EP1227920B1 - Method for producing bricks or floor tiles from clay - Google Patents

Abstract

The invention relates to a device and to a method for producing bricks or floor tiles from clay. A single-layer structure (2', 3) or a first (2') and a second (3) fabric layer is placed and fastened in a mold that receives the clay. The second fabric layer (3) has a lesser porosity or mesh width than the first fabric layer (2'). The mold is provided with at least one opening in its bottom to which a compressed-air generator is connected. Once the clay is filled in the mold, pressure is exerted by means of a pressure ram in order to remove from the clay any water and air that might be trapped therein.

Description

The invention relates to a method for the production of clay bricks or floor slabs, which can be used in particular for the restoration of buildings and a particularly aesthetic design in public and private buildings, with a reference to historical purely handmade prototypes is possible.

In the recent past, tile and floor tile manufacturing has become more and more industrialized and the potential automation aspect has been increasingly taken into account to ensure cost effective mass production. In this way, readily produced products can be produced in large numbers, however, look almost identical and where due to the grinding and mixing units used a homogenization of the clay mass destroys the special mineralogical structure, and so the individuality of each clay occurrence used for the Overall impression of the finished product is eliminated.

In the conventional industrial brick pressing process costly tools that are designed according to the particular form used. However, this is justified from a commercial point of view only in relatively large quantities.

For the individual design, as z. As in the preservation of monuments, the restoration of old churches or other buildings is desired, the required quantities are in a much lower range, so that a corresponding procedure leads to correspondingly increased costs for the individual product.

Disregarding the, as already mentioned, when mixing or grinding already destroyed mineralogical structure of the Ausgangsstones are usually to influence the overall aesthetic appearance dyes or others added mineralogical additives, but with which the natural impression of the clay as starting material can not be achieved again.

Even the original artisanal approach, as it was used several centuries ago, can not be easily revived in the form, since corresponding experience and craft knowledge has been lost in the meantime and also, in particular, the required workload is too large, so that a economical production of such tiles or floor tiles is not achievable even with today's quality requirements.

From AU-B-479 684 a method and an apparatus for producing concrete panels is known in which a slurry of cementitious material is introduced between two molds and an extraction is provided in at least one of the casting bowls to remove moisture from the mushy material to be able to.

Furthermore, from BE-A-865 053 and FR-A-1 036 962 a device for the production of bricks or floor panels made of clay with a molded body and a press die is known in which a the bottom surface of the molded body overlapping, at least single-layered structure is inserted in the molded body and is secured in this and beyond at least one opening for supplying compressed air between the molded body and the structure is provided.

It is therefore an object of the invention to suggest ways in which tiles or floor tiles can be made relatively easily and inexpensively from clay, the mineralogical structure of the clay used remaining aesthetically effective in the finished products.

According to the invention, this object is achieved with the features of claim 1 for a method. Advantageous embodiments and developments of the invention will become apparent from the dependent claims.

According to the invention, the procedure is that processed with relatively coarse agents kneaded and correspondingly supple clay, which also a conventional excavator can be used, is further processed without homogenization of the mineralogical structure of the clay occurs.

The thus prepared clay may optionally be processed in a relatively large-sized form to a leaf, when the clay is inserted into the mold and pressed accordingly, and after removing the mold wall of the resulting leaves stick is cut by means of a tensioned wire so that it as a precursor pre-portioned and / or pre-formatted.

The clay prepared in this way can then be further processed by means of a device according to the invention, which consists essentially of a shaped body and a pressing die.

In this case, the prepared clay is inserted into the molding and applied by means of the press ram with a compressive force, so that water and air inclusions are removed from the clay. This can be achieved by a relative movement between the press die and the shaped body, that is to say even with a rigid press die and movement of the shaped body in the direction of the press die be achieved.

In the interior of the molded body, an at least single-layer flexible structure is arranged and secured thereto. The structure should at least cover the bottom surface of the molding. The inner side walls may also be covered, but other flexible materials can be used for this purpose. The material used for the sidewall cover may or may not necessarily retain the clay particles.

The material can be a one-piece blank. But it can also be used for each side wall a separate blank of such material.

In the structure, the surface of the structure pointing in the direction of the clay may have a smaller porosity or mesh size than the remaining part of the structure.

The material of the structure and its connection structure is chosen so that mineral clay particles retained and on the other hand the demoulding can be facilitated.

For demolding, at least one opening is formed in the molded body, preferably in or on the bottom, which is connected to a compressed air generator, wherein a valve is opened for demolding and compressed air is passed through the opening between the molding wall and structure to form an air cushion.

With the compressed air can optionally in the building material the remaining water is pressed back and formed between the clay and structure a mixed film, which further facilitates the demolding.

Before demoulding, the molded body can be pivoted through 180 ° and only then can the compressed air be passed through the one or more openings to facilitate demolding.

The demolded blank may then be fired in conventional manner, optionally after predrying in air, wherein it can be prepared in various shapes and dimensions according to the molding used to meet the respective requirements.

Advantageously, the substantially flat structure is additionally fixed to the bottom of the molded body, which should be used for this reasonably clamp-shaped fixing elements. The fixing elements are favorably arranged in a grid corresponding to the tile or floor tile formats, in particular in the production of a plurality of tiles in a shaped body, ie in edge regions of the individual tiles or slabs.

If a molded body is used, the bottom of which is made of wood, conventional clips can be used for this, which are then pressed into the wood.

Layer-glued wood has proven to be particularly suitable for use as the bottom of a shaped article and here in particular the use of layer-glued birch veneer as suitable.

The outer edges of the molding can then be formed, for example, with beech wood, which can be easily bolted to the ground.

However, the edges of the mold can also be readily formed from metal profiles.

The structure, which should also have a certain storage capacity for water, is guided at least up to the upper edge of the molding. However, it should overlap the upper edge of the molding and be clamped there. The clamping can be done either by appropriate profiling in a metal profile or by means of sheets, which can also be fastened at the top by a screw, it being advantageous to use cranked sheets that secure a higher spring tension for fastening the structure when screwing.

During the pressing process of the clay used in the molding, the water escaping from the clay can partially escape through the joints of such a molding.

Of course, a metallic molded body can also be used, wherein in the case of an otherwise closed molded body (casting, welded construction) at least one opening in the molded body should be formed, through which the leaked water from the clay can escape. Such an opening is usually not required in a metal mold assembled from individual parts, since the water can also escape via joints here.

For the processing of prepared accordingly, As far as possible anhydrous clay should be avoided in a metallic clay body on openings or open joints for the water outlet.

A metal moldings can be made of welded metal profiles with a bottom part. On the upper faces of these metal profiles strips or other metal profiles can be attached to the clamping fixation of the structure with screws.

If a device according to the invention is used in which the porous structure only covers the bottom of the shaped body, the structure can be fastened in a clamping manner in the joints between the bottom and side walls.

In such an embodiment, to facilitate demoulding of the pressed bricks or slabs prior to filling with clay, an application of conventional release agents may be made to the unoccupied free inner surfaces of the sidewalls.

However, the use of such release agents can be dispensed with if at least these surfaces are coated with an anti-adhesion layer, e.g. are coated with PTFE or at least partially in electrically conductive sidewall material (metal) an electrical voltage, low voltage is applied briefly before demolding.

Various fibers can be used as the structural material, but at least the surface in contact with the clay should reach a mesh size or porosity of less than 0.08 mm, preferably 0.015 mm, in order to ensure a sufficient filtering effect. The mesh size or porosity should be optionally, taking into account the different starting clay masses are chosen so that a substantial proportion of the clay particles is retained.

It can be used in addition to natural fibers and other different synthetic fibers that form a fabric, knitted fabric, a knitted fabric, a nonwoven, needle felt or felt.

The individual fibers, loops or loops within the structure may be packed in different densities or have different sizes, in each case the smallest distances, mesh or pore widths on the surfaces of the structure, which are in contact with the clay during pressing, should be available.

If needle felt is used as the structural material, the porosity need not be correspondingly smaller in order to retain the mineral clay particles, since its properties in this respect can also be achieved in this way.

The structural material can also be a foamed plastic, preferably foamed polyurethane.

In this case, a one-piece structure made of foamed plastic can be inserted and fixed in the molded body. But it can also be used five individual parts, while a part on the floor and four parts are each arranged on the side walls.

But it can also be a composite of at least two different materials are used. These materials are then directly connected to each other surface. This can be achieved by mechanical clamping, hooking or punctiform bonding or welding.

Such formed structures can not only retain mineral clay particles, but store additional water and secure a flow resistance of the structure for the injected through the opening compressed air to form air cushions.

In certain cases, the single-layer structure may also be underlaid as a molded body, at least in the area of the floor. For this purpose, a flexible, porous material can be used, which, if anything, can be connected to the structure only at the outer edges.

The material can be used in one or more layers.

It can have the same porosity or mesh size as the structure.

As a result, the mineral clay particles can be retained even more effectively and remain almost completely contained in the Austangstonmasse from which the tiles or plates are made.

The bricks or slabs have a flat, smooth surface and it can be dispensed with a mechanical post-processing, especially since no seams and possibly no fixing elements in the bottom area are available.

It is also beneficial to form the structure so that it is elastically extensible. This can be achieved with elastic fibers, twine or yarns and / or a corresponding connection structure of such materials. The extensibility is particularly advantageous during removal from the mold with the compressed air.

There is also the possibility of occupying the press die used with the structural material, which comes into contact with the sound during the pressing process.

The invention can be used both manually, as well as mechanized, up to the fully automatic production of bricks or floor panels.

The finished products have a typical aesthetic impression of the particular tone used.

Inside the molded body, two layers of fabric can be arranged and attached to this. In this case, the second fabric layer pointing in the direction of the clay has a smaller porosity or mesh width than a first fabric layer which bears against the inner wall of the molded article.

In this case, the second fabric layer with the smaller porosity or mesh size once the task of retaining mineral clay particles and on the other hand, it has an essential function in Entformvorgang.

For removal from the mold, in turn, at least one opening is formed in the molded body through its bottom, which can be connected to a compressed air generator, a valve being opened for removal from the mold is and compressed air is passed through the opening under the two layers of fabric in the molding. This makes it possible to press an air-water mixture through the fabric layers, so that forms a corresponding film under the present blank, which significantly facilitates demolding. With the compressed air, the water absorbed in advance in the first fabric layer is pressed through the second fabric layer to form this mixed film. At the same time, air cushions form below the second fabric layer.

Advantageously, the second fabric layer is sewn onto the first fabric layer, wherein the seams can be arranged at predetermined distances from each other. If seams are formed at an angle of 90 ° to each other, a cushion-like structure can be produced, which still has a particularly advantageous effect during demolding. Due to the supplied compressed air in each case between the seams air cushion below the second fabric layer, because of their greater flow resistance, which correspond in size to the seam structure, so that the distance between the individual seams to each other for the size of the formed air cushion has a significant influence, wherein a distance of seam to seam of 20 mm to 100 mm has proven to be favorable.

Advantageously, the two fabric layers are additionally fixed to the bottom of the molded body, wherein for this purpose clamp-shaped fixing elements should be used, which then embrace a seam, so that even with compressed air supply the seam area is lifted only slightly from the bottom of the molding.

If a molded body is used, the bottom of which is made of wood, conventional clips can be used for this, which are then pressed into the wood.

The first fabric layer, which should also have a certain absorption capacity for water and at least be guided to the upper edge of the molding. The second fabric layer overlaps the upper edge of the molding and is clamped there. The clamping can be done either by appropriate profiling in a metal profile or by means of metal sheets, which can also be fastened by a screw at the top, it being advantageous to use cranked plates, which when screwing a higher spring tension for fastening the second fabric layer to back up.

Different fiber materials can be used for the two fabric layers, but a material should be used for the finer second fabric layer, which reaches a mesh size or porosity below 0.08 mm, preferably at 0.015 mm, by means of a suitable weaving or knitting process to ensure a sufficient filtering effect. If appropriate, the mesh size or porosity, taking into account the different starting clay masses, should be chosen such that a substantial proportion of the clay particles is retained.

In addition to natural fibers, other different synthetic fibers can be used for the first fabric layer.

There is also the possibility of occupying the press die used with at least one fabric layer, which comes in contact with the sound during the pressing process. But it can also, as in the molding, two corresponding fabric layers are used, in which case the second fabric layer may have a smaller porosity or mesh size.

The invention can be used both manually, as well as mechanized, up to the fully automatic production of bricks or floor panels.

The finished products have a typical aesthetic impression of the particular tone used.

The invention will be described below by way of example.

Figur 1

einen Teilschnitt durch einen Formkörper mit einem einlagigen Gebilde eines Beispiels für eine erfindungsgemäße Vorrichtung und

Figur 2

einen Teilschnitt eines Formkörpers mit zwei Gewebelagen.

Showing:

FIG. 1

a partial section through a molded body with a single-layer structure of an example of a device according to the invention and

FIG. 2

a partial section of a molded article with two fabric layers.

In the apparatus shown in Figure 1, a bottom 1 ', which consists of layer-glued birch veneer, used, on the mold edge 7 can be fixed by means of screws 8. The mold edge 7 is formed in this example of a plurality of appropriately sized and arranged Buchenkatt wood, with which the shape and size of the tile produced or the floorboard can be specified.

In the interior of the molded body 1, the single-layer, porous, flexible structure 2 is inserted and fixed there several times. For fastening serve on the mold edge 7 with screws 8 fixed sheets 4, with which the structure 2 can be clamped. The plates 4 are formed cranked to achieve a higher spring tension for the support of the structure 2.

The structure 2 can then be additionally fastened with clamp-shaped fixing elements 5 on the bottom 1 'of the molded body 1, so that when compressed air through the opening, not shown here, the corresponding fixed parts of the structure 2 at least in the vicinity of the surface of the bottom 1' be kept and in the remaining, not so held areas in the compressed air supply air cushion can be formed below the structure 2.

For the structure 2 may suitably find a material use, which has a certain water absorption capacity. This is e.g. when using conventional needle felt. However, it is also possible to use a composite with a technical filter fabric, with the various materials being connected to one another directly on a flat surface.

The structure 2 should consist of a material and a composite structure, with which a sufficiently high flow resistance for the compressed air is achieved, so that the air cushion can be formed to facilitate the demoulding of the tile or floor slab blank.

In the example shown in Figure 2 is also a floor 1 ', which consists of layer-glued birch veneer used, on which the mold edge 7 can be fixed by means of screws 8. the mold edge 7 is formed in this example of several appropriately sized and arranged Buchenkatt wood, with which the shape and size of the tile or the floor panel can be specified.

In the interior of the molded body 1, a first fabric layer 2 'and a second fabric layer 3 are inserted and are fixed there several times. For the attachment of the two fabric layers 2 'and 3 are used on the mold edge 7 with screws 8 fixed sheets 4, with which the second fabric layer 3 can be clamped. The sheets 4 are formed cranked to achieve a higher spring tension for the maintenance of the fabric layer 3.

The first fabric layer 2 'and the second fabric layer 3 are sewn together, wherein the seams 6 are preferably arranged at regular intervals.

The correspondingly interconnected fabric layers 2 'and 3 can then be additionally fastened with clamp-shaped fixing elements 5 on the bottom 1' of the molding, wherein the fixing elements 5 favorably embrace a seam, so that upon supply of compressed air, through the opening, not shown here, the corresponding Area of the two fabric layers 2 'and 3 at least in the vicinity of the surface of the bottom 1' is held and in the remaining, not so held areas, compressed air supply air cushion can be formed below the second fabric layer 3.

For the first fabric layer 2 'can be conveniently used a material that has a certain water absorption capacity. This is e.g. when using conventional needle felt. For the first fabric layer 2 'but also a technical filter fabric, which is available under the trade name "Tetex PP-120 / DLW", can be used.

For the second fabric layer 3, which is substantially finely meshed or finer pored than the first fabric layer 2 ', for example, a technical filter fabric, which is commercially available under the trade name "Nyboldt PA 15/10", be used, which has a mesh size of 0.015 mm Has. This ensures that a sufficient filtering effect can be achieved by the second fabric layer 3, to prevent mineral clay particles from escaping during the pressing process, and at the same time a sufficiently high flow resistance for the compressed air is achieved, so that the air cushion to facilitate the removal of the Brick or floor slab blanks can be formed.

With the appropriately trained device loads up to 500 tons can act during the pressing process, without damage occurs and safely in the sound contained air or water can be expelled.

With the correspondingly designed devices, loads of up to 500 t can act during the pressing process, without damage occurring and air or water safely contained in the clay being expelled.

Claims (11)

1. Process for the production of bricks or floor tiles from clay, wherein mechanically kneaded and softened, preformatted and/or portioned clay is placed in a mould(1) and inclusions of water and air are removed from the clay by the application of pressure with a pressure ram and the shape of the brick or the floor tile is created;
   wherein the emerging water is at least partially absorbed in a first fabric layer (2) and clay particles are retained by means of a second fabric layer (3) or water is absorbed in and clay particles retained in a single-layer structure (2); after the removal of the pressure ram, compressed air is introduced through the opening(s) in the base (1') of the mould (1), so that a water-air mixture flows through the structure (2) or the second fabric layer (3) and air cushions are formed under the structure (2) of the second fabric layer (3) and then the prepared brick or the floor tile is removed from the mould before the firing process.
2. Process according to Claim 1, characterized in that the application of pressure for the removal of water and air inclusions from the clay is effected by a relative movement between mould (1) and pressure ram.
3. Process according to Claim 1 or 2, characterized in that the mould (1) is swung through 180° before the demoulding and then compressed air is introduced through the opening(s) in the base (1').
4. Process according to one of Claims 1 to 3, characterized in that kneaded and softened clay is pressed into a mould and the lamellar mass thus obtained after removal of the mould is cut into preformatted and/or portioned pieces, which are used in the mould(1).
5. Process according to one of Claims 1 to 4, characterized in that a fabric, textile, knitted fabric, nonwoven, felt material, needled felt or foamed plastic is used as the structure (2), wherein the structure (2) is elastically extensible and formed of at least two different materials, directly joined flat to one another.
6. Process according to one of Claims 1 to 5, characterized in that an enlarged pore size or mesh width of the structure (2) is used on the side facing the surface of the mould(1), while the pore size or mesh width of the structure (2) on the surface coming into contact with clay is < 0.08 mm.
7. Process according to one of the foregoing claims, characterized in that the whole inner surface of the moulding body (1) is covered by the structure (2), and/or that the inner side walls of the mould(1) is covered with a flexible material different from the structure material, and/or that the structure (2) is underlaid at least in the base region of the mould(1) with a flexible porous material, wherein structure (2) and material in the base region of the mould (1) are not bound, and/or that at least the surfaces of the inner side walls of the mould (1) are coated with PTFE and/or that the pressure ram is coated with a structure material.
8. Process according to one of the foregoing claims, characterized in that a first fabric layer (2') and a second fabric layer (3) are inlaid and fixed in the mould (1) accommodating the clay, wherein the second fabric layer (3) has a lower porosity or mesh width than the first fabric layer (2') and the fabric layers (2') and (3) each completely cover the inner surface of the mould (1), and that in the mould (1) at least one opening through the base (1') thereof is provided, which is connected to a compressed air source, wherein the second fabric layer (3) is for example sewn onto the first fabric layer (2') and/or wherein the seams (6) are arranged at preset intervals one from another and are oriented at an angle of 90° to one another.
9. Process according to Claim 8, characterized in that the first and second fabric layers (2') and (3) are held on the base (1') of the mould (1) with clamp-shaped fixing elements (5) and one seam (6) is encompassed by each fixing element (5) and/or that the first fabric layer (2') is continued at least up to the upper edge of the moulding body (1), wherein the second fabric layer overlaps the upper edge of the mould (1) and is clamped there.
10. Process according to one of the foregoing claims, characterized in that at least the base (1') of the mould (1) is made of wood.
11. Process according to one of the foregoing claims, characterized in that the pore size or mesh width of the second fabric layer (3) is selected to be < 0.08 mm, wherein for example the pressure ram is also coated with a second fabric layer, the pore size or mesh width whereof is smaller than that of the first fabric layer.

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