The Forest Republican. [volume] (Tionesta, Pa.) 1869-1952, 1877-04-11

is increased beyond the strength of
the boiler, and the rupture or break
will commence at the weakest part Of
the boiler; the violence Of the explo-
sion will depend npon the pressure at
the time, aud, upon the point as
regards the water level at which the
boiler yields" Such explosions (and
I take it from what I hear that the
explosion at Rogers & Landers mill
was Of this class. when they occur in
cases properly constructed boilers,
can only be produced by pressure
very much above tho ordinary work
ing pressure and, may DO pro.
ddced By an accidental or willful
overlooking Of the salty valve by the
adhesion OF the valve 10 i;s seat; or
by the closing Of a stop valve between
the safety valve and the boiler. Many
accidents have occurred from defect
i've safety valves. Hcsays as bearing
upon this part of the subject Of the
strength Of boilers to withstand
steady pressure 1T will not be out
of place to mention the case Of an old
boiler which | tested some years ago:
this was forty.two inches in diameter,
about twenty eight feet long, with two
twelve.inch hues through it. The
heads were of cast iron. The iron in
the shell appeared to have been 516
of an inch in thickness, and that in
the 1ues SIG of all inch thick. II had
been in use for over twenty years. and
it was known that the water had been
so low in it at one time rs to lead to
supposition that it might have been Sc
verely injured by the over heating. 1t
had also heavy ind4ntation on its
lower side, caused by settling Of the
front, thereby bringing too much
weight on little pier on the brige
wall yet ii stood a pressure of two
hundred and forty pounds per square
inch without sign Of yielding. Not
withstanding this great strength Of
boilers, it is undoubtedly trua that
there have been explosions of boilers
>at their ordinary working pressures,
without overheating and without sud-
den increase Of pressure, because Of
defects of material, design or work.
manship; as, far example, a plate that
has to be nanged, may be so poor, or
worked with so little skill as to have
so little strength left in the bends that
Il little alteration Of form, from varia.
tion Of pressure, on account of the de-
fective staying Of the fiat part Of the
plate, may lead to an explosion. A
boiler may be SO poorly stayed that
very little corrosion arouDd an inrper-
feet weld in one of the stays may lead
to an explosion; or plate may have
it's strength so reduced at or near
longitudinal seam in punching, bending
pinning, and riyeting, that the little
alteration of form that takes place at
this place at every variation of press
ure, may, by corrosion, so reduce the
plate in strength at that point, that an
explosion may ensue."
l know 10 part Of mill that
needs SO much care as the boiler, and
yet gets so little, and therefore it is no
wonder that about every paper you
read the first thing that meets your
eye, is, "a Boiler Gone Up" l think
we have as good men handling boilers
in this region as anywhere in the Uni
ted States, but the trouble is, as long
MS boilerwill run, why let her run,
and it is never replaced or laid aside
until it has burst itself and some one
With it. II.