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  1. #1
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    flooded evaporator oil return



    Hello everyone.
    A open-type screw ethylene glycol unit.10℃ inlet 0℃ outlet.refrigerating capacity is 4300kW.I want to use flooded evaporator.but I am afraid the oil can't return.The compressor is open-type compressor.and the oil sparator is big enough.
    which is better, flooded evaporator or thermosyphon evaporator.How to resolve the oil return? use auto-oil receiver or injector?




  2. #2
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    Re: flooded evaporator oil return

    take a look at a sabroe skid set up

    http://www.youtube.com/watch?v=V5C03cpbDPg

    and dont laugh at me first video attempt [ I'm certainly no cool Monkey Spanners ]

    LPR, flooded evap and hydraulicly operated oil return injection system

    may suit your needs and you can mimic the design

    R's chillerman
    If the World did not Suck, We would all fall off !

  3. #3
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    hookster is offline Veteran Poster I am starting to push the Mods: of RE
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    Re: flooded evaporator oil return

    Hi Chiller what you got strung all over the PAC in the video? Is it a climacheck system or some such?
    I love the smell of Ammonia in the morning!

  4. #4
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    Re: flooded evaporator oil return

    yeah sort of mate was logging various temps / pressures

    commisioning failed

    kept shutting down intermitently on low lpr level

    turned out during high load the violent vapour rising up the level indicator gave false readings

    cure was baffles fitted to make bubbles smaller

    R's chillerman
    If the World did not Suck, We would all fall off !

  5. #5
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    Re: flooded evaporator oil return

    Hi Joanna, take a look in the link below.

    http://www.parker.com/literature/Spo...060/SD-028.pdf

    Marcos

  6. #6
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    Re: flooded evaporator oil return

    What refrigerant is it running on?

    We are talking big size, or slow moving liquid, if I understand you correctly and you want a 10 kelvin difference between the inlet and outlet of the ethylene glycol in the evaporator?

    I'm not familiar with thermosyphon evaporators, but I have a fair knowledge of flooded evaporators and their operation.

    A tad more information would be nice before I make my judgements.

    I'm guessing we are talking about *****, where the oil rich part will be on top, so I would suggest what we call an "oil boiler" where warm liquid from the pilot receiver passes on one side, and a static level from the evaporator is on the other side.
    Every time the pilot receiver is drained, warm liquid passing through the heat exchanger causes the liquid on the evaporator side to boil, and lift oil up into the suction of the compressor.

    To more easily explain, consider these drawings

    In this first picture we have a basic evaporator, with a surge drum on top... Notice the vertical pipe on the side, this is the oil boiler.

    MMC_KVA.jpg

    In this second drawing I have marked out a few basic things just to be sure

    MMC_KVA_oilret.jpg

    And in this last drawing I have explained the function of the oil boiler.

    oilrect_1_1.jpg


    To be sure that the oil boiler functions properly, it is essential that the refrigerant charge in the system is balanced so that at standstill, with no boiling in the system, the level must be near the level of the sight glass, doesn't need to be in the middle of the glass, but a maximum of 10 cm below the glass is what I have found to be the critical point.

    hope this helps
    -Cheers-

    Tycho

  7. #7
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    Re: flooded evaporator oil return

    4000 odd Kw glycol chiller, would make economical sense to apply ammonia with a large AlfaLaval plate HX and surge vessel above, flooded evap, gravity thermosyphon feed.

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