1. Use graphite rods with good red heat uniformity in the heating section. Poor red heat uniformity of the rod will affect the uniformity of the furnace temperature and shorten the service life of the rod. In the process of use, the red heat uniformity of the rod will gradually become worse, and in serious cases, cause broken rods.
2. The higher the temperature of the graphite rod, the shorter the life of the rod, especially after the surface temperature of the rod exceeds 1500°C, the oxidation speed will be accelerated and the life will be shortened.
3. After the graphite rod is heated in the air, a dense silicon oxide film is formed on the surface, which becomes a protective film against oxidation and prolongs the life of the rod. Intermittent use, with the rise and fall of the furnace temperature changes, will lead to the rupture of the protective film on the surface of the rod, weakening the protective effect and accelerating the resistance value of the rod becomes larger.
In order to ensure the stability of the furnace temperature and meet the needs of rapid temperature rise, the supporting electrical control system should leave enough voltage adjustment margin - that is: when the new rod, at a lower voltage to meet the furnace design and use of power; with the use of time to continue, the rod resistance value becomes larger, it is necessary to correspondingly increase the use of voltage to meet The kiln design and the power users need to be increased accordingly. The graphite rod power adjustment method is recommended to adjust the power by adjusting the voltage. The recommended way to adjust the voltage of graphite rods is to choose SCR voltage or voltage regulator. Generally do not use the way to adjust the power by changing the circumference number of the power regulator.
4. Generally, the graphite rod surface load density is obtained from the relationship between the furnace temperature and the graphite rod surface temperature, and it is recommended to use the power with the maximum surface load density of graphite rod 1/2-1/3 value. The higher the power flow added to the graphite rod, the higher the surface temperature of the graphite rod. It is recommended to use the smallest possible surface load density (power).
Please note that the values recorded at the cold end of the graphite rod are the current and voltage measured in the range of 1050℃+-50℃ in air, which may not correspond to the actual use.
5. When using graphite rods continuously, please increase the voltage slowly to maintain a long life.
6. Connect graphite rods in parallel as much as possible. If the graphite rods have different resistance values, the graphite rods with high resistance will be connected in series and the load will be concentrated, which will lead to a rapid increase in the resistance of one graphite rod and shorten the life.
At the same time need to strengthen the resistance value of the group, that is, the same group of rods resistance value as close as possible. Generally, the deviation of the resistance value of the same group of rods in parallel is within 10%-15%, and the deviation of the resistance value of the same group of rods in series is within 5%-10%. The higher the furnace temperature, the smaller the required resistance value deviation should be.