Engineering Wonders of the World
Volume III
Forfatter: Archibald Williams
År: 1945
Serie: Engineering Wonders of the World
Forlag: Thomas Nelson and Sons
Sted: London, Edinburgh, Dublin and New York
Sider: 407
UDK: 600 eng- gl
With 424 Illustrations, Maps, and Diagrams
Søgning i bogen
Den bedste måde at søge i bogen er ved at downloade PDF'en og søge i den.
Derved får du fremhævet ordene visuelt direkte på billedet af siden.
Digitaliseret bog
Bogens tekst er maskinlæst, så der kan være en del fejl og mangler.
346 ENGINEERING WONDERS OF THE WORLD.
bore-hole must be very considerable—greater
than necessary merely to reach the water.
One of the disadvantages of the air lift is
that it involves excessive first cost under such
circumstances. Then again, if much of the
yield of water comes into the
Disadztases wel1 above the leveI °f the
Advantages. risinS main’ iÉ must first find
its way down the annular
space between the rising main and the bore-
hole well. This limits the outside diameter
of the main to such a size as will not unduly
restrict the downward passage of the water.
A compromise must be made to suit such a
case. To the credit of the air lift are the
following facts: That it can be worked from,
a central point at any reasonable distance ;
that a great output can be got from a bore-
hole if water be present in sufficient quantities ;
that there are no moving parts down in the
bore-hole to get out of order ; and that water
carrying sand and other abrasive substances,
which would make the use of an ordinary
pump impossible, can be dealt with.
A PRODUCTIVE WELL (AUSTRALIA).