EP0012442A1 - Transport installation for furnaces for drying and/or firing - Google Patents

Abstract

1. A transport installation for furnaces for drying and/or firing, comprising at least one peripherally extending track link conveyor belt (3, 4) including singular separate supporting protrusions (35') distributed across the useful area of said transport installation with said supporting protrusions defining an arrangement in which gaps or spaces extending in the direction of conveyance are formed between said supporting protrusions, into which spaces the tines (23) of a transfer device may engage, characterized in that in the region of longitudinally disposed belt sections, said supporting protrusions (35') positioned between two spaces each have different levels of support, such that the surface line of the supporting points follows a concave contour line within a belt section.

Description

The invention relates to a device for drying and firing enamelled goods with an enamel application, with at least one drying oven and a continuous enamelling oven, as well as with transport devices running through the ovens and between the ovens.

Enamelling plants, which are designed according to modern aspects regarding the rationalization of the quality of work and the throughput speed, have drying and continuous enamelling ovens, which serve to dry the enameling goods, which are first provided with a basic order, then with an enamel order, and then burn at elevated temperature. From an article in the magazine Glas-Email-Keramo-Technik, 1963, page 391 ff., It is known to connect the furnaces mentioned at the beginning by means of a transport route which enables continuous operation. The conveyor system must be designed so that it can be adapted to the most favorable operating sequence. Here, circular conveyors with an articulated chain are generally used. It is important to ensure that a completely jerk-free run is achieved so that movement of the wet enamel layer is prevented.

It has been shown that transporting hanging parts has certain disadvantages. In particular are the ovens are open at the top, with problems regarding the guidance of the overhead conveyor and the attached baskets with the products, as well as heat losses, since the sealing at the top can never be perfect.

It is also known from the prior art mentioned to transport larger, flat parts by flat transport. Here wire ropes are used, on which the parts are placed. However, the enamel should not dry on the wire ropes if possible. Transport ropes and parts placed on them must therefore be separated again between the spray booth and the dryer.

It is therefore the task of creating a device for drying and firing enamelled goods, in which in particular the transport device or the transport devices through the furnace interior are designed in principle as a conveyor belt. The conveyor belt should be able to take up both small and large enamelware alternately without or with little changeover measures, without the enamel being practically considerably damaged during drying or firing.

The heat loss from the ovens must be kept as low as possible; nevertheless, an even drying and heating of the enamel layer of the goods must be guaranteed. The technical effort should be kept as low as possible. The ovens should also offer the opportunity to work with balanced temperature distributions. It should also be possible to coordinate the working speed of drying and kilns in a simple manner. Furthermore, it should be possible to spatially associate the drying oven and the enamelling oven in such a way that an economical and low-loss use of the heat content of the fuel gases heated in the enamelling oven is possible in the drying oven.

The object according to the invention is achieved in a device for drying and firing enamelled goods of the type mentioned in the introduction, in which the transport device consists of a conveyor belt which has singular support surfaces distributed over the usable area of the belt, the support surfaces taking up an arrangement in which Alleys are formed between the contact surfaces, in which the tines of a stacker member can engage. The conveyor belts that are passed through the ovens can have different widths. In general, the conveyor belts are formed in sections from interconnected webs which are aligned parallel to one another in the conveying direction and which have distributed on their upper side extremities, such as pins, prongs and the like, provided with contact surfaces.

The emailware is placed on the surfaces distributed in the manner described, contact being only between the conveyor belt and the emailware at very specific, distributed locations. Appropriate forklift bodies equipped with tines can then be used to intervene in the alleys or the spaces between the webs and to lift the enamelware. With the help of an intermediate belt, a movement of the stacker element or the like, the enamelled goods can then be placed from the dryer belt onto the belt which is assigned to the enamelling furnace. Several drying ovens can also be assigned to one enamelling oven or vice versa.

In order to adapt the conveyor belt with its distributed bearing surfaces to as many occurring sizes and contours of enamelware as possible, it is proposed that: in the conveying direction, bearing surfaces of a belt section lying one behind the other span a concave contour.

This ensures that wider enamelled goods only lie on two support surfaces lying one behind the other, which would not be possible with several support surfaces of the same height.

In addition, it is also possible to detachably connect the pins, prongs, etc. to the conveyor belt or the webs. In this way it is possible to easily adapt the conveyor belt to different part sizes, floor areas or contours.

Furthermore, it is proposed that a conveyor belt runs through each of the two types of furnace, and that a connecting belt is provided between the furnaces, with the connecting belt being assigned a transfer device at each furnace outlet or inlet, which has a height-adjustable stacker element with tines.

• Figur 1 eine Einrichtung zum Trocknen und Brennen von Emaillierware mit einem Trocknerofen und einem Durchlauf-Emaillierofen;
• Figur 2 a zeigt einen Schnitt gemäß II ... II der Figur 1;
• Figur 2 b eine Seitenansicht auf einen gemäß Schnitt III ... III seitlich geöffneten Ofen der Figur 2 a;
• Figur 3 a/b Details des Förderbandes mit einem Staplerorgan;
• Figur 4 die Umsetzstation von Ofenband auf Zwischentransportband in einer Ausführungsform;
• Figur 5 a/b Details einer bestimmten Ausführungsform der die singulären Auflageflächen tragenden Förderbandelemente;
• Figur 6, 6 a bis 6 d weitere Ausführungsformen der Förderbandelemente.

Embodiments of the invention are described below with reference to the accompanying drawings. The figures in the drawing show:

• 1 shows a device for drying and firing enamelled goods with a drying oven and a continuous enamelling oven;
• Figure 2 a shows a section along II ... II of Figure 1;
• 2b shows a side view of an oven of FIG. 2a open laterally according to section III ... III;
• Figure 3 a / b details of the conveyor belt with a stacker;
• Figure 4 shows the transfer station from oven belt to intermediate conveyor belt in one embodiment;
• FIG. 5 a / b details of a specific embodiment of the conveyor belt elements carrying the singular support surfaces;
• 6, 6 a to 6 d further embodiments of the Conveyor belt elements.

FIG. 1 shows the connected arrangement of a drying oven 1 with a continuous enamelling oven 2, seen from above, a conveyor belt 3 or 4 running through both parts, which is connected by a connecting belt 5. The working or transport direction is indicated by arrows.

After a basic order has been applied to the enamelled goods, the parts are pickled. The actual enamel is then applied by dipping or spraying. The parts provided with this initially moist coating arrive at the inlet 6 of the drying oven 1. They are dried in the drying oven at a temperature of approx. 100 ° C. Without further rework, the goods are lifted onto the intermediate belt and transferred to the conveyor belt 4 of the enamelling furnace. Here it is fired at a temperature of up to 820 ° C. After the actual firing process, the enamel layer is still relatively brittle. The goods arrive at exit 7 of the enamelling furnace and are then checked on a control route. A top coat can then be applied in additional spray booths. After passing through the latter booths, drying and possibly another firing process takes place. Since these processes do not always take place or, in principle, take place in the parts already described, further furnace details are not described separately.

It can be seen from FIG. 1 that the drying oven and the enamelling oven are arranged very close to one another, since the transport devices require little space and no deflection sections, and the working speed of the ovens can be matched very precisely to one another. It is therefore advantageous to keep short between the ovens To provide connecting channels 8, in which the hot fuel gases are passed into the drying oven, so that the energy stored in it can be further used (energy recuperation). The combustion gases occur at a temperature around 200 ° C higher than in the relevant segment of the combustion chamber when closed heating pipes are used (see FIG. 2 b).

Corresponding exhausters 9 ensure the transport of the gases. However, the hot gases must be of high purity, especially soot-free, since even the smallest dirt particles can render the goods worthless.

Figure 2a shows a section according to II ... II of Figure 1 in somewhat compared to this enlarged view. The enamelling furnace 2 is a tunnel furnace consisting of several sections in a basic construction known per se. The walls of the furnace consist of cladding and insulating compound. In the actual combustion chamber 10, the conveyor belt 4 runs on supports 11, which consists of numerous links extending across the width of the combustion chamber 10, which are equipped with individual webs on which pins, prongs and similar extremities are arranged, which are the enamelled goods 12 from support down.

Closed flame tubes 13 are installed on both sides of the combustion chamber 10. A burner 15, with which the hot fuel gases are generated, is provided at the head of each false tube 13. A fan arrangement 14 circulates the gases in the furnace atmosphere while uniformly flushing the combustion material and the flame tubes. Figure 2 b shows the configuration of the flame tubes when viewed from the side. Drain holes are also made in the upper part of the furnace housing, by means of which the drying or fuel gas can be fed to further sections of the tunnel furnace in the counterflow principle.

It is essential that the conveyor belt is permeable from below and the enamelled goods only have small contact surfaces, these being distributed over the usable area of the belt in the conveying direction in such a way that alleys are formed between the contact surfaces, in which the tines of a stacker member can engage. A possible implementation of this basic idea of the invention is shown in FIGS. 3a / b.

At the head of the conveyor belt coming from the furnace 1 there is a drive drum 16, which is driven, for example, by an electric motor (not shown). The drive drum 16 of the conveyor belt 3 has numerous recesses on its periphery, into which the connecting rods of the individual links 17, 18 engage. The individual links also consist of a base 19, on which numerous webs 20 are fastened, which in turn have carrying mandrels 21 on their upper side, which have a contact surface formed as a tip on their upper side. Enamelware 12 is placed on the mandrels 21; cooking pots are shown as examples. The webs are arranged at equal intervals across the entire width of the conveyor belt.

Tines 23 of a stacker member 24, not shown in all details, reach between the webs. Below the upper run of the conveyor belt 3 is the support surface or the upper run of the connecting belt 5, which is also equipped with individual webs 25, as is also provided by the conveyor belt 3. With the help of the transfer station 26, the enamelled goods can be removed from the belt 3 and lifted onto the connecting belt 5. The movement of the stacker member 24 which is taking place is shown in FIG. 3b by a movement diagram. The tines 23 first drive into the alleys between the webs 20 (movement phase 1); then they are raised a bit (movement phase 2) and withdrawn together with the standing enamelled goods (movement phase 3). This is followed by a lowering (movement phase 4), whereby the enamelled goods standing on the tines are placed on the connecting belt. The tines then move back (movement phase 5) and rise back to the starting position (movement phase 6).

In addition to this arrangement with conveyor and connecting belts at different heights, it is also possible to maintain the same height of the conveyor and connecting belts. In this case (see FIG. 4) a transfer station 30 with a stacker element 24 is provided, which is provided with a rotatable head 31. The head can both extend and retract the stacker member 24 and rotate it through 90 ° so that it can be transferred from the conveyor belt 3 to a connecting belt 5. The underlying movement diagram (phases 1-6) is also shown in FIG. 4.

Another important aspect of the invention is the design of the webs 20, which form parts of the conveyor belts. The webs are made of a ceramic material or metal that meets the operating requirements. In particular, chrome-nickel steel is used in a heat-resistant, rustproof version. In FIG. 5 a, the webs 20 are fastened to belts 40 fastened transversely to the conveying direction on the conveyor chain, the belts lying parallel in pairs and carrying devices 41 on the top, in which the webs 20 can be removably stuck.

Another fastening option is provided in FIG. 5b. Here frame 42 are attached to the chain links, which consist of heat-resistant metals. The frames have a double L-profile 43 on one side and a C-profile 44 on the other side, whereby the webs 20 are connected at their base to an insertion strip 45 which is inserted into the C-profile, while the opposite side is simply set up on the transverse leg of the L-profile. In this embodiment, too, use has been made of the possibility of detachably connecting the webs to the insertion strip 45 and thus replaceably connecting them.

6, 6 a to 6 d finally show webs 20 according to further embodiments. The individual webs 20 consist of an ingot with a groove 33 into which a support element 34 is inserted. The shape of the support element 34 is reminiscent of a saw blade. It has a continuous, flat edge on its underside and a serrated shape on its top. The tines 35 form at their triangular converging tips the "singular contact surfaces" in the sense of the invention. For enamelled goods, the aim is to keep the contact area as small as possible.

The support elements 34 are provided with bores 36 (cf. FIGS. 6 a - d) which are held by holding rods 37, the holding rods 37 being pushed transversely through the bars and the bores 36. When the support elements 34 are replaced, the holding rods 37 are pulled out.

• a) das Halteelement besitzt an seiner Oberseite Zacken 35 in Sägezahnform, die sämtlich die gleiche Höhe besitzen.
• b) Die Zacken sind in Form einer konkaven Kontur angeordnet. Hierdurch wird ermöglicht, daß Emaillierwaren bestimmter Breitenausdehnung immer nur auf zwei in gleicher Höhe sitzenden Zacken 35' zu liegen kommen.
• c) Bei dieser Form des Auflageelementes sind Zacken 35" gewählt, die einen wesentlich größeren Abstand haben. In diesem Falle sind die Abstände angepaßt an die Waren, die auf den Auflageelementen zu liegen kommen.
• d) Das Auflageelement gemäß Figur 6 d weist einzelne Einsteckelemente 38 mit Spitzen auf, die in die Auflageelemente 34' in entsprechend gestaltete Bohrungen in gewünschter Anordnung eingesteckt werden können.

Various forms of the support elements are shown in FIGS. 6a-d:

• a) the holding element has serrations 35 in the shape of a saw tooth on its upper side, all of which have the same height.
• b) The prongs are arranged in the form of a concave contour. This enables enamel were certain width expansion only ever to lie on two teeth 35 'sitting at the same height.
• c) In this form of the support element, prongs 35 "are chosen which have a much greater distance. In this case, the distances are adapted to the goods which come to rest on the support elements.
• d) The support element according to FIG. 6 d has individual insertion elements 38 with tips which can be inserted into the support elements 34 'in appropriately designed bores in the desired arrangement.

Claims (6)

1. Device for drying and firing enamelled goods with an enamel application, with at least one drying oven and one continuous enamelling oven, as well as with a transport device running through the ovens and between the ovens, characterized in that the transport devices consist of at least one conveyor belt (3, 4, 5), which has singular contact surfaces distributed over the usable area of the belt, the contact surfaces taking up an arrangement in which alleys are formed between the contact surfaces, into which the tines (23) of a stacker member (24) can engage. 2. Device according to claim 1, characterized in that the conveyor belt by at least one of the ovens at least in sections consists of interconnected webs (20, 25) aligned parallel to one another in the conveying direction, the limbs distributed on their upper side provided with supporting surfaces, such as pins, Jagged and the like. 3. Device according to claim 1 and 2, characterized in that the support surfaces of a belt section span a concave contour in the conveying direction. 4. Device according to claim 2, characterized in that the webs (20) are designed as plate-like elements which are detachably connected to parts of the conveyor belt (Figures 5, 6). 5. Device according to claim 1, characterized in that the pins, prongs, etc. are removably connected to the webs of the conveyor belts. 6. Device according to claim 1-3, characterized by a conveyor belt through both types of ovens and a connecting belt (5) between the ovens (1, 2) wherein - the connecting belt is assigned to a furnace exit or entrance to a transfer device, the one has height-adjustable or rotatable stacker element (24) with tines.

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