Michell Instruments MDM300 I.S, User Manual

Page: 44 / 72

MDM300 I.S. User’s Manual
36 97213 Issue 5, October 2017
OPERATION
B Standard Purge (Pressure Measurement)
1. Connect the MDM300 I.S. to the sample gas stream.
2. Adjust the flow rate, using the outlet flow control valve , to between
0.2 & 0.5 Nl/min (0.5 & 1 scfh). The inlet flow control valve should be
fully open.
3. Turn the instrument on - the initialization period begins automatically.
The page will show a countdown of the remaining initialization time. The
status display will read ‘
Initializing internal sensor
’.
4. After Initialization, the instrument will begin Measurement mode. During
the first few minutes of Measurement mode, the displayed moisture value
will drop rapidly below the actual moisture value, before returning to
a stable reading. The instrument display will show an initial measured
value, and the status display will show ‘
Measurement in progress
’.
5. Once ‘
Measurement in progress
’ has disappeared, the instrument is
close to the final dew point. Depending on the conditions, it may continue
to respond for a number of minutes before tracking the measured dew
point.
C Enhanced Purge
1. Connect the MDM300 I.S. to the sample gas stream.
2. Adjust the flow rate, using the inlet flow control valve , to between 0.2
& 0.5 Nl/min (0.5 & 1 scfh). The outlet flow control valve should be fully
open.
3. Turn the instrument on - the initialization period begins automatically.
The page will show a countdown of the remaining initialization time. The
status display will read
‘Initializing internal sensor
’
.
4. Once 2-3 minutes of the initialization period have elapsed, close the outlet
flow control valve and fully open the inlet flow control valve. Then adjust
the flow rate using the outlet flow control valve to between 0.2 & 0.5 Nl/
min (0.5 & 1 scfh).
5. After Initialization, the instrument will begin Measurement mode. During
the first few minutes of Measurement mode, the displayed moisture value
will drop rapidly below the actual moisture value, before returning to a
stable reading. The instrument display will show an initial measured
value, and the status display will show ‘
Measurement in progress’
.
6. Once ‘
Measurement in progress’
has disappeared, the instrument is
close to the final dew point. Depending on the conditions, it may continue
to respond for a number of minutes before tracking the measured dew
point.