HIGH SPEED INFRARED/CONVECTION DRYER

摘要

A combination infrared/convection dryer or oven (10) for drying travelling webs (W). A shutter assembly (8) is provided between the infrared radiation source (16) and the moving web in order to selectively expose the web to infrared radiation. Drying efficiency is optimized by adding heated impinged air at high velocity on the machine direction ends and between the infrared elements. The air being discharged on the web is heated as it is pulled gross the elements to a centralized return air duct (42). The return air is pulled into the inlet of a close coupled supply fan (28) which then discharges the air to the nozzles. A portion of the air is also exhausted at atmosphere to maintain the oven enclosure in a negative pressure state, thus drawing fresh make-up air into the oven housing through the web inlet (12) and outlet (13) slots. Flotation nozzles (151, 152) can be used where contactless support of the running web is desired. Enhanced drying of the web and/or a coating on the web at high speed is achieved without a concomitant increase in dryer length.