Wednesday, October 14, 2009

Bladeless Fan -- Dyson

Dyson, of the bagless vacuum fame, has launched his latest invention, the bladeless fan. Pretty cool idea, I've posted the video below. The fan has no blades, and as he explains, it's basically an air multiplier. In a nutshell, the fan works by creating a field of negative pressure by moving air across a curved surface. The air initially is drawn into the cylinder base, and then pushed out a slit that runs around the whole "circular frame". The small slit that the air is pushed out of and through accelerates the air much like putting your finger in a garden hose to get the water to move faster or farther does.

As the air is pushed across the curved surface of the fan's ring, the speed of the air above the inner part of the ring is moving faster than the air below the flat, outer part of the ring. This speed differential creates a pressure differential, ultimately producing an area of negative pressure. When you have negative pressure, the air then begins to move because of this pressure differential (think isobars on a weather map that ultimately result in "wind"...)Finally, what you the user ends up feeling is a cylinder of air (whose base is the size of the circular ring...) that moves towards you, versus the traditional way fans work by drawing air towards the blades, then "cutting" the air up and sending it towards you. Supposedly this cylinder of air is more forceful than the "cut" up air that a bladed fan throws at you in an inefficient manner. And once the cylinder starts moving due to the negative pressure field, air "behind the ring starts to also be drawn in and through the ring as well towards the user. Kind of makes sense actually.

It's an interesting concept, and the marketing spin is that it's safe and more powerful. The physics around this design are no different than what generates lift on an airplane wing. Looking for some reviews, but think about it, this guy makes an innovative change to a product whose design hasn't changed in centuries. Pretty awesome. Man I wish I were smart.

From the NYPost