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Cooling Water Silicone Tubing Preferred Values.

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Proud Mary

Thu Jul 30 2009, 07:13AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Iron Man is the tube at the bottom of the picture. Note the water inlet/outlet spiggots at the target end of the tube.

The anode connection is the dark metal spot on the anode end body immediately in line with the water spiggots. There is an identical metal contact button on the other side of the target head.

My night-shirt, on whch the tubes are resting, is not part of the machine, though I suppose I could make using water filter out of it

Steve Conner

Thu Jul 30 2009, 04:20PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Correct me if I'm wrong, but shouldn't this run with the anode grounded and negative HV on the cathode? If the water is for cooling the anode, then I'd expect it to be in electrical contact with the anode.

Herr Zapp

Thu Jul 30 2009, 05:16PM

Registered Member #480 Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644

Harry -

Rather than using the stainless steel worm-gear clamps (which may tend to nick the soft silicone rubber tubing), have you considered the all-plastic ratchet-type clamps?

See:

for an example.

These are non-conductive, easily adjustable without tools, and may have less tendency to damage your silicone tubing.

Regards,
Herr Zapp

Proud Mary

Thu Jul 30 2009, 05:44PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Steve McConner wrote ...

Correct me if I'm wrong, but shouldn't this run with the anode grounded and negative HV on the cathode? If the water is for cooling the anode, then I'd expect it to be in electrical contact with the anode.

Thank you so much, Steve, for drawing this to my attention, because I have worried over it too. In theory of course, one could run it on either sign, and it would be much more convenient from an engineering point of view to run it with an earthed anode. But when you look at the valve base itself, there is nothing about it to suggest it is intended to withstand high voltages. Moreover, as this particular tube has a negatively biased focusing grid (-50V to -250V) it would seem inconceivable that it's pinout could be located within 1 cm of kVp-, without a big stand off at the very least.

If you look at the smallest of my tubes, the end-window transmission-target X-ray tube - which is designed to run on an earthed anode, you see the kVp terminal on a big stand off to keep it clear of the filament terminals - and that is only a mini 20mW tube runs at a maximum of 15kVp, and a tiny 5uA. So for a 25W 50kVp tube like the one in question I would expect to see a very substantial stand-off insulator on the base if it were intended for Va=0 operation.

In any case, now that I have some siclione tubing coming, I can run some acidified water through it and measure the resistance between the water and the anode pins with a high megohmeter (up to 1T) which will solve the matter for sure.

I feel quite sure that the water will turn out to be completely electrically isolated from the anode - remember that we are not talking about heavy hospital machines or industrial radiography units and that the anodes in some of these tubes are hardly more than a scrap of leaf.

MinorityCarrier

Thu Jul 30 2009, 08:26PM

Registered Member #2123 Joined: Sat May 16 2009, 03:10AM
Location: Bend, Oregon
Posts: 312

Harry, check out Proteus, they make flow rate sensors.

Steve Conner

Thu Jul 30 2009, 09:01PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Harry wrote ...

But when you look at the valve base itself, there is nothing about it to suggest it is intended to withstand high voltages. Moreover, as this particular tube has a negatively biased focusing grid (-50V to -250V) it would seem inconceivable that it's pinout could be located within 1 cm of kVp-, without a big stand off at the very least.

What valve base? All I see are two big filament leads.
Also, that -50 to -250 is with respect to the cathode. So if you used negative HV supply, your focusing voltage would be -39950 with respect to ground. So no worries with arcing the base, tremendous worries when it's time to turn the focus pot (with a long dry stick?

) The resulting hassles this would cause with the focus circuit make me think the same as you, that the filament is meant to be the earthy end.

But I don't see a standoff capable of taking 40kV at the anode end of the tube either. The black part is made of metal, right?

klugesmith

Thu Jul 30 2009, 10:46PM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716

I'm tending to side with Steve. Your Iron Man tube has a number of similarities with a standard analytical "X-ray diffraction tube", like:

and

(searched Google Images for x-ray diffraction tube)

In which the anode end is at ground potential, and the filament / negative HV connection is deeply recessed in glass envelope, and the target metal options include iron.
Can you show us a close-up of the perplexing focus electrode connection?

p.s. hey, look at overpriced lot 280368573998 on ebay!
[edit] Did some googling about focus voltage in x-ray tubes. Seems to often be a funny name for tens of volts between hot filament and surrounding cup, providing a digital "control grid" function to rapidly switch the current on and off, e.g. for cinematography. So no need for analog adjustment. In modern designs I could envision a bias supply floating at -HV potential with fiber optic control.

Proud Mary

Fri Jul 31 2009, 02:49AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Klugesmith wrote ...

I'm tending to side with Steve. Your Iron Man tube has a number of similarities with a standard analytical "X-ray diffraction tube", like:

and

Kludge, so far as I understand it they are all analytic tubes as you suggest, though onlythe baby end-window transmission target tube is sepcifically described as a diffraction tool.

Klugesmith wrote ...

Can you show us a close-up of the perplexing focus electrode connection?

It's a bit late to set up the camera now, but if it is important I'll photograph the flying leads tomorrow. But there is really nothing 'perplexing' about the connections at all. The three flying leads are the two filament leads, and the control grid, so there is essentially nothing to see .

The primary function of the grid is to control Ia so that Vf can remain constant, rather than the tiresome old business of having to supply If across 400mV - 4V with high stability.

Iron Man's control grid range is from c. -70V to -250V.

The Russian data sheet is very short and in Cyrillic, which I cannot understand, but the graphs are very clear in any language. There is no graph relating to temperature or water flow.

Plazmatron has done a great job in deciphering much of the data sheet for the baby end-window transmission target tube, so perhaps I can bribe him to see if Iron Man's data sheet has any reference to the water cooling system in it.

Klugesmith wrote ...

p.s. hey, look at overpriced lot 280368573998 on ebay!

Old laboratory throw outs, I s'pose, but someone will buy them for want of anything cheaper and better.

Thanks for all the help and interest. I'm very much learning as I go along, but if I can be saved from any of the more disasterous and costly mistakes, then so much the better.

Proud Mary

Fri Jul 31 2009, 03:22AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Steve McConner wrote ...

What valve base? All I see are two big filament leads.

Sorry for the confusion, Steve. It was very late when I wrote that and I was thinking of a different tube.

In fact, Iron Man has THREE flying leads for f1, f2, and g1, which are being held down against the glass by an elastic band in the picture.

Proud Mary

Fri Jul 31 2009, 03:51AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Iron Man Data Sheets

1249012292 543 FT73566 Iron Man Data Sheet A

1249012292 543 FT73566 Iron Man Data Sheet B

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