IMPROVEMENTS IN HEATED AIR MOTORS
Year: 1874

page_text: LETTERS PATENT to Robert Gottheil, of the International Patent
Office, at 126, Linden Str., Berlin, Prussia, Engineer, for the Inven-
tion of "IMPROVEMENTS IN HEATED AIR MOTORS."-A communication
by the Berlin Anhalt Machine Manufacturing Company, at Berlin
and Dessau. Germany.
Sealed the 3rd July 1874, and dated the 4th May 1874.
* PROVISIONAL SPECIFICATION left by the said Robert Gottheil at the
Office of the Commissioners of Patents, with his Petition, on the
4th May 1874.
I, ROBERT GOTTHEIL, of the International Patent Office, at 126,
Linden Str., Berlin, Prussia, Engineer, do hereby declare the nature of
the said Invention for “IMPROVEMENTS IN HEATED AIR MOTORS," to be as
follows:-
This Invention relates to the construction and operation of motors of
the kind wherein a piston acted on by the alternate expansion and con-
O traction of air due to changes of temperature is connected to a crank on
a shaft so as to give rotary movement thereto,
:

page_text: The improved engine or motor is constructed as follows:-A horizontal
cylinder is made in two parts. The front part is kept cool by the circu-
lation of water through a jacket in which it is enclosed. The hinder
part is kept hot by being set in the flues of a furnace, where the products
of combustion circulate round it. The front part, which is open at the
end, is fitted with a piston packed with a cup leather, which allows air
to pass the piston in the one direction, but prevents its passage in the
other direction. Behind the piston is a long hollow plunger of sheet
metal divided by partitions into two or more compartments, which
plunger can work with a little clearance within the cylinder, being guided
therein by side guides and having its weight supported by a roller. The
piston has two rods connected to arms on a rocking shaft, another arm
from which is connected by a connecting rod to a crank on a shaft
carrying a heavy fly wheel. The plunger has a rod passing through a
stuffing box in the piston, and jointed to an arm on another rocking
shaft, which has an arm connected to another crank on the fly wheel
shaft, the latter crank being set on the shaft at an angle to the former
crank. By these connections when the fly wheel is turned both the
piston and the plunger are caused to travel to and fro in the cylinder,
but they are differently timed in their respective strokes by the difference
of position of their respective cranks. When the plunger is moved
towards the heated end of the cylinder it displaces the air which has
been expanded by the heat, and causes it to flow past the plunger to
the cool front portion of the cylinder. The air thus cooled becomes
reduced in volume and pressure, and the pressure on the inner face of
the piston is thus diminished. When on the other hand the plunger is
moved forwards the cold air which was in the space in front of it between
it and the piston is displaced and caused to flow past the plunger to the
hot end of the cylinder, where its volume and pressure are increased,
thereby increasing the pressure on the inner face of the piston. The
changes of pressure thus effected on the piston by the proper timing of
its strokes in relation to those of the plunger are utilised to give motive
power to the crank shaft through the connections above described, and
the crank shaft being thus by a succession of impulses caused to revolve
gives the required movements to the plunger, the fly wheel rendering
the speed of revolution uniform or nearly so.
In first starting the engine the fly wheel is turned by hand, and a
certain quantity of air enters the cylinder past the cup leather of the

page_text: piston, and as the cup leather prevents the passage of air outwards the
air within the cylinder is retained therein, exerting always a pressure
equal to or greater than that of the external atmosphere, but rendered
by the heat always greater during the outstroke of the piston than during
its instroke, so that the driving impulse is communicated to the fly wheel
at every outstroke, and the instroke of the piston is effected by the
momentum of the fly wheel. A cock is provided on the piston, which
can be opened when desired to admit air to and allow surplus air to
escape from the cylinder.
The furnace employed in connection with this engine consists of an
upright fuel chamber above a fire-grate, with a feeding door at the top
of the chamber and a water tank in the ash-pit below the grate, so that.
the vapour of the water may keep the fire-grate cool. The fuel chamber.
may be of such dimensions as to hold a supply of fuel sufficient to last.
for several hours. From the side of the chamber a little above the fire-
grate a sloping flue provided with a hole for the supply of air leads to a
chamber in which is enclosed the hot end of the cylinder, and suitable.
partitions are arranged in this chamber to cause the hot products of
combustion to circulate round the cylinder, which products finally issue
by a chimney provided with a valve or damper to regulate the draught..
The flues are provided with suitable cleaning doors and eye holes to.
observe the heating of the cylinder.
,
A friction brake is provided, which can be applied to the rim of the
fly wheel for the purpose of stopping the engine, and this brake is con-
nected to a governor so that when the velocity of the engine tends to
increase the brake is applied by the governor with more or less force so.
as to reduce the speed. This brake consists of a brake block on a lever,
which rests on a cam or eccentric, connected by a rod to a lever, acted
on by the governor in such manner that when the governor balls expand
the cam or eccentric is turned so as to raise the brake against the rim of
the fly wheel. This rim is made somewhat eccentric, so that at one part
of the revolution there is little or no resistance to the raising of the
brake by means of the governor, but the brake thus raised acts when
the full part of the wheel comes round to cause retardation.
The circulation of water through the jacket of the cool end of the

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Gottheil in the Great Seal Patent Office
on the 28th October 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
GOTTHEIL, of the International Patent Office, at 126, Linden St., Berlin,.
Prussia, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourth day of May, in the year of our
Lord One thousand eight hundred and seventy-four, in the thirty-seventh
year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Robert Gottheil, Her special license
that I, the said Robert Gottheil, my executors, administrators, and
assigns, or such others as I, the said Robert Gottheil, 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
HEATED AIR MOTORS," a communication to me by the Berlin Anhalt Machine
Manufacturing Company, at Berlin and Dessau, Germany, upon the
condition (amongst others) that I, the said Robert Gottheil, my executors
or administrators, by an 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 Robert Gottheil, 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, reference being had to the accompanying
Sheet of Drawings and to the figures and letters marked thereon, that
is to say:-
This Invention relates to the construction and operation of motors of
the kind wherein a piston acted on by the alternate expansion and con-
traction of air due to changes of temperature is connected to a crank on
a shaft so as to give rotary motion thereto.

page_text: The improved engine or motor is constructed as follows:-A horizontal
cylinder is made in two parts. The front part is kept cool by the circu-
lation of water through a jacket in which it is enclosed. The hinder
part is kept hot by being set in the flues of a furnace, where the products
of combustion circulate round it. The front part, which is open at the
end, is fitted with a piston packed with a cup leather, which allows air
to pass the piston in the one direction, but prevents its passage in the
other direction. Behind the piston is a long hollow plunger of sheet
metal divided by partitions into two or more compartments, which
plunger can work with a little clearance within the cylinder, being
guided therein by side guides and having its weight supported by a roller.
The piston has two rods connected to arms on a rocking shaft, another
arm from which is connected by a connecting rod to a crank on a shaft
carrying a heavy fly wheel. The plunger has a rod passing through a
stuffing box in the piston and jointed to an arm on another rocking shaft,
which has an arm connected to another crank on the fly wheel shaft, the
latter crank being set on the shaft at an angle to the former crank. By
these connections when the fly wheel is turned both the piston and the
plunger are caused to travel to and fro in the cylinder, but they are
differently timed in their respective strokes by the difference of position of
their respective cranks. When the plunger is moved towards the heated
end of the cylinder it displaces the air which has been expanded by the
heat and causes it to flow past the plunger to the cool front portion of the
cylinder. The air thus cooled becomes reduced in volume and pressure,
and the pressure on the inner face of the piston is thus diminished.
When on the other hand the plunger is moved forwards the cold air
which was in the space in front of it between it and the piston is dis-
placed and caused to flow past the plunger to the hot end of the cylinder,
where its volume and pressure are increased, thereby increasing the
pressure on the inner face of the piston. The changes of pressure thus
effected on the piston by the proper timing of its strokes in relation to
those of the plunger are utilised to give motive power to the crank shaft
through the connections above described, and the crank shaft being thus
by a succession of impulses caused to revolve gives the required move-
ments to the plunger, the fly wheel rendering the speed of revolution
uniform or poorly So

page_text: piston, and as the cup leather prevents the passage of air outwards the
air within the cylinder is retained, therein exerting always a pressure
equal to or greater than that of the external atmosphere, but rendered
by the heat always greater during the outstroke of the piston than
during its instroke, so that the driving impulse is communicated to the
fly wheel at every outstroke, and the instroke of the piston is effected by
the momentum of the fly wheel. A cock is provided on the piston,
which can be opened when desired to admit air to and allow surplus air
to escape from the cylinder.
The furnace employed in connection with this engine consists of au
upright fuel chamber above a fire-grate with a feeding door at the top
of the chamber and a water tank in the ash-pit below the grate, so that
the vapour of the water may keep the fire-grate cool. The fuel chamber
may be of such dimensions as to hold a supply of fuel sufficient to last
for several hours. From the side of the chamber a little above the fire-
grate a sloping flue provided with a hole for the supply of air leads to a
chamber in which is enclosed the hot end of the cylinder, and suitable
partitions are arranged in this chamber to cause the hot products of
combustion to circulate round the cylinder, which products finally issue
by a chimney provided with a valve or damper to regulate the draught.
The flues are provided with suitable cleaning doors and eye holes to
observe the heating of the cylinder.
A friction brake is provided, which can be applied to the rim of the
fly wheel for the purpose of stopping the engine, and this brake is con-
nected to a governor so that when the velocity of the engine tends to
increase the brake is applied by the governor with more or less force so
as to reduce the speed. This brake consists of a brake block on a lever
which rests on a cam or eccentric, connected by a rod to a lever, acted
on by the governor in such manner that when the governor balls expand
the cam or eccentric is turned so as to raise the brake against the rim of
the fly wheel. This rim is made somewhat eccentric, so that at one part
of the revolution there is little or no resistance to the raising of the
brake by means of the governor, but the brake thus raised acts when
the full part of the wheel comes round to cause retardation.
The circulation of water through the jacket of the cool end of the
cylinder is maintained by a pump worked from the crank shaft or from
one of the rocking shaft arms.

page_text: DESCRIPTION
IDE
Fig. 1 represents à longitudinal section; Fig. 2, a plan partly in
section; Fig. 3, an end view; and Fig. 4, a part plan of an engine or
heated air motor constructed according to this Invention; and Fig. 5
represents a transverse section through the cylinder at V2, Fig. 1.
A is the front part of the horizontal open ended cylinder fitted with a
piston. M and enclosed in a water jacket C¹. The back part of the
cylinder B is enclosed in a flue heated from a furnace. The furnace
consists of a chamber S, S, supplied with fuel by a side door D. The
fuel rests on a grate R, which is kept cool by vapour from water in a
tank U placed in the ash-pit. The chamber S, S, holds a charge of fuel
sufficient for several hours' working. The products of combustion pass
by an inclined fluc, into which opens a pipe J for the supply of additional
air into the flue chamber containing the cylinder. A lump E protects
the end of the cylinder from the direct impact of the flame, and a lump
H serves to support the cylinder. A bridge F deflects the products of
combustion so that they are made to circulate round the cylinder, as
indicated by the arrows, finally escaping by a chimney provided with a
throttle valve or damper G. A door K is provided for clearing off the
fine ash that may lodge on the cylinder, and in this door is an eye hole
through which the heating of the cylinder can be observed, it being
raised to a red heat for working. A pocket T communicates with the
exterior by a side door for removal of ash..
The piston M is connected by two rods N, N, to arms on a rocking
shaft O', which has an arm connected by a connecting rod P to a
crank Q on the engine shaft C, on which is a heavy fly wheel S¹. The
packing of the piston M is effected by a cup leather, which acts as a
valve, allowing air to pass into the cylinder from the exterior atmo-
sphere, but preventing the issue of air from the cylinder. A cock a on
the piston may be opened to allow free passage of air when the engine
is moved by hand. The plunger divided in several air compartments
V₁, V2, V3, V₁, is connected by a rod W passing through a stuffing box in
the piston M to arms X on a rocking shaft X', which has an arm X²
connected by a connecting rod Z to a crank Z' on the shaft C, this crank
being set on the shaft in advance of the crank Q, with which the piston
is connected. The plunger is somewhat smaller in diameter than the
cylinder B in which it works, so that there is a thin annular passage for

page_text: .
air between it and the interior of the cylinder. It is guided laterally in
its movement by guide rails d, d, and its weight is supported on a
roller which is free to roll on a rail c¹ mounted in a recess at the lower
side of the cylinder B. The governor worked by bevel gear 9 from the
shaft C is so arranged that when its balls k, k, expand in consequence of
increased speed they depress the spindle i so as to move downwards a
bent lever k. An arm / moving with this lever is connected by a rod m
to an eccentric segment n, on which rests a lover o having fixed on it a
brake block q. The periphery of the fly wheel S¹ is made a little
eccentric, so that when the governor balls k, k, expand they can move
the eccentric segment n and so raise the lever o and cause the brake q
to bear against the periphery of the fly wheel while that part which has
least raidius is passing the brake, and the brake being thus raised serves
to retard or arrest the revolution of the fly wheel when the full part of
the periphery comes to face the brake. The eccentric segment n has a
socket arm w for the reception of a lever, whereby the eccentric can be
moved by hand so as to apply the brake and stop the engine. The water
jacket C¹ surrounding the cylinder A may be supplied from a cistern or
by a pump y, which may be worked by a rod from the arm X, the
heated water being discharged from the upper part of the jacket by an
opening z.
From the construction described above it will be seen that the fly
wheel revolving in the direction of the arrow when the piston M is at
the extreme of its outstroke, as shewn in Fig. 1, the displacing plunger
owing to the advance of its crank Z' is already moving backwards and
displacing the air from the hot end of B. The air so displaced passing
the plunger towards the cool end of the cylinder has its temperature and
pressure reduced so that the piston makes its instroke under diminished
pressure. When it has completed its instroke, the plunger having
already begun to advance towards the front displaces the air between it
and the piston, and this air passing the plunger to the hot end of B has
its temperature and pressure raised so as to cause the piston to make its
outstroke under increased pressure. As the packing of the piston acts
as an admission valve for air the pressure during the instroke of the
piston is not reduced below that of the external atmosphere, but as the
air which enters the cylinder past the packing cannot escape the pressure
of the heated air during the outstroke of the piston considerably exceeds
that of the external atmosphere and acts as the driving force which is

page_text: stored up by the momentum of the fly wheel. The several compart-
ments of the plunger divide it into zones of different temperatures, that
next the piston being the coldest, and the air which presses on the piston
and comes in contact with the front working portion of the cylinder is
comparatively cool, acting merely as a medium for transmitting to the.
piston the increased pressure of the heated air behind..
Having thus described the nature of this Invention and in what
manner the same is to be performed, as communicated to me by my
correspondents, I claim,-
First. The construction of a heated air motor engine, substantially as
herein described, such engine having an open ended cylinder, the front
part of which is kept cool and fitted with a piston packed so as to admit
air from the exterior, and the back part of which is kept hot and
provided with an air displacing plunger, the piston and the plunger
being respectively connected to cranks so set on one fly wheel shaft that
the plunger is made to transfer the admitted air alternately to the hot
and the cold part of the cylinder, while the piston being subjected to
the changes of pressure resulting from the altered temperature of the
air imparts rotary motion to the shaft.
Second. In a motor engine of the kind referred to above the construc-
tion of the furnace and flues for heating the cylinder, the furnace
consisting of a fire-grate surmounted by a fuel chamber communicating
with a chamber in which the hot part of the cylinder is enclosed, and in
which the products of combustion are caused to circulate about the
cylinder, substantially as herein described.
Third. Forming the displacing plunger of a motor engine of the kind
above referred to in several compartments, and guiding and supporting
the same during its to-and-fro movement, substantially as herein de-
scribed.
Fourth. The construction and arrangement of the connections from
the piston and plunger of the motor engine referred to above to their
respective cranks, such connections consisting of rocking shafts with
arms connected respectively to the piston and plunger and to their
cranks, substantially as herein described.
Fifth. In the motor engine referred to above the arrangement of the
governor and brake, operating in combination with a slight eccentricity

page_text: of the fly wheel for the purpose of regulating the speed, substantially as
herein described.
In witness whereof, I, the said Robert Gottheil, have hereunto
→
set my hand and seal, this Twentieth day of October, in the
year. of our Lord One thousand eight hundred and seventy-
four.