Flooding the Bok and detection methods

[Maxximus Flavius]

The issue if flooding seems to rear it's ugly head whenever I start a run in my 2" Bokakob. I accept that this is reality with two much heat. The problem for me is finding that sweet spot with a less than sensitive valve on the propane tank. I've been relying on memory of flame size and of course my acute hearing (and yes I have a cute earring as well, with apologies to John Cleese) to detect the bubbling sounds from the column.

But here's an observation. I had a small leak in the column/dome interface, which by happy accident, appeared just before my acute hearing kicked in. This has finally sunk in that maybe there's a minor pressure increase in the boiler and column with the plug of water way up there in the column. How much, I don't know. But certainly measurable.

So here's the plan. I will install a low range pressure gauge, and force a flooding event with straight water. I should be able to prove or otherwise whether this would be a good detection method. I have not used "search is my friend" to see if this has been addressed before.

[stairman]

sure...making a water pressure bomb sounds good to me

[Maxximus Flavius]

sure...making a water pressure bomb sounds good to me

I think you misunderstood what I'm trying to do. My column is open at the top as it should be. The kind of pressures I'm talking about here would be less than the pressure in a toy balloon. That pressure or not, exists if I have a flooding condition during the distilling process. If you think I'm trying to make a water bomb, I'd rather do that than an alcohol bomb.

[DAD300]

Max, having looked at your rig...it is well built.

As to flood detection...I can not only hear my rig flood, I can feel it by touching the column.

Your rig is extremely well insulated...I might suggest running it at least once, without the insulation and checking for flooding. And removing the insulation could actually stop the flooding.

You could have a flash flood occurring from the top down, rather than from the boiler up!

If you're column is packed tight, dropping too much reflux on top of too hot a packing, it can flood from the top down!

There is a glass column video of this on youtube... http://www.youtube.com/watch?v=MHSPTCEp ... qOugBxVY7k" onclick="window.open(this.href);return false;" rel="nofollow
This guy has a lot of videos...this one shows a flash of reflux at the top that can cause flooding.

I eliminated this by monitoring my cooling water and making sure I wasn't Super Cooling my reflux. You only want it cool enough to reflux and nothing more.

Look here about shock cooling http://homedistiller.org/forum/viewtopi ... 15&t=39190

I also use less insulation now around the top! I believe it lets the reflux penetrate further.

[Maxximus Flavius]

Max, having looked at your rig...it is well built.

As to flood detection...I can not only hear my rig flood, I can feel it by touching the column.

Good suggestions. I will investigate further. My column does shake as well when it's flooding. I'm starting to think the centreing ring I have a third way down the column may be an issue. Time to full the packing out.

I'll watch the glass column video.

[ga flatwoods]

You are not overcharging the boiler are you?
GA Flatwoods

[Maxximus Flavius]

You are not overcharging the boiler are you?
GA Flatwoods

I don't think so. I fill it about 3/4 in the pot, with all the dome headspace. The low wines (40%) don't seem to foam much.

[stairman]

understood was just kidding ya!

[Prairiepiss]

The pressures we are talking would be water column pressures. To low for psi.

[Maxximus Flavius]

The pressures we are talking would be water column pressures. To low for psi.

I concur. I pressurized a riveted aluminum aircraft fuel tank some years ago to check for leaks. Even 1 psi would've destroyed it. I used a rubber balloon over the vent hole and slowly introduced air until inflated. It was the only safe way. I will be using a water column to measure the pressures in the boiler/column.

[Maxximus Flavius]

I spent a little time measuring normal pressures inside my setup. I zip tied a 48" vinyl tube to the service column and added water. I found some SS coax fittings that with minor modification work as excellent instrument fittings.


I set up the worse case scenario with a charge of water, full throttle on the burner, the condenser valve full open and the needle valve closed. I got a water column of 5"s. That's a blow your socks off pressure of 0.1806 psi.When I normalized the operating parameters as I normally do during a standard run, the water column stuck at 1" and 0.0361 psi.


I ran out of time to create a flooding issue. That's tomorrow.

[Lester]

Would this low pressure gauge be a good idea to use for setting the heat correctly with a propane burner? I've read several references to "lower the heat to ~1kw" or something like that, but have no way of doing the same with my propane burner.

I have several blood pressure gauges that read in mmHg and after seeing this thread I will definitely give it a try on my boiler...... if only to get better repeatabity at low (whatever that is) heat settings.

Thank you Maxx!