This project encompassed the design, fabrication, installation and start-up of a new process line for a web coating and curing process line in a clean room environment. This turnkey installation included the web handling equipment, a 4-zone tower flotation oven and an interactive computer control system. The process required gentle handling of a light film product and the demanding service of oven operating temperatures up to 842°F (450°C).
The oven was designed with a hybrid heating system using indirect propane heated make-up air and electrical coil supplemental heat in the final three zones of the oven. The indirect heat is powered by a nozzle burner firing into a recirculating loop, through a plate type heat exchanger. The efficiency of the indirect system exceeds 95% . The make-up air is HEPA filtered and fed to the four oven zones. High temperature filters are provided in the recirculating loop of the first three zones. A cooling zone at the top of the tower cools the web with HEPA filtered outside air prior to it passing over the turn roll. A nozzle retraction system allows the nozzles to be set anywhere from 0.375" to 3.5" apart.
Careful design and consideration of the thermal expansion of the oven components was particularly important at these elevated temperatures to maintain the integrity of the floater system and its support of the web.
The computerized web handling equipment included an unwind, rod coater, web guides and web rewind. The computer interface control system allows for precise control of the entire line and recipe development.
The project was completed on time and on budget, while exceeding stringent performance specifications. Variable speed drives on all fan motors and precise control of each of the four zones result in a flexible process line, which will allow for process changes as well as accommodating new future products.