IMPROVEMENTS IN DILATED AIR MOTIVE POWER ENGINES
Year: 1881

page_text: "
LETTERS PATENT to Paul Giffard, of Boulevard Saint-Denis, 1, at Paris, Civil
Engineer, for an Invention of IMPROVEMENTS IN DILATED AIR MOTIVE
POWER ENGINES."
PROVISIONAL SPECIFICATION left by the said Paul Giffard at the Office
of the Commissioners of Patents on the 11th February 1881.
PAUL GIFFARD, of Boulevard Saint-Denis, 1, at Paris, Civil Engineer.
"IMPROVEMENTS IN DILATED AIR MOTIVE POWER ENGINES."
.My Invention relates to improvements in thermic motors by dilated air under
pressure, and is distinguished from the heated air motors hitherto proposed, by the
special combination of the cylinder and piston. The great length given to these
parts relatively with the diameter permits of removing the herinetical or rubbing
joint from the fire, of bathing the rubbing wall of the cylinder in a cool liquid,
and so protecting the material forming the joint from the destructive action of the
heat.
.My Invention consists in the combination and use of a machine composed of a
cylindrical base of cast iron or other metal, which carries on an inner circular rib
the firegrate, under which is fitted a movable ash pan. On the upper edge of the
base is fastened the motive cylinder, enclosed towards the top by a trough con-
taining the refrigerating liquid, and cast with the cylinder, the bottom of which is
continued by a second cylinder or reheater of the same metal closed by a base
slightly bulged. This cylinder is fitted carefully under the first by a conical edge
joint and bolting. From the lower part of this cylinder reheater, which dips down
into the cylindrical base, open out the valves of admission and escape for the warm
motive air. Between the cylinder reheater and the grate the fire is enclosed by a
spiral tube, through which the air is conducted, as hereafter described. Sufficient
space is left between this tube and the bottom of the cylinder reheater for the
introduction of the fuel through an opening formed in a cast ring, which forms
a continuation of the fire space, and directs the gases of the fuel towards the sides
of the cylinder reheater'; this ring is secured to the interior of the cylindrical base
11

page_text: by flanges; finally, a second ring of cast or plate iron conducts the heated gases
towards the top of the cylinder reheater, whence they pass through a space between
the second ring and the holding down flange of the motive cylinder into the
chimney.
Below the flange of the cast ring or fire space above named the surrounding
wall of the cylindrical base is pierced with holes of about 6 centimeters in
diameter, which are of great importance for the heating or aeration of the room
which contains the motor. In operation, if the ash pan is opened at the proper
time, the surrounding air passing by the opening formed, part of it will be utilised
for the combustion, and the remainder superheated by contact with the outer wall
of the fire place will escape into the room through the said holes, thus forming an
efficient hot air stove. If, on the contrary, the ash pan be closed the admission of
air for combustion is made exclusively through the said holes, and the escape will
in that case be entirely by the chimney, an aeration of the workshop or room being
thereby the result.
In the interior of the motive and reheater cylinders is placed a plunger piston
cast hollow and carefully fitted with its rubbing joint or packing towards its
upper edge, that is to say, as far as possible from the fire.
The description of rubbing joint which I preferably employ is composed of a
circumferential groove or recess, in which is fitted a packing ring of semi hard
leather or india rubber, which ring is constantly kept against the inside of the cylinder
by a split steel spring ring placed in the groove at the back of the packing ring.
This joint only rubs along that portion of the cylinder cooled by the water from
the trough. The leather or india rubber cannot therefore be deteriorated under
the influence of the heat.
The plunger piston actuates a crank shaft by means of a connecting rod, this
shaft being mounted in bearings formed in side frames which are bolted on the top
of the cylinder trough; this is square, and has its surface between the side frames
pierced with four holes for filling up. At the bottom of the trough is fixed an
emptying cock. A driving pulley and fly wheel are keyed on the shaft.
On one side of the trough is bolted the compression pump, the piston of which
is worked by a connecting rod and a crank fixed at the end of the shaft.
This piston, which is fitted with an automatic joint of leather or india rubber,
forming also the admission valve for the air, plunges exactly to the bottom of the
body of the pump so that it leaves no injurious space.
The bottom of the cylinder of compression forms a valve for retaining the air,
and is composed of a disc of copper, very light, of larger diameter than the
cylinder, the bottom edge of which is rounded back so as to form a seat, against
which takes the disc under the pressure of a spiral spring at one side, and
that of the compressed air on the other side, the joint of the disc and of its seat
on the lower edge of the cylinder is formed by a ring of india rubber or leather fitted
into a groove on the disc, the course of which under the impulse of the compression
is limited by a circumferential projection formed on the cover to the lower chamber
of the pump. Under this cover is the tube for the introduction of the air, which
tube is connected with the spiral tube enclosing the fire in the cylindrical base. In
the wall of the lower chamber of the pump is fixed an excape cock, which permits
of stopping the machine by interrupting the introduction of compressed air.
manometer may also be fitted to the chamber.
A
The air compressed by the piston of this pump being raised to a high temperature
in its passage through the spiral tube enclosing the fire, acquires a strong
tension, and is introduced under the piston of the motive cylinder by the action of
an admission valve contained in a metal box fixed by conical entrance and by ears
and screws against the side of the cylinder reheater, the spiral tube conducting
the heated air opens into the lower part of this box, and is soldered into its.
cover.
The conical admission valve perfectly fitted to its seat is solid with its stem,
which is guided in a vertical column and at its upper part is pinned into a block.

page_text: "
LETTERS PATENT to Paul Giffard, of Boulevard Saint-Denis, 1, at Paris, Civil
Engineer, for an Invention of IMPROVEMENTS IN DILATED AIR MOTIVE
POWER ENGINES."
PROVISIONAL SPECIFICATION left by the said Paul Giffard at the Office
of the Commissioners of Patents on the 11th February 1881.
PAUL GIFFARD, of Boulevard Saint-Denis, 1, at Paris, Civil Engineer.
"IMPROVEMENTS IN DILATED AIR MOTIVE POWER ENGINES."
.My Invention relates to improvements in thermic motors by dilated air under
pressure, and is distinguished from the heated air motors hitherto proposed, by the
special combination of the cylinder and piston. The great length given to these
parts relatively with the diameter permits of removing the herinetical or rubbing
joint from the fire, of bathing the rubbing wall of the cylinder in a cool liquid,
and so protecting the material forming the joint from the destructive action of the
heat.
My Invention consists in the combination and use of a machine composed of a
cylindrical base of cast iron or other metal, which carries on an inner circular rib
the firegrate, under which is fitted a movable ash pan. On the upper edge of the
base is fastened the motive cylinder, enclosed towards the top by a trough con-
taining the refrigerating liquid, and cast with the cylinder, the bottom of which is
continued by a second cylinder or reheater of the same metal closed by a base
slightly bulged. This cylinder is fitted carefully under the first by a conical edge
joint and bolting. From the lower part of this cylinder reheater, which dips down
into the cylindrical base, open out the valves of admission and escape for the warın
motive air. Between the cylinder reheater and the grate the fire is enclosed by a
spiral tube, through which the air is conducted, as hereafter described. Sufficient
space is left between this tube and the bottom of the cylinder reheater for the
introduction of the fuel through an opening formed in a cast ring, which forms
a continuation of the fire space, and directs the gases of the fuel towards the sides
of the cylinder reheater'; this ring is secured to the interior of the cylindrical base

page_text: by flanges; finally, a second ring of cast or plate iron conducts the heated gases
towards the top of the cylinder reheater, whence they pass through a space between
the second ring and the holding down flange of the motive cylinder into the
chimney.
Below the flange of the cast ring or fire space above named the surrounding
wall of the cylindrical base is pierced with holes of about 6 centimeters in
diameter, which are of great importance for the heating or aeration of the room
which contains the motor. In operation, if the ash pan is opened at the proper
time, the surrounding air passing by the opening formed, part of it will be utilised
for the combustion, and the remainder superheated by contact with the outer wall
of the fire place will escape into the room through the said holes, thus forming an
efficient hot air stove. If, on the contrary, the ash pan be closed the admission of
air for combustion is made exclusively through the said holes, and the escape will
in that case be entirely by the chimney, an aeration of the workshop or room being
thereby the result.
In the interior of the motive and reheater cylinders is placed a plunger piston
cast hollow and carefully fitted with its rubbing joint or packing towards its
upper edge, that is to say, as far as possible from the fire.
The description of rubbing joint which I preferably employ is composed of a
circumferential groove or recess, in which is fitted a packing ring of semi hard
leather or india rubber, which ring is constantly kept against the inside of the cylinder
by a split steel spring ring placed in the groove at the back of the packing ring.
This joint only rubs along that portion of the cylinder cooled by the water from
the trough. The leather or india rubber cannot therefore be deteriorated under
the influence of the heat.
The plunger piston actuates a crank shaft by means of a connecting rod, this
shaft being mounted in bearings formed in side frames which are bolted on the top
of the cylinder trough; this is square, and has its surface between the side frames
pierced with four holes for filling up. At the bottom of the trough is fixed an
emptying cock. A driving pulley and fly wheel are keyed on the shaft.
On one side of the trough is bolted the compression pump, the piston of which
is worked by a connecting rod and a crank fixed at the end of the shaft.
This piston, which is fitted with an automatic joint of leather or india rubber,
forming also the admission valve for the air, plunges exactly to the bottom of the
body of the pump so that it leaves no injurious space.
The bottom of the cylinder of compression forms a valve for retaining the air,
and is composed of a disc of copper, very light, of larger diameter than the
cylinder, the bottom edge of which is rounded back so as to form a seat, against
which takes the disc under the pressure of a spiral spring at one side, and
that of the compressed air on the other side, the joint of the disc and of its seat
on the lower edge of the cylinder is formed by a ring of india rubber or leather fitted
into a groove on the disc, the course of which under the impulse of the compression
is limited by a circumferential projection formed on the cover to the lower chamber
of the pump. Under this cover is the tube for the introduction of the air, which
tube is connected with the spiral tube enclosing the fire in the cylindrical base. In
the wall of the lower chamber of the pump is fixed an excape cock, which permits
of stopping the machine by interrupting the introduction of compressed air. A
manometer may also be fitted to the chamber.
The air compressed by the piston of this pump being raised to a high temperature
in its passage through the spiral tube enclosing the fire, acquires a strong
tension, and is introduced under the piston of the motive cylinder by the action of
an admission valve contained in a metal box fixed by conical entrance and by ears
and screws against the side of the cylinder reheater, the spiral tube conducting
the heated air opens into the lower part of this box, and is soldered into its.
cover.
The conical admission valve perfectly fitted to its seat is solid with its stem,
which is guided in a vertical column and at its upper part is pinned into a block.

page_text: Under the latter acts a spiral spring, which normally solicits the valve onto its seat,
finally an eccentric or cam of suitable form is fixed on the shaft and set as required
for giving motion to the block, and so permitting the introduction of the motive
air under the piston, which in rising produces the rotation of the shaft.
The admission valve being closed again and the dilatation produced an escape
valve, constructed in a similar manner to that of admission, is opened by a second
cam. The columns of the admission and escape valves are screwed or otherwise
fixed onto their respective boxes, and the tightness of each ensured by the.
arrangement of its upper part, in which is lodged a spiral spring supported on a
metal ring or washer, which compresses another washer of india rubber or other
clastic material.
By another arrangement the bottom of the pump of compression contains both
the suction and compression valves. The suction valve is composed of a disc acted
upon by a supplementary cam on the shaft in combination with stems and an
oscillating lever.
According to a modified form of this machine for using superheated steam
concurrent with compressed air the fire grate is formed at its lower part with a very
resistant reservoir forming a boiler and provided with the usual safety fittings, a
pressure and water gauge. The inlet tube for the air from the compression pump
opens into this reservoir at its upper part, and another fixed on the top of the
boiler and rolled up in a spiral form round the upper part of the fire space is
connected with the admission valve. A charging hole is formed either above or
below this spiral. In this case the boiler is fed with water by means of the pipe
which directs the liquids onto the compression piston; this liquid will be afterwards
introduced to the reservoir with the air itself. An overflow pipe should also be
fitted.
In both arrangements of machine the dilated air passing by the escape passage
can either be used for heating the room by escaping freely, or through suitable
piping into it, or for increasing the draught by escape into the chimney. Finally,
it may be very advantageous to direct this air, heated again to a high temperature,
either pure or mixed with steam under the fire grate, when the heat drawn by the
gas will be thus recovered, and produce a marked acceleration of the combustion in
the fire, consequent possibly of burning the inferior combustibles.
The fire place may be arranged for the use of every kind of combustibles, solids,
liquids, or gases.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Paul Giffard in the Great Seal Patent Office on the 8th August
1881.
PAUL GIFFARD, of Boulevard Saint-Denis, 1, at Paris, Civil Engineer.
"IMPROVEMENTS IN DILATED AIR MOTIVE POWER ENGINES."
My Invention relates to improvements in thermic motors, actuated by air dilated
under pressure, and differs from the hot air motors hitherto devised by the special
combination of the cylinder and piston. The great length given to these parts
relatively to the diameter, permits of the hermetic joint being placed at a
considerable distance from the fire, and of the sides of the cylinder upon which
friction is exerted being bathed in a cooling liquid, the material forming the joint
being thereby protected from the destructive action of the heat.
The general type of my system is clearly illustrated in the annexed Drawings,
which shew on a scale of a specimen of an engine of about 25 kilogrammeters
power. The dimensions of the parts will vary according to the power to be
obtained..
Fig. 1 is a vertical section of the engine taken on a line passing through the-axes
of the motive cylinder and the pump.
Fig. 2 is a plan, the main shaft being removed.
Fig. 3 is a vertical section of the engine slightly modified for the simultaneous
use of air and superheated steam, Figs. 1, 2, 3 being on a scale of full size.
Fig. 4 is a view on 1/2 scale of the bottom of the pump, provided with inlet and
exhaust valves, and which can be employed instead of that shewn in Figs. 1 and 3.
Figs. 5, 6, 7, 8, & 9 are details of various parts, and are on a scale of .
An engine constructed according to my Invention consists of a cylindrical
base 8 of cast iron, provided with an inner circular rib, whereon are mounted the
fire-bars g, under which a moveable ash pan c is fitted.
On the upper edge of the said base is attached the motive cylinder m, surrounded
near its top by a reservoir b containing the cooling liquid, and cast in one piece
with the cylinder. The bottom of the motive cylinder is formed by a second
cylinder m (which I term a superheater) made of the same metal as the former and
closed by a slightly convex base. This cylinder is fitted carefully under the first by
a conical edge joint and bolting; at the lower part of this superbeating cylinder m
are provided the inlet and exhaust or outlet valves s and s¹ for the hot air which
furnishes the motive power.
Between the superheating cylinder and the fire-bars g is the fire box, which is
formed by the spiral or other suitably formed tube t, through which the air is
supplied, as hereinafter described. Sufficient space is left between this tube and
the bottom of the superheating cylinder m² for the introduction of the fuel through
a door p formed in a cast iron ring d, which forms a continuation of the fire box
and directs the gases of combustion towards the sides of the superheating cylinder;
this ring rests on a rib n cast on the interior of the cylindrical base; lastly, a
second ring d' of cast or sheet iron conducts the burnt gases towards the top of the
superheating cylinder, whence they pass through a space between the ring d¹ and
the flange of the motive cylinder m into the flue c.
Below the rib n the wall of the cylindrical base is pierced with holes o, o, of about
6 centimeters diameter, which are of very great importance for the heating or
ventilation of the locality in which the engine is placed. If the ashpan be opened
in cold weather, for instance, the surrounding air will pass through the opening thus
formed, a portion of it will be utilized for combustion, and the remainder will be
superheated by contact with the outside of the firebox, and will escape into the
4

page_text: locality through the holes o, o, thus an efficient hot air stove will be formed. In
summer, or in warm weather, however, the ashpan will be closed, and the admission
of air for combustion will be effected exclusively through the holes o, o, and its
escape will in that case take place through the chimney, and thus the locality in
which the engine is placed will be ventilated.
In the interior of the motive and superheating cylinders is placed a plunger
piston P, which is cast hollow, and has at its upper end a carefully fitted friction
joint or packing, that is to say, this joint is removed as far as possible from the
fire place. The joints which I prefer to employ are shewn 1/2 full size in Figs. 8
and 9, and in Fig. 1. Such a joint is constructed as follows:-
In a circumferential groove or recess is fitted a packing ring 7 of leather or semi
hard india rubber; this ring is constantly pressed against the inside of the cylinder
by a face spring or split steel spring ring placed in the groove inside the said
packing ring. This joint bears only against that portion of the cylinder m which
is cooled by the water from the reservoir b, the leather or india rubber cannot
therefore be deteriorated by the influence of the heat.
The plunger piston. P actuates a crank-shaft a by means of a connecting rod b¹;
this shaft is mounted in bearings f bolted to the reservoir b. This reservoir is
square, and is pierced with four holes for the purpose of filling. At the bottom of .
the reservoir I fit a waste cock, not shewn in the Drawings. A pulley p' and a
fly wheel V are keyed on the shaft. On one of the sides of the reservoir b is
bolted the compressing pump A, the piston P¹ of which is worked by a connecting
rod b and a crank h fixed at the end of the shaft a.
This piston is fitted with an automatic joint of leather or india rubber, the
packing of which forms the admission valve for the air; the down stroke of
the piston reaches exactly the bottom of the pump barrel, so that it leaves no
injurious space.
The bottom of the compressing pump or cylinder forms a retaining valve for the
air, and consists of a very light disc of copper i of larger diameter than the
cylinder, the bottom of which is rounded off so as to form a seat, against which
the disc impinges under the pressure of a spiral spring at one side, and that of
the compressed air on the other side. The joint of the disc and of its seat, and the
bottom of the pump or cylinder A, is formed by a ring of india rubber or leather
fitted in a groove in the disc. The course of this disc under the impulse of the
compression is limited by a circumferential projection formed on the cover i',
which closes the lower chamber of the pump. Under this cover opens the
air supply tube, which is coiled in the base s*, and forms the fire-box, as above.
stated; is an exhaust cock fitted in the wall of the lower chamber 22 of the
cylinder or pump, and by it the engine can be stopped by interrupting the
introduction of the compressed air. A pressure gauge may also be fitted in
the side of the chamber i².
The air compressed by the piston P being raised to a high temperature in its
passage through the spiral tube t acquires a strong tension, and is introduced under
the piston P by the action of the inlet valve, shewn in Fig. 5. This valve consists
of a metal box or casing s bevelled, and provided with screw threaded flanges or
projections, whereby it is fixed in the side of the superheating cylinder m²; the air
supply tube t opens into the lower part of this box, and is soldered into its closing
plate.
The conical admission valve 8 exactly fitted to its seat is made in one piece,
with its spindle 83 guided in a vertical column or pillar 8 (Fig. 7). At its upper'
part the spindle s³ is pinned into a block 85, under which is placed a spiral spring
constantly pressing the valve & against its seat. An eccentric s6, or a cam of.
suitable form, is mounted on the shaft a, and is so set as to cause the block so. to
descend at the proper time for causing the air (which furnishes the motive power)
to be admitted under the piston P, and the latter in rising causes the shaft a to'
rotate..
The admission valve being again closed and the dilatation or expansion produced->

page_text: the escape valve 8', Fig. 6, is opened by a second cam s' acting on parts substan-
tially similar to the inlet devices. The columns 8 are screwed or otherwise fixed
on the boxes 8, 8, and the tightness of each ensured by the arrangement of its
upper part, in which is fitted a spiral spring ² supported on a metal disc or washer,
which forms a stuffing box and compresses another washer of india rubber or
other elastic material.
Figure 4 shews a compressing pump, the bottom of which contains both the
suction and delivery valves. The delivery valve is similar to that shewn at i, as
above described, and is formed by the bottom of the pump barrel; the suction
valve consists of a disc fitted in the bottom, and actuated by a supplementary
cam on the shaft a, which cam acts on the valve by means of connecting rods and
an oscillating lever.
Figure 3 shews in section a modified form of the engine shewn in Fig. 1; this
modification of my engine is so constructed as to allow superheated steam to be
used together with the compressed air. For this purpose the fire box is formed at
its lower part with a reservoir k capable of bearing considerable pressure, and this
forms a boiler, the usual safety devices, pressure gauge, and water level being
provided. The supply tube t opens into the reservoir, and another tube t¹
fixed on the top of the boiler and coiled around the upper part of the fire-
space is connected with the inlet-valve s. A charging hole p is formed either
above or below this coiled tube. In this arrangement the boiler is fed with water
through the pipe g, which delivers the liquid on to the compressing piston, whence
the same is introduced into the reservoir together with the air. An overflow
pipe q' may also be provided.
In both arrangements of engine the dilated or expanded air passing through the
exhaust passage u can either be used for heating the locality in which the engine
is placed by allowing said air to escape freely, or by conducting it through suitable
pipes, or the air may be caused to increase the draught by escaping into the
chimney. Lastly, it may be very advantageous to direct this air, which still retains
its high temperature (whether it be pure or mixed with steam), under the fire-
bars. The heat contained in the gas will thus be recovered, and will considerably
increase the combustion in the fire-box, which allows fuel of very inferior quality
to be advantageously used.
The firebox may be constructed of metal or brick, and arranged for the use of
every kind of fuel, whether solid, liquid, or gaseous, according to the particular
purpose the engine is to serve. The box-may also be isolated from the engine if
desired, and provided with communicating tubes.
Fig. 8 shews an arrangement of joint placed at the upper part of the motive
piston; Fig. 9 shews a fixed joint placed on the top plate of the motive cylinder of
the engine, the piston in this case being smooth. The Drawings sufficiently
indicate the mode of fixing the india rubber or leather packing rings l.
I may vary the form, materials, dimensions, and relative arrangement of the
parts of this engine, as may be required, to suit various conditions of working.
And having now described the nature of my said Invention, and the manner in
which the same may be performed, I declare that I claim,-
1. An engine actuated by compressed and heated air, and consisting of a
compressing pump P¹, a superheating fire-place or fire box, formed partly by the
air inlet pipe t (of spiral or other suitable form), of the inlet and outlet valves s
and s', actuated by cams or eccentrics, of a motive piston P of considerable length
allowing the hermetic joint to be placed at a distance from the source of heat, said
piston operating in a cylinder provided with a reservoir for containing cooling
liquid, all substantially as herein described and shewn in the Drawings.
2. The adaptation to such an engine of a boiler k with the usual feed and safety
fittings for the purpose of simultaneously employing air and superheated steam, as
described and shewn.
3. The special construction of the inlet valve s and of the outlet valve 8' (Figs. 5.
R-61
na desanibed

page_text: 4. The combination and employment of packing joints fitted in the upper flange
of the piston and provided with face springs or spring rings (Fig. 1), or fitted in
the top plate of the motive cylinder of the engine.
5. The above described construction of the firebox (made of any suitable material,
metal, or brick) either combined with the parts constituting the engine or isolated
therefrom, and provided with communicating tubes, said firebox being adapted for
use with any kind of fuel, whether solids, liquids, or gases, and also provided with
means for the the injection of the waste gases into the firebox for the recovery of
the heat, all substantially in the manner set forth.
In witness whereof, I, the said Paul Giffard, have hereunto set my hand
and seal, this Twenty eighth day of July, in the year 1881.
Witness,
ALBERT CAHEN,
Civil Engineer.
Of Boulevard Saint Denis, 1,
at Paris.
PAUL GIFFARD.
(L.S.)