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Conclusions
Martien was probably never a serious contender for the honor ...

Heat Treatment Of Gear Blanks
This section is based on a paper read before the American Gea...

Manganese
Manganese adds considerably to the tensile strength of steel,...

Protective Screens For Furnaces
Workmen needlessly exposed to the flames, heat and glare from...

Heavy Forging Practice
In heavy forging practice where the metal is being worked at...

The Effect Of Tempering On Water-quenched Gages
The following information has been supplied by Automatic and ...

Vanadium
Vanadium has a very marked effect upon alloy steels rich in c...

Steel Can Be Worked Cold
As noted above, steel can be worked cold, as in the case of ...

Instructions For Working High-speed Steel
Owing to the wide variations in the composition of high-speed...

Carbon Steels For Different Tools
All users of tool steels should carefully study the different...

Flange Shields For Furnaces
Such portable flame shields as the one illustrated in Fig. 1...

Leeds And Northrup Optical Pyrometer
The principles of this very popular method of measuring tempe...

Pyrometry And Pyrometers
A knowledge of the fundamental principles of pyrometry, or th...

Testing And Inspection Of Heat Treatment
The hard parts of the gear must be so hard that a new mill f...

Bessemer Process
The bessemer process consists of charging molten pig iron int...

Uses Of The Various Tempers Of Carbon Tool Steel
DIE TEMPER.--No. 3: All kinds of dies for deep stamping, pres...

Oil-hardening Steel
Heat slowly and uniformly to 1,450 deg.F. and forge thorough...

Pyrometers
Armor plate makers sometimes use the copper ball or Siemens' ...

Making Steel Balls
Steel balls are made from rods or coils according to size, st...

Silicon
Silicon prevents, to a large extent, defects such as gas bubb...



Optical System And Electrical Circuit Of The Leeds & Northrup Optical Pyrometer






Category: PYROMETRY AND PYROMETERS

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 equal to the brightness of the image produced
by the lens L, Fig. 123, whereupon the filament blends with or
becomes indistinguishable in the background formed by the image
of the hot object. This adjustment can be made with great accuracy
and certainty, as the effect of radiation upon the eye varies some
twenty times faster than does the temperature at 1,600 deg.F., and some
fourteen times faster at 3,400 deg.F. When a balance has been obtained,
the observer notes the reading of the milliammeter. The temperature
corresponding to the current is then read from a calibration curve
supplied with the instrument.



As the intensity of the light emitted at the higher temperatures
becomes dazzling, it is found desirable to introduce a piece of red
glass in the eye piece at R. This also eliminates any question
of matching colors, or of the observer's ability to distinguish
colors. It is further of value in dealing with bodies which do
not radiate light of the same composition as that emitted by a
black body, since nevertheless the intensity of radiation of any
one color from such bodies increases progressively in a definite
manner as the temperature rises. The intensity of this one color
can therefore be used as a measure of temperature for the body
in question. Figures 124 to 126 show the way it is read.





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Previous: Leeds And Northrup Optical Pyrometer



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