In 2009, British tech manufacturer Dyson released a product called the Air Multiplier – a fan that was quieter, more power-efficient and safer than others, and to top it all off, it didn’t have any blades.
It sounds like technological witchcraft. So how does it work?
When you think of a fan you probably think of two or more blades attached to a central spinning hub, producing a torrent of air. These blades can slice off a wayward finger, though, and fitting a protective cage to the fan blocks some of the airflow.
The Air Multiplier works differently. Using a combination of clever physics and aerodynamics it “multiplies” the air it sucks in, so uses less energy and generates less noise in the process.
It all starts with air entering through slits at the fan’s base. A small brushless electric motor runs a tiny fan with asymmetrically aligned blades which pushes air through a set of stationary blades that smooth the airflow.
How does a bladeless fan work?
Step1: Air is drawn in
Up to 5.28 gallons of air per second is drawn in by an energy-efficient, brushless motor. A combination of the technologies used in turbochargers and jet engines generates powerful airflow.
Step2: Air is accelerated
Airflow is accelerated through an annular aperture. It passes over a 16° airfoil-shaped ramp, which channels its direction.
Step3: Air is induced
Air behind the Dyson Air Multiplier™ fan is drawn into the airflow, through a process known as inducement.
Step4: Air is entrained
Air around the machine is also drawn into the airflow, through a process known as entrainment, amplifying it 15 times.
What are the advantages of a bladeless fan?
#1 Sleek looking:
It is lovely and you might say a work of Art. Imagine you have such a sleek looking device in your home…#2 no nasty blades to get fingers caught up in, safe. This is good for family with kids.
#3 Blades cause buffeting. This fan has no buffeting.
The blades on conventional fans cause unpleasant buffeting because they chop the air before it hits you. This bladedeless fan amplifies surrounding air, giving an uninterrupted stream of smooth air.
What are the disadvantages of a bladeless fan?
When this device is fully operated, you can have some sense of a mini-vacuum cleaner. But when it’s half operated, it’s really nice and smooth breeze.
#2 Too expensive
A normal fan is $20, but this device costs $300.00. The good news is that some factories in Taiwan and China are manufacturing the similar devices for $50–$65. So hopefully, this retail price will drop to half of it – $150 soon.
Who invented bladeless fan?
In October 2009, James Dyson’s consumer electronics company,introduced a bladeless fan called Dyson Air Multiplier.
However, documents at the Intellectual Property Office, formerly the Patent Office, indicate that Dyson re-submitted its application for a worldwide patent last year after the IPO ruled that its initial design was too similar to the Japanese invention. The Dyson version, “cannot be considered novel or cannot be considered to involve an inventive step”, the initial ruling from the IPO suggested.
Patents expire after 20 years, but even after that date they can not be submitted by a different person or company unless they have been changed or improved upon.
Dyson’s most recent patent applications, which are still pending, have been changed to highlight a key design feature of the Air Multiplier: a Coanda surface. This is the aerofoil ramp over which the air is pushed out of the ring of the fan. Because of the angle of the Coanda surface, the air sucks in surrounding air into the air flow, creating a smooth and powerful blast of air for any office worker using the fan.
Gill Smith, the head of Dyson’s patent department, said: “We wouldn’t dream of denying that the Japanese arrangement and our fan look very similar. The difference is all in the technology. We’ve spent many years developing the Coanda surface. The Japanese version does not have this feature.”
She said that she “absolutely expected” Dyson to be granted a patent for its Air Multiplier. The most recent patent application has not fallen into the “not novel” category that the initial application suffered from.