mru SWG100 BIOEX, User Manual, Page: 27 / 150

MRU GmbH SWG 100 BIO Ex User Manual
Page
27
of
150
Description of the CH4 cabinet monitoring
The main parts of the system are following:
•
The CH4/CO2 NDIR- bench.
•
A solenoid valve, which feeds the atmosphere inside the case to the CH4/CO2
NDIR bench.
The figure below shows the position of the two components.
•
The CH4 cabinet measurement is inforced after each air purging phase / zero point.
This phase takes 2 minutes and is called 'CH4 case measurement'. During this phase
the menu indication bar will indicate '
CH4 case meas.'
and a count-down starts.
•
During this phase, all solenoid valves are closed and the solenoid valve, which feeds
the gas from inside the cabinet, will open. The first 90 seconds of the CH4
monitoring is used to feed the inside cabinet atmosphere to the NDIR bench.
Only
in the last 30 seconds the CH4/CO2 NDIR- bench detects the CH4 concentration .
During this time the measured CH4 values will be shown also as life values.
•
The CH4 concentration is displayed as CH4 % concentration as well as CH4
concentration in % LEL in the measurement menu (see screenshots below).
•
If the CH4 concentration rises over an user defined value, an alarm will be triggered
for 2 minutes. After the 2 minutes the analyser will power down to prevent an
explosion.
•
The CH4 alarm threshold can be set in the general menu (find on the path:
E
XTRAS
/
GENERAL MENU
).
• If the user must perform maintenance works on the analyser and the alarm appears,
it is possible to delay the power down for 1 hour to max 2 hours. The alarm menu
can be closed with the key
F1
or
ESC
. The alarm is still active, the user will see a
flashing red 'OFF' on the menu indication bar.
Solenoid valve for CH4 monitoring
CH4 / CO2 NDIR-bench
Menu screen in the „CH4
case meas.” mode