Classification of screw conveyors

Screw conveyors can be classified from different angles. According to the displacement direction of the conveyed material, it can be divided into two categories: horizontal and vertical. At the same time, according to the characteristics and structural differences of the conveyed materials, it can be divided into horizontal screw conveyors, vertical screw conveyors, flexible screw conveyors, and spiral tube (roller conveyor) conveyors. Among them, the spiral body of the vertical screw conveyor has a higher speed, and the friction of the material under the action of centrifugal force is used to achieve vertical transportation. It is suitable for powdery and granular materials with good fluidity, but the lifting height is usually not more than 8 meters. Horizontal screw conveyors are widely used in various scenarios.
When the material is added to the fixed machine trough, due to the gravity of the material and the friction between the machine trough, the material accumulated at the bottom of the machine trough does not rotate with the spiral body. Instead, it moves forward under the push of the rotating spiral blade, similar to a non-rotating nut moving in translation along the rotating screw, thereby realizing the conveying of materials. This screw conveyor is flexible in design, convenient for loading and unloading at multiple locations, and can also complete multiple functions such as mixing, stirring or cooling during the conveying process. However, it is sensitive to overload, prone to blockage, and has a certain amount of crushing loss to the material. Its structure is simple and easy to install, maintain and troubleshoot. It is suitable for continuous and uniform conveying of loose materials under horizontal or slightly inclined conditions (less than 20 degrees). Its operating environment temperature range is -20 to +40°C, while the temperature range of the conveyed material is -20 to +80°C. Compared with vertical conveyors, its speed is lower and it is mainly used for horizontal or small angle conveying of materials, and the conveying distance is usually not more than 70 meters.
In addition, there are spiral tube (roller conveyor) conveyors, whose casing is cylindrical and has continuous spiral blades welded inside. Under the action of centrifugal force and friction, the material will rotate with the casing and be lifted. Subsequently, under the action of gravity of the material, it slides down along the spiral surface, thereby realizing the forward movement of the material. This conveyor has low energy consumption, low maintenance cost, and can adapt to the requirements of uneven feeding. It can also complete multiple process requirements such as conveying, stirring and mixing at the same time, and will not cause jamming due to excessive material. However, it should be noted that the particle size of the added material cannot exceed a certain range, and the feeding temperature must be controlled below 300℃ to prevent the cylinder from deforming. In addition, this type of conveyor will cause serious wear on the blades and trough when conveying abrasive materials. Therefore, the characteristics of the material need to be considered when selecting. Since the screw conveyor designed this time is mainly used to convey silicon micropowder, which is very abrasive, it is not suitable to use a spiral tube conveyor.
In addition, there are also types of screw conveyors such as bendable screw conveyors, and their designs also have their own characteristics, which can be selected and applied according to specific needs.
The spiral mandrel of this machine is designed to be flexible, so that the conveying line can be flexibly arranged into a spatial curve according to actual needs. Its working principle can be designed according to the different ratios of horizontal and vertical sections, and can adopt the design of ordinary screw conveyors or vertical screw conveyors respectively. This conveyor is particularly suitable for occasions where material transfer needs to be avoided. Its spiral body has the characteristics of free floating. When there is too much material or hard lumps in the casing, there will be no jamming phenomenon, and the noise level is also low. It is mainly used to simultaneously complete horizontal and vertical transportation of materials, and the speed during vertical transportation is not less than 1000r/min.