Hello, nice! Are You sure the valve above the pump is vacuum tight? I guess it is ball valve, I would look for the leaks here. Keep the rubber joints as short as possible (try the glass tube almost touching the metal inside the hose), that is because the rubber permits some amounts of gases inside through its wall, search for "vacuum permeability). But rubber is far better than silicone. If You have a high vacuum grease, coat slightly the glass tube and metal tube before joining. Did You try blanking the flanges for neon and tube (only the pirani will be present), just to make sure the system is leak tight?
Dalibor Farný http://dalibor.farny.cz sent from Samsung Galaxy Pad Dne 28.10.2012 17:36 "jb-electronics" <webmas...@jb-electronics.de> napsal(a): > Hi folks, > > I received my needle valve yesterday and improved my vacuum system. It > works nicely: I can evacuate the system down to about 0.01 mbar and then > use the needle valve to let in well-defined amounts of Neon. I can easily > adjust the pressure inside the system in steps of 0.1mbar which is more > than sufficient. See my current setup here: > > http://www.jb-electronics.de/**tmp/vacuum_system.jpg<http://www.jb-electronics.de/tmp/vacuum_system.jpg> > > But there are some minor leaks, mainly caused by the rubber hose > connectors that I use: I still have to figure out a proper way to connect > my 8.8mm tubing to the KF16 flange system; right now I am using an ordinary > rubber hose as seen in the picture. Does anyone know how to build or get a > proper pump union? Just like here, but with a flange adapter: > > http://www.teralab.co.uk/**Glass_Blowing/Pump_Unions/** > Pump_Unions_Page1.htm<http://www.teralab.co.uk/Glass_Blowing/Pump_Unions/Pump_Unions_Page1.htm> > > I do not have a lathe at my disposal. Also, the connection between the > pressure reducer and the needle valve is not optimal. Any suggestions? > > Thanks > Jens > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To post to this group, send an email to neonixie-l@googlegroups.com. > To unsubscribe from this group, send email to neonixie-l+unsubscribe@** > googlegroups.com <neonixie-l%2bunsubscr...@googlegroups.com>. > For more options, visit > https://groups.google.com/**groups/opt_out<https://groups.google.com/groups/opt_out> > . > > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
