Will make large graphite blocks difficult to obtain or cost too much
The use of an induction heating furnace for polycrystalline silicon ingots and purification is one of the means for crystal growth and purification in the field of solar cell silicon materials. The characteristic of the induction heating furnace is that the graphite heater used is integral graphite, and it does not need to be slit into strips to improve
And adjust its resistivity, so it has a longer service life and is easier to process than graphite heaters using resistance methods. Generally used in
The frequency-heating polysilicon ingot furnace uses a circular heating coil and a circular heater, and a square crucible for polysilicon ingots.
The pot cannot form a tight heat transfer space, and the graphite heater is processed by a single piece of graphite.
The car goes to the center of the heating body, causing a lot of waste due to the high cost of the heater, especially when the ingot is several hundred KG in weight
As a result, large graphite blocks are difficult to obtain or the cost is too high. Purification furnace is usually carried out by intermediate frequency ingot furnace.
When pure, the phenomenon of skipping and so on often occurs, which makes the heater easy to break, which further increases the cost of the heater. Cast in polysilicon
In the smelting process of ingots and their materials, it is often necessary to develop square ingots to obtain the best material utilization. The crucible used at this time is
Square, when considering the energy saving of the overall heating system, such as the intermediate frequency heating coil (usually copper coil) from the conventional garden shape
Change to square. Since the silicon material is a semiconductor, intermediate frequency heating is not directly induced on the silicon material, but on the outside of its crucible.
The thermal energy generated by the graphite body is transmitted to the crucible on the graphite body at the center, so this graphite body is often called a graphite heater. At this time
The induction heater in the coil is also made into a square shape, so the coupling with the square crucible is better, and energy can be saved. This square
Heater, ideal state is to use a large block of graphite processed into a square tube heater to ensure ring-shaped induction current
Produced to achieve the purpose of heating. Especially in the purification of silicon materials, due to the impure material and the use of high-quality
Air and high temperature for purification, the loss of the heater is large, the combined heater can greatly reduce the heating
Cost of the device. Conventional heaters are processed by using a single block of graphite cart to the inside, and the cost of materials is very high.