Fluke Datapaq Furnace Tracker User Manual page 10

Heatsinks have a temperature-sensitive label to provide indication of the
maximum temperature experienced by the data logger, and a warning should
the temperature exceed 77°C/170°F. This warning is important: see p. 17.
The Microporous insulation material will absorb moisture if stored in a damp
environment. Although this will not result in damage to the thermal barrier, its
performance will be degraded until the moisture is removed.
All Datapaq thermal barriers for furnace use have an adjustable lid to
compensate for any shrinkage of insulation material, and TB4900 and most
TB4000 series barriers (see below) also have provision for renewal of the
Mullite fiber used to clamp the thermocouple cables (see p. 18). Thermal
barriers with lid secured by catches have adjustment in the catches to
compensate for shrinkage (see p. 17).
Materials used for any fasteners in the TB4900 series barriers (nuts and bolts)
are normally 310 stainless steel, and are selected to avoid seizure at high
temperature.
Selecting the Thermal Barrier
The selection of barrier type depends principally on the height and width
limitations of the furnace, the data logger type, process duration, temperature,
time at temperature, furnace atmosphere and whether the process includes a
quench cycle.
When assessing the barrier's required thermal performance, include within the
overall process duration the time taken to retrieve the Tracker system from the
furnace and to remove the data logger from the barrier.
Consult Fluke Process Instruments for advice on selecting a thermal barrier.
When changing the parameters of your process, be aware that using your
thermal barrier for conditions other than originally specified (i.e. longer
durations and/or higher temperatures) may cause serious damage to all parts of
your Datapaq system. We strongly advise you to contact Fluke Process
Instruments to confirm that your system is suitable for your new process. You
will require the following information about the new process:
• Heating phase (time to reach soak temperature).
• Soak time and temperature.
• Cooling phase (time from soak temperature to end of process).
• Furnace atmosphere.
• Time from end of cooling phase to removal of the thermal barrier and
dismantling of the system.
10
Basic Hardware
FURNACE TR ACK ER