Homebrew PCBs

Hi

despite the much better result i still don't get a uniform spray coverage.
(i have spaced the holes 2mm and have "streaks" as far as 12mm apart  
(which is the pitch of the spiral).)
i don't know why it is so uneven.
My guess is there is not enough water inside the tube, and it is thrown to  
one side because it is slightly out of round.
maybe it would be better after all to use a line of holes not a spiral....

However, i have worked out a method to find all parameters:
The fan in the bottom is going to stay, so i only have to determine the  
ideal "ring" on the bottom of the tube restraining the liquid from running  
back out. to see which width is ideal i have cut several rings of thin  
plastic (use hole-cutter in drill press, run reverse for thin plastic). I  
will drill a row of relatively big holes (like 3mm) in the tube, and then  
try the different rings (hot-melt glue is ideal for quick tests). The  
ideal ring width will be indicated by the most/highest holes still  
delivering water.
Additionally this will show me how much cross section of hole the sprayer  
can deliver flow for, and i can then make the small spray holes with a  
total cross section area lower than that value.
Well, that is the theory anyway... ;-)

ST



On Mon, 11 Apr 2005 11:10:25 +0200, Stefan Trethan <stefan_trethan@...>  
wrote:

> SUCCESS!!
> i glued a small "fan" or pump wheel into the bottom, with angeled vanes.
> MUCH more spray at MUCH lower RPM.
> I think that is the right way to go.
> ST