Infrared float bar
View Patent ↗Infrared air float bar for use in floating and drying a continuous planar web of a material in a dryer. Direct radiated or reflected infrared electromagnetic energy from an infrared light source in a removable channel assembly accelerates drying, or evaporation of solvents, or curing of web material passing in proximity to the bar, either by infrared electromagnetic energy, or in combination with convention airflow. The infrared source is cooled by pressurized air passing through an interior portion of the removable air bar channel assembly, and the air is further conducted into fluid contact with the web in an air gap between the emitter and web to promote convective heat transfer and to contribute to the air pressure field supporting web flotation. The removable channel assembly is configured for replacement of the infrared emitter and to allow the setting of the pressurized cooling air flow to the optimum level.
1. A method of drying a web of printed material having at least one region of wet ink coverage and at least one region without wet ink coverage, said method comprising impinging convection air on said web in combination with applying infrared heat flux simultaneously to said web in a pressure field created by said impinging air with a plurality of air jets, regulating a temperature of said impinging air such that said at least one region having wet ink coverage is heated by an infrared emitter source and by said convection air and said at least one region without wet ink coverage is heated by said infrared emitter source while simultaneously being cooled by said convection air; and
wherein said infrared flux is emitted from at least one infrared emitter source located between discharge slots creating said air jets and directing said air jets to impinge on said web creating said pressure field on the surface of said web, said infrared flux impinging simultaneously on said pressure field, and wherein drying air has wet bulb temperature of less than 180° F., and wherein said air jets are regulated to a temperature 30 to 100 Fahrenheit degrees above the wet bulb temperature of the drying air impinging on said web, and said convection air is heated to a temperature of 150 to 300° F.
2. The method of claim 1 , wherein said air jets discharge air at a velocity of from 5000 to 16000 feet per minute.
3. The method of claim 1 , wherein the web had a web direction, and wherein the heat flux from each infrared light source is 100 to 200 watts per inch across the web direction.