FULL STEAM AHEAD!

Hawke's Bay Herald-Tribune, Issue 65, 3 April 1937, Page 11

FULL STEAM AHEAD!

The Prime Mover in Industry *

gTEAM is still by overwhelming odds tbe prime mover in industry. So great is tbe resistance of copper wire to tbe long-distance transmission of electricity tbat it is cheaper to buy coal to xoduce a kilowatt than to transmit a kilowatt over 300 miles from the place wbere. it.is made, statcs George Gray in tbe January Atlantlc MontbTy. Coal can be sbipped from five to ten times tbe diistance tbat electricity can for tbe same cost. Tbe economy of fuel utilisation bas not only been tripled in tbe past fiftcen years, biit tbe steani that men are'extracting from eacb ton of coal can give more tban double the output of electricity tbat it did in 1920. • Niagara 's water wbeels are already 90 per cent efficient. Tbe present eflBciencv of steam is between 25 and 3!j per cent and it can compete successfully witb water power efficiency al- ' xeady, so isn't it natural tbat tbe possibilities of steam should continue to fjgy.alft tbe imagination of inventors and industrialistsf Tbe principle of beat conservation ia the key to all our gains in modern steam power efficiency. To generate tbe entering steam in, a turbine at a temperature as high as it ia possible to control, is tbe aim. In a modern turbine as tbe hot vapour " bombards tbe spinning vanes of tbe atainless steel xotors at 925 degrees P. and a pressure of 1,200 pounds to tbe •quare incb, tbe vanes literally extract

beat from tbe cleverly directed burrlcane of steam. So great is tbe superheat that tbe metal glows dull red. shines in tbe dark. Eacb stage of tbe .whirling mechanism is larger, expands the steam more, until the spen vapour at the end of its journey rushes into the condenser 's vacuum at 80 degrees, so chill as to cool the handl Ten tonts of water and 12 tons of air must go into the boiler and the eombustion chamber to get the maximum beat of steam from a ton of coal. Ten steam plants on the sbores of the Hndson Biver bave xaised New York's East Biver 's temperature 'sixteen degrees in tbe last tbirty years. Distilied wate* is used in tbe boilers. and conserved and re-used. Powdercd coal and p.rebeated air make possible tbe generation of temperatures as bigb as 3.0 00 degrees. The layman 's thought of steam is associated with bubbling water. Mercury, the familiar liquia metal quicksilver, boils,at 677 degrees rather than at tb» 212 degrees necessary for water. Tbus, when vaporised, the mercury vapour can turn a turbine, and tbe still-bot excess can be used to evaporate water to steam and turn anotber turbine, two instead of one. Dipbenyl oxide, wbicb boils at 596 degrees is also being invea'tigated. • Tbe story of steam power 's recent advance is primarily a story of increasing teinperatures and mounting pressures. Engineers never say "nover 7"