-EN Rev. E Operating instruction SCK Gas Sampling System 33
Compressed-air tank and pneumatic system
The compressed-air system serves to retract the probe out of the rotary kiln
in the event of malfunctions, e.g. power supply failure. The compressed air is
also used to clean the probe for certain types of probe.
The compressed air must meet the following minimum requirements:
Dew point +3 °C
Pressure 6 bar (6000 hPa) positive pressure
Consumption approx. 3 m
3
/h
One probe travel (2 x 20 s) requires approx. 1 m
3
.
Other requirements are:
The compressed air must be free of dirt and oil/water droplets.
At ambient temperatures below 0 °C make sure that the compressed-air
supply cannot freeze.
The sampling system can be fitted with a 250-l compressed-air tank. The
compressed-air tank serves to back up probe movement if the on-site com-
pressed-air supply fails.
This tank is not required if the on-site compressed-air supply is of stable
performance.
Meaning
compressed-air tank