ROLL SUPPORT DRYERS

Roll support dryers offer an alternative to flotation dryers when the web or the coating are not conducive to being floated. Roll support dryers offer countless configurations including:

• the use driven or non-driven idler rolls,

• AirBars on one or both sides of the web that are movable to control the rate of drying, 

• the use of non-slip roll coatings, 

• externally mounted bearings, and

• the location of the heated air delivery system on top of or behind the dryer enclosure.

When non-driven idler rolls are used, they are often positioned in an arched configuration with slot nozzles positioned over the rolls to improve web handling by increasing the web friction as it passes over the rolls.

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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.