y,
of Ann Arbor, Mich., in which he says:
"The benefits of covering steam-pipes to prevent radiation are
strikingly illustrated by the following example: The Thomson-Houston
electric-light plant in Ann Arbor has about 60 feet of seven-inch pipe
connecting the boilers with the engines and two large steam-drums above
the boilers: in March, 1887, the steam at the far end of this pipe was
tested to determine the amount of entrained water, the pipes and drums
at the time being uncovered. An average of nine experiments gave 31.01
per cent moisture. In June of the same year, after the pipes were
covered with magnesia sectional-coverings, the quality of the steam was
again tested, the average of five experiments giving 3.61 per cent
moisture; the tests were made by the same men from the same connections,
and in the same manner. The pipes and steam-drums in March were
subjected to a draught, which, of course, aided the condensation. Enough
water passed into the cylinders to retard the engines, producing a
disagreeable noise. In June the weather was warmer and the pipes and
steam-drums were well protected. The quality of steam at the boilers was
tested in June, and showed about three per cent moisture. Assuming that
100 incandescent horse-power were being developed at the time, and that
each horse-power required 30 pounds of steam; if the steam is assumed to
have 25 per cent entrained water due to condensation in the pipes and
connections, then 4,000 pounds steam will need be produced in the
boilers, or 1,000 pounds more than necessary. To produce this steam will
require about 125 pounds of good coal per hour, or 1,000 pounds per day
of eight hours. One-half ton per day at $3 per ton for 300 days, $450.
The actual cost of the covering put on complete probably did not exceed
$150."
An interesting verification of the remarkable non-heat condensing
quality of the magnesia covering occurred at Lynn, Mass. In the heart of
the district in that city, recently the scene of the disastrous
conflagration, there was located the machine-shop of Messrs. Rollins &
Glozier. A two-inch steam-pipe there was covered with this material. The
heat of the fire at this place has been curiously determined to have
been between the minimum extreme of 2,756 deg. Fah. and the maximum extreme
of 2,950 deg. Fah., in this way: Cast-iron melts at 2,756 deg. Fah.;
wrought-iron at 2,950 deg. Fah. A portion of the cast-iron bed of a lathe
was fused into an irre
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