Field of the Invention

The present invention relates to furnace firing plates for use in the ceramic industry.

In particular, the present invention relates to furnace firing plates developed for use in the firing process of ceramic products shaped by casting technique and similar techniques and ceramic products that shrink during the firing process.

State of the Art

Ceramic production consists of the following processes; preparation of the raw material that will form the structure, shaping, drying, glazing and firing processes by means of casting, pressure casting, pressing, extrusion etc. methods.

Firing process is carried out by subjecting the particles in contact with each other in the shaped and dried ceramic material to high temperature heat treatment. The porous structure of the ceramic material decreases, its density increases and the material gains strength with the firing process. The firing temperature is kept below the melting point of the material and varies according to the usage rate and content of the material, but it is in the range of 700-1280X3. The firing process is carr ied out in continuous or intermittent furnaces. The products are loaded into the furnace by arranging them on 2-3-storey carts in intermittent furnaces. Refractory firing plates are used so as to load the products into the furnaces.

Refractory firing plates enter the furnace with the product and are exposed to the temperature to which the product is exposed. The refractory material does not shrink with the product and maintains its current form and size while the ceramic product condenses and shrinks in size when it is exposed to heat in the furnace. This causes deformation on the refractory surfaces of ceramic products due to the friction that occurs due to shrinkage during firing. Ceramic manufacturers, who produce the firing plates themselves, perform casting in the form of sand or mud and they cover the surfaces of the plates with refractory materials. However, since these productions are not carried out with standard production processes, problems such as deformities etc. are experienced and wastage is very high. Furthermore, firing plates cast in the form of mud can damage the product during drying and cause more deformation.

Applications encountered in the literature regarding the improvements made in firing plates are presented below so as to prevent deformations in the structures of the firing plates and in the product originating from the plates.

Application numbered US4906509 (A) relates to a two-layer refractory plate. The inventive refractory plate has an embedded granular layer thereon and is durable against cracking. Thermal expansions and cracks in the inventive plate can be prevented and any interaction with the fired product can be prevented.

Application numbered CN110818384 (A) relates to the method of preparing biscuit firing plate. Waste materials such as waste porcelain and purified mud, which are generally produced in the ceramic industry, are added to the plate raw material in the preparation of the inventive firing plate. Here, the minimum amount of waste added to the plate raw material is 25%. The environmental damage of the ceramic production waste is greatly reduced and the production cost of a biscuit firing plate is reduced by mixing the waste with the raw material. Shrinkage is relatively consistent with product shrinkage in the use of the inventive plate in the firing process and thus product bottom surface deformation can be prevented.

As a result, due to the abovementioned disadvantages and the insufficiency of the current solutions regarding the subject matter, a development is required to be made in the relevant technical field.

Brief Description of the Invention

The present invention relates to coated oven firing plates which fulfill the abovementioned requirements, eliminate all disadvantages and bring some additional advantages. The main aim of the invention is to present a furnace firing plate that has to fire shrinkage parallel to the shaped ceramic products and thus prevents possible deformations by shrinking with the product.

One aim of the invention is to provide a furnace firing plate that prevents deformations in the fired product due to frictional stresses.

Another aim of the invention is to provide a furnace firing plate obtained with a standardized production process.

Another aim of the invention is to present a furnace firing plate with a lower cost than the productions carried out by ceramic manufacturers.

The present invention relates to a furnace firing plate with a plate layer made of refractory material so as to fulfill the above mentioned aims. Accordingly said furnace firing plate comprises the following; an upper surface coating made of refractory powder material provided above said plate layer and a lower surface coating made of refractory powder material provided below.

In order to achieve the aims of the invention, said refractory powder is preferably a high- temperature resistant aluminum oxide-containing material.

The present invention also relates to a method of manufacturing a furnace firing plate with a plated layer made of refractory material. Said production method comprises the following process steps; a) grinding the raw material of refractory coating material with the wet grinding process, b) granulation of the ground raw material, c) applying the granulated coating material by pressing to said plate layer surfaces, and d) applying pre-firing process to the coated plate layer

The structural and characteristic features of the present invention will be understood clearly by the following drawings and the detailed description made with reference to these drawings and therefore the evaluation shall be made by taking these figures and the detailed description into consideration.

Figures Clarifying the Invention

Figure 1 is a general view of the inventive oven firing plate.

The figures are not required to be scaled and the details which are not necessary for understanding the present invention may be neglected. Moreover, the elements that are at least substantially identical or have at least substantially identical functions are shown by the same number.

Description of the References

10 Furnace Firing Plate

11 Plate Layer

12 Upper Surface Coating

13 Lower Surface Coating

Detailed Description of the Invention

In this detailed description, the inventive oven firing plate (10) is described only for clarifying the subject matter in a manner such that no limiting effect is created.

The inventive furnace firing plates (10) are the structures used in the firing process of the products shaped in ceramic production and enable the products to be positioned in the furnace. The furnace firing plate (10), whose general view is given with reference to Figure 1 is defined with the following; a plate layer (11) and an upper surface coating (12) provided above said plate layer (11) and a lower surface coating (13) provided below

Furnace firing plates (10) are produced reproducibly under controlled process conditions using special formulas adjusted for firing reduction and refractoriness. The raw material of the coating material used in the said upper surface coating (12) and the lower surface coating (13) is first grinded by the wet grinding process and then granulated The granulated coating material is applied to the plate layer (11 ) surfaces at standard press pressures. The coated plate layer (11 ) is then pre-fired in temperature-controlled furnaces. The volatile organic components in the coating material are burned away from the structure with the pre-firing process and furnace firing plates (10) become more appropriate for use. The (10) firing shrinkage of the furnace firing plates is parallel to the shaped ceramic products, thus the plate and the product shrink together and prevent deformation.

The plate layer (11) in the furnace firing plates (10) is made of refractory material. The coating material applied to the plate layer (11) is also refractory powder material. Said refractory powder is a material containing aluminum oxide that is resistant to high temperatures. The upper surface coating (12) creates an interface between the plate layer (11 ) and the fired product, thus eliminates the frictional stresses that occur during firing in the furnace firing plates (10). Furthermore, the upper surface coating (12) prevents the shaped product from sticking to the furnace firing plate (10) and prevents possible deformations that may occur in the product.

The inventive furnace firing plates (10) are pressed at high press pressures, so their dimensions can be kept within a narrow limit range. Furnace firing plates (10) are subjected to various quality control tests such as fracture strength, etc., during the production process and after production and to usage tests under application conditions. The furnace firing plates (10) are packaged and made ready for use by making a quality control distinction following the completion of the quality control tests. Furnace firing plates (10) are a cost-effective option for users who are trying to produce their own firing plates at high costs and cannot achieve the standardization process.