EP1640130A1 - Method of manufacturing a honeycomb structural body of fired clay - Google Patents

Abstract

The method involves making two transversal cuts on an extruded terra cotta unit (5), where the distance between the transversal cuts formed on the unit is equal to a length of a green product (8) to be obtained. The cut at a free end of the unit is provided with, between the unit and end, a footing (18) supporting the product during handling and drying phases. An independent claim is also included for a device for manufacturing terra cotta unit based on a terra cotta manufacturing method.

Description

The present invention relates to a method of manufacturing earthenware elements having parallel cells.

These terracotta elements, such as chimney plugs, and hollow hollow bricks, which are increasingly used for their good sound and thermal insulation properties, are obtained by spinning clay which is kneaded in a kneader. screw, then extruded through a die, and finally cut to obtain the semi-finished elements, called "green products".

These green products are then dried, generally in forced air dryers in laminar flow.

In very many cases, the extrusion is carried out horizontally. However, it appeared that the earth, not yet solidified because not dried out of die, sags by gravity, which causes irreversible deformation of the product; even a collage of the cell walls between them.

To solve this problem, vertical extrusion is sometimes carried out, with the removal of the green products on drying racks at the outlet of the die, so as to support the green product (deformable) in the direction of its strongest rigidity (gravity in the direction of the extrusion of the partitions).

• réduction de la "terre sèche" génératrice de déchets de fabrication, le positionnement vertical de la mouleuse - ou extrudeuse - permettant son alimentation gravitaire et la suppression des piocheurs de gavage des hélices d'extrusion, sources de terre sèche,
• réduction du jeu entre hélice et corps de mouleuse en vue de réduire la re-circulation de terre vers l'arrière de la mouleuse sous l'effet de la pression du mélange argileux dans le gueulard de la mouleuse, cette re-circulation de terre s'accompagnant de frottements donc de pertes énergétiques se caractérisant par un échauffement du corps de mouleuse pouvant atteindre des températures supérieures à 50°C génératrices de terre sèche,
• agrandissement au maximum des diamètres d'hélice d'extrusion de façon à obtenir une réduction des vitesses de l'élément extrudé, favorable à la réduction des usures d'hélices et des consommations énergétiques,
• simplification et diminution des vitesses de manutention de produits verts afin de minimiser les déformations desdits produits verts (qui ont habituellement un taux d'humidité de l'ordre de 20%).

Other advantages of vertical extrusion are:

• reduction of "dry land" generating manufacturing waste, the vertical positioning of the molding machine - or extruder - allowing its gravity feed and the removal of booster diggers from extrusion propellers, sources of dry land,
• reducing the clearance between the propeller and the molding body in order to reduce the recirculation of earth towards the rear of the molding machine under the effect of the pressure of the clay mixture in the mold's throat, this recirculation of earth accompanying friction thus energy losses characterized by a heating of the molding body that can reach temperatures above 50 ° C generating dry earth,
• maximum enlargement of the extrusion helix diameters so as to obtain a reduction in the speeds of the extruded element, favorable to the reduction of helix wear and energy consumption,
• simplification and reduction of the handling speeds of green products in order to minimize the deformations of said green products (which usually have a moisture content of the order of 20%).

Technical solutions have been proposed for the vertical extrusion of terracotta elements, as described in documents US 663,141, FR 1,580,652, and EP 284,309 B2.

Nevertheless, in all the cases described in the prior art, the green products that are cut at the die outlet are deposited on transport trays and rest on their lower end. It has appeared that at this end appear deformations due to the mass of the green product itself, which deforms the still malleable material at the lower end of said product. There is then a flare of the end of the green product in contact with the rack, which is obviously detrimental.

In addition, it is very often noted, during drying, the appearance of cracks from the surface of the green product in contact with the rack, which spread over a few centimeters, and mechanically weaken the product.

• (i) extruder verticalement en continu de la matière à travers une filière de manière à former un élément extrudé,
• (ii) amener en appui l'extrémité de l'élément extrudé contre une claie portée par un plateau formant support horizontal,
• (iii) réaliser la découpe transversale de l'élément extrudé pour former un produit vert, en même temps que le plateau horizontal est déplacé de haut en bas à la vitesse d'extrusion de la matière.

The present invention provides a solution to the technical problems mentioned above, with a method of manufacturing terracotta elements comprising parallel cells, consisting of:

• (i) continuously extruding the material vertically through a die to form an extruded member;
• (ii) bringing the extremity of the extruded element into abutment against a shelf supported by a horizontal support plate,
• (iii) cross-cutting the extruded member to form a green product, at the same time that the horizontal platen is moved up and down at the extrusion speed of the material.

More specifically, the method according to the invention is characterized in that it consists in making two transverse cuts of the extruded element to form a green product, the distance between the two cuts being equal to the length of the green product to obtain, the cutout located on the side of the free end of the extruded material leaving between itself and said free end, a soleplate intended to serve to support the product during the handling and drying phases.

The unitary element, brick or chimney plug, for example, which has been cut from the continuously extruded clay vein, is called a "green product".

The lost sole created at the interface between the green product and the rack, will itself undergo the deformations due to the mass of the green product located above it, as well as any cracks mentioned above. Green products are therefore not deformed and dry products do not crack.

Advantageously, after complete cutting of a green product, the drying thereof is carried out by pulsating hot air through the orifices of the screen, parallel to the cells.

• une trémie et une vis d'alimentation en terre d'une filière pour l'extrusion verticale d'un élément en terre,
• un plateau mobile selon un axe vertical et disposé en regard de la filière formant support pour une claie de transport d'un produit vert,
• des moyens de découpe de l'élément extrudé pour former le produit vert,
• des moyens de transfert de la claie portant le produit vert en direction d'un poste de séchage et des moyens de transfert d'une claie vide sur le plateau support.

The present invention also relates to a device for the manufacture of terracotta elements, according to the method described above, device comprising:

• a hopper and a feed screw of a die for the vertical extrusion of an earth element,
• a plate movable along a vertical axis and arranged facing the die forming a support for a rack for transporting a green product,
• means for cutting the extruded element to form the green product,
• means for transferring the rack carrying the green product to a drying station and means for transferring an empty rack to the support plate.

More particularly, the device of the invention is characterized in that the cutting means comprise two vertically superposed yarns at a distance from one another, equivalent to the length of the green product to be obtained, these cutting means being integral with the support plate, so as to accompany the descent of the extruded material during the cutting phase.

In the description which follows, the term "son" will be used for the cutting means, which is a generic term designating two elements whose thickness is very small, at least in the direction perpendicular to the cutting direction. These son can be advantageously replaced by two blades, with equivalent cutting technical effects.

Advantageously, the two son are stretched horizontally on the same frame, formed of two substantially vertical uprights each disposed on either side of the support plate, and movable in horizontal translation by means of a motorization system.

Preferably, the trays comprise a plurality of perforations allowing the drying of the green products they carry, by pulsing hot air through said perforations.

In addition, the means for transferring the rack carrying the green product in the direction of a drying station consist of a conveyor system (for example belts, belts, rollers) intended to transfer by sliding the rack and the green product that it relates to a conveyor disposed between the downstream end of the support plate, and the drying station.

Finally, the transfer means of an empty rack on the support plate consist of a conveying system disposed at the upstream end of said support plate, and intended to perform the transfer by sliding of an empty rack on said plate.

• Figure 1 en est une vue de profil en coupe partielle, montrant les vis de malaxage de la terre, la vis d'extrusion, la filière, le plateau support de claies, ainsi que les convoyeurs de claies vides et chargées ;
• Figure 2 est une vue agrandie en perspective d'un plateau support de claies du dispositif de l'invention ;
• Figures 3 à 7 sont des vues de profil de la filière et du plateau support de claies dans différentes phases de la fabrication d'un produit vert ;
• Figure 8 est une vue de dessus d'une claie perforée, chargée avec un produit vert ;
• Figure 9 est une vue de profil selon IX/IX de figure 8.

In any case, the invention will be better understood with the aid of the detailed description which follows, and with reference to the appended schematic drawing showing by way of nonlimiting example an embodiment of a device for manufacturing elements. terracotta according to the invention.

• Figure 1 is a side view in partial section showing the kneading screws of the earth, the extrusion screw, the die, the shelf support tray, as well as empty and loaded trays conveyors;
• Figure 2 is an enlarged perspective view of a tray support racks of the device of the invention;
• Figures 3 to 7 are side views of the die and tray support trays in different phases of the manufacture of a green product;
• Figure 8 is a top view of a perforated screen, loaded with a green product;
• Figure 9 is a profile view according to IX / IX of Figure 8.

The device 1 according to the invention, as shown in Figure 1 allows the manufacture of terracotta elements, by vertical extrusion of clay, and then drying extruded green products.

• une trémie 2 et une vis 3 d'alimentation en terre d'une filière 4 pour l'extrusion verticale d'un élément en terre 5,
• un plateau 6 mobile selon un axe vertical et disposé en regard de la filière 4, formant support pour une claie 7 de transport d'un produit vert 8, la mobilité du plateau support 6 étant rendu possible par un vérin 9 situé sous ledit plateau,
• des moyens de découpe de l'élément extrudé 5 pour former le produit vert 8,
• des moyens de transfert de la claie 7 portant le produit vert 8 en direction d'un poste de séchage (non illustré au dessin) et des moyens de transfert d'une claie vide sur le plateau support 6.

It consists of the following elements:

• a hopper 2 and a feed screw 3 of a die 4 for the vertical extrusion of an earth element 5,
• a plate 6 movable along a vertical axis and arranged facing the die 4, forming a support for a rack 7 for transporting a green product 8, the mobility of the support plate 6 being made possible by a jack 9 located under said plate,
• means for cutting the extruded element 5 to form the green product 8,
• means for transferring the rack 7 carrying the green product 8 to a drying station (not shown in the drawing) and means for transferring an empty rack to the support plate 6.

As shown in FIGS. 1 and 2 of the appended schematic drawing, the means for transferring the rack 7 carrying the green product 8 in the direction of a drying station consist of a plurality of rollers 10 of the support plate 6, rotating in rotation to effect the sliding transfer of the rack 7 and the green product 8 that it carries on a conveyor 11 disposed between the downstream end of said support plate, and the drying station.

The transfer means of an empty rack 7 on the support plate 6 consist of a conveying system 12 disposed at the upstream end of said support plate, and intended to effect the transfer by sliding of an empty rack 7 on said plate 6 .

According to the invention, the cutting means comprise two son 13 superimposed vertically at a distance from one another, equivalent to the length of the green product to obtain, the son 13 being each stretched horizontally on a frame secured to the support plate 6, so as to accompany each descent of the extruded material during the cutting phase.

More precisely, as is clearly visible in FIG. 2, the two wires 13 are stretched horizontally on the same frame, formed of two substantially vertical uprights 14 each disposed on either side of the support plate 6, and movable in horizontal translation. thanks to a cylinder 15.

As illustrated in FIGS. 8 and 9, each rack 7 comprises a plurality of perforations 16 allowing the drying of the green product 8 it carries, by hot air pulsation - represented by an arrow - through said perforations 16.

Figures 3 to 7 show the different main steps of the method of manufacturing terracotta elements having parallel cells 17, according to the invention.

As shown in FIG. 3, the material is first extruded vertically through the die 4 so as to form an extruded element 5.

Then, as illustrated in FIG. 4, the vertical translation upwards of the support plate 6 is automatically controlled automatically at the same time as the earth element 5 is extruded until the free end of said extruded element against the rack 7 carried by the horizontal support plate 6, as shown in Figure 5.

Then, simultaneously with the extrusion of the piece of earth 5 which continues, the descent of the support plate 6 is performed, as well as the simultaneous cutting of said earth element to form a green product 8, as shown in FIG.

The cutting is performed by horizontal translation of the two cutting son 13 described above, at the same time as the horizontal plate 6 is moved up and down at the extrusion rate of the clay material.

As illustrated in FIGS. 6 and 7, the distance between the two cuts - that is to say the distance separating the two cutting wires 13 - is equal to the length of the green product 8 to be obtained, the cutout located on the side of the free end of the extruded material leaving between itself and said free end, a sole 18 intended to serve to support the green product 8 during the handling and drying phases.

As illustrated in FIG. 7, at the end of the cutting phase of the green product, the complete descent of the support plate is controlled at a speed greater than the extrusion speed, so that the green product 8 cut is detaches from the rest of the extruded earth element 5.

The cutting son 13 are optionally returned to their initial position, and the transfer of the rack 7 carrying the green product 8 on the downstream conveyor 11, which will transport this green product to a drying station. At the same time, an empty rack is transferred onto the support plate 6 from the upstream conveyor 12.

After complete cutting of a green product, it is dried by hot air through the holes of the rack, as shown by the arrows in FIG. 9.

It goes without saying that the invention is not limited to the embodiment described above as an example but that it encompasses all variants.

Thus, it will be possible in particular to provide an adjustment of the size and the arrangement of the perforations of the trays to adapt the speed and flow rate of the hot air flow to the different types of products to be dried.

Similarly, in some cases, to increase the productivity of the machine, extrusion can be provided with multiple dies, arranged side by side in the transverse direction of the machine, and / or in the longitudinal direction thereof, the number of trays then being multiplied accordingly so that a rack is arranged opposite each die, and the extrusion process and cutting is simultaneous, for all channels.

These individual trays can be replaced by a single rack that can receive all products from multiple channels.

Claims (7)

A method of manufacturing terracotta elements having parallel cells (17), comprising: (i) vertically extruding the material continuously through a die (4) to form an extruded member (5), (ii) bringing the extremity of the extruded element into abutment against a rack (7) carried by a plate (6) forming a horizontal support, (iii) transversely cutting the extruded member (5) to form a green product (8), at the same time that the horizontal platen (6) is moved up and down at the extrusion speed of the material, characterized in that it consists in making two transverse cuts of the extruded element (5) to form the green product (8), the distance between the two cuts being equal to the length of the green product to be obtained, the cutout located in the side of the free end of the extruded material leaving between itself and said free end, a sole (18) intended to support the product during the handling and drying phases. Process according to Claim 1, characterized in that after complete cutting of a green product (8), it consists in drying the latter by hot air injection through the orifices (16) of the rack (7). Device (1) for the manufacture of terracotta elements, according to the method of claims 1 or 2, comprising: a hopper (2) and a screw (3) for supplying a bushing (4) with earth for the vertical extrusion of an earth element (5), - A plate (6) movable along a vertical axis and arranged opposite the die (4) forming a support for a rack (7) for transporting a green product (8), means (13) for cutting the extruded element (5) to form the green product (8), means (11) for transferring the rack (7) carrying the green product (8) in the direction of a drying station and means (12) for transferring an empty rack to the support plate (6), characterized in that the cutting means comprise two son (13) superimposed vertically at a distance from one another, equivalent to the length of the green product (8) to obtain, the son being each stretched horizontally on a solidarity frame the support plate (6), so as to accompany each descent of the extruded material (5) during the cutting phase. Device (1) according to claim 3, characterized in that the two son (13) are stretched horizontally on the same frame, formed of two uprights (14) substantially vertical each disposed on either side of the support plate (6) and movable in horizontal translation by means of a jack (15). Device (1) according to claims 3 or 4, characterized in that the trays (7) comprise a plurality of perforations (16) for drying the green products (8) they carry, by hot air impulse through said perforations (16). Device (1) according to claims 3 to 5, characterized in that the means for transferring the rack (7) carrying the green product (8) towards a drying station consist of a conveying system (10) intended slidably transferring the screen (7) and the green product (8) onto a conveyor (11) disposed between the downstream end of the support plate and the drying station. Device (1) according to claims 3 to 6, characterized in that the means for transferring an empty rack (7) onto the support plate (6) consist of a conveyor (12) of empty racks disposed at the upstream end said support plate (6), and a conveying system (10) for effecting the sliding transfer of an empty shelf to said tray.

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