. The railroad and engineering journal . of the other designs. Access is had tothe valves by covers placed on top of the steam-chest. Asmentioned before, there are six journals in the bed-plate,all of equal length, and all things being equal, shouldwear down alike. The crank is in three duplicate inter-changeable parts, therefore making a very simple crankto build and repair. With this same arrangement of jour-nals and crank-shafts the valve gear is brought in linewith the valves without any off-sets or bent eccentricrods. What would have been a very pleasing design tothe eye many times has be
. The railroad and engineering journal . of the other designs. Access is had tothe valves by covers placed on top of the steam-chest. Asmentioned before, there are six journals in the bed-plate,all of equal length, and all things being equal, shouldwear down alike. The crank is in three duplicate inter-changeable parts, therefore making a very simple crankto build and repair. With this same arrangement of jour-nals and crank-shafts the valve gear is brought in linewith the valves without any off-sets or bent eccentricrods. What would have been a very pleasing design tothe eye many times has been marred by a bent eccentricrod, aside from the mischievous way they have of dodgingtheir work. There is another design of triple-expansion engine thatis considered the simplest and cheapest to build, but doesnot seem to take as well—that is, those that have twocylinders in line fore and aft, the intermediate and low-pressure, with the high-pressure placed on top of the inter-mediate cylinder (fig. 4). The principal objection to this. plan is that it throws too much work on one crank-pin,making a very unequal strain on the crank-shaft, and, youmay say, all of the other working parts of the has been to the writers knowledge but one enginebuilt on this plan for the lake service. Although it workedwell and gave every satisfaction, it did not seem to attractthe attention that the others did built on the three-cylinder,fore-and-aft plan. Since the triple-expansion engine came out it has beenthe aim of designers to so proportion the cylinders thatthe work done in one will be about equal in each, thusequalizing the fall of temperature. In some cases developed would not vary more than 3 to 5 in eachcylinder, but this equalizing of power has been assistedby the sliding blocks in the reverse arm lengtheningout or shortening the valve travel. It would seem thebetter way to so proportion the cylinder valves and size ofreceiver space that the work done in each cylind
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Keywords: ., bookcentury1800, bookdecade1880, bookidrailroadengi, bookyear1887
