How to Run Engines and Boilers, with a New Section on Water-Tube Boilers; Practical Instruction for Young Engineers and Steam Users

How to Run Engines and Boilers, with a New Section on Water-Tube Boilers; Practical Instruction for Young Engineers and Steam Users

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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. 1899 edition. Excerpt: ...is used the dotted lines show the position of the eccentrics. Setting the cut-off valves of an engine is a very short job. Usually these valves are so fitted that they operate from no admission at all--zero, so called--to full stroke. Sometimes, however, they are not connected to the governor, but are set to cut off at some fixed point, say one-half of the stroke. To do this, or to cut off at any point of the stroke, it is only necessary to square the valves in theii travel over the main valve, run the crosshead to the point at which it is desired to cat off the steam, set the valves so that they just close the main steam valve port, and then turn the eccentric around on the shaft until it will connect with the cut-off valve gear. Or, connect the cut-off valve gear with the eccentric and then turn the same on the shaft until it just closes the ports at the desired point. CHAPTER XII. Return Crank Motion. The return crank motion is the same as an eccentric, and is set in the same way. It has, however, the disadvantage that the lead can not be changed unless there is a slot for the pin a to move in; for, as will be seen in fig. 18, moving the return crank in or out from the center of the main shaft merely increases the travel of the valve, the lead being very slightly affected. It must be borne in mind that setting the eccentrics of an engine is at best a haphazard operation when it is done while the engine is cold. Many changes take place in the valves and valve motion when the engine has been run a while and after it has been heated up. Cast-iron expands materially by heat, and the valve gearing itself stretches, if we may so term it. That is to say, the strain imposed upon the several joints and connections make the actual relation of...show more

Product details

  • Paperback | 28 pages
  • 189 x 246 x 2mm | 68g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236847687
  • 9781236847683