Phenix gazette. [volume] (Alexandria [D.C.]) 1825-1833, 1832-08-31
EXPLOSION OF STEAM BOILERS.


The following remarks on the causes OF these
explosions. are by Mr.. Jacob Perkins, gentleman
who has devoted almost the whole Of his life to the
study of the nature and properties Of steam
sit appears to be wel-established fact, that
the calorc of steam, st given density, is con-
slant quantity when in contact with water This
is undoubtedly the case, if the steam is properly
generated; but If any part of the boiler, which
contains the steam. is sufferedito get at higher
,emperature than the water contained in it, IRON
want Of sufficient supply of water. the steam
will receive an excess of caloric, and become SUI
Dersa,urated steam, without adding any available
power thereto. In some recent experiments, have
heated steam to temperature (viZ. l2O0)that
would have sivin to it all the power which steam
is calpable eyertins wiz. nearly 0.O00bs to the
square inch, if ii had had its full quantum Of wa
ter. Yet the Indicator showed pressure ofless
than five atmospheres Having satisfied myself,
by repeated experiments, as to the certainty oil
this curious fact. ille thought struck me that. If
heated water ives injected suddenly into this
mass Of supersaturated steam. the effect would
be instantly to form highly elastic steam-the
strength of which wonld depend upon the tenn
perature of the supersaturated steam, and the
temperature and quantity OF water injected 10
ascertain the trutn 0t tnis leoiN. "aoe pe wv
lowing experiments:
The generator was filed with water, and heat
ed to about 500 degrees. The pressure valve
being loaded at 20 atmospheres. 1t prevented the
water from expanding into steam. The receiver.
which was destitute Of both water aud steam, be-
mo heated to about 1900 degrees, small quan-
tty of water was injected into the generator with
the fnrcinp pump, which forced out from under
prcssure valve of the generator. into the rcceiv-
er. a corresponding quantity; and this instantly
flashed into steam; which, from its having lgnit-
eel the hemp that covered the steam-p'pe ten feet
from the generator. must have been alta tempera-
ture of at least 500 degrees; but from want OF wa
ter n olive it us necessary density, the Indicator
showed pressure of only about hive atmospheres'
Whether the pressure OF the steam which was
rushing through the steam pipe. vas at hve or one
hundred atmospheres. the steau-plpc kept up at
the high temperature before mentioned; undoubt
edy, owing to the steam being snpersaturateu
with caoric. The pump was now made to inject
much larger quantity of heated water; and the
Indicator, in an instant, showed pressure OF
from so to 60 atmospheres. 1t soon expanded
| 1.-THE throttle-vave being partially opened) to the
| former pressure Of about FIVE atmospheres. The
water was injected again; and again the indicator
was observed to osciatc, at each stroke OF the
pump, from to 40 and 100 atmospheres, accord
ING to the quantity of water injected-clearly
showing that, at the reduced pressure, there was
a great redundance and loss of heat, with little
elastic force. 1t soon occurred to me, that here
may be traced the true cause Of the tremendous