. The street railway review . ons may be,it should be so arranged that the elasticity of the pipe will be suf-ficient to take care of expansion and contraction. This is the onlymeans acknowledged as being permanent and efficient. There arevarious special devices for caring for expansion, but their use isconfined to emergency cases only, or cases which will not permit theuse of sufficient length of pipe to secure the desired flexibility. Supports for steam mains should be laid out to allow for bothexpansion and the side movement of the line, as illustrated in detailAi-s, Fig. 71. The points m t
. The street railway review . ons may be,it should be so arranged that the elasticity of the pipe will be suf-ficient to take care of expansion and contraction. This is the onlymeans acknowledged as being permanent and efficient. There arevarious special devices for caring for expansion, but their use isconfined to emergency cases only, or cases which will not permit theuse of sufficient length of pipe to secure the desired flexibility. Supports for steam mains should be laid out to allow for bothexpansion and the side movement of the line, as illustrated in detailAi-s, Fig. 71. The points m the pipe line that would be the centerof the expansive forces should be anchored to avoid vibration ofthe lines. Expansion and vibration are two conditions that must beprovided for and neither must be permitted to interfere with theother. This subject will be more fully considered under PipingSupports. The fittings ordinarily used for large steam pipes are made ofcast iron and are extremely heavy. A much more desirable fitting. FIG. 72—(ai-6). could be made of soft steel plate, stamped and lap-welded, asshown in detail A1-7, Fig. 73 The flanges could be of rolled steel, making an all-steel fitting,light and somewhat elastic. If the manufacturer had his factoryequipped with proper machinery for making such a line of fittings,he could without doubt produce them for about same shop cost ascast-iron fittings. There is no question but that the engineers wouldbe universally in favor of using the steel plate fitting, and even iftheir cost was 50 per cent more, large sized fittings would in-variably be specified of this make. A demonstration of the general NiiV. 15, 1905.] STRI RAILWAY Ki-:vii:w 817 desire for something more reliable tliaii cast iron is evidenced bythe very extensive, and in fact, ahnost universal use of rolled-steelflanges in place of cast-iron ones, which were formerly used forhigh grade, high pressure work. Manufacturers are using whatthey term semi steel for high
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Keywords: ., book, bookcentury1800, bookdecade1890, booksubjectstreetrailroads
