Rensselaer Union, Volume 11, Number 15, Rensselaer, Jasper County, 26 December 1878 — Locomotives Without Fire. [ARTICLE]

Locomotives Without Fire.

Machines on the above-named principle are now at. work on the tramway from Rueil to Marly, near Paris, and with very satisfactory results. The system in use is one introduced by M Francy, an engineer, and is based on the fact that water boils at a lower temperature proportionately to the reduction of the atmospheric pressure. Most of our readers are aware that although water requires a heat of 212, deg. Fah. to boil at the level of the sea, a much lower temperature is sufficient to produce ’tile same effect on the top of a mountain. We will now explain how that physiological fact is practically employed. Into a reservoir of thin steel—we cannot call it a boiler, for it has neither fireplace nor fire, is introduced 1,800 liters of water at a temperature of 200 deg. Fah., and then covered up hermetically. The steam it gives off at once fills the superincumbent space, and produces a pressure of fifteen atmospheres. As soon as any of the vapor is turned on for moving the machine the pressure is reduced, and the water then begins to boil, producing a fresh supply of steam. Of course, that process is of but limited extent, as, at the commencement, the liquid only contained a certain amount of heat, which is gradually diminished as the reproduction of steam takes place at lower temperature by the exhaustion of the superincumbent pressure. So far a machine of this description would be obviously totally inadequate to any very prolonged journey. But for short transits it has been found extremely serviceable. As the amount of pressure required to work the engine is only five atmospheres, a series of valves are so arranged as to prevent a greater ataount of force issuing from the reservoir than is necessary, and thus retaining as far as possible the heat originally contained in the water. The driving part of the machinery is nearly identical with that of ordinary locomotives, with a few modifications, with the purpose of guarding against the useless waste, of the heat originally introduced into the reservoir.—Galignani's Messenger. Punctuality begets confidence, and is the sure path to topor and respect.