ITRE20000096A1 - COOKING OVEN FOR CERAMIC TILES WITH PERFECTED COOLING SECTION - Google Patents

Description

DESCRIPTION

of the Italian Patent for Industrial Invention entitled: "COOKING FURNACE FOR CERAMIC TILES WITH SECTION OF

PERFECTED COOLING ",

The present invention relates to kilns for firing ceramic tiles, and in particular to the cooling section for ceramic products, such as for example tiles, located in correspondence with the end zone of the kiln.

Known kilns, in particular those intended for firing ceramic tiles, have a tile cooling zone near the outlet. In particular, said cooling zone comprises at least three chambers, and precisely a first chamber, located immediately downstream of the cooking zone of the oven, called rapid cooling, a second chamber called slow cooling, and finally in a third chamber called di final cooling.

In these cooling zones, the tiles, which are arranged on several parallel rows and are moved forward thanks to a motorized roller conveyor, are lapped with a flow of ambient air introduced into the chamber by a plurality of distributing pipes, whose axis is transverse to the direction of advancement of the tiles themselves. Said distributors are arranged both above and below the roller conveyor and are equipped with a plurality of holes designed to direct the air jet orthogonally to the direction of advancement of the tiles in the chamber so as to touch both the larger surfaces of the tiles themselves.

In the so-called rapid cooling zone, i.e. the zone of the kiln which is immediately downstream from the cooking zone, it has been found that by adjusting the flow rate of the refrigerant flow (ambient air) it is possible to correct any defects in the planarity of the tiles.

Adjusting the flow rate of the refrigerant fluid in combination with the usual distribution pipes, while working perfectly with small tile formats, is not sufficient to correct any flatness defects in large format tiles, i.e. tiles with dimensions greater than 30X30 cm. This is largely due to the fact that the distributing pipes transversal to the feed motion, for reasons of space, cannot be placed at a distance so close enough to have a sufficient density of nozzles in the direction of advancement of the tiles. Furthermore, the use of distributing pipes transversal to the movement of advancement of the tiles does not allow to differentiate the cooling in the cross section of the kiln.

The object of the present invention is to overcome the drawbacks known to the art in the context of a rational and effective solution, and the cost of which is contained.

The invention achieves the said and other objects thanks to an oven whose cooling zone, in particular the rapid cooling zone, of the tiles is equipped with a cooling system which comprises, in addition to the usual first refrigerant fluid distributing pipes arranged transversely to the direction of advancement of the tiles, at least also a second distributor means whose axis is substantially arranged in the direction of advancement of the tiles, and whose nozzles are oriented in such a way as to direct the flow of refrigerant fluid in the direction of one of the larger surfaces of the floor tiles.

Said at least one distributor means can be placed both below and above the tiles, and the delivery of the refrigerant fluid is regulated by suitable flow throttling devices (valves).

In a preferred embodiment, said at least one second distributor means are a plurality of distributor means arranged both under the conveyor of the tiles and above it.

The regulation of the flow rate of the refrigerant fluid delivered by said second distributing means takes place according to the planarity deformations that the tiles exhibit at the kiln outlet.

The. arrangement of said second distributing means allows the nozzles to be placed at a close distance, which varies between 20 and 40 mm, a distance that cannot be equaled by using the usual transversal distributing pipes, due to the minimum distance between the pipes themselves. advantageously, a greater effectiveness of the action of the cooling fluid on the surface of the tile is obtained.

Furthermore, the arrangement of said second distributor means, the axis of which is substantially parallel to the direction of advancement of the tiles, allows the invention to achieve a second important advantage which consists in the possibility of differentiating the cooling of the tiles along the cross section of the cooling zone. of the oven.

According to a variant of the first embodiment of the invention, the rapid cooling zone of the furnace has only the said second distributor means, the first transverse distributors being absent.

The peculiar characteristics of the invention are recited in the claims.

In order to better clarify the constructive and functional characteristics of the invention, a preferred embodiment is described below, given by way of non-limiting example and illustrated in the attached drawing tables.

Fig. 1 shows a cross section of the cooling zone of the furnace according to the invention.

Fig. 2 is the section II-II of Fig.l.

Fig. 3 is the section III-III of Fig.l.

Fig.4 shows a cross section of the cooling zone of the furnace, according to a variant of the invention. Fig.5 is the V-V section of Fig.4.

The aforementioned figures 1, 2 and 3 show the rapid cooling zone 1 of the tunnel kiln 2, which is located immediately downstream of the firing zone of the kiln, not shown as it is usual in itself.

The tunnel kiln 2 is traversed by a roller conveyor 3, known per se, on which the tiles 4 arranged in several parallel rows are placed.

In the rapid cooling zone 1 there is the tile cooling system 4, which comprises two alignments G and the usual distribution pipes 8, whose axis is transverse to the direction of advancement of the tiles 4, and two alignments 9 and 10 of distributing means 11, the axis of which is oriented in the same direction of advancement of the tiles 4 inside the rapid cooling zone 1.

In the description of the embodiment of the invention, said distributing means have the shape of circular section ducts or pipes.

In particular, each of the alignments 9 and 10 comprises, in the illustrated embodiment of the invention, two groups of three distributor tubes 11, arranged in proximity to the side walls 20 of the oven 2.

Each of the distributing pipes 8 and 11 has a plurality of distributing nozzles 12 facing the tiles 4 to be cooled. With reference to Fig. 1, the distributing pipes 8 and 11 of the alignments 6 and 9 are turned downwards so as to direct the cooling fluid on the upper surface of the tiles 4, while the distributing pipes 8 and 11 have the nozzles 12 facing upwards in order to direct the refrigerant fluid (ambient air) on the upper surface of the tiles 4.

The distance between the nozzles 12 of the distributing pipes 8 and 11 preferably varies between 20 and 40 mm.

The distributing pipes 11 are connected to a manifold 13, a throttle valve 14 being interposed between each distributor pipe and the collector 13. The manifold 13, in turn, communicates by means of a valve 15, a flow throttle, with a fan, not shown , of delivery of the refrigerant fluid, generally air at room temperature.

The distributing pipes 8, on the other hand, are connected to a manifold, not shown, which is fed with refrigerant fluid, through a usual delivery device (fan), not shown as it is known per se.

The operation of the invention is very simple. In fact, the delivery of the refrigerant fluid from the distribution pipes is regulated on the basis of the flatness defects that the tiles present once they have cooled. Depending on the type of geometric defect of the tile, it is possible to adjust the flow rate that comes out of certain distributing pipes 8 and 11, or from alignments 6, 7, 910.

For example, if the tiles, once cooled, have a convexity facing downwards, the cooling action on the lower face of the tile increases in order to correct the flatness defect.

Figures 4 and 5 illustrate a variant of the first embodiment of the invention.

The aforementioned figures show the rapid cooling zone 20 of the tunnel kiln 21, which is crossed by a usual motorized roller conveyor 22 for transporting the tiles 23. More in detail, the tiles 23 are arranged on the roller conveyor 22 in parallel rows.

In the rapid cooling zone 20 there is the tile cooling system 23, which comprises two alignments 24 and 25 of distributing means 26 arranged respectively above and below the roller conveyor 23. In the illustrated embodiment of the invention, distributing means 26 are a plurality of distributing tubes whose axis is parallel to the direction of advancement of the tiles in the rapid cooling zone 20 of the kiln. Each of the two alignments 24 and 25 is connected to a delivery manifold 27 for the refrigerant fluid, usually air at room temperature, a device (valve) 28 for the flow of fluid being interposed between each of the distribution pipes 26 and said manifold 27. coolant, externally adjustable.

The manifold 27 is in turn put into communication with an external conduit 29 for delivery of the refrigerant fluid through a throttle valve 30.

The refrigerant fluid is fed to said external duct 29 and therefore to the distribution pipes 26 by a usual fan, not shown.

Each of the pipes 26 is equipped with a plurality of nozzles 260 oriented in such a way as to direct the flow of cooling fluid in a direction substantially orthogonal to the direction of advancement of the tiles 23 in order to be able to lap the two larger faces of the tiles themselves.

The operation of the variant of the invention is entirely similar to the operation, already described, of the first embodiment of the invention, therefore the description thereof is omitted. It should be noted that in the embodiments of the invention described and illustrated in the drawings, the distributing pipes 8, 11, and 26 have a circular section, but they can obviously be made as ducts having non-circular sections, for example square or rectangular.

Claims (6)

CLAIMS 1. Improved cooling section of a kiln for firing ceramic tiles, crossed by a usual motorized roller conveyor for transporting the tiles, and comprising a cooling fluid delivery fan adapted to supply at least two fluid distributing means, of which at least one is placed below said motorized roller conveyor and is able to send refrigerant fluid against the lower surface of the tile, and at least one other is placed above said roller conveyor and is able to send refrigerant fluid against the upper surface of the tile, characterized by fact that the axis of at least two of said distributing means is substantially parallel to the direction of advancement of the tiles inside the kiln. 2. Cooling section according to claim 1, characterized in that each of said at least two distributing means, parallel to the direction of advancement of the tiles inside the kiln, is put into communication with the said cooling fluid delivery fan by means of a throttle device (valve) which allows to regulate the delivery of the flow of refrigerant fluid so as to differentiate the action of said fluid in the cross section of the cooling section of the furnace. 3. Cooling section according to claim 1, characterized in that each of said distributing means, parallel to the direction of advancement of the tiles inside the kiln, has a plurality of aligned nozzles. 4. Cooling section according to claim 3, characterized in that the center distance of said nozzles is comprised between 20 and 40 mm. 5. Cooling section according to claim 1, characterized in that each of said distributing means, parallel to the direction of advancement of the tiles inside the kiln, comprises two alignments of distributing pipes with circular section. 6. Cooling section according to claim 1, characterized in that said distributing means, parallel to the direction of advancement of the tiles inside the kiln, are associated with distributing means whose axis is orthogonal to the direction of advancement of the tiles at the inside the oven.