Title of Invention

METHOD AND PLANT FOR FORMING CERAMIC SLABS OR TILES

Abstract A method and plant for forming ceramic tiles or slabs are disclosed. The method involves depositing on a conveyor belt (2) a continuous layer of powders (100), pressing said powders to obtain a coherent article of compacted powders by advancing said belt (2) through a pressing station (3) of continuous type, and controlling the force exerted on the powders (100) during pressing, using plate means (16, 35). The plant (1) for forming ceramic tiles or slabs comprises a conveyor belt (2) on which a continuous strip of material in powder form is created and which is arranged to advance said strip through a continuous pressing station (3) which enables the powder strip on said belt to be compacted to obtain a coherent article of compacted powders, means (60) being associated with said pressing station to laterally retain the material on said belt, wherein said pressing station (3) is provided with plate means (16, 35) for controlling the force exerted on said powders.
Full Text TECHNICAL FIELD
The present invention relates generally to a method for manufacturing
ceramic tiles or slabs, and in. particular to a method for forming said slabs
and the relative plant for its implementation.
BACKGROUND ART
Ceramic tile forming methods are known consisting of depositing a
continuous layer of powders on a flexible belt with which walls are
associated to laterally retain the powders. The belt on which said layer of
powders is created is then advanced through a pressing station of
continuous type, which compacts the powders on the flexible belt to obtain
a coherent article of compacted powders. On termination of compacting,
the article is divided into blanks, and possibly subjected to a second
pressing. This method is described in detail in patent application No.

RE2002A000035 in the name of the same applicant, to the text of which
reference should be made for more complete information.
According to the known art described in said patent application, the
pressing station generally comprises both powder compacting means, in
the form of rollers or compacting belts, and means for controlling the
expansion of the material on termination of compacting. In both cases,
said compacting means and said expansion control means are adjustable
in height to enable the thickness of the article to be varied.

The height adjustment of the compacting means ensures planarity of the
article, and a constant compacting ratio in the transverse direction, but
gives no assurance with regard to the mechanical characteristics of the
article, which are a function of the maximum pressure with which the
compacting means act on the powders.
In this respect, it can happen that the thickness of the strip of powders
deposited on the belt varies both in the transverse direction and in the
longitudinal direction either for aesthetic reasons or because of loading
defects, or that for the same thickness the powders have a particle size
distribution or other physical characteristics different in the transverse
direction and hence are compacted to a different extent in the transverse
direction.
All this means that the mechanical characteristics of the compacted article
can vary both in the transverse and in the longitudinal direction until such
values are achieved as not to guarantee the mechanical coherence of the
article, which hence cracks and crumbles, becoming unusable.

For example, European Patent No. 1226927 discloses a first belt that
cooperates with a second belt to compress the powders. However, in EP
1226917 the compression is not controlled but depends only on the
relative inclination of the belts so that there is no guarantee on the
mechanical characteristics of the finished article which are a function of
the maximum pressure with which the compacting means act on the
powders.
European Patent No. 1211034 shows a charging device for ceramic
powders that, in order to create some aesthetical effects, uses a conveyor
belt having ridges in various configurations.
The object of the present invention is to overcome the drawbacks of the
known art within the framework of a simple and rational solution.
DISCLOSURE OF THE INVENTION
The invention attains said object by providing a method for forming
ceramic tiles or slabs in which the force exerted on the powder strip is
regulated during pressing.
Specifically, the method of the invention comprises at least the following
operative steps:

- depositing on a conveyor belt a continuous layer of powders, wails being
associated with the belt for their lateral retention;
- pressing said powders to obtain a coherent article of compacted powders
by advancing said belt through a pressing station of continuous type;
- controlling the force exerted on the powders during pressing.
According to a preferred embodiment of the aforesaid method, the powder
pressing step comprises both compacting said powders and controlling the
expansion of said powders after compacting. According to the invention
the force exerted on said powders during pressing can be controlled either
during powder compacting alone or during powder expansion control
alone or during both.
It should also be noted that the plant of the invention can be used both for
obtaining a completely compacted article, and for obtaining a pre-
compacted article which must then be subjected to a second pressing.
The invention also includes a plant for implementing the aforesaid method.
This plant comprises a conveyor belt on which a continuous strip of
material in powder form is created and which is arranged to advance said
strip through a pressing station provided with means for laterally retaining
the material on said belt, means being associated with said pressing
station to control the force exerted on said powders.
According to the invention said pressing station comprises compacting
means enabling the powders to be continuously compacted on the belt
advancing through the station, with which said compaction control means
are associated.
Said continuous compacting means can be either in the form of a
compacting roller or in the form of a compacting belt.

According to a preferred variant of the invention, said pressing station also
comprises, downstream of said continuous compacting means, a device
for controlling the expansion of the material after compaction.
The means for controlling the force exerted on the powders comprises a
control unit for at least one hydraulic cylinder-piston unit with which the
powder compaction means or said device for controlling material
expansion after compaction are associated.
In a variant of the invention, said expansion means comprise a flexible
plate, with which a plurality of hydraulic cylinder-piston units controlled by
said control unit are associated. According to the invention said hydraulic
cylinder-piston units can be disposed in several parallel rows to enable the
force exerted on the powders to be also controlled along the powder
advancement direction.
Further characteristics of the invention are defined in the claims.
To better understand the operative modalities of the method of the
invention and the constructional characteristics and merits of the relative
means for its implementation, reference is made hereinafter to the figures
of the accompanying drawings which show by way of example a particular
preferred embodiment of the plant for implementing the aforedescribed
method.
Figure 1 is a schematic side section through the plant of the invention.
Figure 2 is an enlarged view of a detail of the invention.
Figure 3 is the section Ill-Ill of Figure 1.
Figure 4 is the section IV-IV of Figure 2.
Figure 5 is an enlarged view of a detail of a variant of the invention.
Figure 6 is a schematic cross-section through Figure 5.

Figure 7 shows an enlarged detail of Figure 6.
Said figures show the plant 1, which comprises a motorized lower
conveyor belt 2 on which a continuous strip 100 of powders is deposited
by usual devices of known type, and hence not shown.
The belt passes through a pressing station 3, the purpose of which is to
compact the powders of the strip 100 to obtain an article, of substantially
parallelepiped form, of coherent material.
According to the degree of pressing to which the powders on the belt are
subjected, the article can form the final tile, or a pre-compacted slab which
must then be subjected to a second pressing.
The article can be decorated if required and then divided into blanks of
suitable dimensions depending on the final product size to be obtained.
The pressing station 3 comprises a powder compaction first zone 30,
downstream of which there is a second zone 31 in which the article formed
in the compaction zone 30 is decompressed.
The powder compaction zone 30 comprises two mutually superposed
motorized compactor devices 4 and 5, one of which is positioned below
the belt 2 and the other above it at a distance from the belt 2 which can be
adjusted on the basis of the thickness of the powder strip to be compacted
and of the pressure at which pressing is to be carried out.
Each of the compactors 4 and 5 is provided with a motorized roller and an
idle roller, indicated respectively by the reference numerals 40,41 and 50,
51, about which there passes a respective band 42, 52. Between each
pair of rollers 40,41 and 50, 51 there is positioned a roller table 43 and 53,
consisting of a plurality of idle rollers, the purpose of which is to maintain
the bands 42 and 52 pressed to compact the strip of powder material. In

the illustrated embodiment the roller table 53 is inclined in the direction of
advancement of the belt 2 so as to make the compaction of the strip
powders gradual.
Downstream of the roller tables 43 and 53 there are provided two
opposing rollers 6 and 7, of which the roller 6 is positioned below the band
42, whereas the roller 7 is positioned above the band 43 and presses this
latter against the powder strip 100 advancing on the belt 2.
With reference to Figure 4 it can be seen that the roller 7 is associated
with two hydraulic cylinder-piston units 8 and 9 supported by a frame 10
and arranged to transmit a controlled force to the roller 7, in order to
regulate the pressure which said roller exerts on the powder strip 100. For
this purpose the cylinder-piston units 8 and 9 are connected by a hydraulic
circuit 11 to a control unit 12 comprising a pump 13 for delivering a fluid,
typically oil, under pressure, a pressure regulating valve 14 provided with
a pressure transducer in feedback, and a pressure gauge 15 measuring
the pressure in the feed circuit of the cylinder-piston units.
The roller 7 separates the compaction zone 30 for the powder strip 100
from the subsequent decompression zone 31 in which the powder strip
100 expands in a controlled manner to prevent cracks arising in the
compacted article.
In the illustrated embodiment {Figures 2 and 3) said decompression zone
31 comprises two superposed plates 16 and 17, of which the lower plate
17 is positioned below the belt 2 and the upper plate 16 is positioned
above the belt 2, in contact with the band 52. The lower plate 17 is fixed
and horizontal, whereas the plate 16 is supported on a crosspiece 18 by

hydraulic cylinder-piston units 19 which enable the force exerted on the
powders by the plate to be regulated.
As can be seen from the figures the plate 16 can also swivel about the
cylinder-piston units so that it can be inclined to the belt 2 to enable the
compacted strip of powders to expand with a very small deformation
gradient compatible with the intrinsic characteristics of the powders.
The cylinder-piston units 19 are connected by a hydraulic circuit 21 to a
control unit 20 identical with the control unit 12 shown in Figure 4.
The pressing station also comprises lateral powder retention means,
which in the illustrated embodiment are in the form of two parallel
deformable straps 60 associated with the compactor device 5.
In this respect, each of the two straps passes partially about the
compactor device 5 and about deviator wheels 101,102 and 103. It
should be noted that the. deviator wheels are of adjustable distance apart,
in order to be able to vary the dimension of the strip of compacted
powders in the direction perpendicular to the direction of advancement of
the belt in accordance with the format to be obtained.
According to a variant of the invention illustrated in Figures 5,6 and 7, the
decompression zone 31 comprises a fixed body 32 supporting a flexible
plate 35 via a plurality of hydraulic cylinder-piston units 36.
In detail, each cylinder-piston unit comprises a cylinder, consisting of a
cavity 320 present in the body 32, within which there slides a piston 321
the base of which is fixed to the flexible plate 35. The plate 35 is fixed by
screws 37, each of which is received in a socket piece 38 inserted into a
hole 39 in the plate 35. As can be seen from the figure, the socket piece
38 is substantially smaller than the hole 39, so that the plate can undergo

small swivel movements relative to the support body 32. In practice the
plane in which the plate lies during plant operation depends on the
inclination of the band 52.
All the cavities 320 are connected to a hydraulic circuit 49 connected to a
control unit 20.
From the aforegoing description it is apparent that, advantageously, the
plate 35 behaves as an isostatic buffer, to distribute the force uniformly
over the powders both in the transverse direction and in the longitudinal
direction.


WE CLAIM :
1. A method for forming ceramic tiles using ceramic powders
materials, characterized in that it comprises the following operative steps:
a. depositing on a conveyor belt (2) a continuous layer of powders
(100), means (60) being associated with the belt (2) for lateral retention of
the powders,
b. pressing said powders to obtain a coherent article of compacted
powders by advancing said belt (2) through a pressing station (3) of
continuous type,
c. controlling the force exerted on the powders (100) during
pressing, using plate means (16, 35).
2. A method as claimed in claim 1, wherein the pressing of said
powders (100) comprises both the compaction of said powders (100) and
the controlled expansion of said powders (100) after compaction.
3. A method as claimed in claim 2, wherein the control of the force
exerted on the powders (100) during pressing is associated with the
powder compaction step.
4. A method as claimed in claim 2, wherein the control of the force
exerted on the powders during pressing is associated with the powder
expansion step.
5. A method as claimed in claim 2, wherein the control of the force
exerted on the powders during pressing is associated both with the
powder compaction step and with the powder expansion step.

6. A method as claimed in claim 1, wherein the powder compaction in
the pressing station is progressive in the powder advancement direction.
7. A method as claimed in claim 1, wherein the article or the blanks
obtained therefrom are subjected to a second pressing.
8. A method as claimed in claim 1, wherein the material expansion
control takes place at least in the direction perpendicular to that article
surface of greatest dimensions.
9. A plant (1) for forming ceramic tiles or slabs using ceramic powders
materials, comprising a conveyor belt (2) on which a continuous strip of
material in powder form is created and which is arranged to advance said
strip through a continuous pressing station (3) which enables the powder
strip on said belt to be compacted to obtain a coherent article of
compacted powders, means (60) being associated with said pressing
station to laterally retain the material on said belt, characterised in that
said pressing station (3) is provided with plate means (16, 35) for
controlling the force exerted on said powders.
10. A plant as claimed in claim 9, wherein said pressing station (3)
comprises a first zone in which the powders (100) are compacted and a
second zone in which the powders (100) are decompressed.

11. A plant as claimed in claim 9, wherein said means for controlling the
force exerted on the powders (100) are associated with said first
compaction zone.
12. A plant as claimed in claim 9, wherein said means for controlling the
force exerted on the powders (100) are associated with said second
powder decompression zone.
13. A plant as claimed in claim 9, wherein said means for controlling the
force exerted on the powders are associated both with said first
compaction zone and with said second powder decompression zone.
14. A plant as claimed in claim 9, wherein said means for controlling the
force exerted on the powders comprise a unit (12) for controlling at least
one hydraulic cylinder-piston unit (8) with which said powder compaction
means are associated.
15. A plant as claimed in claim 9, wherein said compaction means
comprise at least one compactor roller.
16. A plant as claimed in claim 9, wherein said means for controlling the
force exerted on the powders comprise a unit for controlling at least one
hydraulic cylinder-piston unit with which said device for controlling the
expansion of the compacted powders is associated.
17. A plant as claimed in claim 16, wherein said device for controlling
powder expansion comprises at least one plate (17).

18. A plant as claimed in claim 16, wherein said device for controlling
the expansion of the compacted powders comprises a plate (17)
associated with a plurality of parallel hydraulic cylinder-piston units (19)
disposed in several rows.
19. A plant as claimed in claims 14 and 16, wherein said control unit
(12) for at least one cylinder-piston unit comprises at least one pump (13)
for delivering a pressurized fluid, and a valve (14) for regulating the
pressure of said fluid.


A method and plant for forming ceramic tiles or slabs are disclosed.
The method involves depositing on a conveyor belt (2) a continuous layer
of powders (100), pressing said powders to obtain a coherent article of
compacted powders by advancing said belt (2) through a pressing station
(3) of continuous type, and controlling the force exerted on the powders
(100) during pressing, using plate means (16, 35).
The plant (1) for forming ceramic tiles or slabs comprises a
conveyor belt (2) on which a continuous strip of material in powder form is
created and which is arranged to advance said strip through a continuous
pressing station (3) which enables the powder strip on said belt to be
compacted to obtain a coherent article of compacted powders, means (60)
being associated with said pressing station to laterally retain the material
on said belt, wherein said pressing station (3) is provided with plate means
(16, 35) for controlling the force exerted on said powders.

Documents:

01069-kolnp-2005-abstract.pdf

01069-kolnp-2005-claims.pdf

01069-kolnp-2005-description complete.pdf

01069-kolnp-2005-drawings.pdf

01069-kolnp-2005-form 1.pdf

01069-kolnp-2005-form 3.pdf

01069-kolnp-2005-form 5.pdf

01069-kolnp-2005-international publication.pdf

1069-KOLNP-2005-(12-10-2011)-CORRESPONDENCE.pdf

1069-KOLNP-2005-(12-10-2011)-FORM 3.pdf

1069-KOLNP-2005-ABSTRACT 1.1.pdf

1069-KOLNP-2005-ABSTRACT.pdf

1069-KOLNP-2005-AMANDED CLAIMS 1.1.pdf

1069-KOLNP-2005-AMANDED CLAIMS.pdf

1069-KOLNP-2005-AMANDED PAGES OF SPECIFICATION.pdf

1069-kolnp-2005-assignment.pdf

1069-KOLNP-2005-CANCELLED PAGES.pdf

1069-KOLNP-2005-CORRESPONDENCE 1.1.pdf

1069-KOLNP-2005-CORRESPONDENCE.pdf

1069-kolnp-2005-correspondence1.2.pdf

1069-KOLNP-2005-DESCRIPTION (COMPLETE) 1.1.pdf

1069-KOLNP-2005-DESCRIPTION (COMPLETE).pdf

1069-KOLNP-2005-DRAWINGS 1.1.pdf

1069-KOLNP-2005-DRAWINGS.pdf

1069-kolnp-2005-examination report.pdf

1069-KOLNP-2005-FORM 1 1.1.pdf

1069-KOLNP-2005-FORM 1-1.2.pdf

1069-KOLNP-2005-FORM 1-1.3.pdf

1069-KOLNP-2005-FORM 1.pdf

1069-kolnp-2005-form 18.pdf

1069-KOLNP-2005-FORM 2 1.1.pdf

1069-KOLNP-2005-FORM 2.pdf

1069-KOLNP-2005-FORM 3 1.1.pdf

1069-kolnp-2005-form 3.2.pdf

1069-KOLNP-2005-FORM 3.pdf

1069-kolnp-2005-form 5.pdf

1069-KOLNP-2005-FORM-27.pdf

1069-kolnp-2005-gpa.pdf

1069-kolnp-2005-granted-abstract.pdf

1069-kolnp-2005-granted-claims.pdf

1069-kolnp-2005-granted-description (complete).pdf

1069-kolnp-2005-granted-drawings.pdf

1069-kolnp-2005-granted-form 1.pdf

1069-kolnp-2005-granted-form 2.pdf

1069-kolnp-2005-granted-specification.pdf

1069-KOLNP-2005-OTHERS PCT FORM.pdf

1069-kolnp-2005-others.pdf

1069-KOLNP-2005-PETITION UNDER RULE 137.pdf

1069-KOLNP-2005-REPLY TO EXAMINATION REPORT 1.1.pdf

1069-KOLNP-2005-REPLY TO EXAMINATION REPORT.pdf

1069-kolnp-2005-reply to examination report1.2.pdf

abstract-01069-kolnp-2005.jpg


Patent Number 248886
Indian Patent Application Number 1069/KOLNP/2005
PG Journal Number 36/2011
Publication Date 09-Sep-2011
Grant Date 05-Sep-2011
Date of Filing 03-Jun-2005
Name of Patentee SACMI COOPERATIVA MECCANICI IMOLA SOCIETA' COOPERATIVA
Applicant Address 17/A, VIA SELICE PROVINCIALE, I-40026 IMOLA
Inventors:
# Inventor's Name Inventor's Address
1 COCQUIO ALESSANDRO VIA FONTANA DI RIATTI, 17, I-47100 FORLI, ITALY
2 RIVOLA, PIETRO VIA C. BARUZZI, 3, I-40026 IMOLA
PCT International Classification Number B28B 5/04
PCT International Application Number PCT/EP2003/014875
PCT International Filing date 2003-12-23
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 RE2003A000004 2003-01-20 Italy