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

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

Pyrometers
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Restoring Overheated Steel
The effect of heat treatment on overheated steel is shown gra...

Liberty Motor Connecting Rods
The requirements for materials for the Liberty motor connecti...

Non-shrinking Oil-hardening Steels
Certain steels have a very low rate of expansion and contract...

Protectors For Thermo-couples
Thermo-couples must be protected from the danger of mechanica...

Tempering Round Dies
A number of circular dies of carbon tool steel for use in too...

Annealing
There is no mystery or secret about the proper annealing of d...

Quality And Structure
The quality of high-speed steel is dependent to a very great ...

Open Hearth Process
The open hearth furnace consists of a big brick room with a l...

Furnace Data
In order to give definite information concerning furnaces, fu...

Separating The Work From The Compound
During the pulling of the heat, the pots are dumped upon a ca...

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

Double Annealing
Water annealing consists in heating the piece, allowing it to...

Temperature For Annealing
Theoretically, annealing should be accomplished at a tempera...

Process Of Carburizing
Carburizing imparts a shell of high-carbon content to a low-...

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

Crucible Steel
Crucible steel is still made by melting material in a clay or...

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



Leeds And Northrup Optical Pyrometer






Category: PYROMETRY AND PYROMETERS

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 held in the hand, weighs
only 25 oz.; and the case containing the battery, rheostat and
milliammeter, which is slung from the shoulder, only 10 lb.




A large surface to sight at is not required. So long as the image
formed by the objective is broader than the lamp filament, the
temperature can be measured accurately.


recorder.]



Distance does not matter, as the brightness of the image formed
by the lens is practically constant, regardless of the distance
of the instrument from the hot object.



The manipulation is simple and rapid, consisting merely in the turning
of a knurled knob. The setting is made with great precision, due to
the rapid change in light intensity with change in temperature and
to the sensitiveness of the eye to differences of light intensity.
In the region of temperatures used for hardening steel, for example,
different observers using the instrument will agree within 3 deg.C.


Only brightness, not color, of light is matched, as light of only
one color reaches the eye. Color blindness, therefore, is no hindrance
to the use of this method. The use of the instrument is shown in
Fig. 127.





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

Previous: Placing The Thermo-couples



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