The setup I have used for 4 years is simple and and it has maintained
excellent vacuum:

A Kel-F tube is machined to fit a NPT male connector welded onto the SS
line. The assembly is solid and sustain very well the freezing and thaw of
distillation and holds pure BrF5  for weeks if necessary. By welding the
NPT adaptor to the line, there is only one fitting that may leak.

Dr. Georges Beaudoin
Professeur
Département de géologie et de génie géologique
Université Laval
Québec, Québec
Canada
G1K 7P4
tel.: 1-418-656-3141
fax.: 1-418-656-7339