Electronics > Projects, Designs, and Technical Stuff
Potting Compound for High Voltage Tube (X-Ray...)
sixtimesseven:
--- Quote from: HighVoltage on December 04, 2019, 04:49:12 pm ---
--- Quote from: james_s on December 04, 2019, 04:40:44 pm ---You don't want to pot an xray tube. Electrical insulation is only one of multiple functions the oil has. The other major function is cooling, oil circulates via convection and cools the anode, absorbing heat and transferring it to the housing.
--- End quote ---
Very true!
For high voltage insulation that also needs heat transfer for cooling, a silicone based potting is not a good choice.
I would at least watch the temperature closely.
Polyurethane or epoxy can be a much better option.
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Polyurethane / Epoxy can be had with much better thermal conductivity. I've even seen some with added ceramic powders which have great conductivity. However, I wanted to go for a soft material because I was worried about the different temperature expansion coefficients and the stresses on the glas tube. Also that was what seems to work from the commercial examples I found...
sixtimesseven:
--- Quote from: MagicSmoker on December 04, 2019, 04:50:49 pm ---
--- Quote from: james_s on December 04, 2019, 04:40:44 pm ---You don't want to pot an xray tube. Electrical insulation is only one of multiple functions the oil has. The other major function is cooling, oil circulates via convection and cools the anode, absorbing heat and transferring it to the housing.
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Hmm... I assumed that potting was okay for this tube, but after actually looking at the datasheets in the OP is states that this tube is supposed to be immersion cooled.
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Sure, that's the recommended way and probably necessary for continuous operation. However, I do not plan to run continuous and I plan to put a thermal sensor of some description in there to monitor what I get.
Also, as stated building a housing which is oil tight - In particular along the feed troughs and making sure the oil expansion can be compensated is doable but orders of magnitude more complicated. And if I don't have to, why should I bother?
james_s:
Well, give it a try then, just beware of the limitations, there's a reason commercial xray heads invariably are filled with oil or SF6. Watch out for differing expansion coefficients too, I remember someone tried potting some nixie tubes years ago in clear resin and they all broke.
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