Frostburg mining journal. [volume] (Frostburg, Md.) 1871-1913, 1871-12-30
For the Frostburg Mining Journal.
Philosophy Of Steam Boiler Explosions
By n. @. RYAN, OF borden sHAYr.

BIZ n. @. RYAN, OF BORDEN SHAFT.
Steam boiler explosions have sent many
thousands of our most noble and generous
hearted fellow men to early graves. They
have brought unexpected sorrow and pow
erty to the homes of many happy and pros
porous families Terrible have been the
heart-rendng results OF these disasters,
and yet We are promised no better protec
| ton against them in the future. Scientific
men are always prepared to give the causes
Of explosions, but, as yet, have failed to
furnish means by which they may be
prevented.
Boilers, made OF good metal and Of sufti-
cient strength, provided with good safety.
valve, controlled by q competent engineer,
have been offered by some as being suffi-
cient protection. All this may seem very
plausible, and is, to great extent, correct !;
but who is to satisfy the public when such
provision has been made. Good boilers,
provided with reliable safety valve, can
be proved as such without the introduce
ton Of steam, or the risk of an explosion !;
but competent engineer is not 30 readily
tested He may pass as competent before
one board Of examiners and fail to pass as
such before another. He may be even bet
ter qualified to take charge of an engine
than the examining party, and yet be no
security against explosions. True, lie may
guard against everything which might, in
his judgement have any tendency towards
producing an explosion. This is saying all
for him that can be said; but in this case
the public safety would depend upon what
he believed would cause, or prevent, an
explosion, and, as there have been many
and contradictory reasons assigned for
| them, it has become almost impossible for
the public to rely very much upon any of
them in consequence.
will lay before the public the follow
ing facts, which hope will receive care
full attention:
1t has been noticed that explosions gen.
orally occur while the engine is standing,
or while being started, after having been
for short time at rest 1t is. therefore,
evident that something takes place when
the engine is at rest which would not &C.
cur if kept in motion. 1t is this which
will endeavor to explain:
First Water is no conductor Of heat
The only way in which it can become
heated is by circulation; that is, the layer
I.>r, 4 l,> l,ntf ~ no hnsloe
posed to the heat of the furnace, becomes
heated. and consequently, lighter. 1t pass
es up and makes room for another layer
| to find its way to the source Of heat, when
it becomes heated and passes up in its turn.
Thus the circuit is continued until all the
water in the boiler becomes heated, or as
| long a. the fire 10 kept up in the furnace.
Second. II, by some means. the water in
! the boiler was made to cease circulation.
and the fire continued in the furnace, the
! motal would absorb all the heat, and con-
t:nue to absorb it, until it was melted,
without disturbing the temperature Of the
water.
Third II, while the metal was thus
heated to . high degree or red heat. the
water was suddenly put in motion. or
brought in contact with the heated, surface,
the generation Of steam would be 30 sud
den. and the quantity 20 great, that it
would, while endeavoring to escape, break
the strongest boiler, no matter how relja-
bic the safety-valve might be for practi-
cal use.
Fourth. BY keeping the water in the
boiler in circulation, or by keeping the en-
| CINE in motion, the metal, or water, would
not become any hotter, nor the steam pres
| sure any higher, than that indicated by the
steam-gauge. a. by the steam-gauge We
know the temperature a. well a. the densi-
ty Of the steam, thereby enabling an engi-
nesr to know what i going ON inside the
boiler.
| F1A II an engine be suddenly brosght
to state Of rest, and tho steam pressure
being comparatively low and the wstes
above the low-water-mark. there 10 just, or
Aearly - much danger Of The metal becom-
ing heated to high degree a. il the wa
ter was low and the steam pressure high
as fifteen pounds pressure to the square
inch contains precisely the same amount
of heat as is contained in q pressure OF
| three hundred and fifty pounds to the same
! surface.
Sixth. Steam contains about 1000 degrees
Of heat which the thermometer does not
indicate; according to Fahrenheit's scale)
that is, when the thermometer indicates
212 dsgs. there are 1000 dogs. more which
are not indicated. This 1000 dogs. is called
the latent, or insensible, heat of steam. and
212 degs. less 50 dogs, Che number Of de-
grees from zero to the boiling point tie
sensible heat. Just in proportion to the
increase of the sensible heat, the latent, or
insensible, heat diminishes, making the
sensible and insensible always the same
about 1900 dogs.
Seventh. Steam, by being pressed or cor i.
densed, suffers its latent heat to escape
Thus it is evident that when an engine ia
suddenly checked, or brought to stand,
the pressure in the boiler becomes suddenly
very great, and, If the fire be damped down,
the steam will proceed to condensc; in
both cases changing its latent heat into