STEAM TURBINES.

New Zealand Times, Volume XXVIII, Issue 5802, 20 January 1906, Page 10

STEAM TURBINES.

Professor Ripper, M. Inst. C.E., lecturing before members of tho Sheffield Society of Engineers and Metallurgists on ‘‘Some First Principles of Steam Turbine Design,” said in the two great departments of electric power generating and marine work, for the high powers, tho turbine appears to bo supplanting tho rec ip rotating engine. For instance, during the past year tho total horse-power in marine steam engineering alone is no less than 000,000 horse-power, either delivered or on hand. Tho Admiralty have adopted the turbine system for all classes of ships, including the newest and most powerful battleships. The leading engineering and shipbuilding firms have taken out licenses to manufacture steam tnr- i bines on the Parsons. Curtis, and other systems. Professor liippcr mentioned that Messrs John Brown and Co., who deliver the Cannania. the largest turbine vessel afloat, to tho Cunard Company this week, have in hand turbine machinery of about 70,000 horse-power for tlie new giant Cunarder they are building. The Wallsend Slip Company are also making turbine machinery of 70,000 horse-power for tho sister-chip. Tho turbine appears likely to supersede the reciprocating engine tor high-power units, particularly where there is a good supply of condensing water. For marine work tho lower limit is fixed at about 0000 horeo-power, below which it is not likely at present that tho turbine will bo so successful. The cause of tho difficulty is with tho screw propeller efficiency. For electrical work a lower limit of power is available for the successful iim* of tho turbine. Up to 1000 horse-power for stationery work and 0000 horse-power for marine work, the reciprocating engine still holds the I field for economy in steam production. - I The direction in which progress has been I made in reciprocating engine work has been in the increasing uso of superheater tubes. In marine work elaborate care is taken to treat the condensed steam from tho air-pump so as to separate tho grease from it. and send the water forward as froo as possible from grease to the boilers. To such an extent has this been carried that regulations have been made in the navy and by various steamship companies to prohibit the use of oil in tho steam engine cylinders, and in rasmy cases this regulation lias been the cause of considerable trouble. Grinding has taken place between tho piston rings and cylinder surface, fine dust has accumiilaUnf, which has gone down into tho stalling boxes among tho metallic packing rings, valve faces have been scored. ; and iron dust has been found in the feed I water filter. It is. therefore, in these directions that the turbine may bo ex-' pected to show a still further advance upon tho performance of tho reciprocating engine, provided always that tho turbine is situated near a good supply of condensing water. Tho exhaust from tho turbine when condensed provides an absolutely pure feed water for the boilers, and consequently elaborate food-water purifying and filtering is done away with. Superheaters attached to boilers fed- with such water are likely to cause much less trouble than where au impure feed is used; they may, therefore, bo expected to be more generally used with turbines. If we add to this that a gain of from 10 to lo per cent, is possible by tho fact that tho steam may be expanded right down to condenser pressure, it appears likely that for these practical reasons a new step is being taken in steam engine efficiency by the use of the steam tur- ’ bine and a high degree of vacuum in the condenser.