The annexed diagram is explanatory of a holler which has been em ployed for the gene ration of steam in the locomotive carriage of Messrs. Summers and Ogle, who have taken out a patent for it. I t consists of a series of tubes, placed vertically, with a flue passing up the centre of each; a as represents extcriud tubes cent ining the v.ater and steam ; bbbtbe interior tubes or flues, for the passage of a portion of the heated air, &c., the remainder passing off between the exterior tubes ; and thus the water of the boiler disposed in thin hollow cylinders is continually exposed to an extensive surface of heated metal on both sides. c c c are the ends of the internal tubes passing through the screwed nuts d d d at the top, and e e e at the bottom, and by which both the exterior and interior tubes are secured in their places. The water is supplied to the boiler through the pipe f, by a force pump; and the steam when generated, passes off to the engine, by the pipe i. Although the heated matters from the fire have but a short passage to the chimney, it is obvious that the obstruction to the current formed by so many tubes crowded together must be considerable, and cause a great portion of the heat to be absorbed, it being, as it were, wire-drawn. Economy of fuel is, however, not a matter of such important consideration in a steam carriage, as in fixed engines; there being in the present infant state of locomotion, on the common road, no competition. It is obvious that the different parts of this boiler can be put together with facility, and that a defective tube can be instantly removed, and a sound one substituted, by simply unscrewing the interior flue or tube. The manufacture, however, requires the utmost exactness, especially in making all the tubes of precisely the same length, and the othercorresponding with each other of uniform dimensions; otherwise a source would arise, from the longer tubes preventing the shorter ones from being screwed sufficiently close to render them steam-tight.
Although the inventions of Mr. Jacob Perkins (who has distinguished himself by numerous ingenious attempts to generate and work steam at pressures far beyond that of any other experimentalist or engineer,) have not been attended with that success which the public were led to believe, many of his arrange ments possess considerable merit, and ought to have a place in this work. We allude in particular to his having brought steam of enormous pressure under the most perfect control. The annexed diagram is explanatory of a boiler employed by Mr. Perkins, which we saw working a small engine on the high pressure and expansion principle, calculated by him at 30 horses' power. A series of cast-iron bars, 5 inches square, perforated throughout longitudinally, with 11 inch circular holes, were arranged in three tiers, A, B, and D, across a furnace, of sufficient length to come through the opposite walls, where their extremities were connected together in a peculiar manner, so as to form one continuous vessel. By the operation of a forcing pump water was continually injected under the pressure of a heavily loaded valve into the two upper tiers of tubes, so as to keep them always full ; the third or lowest tier of tubes con tained no water, and were to be kept at a temperature of about 1000° Fahrenheit.
At each stroke of the engine, a certain quantity of the water contained in the two upper tiers, (supposed to have acquired a temperature of 7000 or 80000 was discharged into a valve box at C, communicating with the lowest tier of tubes D, wherein it flashed into steam, and passing successively through those tubes, exposed to the intensity of the fire, it was received into a steam chamber L for the supply of the engine. The object of the inventor in introducing such great masses of metal into his apparatus is not very apparent, unless it be the pre vention of sudden and great variations of temperature in the tubes, which perhaps could not otherwise be effected, as the body of water they contain is too small to maintain much uniformity of heat, and Mr. Perkins must be well aware that the perfect safety of such generators is not increased by form ing them of a square figure instead of circular.
To obviate the destructive effects of the direct action of the fire upon the substance of which a boiler is constructed, and by which action the liability to rupture is increased, a great variety of plans have been projected. Three of these plans, which appear tole deserving the attention of the reader, we shall subjoin.
The first is the invention of Mr. Aaron Manby, of Horsely, near Tipton, in StaiRkdshire, for which he had a patent in the year 1821. It is well known that oil and other fatty matters are capable of being raised in temperature far above that of boiling water, without undergoing decomposition; this property in oil having never before been applied to the working of a steam engine, formed the groundwork of Mr. Manby 's patent. The construction of his apparatus is explained by the annexed diagram ; where a represents an oblong boiler, sup posed to be set in brickwork, over a fire-place of the usual construction. This vessel is to contain the oil, which is to be heated to about 300° Fahrenheit. The vessel above b is a strong cylinder, containing the water to be converted into steam, inside of which is fixed a system of pipes, connected into one continuous line ; through these pipes the oil is made to flow by the action of a pump at c, (worked by the engine, or other first mover,) which raises it by the pipe d, and discharges again into the boiler by the pipe e. The heated oil in its pas sage through the pipes elevates the temperature of the surrounding water, and converts it into steam of several atmospheres' pressure. The patentee states, that by this apparatus steam of very high pressure may be generated without the possibility of danger, and that a smaller quantity of fuel is consumed than when the fire operates in immediate contact with the water vessel. In what manner, however, this economy is effected is not very apparent; and although the danger of explosion in the steam vessel is considerably lessened, the liability to accidental conflagration is so far increased by the contiguity of the furnace to such an inflammable substance as oil, (which was liable also to become thick and glutinous) as to render it imprudent to use the apparatus in buildings that are not fire-proof.