Variable diameter flow guide cylinder for single crystal furnace

Abstract

The invention discloses a variable diameter flow guide cylinder for a single crystal furnace. The variable diameter flow guide cylinder comprises a heat shield outer liner, a heat shield inner liner and a thermal insulation material, wherein the heat shield outer liner comprises an upper heat shield and a lower heat shield, the upper heat shield and the lower heat shield are integrally arranged, the lower end of the lower heat shield is provided with an overlapping table, the minimum inner diameter of the overlapping table is larger than the maximum size of a to-be-drawn crystal, the heat shield inner liner comprises a carbon-carbon upper ring and a graphite ring, the carbon-carbon upper ring is an inverted tapered round table, the length of the carbon-carbon upper ring is not smaller thanthe vertical length of the upper heat shield, the graphite ring comprises a hollow inverted tapered round table 1 and a hollow inverted tapered round table 2, the hollow inverted tapered round table1 and the hollow inverted tapered round table 2 are sequentially arranged from top to bottom and are arranged integrally, the top end of the inverted tapered round table 1 contacts or forms snapped connection with the bottom end of the carbon-carbon upper ring, the bottom portion of the inverted tapered round table 2 is provided with an overlapping part, and the overlapping part is placed on the overlapping table of the lower heat shield. According to the present invention, the graphite ring with the corresponding specification is directly replaced according to the size of the to-be-drawn crystal, such that a set of the flow guide cylinder can be adapted to the size drawing of crystals with various specifications and models so as to save the cost, and the drawing process cannot be changedso as to achieve the good quality consistency of the drawn crystal.

Description

technical field [0001] The invention relates to the photovoltaic manufacturing industry, in particular to a variable-diameter draft tube for a single crystal furnace. Background technique [0002] The conventional size of the current single crystal furnace is about 8.5 inches for both the furnace type and the thermal field. However, with the start of grid parity in the photovoltaic industry and the accelerated iterative innovation of large-size monocrystalline products, the photovoltaic manufacturing industry as a whole has felt the new changes in the market. [0003] Under the new situation that the industry is moving towards bidding without subsidies, the value of large-size products has become increasingly prominent. [0004] "From the perspective of production line compatibility, market demand and product reliability, large silicon wafers will be one of the main development routes in 2019." The biggest advantage of large-sized silicon wafers is that they hardly increase...

AI Technical Summary

Problems solved by technology

When pulling large-sized crystals, such as 9-inch and 10-inch crystals, it is necessary to replace the guide tube with a relatively large inner diameter, which increases the cost. Due to the change in the size of the guide tube, the process changes greatly and affects the quality of crystal pulling.

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