PUMPS AND PUMPING. 54:5 PUMPS AND PUMPING. 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 1851. 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 IGIS. A column of water was raised by means of a vertical piston, driven by the weight or pressure of a second and higher column. 'alves 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 17311 Beli- 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 case 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 puxnp. 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 tijnritalia ; this, while showing a knowledge of the principle, was merely a toy. In 1605 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 sliaft, 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 1S60 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 f^lwne ejector. It ■was invented by I, Shone, of Wrexam. England, who brought it before the public in 1878. 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 Seweb.^ge. ) The vacuum principle, as used in vacuum pumps, is used for other purposes, but the efficiency of these machines is low and their general scope of application is otherwise limited. The air-lift pump was suggested by Freiburg, in a pamphlet i)ublished in 17'J7; described in an English translation (1876) of lectures on mining by t'allon ; patented by .Jos, P. Frizzell, of Boston, in 1880 : and used in Berlin, Gernianv. 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 1SS8 Pohle exhibited an air-lift pump at Alameda, C'al., and in 1802 he secured patents on it. In the following ten years the Pohle and various other air-lift pumps were adopted for raising water from deep wells at many municipal and private water-supply plants. Tlie development of the steam pumping engine was foreshadowed by the steam fountain of Hero; the improved steam fountain of the Italian Porta, described by him in 1601, in which a separate boiler was used: and the inventions of tlie Marquis of Worcester, who is supposed to have been the first to put tliis device in practical operation for raising water intermittently. He also used a separate boiler and displaced water intermittently from a closed vessel by steam pressure. In 1663 Worcester secured patents on an improvement of this device. A separate boiler supplied steam alternately to two vessels placed over the water to be lifted and connected thereto by means of pipes. The condensation of steam in the vessel created a vaciuim. whereupon atmos- pheric pressure filled this chamber with water from below. ileanwhile steam displaced the water in the other vessel. This was a forerunner of the pulsometer pump, described above. Xext in order of importance among those to whom we are indebted for the pumping engine comes Thos. Savery, who in 1608 patented the first pumping engine used to drain the mines of Corn- wall. In 1702 he published a pamphlet. The Miners' Friend, in which he described his device and its advantages. The water-raising features of this machine were essentially the same as those of Worcester, but Savery added a surface con- denser and a second or feed-water boiler. In 1600 Denis Papin suggested steam as a substi- tute for gunpowder to move a piston. In 1705 Thomas S'ewcomen, .Tohn Calley. and Savery pat- ented a pumping machine which combined a steam piston, outside condenser, balanced beam, pump rods, and a bucket piston pump. On applying the condensing jet a vacuiun was created beneath the piston, whereupon atmospheric pressure forced the piston dom and with its fall the steam end of the beam also fell, while the water end, with the pump rods and pump, was lifted. When steam was admitted beneath the piston, the
