First, the standard safety disclaimer...
Please, DO NOT emulate my system without the proper safety devices in place! I am knowingly modifying a large pressure vessel and working with 220VAC at high amperage in close proximity to water. A boiler of this size could easily explode with INCREDIBLE energy (the Mythbusters did an episode on exploding water heaters that is almost mind-boggling). I have a safety blow-off valve installed to avoid such dire consequences. The bottom line: high powered electrical devices + water + high energy = potential for disaster. DO NOT TRY THIS AT HOME unless you are very confident and competent with working with all systems/forces involved.
Many of you likely remember my old boiler - a 5 gallon Cornelius keg on its side with a 6000W water heater element installed through the lid. I loved the results, but I HATED that boiler. As with many Cornies, it didn't seal without pressure, so it would routinely leak. I found myself struggling with it on multiple occasions. Also, it only had about two minutes worth of steam output before it needed a few minutes to recover. So, I went back to the drawing board, begged for a couple of 1/2 bbl kegs in the classifieds (thanks, Boston!), and now I have results!
First, I modified a 1/2 bbl straight-sided Sanke keg to accept a 5500W water heater element by welding a 1" FPT stainless lock nut to the bottom (from Bargain Fittings
Then I modified a Sanke spear to accept a 1/2" NPT coupler:
...and attached my old boiler rig (a horrid mish-mosh of brass/copper/bronze/stainless fittings and adapters):
Here's the resulting 1/2 bbl boiler:
I attached the output to another series of fittings that allow fresh water to come into contact with the steam (I call this the "point of use" system):
It got 15 gallons of water up to temp in about an hour:
...and it works like a charm!
Once it was up to temp, I experimented with it for about 10 minutes. The pressure never dropped below 12 psi, even at full output. For reference, the tap water temperature was about 80° F (it's summer in south Texas!).
I was able to achieve a faucet-like pour of 150° F water. When I throttled the water flow rate back a bit, I could achieve a 1 qt/min flow of 170-180° F water, which is easily enough flow of high-temp water for fly sparging (thus eliminating an HLT from my system).
When I was done messing around with my new "toy" (term used quite loosely), I removed the power and opened the valves completely. It off-gassed for well over 10 minutes (and that's with NO INSULATION!).
This will be the heat source for strike water, temperature infusions, and sparge water for brews up to 1/2 bbl in volume. I should even be able to recirculate the mash through the "point of use" portion in a RIMS fashion. I plan on routing both fresh water and a recirculating line to the "point of use" rig. I also plan on routing a steam line directly to a manifold inside the mash tun. That design should afford maximum flexibility to the system.
As it turns out, a friend of mine has been lurking on HBT and reading up on a lot of my DIY stuff. Just today, he called and asked about steam mashing. I told him to come on over and check out the new rig in progress. He's now looking into a pressure cooker for a steam driven five gallon AG system.
As with most of my recent projects, the initial post promises great things, but the end results will likely be a bit delayed. I've gotten really busy with life, work, and the like, so brewing has taken a back seat. This boiler WILL appear again, but it may not be for a little while. My goal is to brew with the new rig by sometime this fall.
A further disclaimer:
Note, this is not necessarily an original idea. kladue uses a very similar system to run his rig. I'm not sure how big his boiler is, but the concepts are much the same. Thanks, kladue, for all the input over the years!