Placing Of Pyrometers
: PYROMETRY AND PYROMETERS: The Working Of Steel
When installing a pyrometer, care should be
taken that it reaches directly to the point desired to be measured,
that the cold junction is kept cold, and that the wires leading to
the recording instrument are kept in good shape. The length of
these lead wires have an effect; the longer they are, the lower
the apparent temperature.
When pyrometers placed in a number of furnaces are connected up
apparent that pyrometers could not be interchanged between furnaces
near and far from the instrument without affecting the uniformity
of product from each furnace.
Calibration can best be done without disturbing the working pyrometer,
by inserting the master instrument into each furnace separately, place
it alongside the hot junction of the working pyrometer, and compare
the reading given on the indicator connected with the multiple
switch.
Protection tubes should be replaced when cracked, as it is important
that no foreign substance is allowed to freeze in the tube, so
that the enclosed junction becomes a part of a solid mass joined
in electrical contact with the outside protecting tube. Wires over
the furnaces must be carefully inspected from time to time, as no
true reading can be had on an instrument, if insulation is burned
off and short circuits result.
If the standard calibrating instrument used contains a dry battery,
it should be examined from time to time to be sure it is in good
condition.
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