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Old 12-18-2010, 11:12 PM   #1
EFaden
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Hey,

Does anyone know how much resistance would be in 1/8" beer lines?... I can only find numbers down to 3/16".

-Eric

 
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Old 12-19-2010, 12:19 AM   #2
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It's probably close to 3.5psi per foot but how would you get it over a barb?
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Old 12-19-2010, 01:59 AM   #3
EFaden
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I have access to some stainless 1/8" barbs. I was thinking of trying 1/8" just to see how it does.

 
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Old 12-19-2010, 07:20 PM   #4
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Give it a try, I'm sure a bunch of us would like to know the outcome.

 
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Old 12-19-2010, 07:29 PM   #5
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I experimented with 1/8" ID polyethylene tubing and I was able to use a 3 foot piece for a decent pour. The problem I have is that all my QB barbs are 5/16".
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Old 07-06-2011, 04:53 AM   #6
ndavid79
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Quote:
Originally Posted by Bobby_M View Post
I experimented with 1/8" ID polyethylene tubing and I was able to use a 3 foot piece for a decent pour. The problem I have is that all my QB barbs are 5/16".
What psi was this at?
Thx

 
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Old 07-06-2011, 11:54 AM   #7
EFaden
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I'd assume around 30.... I have some I am playing with.. Seems to work well
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Old 07-06-2011, 01:39 PM   #8
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Say it takes 10 seconds to pour a pint (16 oz). We can calculate the Reynold's # for 3/16" tubing easily enough at this flow rate and find it's 1562, meaning flow is laminar.

For laminar flow, resistance scales with the diameter^-4.

So if resistance is 1.5 PSI/foot with 3/16 tubing, then it's (3/16)^4/(1/8^4) * 1.5 PSI = 7.6 PSI / ft for 1/8" tubing.

Put more simply, it's a factor of 5. So if you need 10 feet of 3/16", you need 2 feet of 1/8" tubing.

Of course, this is all math, not real life, but I'm an engineer, so I of course wholeheartedly believe it.

(Edit: Fun question! Thanks!)
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Old 07-06-2011, 03:15 PM   #9
EFaden
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Quote:
Originally Posted by shortyjacobs View Post
Say it takes 10 seconds to pour a pint (16 oz). We can calculate the Reynold's # for 3/16" tubing easily enough at this flow rate and find it's 1562, meaning flow is laminar.

For laminar flow, resistance scales with the diameter^-4.

So if resistance is 1.5 PSI/foot with 3/16 tubing, then it's (3/16)^4/(1/8^4) * 1.5 PSI = 7.6 PSI / ft for 1/8" tubing.

Put more simply, it's a factor of 5. So if you need 10 feet of 3/16", you need 2 feet of 1/8" tubing.

Of course, this is all math, not real life, but I'm an engineer, so I of course wholeheartedly believe it.

(Edit: Fun question! Thanks!)
That sounds about right to me... at least for a theoretical approximation.
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Old 02-14-2012, 02:12 PM   #10
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i just purchased some 1/8" ID tubing - I also am wondering where one can find the connection hardware for such a thing?
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