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  1. #1
    Join Date
    Aug 2010
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    3,445

    How much refrigerant is left unutilized in exhausted 30 lbs cylinder?

    When all of the liquid is gone but it exists as vapor and the pressure inside equals that of the low-side, it can no longer be utilized to charge.

    Do you just hold these up to do the first part of charging after pulling a vacuum on the system or do you just recover them into recovery cylinder?

    How many ounces of R12 or R22 becomes captive in the cylinder at the end?

  2. #2
    Join Date
    Mar 2012
    Location
    Indiana
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    18
    I recover what is left into 30lb recovery tank I use for virgin refrigerant only.When tank is almost full of virgin refrigerant I will use it when needed.
    I recycle my old tanks at scrap yard or repurpose them.
    Friend of mine makes bells out of tanks and sells at craft shows.

  3. #3
    Join Date
    Nov 2006
    Location
    Southeastern Pa
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    19,210
    Quote Originally Posted by shoodbefishing View Post
    I recover what is left into 30lb recovery tank I use for virgin refrigerant only.When tank is almost full of virgin refrigerant I will use it when needed.
    I recycle my old tanks at scrap yard or repurpose them.
    Friend of mine makes bells out of tanks and sells at craft shows.
    Same here.

    I collect maybe 15 jugs, and recover the vapor. I usually get 10 - 15 lbs, because some jogs retain some small liquid during the busy times of year, and end up coming home to join the ranks until I have time in the winter to do the recovery.
    [Avatar photo from a Florida training accident. Everyone walked away.]
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  4. #4
    Join Date
    Jan 2001
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    8,059
    Zero if you use it for huffing.

  5. #5
    Join Date
    Jun 2011
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    Houston area
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    Quote Originally Posted by corny View Post
    Zero if you use it for huffing.
    True, but the "high" is not as good as it is on a new cylinder.
    The picture in my avatar is of the Houston Ship Channel and was taken from my backyard. I like to sit outside and slap mosquitos while watching countless supertankers, barges and cargo ships of every shape and size carry all sorts of deadly toxins to and fro. It's really beautiful at times.....just don't eat the three eyed fish....

    ¯`·.¸¸ .·´¯`· .¸>÷÷(((°>

    `·.¸¸..· ´¯`·.¸ ¸.·´¯` ·.¸>÷÷(((°>

    .·´¯`· .¸>÷÷(((°>

    LMAOSHMSFOAIDMT

  6. #6
    Join Date
    Apr 2004
    Location
    MN
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    1,828
    I suppose it's too much to be considered "de minimis" per the EPA? We do what shoodbefishing does. Recover into a tank clearly marked Virgin and eventually use it as virgin refrigerant. We have a set of hoses and recovery machine specifically for this task to hopefully avoid cross contamination.
    A Veteran is a person, who at some point in their life, wrote a blank check payable to the United States of America for payment up to and including their life.
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  7. #7
    Join Date
    Jul 2000
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    Guayaquil EC
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    10,458
    A while ago I did a calculation for R22 left in a 30 lb cylinder and came up with 12.5 ounces, which is worth significant dollars these days.

    For those of you with Pro member status, here's the thread:

    http://hvac-talk.com/vbb/showthread.php?t=1053711

  8. #8
    Join Date
    Feb 2011
    Posts
    114
    Quote Originally Posted by icemeister View Post
    A while ago I did a calculation for R22 left in a 30 lb cylinder and came up with 12.5 ounces, which is worth significant dollars these days.

    For those of you with Pro member status, here's the thread:

    http://hvac-talk.com/vbb/showthread.php?t=1053711
    That number seems high to me. I couldn’t find the expansion rate of R-22, but propane is similar enough to R-22 that it can be used as a drop in replacement (usually not legally).

    The expansion rate of liquid propane, when exposed to atmosphere, is 270 times. So 30 lbs divided by 270 is .1111 of a pound. If R-22 expands at a similar rate and the exhausted cylinder is close to atmospheric pressure, then the results should be similar, or about .1111 of a pound. I know that propane is less dense than R-22, and I know that new cylinders are not completely full of liquid, but that is quite a spread. I would have thought the answer would have been less than 2 ounces. Not saying your wrong, but just that it seems high.

  9. #9
    Join Date
    Jul 2005
    Location
    Tulsa
    Posts
    290
    Quote Originally Posted by icemeister View Post
    A while ago I did a calculation for R22 left in a 30 lb cylinder and came up with 12.5 ounces, which is worth significant dollars these days.

    For those of you with Pro member status, here's the thread:

    http://hvac-talk.com/vbb/showthread.php?t=1053711
    that's a significant amount worth recovering...

  10. #10
    Join Date
    Aug 2010
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    3,445
    Quote Originally Posted by doc havoc View Post
    I suppose it's too much to be considered "de minimis" per the EPA?
    Even if it wasn't, with the current cost of HCFC and CFC refrigerants, why would you waste it if its recoverable?

  11. #11
    Join Date
    Feb 2011
    Location
    Grand Prairie,TX
    Posts
    151
    Quote Originally Posted by corny View Post
    Zero if you use it for huffing.
    as teenagers we used to do this. but... a friend of ours died in a"mysterious freon huffing accident" . don't do drugs kids!!


  12. #12
    Join Date
    Jan 2007
    Location
    Stongsville Oh
    Posts
    931
    Many times I leave my reclaimer out then reclaim the refrigerant into the system and I can dispose of the bottle on the sight. Works great!
    ckartson
    I didn't write the book I just read it!

  13. #13
    Join Date
    Aug 2010
    Posts
    3,445
    Since gas fills the entire volume of container, I need to figure out the water capacity of the tank.

    I think I can pull down to 25m torrs, weigh it, then let it fill up with air and weigh again..or suck it up full of water and weigh.

    It looks like air weighs 1.28g per liter and my analytical balance would resolve to 0.01g, so I think I can get a fairly accurate measurement...

    Then I just have to calculate whatever the vapor density is at 90psia (75pisg) for HCFC-22 and CFC-12.

    How illegal would it be to say take 15 cylinders that's down to 75psi and consolidate them into one using the recovery machine?

    I know refilling disposable cylinders isn't exactly kosher, but then you can buy this attachment at Harbor Freight for filling 1 lb propane bottle from barbecue tank.

    As long as you're reasonable with it and don't let it sit around for ten years I don't see a big danger in it.


    The real question is, when they say "net weight 30 lbs" how much of the 30 lbs is usable? I've read that on tooth paste and such, the net weight only accounts for what you can push out. So, if you were to weigh a new toothpaste, empty, cut, wash, rinse and reweigh, the difference is more than net weight stated.

    When R12 is at what it costs now, there's no sense in not recovering what you can.

    I suppose you could even chill one of the empty cylinders on dry ice, then suck in the contents from other cylinders so as not to introduce nastiness from contamination in recovery equipment.

    From icemeister's calculation, you're looking at about one full small can of refrigerant.

    I know that R22 and R12 cylinders look the same size but R22 is 1.21(11.26 liter @ 20C full) and R12 is 1.33(10.25 liter @ 20C full) specific gravity, so, if they're indeed the same tank physically, "how full" depends on each refrigerant. finding the water capacity of the tank would be useful.

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