The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1899-01-22
TOUGH ENGINEERING PROBLEMS.
They Have to Do with an Australian
Pipeline BPS Miles Long.
Engineering News

The Coolgardie project proposes the deliv
cry of 100000 gallons of water per DAY at
a point in the mining regions OF Australia
1913 miles from the reservoir in the noun
tainS near the coast where 1t Is tmpounded.
To force water through a pipe lne lot TINS
long distance not only must its friction De
overcome, but it has to be actually raised
a total vertical distance of 1850 feet. Fur
Their the district through which the pipe
line passes is a desert whose soil is impreg-
mated with salts, which are said to be so
corrosive to iron that 1t is deemed safest
not to bury the pipe in the ground at all.
Another reason for having it exposed IS
that in pipe line of such great length
avoidance of leaks is essential. If an ordl-
nary pipe line leaks thousandth part or
it's flow in mile the loss may be a tr1f1ing
matter; yet even so small a loss in pipe
line of this length would amount to nearly
through which this pipe line 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
were buried. Facility of inspection, there
FORE is another important reason for keep
ing the pipe above ground instead of bury
ing it.
Besides this, the ordinary reasons for
burying water pipes-to get them out of the
way and to keep them from freezing in win
ter-do not obtain at all in the region over
which this pipe line will pass and as the
cost of excavating and back filling a 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.
The one great difficulty which is involved
IN keeping the pipe OH the SuI1dCG 10 INC
necessity for providing for expansion and
contraction. In an ordinary continuous
steel conduit buried in the earth in a tenn
perate climate, the extremes of temperature
of the water passing through 1t Will prob
ably not exceed So degrees.
Turning now to the CoOlgardie conduit
to be laid unprotected on the surface of the
ground, and with a distance between pump
ing stations as great as seventy-ffve or
eighty miles, it is evident that the water
confined from evaporation and exposed in
steel pipe to the fierce rays of the Austria
liam sun may reach a very high temperature
in it's passage from one pumping station 10
the next, which IN the case of the longest
conduits will require nearly three days. The
English engineers estimate the range or
Temperature which will occur in the pipe
line at seventy degrees and we should think
this rather an underestimate. 1t Will be
seen at once that with such range of tenn
perature internal strains would be set up in
the pipe which might become so great as to
cause movement and leakage at the circum-
ferential joints.
Expansion joints are, therefore. essential
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 a total of about 10 900 expansion joints
in the length of the conduit.
The engineering problem presented then,
and one which we need hardly say is with
out precedent, is the design of an expansion
Joint for a pipe Of from twenty-siX to thlr-
ty-one inches in diameter, which shall pro-
vide for motion reaching five-eighths of
ing 200 pounds per square inch, which shall
be and remain tight, with little or no atten-
ton and which shall be as nearly as pos
sible a permanent part of the pipe line.