. American engineer and railroad journal . ermethod of construction, for according to the results here givena considerable exchange of heat also takes place in the low-pressure cylinder, in which exteinal radiation may play alarge part. Much, he thinks, still remains to be done withregard to isolating the cylinders by surrounding them withnon-conducting materials. . Careful inquiry has shown that with similar engines afterrunning some years no difficulty has been experienced withthe pistons or valves due to working with highly superheatedsteam. This agrees with the results of experience in Fra
. American engineer and railroad journal . ermethod of construction, for according to the results here givena considerable exchange of heat also takes place in the low-pressure cylinder, in which exteinal radiation may play alarge part. Much, he thinks, still remains to be done withregard to isolating the cylinders by surrounding them withnon-conducting materials. . Careful inquiry has shown that with similar engines afterrunning some years no difficulty has been experienced withthe pistons or valves due to working with highly superheatedsteam. This agrees with the results of experience in France. SOME FACTS RELATING TO CERTAIN TYPESOF WATER TUBE BOILERS.* (Continuedfrom page 104.) UNIT NO. 4. TUBES CLOSED AT BOTH ENDS. There are only two ways by which boilers can be kept effi-cient and economical. The first is to feed them with absolute-ly pure water—practically a physical impossibility. The sec-ond is to arrange them so that the scale due to evaporation canbe removed—that is. provide means which will give free access. Fig. 35 -FIRMENICH BOILER, a Trade Circular Issued at Chicago. to the tubes for cleaning every square inch of their internalsurface. Unit No. 4 starts out all right with straight tubes,but ignores the essential point—facility of cleaning. The Firmenich boiler (fig. 35) consisted of flat-sided hori-zontal drums at top and bottom of a bank of straight tubes. * From advauce sheets of a publication by the Babcock & Wilcox Com-pany. 218 THE AMERICAN ENGINEER [May, Two such units wore placed A fashion, with (lif grates be-tween them at the bottom, and Burmounted with a steam drumon top. These tubes were Inaccessible for cleaning. If the drums were made round and the ends of the tidies
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
