File:Modern mechanism, exhibiting the latest progress in machines, motors, and the transmission of power, being a supplementary volume to Appletons' cyclopaedia of applied mechanics (1892) (14583751309).jpg

Identifier: modernmechanisme00benj (find matches)
Title: Modern mechanism, exhibiting the latest progress in machines, motors, and the transmission of power, being a supplementary volume to Appletons' cyclopaedia of applied mechanics
Year: 1892 (1890s)
Authors: Benjamin, Park, 1849-1922
Subjects: Mechanical engineering
Publisher: New York, D. Appleton
Contributing Library: Mugar Memorial Library, Boston University
Digitizing Sponsor: Boston University

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ly. The pumps, which aredouble-acting, are each fitted with 700 Troy valves, each of about U in. diameter andI in. lift. At each end of each pump, therefore, there are 175 induction and 175 eductionvalves, giving an aggregate valve opening for the reception and discharge of the water equalto more than 0-6 of the effective area of the plunger. The loss of head due to the passageof the water through the pumps is probably not greater than 0 • 25 of a foot. Steam is furnished to this engine by two horizontal cylindrical boilers, of the followingproportions : Total area of grate surface, 66 sq. ft. Total heating surface, (about) 2,866 684 PUMPS, RECIPROCATING. SQ ft Total are^ of cross-section of tubes, 7-18 sq. ft. Total area of chimney flue, 8-33so ft Ratio of heating surface to grate surface, 43.42. Ratio of grate surface to areathrouo-h tubes 9 19. Ratio of grate surface to area of chimney flue, 7-92. The following average values are obtained from the records of the test : Mean steam
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pressure in boilers, per gauge, 81-05 lbs. Mean steam pressure at engine, per gauge, 78-01lbs Mean steam pressure in jackets, per gauge, 70-075 lbs. Mean water pressure, pergauge, 99-565 lbs. Total mean pressure on pumps, corrected, 103-735 lbs. Mean vacuum,per gauge on condenser, 28-9 in. Mean vacuum, per gauge on engine, 27-87 in. Meantemperature of feed water, 203-55° F. Mean volume of water, at 51°, passing the meter per PUMPS, EEClPROCATmG. 685 hour, 88014 cu. ft. Mean revolutions of engine, per minute, 17-04. Mean effective area ofplunger, 481 0575 sq. in. Mean rate of coal consumption, per hour, 600 lbs. Mean rateof consumption per hour per square foot of grate, 9-091 lbs. Mean rate of evaporation inboilers, per minute. 96-135 lbs. Substituting in the dutv formula the values found, for the duty. 117,936,698 ft. lbs.,on the basis of the assumed evaporation of 10 lbs. of water per pound of coal, this resultexceeds the guaranteed dutv, 105,000,000, by 12-33 per cent., or by near

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