Author Topic: Propane cylinder question  (Read 801 times)

Offline Pitlamp

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Propane cylinder question
« on: August 15, 2019, 05:01:16 pm »
Does anyone know how many litres of propane a 47 kg cylinder contains? (These are the standard large red ones which some caving club hostels use for their cooking & heating gas supply.)

Thanks.

Offline Fulk

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Re: Propane cylinder question
« Reply #1 on: August 15, 2019, 05:11:48 pm »
Apparently you multiply the weight (in kg) by 1.96, so a 47-kg cylinder contains 92 L

Offline Pitlamp

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Re: Propane cylinder question
« Reply #2 on: August 15, 2019, 05:43:32 pm »
Great - thanks!  :thumbsup:

Offline Andyj23UK

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Re: Propane cylinder question
« Reply #3 on: August 15, 2019, 06:16:59 pm »
https://www.elgas.com.au/blog/389-lpg-conversions-kg-litres-mj-kwh-and-m3

the figure quoted above tells you how much LIQIUD is in a cylinder

the table @ website - gives you both the liquid and the gas delivered through the regulator

it - if you have a device that runs for 1 hour on one M3 propane gas - how long will a 47kg LPG tank last  ?

read the caveat carefully :

*Note that these are Liquid to LPG Gas unit conversions
^Note that these are LPG Gas to Liquid unit conversions

Offline Pitlamp

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Re: Propane cylinder question
« Reply #4 on: August 15, 2019, 07:05:57 pm »
Thanks - I ought to have explained that I was trying to compare the price per litre for bottled gas compared with the price per litre for bulk delivery. (Propane in bulk deliveries is sold by the litre). So I guess Fulk's quoted figure is what I want?

Propane must have a pretty low density (compared with, for example, water) if 47 kg of the liquid is 92 litres in volume.

Offline droid

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Re: Propane cylinder question
« Reply #5 on: August 15, 2019, 07:46:07 pm »
It has.
No longer 'Exceptionally antagonistic' 'Deliberately inflammatory'

Offline Burt

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Re: Propane cylinder question
« Reply #6 on: August 16, 2019, 03:40:12 pm »
my elementary physics tells me:

Volume of a cylinder = Pi x Rsq x L

where Pi = 3.1415
Rsq = Square of the radius of the round part
L= length (or height) of the cylinder
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Offline Fulk

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Re: Propane cylinder question
« Reply #7 on: August 16, 2019, 03:53:44 pm »
Well, Burt you're right about the volume of a cylinder; however, I guess that the walls of those things are quite thick, and the external dimensions might not be a true reflection of the internal ones (?).

Offline Madness

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Re: Propane cylinder question
« Reply #8 on: August 16, 2019, 06:55:28 pm »
And don't forget the gas is compressed. Unless you know what it's compressed to you can't work out how much gas it contains

Offline JohnMCooper

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Re: Propane cylinder question
« Reply #9 on: August 16, 2019, 07:21:25 pm »
Quote
And don't forget the gas is compressed. Unless you know what it's compressed to you can't work out how much gas it contains

I thought the L in LPG stood for liquified. It's compressed to liquid form then it doesn't compress any more.

Offline ChrisJC

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Re: Propane cylinder question
« Reply #10 on: August 16, 2019, 07:26:07 pm »
It is in liquid form in the 'gas' bottle. It is not 100% full though, there is a vapour space in there too.
The rule of thumb in a car is that the tank is never more than 80% full, but I don't know the rules for a gas bottle.

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Offline JohnMCooper

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Re: Propane cylinder question
« Reply #11 on: August 16, 2019, 07:28:18 pm »
In order to keep propane a liquid at room temperature (70° F or 21° C), it has to be held in a tank at a pressure of about 850 kPa ie 8.5 bar.

Offline Cave_Troll

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Re: Propane cylinder question
« Reply #12 on: August 19, 2019, 11:51:39 am »
walls of cylinder are probably less than 4mm thick steel