TYPES OF BOSTON PUMPING ENGINES
Among some of the big pumping engines built and installed by the Allis-Chalmers company, of Milwaukee, the 30,000,000-gal. engine now working in the Chestnut Hill high-service station of the Metropolitan waterworks of Boston is one of the finest manufactured bythat firm. Its installation was completed in December, 1898. It is of the vertical, triple-expansion, self-contained type, with three single-acting, outside-packed plungers, having at contract speed (about 175/2 revolutions per minute) a capacity of 30,000,01×1 U. S. gals, of water in twenty-four hours. The contract provided that the engine should perform a duty of 150,000,000 ft.-lbs. for each 1,000 lbs. of commercially dry steam used by the engine and auxiliary pumps, steam containing less than one and a half per cent, of entrained water, as determined by calorimeter measurement, to be considered as commercially dry steam; the work performed by the engine to be based upon pltm ger-displacement. The duty contracted for was performed, and considerably more, as the official test of the engine showed a duty of 178,497,000 ft.-lbs., which earned for tin* builders a bonus of $26,051.50 for economy over their guaranty. The diameter of the cylinders is 30-in., 56-in. and 87 in.; stroke, 66-in.; diameter of plungers, 42-in ; stroke of plungers, 66-in.; average revolution per min . 17.74; piston speed per min., 195.14 ft. The engine was fully described in FIRE AND WATER ENGINEERING of August 25.
The same firm has likewise installed four centrifugal pumps at the East Boston and Deer Island sewerage pumping stations for the city’s sewerage system and two in the Thirty-ninth street pumping station. Chicago, for pumping the sewage of that city. The duty guaranteed for the East Boston pumps by contract was 75.000,000 ft.-lbs.; developed by engine No. 1 was 91,104,390 ft.-lbs., by No. 2, 92,458,975 ft.-lbs., the company thus re ceiving a bonus. The Chicago Thirty-ninth street pumping station (Standard type 3 V. S. C.) has a capacity of 75 cu. ft. per second. This style oi pump, a very good illustration of which accompanies this notice, is built for handling large quantities of water under heads up to 40 ft., and is especially adapted for sewerage and drainage work. The pump sets horizontally on a vertical shaft and is submerged, thus obviating the use of foot-valves and priming pipes. The engine shown in the illustration is of the triple-expansion type, the three connecting rods being arranged to connect to a common crak-pin. the crank revolving in a horizontal plane. The cylinders are set at angles of 120°, this arrangement giving a steady effort to the crank-shaft and doing away with the necessity of a flywheel. The areas of the passages are so designed as to reduce the friction to a minimum and allow objects usually found in sewage to pass through, without choking the pump. The weight and thrust of the impeller and shaft are taken up by a self-aligning and adjustable thrust-bearing. The engines can be made simple or compound, condensing or non-condensing, as desired, and this company has built pumning units of this type in sizes ranging as high as 165,000,000 gallons per twenty-four hours.
FIREPROOF WAREHOUSES FOR COTTON.
In the Southern States not only are many more substantial cotton warehouses being erected, but concrete is beginning to IKfavored as a building material. At Memphis, Tenn., for example. 106 one-story storage warehouses are being constructed by one company, the outcome of which will be to bring down to the knvest the labor of hauling and handling the cotton, besides considerably reducing the danger of a conflagration. At Macon, Ga., also, a company has just been organised to build twenty or even more warehouses, with a capacity of 1,000 bales of cotton each; and similar reports are being sent in from other quarters. Many of these warehouses are being built of reinforced concrete. In this way, not only will the cotton be stored and moved with less damage to it from a salable standpoint, but the danger of fire will be almost totally taken away. The result will be all in favor_of the cot ton reaching the market in better shape and of the rates of insurance on it being considerably lessened. W. N.