EP1260334A1 - Process and device for producing building components - Google Patents

Abstract

The procedure consists of filling a multi-compartment mould (14) with a mixture of plaster, sand and water, and compressing the mixture slowly to compact it and remove surplus water and air, reducing its volume to a minimum level. The pressure applied at a low level for a long course, followed by a higher lever for a short course, reaching a maximum of about 10 MPa. The mould is removed simultaneously from all the blocks, which measure about 25 x 50 x 10 cm each and are then allowed to set on their own.

Description

The present invention relates to a method and a device for manufacturing construction elements, in particular for interior walls of buildings, from a mixture of plaster, a filler such as sand and water.

It is already known, for example from EP-A-0619773, to make building blocks from a mixture of plaster, a filler such as sand and of water, by pressure molding of this mixture for a sufficient time to perform a pressurized hydration of plaster and thus obtain densification of its crystal lattice.

The building blocks thus obtained have excellent, comparable mechanical properties to those of building stones they can be used in construction at the exit of the molds without prior drying, and they have a very large dimensional precision that allows them to be mounted on top of each other without joints.

In this known process, the mixture of plaster, sand and water is compressed slowly and left under pressure in the mold during the plaster setting, this duration is generally several minutes, then the mold is opened and the block is removed from the mold for be stored or used in construction. It is necessary for demolding to exert a push relatively strong on the block, due to the relatively high pressure applied by the block on the walls of the mold, and which results from expansion of the plaster inside the mold. he sometimes happens if we leave the block too long in the mold, that the expansion of the plaster is finished and it is impossible to unmold the block, if a hydraulic cylinder is not available powerful enough. For these reasons, we are leads either to demould the blocks for example at two thirds of the expansion of the plaster, which requires know the duration of the maximum expansion of the plaster with sufficient precision, either to equip the very powerful cylinder making machine, so relatively very expensive.

By the way, taking the plaster inside of the mold results in immobilization of the mold for a relatively long time, which requires having a large number of molds or support relatively high production rates low.

The object of the present invention is in particular to provide a simple, satisfactory solution, effective and inexpensive to these problems, in particularly in the case of the manufacture of elements of construction intended to be used for inside a building.

To this end, it proposes a method of manufacture of construction elements, such as example that interior wall panels of buildings, from a mixture of plaster, a load such as sand and water, the amount of water in the mixture being slightly higher than that necessary for the hydration of plaster, this process being characterized in that it consists in compressing this mix in a multi-compartment mold for tamp it down and to evacuate excess water and air contained in the mixture and reduce its volume substantially down to a minimum value and then to simultaneously unmolding the elements by translation of the mold relative to the elements kept stationary and allow the plaster to take hold in elements outside the mold.

• on peut démouler les éléments de construction dès que leur compression dans le moule leur a donné une cohésion interne suffisante, c'est-à-dire après un temps de l'ordre de 30 secondes au maximum,
• on peut mouler et démouler simultanément plusieurs éléments de construction, ce qui augmente la cadence de fabrication,
• le démoulage des éléments s'effectue avant la prise du plâtre, donc pratiquement sans expansion volumique du plâtre et peut être réalisé sans effort avec un vérin hydraulique relativement peu puissant,
• la compression du mélange dans le moule permet de conférer aux éléments de construction des caractéristiques mécaniques relativement élevées, très largement supérieures aux minima imposés, et une bonne précision dimensionnelle.

The method according to the invention has a certain number of advantages compared to the known technique:

• the construction elements can be removed from the mold as soon as their compression in the mold has given them sufficient internal cohesion, that is to say after a time of the order of 30 seconds at most,
• several construction elements can be molded and demolded simultaneously, which increases the production rate,
• the elements are removed from the mold before setting the plaster, therefore practically without volume expansion of the plaster and can be carried out effortlessly with a relatively weak hydraulic cylinder,
• the compression of the mixture in the mold makes it possible to confer on the construction elements relatively high mechanical characteristics, very much greater than the minima imposed, and good dimensional accuracy.

According to another characteristic of the process according to the invention, the maximum final pressure applied to the mixing in the mold is of the order of 10 MPA.

The construction elements thus produced have a compressive strength of at least 15 Mpa and which is typically from 25 to 30 Mpa approximately.

We can use these elements to make load-bearing partitions.

Advantageously, this method also consists in use delayed or relatively set plaster slowly, and mix it evenly and progressive to the aforementioned quantity of water.

Thanks to the slow or delayed setting of this plaster, you can mix without having to do this very quickly, allowing more mixing uniformly plaster, sand and water.

Generally, the amount of charge in the the above mixture can vary between 30 and 80% approximately, in weight.

Advantageously, the mixture compressed in the mold contains hydrophobic agents such as silicones for example.

Typically, building elements thus produced are planar elements for walls interiors, for example having dimensions of 25cmx 50cmx 10cm, but we can intended to achieve by carrying out the process according to the invention of building elements all having desired shapes and dimensions.

The invention also provides a device for performing this process, including a mold rigid and non-deformable side walls and upper and lower openings closed by trays movable in translation inside the mold, means for compressing the mixture in the mold and release means for the elements of construction, this device being characterized in that that the mold includes internal partitions delimiting molding compartments of said elements and in that the mold release means include support means on the faces elements in the compartments of the mold and mold translation means parallel to said elements.

This device makes it possible to mold simultaneously and easily demould a plurality of elements, with one mold.

According to another characteristic of this device, the compression means include means for moving the upper plate and / or the lower tray inside parts of the mold which have no internal partitions.

These compression means can be independent of the support means used for the mold release, or understand the same means as these support means.

• la figure 1 est une vue schématique en coupe axiale d'un dispositif selon l'invention, le moule étant représenté ouvert ;
• la figure 2 est une vue correspondant à la figure 1, mais représente le moule fermé ;
• la figure 3 est une vue schématique de dessus du moule ;
• la figure 4 est une vue semblable aux figures 1 et 2, mais représente le dispositif au cours du démoulage des éléments de construction.

The invention will be better understood and other characteristics, details and advantages thereof will appear more clearly on reading the description which follows, given by way of example with reference to the appended drawings in which:

• Figure 1 is a schematic view in axial section of a device according to the invention, the mold being shown open;
• Figure 2 is a view corresponding to Figure 1, but shows the closed mold;
• Figure 3 is a schematic top view of the mold;
• Figure 4 is a view similar to Figures 1 and 2, but shows the device during the demolding of the construction elements.

The manufacturing device according to the invention is intended in particular to be used with a hydraulic press, comprising at least one cylinder hydraulic and preferably two hydraulic cylinders axially aligned.

In the example shown in Figures 1, 2 and 3, the press includes an upper hydraulic cylinder 10 and a lower hydraulic actuator 12 with action vertical, which are axially aligned and between which are mounted the mold for manufacturing building elements.

This mold 14 is of general shape rectangular and includes walls side 16 which are rigid and undeformable. His upper and lower ends 18, 20 respectively, are open and receive upper 22 and lower 24 closing plates substantially horizontal which are movable in vertical translation inside the mold 14 with a small clearance compared to the side walls of the mold.

The internal space of the mold 14 is divided into one plurality of identical compartments 26 by internal partitions 28 which extend vertically between the side walls 16 of the mold and which are fixedly mounted on these walls. Internal partitions 28 have a height less than that of the mold 14 and terminate at a distance from the open ends 18, 20 of the mold, forming stops which limit the races of the plates 22 and 24 inside the mold.

The upper plate 22 can be fixed or hung on a plate 30 movable in translation vertical by the upper cylinder 10, and likewise the lower plate 24 is fixed or hung on a plate 32 movable in vertical translation by the lower cylinder 16.

As shown, the lower part of the mold 14 which extends under the internal partitions 28 can be formed by an independent tubular element 34 of the upper part of the mold or maybe, alternatively in one piece with this part higher.

initialement, l'extrémité inférieure 20 du moule est fermée par le plateau 24 qui est engagé sur une très faible hauteur, par exemple un centimètre environ, à l'intérieur de la partie inférieure 34 du moule, et le plateau supérieur 22 est retiré ou écarté de l'ouverture supérieure du moule. Un mélange de plâtre, d'une charge telle que du sable et d'eau est ensuite versé à l'intérieur du moule 14, pour remplir les compartiments 26 et recouvrir les bords supérieurs des cloisons 28.

The method of manufacturing construction elements according to the invention by means of this device is as follows:

initially, the lower end 20 of the mold is closed by the plate 24 which is engaged over a very low height, for example about one centimeter, inside the lower part 34 of the mold, and the upper plate 22 is removed or away from the upper opening of the mold. A mixture of plaster, of a filler such as sand and water, is then poured inside the mold 14, to fill the compartments 26 and cover the upper edges of the partitions 28.

This mixture comprises from 30 to 80% by weight about charge and about 70 to 20% by weight of plaster, the amount of water being slightly a few percent higher, for example, than that which is necessary for a maximum density of the mixture (optimum Proctor). Depending of grain sizes of the filler and plaster, the quantity of water can vary between 1.5 and 1.9 liters approximately in the case of a mixture comprising approximately 6 kilos of sand and 4 kilos of plaster.

We can advantageously use a plaster delayed or slow setting to allow time sufficient to mix sand, plaster and water substantially homogeneously before the plaster begins taking.

A small amount can be added to the mixture hydrophobic products, such as silicones by example, in a proportion of about 1 to 5 for thousand of the weight of water used.

The homogeneous mixture of plaster, sand and water is difficult if not impossible to achieve if we just pour a desired amount of water on a mixture of plaster and sand. Either spray the water on the plaster and sand mixture when this mixture falls into the mold, either spray water on a mixture of plaster and sand in a mixer designed for this purpose, as described for example in WO 00/30819. Otherwise, plaster, sand and water form a compact and sticky block in which the water is poorly distributed and that no one cannot mold properly even when compressing strongly.

When an amount of the mixture corresponding to internal volume of the mold was poured into the mold, we cup and slowly compress this mixture in the mold to obtain maximum density resulting a discharge of excess water and air contained in the mixture, which can escape through the clearances between the plates 22 and 24 and the walls side of the mold, these games being small, around a tenth of a millimeter or less.

For this compaction and compression, we can, depending on the mold filling conditions 14, or move only the lower plate 24 upwards until it stops at the edges lower partitions 28, either move simultaneously the plates 22 and 24 towards each other inside the mold.

• suppression des plans de clivage qui pourraient résulter de l'application d'une pression unidirectionnelle,
• bon mouillage de la totalité de la surface des grains de la charge,
• déplacement de ces grains et organisation de leur disposition pour une compacité maximale.

When the elements to be manufactured have a height of 25 centimeters for a length of 50 centimeters and a thickness of 10 centimeters for example, the total travel of displacement of the plates 22 and 24 for the compaction and the compression of the mixture in the mold can be d 'about fifteen centimeters at first, the pressure applied to the mixture by the plate or plates 22, 24 being relatively low. Then over a stroke of a few centimeters, the pressure gradually increases to a value for example between 5 and 10 MPa for which we arrive in the vicinity of the maximum compactness of the mixture in the mold. Generally, the slow compression of the mixture is exerted for a time necessary for the progressive evacuation of excess water and air and has the additional effect of creating inside the mixture an omnidirectional hydrostatic pressure which has several advantages:

• deletion of cleavage planes which could result from the application of one-way pressure,
• good wetting of the entire surface of the grains of the filler,
• displacement of these grains and organization of their arrangement for maximum compactness.

This last advantage is increased when we add mixing finer grains than those normally used.

The volume of water used in the mixture of plaster, filler and water to achieve compactness maximum (optimum Proctor) corresponds to the volume of water necessary for the hydration of the plaster contained in this mixture and its transformation into gypsum.

The duration of this compression phase can vary from a few seconds to 15 to 20 seconds about, depending on the characteristics particle size of the materials used.

At the end of this compression, the plates 22 and 24 are in the positions shown in the figure 2 and are substantially in abutment on the partitions internal 28.

The elements are then removed from the mold 36 which are formed by the packed and compressed mixture in the compartments 26 of the mold.

To do this, lift the upper plate 22 and, as shown in Figure 4, we bring means bearing 40 on the upper faces of the elements 36 to keep these elements in place when moving the mold 14 in vertical translation upwards until the molded elements are completely free 36 side walls 16 and internal partitions 28 of the mold.

When this is done, the means are discarded support 40 and the molded elements 36 are removed from the lower plate 24.

As shown schematically in Figure 4, the support means 40 are carried by rods vertical 42 connected at their upper ends to support and maneuvering means 44.

In this embodiment, the means 40, 42, 44 for holding the molded elements in place 36 during their release are independent of the means 10, 22, 30 compression of the mixture in the mold.

As a variant, these means can be confused especially when providing separate means of compression of the mixture in the various compartments 26 of the mold. In particular, the rods 42 can be piston rods of hydraulic cylinders and the support means 40 are then movable by these piston rods vertically over a distance corresponding to the end of the compression of the mixture in the mold. We can provide a cylinder for this. hydraulic by compartment.

In all cases, the rods 42 must have a height allowing vertical translation of the mold 14 and internal partitions 28 sufficient to demolding of the elements 36.

These elements can be used in construction very soon after they are removed from the mold, as soon as the the plaster is finished, which can take a few minutes to a few tens of minutes in depending on temperature and characteristics of the materials used.

When the compressed mixture in the mold contains hydrophobic agents mentioned above, the elements obtained can be used in bathrooms, kitchens, laundries, etc., due to their hydrophobic character. They are also usable outdoors.

Of course, the invention is by no means limited to the embodiment described and shown and applies to the manufacture of elements of construction with shapes and dimensions variety.

Claims (10)

Method of manufacturing building elements, in particular panels for interior walls of buildings, from a mixture of plaster, a filler such as sand and water, the amount of water in the mixture being slightly higher than that necessary to obtain the maximum compactness of the mixture, this process being characterized in that it consists in slowly compressing this mixture in a mold (14) with multiple compartments (26) to pack it and to evacuate the water in excess and the air contained in the mixture and reduce its volume substantially to a minimum value, then simultaneously unmold the elements (36) by translation of the mold relative to the elements (36) kept stationary and allow the plaster to set operate in the elements (36) outside the mold (14). Method according to claim 1, characterized in that it consists in compressing the mixture in the mold (14) firstly with a relatively low pressure over a relatively long stroke, then with a higher pressure over a relatively long stroke low. Method according to claim 1 or 2, characterized in that the maximum final pressure applied to the mixture in the mold is of the order of 10 MPa. Method according to one of the preceding claims, characterized in that it consists in using a delayed or relatively slow setting plaster and mixing it in a substantially uniform manner with the quantity of water mentioned above. Method according to one of the preceding claims, characterized in that the quantity of filler in the mixture is between approximately 30 and 80% by weight. Method according to one of the preceding claims, characterized in that the compressed mixture in the mold contains hydrophobic agents such as silicones for example. Method according to one of the preceding claims, characterized in that the elements (36) are panels having dimensions of the order of 25cmx 50cmx 10cm. Device for carrying out the method described in one of the preceding claims, comprising a mold (14) with rigid and non-deformable side walls (16) and with upper (18) and lower (20) openings receiving movable trays (22, 24) in translation inside the mold, means for compressing the mixture in the mold and means for demolding said construction elements (36), characterized in that the mold (14) comprises internal partitions (28) delimiting compartments for molding said elements (36) and in that the demolding means comprise means (40) for pressing on the upper faces of the elements (36) in the mold compartments and means for translating the mold parallel to said elements ( 36). Device according to claim 8, characterized in that the compression means comprise means (10, 12) for moving the upper plate (22) and / or the lower plate (24) inside parts of the mold (14) which have no internal partitions. Device according to claim 9, characterized in that the compression means are independent of the support means (40) used for demolding.

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