BUCHI Scrubber K-415 - Manual (Page 39)

5 Putting into operation
39 K-415 Operation Manual, Version B
5 .11 Preparation of the adsorption vessel
NOTE
When you carry out Kjeldahl digestions, the suction capacity might become too high. Therefore we
recommend to fill activated charcoal into the adsorption vessel and to add glass wool at both ends.
The glass wool prevents charcoal from being drawn into the vacuum pump. The activated charcoal
should be grainy with a particle size of 2 to 6 mm.
! CAUTION
Risk of instrument damage and risk of serious chemical burns by corrosives.
• Never use charcoal in the form of powder or with a particle size below 2 mm - otherwise the
adsorption vessel will get clogged and as a result the pump will get damaged.
Fig. 5.16: Adsorption vessel with activated charcoal and glass wool
5 .12 Filling the reaction stage
For digestions with aqua regia it becomes necessary to fill the reaction stage with around 350 mL of a
saturated FeSO
4
solution (~27 g/100 mL) to dispose of the nitrous gases.