CONVEYOR BELT FOR TUNNEL OVENS

Abstract: This invention is a conveyor belt for transporting bakery products inside a tunnel oven. This advancing-transporting device is composed of an assembly of conveyor belts of diverse types capable of carrying the products to be baked through the various areas of the oven chamber. The first conveyor belt (6), made of steel wire mesh, is situated at the front end of the oven where the products to be baked are placed before being transported into the baking chamber (5) where a second conveyor belt (7) is situated inside the baking chamber, and has a surface made up of parallelepipedon bodies placed transversally and opportunely spaced one beside the other, and which in turn are made up of elements made of different materials, more precisely; small bars (13) made of refractory material and a steel supporting and housing device for the bars (13). A further steel wire mesh conveyor belt (18) on the opposite side of the oven to the loading area, situated on a lower level in respect to the preceding conveyor belt (7) and on which the baked products come out of the oven through the exit (19).

Description: Description "Conveyor belt for tunnel ovens" Technical field This invention is a conveyor belt for transporting bakery products inside a tunnel oven. This advancing - transporting device is composed of an assembly of conveyor belts of diverse types capable of carrying the products to be baked through the various areas of the oven chamber. Technical status There are many different types of tunnel oven used for baking foodstuffs such as bread or other similar products, all of which are equipped with a large baking chamber with radiant heating elements (electric resistances) and a continuous conveyor belt system composed of a series of single rollers or small transporter bars that are laid transversally in regard to the oven channel and therefore perpendicularly to the direction in which the products that are to be baked are transported; the belts are activated through special systems and devices, for example, through a chain or roller transmission. These conveyor belts have an upper branch that serves to transport the products that are to be baked through the baking chamber with an almost uniform forward motion. If the conveyor belt is made of steel and is a single continuous belt that runs through the entire chamber of an oven heated by electric resistances, it will be heated in the baking chamber and cooled in the entering and exiting areas, and is therefore subject to a certain amount of thermal stress, which in turn creates the necessity for frequent, expensive maintenance work. In order to eliminate this inconvenience, in the past tunnel ovens with conveyor belts composed of small bars of refractory material have been proposed, for example, as in the American Patent US 5141379. The adoption of this material reduces the weight of the conveyor belt, makes it more resistant to brusque changes in temperature and also capable of supporting higher temperatures. Moreover, these bars are more resistant to attack by chemical agents. Unfortunately, the bars are made entirely of low elasticity refractory material; therefore, at the temperatures found in ovens with electric resistances, and with the mechanical stress caused by normal functioning, they become fragile and often break, especially in the areas where they are connected to each other and to the relative pulling devices. The aims of this invention The aim of this invention is to eliminate the inconveniences of the techniques already used to realise an automatic advancing - transporting system for bakery products that are to be baked, composed of one or more conveyor belts placed in line one after the other through the chamber of a tunnel oven and which together constitute a loading area, a baking area, a cooling area and an unloading area. Another aim of this invention, as stated in the preceding paragraphs, is to realise the following functipnal assembly: a) A steel conveyor belt situated at one end of a tunnel oven upon which the products to be baked are placed and through which the aforesaid products are introduced into the baking chamber of the oven; b) A conveyor belt that will transport the product to be baked horizontally along a route through the baking chamber, the surface of which is composed of parallelepiped bars laid parallel to each other, transversally and opportunely spaced, made of different elements, each of which is used in such a way that each type of material fully exploits the advantages of using refractory material together with steel; c) A further steel conveyor belt, placed on the opposite side to the loading area, on which the baked product exits from the oven through the exiting mouth. Another aim of this invention, in concordance with what is described in the preceding paragraphs, is that of realising a conveyor belt that can be closed inside the baking chamber of a tunnel oven, thus reducing heat dispersion and the mechanical stress to which conveyor belts are normally subject, and consequently reducing the deformation or breakages that normally make periodical substitution of the belt necessary. Another aim of this invention, in concordance with what is described in the preceding paragraphs, is to realise a supporting device and housing for small bars to be used as a part of conveyor belts made of refractory material for use in tunnel ovens. Another aim, associated with the advantages of the approach delineated in the preceding paragraphs, is to obtain a tunnel oven in which heat dispersion is particularly diminished, which allows cooking times to be reduced without detracting from the quality of the finished product or the flavour of the food that has been -baked, will always ensure uniform baking on all surfaces of the product, that can be used in comfort and is easy to maintain. A description of the attached drawings and the way in which this invention is realised Figure 1 is a three-dimensional view of the complete tunnel oven, with the route taken by the conveyor belts traced in dotted lines. Figure 2 is a lateral view of the oven showing how the three conveyor belts are aligned (traced in dotted lines) in the oven chamber. Figure 3 is a lateral view of the three conveyor belts, demonstrating their planned movement. Figure 4 is a front view of the entering conveyor belt, which is made of steel wire mesh. Figure 5 is a diagram of a detail of the pulling roller that activates the wire mesh belt. Figure 6 is a diagram of the conformation of a small bar made from refractory material. Figure 7 is a lateral view of the conformation of a small bar made from refractory material. Figure 8 is a front view of the conformation of a small bar made from refractory material. Figure 9 is a three dimensional view of one end of a small bar made from refractory material. Figure 10 is a three dimensional view of the supporting device and housing for the small bars made from refractory material. Figure 11 is a three dimensional view of the assembly of the supporting device with a small bar attached to it. In the form of realisation of this invention described above and also in the attached drawings, (1) indicates the external lateral panelling of the oven, which can be easily removed to allow maintenance work to be carried out, with four feet (2) equipped with wheels (3) that can be regulated to attach the oven to the floor or to allow the oven to be moved easily around the factory floor to a different location. A functional switchboard (4) that can be oriented in various directions permits the operator to work from diverse positions; the temperature is set by a digital thermo regulator situated on the switchboard (4) which is also equipped with a display for visualising the temperature (max. 700°C.) inside the baking chamber; the electric power, commutable from 24 to 50 KW, can be regulated both at roof and the bedplate levels of the oven in order to adapt the temperature more precisely for the product that is to be baked. The products to be baked enter the baking chamber (5) on a steel wire mesh conveyor belt that starts at the loading area where the products enter the oven. This conveyor belt is cooled by a fan of the open vane type. The baking chamber is equipped with heating elements composed of electric resistances situated directly above and below the baking area and which are adequately covered with insulating material so as to limit transportation of heat to the outer parts of the oven. Situated where the products to be baked reach the limit of their forward motion on this first conveyor belt, is a second conveyor belt (7) composed of an assembly of steel supports and elements in refractory material laid on the former in order to ensure that the products placed on the conveyor belt are baked evenly as they transit through the oven chamber or baking area, given that they cannot be turned and therefore the same surface is always exposed to the heat sources. An assembly conceived in this way also ensures greater resistance to mechanical stress on the part of the conveyor belt itself. Each of the supporting elements is made up of a parallelepipedon bar in steel C-section (8); a hollow seating (9) with a quadrangular cross- section, the mouth of which is tapered to a sharp edge (10), which is soldered to each end of the bars and the rear part of which is equipped with an L-cross- ^ section plate (11); on the free surface of this there is a hole (12) into which a fastening element can be inserted. The ends of the bars (13) are inserted into these housings (9). The bars (13) are cylindrical and are made of specially shaped refractory material in a single piece, the central portion of which is rectangular (14); the lateral surface (15) of the bar is in the shape of a trapezoid isosceles with 45° oblique margins and two rectangular shaped ends (16) that are slightly smaller than the central part (14). The lateral surfaces (15) and (16) and the upper surface (14) of these bars are all flat, while the lower surface is shaped with a series of embossments (17) arranged in a semicircle. The baked product exits the oven on a further wire mesh conveyor belt ( 18) situated at a lower level in respect to the preceding conveyor belt (7) at the opposite end to the loading area (20) of the oven. At the top of the exiting or unloading (19) end of the oven there is an oven hood (21) which cools the products as they arrive at the unloading area. It is possible to vary the transportation speed of the products to be baked as well as the type of baking required in order to ensure that the products are in the oven baking chamber for an optimum length of time, according to the product and the type of baking required. The mechanical handle emergency device (22) situated on one side of the oven is particularly useful as it permits the user to extract the product from the oven in case of a power blackout. As can be clearly seen the invention fulfils its objectives completely. All the details can be substituted according to necessity by other elements with the same technical characteristics, essentially the dimensions and shapes can be varied according to the user's requirements.

Claims: Claims 1) An automatic advancing - transporting system for food products to be baked, composed of various conveyor belts placed in line one after the other along a route through a tunnel oven to make up a loading area, a baking area and a cooling area, characterised by the fact that: a) the first conveyor belt (6), made of steel wire mesh, is situated at the front end of the oven where the products to be baked are placed before being transported into the baking chamber (5) where b) a second conveyor belt (7) is situated inside the baking chamber, and has a surface made up of parallelepipedon bodies placed transversally and opportunely spaced one beside the other, and which in turn are made up of elements made of different materials, more precisely: small bars (13) made of refractory material and a steel supporting and housing device for the bars (13). c) A further steel wire mesh conveyor belt (18) on the opposite side of the oven to the loading area, situated on a lower level in respect to the preceding conveyor belt (7) and on which the baked products come out of the oven through the exit (19). 2) An automatic advancing - transporting system for food products to be baked as in claim 1), characterised by the fact that each of the supporting and housing devices for the bars (13) is made up of a parallelepipedon bar in steel C-section (8), at both ends of which is soldered a rectangular cross-section hollow housing (9), the mouth of which is tapered to a sharp edge (10), and the rear end of which is equipped with an L cross-section plate (11) on the free surface of which is a hole (12) into which a fastening element can be inserted. 3) An automatic advancing- transporting system for food products to be baked as in claims 1) and 2) characterised by the fact that the ends (16) of the bars (13) made of refractory material can be inserted into each housing (9). 4) An automatic advancing - transporting system for food products to be baked as in claims 1) and 3), characterised by the fact that the bars (13) are composed of a parallelepipedon bar in refractory material, in a single specially shaped piece, composed of a rectangular central part (14), the lateral surface (15) of which is in the shape of a trapezoid isosceles with 45° degree oblique margins, and two rectangular ends (16) that are slightly smaller than the central part (14). 5) An automatic advancing - transporting system for food products to be baked as in claims 1) and 4), characterised by the fact that the lateral and upper surfaces of the bars (13) are flat, while the lower surface is shaped with a series of embossments (17) arranged in a semicircle. 6) An automatic advancing - transporting system for food products to be baked as in claim 1), characterised by the fact that the conveyor belts (6), (7) and (18) can proportionally and equally vary the speed of their movement through the oven chamber. AMENDED CLAIMS [received by the International Bureau on 7 January 2002 (07.01.02); original claims 1-6 replaced by new claims 1-5 (2 pages) 1 ) An automatic advancing - transporting system for food products to be baked, composed of various conveyor belts placed in line one after the other along a route through a tunnel oven to make up a loading area, a baking area and a cooling area, characterised by the fact that: the surface of the conveyor belt (7) made up of parallelepipedon bodies placed transversally and opportunely spaced one beside the other, and which in turn are made up of elements made of different materials, more precisely: small bars ( 13) made of refractory material and a steel supporting and housing device for the bars (13). 2) An automatic advancing - transporting system for food products to be baked as in claim 1) characterised by the fact that each of the supporting and housing devices for the bars (13) is made up of a parallelepipedon bar in steel C-section (8), at both ends of which is soldered a rectangular cross-section hollow housing (9), the mouth of which is tapered to a sharp edge (10), and the rear end of which is equipped with an L cross-section plate (11) on the free surface of which is a hole ( 12) into which a fastening element can be inserted. 3) An automatic advancing- transporting system for food products to be baked as in claims 1) and 2) characterised by the fact that the ends (16) of the bars (13) made of refractory material can be inserted into each housing (9). 4) An automatic advancing - transporting system for food products to be baked as in claims 1) and 3), characterised by the fact that the bars (13) are composed of a parallelepipedon bar in refractory material, in a single specially shaped piece, composed of a rectangular central part (14), the lateral surface (15) of which is in the shape of a trapezoid isosceles with 45° degree oblique margins, and two rectangular ,ends (16) that are slightly smaller than the central part (14). 5) An automatic advancing - transporting system for food products to be baked as in claims I ) and 4), characterised by the fact that the lateral and upper surfaces of the bars (13) are flat, while the lower surface is shaped with a series of embossments (17) arranged in a semicircle.

Inventors: CAROCCIA SAVERIO, CAROCCIA, SAVERIO
Applicants: CAR FORNI SRL SA, CAROCCIA SAVERIO, CAROCCIA, SAVERIO, SA.CAR FORNI SRL.
Application year: 2000
Main classification: A21B1
IPC codes: A21B1, B65G15