CHAPTER II
Appliances for Distributing Water
We have so far discussed only the various sources of potable water. We must now turn our attention to the mechanical means for making it available for use, which comprise appliances for lifting, storing, conveying, distributing, and purifying the water.
The location of the source of supply with reference to the buildings and grounds decides generally the question whether a gravity supply is feasible or whether water must be pumped. The former is desirable because its operating expenses are almost nothing, but it is not always cheapest in first cost. Rather than have a very long line of conduit, it may be cheaper to pump water, particularly if wind or water power, costing nothing, can be used.
Machines for Pumping
When it becomes necessary to pump water, there are numerous machines from which to choose; only the more important ones will be considered. We may use pumps operated by manual labor, those run by animal power, pumping machinery using the power of the wind or that of falling or running water; then there are hot-air, steam, and electric pumps, besides several forms of internal-combustion engines, such as gas, gasoline, and oil engines. Each has advantages in certain locations and under certain conditions.
Of appliances utilizing the forces of Nature, perhaps the simplest efficient machine is the hydraulic ram. While other machines for lifting water are composed of two parts, namely, a motor and a pump, the ram combines both in one apparatus. It is a self-acting pump of the impulse type, in which force is suddenly applied and discontinued, these periodical applications resulting in the lifting of water. Single-acting rams pump the water which operates them; double-acting rams utilize an impure supply to lift a pure supply from a different source.
The advantages of the ram are: it works continuously, day and night, summer and winter, with but very little attendance; no lubrication is required, repairs are few, the first cost of installation is small. Frost protection, however, is essential. The disadvantages are that a ram can be used only where a large volume of water is available. The correct setting up is important, also the proper proportioning in size and length of drive and discharge pipes. The continual jarring tends to strain the pipes, joints, and valves; hence, heavy piping and fittings are necessary. A ram of the improved type raises water from twenty-five to thirty feet for every foot of fall in the drive pipe, and its efficiency is from seventy to eighty per cent.
Running water is a most convenient and cheap power, which is often utilized in water wheels and turbines. These supply power to run a pump; the water to be raised may come from any source, and the pump may be placed at some distance from the water wheel. Where sufficient fall is available—at least three feet—the overshot wheel is used. In California and some other Western States an impulse water wheel is much used, which is especially adapted to high heads.
Windmills Used for Driving Pumps
The power of the wind applied to a windmill is much used for driving pumps. It is a long step forward from the ancient and picturesque Dutch form of windmill, consisting of only four arms with cloth sails, to the modern improved forms of wheels constructed in wood and in iron, with a large number of impulse blades, and provided with devices regulating the speed, turning the wheel out of the wind during a gale, and stopping it automatically when the storage tank is filled. The useful power developed by windmills when pumping water in a moderate wind, say of sixteen miles an hour velocity, is not very high, ranging from one twenty-fifth horse-power for an eight and one-half foot wheel to one and one-half horse-power for a twenty-five foot wheel. The claims of some makers of windmills as to the power developed should be accepted with caution.
The chief advantage is that, like a ram, the windmill may work night and day, with but slight attention to lubrication, so long as the wind blows. But there are also drawbacks; it requires very large storage tanks to provide for periods of calm; the wheel must be placed sufficiently exposed to receive the full wind force, either on a tower or on a high hill, and usually this is not the best place to find water. Besides, a windmill tower, at least the modern one, is not an ornamental feature in the landscape. It is expensive when built sufficiently strong to withstand severe winter gales. During the hot months of the year, when the farmer, the gardener, and the coachman require most water, the wind is apt to fail entirely for days in succession.
The Use of Engines
If water is not available, and wind is considered too unreliable, pumping must be accomplished by using an engine which, no matter of what form or type, derives its energy from the combustion of fuel, be the same coal, wood, charcoal, petroleum or kerosene, gas, gasoline, or naphtha. The use of such pumping engines implies a constant expense for fuel, operation, maintenance, and repairs. In some modern forms of engines this expense is small, notably so in the oil engine, and also in the gasoline engine; hence these types have become favorites.
Advantages of Pumping Engines
An advantage common to all pumping engines is that they can be run at any time, not like the windmill, which does not operate in a light breeze, nor like the ram, which fails when the brook runs low. Domestic pumping engines are built as simple as possible, so that the gardener, a farm hand, or the domestic help may run them. Skill is not required to operate them, and they are constructed so as to be safe, provided ordinary intelligence is applied.
In using a fuel engine it is desirable, because of the attendance required, to take a machine of such capacity and size that the water supply required for two or three days may be pumped to the storage tank in a few hours.
Expansive Force of Heated Air Utilized
A favorite and extensively used type of domestic pump is the hot-air engine, in which the expansive force of heated air is used to do useful work. Among the types are simple and safe machines which do not easily get out of order. They are started by hand by giving the fly wheel one or more revolutions. If properly taken care of they are durable and do not require expensive repairs.
Gas and Gasoline Engines
In gas engines power is derived from the explosion of a mixture of gas and air. Where a gas supply is available, such engines are very convenient, for, once started, they will run for hours without attention. They are economical in the consumption of gas, and give trouble only where the quality of gas varies.
Owing to the unavailability of gas on the farm and in country houses, two other forms of pumping engines have been devised which are becoming exceedingly popular. One is the gasoline, the other is the oil engine. Both resemble the gas engine, but differ from it in using a liquid fuel which is volatilized by a sprayer. Gasoline engines are now brought to a high state of perfection.
Kerosene or Crude Oil as Fuel
In recent years, internal-combustion engines which use heavy kerosene or crude oil as fuel have been introduced. These have two palpable advantages: first, they are safer than gasoline engines; second, they cost less to run, for crude oil and even refined kerosene are much cheaper than gasoline. Oil engines resemble the gas and gasoline engines, but they have larger cylinders, because the mean effective pressure evolved from the explosion is much less than that of the gasoline engines.
Oil engines for pumping water are particularly suitable in regions where coal and wood cannot be obtained except at exorbitant cost. Usually, the engine is so built as to be adapted for other farm work. It shares this advantage with the gasoline engine. Oil engines are simple, reliable, almost automatic, compact, and reasonable in first cost and in cost of repairs. There are many forms of such engines in the market. To be successful from a commercial point of view, an oil engine should be so designed and built that any unskilled attendant can run, adjust, and clean it. The cost of operating them, at eight cents per gallon for kerosene, is only one cent per hour per horse-power; or one-half of this when ordinary crude oil is used. The only attention required when running is periodical lubrication and occasional replenishing of the oil reservoir. The noise of the exhaust, common to all engines using an explosive force, can be largely done away with by using a muffler or a silencer. The smell of oil from the exhaust likewise forms an objection, but can be overcome by the use of an exhaust washer.
Steam and Electric Pumps
The well-known forms of steam-pumping engines need not be considered in detail, because high-pressure steam is not often available in country houses. Where electric current is brought to the building, or generated for lighting purposes, water may be pumped by an electric pump. Electric motors are easy and convenient to run, very clean, but so far not very economical. Electric pumps may be arranged so as to start and stop entirely automatically. Water may be pumped, where electricity forms the power, either by triplex plunger pumps or by rotary, screw, or centrifugal pumps.
Pumps Worked by Hand
Space forbids giving a description of the many simpler devices used for lifting water. In small farmhouses lift and force pumps worked by hand are now introduced, and the old-fashioned, moss-covered draw-bucket, which is neither convenient nor sanitary, is becoming a relic of past times.
Reservoirs and Storage Tanks
The water pumped is stored either in small masonry or earth reservoirs, or else in storage tanks of either wood, iron, or steel, placed on a wood or steel tower. Wooden tanks are cheap but unsightly, require frequent renewal of the paint, and give trouble by leaking, freezing, and corrosion of hoops. In recent years elevated tanks are supplanted by pressure tanks. Several such systems, differing but little from one another, are becoming quite well known. In these water is stored under suitable pressure in air-tight tanks, filled partly with water and partly with air.
A Simple Pressure System
One system consists of a circular, wrought-steel, closed tank, made air- and water-tight, a force pump for pumping water into the tank, and pipe connections. The tank is placed either horizontally or vertically in the basement or cellar, or else placed outdoors in the ground at a depth below freezing. Water is pumped into the bottom of the tank, whereby its air acquires sufficient pressure to force water to the upper floors.
This simple system has some marked advantages over the outside or the attic tank. In these, water gets warm in summer and freezes in winter. Vermin and dust get into the tank, and the water stagnates. In the pressure tank, water is kept aërated, cool, and clean.
Another pressure tank has an automatic valve, controlled by a float and connected with suction of pump. It prevents the tank from becoming water-logged by maintaining the correct amount of air inside.
An Ideal System for a Country House
Still another system using pressure tanks is more complete than either of the others, comprising engine, pump, air compressor, a water tank, and also an air tank. It is best described by a recent example constructed from plans and under the direction of the writer. The buildings supplied with water comprise the mansion, the stable, the cottage, and a dairy, and the pumping station is placed near the shore of the lake from which the supply is taken. See Figs. [1] and [2].
DIAGRAM OF COMPRESSED AIR TANK SYSTEM.
Fig. 2.
PRESSURE-TANK PUMPING STATION.
Interior view of pumping station of compressed air-tank system (see [plan] on opposite page) showing 3,000 gallon water tank, air tank of 150 pounds pressure and 10 horse-power gasoline engine.
The pump house is about 20 feet by 27 feet, and contains a water-storage tank 6 feet in diameter and 131/2 feet long, of a capacity of 3,000 gallons; an air tank of same dimensions as the water tank, holding air under 150 pounds pressure; a 10 horse-power gasoline engine, direct-connected, by means of friction clutch, with an air compressor and also with a triplex pump of 75 gallons capacity per minute.
The water in the tank is kept under 75 pounds pressure, and at the hydrant near the house, located about 100 feet above the pumping station, there is an available pressure of 33 pounds. The last drop of water flows from the water tank under the full pressure of 75 pounds at the pumping station. The suction pipe into the lake is 4 inches and is provided with well strainers to prevent clogging.
The cost of pumping water by this system is quite reasonable. The gasoline engine requires per horse-power per hour about 11/4 gallons of gasoline, and at sixteen cents per gallon this makes the cost for 1,000 gallons pumped about five cents. To this expense should, however, be added the cost of lubricating oil, repairs, amount for depreciation, and the small cost for labor in running the engine.
Water pipes forming a distribution system should always be chosen generous in diameter, in order to avoid undue loss of pressure by friction. Where fire hydrants are provided, the size of the water main should not be below four inches. All branches should be controlled by shut-offs, for which the full-way gate valves are used in preference to globe valves. Pipe-line material is usually galvanized, screw-jointed wrought iron for sizes up to four inches.
In conclusion, a word about water purification. Where the quality of the water supply is not above suspicion it may be improved by filtration. A filter should never be installed without the advice of a qualified expert, for there are numerous worthless devices and few really efficient ones. Where a filter is not available, the water used for drinking should be boiled or sterilized if there is the slightest doubt as to its wholesomeness.