Steam, Its Generation and Use

Name: Steam, Its Generation and Use
Author: Babcock & Wilcox Company

Babcock & Wilcox Company

Steam-boilers, Water-tube

Optical Pyrometers--Of the optical pyrometers the Wanner is perhaps the
most reliable. The principle on which this instrument is constructed is
that of comparing the quantity of light emanating from the heated body
with a constant source of light, in this case a two-volt osmium lamp.
The lamp is placed at one end of an optical tube, while at the other an
eyepiece is provided and a scale. A battery of cells furnishes the
current for the lamp. On looking through the pyrometer, a circle of red
light appears, divided into distinct halves of different intensities.
Adjustment may be made so that the two halves appear alike and a reading
is then taken from the scale. The temperatures are obtained from a table
of temperatures corresponding to scale readings. For standardizing the
osmium lamp, an amylacetate lamp, is provided with a stand for holding
the optical tube.

                TABLE 8

APPROXIMATE MELTING POINTS OF METALS[8]

+-----------------+------------------+
|    Metal        |    Temperature   |
|                 |Degrees Fahrenheit|
+-----------------+------------------+
|Wrought Iron     |       2737       |
|Pig Iron (gray)  |     2190-2327    |
|Cast Iron (white)|       2075       |
|Steel            |     2460-2550    |
|Steel (cast)     |       2500       |
|Copper           |       1981       |
|Zinc             |        786       |
|Antimony         |       1166       |
|Lead             |        621       |
|Bismuth          |        498       |
|Tin              |        449       |
|Platinum         |       3191       |
|Gold             |       1946       |
|Silver           |       1762       |
|Aluminum         |       1216       |
+-----------------+------------------+


Determination of Temperature from Character of Emitted Light--As a
further means of determining approximately the temperature of a furnace,
Table 9, compiled by Messrs. White & Taylor, may be of service. The
color at a given temperature is approximately the same for all kinds of
combustibles under similar conditions.

                       TABLE 9

    CHARACTER OF EMITTED LIGHT AND CORRESPONDING
             APPROXIMATE TEMPERATURE[9]

+--------------------------------------+-----------+
|      Character of Emitted Light      |Temperature|
|                                      |  Degrees  |
|                                      | Fahrenheit|
+--------------------------------------+-----------+
|Dark red, blood red, low red          |   1050    |
|Dark cherry red                       |   1175    |
|Cherry, full red                      |   1375    |
|Light cherry, bright cherry, light red|   1550    |
|Orange                                |   1650    |
|Light orange                          |   1725    |
|Yellow                                |   1825    |
|Light yellow                          |   1975    |
|White                                 |   2200    |
+--------------------------------------+-----------+




THE THEORY OF STEAM MAKING

Public-domain text, read in full here on John Shaqi.

Steam, Its Generation and Use

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