This isn't a complex project, it just has a few rather tricky technical challenges to overcome.
The only one that is still stumping me is emptying the spent grain from the mash / lauter tun. Quite a few have suggested installing a large ball valve, but I am not convinced that would work - has anyone actually done this successfully themselves? There are thousands of grains, probably a hundred thousand particals in a decent sized mash, just not convinced that they would all get flushed out. Others have suggested I accept that some manual labour will be required. Putting the two together would suggest multiple MLT's that I empty out manually could be the go.
This is just part of my thought process, and am sure I will find a way, but the best case senario is that I will have to emply at least one bin. if I do decent sized batches the only difference will be that I will be emptying out one MLT as opposed to one bin - so there is really no difference there apart from the plumbing and electrical connetions. Even then, I could just tip the MTL over (providing flexible tubing and wires and rince it out with a hose connected to the washing machine tap. But how is that easier than automating a big ass geared motor to do the same thing? The big ass geared motor I am thinking of is cat no. YG-2738, has 50kg/cm torque and $35.95 with my trade discount ($45 without individually and I suppose from other posts. a lot cheaper on ebay). I have a lot of trouble trying to stop the 2.1 kg/cm tourque model with my hand around the shaft, and they turn 1/4 inch John Guest valves very well.) So as long as the MLT is mounted at the approximate centre of gravity it should be able to rotate a MLT. The tubes and wires could be looped such that the rotation of the MLT simply unwinds the loop rather than twisting them. And a dedicated garden hose style sprinkler or trigger nossle can be permanently mounted to the MLT to direct it inward, or if a hinged lid is attached to the MLT, the sprayer could be fixed and the large motorised valve can be turned on when the MLT is in the rotated position.
Hmmm, one issue here - The motor will have to be mounted above the centre of gravity when the MLT is full, so above half way up. After sparging, the centre of gravity will be much lower and so much more force will be required. I have done COG addition calculations for certain structures I have designed (7 portable 45 tonne mineral sand processing plants that are towed across the ground when the minerals run out in an area - just wanted to make sure they wouldnt fall over), but torque physics is not my strong point, will have to get out the 1600 page physics bible and learn it. I suppose I can just try it, if it isnt powerful enough find a more powerful one - the hard part is the connection between the motor and the MLT. The other option is to cut a chopping board or metal plate into the shape of a wedge or a piece of pie, where the sharp end of the pie shaped wedge will be fixed securely to the MLT, and grouves cut into the outside curve. In this way the geared motor could have a gear on it or a worm drive to increase the tourque - doubt it would be needed though.
Well if thats the hardest issue I have seen so far, what are these things that "cant be automated"? Seriously, I would like to know!