The working principle of the screw conveyor in conveying materials is basically divided into three categories: a push method, centrifugal induction, and gravity sliding.
1. Push method: use spiral vanes for conveying materials commonly used in hopper bottom unloading and conveying. The materials are often filled with spirals, and the static pressure of granular materials is relatively large. The gravity of each material itself is much smaller than other forces (helical thrust, Friction, static pressure). This kind of spiral resistance is very big, it must overcome the friction force formed under the greater pressure. The work material is like a nut, spiral screw like effect, as long as the nut does not rotate (or slower rotation), the use of screw rotation, you can make the nut moves in the axial direction, the bottom of the discharge spiral often variable pitch spiral The pitch at the exit end is larger.
2.Centrifugal induction method:For screw conveyors with steeper vertical inclination, or any screw conveyor with higher rotation speed, the working characteristic is that the material filling amount is between two. Under the high rotation speed of the screw, the loose material is subjected to centrifugal force. The effect is far greater than other external forces such as gravity.
3.Gravity slide down method. The spiral speed is low, and the material on the spiral surface is affected by gravity far more than the centrifugal force. As the spiral rotating material continuously slides along the spiral surface, it generates axial displacement. The CX screw machine basically belongs to this principle. . The screw filling factor value of this principle is generally less than 0.5. Because of the overfilling, the material does not slide down the helicoidal surface, but rather it is agitated by the screw so that it flies over the screw shaft and does not get a large axial velocity. Since the material of the slow spiral is greatly affected by gravity, it is obvious that it cannot be used for the vertical spiral or the upward transport with a large tilt angle.
Slip-off principle, although the conveying capacity is low, but the material is in a state of free rolling and falling, and is less squeezed. It is suitable for materials that are easy to agglomerate and have great abrasive properties. When using a standard spiral, not only can it maintain a relatively fast down speed, but also have a certain adaptability to inclined transport (dip angle is generally within 20°).