THROUGH-AIR DRYERS

ASI's through-air dryers pull heated air through a porous web material as it travels through the dryer. Through-air drying is designed to dry  a permeable web that is not conducive to flotation drying. Accordingly, the web is supported by rolls, a conveyor belt, or chain. Our design provides an even distribution of air in the machine direction and cross-machine direction to deliver uniform and consistent drying. 

 

To ensure even air distribution across the web, the supply air passes through two distribution plates to create two separate pressure drops that effectively distribute the air flow across the web. A third distributor is located below the web to create a third pressure drop that causes the exhaust air to be evenly removed. The results of these three distribution devices are that the supply and exhaust air enter and exit the web, respectively, in a perpendicular orientation that improves web stability and prevents web wrinkle and disruption. The pressure above and below the web is controlled so that air is being pulled through the web to prevent edge disturbances.

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ASI's AirBars

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AirBar design is one of the most important aspects to dryer performance and choosing the correct AirBar is a critical step in every dryer design. ASI has designed and developed over two dozen AirBars that are tailored to specific drying environments, products, and criteria. AirBar selection is based on multiple process variables, including line tension, web porosity, web weight, temperature sensitivity, coating characteristics, and solvent volatility.

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Our AirBars include:

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• slot nozzles - impingement-style AirBars for high heat and mass transfer applications;

• hole bars - impingement-style AirBars that supply dilution air for slower drying applications;

• airfoils - flotation AirBars that can be mounted above or below the web to provide unparalleled lift or hold-down force and can be used:

  • with low web tensions without web flutter; and

  • for single sided web flotation;

• dual purpose AirBars - ASI's impingement-style slot nozzles combined with a moveable wing to convert to a dilution-style AirBar; and

• BW-style AirBars - flotation AirBars that can float the heaviest of webs and can be mounted above or below the web to provide high heat and mass transfer.