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Need help identifying this object

  1. Jul 29, 2010 #1
    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.

    PLxxLl.jpg
     
  2. jcsd
  3. Jul 29, 2010 #2
    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 [Broken]

    just a guess
     
    Last edited by a moderator: May 4, 2017
  4. Jul 29, 2010 #3

    sas3

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    Does it have any numbers on it?
     
  5. Jul 29, 2010 #4
    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.
     
  6. Jul 29, 2010 #5
    Also, the tag on it is for the antique store that I found it in. Nothing useful there either.
     
  7. Jul 29, 2010 #6
    Could be some kind of high power radio station transmitter tube.
     
  8. Jul 30, 2010 #7

    dlgoff

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    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:
    smalltube.jpg

    But it could be a radio transmitter tube:
    BCCOVER235_211.jpg
     
  9. Jul 30, 2010 #8

    uart

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    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.
     
    Last edited: Jul 30, 2010
  10. Jul 30, 2010 #9

    dlgoff

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    You're probably right. A triode not a diode. And the ones I've seen did glow during operation.
     
  11. Jul 30, 2010 #10

    uart

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  12. Jul 30, 2010 #11

    dlgoff

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  13. Jul 30, 2010 #12

    uart

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    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.
     
  14. Jul 30, 2010 #13
    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.
     
  15. Sep 4, 2012 #14
    I'm new to this Forum, but if the object that you have the blue pen under is what you are wanting to ID, then it is an X-Ray tube, probably made by Phillips or Toshiba. I have a very similar looking one on my mantlepiece. The Anode is on the Right and angled at somewhere between 10 and 20 degrees usually to direct the x-rays out at 90 degrees to the axis of the Tube. It should have a small square Tungsten target imbedded in the Copper heatsink/anode assembly. The Cathode is the Chrome electrode on the left and should have a tungsten filament enclosed. Everything is smooth to prevent corona at the rated kV (70 - 110kv depending on the Tube type) These tubes (I used to replace these tubes often) are used mostly in dental or portable equipment like mobile Image Intensifier systems such as Phillips BV25 'C' arm units for surgical procedures.
    Cheers, Warren (retired)
    New Zealand (Middle Earth)
    Electronics Engineer- Medical & Scientific since 1970
     
  16. Sep 4, 2012 #15

    dlgoff

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    Welcome to PF.

    Yep. I posted a X-ray tube so the OP could compare with his tube.

    PLxxLl.jpg
     
  17. Sep 4, 2012 #16

    sas3

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  18. Sep 4, 2012 #17
    Hi, ok, sorry about that. That device above looks a little similar to the Siemens or Philips Switching Tetrodes and Diode's they used in the Xray switching tank to allow high speed switching of the + - 75kVp to allow for Cine Camera operation so as to reduce patient dosage. Is there any brand name or number stamped into the metal base? How many connections are there at the Cathode end?
     
  19. Sep 13, 2012 #18
    It's a thyratron, not an X-ray tube. Basically it can act like a triode-like switch but for very high power levels. I used to use these for switching modulation and power on high power radar magnetrons back in the day.
     
  20. Sep 13, 2012 #19

    Borek

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    Question was already answered - it is a thyratron - and discussion about X-ray tubes is just a side effect of people not reading the whole thread before answering. I am closing the thread, if you have something valuable to add, please contact me using PM.
     
  21. Sep 13, 2012 #20

    Integral

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    I did not need to look on line to ID that. 40yrs ago I worked on a FPS-90 Radar sysytem that used one very much like that. It operated at 400VDC and glowed a beautiful violet around that upper section.

    Thread relocked.
     
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