Development Of Automatic Weighing Machine For Orange

Fruit weighing and packing, as the tail end of the fruit grading flowline, are playing important role in fruit post-harvest commercial processing. For the vast majority of Chinese fruit grading flowlines, weighing and packing are completed still by hands, costing much time and labors and greatly reducing the overall efficiency of the flowlines. Therefore, inefficient weighing and packing have become the bottleneck for the improvement of fruit commercial processing efficiency in China.Based on the classification according to fruit weight, fruit automatic packing in abroad is able to weigh and pack fruit online, however, it requires huge facility input and use-cost. Therefore, the foreign automatic packing machines are not acceptable for medium-or-small-size producing enterprises of fruit in China. However, no information is currently available regarding on development of fruit weighing and packing machine, which is able to automatically weigh and pack fruits on flowline in China. The objective of this paper is to design a GFB-1 type of orange automatic weighing and packing machine to weigh and pack fruit according to the purposed weight capacity.Starting with studying the single technology and key component, and basing on the completion of key component designing, parameters testing and trial-producing of prototype, the author succeeded in developing a set of reliable, affordable fruit automatic measuring and packing equipment by further optimizing the design of whole machine structure and process.GFB-1 type of orange automatic weighing and packing machine including design scheme, working principles, structural composition, working features and main parameters et al. Rapid and precise feeding of the machine was ensured by employing wide and narrow feeding channels which were matched with wide and narrow roll troughs, respectively. The machine was able to alternately weigh left and right boxes side by side. Gravity signals derived from sensors were fed back to Programmable Logic Controller (PLC),the control system, and control the electric motors of the wide and narrow roll troughs to turn left and right automatically and to ensure continual working of the machine. The experimental results showed that the productivity was about 4-6 box/min, mean error of each box was less than 160g, weight capacity per box varied from 2.5 kg to 10 kg(set manually), and percent of damaged fruits was less than 1.7 percent.Fruit weighting and packing of the machine was completed in dynamic status, during which the weighing sensors were greatly influenced by the impact caused by falling fruit. It is necessary to alleviate the influence on weighing sensors. Therfore, different shock absorbing methods were used to investigate their effects on the qualified rate of the machine's packing, then coming up with suitable shock absorbing measures. By contrast testing, buffering spring combined with foam plastics was taken as the shock absorbing means, and the qualified rate of the machine's packing was maintained at more than 95 percent. Reading error of the sensors can be reduced by improving PLC program, setting the time delay in the range of 0.5～ls. The PLC control system has the function of error alerting, which reminds of the operator to amend the unacceptable error manually, to ensure 100 percent of the qualified rate.The manufacturing process of the prototype machine as well as the composition and method of the automatic control system were also presented in the paper.