Homebrew PCBs

right that therm is for what i thought of...


the aquarium pump are really not too strong...
i didn't think about that. maximum pumping height only 3 meters..
(means 0,3 bar, and maybe only a drop a minute volume at this height ;-))


still i think a centrifugal pump is what to go for.
(maybe making more nozzles for more volume but less pressure).
take a plastic pump apart (some cheap underwater garden pump or so).
they have a plastic pumping wheel (and case) - get the cheapest to be sure 
it is plastic.
exchange the shaft with a non-etched material and make it longer.
then use the motor from the original pump to drive the (new) shaft which 
stands out
the top / top of the side of the tank.

these pumps can easily supply the volume, and at this volume also enough 
pressure for a good jet...

st


On Wed, 01 Oct 2003 13:15:01 -0000, Dave Mucha <dave_mucha@...> 
wrote:

> The term is Peristaltic.
>
> "produced by the successive contraction of the muscular fibers of their 
> walls, forcing their contents onwards; as, peristaltic movement. "
>
> This style pump offers dosing or low volume delivery of the fulids in 
> question.   Commercial dishwashers use these for soap.
>
> Not really high pressures, but higher than some other styles.
>
>
> Aquarium pumps can only deliver a very low pressure, nothing near what is 
> needed to use a spray nozzle like the link listed, not even close.  They 
> are designed to move liguids in a tank, not create pressures in a pipe.   
> However, some other spray nozzel would be possible, more of a flooding, 
> dripping than a pressure washing.
>
> IF, chemical action was increased by new etchant and not by pressure, 
> then a fish pump might work.
>
> Small chemical pumps are hard to come by, but you might try one of the 
> professional spray systems for a parts replacement.  Maybe you can get 
> them to send a data sheet so you can figure out what the pump is like ?
>
> Dave
>
>
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> --- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan 
> <stefan_trethan@g...> wrote:
>> @markus:
>>
>> 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).
>>
>> but i think this is not a pump for spray etching, it it a slow pump.
>>
>>
>> what pump i suggest:
>>
>> it is not too hard to build a centrifugal pump.
>> you can look for small aquarium pumps too.
>> if you get a EHEIM pump (look at pc watercooling supplys)
>> you may isolate the permanent magnet with thick laquer and that's
> it.
>> it uses ceramic shaft, all other things are plastic i think (only
> the
>> permanent magnet rotor not).
>>
>> these are very good pumps and i think they would be well suited.
>> (the winding is totally encased in plastic)
>> (i cool my pc with it, so i know it... you can't hear these pumps
> from 1
>> meter away...)
>>
>> another option is to build the pump immersed in the etchant.
>> the shaft goues up to the top and there is a motor mounted.
>> use a plastic shaft or a (expensive) metal which is not etched.
>>
>> would be very easy to build from a small centrifugal pump where you
> simply
>> take the motor out.
>>
>> do not try to use any commercial pump which uses some kind of
> sealing like
>> a stuffing box.
>> the etchant will get through and corrode the motor.
>>
>> the centrifugal pump is not very critical design, only needs a
> balanced
>> rotor.
>> (easiest is taking one from another pump).
>> piston pumps are difficult to keep sealed, with metal in the
> etchant.
>>
>> st
>
>
>
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