Hydro-electric practice; a practical manual of the development of water power by Schon Hans August Evald Conrad von 1851-

Author:Schon, Hans August Evald Conrad von, 1851- [from old catalog]
Language: eng
Format: epub
Tags: Hydroelectric power plants
Publisher: Philadelphia & London, J. B. Lippincott company
Published: 1911-03-25T05:00:00+00:00

I

Longitudinal Section

il

Transverse Sectton

M

Concrete Fishladder

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Tiansverse Section

H.E.P.133 av,S-

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during a non-operating period. In this manner the upper pool by pondage is utilized as a storage reservoir, principally during the low-flow periods, by placing some movable addition upon the spillway crest, arresting and holding the natural flow in the upper pool, no water being allowed to overflow the spillway or pass through the turbines during a certain period, generally some portion of the night, and then using the natural flow plus the accumulated volume during the operating period. When this proceeding is feasible,—which is not always nor generally the case, because it interferes with and disturbs the natural conditions of the flow in the stream and thereby is likely to interfere with the rights and ownership, in and to the water, of others,—and when the operating period can be confined to ten hours, the power output of the continuous flow can in this manner be practically doubled.

Many different devices are employed for flashboard service, mechanical, automatic, and hand operated, but their selection should be guided by the conditions under which they are to be used as relating to seasons, periods, and frequency of their service. When they are to be employed during the winter, in northern latitudes, the ice conditions must be considered. Fig. 73 shows different types of flashboards. In sections I and II a plank flashboard is set on edge upon the spillway crest resting against strain pins, inclined downstreamward and placed into holes left in the spillway masonry, or between such strain pins, the latter being arranged in a double row and staggered; these planks may be so placed by being handled from a platform above or from flat-boats held in place above the spillway by guide-lines secured to shore points or to a ferry line crossing the stream above the spillway. This type of flashboards answers well during open seasons for short spillways; the strain pins are of one-inch wrought iron; it is advisable not to fix them permanently into the masonry, but to leave holes into which they are readily set; the planks should be two inches thick and from 8 to 12 inches wide, though the narrower size will be found preferable on account of the greater ease of handling them; and the planks have secured to them, on their sides, iron hooks so set that they can easily be grappled into. The planks must be of uniform thickness and edged so that they will match up to a water-tight wall in any position. It requires two men to set or remove these flashboards; they are inexpensive and can be quickly handled.

Sections III and IV show a shutter fxishboard framed of two or three planks in lengths from 6 to 10 feet and swung from rod hinges on the

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STRUCTURAL TYPES

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upstream side of the spillway. The shutter is bound by iron strapping and has secured to it two or more strut rods by which the shutter is supported in an upright or inclined position when erected, these rods falling into recesses or grooves left in the spillway crest for that purpose.

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