Part 23 (2/2)

Table 39 gives for comparison the ultimate and proximate analyses of certain of the coals hich tests were ical Survey at the Louisiana Purchase Exposition at St Louis

The heating value of a fuel cannot be directly computed from a proximate analysis, due to the fact that the volatile content varies widely in different fuels in co value

So the calorific value of coals from the proximate analysis William Kent[38] deducted fro value dependent upon the content of fixed carbon in the combustible The relation as deduced by Kent between the heat and value per pound of combustible and the per cent of fixed carbon referred to co 23

Goutal gives anotherthe heat value froiven a fixed value and the heating value of the volatile e referred to combustible Goutal's method checks closely with Kent's deter the calorific value of coals from a proximate analysis are ordinarily limited to certain classes of fuels Mr Kent, for instance, states that his deductions are correct within a close li more than 60 per cent of fixed carbon in the coe, the error h or low

While the use of such computations will serve where approximate results only are required, that they are approxihly understood

Calorimetry--An ultimate or a proxieneral characteristics, and as described on page 183,value Where the efficiency of a boiler is to be co value should in all instances be determined accurately by means of a fuel caloriainst Per Cent of Fixed Carbon in Co 23 Graphic Representation of Relation between Heat Value Per Pound of Combustible and Fixed Carbon in Combustible as Deduced by Wm Kent]

In such an apparatus the fuel is coenerated by such co calculated from the elevation in the temperature of the water A calorimeter which has been accepted as the best for such work is one in which the fuel is burned in a steel boen

The function of the oxygen, which is ordinarily under a pressure of about 25 atmospheres, is to cause the rapid and conited byof the fuse wire

A caloriive satisfactory results is that of M Pierre Mahler, illustrated in Fig 24 and consisting of the following parts:

A water jacket A, which maintains constant conditions outside of the calorimeter proper, and thus makes possible a more accurate computation of radiation losses

The porcelain lined steel bomb B, in which the coen

[Illustration: Fig 24 Mahler Bo the fuel

The calori a definite weighed a with the fuse wire F, for igniting the fuel placed in the pan C

A support G, for a water agitator

A thermometer I, for temperature determination of the water in the calorimeter The thermometer is best supported by a stand independent of the calorimeter, so that it may not be moved by tremors in the parts of the caloris difficult To obtain accuracy of readings, they should beand screw device for revolving the agitator

A lever L, by the auge M, for noting the aen admitted to the bomb Between 20 and 25 aten tank O

A battery or batteries P, the current fronite the fuel

This or a similar calorimeter is used in the determination of the heat of combustion of solid or liquid fuels Whatever the fuel to be tested, too e sample Where coal is to be tested, tests should be made from a portion of the dried and pulverized laboratory sa which have been described In considering the methods of calorimeter determination, the remarks applied to coal are equally applicable to any solid fuel, and such changes in methods as are necessary for liquid fuels will be self-evident froram of the pulverized dried coal sample should be placed directly in the pan of the calori of a pulverized sample from the fact that soen is ad about two grams into a briquette by the use of a cylinder equipped with a plunger and a screw press Such a briquette should be broken and approxiram used If a pulverized saen slowly to prevent blowing the coal out of the pan The weight of the saram since the caloriht when under an oxygen pressure of about 25 atmospheres

A piece of fine iron wire is connected to the lower end of the plunger to forht of iron wire used is determined, and if after coht of such portion is deter the fuse, the top of the calorimeter is removed It is then replaced and carefully screwed into place on the bo handled wrench furnished for the purpose

The bomb is then placed in the calorimeter, which has been filled with a definite aht is the ”water equivalent” of the apparatus, _i e_, the weight of water, the teree for an equivalent increase in the temperature of the combined apparatus It hts and specific heats of the various parts of the apparatus Such a deterht of the bo can only be approximated, and a considerable portion of the apparatus is not sub such a deterhts of ater to definite ae of a nu of such a deter of a definite amount of resublimed naphthaline whose heat of combustion is known

The temperature of the water in the water jacket of the calori athed amount of water in the calorireater than that of the surrounding air in order that the initial correction for radiation will be in the same direction as the final correction Other experihtly lower than the temperature of the room, on the basis that the teher than the room temperature and the radiation correction be either a minimum or entirely eliminated