5 PRT Care and HandlingGuidelines5.1 PRT Care
CAUTION: R EAD THIS SECTI ON BEFORE REM OVING THE PRT
FROM THE SHI PPING BOX OR CASE
The 5626 and 5628 Platinum Resistance Thermometers (PRTs) are delicate
instruments. Care must be taken in handling the PRTs to maintain calibra-
tion accuracy.T he stress free design of the PRT sensor reduces the effects of
mechanical shock. In addition, contamination problems of the sensor at high
temperature have been eliminated. However, care should still be used when
handling the PRT even though the Inconel sheath is durable and provides
good protection for the sensor.Correct handling of the PRT w ill prolong the
life expectancy.When not in use, the P RTshould b e stored in the protective
case provided by Hart.
Note: The PRT sheath changes color after use at high temperatures.
The PRT may arrive with a brown tint to the sheath due to calibration
at high temperatures.
The handle is not designed to be immersed. The temperature limits of the
handle are: 0°C to 80°C. Temperaturesoutside these limits can damage the
sealed portion of the handle and the connectors.
5.2 PRT Handling Guidelines
•DO anneal the thermometer after shipment. Shipping the thermometer
can cause mechanical shocks that effect the accuracy of the thermome-
ter. Therefore, if possible, we advise that the thermometer be annealed
before use. The thermometer should be annealed at 500°C overnight
or 660°C for four (4) hours.
•DO keep the thermometer as clean as possible. Always remove any
fluid from the sheath immediately after taking the thermometer from a
bath.
•DO immerse the thermometer in the appropriate liquid for the temper-
ature range. If a dry block is used, the well diameter should allow the
PRT to comfortably slip in and out without excess movement. For best
results, immerse the thermometer as deep as possible to avoid “stem
effect” (the temperature error caused by the conduction of heat away
from the sensor). Do not submerge the handles.
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PRT Care and Handling Guidelines