Post-mix Beverage Machines Fuzzy PID Temperature Control System

With the required higher quality of consumers for beverage production and moredemand on energy saving for beverage production equipment in the world, theenhanced performance of post-mix carbonated beverage dispenser becomes thecritical technology in the industry.The CCDX dispenser replaces the water tank in traditional machines with a thinmetal water loops and an aluminum evaporator as heat exchanger in its original design.Compared with traditional dispensers it improves the cooling efficiency of drinkingwater and shortens the interval time between two cups. But the original design hassome problems such as the water frozen in the pipe for the unreasonable temperaturesetting and the Initial Pull Down cannot meet the standard time. It also cannot solvethe confliction between the required narrow temperature range that ensure productquality and the wide temperature range that save energy.In this thesis, it is analyzed and carried out on both of the inherent defects inCCDX dispenser of the temperature parameter setting control system and theinfluencing factor of drink temperature. By changing the cooling path of syrup, theInitial Pull Down issue is solved. By applying Fuzzy-PID control which based on theheating load change, the frozen issue is solved and the energy saving requirement inthe industry standard can be met. The temperature control system should switch toPID control to get quicker response when there is over-modulation in the system, itshould switch to fuzzy control to get better performance when temperature deviationachieves range of2℃e2℃. In the process of compressor control, the systemmeasures temperature with thermo-sensor, the rate between the temperature and timeof the aluminium block can be obtained. The rate indicates the change of the heat-loadof the machine. Working area can be judged by this rate. The different temperaturesetting of compressor On/Off at next cycle can be assured and the influence of theheat-load is effectively decreased.The test result shows that improved dispenser by applying Fuzzy-PID controlbased on the heating load change can solve the technical problem met in production.The quality of the beverage and the production efficiency can be improved.