In the newer type (which was first proposed by Andrews for the combustion of gases) the chemical action takes place in a completely closed combustion chamber of sufficient strength to resist the pressure generated by the sudden action, which is often of explosive violence.
The procedure for a combustion is as follows: - FIG.
In the older type the combustion chamber (of metal or glass) is sunk in the calorimeter proper, tubes being provided for the entrance and exit of the gaseous substances involved in the action.
Mayow had suggested the existence of two components, a spiritus nitroaerus which supported combustion, and a spiritus nitri acidi which extinguished fire; J.
The phlogistic theory, which pervaded the chemical doctrine of this period, gave rise to continued study of the products of calcination and combustion; it thus happened that the knowledge of oxides and oxidation products was considerably developed.
The best form of stove is that with which perfect combustion is most nearly attained, and to which a pan of water is affixed to supply a desirable humidity to the air, the gas having the effect of drying the atmosphere.
Charcoal, coke or anthracite coal are the fuels generally used in slow combustion heating stoves.
That vigorous chemical action is accompanied by a brisk evolution of heat is evident from such familiar examples as the combustion of fuel or the explosion of gunpowder.
Thomsen then investigated heats of combustion of various benzenoid hydrocarbons - benzene, naphthalene, anthracene, phenanthrene, &c. - in the crystallized state.
Its fires are not volcanic, but result from the combustion of coal some distance underground, giving off much smoke and steam; geologists estimate that the burning has been going on for at least 800 years.
The accuracy of heats of combustion determined in the closed calorimeter is in favourable cases about one-half per cent.
With exceptionally bad weather the load would have to be reduced or two engines would have to be employed, or an exceptionally high rate of combustion would have to be maintained in the fire-box.
The steel combustion chamber is of about 250 c.c. capacity, and is wholly immersed in the calorimeter.
In the choice of a boiler of this description it should be remembered that rapid heating, economical combustion of fuel, and facilities for cleaning, are requisites, the absence of any of which considerably lowers the efficiency of the apparatus.
Carbon and hydrogen are generally estimated by the combustion process, which consists in oxidizing the substance and absorbing the products of combustion in suitable apparatus.
The draught corresponding to the smallest rate of combustion shown in Table XX.
Difficultly volatile liquids may be weighed directly into the boat; volatile liquids are weighed in thin hermetically sealed bulbs, the necks of which are broken just before they are placed in the combustion tube.
In the first method the substance, mixed with quicklime free from chlorine, is heated in a tube closed at one end in a combustion furnace.
According to Liebig, man's body is a stove, and food the fuel which keeps up the internal combustion in the lungs.
With closed stoves much less heat is wasted, and consequ;ntly less fuel is burned, than with open grates, but they often cause an unpleasant sensation of dryness in the air, and the products of combustion also escape to some extent, rendering this method of heating not only unpleasant but sometimes even dangerous.
Sublimed sulphur also results from the spontaneous combustion of coal seams containing pyrites.
By the combustion of the least sufficient quantity of sulphur, the rest is liquefied.
When compressed it is also used largely as a refrigerating agent, and in virtue of its property of neither burning nor supporting combustion it is also used as a fire extinctor.
The Rocket possessed the three elements of efficiency of the modern locomotive - the internal water-surrounded fire-box and the multitubular flue in the boiler; the blast-pipe, by which the steam after doing its work in the cylinders was exhausted up the chimney, and thus served to increase the draught and promote the rapid combustion of the fuel; and the direct connexion of the steam cylinders, one on each side of the engine, with the two driving wheels mounted on one axle.
- The resistance against which a train is moved along a railway is overcome by means of energy obtained from the combustion of fuel, or in some few cases by energy obtained from a waterfall.
Produced by the combustion of 1 lb of coal, 15,000 Xo 06 =900 only are available for tractive purposes.
- One pound of coal requires about 20 lb of air for its proper combustion in the fire-box of a locomotive, though this quantity of air diminishes as the rate of combustion increases.
Ft., that the rate of combustion is 150 lb of coal per square foot of grate per hour, that the calorific value is 14000, and finally that n =0.06, the maximum indicated horse-power which the engine might be expected to develop would be o 06 X 150 x14000 X24 X 778/1980000 = I 190, corresponding to a mean effective pressure in the cylinders of 59.5 lb per square inch.
Combustion calorimeters are employed for observing the heat generated by the brisk interaction of substances, one of which at least is gaseous.
A much better approximation to the heat of combustion of such substances is obtained by deducting the oxygen together with the amount of carbon necessary to form C02, and then ascertaining the amount of heat produced by the residual carbon and hydrogen.
Combustion meant the liberation of phlogiston..
At the hands of Stahl and his school, the phlogistic theory, by exhibiting a fundamental similarity between all processes of combustion and by its remarkable flexibility, came to be a general theory of chemical action.
It is well known that singly, doubly and trebly linked carbon atoms affect the physical properties of substances, such as the refractive index, specific volume, and the heat of combustion; and by determining these constants for many substances, fairly definite values can be assigned to these groupings.
The heat of combustion, as first determined by Julius Thomsen, agreed rather better with the presence of nine single unions.
Stohmann of Leipzig; and the new data and the conclusions to be drawn from them formed the subject of much discussion, Briihl endeavouring to show how they supported Kekule's formula, while Thomsen maintained that they demanded the benzene union to have a different heat of combustion from the acetylene union.
At the same time a little trioxide is formed, and, according to Hempel (Ber., 1890, 2 3, p. 1 455), half the sulphur is converted into this oxide if the combustion be carried out in oxygen at a pressure of 40 to 50 atmospheres.
- The maximum power which can be developed by a locomotive depends upon the maximum rate of fuel combustion which can be maintained per square foot of grate.
The maximum rate of combustion may be as much as so lb of coal per square foot of grate per hour, and in exceptional cases even a greater rate than this has been maintained.
It is not economical to force the boiler to work at too high a rate, because it has been practically demonstrated that the boiler efficiency decreases after a certain point, as the rate of combustion increases.
A few experimental results are set forth in Table XX., from which it will be seen that with a relatively low rate of combustion, a rate which denotes very light service, namely lb of coal per square foot of grate per hour, the efficiency of the boiler is %, which is as good a result as can be obtained with the best class of stationary boiler or marine boiler even when using economizers.
The relation between the heat of combustion of a hydrocarbon and its heat of formation may be readily seen from the following example.
The oxygen contained in the compound was deducted, together with the equivalent amount of hydrogen, and the heat of combustion of the compound was then taken to be equal to the heats of combustion of the elements in the residue.
The observed heat of combustion of sugar is, however, 1354000, so that the error of the rule is here 20 per cent.
Different from the observed heat of combustion of sugar.
Chladni's experiment of strewing a vibrating bell with flour, investigated the nature of sound and the function of the air in respiration and combustion, and originated the idea of using the pendulum as a measure of gravity.
Was primarily based upon certain experiments on combustion and calcination, and in effect reduced the number of the alchemical principles, while setting up a new one, a principle of combustibility, named phlogiston (from (PXoyun-6s, burnt).
He established as fundamental that combustion and calcination were attended by an increase of weight, and concluded, as did Jean Rey and John Mayow in the 17th century, that the increase was due to the combination of the metal with the air.
Thorpe's investigation of the products of the slow combustion of phosphorus.
Theoretical speculations were revived by Lavoisier, who, having explained the nature of combustion and determined methods for analysing compounds, concluded that vegetable substances ordinarily contained carbon, hydrogen and oxygen, while animal substances generally contained, in addition to these elements, nitrogen, and sometimes phosphorus and sulphur.
The violence or completeness of combustion was proportional to the amount of phlogiston present.