Working Principle, Structure, and Applications of Screw Conveyors

Release time:

2021-07-19

Working Principle, Structure, and Applications of Screw Conveyors

　　A screw conveyor consists of a load-bearing component supported by upper and lower support rollers, as well as a conveyor belt that serves as the traction element. It is a continuous-loop conveying machine with an over-wound configuration and a tail roller that forms a closed loop. Power is transmitted through the friction between the drive roller and the conveyor belt, enabling the transport of materials. Next, let’s take a closer look at the working principle, structure, and applications of the screw conveyor!

　　A screw conveyor is a continuous conveying machine that does not use flexible traction elements.

　　1. The main components of a screw conveyor used for conveying granular materials dispersed in horizontal and slightly inclined directions include a semi-circular material trough and a helical screw mounted on suspended bearings inside the trough. The screw rotates driven by a drive unit. Materials enter the trough through a hopper and are discharged from a central outlet. For vertical screw conveyors that transport scattered materials in the vertical direction, the helical screw is suspended from upper bearings, while the lower end is centered by a thrust ball bearing. The feeding section of the trough consists of a conical pipe, with the remaining portion being cylindrical. The drive unit at the top rotates the screw, allowing materials to be fed from the bottom and discharged from the top.

　　2. Working Principle, Features, and Applications. The working principle of a screw conveyor is as follows: The screw rotates inside a closed casing. The material fed into the casing, due to its own gravity and friction against the casing walls, does not rotate along with the screw but instead moves forward along the length of the casing. In a vertical screw conveyor, the material moves upward under the influence of centrifugal force and friction generated by the side walls of the trough.

　　Main advantages of screw conveyors:

　　1) The structure is relatively simple, compact, and easy to manage and operate.

　　2) Reliable performance, relatively simple maintenance, and low cost.

　　3) Due to the enclosed nature of the storage tank, dust is less likely to fly around, making it convenient to transport high-temperature (200°C) and strongly odorous materials, thereby reducing environmental pollution and improving working conditions.

　　4) It can easily achieve multi-point supply and multi-point discharge;

　　5) A conveyor belt can transport materials in two directions simultaneously—either concentrating them toward the center or moving them away from the center.

　　6) Can be used in conjunction with processes such as transportation, mixing, stirring, or cooling;

　　7) Due to the high rigidity of the tank, it can effectively withstand certain bending moments. The main drawbacks of screw conveyors are that, because of the mixing action of the screw on the material and the friction between the screw and the material, they exhibit high running resistance and power consumption, leading to rapid wear of components and heavy maintenance requirements. Additionally, they are sensitive to overloads and prone to blockages.

　　3. Due to the reasons mentioned above, screw conveyors are widely used in various industrial sectors—including construction materials, grain processing, chemicals, mechanical manufacturing, and transportation—for conveying materials such as cement, coal powder, ore, and wheat flour. For screw conveyors used to transport materials horizontally or at slight inclinations, the inclination angle should be less than 20 degrees. When configuring a conveyor belt, if possible, place the drive unit at the discharge end to keep the screw in a favorable tensioned state. Additionally, take care not to position the support platform or discharge outlet on the flange of the housing joint, nor to place the feed inlet directly above the cover joint or lifting bearing.

　　The above is an introduction to the working principle, structure, and applications of screw conveyors. If you’d like to learn more, feel free to contact us anytime!

Jiangsu Yaxing

Address: Qingdun Industrial Park, Hai'an City, Jiangsu Province

Phone: 86-513-88483622 ，86-513-88480666,

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