IMPROVEMENTS IN THE OBTAINING MOTIVE POWER." MODE OF AND APPARATUS FOR
Year: 1868

page_text: LETTERS PATENT to Johann Maximilian Plessner, of No. 53, Rue
de la Chaussée d' Antin, Paris, in the Empire of France, for the
Invention of "IMPROVEMENTS IN THE
OBTAINING MOTIVE POWER."
MODE OF AND
APPARATUS FOR
Sealed the 28th August 1868, and dated the 6th April 1868.
PROVISIONAL SPECIFICATION left by the said Johann Maximilian
Plessner at the Office of the Commissioners of Patents, with his
Petition, on the 6th April 1868.
I, JOHANN MAXIMILIAN PLESSNER, of No. 53, Rue de la Chaussée
d'Antin, Paris, in the Empire of France, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN THE MODE OF AND APPARATUS
FOR OBTAINING MOTIVE POWER." to be as follows:-
My improvements in the mode of and apparatus for obtaining motive
power are based on the production of a partial vacuum by means of
the alternate rarefaction and cooling of atmospheric air.
In order to render intelligible the principle of the Invention, I
refer to the Figures 1 and 2 of the accompanying Drawings, in which

page_text: A is a vertical tube open at both extremities, which may be hermetically
closed at will by the obturators B, B'. The air contained in the
tube being rarefied by means of a lamp so arranged as to heat the
interior of the latter, the obturators are closed and the lower extremity
of the tube is immersed in a liquid C, Fig. 2. The obturator B'
being then withdrawn the liquid C, as the air cools down, rises in the
tube to a height corresponding with the difference existing between
the highest and the lowest temperatures to which the air had been
subjected. If the upper obturator B be then withdrawn, the liquid
will fall to its original level, the result of the operation being the
production of a given amount of power. It is evident that in
connecting the pneumatic tube above described with a cylinder provided
with a piston, the pressure of the outer atmosphere will give motion to
the latter as in ordinary steam engines, the rarefied air of the tube
being cooled by any suitable means.
Figs. 3 and 4 represent in section and elevation an application of
this principle to the construction of a motive engine with two pneumatic
tubes heated by a liquid fuel, such as petroleum oil. In these Figures
'A, A', are the pneumatic tubes each provided with a jacket B, B',
filled with cold water C; D, D', are conduits leading to the suction
tube E which communicates either directly with the working cylinder
or with a pneumatic reservoir (both invisible in the Drawing). a, a',
b, b', are slide valves which alternately open and close the tubes
A, A', so that during the heating of the one the other is closed to
withdraw the air from the working cylinder or from the pneumatic
reservoir, as the case may be. J is the reservoir for the liquid fuel
feeding the lamps K, K. The alternate opening and closing of the
slide valves is effected by means of a vertical shaft F working the
toothed wheel c by a driving belt which passes under the pulley d
and from thence over a drum mounted on the shaft of the fly-wheel.
1 and I are excentric bars mounted on the shaft F and acting on
the slides for the opening and closing of the pneumatic tubes.
In order to render more intelligible the action of these excentric bars
I will indicate by letters in the following manner the different orifices
of the pneumatic tubes. G is the upper orifice of the tube A;
H lower orifice of the same; G' and H' are the corresponding orifices
of the tube A'. The tubes D, D', are fitted with self-acting
valves. Supposing the lamp lighted in the tube A, the orifices G, H,

page_text: are opened and the valve of the tube D is closed while the orifices*
G', H', of the tube A' are closed and the valve of D' is opened..
The air being heated to the required degree in the tube A, the
orifices G, H, close, the lamp of the tube A is extinguished, and
the valve of the tube D opens. At this moment the valve of D' of
the tube A' closes, and immediately after the orifices G' et H' open.
The lamp of this tube lights and rarefies the air; this done, the orifices:
G', H', close, the valve of D' opens, while the contrary action takes
place in the tube A, and so on successively for each of the tubes.
To enable this combination of alternative openings and closings to.
be effected with regularity by the rotation of the shaft F, I employ
the following arrangement:-In supposing the shaft to revolve from
right to left, the pin 1 which has just closed the orifice G' by means
of the slide A will take up position in the line of communication of
the centres of G' and G. The pin I instead of being exactly in line
under 1, forms with the latter a slight angle, the result being that
the upper orifice G' will always be closed a moment before the lower
orifice H', and consequently that the orifice,G of the other tube will
open a moment in advance of H. In the same manner G' will open
a moment before H' and so on, thus ensuring the due succession of
the opening and closing motions.
This arrangement may be, if desired, modified as follow:-The two
tubes A, A', being set close to each other a single lamp placed between
them may be substituted to the pair employed in the system above
described, so that the flame may be drawn alternately into one or
other of the tubes according as their orifices may be open or closed,
thus obviating the necessity of, extinguishing and re-lighting the lamps.
Any lamp producing a flame of the required intensity and height may
be employed for the rarefaction of the air in the pneumatic tubes. The
cooling of the pneumatic tubes may be effected by any of the known
processes, such as by the circulation of a current of cold water from
a suitable reservoir. In certain cases, and when circumstances do not
permit of large supplies of water, the tubes may be provided with
jackets or envelopes of porous clay of slightly larger diameters so as to
leave but the space required for a thin sheet of water. The evaporation
at the outer surface of this porous, envelope will suffice to maintain
the tubes at a sufficiently low temperature, care being taken to keep the

page_text: water in circulation. This mode of refrigeration may be rendered still
more efficient by the introduction of air from a pump or blowing
apparatus, and if so desired the porous envelope may be surrounded
by a metallic case, space being reserved between the two for a thin
layer of air, this inner space being hermetically closed from the outer
air but communicating by a tube with a vessel containing sulphuric
acid. The air being constantly rarefied by a pump the aquous vapors
are absorbed by the sulphuric acid, thus causing a considerable reduction
of the temperature. However short may be the space of time required
for the expansion of the column of air within the pneumatic tubes,
this space of time is nevertheless appreciable. In supposing the shortest
duration of the action of the flame to be one second the motion of
the engine will remain uniform if each stroke of the piston occupies
the same space of time; when therefore the capacity of the driving
cylinder is such that its volume of air suffices to fill the discharge
tube with air at the normal tension, and that the resistance to be
overcome is such that the operation occupies one second of time.
The piston commences its stroke under a pressure of, say, three-fourths
of an atmosphere, and finishes it with zero. At the end of the stroke
the suction pipe of another pneumatic tube opens and the piston
commences and finishes its return stroke under the same pressure as
before. The action of the machine is in this case identical with that
of the ordinary expansion steam engine, but when higher velocity is
required it would be disadvantageous to provide a pneumatic tube for
each stroke of the piston, whence it results that the quantity of air
'displaced in each tube should be for a speed of one hundred and eighty
revolutions per minute, for instance, six times greater than the volume
of air contained in the driving cylinder. In this case again the piston
commencing its sixth stroke with one-sixth of its original force will
complete it with zero. In order to ensure regularity in the motion of
the piston, and particularly when it is desired to dispense with fly-
wheels of large dimensions, I provide a pneumatic reservoir, which,
though drawing the air from the tubes, may be brought to a high
degree of rarefaction before the starting of the engine. The suction tube
connects the driving cylinder with this reservoir, which on the other
hand communicates with the pneumatic tubes by means of a suitable
conduit. By increasing the volume of air compared with the capacity
of the driving cylinder we reduce the difference of pressure under which
the piston works. In supposing for instance that the capacity of the

page_text: pneumatic reservoir be one hundred times greater than that of the
driving cylinder, and that twenty strokes of the piston be required
before the pneumatic tubes communicate anew with the reservoir,
the first stroke of the piston will be effected under a pressure of 1000
the second under a pressure of 100, the twentieth under a pressure
of and the piston will commence its twenty-first stroke under a
pressure of 100 and so on continuously. We thus obtain an easy means
of increasing the duration of the heating process, and of cooling more
completely the pneumatic tubes.
100'
Fig. 5. represents the pneumatic reservoir on an enlarged scale. In
this Figure R is a bent pipe at the foot of the reservoir provided in its
vertical branch with a piston r, the rod of which is connected with a
slide P having a circular opening of a diameter equal to the cross
section of the suction pipe R' and actuated by the rack Z, the toothed
sector M, the lever H, and the weight G. Supposing this slide to
be so placed that the pipe R' communicates with the pneumatic
reservoir K by a small opening only, I obtain a regulator by aid of
which the successive strokes of the piston may be efficiently controlled.
It will be understood that we are thus enabled to adjust at will the
lever H by means of the weight G, and consequently to regulate the
pressure of the air in such a manner that at each six strokes of
the piston (always supposing the fly-wheel driven at one hundred and
eighty revolutions per minute) the suction tube R' will open by one-sixth
at each stroke till entirely opened at the completion of the sixth stroke.
At the first stroke of the piston the air cannot be totally exhausted
while the pneumatic reservoir is at its highest degree of rarefaction, and
this complete exhaustion will only be effected at the sixth stroke, that
is to say, when the volume of air has already been condensed by one-
fifth. A regulator may readily be constructed in such a manner that
the communication between the pneumatic reservoir and the driving
cylinder shall be completely intercepted, and even that at the first
stroke of the piston the cylinder (as in the expansion steam engine)
shall only remain for a short space of time in communication with the
reservoir, so as to avoid being suddenly carried to a high degree of
rarefaction. At the second stroke of the piston the suction tube will
remain open somewhat longer, and so on successively to the completion
of the sixth stroke, when it will be completely opened. The degree of
rarefaction in the reservoir K is ascertained by the barometer B. X is

page_text: the pipe by which the reservoir is connected with the pneumatic tubes.
The driving cylinder, the piston, the fly-wheel, and other working parts
of the machine are similar to those of the ordinary steam engine. In
certain circumstances it may be desirable to have the pneumatic tubes
set horizontally instead of vertically, in which case the draft suffices
to carry the flame into the open tube event at a deflection of ninety
degrees. The flame of a lamp placed between two horizontal tubes
having their axes in the same line will pass alternately into the two
tubes, its deflection being thus equivalent to 180°, its vertical jet being
of course first checked by any suitable means. The change in the
direction of the flame may be effected in any other convenient manner,
as for instance, by means of two tubes, one vertical and the other
horizontal, or again, by means of two tubes set horizontally so that their
axes form a right angle, or even.. by four horizontal tubes so arranged
that their prolonged axes intersect each other at right angles. In order
to obtain flames of the greatest length and intensity a current of air
or of a suitable gas may be passed into the tubes from below through
the axis of the cone of the flame. This current (when air is employed)
may be supplied by a small force pump worked by the engine.
.
In the preceding description I have only alluded to the use of liquid
fuel as the most generally applicable, but will now proceed to describe
the means by which solid fuel may be used when circumstances admit.
The use of coal involves, in the first place, the adoption of a furnace;
in the next, its action cannot be brought to bear on the air of the
pneumatic tubes as directly as that of liquid fuel, so that it becomes
necessary to heat the air in separate reservoirs and to carry it thereafter
to the pneumatic tubes. The form of the reservoir should be such as
to provide for the simultaneous heating of the largest possible quantity
of air, and for the immediate contact of all the parts of this air with the
heating medium so as to produce the maximum degree of temperature.
The most advantageous arrangement should therefore consist in a
serpentine series of tubes placed between two layers of coal or other
fuel.
Fig. 6 represents a furnace constructed on this principle, one of
the side plates being removed to render visible the internal arrangement.
In this Figure A, A, are the fire-doors for the introduction of the fuel.
At the outside-of the opposite wall project the extremities a, b, of
the serpentine tube x to which the cold air is supplied through the

page_text: orifice a by a force pump. This air heated in the tube x passes by b
into the conduit L, and from thence into the water chest B-containing
the pneumatic tubes from which it expels the cold air. After the
closing of the tube the condensation takes place in the manner
described. In this engine the conduit L. should be divided, as shewn
in the Drawing, or in any other equivalent manner, so as to displace
the cold air in the lower parts of the tubes and in immediate contact
with its sides. The other parts of this machine are similar to those
described in the arrangement shewn in Figures 3 et 4.
In certain cases a gas flame of any suitable description may be
substituted to the liquid and solid fuels, the general arrangement of
the machine being maintained as described.
The main difference between my atmospheric pressure engine
worked by gas and the ordinary "gas engine" lies in the fact that
in the first case I only utilize the high temperature of the gas in
combustion, whilst in the second case the explosive force of the gas
constitutes the motive agent. The alternate ignition and extinction of
the gas may be obtained by a stop-cock, which if desired may be so
regulated as to leave only at a given moment a slight blue flame, thus
obviating the necessity of total extinction and the consequent re-lighting
of the burner.
I will now describe certain special applications of the principle
on which my Invention is based.
Figs. 7, 7, represent an application of the Invention to the direct
elevation of water. In these Figures A, A', are the pneumatic tubes
provided with a lamp L; B is the pneumatic reservoir into which the
water is drawn; this reservoir is divided internally into two compartments
closed from each other; W is the induction pipe through which the
water is carried to the reservoir B, and distributed alternately into its two
compartments by means of the branch pipes v, v'; S, S', are two pipes
which connect alternately the pneumatic tubes A, A', with the two
compartments I, II, of the reservoir; F, F', are the discharge pipes,
which together with S, S', and v, v', open and close alternately by
means of self-acting valves. The pipe effects the cooling of the
pneumatic tubes by means of a small quantity of water taken from
the reservoir B, and which flowing off in y gives motion to a turbine
by which the slide valves of, the tubes A, A', are actuated. It is
unnecessary to add that the cooling of these tubes may be effected

page_text: in any other convenient manner. t, t', are two valves connected by
a lever pivoted in U. When the water is drawn into the compartment I
of the reservoir the valve t is closed by the pressure of the outer air,
while t' is opened by the action of the lever to allow the water to
escape from the compartment II.
Fig. 8 represents an application of my Invention to the propulsion
of ships or vessels. In this application the machine may act either
by the direct elevation of the water and its discharge from one and
other sides of the vessel; or again, it may be connected with a
working cylinder in combination with any other propelling apparatus
of suitable description. In the first case the suction tube S com-
municates with a pneumatic water reservoir, as in Figures 7; in the
second, the tube communicates with a pneumatic reservoir (Fig. 5)
in combination with a driving cylinder or with the latter alone,
according to circumstances. K, K, K', K', are two series of pneumatic
tubes acting alternately in the manner already described and fitted in
a chamber or reservoir G, in which cold water is kept in circulation
for the cooling of the tubes. By means of the pipes B, B, the
pneumatic tubes communicate with the pipes A, A', situated on
each side of the chamber G and connected with the suction pipe S
and
in front of the apparatus; x, x', are slide valves which open
close alternately the communication between the pipes A, A', and S.
The slides H, H, H', H', open and close alternately and simultaneously
The
the upper and lower orifices of the pneumatic tubes K, K'.
space between these tubes should be somewhat greater than the
diameter of their cross section, so as to allow the simultaneous action
of the slide valves. a, a, a, are the ports by which the lamps are
lighted to set the engine in motion or extinguished for stoppage.
The slides H, H, H', H', x, x', are worked by the bands D, D', D",
connected with a turbine or with a drum mounted on the shaft of
the fiy-wheel; as the case may be.
Figs. 9, 10, represent a modification of the above. Fig. 9 shews
in cross section the cylinders A, A', B, B', which are provided with
four double pistons. Fig. 10 represents in longitudinal section the
two double pistons C, C, C', C', which work in the cylinders A, A'.
In this Figure S is the prolongation of the suction tube S, Figure 8,
through which passes the air contained in the chambers D, D',
situated between the double pistons C, C, C', C',
according as the

page_text: orifices a, a', are opened or closed.
These orifices as also those
The
marked b, b', are alternately opened and closed by the arms c, c',
which work the slides d, d', e, e', by means of the vibratory motion
imparted to them by the arm f and by the studs g or g'.
rods E, E', of the pistons are each provided with a rack gearing
with the toothed wheel F, on the shaft h of which are mounted
freely the arms c; c', et f; i, i', are orifices for the admission of the
outer air into the space between the parts C, C', of the pistons in
contact with the water and the bridges I, I'.
It will be understood from the preceding description that my
Invention may be applied to all purposes requiring the employment
of motive power, the form, dimensions, and general details of con-
struction of the machines being varied according to their intended
application.
SPECIFICATION in pursuance of the conditions of the Letters Patent!
filed by the said Johann Maximilian Plessner in the Great Seal.
Patent Office on the 7th September 1868.
I, JOHANN
TO ALL TO WHOM THESE PRESENTS SHALL COME,
MAXIMILIAN PLESSNER, of No. 53, Rue de la Chaussée d'Antin,
Paris, in the Empire of France, send greeting.
.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of April, in the year of our
Lord. One thousand eight hundred and sixty-eight, in the thirty-first
year of Her reign, did, for Herself, Her. heirs and successors, give. and
grant unto me, the said Johann Maximilian Plessner, Her special
licence that I, the said Johann Maximilian Plessner, my executors,
administrators, and assigns, or such. others as I, the said Johann
Maximilian Plessner, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all
times. thereafter during the term therein expressed, 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 THE MODE OF AND APPARATUS FOR OBTAINING
MOTIVE POWER," upon the condition (amongst others) that I, the said
Johann Maximilian Plessner, my executors or administrators, by an

page_text: instrument in writing under my, or their, or one of their hands and
seals, 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 immediately after the date of the said
Letters Patent.
NOW KNOW YE. that I, the said Johann Maximilian Plessner, do
hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the Figures
of the accompanying Drawings, and to the letters marked thereon, that
is to say
My improvements in the mode of and apparatus for obtaining motive
power are based on the production of a partial vacuum by means of
the alternate rarefaction and cooling of atmospheric air.
In order to render intelligible the principle of the Invention I refer
to the Figs. 1 and 2 of the accompanying Drawings, in which A is
a vertical tube open at both extremities, which may be hermetically
closed at will by the obturators B, B¹. The air contained in the tube
being rarefied by means of a lamp so arranged as to heat the interior
of the latter the obturators are closed, and the lower extremity of the
tube is immersed in a liquid C, Fig. 2. The obturator B' being then
withdrawn the liquid C, as the air cools down, rises in the tube to a
height corresponding with the difference existing between the highest
and the lowest temperature to which the air had been subjected. If
the upper obturator B be then withdrawn the liquid will fall to its
original level, the result of the operation being the production of a
given amount of power. It is evident that in connecting the pneumatic
tube above described with a cylinder provided with a piston, the pressure
of the outer atmosphere will give motion to the latter as in ordinary
steam engines, the rarefied air of the tube being cooled by any suitable
means.
Figs. 3 and 4 represent in section and elevation an application of
this principle to the construction of a motive engine with two pneumatic
tubes heated by a liquid fuel, such as petroleum oil. In these Figures
'A, A', are the pneumatic tubes, each provided with a jacket B, B', filled
with cold water C. D, D, are conduits leading to the suction tube E,
which communicates either directly with the working cylinder or with

page_text: a pneumatic reservoir (both invisible in the Drawing); a, a, b, b', are
slide valves, which alternately open and close the tubes A, A', so that
during the heating of the one the other is closed to withdraw the air
from the working cylinder or from the pneumatic reservoir, as the case
may be. J is the reservoir for the liquid fuel feeding the lamps, K, K'.
The alternate opening and closing of the slide valves is effected by
means of a vertical shaft F working the toothed wheel c by a driving
belt, which passes under the pulley d, and from thence over a drum
mounted on the shaft of the fly-wheel. 1 and I are excentric bars
mounted on the shaft F and acting on the slides for the opening and
closing of the pneumatic tubes.
In order to render more intelligible the action of these excentric bars
I will indicate by letters in the following manner the different orifices
of the pneumatic tubes. G is the upper orifice of the tube A; H, lower
orifice of the same; G' and H' are the corresponding orifices of the
tube A'. The tubes D, D' are fitted with self-acting valves. Supposing
the lamp lighted in the tube A, the orifices G, H, are opened and the
valve of the tube D is closed, while the orifices G', H' of the tube A'
are closed, and the valve of D' is opened. The air being heated to the
required degree in the tube A the orifices G, H, close, the lamp of
the tube A is extinguished, and the valve of the tube D opens. At
this moment the valve of D' of the tube A' closes, and immediately
after the orifices G' and H' open. The lamp of this tube lights and
rarefies the air; this done, the orifices G', H' close, the valve of D'
opens, while the contrary action takes place in the tube A, and so on
successively for each of the tubes.
To enable this combination of alternate openings and closings to be
effected with regularity by the rotation of the shaft F, I employ the
following arrangement:-In supposing the shaft to revolve from right
to left, the pin 1 which has just closed the orifice G' by means of the
slide A will take up position in the line of communication of the
centres of G and G'. The pin I, instead of being exactly in line under 1,
forms with the latter a slight angle, the result being that the upper
orifice G will always be closed a moment before the lower orifice H',
and consequently that the orifice G of the other tube will open a
moment in advance of H. In the same manner G' will open a moment
before H', and so on, thus ensuring the due succession of the opening
and closing motions.

page_text: This arrangement may, if desired, be modified as follows:-The two
tubes A, A', being set close to each other, a single lamp placed between
them may be substituted to the pair employed in the system above
described, so that the flame may be drawn alternately into one or other
of the tubes according as their orifices may be open or closed, thus
obviating the necessity of extinguishing and re-lighting the lamps. Any
lamp producing a flame of a required intensity and height may be
employed for the rarefaction of the air in the pneumatic tubes. The
cooling of the pneumtic tubes may be effected by any of the known
processes, such as by the circulation of a current of cold water from
a suitable reservoir. In certain cases, and when circumstances do not
permit of large supplies of water, the tubes may be provided with
jackets or envelopes of porous clay of slightly larger diameters, so as
to leave but the space required. for a thin sheet of water. The
evaporation at the outer surface of this porous envelope will suffice to
maintain the tubes at a sufficiently low temperature, care being taken
to keep the water in circulation. This mode of refrigeration may be
rendered still more efficient by the introduction of air from a pump
or blowing apparatus, and, if so desired, the porous envelope may be
surrounded by a metallic case, space being reserved between the two
for a thin layer of air, this inner space being hermetically closed from
the outer air, but communicating by a tube with a vessel containing
sulphuric acid. The air being constantly rarefied by a pump, the
aquous vapors are absorbed by the sulphuric acid, thus causing a
considerable reduction of the temperature. However short may be the
space of time required for the expansion of the column of air within
the pneumatic tubes, this space of time is nevertheless appreciable. In
supposing the shortest duration of the action of the flame to be one
second, the motion of the engine will remain uniform if each stroke
of the piston occupies the same space of time. When therefore the
capacity of the driving cylinder is such that its volume of air suffices
to fill the discharge tube with air at the normal tension, and that the
resistance to be overcome is such that the operation occupies one second
of time, the piston commences its stroke under a pressure of, say, three-
fourths of an atmosphere and finishes it with zero. At the end of the
stroke the suction pipe of another pneumatic tube opens, and the
piston commences and finishes its return stroke under the same pressure
as before. The action of the machine is in this case identical with that
of the ordinary expansion steam engine, but when higher velocity is

page_text: required it would be obviously disadvantageous to provide a pneumatic
tube for each stroke of the piston, whence it results that .the quantity
of air displaced in each tube should be for a speed of one hundred and
eighty revolutions per minute, for instance, six times greater than the
volume of air contained in the driving cylinder. In this case again
the piston commencing its sixth stroke with one-sixth of its original
force will complete it with zero. In order to ensure regularity in the
motion of the piston, and particularly when it is desired to dispense
with fly-wheels of large dimensions, I provide a pneumatic reservoir,
which though drawing the air from the tubes may be brought to a
high degree of rarefaction before the starting of the engine. The suction
tubes connect the driving cylinder with the reservoir, which on the
other hand communicates with the pneumatic tubes by means of a
suitable conduit. By increasing the volume of air compared with the
capacity of the driving cylinder, we reduce the difference of pressure
under which the piston works. In supposing, for instance, that the
capacity of the pneumatic reservoir be one hundred times greater than
that of the driving cylinder, and that twenty strokes of the piston be
required before the pneumatic tubes communicate anew with the
reservoir, the first stroke of the piston will be effected under a pressure
of 100, the second under a pressure of
the twentieth under a
pressure of, and the piston will commence its twenty-first stroke
under a pressure of 100, and so on continuously. We thus obtain an
easy means of increasing the duration of the heating process, and of
cooling more completely the pneumatic tubes.
99
100
1
Fig. 5 represents the pneumatic reservoir on an enlarged scale. In
this Figure, R is a bent pipe at the foot of the reservoir provided in
its vertical branch with a piston r, the rod of which is connected. with
a slide P having a circular opening of a diameter equal to the cross
section of the suction pipe R and actuated by the rack Z, the toothed
sector M, the lever H, and weight G. Supposing this slide to be so
placed that the pipe R' communicates with the pneumatic reservoir K
by a small opening only, I obtain a regulator by aid of which the
successive strokes of the piston may be efficiently controlled. It will
be understood that we are thus enabled to adjust at will the lever H
by means of the weight G, and consequently to regulate the pressure
of the air in such a manner that at each six strokes of the piston
(always supposing the fly-wheel driven at 180 revolutions per minute)

page_text: the suction tube R' will open by one-sixth at each stroke till entirely
opened at the completion of the sixth stroke. At the first stroke
of the piston the air cannot be totally exhausted while the pneumatic
reservoir is at its highest degree of rarefaction, and this complete
exhaustion will only be effected at the sixth stroke, that is to say,
when the volume of air has already been condensed by one-fifth. A
regulator may be readily constructed in such a manner that the
communication between the pneumatic reservoir and the driving
cylinder shall be completely intercepted, and even that at the first
stroke of the piston the cylinder (as in the expansion steam engine)
shall only remain for a short space of time in communication with
the reservoir, so as to avoid being suddenly carried to a high degree
of rarefaction. At the second stroke of the piston the suction tube
will remain open somewhat longer, and so on successively to the
completion of the sixth stroke, when it will be completely opened.
The degree of rarefaction in the reservoir K is ascertained by the
barometer B. X is the pipe by which the reservoir is connected with the
pneumatic tubes. The driving cylinder, the piston, the fly-wheel,
and other working parts of the machine are similar to those of the
ordinary steam engine. In certain circumstances it may be desirable
to have the pneumatic tubes set horizontally instead of vertically, in
which case the draft suffices to carry the flame into the open tube even
at a deflection of 90°. The flame of the lamp placed between two
horizontal tubes, having their axes in the same line will pass alternately
into the two tubes, its deflection being thus equivalent to 180°, its
vertical jet being of course first checked by any suitable means. The
change in the direction of the flame may be effected in any other
convenient manner, as, for instance, by means of two tubes, one vertical
and the other horizontal, or again by means of two tubes set horizontally
so that their axes form a right angle, or even by four horizontal tubes
so arranged that their prolonged axes intersect each other at right
angles. In order to obtain flames of the greatest length and intensity
a current of air or of a suitable gas may be passed into the tubes
from below through the axes of the cone of the flame. This current
(when air is employed) may be supplied by a small force pump worked
by the engine.
In the preceding description I have only alluded to the use of liquid
fuel as the most generally applicable, but will now proceed to describe

page_text: the means by which solid fuel may be used when circumstances admit!
The use of coal involves, in the first place, the adoption of a furnace;
in the next, its action cannot be brought to bear on the air of the
pneumatic tubes as directly as that of liquid fuel, so that it. becomes
necessary to heat the air in separate reservoirs and to carry it thereafter
to the pneumatic tubes. The form of the reservoirs should be such
as to provide for the simultaneous heating of the largest possible
quantity of air, and for the immediate contact of all the parts of this
air with the heating medium so as to produce the maximum degree
of temperature. The most advantageous arrangement should there-
fore consist in a serpentine series of tubes placed between two layers
of coal or other fuel.
: :
Fig. 6 represents a furnace constructed on this principle, one of the
side plates being removed to render visible the internal arrangement.
In this Figure A, A, are the fire-doors for the introduction of the fuel.
At the outside of the opposite wall project the extremities a, b, of the
serpentine tube to which the cold air is supplied through the orifice a
by a force pump. This air heated in the tube x passes by 6 into the
conduit L, and from thence into the water chest B containing the
pneumatic tubes from which it expels the cold air. After the closing of
the tube the condensation takes place in the manner described. In this
engine the conduit L should be divided, as shewn in the Drawing, or in
any other equivalent manner, so as to displace the cold air in the lower
parts of the tubes and in immediate contact with its sides. The other
parts of this machine are similar to those described in the arrangement
shewn in Figs. 3 et 4.
In certain cases a gas flame of any suitable description may' be
substituted to the liquid and solid fuels, the general arrangement of the
machine being maintained as described.
The main difference between my atmospheric pressure engine worked
by gas and the ordinary "gas engine" lies in the fact that in the first
case I only utilise the high temperature of the gas in combustion, whilst
in the second case the explosive force of the gas constitutes the motive
agent.
The alternate ignition and extinction of the gas may be obtained
by a stop-cock, which, if desired, may be so regulated as to have only at
a given moment a slight blue flame, thus obviating the necessity of
total extinction and the consequent re-lighting of the burner.

page_text: Figs. 7, 7 represent an application of the Invention to the direct eleva-
tion of water. In these Figures A, A', are the pneumatic tubes provided
with a lamp L; B is the pneumatic reservoir into which the water is drawn;
this reservoir is divided internally into two compartments closed from
each other; W is the induction pipe through which the water is carried
to the reservoir B, and distributed alternately into its two compartments
by means of the branch pipes v, v'; S, S', are two pipes which connect
alternately the pneumatic tubes A, A', with the two compartments I, II,
of the reservoir; F, F', are the discharge pipes, which together with
S, S', and v, v', open and close alternately by means of self-acting valves.
The pipe x effects the cooling of the pneumatic tubes by means of a
small quantity of water taken from the reservoir B, and which flowing
off in y gives motion to a turbine by which the slide valves of the
tubes A, A', are actuated. It is unnecessary to add that the cooling of
these tubes may be effected in any other convenient manner. t, t', are
two valves connected by a lever pivoted in U. When the water is
drawn into the compartment I of the reservoir the valve t is closed by
the pressure of the outer air, while t' is opened by the action of the
lever to allow the water to escape from the compartment II.
Fig. 8 represents an application of my Invention to the propulsion of
ships or vessels. In this application the machine may act either by the
direct elevation of the water and its discharge from one and other sides
of the vessel; or again, it may be connected with a working cylinder in
combination with any other propelling apparatus of suitable description.
In the first case the suction tube S communicates with a pneumatic
water reservoir, as in Fig. 7; in the second the tube communicates
with a pneumatic reservoir (Fig. 5) in combination with a driving
cylinder or with the latter alone, according to circumstances.
K, K, K', K', are two series of pneumatic tubes acting alternately in
the manner already described, and fitted in a chamber or reservoir G in
which cold water is kept in circulation for the cooling of the tubes. By
means of the pipes B, B, the pneumatic tubes communicate with the
pipes A, A, situated on each side of the chamber G and connected with
the suction pipe S in front of the apparatus; x, x', are slide valves which

page_text: turbine or with a drum mounted on the shaft of the fly-wheel, as the case
may be.
Figs. 9, 10, represent a modification of the above. Fig. 9 shews
in cross section the cylinders A, A, B, B', which are provided with
four double pistons. Fig. 10 represents in longitudinal section the
two double pistons C, C, C', C', which work in the cylinders A, A'.
In this Figure S is the prolongation of the suction tube S, Fig. 8,
through which passes the air contained in the chambers D, D', situated
between the double pistons C, C, C', C', according as the orifices a, a',
are opened or closed. These orifices, as also those marked b, b', are
alternately opened and closed by the arms c, c', which work the slides
d, d', e, e', by means of the vibratory motion imparted to them by the
arm and by the studs or g'. The rods E, E', of the pistons are each
provided with a rack gearing with the toothed wheel F on the shaft on
which are mounted freely the arms c, c', and f; i, ', are orifices for the
admission of the outer air into the space between the parts C, C', of the
pistons in contact with the water and the bridges I, I'.
Figs. 11, 12, 13, represent in vertical and cross sections and elevation
an application of this principle to the construction of a motive engine with
one pneumatic tube or cylinder heated by a liquid fuel, such as petroleum.
In these Figures A is the pneumatic tube or cylinder having a lateral
orifice a for the passage of the flame. The upper extremity of this
cylinder is opened and closed at will by the valve in the manner
hereafter described. B is a rectangular water tank containing another
reservoir of cylindrical form E, Fig. 13; C, Figs. 11, 12, is the turbine,
the outer periphery of which is indicated by c, Fig. 13; D is a pipe
connecting the turbine with the pneumatic cylinder; F is the shaft of
the turbine, and G the transmission gear; J, J', are the liquid fuel

page_text: reservoir and feeding arrangement. The valve b being opened the
orifice a is opened in its turn, and the flame passing into the cylinder
A, as shewn in Fig. 11, expells through the upper orifice a large
proportion of the air contained therein. The valve b and the orifice
a being then simultaneously closed, the water rises into the pneumatic
cylinder A through the pipe D traversing the pallets of the turbine,
which is thus set in motion; the valve b being then opened anew,
the water falls back by its own weight and again passes through the
turbine, which continues to revolve in the same direction. The
difference between the ascending and the descending force of the
water is equalised in a few seconds after the starting of the engine
by the continuous rotation of the water in the circular reservoir E.
This difference may also be avoided by substituting two pneumatic
cylinders. working alternately to the single cylinder shewn in the
Drawing. The action of the valve band of the orifice a is controlled
by the cylinder H, Figs. 11, 12, 13, the details of which are represented
on an enlarged scale in Figs. 14, 15. In these latter Figures (14, 15,)
I, II, are two pistons working in opposite directions. When the
water rises it passes through the conduit K between these pistons, forcing
the first I to rise and the other II to descend, the former expelling
the air by the valve c and compressing the spring d. To the rod of
this piston 1 are connected two bars h, h', Fig. 14, provided with
projections i, ', which strike against the ends of the levers h, k, the said
ends being so jointed as to fold back on the up stroke of the piston I
without giving motion to the levers which can only come into play
on the down stroke. On the up stroke of the piston I the plate l,
Figs. 11, 20, hinged to the pneumatic cylinder also rises. The hinge
pivot of this plate is prolonged to the outside of the cylinder and is
connected with the lever a, Fig. 20, which on the rise of the plate
comes above the lever "" articulated in the same manner ask,
When the water has reached its highest level, the plate commences
to fall by its own weight; the lever a presses against "" which lowers
the rod c, and the latter opens an orifice for the admission of air
into the pneumatic cylinder A. At this moment the water falls.
accelerating the fall of the plate ; the lever a is thus forced to depress
still further the rod c by means of the lever "". The rod c acts on the
lever which presses against the arm e secured to the shaft of the
cam h, Fig. 20. This shaft is also provided with an arm f and with

page_text: 7'.
a bar carrying the spring By the action of the lever d on the arm
e, the cam turns and opens the valve b, Figs. 11, 12; at the same
moment the arm f catches in the notch g, and the spring is thus
expanded. When the water falls below the pipe K, the piston II is
returned to its first position by the spring d'. In rising this piston
II opens the orifice e, which it had closed in its down stroke, and
the air passes by this orifice through the tube f, Fig. 15, and the
stop-cock y into the space above the piston I. The latter then descends
carrying with it the rods h, h', Fig. 14; the projection then presses
on the extremity
of the lever mounted on the rod m, Fig. 12, which
frees the arm from the catch g, Fig. 20, and allows the spring
to close the valve. Immediately before this the projection i has pressed
the end of a lever which operates the plate of the orifice a, Figs.
11, 13, so as to keep open the latter against the resistance of a
spring during the time necessary for the penetration of the flame
into the cylinder A. V is the blower driven by the wheel tand. by
a band on the wheel s mounted on the shaft F of the turbine (Figs. 12,
13. R is the lever of the main cock of the apparatus.
This cock
has two ways, one communicating with the air conduit v, Fig. 13,
and the other (u) for the liquid fuel. Before reaching the orifice a
the air passes by the central cock Y, by which a certain quantity
may be allowed to escape at will. This cock is combined with a
graduated dial X and indicator by which the height of the flame
may be regulated. The plate of the flame port a is so arranged as
to close the tube v' at the same time as the said port, and to open
another orifice in the tube v' for the escape of the air.
The liquid
fuel is fed in the following manner-J (Figs. 11, 13) is the reservoir;
n the tube for the passage of the liquid to the feeder J'.
reservoir J is hermetically closed at the top and is provided with a
plate a little below the orifice of the tube n. o is a stop-cock,
which is closed when desired to fill the reservoir J.
freely from the top into the feeder J'. is a plate mounted a little
below the orifice q of the conduit n, the plates and t being of the
same height. The reservoir J being charged with liquid the latter
passes into J' up to the point a little above the orifice q.
flow will then be checked (the air being no longer able to pass into
the reservoir J by the pipe n) and will only commence anew when a
sufficient quantity of the liquid has been consumed to uncover the
The
The air penetrates
The

page_text: orifice q.
constant.
The level of the liquid fuel can thus be looked on as
From the feeder J' the liquid passes through the tube u,
Fig. 13, by the stop-cock R before arriving opposite the flame
orifice a, at which point is set a small lamp for the ignition of the
vapours generated by the air of the conduit v passing over the orifice
of the liquid tube u. To obtain from this apparatus the effects of
the pneumatic hydraulic ram, it will suffice to arrange within the
cylinder A, Fig. 2, a plate provided with a valve capable of closing
automatically when the water rises at its highest velocity, the result
being a blow, which as in the ordinary hydraulic ram may be utilised
for raising water to a considerable height. If so desired I may apply
to the propulsion of ships the rotation of a shaft produced in the
manner above indicated, but it will be more advantageous to effect
this propulsion by forcing out of the stern the water admitted at the
bow.
Figs. 16, 17, 18 represent an arrangement by which the water is
drawn through the bottom of the ship and forced out at the stern. In
these Figures A is the pneumatic cylinder, from which the air is
expelled by means of a certain number of flames, which enter by the
orifices a, a, a, u. is the valve, which with the orifices a is operated
in the manner already described. B, B', are the discharge conduits.
In the bottom of the cylinder A below these conduits is set a plate
(shown in section Fig. 17, provided with al certain number of
valves 5, 5, 8, 8.
Below these latter are mounted the pipes y, y, Fig. 18,
which pass through the hold of the vessel and issue into the water.
The discharge conduits B, B', may be hermetically closed at will by
means of the slides b', ". x, x', are two valves which allow the water
from the cylinder A to escape by B or B', while intercepting the passage
of the water from without. The safety openings ', ", Fig. 17, pierced
in the cylinder A, are hermetically closed by means of plates until
required for use in case of accident. These openings ', ", are con-
nected with the tube z in caoutchouc or other suitable material provided
with a perforated head T. In case of the vessel springing a leak the
conduit Z is thrown into the hold, and the opening being fitted with
a valve opening inwardly the water is drawn into the cylinder A, and
is from thence discharged into the sea by one of the conduits B or B'.
In this case the cylinders y, y, are closed by means of slides f, f.
Fig. 18, operated in any suitable manner. In case of fire the conduit Z

page_text: is directed towards the centre of combustion, the head T being
advantageously replaced by a suitable nozzle and the conduit " being
provided with a valve opening outwardly. The discharge pipes B, B',
being closed all the water drawn up by the cylinder A may be directed
against the flames. The conduit z may be divided into several
branches, so as to allow of the fire being acted on from different
directions. D is a water-tight box containing the cylinders y, y. This
box is so arranged that in the event of defective working of the
slides f, f. the water is prevented from passing into the ship. The
conduits B, B', may be fitted with moveable ends B" which allow of
the vessel being steered in the required direction. The blowing
apparatus may be operated by means of a small quantity of water
giving motion to a turbine or other suitable mechanism.
In Fig. 19 is represented a piston A' of the cylinder A from which
the air is expelled alternately above and below by a flame entering
at a on the principle already described. b', b", "", are the air outlet
orifices; c, e', are the discharge valves for the air when the flame
employed is too small to expel a sufficient quantity of air from the
cylinder; A" is the piston rod. The cylinder A is provided with a
casing containing water, but any other suitable cooling medium may
be employed.
It will be understood from the preceding description that my
Invention may be applied to all purposes requiring the employment
of motive power, the form, dimensions, and general details of con-
struction of the machines being varied according to their intended
application.
Having now described the nature of my said improvements, and the
manner in which the same may be carried into effect, I repeat that
I do not confine myself to the details of construction and arrangement
of apparatus herein laid down, as these are only given to illustrate
some of the modes of application of my Invention, and may obviously be
varied according to requirements without deviating from the principle
thereof as indicated by the elementary Figures 1, 2, of the Drawings;
but what I claim and desire to protect by Letters Patent is, the obtain-
ment of motive power by the atmospheric pressure resulting from a
vacuum formed by the expulsive action of flames on air contained in
a cylinder or other capacity, in manner and for the purposes sub-

page_text: stantially as herein specified and shewn in the Figures of the accompany-
ing Drawings.
In witness whereof, I, the said Johann Maximilian Plessner;
have hereto set my hand and seal, this Fifth day of September;
in the year of our Lord One thousand eight hundred and sixty-
eight.
J. M. PLESSNER. (L.s.)