. Cassier's magazine . zon-tal engine is, on the whole, probablythe favourite, and is made also by the DRIVING OF COTTON MILLS 3 same firms who also build triple-expansion engines. To return for a moment to and 8, showing the steam dashpotgear of the Hick, Hargreaves & Co. en-gine, Corliss valves have been usuallyclosed by steam, by vacuum or byspring pots. Now the resistance tomovement of a Corliss valve is vari-able and depends on the difference ofpressures on either side of its rub-bing face. In a factory where theidle load amounts to 20 per cent, of small steam pressure in the cylin
. Cassier's magazine . zon-tal engine is, on the whole, probablythe favourite, and is made also by the DRIVING OF COTTON MILLS 3 same firms who also build triple-expansion engines. To return for a moment to and 8, showing the steam dashpotgear of the Hick, Hargreaves & Co. en-gine, Corliss valves have been usuallyclosed by steam, by vacuum or byspring pots. Now the resistance tomovement of a Corliss valve is vari-able and depends on the difference ofpressures on either side of its rub-bing face. In a factory where theidle load amounts to 20 per cent, of small steam pressure in the cylinderis too far removed from the steamchest pressure and the valves underthis unbalanced loading may fail toclose. Hence the use of Hick, Har-greaves & special dashpots ofFigs. 13, 7 and 8, which overcomesthe difficulty automatically. The dashpot has an upper steamcylinder and a lower air cushion cyl-inder in one casting attached to thevalve bonnet. In the steam cylinderis a plain piston exposed on its upper. FIG. 14. ENLARGED VIEW OF CORLISS GEAR. HICK, HARGREAVES & CO., LTD. the full working load the pressure ofsteam is fairly constant during ad-mission, and plain dashpots will dothe work with satisfaction and regu-larity, though sometimes they mayneed a little help by throttling thesteam at the stop valve during mini-mum load periods. But if called onto deal with fluctuating load of elec-tric generation, which sometimes mayvary from mere friction to an over-load of 50 per cent., such plain dash-pots will not meet the case, for the side to the steam chest and on itsunderside to the cylinder piston rod of this cylinder islarger than needed for strength, itsarea acted on by the differential ofthe pressures being sufficient to over-come inertia and friction of the parts,while the variable and larger part ofthe load comes under the charge ofthe remaining annular area of thepiston. Thus the steam cylinder is propor-tioned to close the valve under its 312 CASSIERS M
Size: 1808px × 1382px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyork, booksubjec
