You did great job compiling this library. This was one of the most important sources of my information.
What I was referring to when I wrote that blackening is not necessary, was average envelope temperature of 130C and environment temperature of 30C.
For tube dissipating 25W, calculated thermal radiation from envelope at these temperatures is less than 1W. Of course, for a tube dissipating 100W at envelope temperature of 300C, radiation from envelope (or attached cooler) will be much higher (fourth power of temperature), and blackening will make big difference, exactly as you described.
It seems like tube coolers may be unsuitable for tubes with soft glass envelope for the reason this type of glass has high thermal expansion, and uneven contact with cooler may cause stress cracking. But for hard glass tubes like 813 or EL509 this shouldn't be a problem.
Did you try silicone oil or grease to improve thermal contact?
Love Svetlana too, esp. that I am a native of SPB. Their 6P45S with oversized hard glass envelope and gold-plated control grid is a masterpiece of EL519...
Thank you, it's nice it has actually been read.
While that has been suggested I never tried it, thoughts of grease making its way into the socket and the mess in general, dust accumulation, etc. prevented me; and I plain didn't like what I reckoned just a messy notion. :-(
The temperature of your valve is decreasing very fast, what's next? Room temperature?
Let’s suppose an EL34 (a cold one), Tc=130ºC, Te=30ºC, a mean value for glass ε≈0.9, average envelope area A≈8.64 x 10⁻³ m²
P = ε A σ (Tc⁴ -Te⁴) ≈ 7.9 W
Not near... even worse, by convection it should transfer 118.5 W, or more.
Your valve defies physics… but, what's an order of magnitude among friends?
With all due respect, if you are working in a research for the FDA, please advise us…
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Speaking of gettering: when I had Svetlana St. Pete do up my mods to an existing metal-ceramic triode then-configured as a series reg pass device they were to double the number of continuous-acting 'pill' getters and change the ring around the outside of the heatsink from steel to copper.
When I worked on the KT 90 for David Manley back in the late '80s I had Ei spot weld SAES strip getters to the anode.
The cost in both cases was trivial but in neither case did we get to do life tests.
The War Makers Inc., with Daddy Bush as their 'elected' front man, had to eff over Yugoslavia which, amoung many other things, meant no Yugo' goods into the US for the duration.
In the Svet' case it seems the boys in Huntsville, AL were more interested in flying their 707 back and forth to Moscow than they were in paying their supplier's bills, which severely damaged Svetlana as I understand it.
Then we had the sale of the name 'Svetlana', by them, to New Sensor and the rest was a fast ride down the slippery slope to Nowheresville.
Stupidity . . .
See the attachments
When I worked on the KT 90 for David Manley back in the late '80s I had Ei spot weld SAES strip getters to the anode.
The cost in both cases was trivial but in neither case did we get to do life tests.
The War Makers Inc., with Daddy Bush as their 'elected' front man, had to eff over Yugoslavia which, amoung many other things, meant no Yugo' goods into the US for the duration.
In the Svet' case it seems the boys in Huntsville, AL were more interested in flying their 707 back and forth to Moscow than they were in paying their supplier's bills, which severely damaged Svetlana as I understand it.
Then we had the sale of the name 'Svetlana', by them, to New Sensor and the rest was a fast ride down the slippery slope to Nowheresville.
Stupidity . . .
See the attachments
I have to admit that I erred an order of magnitude in my radiation calculation, and, as a result, underestimated contribution of heat radiation to envelope cooling. The actual proportion of radiation and convection is about 50:50, and blackening of tube cooler is important. Sorry for my mistake, and thanks for correcting me.
200C was the temperature of envelope's hot spot, and 130C the averaged temperature of envelope surface.
200C was the temperature of envelope's hot spot, and 130C the averaged temperature of envelope surface.
Interesting...
It was not sale of the name, it was theft. You don't sell your glorious 100 year old name while still in business. Sorry for straying off-topic.
I applaud your attitude, recognizing an error makes you greater, anyway making a mistake, even orders of magnitude is not so serious, my point is that regarding such a complex problem you cannot assign numbers to all parameters without a solid foundation, this is reckless.
So forget 50:50, 1/15, 130ºC, etc. and I will stop annoying.
two or three layers of thin shiny aluminium cooking foil act as very good mirrors/heat obstructors.
I prefer polished stainless steel. It looks nice, and has poor heat conductivity.
Attachments
As a follow on from post #233, I just checked out:
"Some Aspects of the Thermal Design of Electronic Equipment Operating at 300-500C Environmental Temperature" by James P. Welsh, and published in 1959 IRE Trans on Prod Tech, which is a direct reprint of Welsh's 1958 article in IRE Trans Aero & Nav Electronics, which was presented at 1956 conference on Aero Electronics.
But it has no direct discussion or results from the excerpt clipped by Kohl's 1960 book, so I'll have to look further to find the actual 1958 reference used by Kohl. If anyone can access Part 2. of Elec(tronic?) Manufacturing, (Vol.?) 62, (Dec 1958) and published by The Gage Publishing Co., I'd appreciate knowing.
Bill, would you have a better idea of that Dec 1958 publication, or would you have Welsh's May 1957 report HF-1 053-D-3 on the Thermatron in the Pearl Appendix 1 compendium ?
Ciao, Tim
"Some Aspects of the Thermal Design of Electronic Equipment Operating at 300-500C Environmental Temperature" by James P. Welsh, and published in 1959 IRE Trans on Prod Tech, which is a direct reprint of Welsh's 1958 article in IRE Trans Aero & Nav Electronics, which was presented at 1956 conference on Aero Electronics.
But it has no direct discussion or results from the excerpt clipped by Kohl's 1960 book, so I'll have to look further to find the actual 1958 reference used by Kohl. If anyone can access Part 2. of Elec(tronic?) Manufacturing, (Vol.?) 62, (Dec 1958) and published by The Gage Publishing Co., I'd appreciate knowing.
Bill, would you have a better idea of that Dec 1958 publication, or would you have Welsh's May 1957 report HF-1 053-D-3 on the Thermatron in the Pearl Appendix 1 compendium ?
Ciao, Tim
Here's a generated link by 'WorldCat' which turned up your mentioned article at the U of Calgary here in town: Some Aspects of the Thermal Design of Electronic Equipment Operating at 300-500°C Environmental Temperature (Article, 1958) [WorldCat.org] .
Set yourself up on WC (sorry ), tell it your zip, postal code, whatever, and it'll find an astounding array of reference material for you.
Athough most university libraries will serve their subscriptions to the public, rather than only students, staff and alumni, they do require your personal presence on campus and there's a bit of formality to obtain a day- or a week-long access pass. That done, you are good. to. go.
I have a country mile of lit searches to do the next time can spend a full day at the U of C, and then another two or three integrating it all into the huge library I have spinning here, far, far more than is on my site which represents <1%.
That said, there's a great deal of information bereft fronting HTML here Index of /06_Lit_Archive/14_Books_Tech_Papers here: Index of /06_Lit_Archive/15_Mfrs_Publications and here: Index of /06_Lit_Archive/02_PEARL_Arch/Vol_16
Set yourself up on WC (sorry
), tell it your zip, postal code, whatever, and it'll find an astounding array of reference material for you.Athough most university libraries will serve their subscriptions to the public, rather than only students, staff and alumni, they do require your personal presence on campus and there's a bit of formality to obtain a day- or a week-long access pass. That done, you are good. to. go.
I have a country mile of lit searches to do the next time can spend a full day at the U of C, and then another two or three integrating it all into the huge library I have spinning here, far, far more than is on my site which represents <1%.
That said, there's a great deal of information bereft fronting HTML here Index of /06_Lit_Archive/14_Books_Tech_Papers here: Index of /06_Lit_Archive/15_Mfrs_Publications and here: Index of /06_Lit_Archive/02_PEARL_Arch/Vol_16
It's hard to understand a foreign language, I did not finish reading the topic. My IMHO radiator that the picture is only needed to cool the device and not the lamp. The lamp can be cooled slightly only by blowing the bottom panel, while the terminals are cooled and through them the inside of the lamp.
Sorry for my language.
Sorry for my language.
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Your message gets through. Heat transfer through pins and wires is negligible and does not contribute anything to tube cooling. Reducing glass temperature helps cooling anode, but not very much. Glass should not be allowed to get too hot - it may damage tube by outgassing.
Here's a generated link by 'WorldCat' which turned up your mentioned article at the U of Calgary here in town: Some Aspects of the Thermal Design of Electronic Equipment Operating at 300-500°C Environmental Temperature (Article, 1958) [WorldCat.org] .
Set yourself up on WC (sorry
Athough most university libraries will serve their subscriptions to the public, rather than only students, staff and alumni, they do require your personal presence on campus and there's a bit of formality to obtain a day- or a week-long access pass. That done, you are good. to. go.
I have a country mile of lit searches to do the next time can spend a full day at the U of C, and then another two or three integrating it all into the huge library I have spinning here, far, far more than is on my site which represents <1%.
That said, there's a great deal of information bereft fronting HTML here Index of /06_Lit_Archive/14_Books_Tech_Papers here: Index of /06_Lit_Archive/15_Mfrs_Publications and here: Index of /06_Lit_Archive/02_PEARL_Arch/Vol_16
Wow, a wealth of information! If you could provide subject keyword rather than names, would be much easier to search.
None of this is actually intended to be searched, it's supposed to have .html I don't have time to build in front of it and so, in the case of the numbered articles, is set up in accordance with my own little protocols.
Upshot, you're just going to have to wade through stuff, kinda like I did to find it . . .
Sorry . . .
Upshot, you're just going to have to wade through stuff, kinda like I did to find it . . .
Sorry . . .
OTOH, you might use Google like so:
'your search term here' site:www.pearl-hifi.com
You'll turn up all sorts of things.
'your search term here' site:www.pearl-hifi.com
You'll turn up all sorts of things.
Here's a generated link by 'WorldCat' which turned up your mentioned article at the U of Calgary here in town: Some Aspects of the Thermal Design of Electronic Equipment Operating at 300-500°C Environmental Temperature (Article, 1958) [WorldCat.org] .
Set yourself up on WC (sorry
Hi Bill, unfortunately that article by Welsh is the one I looked at and doesn't have any relevant information wrt Kohl's extract.
This is the reference I'm trying to locate, as it should have more detail about Fig.1 in Kohl's 1960 book. So if anyone can identify that reference in more detail than what was given, I'd be very appreciative.
PS. It is reference 3 in Chapt 14 of Kraus's book which I have, so will also try and see what Kraus has on Monday. And a patent confirms the reference is "Electrical Manufacturing". And it is a monthly formal magazine by Gage Publishing.
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