What are the sensors in a belt weigher? What are their functions and characteristics?

A belt weigher is installed on a belt conveyor to dynamically and continuously weigh the material passing over the belt without interrupting the conveyor's motion. To accomplish material weighing, sensors are used to obtain raw data, primarily consisting of two types: the material's weight signal and the belt's speed signal. The product of these two gives the instantaneous material flow rate, and their accumulation gives the total material weight.

As indicated by the above simple calculation of the belt weigher, its sensors mainly include two types: weight sensors and speed sensors.

(1) Weight Sensors

Weight sensors are installed on the frame of the belt weigher, between the load-bearing device and the base installation surface. When material passes through, its weight is applied to the weight sensor, which then captures the material weight signal and outputs a load signal proportional to the weight. Therefore, weight sensors are a crucial and primary data source for obtaining material weight in a belt weigher and can be considered as its core component.

Weight sensors have various classifications, mainly including resistive strain sensors, piezomagnetic sensors, and differential sensors. Resistive strain sensors are primarily used in belt weigher weight sensors. A resistive strain sensor installs a resistance strain gauge on an elastic body. When the elastic body deforms under external force, the strain gauge converts this deformation into an electrical output. Corresponding measurement instruments detect this electrical output, which has a proportional relationship with the external weight, to calculate the mass.

Guonuo Technology's belt weigher weight sensors are structurally divided into S-type shear structures and cantilever structures. S-type sensors are small in size and have strong resistance to pressure. Cantilever structures have good automatic centering and interchangeability under load. Regardless of the structural type, weight sensors exhibit excellent precision and sensitivity, feature automatic calibration to reduce measurement errors, and have a sealed design for dust and waterproofing, maintaining their operational stability.

Belt weigher weight sensors are divided into analog sensors and digital weight sensors based on their signal modes. The latter has stronger anti-interference capabilities, more accurate load signal release and transmission, and higher measurement accuracy than the former.

Additionally, it's worth mentioning that for belt weighers used in explosive environments like coal mines, their weight sensors are explosion-proof, featuring intrinsically safe designs and stainless steel explosion-proof casings.

(2) Speed Sensors

Another important data source component in the operation of a belt weigher is the speed sensor, which is directly connected to the speed roller and provides a series of DC pulses. Each pulse represents a unit of belt movement, with the pulse frequency proportional to the belt speed. The instrument receives the speed signal and processes it simultaneously with the load signal from the weight sensor to determine the instantaneous and cumulative flow rates of the material.

Belt weigher speed sensors are mainly classified into single-wheel and double-wheel structures based on their structural types. Guonuo Technology's belt weigher speed sensors adopt a double-wheel structure with a rubber-coated design to prevent skipping, ensuring high stability and accurate reflection of the belt speed.

Belt weigher sensors are primarily divided into weight sensors and speed sensors, which are the direct sources of operational data for the belt weigher.