═══════════════════════════╤═════════════════════╤═════════════════════ │ LOW-PRESSURE OIL │ DIESEL ENGINE. │ ENGINE. │ │ Three- Half │ Three- Half │Load. quarter Load. │Load. quarter Load. │ Load. │ Load. ───────────────────────────┼─────────────────────┼───────────────────── 1 Fuel per hp-hour │1 lb. 1.25 1.60 │ 0.50 0.55 0.60 │ lb. lb. │ lb. lb. lb. 2 Fuel per hp-year (4,500 │ 643 803.5 1028.5│321.5 353.5 386 hours) │gals. gals. gals. │gals. gals. gals. │ │ 3 Cost of fuel │ 3 cents per gallon │ 3 cents per gallon │ │ 4 Cost of fuel per year │$19.30 $24.10 $30.85│$9.65 $10.60 $11.58 5 Cost of attendance per │ 0.25 cent │ 0.30 cent hp-hour │ │ 6 Cost of attendance per │ $11.25 │ $13.50 year │ │ 7 Lubricating oil per │ 0.006 pint │ 0.007 pint hp-hour │ │ 8 Cost of oil per year at │ $0.84 │ $0.98 25 cents per gal. │ │ 9 Scrubber and cooling │ 5 gals. │ 4 gals. water per hp-hour │ │ 10 Cost of water per year │ │ at 30 cents per 1,000 │ 0.90 │ 0.72 cubic feet │ │ 11 Operating expenses; │$32.29 $37.09 $43.84│$24.85 $25.80 $26.78 items, 4, 6, 8 and 10 │ │ 12 Saving by Diesel engine │ 7.44 11.29 17.06 │ ... ... ... 13 Interest, depreciation │ │ and maintenance │ 6 + 7 + 2 = 15% │ 6 + 10 + 3 = 19% respectively in per │ │ cent of investment │ │ 14 Assuming $80 initial │ │ cost per hp. the │ $12.00 │ $15.00 yearly fixed charges │ │ will be │ │ ───────────────────────────┴─────────────────────┴───────────────────── From a Paper Read Before the American Institute of Electrical Engineers. CHAPTER XIV THE STEAM TRACTOR (147) The Steam Tractor. The steam tractor consists of the following elements, which will take up in detail under separate headings. (1) Engine proper, consisting of the cylinder, piston, valve motion, guides, crank, fly wheel, etc. (2) Boiler—with the grates, burners, etc. (3) Feed pump or injector. (4) Feed water heater.