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. An air flotation bar, comprising:
a header,
first and second primary discharge slots for discharging fluid for supporting a web;
a channel assembly positioned between said first and second primary discharge slots and comprising an internal compartment containing:
an infrared light source for emitting electromagnetic energy,
a reflector for reflecting electromagnetic energy emitted by said infrared light source, and
a lens having a web-facing surface;
at least one aperture in said channel assembly for introducing fluid into said internal compartment for cooling said infrared light source and said reflector; and
at least one secondary discharge slot configured to discharge said fluid introduced into said internal compartment parallel to said web-facing surface of said lens and to said web;
wherein said first and second primary discharge slots and said at least one secondary discharge slot are configured such that 5% to 40% of total air is discharged via said at least one secondary discharge slot.
2. The air flotation bar of claim 1 , wherein said channel is removable from said bar.
3. The air flotation bar of claim 1 , wherein said first primary discharge slot is a Coanda slot.
4. The air flotation bar of claim 1 , wherein said second primary discharge slot is downstream, in the direction of web travel, of said first primary discharge slot.
5. The air flotation bar of claim 1 , wherein said lens is transmissive to infrared light emitted from said infrared light source.
6. The air flotation bar of claim 5 , wherein said infrared light source radiates directly through said lens to transmit infrared energy to a traversing web.
7. The air flotation bar of claim 5 , wherein said infrared light source radiates infrared energy that reflects off said reflector and through said lens to impart infrared energy to a traversing web.
8. The air flotation bar of claim 1 , wherein the open area of said at least one aperture is adjustable.
9. The air flotation bar of claim 8 , further comprising an adjustment member having at least one adjustment aperture, said member being slidable with respect to said channel to adjust the relative position of said at least one adjustment aperture and said aperture in said channel to adjust the open area of said aperture in said channel.
10. The air flotation bar of claim 1 , wherein said first and second primary discharge air slots and said at least one secondary discharge air slot are configured such that 7% to 15% of total air is discharged via said at least one secondary discharge slot.
11. A web dryer comprising a housing containing a plurality of air flotation bars;
wherein the air flotation bar comprises:
a header,
first and second primary discharge slots for discharging fluid for supporting a web;
a channel assembly positioned between said first and second primary discharge slots and comprising an internal compartment containing:
an infrared light source for emitting electromagnetic energy,
a reflector for reflecting electromagnetic energy emitted by said infrared light source, and
a lens having a web-facing surface;
at least one aperture in said channel assembly for introducing fluid into said internal compartment for cooling said infrared light source and said reflector; and
at least one secondary discharge slot configured to discharge said fluid introduced into said internal compartment parallel to said web-facing surface of said lens and to said web;
wherein said first and second primary discharge slots and said at least one secondary discharge slot are configured such that 5% to 40% of total air is discharged via said at least one secondary discharge slot.