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Annealing To Relieve Internal Stresses
Work quenched from a high temperature and not afterward tempe...

S A E Heat Treatments
The Society of Automotive Engineers have adopted certain heat...

Placing The Thermo-couples
The following illustrations from the Taylor Instrument Compan...

Crankshaft
The crankshaft was the most highly stressed part of the entir...

Manganese
MANGANESE is a metal much like iron. Its chemical symbol is M...

Annealing Of High-speed Steel
For annealing high-speed steel, some makers recommend using g...

Carburizing By Gas
The process of carburizing by gas, briefly mentioned on page ...

Corrosion
This steel like any other steel when distorted by cold worki...

Temperature Recording And Regulation
Each furnace is equipped with pyrometers, but the reading an...

Drop Forging Dies
The kind of steel used in the die of course influences the he...

Annealing
ANNEALING can be done by heating to temperatures ranging from...

Plant For Forging Rifle Barrels
The forging of rifle barrels in large quantities and heat-tre...

An Automatic Temperature Control Pyrometer
Automatic temperature control instruments are similar to the ...

Silicon
SILICON is a very widespread element (symbol Si), being an es...

Chrome-nickel Steel
Forging heat of chrome-nickel steel depends very largely on ...

Blending The Compound
Essentially, this consists of the sturdy, power-driven separa...

Ebbw Vale And The Bessemer Process
After his British Association address in August 1856, Besseme...

William Kelly's Air-boiling Process
An account of Bessemer's address to the British Association w...

Classifications Of Steel
Among makers and sellers, carbon tool-steels are classed by g...

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



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.





Next: Correction For Cold-junction Errors

Previous: Leeds And Northrup Optical Pyrometer



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