While this is an extreme case, and easily preventable, I'd be more concerned about starting a fire were this to actually happen.
The amount of mercury in a small tube rectifier like an 866 or 816 is relatively small. Since mercury loves to amalgamate with other metals, proper clean up would involve pouring powdered tin, or zinc over the spill. (copper, lead or silver would also work) The mercury will immediately become a solid and is easier to pick up as it is locked up in an amalgam and poses no threat.
We all know that mercury evaporates at room temperature. If no clean up were attempted, this small amount would dissipate in a matter of days or weeks. Not years. It would be necessary to ventilate the room for at least that long. And I've been told that mercury vapor can be detected with an ultra-violet light to cast it's shadow. I also believe there are inexpensive "sniffer" type testing devices available.
Never attempt to vacuum up raw mercury as this would only spread it around more making clean up much worse. And for a tiny spill as mentioned here, never get any government agency involved. They will exaggerate the situation way beyond reality making it your worst nightmare. Or so I've been told.
Victor
Cool,
I'll keep agencies and authorities out of my tube affairs .I have a few types of MV rectifiers waiting to be used (Big WE M, 872, 866 , 83 , 82 ). One of old WE (forgot the type and don't want to dive into shelfs to check ) is a little foggy/gassy inside .Do you think its a problem ? Regards, L
I'll keep agencies and authorities out of my tube affairs .I have a few types of MV rectifiers waiting to be used (Big WE M, 872, 866 , 83 , 82 ). One of old WE (forgot the type and don't want to dive into shelfs to check ) is a little foggy/gassy inside .Do you think its a problem ? Regards, L
Jeb-D. said:
Hi Jeb,
If you are talking about mercury vapor rectifiers the mercury vapor lowers the voltage drop across the tube to typically 15V or less and at quite high currents in some cases.
They also exhibit a relatively constant drop over large swings in load current resulting in much better voltage regulation with variable loads. (Like big class B amplifiers.)
Some damper tubes are nearly as good at currents below roughly 1A, 5AR4 will manage 25 - 30V at 250mA..
Mercury rectifiers are right perty to look as long as you don't get one made with quartz glass which does not block UV. (Rare)
So, Kevin and HollowState. Do you know if a tube has to be designed from the ground up for gas or can conventional tubes be charged with it? Also, does it only apply to diodes?
In otherwords can I take some of my favorite triodes and have them charged with Xenon (obviously MV is wouldn't be do-able). And have the behave like on Steroids?
Like say, a 6c33c that can pass 1A+ continuous with a lower Rp. If you know what I'm getting at.
If it may be a worthwhile experiment, I may have the resources to try it, and the amp to try it in
In otherwords can I take some of my favorite triodes and have them charged with Xenon (obviously MV is wouldn't be do-able). And have the behave like on Steroids?
Like say, a 6c33c that can pass 1A+ continuous with a lower Rp. If you know what I'm getting at.
If it may be a worthwhile experiment, I may have the resources to try it, and the amp to try it in
Difficult to say without knowing more. Some rectifiers that contain mercury, and are old, may have some amount of air due to a compromised vacuum. In others, the mercury may not condense totally when cool. One way to help judge is to light the filament and watch what happens inside. Normally the mercury will vaporize and slowly coat the inside making it more opaque. If the filament seems to light very dim it may have air inside. If it smokes it definitely has air.
I've seen tubes, mostly transmitting types, that were air bottles and the filament had smoked giving the inside an ugly yellowish color.
Something to be very cautious of when using NOS American 866's (RCA, Sylvania, etc) from the 60's and 70's is they can short out when first powered up. These tubes had a coating on the plate and body surrounding the cathode that would peel off and flake when first heated up. This applies mainly when they haven't been used in a long time and mostly to the fatter bulb style, as compaired to the slim types of later production. These flakes would find their way between the plate and cathode structure and the tube would short, often with dramatic results.
If anyone has these old rectifiers, look for an orange peel texture to the coating on the elements. This is a dead giveaway. But I've seen perfectly smooth coatings wrinkle and peel too. With these old dogs, it's always best to heat them up and test with low voltage before using them. This also applies to old 872's as well. Voice of experience here.
Victor
Have you ever known anyone who used steroids? Often a highly unstable bipolar person. The same would happen to your tubes.
Seriously the purpose of "gas" inside a tube is to allow for controlled ionization of the gas. When the gas ionizes the internal impedance of the tube drops quickly. In a rectifier the mixture and pressure of the gas is adjusted such that the gas ionizes in the forward direction only. As previously mentioned the forward voltage drop is relatively constant over a wide range of current. The same principle is used to make the VR tubes.
When gas is introduced to a multi element tube it casuse a controlled avalanche effect. The conduction through the tube is very low until critical bias is achieved, then the tube ionizes resulting in a very low plate to cathode voltage drop. Once ionization occurs it will continue until plate voltage is removed. The grids have no effect. As stated before this is a thyratron. The action is similar to an SCR.
None of these tubes have any usable linear region so they can't be used for an amplifier. They are "on" or "off", bipolar.
dumb answer... that's ridiculous
>>Carlp Wrote:
"Yeah, perhaps you're likely to DIE more quickly IF your spouse smokes (mine doesn't), but mercury is a SERIOUS neurotoxin that's likely the cause of an apparent epidemic of autism in the US"
Any reference for this statement?? just the kind of idle speculation that turns into urban legend and then becomes grounds for some sort of mindless legislation... like banning lead from solder, for instance.
Epidemic of autism??? Gimme a break... we deal with these kinds of fear mongering on a daily basis in our patient population... there is no epidemic of autism in the US...
Do you drive a car? More likely to die from that than from mercury poisoning...
>>Carlp Wrote:
"Yeah, perhaps you're likely to DIE more quickly IF your spouse smokes (mine doesn't), but mercury is a SERIOUS neurotoxin that's likely the cause of an apparent epidemic of autism in the US"
Any reference for this statement?? just the kind of idle speculation that turns into urban legend and then becomes grounds for some sort of mindless legislation... like banning lead from solder, for instance.
Epidemic of autism??? Gimme a break... we deal with these kinds of fear mongering on a daily basis in our patient population... there is no epidemic of autism in the US...
Do you drive a car? More likely to die from that than from mercury poisoning...
Thanks for the replies and info on mercury. Aupulator, I tried to send a response off thread but couldn't, so here goes a few final words, then I'll leave the thread to it's real purpose.
As for the autism link, I never said it WAS the cause, just the likely culprit based on a LOT of recent research. There is an "epidemic" of autism as rates have increased dramatically of late. Of course this could be due to increased scrutiny, but most scientists and epidemiologists believe it's a real trend. I'll try to dig up some quick references.
And yes I do drive a car - more than I'd like to - and I never said mercury was more likely to kill anyone. That doesn't mean it isn't a real problem. Idle speculation? I think not. Perhaps idle relative to mercury vapor tubes - I know little about them.
Carl
As for the autism link, I never said it WAS the cause, just the likely culprit based on a LOT of recent research. There is an "epidemic" of autism as rates have increased dramatically of late. Of course this could be due to increased scrutiny, but most scientists and epidemiologists believe it's a real trend. I'll try to dig up some quick references.
And yes I do drive a car - more than I'd like to - and I never said mercury was more likely to kill anyone. That doesn't mean it isn't a real problem. Idle speculation? I think not. Perhaps idle relative to mercury vapor tubes - I know little about them.
Carl
LOL
Heek! I broke a 866A once. And it was removed off the socket still hot so mercury was not liquid. I opened the window plugging my fingers in the nose and allowed a couple of hours of ventilation (in the room, not in the nose). It didn't scare me enough and it didn't prevent me from using more and more MV rectifiers.
But probably it was enough, I went crazy from that very day. Who else uses two 40kg amps to listen to just .1W?
Gianluca (the HG sniffer)
Heek! I broke a 866A once. And it was removed off the socket still hot so mercury was not liquid. I opened the window plugging my fingers in the nose and allowed a couple of hours of ventilation (in the room, not in the nose). It didn't scare me enough and it didn't prevent me from using more and more MV rectifiers.
But probably it was enough, I went crazy from that very day. Who else uses two 40kg amps to listen to just .1W?
Gianluca (the HG sniffer)
No chance here then
I remember as a small boy, that one little treat was to visit a friend nearby. His father had lots of exciting things in his garage, including a bottle of mercury - "quicksilver" he called it. Hours of fun for us small boys, rolling it around with our fingers.
SInce then I have had my teeth stuffed with amalgam, inhaled petrol (in the course of messing about with cars) and paint thinner, model aircraft glue, been covered in brake fluid, old engine oil, antifreeze, driven for forty years, smoked for forty-five years; girlfriend smokes more than I do and I consume more than the recommended amount of alcohol daily. I built amplifiers running at over 1kV, testing power supplies on the floor. And there was the night I built a bench lash-up to test some 4212Es at 1.5kV -after we had all been rather too long in the pub.
To paraphrase the old song: "Bin doin' it all my life and I ain't dead yet!"
No risk: no life, although I would concede that luck probably has something to do with it.
7N7
I remember as a small boy, that one little treat was to visit a friend nearby. His father had lots of exciting things in his garage, including a bottle of mercury - "quicksilver" he called it. Hours of fun for us small boys, rolling it around with our fingers.
SInce then I have had my teeth stuffed with amalgam, inhaled petrol (in the course of messing about with cars) and paint thinner, model aircraft glue, been covered in brake fluid, old engine oil, antifreeze, driven for forty years, smoked for forty-five years; girlfriend smokes more than I do and I consume more than the recommended amount of alcohol daily. I built amplifiers running at over 1kV, testing power supplies on the floor. And there was the night I built a bench lash-up to test some 4212Es at 1.5kV -after we had all been rather too long in the pub.
To paraphrase the old song: "Bin doin' it all my life and I ain't dead yet!"
No risk: no life, although I would concede that luck probably has something to do with it.
7N7
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