IMPROVEMENTS IN STEAM GENERATORS AND ENGINES
Year: 1871

page_text: LETTERS PATENT to James Dodge, of Eccles, in the County of
Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN STEAM
GENERATORS AND ENGINES."
Sealed the 18th May 1872, and dated the 21st November 1871.
PROVISIONAL SPECIFICATION left by the said James Dodge at the
Office of the Commissioners of Patents, with his Petition, on the
21st November 1871.
I, JAMES DODGE, of Eccles, in the County of Lancaster, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN STEAM GENERATORS AND ENGINES," to be as follows:-
My Invention consists, firstly, in an improved arrangement of
generator, whereby I more fully utilize the heat arising from the com-
bustion of the fuel. To accomplish this I use a generator of considerable
vertical dimension, and place the fire-box at the upper end thereof
a short distance below the water line. Air passes freely or is forced
into this fire-box, and the hot gases arising from the combustion of the

page_text: fuel are caused to pass into or through the chamber containing the steam
which is situate in a separate compartment, and it thus becomes highly
superheated. The vapours having been used in an engine which I at
present assume to be of any ordinary construction, are conducted by any
suitable pipe or pipes to the upper part of the generator, and are passed
downward therein, by which means the greater part of the heat is
extracted by the water, after which they escape to the atmosphere, or
are applied to heat the air which is admitted to the furnace.
My arrangement of steam engine is designed especially for use in
conjunction with my improved generator, or in other cases where vapours
of very high temperature are employed, and consists in arranging the
valves and cylinders so that one side thereof is submitted to the cooling
action of water.
The arrangement I propose is a fixed cylinder filled with water,
and at the bottom of which is a valve or valves answering to the
ordinary slide valves. This part may be called a stationary piston, and
on the outside thereof is a cylinder fitting that first mentioned, and
into which the heated vapour is admitted and allowed to pass out by
suitable ordinary valves. The stroke in the other direction is obtained
by similar apparatus. I have above stated that the heated vapours from
my improved generator may be used in any ordinary engine, in such
cases however I prefer to pass the pipe or pipes which contain the
products of combustion through the steam chamber, and from thence
downward through the water in the generator, the steam only being
used for the engine. In this case as before the exhaust steam will pass
through the generator.
In some cases I propose to use any of the ordinary volatile oil for
fuel, the generator being substantially the same, but I propose to force
heated air through the said oil to cause vapours to be evolved, which may
be ignited and used for evaporation or for exerting expansive force.
In cases of small generators and engines I propose to place the oil in
a stationary cylinder, and to adapt thereto sliding cylinders, and to
ignite the vapour at each stroke.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Dodge in the Great Seal Patent Office on
the 21st May 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
DODGE, of Eccles, in the County of Lancaster, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of November, in the
year of our Lord One thousand eight hundred and seventy-one, in
the thirty-fifth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said James Dodge, Her
special license that I, the said James Dodge, my executors, adminis-
trators, or assigns, or such others as I, the said James Dodge, 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 IN STEAM GENERATORS AND ENGINES," upon the condition,
amongst others, that I, the said James Dodge, 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 James Dodge, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement and accompanying Drawings, that is to say :-
My Invention consists, firstly, in an improved arrangement of
generator, whereby I more fully utilize the heat arising from the com-
bustion of the fuel; and, secondly, in an improved form of engine to
be used for vapours of high temperature.
The first part of my Invention is shewn in the accompanying
Drawings. At Figs. 1 and 2, the former of which represents the same

page_text: in vertical section, and the latter in horizontal section taken about the
line A, B. That which may be called the outward shell of the boiler is
shewn at 1, projecting into which is a chamber 2 constituting the fire-
place, and situate according to my Invention in the upper part of the
boiler. At 3 are the fire-bars, the inward ends of which are formed
with sockets resting upon a projecting part 4, on which they can turn
as a centre. The front ends of the bars rest agains a plate 5 consti-
tuting the front of the ash-pit, which is capable of removal at pleasure.
At 6 is a hopper having an opening at top closed by a sealed lid 7, and
at 8 is an aperture closed by a lid which is kept in its place by a
weighted lever 9. Above the fire-place is a series of tubes 10 opening
into a chamber 11; and leading from the said chamber is another series
of tubes 12 extending downward and opening at their lower ends into a
chamber 13, in which there are horizontal tubes 14 passing through the
said chamber, and opening at one end into a passage 15 which is in
communication with a pipe 16 extending upwards, and being at top open
to the ash-pit 17. The other ends of the tubes 14 are open to a
passage 18, and at 19 is a flue leading to the chimney. The tiers of
tubes 14 are divided by plates 20, 20*, which alternately reach the ends
of the chamber 13, and leave spaces to be hereafter referred to. At 21
is a close chamber extending across the boiler and situate in the water
space thereof, having a number of tubes 22, which extend through the
said chamber 21, and are open at both ends. Through these tubes
therefore the water may circulate. At 23 is a pipe opening into the
chamber 21, and connected at its other end by any convenient arrange-
ment with the exhaust steam of the engine; and at 24 is another pipe
open to the chamber 21 for conveying away water of condensation and
any uncondensed steam. At 25 is the steam pipe situate within the
chamber 11, which it traverses several times, as seen in the plan view,
Fig. 2, finally passing to the engine by the pipe 25*. At 26 is the feed
pipe for the boiler.
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Sallawa
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page_text: arrive in the chamber 13, but are prevented from passing direct to the
flue 19 by the plate 20, and by which they are guided, as shewn by the
arrows, so as to pass over the right hand end of the said plate, and on to
the second plate 20*, by which in like manner they are conducted to
the left-hand end of the chamber again to return, and finally to escape
by the flue 19. This passage of the gasses in the chamber 13 has
imparted heat to the tubes 14, and there is consequently established a
draft through the opening 18; and the air passing through the said
tubes 14 becomes heated and ascends as a hot blast up the pipe 16 to
feed the fuel in the fire-box 2.
Instead of allowing the air to pass through the opening 18 by a
natural draft the said opening may be connected to a fan or other
blowing apparatus. At 27 is a bonnet situate over the pipe 16 to
disperse the air, and to prevent ashes from falling therein. The
exhaust steam from the engine passes through the pipe 23 into the
chamber 21, through which it passes in contact with the tubes 22, and
is then carried away by the pipe 24 having been robbed of its heat or
partially so, for as least to any considerable extent cannot be transmitted
downward the exhaust steam will pass through comparatively cool
water; and I may here observe that it is owing to this property of heat
not passing downward that I am enabled to highly superheat the steam
by the products of combustion, but as steam cannot be superheated on
itself or on the liquid from which it is evolved I place a valve 25** on
the bottom of the pipe 25, which opens upwards as the steam is drawn
off for the engine.

page_text: It will be observed by inspecting Fig. 2 that the tubes 10 do not
extend across the whole width of the boiler, and this allows space for the
introduction of the steam pipe 25.
In reference to the pipes 10 I so arrange them that the products of
combustion shall be reduced to about 600° F. of heat before they reach
the chamber 11.
My improved engine is designed for use with highly heated vapours.
and is shewn in section at Fig. 3. At 30 is the side of the generator, or
it may be of any suitable chamber communicating therewith, the water
line being say at 31. At 32 are orifices establishing a communication
between the water and a cylinder 33, which being bolted to the plate 34
is stationary, and is by the above-mentioned means kept full of water,
on the outside of this is another cylinder 35, which for a portion of its
length bears upon the fixed cylinder 33, and is packed to the surface
thereof by means of rings 36 of any ordinary construction. To the
cylinder 35 is jointed a connecting rod 37, the other end of which is
coupled to a crank pin 38, extending from the driving shaft 39, the rod
37 being forked so as to take both sides of the cylinder. At 39* is a
pipe or one of a series, the upper end or ends being open to the
steam chamber. This pipe or pipes extend through the plate 30 and
traverse the stationary cylinder 33 communicating with a passage 41,
situate beneath a slide valve 42, capable of opening and closing induction
and eduction ports 43, 44. The valve rod is shewn at 45, jointed to a
lever 46, mounted on a shaft 47, which is caused to vibrate by an
excentric, tappet, or by other ordinary apparatus mounted on the driving
shaft 39. According to the positions of the parts shewn the steam is
passing along the pipe or pipes 39* to the passage 41, from whence it
passes along the port 43 to the space 48, and there exerting its expansive
force against the end 35* of the moveable cylinder forces it forward, and
by means of the rod 37 communicates motion to the driving shaft 39,
upon which it will of course be understood there is the usual fly wheel.
When the cylinder 35 has completed its stroke the eccentric or cam
on the shaft 39 will have shifted the valve 42, so as to close the
induction port 43, and open the eduction port 44, through which the
steam in the cylinder 35 passes, and from thence along the passage 44*
to the atmosphere or condenser, after which the cylinder 35 passes
back to the position shewn, and the valve 42 again opens the induction
port.

page_text: By the above description it will be seen that the arrangement refers
to a single-acting engine; if it be required to make it double-acting it
will simply be necessary to employ another fixed and stationary cylinder
coupled on to the shaft. It will also be seen that as the cylinder 35 is
filled with water the working parts 36, 42, are kept comparatively cool, the
temperature of the said water being lower than that of the superheated
elastic fluid employed. Figs. 4, 5, 6, represent in longitudinal, transverse,
and horizontal sections a modification of the engine above described.
At 50 is the fixed cylinder before mentioned, but in this instance
it is formed with an enlarged part 50*, the closed end 51 of which is
provided with an orifice through which a tube 52 extends, passing into a
stuffing box 53. Within the said stuffing box is also another tube 54,
secured to the end 51 by lugs and screws, one of which is shewn at 55,
and closed air-tight at its end by a cap 56 capable of being forced
forward by a cross bar and screw 57. The upper part of the tube 54
has an orifice which communicates with a hopper 58, provided
at its upper end with an air-tight cover 59, pressed downward by a
screw 60. Within the fixed cylinder 50, 50*, and forming part of the
tube 52, is a chamber 61, having at one end a number of perforations
62, corresponding to other perforations 63, formed in the end of the fixed
cylinder 50, and communicating therefore with the interior of the
moveable cylinder 64, which at this end is situate within a second fixed
cylinder 65 provided with a valve 66 which opens inward. To the end
65* of the cylinder 65 is a pipe 65**, which passes downward and is
open at its lower end to a chamber 66, the said opening having a valve
67 which opens inward to the chamber 66. On either side of the
chamber 66 are other separate chamber 68 in which are situate a
number of tubes 69 open at both ends, and communicating at one end
with a passage 70, provided with a pipe 71 which communicates at its
other end with the valve 72, and constitutes at its other end an eduction
port 73, which valve is actuated from the main shaft 74, as in the former
instance. At 75 is a pipe passing through the end 63 of the fixed
cylinder 50 and forming an induction port 76 for the valve 72, the said
port being continued as at 77 so as to communicate with the chamber
66.
At 78 are pipes which supply water or other cooling liquid to the
two chambers 68, and which therefore surrounds the tubes 69, the said
water being supplied by pumping or by other source of pressure, and
from these chambers 69 it is transferred to the space 80 which

page_text: surrounds the axed cylinder oʊ, as in the former instance, such trans-
ference being effected by any suitable communication between the two
parts 68, 80.
Having described the arrangement of the engine I will now proceed to
point out its operation:-Coke or other suitable fuel in an ignited
state is placed in the hopper 58 by opening the lid 59, and so as to fill or
partly fill the chamber 61, and the lid 59 is replaced and made air-tight,
and I will now assume (the reason will hereafter be seen) that the
chamber 66 has been supplied with compressed air. This air having
been forced through the port 76 and along the pipe 75 has entered the
space 63*, and from thence has passed through the perforations 63, 62,
into the chamber 61, and through the ignited fuel therein, by which
means it has become highly heated, and consequently has attained
considerable expansive force which is now exerted against the end of the
moveable cylinder. This cylinder is therefore driven in the direction of
the arrow, and immediately the valve 72 is shifted so as to close the
port 76, and a further motion of the cylinder 64 drives the air which has
passed through the valve 66, along the pipe 65**, through the valve 67
and into the chamber 66, compressing it therein to obtain the condition
mentioned as above assumed. The cylinder 64 now continuing to travel,
the valve 72 will be shifted so as to bring its cavity beneath the two
ports 73, 76, this movement taking place when the stroke is nearly
accomplished, and when therefore the moveable cylinder returns in the
contrary direction to that of the arrow the heated vapour will be
expelled through the said ports along the pipe 71 and into the passage
70, from whence it passes along the two sets of pipes 69, and escapes at
the other end to any suitable flue. As the vapour passes through these
tubes, which are surrounded by water or other cooling liquid, it of course
gives off its heat, which being taken up by the said water is transferred
to the space 80 by the means above mentioned and by its own gravity,
and thus the operation continues.
This arrangement is as before single acting, but may be made double
acting as already mentioned. The water in the space 80 of course
becomes highly heated, and steam will be generated; at 81 is a dome
for receiving this steam, and from thence it may be conducted to an
engine of the above-described construction or to one of ordinary
arrangement. In case any of the volatile oils are used for the above