The screw conveyor is a conveying machine without flexible traction components. It can transport materials horizontally, obliquely or vertically, and complete mixing and cooling operations while transporting materials. It has a simple and compact structure, reliable operation, easy maintenance, and low cost. In addition, because the trough is closed, it is convenient to transport materials that are easy to fly, hot and strong smell, which can reduce the pollution to the environment. Therefore, screw conveyors are widely used in the food industry, building material industry, chemical industry , machinery manufacturing, transportation and other industries.