The Virginia enterprise. [volume] (Virginia, St. Louis County, Minn.) 1893-19??, 1898-12-16
ENGINEERING PROBLEMS.
They Have to DO with an Australian
Pipeline 328 Miles Long.

Pipeline 1913 Miles Long.
The Coolgardie project proposes the de-
livery of 100000 gallons of water; per
day at point in the mining regions of
Australia, 1923 miles from the reservoir
in the mountains near the coast, where
it is impounded. To force water through
a pipeline for this long distance not only
must its friction be overcome, but it
has to be actually raised a total vertical
distance of 1880 feet. Further, the dis
trlct through which the pipeline passes is
desert whose soil is impregnated with
salts, which are said to be 50 corrosive
to iron that it is deemed safest not to
bury the pipe in the ground at all.
Another reason for having it exposed
is that in a pipeline of such great length
avoidance of leaks is essential. If an or
binary pipeline leaks thousandth part
of it's flow in mile, the loss may be a
ttrifiing matter: yet even so small loss
III pipeline of this length would amount
to nearly third of it's flow. In the arid
desert through which this pipeline will
pass it is thought that the soil might
absorb small leaks so that they would
not show at all on the surface of the
ground if the pipe We're buried. Facility
OF inspection, therefore, is another i'm
portant reason for keeping the pipe above
ground instead of burying it.
BESIDES this, the ordinary reasons for
burying water pipes-to get them out of
the way and to keep them from freezing
Ill Wlnter-do not obtain at all in the re-
glon over which this pipeline will pass;
ana as the cost of excavating and back
tlling 4 trench 1923 miles long will he
saved by placing the pipe 7on-the surface,
the decision not to bury it seems. on the
Whole, wise one.
The one great difficulty which is H.
volyed in keeping the pipe on the surface
IS the necessity of providing for exnan-
sion and contraction. In an ordinary con-
tlnuous steel conduit, buried in the earth
IN temperate climate, the extremes of
temperature of the water passing through
IT will probably not exceed 35 degrees.
turning now to the Coolgardie conduit.
to be laid unprotected on the surface of
the ground, and with a distance between
pumping stations as great as seventy-fiyc
or eighty miles, it is evident that the wa
ter ctnhAed from evaporation and ex-
posed in a steel pipe to the fierce rays of
the Australian sun may reach 4 very hiri,
temperature in its passage from one
pumping station to the next, which in the
case of the longest conduits will reunirc
nearly three days. The English engineers
estimate the range of temperature which
Will occur in the pipeline at seventy five
degrees, and we should think this rather
an under estimate. 1t will be seen at
once that with such a range ofSStempera-
ture internal strains would be set up in
the pipe which, might become sosgreat as
to cause movement and leakage at the
circumferential joints. ~ ~
Expansion joints are, therefore. essen
tial to the safety Of the pipe. and the
English engineers propose that such
joints shall be placed at intervals of
about 12O feet for the whole length of
the conduit, which would make total of
about 5000 expansion joints in the
length of the conduit. 70 >1.%.r.t*
The engineering problem presented
then, and one which we need hardly say
is without precedent, is the design Of an
expansion joint for pipe of from 26 to
81 inches diameter, which shall provide
for a motion reaching five-eighths of an
inch, which shall sustain pressure reach
ing 200 pounds per square inch, which
shall be and remain tight, with little or
no attention, and which shall be as near,
" as possible a permanent part OF. the
pipeline. %S s.. IA, s$S5 4