IMPROVEMENTS IN ENGINES WORKED BY THE COMBUSTION OF INFLAMMABLE ARRIFORM FLUIDS, AND IN APPARATUS FOR PRODUCING SUCH FLUIDS
Year: 1867

page_text: LETTERS PATENT to Matthew Piers Watt Boulton, of Tew Park,
Oxfordshire, Esquire, for the Invention of "IMPROVEMENTS IN ENGINES
WORKED BY THE COMBUSTION OF INFLAMMABLE ARRIFORM FLUIDS, AND IN
APPARATUS FOR PRODUCING SUCH FLUIDS,"
Sealed the 7th January 1868, and dated the 8th July 1867.
PROVISIONAL SPECIFICATION left by the said Matthew Piers Watt
Boulton at the Office of the Commissioners of Patents, with his Petition,
on the 8th July 1867.
I, MATTHEW PIERS WATT BOULTON, of Tew Park, Oxfordshire, Esquire,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
ENGINES WORKED BY THE COMBUSTION OF INFLAMMABLE AERIFORM FLUIDS, AND IN
APPARATUS FOR PRODUCING SUCH FLUIDS," to be as follows:-
One part of my Invention relates to improvements in apparatus described
in the Specification of my former Patent, No. 738, 10th March, 1866.
In this apparatus the ignition of an explosive aeriform mixture is used to
propel a piston, and thereby compress air or fluid in a chamber, which com-
pressed fluid is employed to produce motive power, and the heated products
of combustion are applied to a boiler for the generation of steam, which may
be used in the same engine as the compressed fluid; or the products of com-
bustion may be employed to give out heat for other purposes.
The following is one arrangement of the apparatus :-I place the cylinder
with its axis vertical and fit it with a piston to move freely in it. The upper

page_text: end of the cylinder has passages covered by valves opening upwards into the
chamber which is intended to receive the compressed air or fluid; there is
also close to the upper end of the cylinder, but placed for convenience at the
side a passage fitted with a valve opening inwards, which serves as the inlet
for the air or fluid to be compressed; at the lower end of the cylinder is a
spring which may either be of elastic material such as steel, or may consist of
a plunger fitting an air cylinder. There are also at the lower end of the
cylinder passages fitted with valves opening inwards for the admission of the
inflammable mixture into the cylinder and an exit passage fitted with a cock
or slide valve for the discharge of the products of combustion. This exit
valve is so arranged that it is closed when the piston reaches the bottom of
the cylinder, and is opened when the piston reaches the top, or it may be a
valve mounted on a spring adjusted so that it remains open when subjected
to the moderate pressure caused by the descent of the piston in the cylinder
but is closed by the greater pressure resulting from the ignition of the
infammable matter.
The apparatus acts in the following manner :-The piston having been
propelled to the top of the cylinder, and there left free, descends by its own
weight and expels the contents of the cylinder beneath it by the exit valve
at the bottom. The valves covering the passages to the chamber containing
the compressed fluid close while the inlet valve at the top of the cylinder
opens to admit the fluid to be compressed into the cylinder above the piston.
The piston in approaching the bottom of the cylinder compresses the spring,
and having reached the bottom is caused by the spring's recoil to ascend a
certain distance, and while it so rises, the exit valve being closed, the valves
for supplying the inflammable mixture open and admit the mixture into the
space beneath the piston, where it is ignited. The explosion propels the
piston to the top of the cylinder, and the fluid contained in the cylinder above
the piston is thus forced through the upper valves into the chamber. The
piston having thus been raised to the top of the cylinder descends again, and
the action is repeated as above described. I sometimes fit the piston with a
plunger working through a stuffing box into the chamber containing the com-
pressed fluid, so that the pressure acting on the end of the plunger causes the
return of the piston independently of gravity; in this case the cylinder may
be placed in any position.
Another method of constructing the apparatus is the following:-Two
pistons are employed, the one being propelled by the explosion, and serving
to compress the fluid into the chamber, while the other is worked by a
rod conected with the moving parts of the machinery, and has for its office

page_text: to expel the products of combustion and draw in the charge of inflammable
mixture. I will call the former piston the driving piston and the latter the
charging piston. The charging piston works within a cylindrical ring fitting
the cylinder between stops so arranged that the charging piston can move a
certain distance within the ring without moving the ring, but when moved
beyond this distance it carries the ring with it along the cylinder. The driving
piston works loosely in the cylinder in front of the ring, which acts as a stop
to it and prevents it from ever reaching the bottom of the cylinder.
The mode of action is as follows :-The charging piston with its ring is
drawn back to the bottom of the cylinder with the driving piston in front of
the ring. The space between the two pistons contains the inflammable mix-
ture, and the space between the driving piston and the valve of the receiver
contains the air or fluid which it is desired to compress within the receiver.
The inflammable mixture is ignited, and the force of the consequentexpansion
propels the driving piston, which compresses the fluid in front of it, and drives
it through the valves into the receiver; the driving piston having made its
stroke and the propulsive force being spent the valve of the receiver closes,
an eduction valve is opened, and the charging piston makes a stroke forward
carrying the ring with it and driving out the products of combustion which
issue into a passage or passages in which their heat is utilized; fluid enters
the cylinder behind the charging piston. The charging piston having made
its forward stroke and expelled the products of combustion the eduction
valve through which they issued is closed and a valve opened for the admission
of air or fluid; the charging piston is drawn back and the driving piston
follows it, the air or fluid entering between the driving piston and the valve of
the receiver; the fluid on the other side of the charging piston is driven out
through an e luction valve. When the stroke has been so far made that the
motion of the ring is stopped against the bottom of the cylinder the driving
piston is also stopped by the ring, and the admission of the fluid between the
driving piston and the valve of the receiver is stopped. The charging piston
continues to move within the ring and to drive out the fluid behind it while
the inflammable mixture enters through valves opened for the purpose into the
space between the charging piston and the driving piston; the charging piston
having completed its stroke the operation is repeated as already described.
The fluid driven and compressed by the driving piston may be air, or it may
be steam, the steam discharged from the engine being thus used; also
products of combustion discharged after having generated steam may be
similarly used.
In engines constructed as above described the inflammable gas used as an

page_text: ingredient of the inflammable mixture may be procured from the imperfect
combustion of carbonaceous fuel, such as coke and coal. When coal is used
the following method may be employed:-The coal is supplied to a circular
trough, plate, or piece revolving in a chamber; by this revolution the coal is
continually brought to a certain portion of the chamber where it is burnt and
consumed,a limited supply of air being admitted for the combustion or forced
in under pressure. The products of combustion are caused to pass over the
surface of the coal as this is brought by the revolving plate towards the spot
where the combustion takes place. The carbonic acid uniting with carbon
produces carbonic oxide, while the heat of the gases causes the expulsion of
carburetted hydrogen and volatile constituents of the coal; the resulting
mixture is used as inflammable gas. Other things remaining the same the
coal may be caused to move to the spot where it is consumed by movements
other than rotary, or it may be caused to move by sliding down inclined planes
by the action of its own weight. Coal moistened with petroleum, hydro-
carbons, or inflammable liquids may be treated in a similar manner, and other
sorts of fuel may be similarly treated. In the methods above described
steam may be employed along with the products of combustion. Again,
heated gases produced by the combustion of coal or fuel treated as above
described, may be caused to pass over or through petroleum or inflammable
liquids, or among surfaces over which inflammable liquids flow, or through
which they percolate, and the resulting gases may be employed as an ingredient
in the inflammable mixture used in the engine.
Another method of treating coal, coke, or other solid fuel is as follows:-
The fuel is reduced to a state of powder or dust, and in this state is caused to
pass through the products of combustion or through these mixed with steam
to the part of the chamber in which combustion takes place. The finely
comminuted fuel may fall through the heated gases by its weight, or may be
carried into them by a jet of steam. Gases obtained in the manners above
described may also be employed for general purposes of combustion. Inflam-
mable gas to be used in the engine may also be obtained from petroleum.
For this purpose the following method may be employed:-The petroleum is
caused to flow over a surface or surfaces towards a chamber in which it under-
goes combustion; the air employed for this purpose may be forced in under
pressure. The products of the combustion are caused to pass over or in
contact with the petroleum as it flows towards the chamber in which the com-
bustion takes place; steam may be mixed with the products of combustion thus
employed. The resulting gases are employed as a portion of the inflammable
mixture used in the engine. Gases thus obtained may also be used for com-

page_text: に
bustion for general purposes. Hydrocarbons and other liquids capable of
generating inflammable vapour or gas under the action of heat may be treated
in a similar manner. The surfaces over which the petroleum or liquid is
caused to pass may be disposed in various manners; a number of inclined plates
may be employed over which the liquid flows in a zig-zag course. Again, the
petroleum or liquid may be caused to pass through the products of com-
bustion or through these mixed with steam in a finely divided state, for which
purpose it may be caused to flow through numerous apertures in small streams
or dashed against the sides of the chamber from a jet or jets so as to be con-
verted into fine spray passing in this way to the place or chamber where com-
bustion takes place, and this method may be combined with that previously
described. A jet of steam or air may be used to convey petroleum or other
liquid fuel in a state of spray into a chamber where it is treated in the manner
previously described for the purpose of generating inflammable gas.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Matthew Piers Watt Boulton in the Great Seal Patent
Office on the 8th January 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MATTHEW
PIERS WATT BOULTON, of Tew Park, Oxfordshire, Esquire, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of July, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirty-first year of Her reign,
did for Herself, Her heirs and successors, give and grant unto me, the said
Matthew Piers Watt Boulton, Her special licence that I, the said Matthew
Piers Watt Boulton, my executors, administrators, and assigns, or such
others as I, the said Matthew Piers Watt Boulton, my executors, adminis
trators, 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,
sbould 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 ENGINES WORKED BY THE COMBUSTION OF
INFLAMMABLE AERIFORM FLUIDS, AND IN APPARATUS FOR PRODUCING SUCH FLUIDS,"
upon the condition (amongst others) that 1, the said Matthew Piers Watt
Boulton, 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

page_text: 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 Matthew Piers Watt Boulton, 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, that is to say :—
One part of my Invention relates to improvements in apparatus described
in the Specification of my former Patent, No. 738, 10th March 1866.
In this apparatus the ignition of an explosive aeriform mixture is used to
propel a piston, and thereby compress air or fluid in a chamber, which com-
pressed fluid is employed to produce motive power, and the heated products of
combustion are applied to a boiler for the generation of steam, which may be
used in the same engine as the compressed fluid, or the products of combustion
may be employed to give out heat for other purposes.
The following is one arrangement of theapparatus:-I place the cylinder with
its axis vertical, and fit it with a piston to move freely in it. The upper end
of the cylinder has passages covered by valves opening upwards into the
chamber, which is intended to receive the compressed air or fluid; there is
also close to the upper end of the cylinder, but placed for convenience at the
side, a passage fitted with a valve opening inwards, which serves as the inlet
for the air or fluid to be compressed. At the lower end of the cylinder is a
spring which may either be of elastic material such as steel, or may consist of a
plunger fitting an air cylinder. There are also at the lower end of the cylinder
passages fitted with valves opening inwards for the admission ofthe inflammable
mixture into the cylinder, and an exit passage fitted with a cock or slide valve
for the discharge of the products of combustion. This exit valve is so arranged
that it is closed when the piston reaches the bottom of the cylinder and is
opened when the piston reaches the top, or it may be a valve mounted on a
spring adjusted so that it remains open when subjected to the moderate
pressure caused by the descent of the piston in the cylinder, but is closed
by the greater pressure resulting from the ignition of the inflammable
matter.
The apparatus acts in the following manner :-The piston having been
propelled to the top of the cylinder, and there left free, descends by its own
weight and expels the contents of the cylinder beneath it by the exit valve at
the bottom. The valves covering the passages to the chamber containing the
compressed fluid close, while the inlet valve at the top of the cylinder open
to admit the fluid to be compressed into the cylinder above the piston. The

page_text: piston in approaching the bottom of the cylinder compresses the spring, and
having reached the bottom is caused by the spring's recoil to ascend a certain
distance,andwhile it so rises the exit valve being closed the valves for supplying
the inflammable mixture open and admit the mixture into the space beneath
the piston where it is ignited. The explosion propels the piston to the top of
the cylinder, and the fluid contained in the cylinder above the piston is thus
forced through the upper valves into the chamber. The piston having thus
been raised to the top of the cylinder descends again,and the action is repeated
as above described. I sometimes fit the piston with a plunger working through
a stuffing box into the chamber containing the compressed fluid so that the
pressure acting on the end of the plunger causes the return of the piston
independently of gravity. In this case the cylinder may be placed in any
position.
Another method of constructing the apparatus is the following:-Two
pistons are employed, the one being propelled by the explosion and serving to
compress the fluid into the chamber, while the other is worked by a rod
connected with the moving parts of the machinery, and has for its object to
expel the products of combustion and draw in the charge of inflammable
mixture; I will call the former piston the driving piston, and the latter the
charging piston. The charging piston works within a cylindrical ring fittingthe
cylinder between stops so arranged that the charging piston can moveacertain
distance within the ring without moving thering,but when moved beyond this
distance it carries the ring with it along the cylinder. The driving piston
works loosely in the cylinder in front of the ring, which acts as a stop to it and
prevents it from ever reaching the bottom of the cylinder.
The mode of action is as follows:-The charging piston with its ring is
draw back to the bottom of the cylinder with the driving piston in front of
the ring. The space between the two pistons contains the inflammable
mixture,and the space between the driving piston and the valve of the receiver
contains the air or fluid which it is desired to compress within the receiver.
The inflammable mixture is ignited and the force of the consequent expansion
propels the driving piston, which compresses the fluid in front of it and drives
it through the valves into the receiver; the driving piston having made its
stroke, and the propulsive force being spent, the valve of the receiver closes,
an eduction valve is opened, and the charging piston makes a stroke forward
carrying the ring with it and driving out the products of combustion, which
issue into a passage or passages in which their heat is utilised. Fluid enters
the cylinder behind the charging piston. The charging piston having made
its forward stroke and expelled the products of combustion the eduction valve

page_text: through which they issue is closed,and a valve opened for the admission of air
or fluid, the charging piston is drawn back, and the driving piston follows it,
the air or fluid entering between the driving piston and the valve of the
receiver. The fluid on the other side of the charged piston is driven out
through an eduction valve; when the stroke has been so far made that the
motion of the ring is stopped against the bottom of the cylinder the driving
piston is also stopped by the ring, and the admission of the fluid between the
driving piston and the valve of the receiver is stopped. The charging piston
continues to move within the ring, and to drive out the fluid behind it, while
the inflammable mixture enters throughvalves opened for the purpose into the
space between the charging piston and the driving piston; the charging
piston having completeditsstroketheoperationisrepeatedas already described.
The fluid driven and compressed by the driving piston may be air,or it may be
steam, the steam discharged from the engine being thus used also products of
combustion discharged after having generated steam may be similarly used.
In engines constructed as above described the inflammable gas used as an
ingredient of the inflammable mixture may be procured from the imperfect
combustion of carbonaceous fuel, such as coke and coal. When coal is used
the following method may be employed:-The coal is supplied to a circular
trough, plate, or piece revolving in a chamber; by this revolution the coal is
continually brought to a certain portion of the chamber where it is burnt and
consumed,a limited supply of air being admitted for the combustion or forced
in under pressure. The products of combustion are caused to pass over the
surface of the coal as this is brought by the revolving plate towards the spot
where the combustion takes place. The carbonic acid uniting with carbon
produces carbonic oxide, while the heat of the gases causes the expulsion of
carburetted hydrogen and volatile constituents of the coal; the resulting
mixture is used as inflammable gas. Other things remaining the same the,
coal may be caused to move to the spot where it is consumed by movements
other than rotary; or it may be caused to move by sliding down inclined
planes by the action of its own weight. Coal moistened with petroleum,
hydrocarbons, or inflammable liquids may be treated in a similar manner, and
other sorts of fuel may be similarly treated. In the methods above described
steam may be employed along with the products of combustion. Again heated
gases produced by the combustion of coal or fueltreatedasabovedescribed may
be caused to pass over or through petroleum or inflammable liquids, or among
surfaces over which inflammable liquids flow or through which they percolate,
and the resulting gases may be employed as an ingredient in the inflammable
mixture used in the engine.

page_text: Another method of treating coal, coke, or other solid fuel is as follows:-
The fuel is reduced to a state of powder or dust, and in this state is caused to
pass through the products of combustion, or through these mixed with steam
to the part of the chamber in which combustion takes place. The finely com-
minuted fuel may fall through the heated gases by its weight, or may be
Gases obtained in the manner above
carried into them by a jet of steam.
described may also be employed for general purposes of combustion.
Inflammable gas to be used in the engine may also be obtained from
petroleum. For this purpose the following method may be employed:-The
petroleum is caused to flow over a surface or surfaces towards a chamber in
which it undergoes combustion. The air employed for this purpose may be
forced in under pressure. The products of the combustion are caused to pass
over or in contact with the petroleum as it flows towards the chamberin which
the combustion takes place. Steam may be mixed with the products of com-
bustion thus employed. The resulting gases are employed as a portion of the
inflammable mixture used in the engine; gases thus obtained mayalsobeused
for combustion for general purposes. Hydrocarbons andotherliquids capable
may be
of generating inflammable vapour or gas under the action of heat
treated in a similar manner. The surfaces over which the petroleum or liquid
is caused to pass may be disposed in various manners. A number of inclined
plates may be employed, over which the liquid flows in a zig-zag course.
Again the petroleum or liquid may be caused to pass through the products of
combustion or through these mixed with steam in a finely divided state, for
which purpose it may be caused to flow through numerous apertures in small
streams or dashed against the sides of the chamber from a jet or jets, so as to
be converted into fine spray, passing in this way to the place or chamber
where combustion takes place; and this method may be combined with that
previously described. A jet of steam or air may be used to convey petroleum
or other liquid fuel in a state of spray into a chamber, where it is treated in the
manner previously described for the purpose of generating inflammable gas.
DESCRIPTION OF THE DRAWINGS.
Figure 1 represents a longitudinal section of one form of apparatus whereby
the ignition of an inflammable aeriform substance or mixture is used to propel
a piston and thereby compress air in a chamber, which compressed air is
employed to produce motive power. a is a cylinder placed with its axis
vertical, and having a piston 6 fitted to move freely in it; c is a chamber for
receiving compressed air, which chamber is separated from the cylinder a by
a grating covered by a flexible valve c¹, so that air can pass freely from a to c,

page_text: but cannot return; d is a valve opening upwards in a recess formed in the
upper part of the cylinder a, two valves one of which is represented at e are
fitted side by side in the bottom of the cylinder so as to open upwards; each of
those valves at e has a passage regulated by a stop-cock, the one being made
to communicate with the atmosphere, and the other with a reservoir containing
inflammable gas or vapour. f is a valve with double seatings, so that when it
rises or falls to its full extent it closes the passage in which it is fitted; g is a
spring bearing the valve f upwards with a force sufficient to resist a moderate
pressure in the cylinder a, but yielding to a considerable pressure; h is a bolt
fitted to slide freely in the cylinder bottom, with a collar to prevent its rising
above a certain height, and a spiral spring bearing it upwards; k is a screw
cap which serves as a guide for the end of the bolt h, and also to adjust the
force of the spiral spring.
The action of the apparatus is as follows:-The spiral spring being
adjusted so that the bolt h supports the piston b, a charge of inflammable
mixture introduced by the valves e into the space below the piston is
ignited; the expansive force thus produced closes the valves at e and f,
and drives upwards the piston b, and this piston drives before it a charge of
air through the valve c¹ into the vessel c. The propulsive force which drove
the piston upwards being spent the valve c¹ closes; the piston 6 descends by
its own weight, forcing out the contents of the cylinder through the valve f,
which is supported by the spring g against such pressure as is caused by the
descent of the piston. The products of combustion thus discharged from the
cylinder pass to the flues of a boiler to generate steam; or they may be
employed to heat the air compressed as above described so as to expand its
volume or increase its pressure, and thus increase its energy or motive power.
For this purpose they may be caused to pass in contact with the sides or exterior
of the vessel containing it, or may be made to pass through tubes or flues
within it; or their heat may be utilized in other ways. During the descent
of the piston 6 the valve d opens, and air entering through this valve fills the
cylinder above the piston. The piston approaching the bottom of the cylinder
with a certain momentum pushes the bolt h downwards until the compression
of the spiral spring is sufficient to stop it, and the strength of the spring is
adjusted so as to effect this when the piston is at the bottom of the cylinder.
The piston having reached the bottom, and its momentum being expended, the
spring lifts it to the height determined by the range of thesliding bolt h; during
this lifting the valve f being closed by the spring g air and combustible fluid
enter by the valves at e into the space below the piston, the flow of those
substances being regulated by stop-cocks, so that they enter the cylinder in the

page_text: proportion desired. When the requisite quantity is admitted the mixture is
ignited by an electric spark or otherwise, and the expansion produced by the
combustion again closes the valvesat e and f,and propels up wards the piston b,
which drives the air in the upper part of the cylinder before it into the
chamber c, the valve d being closed by the pressure. The piston having
reached the top of the cylinder the operation described is ready to be repeated.
In the form of apparatus described above the return of the piston is effected
by its weight,and accordingly the cylinder must be placed with its axis vertical.
Figure 2 represents the longitudinal section of an apparatus in which the
return of the piston is effected in a different manner. In this Figure a is
the cylinder; b, the piston; c, the vessel or chamber for receiving the com-
pressed air with its valve c' as before; d is the valve for admitting air to the
cylinder, and e one of the valves for admitting air and inflammable fluid in
quantities regulated by stop-cocks in their respective passages; fis a double
seated spring valve, like that described with reference to Figure 1, but situated
at a distance from the end of the cylinder, determined by the thickness of the
piston b, the passage to f being just below the dotted line 6¹ which marks the
lower side of the piston 6 when it is at the upper end of the cylinder a; gis
a cylindrical ring having a lip i projecting inwards at each end, and having
holes through its side which when the ring is at the bottom of the cylinder, as
represented in the Figure, face the openings which admit the air and
inflammable fluid from the valves e; his a piston attached to a rod worked
by the machinery. This piston works freely within the ring 9 as far as the
lips permit it to move therein.
The action of the apparatus is as follows:-The piston 6 having been
forced to the end of the cylinder so that its under side is at the dotted line 61
the piston h is caused by the machinery to make a stroke forwards, and on
meeting the lip of the ring git carries the ring with it. The onward motion
of the piston h and ring g causes the contents of the cylinder to be expelled
through the valve f, which is kept open by its spring against the moderate
pressure resulting from this movement of the piston and ring. The fluid
issuing through the valve f is conveyed to boiler flues or elsewhere, so that its
heat may be utilized, as described in reference to Figure 1. When the front
of the piston h has reached b' it is caused to return, the valve f being closed
by its spring, and the piston 6 being caused to follow h by the pressure of air
entering behind 6 into the cylinder by the valve d. When the ring g reaches
the bottom of the cylinder the piston b is stopped by it, but the piston h
continues to move within the ring now stationary. The inflammable mixture
enters by the valves at e into the space within the ring and between the two

page_text: pistons. This mixtre being ignited the piston 6 is driven forwards, forcing
the air in front of it through the valve c¹ into the chamber c, the pressure
thus produced closing the valve f against its spring. When the piston b
has reached the end of the cylinder the operation is ready to be repeated. In
both the forms of apparatus above described more than one cylinder can be
employed in connection with one engine. Fluid which has done work in the
engine can be introduced instead of air into the cylinder and compressed by
the piston. The cylinder or cylinders may be immersed in water within a
boiler, or may be cooled by a water jacket.
b
Figure 3 represents a section and Figure 4 a sectional plan of apparatus.
a is an
for obtaining inflammable gas from coal or other carbonaceous fuel.
annular chamber or oven formed between a cylindrical outer wall a¹ and a
cylindrical inner wall a², which is built upon an iron framing & supported on a
central column 6¹. The bottom of the annular chamber a consists of an iron
ring c which may be covered with tile or paving of any suitable refractory
material, and which is supported on arms radiating from a central boss c¹;
this boss embraces the column 61 and bears on a collar formed on that column,
so that it can be made to revolve freely thereon by means of bevil gearing, as
represented in the Figure, or by other convenient mechanism, the object
being to give the ring c a slow continuous rotary motion in the direction of
the arrow.
A curved wall a³ extends across the annular chamber a, and
immediately in front of it an opening is made in the outer wall a¹ so as to
form a passage of easy curvature from the chamber a to a furnace d built at
the side of the oven. This furnace is fitted with fire and ash-pit doors
provided with valves or openings, through which a regulated supply of air can
be admitted to the furnace. e is a fuel hopper or box placed immediately
behind the cross wall a³. This box is open at bottom to the chamber a, its
lower edge extending downwards to a certain distance from the surface of the
revolving floor c so as to leave room for a certain thickness of fuel upon the
floor to pass the lower lip of the box. The top of the box e is covered by a
lid, which can be made air-tight by means of a sand or water joint, such as is
ordinarily used in gas purifiers. f is a pipe leading from the top of the
annular chamber a to a gasometer or other receptacle for the inflammable
gas.
The action of the apparatus is as follows:-The fuel box e being charged
with coal or other carbonaceous fuel the annular plate or floor c is caused to
revolve slowly in the direction of the arrow, each part of it receiving as it
passes e a supply of fuel laid upon it in a stratum of suitable thickness. As
this fuel is brought round to the cross wall a³ it is swept or shunted on to the

page_text: bars of the furnace d. When the revolving plate and furnace are thus
charged with fuel the furnace is kindled, and supplied with air sufficient to
effect full combustion of the fuel upon the bars, and thus generate carbonio
acid. The heated products of combustion pass over the surface of the fuel
on c in a direction opposite to the arrow, and in doing this produce carbonic
oxide, and cause the disengagement of such other inflammable gases as the
fuel contains; the gas produced finally issues by the pipe f. The fuel hopper e
is charged from time to time with fresh fuel, and the ash-pit of the furnace d
is from time to time cleared. The continuous revolution of the floor c effects
the continuous exposure of fresh fuel to the action of the heated products of
combustion and the continuous supply of fuel more or less coked to the
furnace d. Sometimes instead of making the top of the annular chamber a
plain and smooth I make it with frequent breaks or bridges projecting down-
wards so as to cause the products of combustion in their progress from d
towards f to beat down upon the surface of the fuel stratum.
Having thus described the nature of my Invention,and in what manner the
same is to be performed, I would have it understood that I do not limit
myself to the details described or represented in the Drawings, as these may
be varied without departing from the principles and modes of action which
they are intended to effect.
In witness whereof, I, the said Matthew Piers Watt Boulton, have
hereunto set my hand and seal, this Second day of January, in the
year of our Lord One thousand eight hundred and sixty-eight.
M. P. W. BOULTON. (L.S.)