Managed to elevate the mercury vapour pressure inside a dead Luxten 8W T5 lamp « on: December 11, 2012, 06:14:32 AM » Author: dor123
I have now microwaved a burned out generic Luxten 8W T5 daylight halophosphor fluorescent lamp for 1 min, and analysed its spectrum with my CD-R. After several seconds, I suddenly noted that the mercury lines got brighter and more prominent, while the halophosphors emission remained the same intensity or even reduced in intensity, meaning that the mercury vapour pressure inside the tube, was elevated. As the lamp was very hot, I took it out by a glove. To prevent my mother, my tutor or the hostel crew to know about the experiment, I didn't filmed it. Update: Unfortunately, the lamp lost vaccum after the second try.
« Last Edit: December 11, 2012, 08:32:36 AM by dor123 »		Logged

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	Re: Managed to elevate the mercury vapour pressure inside a dead Luxten 8W T5 lamp « Reply #2 on: December 11, 2012, 02:37:33 PM » Author: dor123
The microwave oven creates a plasma inside the tube by an electromagnetic induction (Like induction lamps). This plasma heats the mercury. Since this plasma is much more powerful (Several hunderds of watts), the mercury excited to much higher energy levels than in normal operation. This cause the lamp to heat very much, causes much more than normal liquid mercury to vapourise, and since not all of the mercury inside the lamp vapourised in normal operation, this may cause an increase in the vapour pressure. Microwaving a 4W T5 lamp inside a 1500W microwave oven, may lead to lamp explosion, because very high energy is constricted to a very small lamp, since all of its 5mg of mercury is completely vapourised, so the pressure rises much more.
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Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the international date format (dd.mm.yyyy).

I lives in Israel, which is a 220-240V, 50hz country.

	Re: Managed to elevate the mercury vapour pressure inside a dead Luxten 8W T5 lamp « Reply #3 on: December 11, 2012, 06:19:16 PM » Author: BG101
I'd be tempted to give it a zap and then try it in a fitting! May help with Philips tubes BG
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	Re: Managed to elevate the mercury vapour pressure inside a dead Luxten 8W T5 la « Reply #4 on: December 15, 2012, 04:02:08 PM » Author: xmaslightguy
Is there any (safe) way to raise the mercury level in a mercury-starved 4-footer (that is otherwize still good) ?
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	Re: Managed to elevate the mercury vapour pressure inside a dead Luxten 8W T5 la « Reply #6 on: December 16, 2012, 01:27:04 AM » Author: xmaslightguy
I do have a heat gun...might have to do a 'test' out on the patio someday (I think the hardest part though would be heating the tube evenly enough so as not to crack it)
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	Re: Managed to elevate the mercury vapour pressure inside a dead Luxten 8W T5 lamp « Reply #8 on: December 17, 2012, 12:38:35 AM » Author: dor123
Why when the mercury absorbed by the phosphors and the glass, it can't be vapourised anymore, in the lamp operating temperature? The mercury still exists on the tube in liquid form only. So why a higher temperature than normal is needed to vapourise the mercury again? Same thing can happen when a fluorescent lamp wasn't used for a very long time, but then the mercury can be vapourised in the lamp operating conditions (Even if it will take several mins for the mercury to vapourise and several tens of hours to reach equilibrium).
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I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the international date format (dd.mm.yyyy).

I lives in Israel, which is a 220-240V, 50hz country.

	Re: Managed to elevate the mercury vapour pressure inside a dead Luxten 8W T5 lamp « Reply #10 on: December 17, 2012, 05:28:07 AM » Author: dor123
Is this actually solve the problem of mercury starvation, so the lamp can do more hours?
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I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the international date format (dd.mm.yyyy).

I lives in Israel, which is a 220-240V, 50hz country.

	Re: Managed to elevate the mercury vapour pressure inside a dead Luxten 8W T5 lamp « Reply #11 on: December 17, 2012, 12:44:15 PM » Author: Medved
Quote from: dor123 on December 17, 2012, 12:38:35 AM Why when the mercury absorbed by the phosphors and the glass, it can't be vapourised anymore, in the lamp operating temperature? The mercury still exists on the tube in liquid form only. So why a higher temperature than normal is needed to vapourise the mercury again? It react with other components, so it is in big part not in liquid form anymore. Once "trapped" in a compound, it can n ot be released anymore. Quote from: dor123 on December 17, 2012, 12:38:35 AM Same thing can happen when a fluorescent lamp wasn't used for a very long time, but then the mercury can be vapourised in the lamp operating conditions (Even if it will take several mins for the mercury to vapourise and several tens of hours to reach equilibrium). The reaction with other components speed up with temperature, so practically at room temperature the reaction practically does not progress, but it goes pretty fast when e.g. overdriven. So with long time stored lamps it only seep between the phosphor particles, so heating it up could release the mercury again. But when it react, the heat does not help anymore, it could only temporary release some extra from metal parts (where it formed amalgams) and (more important) mix it up over the complete tube volume.
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	Re: Managed to elevate the mercury vapour pressure inside a dead Luxten 8W T5 lamp « Reply #12 on: December 18, 2012, 04:22:45 PM » Author: BG101
I find that letting mercury-starved tubes rest for a few days restores some decent output for a while, at least with Philips 6W T5s. However I'm going to test this with one of my Philips tubes and a heat gun (or the oven) to see what happens. BG
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	Re: Managed to elevate the mercury vapour pressure inside a dead Luxten 8W T5 lamp « Reply #13 on: December 19, 2012, 02:49:02 AM » Author: Medved
For the heating up the tube without causing a thermal stress, I would use the hot air baking oven, but do not set it above 100degC. It warm up slowly and the air circulation keep the temperature inside even. Then one should be careful with cool down as well...
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