Temperature Control of a Shrink Tunnel with Multiple Heating Zones

Shrink tunnels are widely used in manufacturing applications for polymeric packaging. In this chapter, we propose a lumped-parameter model for a shrink tunnel composed of an industrial oven and a conveyor belt that feeds bottled beverages to it. The oven is used as a final step in bottle packs manufacturing processes. In particular, sets of bottles are mechanically grouped together and covered by a thin plastic film before being inserted into the oven. The heat shrinks the plastic and tightly envelopes the bottles, creating the pack. The quality of the wrapping is related to the temperature distribution within the oven. Thus, a proper closed-loop control scheme is necessary. The control objectives are: (i) setpoint tracking, (ii) disturbance rejection, and (iii) energy saving. Designing a control strategy for the system under study can be challenging due to underactuation, nonlinearities, and the presence of time delays.