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IR, visible and UV of small blow torch flame

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#21 dabateman

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Posted 12 April 2019 - 02:59

View PostAndy Perrin, on 12 April 2019 - 00:11, said:


If this is just a simple butane or propane torch, it's really unlikely to contain any metals. I don't know why any would be needed to make that line anyhow.

Too often, my first gut reactions come from past experiences. I have seen lots of inductivly coupled plasma (ICP) ionization emmission, which takes things to the elemental level. But you may have it. An OH peak makes much more sense.

#22 UlfW

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Posted 12 April 2019 - 06:16

View Postdabateman, on 12 April 2019 - 02:59, said:

Too often, my first gut reactions come from past experiences.

Mine too. I have a friend that did a dissertation about combustion and soot creation processes in flames and have read some parts of the document some years ago. Not my field at all.

Edited by UlfW, 12 April 2019 - 06:18.

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#23 Cadmium

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Posted 12 April 2019 - 07:24

I use to have cats that liked to get under the big burners of my kiln when it was firing.
Attached Image: kilncat_021_16.jpg

#24 JMC

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Posted 12 April 2019 - 08:35

This is a butane gas torch, filled from a little butane aerosol can. As for why the 'OH' peak is high on mine, the spectrometer is setup for irradiance measures, which corrects for the drop off in sensitivity at the extremes of the measurement range. A lot of the spectra you see when it just has the axis labelled as 'intensity' have not had this correction, which would explain why the OH peak looks small on some. Also, I doubt the butane in that aerosol is particularly pure - a bit of water in there with it would lead to a bigger OH peak.

Steve, when I was growing up we had coal fires at home, and one of the fires had a back boiler for the water. In the morning our cat would climb up inside the chimney and sleep on the ledge on top of the boiler because it was nice and warm. We had to check the chimney every day before lighting the fire, to make sure that cat wasn't up there.

Edited by JMC, 12 April 2019 - 10:58.


#25 colinbm

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Posted 12 April 2019 - 15:28

JMC, interesting work......In a previous life I did gas welding as part of my trade.
The hottest part of the flame is not the centre core, but just outside the centre core at its tip.
The inner cone is oxygen.
You can test this by placing a small piece of wood or bare match-stick across the flame & you will see that the two outside edges burn first & leave the centre un-burnt the longest.
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#26 JMC

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Posted 12 April 2019 - 23:05

Hi Colin, yes that ties in with what I was always told about the hottest part of the flame. Nice demo with the wood.

My previous life was playing with plasma. My PhD was on the use of low temperature plasmas to produce metal films. I wish I'd had my UV camera equipment then.

#27 Cadmium

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Posted 14 April 2019 - 07:54

Colin, That is a rather nice demonstration.