ABB ProKiln GAC400 Operating Instruction page 119

ProKiln GAC400 PROBE GAS SAMPLING SYSTEM | OI/GAC400-EN REV. A
Probe retractor: Checking and adjusting the position of
the probe
Safety measures
WARNING
Dangers when performing maintenance work.
Always take the following safety measures when performing
this work:
• Wear a face mask against heat, heat-proof gloves, and
protective welder's clothing.
• Operation/Service Mode -50S15 switch must be in the
Service Mode (with a padlock).
• Additionally press the EMERGENCY STOP switch.
• Do not enter the danger area around the retractor until it
is at standstill and the warning lamps and buzzer are off
and the shutter is closed.
• Do not perform the work until the probe gas sampling
system has cooled down.
• Lock the shutter before starting the work, unlock the
shutter only after finishing the work.
• Always keep the floor around the probe gas sampling
system clean and dry.
Explanation of safety measures: Safety instructions for
maintenance work on page 98.
Maintenance interval
• as required (e.g., after kiln conversion work, civil works,
structural changes of kiln inlet area, or process changes)
Instructions: checking the probe tip position and insertion
depth
Due to changes entailed by the process or the system, it may be
necessary to change the position of the gas sampling probe.
Note that the tip of the probe should be maximum 30 cm inside
the rotary kiln (beyond the kiln seal) after start-up. The gas
sampling probe must not be inserted further than absolutely
necessary into the rotary kiln in order to minimize impacts on
the unprotected area of the probe caused by the process.
When defining the measuring point, a comparison of the probe
insertion depth to the measurement of oxygen must be
performed in order to find the best position. This evaluation
must be done at a time where the kiln operation is stable and at
a normal operation state, i.e., normal cement throughput.
When starting to evaluate the oxygen concentration compared
to the depth of the probe, start with the probe only just entering
the process with the probe tip. At this point false air from the
insertion flange together with the false air from the kiln sealing
will result in a high oxygen reading.
Gradually go deeper inside the process in steps of approximately
0,25m. The first couple of steps will not make any defined
difference. However, at one point the oxygen will drop. Take a
note of this point and then go one or two steps further inside as
needed, in order to get a stable oxygen reading. Take note of
this point as the S3 measuring point for the retractor.
The typical insertion depth will depend on the amount of false
air entering the riser duct from the kiln sealing. It is not normal
that the sample end of the probe needs to go all the way inside
the kiln. Typically, 1m free, away from any wall surface will be
enough.
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