Page:The New International Encyclopædia 1st ed. v. 07.djvu/698

* FIRE-ENGINE. 636 FIRE-ENGINE. been given to the idea of self-propelled fire-en- gines and other fire-department apparatus, but only a few had been built up to 1901 ; nor can their introduction be rapid until motor vehicles become as reliable as the marvelously trained horses of American fire departments. Hand fire- pumps, drawn by men or horses, were used prior to the advent of the steam-engine, and are still employed in some small towns. They have been brought to a high degree of perfection for a ma- chine of that nature, and are manufactured in a variety of styles and at low prices. The main parts of the steam fire-engine are the boiler, engine, pumps, and the vehicle on which these are mounted. Boilers are generally of the vertical water-tube type. The engines and pumps are also generally vertical, double-acting, and in duplicate. A few makes have both rotary steam and water cylinders, instead of the more common steam-pistons and water-plungers or reciprocat- ing engines. Some light machines have hori- zontal engines and pumps. To facilitate the preparation of fire-engines for service, heaters are maintained in the engine-house to give a constant supply of hot water to the engines. When the alarm strikes the fire is kindled be- neath the boiler, and steam is soon available. The rated capacity of steam fire-engines ranges from about 1300 to 400 gallons per minute, and their weights from 9500 to 5000 pounds. The self-propelled engines already mentioned, as now built, have a capacity of 1350 gallons per minute, and weigh 17.000 pounds when equipped for ser- vice. They are 10 feet high, 16% feet long, and 7i feet wide. The engine is propelled on the road by power from the main crank-shaft, through two chains running over sprocket wheels on the main rear wheels of the engine. The driver steers the engine by means of a hand wheel and rod connected with the front axle through a bevel and worm gearing. By the removal of a key the road-driving mechanism may be discon- nected, whereupon the power becomes available for the pumps. One of these engines, made for the city of Hartford. Conn., when on its first trial is reported to have thrown a stream through 50 feet of 3%-inch hose to a horizontal distance of 348 feet with a 1%-inch nozzle, and 319% feet with a 2-inch nozzle. The first, and for many years probably the only thorough test of -Irani (ire-engines, was that made in 1876 at the Centennial Exhibition at Philadelphia. The results are given in detail in the official report of the exhibition, together with descriptions of the several engines. A more recent series of tests was made at Boston in 1893; both the conditions and the results obtained arc given in detail in thr report of tl ity engineer of Boston for 1893-94. The engines tested were those in regu- lar service by tin' tiro department, some practical- ly new ami others fifteen years old. In all cases the engines drew water from a hydrant under pressures of from 30 to 40 pounds. The largest average quantity of water pumped per minute during the whole of one test was 910 gallons, by B Clapp & Jones engine, the pumps having been run two hours and twenty-three minutes and throwing a total of 130.121 gallons of water. The average steam-pressure was 101.3 pounds, an. I the average water-pressure at the pumps was [12.8 pounds. For shorter periods during (his t> -I better results were obtained; thus, for about twelve minutes there was a discharge of 1022 gallons per minute. It must be understood that various combinations of hose, both as to length and the number of lines, and nozzles of different sizes, were used ; but even with three lines of hose, each 500 feet long, two of which were 2% inches in diameter and had 1%-inch nozzles, while one was 3 inches in diameter and had a Hi-inch nozzle, an average discharge of 900 gallons per minute was maintained for sixty-four minutes, with water-pressure of 53.5 pounds at the nozzles. As stated, the pumps ran two hours and twenty-three minutes altogether, but the engine was under steam for three hours and eight minutes, during which time 2809 pounds of coal were burned and 8398 pounds of water evaporated. This was 2.93 pounds of water per pound of coal, or 3.51 pounds from and at 212° F. The coal used per square foot of grate per hour was 172.1 pounds, and the duty in foot- pounds was 7.758,300 per 100 pounds of coal — i.e. for every 100 pounds of coal burned 7,758,300 pounds of water was raised to an equivalent of 1 foot in height. This engine weighed 7970 pounds, had steam-cylinders 9 inches in diameter, water-cylinders 5% inches in diameter, both of 8-inch stroke. Its boiler was 35% inches in diameter, with a heating surface of 140% square feet. The other engines in this Boston test were all smaller, having steam-cylinders from about 6 to 8% inches in diameter, 4 to 5 inch water-cylinders, but with about the same length of stroke as the more powerful engine. Their calculated capacities ranged from about 500 to 700 gallons per minute, and their average work during the tests was the throwing of 499 to 596 gallons of water per minute. The duties of these engines ranged from 5.882,000 to 14,026,000 foot- pounds per 100 pounds of coal, and the water evaporated from and at 212° F. ranged from 2.26 to 5.87 pounds per pound of coal. The range of duties was about 10 per cent, as great as that of fair to high grade stationary pump- ing engines: but it must be understood that fuel economy is a secondary matter in a fire-engine, the main object being to get the engine to the fire and throw the maximum of water in the minimum of time after the alarm. To enable the engines to be drawn by horses at a high rate of speed, lightness is essential. Fire-engines mounted on fire-boats, like those used by New York, Detroit, and other cities, may be designed with less regard for weight and with more con- sideration for fuel economy; but here, also, quick- ness and effectiveness of service ranks first, so the chief advantage of such fire-engines is that they may be made practically as capacious and powerful as is desired, and may approach tires closely from the water-front side, where the ordi- nary steam the engine cannot be driven. The fire-boat Robert I. Van Wych, for the eu York Fire Department, put. in use in April. 1S9S. has twn sets of pumps, which on test delivered about 3200 gallons of water per minute each, with pump pressures of about 180 pounds. The tire -hnai Deluge, built in 1900 for the city "f Detroit, was designed to have two sets of vertical, triple-expansion pumping engines, with 14 inch steam ami 8 inch water cylinders, all of II inch stroke, ami with a combined capacity of 6000 'gallons per minute. Twn huge nozzles were in eluded, besides 20 connections for 3%-inch hose. Besides steam, gasoline engines an< sometimes used for driving the pumps of portable engines,