The Evolution of the Nozzle

In the beginning, when hearing and energy conservation were not a consideration, simple open pipes were used for blow off operations. These are a waste of compressed air, dangerously loud, and potentially injurious. Federal regulations have since been implemented requiring hearing protection from exposure  to sound levels 90 dBA over a period of  8 hours or greater. It also mandates that if an orifice be dead ended against the skin it would not exhibit more than 30 psi.

safety nozzle

Safety Nozzle

Thirty years ago, EXAIR got its start making a more efficient nozzle that was O.S.H.A. compliant. The design sheltered the main air orifice down in a milled groove. The secondary orifice is an annular opening. This provides two functions. By chance if someone could find a way to block the main orifice, there is a secondary path for air to flow. The annular orifice also develops a tube of air surrounding the high velocity main air flow. This interaction deadens the sound level as well as creating a vacuum to draw in surrounding air.

Air Jet

air jet

The next step in the evolution is an air jet which utilizes the coanda effect which is the phenomenon where high velocity air will adhere to a surface. Compressed air is injected through an annular orifice at sonic velocity. The injected air is directed toward the output and creates a vacuum on the opposite end. This vacuum pulls in large volumes of free air and results in a larger volume of air on to the target. If one end or the other is blocked, flow simply reverses at well below OSHA dead ended pressure requirements.

Air Amplifier

air ampSimilar in design concept but in larger configurations is the air amplifier.  They move massive amounts of air which makes them an ideal solution for cooling, ventilating, and for blow off. Two styles were developed. An adjustable style were the annular orifice can manually be adjusted to control air flow and force. The second design has a fixed flow where the annular orifice is established with a patented shim.

Super Air Nozzle


The more recent improvement on the safety nozzle is the Super Air Nozzle. The design concept here is to embed the orifices between fins around the perimeter of the nozzle. This prevents blockage by providing a path fore and aft for air to escape and remain below the OSHA dead end pressure threshold.  The high velocity air also creates a low pressure area drawing in up to 25 times in volume of surrounding ambient air than the volume of compressed air consumed. Sound levels are also greatly reduced.

EXAIR is not done exploring new and improved compressed air products. Product design is customer driven so we welcome your feedback.

Joe Panfalone
Application Engineer
Phone (513) 671-3322
Fax (513) 671-3363

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