DE102021106268A1 - Device for producing concrete blocks and method for producing concrete blocks - Google Patents

Abstract

Device for the production of concrete blocks with - a lower mold part (5) in which at least one mold cavity (11) is formed, - an upper mold part (15) comprising at least one pressure piece (17) which can be lowered in such a way that it enters the mold cavity (11) engages, the pressure piece (17) having at least one magnet (35), and- a device (29) for applying a granular material (39) to the pressure piece (17) when it does not engage in the mold cavity (11), so that the granular material (39) adheres to the side of the pressure piece (17) facing the mold cavity (11) as a result of magnetic interaction.

Description

The invention relates to a device for the production of concrete blocks and a method for the production of concrete blocks.

A device for the production of concrete blocks comprises a lower mold part and an upper mold part. The lower part of the mold is open at the top and bottom, with the underside being closed by a horizontal base. The mold base includes one or more mold cavities into which a concrete mixture is filled. The upper part of the mold has a ram unit for compacting the concrete mixture in the mold cavities. The stamping unit includes pressure pieces which engage in the mold cavities of the lower mold part and thereby compact the concrete mixture in order to form one or more concrete blocks. The pressure pieces are also referred to as pressure plates.

During block production, the concrete mixture is poured into the upper openings of the mold cavities and then pressed by the pressure pieces, which are lowered into the mold cavities through the upper openings using a ballast unit. By shaking the base, the concrete mixture solidifies into dimensionally stable concrete blocks. Then the concrete blocks are removed from the mold through the lower openings of the mold cavities and the pressure plates are lifted off.

A typical process flow for forming concrete blocks from a layered concrete mix involves filling the form with a first filling car. The concrete mixture is pre-compacted by immersing the pressure pieces in the mold cavities. Then the tamper with the pressure pads is lifted to allow the mold to be filled using a second filling carriage. The layering of the concrete mixture forms a two-layer concrete block from a core concrete and a facing concrete applied to it. After the facing concrete has been poured in, the main compaction of the layered concrete mixture takes place. The pressure piece dips into the mold cavity and the concrete mixture is compacted by pressure from above and shock vibration. The compaction takes place until the concrete mixture has collapsed to the desired block height. The mold is then lifted to remove the block layer, while the pressure piece is still on the block surface. Then the pressure piece is lifted off the stone.

The pressure pieces used in production serve as stamping plates to design the surface of the concrete blocks. This allows, among other things, decorative effects, such as the imitation of natural stones, to be achieved.

A colored surface can be achieved by using concrete mixture, to which color particles are increasingly added during the filling process, so that the result is not a homogeneous coloring but a color mix effect. The color effect changes along the direction of filling, i.e. along or across the finished bricks.

the DE 102018121741 A1 shows a device for the production of concrete blocks with which a surface structure on the upper side of the concrete block is achieved, which is oblique to the longitudinal direction of the concrete block, so that the concrete block looks like a natural stone.

Another option for surface design is the use of iron oxides in the facing concrete mixture to achieve a rusty appearance on the stone surface. However, the dosing of the iron oxides is only possible over a large area and is largely uncontrolled.

The object is to specify an alternative device for the production of concrete blocks and their surface design. A corresponding procedure should also be specified.

The object is achieved by a device and a method for the production of concrete blocks with the features of the independent claims.

The device for producing concrete blocks comprises a lower mold part, in which at least one mold cavity is formed, and an upper mold part comprising at least one pressure piece, which can be lowered in such a way that it engages in the mold cavity, the pressure piece having at least one magnet. Furthermore, the device for the production of concrete blocks comprises a device for applying a granular material to the pressure piece when it does not engage in the mold cavity, so that the granular material adheres to the mold cavity-facing side of the pressure piece as a result of magnetic interaction.

At least one magnet, which has a magnetic interaction with the granular material, is integrated on the back of the pressure piece facing away from the mold cavity or in the pressure piece. The granular material is applied to the raised pressure plate, which is outside the mold cavity, before compaction. The granular material adhering to the pressure piece is applied to the concrete mixture in the mold cavity during compaction by the pressure piece, so that the surface of the concrete blocks is shaped by the granular material. The material adhering to the pressure piece is not distributed homogeneously, but along the magnetic field lines that run on the side of the pressure piece facing the mold cavity. The magnetic field depends on the number, strength, position and shape of the magnet or magnets. The granular material experiences a force from the magnetic field, which results in the form of adhesion, resulting in a pattern of adhering granular material that is also found on the stone surface after compaction. Embodiments of the granular material may include ferromagnetic or ferrimagnetic materials, metals, particularly iron, magnetic steel and iron oxide, glitters, and dyes. Types of granular material have a particle size that can range from fine powder with small particle size to coarse granules.

In one embodiment, the magnet is arranged on a side of the pressure piece facing away from the mold cavity or is an integral part of the pressure piece, so that the magnetic field also extends on the side facing the mold cavity.

In one embodiment, the at least one magnet includes a permanent magnet and/or an electromagnet. The permanent magnet comprises a hard magnetic material with a constant magnetic field. The electromagnet comprises a coil in which a magnetic field is formed as a result of an electric current. The magnetic field of the electromagnet and thus the magnetic interaction with the granular material can be switched on and off by means of a control device for controlling the electromagnet. The magnetic interaction can advantageously be switched on before a granular material is applied, when the pressure piece is not yet in a lowered state. The magnetic interaction can be switched off when the pressure piece is lowered and engages the mold cavity in order to support the application of the granular material onto the concrete mix.

In one embodiment, the device for applying a granular material can be moved towards the side of the pressure piece facing the mold cavity and away from the side of the pressure piece facing away from the mold cavity. To apply the granular material, the device is moved between the lower mold part and the upper mold part and placed adjacent to the pressure piece.

In one embodiment, a filling carriage is provided which is designed to fill a concrete mixture into the mold cavity and on which the device for applying a granular material is arranged. This enables the concrete mixture to be poured into the mold cavity under the filling carriage and the granular material to be applied to the pressure piece above the filling carriage at the same time.

In one embodiment, the device for applying a granular material has a spray device which is suitable for the precise application of fine-grained material, in particular powder. An alternative device for applying a granular material comprises a reservoir from which the granular material is drawn to the pressure pad due to magnetic interaction. Such a reservoir is also suitable for coarse-grained material, in particular granulate. The reservoir can be designed to be coverable, so that the granular material is only made available for application when the reservoir is open.

The method of producing concrete blocks includes: filling a concrete mixture into a mold cavity, applying a granular material to a side of a pressure piece facing the mold cavity, so that the granular material adheres to the side of the pressure piece facing the mold cavity as a result of magnetic interaction, and compacting the concrete mixture by lowering the pressure piece into the mold cavity, whereby the granular material adhering to the pressure piece is deposited on top of the compacted concrete mix.

This process gives great freedom in the surface design of concrete blocks. In one embodiment, the magnetic interaction is switched on prior to the application of the granular material, so that the granular material accumulates just before compaction, and the magnetic interaction is switched off when the pressure piece has been lowered into the mold cavity to start the application of the granular material to support the concrete mix surface. Switching on and off is possible through the use of an electromagnet. The granular material can be deposited, for example, by spraying or by magnetic attraction from a provided reservoir.

• 1 Maschinenkomponenten eines Ausführungsbeispiels einer Vorrichtung zur Herstellung von Betonformsteinen in einer perspektivischen Seitenansicht,
• 2 Maschinenkomponenten eines weiteren Ausführungsbeispiels einer Vorrichtung zur Herstellung von Betonformsteinen in einer perspektivischen Seitenansicht,
• 3 eine dreidimensionale Ansicht eines Ausführungsbeispiels eines Druckstücks auf seine vom Formnest abgewandte Seite,
• 4 eine dreidimensionale Ansicht des Ausführungsbeispiels eines Druckstücks auf seine dem Formnest zugewandte Seite,
• 5 eine Ansicht eines weiteren Ausführungsbeispiels eines Druckstücks auf seine dem Formnest zugewandte Seite,
• 6 eine dreidimensionale Ansicht eines weiteren Ausführungsbeispiels eines Druckstücks auf seine vom Formnest abgewandte Seite, und
• 7 ein Flussdiagramm einer beispielhaften Herstellung von Betonformsteinen.

Some exemplary embodiments are explained in more detail below with reference to the drawing. Show it:

• 1 Machine components of an embodiment of a device for the production of concrete blocks in a perspective side view,
• 2 Machine components of a further embodiment of a device for the production of concrete blocks in a perspective side view,
• 3 a three-dimensional view of an embodiment of a pressure piece on its side facing away from the mold cavity,
• 4 a three-dimensional view of the embodiment of a pressure piece on its side facing the mold cavity,
• 5 a view of another embodiment of a pressure piece on its side facing the mold cavity,
• 6 a three-dimensional view of a further embodiment of a pressure piece on its side facing away from the mold cavity, and
• 7 a flowchart of an exemplary production of concrete blocks.

In the figures, components that are the same or have the same functional effect are provided with the same reference symbols.

1 shows machine components of an embodiment of a device for the production of concrete blocks in a perspective side view.

The device for the production of concrete blocks has, in a manner customary in the art, a vibrating table 1, on the upper side of which is a production board 3. A lower mold part 5 is arranged on the production board 3 and has an exchangeable insert 7 with recesses which are surrounded by a frame 9, the insert 7 in the frame 9 being exchangeable. The recesses surrounded by the frame 9 form cavities 11 into which a concrete mixture is filled during the manufacture of shaped blocks. The frame 9 has retaining struts 13 on two opposite sides. The fixation of the lower mold part 5 takes place on the retaining struts 13, which in the 1 , which shows only selected machine components, not shown for the sake of clarity.

Opposite the mold cavities 11, an upper mold part 15 is arranged, which has a plurality of plate-shaped pressure pieces 17, which can also be referred to as pressure plates. The dimensions of the pressure pieces 17 correspond approximately to the recesses of the mold cavities 11. The pressure pieces 17 are connected via pressure rams 19 to a loading device 21, which can be lowered with the pressure rams 19 and the pressure pieces 17, so that the pressure pieces 17 engage in the mold cavities 11. The lowered pressure pieces 17 compress the concrete mixture in the mold cavities 11. The pressure pieces 17 each have at least one magnet.

The device for the production of concrete blocks comprises a first filling carriage 23 and a second filling carriage 27 in order to fill the mold cavities 11 with the core concrete mixture first and then with the facing concrete mixture.

The first filling carriage 23 can be moved horizontally between the upper mold part 19 and the lower mold part 15 . It is designed to be moved from a rest position beyond the production board 3 over the lower mold part 5 and to fill the mold cavities 11 with a concrete mixture designed as a core concrete mixture. In the rest position, the first filling carriage 23 is spaced far enough away from the lower mold part 5 that the loading device 21 can be lowered and the pressure pieces 17 can engage in the mold cavities 11 . On its upper side, the first filling carriage 23 has a cleaning device 25 for the pressure pieces 17, which is designed as a brush. The first filling carriage 23 is designed so that the pressure pieces 17 are also cleaned by the brush moving along them with the movement over the lower mold part 5 .

The second filling carriage 27 is designed as a front filling carriage. It can be moved horizontally between the upper mold part 15 and the lower mold part 5 . It is designed to be moved from a rest position beyond the production board 3 over the lower mold part 5 and to fill the mold cavities 11 with a concrete mixture designed as a facing concrete mixture. In the rest position, the second filling carriage 27 designed as a front filling carriage is spaced far enough away from the lower mold part 5 that the loading device 21 can be lowered and the pressure pieces 17 can engage in the mold cavities 11 . The first and second filling carriages 23, 27 are positioned on opposite sides of the finishing board 3 in their rest positions.

On its upper side, the front filling carriage 27 has a cleaning device 25 for the pressure pieces 17, which is designed as a brush. The front filling carriage is designed so that the pressure pieces 17 are also cleaned by the brush moving along them when they move over the lower mold part 5 . The second filling wagon 27 designed as a front filling wagon also includes a device 29 for applying a granular material to the pressure pieces 17, so that the granular material, as a result of a magnetic interaction between the magnets in the pressure pieces 17 and the granular material on the mold cavities 11, faces the pressure pieces 17 attached. Because of the magnetic interaction and the associated attraction of the granular material, contact between the application device 29 and the pressure pieces 17 is not necessary for the granular material to adhere. The granular material is attracted to the pressure pieces 17 due to the magnetic attraction and adhered there when it is through the front direction 29 for applying adjacent to the pressure pieces 17 has been brought.

The granular material is suitable for magnetic interaction with the magnets of the pressure pieces 17 . For example, it can be ferromagnetic or ferrimagnetic material. The granular material may include metal.

When the pressure pieces 17 are lowered for compaction, the adhering granular material remains on the concrete mixture and forms a decorative stone surface.

In this exemplary embodiment, the device 29 for application is designed as a spraying device, in which the granular material is sprayed onto the pressure pieces 17 through nozzles 31 . The device 29 for application is moved past the pressure pieces 17 with the movement of the second concrete carriage 27 during brushing and, during the backward movement into the rest position, sprays the granular material onto the pressure pieces 17, to which it adheres. When the second filling carriage 27 moves backwards, the application takes place immediately after the brush has moved along the pressure pieces 17 and has cleaned them. The granular material for spraying is usually fine-grained, which is also referred to as powder or powder in the case of very fine-grained material.

The cleaning device 25 on the first filling carriage 23 is not absolutely necessary, but has the advantage that any granular material that may still be adhering is removed from the pressure pieces 17 before the core concrete mixture is compacted.

2 shows machine components of a further embodiment of a device for the production of concrete blocks in a perspective side view. To avoid repetition, the description focuses on the differences from the embodiment in FIG 1 .

In this exemplary embodiment, the first filling carriage 23 has no cleaning device. The device 29 for applying a granular material can be moved independently of the second filling carriage 27 designed as a front filling carriage. The device 29 for application is arranged, for example, above the first filling carriage 23 and can be moved independently of this from its rest position along the pressing pieces 17 . The application device 29 comprises a reservoir 33 for the granular material. The movement of the device 29 for application moves the reservoir 33, which is open at the top, under the pressure pieces 17, so that the granular material moves to the pressure pieces 17 due to the magnetic attraction and adheres there. By choosing the distance and speed of the application device 29, the amount of adhering granular material can be controlled. In this exemplary embodiment, a grid is also provided over the reservoir 33 in order to prevent lumps of material from adhering. The provision of the granular material in a reservoir 33 is particularly suitable for coarse-grained material.

In an alternative exemplary embodiment, the reservoir 33 can be arranged as an exemplary embodiment of the device 29 for applying on the header hopper, as for the device 29 for applying in connection with FIG 1 described. However, it is then advantageous to provide the reservoir 33 with a cover that can be opened. When the front filling carriage moves from its rest position over the underside of the mold 5, the pressure pieces 17 are cleaned at the same time and the reservoir 33 is covered, because otherwise the granular material that has just been applied would be removed immediately by the brush when moving along the pressure pieces 17. When the front filling carriage moves backwards, the cover of the reservoir 33 is opened so that the granular material adheres and can then be lowered into the mold cavities 11 with the pressure pieces 17 .

3 shows a three-dimensional view of an embodiment of a pressure piece 17 on its side facing away from the mold cavity 11. The pressure piece 17 for the production of concrete blocks in a steel mold is milled.

In this exemplary embodiment, the pressure piece 15 comprises two spaced-apart magnets 35 on the side facing away from the mold cavity 11, with one circular disc-shaped magnet 35 facing the mold cavity 11 with the magnetic south pole and the other circular disc-shaped magnet 35 facing the mold cavity 11 with the magnetic north pole. A magnetic field runs between the magnets 35 . Its magnetic field lines 37 also extend in the plane of the pressure piece 11, as in 3 illustrated. The shape of the magnetic field depends, among other things, on the size, shape, position, magnet strength and number of magnets 35 . For example, instead of the two disc-shaped magnets 35, two bar magnets can be used, in which unlike or identical poles face each other. In an alternative exemplary embodiment, only one bar magnet is provided, the magnetic field lines of which run between the north pole and the south pole.

The magnets 35 can be designed as permanent magnets or as electromagnets. If there are several magnets 35, there is also a combination of permanent magnets and electromagnets possible. In an electromagnet, the magnetic field is induced by current flowing through a coil. Electromagnets can therefore be switched on and off. They can be switched on immediately before the granular material adheres and can be switched off when the pressure pad 17 is lowered in order to assist in detaching the granular material from the pressure pad 17 and depositing the granular material on the compacted concrete mix. A controller is advantageously provided for switching on and off.

4 shows the pressure piece 17 3 on its side facing the mold cavity 11 . The granular material 39 adheres along the magnetic field lines that run on the pressure piece 17 . The granular material is suitable for interacting with the magnets 35 so that it adheres to the pressure piece 17 along the field lines 37 . Embodiments of the granular material can be coloured, glittering or matt, with the effects being able to be combined using different materials. A rust effect can be achieved on the concrete blocks by using granular material 39 with iron oxide. A shiny stone surface can be formed using iron or, in particular, stainless, magnetic steel.

Due to the magnetic effect, the granular material adheres to the pressure piece 17 in patterns that can be adjusted and adapted by the magnet arrangement.

When the pressure piece 17 is lowered into the mold cavity 11 for compaction, the granular material 39 is pressed into the stone surface and adheres to it. The granular material 39 remains in the stone and forms the surface finish. The forces acting on the granular material 39 during compaction at the stone and pad surface are sufficient to cause detachment from the pad 17 and leave the granular material 39 in the concrete mix. If an electromagnet 35 is used, this process is supported by the electromagnet 35 being switched off during the compression in order to no longer expose the granular material 39 to the magnetic interaction.

5 shows a view of a further exemplary embodiment of a pressure piece 17 on its side facing the mold cavity 11 . The magnetic field features concentric circles around a magnet placed centrally on the back. The granular material 39 adheres along the magnetic field lines, with increased accumulation of granular material 39 occurring in the area of the magnet.

6 shows another embodiment of a pressure piece 17 with a plurality of magnets 35 on the side facing away from the mold cavity 11. The position of the magnets 35 can be changed. In this exemplary embodiment, a plurality of recesses 41 are provided, into which magnets 35 can be clamped. By way of example, the recesses are arranged in a rectangular and grid-like manner. The shape of the magnets 35 that can be clamped is such that they touch the side edges only in sections in order to achieve secure clamping, which is associated with a large possible treasure trove of magnet shapes. Alternative attachments are, for example, snap connections and screw connections.

The magnets 35 are interchangeable, so that the number, shape and position of the magnets 35 can be varied and thus offer great freedom for the formation of the magnetic field and the resulting surface design of the concrete blocks. In other exemplary embodiments, the positioning of the magnets 35 on the pressure piece 17 can be changed in other ways.

7 illustrates the production of concrete blocks using a flow chart. The production can with a device for production, as in connection with 1 and 2 described, take place.

In a first step 51 core concrete is filled into the mold cavities 11 by means of the first filling carriage 23 . In this step, the first filling carriage 23 moves from its resting position over the mold underside 5, fills the core concrete mixture into the mold cavities 11 and moves back into the resting position. In the same step, the pressure pieces 17 can be cleaned by the cleaning device 25 provided on the first filling carriage 23 in order to strip off any facing concrete mixture and/or granular material 39 still adhering to it. However, the cleaning of the pressure pieces 17 is not absolutely necessary, since facing concrete mixture is later applied to the compacted core concrete mixture and granular material 39 adhering to the core concrete mixture would possibly cover it. Nevertheless, the cleaning avoids that granular material 39 adhering between the layers of concrete mixture could negatively influence the stone quality.

The next step 52 provides for a pre-compacting of the core concrete mixture. In this step 52, the loading device 21 is lowered with the pressure pieces 17 so that they engage in the mold cavities 11 of the mold underside 5. The core concrete mixture is pre-compacted by immersing the pressure piece 17 . Then the loading device 21 is raised with the pressure pieces 17 and the pressure pieces 17 are lifted out of the mold cavities 11 .

In the next step 53, the facing concrete mixture is poured in. This is done by the second filling carriage 27 designed as a facing concrete carriage. It moves out of its resting position over the lower mold part 5, fills the facing concrete mixture into the mold cavities 11 and moves back to the resting position. In the same step, the pressure pieces 11 are cleaned by the cleaning device 25, which is designed as a brush and is provided on the front filling carriage.

The steps 51 to 53 mentioned above are also provided in a conventional production of layered concrete blocks. However, the next step 54 does not. In this step 54, the magnet 35 is used. Granular material 39 , for example metal powder or granulate, which is suitable for interacting with magnet 35 , is provided by means of application device 29 . The granular material 39 adheres to the pressure pieces 17 due to the interaction with the magnets 35, so that it is arranged in a pattern on the pressure pieces 17 following the magnetic field lines.

The granular material 39 can be provided by the facing concrete truck, which fills in the facing concrete mixture. In this case, the granular material 39 is applied to the pressure pieces 17 by the device 29 for application when the second filling carriage 27 is moving back. Alternatively, after the batch of facing concrete has been filled in and the pressure pieces 17 have been cleaned, the preparation and application can be carried out by a device 29 for application that can be moved independently of the facing concrete wagon.

The adhesion due to the magnetic interaction comes from one or more magnets 35 . These can be in the form of permanent magnets and/or electromagnets. The electromagnet can be switched on and off by a controller. The electromagnet is advantageously activated shortly before and/or during the preparation of the granular material 39 .

In the following step 55, the main compression takes place, which would also be provided in the conventional production. The pressure pieces 17 are lowered, immerse themselves in the mold cavities 11 and compact the layered concrete mixture.

During compaction, the granular material 39 adheres to the surface of the concrete mixture. This effect can be supported by switching off the electromagnets 35 of the lowered pressure pieces 17, since no magnetic force then acts on the granular material 39. But even with a permanent magnet, the adhesive effect of the concrete mixture outweighs the magnetic attraction, so that the granular material 39 detaches from the pressure pieces 17 during compaction and the granular material 39 sticks to the compacted concrete mixture as soon as the pressure pieces 17 are lifted.

In the following step 56, the formwork removal process takes place, which would also be provided in conventional production. The lower mold part 5 is moved upwards. The pressure pieces 17 pierce the underside 5 of the mold, so that the compacted concrete mixture remains on the production board 3 . The loading device 21 then moves upwards together with the pressure pieces 17 of the mold upper part 15 so that the finished block layer remains on the production board 3 .

Steps 51 to 56 above are repeated to produce another layer of bricks.

Of course, the pressure pieces 17 described can also be used in the production of non-layered concrete blocks. In this case, only one filling step and one compression step are provided, so that the first two steps 51, 52 are omitted. Instead of a core and a facing concrete mix, a concrete mix is used from which the whole block is formed. Before the compression step, the granular material is prepared and adhered. Only one filling carriage is required in the corresponding device for the production of concrete blocks.

The features specified above and in the claims, as well as the features that can be inferred from the illustrations, can be advantageously implemented both individually and in various combinations. The invention is not limited to the exemplary embodiments described, but can be modified in many ways within the scope of specialist knowledge.

Reference List

1

vibrating table

3

crafting board

5

lower part

7

mission

9

frame

11

mold nest

13

support brace

15

molded top

17

Pressure piece

19

pressure stamp

21

loading device

23

filling car

25

cleaning device

27

filling car

29

device for application

31

jet

33

reservoir

35

magnet

37

magnetic field line

39

granular material

41

recess

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102018121741 A1 [0007]

Claims (15)

Device for the production of concrete blocks with - a lower mold part (5) in which at least one mold cavity (11) is formed, - an upper mold part (15) comprising at least one pressure piece (17) which can be lowered in such a way that it engages in the mold cavity (11), the pressure piece (17) having at least one magnet (35), and - a device (29) for applying a granular material (39) to the pressure piece (17) when it does not engage the mold cavity (11), so that the granular material (39) as a result of magnetic interaction on the mold cavity (11) facing side of the pressure piece (17) adheres. device after claim 1 , wherein the at least one magnet (35) comprises a permanent magnet and/or comprises an electromagnet. device after claim 1 or 2 , wherein the at least one magnet (35) is arranged on a side of the pressure piece (17) facing away from the mold cavity (11) or is an integral part of the pressure piece (17). device after claim 2 or 3 , further comprising a control device for controlling the electromagnet, so that the magnetic interaction can be switched on and off. device after claim 4 , wherein the control device is designed such that the magnetic interaction can be switched off when the pressure piece (17) is lowered so that it engages in the mold cavity (11). device after claim 4 or 5 , wherein the control device is designed such that the magnetic interaction can be switched on before the application of a granular material (39) when the pressure piece (17) is not yet in a lowered state. Apparatus according to any one of the preceding claims, wherein the device (29) for applying a granular material (39) is movable towards the mold cavity (11) side of the pressure plate (17) and from the mold cavity (11) side of the pressure plate (17) is movable away. Device according to one of the preceding claims, further comprising a filling carriage (23, 27) which is designed to fill a concrete mixture into the mold cavity (11) and on which the device (29) for applying a granular material (39) is arranged. Device according to one of the preceding claims, in which the device (29) for applying a granular material (39) comprises a spray device. Device according to one of the preceding claims, wherein the device (29) for applying a granular material (39) has a reservoir (33) from which the granular material (39) is drawn to the pressure piece (17) due to the magnetic interaction. Process for the production of concrete blocks comprising: - Filling a concrete mixture into a mold cavity (11), - Application of a granular material (39) to a side of a pressure piece (17) facing the mold cavity (11), so that the granular material (39) adheres to the side of the pressure piece (17) facing the mold cavity (11) as a result of magnetic interaction , - Compacting the concrete mixture by lowering the pressure piece (17) into the mold cavity (11), the pressure piece (17) adhering granular material (39) being applied to the upper side of the compacted concrete mixture. procedure after claim 11 , the magnetic interaction being switched on before the application of the granular material (39) and the magnetic interaction being switched off when the pressure piece (17) is or has been lowered into the mold cavity (11). procedure after claim 11 or 12 , wherein the granular material (39) is applied by spraying. procedure after claim 11 or 12 , wherein the granular material (39) is provided in a reservoir (33) and the application takes place by the granular material (39) being attracted by the magnetic interaction. Procedure according to one of Claims 11 until 14 , wherein the granular material comprises metal, in particular iron, steel and/or iron oxide.

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