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December, 1913 sible, however large may condenser and in the pump are equal. lf, however, the pump is made colder than the condenser the -pressure in the pump falls and air flows into the the air punip be, because the pressure in the pump. The greater the difference in temperature between the pump and the condenser the greater is the dif- ference in pressure and the greater will be the quantity of air the pump can withdraw. Obviously, therefore, the withdrawal of air and water by // CONTRAFLO CONDENSER AND TEMPERATURE REGULATOR AIR, PUMP SUCTION one pump introduces a compromise, for in order 'to: withdraw ai "and allow the condenser to do its work effectively the air pump has to be relatively cold, but in order to obtain high thermal efficiency the tempera- ture of the feed water must be rela- tively hot. In order to conserve heat the water passing through the air pump must be as hot as_ possible relatively to the temperature in the condenser. In order to adjust these conditions as far as ever possible the air pump temperature regulator has been intro- duced, the actions of which will be seen from the illustration. tom of the condenser is provided with a divided off receiver which is always kept filled with condenser water. Above this receiver is a shal- low chamber in which the air is de- vaporized as it flows towards the air pump suction pipe. The devaporizing chamber is divided from the con- densing department by one or more diaphragms on to which the water of condensation falls and from which it _passes either to the air pump or to the water charged receiver or partly to both. The -flow of the water is regulated by a change valve and the inlet pipe of the receiver provides sufficient head to cause the water to circulate. If when the feed water passes direct from the condenser chamber to the air pump suction pipe the air. pump is able to prevent any sccumiulation "of the air im tne con- The bot- THE MARINE REVIEW denser, then the air withdrawal ca- pacity of the pump is obviously suf- ficient. If, however, the pump can- not prevent air accumulation in the condenser the vacuum falls. Under such circumstances the air withdraw- ing capacity of the pump can be im- mediately increased by lowering its temperature, and this can be effected by passing some water from the con- densing chamber through the water charged receiver. In- this: way.- the air withdrawing capacity' of the pump can be increased at will and a vacuum maintained in a way which would be impossible by any other mearis even if two ordinary sized pumps were fitted instead of one. It is tempera- ture and not size, which controls the air withdrawing capacity of an air pump. For -this reason a higher vacuum can be maintained in a steady manner in all seas when the temper- ature regulator is used in combina- tion with a single air pump. with- drawing both air and water than has hitherto been possible even with an air pump of abnormal size. The great importance of maintain- ing a. good vacuum under all condi- tions is so thoroughly understood by marine engineers that further stress need not be laid on the im- portant nature of this development, which is of first class importance for any vessel where steaming economy has to be realized. Obituary Dr... S: J.-P, DThearle, chief ship sur- veyor to Lloyds Register of British and Foreign Shipping, died on Nov. 14 at his residence, 74 St. Augustine's avenue, South Corydon, London. Dr. Thearle, whose name was known all over the world as that of an authority on naval architecture, was born at Portsmouth in 1846. In 1860 he was apprenticed as a_ ship- wright in Devonport Dockyard, where the late Sir William White, K. C. B., was also at that time learning his pro- fession. In 1865 he was_ included among four students selected by the 'Admiralty to undergo a three years' course of study at the then newly formed Royal Naval School of Archi- tecture. At the conclusion of this course he was granted the diploma of Fellow and appointed dockyard draughtsman. In 1872 he became draughtsman at the Admiralty, and in 1876 he offered himself as-a candi- date for a surveyorship in the service of Lloyds Register. To this he was duly elected, and he served success- in London, Bristol, Greenock He served at Green- ively and Glasgow. 429 ock from 1883 'till 1887, and at Glas- gow from 1887 till 1897, so that he spent about 14 years in the Clyde dis-. trict. In 1898 he was appointed prin- cipal surveyor at Newcastle. In 1900 he was transferred to London as as- sistant to the chief ship surveyor, to" which position H. J. Cornish had then succeeded. Dr. Thearle was appointed successor to Mr. Cornish when the latter gentleman retired in 1909, and he was the society's chief ship sur- veyor from that date until his death. Dr. Thearle was the author of five valuable books on naval architecture. The earliest was an elementary treat- ise on "Laying Off Wood and Iron Ships". It was published in 1873, The latest was "Thearle's Modern Practice of Shipbuilding in Iron and Steel". It was originally published in 1887, and was rewritten recently. These works have always been recognized as standard text books at the various schools of naval architecture and by the royal dockyards and the board of trade. Another of Dr. Thearle's bet- ter known volumes was "Theoret- ical Naval Architecture', which was published in 1876. In 1893 the committee of Lloyds: selected Dr. Thearle to accompany Mr. Cornish on a visit to the Great Lakes of North America for the pur- pose of conducting investigations into the shipbuilding industry in that dis- trict, and reporting thereon for their information. Dr. Thearle wasavery familiar figure at all gatherings of shipbuilders and marine engineers, particularly at meet- ings of the Institution of Naval Arch- itects, the North-East Coast Institu- 'tion of Engineers and Shipbuilders, and kindred bodies. He read papers frequently on technical subjects at these meetings, and his contributions in this way to the literature of ship- building were of considerable impor- tance. He read a paper on "Some Cases of Fatigue in the Steel Mate- vial of Steamers" at the summer meet- ing of the Institution of Naval Archi- tects and the Institution of Engineers and Shipbuilders in Scotland in Glas- -- gow this year, and took a leading part in the other proceedings. He was a member of the council of the Institu- tion of Naval Architects and a vice president. He was a member of the present departmental committees on bulkheads and watertight compart- ments, and of that on the load line, and he had accepted an invitation to deliver the next James Watt anni- versary lecture at Greenock. In 1910 he received the honorary degree of doctor of science from the University of Durham.