Labconco Rapid Distillation Apparatus 65000 - Manual (Page 12)

NORMAL OPERATION
8
chamber until all of the solution is added. Leave column of caustic in the funnel stem to
act as a liquid seal.
NOTE: If reaction is uncontrollable, REDUCE all future acid digest sample volumes and
re-calculate required alkali solution strengths so that inner chamber contents will have a
normality of 4 to 8. A small amount of caustic should be left in the addition funnel to act
as a liquid seal during each distillation. If foaming is a problem during distillation, add 1
or 2 drops of anti-foam reagent.
(12) Allow distillation to proceed long enough to complete the quantitative recovery of
ammonia free from the sample. Average time of distilling is 3 to 5 minutes.
(13) Lower receiver flask shelf and allow distillation to continue approximately one minute.
(14) Place receiver flask aside. It is now ready for titration.
(15) Place an extra flask on receiver shelf, open aspirator tube stopcock, to “drain out” the
mixing chamber. Open sample addition stopcock, letting liquid seal pass into the mixing
chamber. Close addition stopcock. Drain out by means of the aspirating action. Follow
with several good washes of ammonia-free distilled water, adding each wash through the
addition funnel, closing the addition stopcock and aspirating the washing solution to the
drain.
NOTE: Close aspirator stopcock before addition of each wash.
(16) The unit is ready to handle the next sample
NOTE: If long delays are encountered between sample runs, aspirate mixing chamber just
prior to sample digest introduction.
Shutdown
(1)
Turn off heater with main switch.
(2)
Remove receiver flask.
(3)
Wash out mixing chamber thoroughly, leaving it about ½ full (10-12 ml – refer to Step 15
of Start-up and Operation).
(4)
Turn off cooling water source to condenser and flow control valve.