Steam:
Its Generation and Use

Engineering Office of Chas. E. Emery, No. 7 Warren Street, New York, March 21, 1879. Messrs. Babcock & Wilcox, No. 30 Cortlandt Street, New York. Gentlemen : On the 4th and 5th of Febru- ary, 1879, I made a trial of the Babcock & Wil- cox Boilers and Corliss engines in the Raritan Woolen Mills, Raritan, N. J., the results of which are shown in the following report: There were two boilers tested of the water- tube type, manufactured by you and known by your name, rated jointly at 360 horse-power, and reported to contain 4,080 square feet of heating surface, and 103 square feet of grate surface. These boilers were erected side by side and connected so that they could be used separately or conjointly in connection with or independent of a number of Lancashire drop-flue boilers, three boilers of the latter kind having been re- moved to make room for yours. All the boilers were connected to a single chimney through a Green’s economizer in the flue. A large por- tion of the steam generated appeared to be used in the dye house and for heating pur- poses. A portion of the boilers were employed, however, to supply steam to two pairs of en- gines, of equal size, operating the mill, one pair being of the Wright patent, put in many years since, and the other of Corliss make, erected within a year. Each steam cylinder was 20 in- ches in diameter with 48 inches stroke of piston. The engines are provided with Bulkley conden- sers. In the ordinary working of the mill your boilers were used to supply steam to both pairs of engines. Your contract contained a guarantee that the boilers should furnish sufficient steam to de- velop the rated power (360 H. P.) in a Corliss engine, and that the evaporation should equal at least 9 pounds of water from a temperature of 1800 per pound of coal containing not more than 12 per cent, of refuse. In a preliminary trial, part of the load on the Wright engines was transferred to the Corliss engines; but it was soon found that the latter did not require all the steam your boilers would generate eco- nomically ; so two trials were made, one of 4J hours’ duration, using your boilers with reduced draft to supply steam to the Corliss engines only, and taking data to ascertain the economy of the engines ; the other of fully 12 hours’ du- ration, using the boilers at maximum power on a dull day without forcing the fires, part of the steam being used to operate the Corliss engines, the remainder blown into the pipe system of the other boilers, which were working at a much less pressure. Trial of the Boilers. The experiment commenced at 6.01 A. m., and closed at 6.38 p. m. In starting, steam was raised by spreading the banked fires left from the previous day. When the pressure reached 80 pounds the fires were hauled, all refuse re- moved, and fires started anew with wood, which in calculation has been considered equal in calorific value to its weight of coal'. The fires were maintained with coal during the day, finally hauled, allowed to cool, the combustible portion deducted from the coal charged, and the refuse weighed separately. The experi- ment was closed when the boilers stopped making steam at 80 lbs. pressure, with water in the glass gauges at same height as in starting. During the trial, all the coal consumed was weighed in an iron wheel-barrow, balanced when empty by a fixed weight, and each bar- row load was adjusted at the scale to weigh 200 pounds net. All the water evaporated was measured in a tank provided with a heavy float connected through a fine chain to an index showing a water level on an exterior scale, divided decimally. By weighing water out of the tank, its capacity was found to be 5,172 pounds of water between the limits employed. A complete record was kept of the coal, water, steam pressure and various temperatures, and the quality of the steam was tested with a calorime- ter at frequent intervals. The proprietors of the mill took the proper business precaution of stationing observers at each point, who kept 81