. Railway mechanical engineer . 4-in. standard nozzle with-out a bridge, are shown in the first line of the table forcomparison with the other combinations of annular nozzlesand stacks. The results of runs No. 21-22 are again shownto afford further comparisons. During run No. 23, a stack was used with the same inside extension andsize of nozzle as used in runs No. 26-27-28, where a straight stack was employed. \Aith the standardtaper stack the draft obtained was slightly improved, while. /lrea44 ZS (/Ipprox Sijuiv io 7? Dom Circ/ei I Fig. 12—Annular Nozzle A-4 the
. Railway mechanical engineer . 4-in. standard nozzle with-out a bridge, are shown in the first line of the table forcomparison with the other combinations of annular nozzlesand stacks. The results of runs No. 21-22 are again shownto afford further comparisons. During run No. 23, a stack was used with the same inside extension andsize of nozzle as used in runs No. 26-27-28, where a straight stack was employed. \Aith the standardtaper stack the draft obtained was slightly improved, while. /lrea44 ZS (/Ipprox Sijuiv io 7? Dom Circ/ei I Fig. 12—Annular Nozzle A-4 the draft efficiency under each condition was identical,which leads to the conclusion that no advantage was gainedby using the straight stack. The exhaust stack diagramsfor these two sets of runs is shown in Fig. 7. The satisfactory results from nozzle style A-1 encour-aged further investigation along this line, and nozzle st;,l3A-2 was developed. This is illustrated in Fig. 8. It shouldbe noted that the center opening shown in this drawing isprovided to accommodate a central blower pipe and is nota nozzle port. The theory followed in designing these nozzles on a largerexternal circle with the exhaust opening divided into an-nular ports, was to afford greater opportunity for the en-trainment of the combustion gases by increasing the ex-ternal surface of the exhaust column which is exposed forcontact with the gases. Hence, in the design of nozzle styleA-2 it was constructed on a 14-in. external circle, which is
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
