GB2416767A

GB2416767A - Process and system for the manufacture of ceramic products

Info

Publication number: GB2416767A
Application number: GB0417263A
Authority: GB
Inventors: Stefano Caroni
Original assignee: IMFC LICENSING BV
Current assignee: IMFC LICENSING BV
Priority date: 2004-08-03
Filing date: 2004-08-03
Publication date: 2006-02-08
Also published as: GB0417263D0; CN1772705A

Abstract

A process for the production of ceramic products comprises preparing a layer 4 of at least one ceramic material in a dry powder form or with low humidity, compacting the layer 4 at a pressure between 20 kg/cm<2> and 100 kg/cm<2> and firing the compacted layer. The ceramic materials may comprise a mixture of ceramic materials. The layer 4 may be prepared and compacted on conveying means 1. The compacted layer may be divided into portions 10 of preset dimensions which may be rectangular and have at least two sided which are parallel to each other. The mixture of ceramic materials may comprise illitic and/or kaolin plastic clays, feldspar, sands and vitreous materials. A system for the production of ceramic materials is also disclosed, forming a layer on a resting and conveying means 1 and compacting the layer 4 with compacting means 5 on the resting and conveying means 1 at a pressure between 20 kg/cm<2> and 100 kg/cm<2> and firing means 13. Various mixtures of ceramic materials comprising varying percentages of illitic and/or kaolin plastic clay, feldspar and sands for the production of products having a porosity of between less than 0.5% and 15% are also disclosed.

Description

241 6767

PROCESS AND SYSTEM

The present invention relates to a process for the manufacture of ceramic products.

As is known, the production of ceramic products occurs according to two processes.

A first process provides for the preparation of amalgams of ceramic materials in a plastic state and the extrusion thereof with appropriate extruding machines; the continuous web that is formed is then cut to size to create the products, namely tiles, which are lastly sent for drying and firing in the kilns.

A second process provides for the preparation of ceramic materials in a powder state, the creation of ]5 preset doses of such materials and their loading in moulds of a press, which at each pressing makes the ceramic material cohesive and forms the unfired tiles that, as in the previous case, are then sent for drying and final firing in the kilns.

During the production cycle there are also provided decorative applications which do not however substantially modify the two aforementioned production techniques.

In the second process, when the ceramic materials used are in a powder and dry state, this term referring to materials that have low percentages of humidity and are therefore incoherent, it is indispensable to use the action of a press to give the products the necessary consistency that enables them to be handled before the final firing phase.

The systems that are used to produce ceramic products using ceramic materials in powder and dry form generally have both high acquisition and maintenance costs; such costs increase further due to the required presence of a press that is in itself a very costly component.

The object of the present invention is to improve the

prior art.

s One object of the present invention is to make ceramic products without the need to resort to pressing at high pressures such as supplied using conventional presses, and comprised between 150 and 500 kg/cm2.

I0 A further object of the invention is to create a process for the production of ceramic products that is economically more advantageous, requiring a simplified production system compared with known systems.

IS According to the invention a process is foreseen for the production of ceramic products characterized in that it comprises preparing a mixture of ceramic materials in a dry state or with a low humidity content, depositing said mixture on conveying means having one conveying direction, compacting said mixture on the conveying means, separating portions of compacted mixture, firing said portions.

Further features and advantages of the invention will be more clearly shown by the disclosure of a process 2s for the production of ceramic products feasible with a system shown in the attached drawing in schematic form and from the side.

According to the Figure, a belt conveyor that has an advance direction A is shown with number reference 1.

Above the conveyor 1, near the inlet end 101, there is provided supply means 2 of ceramic materials 3 in powder form, preferably mixed together, which deposits on the conveyor 1 a continuous volume of ceramic materials 3, creating by the movement of the conveyor 1 a substantially continuous web 4.

Downstream of the supply means 2 there is provided compacting means 5 that overlooks and compacts the web 4 during its movement, at preset pressure comprised between 20 kg/cm2 and 100 kg/cm2.

The compacting means 5 comprises a belt 6 wound around roller means 7, respectively drive and driven rollers, and which is parallel to the conveyor 1.

lo The compacting means 5 is provided with a positioning member 8 that acts by vertically shifting an segment T of the belt 6 in relation to the web 4.

The height of the positioner 8 in relation to the web 4 varies according to requirements to obtain preset thicknesses of the web 4 of ceramic materials 3, and according to the features of the latter.

The web 4 downstream of the compacting means 5 has a reduced thickness and is compacted.

Along the conveyor 1 there is also provided a transverse cutting organ 9 of the web 4 that has been compacted according to preset dimensions to give rise to a series of flat products 10 that follow one another.

If required, downstream of the cutting organ 9 stations 11 are arranged and suitable for decorating the top face of each product 10 according to techniques that are known to one skilled in the art.

Lastly, the products 10 are first inserted into a dryer 12 and then into a firing kiln 13, the pressing phase being eliminated.

According to the process for the production of ceramic products, it is possible to obtain products that have at least four different features of porosity by mixing together ceramic materials according to the following examples.

Example 1.

To obtain products 10 having porosity less than or the same as 0.5%, the ceramic materials to be mixed are the following, expressed in the following percentages: illitic and kaolin plastic clays = 45%; feldspar = 39%; lo sands = 8%; vitreous materials = 8%.

Example 2.

To obtain products 10 having porosity comprised between 0.6% and 2.9%, the following ceramic Is materials are mixed expressed in the respective percentages: illitic and kaolin plastic clays = 35%; feldspar = 43%; sands = 20%; vitreous materials = 2%.

Example 3.

To obtain products 10 having porosity comprised between 3% and 6.9%, the following ceramic materials are mixed, expressed in the respective percentages: illitic and kaolin plastic clays = 40%; feldspar = 40%; sands = 20%;

Example 4.

To obtain products 10 having porosity comprised between 7% and 15%, the following ceramic materials are mixed, expressed in the respective percentages: illitic and kaolin plastic clays = 50%; feldspar = 25%; sands = 15%; calcium carbonate, or dolomite, or talc = 10%.

Claims

l) Process for the production of ceramic products characterized in that it comprises: - preparing a layer (4) of at least one ceramic s material in dry powder form or with a low humidity content, - compacting said layer (4) at pressure comprised between 20 kg/cm2 and lOO kg/cm2, - firing said compacted layer (4).
2) Process according to claim l wherein said ceramic material comprises a mixture of ceramic materials.
3) Process according to claim l or 2 wherein said layer (4) is prepared on conveying means (l) having one conveying direction (A).
4) Process according to any preceding claim l to 3 wherein said compacting occurs on said conveying means (l).
5) Process according to any preceding claim l to 4 wherein drying said mixture is provided for between said compacting and said firing.
6) Process according to any preceding claim l to 5 wherein dividing said compacted layer (4) into portions (lO) of preset dimensions is provided for between said compacting and said firing.
7) Process according to claim 6 wherein said portions (lO) are rectangular with at least two sides that are parallel to each other and to said conveying direction (A).
8) Process according to claim l wherein said mixture of ceramic materials comprises: - illitic and/or kaolin plastic clays, - feldspar - sands.
9) Process according to claim 8 wherein for the production of products having porosity less than or the same as 0,5% said mixture comprises further kaolin and vitreous materials.
lO)Process according to claim 8 or 9 wherein said mixture comprises: - 30% to 50% illitic and/or kaolin plastic clays, - 35% to 45% feldspar, - 5% to 10% sands, - 5% to 20% vitreous materials.
ll)Process according to claim 8 wherein for the production of products having porosity comprised between 0.6% and 2.9% said mixture comprises: 30% to 40% illitic and/or kaolin plastic clays, Is - 40% to 50% feldspar, - 5% to 15% sands, - 1% to 3% vitreous materials.
12) Process according to claim 8 wherein for the production of products having porosity comprised between 3% and 6.9% said mixture comprises further kaolin.

13)Process according to claim 8 or 12 wherein said mixture comprises: 35% to 45% illitic and/or kaolin plastic clays, - 35% to 45% feldspar, 15% to 25% sands.

14)Process according to claim 8 wherein for the production of products having porosity comprised between 7% and 15% said mixture further comprises a material selected from calcium carbonate, dolomite, talc.

15)Process according to claim 8 or 14 wherein said mixture comprises: 45% to 55% illitic and/or kaolin plastic clays, - 20% to 30% feldspar, 10% to 20% sands, - 5% to 15% of a material selected from calcium carbonate, dolomite, talc.

16)Mixture of ceramic materials comprising: illitic and/or kaolin plastic clays, feldspar, sands, wherein for the production of products having porosity less than or the same as 0.5% said mixture further comprises vitreous lo materials.

17)Mixture according to claim 16 wherein said mixture comprises: - 30% to 50% illitic and/or kaolin plastic clays, - 35% to 45% feldspar, IS - 5% to 10% sands, - 5% to 20% vitreous materials.

18)Mixture of ceramic materials comprising plastic clays, feldspar, sands, wherein for the production of products having porosity comprised between 0.6% and 2.9% said mixture further comprises kaolin and vitreous materials.

l9)Mixture according to claim 18 wherein said mixture comprises: - 30% to 40% illitic and/or kaolin plastic clays, - 40% to 50% feldspar, - 5% to 15% sands, - 1% to 3% vitreous materials.

20)Mixture of ceramic materials comprising plastic clays, feldspar, sands, wherein for the production of products having porosity comprised between 3% and 6.9% said mixture further comprises kaolin.

21)Mixture according to claim 20 wherein said mixture comprises: - 35% to 45% illitic and/or kaolin plastic clays, - 35% to 45% feldspar, - 15% to 25% sands.

22)Mixture of ceramic materials comprising plastic s clays, feldspar, sands, wherein for the production of products having porosity comprised between 7% and 15% said mixture further comprises a material selected from calcium carbonate, dolomite, talc.

lO 23)Mixture according to claim 22 wherein said mixture comprises: - 45% to 55% illitic and/or kaolin plastic clays, - 20% to 30% feldspar, - 10% to 20% sands, Is - 5% to 15% calcium carbonate, or dolomite or talc.

24)System for the production of ceramic products characterized in that it comprises: - resting and conveying surface (1), - ceramic material supplying means (2) with at least one component and in powder on said resting and conveying surface (1), in the form of a layer (4), compacting means (5) of said layer (4) on said resting and conveying surface with pressure comprised between 20 kg/cm2 and 100 kg/cm2, - firing means (13) of said compacted layer (4).

25)System according to claim 24 wherein said resting and conveying surface (1) and compacting means (5) are both movable in a common movement direction (A) and with speeds synchronized between said supplying means (2) and said firing means (13).

26)System according to claim 24 or 25 wherein between said compacting means (5) and firing means (13) drying means (12) of said compacted layer (4) is provided for.

s 27)A process substantially in accordance with any example hereinbefore described with reference to the accompanying drawing.

28)A system substantially as hereinbefore described with reference to the accompanying drawing.