RU2593406C2 - Device and method for processing powder material layer - Google Patents

Abstract

FIELD: ceramic industry.

SUBSTANCE: group of inventions relates to devices and methods for treatment of powder material layer, mainly, within method of ceramic articles forming. Device contains movable transfer surface to carry and move of powder material layer, and compacting unit for compaction of powder material layer as it moves on transfer surface. At that, said device comprises facility for cutting side edges of powder material layer before compacting unit.

EFFECT: reduced non-uniformity of density of compacted layer and reduced local deformation of graphic effects, which can be created on powder layer.

11 cl, 6 dwg

Description

FIELD OF THE INVENTION

The present invention relates to devices and methods for processing a layer of powder material, mainly in the framework of the method of forming ceramic tiles or slabs.

BACKGROUND

Known devices for molding ceramic tiles, including a movable conveying surface, which is gradually served ceramic powder, so as to form its layer. The transport surface is generally formed by a conveyor belt made with the possibility of movement and braking. A layer of powder on the transport surface is passed through a compacting unit of the continuous type, i.e. one that is capable of compacting a layer of powder as it gradually progresses on the transport surface.

A compacting installation generally includes two flexible compacting surfaces located one above the other and capable of moving in the same direction as the conveying surface. Compacting surfaces are usually also formed by a corresponding movable and flexible tape. The lower compacting surface is located under the transport surface and is in contact with it so that the latter rests on it, while the upper compacting surface is located at a predetermined height above the transport surface. On a predetermined area, the compacting surfaces are guided so that they pass through a special pressing means, for example between a pair of rollers located one above the other, locally holding the upper compacting surface pressed towards the lower compacting surface to compress the powder layer located on the transport surface. The compacting unit usually also includes two parallel side edges that can move essentially in the same direction and at the same speed as the conveying surface, and which are configured to laterally limit the layer of ceramic powder on the conveying surface during compaction to achieve greater uniformity in bulk density of the powder layer in width. These lateral edges are resiliently flexible and can contract under the influence of compacting surfaces. Finally, behind the compacting unit, the conveying surface conducts a layer of compacted powder through the next cutting unit, which is configured to separate it into individual plates of desired sizes.

A device for molding ceramic tiles according to the above description is disclosed in document EP 1669177.

In such molding devices, it is necessary that when advancing to the compacting unit, the powder layer has a thickness that is almost constant along its width, which would ensure the most uniform bulk density of the compacted layer in its further advancement. However, the powder deposited on the transport surface before the compacting unit usually tends to be in the form of a trapezoidal cross-sectional layer, which does not provide a sufficiently constant thickness along its width and can cause defects in the compacted layer, at least along its edges. A known measure to overcome this drawback is to install, before the compact installation, means for restricting the powder layer from the sides. These limiting means generally include a pair of parallel edges mounted motionless above the transport surface. The powder is fed onto the transport surface into a space which is enclosed between these two lateral bounding edges holding the powder all the way to the compacting unit and giving the powder layer a cross section of a substantially rectangular shape. At the same time, however, the interaction of the stationary bounding edges and the powder layer, which advances on the transport surface, creates sliding friction, which in this case requires a significant reduction in the thickness of the powder layer at the edges, which also leads to heterogeneity in the density of the compacted layer emerging from the compacting installation, as well as local deformation of graphic effects that can be created on the powder layer.

SUMMARY OF THE INVENTION

The aim of the present invention is to overcome or at least effectively mitigate this disadvantage of the known approaches by providing a simple, rational and inexpensive solution.

This goal is achieved due to the features of the invention indicated in the independent claims. The dependent claims identify preferred and / or most preferred aspects of the invention.

In particular, the invention provides a device for processing a layer of powder material, comprising a movable transport surface configured to carry and move a layer of powder material, a compacting apparatus configured to compact a layer of powder material as it moves on the transport surface, and means for trimming the side edges of the powder material layer before the compact unit.

In particular, said trimming means is generally configured to separate and thereby remove two small side strips of powder material from a layer advancing on a transport surface in front of a compacting unit, reducing the width of this layer.

Thanks to this solution, the fixed edges bounding the powder layer on the sides are no longer required. Although in practice the powder material usually tends to form a trapezoidal cross-sectional layer, the specified powdery material layer may initially be given a wider width than that required at the inlet of the compacting unit, so that the cutting means can subsequently remove the beveled side edges of this powdery layer material, reducing its width to the required value and giving the cross-section of the layer of powder material a square shape of almost constant thickness.

Due to the absence of fixed bounding edges, the layer of powder material no longer slides on any surfaces when moving to a compacting unit, which eliminates the adverse effect of friction. Therefore, the layer of powder material at the entrance to the compacting unit can have substantially the same thickness in the center and at the edges, due to which a more uniform bulk density of the compacted layer at the outlet is ensured and graphic patterns that can be created on the layer of powder material are saved.

According to one aspect of the invention, the aforementioned trimming means may comprise a pair of blades fixed in a certain position above the transport surface. This aspect of the invention provides an advantage by providing an extremely simple solution for trimming the side edges of the powder material layer.

Each of these blades can be formed by a thin sheet oriented orthogonally with respect to the transport surface. The use of a thin sheet provides an advantage by allowing very clean to separate the edge of the layer of powder material, eliminating or at least significantly reducing the possible adverse effects that could be caused by the mechanical action of the blade on the powder material.

According to another aspect of the invention, the device may also comprise means for adjusting the distance between said blades. The advantage may be due to the ability to change the width of the layer of powder material at the entrance to the compact unit.

According to another aspect of the invention, the device may also include means for removing from the transport surface of the powder material separated by a trimmer. This aspect of the invention provides an advantage by disposing of the removed powder material, which can thus be advantageously reused to form a new layer of powder material at the beginning of the process.

According to another aspect of the invention, said withdrawal means may comprise suction means for suctioning the powder material separated by the trimming means. This solution provides an advantage, being extremely simple and providing easy disposal of the powder material.

Each suction means may include an exhaust hood located above the conveying surface and provided with an inlet for the powder material that advances on the conveying surface and an outlet that is connected to a means for creating a vacuum, allowing the powder material to be sucked through the outlet. This solution provides the advantage of being extremely efficient and productive.

In addition, the invention provides a method of compacting a layer of powder material, comprising the following steps:

- promotion of a layer of material on a mobile transport surface,

- separation of the lateral edges of the layer of powder material and, further,

- compacting said layer of powder material as it moves on said transport surface.

This method provides essentially the same advantage as the device described above, namely, it gives the powder material at the inlet to the compacting unit essentially the same thickness in the center and at the edges, due to which a uniform bulk density of the compacted layer at the outlet is ensured and graphic drawings that can be created on a layer of powder material.

According to one aspect of the invention, the method may comprise, after the cutting step, an additional step of removing powder material separated from the layer from the transport surface, which allows it to be disposed of with advantage, using it again in this process.

In order for this removal step to be the simplest and most effective, the indicated operation after the cutting step can be performed by aspirating the powder material separated from the layer.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will be apparent upon reading the following description, which is given by way of non-limiting example with reference to the images given in the accompanying drawings.

FIG. 1 is a schematic top view of a device for processing a layer of powder material according to the invention.

FIG. 2 is a section of FIG. 1 along line II-II.

FIG. 3 is a sectional view of FIG. 1 along line III-III on an enlarged scale, which schematically depicts some elements of a compact installation.

FIG. 4 is a sectional view of FIG. 3 along line IV-IV on an even larger scale.

FIG. 5 - remote element V in FIG. 1 on an enlarged scale.

FIG. 6 is a fragmentary view of FIG. 5 on the side in an isometric view in which a layer of powder material is not shown for clarity.

DETAILED DESCRIPTION OF THE INVENTION

The aforementioned drawings depict a device 100 for processing a layer Μ of powder material, typically ceramic powder, as part of a method for molding ceramic tiles or slabs.

As shown in FIG. 2, the device 100 comprises a flexible conveyor belt 105, which is infinite and encompasses a group of rollers 110 with a horizontal axis, which includes a series of non-drive supporting rollers and at least one drive roller connected to the engine, configured to drive the conveyor belt 105. Conveyor belt 105 can be made of plastic material, which ensures its low cost, low degree of contamination and simple routine maintenance procedures. The upper segment of the conveyor belt 105, essentially horizontal, forms a movable conveying surface 106, configured to carry a layer Μ of powder material and move it in a predetermined advance direction A.

The layer of powder material advances, falling from the indicated transport surface 106 into the compacting unit 115 of the continuous type (schematically indicated by a square in Fig. 1 and shown in detail in Fig. 2), configured to compact the layer Μ of powder material as it moves.

The compacting unit 115 includes two flexible compacting tapes arranged one above the other, which includes a lower compacting tape 120 and an upper compacting tape 125. Both compacting tapes 120 and 125 can be made of plastic material, which ensures their low cost, low cost degree of contamination and simple routine maintenance procedures.

The lower compacting belt 120 is infinite and encompasses a pair of rollers 121 with horizontal axes, which includes a non-driven supporting roller and a drive roller connected to the motor configured to drive the compacting belt 120 in motion. The upper segment of the compacting tape 120, essentially horizontal, forms a movable compacting surface 122, which is located under the transport surface 106 and is in direct contact with it so that the latter rests on it. The compacting surface 122 is also driven in the same direction A of advancement and at substantially the same speed as the transporting surface 106 to prevent them from rubbing against each other.

The upper compacting belt 125, in turn, is a closed loop and encompasses a pair of rollers 126 with horizontal axes, which includes a non-driven supporting roller and a drive roller connected to the motor, configured to drive the compacting belt 125 in motion. The lower portion of the compacting tape 125 forms a movable compacting surface 127, which is located above the transport surface 106 at a certain distance from it to determine the gap for the passage of the layer Μ of powder material. The compacting surface 127 is driven substantially in the same direction of advancement A and at substantially the same speed as the transporting surface 106 to prevent its friction with the powder material layer Μ.

The compacting unit 115 also includes a special pressing means which is arranged to locally hold the upper compacting surface 127 pressed against the transporting surface 106 in order to compress the layer Μ of powder material between them. In the illustrated example, the pressing means includes a pair of press rollers arranged one above the other, which includes a lower pressing roller 130 and an upper pressing roller 135, the rotation axes of which are horizontal and orthogonal with respect to the advance direction A. The lower pressing roller 130 is located under the direct contacting surface 122 and is in direct contact with it, while it is at such a height that the transportation surface 106 can be kept flat. On the other hand, the upper pressing roller 135 is located above the upper contacting surface 127 and is in direct contact with her, while he is at such a height that allows you to locally bring the specified upper compacting surface 127 to the transport surface 106, smart Shiv thickness of the gap defined therebetween, and thereby compacting the powder material layer Μ. The lower pressing roller 130 is fixedly mounted, however, the upper pressing roller 135 is mounted on the power cylinders 136, which allow its height to be changed, i.e. the distance to the lower pressing roller 130, for example, depending on the thickness of the layer Μ of the compacted powder material, and / or the compacting pressure applied thereto.

In order to make the compaction of the powder material layer Μ more gradual, the pressing means may also comprise a pair of roller assemblies located one above the other, which includes a lower roller assembly 140 and an upper roller assembly 145 located upstream of the pressing rollers 130 and 135 in terms of the advance direction A . Both roller assemblies 140 and 145 include rollers whose rotation axes are horizontal and orthogonal to the direction A of advancement. The rollers of the lower roller assembly 140 are located under and in contact with the lower compacting surface 122, they are in a plane parallel to the advancement direction A at such a height that the transport surface 106 can be kept flat. On the other hand, the rollers of the upper roller assembly 145 are located above the upper compacting surface 127 and in contact with it, they are on an inclined plane with respect to the direction of advancement at a height that allows you to gradually bring the upper the compacting surface 127 to the transporting surface 106, gradually reducing the thickness of the gap between them, and thereby gradually compact the layer слой of the powder material.

To increase the uniformity of compaction of the powder material along the width of the layer M, the compacting unit 115 also includes means for restricting the layer Μ of the powder material from the sides. In the illustrated example, said limiting means includes a pair of movable belts 150 and 155, respectively, located above the conveyor belt 105. Each of the movable belts 150 and 155 is flexible, in the form of a closed loop and covers a corresponding group of rollers 160 with horizontal axes, including including a number of non-driven support rollers and, optionally, a drive roller connected to the engine, with which the tape can be set in motion. In particular, the movable belts 150 and 155 are configured and driven in such a way that the lower length of each of them, essentially horizontal, is configured to move in the same direction A of advancement and at substantially the same speed as the transport surface 106 As shown in FIG. 4, both of these lower segments of the movable belts 150 and 155 rest on the transport surface 106 in a position between it and the upper compacting surface 127, thus forming two parallel and spaced apart edges 151 and 156, which are configured to limit Μ layer of powder material during compaction from the sides. The movable belts 150 and 155 are made of a sufficiently pliable material in the thickness direction, for example, are made of rubber or any other plastic material, and the bounding edges 151 and 156 formed by them can undergo elastic compression between the compacting surfaces 122 and 127.

Immediately after the pressing means, the compacting unit 115 is also provided with means for arranging the expansion to which the layer слой of powder materials is naturally exposed after the compacting step. In particular, this forming agent performs the function of “accompanying” the process of expansion of the powder material, namely, its deceleration to prevent the formation of cracks and / or cracks in the layer Μ after compaction.

As shown in FIG. 4, the means for arranging the expansion includes a lower plate 165, which is located under the lower compacting surface 122 and is in direct contact with it. The bottom plate 165 is substantially horizontal and is at a height that allows the transportation surface 106 to be kept flat. The forming means also includes an upper plate 170 which is located above the lower plate 165 and above the upper compacting surface 127. The lower plate 165 is stationary, however the upper plate 170 is mounted on hydraulic rams 175, which allow you to change the distance to the transport surface 106, for example, depending on the thickness of the layer Μ powder Covoy material. In addition, as can be seen from the drawings, the upper plate 170 can swing relative to the power cylinders 175, which allows it to occupy an inclined position relative to the transport surface 106. The upper plate 170 performs the function of keeping the upper compacting surface 127 pressed against the upper segment of the conveyor belt 105 with the provision on the layer Μ powder material forming pressure expansion. In general, this forming pressure may be lower than the compaction pressure generated by the press rollers 130 and 135, and the powder material may continue to expand without forming cracks or crevices in the compacted layer M.

As shown in FIG. 1, immediately before the compacting unit 115, the device 100 comprises means for trimming the edges of the powder material layer Μ which is advanced on the conveying surface 106. In particular, this trimming means is generally configured to separate and remove two small side strips S of the powder material from the edges layer M advancing on the transport surface 106 to reduce its width and give it a configuration with a cross section of a substantially square shape.

In the illustrated example, the trimming means includes a pair of blades, each of which is molded by a sheet 200 oriented orthogonally to the transport surface 106 and parallel to the advance direction A. Said sheets 200 are fixedly mounted over the transport surface 106, remaining motionless with respect to the moving layer Μ of the powder material and cutting off the side strips S.

Sheets 200 can be made of any material, but it is preferable to make them of metal, for example, to make of steel. To obtain a clear and precise cut of the powder material layer Μ, the sheets 200 are generally made quite thin, for example, they can have a thickness of 0.1 mm to 2 mm. The sheets 200 are also quite small in the direction of advance A, preferably less than 300 mm, which minimizes the friction created between them and the side edges of the powder material layer Μ, which moves into the compact unit 115. In order to further reduce this friction on the fins 200 can be applied, at least on their inner surface, a coating made of a release material, such as Teflon.

In the illustrated example, each sheet 200 is mounted on a support 205, which, in turn, is mounted on a fixed frame (not shown) of the device 100 by means of a corresponding connecting bracket 210. In particular, the support 205 is fixed on the outer surface of the corresponding sheet 200, essentially aligned with a side strip S of powder material cut off by said sheet 200. The support 205 and the corresponding sheet 200 are mounted on the connecting bracket 210 above the transport surface 106, almost in contact with the latter so as not to touch it, but to cut through sheet 200 a layer Μ of powder material essentially over its entire thickness.

In the direction A of the advancement of the transport surface 106, each sheet 200 is substantially aligned with the respective bounding edges 151 and 156 of the next compacting unit 115. Thus, the sheets 200 are configured to reduce the width of the powder material layer, so that the latter extends substantially inward between said bounding edges 151 and 156. With the sheets 200 may be connected to a tool (not shown), configured to adjust the distance between them. The specified tool may include devices configured to provide movement of the connecting brackets 210 relative to the fixed frame of the device 100, for example power cylinders or linear movement mechanisms. In order to ensure that the powder material layer Μ at the entrance to the compacting unit 115 will have a square cross section imparted to it by the sheets 200, the distance between the rear end of said sheets 200 and the front end of the bounding edges 151 and 156 (in both cases with respect to direction A advancement) should preferably be zero or at least extremely small in order to avoid loss of powder material from the sides.

The device 100 also includes means configured to discharge the powder material of the side strips S cut off by the sheets 200 from the transport surface 106. In the illustrated example, said removal means includes a system for aspirating the powder material, which, due to the construction of each sheet 200 includes a corresponding support 205. As shown in FIG. 6, the support 205 is configured in fact as an exhaust hood, i.e. has an internal cavity facing downward and blocked from below by the transport surface 106. The support 205 is also provided with a side inlet 215 located on the side opposite to the advancement direction A, which makes it possible for the powder material of the side strip S to enter the internal cavity. The support 205 is also provided with a branch pipe 220 connected to the internal cavity. The indicated branch pipe 220 is connected by a flexible tube 225 to the means schematically shown in FIG. 1 and indicated at 226, which is configured to create a vacuum, for example using a powerful fan. This vacuum creates an air stream that draws in powder material from the inner cavity of the support 205 and directs it through the outlet pipe 220 and flexible tube 225. The suction material can subsequently be separated from the air stream, for example using a cyclone collector, and enclosed in a container suitable for this purpose. (not shown).

In light of the above, the use of the device 100 allows the formation on the transport surface 106 of a layer Μ of powder material, the width of which is initially greater than the width required at the entrance to the compacting unit 115, i.e. more than the distance between the bounding edges 151 and 156. If no systems are provided for restricting powder from the sides in front of the sheets 200, the powder material initially deposited on the conveyance surface 106 will be free to form a layer Μ with a trapezoidal cross section, i.e. e. beveled side edges as shown in FIG. 2 Moving on the transport surface 106, the layer Μ then passes through sheets 200, which cut off its extreme parts, separating the two side strips S of the powder material. In other words, the sheets 200 remove the beveled edges of the powder material layer Μ, giving it a substantially square cross-sectional configuration. At the same time, the sheets 200 reduce the width of the layer Μ of the powder material, bringing it in line with the width of the entrance to the compacting unit 115, which essentially coincides with the distance between the bounding edges 151 and 156. The layer M, thus cut, is passed on the transport surface 106 through the compacting unit 115, in which it is compacted in the usual way, and the powder material of the side strips S is gradually transferred by the conveying surface 106 into the cavity of the supports 205, from which it is continuously aspirated and twater. The powder material so sucked off can be subsequently collected and reused when forming a new layer Μ at the beginning of the process.

Of course, the compacting device 100 described above can be subjected, on the part of specialists, to numerous modifications in connection with specific technical applications, which will not go beyond the scope of legal protection defined by the following claims.

REFERENCE POSITIONS

100 device

105 conveyor belt

106 transport surface

110 casters

115 compact unit

120 lower compacting tape

121 commercials

122 lower compact surface

125 top compacting tape

126 commercials

127 upper compacting surface

130 lower press roller

135 upper pressing roller

136 power cylinders

140 lower roller assembly

145 upper roller assembly

150 tape

151 edge

155 tape

156 edge

160 castors

165 bottom plate

170 top plate

175 power cylinders

200 sheet

205 pylon

210 connecting bracket

215 inlet

220 branch pipe

225 flexible tube

226 vacuum cleaner

And the direction of advancement

Μ layer of powder material

S side strips of powder material

Claims (11)

1. Device (100) for processing a layer (M) of powder material containing a transporting surface (106) made with the ability to carry and move on itself a layer (M) of powder material, and a compacting unit (115) made with the ability to compact the layer (M) of the powder material as it advances on the transport surface (106), characterized in that said device comprises means (200) for trimming the side edges of the layer (M) of powder material in front of the compacting unit (115). 2. The device (100) according to claim 1, characterized in that said trimming means comprises a pair of blades (200) located in a fixed position above the transport surface (106). 3. The device (100) according to claim 2, characterized in that each blade is formed by a sheet (200) oriented orthogonally to the transport surface (106). 4. The device (100) according to any one of paragraphs. 2 and 3, characterized in that it contains means for regulating the distance between these blades (200). 5. The device (100) according to any one of paragraphs. 1-3, characterized in that it contains a means (205, 225, 226) for removal from the transport surface (106) of the powder material separated by a cutting means (200). 6. The device (100) according to claim 5, characterized in that said means for abduction comprises a suction means (205, 225, 226) for suctioning the powder material separated by a cutting means (200). 7. Device (100) according to claim 6, characterized in that each suction means comprises a cap (205) located above the transport surface (106), provided with an inlet (215) for the powder material, which is advanced on the transport surface (106) and an outlet (220), which is connected to means (226) for creating a vacuum, configured to suction the powder material through the outlet (220). 8. The device (100) according to claim 1, characterized in that the distance between the rear end of the specified cutting means (200) and the front end of the bounding edges (151, 156) of the compacting unit (115) is zero or one that avoids loss of powder material on the sides. 9. A method of compacting a layer (M) of powder material, comprising the following steps:
- advancing a layer (M) of powder material on a mobile transport surface (106) and
- compacting said layer (M) of powder material as it moves on said transport surface (106),
characterized in that said compaction step is preceded by a step of cutting off the lateral edges of the powder material layer (M). 10. The method according to p. 9, characterized in that it contains an additional step of removal from the transport surface (106) of the powder material separated from the layer after the cutting step. 11. The method according to p. 10, characterized in that the stage of abstraction ensures the absorption of the powder material separated from the layer (M), after the cutting stage.

Images