The toast comment is because i am up against the clock, miss the next sales cycle and it all ends in tears. I am behind time wise as it is, i have to test the complete system with yeast first. Its a basic test in many ways but as long as i can fully utilize the sugar keep the immobilized yeast happy and keep the production constant, then it should work for what i want.
Ok lets go take the top off the motor unit, i am happy with most the rest. Those pumps are a separate problem, but it isnt difficult. Run them full speed and see what they output, then that gives me an idea what speed i need to get them down to, two will add nutrients or other compounds as needed. so its a case of finding the speed that gives a small amount of solution and then a dead band time for the reactions to complete, take the measurements from the probes (all automatic), if more is needed the pump runs again.
So from that view its a trial and error to see what they push out at full power, then simply adjust the speed to deliver say 0.2ml each cycle. I dont know but my assumption is those kinds of pumps are stepper motor types anyway? I think the drivers however just get the pump to go full speed if you just connect them to the 240V.
So i will use zero cross detect triac, on for ~5 cycles or whatever then off for X, on then off and wait, read and repeat if needed. Not major problem......
The PH controller that comes with the reactor is a problem, it also has the DO probe connection and the PH probe earth connection, no temp compensation and no ref probe, so that leaves a choice of exactly one type of probe
. But in reality I can dump the unit, use something like my Jenway station and take the reading from the serial port.
Dissolved Oxygen, i dont have another probe, i dont think i actually need DO measurement anyway, PH and temperature along with REDOX and TDS readings will be enough to work out DO and some other things anyway.
Sorry this planning bit is boring! I promise the build will be of interest. but I need to get this all straight in my head first.
Variac for 110V for the heat plate, the bottom outer jacket stir mechanism i can deal with, maybe butcher the control for that or even replace the magnet unit and motor with a dedicated magnetic stirrer i have that dosnt heat, I can take the inners out, it takes 240V but drops that to 12V DC.
Micro or several for the different parts, Fram for storing the readings and maybe a pi 3 as the control interface. I dont trust the r pi's, so the micros will be able to do there thing regardless of the pi being on or not. The pi is more a nice easy interface to sort settings and grab the data when i need it.
There is a RTD port, i am leaning towards a RTD for this and not something like a DS sensor. Still open to ideas however.
Small 12V pumps for fluid transfer like the product and empty/fill jobs. plus moving the products etc between the reactors. Simples that one, pwn on brushed DC motors on the pumps.
Level and froth sensors are fairly basic on these, so again not something to think about at the moment. Two of the reactors are all glass no metal at all in them, the other 2/3 are similar reactors to the one i posted a pic of, the others are single unit no outer jackets on, but they have top stiring that is nice and simple 220V, I have the motors and controller for those.
Mai fluid we are dealing with for the cells is Bovine Fetal Serum, standard Biotech stuff, to that is added a mix of nutrient and normally saline! But because the reactors are stainless steel in part, i am not adding saline, instead the saline will be inside the alginate bead itself, so will the organism. Outer bead shell is hardened with chloride, in this case 36% HCl to kill off any stray cells and to give a fairly hard dense outer. then a quick Conc sulphuric acid dip, carbonize any cells the HCl missed, into bicarb to neutralize the Sulphuric. I am hoping for 6 weeks life span from each set of beads.
Worse scenario is cells getting into out and into the nutrient solution, cleaning the product up is hard enough, dealing with cells and cell products on mass is something i want to avoid. No protocols apply directly, but several standard ones are close enough to adapt.
So next post i hope to have pics of this stepper.