Whether the design of the kiln is reasonable and perfect, it directly restricts the investors and also restricts the quality of the kiln. Through lots of comparisons between different production lines, we found that the same type of raw materials and the same type of kilns may have different results due to the design factors.
The key lies in the following points:
First of all, determine the relations of ‘four sections’ (drying, preheating, burning and cooling). The “Four sections” relationships could not be determined according to the conventional phenomenon. It is necessary to grasp the differences of raw materials, adjust measures to local conditions, adapt to the characteristics of the raw materials, design and formulate the length and size of the burning section. The design size of the kilns should not be too conservative. In the aspect of functional usability in structure, it should be reasonably configured and strictly controlled in case of the technology is too complicated. The fired brick is different with other fired products. Firing range, product stability, quenching and heating range is slightly wider than other industry products and it will be fine to meet the needs of itself. In the aspect of design and material selection, we should pay attention to the applicability. The life of a kiln depends largely on the materials used, while kiln materials are directly related to investment. How to deal with these two relations are the most difficult for investors. On one hand, good quality is needed, and on one another hand, less investment is better. So, it is more difficult to make a reasonable materials selection scheme. For example, one factory in Northeast China selects concrete products for sand sealing during design, while another factory in South China selects steel products for sand sealing during design. Intuitively, people would think that the investment of concrete products is smaller than that of steel, but in the actual application process, things are totally different. The concrete sand sealing is easy to be damaged during the operation of the kiln, which leads to the kiln stop working and the cost of shutdown and maintenance increases, but the steel structure sand sealing is not likely to be damaged. So, during design stage, both of the investment cost and production cost should be considered, and we mustn’t consider saving investment cost alone. In terms of structure selection, there are also measures to save money. For example, for the local structure below the probe brick of the sintered brick tunnel kiln, the selection of materials should not be uniform, including the selection of materials in different temperature zones should be treated differently: those that can adapt to the standard type should not choose the special type; those can adapt to the ordinary type, cannot choose high-grade; those can adapt to ordinary clay bricks, cannot choose high alumina refractory brick; those that can be purchased nearby should not be purchased far away.
In the past, we found that the design and material selection of many kilns were not standardized according to different regions, which virtually increased the investment. In this case, in order to save investment, efforts should be made to reduce unnecessary investment waste. For the sake of investors, on other structural materials selection, such as kiln roof, kiln wall, heat preservation, heat insulation, fire resistance, steel structure and so on, the adaptability and application should be the base of reasonable use.