Homestead mailing list

["WILLIAM JONES" <billj AT harborside.com>]

Don Bowen wrote:
> Those low speed devices are best for such things as pumping water. If 
> you try to gear them up for higher output speed you run into significant 
>gear losses due to the significantly increased load between drive elements.
Oh you bet.  Fortunately you can always match the required torque with the 
available
torque, just by modifying the design of the screw.
> The screw (basically an inclined plane wrapped around a shaft) will move 
> water but you have to take into account losses between the pipe and the 
> edges of the screw.  The screw is used to pump water in India by human 
> power.  A treadle is hooked to the upper end and turned by the feet of 
> the pumpers.  Cheap and easy to use so losses become less important.
It's possible we're talking about apples and oranges.  Are you talking about 
an
"open trough" screw?  The kind I'm familiar with has a spiral hose that can 
develop
very high pressures.  But in this case, it produces a certain proportion of 
compressed
air in addition to water.  If you just waste this compressed air, then the 
losses are
extreme.
Anyway, I'm working on figuring out how best to mount the plastic bottles 
around
the central hub.  They mustn't be punctured in any way, hot glue doesn't hold 
them, and a
giant rubber band isn't very appealing.  Any suggestions would be GREATLY 
appreciated.
Bill