Belt scale refers to an automatic weighing device that continuously weighs bulk materials on a conveyor belt without the need for mass subdivision or interruption of the conveyor belt's movement. The electronic belt scale weighing bridge is installed on the conveyor frame. When the material passes by, the measuring roller detects the weight of the material on the belt conveyor and acts on the weighing sensor through a lever, generating a voltage signal proportional to the belt load. There is a weighing sensor installed on the weighing bridge on the belt scale. During operation, the weight of the material detected on the belt is sent to the weighing instrument. At the same time, the speed signal of the belt conveyor is also sent to the weighing instrument by the speed sensor. The instrument integrates and processes the speed signal with the weighing signal to obtain instantaneous flow rate and cumulative measurement. The speed sensor is directly connected to the large-diameter speed measuring roller, providing a series of pulses, each pulse representing a belt movement unit, and the frequency of the pulses is proportional to the belt speed. The weighing instrument receives signals from the weighing sensor and speed sensor, integrates them to obtain an instantaneous flow rate value and an accumulated weight value, and displays them separately.

The belt scale adopts a base, a pillar, an active shaft, a driven shaft, a fixed shaft, a conveyor belt, a weighing roller, and a support frame. The two side walls of the base are fixedly connected to the pillar, and the top of the pillar is fixedly connected to the center of the fixed shaft. The outer wall of the fixed shaft on the left is hinged with the active shaft, and the active shaft is electrically connected to the motor. The outer wall of the fixed shaft on the right is hinged with the driven shaft. The outer walls of the active shaft and the driven shaft are equipped with a conveyor belt. The motor drives the active shaft to rotate, and the driven wheel rotates under the drive of the conveyor belt. A support frame is fixed between the pillars, and the support frame adopts an upper pressure plate, a lower pressure plate, and a connecting piece. One side wall of the connecting piece is fixedly connected to the side wall of the pillar, and the The upper pressure plate is placed above the lower pressure plate, A weighing module is fixed between the upper and lower pressure plates near the driving shaft, and a weighing module is fixed between the upper and lower pressure plates near the driven shaft. At least two weighing roller bases are fixed at the top of the upper pressure plate, and an alarm and control box are fixed at the top. The control box is placed on the right side of the alarm, and a PLC controller is installed inside the control box. The outer wall of the left pillar is fixed with a support plate, and the top of the support plate is fixed with a speed sensor. A weighing instrument is fixed on the outer wall of the right pillar. The weighing module and sensor respectively test the weight at different positions. The weight obtained from the test is compared by the PLC controller. If the error value is exceeded, the PLC controller will activate the alarm.

The speed regulating belt scale adopts a system structure with weighing instruments as the control core, forming the belt scale controller BWF. The hardware part mainly consists of weighing instruments, Weighing modules, amplification circuits, latches, etc. Batching relies on adjusting the speed of the belt conveyor to control the feeding amount of raw materials and complete the proportioning of various raw materials. The belt scale is a real-time controller used to measure and control the speed and material flow of the belt conveyor. There is a hopper above the belt structure, and the material is conveyed out with the belt during its movement. The conveyor belt is driven by a slip motor (electromagnetic speed regulating asynchronous motor), and the frequency of the speed sensor output signal is proportional to the belt speed. A weighing module is installed below the conveyor belt, which outputs a voltage signal proportional to the material on the belt. The speed signal and weight signal received by the belt batching scale controller calculate the instantaneous flow rate of the material on the belt and display it. The actual flow rate value is compared with the set flow rate value through PID Adjust the output current control signal and amplify it through a preamplifier and power amplifier to control the conduction angle of the thyristor, thereby adjusting the speed of the slip motor and stabilizing the material flow rate at the expected set value.

Before the belt conveyor is put into operation, the set value of material flow on the conveyor belt is set by the operator on the keyboard. After the system is put into normal operation, the weighing instrument samples the belt load signal and speed signal, and multiplies the belt speed signal with the instantaneous weight per unit length of the belt to calculate the instantaneous flow rate of the material on the belt. Instantaneous flow can be displayed through six seven segment digital tubes, providing process data reference for operators. The weighing instrument system then compares the actual flow value with its set value, calculates the control quantity through incremental PID adjustment calculation, and outputs the current signal (4-20mA) through the weighing instrument. Then, it amplifies it to control the conduction angle of the thyristor, achieving the function of adjusting the excitation current of the electromagnetic clutch of the slip motor, thereby adjusting the speed of the actuator slip motor, making the material flow on the conveyor belt as stable as possible near the set value, and having good static indicators and dynamic performance.