HISTORICAL SKETCH. The earliest authentic record of a displacement pump, o• of any im provement over the water lifts, seems to be a description of the force pump of Ctesibius of Alexandria, in Hero's Spiritalia. Two single acting vertical pumps were operated alternately by a common beam, or brake, and the two dis charge pipes were connected with an air cham ber and the stream was then thrown from a movable nozzle. Hero also described another device for raising water, in which the expansive power of steam, acting in a closed vessel. was made to displace o• lift water. In the fifteenth century there is evidence of the frequent use of hand pumps in wells, and, in fact, it seems that they may have been well known over a thousand years earlier, for a German translation of Vege tins (Erfurt, 1511) contains an illustration of a suction-lift pump. with a rectangular barrel. The original of this work was dedicated to Valentinian II. (A.D. 375-302). The substitution of a plunger for a piston. in the ordinary force pump, is credited to Sir Samuel Moreland, who obtained an English patent on the device in 1675. His plunger passed through a stuffing box on the upper end of the vertical pump cylinder, while a double-acting force pump, differing somewhat in principle from the one just suggested, was de scribed by La Hire in 1716, in the Memoirs of the French Academy. The rotary piston pump dates from the sixteenth century, or earlier. Serviere (born at Lyons in 1503) describes a number of rotary pumps. including a double interlocking piston pump. The rotary displacement pump has been but little used, and when now employed it is generally for such service as fire protection, where economy of operation is a comparatively minor consideration. See FIRE-ENGINE.
The invention of the centrifugal pump is ascribed to Lemour, who, in 1732, sent to the French Academy a description of a very elemen tary hand pump of this type. An inclined tube was joined to the lower end of the axle and the whole was revolved by a crank at the upper end of the axle. One of the earliest centrifugal pumps to come into practical use was constructed in Massachusetts, in 1818, and was known as the Massachusetts pump. It was like a fan blower, with four right-angled blades. From this time to the middle of the century centrifugal pumps were brought out from time to time, including the Gwynn. Andrews, and Appold. The last was exhibited in England in 1S51. It was a great improvement over all others up to that date and has been a basis for many of the most successful centrifugal pumps built since that time.
A crude form of water pressure pump was described by Fludd in 161S. A column of water was raised by means of a vertical piston, driven by the weight or pressure of a second and higher column. Valves were provided in the delivery tube, much as in the ordinary suction and force lift pump. An automatic three-way cock cut off and wasted the pressure water, whereupon the piston fell by its own weight. About 1739 Ben dor introduced in some French mines what might be termed a single direct-acting horizontal water pressure engine, much like the simplest form of steam pump of the present day. When the pres sure water, which in this ease was also the water being pumped, had forced the corresponding pis ton to the end of the stroke, the water was auto matically diverted beneath both pistons to the air chamber with which the pump was provided, and also to the other end of the pump. This reversed the stroke of both pistons, whereupon the operation was repeated.
The use of compressed air to raise water, the air itself also being compressed by a column of falling water, is described by Hero in his Spirita/ia; this, while showing a knowledge of the principle, was merely a toy. In 1695 Denis Papin of Blois, France. utilized a water fall to compress air and attempted to transmit the air about a mile to a mine and there drive a piston pump. The leakage and friction were so great that the attempt failed. Papin did not try to apply the air pressure directly to the water to be lifted, as described by Hero, but such an application was effected at a mine in Schemnitz. Hungary, in 1755, and continued in use for many years. In this case water was lifted from a shaft 104 feet beneath the surface by water from a spring 140 feet above the mouth of the shaft. The spring water compressed air in a strong copper cylinder at the mouth of the shaft, which, being piped to a second cylinder at the base of the shaft, forced the water up and out through another pipe. The valves connected with this apparatus were operated by hand. A number of patents for raising liquids by ejectors were granted in the United States between 1860 and 1870. At present, where compressed air is used to raise water the compression is effected by air compressors (q.v.). The air is applied in one of three ways: (1) Simple displacement : (2) as a substitute for steam in pumping engines; (3) in the air-lift pump. In all these three cases air is thus used because of its greater mechanical convenience under special conditions, or because of the readiness with which it may be conveyed through pipes at remote and inaccessible points. One of the principal examples of air displacement apparatus now in use is the Shone ejector. It was invented by 1. Shone, of Wrexam. England, who brought it before the public in 187S. Al though available for other purposes. it is chiefly used to lift sewage from relatively small isolated districts. The sewage is received in an air-tight chamber, provided with valves on both the inlet and outlet pipes. Compressed air from a central station rushes in and displaces the sewage in the chamber. The falling sewage, when the chamber is empty, automatically shuts off the air supply. The Liernur system of removing house wastes, developed about the same time as the Shone, makes use of a vacuum instead of compressed air. By this means the wastes are, from time to time, sucked into central chambers, and from there to a single central station, where the air-exhausting pumps are located. (See SEWERAGE.) The vacuum principle, as used in vacuum pumps. is used for other purpose'., but the efficiency of these machines is low and their general scope of application is otherwise The air-lift pump was suggested by Freiburg, in a pamphlet published in 1797; described in an English translation (1876) of lectures on mining by Callon; patented by Jos. P. Frizzell, of Boston, in 1880; and used in Berlin, Germany. about 1885. About the latter date, Professor Elmo G. Harris, of Rolla, Mo., developed an air lift. But the introduction of the device to practical use was largely due to Julius G. Pohle. This man, with a .Mr. Hill. made various applica tions of air to raising water, beginning in 1886. In ISRS Pottle exhibited an air-lift pump at Alameda. Cal.. and in 1892 he secured patents on it. In the following ten years the Tolle and various other air-lift pumps were adopted for raising water from deep wells at many municipal and private water-supply plants.