Super Systems Gold Probe - Manual (Page 8)

7
SSi Gold Probe Manual Rev C
Maintenance (con’t)
The reason this technique is superior is that the
carbon retained in the pores of the refractory is
what constitutes “seasoning”. Complete burnout,
however gentle, removes this carbon and
requires that it be added during a Monday
morning start-up seasoning routine, in order to
achieve operating levels.
Probe conditioning: While periodic furnace
burnout is desirable, the process by which solid
carbon or ‘soot’ is deposited continues in the
probe, and must be remedied more frequently to
keep the probe in peak operating condition. SSi
technical staff has pioneered in techniques to
achieve this. Soot deposition occurs in two
critical locations; the annular space between the
sheath and the measuring surface and at the
measuring junction between the zirconia and the
contact point with the sheath, which is the
measuring electrode. The probe is burnt out by
the flowing air into this space through the
burnout fitting provided. The flow of air must be
set at a rate that allows a temperature rise of no
more than 100 degrees Farenheit (38 degrees
Celsius). If possible the flow should be set high
enough to overcome the effect of the work
chamber fan and drop the output voltage well
below 200 MV. Conducting this process for a 90
second period before or after each batch, or
every six to twelve hours in a continuous furnace,
will provide adequate conditioning in most cases.
See Fig. 6.
TYPICAL PROBE BURNOUT SYSTEM
Fig. 6