Operating TOPwave
52
After connecting the condensation unit to the vent tube, the unit can also be employed
to evaporate acids. For this process, the pressure vessels are operated with a special
screw-on cap, without TFM-PTFE lid. The vent tube used for evaporating is equipped
with a temperature sensor which must be connected to the socket provided for this pur-
pose on the rear of the unit.
The TOPwave microwave evaporating unit is used to concentrate acids or sample diges-
tion solutions obtained after digestion procedures employing HNO
3
, HCl, HF and water
by means of distillation at ambient pressure. The escaping acid vapors are condensed
and neutralized in a 3-stage, water-cooled gas scrubber system. The unit is not suited
for concentrating acids or liquids with a boiling point above 200°C (392°F) such as sul-
furic and phosphoric acid.
For safety reasons (explosion hazards) the use of per-chloric acid and organic sol-
vents is prohibited.
6.7.1 Installation and Commissioning
Aside from the requirements cited in the “Ambient Conditions” p. 13 section, the opera-
tion of the gas scrubber also requires a coolant water connection (approx. 0.5 li-
ters/min. with an inlet temperature not exceeding 20 °C, 68 °F). In addition, there is also
the need for an increased space of 53 x 27 cm (20.9 x 10.6 inch).
Due to the hot acid vapors generated, the microwave oven and the gas scrubber system
must be set up under a vent hood or other exhaust system. The exhaust chamber must
always remain securely closed during the entire evaporating process.
As illustrated in the figures below, add marble granulate to 2 of the gas scrubber
bottles (fill each approx. half-way). Fill the third bottle with NaOH solution (at least
0.5 mol/l NaOH).
Connect the bottles as illustrated in the figures and place the bottles in the cooler.
2 Marble granulate
Add marble granulate to 3 of the gas scrubber bottles (fill each approx. half-way).
Fill the fourth bottle with NaOH solution (at least 0.5 mol/l NaOH).
Connect the bottles as illustrated in the figures and place the bottles in the cooler.
Ambient conditions
with 3 bottles
Gas scrubber
with 4 bottles
(from 2015)
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