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Thema: Big bubble forming in doser to reagent tube??

  1. #1
    Registriert seit
    22.07.2017
    Beiträge
    6

    Standard Big bubble forming in doser to reagent tube??

    As seen in attached pictures, there is a bubble forming in the tube connected to the reagent bottle, on the doser side. This bubble forms over a period of about 15 hours. It seems that the reagent is slowly flowing back into the reagent bottle.
    The bubble then gets sucked into the KHD when the next measurement is made, (as can be seen in second picture) obviously resulting in wrong value.
    The tube between the doser connector and the reagent bottle is 7cm long.

    As it stands, I have to prime the reagent doser everyday in order to get correct measurements.

    Also attached picture of my setup. Anything wrong there?

    AirBubble_from_doser.jpg
    AirBubble_to_KHD.jpg
    GHLSetup.jpg

  2. #2
    Registriert seit
    07.07.2013
    Beiträge
    45

    Standard

    I have exactly the same problem

    I thought at first it may be sucking air from the joint where the airline meets the doser, but the seals are very good.

    If your theory is correct I might try lifting the reagent bottle higher. I have the same layout as you with the reagent directly below.

    Very annoying.

  3. #3
    Registriert seit
    22.07.2017
    Beiträge
    6

    Standard Now also micro bubbles.

    So after having to prime the tubes again to get the BIG air bubble out, taking a measurement that was off by 0.1dKH compared to my Hanna tester , 16 hours later I check on the reagent tubes and this is what I see:

    MicroBubbles.jpg


    The BIG bubble is there again and now there are micro bubbles too.

    edit 12/02
    Anyone else have this issue?
    Is it a problem with the reagent forming micro bubbles?
    Is air getting in through the doser 2.1?

    No solution from support team?

    The KH Director is useless to me if I have to prime tubes everyday in order to get a correct measurement. Quicker to test with Hanna
    Geändert von Fishbones (13.02.2018 um 11:29 Uhr)

  4. #4
    Registriert seit
    27.01.2017
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    26

    Standard

    Ive been having exactly the same issue, posted in R2R about it, wonder where there coming from. I even changed reagent bottle in case first one was contaminated and somehow causing bubbles to form in the liquid. I might try a check valve and see if that helps.

  5. #5
    Registriert seit
    07.07.2013
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    45

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    The support team have gone very quiet about this issue .

    It is affecting a lot of users.

    It looks to me that the reagent is aerated , when it passes through the doser pump the micro bubbles burst and make a large bubble that slowly moves up the tube towards the KHD.

  6. #6
    Registriert seit
    18.02.2009
    Ort
    Kaiserslautern
    Beiträge
    7.342

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    Hi

    we are already working on this issue, we didn't want to post before we had final results, assumptions don't help anyone.


    It seems that there are micro bubbles in the reagent, our manufacturer told us that this can happen after temperature swings of the reagent.
    This is very likely in the winter, between storage, transport and your home we have temperature differences of 20°C or more.


    These are the planned actions:

    1. reagent manufacturer tries to get rid of most of the micro bubbles with heating and shaking the warm liquid before shipping, this will reduce the air about 80%

    2. we add a software feature "double-check" (can be disabled): if the KHD measures a suspicious value it does a second measurement, it is very unlikely that a bubble affects 2 measurements in a row


    What can you do now?

    1. keep the reagent tubes as short and as straight as possible

    2. get rid of the micro bubbles: get the liquid a bit warmer than room temp., e.g. get temp. about 30°C on a heater, after that loose the air bubbles by stomping
    No support or warranty issues over PM! Please send PMs to the moderators only if you have general problems with using the forum! Thanks for helping us to keep the support efficient.
    Kein Support oder Reklamationsabwicklung über PM! Bitte senden Sie an die Moderatoren nur PMs bei allgemeinen Problemen mit der Verwendung des Forums! Danke dass Sie uns dabei helfen, den Support effektiv zu gestalten.

  7. #7
    Registriert seit
    27.01.2017
    Beiträge
    26

    Standard

    Thanks Matthias

  8. #8
    Registriert seit
    22.07.2017
    Beiträge
    6

    Standard

    Thank you. I'll get stomping ASAP.

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