IMPROVEMENTS IN THE PRODUCTION AND IN THE APPLICATION OF HEATED AIR, AND IN THE MACHINERY OR APPARATUS EMPLOYED THEREIN
Year: 1874

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, Gentleman, for the Invention of
"IMPROVEMENTS IN THE PRODUCTION AND IN THE APPLICATION OF HEATED
AIR, AND IN THE MACHINERY OR APPARATUS EMPLOYED THEREIN."-A com-
munication from abroad by Joseph Hirsch, of Paris, in the Re-
public of France, Engineer.
Sealed the 9th April 1874, and dated the 17th February 1874.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 17th February 1874.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE PRODUCTION AND IN THE APPLICATION OF
HEATED AIR, AND IN THE MACHINERY OR APPARATUS EMPLOYED THEREIN," a com-
munication to me from abroad by Joseph Hirsch, of Paris, in the
Republic of France, Engineer, to be as follows:-
This Invention has for its object the utilization of the dignamic and
calorific properties of heated air, and consists essentially in effecting the

page_text: graduated combustion of liquid or gaseous fuel in a receptacle composed
of refractory material heated to a red heat, and containing air, the
temperature of which it is required to raise by the ignition of the liquid
or gaseous fuel injected therein, and in causing the heated air thus
produced to pass through a heat regenerator composed of small elements
of a refractory material presenting, under the form of small spaces, a
large contact surface and a considerable total section for the passage of
graduated combustion of liquid or gaseous fuel in a receptacle composed
of refractory material heated to a red heat, and containing air, the
temperature of which it is required to raise by the ignition of the liquid
or gaseous fuel injected therein, and in causing the heated air thus
produced to pass through a heat regenerator composed of small elements
of a refractory material presenting, under the form of small spaces, a
large contact surface and a considerable total section for the passage of
the fluid.
The Invention is applicable to motive power engines, to the generation
and accumulation of pressure, and to the production of hot blast.
In applying this Invention to motive power engines it is proposed to
employ two cylinders, one of which, termed the hot cylinder, is com-
posed of refractory material surrounded by a metallic casing, and has a
piston provided with a head, also composed of refractory material,
working therein, and the other cylinder termed the cold cylinder is
formed of metal, and has a metal piston working in it, the rods of both
pistons being connected to the same crank shaft.
The cold cylinder is maintained at a sufficiently low temperature by
means of cold water injected by a pump worked from the rod of the
cylinder or by a refrigerator or cold water jacket.
The two cylinders are placed in communication by means of the heat
regenerator, which contains a large number of thin strips or laminæ
composed of refractory material placed close together and superposed
and crossing each other, and so formed as to leave between them spaces
sufficient to admit of the free circulation of the fluid, or in lieu thereof
a screen of platinum wire or asbestos may be employed, or metal blades
may be used in the colder portion of the regenerator. The motion of
the two pistons is produced by means of the successive expansion and
contraction to which the air is subjected by its passage from one cylinder
to the other.
When the gases are ignited the air heated and expanded passes from
the hot cylinder to the cold cylinder, traversing in its passage the
regenerator to which it progressively imparts its heat, and in the motion
in the opposite direction the air returns through the regenerator,
gradually taking up its heat again, and re-enters the hot cylinder, when
an additional supply of combustible. gas or liquid fuel is subjected for

page_text: the purpose of restoring to the air by its ignition the quantity of heat
which has been expended. A valve or stopper is disposed in the passage
from the regenerator to the cold cylinder, by means of which the speed
of the engine may be varied by hand.
An air pump is provided driven from the crank shaft for the purpose
of supplying air from the atmosphere to compensate for the loss of air
consumed in the engine, but in some cases the pump may be dispensed
with, the cold cylinder obtaining the air direct from the atmosphere, by
which means the apparatus is greatly simplified.
The combustible gas or liquid fuel is supplied to the hot cylinder by
means of a pump which derives its motion through suitable arms and
connecting rods from the rod of the cold piston, the guide of one of such
connecting rods being made adjustable so as to enable the stroke of the
pump piston to be varied at pleasure. The pump also carries a clack
valve box, from which passes a pipe containing wire gauze, and conduct-
ing the gas or liquid fuel to the hot cylinder.
A pressure reservoir is provided beneath the cold cylinder with which
it is alternately placed in communication. This reservoir contains a
certain quantity of water, and the remainder of its capacity is filled
with air at a pressure corresponding to that at which the engine should
work, which pressure is regulated by means of a governor in combination
with a safety valve. The pipe leading from the cold cylinder is in
communication with a box containing a valve, which is operated by
suitable connecting rods from the rod of the cold cylinder, so that a
reciprocating motion is imparted to such valve corresponding to the
motion of the pistons, the effect of which is to cause the burnt air to
escape at each revolution of the crank shaft into the pressure reservoir,
whilst at the same time the refrigerating water is discharged from the
cylinder.
In order to prevent the communication of heat from the upper portion
of the hot cylinder to the lower portion, which it is desired to maintain
at a relatively low temperature, a water jacket is provided at that part,
the supply of water for which is derived in the first instance from a
reservoir above, and is maintained from the pressure reservoir by means
of the pressure contained in such reservoir.
When the Invention is applied to the generating and storing up of
pressure, the heated air is employed in a similar manner to that herein-
A 5)

page_text: before described, but its elastic force is utilized direct for the purpose of
compressing air in a reservoir, which air is magazined and may be
utilized as desired for the transmission of motive power to any required
distance or otherwise. In this modification a single cylinder is employed
in lieu of two cylinders, such cylinder baving a metal piston with a head
composed of refractory material working therein and being provided
with a hot and a cold chamber communicating together by means of the
regenerator. The piston is worked by a small engine, and a suitable
slide valve is provided for the purpose of regulating the inlet of cold
air into the apparatus and the egress of the air which is to be compressed
and stored up after the ignition has taken place in the hot chamber.
Any suitable number of these apparatus may be connected together
and combined with one reservoir, and the compressed air, after having
donc duty and partially expanded, may be directed by a return pipe into
a low pressure reservoir, from which the cylinder may draw its supply of
air in lieu of taking it direct from the atmosphere, by which a con-
tinuous circulation of the air is obtained. This arrangement may be
applied with slight modifications to blast engines for supporting com-
bustion in blast furnaces or for other purposes. In this case the waste
gases from the blast furnace are utilized in the apparatus, and the heated
air produced by the ignition of the gases is directed into the furnace, a
slide valve being provided for the purpose of opening and closing the
communication between the hot and cold chamber, as required.
The supply of the heated air to the furnace is also regulated by means
of a slide valve made hollow and packed with refractory material, and
both the valve and its box may be maintained sufficiently cool by a
circulation of cold water.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 29th July 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, send greeting.

page_text: of our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and succes-
sors, give and grant unto me, the said John Henry Johnson, Her special
license that I, the said John Henry Johnson, my executors, adminis-
trators, and assigns, or such others as I, the said John Henry Johnson,
my executors, administrators, or 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 IN THE PRODUCTION AND IN THE APPLICATION OF HEATED AIR AND
IN THE MACHINERY OR APPARATUS EMPLOYED THEREIN," a communication to
me from abroad by Joseph Hirsch, of Paris, in the Republic of France,
Engineer, upon the condition (amongst others) that I, the said John
Henry Johnson, my executors or administrators, by an instrument in
writing under my hand and seal, should particularly describe and ascer-
tain 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.
NOW KNOW YE, that I, the said John Henry Johnson, 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, reference being had to the accom-
panying Drawings and to the letters and figures marked thereon, that is
to say :-
The said Invention has for its object chiefly the utilization of the
dynamic and calorific properties of hot air.
The apparatus employed in carrying out this Invention are arranged
in the following manner:-They are composed of two cylinders, one of
which, designated the hot cylinder, is exposed to high temperatures, and
is constructed of refractory materials maintained within a metal envelope
or casing, within which cylinder works a piston having a head composed
of refractory material; the other cylinder, termed the cold cylinder, is
composed of metal, and within it works a metal piston. The two
cylinders are placed in communication by means of an apparatus termed
a heat regenerator, consisting of a receptacle lined with refactory

page_text: material so as to leave a chamber in the centre, which is traversed by
the gas in its passage from one cylinder to the other. This chamber
contains a large number of thin strips or lamina of refractory material,
which are arranged close together and in sets or tiers one above the
other crosswise so as to break joint, and also so as to leave between the
contiguous strips or laminæ of each set or tier spaces or intervals, the
total area of which is sufficient for the free circulation of the gaseous
fluid, to which such strips or laminæ offer a large amount of contact
surface within a small space or compass.
The regenerator represents by what may be termed a regular pro-
gression the very different temperatures of the two cylinders, that is to
say, the temperature of that portion of the series of strips or lamina
immediately adjacent to the hot cylinder is about equal to the tempe-
rature in such cylinder, and the temperature of the opposite extremity of
the regenerator is about equal to that of the cold cylinder, whilst
between these two extremities the temperature decreases from layer to
layer. If then it be assumed that the pistons have an ordinary recipro-
cating to-and-fro motion, and that in the hot chamber at the desired
period a suitable quantity of gas or combustible liquid susceptible of
being ignited on its introduction be injected the body of air enclosed in
the apparatus will be displaced and caused to pass from one cylinder to
the other, and vice versa, traversing the regenerator, in its passage
through which the air which has been highly heated and expanded in
the hot cylinder will gradually or progressively impart or deliver up its
heat to the regenerator, and will arrive in a cold condition in the cold
cylinder. In the reverse motion the air passes again through the
regenerator and becomes gradually reheated, and on its rearrival in the
hot chamber a further quantity of combustible gas is injected in order
to restore to the air the amount of heat which has been utilized for
mechanical or calorific purposes, as the case may be. On this principle
of the circulation of air in chambers, in which it is alternately cooled
and reheated, the apparatus herein-after described are based.
These apparatus consists of,-
First. A direct engine, that is to say, a motive-power engine, in which
the air heated and displaced in the manner herein-before mentioned is

page_text: transmit motive power to varying distances and to one or more receivers
simultaneously.
Third. A blast engine, in which the air acting in the manner herein-
before described is utilized as hot air, and blown direct by this engine
through a pipe or conduit into a blast furnace.
And in order that the said Invention may be fully understood, I shall
now proceed more particularly to describe the same, and for that
purpose
shall refer to the several Figures or the annexed Sheet of Drawings, the
same letters of reference indicating corresponding parts in all the corres-
ponding Figures.
Figure 1 of the Drawings represents a longitudinal section of a motive
power engine constructed according to this Invention; Figure 2 is a
side elevation of same; Figure 3 is an end view; and Figure 4,
a horizontal section taken along the line 1-2-3 (Figure 1). This
engine is composed of a cast-iron cylinder A forming more particularly
the base of the hot acting cylinder, which consists of an annular
body B of refractory material maintained by a sheet metal casing or
envelope B¹ outside. In the interior of this cylinder moves the piston C,
which is composed of cast iron, but is provided at its upper portion with
a block C¹ of refractory material. This piston is connected by a rod D
with the crank pin of a main shaft E, to which connecting rod there is
attached another rod F, the opposite extremity of which is connected to
a metal piston G working in another cylinder H which forms the cold
cylinder.
It will be observed that the communication is established between the
hot cylinder B and the cold cylinder H by means of an uninterrupted
passage, which is composed first of a passage a formed in the centre of a
body a of refractory material, which is immediately contiguous to and
in one with the body of the hot cylinder B, and is provided with an
external sheet metal casing a similar to the casing B' surrounding the
hot cylinder B. This upper passage a meets and terminates in the
regenerator, which is composed as before stated of a cylindrical body I
of refractory material surrounded by a metal casing I', and provided in
its interior with the series of strips or laminæ J of refractory material along
which the air passes in its course from one cylinder to the other. The re-
generator is supported on a base which constitutes a part of the cylinder H,
and which has formed in it a passage b, by means of which the interior

page_text: of the cylinder H is placed in direct communication with the lower part
of the regenerator. The communicating passage 6 is fitted with a
movable valve or closer 61 of a semi-cylindrical form, the diameter or
flat portion of which is in a line with the side of the passage b when
the passage is completely open, but is turned into the position shewn by
dotted lines in order to close such passage. This valve or closer admits
of the speed of the engine being diminished by simply moving with the
hand a handle 2 with which the axis of such valve or closer is provided.
The two cylinders are attached to a cast-iron frame or pedestal K, which
forms a support for them and for the driving shaft and other accessory
working parts.
The following are the most important accessory apparatus connected
with the engine, videlicet:-A fresh air-pump L situate at the side of the
cylinder A, the piston of which pump is attached to a connecting rod L'
which derives its motion from an intermediate centre or axis c actuated
by means of spur wheels d, d', from the main shaft E. This pump which
draws its supply direct from the atmosphere is provided for the purpose
of introducing pure air at every revolution of the engine to replace the
burnt air which is periodically expelled; this pump is for that purpose
placed in communication with the cylinder H by means of the pipe e
which opens into the lower passage b.
Another accessory consists of a smaller pump M Figures (2 and 3) for
the supply of the combustible gas. It has been before stated that the
heat in the engine is maintained by the injection of gas or combustible
liquid which becomes ignited as soon as it enters the hot part of the
apparatus. When combustible gas for example is employed it is
produced in an independent gas generator in which is effected the con-
version of solid fuel into gaseous fuel as herein-after described, or in
any other suitable manner. The object of the pump M is to inject the
gas into the upper part of the refractory cylinder B. The pump piston
is connected with a vertical rod M³, the lower extremity of which is
attached to an adjustable or sliding collar fitted on a lever arm 9 which
is carried on a shaft h, the opposite end of which is provided with a lever
arm i (Figure 1) connected by a rod with the joint pin of the cold
piston G. It results from this arrangement that the shaft / has imparted
to it a rocking motion which is converted into a reciprocating rectilineal
motion and transmitted to the connecting rod M¹ and thence to the
piston of the pump M, and by means of the adjustable or sliding collar f

page_text: which is susceptible of being moved along the lever arm 7, the stroke of
the piston may be modified at will for the purposes herein-after
explained. The body of the pump M is morcover provided with a valve
box M, in which terminates a pipe j leading from the gas generator,
which valve box is also fitted with a pipe j' communicating through the
ntervention of a junction piece filled with wire gauze diaphragms
with the upper part of the cylinder B.
A further important accessory is what is termed the pressure reservoir.
This apparatus consists of a closed chamber N formed underneath the
cold cylinder with which it is alternately placed in communication; this
chamber is partially filled with water, as shewn in Figure 1, whilst the
remaining space contains air which is maintained at a pressure propor-
tionate to that at which the engine is required to work. Communication
between the cylinder H and the upper part of the pressure reservoir is
established by means of a passage & which terminates outside in a box
O containing a stop or check valve, the rod O¹ of which surrounded by a
helical spring terminates in a knob against which acts a projection 0³
having a to-and-fro motion corresponding to that of the two pistons
C, G, imparted to it by means of a connection with the shaft h. It
results from this arrangement that as the stop or check valve is opened
and closed at every revolution of the engine at the same instant the
cscape of the burnt air from the cylinder H to the pressure reservoir is
effected. The refrigerating water which is constantly injected into the
cylinder H through a pipe having a rose head 7, as herein-after stated, is
also discharged at the same time from such cylinder. This water which
is introduced into the cylinder H for the purpose of cooling the air
which has a tendency to become heated in the cylinder is supplied by a
small pump P, the piston of which is actuated by a connecting rod P¹
attached to a lever arm P³ fast on the rocking shaft herein-before
referred to. The connecting rod P¹ carries the projection O² before
mentioned, which actuates the valve, placing the cylinder H alternately
in communication with the pressure reservoir N.
The engine operates in the following manner:-The temperature of
the portion of the apparatus which is required to be hot has to be suffi-
ciently elevated by introducing into the cylinder B through a special
inlet B, with which it is provided, first a current of hot air and then a
current of flame; the precaution being also taken to fill the pressure
reservoir. N with water up to the level of the opening of the escape

page_text: valve, which will be herein-after referred to. The gas generator being
now ready for effecting the supply, and the maximum stroke of the
piston of the gas pump M having been regulated, the crank shaft is
caused to perform one or two revolutions by turning the fly wheel E³,
and the engine is then started. The air which fills the engine, following
the motion of the two pistons, C and G, circulates from one cylinder to
the other, its temperature being greatly elevated by its passage through
the regenerator, and by the combustion of the gas introduced and its
volume, correspondingly augmented, and such temperature being alter-
nately lowered when by the combined motion of the pistons the air
passes from the hot cylinder to the cold cylinder H traversing the
regenerator and comes into contact with the water injected. During
these successive periods of the motion of the air, subjected alternately
to great variations of temperature, the variable degrees of pressure
exerted upon the crank pin produce at each revolution of the engine a
positive power which constitutes the utilizable mechanical power which
is transmitted to the driving shaft E.
As the air is not only heated and expanded, but a portion of it is
consumed at every revolution, the air pump herein-before described is
provided for the purpose of supplying fresh air to replace the burnt air,
the elements of which are at every instant expelled from the cold
cylinder through the passage k, as herein-before explained. These
burnt gases and the water introduced into the cold cylinder are con-
stantly stored up in the pressure reservior N. It is necessary that this
reservoir should be provided with an escape valve capable of maintaining
a uniform pressure within the reservoir, and also admitting of the degree
of pressure being fixed to suit the conditions under which it is desired to
regulate the working of the engine. In Figure 1 this reservoir is shewn
in communication by an aperture m with a box Q containing a valve n
opening outwards, which valve is maintained on its seat by a rod n¹
forced up by means of a spring n³, the tension of which may be regulated
by turning a nut n³. This arrangement admits of the valve opening
automatically when the internal pressure in the reservoir exceeds the
maximum assigned to it by the regulation of the spring n³. The gas and
water thus allowed to escape run off through the outlet aperture m¹, ;
which is fitted with a pipe m². To this valve also is applied the governor,
which admits of the speed of rotation of the engine being regulated by
reducing the pressure in the reservoir N if the speed increases, and by

page_text: allowing the pressure to rise when the speed is diminished. For this
purpose the regulating nut n³ is connected with one arm R (Figure 3)
of a bell-crank lever, the other arm of which is acted upon in one
direction by an opposing spring nt, and in the contrary direction by the
movable sleeve o of a governor R', such governor being actuated by
means of pulleys R², R³, from the driving shaft of the engine. It will
be seen that if the speed of rotation is accelerated, the sleeve o under
the action of the governor forces the bell-crank lever from right to left,
which has the effect of extending the lower spring n³, and thus relieving
the escape valve n.
When on the contrary the speed is diminished, the
sleeve o moves from left to right, and the bell-crank lever R being
forced back by the upper spring n' compresses the lower spring n³, so
that greater pressure will be exerted upon the valve n, tending to
maintain it upon its seat.
.
The cast-iron cylinder A is provided with a refrigerating jacket for
the purpose of preventing the transmission of heat from the hot portion B
of the cylinder to the portion A, which with the corresponding portion
of the piston has obviously to be maintained at a relatively low
temperature. This arrangement consists of an annular chamber A¹
which is formed in the cylinder A, and is open to the sides of the piston,
the joint being rendered tight by means of two elastic metal rings p,
arranged one at each side of the annular chamber. This chamber is
provided at one part of its circumference with a partition, at cach side
of which there is formed an aperture, the two apertures forming
respectively an inlet and an outlet for a current of cold water which
traverses the chamber, such water being obtained from the pressure
reservoir N, from which it is elevated by a pipe 9 by means of the
pressure existing in the reservoir. This water is however first introduced
by means of the elevating pipe 9 provided with a regulating cocks into
a receptacle S, whence it enters the annular chamber A' through a
pipe q', leaving such chamber by a pipe q which terminates in the
receptacle S. The pipe q³ shewn applied to that receptacle is intended
for the discharge of the liquid.
Figure 5 represents a horizontal section of the regenerator, shewing
one of the sets or tiers of strips or laminæ with which it is provided, and
Figure 6 shews in elevation and plan one of the strips or laminæ
detached. Each of the sets or tiers J, which are arranged the one above
the other, is composed of strips or laminæ of refractory material so

page_text: disposed as to provide the necessary spaces or intervals for the circulation
of the gases, but placed close together in such a manner as to be
equivalent to a single piece, as shewn in Figure 5.
It has been herein-before stated that cold water is introduced into the
cold cylinder H, for the purpose of absorbing the heat which would
result from the compression of the gas at a certain period of the stroke
of the corresponding piston. In lieu however of introducing cold water
into the cylinder, an apparatus termed a refrigerator may be interposed
between the regenerator and the cold cylinder. This apparatus is
composed of a series of metal tubes presenting a large surface or area
within a small space, and surrounded by cold water or cold air. The
cold cylinder may also be provided with a jacket for the circulation of
water.
In constructing the casings composed of refractory material any such
material fulfilling the required conditions may be employed. The strips
or laminæ may be formed of fire-clay, pipe-clay, compressed magnesia,
China-clay, or any other similar material; or they may be replaced by
screens composed of platinum wire or asbestos, and in the colder portion
of the regenerator plates, or wire of any suitable metal, either alone or in
combination with other materials, may be used in apparatus of large
dimensions. The space in the regenerator is divided into a number of
parallel compartments, in order to diminish the length of the strips or
laminæ, as shewn in Figures 8, 9, 10, and 11.
In the engine herein-before described the internal pressure is always
greater than the atmospheric pressure; engines in which this condition
is fulfilled the communicator of this Invention terms closed, and such
engines require an air pump for the supply of fresh air, as herein-before
stated. The engine may however be simplified by dispensing with the
pressure reservoir and the fresh-air pump, and placing the escape box O
in communication with the atmosphere, so that the cold cylinder H
may
draw in direct from the exterior, during a portion of the revolution
of the engine, the fresh air requisite for supporting combustion; engines
constructed upon this principle are termed open.
The regulation of the open engines, as also that of the closed engines,
may be effected by causing the governor to act either upon the length
of the rod O¹ of the escape valve, or upon the stroke of the pro-

page_text: In the open engines the injection of water and the means for refrigera-
tion may also be dispensed with.
One or more similar apparatus may be combined with those herein-
before described, either by means of beams or otherwise, so as to form
a double or multiple acting apparatus by the connection of two or more
single-acting engines suitably arranged.
The apparatus for generating pressure is illustrated in Figures 7, 8,
9, and 10 of the accompanying Drawings. Figure 7 is a general view
of a number of apparatus grouped or combined together, which appa-
ratus are constructed on the same principle as the engine herein-before
described, but are arranged for a different purpose. The object of this
arrangement is to utilize direct the dynamic properties of hot air for
the compression and storing up of air, such compressed air being sub-
sequently employed in the production of motive power, either in sub-
stitution for steam in existing engines, or for example in mines for
actuating the excavating tools for the distribution of motive power
throughout the whole extent of a town, and for other purposes.
The complete machine is composed (see Figure 7) of two or more
apparatus similar to that shewn in transverse section in the detail,
Figure 8, to which latter Figure reference is more particularly made
in the following description:-Figures 9 and 10 are respectively a
vertical and horizontal section of a portion of the regenerator, shewn
detached and drawn to an enlarged scale.
The apparatus, Figure 8, (which forms a constituent portion of the
complete machine,) consists of a cast-iron cylinder A surmounted by a
continuation B composed of refractory material which constitutes the
hot cylinder, and is constructed in a manner similar to that of the
direct engine herein-before described. In this cylinder A works the
metal piston C provided with a head C¹ composed of refractory material;
the upper part of the cylinder also communicates by means of the
passage a of refractory material with the regenerator J constructed
upon the principles herein-before described. In the present case
however the lower part of the regenerator is in direct communication
through the passage with the cast-iron cylinder A, which forms in
fact the cold cylinder, and is closed at its lower end by a metal
bottom E.

page_text: In the communicating passage there are formed two apertures c, d,
which are respectively susceptible of being placed in communication
with pipes G, H, termed respectively high and low pressure pipes,
against which apertures works a slide valve K, by means of which they
may be simultaneously closed or alternately opened, as required.
In order to facilitate the description of the action and mode of
operation of this apparatus let it be assumed that the low-pressure
pipe H is in communication with the atmosphere only, whilst the
high-pressure pipe G is in communication with the reservoir in which
the air compressed under the action of the apparatus is to be stored up.
The various portions of the apparatus being in the position shewn
in Figure 8, that is to say, the piston C₁ being at the top of its stroke,
and the two apertures c, d, completely closed or covered by the slide
valve K, the piston commences to descend (being drawn downwards
by mechanical means herein-after described); when it has performed
a certain portion of its stroke the slide valve K is moved so as to
uncover the aperture c. A suitable quantity of gas or combustible
liquid is introduced into the hot cylinder, such gas or liquid being
admitted at any desired period of the revolution as found most con-
venient), and the piston continues to descend. The air contained
within the apparatus being driven forward by the piston C flows
along the passage b, then passes through the regenerator and is dis-
tributed or expanded throughout the hot portion of the cylinder, but
as at the same time its temperature and volume are increased, and
the communication with the high-pressure reservoir is opened, the
increase in volume is utilized for effecting the storing up of air in
such reservoir, that is to say, during this period of the motion of
the piston a discharge under pressure of air contained in the apparatus
is effected through the pipe G; when the piston has nearly reached
the bottom of its stroke the slide valve moves back, and the two
apertures c, d, are again closed. The piston C again rises, and a
short time after it commences its upstroke the slide valve moving
from left to right uncovers or opens the aperture d, which has been
assumed to be in direct communication with the atmosphere. As the
piston continues to rise air is introduced to replace in the apparatus
that which has been conducted to the compressed air reservoir during
the preceding period of the motion, the air contained in the apparatus

page_text: is moreover at the same time caused to circulate from the hot to the
cold portion, passing through the regenerator in its traverse.
This apparatus is provided with some of the accessories similar to
those applied to the direct engine herein-before described, such for
example as means for effecting the circulation and introduction of cold
water, gas, or liquid fuel, and the like.
In Figure 7 to apparatus A, A, of similar construction to that herein-
before described, are shewn such apparatus, being connected by their
piston rods D with a beam F; a larger number of similar apparatus
may be connected together in any convenient manner. As acording to
this mode of applying the Invention the dynamic power of the hot air
is directly utilized for the compression of air in a special reservoir a
group or set of apparatus connected together in the manner described
should be actuated by an independent prime mover, which may be of
small power, simply sufficient to overcome the vis inertia of the various
movable parts; a steam engine may be employed, or by preference an
engine actuated by means of air compressed by the apparatus itself.
The air compressed by means of an apparatus arranged in this manner
is stored up in a reservoir L (Figure 7), from which the supply is taken
for different receivers situate at various distances, as for example the
receiver X, which is supplied through the pipe L'. The compressed air
after having operated in this receiver and been more or less expanded
therein has of necessity to escape on the return of the driving piston. This
escape of the air may be effected in two different manners, videlicet,-
First. The air may be conducted direct into the atmosphere. In this
case the compressing apparatus should be arranged in the manner
assumed, that is to say, with its aperture d in direct communication
with the atmosphere. Under these circumstances only a very low
pressure can be obtained in the interior of the apparatus A, B, and con-
sequently in the reservoir L, for which reason the following arrangement
is proposed.
Second. The air leaving the receiver X may escape through a pipe M¹
into another reservoir M, termed a low-pressure reservoir, which forms
the escape medium, and with which the pipe H leading through the
aperture d to the interior of the compressing apparatus should com-
municate. Under this second arrangement the result is equivalent to
that which would be produced if the surrounding atmosphere were at a
higher pressure, but as the final pressure obtained is greater the power

page_text: produced by a given apparatus is considerably in excess of that which is
obtained when the supply is drawn direct from the atmosphere. The
pipe M¹ forming a communication from the receiver or similar receivers X
to the low-pressure reservoir, and termed the return pipe, should be
employed in all cases in which the system of piping for the distribution
of motive power is extensive, the motive air thus circulating from the
generator to the high-pressure reservoir, from this reservoir to the
receivers, and from the receivers to the low-pressure reservoir, from
which the generator is to be supplied.
A combination of apparatus so arranged, that is to say, working at a
pressure independent of the surrounding atmosphere, forms a closed
machine according to the definition thereof herein-before given, and
requires the addition of a fresh air pump.
On the Drawing (Figures 7 and 8), various accessories are shewn,
such for example as regulating valves, water gauges, apparatus for the
circulation and injection of water, to which it will be unnecessary further
to refer, as they are either similar to well known apparatus or have been
previously described.
A pressure generator may be employed for the purpose of further com-
pressing air already compressed by means of a pump, or another pressure
generator so as to obtain higher pressures; there may thus be obtained
a type or arrangement of machines which the communicator of this
Invention designates double, triple, or multiple pressure generators.
Figure 11 shews the application of the Invention for the production
of hot blast. In constructing a blast engine upon the principles
enunciated the arrangement is somewhat similar to that of the pressure
generator herein-before described, that is to say, the complete machine
is composed, for example, of two or four similar apparatus A, B, con-
nected to mechanism common to the two, actuated by a motive-power
engine of small power, four apparatus being intended to operate collect-
ively as two double acting machines. The apparatus may be grouped or
combined together in any suitable manner, but the Drawing, Figure 11,
shews the arrangement of one constituent apparatus of the group or set.
The cold cylinder A is surmounted by the hot cylinder B as in the
pressure generator, and the metal piston C with its head C¹ of refractory
material is also employed, the two cylinders being connected by the
regenerator J and the cold passage b, as before explained.

page_text: At the upper part of the hot cylinder there is formed an aperture a,
which communicates through the intervention of a slide valve T (the
body of which is composed of refractory material), with a tube or passago
U also lined with refractory material, and provided for the purpose of
conducting the hot air impelled by the apparatus into the blast furnace.
This slide valve is formed of a hollow cast-iron box, in which cold water
admitted through its rods T is caused to circulate. The box T in which
the valve works is also maintained cool by a current of cold water.
The cold passage 6 has formed in it two apertures c, d, against the face
of which works a valve K, also perforated with an opening. The
apertures c, d, correspond respectively to two pipes G, H, the pipe G
being intended for the introduction of fresh air into the apparatus, and
that H for the escape of the burnt gases.
The upper part of the hot cylinder is provided with an aperture D
having a slide or other valve, to which aperture leads a pipe conducting
gas from the mouth of the blast furnace, such gas forming the com-
bustible which is to be introduced into the apparatus. When it is desired
to employ for this purpose the gases derived from a blast furnace such
gases may be drawn from the ordinary conduit by means of a pump or a
fan and forced through a liquid washing apparatus or other suitable
purifying apparatus, and under a low pressure into a gas holder com-
municating by means of a pipe provided with metal screens, a stop valve,
and a regulating valve with the hot chamber of the cylinder.
The apparatus operates in the following manner :-A short time after
the piston C has commenced its upstroke the slide valve K is brought
into the position shewn in Figure 11, that is to say, the aperture c is
uncovered. The atmospheric air enters the cold cylinder A, and the
slide valve K by reason of its form completely stops or closes the passage
6 so that the communication is intercepted between the cold cylinder
and the hot cylinder. The slide valve however at the same time uncovers
the aperture d, through which the burnt gases forced by the piston C, C¹,
and having traversed the regenerator may escape; and a suitable
quantity of combustible gas is simultaneously introduced through the
aperture D. During this period of the motion the slide valve T closes
the communication with the hot air tube or passage U. The piston
having arrived at the top of its stroke and commencing to descend the
slide valve K is moved and completely covers the apertures c, d, rc-
establishing the communication between the two portions of the cylinder.
B

page_text: After the lapse of a certain space of time the slide valve T falls and
places the tube or passage U in communication with the hot chamber of
the apparatus. The piston C, C¹, then continuing its descent the air
passes from the under to the upper side of the piston, becomes heated
and expanded, and is forced into the passage U leading to the tuyeres.
On the arrival of the piston at the end of its down stroke the slide
valve T is again raised into its closed position, and the piston recom-
mences its upstroke, and the same operations are repeated in
succession.
It is obvious that the partially burnt air which is discharged from the
apparatus constructed according to this Invention may be employed for
various purposes, as for example it may be used as a blast for an
apparatus for generating combustible gases, and in the case of "closed"
machines such air may be utilized for actuating some of the working
parts of the machines. The details of the apparatus generally may also
be variously modified, as for example slide and other valves capable of
working either automatically or mechanically at pleasure may be em-
ployed. The cylinder A. may be replaced by any suitable guide, and a
beam may be substituted for the direct acting connecting rod if
desired.
The gas generator which it is preferred to employ for the production
of the gascous fuel to be introduced into the apparatus is constructed in
the following manner:-This gas generator consists of a hollow shaft or
chimney composed of refractory material, the interior space of which is
of the form of a frustum of a cone arranged vertically with the larger
end below so as to facilitate the descent of the materials which are to be
introduced therein. The solid fuel is inserted as and in the proportion
in which it is consumed through the upper opening, which is closed
after each charge by a plug or stopper. The air is introduced at the
bottom, and traverses the column of fuel throughout its entire height,
delivering up its oxygen and becoming charged with combustible gases,
which escape through an opening formed near the top of the gas
generator.
The peculiar feature of this system of gas generator consists more
particularly in the mode of charging the generator, as herein-after
described. The fuel before being charged therein is mixed with a
certain quantity of crushed or pounded fragments or waste of bricks
composed of refractory material, the advantages of which will be

page_text: apparent from the following considerations, taking coal for example as
the fuel employed :-
If air be caused to pass through a column of ignited coal of a suitable
height as soon as the operation has fairly commenced the oxygen of the
air becomes converted first into carbonic acid and then into carbonic
oxide, which passes away, conducting with it the products from the
distillation of the coal. The gases thus produced escape whilst still in a
very hot condition, and they, together with the ashes and cinders, absorb
a considerable amount of heat which is in that case not susceptible of
utilization.
By the improved process however the fragments of refractory
material collect or receive at the upper part of the apparatus the excess
of heat which is contained in the gases. The fragments thus become
heated, and as they descend their temperature is constantly increased in
proportion until they pass the portion of the cone in which the chemical
reactions take place. Below this point, the coal having been com-
pletely consumed, the fragments are mixed with ashes only and they
are traversed by the ascending current of air which takes up the heat
they retain. The air when it arrives in contact with the fuel is thus in
a highly heated state and consequently in the most suitable condition to
ensure the chemical reactions being completely carried out. This
arrangement moreover admits of the admixture with the air introduced
of considerable quantities of water or carbonic acid, so as to obtain gases
richer in combustible elements and less diluted with nitrogen as they
leave the gas generator, by which means the fuel employed is more
completely utilized. A portion of the mixture of the fragments of
refractory material and ashes which has become cold is removed at
intervals through an aperture formed below before inserting a fresh
charge from above.
During the normal operation of the appartus the descending column
of fuel mixed with the fragments of refractory material is cold at the
upper portion of the apparatus, and at a high temperature at the medium
point at which the re-actions are produced, and at the lower part of the
apparatus there are collected cold ashes and also fragments of refractory
material in a cold condition, which may be withdrawn and re-utilized.
The gaseous column which is cold at the bottom portion of the
apparatus becomes gradually heated, the air arrives at a high temperature

page_text: in contact with the fuel and the gases produced become sufficiently
cooled down and leave the apparatus in a cold condition.
The following advantages are obtained by means of this arrangement,
videlicet: The heat is much better utilized, the fuel is more completely
consumed, the ashes not retaining any combustible particles, the chemical
re-actions are effected under the most favorable conditions, the gases
are rendered richer, and the mass of fuel is exceedingly permeable.
Any known means of constructing the apparatus and for performing
the operations of charging, blowing, and washing may also be employed.
The gas generator may also be surrounded with a metal casing in
order to produce the gas therein under pressure so as to wholly or
partially dispense with the gas pump herein-before referred to in con-
nection with the improved hot air apparatus.
There may also be introduced into the gas generator with the current
of air either water in the form of a vapour or liquid or partially burnt
air if found desirable.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that what I consider to
be novel and original, and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is,―
First. The production of heated air and its utilization for obtaining
motive power, hot blast, and for other heating purposes, by causing air
to pass through a highly heated regenerator composed of refractory
material encased in metal in which its temperature is gradually raised
into a hot chamber also composed of refractory material encased in
metal in which its temperature is further elevated by the ignition and
gradual combustion of gaseous or liquid fuel introduced into such
chamber, the whole arranged and operating substantially in the manner
herein-before described and illustrated by the Drawings.
Second. Forming the regenerator of ranges or tiers composed of strips
or laminæ of refractory material, or their equivalent, arranged so as to
leave small intervening spaces containing a large total area in transverse
section for the passage of the air, and a large amount of contact surface
within a small compass, the whole being surrounded by refractory
material encased in metal, substantially as herein-before described and
illustrated by the Drawings.

page_text: ΥΠΗ
"PP
illustrated by the Drawings.
nonno
TA
CULL
ΔΙΑΤΟΝ ΠΙΟ ΤΟΤΤ
nu
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and seal, the Twenty-eighth day
of July One thousand eight hundred and seventy-four.