Homebrew_PCBs

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














--- 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