2002 Annual Report
Research
Development of an Automatic Standard Milk Sample Packaging System
Roger Ruan, Professor
Paul Chen, Senior Research Associate
Ye-bo Li, Visiting Associate Professor
Shaobo Deng, Research Fellow
Funding Source
DQCI, Inc.; Minnesota Agricultural Experiment Station
Objective
To develop an automatic filling and sealing system for dairy calibration
standards.
Project Description
Commercial calibration standards for dairy product analyses are usually
produced weekly. These standards are normally contained in disposable
vials. Currently, many calibration standard producers employ primarily
manual operations in their production. These operations include filling,
capping, labeling, etc. Calibration standard producers are looking for
automatic packaging systems to improve production efficiency and filling
accuracy and reduce repetitive injury suffered by line workers.
Results
The plastic vial used for dairy calibration standard has a diameter of 1.25 inches and height of 3.25 inches. As this vial has a special cap, no conventional capping mechanism is available. In the current production practice, ten vials are placed in a plastic vial rack. Three different vial-capping mechanisms were designed and compared for performance. The final version of the vial-capping mechanism has a holding bar to tightly hold the vials during vial capping, an opening bar to gently and fully open the caps, and a closing bar to tightly close the caps without damaging the caps. These bars are operated with nine pneumatic cylinders through the capping mechanism. The liquid is pumped into a specially designed manifold and then dispensed to ten sets of liquid tubing. The tubing runs through a pinch area and then to the dispensing nozzles. The filling volume can be adjusted through controlling the amount of time that the pinch bar stays open. A Programmable Logic Controller (PLC) was set to automatically operate the vial capping, liquid filling, and label printing processes. The effects of nozzle dimensions, liquid flow rate, and milk fat levels on the liquid foaming and dripping were studied. The testing results show that this equipment can open and close vials gently and tightly. With the specially designed filling mechanism, no dripping was observed and the average filling volume of the ten vials is about 40.2 ml, with a the standard deviation of about 1%. This meets the filling volume design criteria of 40±1ml. The capacity of the developed system was 30-40 vials per minute.