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 channel assembly adapted to be inserted into an air bar, said channel assembly having a compartment defined by a bottom having a pair of opposing sides and at least one aperture having an adjustable open area, said compartment comprising an infrared light source for emitting electromagnetic energy, a reflector for reflecting electromagnetic energy emitted by said infrared light source, a lens transmissive to infrared light emitted from said infrared light source, said lens having opposite terminal ends and first and second spaced elongate longitudinal lens edges extending between said opposite terminal ends, and having a surface defined between said first and second spaced elongate longitudinal lens edges, and at least one elongate longitudinal slot extending between said first elongate longitudinal lens edge and one of said opposing sides of said compartment, wherein a boundary of said at least one slot is defined by said surface of said lens, wherein when said channel assembly is in said air bar in operation in a dryer for floating a web, cooling air flow from said at least one slot is discharged from said compartment parallel to said lens, sweeps said surface of said lens, and provides at least a portion of flotation air for floating the web.
2. The channel assembly as claimed in claim 1 , wherein said channel assembly further comprises an adjustment member positioned in said channel assembly and having at least one adjustment member aperture alignable with said at least one aperture of said bottom so as to reduce said open area.
3. The channel assembly of claim 2 , wherein said at least one aperture in said bottom and said at least one adjustment member aperture are diamond shape.
4. The channel assembly of claim 2 , wherein the open area of said at least one adjustment member is smaller than said open area of said at least one aperture of said bottom.
5. The channel assembly of claim 2 , further comprising a source of supply air for delivering air to said channel assembly, and wherein said adjustment member restricts said open area of said at least one aperture in said bottom to from 5 to 40% of said supply air delivered to said air bar.
6. The channel assembly of claim 5 , wherein said adjustment member restricts said open area of said at least one aperture in said bottom to from 7 to 15% of said supply air delivered to said air bar.
7. The channel assembly of claim 1 , wherein said reflector has at least one reflector aperture that is alignable with said at least one aperture having an adjustable open area.
8. A method of setting air flow in a channel assembly of an infrared air bar in fluid communication with a source of supply air providing a total air flow, comprising:
providing the channel assembly comprising a compartment defined by a bottom having a pair of opposing sides and at least one aperture having an adjustable open area, said compartment comprising an infrared light source for emitting electromagnetic energy, a reflector for reflecting electromagnetic energy emitted by said infrared light source, a lens transmissive to infrared light emitted from said infrared light source, said lens having opposite terminal ends and first and second spaced elongate longitudinal lens edges and a surface defined between said first and second spaced elongate longitudinal lens edges, and at least one elongate longitudinal slot extending between said first lens elongate longitudinal edge and one of said opposing sides of said compartment, wherein a boundary of said at least one slot is defined by said surface of said lens, wherein when said channel assembly is in said air bar in operation in a dryer for floating a web, cooling air flow from said at least one slot is discharged from said compartment parallel to said lens, sweeps said surface of said lens, and provides at least a portion of flotation air for floating the web; and
adjusting said open area of said at least one aperture such that 5 to 40% of said total air flow of said supply air to said air bar enters said compartment through said aperture in said bottom.
9. The method of claim 8 , wherein said open area of said at least one aperture is adjusted such that from 7 to 15% of the total flow of said supply air to said air bar enters said compartment through said aperture in said bottom.
10. The method of claim 8 , further comprising providing an adjustment member positioned in said channel assembly and having at least one adjustment member aperture, and aligning said at least one adjustment member aperture with said aperture of said bottom so as to reduce said open area of said aperture of said bottom.
11. The method of claim 8 , wherein said adjusting is carried out by sliding said adjustment member relative to said at least one aperture of said bottom.
12. The method of claim 8 , wherein said reflector has at least one reflector aperture that is alignable with said at least one aperture having an adjustable open area.
13. The method of claim 12 , wherein the step of adjusting said open area of said at least one aperture comprises adjusting the alignment between said at least one reflector aperture and said at least one aperture.