All About Engines

CHAPTER V The Modern Reciprocating Engine1 IN the first chapter we took a simple engine to pieces, as it were, found out what each part was like, why it was there, and what purpose it served. For its size it was a good engine. Fed by steam of low pressure, it worked well and used as little fuel as could be expected. In the meantime, however, we have become acquainted with boilers that will produce steam at 160 lb. or anything up to 200 lb. on the square inch, at the rate of 30,000 or 40,000 lb. an hour, and we have realised that there may be not one, but ten or twenty boilers of this size in a modern power station, so that there must be engines of corresponding size to use up the steam they produce. It is necessary, moreover, that they should be capable of extracting the greatest possible amount of the energy con- veyed to them by the steam. For they will be large engines, mostly, and their annual coal bill will repre- sent a small fortune. A man who only burns 20 tons of coal a week doesn’t always bother much about the £2 or so a week that a 10 per cent, increase of 1 Reciprocating means •• forwards and backwards,” and the name reciprocating engine is given to one which has a piston working forwards and backwards in a cylinder. 105