Pipefitters(?) question: assembling a fitting and gauge

[Barfield]

Not really a brewing question, but more of a pipefitters question, applied to my 4-keg keezer.

I would like to build and install a leak detection system inline in my CO2 supply line. The idea is this: place a high resolution digital gauge in the gas line between my tank regulator and multi-tap CO2 regulators. If I suspect a leak, I can turn off the CO2 at the tank and, if there IS a leak, a slow and steady decrease in pressure should be observed on the gauge. (Assuming I'm not pouring beers or actively carbonating a keg, which would obviously show a decrease in pressure, too.)

The reason I'm concerned about this is that I regularly disassemble, clean and reassemble keg posts, pressure relief valves, quick disconnects, gas and beer lines, etc. in my 4-keg keezer. Any time there's a lot of disassembly and reassembly there's a chance to introduce a leak.

I'll need a brass branch "tee" fitting, with 3/8" barbs on two sides and a female 1/8" NPT connection on the third. The digital gauge I'm looking at (Elitech temperature data logger - Leader cold chain industry suppliers) has a stainless, male 1/8" NPT fitting that would mate with the female, brass branch tee. The barbs on the tee would connect inline in my CO2 line.

My question is this, and it's only an aesthetic one: is there any way to insure that face of the gauge and the arms of the tee are parallel as I mate them? Do I need PTFE tape? Dope? Both? If a snug fit makes the parts parallel, is that enough to insure a good seal? Any and all thoughts appreciated!

 

[aeviaanah]

I do what your saying but with the low pressure gauge on regulator. This of course requires me to shut off the cylinder. No need for an additional gauge.

From what I understand brass on brass doesn't require tape or dope. If not brass or worn threads a few wraps of tape will work well. If the gauge doesn't align with a proper tightening, remove and add more tape.

 

[Barfield]

I do what your saying but with the low pressure gauge on regulator. This of course requires me to shut off the cylinder. No need for an additional gauge.

From what I understand brass on brass doesn't require tape or dope. If not brass or worn threads a few wraps of tape will work well. If the gauge doesn't align with a proper tightening, remove and add more tape.

Thanks for the insight. I have a pretty typical taprite dual-gauge regulator (similar to this: 3741-BR). Did you replace the low pressure analog gauge or do you just use it as you describe: turn off the cylinder and observe?

Good to have confirmation about using the tape for alignment. For future reference, sounds like the way to go!

 

[aeviaanah]

Thanks for the insight. I have a pretty typical taprite dual-gauge regulator (similar to this: 3741-BR). Did you replace the low pressure analog gauge or do you just use it as you describe: turn off the cylinder and observe?

Good to have confirmation about using the tape for alignment. For future reference, sounds like the way to go!

No need to replace the gauge. I used the one that came with the regulator. I don't think you need a finer resolution. You'll see the needle drop with a leak. Yes I turn the cylinder off and observe

 

[Barfield]

Thanks! Good to know you'll actually see the drop with the resolution of the stock gauge on the regulator!