Flow Meter for Detecting Leaks in CO2 Lines?

[EFaden]

Hey All,

I was looking at putting the Dwyer VFA-1 (http://www.dwyer-inst.com/Product/Flow/Flowmeters/VariableArea/SeriesVFA-VFB/Intro) inline just after my primary regulator to help detect leaks. It is similar to the CHI (http://www.chicompany.net/index.php?main_page=product_info&cPath=375_20_312&products_id=1215) but is way cheaper. Any ideas if this will work?...

Basically I just want something to be able to look at and see if there is anything above "0" flow when there should be "0" flow, thus indicating a leak.

-Eric

 

[DakotaPrerunner]

The only thing that comes to mind is that a small leak may not be enough to show up on the flow meter. An easy way to check is hook up an empty keg, put 20 psi on it and then close the valve on the CO2 tank. Check in an hour. If the regulator still shows 20 psi you are leak free.

 

[PintOfBitter]

Most leaks are so small you'll need a very sensitive gauge to see them. In my opinion, much easier to just spray each connection with soapy water and look for the bubbles.

Since you're an experienced brewer, you've got a spray bottle full of Star San sitting around already, though, right? Most handy thing ever.

 

[EFaden]

Most leaks are so small you'll need a very sensitive gauge to see them. In my opinion, much easier to just spray each connection with soapy water and look for the bubbles.

Since you're an experienced brewer, you've got a spray bottle full of Star San sitting around already, though, right? Most handy thing ever.

I actually do have it next to the keg. But apparently I missed a leak or two and drained a chunk of my 20#er. What do you think the flow rate of a little leak like that would be? ... in theory that think detects down to .1 CFH (Cubic Feet per Hour).

 

[PintOfBitter]

Wow that's pretty sensitive. bubble method is more sensitive, but still. I wouldn't trust it as my only detection method, but it would be more data, something we like!

 

[EFaden]

Wow that's pretty sensitive. bubble method is more sensitive, but still. I wouldn't trust it as my only detection method, but it would be more data, something we like!

That's what I figure. I mean it seems like it would work, and it is $30....

 

[Boodlemania]

I'm afraid you'll be disappointed with the performance of your $30 flow meter. The bubble method is indeed more sensitive than the flow meter without the headaches associated with thermal shifts, drafts, etc causing false readings. In my professional life, I use flowmeters that cost thousands of dollars and they're no more sensitive than good ol' soapy water.

DakotaPrerunner has the right idea. A rate-of-decay test will be more accurate than a bubble test, but it takes time as well as a thermally stable environment. I recently did a ROD test on my cylinder, reg, and shutoff valves. Cracked valve to pressurize regulator with shutoff valves closed and noted the pressures on the reg. Checked again 12 hours later and both pressures were the same.

 

[EFaden]

I'm afraid you'll be disappointed with the performance of your $30 flow meter. The bubble method is indeed more sensitive than the flow meter without the headaches associated with thermal shifts, drafts, etc causing false readings. In my professional life, I use flowmeters that cost thousands of dollars and they're no more sensitive than good ol' soapy water.

DakotaPrerunner has the right idea. A rate-of-decay test will be more accurate than a bubble test, but it takes time as well as a thermally stable environment. I recently did a ROD test on my cylinder, reg, and shutoff valves. Cracked valve to pressurize regulator with shutoff valves closed and noted the pressures on the reg. Checked again 12 hours later and both pressures were the same.

That is sad... I guess it was a good idea in theory, just not practice. ... So in order to do the ROD test I should pressurize the whole system and then let it sit for a while to see if the regulator gauges go down? That's the basic idea right? I assume I should disconnect the kegs?

 

[Boodlemania]

That is sad... I guess it was a good idea in theory, just not practice. ... So in order to do the ROD test I should pressurize the whole system and then let it sit for a while to see if the regulator gauges go down? That's the basic idea right? I assume I should disconnect the kegs?

Hey, don't be sad! Nothing to be sad about. If no one tried to think of new approaches or techniques, I'd hate to think about where we'd be. Edison was once asked about his lack of results, to which he replied

"Why, man, I have gotten a lot of results. I know several thousand things that won't work."

Essentially you've got the right idea about ROD. You'll want to pressurize everything you want checked then record and wait. If you disconnect the kegs, you'll also be testing the poppet valve in your connector. Keep that in mind. If you connect the keg, it would have to be empty or the beer will skew the results.

Also keep in mind that the longer you wait, the more sensitive (linearly with respect to time) the test.

To keep from wasting time, however, I would hook up, do the soapy water test first, then without disconnecting anything start the ROD test.

 

[EFaden]

Hey, don't be sad! Nothing to be sad about. If no one tried to think of new approaches or techniques, I'd hate to think about where we'd be. Edison was once asked about his lack of results, to which he replied

"Why, man, I have gotten a lot of results. I know several thousand things that won't work."

Essentially you've got the right idea about ROD. You'll want to pressurize everything you want checked then record and wait. If you disconnect the kegs, you'll also be testing the poppet valve in your connector. Keep that in mind. If you connect the keg, it would have to be empty or the beer will skew the results.

Also keep in mind that the longer you wait, the more sensitive (linearly with respect to time) the test.

To keep from wasting time, however, I would hook up, do the soapy water test first, then without disconnecting anything start the ROD test.

Lol. Thanks for the pep talk. I'll make sure to do the soapy water test first.... Off to do a ROD test.