Part 8 (1/2)
[Illustration: 1456 Horse-power Installation of Babcock & Wilcox Boilers at the Raritan Woolen Mills, Raritan, N J The First of These Boilers were Installed in 1878 and 1881 and are still Operated at 80 Pounds Pressure]
Durability--Babcock & Wilcox boilers are being operated in every-day service with entirely satisfactory results and under the sainally sold that have been operated fro to note in considering the life of a boiler that the length of life of a Babcock & Wilcox boiler th of life is possible This is due to the fact that there are Babcock & Wilcox boilers in operation to-day that have been in service froin that at which the manufacturer of any other water-tube boiler now on the market was started
Probably the very best evidence of the value of the Babcock & Wilcox boiler as a steaenerator and of the reliability of the apparatus, is seen in the sales of the company Since the cohout the world over 9,900,000 horse power
A feature that cannot be overlooked in the consideration of the advantages of the Babcock & Wilcox boiler is the fact that as a part of the organization back of the boiler, there is a body of engineers of recognized ability, ready at all times to assist its customers in every possible way
[Illustration: 2400 Horse-power Installation of Babcock & Wilcox Boilers in the Union Station Power House of the Pennsylvania Railroad Co, Pittsburgh, Pa This Company has a Total of 28,500 Horse Power of Babcock & Wilcox Boilers Installed]
HEAT AND ITS MEASUREMENT
The usual conception of heat is that it is a fory produced by the vibratory motion of the minute particles or molecules of a body All bodies are assuether by mutual cohesion and yet are in a state of continual vibration The hotter a body or the orous will be the vibrations of the molecules
As is well known, the effect of heat on a body e its temperature, its volume, or its state, that is, froaseous Where water is es are admirably described in the lecture by Mr Babcock on ”The Theory of Steae in temperature of a body is ordinarily h temperatures so-called pyro ”High Temperature Measure 11]
By reason of the uniforreat sensitiveness to heat, it is the fluid most commonly used in the construction of ther point and the boiling point of water, under e atmospheric pressure at sea level, are assumed as two fixed points, but the division of the scale between these two points varies in different countries The freezing point is deter ice and for this reason is often called thepoint There are in use three therrade or Celsius, and the Reau 11, in the Fahrenheit scale, the space between the two fixed points is divided into 180 parts; the boiling point ispoint is marked 32, and zero is a temperature which, at the tiined to be the lowest terade and the Reaumur scales, the distance between the two fixed points is divided into 100 and 80 parts, respectively In each of these two scales the freezing point is rade and 80 in the Reaumur Each of the 180, 100 or 80 divisions in the respective therree
Table 3 and appended for from one scale to another
In the United States the bulbs of high-grade thermometers are usually lass or Jena 16{III} glass, the stelass is not suitable for use at terees Fahrenheit and the harder Jena 59{III} should be used in therher than this
Below the boiling point, the hydrogen-gas thermometer is the almost universal standard hich mercurial theren-gas there in tee in pressure of a constant volu a mercurial therree is represented as 1/180 part of the volu point of ice and the boiling point of water For terees of the same voluraduated to read true-gas-scale teas therree intervals Each degree is then 1/25 or 1/50 of the volume of the stem in each interval
Every ther point, should be suitably annealed before it is used If this is not done, the truepoint and also the ”funda and the boiling points, her tee, so that the thermometer s
TABLE 3
COMPARISON OF THERMOMETER SCALES
+---------------+----------+----------+----------+ | |Fahrenheit|Centigrade| Reaumur | +---------------+----------+----------+----------+ |Absolute Zero | -45964 | -27313 | -21850 | | | 0 | -1778 | -1422 | | | 10 | -1222 | -978 | | | 20 | -667 | -533 | | | 30 | -111 | -089 | |Freezing Point | 32 | 0 | 0 | |Maximum Density| | | | | of Water | 391 | 394 | 315 | | | 50 | 10 | 8 | | | 75 | 2389 | 1911 | | | 100 | 3778 | 3022 | | | 200 | 9333 | 7467 | |Boiling Point | 212 | 100 | 80 | | | 250 | 12111 | 9689 | | | 300 | 14889 | 11911 | | | 350 | 17667 | 14133 | +---------------+----------+----------+----------+
F = 9/5C+32 = 9/4R+32
C = 5/9(F-32) = 5/4R
R = 4/9(F-32) = 4/5C
As a general rule therraduated to read correctly for total immersion, that is, with bulb and stem of the thermometer at the same temperature, and they should be used in this hen coes into space either hotter or colder than that in which the bulb is placed, a ”stem correction” must be applied to the observed temperature in addition to any correction that may be found in the comparison with the standard For instance, for a particular thermometer, comparison with the standard with both fully i corrections:
_Temperature_ _Correction_ 40F 00 100 00 200 00 300 +25 400 -05 500 -25