Sight gauge idea -- reducing dead space

I installed a sight gauge from Bargain Fittings in my keggle and really like knowing my exact volume. With the fitting mounted as low as possible, and with the elbow/compression fitting eating up about 2 inches, it doesn't start reading until ~ 3.5 gallons. That's fine for 5 or 10 gallon batches.

So I want to install one on my HLT, which is a 15 gallon aluminum stock pot. Given the diameter of the pot (wider than a keg), even having the sight gauge start reading 2-3" off the bottom could result in not seeing what my volume is until ~ 4 gallons or so. That means wasting propane if I want to use the sight gauge to measure my sparges, since I have to fill the water up higher in the HLT.

So here's my idea: flip the T-fitting upside down, and bend a piece of polycarbonate tubing Pol Style into a U. The lower dotted line shows where the sight glass could start reading then, and the upper one shows approximately where it would be normally.

Any thoughts? Am I missing something here? Obviously the photo is not to scale, and the 'U' would be perpendicular to the fitting -- this was just easier to draw. The comp. fittings are also bigger/cover up more in real life. I am somewhat concerned about heat from the burner melting the gauge. Might have to make a heat shield.

And yes that is MS Paint.

I am not sure I follow you brother. No matter how you bend the poly, the liquid will have to reach a level where it can flow into the tube and from there it's going to seek equilibrium. If your intent is to be able to read the level below the inlet, that won't happen. Once the liquid is below the inlet level all you have done is create a trap in the bend.

He's trying to read as low as the bottom dotted line as opposed to the top dotted line, probably an extra inch or so which could make a difference.

I'm not sure you'll need this though because with an HLT, you always have excess water in there (at least I do) and measure the difference between readings... I have 6 gallons, add need 4 gallons for my MLT so I drain til it reads 2 gallons.

Nah, just run the outlet to the side, not down. That will get the tubing lower without having to pull a complete "U" shape. Having the tubing sit lower than the bottom of the vessel will make it awkward to sit on a level surface. So far the lowest reading I'm able to derive is using a 1/4" NPT compression elbow because it mounts much lower in the pot than a 1/2"NPT and it doesn't require the added height of a standalone straight compression fitting. Unfortunately, they're not cheap.

If you added an extension to the fitting inside the HLT and an elbow aimed down at the extension's end so that the inlet to the sight glass was close to the HLT bottom, your idea would work. As it is, once the water level gets below your existing inlet, the gauge will no longer follow the water level.

Might help, the other way I do things is that I know I have exactly 3 gallons below my sight glass reading. If I am sparging 3 gal or more then I am set. Otherwise if I'm sparging lets say 2.5 gallons (2nd batch sparge) I'll drain down to the sight glass, then measure off 1/2 gallon into a container I keep around, dump that down the drain and I know I have 2.5 gallons to pump into the MLT left.

I tend to be stingy with water when I'm brewing a light-malty beer since I have to buy distilled to cut my water.

ajwillys said:

He's trying to read as low as the bottom dotted line as opposed to the top dotted line, probably an extra inch or so which could make a difference.

I'm not sure you'll need this though because with an HLT, you always have excess water in there (at least I do) and measure the difference between readings... I have 6 gallons, add need 4 gallons for my MLT so I drain til it reads 2 gallons.

Click to expand...

Right, it's really just an efficiency thing... I like to know my volumes all the time, and to do that properly with a normal setup might mean having 12 gallons in the HLT vs. just the 8 or so I need. That's a lot of extra propane (and water, if I'm using distilled) -- has to be heated for the first infusion and then again for batch sparges.

And it's more than an inch diff.. with the compression fitting screwed into the T, it's over 2 inches, which in my pot = gallons.

I think Bobby's idea is a good one. Barely lose any visible gauge space to fittings, but only have to bend the tube 90 degrees. I would use an elbow compression fitting, but that's more $ (already have the straight fitting), and also adds more vertical coverage of the gauge.

AiredAle said:

If you added an extension to the fitting inside the HLT and an elbow aimed down at the extension's end so that the inlet to the sight glass was close to the HLT bottom, your idea would work. As it is, once the water level gets below your existing inlet, the gauge will no longer follow the water level.

Click to expand...

That was my plan at first, but then I realized that would prohibit adding a thermo probe. I understand with this method I will still have some dead space (whatever space is below the inlet), but it's better than having the gauge pointing straight up, the top dotted line in my diagram.

greenbirds said:

Right, it's really just an efficiency thing... I like to know my volumes all the time, and to do that properly with a normal setup might mean having 12 gallons in the HLT vs. just the 8 or so I need. That's a lot of extra propane (and water, if I'm using distilled) -- has to be heated for the first infusion and then again for batch sparges.

And it's more than an inch diff.. with the compression fitting screwed into the T, it's over 2 inches, which in my pot = gallons.

I think Bobby's idea is a good one. Barely lose any visible gauge space to fittings, but only have to bend the tube 90 degrees. I would use an elbow compression fitting, but that's more $ (already have the straight fitting), and also adds more vertical coverage of the gauge.

Click to expand...

Might be able to simply use a racking cane, already has the 90 degree bend.

Those canes are usually acrylic and will get really soft at HLT temps. The polycarbonate is good for 250F.

Ah ok, I thought they canes were polycarbonate. N/M

Well I completed the HLT. My bend on the polycarbonate was a bit messy, but that's ok. Unfortunately when the burner is on full blast, enough heat gets blown out from under the HLT that the polycarbonate softens to the point where I can indent it with my fingernail.

So I devised this heat deflector from a thin piece of stainless steel and a threaded U that just barely fit around the compression fitting for the sight gauge. It looks kinda ghetto, but it works!


Before


Close-up, that's the U fitting hanging from the spigot.


Inside


U fitting attached. Reflection of the heat deflector makes it look confusing. Photo is looking downwards.


After. Ooo shiny. Actually so shiny that it bothers me. Hopefully it dulls after some more brewing.


Side view.

Note the deflector corners rounded off with the Dremel. I have injured myself enough in this hobby to foresee potential hazards

Man! All I can say is you guy really like to brew the hard way!

Well, he got what he wanted out of it and I'm impressed with the follow through. It does appear to be a lot of work for a couple gallons of resolution but, half the fun is screwing with parts.

you could use Pyrex tube as well if you want to put a bend into the sight glass. By using a butane torch to heat the tube till it starts to glow red and then gently make you bend, keeping the tube in the flame, but moving it back and forth to maintain the glow.

I got 4 12mm(close to 1/2 tube) X 24" tubes on ebay for $3 a tube, and i got a 1/2MIPx1/2 tapered flare street 90º and a silicone faucet washer from Ace .

Bobby_M said:

Well, he got what he wanted out of it and I'm impressed with the follow through. It does appear to be a lot of work for a couple gallons of resolution but, half the fun is screwing with parts.

Click to expand...

We see eye to eye on the fun of it. All told, bending the tube, acquiring the parts, and fabricating the deflector took about 90 minutes and $8 in parts.

Pyrex has to be protected in some way but yes, it's a great material for this purpose.