Hi gents
I guess I will start this off by explaining my other hobby, coral :)
I propagate soft corals and trade them all over aus it's heaps of fun and great for the stress levels.
I recently put a new all in one system together based on a constantly changing random flow system
Essentially the tank is fed from 2 pumps that are constantly varying in speed and the algorithm I use keeps each pump independently random which the coral seem to like.
Im using these http://www.fish-street.com/jebao_dct_water_return_pump obdviousley a little weaker then what some of you are running on your stills, but these new DC pumps are crazy
How does 15000lt/H + 5.2mt head @ 150w sound? up to scratch?
These pumps are amazing because the speed can be controlled just like a PWM fan with 1 little wire to an arduino/other MCU
So I guess I should also say I work in a lab and we do a lot of solvent extractions, all our distillation apparatus and rotovaps are cooled using chiller units, they dont have the same kind of energy put into them as a big ol copper still but the low volume chiller systems seem to run hard with a lot of head room. 1 unit we use is about half the size of a bar fridge and runs about 10 small glass columns at the same time (keep in mind the total volume of solvent being distilled even between 10 setups is <1lt) but I dare say it could handle much more.
Now these lab chiller units are basically the same as aquarium chillers which you can pickup off gumtree for $100 lotta the time the thermostat is fucked but that's perfect for us anyway.
here is a picy of an aquarium chiller
So what I have been thinking about is this
Similar to the current standard everyone uses on their plated columns but instead of a valve to control the flow rate through the RC I have replaced this with a variable pump (due to simplicity to control)
So I will use the arduino PID library and some other things to measure the RES temp and RC out Temp and keep the flow rate and water at appropriate levels, could also add controls to adjust reflux etc.
For the moment I didn't really see any use in changing the flow rate on the PC, so it's probably easier to drive separately with another pump
Ill try explain more in a bit just getting this out of my head and down somewhere, also nice to get an opinion or too :)