detect melting of wax inside an opaque containers?

dances_wit...@yahoo.com

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Dec 25, 2009, 2:46:21 AM12/25/09

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Now let there be some wax inside an opaque container, which is sitting
in a water bath.

Let the wax be one of those (eg, soywax) whose melting point is below
212 F. And let the water bath get slowly heated up.

It is desired to detect, when all of the wax has become liquid.

Methods?

Greg Neill

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Dec 25, 2009, 9:19:19 AM12/25/09

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Can something clever be done in the interior of the
container? For example, have the liquid wax run into
another cavity, shifting the center of gravity with
respect to the container's geometry.

If the container is cylindrical you could at least
detect when the wax begins to melt by the change in
rotational inertia when the wax body detatches from
the container sides and can rotate independently of
it.

7

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Dec 25, 2009, 11:16:31 AM12/25/09

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dances_wit...@yahoo.com wrote:

Simplest method - use a thermometer, timer and a stirrer

After turning on the heater, when the temperature reaches a certain amount,
inside container, turn the stirrer ON and then it becomes even temperature
throughout the mixture. With stirrer ON, time it, and then you know you have
an even mixture after a fixed period has elapsed.

Uncle Al

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Dec 25, 2009, 11:23:23 AM12/25/09

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Temperature, specific heat vs. latent heat. Internal pressure in a
rigid container or shape change in a non-rigid container caused by
large volume increase on melting. Ultrasound image. Magnetic stirrer
and watch the oscillation smooth out.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz4.htm

Tom Potter

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Dec 25, 2009, 10:54:08 PM12/25/09

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"Uncle Al" <Uncl...@hate.spam.net> wrote in message
news:4B34E6FB...@hate.spam.net...

> dances_wit...@yahoo.com wrote:
>>
>> Now let there be some wax inside an opaque container, which is sitting
>> in a water bath.
>>
>> Let the wax be one of those (eg, soywax) whose melting point is below
>> 212 F. And let the water bath get slowly heated up.
>>
>> It is desired to detect, when all of the wax has become liquid.
>>
>> Methods?
>
> Temperature, specific heat vs. latent heat. Internal pressure in a
> rigid container or shape change in a non-rigid container caused by
> large volume increase on melting. Ultrasound image. Magnetic stirrer
> and watch the oscillation smooth out.
>
> --
> Uncle Al

Considering that several steps would be involved
in order to determine the amount of wax used, the qualities of the
container, etc.

perhaps the best approach would be to use an X-ray machine
like those used at airports,
and detect when there are no lumps in the image.

--
Tom Potter

http://tdp1001.spaces.live.com
http://www.tompotter.us/misc.html
http://webspace.webring.com/people/st/tdp1001
http://notsocrazyideas.blogspot.com
http://tdp1001.wiki.zoho.com
-----------------------------------------------

tadchem

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Dec 25, 2009, 11:32:30 PM12/25/09

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Scanning calorimetry.

Put temperature probe into stirred bath. Connect it to a recorder.
Provide constant voltage to the heater sufficient to raise the bath to
boiling temperature.

Slope of temperature versus time will change when wax starts melting,
It will change again when wax finishes melting.

Tom Davidson
Richmond, VA