Working Principle of Screw Metering Scale 

The core of a screw metering scale (also known as a screw volumetric feeder or screw feeder) is divided into three main parts: the screw conveying mechanism the weighing detection unit the variable frequency speed control system. It achieves continuous and precise batching and metering by volumetric conveying real-time weighing closed-loop regulation. 

 I. Principle of the Mechanical Conveying Part The motor drives the reduction mechanism to rotate the screw blades, pushing powder or granular materials in the hopper forward, uniformly filling the internal cavity of the screw casing. The screw cavity is a sealed structure, preventing dust, material bridging, and leakage, it suitable for materials with average flowability such as fly ash, mineral powder, grain, and chemical powders. The theoretical volume of material pushed by the screw per unit of time is by the pitch, the outer diameter of the screw, and the rotation speed, which is the basis of volumetric conveying. 

 II. Core Principle of Weighing and Force Measurement ( Mainstream Structures)

 1. Integral Weighing Type (Whole-machine suspended weighing, commonly used for high precision) The entire screw cylinder, screw shaft, and drive motor are suspended and supported by weighing sensors, with no rigid hard connections: The total weight of the material inside the screw acts entirely on the weighing sensors, and the sensors output the weight signal real-time; The control system collects the instantaneous weight and the screw operating speed, calculating the instantaneous flow rate according to the formula: Q = m × v Q Instantaneous flow rate (t/h); m: Weight of material per unit length (kg/m); v: Linear speed of the screw (m/h)Continuous integration and accumulation are performed to obtain the total cumulative discharge weight.

 2. Bridge Section Weighing Type (Short-section weighing, economical type) A weighing bridge section intercepted in the middle of the screw, weighing only the weight of the material in that section, while the rest of the cylinder is fixed. The instantaneous material weight of the entire screw converted through the material load of this section, which has a lower cost and slightly lower accuracy than the whole-machine suspended type.http://www.zhitianmeteringequipment.com/product/tubular-screw-conveyor