. American engineer and railroad journal . reat measure, thetemperature of the water and steam contained in the boilerwith mi apparent, though with an undeniable economy. Thephenomenon may !»• explained as follows: When the waterenters the heating tubes it travels without boiling through acertain length of those tubes ; the lower its temperature isbelow that of the steam, the longer this distance ; and, sincethe circulation is caused by the development of bubbles in thetubes, the intensity of the circulation is reduced as this differ-ence of temperature increases. For the last two years 1 have
. American engineer and railroad journal . reat measure, thetemperature of the water and steam contained in the boilerwith mi apparent, though with an undeniable economy. Thephenomenon may !»• explained as follows: When the waterenters the heating tubes it travels without boiling through acertain length of those tubes ; the lower its temperature isbelow that of the steam, the longer this distance ; and, sincethe circulation is caused by the development of bubbles in thetubes, the intensity of the circulation is reduced as this differ-ence of temperature increases. For the last two years 1 have obtained the same result in themost simple manner by introducing the feed in the steamspace under the form .if spray, as far as possible from thatpart where the steam is taken for the engines. The feedbeing already heated by steam having done work in the high-pressure and medium-pressure cylinders, there is scarcely anydifference of temperature between the water and the steam inthe boiler. As soon as the water enters the heating lubes. Fig. of steam are produced, and the circulation is increasedto such a rate that tlie temperature of the tube is not higherthan with cold feed. This mode of introducing the feed,which has the further advantage of depositing the calcareoussalts in the form of powder, when using sea water, requiressome very simple but in order toavcid shocks in the feed-pipes. The temperature of the products of combustion would beenormous and greatly superior to that at which the dissociation of carbonic aciil and steam takes place, if it could becompleted in the tire box. Starting from Ibis undeniable fact,some engineers think that the heat should be progressivelysubtracted by cool surfaces during the combustion of the coalThis is certainly not the case. No cooling should take placeduring the combustion of , which cannot give itstotal heat unless it takes place in a white-hot refractory re-ceiver, where it is impossib
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
