When the quantitative packaging scale enters automatic operation mode, the weighing control system opens the feed gate to begin material loading. This feeding device employs a two-stage feeding method: rapid and slow. When the material weight reaches the rapid feeding setpoint, rapid feeding stops while slow feeding continues. Upon reaching the final setpoint, the feed gate closes, completing the dynamic weighing process. The system then verifies whether the bag clamping device is in the predetermined state. Once the packaging bag is securely clamped, the system issues a control signal to open the discharge door of the weighing hopper, allowing material to enter the bag. After material discharge is complete, the discharge door automatically closes. Following material emptying, the bag clamping device releases, and the packaging bag automatically drops. After bag drop, the bag is sewn shut and conveyed to the next workstation. This cycle repeats continuously in automatic operation.

Classification and Characteristics of Hopperless and Hopper-Equipped Scales:

1. Hopperless Automatic Quantitative Packaging Scale

Also known as gross weight scales or auger scales, hopperless automatic quantitative packaging scales feature a relatively simple weighing and quantitative control process. The items to be packaged are directly loaded into a container or packaging bag for weighing. Quantitative control is achieved by regulating the opening size of the discharge gate.

These scales lack a dedicated "measuring hopper," with all weighing occurring inside the packaging bag. Essentially, the measuring hopper is omitted. The packaging bag is placed onto a bag-holding device, which is suspended and supported by load cells. The bag is then secured in place, creating a system that simultaneously fills the bag with material and performs weighing.

Features: Simple structure, high precision. Select weighing modules to form the weighing body with the weighing platform, or directly use a platform scale connected to a weighing indicator and simple control buttons to create a gross weight quantitative control device.

2. Hopper-Type Automatic Quantitative Packaging Scale

Also known as net weight scales, these systems control the quantitative discharge process through an intermediate measuring hopper. Initially, the discharge gate remains closed while the upper filling port opens for volumetric feeding. Upon reaching the target value, the filling port closes and the discharge gate opens to transfer material into containers or packaging, initiating the next control cycle. To enhance operational efficiency, multiple feeding speeds are available, typically dual-speed (fast and slow feeding). Alternatively, high-speed fixed-value control can be achieved using dual-scale rotation.

This hopper essentially functions as a scale, shaped like a material hopper. The entire hopper is suspended and supported by load cells, featuring a discharge gate at the bottom. Upon completion of measurement, the discharge gate opens, allowing material to flow into the bag, thus completing one weighing cycle.

Features: Integrated structure, high precision, fast speed. This configuration is commonly adopted for specialized weighing control equipment. By incorporating compatible load cells or load modules, weighing indicators, and control buttons, a net-weight quantitative control system can be established.