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A History of the Growth of the Steam-Engine

He adopted greatly increased piston speed


In

the same year, Perkins made a compound engine on the Woolf plan, and adopted a pressure of 1,400 pounds, expanding eight times. In still another engine, intended for a steam-vessel, Perkins adopted, or proposed to adopt, 2,000 pounds pressure, cutting off the admission at one-sixteenth, in single-acting engines of 6 inches diameter of cylinder and 20 inches stroke of piston. The steam did not retain boiler-pressure at the cylinder, and this engine was only rated at 30 horse-power.[90]

[90] Galloway and Hebert, on the Steam-Engine. London, 1836.

Stuart follows a description of Perkins's work in the improvement of the steam-engine and the introduction of steam-artillery by the remark:

" ... No other mechanic of the day has done more to illustrate an obscure branch of philosophy by a series of difficult, dangerous, and expensive experiments; no one's labors have been more deserving of cheering encouragement, and no one has received less. Even in their present state, his experiments are opening new fields for philosophical research, and his mechanism bids fair to introduce a new style into the proportions, construction, and form, of steam-machinery."

Perkins's experience was no exception to the general rule, which denies to nearly all inventors a fair return for the benefits which they confer upon mankind.

Another

engineer, a few years later, was also successful in controlling and working steam under much higher pressures than are even now in use. This was Dr. Ernst Alban, a distinguished German engine-builder, of Plau, Mecklenburg, and an admirer of Oliver Evans, in whose path he, a generation later, advanced far beyond that great pioneer. Writing in 1843, he describes a system of engine and boiler construction, with which he used steam under pressures about equal to those experimentally worked by Jacob Perkins, Evans's American successor. Alban's treatise was translated and printed in Great Britain,[91] four years later.

[91] "The High-Pressure Steam-Engine," etc. By Dr. Ernst Alban. Translated by William Pole, F. R. A. S. London, 1847.

Alban, on one occasion, used steam of 1,000 pounds pressure. His boilers were similar in general form to the boiler patented by Stevens in 1805, but the tubes were horizontal instead of vertical. He evaporated from 8 to 10 pounds of water into steam of 600 to 800 pounds pressure with each pound of coal. He states that the difficulty met by Perkins--the decomposition of lubricants in the steam-cylinder--did not present itself in his experiments, even when working steam at a pressure of 600 pounds on the square inch, and he found that less lubrication was needed at such high pressures than in ordinary practice. Alban expanded his steam about as much as Evans, in his usual practice, carrying a pressure of 150 pounds, and cutting off at one-third; he adopted greatly increased piston-speed, attaining 300 feet per minute, at a time when common practice had only reached 200 feet. He usually built an oscillating engine, and rarely attached a condenser. The valve was the locomotive-slide.[92] The stroke was made short to secure strength, compactness, cheapness, and high speed of rotation; but Alban does not seem to have understood the principles controlling the form and proportions of the expansive engine, or the necessity of adopting considerable expansion in order to secure economy in working steam of great tension, and therefore was, apparently, not aware of the advantages of a long stroke in reducing losses by "dead-space," in reducing risk of annoyance by hot journals, or in enabling high piston-speeds to be adopted. He seems never to have attained a sufficiently high speed of piston to become aware that the oscillating cylinder cannot be used at speeds perfectly practicable with the fixed cylinder.


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