. The Street railway journal . DETAIL OF NEW HEATER ing from the fact that they are to be wired in accordance withthe new rules of the National Board of Fire Underwriters, pub-lished in the Street Railway Journal for July 16. Theserules, it will be remembered, provide that the heaters shall beso constructed that the current shall be carried at least 4 the woodwork, and that the circuits are to be run in ap-proved metal conduits. Each car is to have sixteen heaters, and the connecting wires The application of fans to induced draft work has madenecessary many changes from the establishe
. The Street railway journal . DETAIL OF NEW HEATER ing from the fact that they are to be wired in accordance withthe new rules of the National Board of Fire Underwriters, pub-lished in the Street Railway Journal for July 16. Theserules, it will be remembered, provide that the heaters shall beso constructed that the current shall be carried at least 4 the woodwork, and that the circuits are to be run in ap-proved metal conduits. Each car is to have sixteen heaters, and the connecting wires The application of fans to induced draft work has madenecessary many changes from the established standards of fanbuilders to avoid difficulties never met with in other lines offan work, and even hardly anticipated in this. Most of the fanson the market to-day are built with two or three spiders, exceptin the very small sizes. A fan of the standard type usually hasa bearing on each side of the fan. making the distance betweenbearings comparatively short. With this arrangement there is. FIG. 1—WHEEL FOR MECHANICAL DRAFT APPARATUS, WITHSPIDER BUILT UP OF I-BEAMS no deflection to the shaft, and the fan wheel is very smoothrunning. But when these fans have to be adapted to the hand-ling of hot gases, it is positively necessary to keep the bearingsremoved from the path in which the gases travel, as the bear-ing would become overheated. This necessitates either havingan overhung wheel or placing one bearing outside of the inletchamber built onto the side of the fan. Unless the bearingswere placed very close to the center of the fan, the overhangwill cause deflection, which will work the keys loose and morelikely cause the fan wheel to strike the housing. The same isin a large measure true of the two bearings far apart. Increas-ing the diameter of the shaft is not a relief, as by its own weight prTrnnnpaTinnnrrtinnnnnnnnnnnDnnnDnDnDnnnncpDnnnDDnGLinnDocnnnnnnnnnnonnnnnnnDnDnnDp, % -jOr^^ CO»SOLlDAT|DCABN HEAT1NaCO. „TWTS0. ^ aj nDnnonnDnonnHnncnDnnnnnnnnDcnnDDnonngDDn
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
