IMPROVEMENTS IN IN OBTAINING MOTIVE POWER BY HEAT
Year: 1865

page_text: LETTERS PATENT to Matthew Piers Watt Boulton, of Tew Park,
Oxfordshire, for the Invention of "IMPROVEMENTS IN
IN OBTAINING MOTIVE
POWER BY HEAT."
Sealed the 30th January 1866, and dated the 1st August 1865.
FROVISIONAL SPECIFICATION left by the said Matthew Piers Watt
Boulton at the Office of the Commissioners of Patents, with his
Petition, on the 1st August 1865.
I, MATTHEW PIERS WATT BOULTON, of Tew Park, Oxfordshire, do
hereby declare the nature of the said lavention for "IMPROVEMENTS IN
OBTAINING MOTIVE POWER BY HEAT," to be as follows:-
Ordinarily in engines worked by the ignition of a mixture of air with
gas or inflammable fluid a large portion of the heat produced passes
away in the products of combustion without being converted into
mechanical agency. In order to utilize a larger portion of the heat the.
following method may be adopted :-The mixture of air and inflammable
fluid having been admitted into the cylinder and ignited the products of
combustion as they expand are caused to traverse a narrow passage or
narrow passages in which a large wetted surface is exposed to their

page_text: action. Heating the water on this surface they generate steam, and the
steam thus produced co-operates with them in driving the piston.
The form and position of the passage and passages may be varied in
many different ways. One arrangement is as follows:-A cylindrical
body is placed within the cylinder, between which and the cylinder a
narrow passage is left. The sides of this passage are wetted, and the
heated gases traverse this passage. Similarly within the cylindrical
body may be other concentric passages, the sides of which are wetted,
and through which the gases pass. The cylindrical body is driven on the
return stroke through the chamber, which receives the charge of in-
flammable fluid, driving out the products of combustion, except those
which remain in the passages. On the forward stroke the body returns
through this space. If the air and inflammable fluid enter the cylinder
at high pressure it is forced forward by these. If they enter at atmos-
pheric pressure it is moved by a spring or by its own weight, or by the
action of the machinery. The sides of the passages are wetted by in-
jecting water upon them. The injection may take place during a portion
of the stroke. Otherwise water may be injected on wire gauze or
material perforated with numerous holes, the heated products of com-
bustion being forced through this as they expand, and carrying with
them particles of the water in the state of spray, which they heat and
convert into steam. Otherwise the surfaces may be wetted by causing
them to be immersed in a vessel containing water from which they are
afterwards drawn out. Rods, bars, plates, or pieces of other forms,
between which are narrow passages, are caused by the engine to per-
form a reciprocating movement. On descending they enter a vessel of
water, and on ascending they expose a wetted surface to the action of
the heated gases, which are caused to traverse the narrow passages
between them. The vessel need not at any time contain 'more water
than is evaporated by the action of the gases during each stroke.
Instead of a reciprocating movement a continuous rotary movement
may be employed. Discs or circular pieces are caused to revolve through
a vessel containing water, thus becoming wetted and exposing a wetted
surface. The gases traverse narrow passages between the discs or cir-
cular pieces heating the water upon them and generating steam.
In order to prevent accumulation of deposit on the plates or discs
they may work against or near a scraper, which scrapes off the deposit
when it exceeds a certain thickness. The deposit so scraped off falls into
a receptacle prepared for it, and is removed from time to time. In-
stead of passing in contact with wetted surfaces, the products of com-
bustion may pass in contact with the external surfaces of tubes or
vessels containing in their interior water, thus generating steam at any

page_text: desired pressure. The steam thus generated is admitted during a portion
of the stroke to mix with the products of combustion, co-operating with
them in driving the piston which works the machinery. The chamber
containing the narrow passages which the heated gases are caused to
traverse may be at the side of the cylinder, opening into this by two
passages.
For driving out the products of combustion in the cylinder the fol-
lowing arrangement may be adopted :-Two pistons are employed, one of
these is connected with the machinery, the other works in the space
which receives the charge of inflammable fluid. This latter piston is
larger and works in a larger cylinder than the former. At the end of
the return or exhaust stroke the larger piston is driven by the working
piston to the end of the cylinder in which it works, driving out from
this the products of combustion. Air entering through an aperture
behind it fills the space not filled by the smaller piston. On the for-
ward stroke the larger piston is brought back, being moved either by
the pressure of the entering gases, or by a spring, or by its own weight.
The air previously admitted in the space not filled by the smaller piston
is driven out again. When the piston reaches the end of the larger
cylinder it is arrested and intercepts direct communication between the
space where the charge of imflammable fluid is admitted and the piston
connected with the machinery. Thus the products of combustion can-
not pass directly from one to the other, but are forced to traverse the
narrow passages in which the wetted surfaces are exposed to their
action. Water might be injected into the chamber in which the gases
are ignited, but it is not desirable that the gases during ignition should
be exposed to cooling agencies, as this tends to interfere with com-
plete combustion.
In the arrangement described the gases during
ignition are not in contact with water, but after ignition the products
of combustion come in contact with the wetted surfaces and generate
steam. The gaseous matter in the passages acts as a cushion tending to
prevent shock to the machinery by the rapid increase of pressure pro-
duced by the ignition of the gases. By increasing the size of the passages
this cushion can be made as large as is desired.
The arrangement above described may be employed without, the
wetted surfaces for the purpose of obtaining a cushion of air interposed
between the ignited gases, and the piston which drives the machinery
in order to prevent shock to the latter. As a further means of obviating
shock to the machinery, it may be provided that the gases immediately
after ignition pass through a passage so narrow that they are wire drawn,
and accordingly produce less pressure on the other side of the contracted
passage than on that on which the ignition takes place. The pressure

page_text: caused by the expansion of the gases moves a valve or moveable piece,
the movement of which removes the contraction of this passage, thus
putting an end to the wire-drawing action after it has produced the
effect desired. Or the moveable piece may be moved by the action of
the engine.
Otherwise the following method may be employed:-After the ignition
of the gases in the chamber into which they are introduced, a piston or
plunger moves through them forcing them out at one end of the chamber,
and drawing them in at the other, as is done by the plunger in Stir-
ling's air engine; the gases being thus made to pass through the chamber
in which the wetted surfaces are exposed to their action. The steam
thus generated passes along with the gases to the cylinder in which the
piston which drives the machinery works and acts together with them
upon it. The plunger or piston which gives movement, as above de-
scribed, to the ignited gases is worked by the engine, and at the proper
time it drives out the products of combustion from the chamber in which
it works.
This method and that previously described may be partly combined,
that is to say, the gases may be forced through some wetted passages by
means of a plunger, while they pass through others in virtue of their
expansion. Instead of employing the pressure of the gases and steam
to work directly the piston which drives the engine, they may be em-
ployed to drive a piston which compresses air, the air thus compressed
being employed to work the piston which drives the machinery. It is
not necessary to drive the products of combustion during the exhaust
stroke through the narrow passages. Two eduction valves may be em-
ployed on either side of these passages; the gases on one side being dis-
charged through one of these, and those on the other side through the
other. The inflammable mixture may be ignited by means of the electric
spark. This spark may be produced either by a voltaic pile or battery,
or by frictional electricity, or by magnetic electricity. The frictional
electricity may be produced mechanically by motion produced by the
engine, or by a jet of steam. The magnetic electricity may be produced
by causing an armature to revolve near the poles of a magnet, this move-
ment being produced by the engine. The contact which produces the
spark and causes ignition of the gases may be produced by means of a
rod worked by the larger piston, which completes the circuit
at the moment desired. The engine may be double acting,
the parts on either side of the piston which works the machinery being
similar. The cylinder may be cooled externally, as also the valves and
parts connected with them to any extent desired by water. The water
thus heated may be injected on the surfaces exposed to the action of

page_text: be
the heated gases and turned into steam; or otherwise this water may
converted into steam and used in the cylinder along with the products of
combustion. In order to keep cool the induction valves, through which
the air and gas are admitted into the cylinder, these valves are not
placed at the extremity of the passages in which they respectively work.
When, therefore, the inflammable mixture is ignited a certain portion
of air and gas rentains in the passages unignited, being interposed be-
tween the ignited gases and the valves, and protecting the latter from
the heat.
In an engine of the above description various kinds of gas or in-
flammable fluid may be used, such as hydrogen, carburetted hydrogen,
carbonic oxide, the gases or vapours obtained by subjecting to heat
petroleum or hydrocarbons. Inflammable gas for the purpose may be
obtained in the following way:-A quantity of air insufficient for com-
plete combustion is passed through carbonaceous fuel, such as coke,
coal, wood, so that the carbon which, if the combustion were complete,
would unite with the oxygen in the form of carbonic acid unites with
it in the form of carbonic oxide. The gases thus obtained having the
heat due to the imperfect combustion are employed to generate steam
by passing in contact with the exterior of a boiler. The steam thus
produced is used for the production of motive power. The gases may
be further cooled by being passed through water, by which process they
are also freed from dust and impurities. The water thus heated may
be used subsequently for conversion into steam. The gases thus ob
tained being thus cooled and purified are fit to be used in an engine such
as above described. Instead of mixing the inflammable gas in the
chamber with atmospheric air it may be mixed with oxygen. The oxygen
may be generated under pressure from a mixture of chloride of lime
with peroxide of cobalt, or from sulphate of lime acted on with silex
under heat, and may enter the combustion chamber at the pressure
desired; or a forcing apparatus may be employed to force in the oxygen,
and this method may be adopted in all cases in which it is desired to
employ products of combustion for the production of motive power.
When heat is employed to produce motive power a portion of the heat
may be employed to generate electricity, and thus produce electro-
motive force, while the portion not so converted may be employed, to
generate steam or to heat aeriform fluid used in a steam or caloric
engine.
The following arrangement may be adopted; heat is applied to cer-
tain parts of metals composing a thermo-electric pile battery or appa-
ratus. From other parts of these metals heat is abstracted by water con-
tained in a boiler, a difference of temperature being thus established

page_text: between the two parts of the apparatus. A certain portion of the heat
in its passage through the metal is converted into electricty, and the
force thus produced is employed to work an electro-motive engine.
That portion of the heat which is not converted into electricity imparts
heat to the water in the boiler, generating steam which is used to work
a steam engine. If desired the electricity obtained may be employed to
decompose water, the oxygen and hydrogen thus generated being used
to cause combustion in a close vessel and to produce motive power in
this way.
That part of the metals whence heat is abstracted may impart heat
to the water in the boiler through some substance which conducts heat
but does not conduct electricity. Otherwise, this part of the metals
may be immersed in the water, the metals at each point of immersion
being in a separate compartment, the sides of which are formed of
material which does not conduct electricity, so that the water cannot
conduct electricity from one part of the apparatus to the other. The
water needed to supply that which passes away by evaporation may fall
downwards into the compartments from holes or jets in a vessel above,
or may otherwise be introduced so as not to cause communication of
electricity from one vessel to the other. In order to prevent oxidation
of the metals employed in the thermo-electric pile or battery where they
are exposed to heat, these metals may be heated by means of a heated
liquid such as metallic oxides, chlorides, sulphides, salts, and earthy
materials in a state of fusion. This liquid may be heated by passing
through it gaseous products of combustion, these not coming in contact
with the metals. In this case, as in the preceding, compartments may
be used, which prevent the liquid from giving passage to the electricity.
Again, the metals may be heated by means of a current of heated
nitrogen, carbonic oxide, or other gas incapable of acting upon them.
The gas may be heated by means of heated liquid in the manner which
I have described in previous Specifications. It may also be heated by
means of rods, plates or bodies, to which a reciprocating motion is given
causing them alternately to dip into the liquid and to rise out of it;
similarly it may be heated by means of discs or circular pieces revolving
so that part of them is constantly passing through the liquid and re-
ceiving heat from it while part is imparting heat to the gases.
The above modes of applying heat to the thermo-electric apparatus
may be employed in whatever manner that apparatus may be used.
A similar mode of applying heat may be employed when it is desired
to superheat steam to a high temperature, that is to say, the pipes or
passages in which the steam is heated are heated on the exterior by
means of a liquid or a gaseous fluid, which is incapable of exercising a

page_text: destructive action on the pipes at a high temperature. And the mode of
heating the liquid or gaseous fluid employed for this purpose may be such
as above described. Also a similar method of applying heat may be used
when it is desired to convert petroleum oil, hydrocarbons, or other sub-
stances into inflammable gas or vapour. The pipes or chambers in
which the substance is subjected to heat may be heated in the manner
above described.
SPECIFICATION in pursuance of the conditions of the Letters l'atent, filed
by the said Matthew Piers Watt Boulton in the Great Seal Patent
Office on the 31st January 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MATTHEW
PIERS WATT BOULTON, of Tew Park, Oxfordshire, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of August, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-ninth 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, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
OBTAINING MOTIVE POWER BY HEAT," upon the condition (amongst others) that
I, the said Matthew Piers Watt Boulton, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
IN
NOW KNOW YE, that 1, 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 ascer-
tained in and by the following statement thereof, that is to say-
Ordinarily in engines worked by the ignition of a mixture of air with
gas or inflammable fluid, a large portion of the heat produced passes
away without being converted into mechanical agency or effect. In

page_text: order to utilize a larger portion of the heat, the following method may
be adopted-The mixture of air and inflammable fluid having been
admitted into the cylinder designed for its reception and ignited, the
products of combustion are caused to traverse a narrow passage or
narrow passages in which a wetted surface is exposed to their action.
Heating the water on this surface they generate steam, and the steam
thus produced co-operates with them in driving the piston of the engine.
The form and position of the passage and passages may be varied in
many different ways. One arrangement is as follows;-A number of
bodies, rods, bars, plates or pieces of other forms between which are
narrow passages are caused by the engine to perform a reciprocating
movement. On descending they enter a vessel of water and on ascend-
ing they expose a wetted surface to the action of the heated gases which
are caused to traverse the narrow passages between them. Instead of
a reciprocating movement a continuous rotary movement may be em-
ployed. Discs or circular pieces are caused to revolve in a vessel which
they nearly fit. The surfaces of these discs are wetted, and the heated
gases are caused to pass between the discs evaporating the water on
their surface. Instead of passing in contact with wetted surfaces the
products of combustion may pass in contact with the external surfaces of
tubes or vessels containing in their interior water, thus generating steam
at any
desired pressure. The steam thus generated is admitted during a
portion of the stroke to mix with the products of combustion co-operat-
ing with them in driving the piston which works the machinery.
One method of arranging the parts of the engine is shewn in Figure 1.
Here A, A, is a cylinder into which an inflammable mixture, such as
a mixture of air and gas, in suitable proportions is introduced; B is a
larger cylinder in which a piston works connected with the machinery;
C is the evaporating chamber containing numerous plates or bodies whose
surfaces are wetted, narrow passages for the passage of air or gas being
left between these. Otherwise this chamber may contain numerous
channels within which is water communicating with a close vessel, and
capable of freely circulating, the narrow passages for the passage of the
air or gas being between the external sides of the channels containing
this water. At a', a, b, c, d, and e are valves. When the piston P¹
moves downwards in the cylinder A, A, the inflammable mixture enters
that cylinder through passages provided for that purpose, of which 6 is
When the piston P¹ has performed its downward stroke the valves
at b and c are closed and the inflammable mixture is ignited. At the
same time or immediately subsequently the valves at a¹, a², and d are
opened. The gases entering the cylinder B, B, through the passage at d
press on the piston P' and cause it to ascend, the eduction valve at e
one.

page_text: being closed. At the same time the piston P' is caused to ascend in the
cylinder A, A, either directly by connection with the machinery or by
some power brought to bear upon it by means of the machinery. In the
former case it may be connected by a crank with the same axis with
which the piston P is connected. As the piston P' ascends it causes the
products of combustion in the cylinder A, A, to pass out of the upper
part of the cylinder through the evaporating chamber C, in which are
the narrow passages, and to re-enter the cylinder A, A, below the piston
P. As the heated products of combustion pass through the evaporating
chamber they generate steam; if they pass between wetted surfaces this
steam mingles with them, and entering the cylinder B, B, along with
them co-operates with them in working the piston P. If they heat
the external surfaces of vessels containing water, then they generate
steam in the vessel of which these channels form part at any required
pressure, and this steam is either employed along with them in the
cylinder B, B, or is employed to perform work in a cylinder apart from
them. On the return stroke the valves a', a³, and d are closed. The
piston P descending drives out the gaseous matter in the cylinder B, B,
through an eduction valve in the passage e. The piston P¹ descending
drives out the gaseous matter in the cylinder A, A, through an eduction
valve in the passage c, while a fresh charge of the inflammable mixture
is introduced into the upper part of the cylinder A, A, through the in-
ducation valves of that cylinder.. The operation previously described is
then ready to be repeated.
If it is desired the products of combustion may be caused to traverse
the passages, and to generate all the steam which they are capable of
producing before communication is opened between them and the work-
ing cylinder. By employing a similar arrangement of parts in connec-
tion with the upper end of the cylinder B, B, the engine is made double-
acting. In an engine such as above described, while the temperature of
the ignited gases is very high the temperature of the fluid in the working
cylinder may exceed but little that of boiling water, and thus no difli-
culty is caused by heat in working the piston in this cylinder. The
temperature employed in this cylinder can be regulated by adjusting the
size of the evaporating chamber, and the quantity of water evaporated
therein. In those parts of the engine which contain highly heated fluid,
the valves and other parts can be cooled to any extent desired by water.
The inflammable mixture may be ignited by means of the electric spark.
This may be produced by a voltaic battery; or otherwise it may be pro-
duced by causing a suitably prepared armature to revolve near the poles
of a magnet, as is done in various magneto-electric machines. The in-

page_text: flammable mixture of gas and air used in an air engine such as above
described may be admitted into the combustion chamber A, A, Figure
1, at the atmospheric pressure, the air in this case being drawn out of
the atmosphere; or otherwise the gas and air may be introduced into the
combustion chamber at high pressure, the air being compressed by a
pump worked by the engine. In this case the force of the fluid entering
the combustion chamber A, A, and acting on the piston which works in
that chamber co-operates in driving the machinery or performing work.
The heat imparted to water by those parts of the engine which are kept
cool by water may be utilized by employing the water thus heated in the
evaporating chamber. If petroleum, hydrocarbons, or other liquids are
used in the engine as fuel, the heat abstracted from these parts of the
vessels, or a portion of it, may be used in heating these liquids. In an
engine of the above description various kinds of gas or inflammable fluid
may be used, such as hydrogen, carburetted hydrogen, carbonic oxide,
the gases or vapours obtained by subjecting to heat petroleum or hydro-
carbons. The gases resulting from the imperfect combustion of coal
or carbonaceous fuel may be employed. The heat of these may be re-
duced and utilized previous to their admission into the cylinder of the
engine. In an engine of the nature described oxygen generated under
pressure may be employed instead of air. In this case there is cost in
obtaining the oxygen, but on the other hand a smaller quantity of the
combustible matter employed produces a more powerful effect. When
heat is employed to produce motive power, a portion of the heat may be
employed to generate electricity, and thus produce electro-motive force,
while the portion not so converted may be employed to generate steam,
or to heat aeriform fluid used in a steam or caloric engine.
The following arrangement may be adopted--Heat is applied to
certain parts of metals composing a thermo-electric pile battery or
apparatus. From other parts of these metals heat is abstracted by water
contained in a boiler, a difference of temperature being thus established
between the two parts of the apparatus. A certain portion of the heat
in its passage through the metal is converted into electricity, and the
force thus produced is employed to work an electro-motive engine.
That portion of the heat which is not converted into electricity imparts
heat to the water in the boiler generating steam, which is used to work
a steam engine. In order to prevent oxidation of the metals employed
in the thermo-electric pile or battery, where they are exposed to heat,
these metals may be heated by means of a heated liquid, such as metallic
oxides, chlorides, sulphides, salts, and earthy materials in a state of
fusion. This liquid may be heated by passing through it gaseous pro-
ducts of combustion, these not coming in contact with the metals.

page_text: When it is desired to superheat steam the following method may be em-
ployed-The pipes or passages in which the steam is heated are heated
on the exterior by a liquid which is incapable of exercising a destructive
action on the pipes at a high temperature, and the liquid may be heated
by causing to pass through it flame or gaseous products of combustion.
Similarly if it is
In Figure 2, A, A, represents pipes or passages in which steam is
superheated; B, B, B, B, is a vessel containing liquid C, C. Flame or
gascous products of combustion are passed through this liquid from the
pipe or passage D, D, and impart heat to it, which heat it imparts to
the steam in the superheating apparatus A, A, A, A. The liquid is of
such a nature as not to act injuriously on the metal or material com-
posing the pipes through which the steam passes. Aeriform fluid of any
description may be heated in a similar manner.
desired to convert petroleum oil or other liquid into vapour or into
gascous products, the liquid may be caused to flow into or through pipes
or passages heated in a similar manner. When aeriform fluid used in
working an engine is much expanded during performance of work, and
it is desired to render less unequal the force brought to bear upon the
engine, an arrangement may be employed for this purpose similar to
that called the "pneumatic equalizer." A shaft is made to revolve twice
as fast as the crank shaft, this shaft being connected with a piston in a
cylinder, so that the piston in this cylinder makes two strokes, while the
piston of the engine makes one. During the first part of the stroke of
the engine the piston previously mentioned compresses the air in the
cylinder in which it works, the resistance thus caused checking the move-
ment of the engine. During the latter part of the stroke of the engine
this air expands, performing work in aid of the movement of the engine.
Thus the force brought to bear upon the engine is rendered more
uniform. This mode of equalizing the force may be combined with
others which have been used, such as the using of the aeriform fluid
successively in two cylinders of different sectional areas, or the using
it successively in two portions of the same cylinder where surfaces of
different areas are exposed to its pressure, and by such a combination
the equalization may be rendered more perfect. Again, when aeriform
fluid is used at very high pressure, the piston on which it works may be
connected with the piston of a pump which compresses air at a much
lower pressure, the air thus compressed being employed to work the
engine. The two pistons may both be on the same rod.
What I claim is, the method of working an engine by introducing an
inflammable mixture of gas and air or other inflammable mixture into
a cylinder or vessel, and then causing the products of combustion re-
sulting from the ignition of that mixture to pass through narrow

page_text: passages, whose sides are wetted internally, or are in contact with water
externally, the steam thus produced co-operating with the products of
combustion to work the engine.
Also I claim the particular method described of carrying that process
into effect.
Also I claim the employment of a thermo-electrical apparatus com-
bined with the boiler of a steam engine, so that the heat not converted
into electricity in thermo-electrical apparatus passes into the water and
produces steam, this steam being employed for the production of
motive power.
I also claim the method of heating vessels for the purpose of heating
steam a aeriform fluid, described in respect to Figure 3 of the Drawings.
In witness whereof, I, the said Matthew Piers Watt Boulton, have
hereunto set my hand and seal, this Twentieth day of January,
in the year of our Lord One thousand eight hundred and sixty-
six.
M. P. W. BOULTON. (L.S.)