50
‘Target Gas Percentage’ indicates the stream gas percentage that the operator wants during
the experiment.
‘Gas flow rate values to set’, in Normal liter per minute [Nl/min], are the values of gas flow
rate to set on the graduated scale (see Figure 41).
‘Total’ indicates the measured total gas stream flow rate.
Example
►
The target Air percentage is 95.00%, the target CO
2
percentage is 5.00%. Table 4,
shows three possibilities that reach the required gas percentage. Notice that the values are a
compromise between CO
2
consumption, condensation (normally it decreases if Total gas
stream flow rate increases), and medium evaporation (normally it decreases if Total gas
stream flow rate decreases). In the example below (Figure 44) the gas flows on the second
line in Table 4 are shown. Set the flow meters keeping in mind that the correct position of the
indicator (floating ball) is about in its middle. The gas stream mix contains, now, 95.00% of
Air and 5.00% of CO
2
.
◄
Figure 41. Flow meters graduated scales, example for two gas lines.
If you use a pre-mixed 5% CO
2
gas source connect it to the Air port labeled “Air In” on rear
panel of the Control Unit and set the flow rate at the suggested value of 0.3 L/min (See Figure
