Final Flow (ml/min) – This is the ending dry purge flow rate programmed in
ml/min. The final flow can be programmed from 0 to 500ml/min in 1ml/min
increments.
Once the desired options are selected, <click> the Exit button to return to the
Method Screen.
Figure 3j: Programmable Dry Purge Parameters
Final Hold Time (min) – The final hold time will be the difference of the final
dry purge time from the sum of the initial time and the time needed to achieve the
final flow rate.
For Example: Total Dry Purge Time = 5 minutes
Initial Flow = 40ml/min
Initial Hold Time = 0.5 minutes
Ramp Rate = 40ml/min per minute
Final Flow = 200ml/min
The Final Hold time at 200ml/min would be 0.5 minutes.
Explanation: It takes 4 minutes to ramp from 40ml/min to 200ml/min at a
rate of 40ml/min per minute. The final hold time is calculated to be 0.5
minutes.
5 minutes – (0.5 minutes + 4 minutes) = 0.5 minutes
Dry Purge Time (min) – This is the total length of time for dry purge. The dry purge
time can be programmed from 0.0 to 999.9 minutes.
Desorb Pressure Control (psi/kPa) – This pressure setting enables the Encon EV to
equilibrate the concentrator system pressure to that of the GC head pressure prior to
desorb preheat.
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