CERTAIN IMPROVEMENTS IN OBTAINING MOTIVE POWER, AND THE MACHINERY EMPLOYED THEREIN
Year: 1852

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ANTOINE
MAURICE TARDY DE MONTRAVEL, of Paris, in the Republic of France,
Gentleman, now residing at Marseilles, in the Republic of France, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Royal
Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-fourth day of
March, in the fifteenth year--eighteen hundred and fifty-two-of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Antoine Maurice Tardy de Montravel, my exors, adñors, and assigns, Her
especial license, full power, sole privilege and authority, that I, the said
Antoine Maurice Tardy de Montravel, my exors, adññiors, and assigns, or such
others as I, the said Antoine Maurice Tardy de Montravel, my exors, adñiors,
and assigns, should at any time agree with and no others, from time to time
and at all times during the term of years therein expressed, should and law-
fully make, use, exercise, and vend, within England, Wales, and the Town
of Berwick-upon-Tweed, and in the Islands of Guernsey, Jersey, Alderney,
Sark, and Man, and also in all Her said Majesty's Colonies and Plantations
abroad, my Invention of "CERTAIN IMPROVEMENTS IN OBTAINING MOTIVE POWER,
AND THE MACHINERY EMPLOYED THEREIN;" in which said Letters Patent there is
contained a proviso that I, the said Antoine Maurice Tardy de Montravel;
shall cause a particular description of the nature of my said Invention, and in
what manner the same is to be performed, by an instrument in writing under
my hand and seal, to be enrolled in Her said Majesty's High Court of

page_text: Chancery within six calendar months next and immediately after the date of
the said in part recited Letters Patent, as in and by the same, reference being
thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Antoine Maurice Tardy de Montravel, do hereby declare that the nature of
my Invention, and the manner in which the same is to be performed, are
particularly described and ascertained in and by the following statement
thereof, referénce being had to the Drawings hereunto annexed, and to the
figures and letters marked thereon, that is to say :-
My Invention consists in the expansion of air and permanent gases by the
alternate heating and cooling of such air and gases contained in closed vessels
or cylinders, the heating being produced by the contact of fire, or any other
process capable of giving heat.
Figure 1 represents a cylinder containing compressed air. If this cylinder
be alternately heated and cooled, the difference of expansion will serve to
elevate and depress alternately a piston.
Figure 2 is a double-acting apparatus cylinder. A, A¹, is filled with compressed
air of equal density on each side of the piston P. The cylinder being heated
and cooled alternately on each side, the difference of expansion will produce a
powerful mechanical effect, the divisions of the cylinder being antagonist
vessels. The air may be compressed in the cylinder by a force pump at the
aperture X, X, or other known means, to any required density. The piston P
must retain by its weight or resistance this constant density as minimum, and
must yield only to a new force resulting from expansion. When the tem-
perature is raised the expansive force is capable of lifting a fresh weight
added to the piston. The mechanical effect will be at its maximum simul-
taneously with the maximum of the temperature at the beginning of the
motion of the piston; but no effect will be produced when the piston has
been raised to such a height that the expansive force of the compressed air,
diminished by the increase of the volume, forms an equilibrium to the weight
of the piston added to the weight of the atmosphere; then, if the closed air
be cooled to the temperature of the open air, the closed air will resume its
first volume, and the weight of the piston and of the atmosphere will become
in its turn superior, and will produce a new mechanical effect, and of which
the maximum will take place at the beginning of the fall, and the minimum at
the end. The result of this vertical motion will be the medium between the
maximum and the minimum, and this medium may be obtained as constant
force, first, by known means, such as fly wheels, or other combinations for
the transmission of motion; second, by loading the piston at the beginning of

page_text: the motion with the medium weight, which, by not absorbing the whole force
of the motive power at the beginning, will reserve an excess of force for the
end. A greater difficulty will occur on loading the piston P with a constant
and additional weight. In order to make it capable of compression, an enormous
expansive weight, gearing wheels, and other mechanical contrivances, may
render unnecessary the employment of too heavy weights, and reduce them to
the tenth or one hundredth of their weight, though producing the same
resistance; but in every case I think the system shown in Figure 2 of the
Drawings is the best and most conveniently applicable. The expansive force
is completely retained by the sides of the cylinder A, A', and by the resistance
to the motion of the piston. The vessel being heated on the side A, and
cooled or left at its first temperature on the side A¹, the cooling and heating
changing place, the piston is pushed in the contrary direction, and the side A¹
undergoes a reaction, and gives back what was at first lost by its resistance,
and so forth; that is to say, that at the first motion of the machine the
expansive force on the side A is neutralized in part by the increase of conden-
sation on the side A', but at the second stroke, the air on the side A', being-
more condensed and warmer, acts by this two-fold 'cause against the air on the
side A, which has become less dense, and is cooled in its turn.
In this system,
as in the first, the motion of the piston will be kept back an instant by a
simple mechanical arrangement, till the expansion produced by the maximum
of heat be attained.
Figure 3 is a contrivance to prevent the caloric from radiating from one
extremity of the cylinder to the other; however, it is not of an absolutė
necessity. The heat having caused expansion in the side A may radiate in the
side A', by following the metal sides; the air by being dilated in the side Ä
will absorb the heat from the surrounding bodies. By referring to Figure 3 a
glance at the Drawing will show the way in which the two portions of the
cylinder may be separated, and thus the heat prevented from radiating from
one portion of the cylinder to the other. One difficulty is to prevent as much
as possible any loss of condensed air, so as to make little use of the force
pumps. It is evident that air-tight pistons must be employed similar to those
usually employed for well-constructed steam engines. The following are
various kinds of pistons which may be used with advantage.
Figure 4 represents a system of making the pistons air-tight by the inter-
position of a liquid between the condensed air and the piston. Liquid does
not escape so easily as an elastic gas; besides, a kind of liquid paste composed
of clayey or fatty bodies may be used, and will escape less easily than a perfect
liquid.

page_text: Figure 4 represents a double-stroke engine of the simplest form. In the
cylinder C', C, it is not important that the piston P', P, should separate the
compressed air at C from that which is at C¹; it will be easy, however, to place
the two pistons P, P¹, at a certain distance from one another, and to introduce
in the space between the pistons a liquid M, S, thereby forming a perfectly
air-tight cocking. What is more important is, that the condensed air may
not escape by the stuffing boxes through which the piston rods T, T¹,
work. To prevent the escape of air the following method may be employed:-
The rod T is fitted with two pistons p, p'. These two pistons fit into the
interior of the tube A, B. Between the two pistons p, p, a liquid or paste
M, S, is inserted, and this liquid is compressed by a pressure equal to that of
the condensed air in the cylinder C, by means of a small reservoir adapted to
the orifice R, and containing likewise compressed air. The condensed air in
the reservoir which is fitted at R counterbalances the condensed air in the
cylinder C, so that the space m, 8, is always kept full, notwithstanding the
losses which might take place. The loss of liquid may be ascertained by
receiving it in a vessel suspended at the extremities of the tube A, B, at V.
Figure 5 represents a fixed apparatus or machine adapted for air-tight
pistons double-acting machines. FREP, FR' E' P¹, are two antagonist
cylinders formed of curved tubes, to be heated or cooled alternately. The
dotted spaces
show the condensed air in the tubes, the lined spaces
the part of the tubes containing a liquid. P, P¹, are the antagonist
pistons. One of the vessels being heated, the expanded air in the curved tube
F, F, causes the liquid to descend from E to I. The liquid forces the piston P
to one extremity of the tube P, Z. This piston forces back the antagonist
piston P' in the interior of the tube P, R, F, and throws back the cold air to
E. The contact of the caloric being intercepted at F, the cooling effect being
produced on the same side, the opposite tube F¹ is treated and expanded in its
turn, and so forth. The useful effect produced by this reciprocating motion
may be transmitted by a moveable piece X, X, placed between both pistons, or
fixed to the piston common rod. According to this system the air is never in
contact with the pistons, but only with a liquid. The loss of liquid may be
ascertained and replaced by the force pumps R, R, but these pumps must not
be confounded with the air pumps. Stout props M, M, will be necessary. to
keep up the bent pipes against the pushing in the direction of the to-and-fro
motion.
Figures 6, 7, and 8 represent a system of using air-tight bags closed in
cylinders, without pistons. In Figure 6, A, B, is a double cylinder, one part
being made to close; in the other, a tube or lining R, R, of waterproof and

page_text: elastic material is made of the shape of the cylinder. This tube is fixed to the
bottom of the two cylinders M, M', or to the sides of the same. The air is
condensed by a force pump fitted to an orifice D, and will constantly tend to
force the air-tight tube against the interior sides of the cylinder, bringing it in
perfect juxtaposition with them. This pressure would soon burst the tube if it
did not fit accurately to the interior sides of the cylinder; as it is, it keeps the
latter air-tight. When the bottoms M, M', are distant from one another, the
tube is stretched, but when the bottom M approaches the bottom M¹, as shewn
in Figure 7, it is obliged to shorten, but being constantly pressed against the
sides of the cylinder, it will roll itself up, thereby doubling its thickness at F, R,,
and forming an effectual air-tight junction between the two cylinders. The
packing at F, as the extremity of the piston cylinder, will make an ordinary
fastening, and prevent the tissue of the air-tight tube from wearing out against
the edges of the cylinder. The thickness of the air-tight material must be so
great as to exclude the possibility of its accidentally entering the open space
between the cylinders. The tube may be closed with rings of india rubber, its
length being proportionate to the length of the cylinder. By dispensing with
pistons, there is less chance of escape of air; the motion is transmitted outside
by the 'bottoms of the cylinders by connecting rods or other suitable mechanism.
Figure 7 represents the machine just described partly closed, and Figure 8
shews 'an arrangement whereby the two antagonist cylinders may be contained
either between 'two solid rests H, HI, or in one frame capable of withstanding
a drawing action or a lateral pressure proportionate to the expansive force of
the air compressed or expanded in the cylinders. The two fixed pieces H and
H' should always be at a certain distance asunder, but when the cylinder A²,
B', S', is distended, the cylinder A, B, becomes compressed, and so on according
as 'the caloric is made to act on each cylinder. A moveable piece L, L, placed
between the cylinders will transmit the motion so produced by chains or other
convenient mechanism. Figure 9 shews an arrangement for distributing the
heat and the cold alternately round the cylinders. A, cylinder capable of con-
taining air at a high pressure; HI, H, an external cylinder, which may be made
strong and firm for fixed machines. The cap D, K, is merely laid on, and.may
be removed at pleasure. R, R, is an annular space between the two cylinders,
A, H, forming a draught chimney and reverbatory furnace. K is the orifice of
the chimney more or less open; R, R, L, L, is a coating of fireproof cement
to protect the interior of the cylinder H against the injurious action of the
heat, thus making the space R, R, a perfect reverbatory furnace, and concen-
trating the caloric round the cylinder A. F is a kind of firegrate, having a

page_text: current of air passing through it. Two openings are made to open and close
The flame is thus directed
M, M³, connected with the
alternately by means of valves or dampers E, E¹.
at will round the cylinders A or A¹, by the flues
fireplace beneath the antagonist A', or by the flues N, N', alternately in two or
many other antagonist vessels X, X, forming a series of heating cylinders in
connection with the first just described. The first method is sufficient when
active means are used to effect quickly the cooling against the cylinder A,
while the flame does not circulate round.
The second method, shewn in Figure 10, will be useful when the cooling is
left to be made solely by the interruption of the action of A, A', and by the
bringing into action of X, X. Suppose an ascending current of flame or
burning air in the reverbatory furnace be thrown against the cylinder A, and
the passage opened to a current of cold air on the side B, while the flame
acts on the side of the cylinder A, and will cause the air it contains to expand.
The flame would melt the motal if the caloric were not absorbed by the
condensed air, but this air produces the effect of a liquid which hinders a
vessel exposed to the fire from being destroyed. The flame must be the
more ardent as the condensation of the air is greater. The grate must be
arranged to give a determinate temperature 90°; for instance, on the opposite
side B, the cool air circulating rapidly in the annular space R', R', will soon
have absorbed the quantity of caloric above to its own temperature, and this
effect will be produced much more quickly if the ascending air be made
damp by the injection of water in the form of mist or fine rain.
The most rapid transition from heat to cold may be produced by the
introduction, in the annular space R, R, of boiling liquid followed by a cold
liquid. If the temperature be raised to one hundred degrees, and if a regular
supply of liquid be conveyed round the burning sides of the cylinder A, and
thereby becoming immediately vaporized, the annular space R, R, will become
a perfect generator. This vapour, contained and directed by the ordinary
means, produces a new force, at the same time the cooling of the condensed
air produces another force, and one of these two forces is necessarily obtained
without loss of any kind.
For the less powerful machines, the two extremities of a cylinder will be
alternately heated by the raising of the valves and the pipes E, E, connected
to the same firegrate P, Figure 11. The flame will circulate in the annular
space R, R, and the exterior cylinder H will serve as a safeguard and con-
centration of the heat. For machines in which lightness is considered the
principal object, the firegrate F may contain a spirituous liquid, and be sus-

page_text: pended to the exterior cylinder or wrapper, being conveyed alternately from
one extremity of the cylinder to the other as shewn, Figure 12.
Figure 13. The cylinder may be filled with air at its natural density or
condensed to two or three atmospheres, but in all cases it must be closed
air-tight, and the piston immovable and fixed to the ground. A liquid is
interposed between the air and the piston, the total weight of the cylinder and
weights M, M, attached being sufficient to support the constant pressure of
the condensed air. If the cylinder A be exposed to the rays of a burning
sun, or the action of the solar rays be rendered intermittant by intercepting
them by a curtain or screen, the least difference, 10 or 20 degrees centigrade
for instance, between the maximum and the minimum of temperature will
produce an increase or diminution of the volume of air in the interior, and
will alternately raise or lower the cylinder. With this simple machinery great
effects may be obtained, such as raising water, et cetera.
Figure 14 is a system of antagonist cylinders which may be adopted.
p', p', are the pistons, A the condensed air, E water interposed between the
air and the pistons, if the air be condensed at a great density. By having a
half circular surrounding plate R, R, placed round each cylinder, and this
plate be made to reflect back the sun's rays against the cylinder, either by
mirrors or a polished or blackened surface, and supposing the sun's rays to
pass through panes of glass, V, increasing their effect and preventing at the
same time the caloric from radiating at the exterior, and if the circular
reflector, R, R, V, V, turning on a central pivot C by any suitable mechanism,
so as to present always the side V, V, to the sun, a constant temperature of
100 degrees and more may thus be obtained; and in lowering this temperature
in an intermittant manner in the cylinder A, by throwing water against the
cylinder, which will become vaporised and absorb the caloric the more
rapidly as the heat of the cylinder is greater, this is sufficient to obtain from
the heat of the solar rays a power equal to that of furnaces consuming a
large amount of fuel. The apparatus for keeping atmospherical air of but
small densities, and being under the influence of only some degrees of tem-
perature, are to be established of large size, for instance one meter of
diameter. All the apparatus here above described keeping atmospherical air
at high pressure, and being exposed to undergo considerable differences of
temperature, need to be at most 30 or 40 centimeters in diameter, and they
can be constructed with as much care and perfection as fire-arms.
Firstly, the system or mode of producing motive power by the application
of alternate heat and cold to atmospheric air or gases of any kind, such air or
gas being permanently confined in cylinders or other suitable vessels.

page_text: Secondly, the application and use of liquids or semi-fluid matter in-
terposed between the atmosphere and the piston in the manner and for the
purpose herein-before described.
Thirdly, the application and use of the various apparatus and machinery
herein-before described.
In witness whereof, I, the said Antoine Maurice Tardy de Montravel,
have hereunto set my hand and seal, this Tenth day of September,
One thousand eight hundred and fifty-two.
A. M. (Ls.) TARDY DE MONTRAVEL.
Taken and acknowledged by Antoine
Maurice Tardy de Montravel, party
hereto, at Marseilles, this Tenth day

page_text: AND BE IT REMEMBERED, that on the oath of John Philipe the
Specification aforesaid was enrolled word for word, as above written. And
also the Specification aforesaid was stamped according to the tenor of the
Statute made for that purpose.
Enrolled the Twenty-fourth day of September, in the year of our Lord
One thousand eight hundred and fifty-two.