Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B5/00—Producing shaped articles from the material in moulds or on moulding surfaces, carried or formed by, in or on conveyors irrespective of the manner of shaping
  • B28B5/04—Producing shaped articles from the material in moulds or on moulding surfaces, carried or formed by, in or on conveyors irrespective of the manner of shaping in moulds moved in succession past one or more shaping stations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B17/00—Details of, or accessories for, apparatus for shaping the material; Auxiliary measures taken in connection with such shaping
  • B28B17/0063—Control arrangements
  • B28B17/0081—Process control
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B3/00—Producing shaped articles from the material by using presses; Presses specially adapted therefor

Definitions

• the invention relates to a method and a device for manufacturing building blocks by high pressure molding of a mixture of a hydraulic binder such as plaster, an inert filler such as sand and water.
• a hydraulic binder such as plaster
• an inert filler such as sand and water.
• This process essentially consists in molding under high pressure the mixture of plaster, sand and water for a sufficient time, of the order of 2 to 3 minutes, corresponding to the hydration under pressure of the plaster which results in an expansion upset of the plaster inside the mold, as well as by a densification and a reorientation of its crystal lattice.
• the building blocks thus obtained have remarkable characteristics: a compressive strength much greater than 100 kg / cm 2 , a hardness equivalent to that of soft stone, good resistance to humidity and frost, and a dimensional precision of the order of 1/10 th of a millimeter, which allows them to be mounted directly on top of each other without the inter ⁇ position of traditional seals between the blocks.
• the present invention relates to important improvements to this process, as well as to means for implementing this process, which make it possible to further improve the characteristics of the building blocks. mentioned above, to standardize their quality and to reduce their cost price.
• the invention provides for this purpose a method of manufacturing building blocks from a mixture of a hydraulic binder such as plaster, an inert filler such as sand and water, which is molded under pressure for a sufficient time to obtain hydration under pressure of the hydraulic binder and a densification of its crystal lattice, characterized in that it consists in placing a metered quantity of the mixture in a mold with non-deformable side walls and with upper horizontal plates and lower, displaceable in vertical translation inside the mold with small clearance relative to the side walls, then moving lente ⁇ ment at least 1'un trays 1 to r inside the mold on races successively determined for compacting the mixture to inside the mold, then to give a predefined height to the block to be obtained by exerting progressively high pressure on the mixture in the mold, at my hold these plates in place for the aforementioned period during which a controlled expansion of the hydraulic binder takes place in the mold, then move aside one of the plates and unmold the block by moving the other plate towards the interior of the mold.
• the slow compression of the mixture placed in the mold has the effect, successively, of packing the mixture in the mold by reducing its overrun, to expel the air contained in the mixture and to accelerate the wetting of the mixture thanks to the pressurization of water, to chase out of the mold a possible excess of water relative to the amount of water just necessary for the hydration of the plaster, and to define with precision the height (or dimension between the horizontal plates of the mold) of building block to be obtained. Keeping the mold plates in place, in the position they occupy at the end of the compression phase, makes it possible to maintain this height during the next phase, which is a phase of hydration under pressure and of thwarted expansion of the plaster in the mold.
• the building blocks thus produced have well-defined dimensions and a resistance to compression which is at least equal to a predetermined value.
• this method also consists in detecting the increase in pressure in the mold resulting from the thwarted expansion of the hydraulic binder, to define the end of the duration of thwarted expansion in the mold and unmold the building block, when this pressure has reached a predetermined value.
• this predetermined value of the pressure in the mold will only correspond to around 70-90% of the complete hydration of the hydraulic binder in the mold, so as to reduce the effort to be provided for demolding the blocks. of construction and wear of the molds.
• the invention also provides a device for implementing this method, characterized in that it comprises:
• the means for holding the plates in place in the mold can be constituted either by the hydraulic jack (s) of the aforementioned press, or by mechanical and / or hydraulic means independent of this press.
• the device may also include means for detecting the increase in pressure of the mixture in the mold, resulting from the thwarted expansion of the hydraulic binder.
• At least the upper plate of the mold comprises an oblique rim on at least a part of the periphery of its contact face with the mixture in the mold, to form a chamfer (continuous or discontinuous) on at least part of the upper peripheral edge of the building block.
• This chamfer avoids the risks of cracking or bursting of the upper peripheral edge of the building block, when the mold plates are released at the end of the thwarted expansion phase, before demolding.
• the appearance of a construction formed by placing these blocks on top of each other is improved.
• the hydraulic press comprises upper and lower plates between which the mold is placed and which are connected by a mechanical transmission capable of positively defining a determined distance between the plates of the press, corresponding to the desired height of the building block, and to ensure the parallelism of these plates.
• the invention makes it possible to reliably and safely automate the process for manufacturing building blocks, to improve and standardize their quality, and to very significantly increase their rate of manufacture.
• FIGS. 1, 2 and 3 are diagrammatic views from above, in vertical section and from below respectively, of a building block according to the invention
• FIG. 4 is a schematic view in vertical section of a mold for manufacturing this block
• FIG. 5 is a schematic view from above of this mold, from which the upper plate has been removed;
• FIG. 6 schematically illustrates the different manufacturing stations of this block, in one embodiment of the invention;
• FIGS. 7 and 8 are views in vertical section and from above, respectively, of an alternative embodiment of a mold
• FIG. 9 schematically shows the stations of an installation using the mold of Figures 7 and 8.
• the building block which has been shown in Figures 1 to 3 is substantially identical to that which has been described in International Application WO 88 / 03916 and is of rectangular rectangular shape, with dimensions which are for example 15cm x 15cm x 30 cm.
• the invention also allows the manufacture of blocks having different shapes and dimensions.
• the upper face 12 of this block has protrusions 14 of low height, of square or circular shape for example.
• the lower face 16 of the block comprises a ca ⁇ vity 18 of a relatively large volume (of the order of 30% of the total volume for example), which extends over a certain height inside the block 10 and of which the plug on the lower face 16 of the block is delimited by longitudinal edges 20 and transverse edges 22 which define the housings of the projections 14 of the upper face of another block.
• the lower face 16 of the block com ⁇ carries a groove or a longitudinal channel 24 extending over its entire length, which communicates with the cavity 18 and which opens at one of its longitudinal ends in a vertical groove 26 formed over the entire height of the block, in one of its vertical end faces.
• the blocks 10 are intended to be placed on top of each other and next to each other, all being oriented in the same direction, to form a wall comprising horizontal rows of blocks in which the blocks are offset from one another by half a length from one row to another.
• Relatively liquid plaster is poured twice into the vertical grooves 26 to partially fill the cavities 18 of the blocks by covering the projections 14 on the upper faces of the lower blocks, then to fill the vertical grooves 26.
• a chamfer 28 is formed on at least part of the peripheral edges of the upper and lower faces of the building block. Identical chamfers can also be formed on the vertical edges of the block.
• FIGS. 4 and 5 schematically represent a mold used for the manufacture of the block represented in FIGS. 1 to 3.
• This mold comprises four vertical steel walls 30, which are rigidly assembled together, preferably by bolts 32 and which are positioned in relation to one another by means of centering pins 34 to precisely define the length and the width of the molding cavity, with a dimensional tolerance of the order of a few hundredths of a milli ⁇ meter.
• the inner faces of the vertical walls 30 are ground to be perfectly smooth and flat.
• One of the vertical walls 30, forming one of the small vertical end faces of the mold has over its entire height a vertical projection 36 of semi-cylindrical shape intended to form the vertical groove 26 of the building block to be obtained.
• the vertical walls 30 of the mold have a height greater than that of the block to be obtained, so as to re- ire between them the upper plate 38 and the lower plate 40 of the mold.
• the vertical walls 30 of the mold When the height of the block to be obtained is 15 cm, the vertical walls 30 of the mold will have a height of between 25 and 30 cm approximately.
• the mold plates are rectangular steel plates, dimensioned so that they can be moved by vertical translation inside the mold, with a small clearance of a few tenths of a millimeter relative to the vertical walls. Furthermore, the internal faces of the vertical walls 30 form with the vertical a small draft angle of the order of 0.5 * to facilitate demolding of the building block.
• the lower face of the upper plate 38 of the mold has two small cavities 42, the shapes of which correspond to those of the projections 14 of the upper face of the building block to be obtained, and an oblique peripheral rim 44 for forming the chamfer 28 of the block. to obtain.
• This oblique rim can be provided only on a part of the periphery of the lower face of the plate 38.
• a small vertical face of the plate 38 has a semi-cylindrical groove corresponding to the vertical projection 36.
• the upper face of the lower plate 40 carries a core 46 intended to form the cavity 18 and the longitudinal channel 24 in the lower face of the block to be held.
• a small vertical face of this plate 40 and of the core 46 has a vertical semi-cylindrical groove, intended to receive the vertical projection 36 of the corresponding side wall 30 of the mold.
• the upper edge of the plate 40 also includes an oblique peripheral edge for forming the aforementioned chamfer 28 of the building block. As before, this oblique rim can be provided only on a part of the periphery of the plate 40.
• at least one of the large vertical walls 30 of the mold is easily attached to the other walls by any suitable means, for example comprising hinges and / or locking levers.
• this large wall 30 can facilitate the demolding of the building block.
• this wall 30 can be intended to receive on its internal face a plate of any suitable material intended to form a facade facing on the building block.
• FIG. 6 The different positions of a device for manufacturing a building block according to the invention have been shown diagrammatically in FIG. 6.
• the first station of the device according to the invention is a mold filling station 50.
• the mold 50 rests on a support surface 52, which can be part of means for transferring the molds between the different stations of the manufacturing device.
• the in ⁇ lower plate 40 of the mold is also carried by this support surface 52, so as to occupy a defined position inside the mold.
• Means 54 make it possible to pour inside the mold a metered amount of a mixture 56 of a hydraulic binder such as plaster, an inert filler such as sand, and water.
• the means 54 for supplying this mixture are advantageously designed to also carry out the humidification of a dry mixture of plaster and sand with an amount of water which will be substantially equal or slightly greater than the amount of water required.
• the mold is then transferred to the next station, designated by the reference B, where the upper plate 38 of the mold is placed in the mold and rests on the mixture 56 of plaster, sand and water.
• one or other of the stations A and B or the two stations may include a vibrating table making it possible to start compacting the mixture 56 in the mold, evacuating the occluded air and better anchorage.
• the next station, designated by the reference C essentially comprises a hydraulic press with two movable horizontal plates 58 and 60 between which the mold 50 is placed.
• One or more hydraulic cylinders 62 make it possible to move the plates of the press, for example in synchronism , in opposite directions to bring them closer and to move them apart.
• the piston rods of the cylinders 62 are supported on the upper plate 58 of the press while their cylinders are carried by a horizontal plate 64 movable in vertical translation and connected by ti ⁇ rants 66 to the lower plate 60 of the hurry.
• the tie rods 66 make it possible to obtain and maintain the desired distance between the plates of the mold, and are the seat of tension forces which can be measured to control the proper execution of the process.
• the upper plate 58 of the press is applied to the upper plate 38 of the mold while the vertical walls 30 and the lower plate 40 of the mold rest on the lower plate 60 of the press.
• the compression of the mixture 56 in the mold is carried out slowly, preferably in two stages:
• the distance between the plates 38 and 40 of the mold, corresponding to the desired height of the block to be obtained, is preferably defined positively by a mechanical transmission connecting together the plates 58 and 60 of the press and ensuring their parallelism.
• the station D may for example comprise means 68 for supporting the mold and the lower plate 40, and means for bearing on the upper plate 38, these means possibly being of the mechanical type, for example levers 70 mounted at rotation on a support 72, and / or of the hydraulic type, for example jacks 74 carried by the support 72.
• the mold 50 is kept at station D for a period sufficient for hydration of the plaster to occur at around 70-90% inside the mold 50. This period can vary from 1.5 to 5 min approximately, depending ⁇ tion of the temperature, the type and quantity of plaster used, and the degree of hydration of the plaster that one wants to obtain under pressure.
• the increase in pressure in the mold 50, which results from the contrared expansion of the plaster, can be very significant and reach values of the order of 100 kg / cm 2 .
• the support means 70, 74 will therefore have sufficient strength to oppose the pressure exer ⁇ ced on the upper plate 38 of the mold.
• the pressure inside the mold is detected by suitable means, so that the support means 70, 74 release the upper plate 38 from the mold as soon as this pressure has reached a predetermined value.
• a means 76 for measuring the pressure in a jack 74 there is shown diagrammatically at station D a means 76 for measuring the pressure in a jack 74, this means 76 being associated with a means 78 for controlling the jack.
• the means 70, 74 of support on the upper plate 38 of the mold are discarded and the mold is transferred to the following station designated by the reference E, where the upper plate 38 of the mold is re ⁇ drawn.
• the mold is then transferred to the following station, designated by the reference F and which is a demoulding station.
• the vertical walls 30 of the mold are immobilized between stops, and one or more hydraulic cylinders 80 exert a significant force on the lower plate 40, to push it upwards and allow the extraction of the block 82 by means 84 for taking and transfer, the block 82 being manipulable and usable as soon as it leaves the mold.
• the force provided by the cylinder (s) 80 can be very large (for example of the order of 100 kg / cm 2 ) over a short stroke, after which the vertical clearance of the faces 30 facilitates the upward movement of the lower plate 40.
• the station occupied the longest by the molds is station D where the counterbalanced expansion of the plaster occurs for a period of between approximately 1.5 and 5 min.
• the device according to the invention can therefore include several of these stations, arranged to be de ⁇ placeable on a path of determined length between station C and station E, for example by means of a carrousel comprising ten stations D, turning step by step between station C and station E.
• the entire device can also be in the form of a rotating carousel between stations A, C and F, and comprising a certain number of stations D, as well as means for fitting and removing the upper covers 38 from the molds.
• the production rate is then limited only by the duration of operations at station C, which is around fifteen seconds, and can therefore reach around 200 blocks / hour.
• This rate can be greatly increased by performing the first compression time of the mixture in the mold at station B, and the second time at station C.
• the device according to the invention only includes the stations
• the upper plate 38 of the mold then being permanently fixed under the upper plate 58 of the press.
• the operations of compacting the mixture in the mold, of compacting and holding in place the plates of the mold during the thwarted expansion of the plaster are carried out at the press.
• the production rate is then around twenty blocks per hour (if only molds with a single imprint are used), but is obtained by means of a relatively simple machine comprising only filling stations. molds and mold release blocks and a hydraulic press. Two workers are sufficient to ensure the operation of this machine.
• the device according to the invention when the device according to the invention is designed to offer a high production rate, it can be provided at the outlet of a plaster production installation and then use the hot plaster leaving directly from this installation, which reduces moreover the duration of the expansion thwarted and is favorable to the increase in the rate of production.
• FIGS 7 and 8 There is shown schematically in FIGS 7 and 8 an alternative embodiment of the mold according to the invention.
• the mold essentially consisting of the four vertical walls 30, the upper plate 38 and the lower plate 40, is surrounded and supported by at least one rigid frame 86 of rectangular shape on the sides of which the vertical walls 30 of the mold are detachably fixed.
• Two adjacent sides of the frame 86 comprise means 88 associated with the corresponding vertical walls 30 of the mold to move them transversely inwards and outwards of the mold, as indicated by the double arrows in FIG. 8, on a short distance, for example of the order of 1 to 10 mm approximately.
• These means 88 can be mechanical, for example screw, cam or lever, or hydraulic.
• the base of the frame 86 may also include means 90 on which the lower plate 40 of the mold rests.
• the upper plate 38 of the mold comprises means 92, for example mechanical, for locking in position between the vertical walls 30 when the upper plate 38 is at a predefined distance from the lower plate 40, this distance being equal to the height of the block to be manufactured.
• the installation represented in FIG. 9 comprises a certain number of stations A, B, C, D, E, F and G to which the mold of FIGS. 7 and 8 is successively brought by transfer means represented schematically by the arrows joining the various stations of Figure 9.
• transfer means represented schematically by the arrows joining the various stations of Figure 9.
• these transfer means will act on the frame 86 which surrounds and supports the mold itself.
• the first station A of the installation of FIG. 9 is a station for filling the mold with a mixture of plaster, sand and water.
• the lower plate 40 of the mold is supported on the support means 90, and the two movable vertical walls 30 of the mold have been brought together, to delimit between them and with two other vertical walls 30 a volume of molding to the size of the block to be manufactured.
• the upper plate 38 of the mold has been moved aside, to allow the mold to be filled with the mixture of plaster, sand and water.
• next station B the upper plate 38 is placed on the mold and the wet mixture placed in the mold can be slightly packed and compressed as already described with reference to FIG. 6.
• the next station C is the station for slowly compressing the mixture in the mold, and includes a press which will act on the upper plate 38 to compress the mixture in the mold to the desired height of the block to be manufactured.
• the means 92 are actuated to block the upper plate 38 in position on the vertical walls 30 of the mold, then the mold and its frame 86 are transferred from station C to station E for opening the mold.
• the duration of the path between these two positions corresponding to the duration of the thwarted expansion phase D of the plaster in the mold. This period may be sufficient for the hydration of the plaster to be complete between stations C and E, which guarantees the dimensional stability of the blocks after they are removed from the mold.
• the means 92 are actuated to release the upper plate 38 and the means 88 are also actuated to spread the two movable walls 30 of the mold outwards.
• the mold and its frame 86 are then transferred to station F where it suffices to lift the lower plate 40 to release the building block. Due to the prior spacing of the movable walls 30 of the mold, this release takes place without problem and without friction of the block on the internal faces of the walls 30 of the mold, and therefore without significant wear of these faces.
• station G is a station for cleaning the mold, for example by means of pressurized air jets or pressurized water jets, which may also be optionally a station for laying a facing plate on the internal face of one of the walls 30 of the mold.
• the mold and the frame 86 are finally brought back to the filling station A, where the means 88 can be actuated again to replace the movable walls 30 in molding position, before filling the mold with the mixture of plaster, sand and water.
• the mold of FIGS. 7 and 8 has very significant advantages, insofar as it makes it possible to avoid any problem with demolding, and to effect a " total hydra ⁇ tion of the plaster under pressure in the mold, all by guaranteeing a high dimensional precision of the order of lOth of a millimeter on the building block thus manufactured.
• the frame 86 which surrounds the mold is of robust construction to be rigid and undeformable.
• the frames 86 each equipped with a mold can be jux ⁇ tapped, for example by two or four, to be transferred together from one station to another in the installation of Figure 9, which is then equipped with a multiple press, to double or quadruple the rate of fabrication.
• the method and the device according to the invention are applicable to the manufacture of elements and building blocks having shapes and dimensions different from those of the block shown in FIGS. 1 to 3, and in particular solid blocks, blocks with multiple cavities, planar elements, chains, etc.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Ceramic Engineering (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Automation & Control Theory (AREA)
• Press-Shaping Or Shaping Using Conveyers (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)

Applications Claiming Priority (3)

Publications (2)

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Family Applications (1)

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• 1991
  • 1991-05-15 FR FR9105870A patent/FR2676386A1/fr active Pending
• 1992
  • 1992-05-14 WO PCT/FR1992/000424 patent/WO1992020502A1/fr active IP Right Grant
  • 1992-05-14 DE DE69230802T patent/DE69230802D1/de not_active Expired - Lifetime
  • 1992-05-14 AU AU19084/92A patent/AU670748B2/en not_active Ceased
  • 1992-05-14 US US08/146,154 patent/US5507996A/en not_active Expired - Lifetime
  • 1992-05-14 AT AT92911263T patent/ATE190549T1/de not_active IP Right Cessation
  • 1992-05-14 EP EP92911263A patent/EP0619773B1/de not_active Expired - Lifetime
  • 1992-05-14 JP JP4511259A patent/JPH06509290A/ja active Pending
• 1993
  • 1993-11-15 OA OA60435A patent/OA09844A/fr unknown

Non-Patent Citations (1)

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