SKC 225-9594 SKC BioSampler - Manual (Page 3)

Operation
Calibration
The BioSampler’s tangential nozzles act as sonic orifi ces. Therefore, if the pump
maintains a pressure drop of 0.5 atm (15 in Hg) or more across the sampler at
normal atmospheric conditions, the fl ow rate will always be the same (about
12.5 L/min) unless one or more of the nozzles become clogged. Figure 2 shows
the recommended calibration set up. Calibration is particularly important when
sampling in areas with non-standard temperature and pressure.
1. Connect a fl owmeter (bubble or dry-gas) to the inlet of the BioSampler.
2. Connect the outlet of the BioSampler (fi lled with collection liquid or coated)
to the inlet of a liquid trap (Cat. No. 225-22) and the outlet of the trap to a
vacuum pump with a vacuum pressure gauge or manometer in line.
3. Adjust the pump until sonic fl ow is achieved (vacuum gauge or manometer
reads between 15 and 30).
4. Read and record fl ow rate, Q
s
L/min.
Figure 2. Calibration of BioSampler
Flow
Meter
Liquid
Trap Vacuum
pump
Mano-
meter
Exhaust
Pressure drop of
0.5 atm (15 in Hg)
2