IMPROVEMENTS IN HOT-AIR ENGINES
Year: 1881

page_text: LETTERS PATENT to Arnold Edmund Robinson and Horace Robinson, both of
Manchester, in the County of Lancaster, for an Invention of "IMPROVEMENTS
IN HOT-AIR ENGINES."
PROVISIONAL SPECIFICATION left by the said Arnold Edmund Robinson
and Horace Robinson at the Office of the Commissioners of Patents on the
18th November 1881.
ARNOLD EDMUND ROBINSON and HORACE ROBINSON, both of Manchester, in the
County of Lancaster. "IMPROVEMENTS IN HOT AIR ENGINES."
Our Invention relates to that class of air engines in which the air is alternately
heated and cooled, and the consequent expansion and contraction and variation of
pressure is utilized to produce motive power.
We construct our engine with a vessel or cylinder opened at one end, and formed
of suitable metal, such as iron. The part nearer the open end is cooled preferably
by means of a water jacket or tank surrounding it, whilst the part nearer the closed
end is made of a larger internal diameter, and is lined internally with fireclay,
plumbago, or other material being a good non-conductor of heat. The internal
diameter of the said lining is equal to or slightly larger than the internal diameter
of the cooled part of the cylinder, thus forming a continuation of it.
The lined portion of the cylinder or vessel is closed by an end or boater,
preferably of an egg ended form or of a partly hollow cylindrical form, with an egg
end which extends into the lined part of the cylinder, but leaving a space between
the heater and the said lining; this space constitutes part of the heating chamber.
The heater is formed separately, and is bolted to the chamber or cylinder with a
ring of asbestos or other good non-conductor of heat interposed.
The aforesaid enlarged lined portion of the chamber or cylinder may be formed
separately, and attached to the cooled portion of the cylinder. The object of the
aforesaid lining of non-conductor is to more effectually confine the heat within the
heating chamber, and so that heat shall not readily be transferred to the metal
cylinder.
The position of the non-conductor also better separates the heater from the cooled
end of the cylinder.
The heater is heated by means of a Blame or fire within it in the manner described
hereafter, and the heat is transmitted through it to the air within the lined portion
of the cylinder or chamber.
The beater being of the form already described, the pressure within the cylindor

page_text: subjects the material of the heater to compression; the heater may with safety be
made thinner than if it were subject to strains of tension; thus heat is easily
conducted into the heating chamber. Another advantage of this form of heater is
that it can be carried into the heating chamber within the internal diameter of the
aforesaid lining of non-conductor.
The working piston operates within the aforesaid cooled end of cylinder or
vessel, and a displacing pistion combined with a moving regenerator also works
partially within the cool end of said cylinder and partially within the before-
mentioned lined portion of the cylinder or chamber in the manner described
hereafter.
The working piston is constructed of metal, and is made preferably of con-
siderable length. On the external diameter may be formed a groove, within which
is placed sponge or cotton wick, or other suitable material for taking up and
distributing the oil in the sides of the cylinder. At the inner end of the piston a
junk ring is fitted for the purpose of adjusting the main cup leather (turned
inward), which leather works against the sides of the cylinder. A second junk
ring of smaller diameter is fitted to the piston to adjust a small cup leather in the
working position, through which works the displacer rod, or a gland may be sub-
stituted. Within the hollow portion of the working piston are formed two bosses
projecting inward. The piston is connected to the crank shaft by means of a
connecting rod, the end of which connected to the piston is formed as a ring with two
bosses thereon, which bosses fit between the aforesaid two bosses in the piston; the
Raid connecting rod is continued from one side of the ring. A pin on each side is
fitted through each of the said bosses on the piston into each of the bosses on the
ring of the connecting rod, so that tho connecting rod is free to oscillate; the other
end of the connecting rod is connected to one crank of a two throw crank shaft.
The mode of attaching the working piston connecting rod to the working piston
by means of the ring on the connecting rod and bosses on the piston is for the
'purpose of relieving the working piston from undue side strain, and also to allow
the displacer rod and the displacer connecting rod to be connected to the crank
shaft conveniently.
The said crank shaft is made preferably with two cranks set at about an angle of
90 degrees; and as it is desirable to have the crank pins as close to one another as
possible they are connected together by a single sheaf or link.
The displacer rod, which is brought through the small cup leather or gland in
the working piston, is connected to the other crank pin by means of the displacer
connecting rod. The displacer rod is formed with an enlargement or boss upon it
outside or beyond the cup leather, and the said rod is carried up through a guide.
A pin is fixed tightly to the small end of the displacer connecting rod, and is free
to work in the boss in the displacer rod. The displacer rod and the small end of
displacer connecting rod can work through the ring end of the working piston
connecting rod. The object of this arrangement of connecting gear is to get a
compact and as direct a connection as possible without imposing undue side
strain.
The combined displacer and regenerator is constructed preferably in the following
manner-A metal cap or piston is made to form the end of the said displacer
furthest away from the heater. The displacer rod is attached thereto. This cap
or piston works within the working cylinder. The outer part of the said cap or
piston is of smaller diameter than the cylinder, and has holes formed through its
sides in such a manner that the air pressing out through them from the regenerator
shall be projected against the cool sides of the cylinder. The said cap or piston is
enlarged near its inner end to fit the working cylinder, and a groove may be turned
upon it, within which is placed sponge, or wick, or suitable material to take up and
distribute the oil on the sides of the cylinder. A cylinder, preferably of thin sheet
metal, is attached to the aforesaid cap, and is of such a diameter that it works near
to the non-conducting lining of the heating chamber aforesaid, but leaves a space
between the aforesaid lining and the sides of the said cylinder of thin metal. This

page_text: cylinder of thin metal is carried to such a length that when the said combined
displacer and regenerator is at the extremity of its inward stroke, the thin sheet
metal shall be interposed between the non-conducting lining of the heated chamber
or cylinder and the heater, leaving an annular shaped passage on either side of the
said thin metal.
A cap of cast iron or other suitable material is attached within the said thin
metal cylinder in such a po-ition that when the displacer is at the end of its
inward stroke the said cap shall nearly touch the egg ended part of the heater.
Holes are formed in the thin metal cylinder of the displacer near to the part where
the said cap is attached. These holes are for the purpose of allowing the air to
pass from the regenerator to the outside of the said thin metal cylinder. The
aforesaid cap is formed so that it follows the lines or form of the egg end of the
heater. Webs are cast in the cap which support an annular or hollow shaped piece
of material (being a good non-conductor of heat) within the said thin metal
cylinder; this non-conducting material extends to or nearly to the outer cap or
piston alrealy described. Within the inner diameter of the said non-conductor is
placed the regenerator of wire gauze or other suitable material presenting a large
surface.
At the end of the said non-conductor furthest away from the heater is placed a
ring, and at the same end of the regenerator is placed another ring. These rings
aro just within the outer cap or piston of the displacer, and several screws are
placed in the said outer cup bearing on each of the said rings for the purpose of
adjusting the said non-conductor and regenerator, the aforesaid non-conductor
bearing against the said webs or projections of the inner cap with a metal ring
interposed, and the regenerator bearing against the inner
cap:
The heating apparatus is constructed preferably in the following manner :-
Round the chimney which carries away the products of combustion of the flame
or fire is placed a tube or casing of larger diameter or size than the chimney. This
space or passage leads to a chamber or fire box beneath the heater, which chamber
may be lined with a material which is a good non-conductor of heat, such as fireclay
or cement. The top of the said chamber or fire box consists of a diaphragm formed
with a tubular extension or uptake upon or attached to it. This tube or uptake
extends towards the apex of the heater, and being of smaller diameter or size than
the heater a space is left between it and the heater. This space leads to an annular
space opening into the chimney.
When gas is used to heat the apparatus we prefer to use a Bunsen burner within
the closed chamber or fire box. In the side of the chamber is formed an opening
through which the burner can be withdrawn from the chamber for lighting and
inspection, and replaced. A cover or lid for the opening is formed upon or attached
to the pipe or burner. This lid or cover is larger than the hole or opening in the
chamber. When the burner is in its proper position for use the lid or cover at its
lower side drops in between a stop and the lip of the opening, and the weight of
the burner within the chamber causes the upper part of the lid to bear against the
lip or opening, thus closing it.
We do not confine ourselves to gas for heating the apparatus, as liquid or solid
fuel may be used. When liquid fuel is used, such as petroleum or other hydrocarbon,
the flame of the lamp is used in the chamber or fire box in place of the Bunsen
burner.
When coal or other solid fuel is used, the chamber or fire box is made deeper,
and fire bars are provided within it. The heated air from the space around the
chimney is in this case brought into that part of the chainber below the fire bars,
which part of the chamber acts us an ash box; or air may be brought in direct
from the atmosphere into this part of the chamber without being drawn down the
space around the chimney.
The action of the engine is as follows:-
The heater is heated by means of the gas flame or fire in the chamber or fire
box, the flame being supplied with air, heated by being drawn through the space

page_text: formed around the chimney as already described, the flame or heated products of
combustion pass through the tube or uptake before mentioned, and come into
contact with the heater, and are carried or drawn down the sides of the heater to
the annular space leading to the chimney up which they escape.
The air within the heated chamber is heated, and the expansion drives the
working piston outward. This actuates the crank shaft, and rather before the
working piston has reached the outer extremity of its stroke the crank shaft
causes the combined displacer and regenerator to commence its travel from the cool
portion of the cylinder to the heated chamber. The air from the heated end or
chamber passes between the sides of the heater and the inner sides of the lower
portion of the thin metal cylinder, forming part of the displacer, then passes up
part way along between the outer side of said thin metal cylinder and the inner
side of the non-conductor of the heated chamber, then through the holes or
openings through the thin metal cylinder near to the inner cap of the displacer to
the regenerator of wire gauze or other suitable material contained within the
displacer. The air then passes through the said regenerator, giving up a portion of
its heat to the regenerator, and passes out considerably cooled through the holes or
openings in the outer cup of the displacer. The air rushes through the said holes
against the cooled sides of the working cylinder and is further cooled. The
consequent contraction reduces the pressure in the cylinder and allows the working
piston to descend, continuing the motion of the crank shaft, and rather before the
working piston has reached the extremity of its inward stroke causes the displacer
to commence its outward stroke. This causes the cool air to rush through the
holes in the outer cap of the combined displacer and regenerator into and through
the regenerator. Part of the heat previously left in the regenerator is now taken
up by the air in its passage, and the air which is thus partially heated passes over
the inner cap and is further heated, then passes out through the holes or openings
in the thin metal cylinder of the displacer and flows between the outer sides of the
thin metal cylinder and the non-conductor of the heated chamber. The air then
passes between the inner sides of the thin metal cylindrical portion of the displacer
and the heater, and is thus heated, the consequent expansion of the air forcing the
working piston outward. Motive power is thus obtained.
The crank actuating the displacer is set so as to move the displacer in advance of
the working piston.
In place of the double crank with one intermediate sheaf or link and connections
as described, we may connect the working piston by an ordinary connecting rod to
one crank or disc. A pin attached to another disc or crank or to the fly
wheel actuates the combined displacer and regenerator through the following
connections:-
A rocking arm or lever is provided which oscillates or works within the
aforesaid chamber or cylinder and a recess formed in the side of the said chamber
or cylinder. The combined displacer and regenerator is suitably connected to the
end of this arm or lever, and the other end of said arm or lever is attached to
a.rocking shaft, which rocking shaft is carried out through a cup leather or suitable
packing. Another arm or lever is attached outside to the said rocking shaft, and
this arm or lever is connected by a rod to the aforesaid crank or disc pin or pin
in the fly wheel.
In come cases, as for instance, where the engine is required for pumping, we
may invert the engine, the heated end being then uppermost, and we may connect
the piston to the working crank by means of a rod extending outward, which rod
at or about its extremity furthest away from the piston is suitably guided, and a
connecting rod is jointed to it. This connecting rod extends back to the crank pin.
An oil cup of an annular trough or channel form is attached to the open end of the
cylinder when this end is downward, and a lip or ring may be forined upon the
piston which dips into oil within this oil cup, and carries the oil up the sides of
the cylinder to lubricate it. Sponge, or wick, or other suitable material may be laid
in this oil cup and the oil will be prevented from splashing..

page_text: Where the engine is required to work a pump the pump may act as a guide for
the piston rod, which rod extends downward and is attached directly to the pump.
The piston in this case works directly on to the pump, and the weight of the piston
and its connections will to a certain extent balance the column of water or other
fluid. In engines with the open end of chamber or cylinder downward and the
heater uppermost, we prefer to use gaseous or liquid fuel, and the heating apparatus
may be arranged substantially in the same manner as already described, but will
be inverted, and the burner may be inserted from the top instead of from the side.
Or a ring or annular burner may be used, and in this case the products of
combustion and heat of the flame are drawn over and into the heater and up
through a tube which projects down towards the end of the heater and conducts
the products of combustion to the chimney.
A cover of fireclay or other non-conducting refractory material is provided to
prevent or lessen the radiation of heat.
The speed of the engine may be governed in the following manner:-A small
valve at certain times opens communication between the enclosed air within the
chamber or cylinder and the outside air. A centrifugal governor, which may be
substantially of the form described hereafter, is driven from the engine shaft, and
when the normal speed is exceeded the governor acts upon the said valve, opening
it more or less, so that the pressure within the vessel or cylinder of the engine does
not rise so high as it otherwise would, and the work performed upon the piston is
lessened, the speed may be thus kept approximately the same.
The construction of the governor is preferably as follows:-A horizontal pin or
spindle is attached to or in proximity to the side of the cylinder or chamber, and
upon or around this a hollow stalk or tube is caused to revolve by means of a
pulley formed with it or attached to it, which pulley is driven by a cord or strap
or its equivalent from the engine shaft. A ring or suitable projections is or are
attached to the said hollow stalk, or tube, or pulley, and to these projections or ring
is attached a spring consisting of a inetallic ribband or thin narrow plate which
passes near to the end of the aforesaid pin or axis at right angles to the axis of the
governor for the main part of its length, but a portion at each end is turned to
come parallel or nearly so with the axis of the governor. These ends are each
attached to the aforesaid ring or projections by means of a screw passing through
each end into the projections or ring. The tension of the spring can be adjusted
by these screws. Weights or balls are attached to the spring and extend one on
each side of the hollow stalk or tube of the governor.
The horizontal pin or spindle on which the hollow stalk or tube of the governor
revolves is tubular, and a rod is free to move longitudinally within it. One end of
the rod is at times born upon by the aforesaid spring, which causes the other end
of the said rod to act upon a valve, which valve is of disc or mushroom form,
opening inward towards the chamber or cylinder of the engine. Flats or grooves
are formed longitudinally on the said rod for the escape of air when the valve is
opened. The action of the governor is as follows:-When the engine exceeds its.
normal speed the balls or weights fly outward and bend the spring, causing its
central part to bear upon the rod, which is moved longitudinally. This rod presses
upon the valve and opens it more or less, thus allowing the air to escape from the
cylinder or vessel, so that the pressure therein does not become so high as it
otherwise would, and the work performed upon the piston is lessened. The speed
may thus be kept approximately the same.
For the purpose of stopping the engine a boss or bandle is attached to the
governor. When this boss is pressed upon it bears against the governor spring
ind presses it against the rod, or bears against the rod, causing the rod to press
gainst the governor valve and open it. Air escapes from the cylinder or chamber,
hus stopping the action of the engine.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Arnold Edmund Robinson and Horace Robinson in the Great
Seal Patent Office on the 17th May 1882.
ARNOLD EDMUND ROBINSON and HORACE ROBINSON, both of Manchester, in the
County of Lancaster. IMPROVEMENTS IN HOT-AIR ENGINES."
#f
Our Invention relates to that class of air engines in which the air is alternately
heated and cooled, and the consequent expansion and contraction and variation of
pressure is utilized to produce motive power.
We construct our engine with a vessel or cylinder open at one end and formed
of suitable metal, such as iron. The part nearer the open end is cooled preferably
by means of a water jacket or tank surrounding it, whilst the part nearer the
closed end is made of a larger internal diameter, and is lined internally with fire-
clay, plumbago, or other material being a good non-conductor of heat. The
internal diameter of the said lining is equal to or slightly larger than the internal
diameter of the cooled part of the cylinder, thus forming a continuation of it. The
lined portion of the cylinder or vessel is closed by an end or heater, preferably of
an egg ended form, or of a partly hollow cylindrical form with an egg end which
extends into the lined part of the cylinder, but leaving a space between the heater
and the said lining. This space constitutes part of the heating chamber. The
beater is formed separately, and is bolted to the chamber or cylinder with a ring
of asbestos or other good non-conductor of heat interposed. The aforesaid enlarged
lined portion of the chamber or cylinder may be formed separately, and attached
to the cooled portion of the cylinder. The object of the aforesaid lining of non-
conductor is to more effectually confine the heat within the heating chamber, and
so that heat shall not readily be transferred to the metal cylinder. The position
of the non-conductor also better separates the heater from the cooled end of
cylinder.
The heater is heated by means of a flame or fire within it in the manner
described hereafter, and the heat is transmitted through it to the air within the
lined portion of the cylinder or chamber.
The heater being of the form already described the pressure within the cylinder
subjects the material of the heater to compression; the heater may with safety be
made thinner than if it were subject to strains of tension, thus heat is easily con-
ducted into the heating chamber. Another advantage of this form of heater is
that it can be carried into the heating chamber within the internal diameter of the
aforesaid lining of non-conductor.
The working piston operates within the aforesaid cooled end of cylinder or
vessel, and a displacing piston combined with a moving regenerator also works
partially within the cool end of said cylinder and partially within the before
mentioned lined portion of the cylinder or chamber, in the manner described here-
after. The working piston is constructed of metal, and is made preferably of
considerable length. On the external diameter may be formed a groove, within
which is placed sponge, or cotton wick, or other suitable material for taking up and
distributing the oil on the sides of the cylinder. At the inner end of the piston a
junk ring is fitted for the purpose of adjusting the main cup leather (turned
inward), which leather works against the sides of the cylinder. A second junk
ring of smaller diameter is fitted to the piston to adjust a small cup leather in the
working piston through which works the displacer rod, or a gland may be sub-
stituted. Within the hollow portion of the working piston are formed two bosses
projecting inward. The piston is connected to the crank shaft by means of a

page_text: connecting rod, the end of which connected to the piston is formed as a ring with
two bosses thereon, which bosses fit between the aforesaid two bosses in the piston.
The said connecting rod is continued from one side of the ring. A pin on each
side is fitted through each of the said bosses on the piston into each of the bosses
on the ring of the connecting rod, so that the connecting rod is free to oscillate.
The other end of the connecting rod is connected to one crank of a two throw
crank shaft. The mode of attaching the working piston connecting rod to the
working piston by means of the ring in the connecting rod and bosses on the
piston is for the purpose of relieving the working piston from undue side strain,
and also to allow the displacer rod and displacer connecting rod to be connected to
the crank shaft conveniently.
The suid crank shaft is made preferably with two cranks set at an angle
of ninety degrees, and as it is desirable to have the crank pins as close to one
another as possible they are connected together by a single sheaf or link.
The displacer rod, which is brought through the small cup leather or gland in
the working piston, is connected to the other crank pin by means of the displacer
connecting rod. The displacer rod is formed with an enlargement or boss upon it
outside or beyond the cup leather, and the rod is carried up through a guide.
A pin is fixed tightly to the small end of the displacer connecting rod, and is free
to work in the boss in the displacer rod. The displacer rod and the small end of
displacer connecting rod can work through the ring end of the working piston
connecting rod, the object of this arrangement of connecting gear is to get a
compact and as direct a connection as possible without imposing undue side
strain.
The combined displacer and regenerator is constructed preferably in the following
manner: A metal cup or piston is made to form the end of the said displacer
furthest away from the heater, the displacer rod is attached thereto. This cap or
piston works within the working cylinder. The outer part of the said cap or
piston is of smaller diameter than the cylinder, and has holes formed through its
sides in such a manner that the air passing out through them from the regenerator
shall be projected against the cool sides of the cylinder.
The said cap or piston is enlarged near its inner end to fit the working cylinder,
and a groove may be turned upon it within which is placed sponge, or wick, or
suitable material to take up and distribute the oil on the sides of the cylinder.
A cylinder, preferably of thin sheet metal, is attached to the aforesaid cap, and is
of such a diameter that it works near to the nonconducting lining of the heating
chamber aforesaid, but leaves a space between the aforesaid lining and the sides of
the said cylinder of thin metal. This cylinder of thin metal is carried to such a
length that when the said combined displacer and regenerator is at the extremity
of its inward stroke, the thin sheet metal shall be interposed between the non-
conducting lining of the heated chamber or cylinder, and the heater leaving an
annular shaped passage on either side of the said thin metal. A cap of cast iron
or other suitable material is attached within the said thin metal cylinder in such a
position that when the displacer is at the end of its inward stroke the said cup
shall nearly touch the egg ended part of the heater. Holes are formed in the thin
metal cylinder of the displacer near to the part where the said cap is attached ;
these holes are for the purpose of allowing the air to pass from the regenerator to
the outside of the said thin metal cylinder. The aforesaid cap is formed so that it
follows the lines or form of the egg end of the heater. Webs are cast on the cap
which support an annular or hollow shaped piece of material, being a good non-
conductor of heat within the said thin metal cylinder, this non-conducting
material extends to or nearly to the outer cap or piston already de-cribed. Within
the inner diameter of the aid non-conductor is placed the regenerator of wire
ga ize or other suitable material presenting a large surface.
At the end of the said non-conductor furthest away from the heater is placed a
ring, and at the same end of the regenerator is placed another ring. These rings
are just within the outer cap or piston of the displacer, and several screws are
'

page_text: placed in the said outer cap bearing on each of the said rings for the purpose of
adjusting the said non-conductor and regenerator, the aforesaid non-conductor
bearing against the said wings or projections of the inner cap with a metal ring
interposed, and the regenerator bearing against the inner cap.
The heating apparatus is constructed preferably in the following manner :-
Round the chimney which carries away the products of combustion of the flaine or
fire is placed a tube or casing of larger diameter or size than the chimney. This
space or passage leads to a chamber or fire box beneath the heater, which chamber
may be lined with a material which is a good non-conductor of heat, such as fire-
clay or cement. The top of the said chamber or fire-box consists of a diaphragm
formed with a tubular extension or up-take upon or attached to it. This tubo or
up-take extends toward the apex of the heater, and being of smaller diameter or
size than the heater a space is left between it and the heater. This space leads to
an annular space opening into the chimney.
When gas is used to heat the apparatus we prefer to use a Bunsen burner within
the closed chamber or fire-box. In the side of the chamber is formed an opening
through which the burner can be withdrawn from the chamber for lighting and
inspection, and replaced. A cover or lid for the opening is formed upon or attached
to the pipe or burner. This lid or cover is larger than the hole or opening in the
chamber. When the burner is in its proper position for use the lid or cover at its lower
side drops in between a stop and the lip of the opening, and the weight of the burner
within the chamber causes the upper part of lid to bear against the lip or opening,
thus closing it.
We do not confine ourselves to gas for heating the apparatus, as liquid or
solid fuel inay be used. When liquid fuel is used, such as petroleum or other
hydrocarbon, the flame of the lamp is used in the chamber or fire-box in place of
the Bunsen burner.
When coal or other solid fuel is used the chamber or fire box is made deeper, and
fire bars are provided within it. The heated air from the space around the chimney
is in this case brought into that part of the chamber below the fire-bars, which
part of the chamber acts as an ash-box. Or air may be brought in direct from the
atmosphere into this part of the chamber without being drawn down the space
around the chimney.
.
•
The action of the engine is as follows:-The heater is heated by means of the
gas flame or fire in the chamber or fire box. The flame being supplied with air
heated by being drawn through the space formed around the chimney, as already
described, the flame or heated products of combustion pass through the tube or
uptake before mentioned and come into contact with the henter and are carried or
drawn down the sides of the heater to the annular space leading to the chimney,
up which they escape.
The air within the heated chamber is heated and the expansion drives the
working piston outward. This actuates the crank shaft, and rather before the
working piston has reached the outer extremity of its stroke the crank shaft causes
the combined displacer and regenerator to commence its travel from the cool portion
of the cylinder to the heated chamber. The air from the heated end or chamber
passes between the sides of the henter and the inner sides of the lower portion of
the thin metal cylinder, forming part of the displacer then passes up part way along
between the outer side of said thin metal cylinder and the inner side of the non-
conductor of the heated chamber, then through the holes or openings through the
thin metal cylinder near to the inner cap of the displacer to the regenerator of
wire gauze or other suitable material contained within the displacer.
The air then passes through the said regenerator, giving up a portion of its heat
to the regenerator, and passes out considerably cooled through the holes or openings
in the outer cap of the displacer. The air rushes through the said holes against the
cooled sides of the working cylinder and is further cooled. The consequent
contraction reduces the pressure in the cylinder and allows the working piston to
descend, continuing the motion of the crank shaft, and rather before the working

page_text: piston has reached the extremity of its inward stroke causes the displacer to commence
its outward stroke. This causes the cool air to rush through the holes in the
outer cap of the combined displacer and regenerator into and, through the
regenerator. Part of the heat previously left in the regenerator is now taken up
by the air in its passage, and the air which is thus partially heated passes over
the inner cap and is further heated, then passes out through the holes or openings
in the thin metal cylinder of the displacer and flows between the outer sides of the
thin metal cylinder and the non-conductor of the heated chamber. The air then
passes between the inner sides of the thin metal cylindrical portion of the displacer
and the heater and is thus heated. the consequent expansion of the air forcing the
working piston outward. Motive power is thus obtained.
The crank actuating the displacer is set so as to move the displacer in advance
of the working piston. In place of the double crank with one intermediate sheaf
or link and connection as described we may connect the working piston by an
ordinary connecting rod to one crank or disc. A pin attached to another disc or
crank or to the fly wheel actuates the combined displacer and regenerator through
the following connections. A rocking arm or lever is provided which oscillates or
works within the aforesaid chamber or cylinder and a recess formed in the side of
the said chamber or cylinder. The combined displacer and regenerator is suitably
connected to the end of this arm or lever, and the other end of said arm or lever
is attached to a rocking shaft, which rocking shaft is carried out through a cup
leather or suitable packing. Another arm or lever is attached outside to the said
rocking shaft, and this arm or lever is connected by a rod to the aforesaid crank or
disc pin or pin in the fly wheel.
In some cases, ns, for instance, where the engine is required for pumping, we may
invert the engine, the heated end being then upperinost, and we may connect the
piston to the working crank by means of a rod extending outward, which rod at
or about its extremity furthest away from the piston is suitably guided and a
connecting rod is jointed to it. This connecting rod extends back to the crank
pin. An oil cup of an annular trough or channel form is attached to the open end
of cylinder when this end is downward, and a lip or ring may be formed upon the
piston which dips into oil within this oil cup and carries oil up the sides of the
cylinder to lubricate it. Sponge or wick or other suitable material may be laid in
this oil cup and the oil will be prevented from splashing.
Where the engine is required to work a pump the pump may act as a guide
for the piston rod, which red extends downward and is attached directly to the pump.
The piston in this case works directly on to the pump, and the weight of the
piston and its connections will, to a certain extent, balunce the column of water or
other fluid.
In engines with the open end of chamber or cylinder downward and the heater
uppermost we prefer to use gaseous or liquid fuel, and the heating apparatus may
be arranged substantially in the same manner as alrendy described, but will be
inverted and the burner may be inserted from the top instead of from the side.
Or a ring or annular buiner may be used, and in this case the products of com-
bustion and heat of the flaine are drawn over and into the heater and up through
a tube which projects down towards the end of the heater and conducts the
products of combustion to the chimney.
A cover of fire-clay or other refractory .non-conducting material is provided to
prevent or lessen the radiation of heat.
The speed of the engine may be governed in the following manner:-A small
valve at certain times opens communication between the enclosed air within the
chamber or cylinder and the outside air. A centrifugal governor, which may be
substantially of the form described hereafter, is driven from the engine shaft, and
when the normal speed is exceeded the governor acts upon the said valve, opening
it more or less, so that the pressure within the vessel or cylinder of the engine does
not rise so high as it otherwise would and the work performed upon the piston is
lessened; the speed may be thus kept approximately the same. The construction

page_text: of the governor is preferably as follows:-A horizontal pin or spindle is attached
to or in proximity to the side of the cylinder or chamber, and upon or around this
a hollow stalk or tube is caused to revolve by means of a pulley formed with it or
attached to it, which pulley is driven by a cord or strap or its equivalent from the
engine shaft. A ring or suitable projections is or are attached to the said hollow
stalk or tube or pulley, and to these projections or ring is attached a spring con-
sisting of a metallic ribbon or thin narrow plate, which passes near to the end of
the aforesaid pin or axis at right anglos to the axis of the governor for the main
part of its length, but a portion at each end is turned to come parallel or nearly
so with the axis of the governor. These ends are each attached to the aforesaid
ring or projections by means of a screw passing through each end into the pro-
jections or ring; the tension of the spring can be adjusted by these screws.
Weights or balls are attached to the spring, and extend one on each side of the
hollow stalk or tube of the governor. The horizontal pin or spindle on which the
hollow stalk or tube of the governor revolves is tubular, and a rod is free to move
longitudinally within it. One end of the rod is at times borne upon by the afore-
said spring, which causes the other end of the said rod to act upon a valve, which
valve is of disc or mushroom form opening inward towards the chamber or cylinder
of the engine. Flats or grooves are formned longitudinally on the said rod for the
escape of air when the valve is opened. The action of the governor is as follows:-
When the engine exceeds its normal speed the balls or weights fly outward and
bend the spring, causing its central part to bear upon the rod which is moved
longitudinally. This rod presses upon the valve and opens it more or less, thus
allowing the air to escape from the cylinder or vessel, so that the pressure therein
does not become so high as it otherwise would, and the work performed npon the
piston is lessened. The speed may thus be kept approximately the saine.
For the purpose of stopping the engine a boss or handle is attached to the
governor. When this boss is pressed upon it bears against the governor spring
and presses it against the rod, or bears against the rod, causing the rod to press
against the governor valve and open it. Air escapes from the cylinder or chamber,
thus stopping the action of the engine.
And in order that our Invention may be fully understood and readily carried
into effect, we will describe the accompanying Sheet of Drawings, reference being
had to the figures and letters marked thereon.
Fig. 1 is a vertical section of a hot air engine taken in line with the crank
shaft; Fig. 2 is a vertical section on x, x, Fig. 1.
A is the vessel or cylinder, open at one end surrounded at its cooled or working
end A' by a water jacket or tank A, and at its heated end having a lining A³ of
fire-clay, cement, plumbago, asbestos, or other material being a good non-conductor
of heat. The lined portion of the cylinder may be formed separately and attached
to the cooled portion of the cylinder; B is the henter of an egg ended form or
partly of a hollow cylindrical form with an egg end. This beater extends into the
lining A³ of the cylinder or vessel but leaves a space a between the heater B and
lining A. The space a constitutes part of the heating chamber. The object of
the lining A³ is to more effectually confine the heat within the heating chamber a,
and so that heat shall not readily be transferred to the metal cylinder or vessel.
The position of the non-conductor lining A³ also better separates the henter B from
the cooled part of cylinder or vessel.
The heater B is preferably formed separately, and is attached or bolted to the
cylinder or vessel A with a ring B', of asbestos or other good non-conductor of heat
interposed.
The heater B, being of the form described, the pressure within the cylinder
subjects the material or part of the material of the heater to compression, and the
heater may with safety be made thinner than if it were subject to strains of
tension, thus heat is more readily conducted into the heating chamber.
Another advantage of this form of heater is that it can be carried into the
heating chamber within the lining A³; C is the working piston which works

page_text: within the cooled end of cylinder A'. A groove c may be formed on the piston,
within which may be placed sponge or cotton wick or other suitable material for
taking up and distributing the oil on the sides of the cylinder; C' is a cup leather
turned inward; C is a smaller cup leather; C is a junk ring for adjusting the cup
leather C; C is a junk ring for adjusting cup leather C'; C, C, are two bosses
formed within the working piston and project inward.
The crank shaft E is made with two cranks E, E, set at about an angle of ninety
degrees, and as it is desirable to have the crank pins E, E, as close to one another
as possible, they are connected together by a single sheaf or link Es.
F is the combined displacer and regenerator, and is constructed in the following
manner-F is a metal cap or piston forming the end of displacer and regenerator F.
This cap or piston F¹ works within the cylinder A'. The outer portion of cap
F¹
is of smaller diameter than the cylinder A, and has holes or openings fff
formed through its sides. The enlarged end of cap F1 fits the cylinder A. Fis
a hollow cylinder or hood, preferably of sheet metal, which is attached to the
cap F', and is of such a diameter that it works within the lining A³, but leaves
a space between itself and the lining A³. This cylinder or hood F is of such a
length that when the combined displacer and regenerator F is at the extremity of
its inward stroke, part of the thin inetal F shall be interposed between the lining A³
of the heater B, leaving an annular shaped passage on either side of F. F³ is a
cap, preferably of metal, attached within F, in such a position that when the
combined displacer and regenerator is at the end of its stroke, as shown in Fig. 1,
the said cap shall be close to the egg ended part of the heater B. Holes f³ffs,
are formed in the thin metal cylinder F near to the part where the cap F³ is
attached. These holes f³, f, f, are for the purpose of allowing the air to pass
from the regenerator to the outside of the hood or cylinder F. The cap F³ is
formed so that it follows the lines or form of the egg end of the heater B. Webs
may be formed on the cap; these webs support an annular or hollow shaped picco
of material, such as asbestos or fireclay, being a good non-conductor of heat;.
this material f³ extends towards the outer cap F. F' is the regenerator of wire
gauze or other suitable material, presenting large surface. At the end of the
non-conductor f5 furthest away from the heater may be placed a ring ƒ³, and at
the same end of the generator F is placed another ring f. These rings are
within the cap Ft, and several screws may be placed in the cap F' bearing on each
of the said rings ",", for the purpose of adjusting the aforesaid non-conductor fb.
D is the connecting rod for connecting the piston C to the crank shaft E. The
end of the connecting rod D which is attached to the piston is formed as a ring D'
(shown more clearly in Fig. 1) with two bosses d, d, thereon; these bosses fit
between the bosses Co, C. A pin on each side is fitted through each of the said
bosses C, Co, into each of the said bosses d, d, so that the connecting rod D is free
to oscillate. The other end of the connecting rod D is connected to a crank E¹ of
the crank shaft E.
F³ is the displacer rod brought through the cup leather Cs or gland in the
working piston C. This rod F³ is connected to the crank pin E2 by means of a
connecting rod F, and works through a guide F. The displacer rod F³ is formed
with an enlargement or boss f upon it outside or beyond the cup leather C².
A pin is fixed tightly to the small end of the connecting rod F, and is free to
work in the boss on the rod F³. The rod F³ and sinall end of displacer con-
necting rod F can work through the ring end D' of the piston connecting rod D.
The object of this arrangement of connecting gear is to get a direct connection
between the crank shaft and the reciprocating parts. R is a governor for regu-
lating the speed of the engine in the manner described hereafter. G is a chimney
to carry away the products of combustion of the flame or fire; G' is a casing.
around the chimney G, but leaving a space g between the chimney G and casing G¹.
This space or passage g leads to a chamber or fire box G. This chamber inay have
a lining G² of a material which is a good non-conductor of heat; G³ is a diaphragm
formed with a tubular extension or up-take G upon or attached to it. This

page_text: uptake G* extends towards the heater B, and being of smaller diameter or size than
the heater B a space g³ is left between G' and B. This space g³ leads to an annular
space opening into the chimney G; H is a Bunsen gas burner within the
chamber G In the side of the chamber G is formed an opening h, through which
the burner can be withdrawn from the chamber for lighting and inspection and
can be replaced. A cover or lid for the opening his formed upon or attached
to the pipe or burner H. The lid h¹ is larger than the hole or opening h. When
the burner H is in its proper position for use, as shown, the lid h' at its lower side
drops in between a stop hand the lip of the opening h, and the weight of the
burner H within the chamber causes the uppermost part of the lid h' to bear
against the lip of the opening, thus closing it.
When liquid fuel such as petroleum or other hydrocarbon is used instead of gas
the flame of the lamp is used in the chamber G in place of the Bunsen burner H.
The action of the engine, as shown at Figs. 1 and 2, is as follows:-The heater B
is heated by the flame of the Bunsen burner H or fire, the flame being supplied
with air heated by being drawn through the space g formed around the chimney G,
as already described, the flame or heated products of combustion pass through the
tube or uptake G and come in contact with the heater B, and are carried along
the sides of the heater (as shown by the arrows 1, 1, Fig. 2) to the annular space g
leading to the chimney G up which they escape.
The air or part of the air within the cylinder or vessel A is caused to flow from
the cooled to the heated part and from the heated to the cooled pirt alternately
by the action of the combined lisplacer and regenerator F on the principle of the
Sterling" hot air engine. The regenerator is actuated by the crank E³, which
"
is in advance of the crank E¹.
When the combined displacer and regenerator F is moved from the beated to the
cooled part, the air or part of the air passes in the direction of the arrows 1, 1,
Fig. 2, from the cooled part through the holes f. f', into and through the regene-
rator F, taking up some of the heat left in the regenerator by the previous instroke.
The air then passes through the holes f³, f³, then between the lining A³ and hood F³,
and round between the hood F and the heater B. The air is thus heated, and the
consequent expansion drives the piston C outward.
When the combined displacer and regenerator is moved from the cooled to the
heated part of the cylinder or vessel A, the air or part of the air passes in the
opposite direction to that shown by the arrows 1, 1, Fig. 2, and the air in passing
through the regenerator F gives up a portion of its heat to the regenerator, and
passes out into the cooled part of cylinder or vessel and is further cooled, and the
consequent contraction allows the piston C to perform its inward stroke,
Another arrangement of gear is shown at Figs. 3 and 4, of which Fig. 3 is a
vertical section taken at right angles to the crank shaft, and Fig. 4 is an elevation,
partly in section. In this arrangement the heated end of the cylinder or vessel
is shown uppermost. K is the crank shaft; K¹ is a disc or crank. The working
piston C is connected to the crank pin by a piston rod L extending outward, and
a connecting rod L' extending back to the crank pin. M is a pump for raising
water or other. Huid, and is attached to the piston rod L, forming a guide. The
working piston C thus works directly on to the pump M, and the weight of the
piston and its connections will to a certain extent help to balance the column of
water or other fluid raised by the pump. The ram m of the pump M is stationary,
and upon this ram works a hollow casing M, and to which the piston rod L is
attached. A way or port m³ is brought through the ram m.
The pump is
provided with a suction and delivery valve. The connecting rod L' is free to
Oscillate on a pin Z on the casing M, or on a crosshead. K is a second crank pin,
and may be attached to the fly wheel K³, or to a disc or crank. This crank pin K
has the lead of the crank pin K by about ninety degrees. N is a rocking lever
connected to the crank pin K by a connecting rod K. The rocking arm or lever N
is attached to a rocking shaft N₁, which passes through a cup leather N' into a
recoss N³ formed on the cylinder or vessel A. N³ is a rocking arun or lever

page_text: attached to the rocking shaft N' within the recess N³. The end n² of the lever N³
is connected to the combined displacer and regenerator F. O is an oil cup of an
annular trough or channel form. This cup is attached to the open end of
cylinder A, and a lip or ring o¹ may be formed upon the piston which dips into
oil within the cup O, and carries oil up the sides of the cylinder A to lubricate it.
Sponge or wick or other suitable material may be laid in the oil cup to prevent the
oil from splashing.
In this form of engine shown, as on Figs. 3 and 4, we prefer to use a ring or
annular burner P, and the products of combustion and the heat of the dame are
drawn over and into the heater B and up through the chimney or tube G. Q is a
cover of fire clay or other suitable refractory material, being a gond non-conductor
of heat provided to retard the radiation of heat. G' is a casing forming an annular
space g around the chimney G, and forming a hood or cover over the heating
apparatus. The air to supply the flame is drawn down this annular space g, and
becomes heated before reaching the flame, as described in reference to Fig. 2. The
chimney Ginny be constructed so that it may be drawn up to about the place
shown in dotted lines. This is for the purpose of preventing a down draught
when the burner is first lighted. In the arrangement of the engine shown at
Figs. 3 and 4 the action of the air within the cylinder or vessel is similar to that
in Figs. 1 and 2, but we prefer in this arrangeinent when used for pumping to
have the heated end uppermost, as shown in the Drawings, Fig. 3 and 4.
R, Fig. 1, is a governor for regulating the speed of the engine; Fig. 5 is &
sectional view, and Fig. 6 an end view on a larger scale. is a pin or spindle
attached to the side of the cylinder A, and upon the pin ra hollow stalk or tube 7
is caused to revolve by means of a pulley formed with it or attached to it. This
pulley is driven by a cord or strap or its equivalent from the engine shaft or
pulley R, or suitable projections is or are attached to or formed with the hollow
stalk r, and to 7 is attached a spring, which pas.es near to the end of the pin r.
The ends 7, 77, are turned parallel to the axis of the governor. These en is 77, 77,
are each attached to the ring 7 by means of screws 7, 78, passing through each end
into the ring. The tension of the spring can be adjusted by these screws 8.
Weights or balls 70, 70, are attached to the spring ro. The pin ris tubular, and a
rod 8 is free to move longitudinally within it. One end of the rod 8 is at times
borne upon by the spring. This causes the other end of the rod a to act upon
the valve s'; this valve is of a disc or mushroom form, opening inward towards the
cylinder A. Flats or grooves & are formed longitudinally on the rod & for the
escape of air when the valve s¹ is opened.
The action of the governor is as follows:-When the engine exceeds its normal
speed the balls or weights 70, 79, fly outward and bend the spring, causing its
central part to bear upon the rod 8, which is moved longitudinally in the direction
of the arrow 3. This rod 8 presses upon the valve & and opens it more or less,
thus allowing the air to escape from the cylinder, so that the pressure therein
does not become so high as it otherwise would, and the work performed upon the
piston c is lessened. The speed inay thus be kept approximately the same.
For the purpose of stopping the engine a boss or handle is attached to the
governor. When the boss is pressed upon it bears against the spring and presses
it against the rod 8, or bears against the rod s, causing the rod to press against the
valve & and opens it. Air escapes from the cylinder A, thus stopping the action of
the engine.
Having stated the nature of our Invention and described the manner of performing
the same,
We declare that we claim,-
1. In a hot air engine the combination of a double crank shaft E having one
sheaf or link between the two crank pins, with the connecting rod D from the
crank pin connected to the piston C as shown, so as to allow without causing
undue side strain the rod F to work through a cup leather Cor gland in the
piston, and the other crank pin being connected to the rod F³ by connecting

page_text: rod F, as hereinbefore described and illustrated in Figs. 1, 1ª, and 2 of the
accompanying Drawings.
2. In a hot air engine a rocking arm or lever actuating a displacer or regenerator
working within the cylinder or chamber. The said rocking arm or lever being
attached to a rocking shaft passing through a cup leather or gland into the open
air, the said rocking shaft having on the part outside the cup leather N or
gland another rocking arm or lever connected to a crank on the main crank shaft
of the engine, as hereinbefore described and illustrated in Figs. 3 and 4 of the
accompanying Drawings.
3. In a hot air engine a casing or hood or cylinder of thin metal F³ with
openings ff. The said easing containing a regenerator F and cap F³, the
hood F being arranged so that air shall pass through the holes, and
ff, fs, and over the heater B, as herein before described and illustrated in the
accompanying Drawings.
4. In a hot air engine the lining A³ within the cylinder or vessel for more
effectually confining the heat, the said lining As surrounding the heater B, a space
being leit between the heater B and lining As, in which space the hood F works,
as herein before described and illustrated in the accompanying Drawings.
5. In a hot air engine the combination of the heater B with the chamber G³,
having uptake G*, chimney G, and casing G¹, forming a space g, so that the heat of
the products of combustion passing up the chimney may heat the air for supporting
the flame for heating the heater, in the manner and for the purpose described and
illustrated in Figs. 1 and 2 of the accompanying Drawings.
6. In a hot air engine, as described, the combination of the henter B with the
heating arrangement, consisting of a ring burner P and chimney or tube G, as and
for the purpose herein before described and illustrated in Figs. 3 and 4 of the
accompanying Drawings.
7. In a hot air engine used for pumping the combination of the gear for working
the displacer or regenerator, with the arrangement for connecting the working
piston directly to the pump, as hereinbefore described and illustrated in Figs. 3
and 4 of the accompanying Drawings.
8. A centrifugal speed governor having the weights or balls attached to a spring,
which acts upon the spindle in the manner hereinbefore described and illustrated
in the accompanying Drawings.
In witness whereof, we, the said Arnold Edmund Robinson and Horace
Robinson have hereunto set our hands and seals this Sixteenth day of May,
One thousand eight hundred and eighty two.