The Progress. [volume] (White Earth, Minn.) 1886-1889, 1889-06-08
A LESSON ON STEAM.
Tho Nature Of tho Force which, Drives &
Engines Of tho Country.

a LESSON ON STEAM. M
Tho Nature Of tho Force Which Drives tho
Engines Of tho Country. s.
II will begin now, and ask you what
q steam engine is?"
What's steam engine? Why, is
this machine here, that drives the mill
That s easy enough
Why does steam let into machine
drive itp Common air let into it
Wouldn' t drive 1t, would itp''
mo, sir. {
Then there must be something
about steam different from othe Z
fluids. such as air (for mir is 4 4 uid the
same as water). to ft it for motive.
powerp '' 49,. 80
81 es, sill. !,
Yell, let us see if we can find ont
what peculiarities it has. Air and
steam are just the same in one respect
they are both fuids--or flow like
fluids. and are therefore called fluid
gasses. and either one. under pressure,
would move an engine; both are
capable of expansion and contraction
in nearly equal degree, so nearly that
the laws of one govern the other,
and
Hold on. now, my friend; you are
getting too fast. You are just like all
the fellows who undertake to tell 4
man who has had no chances son 3
thing about his business. Get back.
will you, to where you started. and
tell ne why steam drives IN engine. = Z
By re ason Of its elastic force?''
.And how does it get that force?''
From, being coiled up, asst as a
spring is wound up----by hca,. Steam
is the vapor Of water. and arises from
it at all temperatures above z..ro. Yo,,
can see it any cold morning evAporat-
ing into the air from the surface Of i
pond. !" @
Well that's all right have seen
it, though didn't knowit was steam,
but since the vapor Of water IS steam,
| suppose it was. Now would that
steam drive an engine?s'
No, not at the pressure ut which it
is generated. When you see the yapor
Of water rising from !, pond it is at
the same pressure rs the atmosphere,
and has no force above atmospheric
PRESSURE; but the same vapor, con-
tinued in boiler. and compress led by
the constant addition of more vapor.
generated by heat. will increase to any
required pressure. 81
''Ihen all there is about steam IS
that it is the vapor Of water, ana
gets its elasticity from being confined
in close vessel like q steam boiler,
is that it:?'''5=
THAT is the exact fact. Steam at
the pressure of The atmosphere is pre-
cisely the same as steam at $50
pounds per square inch; only differing
in the intensity Of the force. If you
let steam of 100 pounds down to at
mospheric pressue again. you see it
is the same old thing, and if con-
aensed, it finally becomes the water
it was generated FROM s -.58
'Ain't steam some kind Of 4 gas
that will explode iftouched off ut high
pressnrep' S.
mo; the water Of which the steam
is made consists of two gases, oxygen
and hydrogen, and the steam itself is
just the same. Now these. gases can
be divided rs you would say, or sapa-
rated again BY destroying the sleam;1
that is by forcing it through a tube.
heated white hot. The oxygen likes
the hot iron better than It does the
hydrogen, and goes for it while tho
hydrog glad to get rid If the
oxy gen goes on by itself Now, il
these two gases, oxygen and hydrogen.
are brought together in a staut re-
ceiveE III certain roportions.t they can
be ignited and exploded by an
electric spark, and their union results
III water, but to explode either Of the
gases alone requires q certain amount
Of common air to be mixed will, them,
and this isnot found in Il stean boiler.
That's what you mean. I suppose, by
steam turning into gas, is il notpn'
ell yes; I read somewhere that q
boiler blew up once because the steam,
was red hot, and turned into gas. and
I was kinder Interested in that part Of
your story, for I sometimes get this
old kettle pretty hot myself. and i
wanted to know if there was any
truth in it. = B
There isn't the slightcs- Under
the conditions under which steam IS
used in q steam boiler. it might ret
even red hot, and there would be no
danger whatever. nnlcss there was
sufficient surface Of red hot iron to
absorb the oxy gen, and atmospheric
air admitted in sufficient bulk o dilute
the hydrogen TO the explosive point.
That's a cross roads notion If the
cause Of steam boiler OK plosions.
which You must pay no attention to
whatever. All you've gotslo do is to
keep scant three gauges Of water III
that boiler; keep the safety valve in
good order, and so ahead. 1iilti,,q
Engineer.
A lscl, -, IL.