Steam using; or, Steam engine practice

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. 1885 edition. Excerpt: ...from 0.6 m. to 0.8 m., the water brought from the condenser. The discharge of this orifice is found experimentally by closing it tightly by a stopper, filling to a known height and noting the time it takes to lower each 0.1 m. Let S be the horizontal section of the pit, a the area of discharge, and n an unknown coefficient of contraction, h the head above the centre of the orifice, and t the time. We then have:--Sdh = nadt V2gh 2 & WH0--VH1 = nsTVig nsV'ig = %P W'H0-V/A) This gives at once ns V2g when the time T is noted, while the level falls from H0 to if,. The volume of water, or the weight rather, running out under head H, is 77= (ns v"20) VH. During the days of experiments we noted every fifteen minutes the heads h„ h„ h,... these varied little and VIlm = Vh + V-t ±; or, more simply even 'N whence II = (ns VW1 Vhm ± S ft, and fc, are initial and final heads of an experiment whose duration was T. If in this time the engine made B strokes the weight of water rejected IT 7 per stroke was //„ =. The injection per stroke was II--M. B We give in tabular form the values obtained in eight experiments, each consuming an entire day: Tabl' I. 2. Temperatures.--Part of these are noted directly, but with different instruments. To arrive at the superheating a good thermometer is simply placed in mercury in a copper pocket open at one end and closed at the other and let into the steam pipe; this measurement is easy to obtain. The rise of temporature of the injection water in the condenser necessitates a more careful measurement--a special thermometer known already to the readers of our Bulletins, the differential air thermometer. The practical arrangements that M. Hir n brought about this instrument permitted...