Screw metering scales are divided into single-tube single-layer and double-layer types. The single-tube singlelayer type completes metering and conveying simultaneously, while the double-layer structure uses the upper layer for flow stabilization and conveying, and the lower layer for metering and conveying, offering better flow and saving space.

The length of the screw feeder can be determined according to actual conditions; according to the user, a double structure is generally used to complete material metering, which equipping a screw conveyor to be used in conjunction with the screw metering scale to complete material metering, mainly used for metering powder materials or small granular materials; it is widely used for the conveying and dynamic metering of powder and bulk materials in industries such as cement, chemical, metallurgy, ceramics, grain, and transportation. Commonly used materials include fly ash, slag powder raw material powder, and coal powder in the cement industry.

Working principle:

   The material is transported from the inlet through the screw conveyor to the metering screw connected below. The load installed on the metering screw detects the weight of the material and generates a voltage signal proportional to the weighing load, which is sent to the controller. Together with the preset screw speed dataduring metering, the metering screw runs at a constant speed, i.e., the speed signal is the design value of the metering screw), the instantaneous flow rate and cumulative weight value calculated. The control system compares the actual flow signal with the set flow signal, outputs a control signal to the frequency converter through PID regulation, and dynamically adjusts the speed of the feeding to achieve quantitative feeding.

Functional features:

 1. The feeding screw has a flow stabilization structure, ensuring the feeding powder sinks uniformly across the entire inlet cross-section, it difficult to bridge or surge.

 2. The flow-stabilizing feeding screw and the metering screw are synchronized in speed adjustment. The material filling coefficient of the flow-stabil feeding screw is 1.0, and that of the metering screw is 0.6. When the hourly output is adjusted over a wide range (1:10), the signal is accurate and the metering precision is high.

3. The screw blades are precision-made of manganese steel, which is highly wear-resistant and has a long service life.4. The screw clearance is small, overcoming the problem of backflow and surging, and avoiding material adhesion in the gap between the tube wall.

5. The sealed structure reduces dispersion.

6. There is a flexible connection between the flow-stabilizing feeding screw and the metering conveying screw, allowing the horizontal installation angle to be adjusted arbitrarily according to site.

Performance features: 

1. The controller uses an intelligent controller;

2. The combination of gravity weighing and screw conveying achieves dynamic continuous metering;

3. The structure is and the operation is smooth;

4. Automatic calibration and automatic zero-point measurement of the system;

5. Manual input of various parameters;

6. The instrument has a-diagnostic function and can be connected to a DCS system.