Part 26 (1/2)

These were horizontal engines, attached to locomotive boilers.

At a similar exhibition held at Bury, in 1867, considerably better results even than these were reported, as below, from engines of similar size and styles:

KEY: A: Number.

B: Diameter.

C: Stroke.

D: Nominal.

E: Dynamometric.

F: Point of cut off.

G: Revolutions per minute.

H: Pounds coal per horse-power per hour.

---------------+-------------+-----+--------------+------+------+---- MAKERS' NAME | CYLINDERS. | | HORSE-POWER. | | | AND +-----+-------+ +-------+------+ | | RESIDENCE. | A | B | C | D | E | F | G | H ---------------+-----+-------+-----+-------+------+------+------+---- | |Inches.| In. | | | | | Clayton, | | | | | | | | Shuttleworth | 1 |10 | 20 | 10 | 11.00| 3.10 | 71.5 | 4.13 & Co., Lincoln | | | | | | | | | | | | | | | | Reading Iron- | | | | | | | | Works Company, | 1 | 8-5/8 | 20 | 10 | 10.43| 1.4 |109.4 | 4.22 Reading | | | | | | | | ---------------+-----+-------+-----+-------+------+------+------+----

With all these engines steam-jackets were used; the feed-water was highly and uniformly heated by exhaust-steam; the coal was selected, finely broken, and thrown on the fire with the greatest care; the velocity of the engines, the steam-pressure, and the amount of feed-water, were very carefully regulated, and all bearings were run quite loose; the engine-drivers were usually expert ”jockeys.”

The next ill.u.s.tration represents the portable steam-engine as built by one of the oldest and most experienced manufacturers of such engines in the United States.

In the boilers of these engines the heating-surface is given less extent than in the stationary engine-boiler, but much greater than in the locomotive, and varies from 10 to 20 square feet per horse-power.

The boilers are made very strong, to enable them to withstand the strains due to the attached engine, which are estimated as equivalent to from one-tenth to one-fifth that due to the steam-pressure. The boiler is sometimes given even double the strength usual with stationary boilers of similar capacity. The engine is mounted, in this example, directly over the boiler, and all parts are in sight and readily accessible to the engineer.

[Ill.u.s.tration: FIG. 116.--The Portable Steam-Engine, 1878.]

One of these engines, of 20 horse-power, has a steam-cylinder 10 inches in diameter and 18 inches stroke of piston, making 125 revolutions per minute, and has 9 square feet of grate-surface and 288 feet of heating-surface. It weighs about 4-1/2 tons. Steam is carried at 125 pounds.

In the cla.s.s of engines just described, the draught is obtained by the blast of the exhaust-steam which is led into the chimney. Such engines are now sold at from $120 to $150 per horse-power, according to size and quality, the smaller engines costing most. The usual consumption of fuel is from 4 to 6 pounds per hour and per horse-power, burning from 15 to 20 pounds on each square foot of grate, and each pound evaporating about 8 pounds of water. A usual weight is, for the larger sizes, 500 pounds per horse-power.

[Ill.u.s.tration: FIG. 117.--The Thrashers' Road-Engine, 1878.]

These engines are sometimes arranged to propel themselves, as in the Mills ”Thrashers'” road-engine or locomotive, of which the accompanying engraving is a good representation. This engine is proportioned for hauling a tank containing 10 barrels, or more, of water and a grain-separator over all ordinary roads, and to drive a thras.h.i.+ng-machine or saw-mill, developing 20 or 25 horse-power. This example of the road-engine has a boiler built to work at 250 pounds of steam; the engine is designed for a maximum power of 30 horses.

This engine has a balanced valve and automatic cut-off, and is fitted with a reversing-gear for use on the road. The driving-wheels are of wrought-iron, 56 inches diameter and 8 inches wide, with cast-iron driving-arms. Both wheels are drivers on curves as well as on straight lines. The engine is guided and fired by one man, and the total weight is so small that it will pa.s.s safely over any good country bridge. A brake is attached, to insure safety when going down-hill. Although designed to move at a speed of about three miles per hour, the velocity of the piston may be increased so that four miles per hour may be accomplished when necessary.

[Ill.u.s.tration: FIG. 118.--Fisher's Steam-Carriage.]

This is an excellent example of this kind of engine as constructed at the present time. The strongly-built boiler, with its heater, the jacketed cylinder, and light, strong frame of the engine, the steel running-gear, the carefully-covered surfaces of cylinder and boiler, and excellent proportions of details, are ill.u.s.trations of good modern engineering, and are in curious contrast with the first of the cla.s.s, built a century earlier by Smeaton.

Steam-carriages for pa.s.sengers are now rarely built. Fig. 118 represents that designed by Fisher about 1870 or earlier. It was only worked experimentally.

[Ill.u.s.tration: FIG. 119.--Road and Farm Locomotive.]

The above is an engraving of a road and farm locomotive as built by one of the most successful among several British firms engaged in this work.

The capacity of these engines has been determined by experiment by the author in the United States, and abroad by several distinguished engineers.

The author made a trial of one of these engines at South Orange, N.

J., to determine its power, speed, and convenience of working and man[oe]uvring. The following were the princ.i.p.al dimensions:

Weight of engine, complete, 5 tons 4 cwt. 11,648 pounds.

Steam-cylinder--diameter 7-3/4 inches.