Scientific American Supplement, No. 483, April 4, 1885

Scientific American Supplement, No. 483, April 4, 1885

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Excerpt: ... but at the same time the steam boiler losing steam above, and not being influenced as quickly by the increased heat below, showed a decrease of temperature. The difference of the two temperatures, which was at starting 1.3 deg. Cent., consequently increased to 7.2 deg. Cent, after 17 min., the boiler having then its lowest temperature of 148.8 deg. Cent. After that both temperatures rose together, the difference between them increasing slightly to 9.5 deg. Cent., and then decreasing continually. After 2 hours 13 min., when the engine had made 12,000 revolutions, the soda solution had reached a temperature of 170.3 deg. Cent., which proved to be its boiling point. The steam from the engine was now blown off into the open air during the next 24 min. This lowered the temperature of both water and soda lye by 10 deg. and re-established its absorbing capacity. The steam produced under these circumstances had of course a smaller pressure than before, in this way the engine could be driven at reduced steam pressures until the resistance became relatively too great. The process described above is illustrated by the diagram Fig. 1, which is drawn according to the observations during the experiment. FIG. 1. FIG. 2. The constant rise of both temperatures during the first two hours, which is an undesirable feature of this experiment, was caused by the quantity of soda lye being too great in proportion to that of water, and other experiments have shown that it is also caused by an increased resistance of the engine, and consequent greater consumption of steam. In the latter part of the experiment, where the engine worked with expansion, the rise of the temperature was much less, and by its judicious application, together with a proper proportion between the quantities of the two liquids in the engines, which are now in practical use, the rising of the temperatures has been avoided. The smaller the difference is between the temperatures of the soda lye and more

Product details

  • Paperback | 36 pages
  • 189 x 246 x 2mm | 82g
  • United States
  • English
  • black & white illustrations
  • 1236728033
  • 9781236728036