Modern American Railway Practice

Modern American Railway Practice

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1908 edition. Excerpt: ... will be explained further on, and are eight in number, instead of six as in the other pumps. (See Plate 86, Fig. 6.) The reason the intermediate valves are so called is because of the fact that the low pressure cylinder discharges its air into the high pressure cylinder through these valves, and they are therefore intermediate be'tween the low and high pressure air cylinders. The action of the air valves in the No. I and No. 2 pump is as follows: As the low pressure piston starts on its upward stroke a partial vacuum is created on the under side of it and atmospheric pressure forces the bottom receiving valve up (this valve is marked 9) arid allows the low pressure cylinder to receive a charge of atmospheric pressure, and as this piston does not move again until the piston in the high pressure cylinder makes its stroke, you will at once see that when the piston of the high pressure cylinder moves up, and creates a partial vacuum, the bottom receiving valve and also the bottom intermediate valve (marked No. 11) are both forced off their seats by atmospheric pressure rushing into the high pressure cylinder, and when the atmosphere has equalized in both cylinders then both valves drop to their seats. As the low pressure piston starts down, as shown in Fig. 4 on Plate 84, the lower intermediate valve (11) is forced from its seat so that the compressed air in cylinder D passes into cylinder C, which was previously charged with atmospheric pressure, so that the cylinder C now contains three measures of air, for the reason that cylinder D is twice the size of the high pressure cylinder C. PLATE 84--FIG. 4. NEW YORK DUPLEX PUMP, DOWN-STROKE. LOW PRESSURE PISTON. VVhile the low pressure piston is moving down the top receiving valve (9) more

Product details

  • Paperback | 104 pages
  • 189 x 246 x 6mm | 200g
  • United States
  • English
  • black & white illustrations
  • 1236833538
  • 9781236833532