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Oven Heat Preservation Process After Refractory Brick Lining Of Glass Melting Furnace
Jan 02, 2019

After the furnace kiln is completed, the next step is the baking process of the furnace. Before the furnace is baked, the heat preservation problem of the furnace cover should be clarified. The furnace cover is cold insulation (referred to as “cold protection”) or hot insulation (the furnace is only baked when it is baked at 1500 °C or above, Thermal protection"). There are still two practices in the industry.

The traditional practice of the industry more than 20 years ago was "thermal protection". When the furnace was baked to above 1450 °C, the insulation was started. This way, it can be seen whether the furnace cover has a "bricking off" phenomenon. Easy to handle. When a large glass factory in Shanghai is roasting kiln, the furnace cover is insulated in the cold state, and only the area of about 1m in the middle of the furnace cover is reserved for the temporary insulation (the insulation after the roasting kiln is finished), and the silicon is covered. The purpose of the aluminum-acid fiber felt is to reduce the temperature difference between the upper and lower ends of the brick body as much as possible and to facilitate inspection. Because in the process of roasting kiln, the crack generated by the thermal expansion of the furnace cover is mainly concentrated in the middle part of the furnace cover. In the process of roasting the kiln, the crack of the furnace cover can be inspected by hooking the aluminum silicate fiber felt with an iron hook. After the kiln is finished, the aluminum silicate fiber felt in the middle part is cleaned, then grouted (or filled with fine quartz sand or siliceous refractory mud), and finally the insulating material in the middle part is smashed.

This practice was also a shock to our traditional thinking and code of conduct. When we visited, we had the confusion of how to do the bricks in the furnace. After the experience, repeated comparisons will eventually lead to their original ideals. After the furnace cover is kept in the cold state, the temperature difference between the inside and the outside of the furnace cover is small, and the upper and lower expansions are uniform, so that it is not easy to cause the brick to fall off the bricks (we think that the brickwork is made by the "beating method". Big is the preconditions). Although the "heat protection" is covered with fiber felt on the furnace cover when baking the kiln, Bijing has a thin insulation, and the temperature difference between the upper and lower sides is very large. Especially after the fiber felt is opened and the furnace cover is removed, the temperature difference between the inside and the outside of the furnace cover is 1000~1200. °C. After the furnace cover insulation layer is completed in this state, the surface temperature of the furnace cover will rise rapidly, and the outer end portion (outer arc line) will have a large expansion amount, while the inner end surface is fully inflated substantially in place, and the outer arc is The amount of expansion should be absorbed by the cracks on the upper end face, but these cracks are filled by quartz sand or siliceous refractory mud. If the top wire is loosened at this time, the cover may form a "lower opening".

If the top wire is not loosened, the lid will rise and form a slight "upper mouth", but it will be covered by the cover and can not be seen. The force of the top wire and the clamp of the entire melting furnace will change greatly. Especially when the furnace cover is insulated, the dome climbing mark has been removed (even if it is not removed, the collision will be displaced and the guidance will be lost). Because there is no pressure to move the hand and other testing equipment, the human feeling is not completely reliable. The force of each part is inconsistent, and the uneven force will generate stress, which has an impact on the life of the brick. In addition, when the "heat protection", the ambient temperature is too high, the hot air and radiant heat on the lid make people feel suffocated, the heat conduction under the feet, the labor insurance shoes are roasted and deformed, the feet are hot and sweaty, and the workers are not on the stove cover. Live, go up and think about it right away, this kind of work environment, the insulation work of the furnace cover is impossible to do very carefully.

Through practical work experience and a large number of case comparisons, the "cold protection" of the furnace cover is better than the "thermal protection", and the probability of problems is even smaller. If there is a fire in the furnace cover, there are quite a few reasons for the bricks before and after the bricks. The mud is not full, and the life is longer. For example, the 115m2 melting furnace cover of a certain enterprise in Sichuan is “cold protection”. It has been used for 13 years, and now it is still very good from the outer surface. Wear fire.


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