Posts by Paradigmnoia

Try drag and drop for pictures from Apple devices. My pad drives me nuts when trying to edit my own posts, never mind attempting images. I revert to my PC to do anything complicated. If Apple put cut-paste functions accessible to the keyboard on devices, I would be very pleased.

I wonder why a lawyer is involved in this request, and more so, why then only up to 50 bucks?
I hope there is no NDA attached to it. G.W.'s silence on this report is...out of character for him.
Thanks again for taking the initiative, especially since you may end up out of pocket a bit for this.

Here is a picture of Levi with a reactor (looks empty) from my files. From "Пархомов_ICCF19_Падуя2015"

Actually, the new exploded diagram for the Lugano coil is not right. The coils are laid out with the the front and rear facing parts conflated.

What I wonder is if MY gets her angst out by posting her frustrations, preventing a stress-related heart attack, or if she is getting more wound up possibly increasing the likelihood of a heart attack

@Urban Eriksson
The surface temperature of an object being heated by a radiant source is related to how poorly it transmits the radiated heat, not directly how powerful the source of heat is. Your test demonstrates this very well. Consider the surface temperature of a quartz IR heat bulb. If the quartz tube was poor at transmitting the heat, then the surface temperature would quickly approach that of the filament inside. It would melt. Most of the heat made by the bulb must pass through the quartz unimpeded, and not heat the surface of the bulb. Therefore the temperature of the bulb, if measured at an IR band that is opaque, is not directly representative of the total power output. If the temperature reading is proportional, then the emissivity epsilon can be lowered fix up the power calculation.

Could not one in theory transmit maybe 100's or even 1000's of W/cm2 of IR in the 0.5 to 2.5 micron band through that nearly transparent portion of the alumina IR band, and it would barely be noticed by the Optris using only the 7 to 14 micron band?

@magicsound,
That is consistent with my tests without a cover tube also. In that case the inner (only) tube is hotter where the coil touches, but glows more in visible light both due to lower conduction from that part of the coil wire that does not make good physical contact, allowing increased incandescence of the hotter wire and also reflecting that light from the tube below where the wire does not make good contact. IR spot tests on the free floating parts of the wire are rather difficult to get, due to the small target size. Instead I moved a thermocouple along the inside edge of the tube to test the brighter and darker spots.

Page 25 of the Lugano report, captions for figures 12a and 12b, briefly discuss the inner glow and coil shadows.

The transparency of the MFMP test device (image above) is unique in that it intentionally has an inner incandescent heat source and yet the outer coil on the backside is visible from the front, in addition to the the forward facing part of the outer coil.
edit: If the front coils visible through the outer alumina are shadows, then what are the back coils?

Does alumina become increasingly transparent to visible light with an increase in temperature? (Up to the point of full incandescence). I have not seen this before. The lack of an air gap between the outer coil and the outer cover in the pictured MFMP device may have something to do with it in that case.

It's like the whole thing is transparent (translucent), inner tube and all, except the inner and outer heater coils.
To visible light anyway.
Neat.

Thanks for that image. That outer coil was imbedded in the outer finned cast material in this version, or is this one of the GS versions?
I can't think of any good explanation for the opposite side coil shadows to show up on the front. If the outer coil is separated from the outer tube by an air gap, Glow Stick style, there may be a way, but it seems unlikely... Reflection from the inside of the outer tube?
Interestingly, the strange backside coil shadows also cause the appearance of the low angle coil loop-crossing heat/light bands. I don't suppose there is an IR image from this test?

Additionally, there is a result from these simulated excess heat experiments that might need some extra work to understand better.
When the outer surface was heated to, for example 500 C, and then the inner heat slowly ramped up in steps, there was no increase in the outer temperature until the inner heater (bulb) was heated enough to exceed the internal temperature reached by heating the outer coil. Perhaps a calorimeter would catch the extra power, but the external temperature was not registering this power increase as an independent increase in temperature. This makes some sense, in that if the inner heater is making less heat than the heat already there, It cannot add more heat. However, it seems odd that the parallel heat does not add anything. Where does the power go?

Sorry. Typed that in a rush.
It is simulated excess heat, using a 150 W light bulb.
For what it is worth, a 500 W bulb used prior to this characterization experiment destroyed the tube almost instantly, then the bulb exploded once it exceeded 800 C, and was barely contained by the coil windings holding most of the tube fragments loosely together. From the point the bulb was turned on, to total destruction in this earlier test, was only about 10 seconds.
Both the 500 and 150 W bulbs operated at almost exactly 600 C in the open air.
In both tests the outer coil was heated to 450 C before powering up the internal heat source.

Thank you for your efforts.

150W excess heat inside tube, showing coil shadows. Note crack forming in the tube next to the TC. The tube failed moments later.
Clearly any powerful exothermic reaction needs to be spread evenly over the tube (in time also), or structural failure is likely due to thermal stresses.

Ecco:

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Do you have larger photos form different angles? I'm curious to see how that works out in practice.

Here is another picture. (The angles are all about the same). You can see the loose wraps a bit better. The internal temperature was 866°C for this picture.

Ecco:

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This shouldn't matter. I just tried replicating this in a 3D program. Result: same orientation whether the camera is located at the front or the back of the tube.
For the wire to appear wound in the opposite direction, it has to be wound in the opposite direction. That is, unless I'm slowly becoming crazy and reality works differently than I previously thought.

Aha, yes. Of course you are correct.

Ecco:

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Very interesting, I've never seen this phenomenon before. Do you have larger photos form different angles? I'm curious to see how that works out in practice.

This occurred in all coils that I made that were originally wrapped around a slightly smaller diameter rod (wood dowel), then transferred to the ceramic. Obviously if the coil is loose on the tube then it won't occur. The more regular the spacing and consistent the diameter of the wraps are, the better this occurs. If the outer ends of the coil are not secured then it might not occur.

Mary

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Of course it is. Where the wires don't glow, heat transfer from the heater to the tube is higher than where the wires have no contact, in effect insulating them from the tube.

I think I effectively said that earlier. But thanks for summarizing.
What is interesting to consider is what the IR camera sees exactly when this happens. The area of the heated, touching ceramic is much greater than the hot "floating" wire, but the floating wire is hotter than the ceramic below it. Then consider this is being viewed through an alumina filter (the outer tube).

Coil crossing heat bands. (Squint and you can see it easier). The tube is hotter where the wires do not glow (movable internal TC measurement).

The upper "lights on" photo is the one to count coils with. The patent application photo is best, though. The IR image is showing an artifact caused by the coil wraps not tightly touching the tube at all points. It is hard to describe properly. The coil as a unit is wrapped around the inner tube in a corkscrew of alternating slightly loose and tight when heated. When the coil cools, the coil will shrink and grip the tube tightly.
The coil shadows are easily made. Just turning off the power will do it, but not for long. Internal heat does it best.
Regarding the orientation of the coils, watch for clues in the photos. Some of them are from behind.

That might not be too clear. If the wire is in air and glowing, it is poorly heating the ceramic. When heat sunk by contact to the ceramic, the wire cannot glow so hot, but the tube gets hotter.