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8020216/19YN/V3-0/2020-12| SICK
O P E R A T I N G I N S T R U C T I O N S | DUSTHUNTER SP100 Ex-3K
Subject to change without notice
PROJECT PLANNING
4
4.2.3
Purge gas supply
The sender/receiver unit must be permanently supplied with purge gas during operation in
order to keep the optical surfaces clean and to cool the measuring probe (especially at high
gas temperatures). The customer must provide the purge gas as compressed air (e.g. air,
nitrogen) with a pressure of 2…6 bar
abs
. The purge gas line is connected to the non-return
valve (internal thread G¼"). The purge gas line must be made of antistatic material to avoid
electrical discharge.
Purge gas requirement
For DUSTHUNTER SP100 Ex-3K Standard version:
3…5 m
³
/h
For DUSTHUNTER SP100 Ex-3K High temperature version:
18…20 m
³
/h
In order to adjust the purge gas volume, it is recommended to install a flow meter
upstream of the non-return valve
. A filter regulator
(pressure regulator with filter
element and possibly pressure gauge) must be provided upstream of this to be able to
adjust the purge air volumes.
Fig. 21: Purge gas supply DUSTHUNTER SP100 Ex-3K
The following Table shows the compressed air requirement at different pressures of the
supplied compressed air. The values are calculated for a compressed air temperature of
20°C and a duct overpressure of 30 mbar.
Table 12: Compressed air requirement
Purge gas quality
In addition to cooling the measuring probe, the supplied purging gas is mainly used to keep
the optical surfaces clean. The purge gas should be dry and free of dust and oil. The cleaner
the purge gas, the less the optical surfaces become dirty. The maintenance cycle can thus
be considerably extended.
Non-return valve
Flow meter
Filter regulator
Compressed air
requirement in m³/h for
purge air volume
Pressure of the supplied compressed air in bar
abs
2.0
3.0
4.0
5.0
6.0
3 m³/h purge air
1.6
1.1
0.8
0.6
0.5
5 m³/h purge air
2.7
1.8
1.3
1.1
0.9
18 m³/h purge air
9.6
6.4
4.8
3.8
3.2
20 m³/h purge air
10.7
7.1
5.3
4.3
3.6
