Cross-direction dryer for a machine producing sheet material moving in a machine direction having both gas powered and electric heating portions

摘要

A cross-direction dryer for typically drying a continuous web of paper or paper to which coating has just been applied provides both for baseline drying and a linear moisture profile by the use of respectively gas and electric heating portions of the heater units. Profile control is normally provided by control of the voltage to electric heating lamps. Such heating lamps are suspended over a large area gas burner to provide a combined increased infrared heat output. Encapsulation of the heating lamps with quartz provides for reradiation of the medium wavelength radiation produced by the gas burner. Thyristor switching for the quartz halogen heat lamps may be located adjacent to each heater unit and cooled by the combustion air for the gas burners.