Bladeless fans were first introduced to the mass market a few years ago by British engineer James Dyson. He is better known for his innovative designs such as the vacuum cleaner without a bag as well as the Dyson airblade; a hand dryer that doesn’t use hot air. Dyson products are renowned for their innovation and have revolutionised their respective markets.
When first looking upon a bladeless fan it will look like no fan you have ever seen without any grilles or visible blades. For this reason you will often be thinking to yourself how does it work. A bladeless fan is simply a circular structure mounted on top of a base; so how can this fan produce a stream of cooling air without any visible moving parts?
The name, bladeless fan, is actually a little bit misleading as whilst there may be no visible blades there is in fact an energy efficient brushless motor in the base of the fan. This brushless motor sucks in as much as 20 litres of air per second, this is the primary source of air flow. Technologies commonly found in turbochargers and jet engines are then employed to accelerate the air before it is passed into the loop amplifier.
The loop amplifier (the circular structure on top of the base) is a hollow structure that acts as a ramp. Air flows inside of the loop amplifier until it is expelled through a 1.3mm annular aperture and then over an aerofoil-shaped blade. This has the effect of creating air flow with 15 times more air than the fan draws in. The reason for the increased air flow is due to some simple physics known as inducement and entrainment. When air is pushed out by the bladeless fan, the air that is behind the fan is also dragged into the airflow through inducement. The air from behind the fan is induced to follow the moving air in the front.
Simultaneously, the air located at the sides and the front of the fan will begin to flow in the same direction due to entrainment. The combined forces of these two effects causes 15 times more air to be expelled than what is taken in. A bladeless fan is as efficient as a conventional fan but has the added benefits of a constant, non-buffeting flow of air.
In recent months there has been a new product introduced, the bladeless fan heater. It uses similar technology to that described above but has the added function of a room heater. It is not commonly known yet but be sure to be on the lookout for them as they increase in popularity.
