IMPROVEMENTS IN THERMO DYNAMIC ENGINES
Year: 1882

page_text: LETTERS PATENT to James Hargreaves of Widnes in the County of
Lancaster Chemical Engineer for an Invention of IMPROVEMENTS IN
THERMO DYNAMIC ENGINES
PROVISIONAL SPECIFICATION left by the said James Hargreaves at the
Office of the Commissioners of Patents on the 26th July 1882.
JAMES HARGREAVES, of Widnes, in the county of Lancaster, Chemical Engineer,
IMPROVEMENTS IN THERMO-DYNAMIC ENGINES
My improvements relate to internally heated regenerative caloric engines in
which solid, liquid, or gaseous fuel may be used as the source of heat and
consequently of motive power. The combustion of fuel inside the working
cylinder, or in a vessel contiguous thereto, has frequently been proposed, amongst
others, by Anderson and Brayton.
The use of a regenerator to restore to the working fluid the heat from a previous
charge of the working fluid is also well known and has been described by Stirling,
Ericsson, M. P. W. Boulton and others.
Some of the inventions before referred to have yielded an amount of mechanical
energy, in proportion to the fuel employed, greatly in excess of that yielded by the
best designed steam engines then in use, but have generally been found
impracticable in consequence of overbeating, or because the engines were too bulky
or complicated in proportion to the power yielded; and the object of my invention
is to avoid these practical disadvantages
In carrying my invention into practice I provide a working cylinder in which a
working piston is forced forward by the pressure of heated air and vapour or
heated air and gas or a mixture of all of these, which latter is preferred. The
heated air and vapour or gas is for brevity and for the purpose of this specification
hereafter called the "working fluid." A compressing pump is used to compress
air; the said air is forced into a reservoir, which reservoir may be also used as a
saturating vessel, where the said air is saturated with vapour from water which
has been heated by the heat rejected from the said working fluid and to assist the

page_text: said saturation I use mechanical means to expose a large surface of water to the
air. A convenient means of doing this is by sheets of wire gauze alternately
dipped into the said water and raised amongst the air which is to be saturated with
vapour.
In some modifications of my said invention I add volatile hydrocarbons to the
said water so as to form a combustible or explosive mixture in the said reservoir
and saturator or I pump combustible gas along with the said air when I work by
explosive rather than ordinary combustion. But when I work by combustion
instead of explosion I use a supplementary gas pump to force the said
combustible gas or inflammable mixture of air and hydrocarbon vapours into a
separate reservoir.
A regenerator is provided through which the said compressed saturated air passes
when on its way to the working cylinder and through which the exhausted working
fluid also passes when leaving the said working cylinder. By this means I superheat
the air used in combustion.
When burning solid fuel I provide a furnace into which the said solid fuel is
placed and force the air which has been heated by the said regenerator through the
said furnace but provide valves by which the used working fluid shall be made to
pass into and through the said regenerator without passing through the said
furnace.
When using liquid fuel I in some cases cause the said liquid fuel to flow into
the said furnace or a modification of such furnace adapted to the combustion of
liquid fuel,
To keep the neck of the working cylinder cool and at the same time to render
available the abstracted heat to produce motive power I cause all or a portion of
the air or of the combustible gas or vapour or combustible liquid to enter the
working cylinder at or near the open end of the said working cylinder and pass
along between the working piston and the inside of the working cylinder so as to
abstract heat therefrom before arriving at the space where combustion or explosion
takes place For this purpose the body of the working cylinder is made slightly
larger than the working piston to allow the necessary passage space. The end of
the working piston which is inside the working cylinder is covered with a perforated
plate through which the said gaseous or vapourized fuel issues in jets and is
burned. The aforesaid regenerator may in some cases be replaced by a multitubular
vessel in which water or other fluid is heated by the exhaust working fluid and the
vapour therefrom may be used to saturate the aforesaid compressed air with an
increased quantity of vapour.
Suitable valves are provided to regulate the inlet and outlet of the gases or
vapours employed and automatic check valves are also provided to prevent the
working fluid from rushing back into the air or gas reservoirs when the
pressure in the said working cylinder is higher than in the said reservoir or
reservoirs.
To maintain as much as practicable the temperature of the working fluid without
weakening the working cylinder I place in the said working cylinder a liner with
grooves or elevations on its outer surface which prevents the said liner from coming
into continuous close contact with the sides of the said working cylinder and I cause
some of the said compressed air, gas or liquid when on its way to the combustion
or explosion space in the said working cylinder to pass along the space existing
between the said liner and the working cylinder.
It will be evident that the explosion or combustion in my cylinder may be effected
by any known or convenient means or appliances.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent and of an
Order of the Lord Chancellor filed by the said James Hargreaves in the
Great Seal Patent Office on the 6th February 1883.
JAMES HARGREAVES of Widnes in the County of Lancaster, Chemical Engineer
"IMPROVEMENTS IN THERMO-DYNAMIC ENGINES
"
My improvements relate to internally heated regenerative caloric engines in
which solid liquid or gaseous fuel is used as the source of heat and consequently of
motive power.
The combustion of fuel inside the working cylinder or in a vessel
contiguous thereto has frequently been proposed, amongst others by Anderson and
Brayton.
The use of a regenerator to restore to the working fluid-the heat from a previous
charge of the working fluid is also well known and has been described by Stirling.
Ericsson, W. P. W. Boulton and others.
Some of the inventions before referred to have yielded an amount of mechanical
energy in proportion to the fuel employed greatly in excess of that yielded by the
best designed steam engines then in use, but have generally been found imprac-
ticable in consequence of over heating or because the engines were too bulky or
complicated in proportion to the power yielded and the object of my invention is
to avoid these practical disadvantages.
A
In carrying my invention into practice I provide a working cylinder in which
a working piston is forced forward by the pressure of heated air and water vapour
or heated air and gas or a mixture of all these which latter is preferred. The
heated air and water vapour or heated air and gas or these together are for brevity
and for the purpose of this specification hereafter called the "working fluid."
compressing pump is used to compress air, the said air is forced into a reservoir
which reservoir may be also used as a saturating vessel where the said air is
saturated with vapour from water which has been heated by the heat rejected
from the said working fluid and to assist the said saturation I use mechanical ineans
to expose a large surface of water to the air. A convenient means of doing this is
by sheets of wire gauze alternately dipped into the said water and raised amongst
the air which is to be saturated with vapour.
In some modifications of my said invention I add volatile hydro-carbons to the
said water so as to form a combustible or explosive mixture in the said reservoir
and saturator or I pump combustible gas along with the said air when I work by
explosive rather than ordinary combustion, But when I work by combustion
instead of explosion I use a supplementary gas pump to force the said combustible
gas or inflammable mixture of air and hydro carbon vapours into a separate reservoir.
A regenerator is provided through which the said compressed saturated air passes
when on its way to the working cylinder and through which the exhausted working
fluid also passes when leaving the said working cylinder. By this means I super-
heat the air used in combustion.
When burning solid fuel I provide a furnace into which the said solid fuel is
placed and force the air which has been, heated by the said regenerator through the
said furnace but provide valves by which the used working fluid shall be made to
pass into and through the said re-generator without passing through the said
furnace.
When using liquid fuel I in some cases cause the said liquid fuel to flow into the
said furnace or a modification of such furnace adapted to the combustion of liquid fuel.

page_text: To keep the neck of the working cylinder cool and at the same time to render
available the abstracted heat to produce motive power I cause all or a portion of
the air or of the combustible gas or vapour or combustible liquid to enter the
working cylinder at or near the open end of the said working cylinder and pass
along between the working piston and the inside of the working cylinder so as to
abstract beat therefrom before arriving at the space where combustion or explosion
takes place. By the open end of the working cylinder I mean the end through
which the working piston passes when the engine is at work. For this purpose
(that is for keeping the neck cool) the body of the working cylinder is made slightly
larger than the working piston to allow the necessary passage space. The end of
the working piston which is inside the working cylinder is covered with a per-
forated plate through which the said gaseous or vapourized fuel issues in jets and
is burned. The aforesaid regenerator may in some cases be replaced by a multi-
tubular vessel in which water or other fluid is heated by the exhaust-working fluid,
and the vapour therefrom may be used to saturate the aforesaid compressed air with
an increased quantity of vapour.
Suitable valves are provided to regulate the inlet and outlet of the gases or
vapours employed and automatic check valves are also provided to prevent the
working fluid from rushing back into the air or gas reservoirs when the pressure
in the said working cylinder is higher than in the said reservoir or reservoirs.
To maintain as much as practicable the temperature of the working fluid
without weakening the working cylinder I place in the said working cylinder a
liner with grooves or elevations on its outer surface which prevent the said liner
from coming into continuous close contact with the sides of the said working
cylinder and I cause some of the said compressed air, gas or liquid when on its way
to the combustion or explosion, space in the said working cylinder to pass along
the space existing between the said liner and the working cylinder.
It will be evident that the explosion or combustion in my cylinder may be
effected by any. known or convenient means or appliances.
The thermo-dynamic engine herein described is applicable under a large number of
forms and many methods of generating heat, and I have shown in the accompanying
drawings several of the principal ones to show the nature and principle of my said
invention. But I do not confine myself to the modifications or to the proportions
of the various parts inasmuch as the temperature and physical properties of the
working fluid employed have considerable influence upon the relative dimensions
of the compressing and working cylinders. Where the temperature obtained by
combustion is high or a large proportion of water vapour is present the dimensions
of the working cylinder may be increased.
The
In sheet I figs I, II & III are outside elevations and plan of an engine for
using combustible gas as a source of heat and power.
A compresser by which the
air is compressed and forced into the air reservoir B. C is the combustible gas
reservoir in which is enclosed the gas compresser. D the regenerator and valve
box. E countershaft carrying eccentrics which open the working valves.
said working valves are closed by means of springs attached to the valve levers.
To avoid complication the said springs are not shown in the drawings. F water
box constantly supplied. The water is taken by the compresser along with air
and such water serves to keep the compresser cool and to supply the vapour
necessary for saturating as more particularly appears hereafter. a cam which opens
the inlet port. b exhaust cam. c cam controlling the supply of the combustible
gas to the working cylinder d the working piston. e air compresser piston, and
f gas compresser piston. The pumps and valves for the compression of air and gas
are of any ordinary or suitable kind and need no special description. 9 in figs I
and II is a pulley driven by the the cam shaft by means of a belt. The said pulley
causes a wire cage to revolve inside the reservoir B in such manner as to expose a
large surface to the water in the said reservoir and to the air in such reservoir.
For convenience in showing the position of the parts situated below the pulley g

page_text: said pulley is omitted in fig III and in fig I the countershaft is drawn as at the
section " n. n
to show the inlet cam a in position when admitting air.
Figs IV and V on sheet 2 show respectively longitudinal and transverse sections
of my said engine. fig V being at the line XX. The same letters denote the same
parts as in figs I. II and III. the passage from the air compressing pump
to the reservoir B. The said reservoir B contains revolving cage h of wire
gauze or other suitable material which revolves and exposes the water in the
said reservoir B to contact with the compressed air, by which means water vapour
is diffused amongst the said compressed air and adds its own pressure to that of
the said compressed air. The said compressed air is passed into the working
cylinder through.the inlet valve j. A check valve k is placed above the said inlet
valve to prevent the air from rushing back into the reservoir B during explosion
or combustion. The compressed and saturated air passed through the regenerator
which is packed with wire gauze, when the said compressed air enters the interior
of the working cylinder m. On the outstroke the piston is pushed forward by the
pressure of the compressed air until the heated point of the firing rod "o" is
outside the socket p in the working piston d. The said firing rod is kept heated
by a blow pipe, which maintains a platinum thimble at the extremity of the said
firing rod at a red heat. When the said platinum thimble is exposed to the
mixture of gas and air an explosion or combustion takes place and thereupon the
piston d is forced outwards after which the port is opened and the products of
explosion or combustion allowed to escape through the regenerator l. The
combustible gas forced into the reservoir c by the piston f passes through the check
valves and past the slide valve t through the passage to a passage which
encircles the neck of the working cylinder and then passes along a narrow space w
between the body of the working piston d and a liner y which latter forms the
interior surface of the working cylinder m The said space being in a cylinder
200 Millimetres in diameter only one millimetre between the inside of the liner
and the body of the piston After passing through the said space w the gas enters
the cylinder through the perforated plate 1 at the end of the piston. The said
liner y may also have a series of ribs as marked at x leaving a passage along the
whole length so that a part of the gas passes along the spaces between the said
ribs and enters the cylinder at the point z In passing along the said liner the
entering gas becomes heated before mixing with the air.
When
In the foregoing description the heating of the water in the saturating reservoir
is effected by heat which passes through the liner and side of the working cylinder
Figs VI and VII are sectional views the latter at y y of a modification of my
engine wherein the heating of the mixture of air and combustible gas is effected
by the liner and the heating of the water in the saturator by the exhaust gases.
In this no separate gas pump need be used. The combustible gas is allowed to
enter the air compresser along with the air and be compressed with it, or petroleum
or other volatile hydro-carbon may be pumped into the reservoir B.
volatile hydro-carbon is diffused through the air so as to form an explosive
mixture such mixture passes the checks and working valve t through passage u
and annular passage then through the narrow space w and the spaces
between the longitudinal ribs of the liner y into the working cylinder m at c.
The mixture is then fired by the firing rod o as explained in the description of
figs IV and V. After firing the mixture the working piston completes its out-
stroke; the exhaust valve is then opened and the burnt gases pass through the
tubes "4" and give up their heat to the water in the reservoir B.
Figs VIII and IX show attachment to my said engine for using solid fuel in
which is the inlet valve, check valve to prevent air from rushing backward to
the reservoir B. the regenerator preferably filled with metallic balls to allow the
dust to pass freely through The compressed and saturated air after passing the
said regenerator raises the valve 5 and passes through the revolving grate "6"
and clay lined fire place, 7 perforated fire bridge 8 and port 9 into the working

page_text: cylinder m. After the completion of the outstroke by the working piston the
burnt products pass through the return port 10 through the valve 11 regenerator
and through exhaust valve r. One of a series of bars arranged as a grate is shown
at 12 which can be moved by a spindle 13 so as to throw away any ashes into the
one way cock 14 revolved by the plug 15. In this way it is made to reject the
ashes through the opening 16. An opening is shown at 17 which can be closed
by a screw plug. This opening 17 serves to admit a blast of air when lighting up
the fire.
Fig X shews a modification in which the regenerator illustrated in figs VIII
and IX is replaced by a tubular regenerator and the valves and 11 are
\dispensed with. The compressed air passes through the inside of the tubes and
after making the circuit described in figs VIII and IX passes outside the said tubes
and through the exhaust valve r. 28 shows a movable stopper which when
removed allows the fire place to be inspected and cleaned.
Fig XI is another modification of figs VIII and IX. In this liquid fuel is used.
Said liquid fuel is allowed to flow through tube 18, fed by a small pump supplying
fuel for each stroke, 19 pieces of asbestos, pumice stone or other refractory porous
material, to absorb the fluid and present a suitable surface for combustion. The
same form of regenerator is here shown as in figs VIII and IX but the position of
inlet and outlet valves is changed. The same figures are used to denote the valve
as in figs VIII and IX.
Fig XII shows a modification of figs VIII and IX for using a mixture of
combustible gas and air or combustible vapour and air. The said mixture passes
through the inlet valve j check valve k and tubes through the furnace 20 into
the working cylinder m by the port 9 and past the outside of the tubes of the
regenerator and thence past the exhaust valve. In fig IX is shown an apparatus
for charging the fuel into the furnace when solid fuel is used. The fuel is fed into
the hopper 21 whence it. falls in front of a pushing bar 22 by which it is pushed
into the cylinder in which the piston 23 works The fuel falls thence into the
horizontal cylinder in which the piston 24 works and is thence pushed forward by
the said piston 24 into the furnace 7. The said pistons 23 and 24 and the pushing
bar 22 are actuated by a bell crank 25 which in its turn is actuated by the
connecting rod 26 shown in dotted lines. The said connecting rod is actuated by a
crank on the disk 27 receiving motion from the silent ratchet gear 28. The said
silent ratchet is actuated by the eccentric 29, fixed on the countershaft E.
"
To avoid breakage the safety spring 30 is provided so as to allow the eccentric
to draw out without causing the silent ratchet gear 28 to revolve in the event of
any hard material getting into the apparatus or if the fuel gets jammed hard. The
proportions of combustible material and air are varied very considerably according
to the nature and quality of the fuel used. In all cases it is well to have the air
in good excess so as to secure perfect combustion and yet in not too great a
quantity such as will make combustion imperfect for want of sufficiently elevated
temperature and also reduce the efficiency of the working fluid. When ordinary
coal gas is used 8 to 12 volumes of air for each volume of gas are good working
proportions. With liquid fuel such as coal oil and petroleum 36 parts by weight
of air to one part by weight of fuel. For coal and coke 24 parts by weight of air
for each part by weight of coal or coke, and for dry wood or turf 1 part by weight
to 12 parts of air. The cubic capacity of the air compressor being known the
quantity of fuel needed per stroke may be readily ascertained.
Having now setforth the nature of my said invention and particularized the
same in such manner that others will be enabled to make and work my said
engines, I would have it understood that I do not confine myself to the precise
details herein described and shewn in the accompanying drawings, but what I
claim as of my invention is:―
In regenerative caloric engines in which gaseous, liquid, or solid fuel is used,
working substantially in the following order or sequence (A) Compressing atmo-

page_text: spheric air (B) Saturating such air with water vapour (C) Superheating the said
compressed saturated air in a regenerator and further superheating by combustion
and (D) Using the said compressed, saturated, superheated and burnt air to propel
a piston or its equivalent all substantially as setforth.
In Witness Whereof I the said James Hargreaves have hereunto set my hand
and seal this third day of February in the year of Our Lord one thousand
eight hundred and eighty three.
JAMES HARGREAVES (L.S.)