Interdimensional Corny Keg ? - Home Brew Forums

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01-02-2013, 07:25 PM   #1
Steely99
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Jan 2013
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I'm fitting out a Igloo ColdMax 100 Quart cooler to take a Corny Keg on the road. As I was playing with the interior dimensions of the cooler (31.5inx13.5inx11in[LxWxH]), giving me 81 quarts of useable volume.

Wanting to know the total volume occupied by the Corny, I plugged in common dimensions:

23"x9"dia

4.5^2*23 = 8 quarts = 4 gallons

Yet the specs on the Corny call it 5 gal capacity.

If the outside of the keg occupies only 4 gallons of volume, but the inside of the keg can hold 5 gallons of volume, is there an interdimensional component to the keg?

I've checked it over a few times. Did I make a mistake somewhere?

01-02-2013, 07:35 PM   #2
rayfound
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You forgot to use pi in your calculations. Also, 8 quarts is only 2 gallons. You're goofed in a couple ways.

Volume of Cylinder = pi (r^2) x length

Volume = pi (4.5in^2) x 23in

Volume = 1463 In^3 / (231 in^3 /Gallon)

Volume = 6.33 gallons

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01-02-2013, 07:43 PM   #3
LandoLincoln

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3.14159*4.5^2*23 = 1463.2 cubic inches.

1463.2 cubic inches is 6.3342 US liquid gallons.

But I think 23" is the height of the keg including the handles, so the actual volume is smaller than 23".

01-02-2013, 07:43 PM   #4
ThatGeekGuy

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Your first error is thinking that 8 quarts = 4 gallons.

Using an online calculator for a tube 9" in diameter by 23" yields a capacity of 6.33 gallons.
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01-02-2013, 07:50 PM   #5
rayfound
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Quote:
 Originally Posted by ThatGeekGuy Using an online calculator for a tube 9" in diameter by 23" yields a capacity of 6.33 gallons.

No cheating allowed.

01-02-2013, 07:56 PM   #6
JonM

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Also, the bottom of the corny is rounded so it's not a perfect cylinder. Calculating the volume of a partial sphere is beyond me, though.
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01-02-2013, 07:58 PM   #7
LandoLincoln

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Quote:
 Originally Posted by JonM Also, the bottom of the corny is rounded so it's not a perfect cylinder. Calculating the volume of a partial sphere is beyond me, though.
Well, that's easy.

1) Fill keg with water
2) Pour out contents and measure

01-02-2013, 08:14 PM   #8
rayfound
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Quote:
 Originally Posted by LandoLincoln Well, that's easy. 1) Fill keg with water 2) Pour out contents and measure
Weigh empty. Fill, weigh full.

01-02-2013, 08:42 PM   #9
JonM

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Elegant in its simplicity.
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