Subject: How do the get the sodium in the valves?

From: [email-masked] (Joe)
Date: 3 Jul 1996 15:11:32 GMT

How do they get the sodium in the valves in the first place?

Joe

P.S. The thread on sodium in the valves was excellent. Kudos to those who
contributed.

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From: [email-masked] (philip evans)
Date: Wed, 3 Jul 1996 16:41:22 GMT

>How do they get the sodium in the valves in the first place?

Sub-contract to Cadbury.

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From: [email-masked] (Jonathan M. Elson)
Date: 6 Jul 1996 05:58:33 GMT

Joe ([email-masked]) wrote:
: How do they get the sodium in the valves in the first place?

: Joe

I assume the whole operation is done in an inert atmosphere in some kind
of enclosed processing system.  I think the valves are made in one piece,
with a hollow stem, open at the rocker-arm end.  The sodium is either
melted and dripped in, or comes in the form of a thick wire that is cut to
the desired length and dropped in.  Then the end is welded closed, or an
end piece is welded on.  The end of the valve is then ground so that it
will slip through the guide.  I suspect that the next step is a dip into
a bubble chamber (in this case filled with fluorinert or light oil).  The
pressure in the bubble chamber is lowered, and the valves are visually
observed for bubbles.  Any that produce bubbles are thrown out.  They want
to be sure there are no leaks in these things.

If done carefully, this could actually be done in dry air, but the chance
of a fire is too great, I think.  So the inert atmosphere is most likely.
Nitrogen, Argon or something like that would be likely.  If they use
Argon, then they wouldn't even need to shield a mig welding electrode.
The whole chamber is shield gas!