You'll have to zoom in to really see the detail.
This pen has a blind cap that when loosened, aligns a hole that goes through the top of the pen. This hole is also aligned with a channel leading to the ink reservoir.
The user blows through this hole. Air traveling over the channel creates a Venturi effect, which causes a vacuum in the ink reservoir, filling the pen.
Then a ball float rises to block and seal the channel when the pen is filled.
First off, it's just interesting. Probably not practical.
I can't really imagine that the ball float would really give a good seal, and not allow any ink into the channel.
So whenever the pen is filled, I'd be willing to bet that the user actually blows some ink through the hole and out the top of the pen, probably on your desk, hands, the pen, etc...
Any historians out there know more about this? Did it really work without blowing ink on your desk?
If only you could engineer a slide whistle into it.
Edited by bgray, 17 January 2010 - 20:59.