THE STEAM TURBINE.

Progress, Volume I, Issue 12, 1 October 1906, Page 343

THE STEAM TURBINE.

By the Hon. C. A. Parsons, C.8., F.R.S

The introduction of the turbine commenced in 1884 with a 10 horse-power turbine and dynamo. The system adopted in 1884 was that of causing the steam to pass through a large number of turbines in series suitably proportioned, so as to utilise the expansion of the steam which flowed at a comparatively moderate velocity because of its circuitous course through the many turbines of the

series, just as is the case with water flowing through a long course of rapids from the lake of high level to one of lower level, the lake of high level corresponding to the boiler, and the one of lower level to the condenser. In the initial stages the course of procedure commenced with the construction of a few turbine engines of small size, these were carefully tested and sent out to work and closely watched by competent men. Defects were promptly remedied and improvements discovered which were adopted in new designs and resulted in gradual accumulation of experience and trade knowledge. In the first year three engines were set to work, in the next year ten, and so on, until at the end of the fifth year, three hundred and fifty had been put into successful operation, all of the non-condensing type aggregating four thousand horse power. In 1888 working plans were prepared for a turbine of the condensing type which presented hopes of realising unprecedented economy m the use of steam for motive power and a great step in the development of the turbine. It was not till 1 89 1, however, that facilities were available for its construction, and the anticipations were at length fulfilled when in the following year a hundred unit condensing turbo-generator was found to consume only twenty-seven pounds of steam per kilowatt hour, thus equalling the performance of the best triple-expansion engine of that date in the driving of dynamos. The turbine which achieved this result differed materially from that designed m 1888 because of the temporary loss of patent rights under which the work had been carried on up to this period. In 1893 the

patent rights were reacquired, this permitting of reversion to the original and parallel type, and subsequent experience has shown that had me 1888 design been constructed in its entirety in 1892 an economy would at that date have been obtained about 25 per cent, superior to that actually realised. There is now no question that the turbine in its present perfected and economicul form would in that case have come into general use about five years earlier, both for land and marine work. A simple explanation might be asked for as to why the turbine should be more economical than the reciprocating engine. The answer is that the turbine is able to expand the steam fully and economically from the boiler pressure right down

to the condenser pressure while the reciprocating engine is unable to expand it the whole way, as a matter of fact it can only expand it usefully for about two thirds of the way. This is the chief difference, the other differences nearly compensate each other, for instance, the turbine has more waste from leakage, while m the piston engine there is a large waste from condensation and re-evapora-tion which does not occur in the turbine. Then again the turbine has fluid friction from steam and water and very little mechanical friction, while the reciprocating engine has much more mechanical friction and very little fluid friction.

The Overland Monthly, published in San Francisco, has an illustration in its July issue depicting the San Francisco branch of the New Zealand Insurance Company, taken immediately after the earthquake. Under the picture it is stated that this was the first insurance company to start up on their old location in California street.