Strange CFL Failure Mode

Friend of mine still has a couple I believe. I'll get him to check the numbers on them (it's been a long while ago, and I can't remember any more). I'll also see if I can get a coupla piccies of them. The amps in question fed a radio relay network around large areas of the town. They were located in the cellar of a house in the centre of town. Above them on the ground floor, was our workshop, which was always lovely and warm in the winter :-)

On the first floor, above that, was the control room. The radio receivers were located there, and a large patchboard, where the distribution lines were routed, using the big old three pin Bulgin plugs and sockets. There was also a desk console, with an array of meters, which measured 'load'. They were actually measuring audio current going out on the lines.

We used to have fun on a slow Saturday afternoon, when there was no no bosses about, by waiting for an important set of sports results, and then either pulling the plug on a whole area, or switching in the spare receiver, which we had pre-tuned to an offshore pirate radio station. Then wait for the phone to start ringing off the hook down in the office, where some poor part time lady would be located to take any service calls ... :-))

Arfa

Reply to
Arfa Daily
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Thanks, interesting.

However note that Pyrex(R) no longer implies any particular glass type, and in particular, it's no longer borosilicate glass in the US.

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Andrew Gabriel
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Reply to
Andrew Gabriel

Pyrex seems to still be a registered trademark of Corning, at least in the US, though I do see that the use of the Pyrex name has expanded well beyond borosilicate glass, for example, to metal cookware.

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Vic Roberts
http://www.RobertsResearchInc.com
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Reply to
Victor Roberts

Fascinating. I wonder if there are glass furnaces that switch from gas to electrical glass-conductive heating once the glass is molten.

Terry McGowan

Terry McGowan

>
Reply to
TKM

I had forgotten about that, but the answer is yes. See US 2,280,101, issued April 21, 1942. I've put a copy on my web site:

formatting link

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Reply to
Victor Roberts

I do remember seeing somewhere on the Web how to melt a soda bottle (or was it a beer bottle?) in a microwave oven. The glass bottle to be melted required a hot spot pre-heated with a "blowtorch" / "propane torch" or the like, to temperature that I visually estimate to be in the 800's degrees C. It appears to me that soda lime glass that hot achieves conductivity and resistivity suitable for being sufficiently receptive for heating by a microwave oven.

=========================

Disclaimer: I sense that this is adventurous usage of a microwave oven, attempt to do such only at your own risk of damaging your microwave oven or burning down the real estate that such microwave oven is in/on and injuring/killing life forms in/on such real estate including loved-ones, friends and pets by starting a fire.

- Don Klipstein ( snipped-for-privacy@misty.com)

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Don Klipstein

This makes me wonder if the name "Pyrex" "expanded" to glass types other than borosilicate, as opposed to merely being "expanded" to non-glass items.

- Don Klipstein ( snipped-for-privacy@misty.com)

Reply to
Don Klipstein

In the US, Pyrex is currently tempered sola lime glass:

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A factory in Europe also licenses the name, and apparently produces borosilicate glass.

Pyrex is now simply used as a respected brand name, still owned by Corning, but licensed out to whoever wants to use the name. It doesn't imply glass, or any particular type of glass. Corning no longer make anything under the Pyrex name themselves.

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Andrew Gabriel
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Andrew Gabriel

On Thu, 16 Jul 2009 17:38:16 +0100, "Arfa Daily" put finger to keyboard and composed:

I had a bad batch of incandescent light bulbs where the glass separated from the base and fell, or was ejected, onto the floor.

- Franc Zabkar

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Reply to
Franc Zabkar

Please don't say that too loud, lest the electrician's union place a seal and/or lock on every fixture to assure only a licensed union electrician ever changes a lamp. Don't laugh. With all the microcontrollers embedded into everything, it's possible to add lockout codes so only authorized people may restart it, just like you car's "service required" light and reset code.

It's bad enough my TV, monitor, radio and such all say "No user servicable parts inside". Pray, don't let that happen to my home too.

I had a night light bulb shatter, fresh from the package. I'd say that counts as an explosion. I swore off dollar store bulbs ever since.

As to fires, I refuse to use lamps over 100 watts at home, thus avoiding the 300-500 watt halogen torchiere fires that were terribly common for a while. The closest I came to a lamp induced fire was a plastic figurine melting and smoking from being too close to a reflector halogen lamp.

Reply to
Jeff Jonas

it,

Nobody else seems to have brought up that scenario with BPL. How about your refrigerator needing automatic updates and sending usage tracking back to the server, then crapping out because the most recent update no longer supports your model.

Reply to
JB

Sorry for the delayed reply. If the glass is hot enough to soften, it's probably conductive to some extent. However, if surrounded by cooler glass, its resistivity would be too high to matter.

Try this, but be aware that you're dealing with lethal voltages, high enough to jump a short gap (1 cm or so). You, specifically, most likely know how to protect yourself! If in doubt, others should not try this.

Take a [neon] sign or oil burner ignition transformer (the latter is probably better) and arrange temporary electrodes (or use those in a discarded oil burner) to create a steady arc. That arc is like a flame -- it will melt and ignite materials. place a piece of well-insulated glass in the arc (safety glasses!), and let the arc heat the glass. When it starts to glow, or possible a bit sooner, it will become conductive; you'll see the arc divert so current passes through the glass.

As to your power tubes/valves, you might have been lucky.

Regards,

--
Nicabod =+= Waltham, Mass.
Reply to
Nicholas Bodley

Aha! In the experiment I just posted a message about, I was using a glass rod, perhaps for stirring mixed drinks. It might well have been soda-lime glass. While typing, I was wondering about the conductivity of various kinds of glasses. Thank you, kindly, for the enlightenment.

I s.t.r. reading, a long time ago, that Corning Glass used the resistivity of molten glass to keep it hot by passing a lot of current through it. I don't know how it mas heated to begin with, though.

Best regards,

--
Nicabod =+= Waltham, Mass.
Reply to
Nicholas Bodley

That surely describes the case in the experiment I described in a post a few minutes ago.

Best regards,

--
Nicabod =+= Waltham, Mass.
Reply to
Nicholas Bodley

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