Whirlpool design

[schmogger]

We are planning on adding a whirlpool to our 20bbl system and we are looking for input on designs. I have seen flat bottom WP and also convex bottoms. Our thought is to have a manway on the top to be able to add hops and also clean out trub after the WP is empty. Any input would be greatly appreciated.

[gitchegumee]

I like a slight convex shape with a slight slope to the outlets. Two outlets; one at bottom and one about 30% up the side to keep trub pile undisturbed for the first 70% of knockout. Tangential inlet at 30% up the side. Tangential inlet about 20 degrees offset toward center. Tangential velocity about 5m/s. Height about 70% of diameter. Headspace of 20%. Initial filling is done through the very bottom outlet to prevent oxidation. When the level rises to the tangential inlet, then switch to that. After filling and resting, knock out at fastest rate your heat exchanger allows. Slow down the knockout toward the end to prevent trub pile from breaking. Pretty simple, effective, and inexpensive. Up to you to insulate or not. If you're adding this vessel, then I assume it's because your driving your system to the limit now. So insulation would help recapture more heat that you could use. Not necessary if you only brew once or twice a week. Good luck!

[schmogger]

Thank you Phillip for the detailed options for the whirlpool. One question is why do you prefer the slight convex shape? I am sure there is some science behind the thought that I am unaware of.

[dick murton]

If I am following Philips reasoning, because you use the outlet at the bottom to wash out the trub. You shouldn't be getting into the vessel to dig out - both from a heat and a H&S confined working space point of view. The convex shape simple means the trub will was off more easily to the bottom runoff point. We are only talking about a degree or two from the horizontal, not a huge dome. If the dome is too steep, the trub will slide off during cone formation / wort runoff.

If you leave trub to go cold before washing out, it can set as solid as car tyre rubber. We stripped threads on a nylon geared rotating jet buried in trub at one site when it had set. The trub made a great trampoline though.

[gitchegumee]

As usual...

Dick is spot on with his answer. I like every vessel to drain fast and completely. Having a 3 cm dome in the center of your whirlpool also helps the trub drain a bit better. As I've said, I slow the knockout down considerably toward the end to keep the wort from exiting too quickly and washing out trub. This dome helps collect the clear wort at the circumference, where it drains around and out toward the slope of the tank. I also won't have a mirror finish on the whirlpool bottom. A mill finish helps the trub stay put. Dick is again right with his advice to clean out trub immediately. Well separated trub tends to polymerize into green cement if you do not. Whirlpool design is not an exact science. Everyone has their favorite flavor. I toured a large brewery in Missouri that had many whirlpools of various designs--including anti-clockwise rotation. I was told that none of them was a clear winner. I've had very good luck with the advice I've given, but some of that is technique as well. Please let us know how things work out for you!

[schmogger]

Thank you to Dick and Phillip for your comments. What you both said about the convex bottom was kind of what I was thinking but was not sure. You both are great mentors for many of us who are striving to accomplish half of what both of you have already done. A toast to you both.

[liammckenna]

I might also add that if you're planning a side manway, you want it to be shadowless so as not to disrupt your whirl.

We have a WP with a slightly convex bottom as well. It performs quite well even with the manway design fault. As Philip pointed out, the pump draws from a ring of clear trub free wort at the perimeter of the pile.

We dig the 'green cement' out after it cools for a while through the manway (only a 10 hL system). We manage to get about 95% with a shovel and squeegee. Shovelling and rinsing takes about 10 minutes. This residue goes for compost.

Pax.

Liam

[BreweryTech]

While digging up old posts, I found this discussion and was curious for some clarification. Within the discussion, it is mentioned that a slightly con vexed dome is preferred. Is the dome deeper in the center of the vessel or sticking up towards the top of the vessel? I am assuming based on the term that the dome is pointing upwards.

[Matt Dog]

Yes upwards, or higher in the center. Re-read the posts they explain exactly why.