Evening star., 1899-02-04
ENORMOUS PIPE LINE.
An Australian Conduit Over Three
Hundred Miles Long.

From the Engineering News.
The Coolgardie project proposes the de-
livery of 5000 900 gallons of water per day
at point in the mining regions of Aus
trala. 32S miles from the reservoir in the
mountains near the coast, where it is i'm
pounded. To force water through a pipe
line for this long distance, not only must
its friction be overcome, but it has to be
actually raised total vertical distance of
1880 feet. Further, the district through
which the pipe line passes is a desert whose
soil is inpregnated with salts, which are
said to be so 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 pipe line of such great length
avoidance of leaks is essential. If an or
dinary pipe line leaks thousandth part of
its flow in mile, the loss may be a trifling
matter; yet even so small a loss in pipe
line of this length would amount to nearly
a third of it's flow. In the arid desert
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 il.
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 eXcavating and back filling a
trench 32S miles long viii be saved by plac-
ing the pipe on the surface, the decision NOT
to bury 1t seems, on the whole a wise one
The one great difficulty which is involved
in keeping the pipe on the surface is the
necessity of providing for expansion and
contraction. In an ordinary continuous
steel conduit, buried in the Garth in a tenn
perate climate, the extremes of tempera-
ture of the water passing through it will
probably not exceed SO degrees.
turning now to the Coolgardie conduit, to
be laid unprotected on the surface of the
ground and with distance between pumn-
ing stations as great as seventy-fve TO
eighty miles, it is evident that the water
COnflned from evaporation and eXpoSed in a
steel pipe to the fierce rays of the Austra
nan sun may reach Il very high tempera-
ture IN IT'S passage from one pumping sta
| tlon to the next, which, in the case of the
| longest condults, VIII require nearly three
! days The English engineers estimate the
| range OF temperature which will occur in
| the pipe line at 10 degrees, and we should
| think this rather underestimate. 1t will
| De seen at once that with such a range of
| temperature internal strains would he SET
| up IN the pipe which might become so
| at the circumferential joints
Expansion joints are, therefore, essential
| 10 the safety OF the pipe, and the English
| engineers propose that such joints shall be
| placed at intervals of about 100 feet for tho
! whole length of the conduit. which wound
| make a total of about Is 900 expansion
| joints in the length of the conduit
The engineering problem presented then
| tand one which We need hardly say is with
| out precedent is the design of an expansion
4 JOINT Tor a pipe of twenty-siX to thirty-one
| inches diameter. which shall provide for a
| motion reaching five-eighths of an inch.
| which shall sustain pressures reaching 200
| pounds per square inch. which shall be and
| remain tight, with tile or no attention.
and which shall be as nearly as possible a
| permanent part of the pipe line.