More specifically, this invention relates to a support to be used in the production of articles of ceramic sanitaryware to enable each article to be transferred from the demoulding station to the glazing station without further handling and without having to change the support.

In the method according to the invention, all the steps in the production of an article of sanitaryware, from the step of demoulding the article to the step of glazing it and excluding only the subsequent firing step, are carried out without the article having to be handled by an operator or transferred by mechanical devices of any kind.

The invention also relates to the use of a support for each step in the production of sanitaryware, from demoulding to glazing.

Background Art Figure 1 schematically indicates the different steps in the production of sanitaryware according to the current state of the art: after mixing the raw materials in suitable proportions, water and deflocculants are added to produce a pourable ceramic mixture known as"slip"to experts in the trade.

The slip is cast into a mould in a customary manner to form an article of sanitaryware.

Next, the article is removed from the mould-this step being known as demoulding-and is transferred to a first support which may be defined as demoulding support, hereinafter referred to as support type"A", and which depends on the type of sanitaryware being made and on the moulding technology used.

Usually, this support may be kept in the subsequent"green"finishing step, when the article is still in the green state, that is to say, when it is capable of supporting itself but is still very wet.

In some cases, before the"green"finishing step, it may be necessary to transfer the article to a different type of support, hereinafter referred to as support type"B", because the support type "A"does not allow the water content of the previously demoulded article to be brought down to the required level.

The support type"B"is designed to resist the higher temperatures required for the subsequent production steps which include pre-drying in air and another finishing step when the article is said to be in the"leather hard"state.

"Green"finishing, pre-drying in air and finishing in"leather hard"state form part of a first finishing process.

This is followed by another, forced drying step at a temperature of around 80-90 degrees.

The customary supports, types"A"and"B", are made of plaster and/or polyurethane and must be able to support the semifinished article of sanitaryware for several hours during the production process, from the demoulding step to the drying step.

The support must adequately support the weight of the article of sanitaryware when it is still in the green state. Further, the support must allow for the shrinkage which the article undergoes as a result of changes in its physical properties, mainly changes in humidity and temperature when it is dried in air.

On completion of these steps, the article of sanitaryware is transferred to other supports, made of metal, that may be wheel mounted (in which case they are known as trolleys) or fixed shelvings.

During transfer from one support to another, there is a high risk of damaging or permanently deforming the sanitaryware, which is not yet completely dry (green or raw state).

This risk is augmented by the fact that these operations are normally carried out manually and that the sanitaryware, particularly when in the green state, may be extremely heavy on account of the large amount of water it still contains.

For this reason, transfer must be carried out with great care and is an exhausting and time- consuming task.

Disclosure of the invention The present invention therefore has for an object to provide an improved type of support for articles of sanitaryware enabling such articles to remain on the same support from the demoulding station to the glazing station without further handling and without having to be transferred from one type of support to another.

According to one aspect of it, the present invention provides a support for articles of sanitaryware as defined in claim 1.

Another object of the present invention is to provide an improved method for making articles of sanitaryware wherein all the steps in the production of an article of sanitaryware, from the step of demoulding the article to the step of glazing it, are carried out without the article having to be handled or transferred from one support to another by an operator and/or by mechanical devices of any kind.

According to another aspect of it, the present invention provides a method for making sanitaryware as defined in claim 16.

According to yet another aspect of it, the invention also relates to the use of a support for each step in the production of sanitaryware, from the demoulding step to the end of the glazing step, as defined in claim 18.

The dependent claims describe preferred and/or advantageous embodiments of the invention.

Description of the drawings The preferred embodiments of the invention will now be described, without restricting the scope of the inventive concept, with reference to the accompanying drawings in which : Figure 1 is a block diagram representing the initial steps of moulding an article of sanitaryware according to prior art; Figures 2 to 10 illustrate the new type of supports according to the present invention.

Detailed description of the preferred embodiments of the invention According to the current state of the art, traditional supports of type"A"for different kinds of sanitaryware may be made of plaster or high-density polyurethane foam, hereinafter referred to simply as polyurethane.

Traditional supports have specific geometric characteristics enabling them to support the weight of the sanitaryware while allowing for the shrinkage of each article.

Figures 2 to 10 illustrate supports of the new type, designed to replace traditional supports types"A"and"B".

The new supports illustrated in the drawings are, respectively, the following: a support 1 for a first type of flush tank (Figure 2) to be used, if necessary, in combination with the support 2 of Figure 3 (depending on the shape of the article to be made); a support 3 for a second type of flush tank (Figure 4); a support 4 for a washbasin stand (Figure 5) ; a support 5 for a washbasin (Figure 6); a support 6 for a shower tray (Figure 7); a support 7 on which a toilet bowl can rest on the mouth of the bowl (Figure 8); a support 8 (Figure 9) in two parts on which a toilet bowl can rest on its stand in combination with the support 9 of Figure 10.

Thanks to their improved mechanical properties, the new supports 1 to 9 illustrated in Figures 2 to 10 are better able to withstand the forces generated during the production process, from the demoulding step to the drying step.

The new supports must also withstand large variations in temperature and ambient conditions.

For this reason, the new supports must be made of materials which will allow water remaining in the sanitaryware to be removed and which at the same time possess high mechanical strength, heat resistance and good resistance to chemical attack by the weakly alkaline solutions present in the ceramic mixture.

To obtain these properties, the supports are made of special organic or inorganic compounds: the organic compounds are plastic based, open-pore materials, while the inorganic compounds are porous, ceramic aluminosilicate materials.

The base plastic used for the production of the porous material may be derived from one or more resins or thermosetting monomers or derivatives thereof.

For example, the following may be used: polyester resins, acrylic monomers, epoxy resins, resin polymers and copolymers and thermosetting monomers.

The base plastic used for the production of the porous material may also be derived from one or more substances selected from the thermoplastic polymer and copolymer group, such as, for example, polyolefins.

The processes for making the porous materials from plastic may be any of the following: hot pressing of fine pellets of thermoplastic polymers and/or copolymers; cold pressing of mixtures obtained from inorganic and/or organic charges bonded with thermosetting resins; catalysed setting of castings made from oil-water emulsions containing thermosetting resins and/or monomers with or without charges of inorganic and/or organic powders.

The plastic based porous materials made using the above processes have the following properties: average pore diameter up to 50 lim or, more specifically, from 0. 5, um to 50 um ; total open porosity up to 50% or, more specifically, from 10% to 50%; flexural strength up to 100 N/mm2 or, more specifically, from 5 N/mm2 to 100 N/mm2 ; Vicat softening temperature: at least 60°C (degrees centigrade).

The Vicat softening temperature is a measure of the temperature at which a plastic starts to soften under certain test conditions, defined in ISO 306.

It is measured using a standard penetrator (a flat-ended needle with a circular section of 1 mm2) which penetrates a test specimen under a define load.

The temperature at which the needle penetrates to a depth of 1 mm is called VST and is expressed in °C (degrees centigrade).

This type of test indicates the capacity of the material to resist limited contact with a heated object for a short length of time.

The term"plastic based porous materials"may indicate materials with capillary porosity or materials with non-capillary porosity.

Examples of these types of material and of their production process are described in patent EP-0 516 224 B 1 which is incorporated herein by reference.

As regards the inorganic materials used to make the supports, these are mainly porous ceramic products such as, for example: once-fired surfacing material;

white or red biscuit, that is to say, ceramic material that has been fired twice; whiteware for crockery or cordierite based refractories.

More specifically, ceramic aluminosilicates such as refractories, whiteware for crockery, once-fired porous ceramic surfacing material and surfacing biscuit may be used.

As regards whiteware for crockery, the chemical composition comprises as the main components silicon oxide (SiO2), in a percentage range by weight of 40% to 80%, and alumina (A1203), in a percentage range by weight of 13% to 20%. Other components that may be present in smaller quantities are oxides of iron, titanium, calcium, magnesium, potassium and sodium.

The chemical composition of once-fired porous ceramic surfacing material and of surfacing biscuit also comprises as the main components silicon oxide (SiO2), in a percentage range by weight of 50% to 75%, alumina (A1203), in a percentage range by weight of 13% to 20%, and calcium oxide (CaO) in a smaller percentage range by weight of 3% to 20%.

In this case, too, other components may be present in small quantities. For example, these may include: oxides of iron, titanium, calcium, magnesium, potassium and sodium.

Table 1 below shows the ranges of the components of whiteware for crockery, once-fired porous surfacing material and surfacing biscuit used to make the ceramic supports according to the invention.

Table 1-Chemical composition ranges of porous ceramic materials for supports Oxides Unit of Whiteware for crockery Once-fired porous surfacing Measure material and surfacing biscuit (mass) SiO2 % 40-80 50-75 A1203 % 13-20 13-20 Fe203 % 0-8 0-8 TiO2 % 0-1 0-2 Ca0 % 0-30 3-20 Ego % 0-15 0-5 K20 % 0-4 0-5 Na2O 0-4 0-5 Table 2 below shows some examples of preferred composition of porous ceramic materials for the supports according to the invention.

Table 2-Preferred composition of porous ceramic materials used to make the supports Oxides Unit of Whiteware for crockery Once-fired porous surfacing Measure material and surfacing biscuit (mass) SiO2 % 61 59 A1203 % 16 15 Fie203 0. 5 TiO2 % 0. 5 0. 5 CaO % 15 18 MgO% 23 K2O % 2.5 3 Na2O % 2. 0 1

Table 3 compares the main chemical and physical properties of the materials used for the new supports made of aluminosilicates and plastic resins, and those for traditional supports (plaster and polyurethane).

Table 3-Comparison of chemical and physical properties of the materials used for the supports Polyurethane Unit Once- Once-. Once- measure Refrac-fired ,. biscuit wareior tories porous r'crockery surfacing material Flexural N/10-30 strength um2 Heat °C 1. 000- 50 60-80 resis-2. 500 tance Total % 10-50 0 open porosity Average llm diameter of pores Chemical High High High High High Low High resistance to weakly alkaline saline solutions

The invention also concerns a method for making sanitaryware comprising the following steps: casting a ceramic mixture (slip) into a mould to form an article of sanitaryware; removing the article of sanitaryware from the mould and transferring it to a support; first finishing, comprising the sub-steps of"green"finishing, that is to say, the finishing that is performed when the article of sanitaryware is still very wet, natural pre-drying in air and "leather"finishing performed on the article once it has been pre-dried in air to"leather hard"state; forced drying at a temperature of around 80-90 degrees centigrade; second finishing, known as"white"finishing, performed on the dry article; inspection and glazing.

All the above mentioned steps are performed without transferring the article of sanitaryware from one support to another, thanks to the constructional features of the supports made according to the invention which are able to meet all the requirements of each step in the production process without being changed.

The supports according to the invention offer significant advantages for the management of sanitaryware in the semifinished state during the central stages of the production process from casting to glazing.

Indeed, using the supports according to the invention makes it possible to increase the level of automation of the production process, reducing the human labour requirement and the number of times each article of sanitaryware has to be handled: this permits a general improvement in sanitaryware quality and, at the same time, reduces waste.

Table 4 summarises the production parameters and the advantages of the new supports compared to traditional supports.

Table 4-Summary of advantages obtainable by the use of new supports in the production process Type of support New Traditional Resin/ceramic Plaster Polyurethane Production parameters materials Elimination of need to Yes No No transfer semi-finished products Single support Yes No No Possibility of automation High Low Medium Labour intensiveness Low High Medium

The invention as described above may be modified and adapted in several ways without thereby departing from the scope of the inventive concept as defined in the claims. Moreover, all the details of the invention may be substituted by technically equivalent elements.