All About Engines
Forfatter: Edward Cressy
År: 1918
Forlag: Cassell and Company, LTD
Sted: London, New York, Toronto and Melbourne
Sider: 352
UDK: 621 1
With a coloured Frontispiece, and 182 halftone Illustrations and Diagrams.
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Steam Turbines 175
feet wide, large enough for a crowd of men or a motor-
car to pass through with ease.
This condenser has a surface of 39,300 square
feet, and is built of steel plates, with all the stiffen-
ing girders on the outside in order to avoid inter-
rupting the free flow of steam. The tubes are 1 inch
in external diameter. This is rather larger than is
usual, but there is less danger of them becoming
choked by deposit than with smaller tubes. They
are arranged in two “ nests,” one in the upper part
and one in the lower part of the casing.
The circulating water enters the lower compartment
through a rectangular opening, 5 feet 9 inches by
2 feet 2 inches, and after passing through both
compartments flows out through a tube 4 feet in
diameter.
Exhaust, Reducing, and Back-pressure Turbines
So much for high-pressure turbines. An addi-
tional merit of this form of prime mover lies in the
fact that it is very efficient with a low pressure of
steam.
There are no narrow ports as in the ordinary
reciprocating engine, except at the point where steam
is admitted, and the steam passes through open-
ings of gradually increasing size on its way to the
condenser.
The power that is obtained by increasing the
vacuum in the condenser from 28 inches to 29 inches
is greater than that obtained between 27 inches and
28 inches. Consequently, with a good air pump