. American engineer and railroad journal . the old fire box, so that for a crown sheet of the same sizethe proportional gain in heating surface is even greater thanthat indicated by the above figures. It is true that in boilers with radially stayed crown sheets,the stays do not offer the same amount of obstruction as thecrown bars. Nevertheless, several rows of radial stays areusually replaced by three or four rows of sling stays at theforward end of the crown sheet. T-irons of these sling staysimpede circulation as much as the ordinary crown bar andproduce the same effect upon the accumulatio
. American engineer and railroad journal . the old fire box, so that for a crown sheet of the same sizethe proportional gain in heating surface is even greater thanthat indicated by the above figures. It is true that in boilers with radially stayed crown sheets,the stays do not offer the same amount of obstruction as thecrown bars. Nevertheless, several rows of radial stays areusually replaced by three or four rows of sling stays at theforward end of the crown sheet. T-irons of these sling staysimpede circulation as much as the ordinary crown bar andproduce the same effect upon the accumulation of mud andscale. This formation is at the point of the crown sheet wherethe greatest difficulty from cracking occurs and is, therefore,the point wdiere there should be the least accumulation of mud. While the straight radial stay does not cause the same accumu-lation as the crown bar or the T-iron, the large number of staysoffers much more impediment than the few thin stays of theJacobs-Shupert construction and consumes more space which. FIREBOX OF CROWN BAR BOILER SHOWING ACCUMULATION OF SCALE AND SEDIMENT.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
