Improving the performance of packaging scales is to ensure both weighing speed and high weighing accuracy. Compared to two speed feeding, a three speed feeding mechanism can effectively reduce the accuracy impact caused by material impact (drop) while ensuring feeding speed.

The three-speed feeding mechanism mainly designs three-level gates (large, medium, and small) on the feeding structure, and controls the opening and closing status of the gates based on time. The basic working process is as follows:

① Start and simultaneously activate large, medium, and small feeding for quick unloading;

② When the weighing value of the material is greater than the set value of the large feeding, close the large feeding, perform medium speed unloading, and wait for t1 time (to avoid overshoot);

③ Continue unloading. When the weighing value of the material is greater than the set value of the intermediate feeding, close the intermediate feeding, perform slow unloading, and wait for t1 time (to avoid overshoot);

④ When the weighing value of the material exceeds the target set value, close the small feeding, stop unloading, and wait for t2 time (to avoid vibration of the measuring hopper);

⑤ After the t2 time has passed, wait for the opening of the clamping signal. If the opening of the clamping signal arrives, unload the material into the packaging bag. If the opening of the clamping signal does not arrive, wait for the clamping signal;

⑥ When the weighing is less than or equal to the zero zone value during the unloading process, the unloading signal is turned off after a delay of t3 time, while the t4 and t5 timers are turned on. When the t5 time is up, the clamping signal is turned off and the packaging bag is loosened