Producing Electrical Energy from Surf: A Cylinder and Turbine

[hisham.i]

Hello,

I was watching national geographic from 1 or 2 weeks, and they illustrated a way to produce electrical energy from surf.
I will try to explain the principle:
1- They brought a cylinder, and attached to it a turbine which is designed to rotate in only one direction independent of the direction of the air.
2- they put the other part in water.
when water height increase, the air inside the cylinder will flow in upward direction, and when the water height decrease the air inside the cylinder flow in downward direction, which causes the turbine to rotate in THE SAME DIRECTION.

I googled to find the name of this turbine which rotates in only one direction independent of the air direction but i didn't find it.

Any body knows its name?
Thanks

 

[256bits]

It has been around for some time. They had a write up in the 80's in a one of the mechanics or science magazines
http://en.wikipedia.org/wiki/Wells_turbine

 

[hisham.i]

Thanks a lot, this what i was looking for :).

Now i will search to find some where to buy a small one of these turbines.