The Sun.
London, England, 1870-06-02 00:00:00

A NEW MOTIVE POWER.

Mr. Galloway, who has for many years devoted his
attention to the problem of how to generate steam quickly
anct inexpensively, now comes forward claiming to have
found the solution. He has invented an apparatus, the
design of which is, riot to supersede the existing steam
boilers, but to be affixed to them, its operation saving 50
per cent. in the cost of fuel. The invention consists
in the application of atmospheric air, which
is first of all pumped down a pipe passing
through the flue, the air being heated on its passage ;
the pipe is continued under the furnace, and passing
through returns on the back under the fire bars ; and the
temperature of the air having thus become raised by the
waste heat is driven into the boiler, and helps to generate
steam in the chamber, the action of the piston rod assist-
ing the process. Whilst shewing his invention to some
savans the other day, Mr. Galloway entered into an ex-
planation. He said :—The use of atmospheric air,in com-
bination with steam, would seem to possess peculiar advan-
tages, inasmuch as atmospheric air, as soon as it is com-
pressed, gives out latent heat by the mere application of
pressure. At a meeting of the Iron and Steel Institute,
held a few days since, this question was asked—
" Whether combustion under pressure itself gave out
greatly increased heat ?" Mr. Fothergill adding, " Sup-
posing the pressure of the atmosphere were, say 301 b. on
the square inch, instead of 151 b., the usual pressure ?"
To this Mr. Siemens, who is an acknowledged autho-
rity, replied, that in that case the temperature of the
atmosphere would be raised to 210 deg., taking the
original temperature at 60 deg. This would seem to
prove that atmospheric air, if compressed before
combustion, and afterwards allowed to enter into
combustion under pressure, will produce greatly
increased heat. And this result, I submit, takes
place in respect to the use of heated air, which
may be said to be in a state of combustion, in the arrange-
ment of the air pipes which you see before you. Respect-
ing the uses to which this invention may be applied,
and which I have contemplated in my patent, let me say
that the great advantage is that it is not so much a sub-
stitution for the steam engine as a simple improvement
that may be applied at a trifling cost to all kinds of en-
gines, whether marine, locomotive, or stationary ; and
there are ulterior advantages which may not at first sight
appear. First, though it may seem to be somewhat in-
significant, I hope that we may live to see the day when
the necessity for horses drawing ponderous loads along the
streets and roads will be pretty nearly, if not altogether
obviated ; one beneficial result of which would be that a
larger area of land would be left for the cultivation of
food for mankind ; and in the case of the streets the
noxious vapours and nuisances inimical to health would
be prevented by the substitution of air and steam for
horse power. But there is another application of the in-
vention also contemplated, and to which I recently re-
ferred at a meeting of the members of the Institute of
Naval Architects, in the presence of Sir John Pakington
and other distinguished gentlemen, viz., its application as
an auxiliary power to sailing vessels, requiring as it does
less than half the ordinary room and stowage of fuel for
the generation of the motive power, in connection with the
fact that it will save upwards of sixty per cent of fuel; I
trust to get it up to seventy-five per cent. This will be of
the utmost importance to shipowners, as it will greatly
increase the value and efficiency of their sailing ships.
and render them almost equal to screw steamers.
Referring again to the properties of compressed
air and its immediate application to this inven-
tion, the results may be expressed as follows :
Assuming that by the circuitous mode by which the air
after it has left the air-pump, traverses along, you will
have observed that the air passes ' through the iron pipe
along the flue, and is then conveyed in continuation
beneath the furnace bars through the fire bridge, and re-
turns by the other side of the furnace. You will probably
have felt on touching the branch pipe that the heat was so
intense that you were unable to bear your hand upon it
for a moment. This intense heat, which otherwise would
all have been wasted, may probably be estimated at say
about 100 degs. Should this be so, then two-thirds of
the heat contained in the air will have been given off
through the water in the boiler, and will have generated
steam equivalent to what is generally called three steam
pressures, 220 degs. being the estimate for the genera-
tion of steam. Assuming this formula to be correct, it
follows as a necessary result that a saving of three-fourths
pro-rata of the cost of fuel by my plan must have been
effected by what I may be permitted to call liquid fire
forced in and through the water.