How to prevent rod reversal in the later stages of shutdown
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After several days of joint efforts and careful care, we saw that the rods in the furnaces were growing well. However, toward the end of the heating period, cracks caused by reduced current led to the rods collapsing, which was really disappointing! Please, the experts, offer some guidance! I am extremely grateful···
I wonder how long it will take to shut down the furnace at the OP’s place? What are the steps then? When we shut down the furnace here, there are few cases of the furnace being overturned, but cracks do definitely appear, and in some cases there is even some peeling. I believe the main influencing factors are that after the supply of materials is interrupted, hydrogen will continue to burn without a supply of material for some time; furthermore, when the furnace is shut down, the flow rate of gas should not be too high, otherwise excessive temperature differences between the surface and interior of the silicon rods can lead to an increase and spread of cracks.
What was said upstairs is correct, but I think it’s better to stop as soon as possible
It is also related to the magnetic field; if the distribution of this magnetic field is not proper, it can lead to uneven growth of the silicon rods, which in turn can cause the furnace to fail
Reply to 2# sc006: It takes about six to seven hours; gradually reduce TCS and H2 levels while maintaining the temperature, and lower the current appropriately. However, when the current reaches 70–80A, it can no longer be sustained, and things go haywire
It’s mainly a problem with the airflow; by properly controlling the flow rate of the air, the temperature can be reduced gradually.
Reply to 5# Qinghe Ying: The general steps are similar. If it’s in the later stages, I have two suggestions for you: control the airflow; you can reduce it a bit in those later stages, with hydrogen at 100 being sufficient； Another advantage is that the current can be reduced in steps, and the reduction magnitude can be decreased when the current drops to 200
Agree with the person above. Think about it: the rod does not fall over when burning without a load, which means that a significant reduction in the air-fuel mixture does not cause the rod to fall over. Therefore, the main factor is still current control – the temperature difference across the rod should not be too large.
What is the greatest impact of the inverted rod on the furnace?
Reply to 9# xpxue123: For the furnace, the main damages are to the furnace walls, as well as to the chassis and quartz rings; if the electrodes are damaged, it’s a serious issue. It also has a certain impact on electricity. Another point is that a furnace collapse can greatly damage the morale of the staff – after all, who doesn’t want to see the rods standing there in their complete form?
Reply to 7# sc006 3q, thank you so much, I’ve learned something.