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Technical Data
8.3 Purging
LDS 6
88
Operating Instructions, 01/2009, A5E00295894-05
8.3
Purging
Conditions of purging media
As medium nitrogen is permissible for purging the sensor side. Nitrogen, steam, air and
gases which are not subject to the pressure equipment directive Cat. 2 are permissible as
purging gases for the process side.
Table 8- 12 Purging with air and nitrogen
Purging with instrument air, N2
Pressure at purging inlet
200 ... 800 kPa
Maximum overpressure in the sensor
< 500 hPa
Quality
- Instrument air
- Nitrogen
free of oil and water
Purity better than 99.7 %. For oxygen
measurements, an O
2
content < 0.01 % is
recommended in the purging gas (optical path
length ≥ 1 m, min. 5 % oxygen in the process
gas)
Maximum flow rate
500 l/min
Dew point
Benchmark: ≤10 °C,
condensation on the optics must be avoided
Table 8- 13 Blower purging
Blower purging
Maximum counter pressure
4 kPa
Maximum flow rate
350 l/min
Power consumption
370 W
Degree of protection (fan)
IP54
Table 8- 14 Steam purging
Steam purging
Steam conditioning
Overheated
Maximum temperature
240 °C
Minimum pressure
> 400 kPa
Maximum pressure
1 600 kPa,
refers to a volume flow of approx. 1 100 l/min