Hydraulics

“ It is a principle in hydraulics, not easily understood at first by the layman, that the pressure upon a weir or barrage in a river depends entirely upon the difference in level between the water on the upstream and on the downstream side, and not on the mere volume of water in the river behind it. ”

“ It has been made by “men who know for men who care,” for the whole circle of the sciences consists of principles deduced from the discoveries of different individuals, in different ages, thrown into common stock; this is especially so of the science of hydraulics ”

“ They possessed lead pipes of different sizes, and stopcocks of bronze and silver, for these have been found in various places; and that they were perfectly familiar with the principle of hydraulics, that water may be returned to its original level, is proved not only by the construction of the filtering-places already described, but also by the fact that they actually applied the principle on a stupendous scale. ”

“ Hydraulics and hydrology, simply stated, are sciences developed to control the deleterious effects of water. There is adequate evidence that ancient cultures constructed amazingly elaborate conduits, aqueducts and other drainage structures to control the flow of water. In the early development of rail transportation, bridges and culverts were certainly an integral part of the design. With the advent of the automobile and accelerated highway construction programs, drainage and water problems became more critical. ”

“ After the great improvements in the steam engine made by Watt, water, steam and air pressure joined their forces on the threshold of this century to lift and move the world, as it had never been moved before.
The strong hands of hydraulics are pumps. They are divided into classes by names indicating their purpose and mode of operation, such as single, double-acting, lift or force, reciprocating or rotary, etc. ”

“ The distance to which a new obstruction to the flow of a river, whether by a dam or by a deposit in its channel, will retard its current, or, in popular phrase, "set back the water," is a problem of more difficult practical solution than almost any other in hydraulics. ”

“ The Hydraulics of Open Streams.—When any reach of a stream is altered, say by widening, narrowing, or deepening, so that the water-level is changed, there will also be a change in the water-level, a gradually diminishing change, for some distance upstream of the reach. Also in the lowest portion of the reach the change will gradually diminish and it will vanish at the extreme downstream end of the reach. In the next lowest reach there is no change. ”

“ Many physicists who have investigated the laws of natural hydraulics maintain that, in consequence of direct obstruction and frictional resistance to the flow of the water of rivers along their banks, there is both an increased rapidity of current and an elevation of the water in the middle of the channel, so that a river presents always a convex surface. ”

“ The simplicity of the operation of this machine, together with its effectiveness, and very apparent durability, renders it decidedly the most important and 339 valuable apparatus yet developed in hydraulics, for forcing a portion of a running stream of water to any elevation, proportionate to the fall obtained. It is perfectly applicable where no more than eighteen inches fall can be had ”

“ Absence of all obstructing mechanism in the wells allows each to be operated to its full capacity. Production, therefore, does not depend upon the pump, but rather upon the capacity of the well to yield water; the natural yield of wells is often increased by this process of using compressed air admitted87 close to the bottom of the discharge pipe, the water is set in motion at a considerable depth, and by this action the well is “cleaned.” ”

“ Such wells may affect or rob each other, and it is usually best to spread them out on a line across what is known to be the underground flow. Some finely creviced or tight rock formations have a strong head with but little capacity, and wells in such formations, if pumped hard, yield but little additional water. They should be scattered and pumped moderately, maintaining a low and economical lift. In other cases, one well in a group will give as much water as all together, and more territory must be drawn on. ”

“ Consequently, when the piston ascends, it no longer forces the water into M, the air of the reservoir, by the pressure it has received, reacts on the liquid, and raises it in the tube D, until the piston again descends, so that the jet is continuous.
Hydraulic Machine Tools. Probably in no department of engineering has the use of hydraulic power met with more success than in its application to certain machine tools. ”

“ Wherever a stream flows from a higher to a lower level it is possible to erect a water motor. The amount of power obtainable depends on the available head and the supply of water. In choosing a site the engineer will select a portion of the stream where there is an abrupt natural fall, or at least a considerable slope of the bed. ”

“ When attached to a hydrant or plug, do not run the engine faster than the water will flow to supply the pump, and if the supply is not sufficient to allow the pump to work to its full capacity, avoid using too large nozzles. ”

“ Water-pressure has sometimes been applied to operate machines which are worked continuously and not intermittently, and to continuous working rotary machines. This is unwise, for in applying hydraulic power to the continuous working of shafting or shop tools, the amount of power developed by the hydraulic engine cannot be varied to suit the work to be done, neither can the speed be regulated with sufficient nicety. ”

“ From the earliest ages, a vessel suspended by a cord, has been used by all nations—a device more simple and more extensively employed than any other, and one which was undoubtedly the germ of the most useful hydraulic machine of the ancients. ”

“ In these cases, an artificial source of water power is created by using a steam engine to pump water to a reservoir at a great elevation, or to pump water into a closed reservoir in which there is great pressure.
Water flowing from the reservoir through hydraulic engines gives back the energy expended, less so much as has been wasted in friction. Where a continuously acting steam engine stores up energy by pumping the water, while the work done by the hydraulic engines is done intermittently,—this arrangement is considered the most useful. ”

“ After the standing water column has been thrown off by the pressure the air rises through the water reduces its weight, with the result that the water is expelled as fast as the well supplies it, the water outside the pipe, acting as a head, flows into the discharge pipe by the force of gravity. ”

“ It is this principle which operates with such astonishing effect in hydrostatic presses, of which familiar examples are found in the hydraulic pumps, by the use of which boilers are tested. By the mere weight of a man’s body when leaning on the extremity of a lever, a pressure may be produced of upwards of 20 tons; it is the simplest and most easily applicable of all contrivances for increasing human power, and it is only limited by want of materials of sufficient strength to utilize it. ”

“ When water can be had under sufficient head to thus feed itself into the system, and the hot-well can at the same time be so situated as to drain itself, it makes a remarkably simple and efficient arrangement. ”

“ The suitability of water for the transmission of power has been fully recognized in recent years; the facility with which water under pressure is capable of being utilized, and the advantages that attend its use in motors have resulted in many practical difficulties being overcome, which were at first considered insurmountable. ”

“ Hydraulic Shears. A machine for shearing or cutting metals, etc., by the force of water pressure operating cutters.
Hydraulic Valve. A valve for regulating the distribution of water in the cylinders of hydraulic elevators, cranes and other water pressure machines and devices.
Hydraulic Wheel. One for raising water by applied power, as the Noria Scoop wheel, tympanum, etc. See illustrations in section relating to the history of the pump.
Impact. The single instantaneous shock of a body in motion when it strikes against another body either in motion or at rest. ”

“ In cities where the water distribution is from elevated reservoirs, and in which the water supply is sufficiently abundant to justify the application of a portion of it to industrial uses, the water-engine or motor is recommended. ”

“ Between the place where the water of an aqueduct is delivered and the spring, the ground may rise into hills and descend into valleys, and the pipes which convey the water may follow all the undulations84 of the country, and the water will run freely, provided no pipe is laid higher than the spring. ”

“ For low heads of liquids the rotary is also somewhat more efficient than direct acting pumps and the absence of close fitting parts renders it possible to handle water containing a considerable quantity of impurities, such as silt, grain and gravel. ”

“ With this pump, water may be raised from several hundred feet below the surface by extending the shaft and runners down the well-casing to the desired depth; it being always necessary to submerge the lower runner. ”

“ The animals descend by this passage to drive the machinery that raises the water from the lower shaft into the reservoir or basin, from which it is again elevated by similar machinery and other oxen on the surface of47 the ground. In the lower shaft a path is also cut down to the water, but as no partition is left between it and the well, it is extremely perilous for strangers to descend. ”

“ When the piston rises from the bottom of the cylinder B, a vacuum is produced below, and the valve O is kept closed by the atmospheric pressure, while the air in the pipe A, in consequence of its elasticity, raises the valve S, and part of it passes into the cylinder. The air being thus rarefied, water rises in the pipe until the pressure of the liquid column, together with the pressure of the rarefied air which remains in the tube, counterbalances the pressure of the atmosphere on the water in the reservoir. ”

“ Water under pressure conveyed in pipes is a convenient and economical means of transmitting energy and distributing it to many scattered working points. Hence large and important hydraulic systems are adopted in which at a central station water is pumped at high pressure into distributing mains, which convey it to various points where it actuates hydraulic motors operating cranes, lifts, dock gates, and in some cases riveting and shearing machines. ”

“ Water for sluicing operations is frequently brought from great distances through canals, ditches, or flumes, the proprietors of which sell the water to miners at so much the miners' inch, a miners' inch being in most localities the quantity flowing in a given time through an aperture one inch square under a head of six inches.—The celebrated hydraulic process, invented in Placer co., Cal., in 1852, consists in washing down the whole surface and underlying mass of auriferous deposits, preparatory to sluicing. ”

“ The hydraulic process is applied only in claims where the dirt is deep and where the water is abundant. If the dirt were shallow in the claim and its vicinity, the necessary head of water could not be obtained. Hydraulic claims are usually in hills. The water is led along on the hill at a height varying from fifty to two hundred feet above the bed-rock, to the claim at the end or side of the hill, where the water, playing against the dirt, soon cuts a large hole, with perpendicular or at least steep banks. ”

“ The kind of water system, like the supply, is governed by geography and geology. If there happens to be a spring on a nearby hillside somewhat higher than the house, nature has provided the cheapest and simplest system. A pipe line and storage tank are all that are needed. Gravity does the rest. On the other hand, if the spring is on the same level or lower than the house, a pump must be added to the equipment to force the water into the pressure tank and out of the faucets. If the spring has a large flow and adequate drainage, a water ram is advisable. ”

“ Hydraulic jack, a jack or lifting apparatus, by means of oil, &c., pressed by a force-pump against a piston or plunger; Hydraulic mining, a method of mining by which the auriferous detritus is washed down by a powerful jet of water into a sluice where the gold is easily separated; Hydraulic press, a press operated by the differential pressure of water on pistons of different dimensions; Hydraulic ram, an automatic pump worked by the pressure of a column of water in a pipe, and the force acquired by intermittent motion of the column. ”

“ The pressure of water is always in proportion to its height or head, without reference to the extent of surface. The pressure, then, of the water against the cemented wall, would be equal to the pressure of a full mill-pond against its perpendicular dam of six or eight feet height! No sane man would think of tightening a dam, with seven feet head of water, by plastering a little cement on the down-stream side of it, which might as well be done, as to exclude water from a cellar by the process, and under the conditions, stated. ”

“ Eads thus clearly outlined, in 1874, 1876, and 1878, one of the most magnificent plans which hydraulic engineering has ever undertaken. It is not simply to save thirty thousand square miles of land as rich as the Delta of Egypt from devastating inundations, but to extend deep water from the Gulf of Mexico to the mouth of the Ohio, into the very heart of the Mississippi Valley, while permanently locating this magnificent channel by practically putting an end to the caving of its banks. ”