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  1. #11
    Ken Nadvornick's Avatar
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    Quote Originally Posted by E. von Hoegh View Post
    Column separation is the only problem that can occur. Anything else involves breakage of the tube. The easiest way to fix it is to cool the thermometer until all the fluid is in the ball, but it can be problematic when the thing goes down to minus 40.
    If the thermometer has an expansion chamber at the top of the glass column, then careful heating may be an easier way to go.

    I once had an alcohol field thermometer that was subject to rough handling and frequently sustained bubbles (column separation gaps). Carefully holding it above the vents of my Coleman gas lantern for a few moments back at camp always did the trick.

    Ken
    "They are the proof that something was there and no longer is. Like a stain. And the stillness of them is boggling. You can turn away but when you come back they’ll still be there looking at you."

    — Diane Arbus, March 15, 1971, in response to a request for a brief statement about photographs

  2. #12

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    Quote Originally Posted by Ken Nadvornick View Post
    If the thermometer has an expansion chamber at the top of the glass column, then careful heating may be an easier way to go.
    I once had an alcohol field thermometer that was subject to rough handling and frequently sustained bubbles (column separation gaps). Carefully holding it above the vents of my Coleman gas lantern for a few moments back at camp always did the trick.

    Ken
    You're right. I keep thinking mercury and old, but it would be easier for a mercury instrment too, if it has the space at top. It's also usually easier to find enough heat, rather than extreme cold.

  3. #13

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    Here are the instructions for the Kodak Type 3 Process thermometer (the mercury version), with advice on how to fix column separation.


    Click image for larger version. 

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  4. #14
    Ken Nadvornick's Avatar
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    Quote Originally Posted by Etr420 View Post
    Here are the instructions for the Kodak Type 3 Process thermometer (the mercury version), with advice on how to fix column separation.
    This is the thermometer that is used as my darkroom standard. I even calibrate my Hass Intellifaucet against it. It's a beautiful instrument.

    Ken
    "They are the proof that something was there and no longer is. Like a stain. And the stillness of them is boggling. You can turn away but when you come back they’ll still be there looking at you."

    — Diane Arbus, March 15, 1971, in response to a request for a brief statement about photographs

  5. #15

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    Quote Originally Posted by E. von Hoegh View Post
    Column separation is the only problem that can occur.
    I didn't mention another problem as it is rather rare. There is a small chamber or expansion spacer at the top of most thermometers. I have had liquid become trapped here. Some might lump this with column separation but it is not quite the same and results in a different error from true column separation. The thermometer will read lower than the actual temperature.
    Last edited by Gerald C Koch; 09-24-2013 at 07:58 PM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

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  6. #16
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    I took a closer look at the thermometer last night and as you probably would have guessed there was a break, some fluid was stuck up at the very top of the tube. I heated it up and reconnected that bit, now it is as it should be. Thank you everyone.

  7. #17
    AgX
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    Column seperation is not the only issue with capillary Thermometers though:

    The height to which the thermometer has to inserted is of importance for precision metering.
    With this in mind the ambient temperature is of importance too.
    Precicision thermometers have a mark or such to indicate the level of immersion at room temperature.

  8. #18

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    Well, if it occurs again you can schedule a trip to the top of Mt. Washington NH this February. -40 ought to be easy enough to come by.

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