The Abbeville press and banner. [volume] (Abbeville, S.C.) 1869-1924, 1899-01-04
TOUGH ENGINEERING PROBLEMS.
They Have to Do With an Australian
Pine Line 32s Miles Long. ....

Pipe Line 1873 Miles Long.
The Coolgardie project proposes the
deliverance of 100000 gallons of
water per day at pointin the mining
regions of Australia, 1913 miles from
the reservoir in the mountains near
the coast, where it is impounded. To
force water through pipe line for
this long distance not only must its
friction be overcome, but it has to be
actually raised total vertical dis
tance of 1880 feet. Further, the dis
trict through which the pipe line
passes is desert whose soil is i'm
pregnated with salts, which are said
to be so corrosive with iron that it is
deemed safest not to bury the pipe in
the ground at all.
Another reason for having it e1.
posed is that in pipe line of such
great length>avoidance of leaks is es-
sential. If an ordinary pipe line leaks
thousandth part of its flow in mile;
the loss may be triAing matter; yet
even 80 small loss in pipe line Of
this length would amount to nearly
third of this flow. In the arid desert
through which this pipe line will pass
it is thought that the soil might alb
sorb small leaks so that they would
not show at all on the surface of the
ground if. the pipe were buried.
Facility of the inspection, therefore,
is another important reason for keep
ing 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 in winter-do not obtain at
all in the region over which this pipe
line will pass; and as the cost of ex-,
cayating and back filling trench 32S
miles long will be saved by placing
the pipe on the surface, the decision
not to bury it seems, on the whole, a
wise one. $50
The one great difficulty which is in
volved in keeping the pipe on the sur
face is the necessity of providing for
expansion and contraction. In an
ordinary continuous steel conduit,
buried in the earth in temperate
climate, the extremes of temperature
Of the water passing through it will
probably not exceed thirty; five de-
grees.
Turning now to the Coolgardie con.
duit, to be laid unprotected on the
surface of the ground, and with dis
tance between pumping stations as
great as seventy five or eighty miles,
it is evident that the water confined
from evaporation and exposed in q
steel trap to the fierce rays of the
Australian sun may reach very high
temperature in its passage from one
pumping station to the next. which in
the case of the longest conduits will
require nearly three days. The Eng
lish engineers estimate the range of
temp srature which will occur in the
pipe line a. seventy-five degrees, and
we should think this rather an under
estimate. It will be seen at once
that with such O range of temperature
internal strains would be set up in
the pipe which might become so great
as to cause movements and leakage at
the circumferential joints. Z"
Expansion joints are. therefore, es.
sential to the safety Of the pipe, and
the English engineers propose that
such joins shall be placed at intervals
of about 12O feet for the whole length
of the conduit, which would make a
total of about 5000 expansion joints
in the length of the conduit.
The engineering problem presented
then, and one which we need hardly
say is without precedent, is the de-
sign of an expansion joint for o pipe
from twenty-six to thirty-one inches
diameter, which shall provide for q
motion reaching fye.eighths of an
inch, which shall sustain pressure
reaching 200 pounds per square inch,
which shall be and remain tight, with
little or no attention, and which shall
be as nearly as possible permanent
part of the pipe line. =.