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Title:
UNIT AND METHOD FOR COMPACTING CERAMIC PRODUCTS
Document Type and Number:
WIPO Patent Application WO/2020/261310
Kind Code:
A1
Abstract:
The unit for compacting ceramic products comprises a matrix (2) wherein at least one opening (22) is made; a punch (3) arranged inside said opening (22) to define the bottom of a die for compacting the powders suitable for making said ceramic products; an ejector block (9) placed under said matrix (2) and associated with said punch (3). The compaction unit comprises a blowing member which may be activated in the volume between said matrix (2) and said ejector block (9), and signaling means (70) configured to detect the presence of dispersed dust (P) in said volume between said matrix (2) and said ejector block (9), so that the production chain is blocked for removing said dispersed powders.

Inventors:
BARDELLI, Simone (IT)
Application Number:
IT2020/050161
Publication Date:
December 30, 2020
Filing Date:
June 26, 2020
Export Citation:
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Assignee:
REALMECCANICA S.R.L. (IT)
International Classes:
B28B3/08; B28B17/04; B08B5/02; B30B15/00
Attorney, Agent or Firm:
MANZELLA & ASSOCIATI (IT)
Download PDF:
Claims:
Claims

1 . A unit for compacting ceramic products, comprising a matrix (2) wherein at least one opening (22) is formed, defined by a plurality of lateral surfaces (23); a punch (3) arranged inside said opening (22) to define the bottom of a cavity (30) of a die for compacting the powders suitable for making said ceramic products; an ejector block (9) placed under said matrix (2) and associated with said punch (3), said ejector block (9) being axially movable to said opening (22) for removing the ceramic products produced at said die following the process of compaction of said powders; a blowing member activatable in the volume between said matrix (2) and said ejector block (9); characterized in that it includes means for detecting (70) the presence of dispersed powders (P) in said volume between said matrix (2) and said ejector block (9), comprising means for checking (5) the sediment of said dispersed powders (P) and means for signaling (7) said presence of dispersed powders (P), activatable by said checking means (5) and suitable for blocking the production chain during said process of compaction of the powders in said cavity (30) of the die.

2. A compaction unit as in claim 1 , characterized in that said checking means comprise a frame (50) associated with said matrix (2) through a plurality of support members (24) so that it is vertically movable below the lower surface (21 ) of the same matrix (2).

3. A compaction unit as in claim 2, characterized in that said frame (50) develops at least partially along the perimeter of said opening (22) and is kept spaced away from said lower surface (21 ) of the die (2) by means of said support members (24).

4. A compaction unit as in claim 1 or 2, characterized in that said signaling means (7) comprise a sensor member associated with the lower surface (21 ) of said matrix (2) by means of a support member (6).

5. A compaction unit as in claim 2, characterized in that said checking means (5) comprise at least one protrusion (51 ), arranged in front of said signaling means (7) and protruding in a substantially orthogonal way from said frame (50) in direction of said ejector block (9), and in that said signaling means (7) comprise a sensor member associated with said ejector block (9) by means of a support member (6).

6. A compaction unit as in any one of the preceding claims, characterized in that said signaling means (7) comprise a button-sensor device (71 ) associated with said lower surface (21 ) of the matrix (2).

7. A compaction unit as in any one of the preceding claims, characterized in that said checking means (5) comprise a plurality of strips (55) capable of acting as sensor members, said strips (55) being suitably positioned parallel at the sides of said opening (22).

8. A compaction unit as in claim 2, characterized in that said checking means (5) comprise a plurality of brackets (57) which extend coplanar from said frame (50), a stem (58), developing from each bracket (57) towards said ejector block (9) and ending at the bottom in a plate (59).

9. A compaction unit as in any one of the preceding claims, characterized in that said detection means (70) comprise a plurality of button-sensor devices (71 ), capable of acting as checking means (5) distributed on the lower surface (21 ) of said die (2) or on the upper surface of said ejector block (9) peripherally to said opening (22).

10. A method for compacting ceramic products comprising the steps of:

a. arranging a die for compacting powders suitable for making said ceramic products; b. feeding said ceramic powders inside said die;

c. starting the process of compaction of the ceramic powders inside said die;

d. detecting the possible presence of the dispersed powders in the volume between a die matrix (2) and an ejector block (9) movable axially below said matrix (2) for removing the produced ceramic products;

e. report said possible presence of dispersed powders (P) to control means so as to interrupt the compacting process of the ceramic powders;

f. removing said dispersed powders (P) before resuming the process of compaction of the ceramic powders inside said die.

Description:
Description

UNIT AND METHOD FOR COMPACTING CERAMIC PRODUCTS

Technical field

[01 ] The present invention relates to a unit and a method for compacting ceramic products.

Prior art

[02] The need to mass produce ceramic products, in particular products such as tiles and the like, has long been known.

[03] According to a known forming techniques, the tiles are formed starting from ceramic powders suitably compacted inside the cavities of a die. In particular, the ceramic powder is placed into the cavities of the die through special casting means and is then compacted by means of a press to obtain the desired shape of the tile. An apparatus of this type is illustrated, for example, in patent EP 2 318 189 B1.

[04] More specifically, the production line generally includes a plurality of devices designed to feed ceramic powders homogeneously, for example mobile hoppers; a matrix having one or more dies of suitable dimensions designed to shape the product; handling means through which the semi-processed products are transported from one processing step to the next; a press, which compressing the ceramic powders inside the cavities enables the thickening of the particle to be obtained and a simultaneous expulsion of the gases incorporated in the powders. The ceramic tiles formed this way are subsequently extracted from the dies and moved to the following processes, such as for example drying and glazing, by means of an ejector block which pushes the tiles out of the dies.

[05] The production chain described above is aimed at the production of semi-finished products in series. During this production, the use of powders and the need to move the products from one process step to the next, highlighted the problem of a possible dispersion of these powders in the surrounding environment. In particular, the dispersed powders can settle in the interstices between the moving parts of the handling apparatus. The progressive accumulation of these powders leads to possible deterioration and breaking of the mechanical components.

[06] Furthermore, the deposits of dust, obstructing the aforementioned interstices between the moving parts of the handling apparatuses, modify the relative positions between the individual members of the production chain; the consequence is a reduction in the precision with which the production process forms the tiles causing inhomogeneity in compaction and irregularities in the shape of the tiles and the possible die breakage.

[07] A further consequence in the formation of ceramic dust deposits is the need to stop the production chain to clean the surfaces affected by the phenomenon, causing slowdowns in production and therefore economic damage. The cleaning of the dies is currently made normally by means of jets of compressed air. [08] A solution to the problem of dust accumulation involves the inclusion in the circuit of special suction apparatuses. After the compacting phase of the powders by the press in the die, the suction apparatus collects the dispersed powders and accumulates them in a collector tank. Such a solution is illustrated, for example, in the utility model ES1054147.

[09] However, this solution is not fully effective, since the presence of suckers involves the use, and therefore the periodic replacement, of filtering elements which can produce a significant impact on the production chain.

[10] In particular, it is complained that a malfunction of the parts responsible for cleaning the dies can easily cause an accumulation of dust such as to cause damage to the dies, with obviously significant economic loss.

[11 ] Patent application EP 3 401 068 A2 illustrates a die for ceramic products comprising a bellows adapted to isolate the working environment and a pneumatic cleaning circuit. Appropriate means for detecting the operation of the die during the operating step are suitable for detecting the pressure existing inside the insulation bellows and the air pressure in the pneumatic cleaning circuit. However, the illustrated solution does not solve the problem of dust accumulation, in particular in the area below the matrix, which causes die damage.

Disclosure

[12] The present invention aims at solving the aforementioned problems by devising a compaction unit for ceramic products which allows the removal of the dispersed powders during the compacting and transporting process to be performed optimally.

[13] Within this aim, a further object of the invention is to provide a compaction unit which is capable of identifying and signaling the presence of dispersed powders.

[14] Another object of the invention is to provide a compaction unit which is capable of safely avoiding damage to the dies by the dispersed powders.

[15] Another object of the invention is to provide a compaction unit which is capable of intervening on the production chain if a lowering of the blowing capacity for the removal of the powders is detected.

[16] Another object of the invention is to provide a compaction unit that allows the implementation of the cleaning process even to existing plants.

[17] A further object of the invention is to provide a compaction unit with great constructional and functional simplicity, certainly reliable in operation, versatile in use, and having relatively inexpensive cost.

[18] The mentioned objects are achieved, according to the present invention, by the compaction unit for ceramic products according to claim 1 .

[19] The compaction unit of ceramic products comprises a matrix in which at least one opening defined by a plurality of lateral surfaces is made, a punch arranged inside the opening to define the bottom of a cavity of a die for compacting powders suitable for making ceramic products, an ejector block placed under the matrix and associated with the punch, wherein the ejector block is axially movable with respect to the opening for the removal of the ceramic products made at the die following the process of powder compaction.

[20] The unit includes a blowing member which may be activated in the volume between the matrix and the ejector block.

[21 ] According to the present invention, the compacting unit comprises means for detecting the presence of the dispersed powders in the volume between said matrix and said ejector block.

[22] Said detection means comprise means for checking the deposit of the dispersed powders and means for signaling the presence of said dispersed powders.

[23] Said detection means may be activated by said checking means and are capable of blocking the production chain during the process of compacting the powders in the cavity.

[24] Advantageously, said checking means comprise a frame associated with said matrix by means of a plurality of support members so as to be vertically movable below the lower surface of the same matrix.

[25] According to an embodiment of the invention, said frame develops at least partially along the perimeter of said opening and is kept away from the lower surface of said matrix by means of said support members.

[26] According to an embodiment of the invention, said checking means comprise at least a protrusion arranged in front of said signaling means and which is protruding in a substantially orthogonal way from said frame in the direction of said ejector block.

[27] Advantageously, said signaling means comprise a sensor member associated with the ejector block by means of a support member.

[28] Preferably, said signaling means comprise a sensor member associated with the lower surface of the said matrix by means of a support member.

[29] Advantageously, said signaling means comprise a sensor-button device associated with the lower surface of the said matrix.

[30] According to a particular aspect of the invention, said checking means comprise a plurality of strips suitable to act also as sensor members, said strips being suitably positioned parallel at the sides of said opening.

[31 ] According to an embodiment of the invention, said checking means comprise a plurality of shelves which extend from said frame in the same plane, from each shelf developing, towards the ejector block, a stem ending in a plate at the bottom.

[32] According to an embodiment of the invention, said detection means comprise a plurality of sensor-button devices suitable also to act as checking means distributed on the lower surface of the matrix or on the upper surface of the ejector block peripherally to the opening.

[33] The present invention also relates to a method for compacting ceramic products comprising the steps of:

a. arranging a die for compacting powders suitable for making said ceramic products; b. feeding said ceramic powders inside said die;

c. starting the process of compaction of the ceramic powders inside said die;

d. detecting the possible presence of the dispersed powders in the volume between a die matrix and an ejector block movable axially below said matrix for the removal of the produced ceramic products;

e. signaling said possible presence of dispersed powders to control means so as to interrupt the compacting process of the ceramic powders;

f. removing said dispersed powders before resuming the compacting process of the ceramic powders inside said die.

[34] According to an embodiment of the invention, the step d. of detecting the possible presence of dispersed powders is determined by detecting the movement of checking means in contact with said dispersed powders present in the volume between said die matrix and said ejector block.

Best mode

[35] With particular reference first to Figures 1 - 3, the compaction unit according to the invention is indicated as a whole with reference number 1 , in particular for compacting ceramic powders in the ceramic tile pressing process. The compaction unit 1 comprises, in a per se known manner, a matrix 2 defining one or more dies and a casting system, not shown in the figures, necessary for depositing ceramic powders in the dies, such as for example a hopper. The compaction unit 1 further comprises at least one press suitable for compressing the ceramic powders deposited by the casting system, as well as handling means suitable for transferring the produced ceramic products to subsequent processing steps. For simplicity, the press and the handling means are not shown in the figures.

[36] In particular, the compaction unit 1 comprises a matrix 2 forming a lower surface 21 and affected by at least one opening 22. In the case illustrated by way of example, the matrix 2 is equipped with a pair of openings 22 but it is obviously possible to provide that the number of the openings 22 is different. Each opening 22 is limited by a plurality of lateral surfaces 23 which extend along the thickness of the matrix 2.

[37] Inside each opening 22 a punch 3 is arranged, which is suitable for defining the bottom of a cavity 30 of the die for compacting powders suitable for making the ceramic products.

[38] The punch 3 is associated with an ejector block 9 positioned below the matrix 2 and axially movable with respect to the openings 22 for the removal of the ceramic products made at the dies following the process of powder compaction. In particular, the ejector block 9 has a plate substantially parallel to the matrix 2, from which a sub-punch 8 extends at each opening 22 which enters axially into the aforementioned opening 22 and is constrained to the punch 3.

[39] The ejector block 9 may be operated with reciprocating motion in a substantially axial direction to the openings 22 by handling systems known per se, not shown in the figures.

[40] According to the invention, the compaction unit 1 comprises means 70 for detecting the presence of dispersed powders P in the volume between the matrix 2 and or ejector block 9. The detection means 70 comprise checking means 5 for the deposit of said dispersed dust P and signaling means 7 for said presence of dispersed dust P, capable of being activated by said detection means 5. As specified below, the signaling means 7 are capable of blocking the production chain during said process of compacting the powders in the die cavity 30.

[41 ] The checking means 5 preferably consist of a frame 50 which extends at least partially along the perimeter of the openings 22. More precisely, the frame 50 is preferably associated with the matrix 2 by means of a plurality of support members 24 so that it is suitably separated from the lower surface 21 of the matrix 2. The support members 24, for example, consist of respective vertical axis screw members which pass through corresponding holes made on the frame 50 and screw into threaded holes made on the lower surface 21 of the matrix 2. The frame 50 is therefore supported vertically movable below the matrix 2.

[42] In particular, the frame 50 may have a rectangular, triangular or V section.

[43] The signaling means 7 are capable of identifying a possible displacement of the checking means 5 due to the presence of dispersed powders P collected in the space below the matrix 2. The signaling means 7 consist, for example, of a sensor member of a known type, such as for example a proximity sensor or a limit switch sensor. This sensor 7 is constrained to a support member 6, fixed to the lower surface 21 of the matrix 2. The support member 6 is capable of supporting the sensor member in a position substantially coplanar with the frame 50.

[44] The means 70 for detecting the presence of dispersed powders P may be made in different but technically equivalent forms, as described below.

[45] According to a prerogative of the invention, the compaction unit 1 provides for at least one blowing member, positioned in the volume delimited between the matrix 2 and the ejector block 9. In particular, this blowing member is suitable for removing the dispersed powders P accumulated in a channel 90 which separates a pair of sub-punch 8 side by side and positioned on the ejector block 9. This blowing member, not shown in the figures and preferably controlled by a solenoid valve, is suitable for cleaning and removing the dispersed ceramic powders P during the compaction process. This avoids, in use, that an excessive accumulation of dispersed dust P on the surface of the ejector block 9 could lead to damage or breakage of the sub-punch 8 and of the ejector block 9.

[46] The operation of the unit for compacting ceramic powders is easily understood from the above description.

[47] Initially the punch 3 placed inside each opening 22 is arranged at a predetermined height according to the thickness of the ceramic products to be produced, so as to define a cavity 30 open on the upper surface of the matrix 2. The cavity 30 of the die is then filled with the appropriate dose of ceramic powders. The actuation of the press determines, in a known way, the compaction of the ceramic powders inside the cavity.

[48] The lifting of the ejector block 9 is then activated which, by means of the sub-punch 8, raises in turn the punch 3 until it determines the expulsion of the ceramic semi-finished product from the die. In the raised position, the upper surface of the punch 3 is substantially coplanar with the upper surface of the die 2.

[49] During the described steps of the compaction process, in particular during the steps of filling the cavity and moving step, it is possible that a part of the powders is dispersed in the surrounding environment due to the volatility of the powders. In particular, the powders can creep into the clearances between the components of the compaction unit 1 until they reach the volume delimited above by the matrix 2 and below by the ejector block 9. These dispersed powders P may deposit, at least in part, on the surface of the ejector block 9, as visible in Figures 3 and 30.

[50] The signaling means 7 identify the possible movement of the checking means 5, in particular the axial displacement of the frame 50. This possible movement of the checking means 5 is caused by contact with the dispersed powders P which accumulate on the surface of the ejector block 9, as shown in Fig. 3. In practice, the frame 50 moves in contact with the dispersed powders P deposited on the ejector block 9, for example due to the axial movement of the ejector block 9 in the step of ejection of the ceramic semi finished product from the die. This displacement is suitably detected by the signaling means 7. In this case, the signaling means 7 send a signal to a control unit, not shown in the figures, which controls the blocking of the production chain, in particular the operation of the press, so as to prevent damage to the components of the compaction unit.

[51 ] Figures 4 - 6 show a different embodiment of the detection means 70 according to the invention, in which the components already described above are indicated with the same numerical references. According to this solution, the checking means 5 comprise at least a protrusion 51 , for example protruding substantially orthogonally from the frame. Furthermore the protrusion 51 is arranged in front of the signaling means 7.

[52] Conveniently, the signaling means 7 is arranged, through the relative control element support 6, above the ejector block 9, facing the protrusion 51. [53] When the dispersed powders P accumulate, as described in the previous embodiment and move the checking means 5, then the signaling means 7 report the production block, according to the previously described operating mode.

[54] According to a further embodiment shown in Figures 7 - 1 1 , in which the components already described above are indicated by the same numerical references, the signaling means 7 comprise at least one button-sensor device 71 , made for example by a switch, preferably connected to the lower surface 21 of the matrix 2, configured to send the signal of interruption of the production chain when a predetermined pressure is applied there, achieved by the movement of the checking means 5.

[55] According to a further embodiment illustrated in Figures 12 - 14, in which the previously described components are indicated by the same numerical references, the checking means 5 and the signaling means 7 are identified by a checking structure 52 associated with the lower surface 21 of the matrix 2 through a plurality of support members 53. The checking structure 52 is capable to detect ceramic powders in the volume between the matrix 2 and the ejector block 9, identifying the possible displacement of the checking structure 52. The checking structure 52 may be advantageously shaped, so that it extends along the perimeter of the openings 22 of the matrix 2. Furthermore, the checking structure 52 is, for example, made of flexible material such that the powders accumulated on the surface of the ejector block 9 cause the displacement thereof, when contact occurs.

[56] According to another embodiment illustrated in Figures 15 - 19, in which the components already described above are indicated by the same numerical references, each button sensor device 71 is positioned on the surface of the frame 50, to identify, as is the case for the embodiments already illustrated, the deposit of ceramic powders P dispersed during the process.

[57] According to another embodiment illustrated in Figures 20 - 22, in which the components already described above are indicated with the same numerical references, the checking means 5 comprise a plurality of strips 55 which may also act as sensor members. The strips 55 are suitably positioned parallel at the sides of the openings 22. In particular, the strips 55, preferably with a rectangular section, are positioned along the sides of the openings 22 so as to detect the presence of ceramic powders P settled on the surface of the ejector block 9 and which, accumulating, come into contact and consequently move the strips 55. As in the previously illustrated embodiments, from the detection of the movement, the signaling means 7 send a blocking signal to the compaction unit.

[58] According to another embodiment illustrated in Figures 23 - 25, in which the components already described above are indicated by the same numerical references, a plurality of brackets 57 extend in a co-planar way protruding externally with respect to the perimeter delimited by the ejector block 9, so as to overhang a base plate 10 fixed below the ejector block 9. From each bracket 57, a stem 58 having preferably cylindrical shape extends downwards in a substantially orthogonal way. The stem 58 ends at the bottom in a plate 59 substantially coaxial with the stem 58. As in the previous embodiments, when the signaling means 7 identifies the displacement of the checking means 5, caused by the contact between the ceramic powders accumulated on the surface of the base plate 10 and the plate 59, sends the block command of the compaction unit.

[59] According to another embodiment illustrated in Figures 26 - 27, in which the components already described above are indicated by the same numerical references, the detection means 70, for example made as a switch, comprise a plurality of push-button devices sensor 71 , distributed on the lower surface 21 of the matrix 2 peripherally to each opening 22. The sensor-button devices 71 are configured to detect the presence of dispersed ceramic powders P in the volume delimited above by the matrix 2 and below by the ejector block 9. In particular, if the powders P deposited on the ejector block surface 9 apply a pressure on the sensor-button 71 the blocking command of the compaction unit is sent.

[60] According to another embodiment illustrated in Figures 28 - 29, in which the components already described above are indicated by the same numerical references, the aforementioned button-sensor devices 71 are distributed on the upper surface of the ejector block 9, to detect the presence of powders deposited on the surface facing the matrix 2 of the ejector block 9 in the same way as in the previous embodiment.

[61 ] The unit for compacting ceramic products according to the present invention therefore achieves the aim of optimally cleaning the excess ceramic powders dispersed by the compacting and pressing process of the tiles, in particular by ensuring that production is blocked in the event of detected accumulation of powders.

[62] In particular, the compaction unit is able to safely prevent the damage to the dies due to the dispersed powers P. In fact, the signaling means 7 are able to detect the presence of powders near the surface of the checking means 5 and consequently send a signal to the control unit which controls the blocking of the production chain, in particular the operation of the press.

[63] The compaction unit described by way of example is subject to changes according to different needs.

[64] In the practical embodiment of the invention, the materials used, as well as the shape and the dimensions, may be modified depending on requirements.

[65] Should the technical features mentioned in any claim be followed by reference signs, such reference signs were included strictly with the aim of enhancing the understanding of the claims and hence they shall not be deemed restrictive in any manner whatsoever on the scope of each element identified for exemplifying purposes by such reference signs.