DURAG D-R 290, Operating Manual

Page: 155 / 202

8 | Maintenance
D-R 290 155
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the general ambient circumstances (e.g. climatic conditions at the measuring point)
It makes sense to start with a short maintenance interval (typically 4 weeks). The
maintenance interval can then be increased step by step up to a maximum of 6
months, in accordance with the prevailing conditions.
Maintenance should be performed during an inspection of the system being moni­
tored, i.e. this means the system is not in operation.
Irrespective of this however, a check should be performed every four weeks. The
check is to look for external changes such as deposits, faulty seals, colour changes on
the casing, etc. It is also a check that all screw connections, closures and devices are
tightly secured.
If the measuring system is not maintained or insufficiently maintained, increasing con­
tamination of the lens and filter, if necessary in accordance with the respective instruc­
tions for the system, may lead to the failure of the measuring head and possible dam­
age to it.
Table of maintenance work (suggestion)
K* Activity Who When
a Visual inspection and cleaning of external parts of the device Operating personnel** every four weeks
a Checking the closures and screw connections Operating personnel** every four weeks
a Check the purge air unit and the hose connections for leaks
and secure fitting
Operating personnel** every four weeks
b Remove deposits on and within the welded-in pipe Operating personnel** every four weeks
b Purge air blower:
Checking the filter
Changing the filter
(see also Checking / changing the filter)
Specialised staff**
every four weeks
typically every
3 months
b Cleaning the purge air hoses Specialised staff** Typically every
3 months
b Measuring head:
Checking the contamination value (see --- FEHLENDER LINK
---),if necessary cleaning the device glasses
Specialised staff** every four weeks
b Check the performance LED alignment Specialised staff** Typically every
3 months
a Check the measured values for contamination, zero point and
reference point
Operating personnel** every four weeks
b Linearity check (see Checking the linearity) Specialised staff** 1/year
* K ≘ Category - ** Definition see section 2.4 Personnel [
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22]
Table 8.1: Suggestion for checking and maintenance work
Category for maintenance work
Work of category "a" can be performed whilst the plant is in operation (the work in­
structions are created by the operating company). Work of category "b" requires the
purge air to be switched off.
When performing any maintenance work of category "b", ensure that:
The purge air is necessary for protection of the component units. The purge air shields
components from hot and/or aggressive gases. Loss of the purge air supply even for a
(very) short time can lead to malfunctions, damage or total write-off of the measuring
head.