I guess I'm trying to roll my own version of one of these.
Now I've found this pump online which looks cracking for only £10...but is this the best option for what I'm doing without spending much more at this stage? And how would I go about measuring out a dose? I'm guessing I'll need to use a weighing scale because I don't see that the pump would support measuring ?
If i can give a suggestion, i will suggest you to avoid diaphragm pumps, and use or peristaltic, or also better, gear pumps ... diaphragm pumps works much better with decently high speed movement of the diaphragm and plate valves, thing that is not too much in accord with the phisic of gels and dense fluids
I think that the better solution for similar materials (if slow speed piston pumps cannot be used) is a relatively low speed gear pump (more high density have the gel, more slow rotation works better)
looking at the task at hand.
you can look at the neck of the bottle to see how full it is.
weigh the bottle to know how much weight it has. (test tare weight first)
the motor you linked wants to run at high speed. DC motors have little power at low speed, a stepper has huge torque at low speed and can count revolutions better.
in the old days, you would go to the gas station, tell them how much you wanted, they would fill a glass container that was marked, you saw 5 gallons..... then they drained it into your tank.
no reason you could not full a reservoir (PVC PIPE?) above,
then open the valve and with some compressed air, just empty the lot into the bottle.
ehm ... compressed air forprecisely dispense dense fluids isn't exactly the best way ... a piston pump or a gear pump are normally used for that in vending machines ... gear pump for higher volumes and piston pump for high precision, usually ...
Weight measurement is also ok, if you can prevent that someone touch the bottle while filling (for prevent to alter the weighting)
