PYROMETRY AND PYROMETERS
In order to give definite information concerning furnaces, fuels
etc., the following data is quoted from a paper by Seth A. Moulton
and W. H. Lyman before the Steel Heat Treaters Society in September,
Pyrometry And Pyrometers
A knowledge of the fundamental principles of pyrometry, or the
measurement of temperatures, is quite necessary for one engaged
in the heat treatment of steel. It is only by careful measurement
and control of the he...
Armor plate makers sometimes use the copper ball or Siemens' water
pyrometer because they can place a number of the balls or weights on
the plate in locations where it is difficult to use other pyrometers.
One of t...
With the application of the thermo-couple, the measurement of
temperatures, between, say, 700 and 2,500 deg.F., was made more simple
and precise. The theory of the thermo-couple is simple; it is that
if two bars, r...
The Pyrometer And Its Use
In the heat treatment of steel, it has become absolutely necessary
that a measuring instrument be used which will give the operator an
exact reading of heat in furnace. There are a number of instruments
Calibration Of Pyrometer With Common Salt
An easy and convenient method for standardization and one which
does not necessitate the use of an expensive laboratory equipment
is that based upon determining the melting point of common table
salt (sodium chlori...
Complete Calibration Of Pyrometers
For the complete calibration
of a thermo-couple of unknown electromotive force, the new couple
may be checked against a standard instrument, placing the two bare
couples side by side in a suitable tube and taking f...
Placing Of Pyrometers
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 i...
The Leeds And Northrup Potentiometer System
The potentiometer pyrometer system is both flexible and substantial
in that it is not affected by the jar and vibration of the factory
or the forge shop. Large or small couples, long or short leads
can be used with...
Placing The Thermo-couples
The following illustrations from the Taylor Instrument Company
show different applications of the thermo-couples to furnaces of
various kinds. Figure 118 shows an oil-fired furnace with a simple
Leeds And Northrup Optical Pyrometer
The principles of this very popular method of measuring temperature
are sketched in Fig. 123.
The instrument is light and portable, and can be sighted as easily
as an opera glass. The telescope, which is hel...
Optical System And Electrical Circuit Of The Leeds & Northrup Optical Pyrometer
For extremely high temperature, the optical pyrometer is
largely used. This is a comparative method. By means of the rheostat
the current through the lamp is adjusted until the brightness of
the filament is just eq...
Correction For Cold-junction Errors
The voltage generated by a thermo-couple of an electric pyrometer is
dependent on the difference in temperature between its hot junction,
inside the furnace, and the cold junction, or opposite end of the
Correction By Zero Adjustment
Many pyrometers are supplied with
a zero adjuster, by means of which the pointer can be set to any
actual cold-junction temperature. If the cold junction of the
thermo-couple is in a temperature of 100 deg.F., the ...
By the use of compensating leads, formed of
the same material as the thermo-couple, the cold junction can be
removed from the head of the thermo-couple to a point 10, 20 or 50
ft. distant from the furnace, where th...
Brown Automatic Signaling Pyrometer
In large heat-treating plants it has been customary to maintain
an operator at a central pyrometer, and by colored electric lights
at the furnaces, signal whether the temperatures are correct or
not. It is common p...
An Automatic Temperature Control Pyrometer
Automatic temperature control instruments are similar to the Brown
indicating high resistance pyrometer with the exception that the
pointer is depressed at intervals of every 10 sec. upon contact-making
Pyrometers For Molten Metal
Pyrometers for molten metal are connected to portable thermocouples
as in Fig. 132. Usually the pyrometer is portable, as shown in
this case, which is a Brown. Other methods of mounting for this
kind of work arc sh...
Protectors For Thermo-couples
Thermo-couples must be protected from the danger of mechanical
injury. For this purpose tubes of various refractory materials
are made to act as protectors. These in turn are usually protected
by outside metal tube...