Homebrew PCBs

but you need to fully compress the hose.
otherwise the liquid flows back in the gap left open.
would be hard with thick hose to fully compress (and have it expand 
afterwards).

or do you think of a pump that uses one way walves and does not fully 
compress the hose?
(bellow or membrane type)

i just had another idea.
if dry compressed air is availabe it would be easy to make a venturio pipe 
pump.
(the principle of bottom-tank color spraying or water vacuum pump)
is simple, no moving parts, very high pressure, but you need to release the 
air blown in again...
(without propelling fumes out).

stefan



On Wed, 01 Oct 2003 15:37:41 +0200, Markus Zingg <m.zingg@...> wrote:

>> i think your pump principle is like those medical "silicon hose rotrary 
>> pumps".
>> they are used for pumping blood and other liquids.
>> the advantage is the silicone hose can be replaced easily, making 
>> sterilization
>> unneccesary, the expensive pump motor, casing etc. is reused...
>>
>> i have no idea where a rc plane builder may need such a pump (i'm kind 
>> of involved
>> in that now...). maybe for tank refueling on glow engine planes (i only 
>> use electric power).
>
> Yep, tank refueling is what they are used for.
>
>> but i think this is not a pump for spray etching, it it a slow pump.
>
> Would that not change if a motor is used? The tube could have a
> dameter of say 1/2" and this would transport quite a bit of etchant in
> a short tim - no? I can imagine that such a pump could do but then I
> don't have experience with pumps. It just apealed me because they seem
> to be easy to build and - based on their principle of operation they
> of course also would resist the etchant.
>
> Markus
>
>
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