[sdiy] Mercury Vapor Rectifiers

[KA4HJH]

>Now for the question: I've read in a couple of places that mercury
>vapor rectifiers emit mercury vapor into the air outside of the tubes,
>but since these are sealed vacuum tubes, I don't see how this is
>possible.  Is there something that I'm overlooking, or are, as I
>strongly suspect, any writings mentioning that possibility written by
>someone who's extremely mistaken about the dangers of these tubes?

I have it on good authority that the answer is yes. Remember that the
pressure outside the envelope is much higher than the pressure inside. If
the seal is lost the envelope will be contaminated with air and the device
will fail. There's no way any mercury can escape unless this happens in
which case the device tells you by ceasing to function.


>(ok, if they're dropped, or something falls on them, I realize that
>there will be a little problem of some mercury on the loose and will
>have an excuse, a safety reason, for not bothering with using a vacuum
>cleaner to keep my work area clean).

Exactly. Now the device is a toxic hazard. Just like a broken fluorescent
tube or mercury-argon "neon" sign (which may have toxic phosphors in them
as well).


At 6:20 PM +1000 3/27/06, Paul Perry wrote:
>Don't look at that cool purple/blue glow too long.
>I've seen a guy with a bad case of UVitis
>(eye damage) from the UV radiation from the
>mercury rectifier in a WW2 communications receiver rack
>(an AR88 from memory).

There's that as well. It pays to wear glasses that are opaque to UV. We
were lectured a lot about mercury and UV in neon school (HV, too).


OK, now that we've got all the thrillseekers wound up about tubes/valves...

-- 

Terry Bowman, KA4HJH
"The Mac Doctor"