Synopsis
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. 1905 Excerpt: ...with. There are some people who maintain that steel as well as iron castings cannot be made so tight against air as against steam pressure, but I believe that this difficulty could be overcome by keeping such castings as cylinder valve boxes and the like under steam pressure for some time, so that the pores might get rusted up and closed. I do not quite agree with Mr. Behr that the re-heating with the Cummings system will not be an improvement in economy, as every B.T.I", supplied from the heater to the air is directly converted into work, while when generated under the steam boiler the greatest portion of the heat is wasted in generating steam from water, besides there is the friction loss in engine and compressor. Speaking of mechanical efficiency, I beg to express doubt as to the efficiency of 96 7 per cent, obtained by the Boiler Inspection Society in Dortmund, for the following reasons:--If the compressor were fitted with a somewhat erratic governor, it could easily happen that the revolutions per minute might vary within 1 per cent. or more during a single revolution. Supposing now that the compressor develops 400 h.p. when running at 60 revs per min., i.e., 550 x 400 = 220,000 ft. lbs. during 1 sec., and supposing that the fly-wheel weighs..50,000 lbs. and its centre of gravity revolves with v = 50 ft. per sec., then the momentum would be at normal speed:--30,000 502 u ii _x--=1,164,58? ft. lbs. 322 2 and with 1 per cent. acceleration = 30,000 50 52, JoanAn, „-3T/.5-x-9--= 1,188,000 ft. lbs. and the difference = 30.000 (50-5---50s) 30,000 50 25 x x =-----x 32 2 2 32 2 2 23,413 ft. lbs. In other words, the erratic governor might, during one revolution of the compressor admit so much more steam that 2,336 ft. lbs. above the average (t..e,. 2...
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