Steam-whis′tle.
A sounding device connected with the boiler of a steamengine, either stationary, locomotive, or marine, for the purpose of announcing the hours of work, signaling, etc.
It was invented about 1826 by
Adrian Stephens, chief mechanic at Plymouth Works,
England, and afterward of Merthyr Tydvil,
Wales, and was designed to render clearly audible the escape of steam from the safety-valve.
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Steam-pressure water-elevator. |
Fig. 5738 illustrates the whistle of a locomotive-engine.
The foot is bolted on to the fire-box, has an opening for the admission of steam, and is provided with a cock, by turning which steam is permitted to rush into the hollow piece, which is provided with holes around its lower and narrower portion, through which the steam rushes into the cavity of the cup, and, passing out through the narrow annular opening, impinges against the rim of the bell, causing a shrill, piercing sound.
Holes in the top of the hell permit the escape of the steam upwardly and increase the volume of sound.
The quality of the tone depends on the width of the annular opening, the depth of the bell, and the distance between it and the cup.
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Steam-whistle. |
The Calliope (which see) is a series of such whistles tuned to a scale and operated by keys.
See Patent 13,668 of 1855.
Steam-whistles are also made to give varying tones by graduating the length of the pipe or cup.
Patent 131, 176 of 1872 has in the bell a removable piston which graduates the sound so as to play a tune.
Patent 142, 166 of 1873 has a bell which consists of a fixed open cylinder and a slightly larger cylinder closed at one end and sliding over the first.
This makes a telescopic sounding-tube, the length of which may be varied to produce musical notes.
Patent 141, 280 of 1873 has a series of gates in the body of the pipe, which form
tampons to vary its length, and so form musical notes.
No 29,915 of 1860 has a series of reeds in a chamber and movable shutters for closing all but the one required to sound a given note.
