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Copy of: Re: small tube filling pressures
---------- Forwarded Message ----------
From: arturo de carlo, 101550,350
TO: INTERNET:EclectiKat@aol.com, INTERNET:EclectiKat@aol.com
DATE: 4/25/96 9:57 PM
RE: Copy of: Re: small tube filling pressures
To Jeff and Marcus,
I only ment the outgassing of the the tubing (extremely important) at that
specific 180 C temperature.
The second Wasserslach (forgive me Jeff it's German word and I will ask our
German friend what the correct word is, Marcus do you know the translation for
Wasserschlag into proper English) is be at a much to higher tempurature you
never can reach during bomabrding.
The only temperature that hydrogen is coming free out of the bowl of the glass
is in the range between 175 and 185 degrees C.
At that specific temp (180 C) the structure (pores) of the glass are wide open,
so that the pump can suck out the hydrogen that is coming free from the
glasstube at this temperature.So having a hysteresis of halve a minute for the
tube at this temperature makes sure that the hydrogen coming out of the glass is
sucked off. Not following this procedure the hydrogen will come free during
lifetime. The ouside of the tube is at atmospherical pressure and therefore is
pushing small particles through the wall of the tube, like hydrogen and helium.
The inside of the tube is at a very low pressure, a few milibars. (I think it is
millibars) So the hydrogen will be pushed through the glaswall into the tube,
and that 's not what we want because the pressure in the tube is rising while
the light output of the tube is dimming. We see this phenomenom frequently with
the ruby red tubes and it lies in the fact as I described above. Thinking about
this, maybe this can be a reason to install a transformer one step higher then
calculated as doing this trick one is compenasting the higher Ri of the tube
after time as the transfomer can increase it's secundairy voltage without
damaging itself, as it was originally designed to operate for that Ri.
Best from dirk.
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