Introduction to the Selection and Design Factors of Screw Conveyor

The selection and design of screw conveyors play a vital role in the filling coefficient, characteristic coefficient and comprehensive coefficient of conveying materials. The filling, characteristic and comprehensive coefficient of commonly used materials. What is the filling factor of a screw conveyor? The filling factor is the size of the cross-sectional area of the screw when the material is being transported, and the ratio of the cross-sectional area of the material to the cross-sectional area of the screw. That is filling factor.

The filling factor of the screw conveyor depends on the friction, viscosity, and pitch of the conveying material. Of course, if the screw conveyor has an inclination angle, the angle must be taken into consideration.

Let me introduce it in detail below.

1. For fluids (flour, rice) they hardly wear, the filling factor is 0.45.

2. For those with a small amount of abrasion and the material is granular or small (sand, coal), the filling factor is 0.33.

3. For materials with large density and loose materials with great abrasiveness and corrosively, the filling factor is 0.15.

In the following situations, we should reduce the filling factor of the material accordingly. 1. The filling factor of the screw conveyor axis inclined by 1 degree is reduced by about 2%. 2. When the screw pitch of the screw conveyor is large, reduce it by 10%. When the filling factor is smaller, the material accumulation height is lower, and most of the materials are closer to the outside of the spiral.

Therefore, it has a higher axial speed and a lower circumferential speed. The movement of the material in the conveying direction is much more pronounced than in the circumferential direction. The sliding surface of the movement is almost parallel to the conveying direction. At this time, the additional material is perpendicular to the conveying direction. The flow is weakened and energy consumption is reduced; on the contrary, when the filling coefficient is high, the sliding surface of the material movement is very steep, and its movement in the circumferential direction will be stronger than the movement in the conveying direction, which will lead to a reduction in conveying speed and additional energy consumption.

As a common conveying equipment for powdery materials, screw conveyors are often used in conjunction with bag filters. Customers are welcome to come to consult our bag filters and screw conveyors.