Power Volume 55, No. 7 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 Excerpt: ... engine, with throttling governor, show considerable falling off of the pressure during admission. Could not the engine develop more power if fitted with a shaft governor? W. A. C. The falling away of admission pressure when the engine is loaded, to obtain the lowest running position of the present throttling governor, may be due to contracted steam ports and passages, and there would be the same defect of diagrams made with a shaft governor and balanced valve. The cutoff could not occur so late in the stroke, and although there might be better speed regulation and higher pressure during admission, less power could be developed than from the later cutoff with the throttling governor. Setting Eccentric for Indirect Valve How would the eccentric of an engine be set for an indirect piston valve that is coupled to the eccentric rod with a direct rocker? R. G. A piston valve is like a flat slide valve would be if rolled up in the form of a cylinder with a bored cylindrical seat in place of a flat seat. When, as with the ordinary D slide valve, steam is admitted at the ends of the valve, the steam port is uncovered at the beginning of the stroke of the piston by moving the valve in the same direction as the piston, and with a direct rocker the eccentric must be set 90 deg. plus the angle of advance ahead of the crank. But when the openingedge of the valve uncovers the steam admission port by movement of the valve in a direction opposite to the direction of movement of the piston as would be necessary for admission of steam in the middle of the valve and discharging the steam at the ends, the valve would be called indirect, and to effect the indirect motion with a direct rocker, the eccentric would have to be set 90 deg. behind the crank, less the necessary number...