DURAG D-R 290, Operating Manual

Page: 156 / 202

8 | Maintenance
156 D-R 290
In the event of over-pressure in the measurement duct, the gas can also pass through
the purge air hose to the fan and air filter, and damage those system parts also.
The measuring head and reflector will be damaged if the purge air supply fails
If the purge air supply is not running, the measuring head and reflector within the duct
will be irreversibly damaged within a short time due to excessive heat and dust.
▶
It is absolutely essential that the measuring head and reflector are removed from
the measurement duct before the purge air is switched off!
▶
Under no circumstances allow the measuring head and reflector to remain in the
measurement duct if the purge air supply is not running.
▶
Ensure a reliable supply of purge air, even when the system is stopped.
Also see about this
2
Contamination check [
}
161]
Visual inspection and cleaning of external parts of the device
In accordance with the maintenance intervals specified by the operator the dust con­
centration and opacity monitoring system is initially subject to a regular visual check.
The check is to look for external changes such as corrosion, faulty seals, colour
changes on the housing, etc. There is also a check that all screw connections, clo­
sures and devices are tightly secured.
Use oil-free compressed air or a soft lint-free cloth, moistened with water and
Isopro­
panol [
}
195] if necessary, to remove any deposits.
Check the purge air unit and the hose connections for leaks and
secure fitting.
Check the purge air unit, including the purge air hoses, for damage.
Check the hose connections for leak-tightness and secure fitting.
Checking and changing the filter
The filter cartridge can be cleaned several times before it has to be replaced. The
maintenance intervals for the filters depend on the quality of the intake air.
1. System is out of operation, otherwise close the fail-safe shutter.
2. Open the filter housing lock. Check the purge air filter at the purge air blower
3. If there is loose dirt in the housing: Remove the filter cartridge.
Clean the filter housing (and the filter if required).
4. Insert a filter cartridge. When closing the filter housing make sure that the interlock
engages.
5. Switch off the power to the purge air unit (blower).
6. Reconnect the power supply to the purge air unit.
7. If necessary check that the fail-safe shutter opens again.
8.2.1
8.2.2
8.2.3
Fig. 8.1: Purge air filter