The weighing and dropping system realizes the process control of batching. According to the need of batching, various control function program modules and control subroutines are designed in the control software. It mainly includes "control system state initialization", "automatic work control", "manual work control", "automatic batching", "state test", "fault detection" and so on. The dosing control software follows the automatic control and manual control modes. In order to improve the performance of the batching control system, improve the accuracy and speed of the batching system, and ensure the reliable operation of the control system, effective measures are taken.

The automatic batching system is used as a central control area to complete the whole process of weighing and feeding. Before the equipment is equipped, the staff will open the switch, and the PLC central control area will send a signal to start the corresponding solenoid valve to inject the material into the reactor. At the same time, the weighing module will start to work. When the amount of the reaction tank is increased to the equivalent of the weight set by the quantitative setting reference, the central control area receives the action signal of the weighing module, and immediately closes the solenoid valve for adding materials and stops adding materials.

The batching weighing system is composed of a control computer, PLC, industrial weighing instrument, frequency converter, vibration motor, mixing machine, sensor, weighing screw conveyor, etc. Each hopper scale machine is equipped with a batching station. According to the number of daily storage bins, corresponding hopper scales are set up. Each hopper scale corresponds to a weighing instrument. Each daily storage bin is equipped with a hopper scale. One weighing screw conveyor feeds the materials in the daily storage bin into the hopper scale. When the weight set by the weighing instrument is reached, the feeding stops automatically and a discharge signal is sent. This signal enters the PLC system and is controlled by the PLC to discharge the weighing screw conveyor in the hopper scale. The feeding and weighing screw conveyor is controlled to start and stop by the weighing instrument and the PLC respectively.

Weighing and discharging system in is an organic whole, storage unit, dosing unit, control unit is the three inseparable basic units, is to ensure that the flow of material dosing of the necessary conditions. The basic unit of material and conveying link in the material changes will have an impact on the flow. Batching control not only rely on the improvement of the regulating device and the optimization of the control software to continuously improve the quality of the dosage regulation, but also with the dosage process is inextricably linked to the dosage process, only from the dosage engineering point of view, in order to grasp the direction of the development of the dosage control, to meet the modern industrial automation of the requirements of large-scale production.

The weighing screw system is composed of a driving part, a double-layer screw stirrer, a U-shaped barrel and a weighing module. The rotation direction pushes the material from both ends to the middle, and the inner screw pushes the material from the middle to both ends. The different angles and directions of the screw belt wind the material in different flow directions, and the material is rapidly mixed through continuous convection circulation and shear mixing. Pneumatic gate valve is set up in the center of the bottom of the horizontal cylinder, and the spiral structure of the outer spiral belt with the rotation direction of the main shaft drives the material inside the cylinder wall to the central outlet. The pneumatic gate valve is designed to control the lead amount of the end feed, so as to reduce the impact of the drop on the batching accuracy and keep the actual batching value within the error range.

The distillation tank weighing system adopts a computer with stable performance to complete the data acquisition and communication processing, which is convenient to provide processing accuracy and cost reduction, and the data output and management are carried out through the COM communication interface of the computer itself; Mitsubishi F900 touch screen is chosen to replace the conventional weight indicator to do the human-machine interface, which makes the programming of the interface between PLC and weight indicator become simpler, and enables the display function to be enhanced. The weighing system is to add two or more kinds of materials to the mixing tank automatically according to a certain weight ratio, and then automatically discharges the materials after mixing to meet the predetermined requirements.

The weighing system of the reaction tank is transmitted to the central control room for centralized monitoring and management through high-speed network, and the host computer of the central control room also transmits control commands to the PLC measurement and control terminal through high-speed network to implement decentralized management of each unit. Integrating computer technology, automatic control, communication technology, weighing technology as a whole, its control function is perfect, display, operation is centralized, data processing is convenient, installation, maintenance is simple, the system is easy to expand.

According to the predetermined formula, the measuring reaction tank will add a variety of materials into the weighing hopper according to the fixed proportion weight value. When the weighing is displayed to the amount, the materials will be discharged into the inlet of the mixing machine once or several times in steps according to the unloading procedure. It is also possible to control the weight and flow of the material loaded into the weighing hopper through the monitoring system and PLC program, so as to achieve accurate metering and batching. The system has strong stability and high cost performance, and can provide accurate measurement data and control means for production control and management of various industrial sites.

The intelligent batching system can adjust the size of the screw and the spatial distribution angle of the screw to achieve the adjustment of the flow rate. To achieve the purpose of precise quantitative conveying, the speed of the motor and the conveying time are changed through communication between PLC and frequency converter to realize precise quantitative conveying (quantitative range) or continuous conveying. The human-machine interface (HMI) adopts an industrial touch-type liquid crystal display. Through this control interface, the purpose of precise quantitative conveying and continuous conveying can be achieved, and at the same time, the current operating parameters of the frequency converter, such as conveying frequency, current, voltage, etc., and the rotation parameters of the motor can be obtained.