IMPROVEMENTS IN OBTAINING POWER WHEN AIR IS EMPLOYED
Year: 1853

page_text: LETTERS PATENT to Moses Poole, of the Avenue Road, Regent's
Park, in the County of Middlesex, for the Invention of "IMPROVE-
"
Sealed the 17th May 1853, and dated the 21st March 1858.
PROVISIONAL SPECIFICATION left by the said Moses Poole at the
. Office of the Commissioners of Patents, with his Petition, on the
21st March 1853.
I, MOSES POOLE, of the Avenue Road, Regent's Park, in the County
of Middlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN OBTAINING POWER WHEN AIR IS EMPLOYED" to be as
follows:-
The first improvement in air engines consists in absorbing the heat
given out when the air is compressed by the force or supply pumps now
used in such engines; this may conveniently be done by injecting water.
The second improvement in air engines consists in supplying the
heat which is absorbed when the air is expanded in the working
cylinder, either by means of a jet of fused metal injected into the

page_text: cylinder, or by means of wire cloth which is heated by being plunged
into a bath of melted metal at the bottom of the cylinder; or the air
may be heated in the passages before arriving at the working cylinder,
either by means of heated wire cloth or by a jet of fused metal.
The third improvement is applicable to close air engines, and consists
of absorbing the heat existing in the air when it has done its work
before it again enters the force pump. This may conveniently be done
by passing the air through wire cloth which is kept cool by means of a
current of air or liquid, or it may be done by means of a jet of cold
water.
The fourth improvement in air engines consists in passing the air,
when it is to be heated or cooled, through a heated or cooled grating
formed of strips or ribbons of metal, in place of passing it through
wire gauze similarly heated or cooled as has hitherto been generally
employed.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Moses Poole, in the Great Seal Patent Office, on
the 21st September 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
MOSES POOLE, of the Avenue Road, Regent's Park, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of March, in the
year of our Lord One thousand eight hundred and fifty-three, in the
sixteenth year of Her reign, did for Herself, Her heirs and successors,
give and grant unto me, the said Moses Poole, Her special licence
that I, the said Moses Poole, my executors, administrators, and assigns,
or such others as I, the said Moses Poole, my executors, administra-
tors, and assigns, should at any time agree with, and no others, from
time to time and at all times thereafter during the term therein ex-
pressed, should and lawfully might make, use, exercise, and vend, within
the United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN OBTAINING POWER

page_text: WHEN AIR IS EMPLOYED," communicated to me from abroad, upon the
condition (amongst others) that I, the said Moses Poole, by an instru-
ment in writing under my hand and seal, should particularly describe
and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Moses Poole, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof (that is to say):
The first improvement in air engines consists in absorbing the heat
given out when the air is compressed by the force or supply pumps now
used in such engines; this may conveniently be done by injecting water.
The second improvement in air engines consists in supplying the
heat which is absorbed when the air is expanded in the working
cylinder, either by means of a jet of fused metal injected into the
cylinder, or by means of wire cloth which is heated by being plunged
into a bath of melted metal at the bottom of the cylinder; or the air
may be heated in the passages before arriving at the working cylinder,
either by means of heated wire cloth or by a jet of fused metal.
The third improvement is applicable to close air engines, and consists
of absorbing the heat existing in the air when it has done its work
before it again enters the force pump. This may conveniently be done
by passing the air through wire cloth which is kept cool by means of a
current of air or liquid, or it may be done by means of a jet of cold
water.
The fourth improvement in air engines consists in passing the air,
when it is to be heated or cooled, through a heated or cooled grating
formed of strips or ribbons of metal, in place of passing it through
wire gauze similarly heated or cooled as has hitherto been generally
employed.
In order to set forth with distinctness and conciseness the design and
purpose of this Invention it is necessary to consider the general nature
of the engines or machines commonly called air engines or vapour

page_text: engines. I refer to the accompanying drawing in which Figure 1,
represents a vertical section of the chief necessary parts of an air engine.
I suppose the necessary parts of an air or vapour engine to be the
three following:-First, a force pump or other compresing part, see
drawing Figure 1, A, in which the air or vapour is mechanically
reduced in bulk; 2nd, a working cylinder B, or other expanding part in
which the air or vapour moves a piston; 3rd, a pipe or channel C, C,
connecting the compressing and expanding parts of the engine in which
apparatus D, for heating or cooling the air or vapour,
economizing the heat employed, are placed.
or apparatus for
One of the purposes of the Invention is to absorb the latent heat of
compression given out in the compressing part of the engine by the air
or vapour while undergoing diminution of bulk by mechanical pressure,
and this I effect by means of an injection of cold fluid, say water, in
the form of a jet or shower, using the well-known means, Figure 1, E, F,
of introducing and removing the same.
If this latent heat of compression be not absorbed it becomes sensible,
and increases the tension of the air so that much greater power is
required to compress it. The degree of loss or waste of power attribut
able to the heat of compression is in proportion to the quantity of
heat so evolved. If the quantity of heat so evolved were small it might
be neglected without important evil results, and, until recently, it was
supposed, according to the experiments of Dalton and other philosophers,
that the heat reduced sensible by each compression of air to half its
bulk was from 50° to 70° Fahrenheit. Were this the fact the heat of
compression might perhaps be neglected without serious evil, but it
appears from recent careful experiments of Dr. Gorrie, reported in
"Silliman's American Journal of Science and Arts," July and September
numbers, 1850, that the heat rendered sensible in air compressed from
a tension of one atmosphere to a tension of two atmospheres is 277°
Fahrenheit, a quantity of heat which cannot be neglected without dis-
advantage.
Another purpose of the Invention is to supply the heat rendered
latent by the expansion of the air in the working cylinder of the
engine. I propose to do this. by means of a jet or shower of fused

page_text: metal, or compound of metals, or other suitable liquid or solution, not
liable to evaporation at the temperature and pressure used, introduced
into the working cylinder by means of a pipe, as at G, Figure 1, during
the expansion of the air, or by means of sheets of wire cloth, or wires, or
other forms of metal exhibiting an extending surface, see Figure 2, H,
heated by immersion in a bath, Figure 2, I, or reservoir placed in the
bottom of the working cylinder or fused metal or other heated liquid
not liable to. evaporation in the cylinder, and withdrawn from the
reservoir, and introduced into the working cylinder or expanding part
of the engine by the means of a metallic rod, Figure 2, J, or other
suitable apparatus connecting the wire cloth with the piston.
It appears from the recent experiment by Dr. Gorrie, con-
cerning the heat of compression and expansion of air above referred
to, that the quantity of sensible heat rentered latent by the expansion
of air of the tension of two atmospheres to the tension of one' atmo-
sphere is 277° Fahrenheit, a quantity too considerable to be neglected
without the most serious evil consequances; for, in the first place, the
requisite latent heat not being supplied, the air will be unable to expand
with full power, and the piston will be moved with greatly diminished
force; and, in the second place, the sensible temperature of the air in
the working cylinder will be materially lowered, in consequence of which
the beneficial effect of the apparatus intended to save and economise
the heat for repeated use hein-after mentioned, and sometimes called
the regenerator, is very much impaired.
The requisite latent heat may be supplied through the bottom of the
cylinder from the furnace, generally placed beneath the cylinder; but if
this mode be relied on, so much time must be occupied in communi-
cating the requisite heat that the engine will be inefficient from slowness.
Or, instead of supplying the heat rendered latent by means of apparatus
used in the working cylinder, I supply an equivalent quantity of sensible
heat to the air entering the working cylinder by means of an apparatus
placed in the pipe or channel connecting the force pump with the work-
ing cylinder; see Figure 3. This apparatus consists in a system or
quantity of wire cloth, wires, or other forms of metal exhibiting an
extending surface, Figure 3, K, heated to a suitable high degree by

page_text: immersion in a subjacent bath or reservoir, Figure 3, L, of fused metal
or other heated liquid not liable to evaporation at the heat required;
the submergence of the wire cloth being continued during the whole
time of the exit of the air from the working cylinder, and the wire
cloths being raised up into the pipe or channel so as to be in the course
of the air during its passage into the working cylinder. Or, instead of
a moveable system of wires, the wires may be rendered stationary in the
pipe or channel near the working cylinder, and heated by. a current or
blast of hot air from the furnace. The wires being cut off from the rest
of the machinery during their heating, and during the exit of the air
from the working cylinder, by means of suitable valves; another
channel being opened during this time for the exit of the air from the
working cylinder; the valves being so arranged and made to work that
during the entrance of the air into the working cylinder the current or
blast of hot air from the furnace shall be cut off, and the air from the
force pump shall pass through the heated wires on its way to the work-
ing cylinder. Or, instead of heated wires, a jet or shower of fused
highly heated metal or other suitable hot liquid may be substituted.
Or, instead of wires, a system or quantity of tubes of metal, round or
flattened in shape, may be placed in the pipe or channel, forming part
thereof, so that the air shall pass through them on its way to the work-
ing cylinder, and the tubes be heated on their outer surfaces by being
immersed in or surrounded by or subjected to a shower, current, or jet
of fused metal, or other suitable highly heated liquid; or the fused
metal or liquid may be passed through the tubes placed transversely to
the course of the air entering the working cylinder, the air being heated
by contact with the outside of the tubes on its passage.
. Another purpose of the Invention, which is applicable to what are
called close air engines, or engines in which the air, after having been
expanded in the working cylinder, is returned to the force pump to be
compressed for further use, is to lower the temperature of the air after
it has passed through the apparatus, intended to save and economise the
heat for repeated use, herein-after mentioned, and sometimes called the
regenerator, and before it enters the force pump.
This I do by means
of an apparatus placed in the pipe or channel, see Figure 4, M, con-

page_text: necting the working cylinder and the force pump. This apparatus
consists in a system or quantity of wire cloth, wires, or other forms of:
metal exhibiting an extended surface, Figure 4, N, cooled to a suitable
low degree by immersion in a subjacent bath or reservoir, Figure 4, O,..
of cold liquid; the submergences of the wire cloth being continued during
the whole time of the passage of the air through the pipe or channel on
its way to the working cylinder; and the wire cloths being raised up
into the pipe.or channel so as to be in the course of the air during its
passage from the working cylinder into the force pump. Or, instead of.
a moveable system of wires, the wires may be rendered stationary in the
pipe or channel, near the force pump, and cooled by a current of cold
liquid or cold air; the wires being cut off from the rest of the ma-
chinery during their cooling, and during the passage of the air from the
force pump to the working cylinder, by means of suitable valves; another
channel being opened during this time for the passage of the air from
the force pump to the working cylinder; the valves being so arranged
and made to work in well-known ways, that during the passage of the
air from the working cylinder to the force pump the current of cold.
liquid or cold air shall be cut off, and the air from the working cylinder
shall pass through the cooled wires on its way to the force pump, and
thus be lowered in temperature. Or, instead of cooled wires, a jet or
shower of cold liquid, as water, may be substituted. By these means.
the temperature of the air may be lowered to such a degree as to
compensate the latent heat rendered sensible by the compression of the
air in the force pump, and so dispense with and become a substitute
for the injection of a jet or shower of cold fluid into the force pump
for this purpose before mentioned. Or the temperature of the air may:
be lowered by this apparatus to such a degree only as may be necessary
to compensate for the rise of temperature which would otherwise take
place in consequence of the imperfect action of the apparatus herein-
after mentioned, and sometimes called the regenerator.
Another purpose of the Invention is, by means of an improved form
of the metal used for communicating or absorbing heat in the pipe or
channel connecting the force pump with the working cylinder, to
present a greater heating and cooling surface of metal, and also

page_text: to present to the currents of air or other matter less impediment and
resistance. This improved form of metal used is applicable to the
apparatus in the pipe or channel for heating and cooling the air herein-
before described, and is also applicable to the apparatus intended to save
and economise heat for repeated use, sometimes called the regenerator.
Instead of using for the alternate absorption and communication of
heat sheats of wire gauze, or sheets of perforated metal, or the other
forms which have been suggested for this purpose, I use strips, or tapes,
or ribbons of metal with sharp edges, so that when properly placed they
shall present the least resistance or impediment to the passage of the
air or other matter. The greater the quantity of metal requisite to
absorb the heat, the more important is it that the form of the metal
should be such as to take it up most rapidly, and present the. least
resistance to the current.
And to facilitate the attainment of the ends desired, I place the strips,
tapes, or ribbons of metal in, say, a series or system of wires, their sharp
edges being presented to the current, and I place each row in relation
to its adjoining row, so that the edges of the tapes of each row shall be
opposite to the intervals between the edges of the tapes of the adjoining
row; a horizontal section of the metallic tapes so arranged is presented,
Figure 5. Or I place the alternate rows, say, one vertically and the
adjoining one horizontally, the object being to cause the air or other
matters to be applied thoroughly and equally to the heating or cooling
surface of the metal.
Istead of the separate apparatus in the pipe or channel for heating
or cooling or saving the heat of the air before described, the effects of
all the three parts, or two of them, may be obtained by means of one
system or quantity of wire cloth, wires, or extended metal placed in the
pipe or channel apparatus for heating the end of the system next the
working cylinder, or cooling the end farthest from the working cylinder
being provided, for instance, apparatus for introducing upon the
respective ends, or one of them, a shower or blast of fused metal, or hot
liquid or hot air, or cold liquid or cold air.
Having thus described the nature of the Invention and the means of
putting it into operation, what I claim is,-

page_text: First, the absorbing of the latent heat given out by the air in the
compressing part of the engine by means of an injection of cold water
or other fluid, substantially as herein described.
Second, the supplying of heat to the air in the expanding part of the
engine by means of a jet or shower of fused metal, or other suitable
hot liquid, or by means of extended surfaces of metal, previously heated,
substantially as herein described.
Third, the reduction of the temperature of the air while entering, or
just before entering, the compressing part of the engine, by means
of a jet or shower of cold water or other liquid, or by means of extended
surfaces of metal which have been previously cooled, substantially as
herein described.
Fourth, the use, in the apparatus herein-before described for heating
and cooling and economising the heat of the air, of metallic tapes with
sharpened edges, and their arrangement, substantially as herein described.
Fifth, the combined use, in one pipe or channel between the com-
pressing and expanding parts of the engine, of all three, or any two, of
the apparatuses herein-before described for heating or cooling or econo-
mising the heat of the air, substantially as herein described.
In witness whereof, I, the said Moses Poole, have hereunto set
my hand and seal, this Twelfth day of September, in the year
of our Lord One thousand eight hundred and fifty-three.
MOSES POOLE. (L.S.)
Witness, WILLIAM E. DAVES,
Torquay, Devon.