claim 1, characterized in that that the carrier consists of a platform that slides on rails which are inside the combustion chamber according to the The length of this chamber runs. 3. Furnace according to claim 1 or 2, characterized in that a trap door is provided in the bottom of the combustion chamber near the exit of this chamber, .that this trap door can be closed by means of a vertically retractable plate in the V / iron that the on the Plate arriving support from which it can be guided out, <lc-. ~. 'Hit rhslb the burning 109851/0384 chamber a conveying device is provided, which a Bückführung the led out of the combustion chamber carrier allows to the entrance of the combustion chamber, and that gripping devices are available at the exit of the combustion chamber, by means of which through this exit is the one on the "disk" Supported objects can be taken out before lowering this plate. 4. Oven according to claim 3, characterized ge k e η η ζ e i c h η et, that a lifting device is provided at the entrance of the combustion chamber is, which enables the led out of the combustion chamber and by means of the conveyor device returned to the entrance of the combustion chamber empty carrier to the level of the To be raised at the beginning in such a way that this carrier can be reinserted into the combustion chamber after being loaded with objects to be heated. 5. Oven according to claim 3 or 4, characterized in that it is marked e t that the conveyor has two endless chains or belts, which are in vertical planes on either side of the Plate in the lowered position between this plate and the entrance of the combustion chamber run that between the two Chains or straps attached to a rod that is in the It can be pushed over the plate in the lowered position so that it is possible to sit on this plate to move the carrier located to the entrance of the combustion chamber. '109851/0364 6. Oven according to claim 4 or 5> characterized in that a device for driving the lifting device is provided which allows this to reciprocate between one remote from the conveyor Position and a position approximated to this conveyor device that the movements of the lifting device and the conveying device are synchronized in such a way that on the one hand the conveying device has a carrier to the The point in time can be transferred to the lifting device at which it has approached the carrier and assumes the lowering position, and on the other hand, the passage of the organs of the conveyor device at the moment when the lifting device is enabled is removed from the conveyor. 7. Oven according to one or more of claims 4 to 6, characterized gekennz eichnet that opposite the entrance of the combustion chamber a thrust device is provided and that this Device can act on a carrier arranged on the lifting device in the raised position in such a way that this is introduced into the combustion chamber. 8. Oven according to claim 7 »characterized in that the two sides of the lifting device on to the longitudinal axis the combustion chamber parallel rails guided thrust device has a slide, which is driven by a connecting rod system is driven that this slide on this slide 109851/0364 ^ß AD ORIGINAL NEN is displaceable over the lifting device and by means of push rods in the manner on the lifting device mounted in the raised position carrier can act that this is inserted into the combustion chamber. 9 · Gfen according to claim 8, characterized in that ge k e nn ζ ei ch η e t, that the Eurobar system acts on a shaft which, at each of its ends has a tickle that this pinion on the one hand with its lower part with a fixed rack, which is mounted on the guide rails parallel to the axis of the combustion chamber, and on the other hand with its upper Part meshes with a rack, which is mounted on the carriage moving on the guide rails, and in such a way that the translational speed of the sled is twice as large as that of the Eitzel. 10. Oven according to one or more of the preceding claims, gekennz ei chnet that the carrier at least has a cradle-shaped frame which is used to support the objects to be heated with a minimum of contact points serves and essentially in the axial direction of the combustion chamber so that the combustion gases along the surfaces the objects to be heated can flow. 11. Cfen according to one or more of the preceding claims, thereby g e k e η η ζ e i c h η e t that to discharge the 109 85 17 03 6 / » Combustion gases a with the one near the entrance of the Combustion chamber located combustion chamber area connected first chimney and for the discharge of the opening of the exit of the combustion chamber entering air is provided certain second chimney, which with the in the Near the exit_s of the combustion chamber chamber area is connected that the second chimney is simultaneously with the exit of the combustion chamber can be closed and opened, that the first chimney is closed when the second Fireplace is open and that the first fireplace eats open when the second fireplace is closed. 12. Oven according to one or more of the preceding claims, characterized in that the combustion chamber has a heat recovery area in the vicinity of its entrance. aufv ^T eiST; and Ίβι .. this area is not equipped with burners \ .τΛ from the combustion gases coming from other areas in the opposite direction to the movement of the carrier by-.. . . "
Direction g *> c ~ rornt; we α. IJ. Oven according to one or more of the preceding claims, characterized in that at least one injector in one of the walls of the combustion chamber is at least mounted in de _m located in the vicinity of the entrance of the chamber area, and that this injector by a fan 109851 / 036A is fed, which absorbs gases in the combustion chamber and a gas flow transverse to the longitudinal axis of this chamber generated. . . Furnace according to one or more of the preceding claims, characterized in that the burners open into the combustion chamber at a height which lies between the carrier and the object or objects arranged on it, so that the object or around the objects a circulation of the combustion gases is established. 109861/0364 bad omg.nal Le e rs e ι te