FR2974788A1 - CARPETS FOR TRANSPORTING PRODUCTS IN A TUNNEL FURNACE - Google Patents

Abstract

The mat consists of lateral link chains (7) and transverse bars (8) which form a transport surface (11). This transport surface is composed of a succession of distinct carrier parts (12) which are separated by an intermediate part (14). Each carrier part (12) comprises a group consisting of at least one pair of bars (8) which are interlaced by at least one wire (13) wound helically. The portion (14) intermediate between two groups of bars (8) interleaved preferably corresponds to twice the space between two adjacent bars (8) of the same group of bars (8) intertwined.

Description

CARPETS FOR TRANSPORTING PRODUCTS IN A TUNNEL FURNACE

The present invention relates to a carpet used for transporting products in a tunnel furnace.

It relates, more particularly, a carpet for a tunnel furnace which is used in the field of the packaging of products like flasks, bottles, etc., after a shrinkwrapper, in order to heat shrink the plastic film which envelops the batch of products.

State of the art This type of furnace tunnel is described in particular DE 10 20 08019774. It comprises an endless metal belt on which are deposited the batches of products after their coating with a heat-shrinkable plastic film at the outlet of the shrinkwrapper and this endless belt passes through the tunnel furnace to perform the heat shrink operation before delivering the wrapped products by the heat shrunk film to a supporting conveyor belt, at the exit of this tunnel furnace. In order to heat shrink the plastic film, the tunnel furnace comprises heating elements which make it possible to reach a temperature which is between 150 and 200 ° C. according to the products and according to the type of plastic film; generally this temperature is of the order of 170 ° C. During its passage in the tunnel furnace, the metal endless belt absorbs a good part of this thermal energy and it diffuses it between the output of said tunnel furnace and the entrance of this same furnace. This carpet is an important source of energy dispersion in the oven.

It is known, as described in US 5,651,449, to use a special mat that provides substantial savings in energy. This mat includes side chains and, between these chains, it comprises transversely arranged bars, which bars are made of a thermally insulating material. This kind of composite carpet offers a good carrier surface and allows a passage of all types of products in the tunnel furnace; however, it is specially manufactured and is relatively complex and expensive.

OBJECT OF THE INVENTION The present invention provides a carpet for transporting products in a tunnel furnace and, in particular, products which inherently benefit from good stability, as is particularly the case for a batch of products where said products are placed on a rigid cardboard sheet or a relatively rigid tray and / or installed in a half-box or other. The carpet according to the invention, for batches of products that are relatively stable, allows significant energy savings through a significant reduction of the metal components involved in making the carrier surface of said carpet.

SUMMARY OF THE INVENTION The invention relates to a conveyor belt for products in a tunnel furnace which is arranged after a shrinkwrapper, and in particular a conveyor belt for products grouped together in relatively batch form. stable, which mat consists of link side chains and a transport surface having transverse bars extending between said links, said transport surface comprises an alternation of bearing parts and intermediate parts which are non-bearing said carrier portions consist of a group of bars which comprise at least a pair of bars which are intertwined by at least one helically wound wire, and said intermediate parts are free, in whole or in part, of interlacing, thus forming a free space, without metal masses, to significantly reduce the mass of the components of said carrier surface and its thermal inertia than. Still according to the invention, the spacing between two adjacent bars of the same group, corresponds to the spacing of the axes of the links of the chains, which spacing is of the order of 12.7 mm. According to another embodiment of the invention, the intermediate portion between two groups of interleaved bars corresponds to twice the distance between two adjacent bars of the same pair of interleaved bars. Still according to the invention, the intermediate portion comprises, between two groups of interleaved bars, a complementary bar. According to another embodiment of the invention, the belt comprises, in the intermediate part, between two adjacent bars, at least one connecting member which provides a certain rigidity of the bearing surface in the longitudinal direction. Still according to the invention, the interlacing of each pair of bars is achieved by means of a wire whose diameter is of the order of 1.2 mm and the angle of the helix of said interleaving wire. is of the order of 30 °. According to another embodiment of the invention, the bars consist of solid rods whose external diameter is of the order of 3.9 mm. According to an alternative embodiment, the bars are of the tubular type with an outside diameter of the order of 4 mm and an inside diameter of about 2 mm. Still according to the invention, the bars are metallic. According to an alternative embodiment, the bars are made, in whole or in part, of thermally insulating material such as carbon fiber, fiberglass, aramid fiber ("KEVLAR") or others. DESCRIPTION OF THE FIGURES In order to be able to be executed, the invention is described in a sufficiently clear and complete manner in the following description which, in addition, is accompanied by 20 drawings in which: FIG. 1 shows, schematically, a tunnel furnace which comprises an endless belt for conveying the products, and in particular batches or groups of self-stable products, inside said tunnel furnace; - Figure 2 shows schematically and partially a portion of a product conveyor belt according to the invention; - Figure 3 shows, in perspective, a portion of the conveyor belt shown in Figure 2; FIGS. 4 and 5 show an alternative embodiment of the batch conveyor belt produced according to the invention. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 schematically shows a tunnel furnace 1 crossed by batches of products 2. These batches of products 2 arrive, for example, from a shrinkwrapper (not represented) and are transported to 1 in the oven-tunnel 1 by means of a conveyor belt 3 which is partially shown in FIG. 1. This conveyor belt 3 deposits the batches of products 2 which are surrounded by a plastic film 4, on the carpet 5 without end of the tunnel furnace 1, which endless belt 5 passes through said tunnel-oven 1 over its entire length and, at the outlet of the latter, it transfers the batch of coated products 2 on a carpet 6 of support. The endless belt of tunnel furnace 1, as partially shown in FIG. 2 and, in perspective, FIG. 3, comprises chains 7 which are arranged laterally, which chains are spaced apart by a distance which is of the order of 800 mm. to form a useful surface on which are arranged the batches of products 2. These endless chains 7 are interconnected by transverse bars 8 whose ends are, for example, embedded in the hollow axes 9 of the links 10 of each chain 7 The chains 7 are conventional chain-link chains 10 with, for example, a pitch and spacing of about 12.7 mm between the axes 9. The batch of products 2, represented by its partial contour, in fine mixed lines, Figure 2, rests on a transport surface 11 which comprises an alternation of 30 parts which are carriers and intermediate parts which form a void or almost empty surface, without thermal inertia.

In the embodiment of Figures 2 and 3, each carrier portion 12 comprises a group of two bars 8 which forms a pair, and these two bars 8 are interlaced by a wire 13 which is generally a wire, which wire 13 is wound in a helix on the bars 8 which form a pair of bars, and it is this wire 13 which forms the flat transport surface on which the batches of products 2 rest. To reduce the metal masses, the intermediate parts 14 situated between two parts 12 carriers, form a free space, which space is, in fact, a space which is free of interlacing, and this free space extends over all or part of the area which is delimited by the lateral chains and by the parts 12 carriers, thereby reducing, singularly, the metal masses of the carpet 5. In the embodiment shown in Figures 2 and 3, the reduction of metal masses results from the absence of a bar 8 between two parts 12 p orteuses.

Indeed, in these figures 2 and 3, on a sequence of three axes 9 of the chain 7, only two axes 9 comprise a bar 8. This intermediate portion 14 extends longitudinally over a distance which corresponds to twice the pitch, or center distance, links 10 of the chain 7.

Thus, it saves one bar on three and 8, especially, it saves two threads of interlacing 13 out of three, compared to a conventional carpet which has a bar 8 fixed at each axis 9 of the links 10 of the chain 7.

In a first embodiment, the bars 8 are metallic and they have, for example, a diameter of the order of 3.9 mm. They may also be in tubular form with an outer diameter of about 4 mm and an internal diameter of about 2 mm. The interlacing wire 13 is metallic and may have a diameter of the order of 1.2 mm with an angle α of helix which is, for example, of the order of 30 °. FIG. 4 and FIG. 5 show an alternative embodiment of the belt 5 which serves to transport batches of products 2. In this variant, the reduction in the number of bars 8 is one in four and the reduction in the number of wires 13 is two out of four. This type of belt 5, provided with groups of bars 8 which consist of three consecutive bars 8, offers relatively larger portions 12 'carriers, better suited to heavy products. The intermediate portion 14 between two groups of bars 8 is identical to those of Figures 2 and 3 above; it corresponds to twice the pitch, or the center distance, of the links 10 of the chain 7. In this variant, represented in FIGS. 4 and 5, the bars 8 are also fixed, as previously, on the axes 9 of the links 10 of the chains. 7, and they are also intertwined by pairs of bars 8 with the same wire 13 as before. As before, these bars 8 may be metallic, in the form of solid rods with a diameter of the order of 3.9 mm; they may also be in tubular form with an outer diameter of about 4 mm and an internal diameter of about 2 mm. As previously, the wire 13 used to interleave two adjacent bars 8, is a wire whose diameter is of the order of 1.2 mm and the winding angle a is, for example, of the order of 30. °.

It can be seen in FIGS. 4 and 5 that the angle α of the helix is inverted for each pair of bars 8, in the case of a group consisting of three bars 8. According to an alternative embodiment, the bars 8 may be made of a thermally insulating material, of the carbon fiber type, fiberglass, aramid fiber ("Kevlar") for example, or other. FIG. 4 shows an alternative embodiment of the invention which consists in inserting a connecting member 15 between the bars 8 of two adjacent carrying parts 12, which connecting member is, for example, in the form of of a staple, which clip is disposed in the intermediate portion 14, between two bars 8 to achieve a better rigidity of the belt in the longitudinal direction. FIG. 3, and FIG. 4 also, show an alternative embodiment of this conveyor belt 5, in which the intermediate portion 14 comprises a bar 8 'which is positioned between the chains è, fixed on the axes 9 which are free, which complementary bar 8 'can, in a certain way, play a role for the transport of the products 2; this bar 8 'also serves as a relay for the installation of a pair of connecting members 15', also in the form of staples, which members 15 'of connection make the junction, through the bar 8' between the bars 8 of two adjacent carrier portions 12. This results in a greater rigidity of the belt 5 in the longitudinal direction, and in particular, its transport surface 11.

Several members 15, 15 'can be distributed and installed in the intermediate portions 14, between the side chains 7, as required.

Claims (11)

CLAIMS1 - Carpet for transporting products in a tunnel furnace, of the type consisting of side chains with links and a transport surface comprising transverse bars which extend between said links, characterized in that said transport surface comprises a alternating portions (12) which are carriers and intermediate parts (14) which are non-load bearing, said carrier portions (12) consist of a group of bars (8) which comprises at least one pair of bars (8) which are intertwined by at least one helically wound wire (13), and said intermediate portions (14) are free, in whole or in part, of interleaving. 2 - Carpet products in a tunnel furnace, according to claim 1, characterized in that the spacing between two adjacent bars (8) of the same group, corresponds to the spacing between the axes (9) of the links (10) chains (7), which spacing is of the order of 12.7 mm. 3 - conveyor belt for products in a tunnel furnace, according to claim 2, characterized in that the portion (14) intermediate between two groups of bars (8) interleaved is twice the distance between two bars ( 8) adjacent to the same pair of bars (8) interlaced. 4 - conveyance of products in a tunnel furnace, according to claim 3, characterized in that the portion (14) intermediate comprises, between two groups of bars (8) interleaved, a bar (8 ') complementary. 5 - Carpet products transport in a tunnel furnace, according to any one of claims 3 or 4, characterized in that it comprises, in the portion (14) between two intermediate bars (8 or 8 ') adjacent at least one connecting member (15, 15 ') which provides a rigidity of the bearing surface in the longitudinal direction. 6 - Product transport mat in a tunnel oven, according to any one of claims 1 to 5, characterized in that the interlacing of each pair of bars (8) is achieved by means of a wire (13) metal whose diameter is of the order of 1.2 mm. 7 - Carpet products in a tunnel furnace, according to claim 6, characterized in that the angle of the helix of the wire (13) interlacing is of the order of 30 °. 8 - conveyor belt for products in a tunnel furnace, according to any one of claims 1 to 7, characterized in that the bars (8, 8 ') consist of solid rods, the outer diameter of which is order of 3.9 mm. 9 - Carpet products transport in a tunnel furnace, according to any one of claims 1 to 7, characterized in that the bars (8, 8 ') are of the tubular type with an outer diameter of about 4 mm and an inside diameter of the order of 2 mm. 10 - Carpet products in a tunnel furnace, according to any one of claims 8 or 9, characterized in that the bars (8) are metallic. 11 - Carpet for transporting products in a tunnel furnace, according to any one of claims 8 or 9, characterized in that the bars (8) are made of thermally insulating material such as carbon fiber, fiberglass aramid fiber ("KEVLAR") or others.