Improvements in the Method of Burning Fuel to Obtain Complete and Smokeless Combustion, and in the Furnaces Used therefor.
Year: 1894

page_text: Date of Application, 3rd July, 1894-Accepted, 22nd Sept., 1894
Improvements in the Method of Burning Fuel to Obtain Complete
and Smokeless Combustion, and in the Furnaces Used therefor.
A communication from abroad by MEYLERT MELVILLE ARMSTRONG, of
3609, Hamilton Street, in the City and County of Philadelphia, State of
Pennsylvania, United States of America; Manufacturer.
I, JOHN CORRY FELL, of the Firm of Fell and Wilding, of 1 Queen Victoria
Street, in the City of London, Chartered Patent Agent, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
This invention relates to the combustion of fuel for the more complete develop-
ment of caloric by converting the fuel into combustible gases by the aid of air or
air and steam and embraces the method or process and also the apparatus as
applied to the generation of steam and has for its object the thorough conversion
of the fuel into combustible gases, whereby hydrocarbons or other volatilizable
portions of the fuel are prevented from becoming afterwards condensed in the form
of smoke or soot, but assume a gaseous character susceptible of clean combustion,
and are completely utilized with the other combustible portions of the fuel.
Briefly stated the process or method may be said to consist in first igniting a
charge of fuel in a furnace chamber or retort of considerable length and permitting
it to burn by natural draft until the combustion of the entire fuel column has
commenced, the products of combustion during this stage of the operation being
permitted to escape after which the vessel is closed, and currents of air more or
less heated are passed transversely through perforations in the retort or furnace,
and the fuel column as it is consumed and progresses through the furnace or
retort, and further on in the length of the retort returning the gaseous products
with additional air or air and steam transversely through the portion of the fuel
in the retort or vessel which has previously been treated, and partly consumed,
and repeating this operation or process of returning the products of combustion
with air, or air and steam any desired number of times, so that the hydrocarbons
and other combustible portions of the fuel become converted into combustible
gas which does not precipitate carbon, and is thus consumed with complete exhaustion
and good economy of the combustible.
As the fuel column in the retort is consumed and subsides additional fuel is added
from time to time which ignites from that already in the retort and also from the
heat of the retort, so that the operation is continuously maintained, and a
continuous supply of fuel gas susceptible of smokeless combustion is discharged.
The apparatus for applying this process to the generation of steam and which
forms a feature in this invention operates by circulating water through part of the
fuel chamber to preserve such chamber from impairment by heat and at the same
time to augment the steam generation capacity of the whole apparatus.
The accompanying drawing represents several forms of apparatus adapted to
conduct this process.
Figure 1 is a vertical section of one form in which the air and products of fuel
combustion repass six times through the fuel.
Figure 2 a vertical section in which they return once and pass twice across
and through the fuel, in both these instances being in a vertical chamber or
retort.

page_text: Figure 3 shows an inclined retort in which a like process is conducted.
Figure 4 shows a vertical retort in which the fuel is fed in at the bottom and
forced upwardly, and the gas and products of combustion return twice through
the fuel.
Figure 5 shows a cross section of a preferable form of retort for this purpose.
Figure 6 shows a horizontal section of a furnace in which fuel is fed horizontally
in the direction of the length of the furnace and air, or air and steam, transversely
through it.
Figure 7 a cylindric vertical retort or furnace with annular air supplying and gas
conducting chambers surrounding it.
Figure 8 shows an annular retort with both a central and an annular series of air
supplying and gas conducting chambers.
Figure 9 shows a horizontal section of the furnace depicted in Figure 7, made in
the plane indicated by the dotted line,, in Figure 7.
Figure 10 shows a horizontal section made in the plane indicated in the dotted
line z, z, in Figure 8.
Figure 11 shows in vertical section an apparatus embodying this invention applied
to an internally fired steam boiler to and from which water and steam are circulated
through tubes forming the sides of the fuel chamber.
Figure 12 shows in section a modified application of the invention to an externally
fired horizontal flue boiler.
Figure 13 shows in vertical section a modified application of the invention to an
internally fired marine boiler.
Figure 14 shows in vertical section a modification of the apparatus shown in
Figure 13.
Figure 15 shows in vertical section an apparatus in another form applied to a
tubulous steam boiler and
Figure 16 shows a front view of different constructions of the perforated fuel
chamber.
Fig. 17 is an enlarged section of furnace from Fig. 11 and
Fig. 18 is a plan of rocking segment bars of same.
Referring to Figures 1 and 2, the fuel is supplied in the retort 1, and the fire
kindled in the ordinary method as in a stove upon a grate 2, and supplies the fuel
until about two thirds full more or less, the combustion being by natural draft, and
the products of combustion during this kindling operation being allowed to waste,
and when the fuel is fully ignited, and the retort 1, and magazine 1' above it filled
with fuel and closed so as to stop the further waste of the products of combustion
the normal operation commences as follows:-
:-
A current of air is passed transversely across the upper part of the retort through
the perforated walls 6 thereof, and entering a chamber 3, returns from said chamber
through the fuel and retort to the chamber 4, and thence to another chamber,
passing and repassing across and through the fuel, in the meantime fuel is con-
tinuously supplied at the top of the retort, and as it is exhausted it sinks, and
becomes heated to incandescence and comes in contact with the products of
combustion of the former combustions, and air preferably in heated condition,
which is admitted in the several chambers 3 and 4 either alone or together with steam,
so as to augment the amount of oxygen supplied and increase the liberation or
generation of gas. The gas, after finally passing through the fuel as the fuel
becomes exhausted at the grate, may be immediately ignited for use, or may be
collected, washed, purified and stored for the purpose of distribution and later
consumption.
The distance between the points of discharge of gas and products of combustion
from the retort 1 to the point of re-entering the retort from the chanuel or
chamber 3, should be such relatively to the diameter of the retort that the gases
and air or air and steam shall find an easier exit to the next chamber 3, on the
opposite side of the retort from the point of re-entrance than by flowing lengthwise
through the column of fuel in the retort 1.

page_text: Referring to Figure 3 the retort 1, is placed in an inclined or oblique position,
and the fuel fed obliquely downwardly through it. In this retort the fuel is ignited in
the same manner as in that described in the previous figures and is similarly fed, the
fuel becoming heated to incandescence in its descent as it is exhausted or consumed.
Air entering transversely near the upper end, passes through the perforations in the
walls 6, and passes across the retort; thence to the chamber 5, where the further
supply of air is mingled with it and again passes transversely through the retort,
and through a part of the charge which has already been subjected to the first air
supply to which it combines and is withdrawn below the retort is combustible gas,
whence it is used by being withdrawn for calorific purposes under boilers, and
furnace or other apparatus requiring heat.
In the form shown in Figure 4, the retort 1 is vertical; fuel however, is fed in
the base and forced upwardly, and the primary air current enters the retort near
the base, and rises in the retort and passes transversely across the retort, returning
again with an increased supply of air, and so on, passing and repassing, until the
top of the retort is reached.
Obstructions 7, 7, as indicated in dotted lines, may be placed in the retort so as
to compel the products of combustion to traverse transversely rather than vertically
in the retort; but by judicious proportioning of the form of the. retort this may
become unnecessary. In this retort the fuel is ignited by kindling from the
bottom, and the top is left open until the fuel is fully ignited to incandescence after
which it is closed and the normal operation of feeding from below proceeds.
A preferred form of retort is shown in cross section in Figure 5.
Figure 6 shows yet another form of retort marked 8 in which the fuel is ignited
as in an ordinary furnace and then filled and thereafter is forcibly fed lengthwise,
say from the right to the left, and as it is consumed heats to incandescence in its
progress and the air current passes transversely through it in a horizontal direction,
receiving an augmentation of air, or air and steam from the returning channels or
chambers 3 at each time when it returns into the retort, so that the air and the
free gases resulting from the combination of air and decomposed steam are
thoroughly charged with carbon and rendered combustible in the highest practicable
degree.
.
The gas thus generated passes through a final contact of the incandescent
fuel and has a high heating value. If burned immediately it utilizes the heat
developed in its generation, and when stored is adapted to the purposes of gas
engine propulsion, metallurgical furnaces, steam generation, and in short to any of
the uses to which gaseous fuel may be applied, and with proper burners may be
used for culinary and illuminating purposes.
Referring to Figures 7 and 9, the fuel is ignited as in the case of the retort shown
in Figure 1, and is continuously fed in the top of the cylindric retort 10, and as it
is consumed heats to incandescence and air introduced through perforations 6, in
the retort 10, and gas passed from the retort 10, into the annular chamber 11,
where it mingles with additional supplies of air or air and steam, and re-enters
repeatedly and passes transversely through fuel in the retort for further combina-
tion therewith at points further from the inlet and the resultant gases are
discharged through the flue 12.
Referring to Figures 8 and 10, fuel is ignited and fed as in Figures 1, 7 and 9, in
the top of a perforated retort 13, but the retort differs in being of annular form
and the products of combustion and additional air, or air and steam pass and
repass through it to and from central chambers 14, and annular surrounding
chambers 15, and is finally discharged for use at the flue 16, and in the same
manner and with like effect as in the preceding figures.
Referring to Figure 11 and enlarged details thereof in Figs. 17 and 18 the fuel
chamber 1, is formed of two series of curved tubular grate bars 17 and 17' with
intervening air spaces between the tubes.
The tubes 17 and 17' are connected at their upper and lower ends by tubes 18
and 19 with the water space of the boiler 20 so that a constant circulation of water

page_text: is maintained through them and any steam generated in them is discharged into
the boiler 20.
Between the front portion of the tubes 17' is placed a raking attachment 21
consisting of segments 22 supported on rock shafts 23 which are connected by
link 24 to a lever 25 by which they may be vibrated and the fuel progressively
moved toward the more steeply inclined part of the chamber 1, which it fills, a
chamber 26 is formed under this point of the grate into which air enters by the.
door 27, and partly burns the fuel, a grate 29, which may be of any of the usual
constructions receives any fuel which may fall between the tubes 17 and they are
burned by air admitted to the ash pit or chamber 39 below through the door 28.
A partition wall 31 encloses a space or chamber 32 between it and the bent part
of the tubes 17' a chamber 33 is enclosed at the upper part by a water wall or
curtain 34, and the lower part by a wall 35, to which access is had by a door 36
opening into the chamber 39 for purposes of cleaning and inspection.
Air enters the chamber 26 passes upward between the tubes 17' through the fuel
in the grate into the chamber 1 partly burning the fuel, thence the products of
this partial combustion pass between the upper portion of the tubes 17 and return
through the fuel in a state of incandescence in the chamber 1 included between the
bowed or bent portions of the tubes 17 and 17' into the chamber 32, thence again
through the incandescent fuel in the chamber 1, at the lower part into the
chamber 33 whence they pass with thorough combustion through the flues 37
of the boiler 20.
Above the door 36 in the chamber 39 is placed a toothed or grated cylinder 38
which closes the bottom of the retort, or fuel chamber 1, by rotating which the
cinders and clinkers of the fuel are disintegrated and discharged into the ash pit 39
the repeated passage of the products of combustion and air, through the fuel
converts it into combustible gas which burns smokelessly with great heating effect.
Referring to Figure 12 the fuel chamber 1, is formed with an inclined bottom or
grate 171 formed of water tubes connected by pipes 18 and 19 with the water space
of the boiler 20, a partition wall 31 divides the ash pit 39 from the gas and
combustion chamber 33, a raking attachment 21, similar to that described in
Figure 11, is placed between the tubes 17' front of the partition wall 31, and serves
to progress the fuel from the front to the rear of the grate 17', a grate 29 is
located below the raking attachment 21 as in the preceding figure; a door 36
affords access to the chamber 33 from the ash pit 39 for the purposes of cleaning
and inspection.
The fuel is supplied on the front part of the grate in the chamber 1 and ignited
with kindlings in the usual manner as it becomes heated to incandescence it is
pushed backward until the rear portion of the water grate 17' over the chamber 33
is fully covered with incandescent fuel and new fuel supplied at the front which
ignites and passes the vapors, and products of combustion downward through the
incandescent fuel into the chamber 33 whence they pass in gaseous form in a state
of smokeless combustion under the boiler 20, and return through the flues 37,
imparting heat to the water and generating steam.
In the form of apparatus shown in Figure 13 a fuel hopper or magazine 40 is
applied to the front of the furnace of a boiler 20 and the fuel is fed continuously
to the water tube grate 17, (wbich in this case is inclined), and is prevented from
rolling off the front and more steeply inclined part of the grate over the chamber 33
by the grate 17 of water tubes.
The water tube grates 17 and 171 are connected with the water spaces of the
boiler 20, by the pipes 18 and 19; The air passes upwardly through the fresh fuel
at the front of the fuel chamber thence with the products of such partial com-
bustion over and down through the fuel between the water grates 17 and 17' into
the chamber 33 and thence in gaseous form in smokeless combustion, in the direction
indicated by the arrows through the flues 37 of the boiler 20 heating the water and
generating steam.
In the form of apparatus shown in Figure 14, the, portion 41 of the fuel

page_text: chamber 1 containing incandescent fuel is perpendicular instead of inclined in
operation it is the same as that shown in the preceding figure.
It is essential for the success of this process, that the fuel in the chamber shall.
be so arranged that the products of the first combustion must pass again through
the incandescent fuel and a failure to fill the chamber 1, at the portion over the
chamber 33, will defeat the operation, by practising this precaution, the operation
of the furnace with smoke'ess combustion can proceed continuously so long as fuel.
is supplied.
In the form shown in Figure 15, the fuel chamber 1, is formed of two series of
parallel vertical water tubes 17 and 171 connected with the water space of the
boiler 20 by pipes 18 and 19 so as to circulate water through the tubes 2 and from
the boiler, a fuel magazine 40 is placed above the fuel chamber 1, so as to keep it
constantly supplied. A grate 29 receives any fuel that falls between the tubes 17
from the chamber 1, where it is burned by air admitted to the chamber 39 through
the door 28; air enters the chamber 26 through the opening 26¹ passes horizontally
through the fuel in the upper part of the chamber 1, into the chamber 32 making
a partial combustion of the fuel, the products of this combustion pass thence
downwardly into the chamber 32 and horizontally through the incandescent fuel in
the lower part of the chamber 1, to the combustion chamber 33 in a state of
smokeless combustion heating the boiler 20.
In Figure 16 are shown several constructions of the perforated walls of the fuel
chamber 1. The central portion is formed of water tubes 42, connected at the top
and bottom to manifold branched tubes 43 and 44 having pipes 45 and 46 to connect
then with the water spaces of the boiler; at the left portion of the figure are
shown vertical water tubes 421 with perforated refractory tiles 47 fitted between
them, and in the right portion of the figure, it is shown constructed of perforated
refractory tiles 48 near the upper part and near the centre of its height of refractory
tiles 49, set with air spaces between them, whilst below these are shown refractory
tiles 51 having grooves 52 in them forming their spaces when assembled.
Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
•
1. A new and improved method and process of utilising solid fuel consisting in
progressively passing such fuel through a retort, chamber, or vessel and repeatedly
pasting across and through such fuel currents of aëriform fluid with products of
previous combustion, so that the fuel which has been previously but partially
consumed with the first passage of air through it, is further consumed by a second
and further passage of the products of previous combustion, and so on, until
exhausted, and the entire combustible portion converted into gas susceptible of
smokeless combustion, substantially as set forth.
2. In a furnace adapted to a boiler for the smokeless combustion of fuel, and
generation of steam, a furnace chamber having a grate adapted to move fuel
progressively from the point of entrance rearwardly, and an air supplying ash pit,
arranged to supply a rising air draft under the portion of the grate receiving new
fuel in combination with a water tube rear grate in fluid connection with the boiler,
and a downward draft or gas chamber under said rear grate, arranged to receive
and consume the fuel previously partly burned by the rising draft substantially as
set forth.
3. In a furnace for smokeless combustion of fuel and the generation of com-
bustible gases, a magazine arranged to continuously supply fuel to the furnace, a
grate arranged to progressively convey fuel as deposited from said magazine, and
distribute the same over said grate, in combination with an ash pit arranged to
supply a rising air draft to fuel on the portion of said grate contiguous to the
magazine, and a gas chamber arranged to draw products of combustion downwardly
from the furnace chamber through the partially burned fuel on the portion of the
grate remote from the magazine substantially as set forth.

page_text: 4. In a furnace for generating steam by the smokeless combustion of fuel, '
furnace chamber and means of supplying fuel at one end thereof, a grate arranged
to distribute fuel upon said grate and convey the fuel in the course of combustion
over, an ash pit arranged to supply a rising air draft, and a chamber arranged to
draw products of combustion downwardly through the fuel upon another portion
of said grate, forming a fuel chamber, in combination with said chamber arranged
to receive partially burned fuel and intercept and heat all air drafts to the boiler
and incandescent fuel in said chamber, and discharge cinders, and incombustible
residuum substantially as set forth.
5. In an apparatus for generating steam by the smokeless combustion of fuel,
a furnace chamber, means of progressively supplying the fuel thereto, and an
upward air draft to said fuel, an extension of said furnace chamber formed of water
tube grates and arranged to be constantly filled with partially burned fuel in
incandescent condition as received from the furnace chamber and thereby intercept
and heat all air drafts towards the boiler in combination with one or more
chambers arranged to draw the products of the first combustion one or more times
through the incandescent fuel and deliver them to the boiler, as and for the
purposes set forth.
Dated this 3rd day of July 1894.
FELL & WILDING,
Agents for the Applicant.