I just wanted to add in some more info about the misters, since they were the bane of my previous career.
The pressure pot systems are sometimes referred to as "no fog" or "no mist" coolant systems.
The key operating aspect is that the velocity of the air and coolant streams be as close as possible, to reduce pressure/velocity differential where they join, which causes atomization. As long as you have a way to adjust the ratio of air to coolant pressure, you should be able to tune any reasonable combination of orifices to get proper performance.
The problem I encountered with every suction or gravity feed system was that they only really had two settings once the system started to get gunked up: full blast giant fog cloud, or pitiful nonexistent dribble. Constant monkeying around with the needle valves trying to keep them clean enough to allow coolant to pass through while still having some adjustment, gunk growing in the nozzle, in the lines, just a general huge pain. If you adjust them high enough to get a good reliable coolant feed, you're making fog because the pressure differential required for a good feed, and if you adjust them low enough to not make fog and kind of "sputter", the amount of coolant dispersed is a constantly moving target because of crap coming loose in the line, etc.
The reason I'm such a huge proponent of the pressure pot systems is that with the positive coolant pressure, you really don't have and feed troubles, and your output is much more predictable. The reason why this is great, is that you can carefully tune your output so that most of the coolant is vaporized by heat, but just a tiny bit remains to cool the belt through evaporation, but without being enough to fling everywhere.
To change the ratio you can either go dual regulator, or single regulator with an adjustable orifice on the coolant (needle valve, etc.). I personally like dual regulator, because pressure is applied on the upstream side, so there are no needle valves or other complex features to get gummed up downstream from the reservoir.
Fogbuster is the original company that sold these, and there are several others now. I think Fogbuster's patent may have expired.
I plan on making one up this week to get these big flat grinds finished, so I'll try and see if I can scrap together a drawing if anyone is interested.
The pressure systems do use a pressurized canister for the coolant, but I will not make any recommendations there. All I will say is that a DIY version is not hard, but I would not recommend it for anyone that is unfamiliar/uncomfortable working with pressure vessels. These systems do operate at fairly low pressure, but a mistake or failure could put full line pressure on a housing that might fail catastrophically if at high pressure. If you are comfortable with the build, then I strongly encourage DIY, because it will be something like 1/4 to 1/3 the cost of any of the pre-made systems, and will vastly outperform pre-made venturi systems in the same price range.
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