Water-power; an outline of the development and application of the energy of flowing water . the consecutive shutters, and thata great volume of leakage must result. These gaps are closedby square pieces of scantling, as indicated at Fig. 77/;, thepressure of the water holding the scantling firmly in its place. We come now to the two forms of movable dam whichhave received the most extended application; the needle damand the wicket dam. These have one feature in common,viz., each requires a temporary foot-bridge for its erection andremoval. The Poir^e Needle Dam, so called from its
Water-power; an outline of the development and application of the energy of flowing water . the consecutive shutters, and thata great volume of leakage must result. These gaps are closedby square pieces of scantling, as indicated at Fig. 77/;, thepressure of the water holding the scantling firmly in its place. We come now to the two forms of movable dam whichhave received the most extended application; the needle damand the wicket dam. These have one feature in common,viz., each requires a temporary foot-bridge for its erection andremoval. The Poir^e Needle Dam, so called from its Poiree, an officer of the French engineer department,was first applied in France about the year 1834. A generalidea of the device will appear from Tig. 78, which is an eleva-tion of the dam in process of erection, Fig. 78^ a plan, andFig. 78^ a cross-section. It is supposed to extend across achannel of any required width with vertical side walls or abut-ments. One of the abutments has a recess into which theadjoining trestles fall. The construction and manipulation of 164 MOVABLE ^r^ Fig. 78.
Size: 2442px × 1024px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjecthydraulicengineering
