The introduction of molybdenum draft tube into single crystal furnace is an important improvement. After using the molybdenum draft tube, the argon in the upper part of the single crystal furnace becomes smooth, the argon flow accelerates, and the deposition of silicon oxide on the single crystal furnace is greatly reduced. Because of the temperature protection of molybdenum draft tube, the heating time is reduced, the crystallization time is shortened by nearly 35%, and the occurrence rate of crystal dislocation is also reduced. Therefore, the application of molybdenum draft tube reduces energy consumption and improves production efficiency.

The shape of molybdenum draft tube is a large upper opening and a small trumpet-shaped lower opening. The upper opening has a variety of styles due to different single crystal furnace manufacturers, and its specifications include 16 inch, 18 inch, 22 inch, etc. Generally, 0.8-2.0mm high-temperature molybdenum plate is used to produce and process molybdenum draft tube, and the plate is cut into sectors according to the size of the drawing, heated and rolled into a horn shape, riveted or welded, and finally corrected. In order to save costs, molybdenum sheet splicing processing is also used to produce molybdenum draft tube. There are many rivets, which will affect the service life.

The finished molybdenum draft tube has a smooth surface, the upper and lower diameters are concentric, and the size is accurate. It can closely fit with the graphite guide cylinder. The unit weight of the finished product is 3-10 kg.