The Virginia enterprise. [volume] (Virginia, St. Louis County, Minn.) 1893-19??, 1902-03-07
WHY BOILERS EXPLODE.
An Old Engineer Gives the Result of
His Experience.

An OAO Engineer OlHeS the ReSult OIL
His Experience.
"Why do boilers burst?'' repeated an
old engineer. Of whom the question was
| asked. 'Well. boilers are like people,
i'll that when they are ill-treated they get
red-hot and explode.
THE principal cause Of explosions is
because Of insufficient water in the boiler.
The water must be kept above the tubes,
so that it may boil freely. When it falls
below the tubes the boiler becomes red
hot, the steel plates soften, expand and
crack, and, swish, up she goes, and all
else in the immediate vicinity.
'Ile number Of boiler explosions in
different parts Of the country lately calls
to mind the constant menace to human
life and property existing literally under
our very feet, as it is in easements and
under the sidewalks where most Of the
boilers are situated. The great wonder
is that more do not go up in the air, incl
contents or the sidewalk with them. l
saw the wreckage caused by the fatal
boiler explosion in Pittsburg recently.
The building was completely demolished,
and the ruins looked as though the build
ing had been blown to pieces and the
ground leveled by dynamite.
Boilers also burst where they have
flaws and unseen defects in the metal
which will not stand the strain of the
pressure of the steam. and the plates
part at this particular spot. Inspections
often fail to reveal these flaws, with ter
rible results. Cold water let into the
boiler when it is hot ana wnen there is
ell means an explosion. The steam is
generated SO rapidly, and it's force is so
terrific, that the plates part like pieces
of paper. In the iron region the sulphur
in the water used has eaten the bolts off
boilers l have attended inside of three
months, and great care as to their re-
pair in season has to be exercised. Scales
will also form on the tubes, and when
thickened SO that the steel becomes red
hot at this point, but the water cannot
get tC the metal because of the scale,
these 'blisters part and an explosion re-
suits.
lin some of the big department build
ings in Washington the boilers are fired
to only about one-sixth of their tensile
strength, and boilers with a licensed ca
pacity of withstanding 12O pounds Of
steam pressure to the square inch carry
only from ninety to 100 pounds, the safe
ty valves being set at the latter figure.
When the safety valves work all right a
vent for the danger pressure is permit
ted, but when they don't, as is sometimes
the case-well, you will learn all about
it when you wake up the next minute III
the other world.
"Boilers are better made now than
formerly, and are constructed of steel
instead Of iron, as long ago. The boiler
steel is tested to withstand a tensile
strain of 10000 pounds to the square
inch, as against 10000 pounds of a gen.
Grafton ago. Boiler explosions, while fire.
quent enough now, do not compare in
number as at that period. There is a
more perfect system of inspection and a
better class of men in charge, who are
required to pass an examination and re-
ceiye licenses before they are allowed to
run stationary engines. as my remarks
do not apply to the boilers Of locomo-
tiycS'