Results 1 to 7 of 7
  1. #1
    Join Date
    Aug 2007
    Location
    racine, wi
    Age
    67
    Posts
    135
    Rep Power
    17

    vacuum in a recovery cylinder?



    i hope this question isnt as dumb as it sounds, but hear goes,,,

    i have a brand new recovery cylinder, and i pulled a deep vacuum in it. now im working on a sandwhich cooler and i find a leak in the service valve. i tried replacing the core and it still leaks so i set up to evacuate the system for repair.
    the nameplate states that it holds 11 oz of mp39. when i go to recover the refrigerant, i end up with 1.5 oz in my recovery cylinder.
    which brings me to my question...
    it is my understanding that if you have a cylinder with "only" refrigerant in it, it will pressurize to the correct pressure for that refrigerant at that ambient temp. why is it that when i hook my gauges, it still reads a vacuum?
    thanks a bunch,
    mike



  2. #2
    Join Date
    Aug 2003
    Location
    Netherlands
    Age
    49
    Posts
    621
    Rep Power
    21

    Re: vacuum in a recovery cylinder?

    How big is the recycle cilinder?

    11 oz is 311 gram, so on a cylinder that can hold say 28 kg that is not enough to brake the vacuum!
    Last edited by Lowrider; 23-09-2007 at 08:26 PM. Reason: calculation

  3. #3
    Join Date
    Aug 2006
    Location
    england
    Age
    49
    Posts
    3,874
    Rep Power
    46

    Re: vacuum in a recovery cylinder?

    You need enough refrigerant to have liquid refrigerant in the cylinder to get an acurate reading.

  4. #4
    Join Date
    Aug 2007
    Location
    racine, wi
    Age
    67
    Posts
    135
    Rep Power
    17

    Re: vacuum in a recovery cylinder?

    its a standard sized 30lb cylinder. how much refrigerant would you guess it would take to bring it up to the right pressure at 70 deg f?
    thanks
    mike

  5. #5
    Join Date
    Aug 2003
    Location
    Netherlands
    Age
    49
    Posts
    621
    Rep Power
    21

    Re: vacuum in a recovery cylinder?

    Much more then you have in the sandwich cooler!

  6. #6
    Brian_UK's Avatar
    Brian_UK is offline Moderator I am starting to push the Mods: of RE Site Moderator : and general nice guy
    Join Date
    Mar 2001
    Location
    Dorset
    Age
    76
    Posts
    11,192
    Rep Power
    60

    Re: vacuum in a recovery cylinder?

    How much air is in the cylinder that was in your manifold tubes?
    Brian - Newton Abbot, Devon, UK
    Retired March 2015

  7. #7
    Join Date
    Aug 2003
    Location
    Netherlands
    Age
    49
    Posts
    621
    Rep Power
    21

    Re: vacuum in a recovery cylinder?

    The formula to calculate the amount is:

    p*V=n*R*T

    p= pressure in Pa (N/m2)
    V= volume in m3
    n= amount of gas in mol
    R= gasconstant (8,314472 Jk-1mol-1)
    T= absolute Temperature in K


    Let me know what you came up with!

Similar Threads

  1. MP66 & Compressor Overheating
    By Intermez in forum Technical Discussions
    Replies: 111
    Last Post: 13-04-2010, 08:58 PM
  2. Vacuum test
    By Peter_1 in forum Fundamentals
    Replies: 15
    Last Post: 13-10-2006, 09:04 PM
  3. Recovery and vacuum equipment
    By Larry2 in forum Fundamentals
    Replies: 2
    Last Post: 19-07-2006, 12:16 AM
  4. Can I leave a system in a vacuum overnite?
    By kengineering in forum Technical Discussions
    Replies: 15
    Last Post: 17-05-2006, 03:03 PM
  5. Replies: 6
    Last Post: 16-04-2006, 01:27 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •