The Indicator Diagram Practically Considered

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. 1881 Excerpt: ... direction of the arrow, and the piston has advanced in a relative distance, while the slide-valve has closed the steam-port, and has a retrograde motion to that in Fig. 2. Notice also that the space tilled in in the diagram Fig. 5 is the same distance the crank-pin has travelled on the plane line; the dotted curve line in each case shows the relative position of the piston. When the crank arrived at B, the steam was cut off by the slidevalve and expansion commenced, and the nonescape from the cylinder was continued until the valve and crank were in the positions, as shown by Fig. 6. Turning again to Fig 2, it will be apparent, on comparing it with Fig. 6, what distance the G piston has travelled before the steam is dispensed with or exhaustion commences, also the portion of the circle described by the crankpin during the same time. Fig. 7 represents the amount of pressure in the cylinder at the moment the exhaustion occurs; it explains, also, the decrease of pressure from the point of cut-off to the release. The relative diagram areas of supply and expansion are manifest, and the length on the atmospheric line agrees with the plane travel of the crank-pin. Now the time allowed for exhaustion is due to the travel of the slide-valve, less the inside laps, and while the valve is performing this the piston also completes its stroke and has a return motion. The Fig. 8 will assist now. Here the valve has just closed the supply-ports, terminated exhaustion, and the crank-pin has travelled from 0 in Fig. 6 to D in Fig. 8, where the relative positions of the pistons are also shown, Fig. 9 shows the amount of vacuum attained, and that when the crank left C in Fig. 7 the pressure in the cylinder gradually fell to that ot the atmosphere before the stroke of the piston...