airknife

An air knife is an industrial device that uses a high-velocity sheet of compressed air to blow across a surface, removing liquids, dust, or debris without physical contact. The air is forced through a long, narrow slot, often into a plenum chamber designed to produce a uniform curtain along the length of the knife. This enables a wide, laminar-like air stream to contact moving webs or stationary parts.

Construction typically includes a housing with a slotted outlet and internal flow-straighteners or fins to equalize pressure across the width. Air knives are available as fixed-length units or modular bars that can be mounted above, below, or beside conveyors, rolls, or other processing equipment. Materials are commonly stainless steel or aluminum to resist corrosion and humidity, and some designs incorporate filtration or conditioning features to supply clean, dry air.

Applications are widespread in manufacturing and processing. They are used for drying and cleaning on packaging lines, bottling and canning lines, printing and coating processes, film and foil web handling, electronics assembly, textiles, and metal fabrication. They are particularly valued where contact blowing could contaminate or damage products or where rapid, non-contact air removal is needed on high-throughput lines.

Advantages include non-contact handling, consistent surface drying or cleaning, and potential reductions in moisture or debris without mechanical wiping. They can offer more efficient use of compressed air when properly sized and configured. Considerations include the need for clean, conditioned air, potential noise and energy use, and the ends of long knives causing nonuniform blow-off if not properly designed and installed. Safety measures, such as guards and proper shielding, are advised to protect operators from high-velocity air.