Air Amplifiers

An air amplifier is a mechanical device that uses compressed air to increase the volume and velocity of a stream of air. It works by using the Coanda effect, which is the tendency of a fluid (in this case, air) to adhere to a curved surface and create a negative pressure area behind it.

The basic design of an air amplifier consists of a housing with an inlet and an outlet, separated by a tapered throat. When compressed air flows into the housing, it is directed through the throat to the outlet. This flow creates a low-pressure area behind the throat, which in turn draws ambient air into the inlet. The result is a high velocity stream of air that projects outward from the air amplifier, similar to a fan or blower.

In general, air amplifiers can increase the volume of air flow by a factor of up to 25 times compared to the compressed air input. An air amplifier can significantly boost the airflow volume without a single moving part!  

The amount of volume flow increase produced by an air amplifier depends on factors such as the size and design of the amplifier, the inlet pressure and flow rate of the compressed air, and the ambient conditions of the application.

Air amplifiers offer several advantages over other types of air-moving devices:

As an example, air amplifiers are often used in newer bathroom hand dryers because they are energy-efficient, clean, and can produce a high-velocity air stream without requiring a lot of power. Additionally, they are relatively quiet and can operate for long periods without overheating or wearing out. The air amplifier is typically located inside the unit and works by drawing in air through an intake grille and then using a small high-speed fan to compress and accelerate the air. The compressed air is then forced through a narrow nozzle or slot, which amplifies the air speed and creates a powerful stream of air that can quickly and efficiently dry your hands.

Air amplifiers are also used in a variety of industrial applications, such as ventilation systems, dust removal, drying operations, cleaning, blowing, and cooling.


The Coanda effect is a phenomenon in fluid dynamics where a fluid (such as air or water) tends to follow a curved surface rather than continuing in a straight line. When a fluid flows over a curved surface, such as a wing or a cylinder, it adheres to the surface due to the pressure difference between the fluid and the surrounding air.

The Coanda effect is named after Romanian aerodynamics pioneer, Henri Coanda, who discovered the effect in 1930. Coanda noticed that a jet of fluid from a nozzle attached itself to a nearby flat surface, instead of continuing straight ahead as he had expected.

Image: Cruithne9, CC BY-SA 4.0 <>, via Wikimedia Commons

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