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  1. #1
    Join Date
    Aug 2008
    Location
    Hibbing, MN
    Posts
    112

    Bulk Milk Tank Internal Leak

    I have a small dairy farmer who has a refrigerant leak in his bulk tank. This is a short coupled system and there are NO LEAKS in the condensing unit or piping to the bulk tank.

    Against my better judgement, I put in a can of A/C Easy Seal to try to fix the leak, and it didn't work.

    Does anyone have advice on how to locate an internal leak in the bulk tank, and how to cut open the shell to repair it? Also, how do I make it look good after repairing the leak?

    Any advice would be greatly appreciated.

    Steve,
    Genesis Refrigeration

  2. #2
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,645
    What part of the country are you in? What is the brand and size of cooler? There techs out there that specialize in this type of repair.
    I will follow with a phone number.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  3. #3
    Join Date
    Dec 2011
    Location
    New Zealand
    Posts
    2,277
    Before you look for the leak, please confirm that the leak is within the vat.
    Disconnect all piping and pressure the vat circuit only (dry nitrogen), depending upon the make, the max pressure should be 10Bar (150psig)
    leave for a period. If the pressure drops very slightly, then finding the leak without ripping of the all insulation skin, will be almost impossible.
    If a drops quite a bit, then you could use a sonic tester to locate the vicinity of the leak, then remove insulation around that area.
    BEST of LUCK

  4. #4
    Join Date
    Oct 2001
    Posts
    6,966
    even a deep vac test with a micron/welsh pump will ace the tank out if it does below 5000 and keeps dropping over night.. beats humping nitros as a first step... NOTE: if you can't pull below 10K microns there is a leak with anything below 5K being moisture or in your case MILK!!
    "when in doubt...jump it out" http://www.youtube.com/watch?v=U1qEZHhJubY

  5. #5
    Join Date
    Aug 2008
    Location
    Hibbing, MN
    Posts
    112
    Thanks for the replies so far. We are located in Northern MN. I have of course isolated the tank and verified an internal leak. I'm just looking for a procedure to find it and to access it. The tank is seamless stainless steel both inside and out. I'm guessing if I find the leak location, I'll have to cut an access hole in the stainless?

  6. #6
    Join Date
    Oct 2001
    Posts
    6,966
    color trace with nitro to get a general area of the leak..soorry for the micron crap if your on that side of the system with it narrowed down on the cooler side
    "when in doubt...jump it out" http://www.youtube.com/watch?v=U1qEZHhJubY

  7. #7
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,645
    Quote Originally Posted by GenesisRefrig View Post
    Thanks for the replies so far. We are located in Northern MN. I have of course isolated the tank and verified an internal leak. I'm just looking for a procedure to find it and to access it. The tank is seamless stainless steel both inside and out. I'm guessing if I find the leak location, I'll have to cut an access hole in the stainless?
    Typically, techs use stythescope on the inside of the tank with the tank under pressure <250 psi. By listening on the inside surface of the tank, the leak is located. Cut a square foot acces hole on the outside with a small cutoff wheel. Tig weld the leak area if stainless steel (most are). Brand helps because they have traditional areas of leaking. Occasionally the load supporting channel may be involved and the channel may also cutout. Usually the refrigerant supply or returns are involved. Also tig the cut out access back and polish. Better contact techs who do this for a living.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  8. #8
    Join Date
    Aug 2008
    Location
    Hibbing, MN
    Posts
    112
    TB,

    Thank you so much. This is exactly the info I was looking for. Again, thanks.

    Steve

  9. #9
    Join Date
    May 2010
    Location
    Oxford, UK
    Posts
    343
    Done a few of these, i get a local stainless steel tig welder to fix them for me, he used to work for one of the tank manufacturers here.

    https://www.youtube.com/watch?v=5e3wC8frIfo


    One thing i have learned is the weight of milk can seal a leak 100%, it needs to be empty to be sure or left for a few days when it will have been emptied etc.

    https://www.youtube.com/watch?v=LsgfRg0B8zw

    Latest one,

    https://www.youtube.com/watch?v=8kmm_Tcim6w

    Check the oil level in the compressor as they can loose a lot in a short time with this sort of leak.
    Last edited by monkeyspanners; 07-09-2013 at 01:24 PM. Reason: more vids

  10. #10
    Join Date
    Dec 2008
    Location
    NW Iowa
    Posts
    129
    I have found a leak in a surge brand tank a few years back. I used the stethoscope and curt the hole with a cut off wheel. I also had a local guy with a rig welder do th repair. This tank leaked on the evap. Plate on the spot welds. It was pitted. Problem was with this tank, it had another leak two years later in another spot weld. Then last year the milk hauler forgot to vent the tank and sucked it down. Lucky for the farmer as the milk company's insurance paid the 80k for a new tank. Good luck!

  11. #11
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,645
    Quote Originally Posted by refrepairman View Post
    I have found a leak in a surge brand tank a few years back. I used the stethoscope and curt the hole with a cut off wheel. I also had a local guy with a rig welder do th repair. This tank leaked on the evap. Plate on the spot welds. It was pitted. Problem was with this tank, it had another leak two years later in another spot weld. Then last year the milk hauler forgot to vent the tank and sucked it down. Lucky for the farmer as the milk company's insurance paid the 80k for a new tank. Good luck!
    You got to love insurance companies buying bulk coolers.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  12. #12
    Hey did you find the leak , I find you need to charge with nitrogen to at least 15 bar , always make sure you do it when take is empty , if you really struggling get hot wash on the go and see the gauge drop specialy on fullwood Paco , I'll weld 3or 4 of these tanks every wk - Dari kool , muller Paco , laval ,

  13. #13
    Join Date
    Aug 2008
    Location
    Hibbing, MN
    Posts
    112
    Just wanted to bring an update to the original post. We located the area where the tank was leaking. Cut an access in the outer shell and hired a tig welder to fix about a 1/4 inch crack in the cooling jacket on the bottom of the tank.

    The welder worked and worked and worked. The more he welded the more the leak opened up. He said the material was very thin. Finally, he got what looked like a good weld (the bead ended up being over 1 square inch. Put pressure on the tank, and found about 5 leaks where the weld bead interfaces with the jacket.

    The welder we hired has lots of experience working on tanks of all kinds and of all materials, but I'm a little concerned that he keeps melting through the jacket.

    I've used RedEpoxY from Highside Chemicals in the past with 100% success. I'm thinking about trying the RedEpoxY on the pinholes rather than calling the welder back. Any thoughts?
    If God didn't want us to eat animals... He wouldn't have made them out of MEAT.

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