FLOTATION DRYERS

ASI specializes in flotation dryers that use AirBars to float the web through the dryer without making contact with the web. Depending on the characteristics of the web and the drying process, flotation may be achieved with AirBars above and below the web or only below the web. Using AirBars above and below the web allows for a greater heat and mass transfer coefficient to be attained as compared to single sided air impingement. Importantly, dual sided air flotation allows drying to be accomplished at lower air temperatures and with a shorter dryer as compared to single sided air impingement. This results in a cost effective and energy efficient drying system. Other advantages of flotation dryers include:

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• ability to dry the web from both sides;

• non-contact drying - eliminates the need for conveyors and rolls, reduces maintenance, and avoids marking the web surface;

• ability to operate under a large range of web tensions;

• exceptional web stability - web stability is maintained over a large range of air velocities and web tensions;

• versatile applications - paper, fabrics, foils and plastic films can be dried with varying thicknesses and weights;

• optimizing heat usage - heat usage optimized via air recirculation.

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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.