Massive old vacuum tube, anyone know what it is? - Page 1
Forum section: electronics / general

author: macona
author_rank: Regular Contributor
timestamp: July 12, 2021, 11:46:50 am
content: Picked up this old vacuum tube, its rather large. I think it might be a diode, look like 3 terminals, the base, ring, and what I am guessing is the anode. The base and ring are electrically connected together with a very low resistance so I think that is the heater. The "anode" is hollow so I am guessing water was flowed though it to keep it cool, or maybe just for surface area and save on weight and material.I think the getter pump on the side was added, this came from a glass display at a local university.Anyone seen anything like it? The cutting mat it is on is 1" increments and 1/2 squares. So about 21" longOld vacuum tubebyJerry Biehler, on Flickr

author: gbaddeley
author_rank: Regular Contributor
timestamp: July 12, 2021, 12:21:38 pm
content: Thyratron or Mercury Rectifier? A Triode of this size would have a ceramic or metal case, not glass.

author: Stray Electron
author_rank: Super Contributor
timestamp: July 12, 2021, 01:38:44 pm
content: A rectifier tube would be my guess. Look closely and see if you don't see some tiny drops of mercury in it.

author: amyk
author_rank: Super Contributor
timestamp: July 12, 2021, 01:41:02 pm
content: My guess is something for radar use.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 12, 2021, 03:18:37 pm
content: What's the extra bulb thing, is that kind of behind, is it really connected..?A few more angles also showing inside the electrode structure maybe, might be informative.Tim

author: LaserSteve
author_rank: Super Contributor
timestamp: July 12, 2021, 07:04:29 pm
content: Mousey Grey at the glass to metal seals means matched seal and borosilicate or hard glass. It thus is WWII or later and handled a lot of power. The two yellow-green sections in the remote bulb are "Canary" aka uranium glass, aka type 3030 and means the body of the tube is something like 7052 or 7056 aluminosilicate to match to the Kovar sealing metal. The switch to Pyrex for the fill stem is because Aluminosilicate is the devil to work with, as it tends to devitrify when heated hot enough to use as a sealing stem.The coiled coil filament on it's tungsten lead throughs is more then likely used as a pressure gauge. Not a getter.Steve

author: macona
author_rank: Regular Contributor
timestamp: July 12, 2021, 08:47:56 pm
content: Only three terminals so it can't be a thyratron. No signs of mercury, I have some largish mercury rectifiers so I have seen those. The bulb on the side is either a getter or a titanium sublimation pump. Not sure which, it is used to compensate for any outgassing. Either by evaporating a reactive metal on the wall which the gasses left react with or the titanium sublimates when heated and it traps gasses when it condenses on the walls.Cleaned it up and took few more pics, real hard to make stuff out due to the distortions from the glass.UntitledbyJerry Biehler, on FlickrUntitledbyJerry Biehler, on FlickrUntitledbyJerry Biehler, on FlickrUntitledbyJerry Biehler, on Flickr

author: Cyberdragon
author_rank: Super Contributor
timestamp: July 12, 2021, 10:26:24 pm
content: The ring and odd shape suggests some sort of resonator for UHF use, like a klystron or such.There are no identifying marks at all? Not even a makers mark?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 12, 2021, 11:07:19 pm
content: University is interesting; could well be a modified (or brand new, but maybe not given the intricate shapes?) bit of apparatus from the physics department. Don't suppose you have contact with any faculty..?Tim

author: LaserSteve
author_rank: Super Contributor
timestamp: July 13, 2021, 12:02:37 am
content: Are there two long slits in the Anode? Early VHF magnetron comes to mind.It is possible to have a cold cathode large thyratron too. The trick is to fill the hollow cathode base with silica dust and impregnate it with potassium. Then you get a self healing cathode. That method never caught on, expect in some pulsed lasers.But the TSP drives this toward vacuum operation.Ask on radiomuseum.comSteve

author: coppercone2
author_rank: Super Contributor
timestamp: July 13, 2021, 12:28:47 am
content: it defiantly looks like a physics project, universities have glass blowing departments, you would not get that oblong easy to break side piece with a commercial product, or a military product for that matter, they want things to ship nicelyI think its something to let plasma go through the side piece and maybe measure it with something, maybe a current probe?that glass structure is used for convection often, or circulation, its common in a passive circulation oil melting point tester (the circulation is a temperature control, a passive flow network) and a dean stark apparatus. Can it be something for looking at plasma turbulance/dynamics? You can also heat the side tube. not sure what that would do, its very interesting. I think if you put a flame on that side tube and there was gas inside it would start going around in a circle, at least if it was normal gasalways wanted to work on that kind of stuff

author: macona
author_rank: Regular Contributor
timestamp: July 13, 2021, 12:32:37 am
content: I do know some people in the faculty there but this predates everyone there.No marks that I can find anywhere. I looked all over.Dont see any slits in it either.Yeah, I was thinking of asking the guys over at radiomuseum but figured I would give it a try here. If nothing else it is neat to look at. Ill just make a display stand for it.

author: macona
author_rank: Regular Contributor
timestamp: July 13, 2021, 12:35:05 am
content: Im pretty sure the pump sidearm was added, they did have a glassblowing shop but the parts in this are spun and stamped metal which is a but much for a university experiment.

author: coppercone2
author_rank: Super Contributor
timestamp: July 13, 2021, 12:37:17 am
content: keep in mind this looks like 40's or 50's tech, its when people were proud of their work, open ended non commercial research was allowed, etc (think Bell labs)professors used to actually work on research instead of being grant raising enterpenurs trying not to get shut down by commercial business interests. it was also the golden age of being proud of machining. I think the main focus of a professor now is to put subliminal messages in the abstract.I think then they would have said "make that thing good so we can study it deep into the future for the benefit of this university in case the blue print gets lost" and now the department dean would come running along asking if you can perform a simulation to prove an obvious concept instead, and to please not use the printer. I have something related to him pestering the designer for some thing machining cost related in mind but its too complicated and elaborate a joke so I will leave it at that.

author: bdunham7
author_rank: Super Contributor
timestamp: July 13, 2021, 12:55:07 am
content: The two leads going to the coil in the side compartment--where are they connected?Can you show where the tubes from that side compartment are connected? I think the fact that there are two tubes is interesting. If it were just a getter or TSP chamber, I don't think you'd need 2.

author: macona
author_rank: Regular Contributor
timestamp: July 13, 2021, 12:55:22 am
content: Oh, I realize that, my lathe is from that time period. But there are just parts here that scream production pieces to me. Plus this is a very small school, even smaller back then and I have seen a lot of their other glasswork and brought some of it home and non if it is anything like this.Sent a message over to radiomuseum, we will see if they respond. Crossing my fingers.

author: macona
author_rank: Regular Contributor
timestamp: July 13, 2021, 12:59:38 am
content: The TSP has a extra tubulation for evacuation, there is only one connection to the main tube.UntitledbyJerry Biehler, on Flickr

author: LaserSteve
author_rank: Super Contributor
timestamp: July 13, 2021, 01:05:37 am
content: The thing that screams prototype is the ringof screws in the base. That is one massive virtual leak waiting to happen. I work at a university, two of our more senior machinists regularly make stuff like that.Now if a certain admin wanna-be hadn't ordered the destruction of our induction heating and hydrogen furnace systems system I'd be making stuff like that.Steve

author: LaserSteve
author_rank: Super Contributor
timestamp: July 13, 2021, 01:13:33 am
content: If I have to guess a brand, Machlett Labs used to make tubes with similar hallmarks.Steve

author: bsfeechannel
author_rank: Super Contributor
timestamp: July 13, 2021, 01:53:58 am
content: Quote from: macona on July 13, 2021, 12:55:22 amYou can also trythis guy. He claims to have a collection of more than 4000 lamps and tubes. In fact I found a tube that isvery similar in shapeto yours, i.e., it has two opposite electrodes, two glass bulbs, and a middle ring.According to itsdatasheet, it is used to "decouple the receiver from a common transmitting and receiving antenna during a period of transmission".

author: amyk
author_rank: Super Contributor
timestamp: July 13, 2021, 01:59:47 am
content: Could it be X-ray related?

author: LaserSteve
author_rank: Super Contributor
timestamp: July 13, 2021, 02:44:28 am
content: I'm down to a hf/vhf TR/ATR tube or a large Kenotron or Hard Rectifier. May I see a picture or two of the base?

author: Cyberdragon
author_rank: Super Contributor
timestamp: July 13, 2021, 03:00:51 am
content: Quote from: bsfeechannel on July 13, 2021, 01:53:58 amAlready looked there, nothing matches.I agree it is a prototype, but who made it and for what purpose remains to be seen.The constuction is very odd, seeming to be a mishmash of different tubes. I still think it is some form of RF diode or oscillator. It's not a cold cathode thyratron, two terminals have continuity, and the OP says there is no mercury pool. It is possible it's some weird reflex klystron. I don't think it's a kenotron or other very high voltage rectifier, there does not seem to be enough of a gap, a high current rectifier seems more likely if that's the case.The little bulb could be a titanium getter as suggested. They may have intended to melt it off once evacuated but found tiny leaks so left it on to keep it from getting gassy.Try applying a bit of power to the small filament. That might tell us if the tube is gassy or not.

author: LaserSteve
author_rank: Super Contributor
timestamp: July 13, 2021, 03:04:55 am
content: Gently remove the Faraday Mixture, which is Pitch, Beeswax, and Iron Oxide or Copper Oxide and look for a part#.The Faraday Mix is a remarkable vacuum sealant used in the days B.E. [Before Epoxy].Any testing may make it valueless to a collector.

author: coppercone2
author_rank: Super Contributor
timestamp: July 13, 2021, 04:03:20 am
content: Oh, if its not looped around its not a flow thinghowever a flow thing would be interesting in some kind of gas tube

author: macona
author_rank: Regular Contributor
timestamp: July 13, 2021, 04:32:49 am
content: Couple pics of the base. The base has spacers to keep it centered in a chimney or something probably to keep air flowing over the end.UntitledbyJerry Biehler, on FlickrUntitledbyJerry Biehler, on Flickr

author: Cyberdragon
author_rank: Super Contributor
timestamp: July 13, 2021, 05:46:47 am
content: Be mindful that removing the wax may cause a leak if the tube has not already vented.I don't think those bottom spacers are for a chimney, think they are just clips for mounting into the device in general, along with the weird ring around the middle which is also a contact.You say the anode is hollow? Show us down the end of the anode, I have a bit of a theory.

author: macona
author_rank: Regular Contributor
timestamp: July 13, 2021, 06:19:16 am
content: Im not touching it. Its not worth it.Pic down the "anode" it goes almost all the way to the other end. My guess there was a pipe pumping water down the center of it to keep it cool.UntitledbyJerry Biehler, on Flickr

author: Bud
author_rank: Super Contributor
timestamp: July 13, 2021, 07:00:17 am
content: Guess Glasslinger ftom Youtube would know.

author: Cyberdragon
author_rank: Super Contributor
timestamp: July 13, 2021, 07:58:05 am
content: I don't think that's for water cooling, a single pipe does not allow circulation, unless there was a coil/loop of smaller pipe inside a sleeve.My theory is the anode is an emittor/beam former, either for RF or possibly even x-rays. A grounded cooling jacket was likely connected to the ring, the HV negative connected by screw terminal to the sideways stud on the base, and a ring clip connected to the anode for HV +. The bottom of that cavity would be a transparent window for RF/x-ray (yes, there are end firing x-ray tubes, but I have only found diagrams not photos, but basically they seem to use reflected/deflected electrons). Certain x-ray tubes also have odd appendages like that with other electrodes inside (not sure what for).

author: gbaddeley
author_rank: Regular Contributor
timestamp: July 13, 2021, 10:41:38 am
content: I’m leaning towards a high current switch at a few KV, but the trigger mechanism is not obvious.Possibly had a low pressure gas, possibly partially ionised by the side tube / filament arrangement. Similar to a Krytron?A smaller diameter ceramic tube could be placed down the anode tube, to do circulated water cooling, but this device does not seem to be massively high power dissipation (multi KW continuous).

author: LaserSteve
author_rank: Super Contributor
timestamp: July 13, 2021, 11:25:19 am
content: At the time this was in use, a hollow anode would be used for vapor phase,, ie steam cooling or oil immersion cooling. DI water was not so easy to make back then.I've seen the remains of cooling pools at some very old transmitter sites.If the anode has a low Z window at its bottom , ie copper, it might be X-ray. Copper was hated as a low Z material. its better know for use in X-ray crystallography where its modestly high Z is useful due to spectral shaping. There is what looks like a Cadmium Silver or Tig weleded braze line half way down the anode where it reduces in diameter. Crystallography/ x-ray diffraction is a legit College use of X-rays. I just can't see a hollow anode tube being efficient or easy to collimate.Steve

author: Cyberdragon
author_rank: Super Contributor
timestamp: July 13, 2021, 04:12:38 pm
content: A gas fill would be easy to detect, does OP have a plasma globe or any such HV source to see if something ionizes? You wouldn't see much, so darken the room.

author: macona
author_rank: Regular Contributor
timestamp: July 13, 2021, 06:03:08 pm
content: Quote from: gbaddeley on July 13, 2021, 10:41:38 amNah, the side piece is a TSP. They used them on a lot of their other pieces they made like this one:UntitledbyJerry Biehler, on FlickrUntitledbyJerry Biehler, on Flickr

author: dmills
author_rank: Super Contributor
timestamp: July 13, 2021, 07:10:31 pm
content: Flow things are common in gas lasers, where the main beam current acts as an ion pump and they need to provide a gas return path that is long enough to prevent the silly thing ionising that path instead of the main one (It also provides time for triplet quenching).I was thinking xray generator, but one big vacuum diode looks a lot like another.

author: schmitt trigger
author_rank: Super Contributor
timestamp: July 13, 2021, 07:52:47 pm
content: A Crookes X-Ray tube?Found this image in Wikipedia.

author: Gyro
author_rank: Super Contributor
timestamp: July 13, 2021, 08:10:06 pm
content: Quote from: schmitt trigger on July 13, 2021, 07:52:47 pmAh, in the Crookes tube the filament was wrapped around a bit of Asbestos. It's purpose was to liberate a bit of gas so that the vacuum didn't become so hard, due to adsorbtion in the electrodes,for it to conductthat it stopped conducting. Being a cold cathode tube, it needed some gas ions kicking about in order to work at an achievable voltage.P.S. Some early versions actually had a protruding sealed end metal tube (or the glass itself) that you could warm occasionally with a flame instead of a filament. A bit more risky! Too much gas was as bad (worse?) as too little in terms of X-ray production.

author: jmelson
author_rank: Super Contributor
timestamp: July 14, 2021, 02:05:33 am
content: Quote from: bsfeechannel on July 13, 2021, 01:53:58 amThat would be called a "T/R" tube, usually gas-filled, used in old radar sets, to protect the mixer diode in the reciever from the transmit pulse.Jon

author: macona
author_rank: Regular Contributor
timestamp: July 14, 2021, 03:18:31 am
content: I think at this point we can safely say we will never know what the tube is for. Thats fine with me since I had no plans to use it, Im just going to make an acrylic stand for it.

author: bdunham7
author_rank: Super Contributor
timestamp: July 14, 2021, 03:22:44 am
content: If it is modified or one-off, nobody is likely to recognize it for sure. You would have to disassemble it and probably examine that lower structure to have any sort of idea.

author: Cyberdragon
author_rank: Super Contributor
timestamp: July 14, 2021, 05:28:41 am
content: Or you could...give some juice and see what happens. This thing looks beefy enough it would be hard to hurt it.

author: bsfeechannel
author_rank: Super Contributor
timestamp: July 14, 2021, 04:00:29 pm
content: Quote from: macona on July 14, 2021, 03:18:31 amBetter leave that way. We'll all regret if we later discover that this thing is actually a coffee maker.

author: LaserSteve
author_rank: Super Contributor
timestamp: July 14, 2021, 05:32:27 pm
content: Have to x-ray the base. Big X-ray through.Steve

author: eti
author_rank: Super Contributor
timestamp: July 16, 2021, 11:55:54 pm
content: See if you can get hold of "PhotonicInduction" via YouTube/email - he will know if anyone does!