Steam boilers, their construction, care and operation; with questions and answers

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1913 Excerpt: ...heat--Experiments of Professor Black--Total heat of evaporation--Water, its composition, nature, etc.--Steam, its expansive nature, temperature, etc.--Saturated steam, etc.--Total heat of steam--Density of steam. Combustion. The subject of the combustion of fuels being one in which every engineer is vitally interested, it is proper that its leading features and principles be discussed. One of the main factors in the combustion of coal is the proper supply of air. Air is composed of two gases, oxygen and nitrogen, in the proportion, by volume, of 21 per cent. of oxygen and 79 per cent. of nitrogen, or by weight, 23 per cent. of oxygen and 77 per cent. of nitrogen. The composition of pure dry air, as given by Kent in Steam Boiler Economy, is as follows: By volume, 20.91 parts O. and 79.09 parts N. By weight, 23.15 parts O. and 76.85 parts N. Air is a mixture and not a chemical combination of these two elements. The principal constituent of coal and most other fuels, whether solid, liquid or gaseous, is carbon. Hydrogen is a light combustible gas and combined either with carbon or with carbon and oxygen, in various proportions, is also a valuable constituent of fuels, notably of bituminous coal. The heating value of one pound of pure carbon is rated at 14,500 heat units, while one pound of hydrogen gas contains 62,000 heat units. Analysis of coal shows that it. contains moisture, fixed carbon, volatile matter, ash and sulphur in various proportions according to the quality of the coal. The following table deduced from a few of the many valuable tables of analysis of the coals of the United States, as given by Mr. Kent, will show the composition of the principal bituminous coals in use in this country for steam purposes. Two samples are selected from each of th...