Multiple Silos Single Weigh Type

The multi-silo single-weighing static automatic batching system is an automated batching device based on the collaborative work of sensors, PLC controllers, and actuators. The system typically consists of a control unit, software unit, weighing unit, feeding unit, and conveying unit, achieving automated control of the process from raw material input to output.

The core technology of the multi-silo single-weighing static automatic batching system lies in the integrated design of "multiple silos, one weigher" and the high-precision metering method of "static weighing." In static batching mode, various materials are stored in different silos, and silo feeding generally uses methods such as vibratory feeding, screw feeding, or star feeding. Unlike dynamic batching, static batching is suitable for scenarios with strict requirements on the composition ratio of single batches, batching is performed, and each batch consists of multiple materials. The "multiple silos, one weigher" design of this equipment—multiple raw material silos sharing the same weighing unit, each silo sequentially feeding material into the same weighing hopper, completing weighing one by one—effectively avoids the problems of weighing deviation and data asynchrony in multi-weighing equipment.

The equipment adopts a distributed system structure, with a "host computer + PLC system + solid batching control instrument" model ensuring the system's openness and reliability. The system can weigh various materials in different forms, including powder, granules, and lumps. It is equipped with comprehensive safety protection designs, including overload protection, emergency shutdown, and material detection devices. The enclosed silo and conveyor structure effectively reduce dust spillage, meeting environmental protection production standards.

Equipment Structure

The technical architecture of a silo-based static automatic batching system mainly consists of the following layers:

(I) Execution Layer (Feeding Section): The feeding section is the actuator that adds material from the silo to the weighing equipment. Different feeding devices can be selected based on the characteristics of the material, such as electromagnetic vibratory feeders, screw feeders, rotary valves, and pneumatic batching valves (pneumatic butterfly valves, slide gate valves), etc. Each silo is equipped with an independent feeding device, effectively preventing cross-contamination during the batching process. The feeding device receives instructions from the control system to complete the quantitative conveying of materials.

(II) Sensing Layer (Weighing Section): The weighing section consists of a single high-precision load cell (or sensor group), standard connectors, a junction box, and a weighing hopper. Each silo shares the same weighing unit—materials enter the weighing hopper sequentially, and the sensor monitors weight changes in real time. The load cell adopts a cantilever beam or S-shaped structure, offering high accuracy and good sealing performance. Soft connections are provided at both the top and bottom of the weighing hopper to reduce frictional interference during the weighing process. (III) Control Layer (Material Batching Control System): The material batching control system consists of a programmable logic controller (PLC), weighing instruments, a host computer, and other control devices. The PLC, as the core of the system, is responsible for executing control programs, processing sensor signals, and outputting control commands. The host computer is responsible for the dynamic monitoring and data acquisition of the entire production line, managing various curves, parameters, production reports, etc. The human-machine interface provides an interactive platform for operators. Connections between devices are made via RS485 fieldbus.

(IV) Conveying Layer (Discharging Equipment): This includes pneumatic flap valves (or electric valves), belt conveyors, etc. After all materials are batched, the pneumatic flap valve at the bottom of the weighing hopper opens, discharging the materials onto the conveyor and sending them to the mixer or the next process.

Control system working principle

The working principle of the control system of the multi-silo single-weighing static automatic batching system is as follows:

(I) Recipe Input: Operators input the target recipe via a host computer or human-machine interface. The system can store hundreds of recipes.

(II) Sequential Control: The PLC control system starts the feeding devices of each silo sequentially according to the recipe requirements. The feeding devices adopt variable frequency speed regulation technology, which can realize step-by-step feeding with "fast feeding" and "slow feeding".

(III) Real-time Feedback: The weighing sensor converts the weight signal of the material into an electrical signal and transmits it to the weighing instrument. The weighing instrument converts the analog signal into a digital signal and transmits it to the PLC. The PLC judges in real time whether the current weight has reached the set value.

(IV) Automatic Correction: The system has an automatic drop correction function, which can automatically adjust the feeding parameters according to the material characteristics to adapt to different materials.

(V) Data Management: The host computer automatically stores the recipe information, batching data, production time and other key parameters of each batch of production, forming a traceable production ledger.

Equipment operation procedures

(I) Formula Setting: The required formula can be retrieved or input via the human-machine interface or host computer. The target weight and allowable error range for each raw material are set.

(II) Automatic Batching: After system startup, the PLC controller sequentially controls the feeding of materials from each hopper. Sensors monitor the weight in real time, and the system automatically stops when the set value is reached.

(III) Unified Discharge: After all materials are batched, the system automatically opens the discharge valve.

(IV) Cyclic Operation: After discharge is completed, the system automatically enters the next batching cycle.

Equipment maintenance methods

(I) Control System Maintenance: Regularly check the PLC controller's operating status. Regularly check the host computer software's operation. Regularly back up recipe parameters and production data. Check if the RS485 communication line is functioning properly.

(II) Weighing System Maintenance: Regularly calibrate the weighing sensors. Check if the junction box is wet or damp. Check if the wiring cables are intact.

(III) Actuator Maintenance: Regularly check the pneumatic valve's operating status. Regularly check the wear condition of the feeding device. Clean the accumulated material from the vibrator.

Equipment troubleshooting

(I) Control System Communication Failure: Communication between the host computer and the PLC is interrupted. Causes include RS485 line failure, loose interface, interference, etc.

(II) Weighing Sensor Failure: Inaccurate weighing data or abnormal display. Causes include sensor damage, moisture, uneven force, etc.

(III) Feeding System Failure: Poor or impossible feeding. Causes include feed motor damage, frequency converter failure, material blockage, etc.

(IV) Pneumatic System Failure: Pneumatic valves are not responsive. Causes include insufficient air pressure, damaged solenoid valves, etc.

Application of equipment in production line

The multi-silo single-weighing static automatic batching system is located between raw material storage and mixing in the fertilizer production line, undertaking the core task of precise batching. This equipment adopts a "multi-silo, single-weigher" design, typically supporting flexible configurations of 3-8 silos. The entire production line requires only 1-2 people to operate.