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XIV. Melling's Improvements in Locomotive Engines.
pressing Peat; Douglas's Machinery for Obtaining
table Charcoal. XVI. Ledsam and Jones's Machinery for Making Pins and
Needles ; Brunton's Excavating Machinery; Smith's
and Kinder's Machinery for Dressing Cloth. XVII. Leggett's Machinery for Printing in Colors, and Reid
and Paterson's Improvements in Looms. XVIII. Sharp's Improvements in Dressing Flax ; Walton's Im
proved Wire Cards; and Millichap's Locomotive
Carriage. XIX. Palmer's Improvements in Propelling Vessels, and Red
mund's Improvement in Locomotive Steam Engines.
JOURNAL AND REPERTORY
Arts, Sciences, and Manufactures.
To Joseph MAUDSLAY and Joshua Field, of Lambeth,
in the county of Surry, engineers, for their improvements in the construction of marine steam-engines, which are particularly applicable to steam-engines of the largest class.-[Sealed 7th May, 1839.]
These improvements in the construction of marine steamengines are particularly applicable to those of the larger class, and are designed principally for the purpose of producing and applying a greater amount of steam power than has heretofore been available within a given space or area on shipboard. This is effected by different constructions, arrangements, and proportions of the parts of low pressure engines, allowing a more perfect application of the expansive force of steam without increasing the weight of the whole machinery.
The first feature of these improvements consists in adapting two steam cylinders to one engine, in such a way, that the steam shall act simultaneously upon both pistons, in order that they may be made to rise or fall together, the piston rod of each being attached to one horizontal crosshead, and thereby the combined action of both pistons applied to one crank of the paddle shaft.
The second feature of these improvements applies more particularly to engines for river navigation, and consists in the adaptation of a piston with two rods, working in a steam cylinder of large area, both piston rods being connected to one cross-head above, which gives motion to the crank below it, by a single connecting rod.
The third feature of these improvements consists of a method of adjusting the expansion valves of combined engines, by which the period for shutting off the steam, at any part of the stroke, may be regulated in both engines at once by a single movement, whilst the engines are working.
The fourth feature of these improvements is the peculiar construction of the main beams of the framing that carry the plummer blocks of the main crank shaft to which the paddle wheels are attached. These beams are formed as hollow trunks, by the combination of wrought-iron plates, attached to bars of angle iron, in the same way as ordinary boilers are made; and by that means beams may be constructed of the largest dimensions, of unlimited strength, and of comparatively small weight.
These improvements will be more fully understood by reference to the accompanying drawings, and the following description thereof, see Plate I., in which fig. 1, is an elevation, taken longitudinally, representing an engine with two cylinders, constructed upon the plan described as the first feature of these improvements; fig. 2, is a vertical
section of the same, taken through the cylinders ; fig. 3, is a horizontal view of a pair of engines, in which the situation of the engine, shewn at fig. 1, is seen, as it would appear when looking upon it from above ; fig. 4, is a corresponding engine, placed at the other side of the vessel, but
represented in section, cut horizontally through the cylinders ; fig. 5, is a vertical section, taken transversely through a steam vessel, shewing the positions of two engines, as in figs. 3 and 4, the one engine being in section, the other an external view, seen upon a plane in advance of the former; and fig. 6, is a plan or horizontal view of a portion of the steam vessel, with the engines and their appendages; and also the framing, by which the crank shafts of the paddle wheels are supported, similar letters referring to the same parts of the machinery in all the preceding figures.
The two connected working cylinders are shewn at a, a; their pistons at b, b; and the piston rods at c, C,—the upper ends of which rods are affixed by keys to the crosshead d. Four vertical rods e, e, e, e, affixed at top to the cross-head d, are connected at bottom to a slider f, which slider is enabled to move up and down on the guide ribs g, g, formed on the outer surfaces of the cylinders. — To this slider f, one end of a connecting rod h, is attached, the other end of that rod being attached to the crank i, of the propelling shaft.
From this arrangement it will be perceived, that by the simultaneous ascent and descent of the two pistons b, b, in their working cylinder a, a, the rods c, c, will cause the cross-head d, to move perpendicularly up and down between its guide bars j, j, and in so doing to raise and depress the slide f, with the connecting rod h, which rod will, by that means, be made to give rotary motion to the crank i, and thereby cause the paddle wheel shaft k, to revolve. A rod 1, connected to the slide f, will, at the same time, work
the lever m, to which the rod of the air-pump n, is attached.
The mode of adapting the steam valve of the combined cylinders a, a, is best seen in figs. 3 and 4. The steam is admitted to and withdrawn from these cylinders by one slide valve common to both, through a pipe n, seen in fig. 5. From this pipe n, the steam proceeds through a slide valve o, of the ordinary construction, and through the curved passages or tubes p, p, into both cylinders. There is also a narrow passage of communication always open by which the steam is allowed to pass from one cylinder to the other for the purpose of keeping the pressure equal at all times in both cylinders.
The expansion valve is on the steam pipe n, at the entrance to the slide valve; the slide is moved by an excentric in the ordinary way, and the expansion valve is regulated by the means described hereafter, under the third feature of our invention.
The advantages proposed by this arrangement, are simplicity of construction, more direct action on the crank, saving of space and weight of material, offering easy means of giving larger area of cylinder, whereby a given amount of steam can be used more expansively than in former arrangements, and consequently yield more power and economise fuel,—with the further advantage at sea, that when the engine is reduced in the number of its strokes by deep lading of coal, as at the commencement of a voyage, or by head winds, more steam may then be given to the cylinders, and, under such circumstances, inore speed to the vessel,--all the steam generated in the boiler being usefully applied.
The second feature of our invention, viz. the improved construction of steam-engines, having two piston rods working in one cylinder, is represented at Plate II., in