Need help identifying this object

[joshuamc]

Hi. First post, here and I figured you guys would be able to help me out. I found this for sale today at an antiques shop and after a conversation with the owner, I promised I would try and find out what it is and how much it could be worth - so here I am!

Does anyone have an idea on what this could be? Thanks.

http://imgur.com/PLxxLl.jpg

[aks786]

being at medical store, it seems something like X-ray tube

some x-ray tubes photos http://www.lampes-et-tubes.info/p/t2.htm

just a guess

[sas3]

Does it have any numbers on it?

[joshuamc]

I was in a little bit of a hurry, but the only discernible numbering is the 4.2 in red you see on the side, which I was told may be the distance between each of the 4 mounting holes.

The other text says something along the lines of "Reserve Voltage" or something like that.

[joshuamc]

Also, the tag on it is for the antique store that I found it in. Nothing useful there either.

[waht]

Could be some kind of high power radio station transmitter tube.

[dlgoff]

Looks like a diode tube that I've seen used in motor-generator sets. i.e. ac motor to dc generator.

I don't think it's a X-ray tube which would have a gap between the cathode and anode:
http://www.celnav.de/hv/smalltube.jpg

But it could be a radio transmitter tube:
http://www.arselectronics.com/ARSWEB/PH/BCCOVER235_211.jpg

[uart]

Hi. First post, here and I figured you guys would be able to help me out.

I saw something very like that many years ago in a steel mill. It was a type of very high power triode tube (similar to the "valves" in old amplifiers etc) but instead of being a just a vacuum it contained mercury vapour giving it massively more current carrying capability.

It operated with a heated cathode and nearby control grid (like a conventional triode) and it could withstand forward blocking voltage (if the grid was correctly biased) but once you applied a voltage pulse to the grid to start forward-conduction the mecury vapour made it basically flash over and continue conducting until the AC phase voltage reversal. So essentually it was an electron tube equivalent of a modern thyristor (aka SCR).

Cant remember the exact name but it was something like "thyrotron".

Hope that helps.

[dlgoff]

Looks like a diode tube that I've seen used in motor-generator sets.

I saw something very like that many years ago in a steel mill. It was a type of very high power triode tube (similar to the "valves" in old amplifiers etc) but instead of being a just a vacuum it contained mercury vapour giving it massively more current carrying capability.

You're probably right. A triode not a diode. And the ones I've seen did glow during operation.

[uart]

Yep it looks like it is a "thyratron".

See: http://en.wikipedia.org/wiki/Thyratron

[dlgoff]

Yep it looks like it is a "thyratron".

See: http://en.wikipedia.org/wiki/Thyratron
Interesting. The picture says it contains hydrogen.

[uart]

Interesting. The picture says it contains hydrogen.
Yeah the ones I'd seen looked similar but where for low frequency (mains frequency) phase control application (like an SCR) and contained mercury. According to that wiki article the hygrogen ones where for high frequency / fast risetime applications.

[TurtleMeister]

I've seen tubes like this used in electric spot welders. It allows the welder to have variable heat control. It works very much like a lamp dimmer (chopper switch). Most of them have been replaced by the SCR.