chemrox - 13-2-2009 at 12:41
This is a new, more precise system for me. I'm having trouble setting it up. Anyone who has one or has used one please send me PM or answer here.
Meanwhile I'm in touch with Ace but they don't seem to have anyone with actual experience using it. Who knows (?) who wrote the manual but it's not
all that clear and if you don't set the stopcocks right during pump down Hg gets into the lines.
Thanks,
CRX
bbb - 3-3-2009 at 23:44
You'll find an article describing the use here: http://www.belljar.net/v10n34.pdf
Basically, you need to add 20-30 ml of mercury for the float to float on, you have the stopcock set so the whole system is open to vacuum, then when
you've reached your target pressure you close the valve so when the pressure drops in the system, the reference pressure pushes the float up to close
the system to the vacuum. should the pressure rise again, from leaks or whatever, the float is pushed back down opening it to the pump.
The older version just has a medium glass frit and the mercury is moved around with the pressure changes to seal it. We have one that probably needs
five pounds of mercury in it.