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Cooling Method of Graphitization Furnace

When the graphitization furnace is in operation, the furnace temperature is above 2300℃, and the end connecting the conductive electrode and the furnace core is working at such a high temperature. The other end of the conductive electrode is connected to the copper bus bar. This must ensure that the temperature of the connection with the copper plate is lower than the melting temperature of the copper plate. At the same time, because the conductive electrode is exposed in the air, it must work at a temperature lower than the oxidation temperature. For this reason, forced cooling must be performed. There are basically two cooling methods.

1. Direct Water Spray Cooling

Use a drilled water pipe to horizontally support the conductive electrode, and water the conductive electrode and its connection with the copper bus bar to cool it. This direct cooling method is simple, convenient, and has a good cooling effect. The disadvantage is that the cooling water splashes everywhere and it is easy to seep into the furnace body. Moreover, this method requires the installation of a drain tank. The tank is easy to block, and if it is not treated in time, the water in the tank will easily penetrate into the furnace, and the spray water will easily penetrate into the furnace, shortening the life cycle of the furnace, and at the same time, it is easy to oxidize the products in the furnace. . In addition, in the north, it is easy to freeze around the water tank in winter, which is difficult to handle.

2. Direct Internal Cooling

After the conductive electrode is bored, it is directly plugged with a wire, and then two long and one short water pipes are connected to allow the water to flow directly into the round hole of the electrode before being discharged. In the above sense, artificial graphite can only be called a kind “Polycrystalline graphite”. However, this “polycrystalline graphite” has the basic characteristics of ideal graphite.

3. The Crystal Structure of Diamond

In the crystal structure of diamond, each carbon atom is covalently bonded with four adjacent carbon atoms, forming a regular tetrahedral coordination, which belongs to the equiaxed crystal system. Diamond is a typical atomic crystal. This structural feature of diamond, It is determined that the diamond is not conductive, and the thermal conductivity is also very poor. When heated to 1000°C in the absence of air, the diamond transforms into a graphite structure. When heated to about 780°C in the air, it will burn to produce carbon dioxide. The use of high-purity artificial graphite can obtain artificial diamond under high temperature and high pressure, but the particles of such artificial diamond are relatively small.

The advantage of this method is that it is easy to make the water system into a fully enclosed or semi-closed system without infiltration into the furnace. Because there is no need to drain the water tank, manufacturers using this method often make the water system a semi-closed system. The disadvantage is that the cooling effect is not as good as direct water spray cooling, and the water quality requirements are higher, and water shortage is strictly prohibited. Otherwise, the temperature of the furnace head rises and cold water is suddenly introduced, which may cause water explosion, which is very dangerous.