Directional solidification technology is the most important production method of polycrystalline silicon ingot. It is very necessary to optimize the heat field of directional solidification furnace, because the thermal field determines the quality of polycrystalline silicon ingots to a great extent. The Weld preheater provides heat source for the whole directional solidification furnace heat field system, and is the most important factor to control the Heat field. With the increasing of the size of the silicon ingot, in order to control the Heat field better, the solidification furnace with multiple Weld preheaters is widely used.
In the ingot furnace with multiple Weld preheaters, the position and power distribution of the Weld preheater will affect the Heat field, flow field and solid-liquid interface form in the furnace. Therefore, it is necessary to study the influence of Weld preheater position on the heat field of the furnace in order to obtain a larger size and better quality silicon ingot.
Some researches have been done on polysilicon ingot furnace Weld preheaters. The effect of different power distribution on the melting, crystallization process and annealing of silicon material was analyzed by numerical simulation.
The results show that the different power distribution has a significant effect on the whole directional solidification process. The effects of the shape of the heat insulating layer and the position of the Weld preheater on the directional solidification of polycrystalline silicon were maxu and simulated.
The results show that the position of the Weld preheater can affect the morphology of the solid-liquid interface. The Heat field of the top Weld preheater, the side Weld preheater and the top-side Weld preheater were simulated by Dai Xin. The results show that the crystal growth process can obtain better efficiency and solid-liquid interface when using the top-side Weld preheater.
First, the silicon is added to the crucible and the temperature is completely melted, the process first power control and then into the temperature control; Secondly, the process is temperature control by raising the heat insulating layer of the side and adjusting the Weld preheater power to reduce the temperature properly. Finally, the crystallization is finished after annealing and cooling. In order to simplify the model and calculation, the assumption is as follows: The whole system is two-dimensional axisymmetric and the heat transfer process is quasi steady during crystallization.
Now this period is the peak of the installation of fuel Weld preheaters, in order to better facilitate the user and distributor the correct installation of Weld preheaters to share the attention of the installation and use.
1 fuel is used to meet the seasonal temperature of diesel.
2 fuel pipes do not have a large angle of bending, the tubing connection to ensure that the seal does not leak.
3 the air duct and exhaust pipe must be installed, and the external joint of the two pipes shall not be less than 50CM
4 power cord is taken directly from the battery.
5 Host level installation, the floor sealed securely ensure that the exhaust does not return.
6 fuel pump outlet angle to ensure that the level of 15-30 degrees in the best state.
7 vehicles in the gas station and flammable powder space please turn off the Weld preheater.
8 each boot in high-end operation 10 minutes after the transfer of small stalls.
9 Night long use of Weld preheaters must ensure that indoor air circulation.