Improvements in Furnaces for Steam Generators, and for other Uses.
Year: 1895

page_text: Date of Application, 9th Feb., 1895
Complete Specification Left, 27th June, 1895-Accepted, 3rd Aug., 1895
PROVISIONAL SPECIFICATION.
Improvements in Furnaces for Steam Generators, and for other Uses.
We, ROBERT BRUCE CARSLEY, of Keyport, in the County of Monmouth,
and State of New Jersey, United States of America, Engineer, and JOHN HALES
BETTS, of the same place, Gentleman, do hereby declare the nature of this
invention to be as follows:-
Our invention relates broadly to furnaces for general purposes, but is especially
applicable for use with steam generators.
The object of the invention is to promote perfect combustion in the fire-box of
the furnace and thereby to effect an important economy in fuel, as well as,
incidentally, to prevent the generation of free carbon in the form of smoke. We
accomplish these results partly by an accelerated forced draft, partly by the
introduction into the furnace, at the proper points, of steam in the form of a
permanent gas at a relatively high temperature, whereby an incandescent heat is
obtained through the combustion of hydrogen gas, and partly by a peculiar
construction of the fire-bed, all as hereinafter described.
66
Our purpose is, in general, to produce a furnace having a fire-bed made up
wholly of rotary, interlocking, hollow bars, adapted to receive steam and air and
to deliver it in jets to the fuel resting on the bars, thereby producing what we call
a cyclone draft. These bars are mounted at their ends in sliding blocks, which
blocks are mounted in cross-bearers or tracks and are coupled by levers arranged as
lazy-tongs," so that, by rotation or rocking of a shaft geared to said tongs, the
bars may be shifted laterally, in order to set them closely together or separate them
more or less. Above the level of the fire-bed, and within the combustion chamber
of the furnace, we arrange a steam-superheating device, consisting of a pipe which
enters the combustion chamber and passes round the same near the walls; one
cross-branch thereof being parallel and adjacent to the bridge-wall, and another
passing across the front above the charging door; this latter branch having
jet-apertures whence gaseous steam issues over the fuel on the fire-bed. In such a
furnace we may and do burn slack or culm from bituminous coal without the
generation of smoke; and we produce with it, as well as with other carbonaceous
fuels, incandescent, gaseous ignition throughout the combustion chamber, with full
and complete gaseous combustion. This result we conceive to be due in part to
the decomposition of the gaseous steam introduced through the grate bars, and up
through the bed of incandescent carbonaceous matter thereon; in part to the
peculiar gyratory forced draft which brings the gases forming the draft into
contact with all parts of the bed of incandescent fuel, and in part to the
decomposition of the gaseous steam introduced above the fire-bed; the elements
thereof combining above the carbonaceous fuel to produce an incandescent heat,
due, as we believe, principally to the large volume of hydrogen developed from the
steam.
The fire-bed or grate is made up wholly of rotary grate-bars, placed side-by-side,
and each having spiral flanges resembling screw-threads; the flanges ou a:ljacent
bars intermeshing, and those of every alternate bar having flanges of convex
cross-section which engage with concave interspaces between the flanges on the
intermediate bars. The spirals on the bars are, alternately, inclined in opposite
directions, like right and left-hand screw-threads, and mechanism, such as
worm-gearing, is employed to impart rotative motion to all the bars simultaneously.

page_text: The bars are mounted, as stated, in sliding journal blocks, so that the spaces
between adjacent bars may be varied. The bars are, moreover, hollow, and means
are provided for admitting, to each bar independently, steam, or steam and air
combined; said steam or steam and air passing up to the fuel on the grate through
jet-apertures in the bars. Means are also provided for preventing the pipes for
admitting steam to the several bars from interfering with the lateral shifting of the
bars by the lazy-tongs devices. The blocks in which the bars arc journalled are,
by preference, mounted on balls to reduce the friction.
In the combustion-chamber, above the fire-bed, is arranged a pipe which passes
round the chamber near the four walls thereof. This pipe is supplied with boiler-
steam, which, in passing through said pipe, is superheated until it has the character
of a permanent gas, and in this condition it is emitted in jets from apertures
formed in the branch across the front of the combustion-chamber; the jets being
directed backwards over the incandescent fuel on the grate. This arrangemen
produces incandescent gas-combustion in the combustion chamber, prevents the
formation of smoke, and produces the intense heat due to the chemical union of
the oxygen and hydrogen.
The forced draft produced by the steam and air through the rotary bars
produces a gyratory or cyclone draft, and the bars are maintained at a temperature
below that which would injure them.
The bars may be brought into close contact so as to support dust-like fuel, and
the forced draft be relied on to promote combustion.
Dated the 9th day of February 1895
COMPLETE SPECIFICATION.
Improvements in Furnaces for Steam Generators, and for other Uses.
We, ROBERT BRUCE CARSLEY, of Keyport, in the County of Monmouth and
State of New Jersey, United States of America. Engineer, and JOHN HALES
BETTS, of the same place, Gentleman, 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 :-
Our invention relates broadly to furnaces, but particularly to boiler-furnaces,
and we have illustrated it herein as embodied in a boiler-furnace.
The object of the invention is to promote perfect combustion in the fire-box of
the furnace and thereby effect an important economy in fuel, as well as, incidentally,
to prevent the generation of free carbon in the form of smoke. These results we
attain partly by an accelerated forced draft, partly by the introduction into the
furnace at the proper points, of steam in the form of a permanent gas at a relatively
high temperature, whereby an incandescent heat is obtained through the combustion
of hydrogen gas, and partly by a peculiar construction of the fire-bed, all as will
be hereinafter described.
In the accompanying drawings, which illustrate an embodiment of our invention,
Fig. 1 is a front elevation of the furnace as applied to heating a steam-
generator.
Fig. 2 is a longitudinal section of the same, taken on the line 2, ², in Fig. 1.
Fig. 3 is a horizontal section, taken ou the line ³, ³, in Fig. 4.
Fig. 4 is a transverse section on line, a, in Fig. 2.
Fig. 5 is an enlarged detail view illustrating the mechanism for shifting the
rotating grate-bars laterally; and
Fig. 5 is a cross-section of same on line a, a, in Fig. ɔ̃.

page_text: appurtenances.
Figs. 7, 74 and 7B are views illustrating, in detail, the construction of the
appliances for supplying the combustion chamber with superheated steam in the
form of a permanent gas.
In the drawings, we have designated the steam-generator, and the ordinary
parts of the furnace connected therewith, by reference letters, and the parts of
the furnace which embody our invention, by reference numerals.
A is an ordinary steam-boiler. B is the furnace-front, provided with a charging
door or doors C, and ash-door D. E is the combustion chamber above the
fire-bed, F the ash-box below the fire-bed, and G the bridge-wall at the back or
rear of the fire-bed. All the above parts are, or may be, those common to boilers
and boiler-furnaces.
Our purpose is, in general, to produce a furnace having a fire-bed made up
wholly of rotary, interlocking, hollow bars, adapted to receive steam and air and
to deliver it in jets to the fuel resting on the bars, thereby producing what we call
a cyclone draft. These bars are mounted at their ends in sliding blocks, which
blocks are mounted in cross-bearers or tracks and coupled by levers arranged as
"lazy-tongs," so that, by the rotation or rocking of a shaft geared to said tongs,
the bars may be shifted laterally, in order to set them closely together or separate
them more or less. Above the level of the fire-bed, and within the combustion
chamber of the furnace, we arrange a steam-superheating device consisting of a
pipe which enters the combustion chamber and passes around the same near the
walls; one cross-branch thereof being parallel and adjacent to the bridge-wall, and
another branch being disposed across the front, above the charging door C; this
latter branch having jet-apertures from which the gaseous steam is thrown out
over the fuel in the fire-bed. In such a furnace we may and do burn slack or
culm from bituminous coal without the generation of smoke; and we produce with
it, as well as with other carbonaceous fuels, incandescent, gaseous ignition throughout
the combustion chamber, with full and complete gaseous combustion. This result
we conceive to be due in part to the decomposition of the gaseous steam introduced
through the grate-bars and up through the bed of incandescent carbonaceous matter
thereon; in part to the peculiar gyratory forced draft, which brings the gases
forming the draft into contact with all parts of the bed of incandescent fuel; anu,
in part, to the decomposition of the gaseous steam introduced above the fire-bed;
the elements thereof combining above the carbonaceous fuel to produce an
incandescent heat, due, as we believe, principally to the large volume of hydrogen
developed from the steam.
The fire-bed or grate is made up wholly of rotatively mounted grate-bars, 1,
arranged side-by-side and extending from front to rear. In Fig. 3 is shown a
set of bars in position on a rather small scale, but in Fig. 6, two adjacent bars
are shown drawn to a larger scale; the latter view being referred to for details.
Each bar 1 resembles, externally, a four-threaded screw; that is, it has four
spirally arranged flanges or worms, which are separated by grooves.
The spirals
or worms of adjacent bars are alternately inclined in opposite directions, one being
like a right-hand screw and the next adjoining one like a left-hand screw.
The
spirals or worms 2, of one bar are, moreover, rounded or convex (as seen in
horizontal section), while the adjacent bar has grooves or concave interspaces 2*,
between its thinner flanges or worms. In other respects than this the bars are
alike. Each bar is hollow, or has in it a bore or passage 3, which extends nearly
through it, and from this bore jet-passages 4, extend out through the shell of the
bar, opening in the interspaces or grooves between the spirals, at the upper sides
of the bars. On the outer end of each bar, at the front of the furnace, is fixed a
worm-wheel 5, and on a cross-shaft 6 (Figs. 1, 2 and 3), are worms or screws 7,
which respectively gear with the worm-wheels 5, pertaining to the bars 1, whereby,
when the shaft 6 is rotated the bars 1 will also be rotated. Under ordinary

page_text: circumstances, it is not contemplated that the bars will be actually rotated, or
turned round and round in one direction, but they may be rotated if required;
ordinarily they will be rocked to and fro through a part of a revolution, and left,
when at rest, with the jet-apertures 4 uppermost. The shaft 6 may be provided
with a crank or pulley 8, for turning it.
Each grate-bar has a journal 9, at each end, and these journals are mounted in
bearing-blocks mounted in tracks or ways, as will be described with special
reference to Figs. 4, 5 and 54. As the construction is the same at both ends
of the bars, we will describe only that at the front end, which is fully illustrated.
Extending across the furnace are two grooved tracks 10 and 11, the former above
the latter (Fig. 5), and in the grooves in these tracks are mounted bearing-blocks 12,
one for each grate-bar. The journals on the bars find bearings in the blocks 12,
which are connected together by "lazy-tongs" levers 13. At their crossing
points 14, the levers are pivotally attached to pendent lips on the respective blocks,
as seen in Figs. 5 and 54, and, in order to move the grate-bars laterally, a rack-
bar 15 is coupled at the end of the lazy-tongs and mounted in a guide 16, in the
furnace-wall. A pinion 17, on a shaft 18, gears with the rack-bar, and on the outer
end of this shaft is a handle or crank 18", whereby the shaft and pinion may be
turned. By means of this device the grate-bars may be moved apart to a limited
extent, and spaced as desired, for the purpose of clearing the grate of ashes and
clinkers and for adapting it to different kinds or grades of fuel. As before stated,
the grate-bars are furnished with the same appliances at their rear
ends as at their front or outer ends, and the shaft 18 extends back to the rear
ends of the bars and has a pinion at that end like the pinion 17. This shaft 18
is indicated in dotted lines in Figs. 2 and 3. In order to lessen the friction,
which tends to resist the movements of the bearing-blocks 12, in the grooves in
the tracks 10 and 11, we prefer to provide balls 12ª, interposed between the
blocks and tracks, as seen in Figs. 5 and 5; the blocks and tracks being broken
away in Fig. 5 to disclose the construction. The balls are arranged in pockets
in the upper and lower ends of the block in order to prevent them from
collecting together or bunching.
or inner
To prevent openings being produced between the adjacent blocks when they are
moved apart, each bearing-block 12 is provided at one side with a lapping piece 12",
which projects over the adjacent block and enables the blocks to separate to a
sufficient extent without producing an opening.
The devices for admitting steam and air to the grate-bars and furnishing a forced
draft, is best illustrated in Fig. 6. A steam-pipe 19, (Fig. 1,) supplies steam to
the grate-bars from any source. In the outer end of each grate-bar I is inserted
a steam-jet nozzle 20, about which the bar turns or rocks this nozzle is fixed at
its outer end in a valve-casing 21, provided with a valve 22, furnished with a screw-
stem and hand-wheel to enable the steam to be admitted separately to each grate-
bar. The valve-casings 21 are coupled together by steam-pipes 19*, which form
continuations of the steam-pipe 19, as clearly shown in Fig. 3. The pipe 19
supplies steam to the first valve-casing of the series, and the steam flows succes-
sively through the pipes 19* to all of the other casings. In order to allow the
grate-bars to be moved laterally by means of the lazy-tongs 13, as already
explained, without interference from the steam pipe connections, the connecting
steam pipes 19*, are each screwed or otherwise fixed in one valve-casing (see
Fig. 6), and play through a gland or stuffing-box 21*, on the adjacent valve-casing.
The steam-pipe 19 has a similar sliding connection with the valve-casing to which
it is coupled.
When steam is admitted to the grate-bar through the jet-nozzle 20, it acts as an
injector to take in air through an inlet or inlets 23, in the journal 9 of the bar, and
this air, mingled with the steam from the jet, serves to keep the bars cool, or below
an injurious temperature, to supply an abundance of combustible gas to the
furnace, and to provide a forced draft.

page_text: Referring to Figs. 2, 3, 4, 7, 7 and 7B, we will now describe the means for
introducing steam in a gaseous condition to the combustion chamber above the
fire-bed.
A steam-pipe 24, supplied from any source, enters the combustion chamber E at
the front thereof, and connects with a superheating pipe 25, which extends along
one side of the furnace, back to the bridge-wall G, thence across the chamber and
along the other side thereof, to the front wall, and thence across the fore-end of
the chamber to near the point where the pipe 24 enters, its end being stopped or
closed. This pipe 25 is liable to become deteriorated by heat and oxidation; we
therefore prefer to construct it as shown in Figs. 7 and 7ª, which are detail views
on a larger scale than the principal views. The pipe which is cast from gun metal,
or some like alloy, as iron or steel oxidizes too readily when subjected to the
combined influences of heat and oxygen, is corrugated longitudinally-
-as seen in
the cross-section at the left in Fig. 7-in order to facilitate lateral expansion and
contraction under the influences of pressure and the changes of temperature.
With a view to facilitating the renewing of the pipe, or parts thereof, and
especially with the object of avoiding the necessity for awaiting the complete
cooling of the furnace, the pipe is made in sections, as clearly shown in Fig. 3,
with simple interlocking couplings. This coupling is clearly illustrated in Fig. 7;
and in Fig. 7 is shown a face view of the female element of the coupling. The
female element 26, has formed in its face a tapered dovetail slot 26%, and the male
element 27, has formed on its face a tapered dovetail tongue 27*, adapted to drop
into and fit the slot in the other element. This simple coupling will enable a
section of the pipe 25 to be quickly removed and replaced, after being cleaned, or
by a new section.
The steam admitted to the pipe 25 is subjected to intense heat at the bridge-
wall and is converted into a highly expanded gas. This gas is emitted in jets
from apertures in the branch of the pipe which crosses the combustion chamber at
the fore-end. Fig. 7B represents portions of this branch of the pipe 25, and
illustrates two forms of jet-apertures 28. The part at the left in the figure shows
circular jet-apertures and the part at the right shows laterally elongated apertures
or slits. Either of these forms may be en.ployed, or both may be used together.
The purpose is to direct the gaseous steam in regulated quantity, and with proper
regard to distribution, rearwardly into the combustion chamber over the incan-
descent bed of fuel, so that it may mingle and combine with the hot combustible
gases arising from the fire-bed and produce gaseous incandescence. This it does,
and, in so doing, compels the combination of all the free carbon from the fuel;
thus eliminating the element of smoke and reducing the products of combustion
substantially to carbon dioxide and nitrogen.
The section or branch of the pipe 25 which crosses the combustion chamber
adjacent to the bridge-wall, may be arranged higher or lower, as the circumstances
or the character of the furnace may dictate. We have shown it arranged at about
the level of the top of the bridge-wall where it will receive the full force or
effect of the heat at this point; but it may be best in some cases to protect it
somewhat, or place it in a less exposed situation; we do not limit ourselves in this
respect.
We are well aware that, speaking broadly, it is not new to employ screw-like,
rotating bars in grates, and that it is not new to rotate such bars with screw
gearing similar to that herein shown; we are also aware that, speaking broadly, it
is not new to admit steam to a furnace through hollow grate-bars. These features
therefore we do not broadly claim as our invention. One of the distinctive features
of our invention is the formation of the entire fire-bed or grate-surface of right
and left spirally flanged bars, with means for rotating adjacent bars simultaneously
in opposite directions; and another feature is the admission of steam and air to
such bars independently in order to equalize or vary the combustion at different
points in the grate-surface. The introduction of steam, or steam and air, into the
furnace through jet apertures arranged in the interspaces between the spiral flanges

page_text: of the bars, taken in connection with the peculiar contorted passages between th
interlocking spiral flanges of adjacent bars through which air is drawn from the
ash-box by the forced draft, produces a peculiar and effective draft which we call a
cyclone or gyratory draft, and this we find especially important in effecting a
thorough combination of the combustible elements.
The employment of rounded or convex flanges 2, fitting into concave inter-
spaces 2 on the adjacent bars, enables the bars to be brought close together so
that the finest dust-like fuel may be burned at first with the forced draft alone, the
bars being afterwards gradually separated for the passage of air between them.
If the fire burns unevenly, the forced draft may be brought into full play at any of
the bars and reduced at others; this regulation of the draft at any desired point
in the width of the fire-bed being effected by the independent admission of the
steam to the respective bars.
Cocks are provided in the pipes 19 and 24, as shown in the drawings, to
regulate the supply of steam, which, as herein shown, is supplied from the
boiler A.
We are well aware that it is not new, broadly, to introduce steam to a furnace
through hollow grate-bars, and that it is not new, broadly, to provide rocking grate-
hars with interlocking flanges and with spiral flanges. All of these features are old in
themselves and we do not claim them. We are also aware that steam jets have
been employed for introducing air into furnaces both above and below the grate
and this we do not claim. We utilize these features in new combinations whereby
we attain what we believe to be new and improved results.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, we claim :-
1. A furnace-grate or fire-bed in which the fuel-supporting surface is composed
wholly of rotatively mounted grate-bars having right and left-hand intermeshing
spiral grooves and worms, those having right-hand spirals alternating in position
with those having left-hand spirals, and furnished with gearing for simultaneously
rotating all the bars, those with left-hand spirals revolving in one direction whilst
those with right-hand spirals revolve in the opposite direction, substantially as set
forth.
2. A furnace-grate or fire-bed having its fuel-supporting surface composed of
rotatively mounted grate-bars having right and left-hand interlocking worms or
spirals, the spirals 2, on one bar being convex or rounded and the groove or
interspace 2* on the adjacent bar being concave to receive the worm or spiral 2,
and having means for simultaneously rotating adjacent bars in opposite directions,
substantially as set forth.
3. A furnace-grate or fire-bed having its fuel-supporting surface composed wholly
of rotatively mounted hollow grate-bars furnished with right and left-hand inter-
locking worms or spirals, and jet-apertures in the hollows between said spirals,
means for simultaneously rotating adjacent bars in opposite directions, as described,
and means for admitting steam to the fuel through said bars, substantially as set
forth.
4. The combination with a series of hollow grate-bars arranged side-by-side and
provided with lateral jet-apertures, of means for admitting steam to the said bars,
and means for controlling and regulating such admission independently to each bar,
whereby the admission of steam to the fuel may be varied at different points in the
width of the furnace, substantially as described.
5. A furnace-grate or fire-bed having its fuel-supporting surface composed of
rotatively mounted grate-bars having right and left-handed interlocking worms or
spirals, means for simultaneously rotating said bars, those adjacent in opposite
directions, and means, substantially as described for simultaneously shifting said
bars laterally for varying the spacing between adjacent bars, substantially as set
forth.
6. In a furnace, the combination with hollow grate-bars and means for admitting

page_text: steam to the fuel in upwardly directed jets through said bars, of means substantially
as described for supplying superheated, gaseous steam alone, in rearwardly and
downwardly inclined jets to the combustion chamber above the fuel, whereby
incandescent heat is produced in said chamber, as set forth.
7. In a furnace, the combination with the bearing-blocks 12, and the transverse
supporting tracks in which they are mounted, of the rotary grate-bars, the journals
of which have bearings in said blocks, the lazy-tongs 13, connecting said bearing-
blocks, and means for operating said lazy-tongs, substantially as set forth.
8. The combination with the transverse tracks, 10 and 11. the bearing-blocks 12,
mounted therein, the lazy-tongs 13, connecting said blocks, the rack-bar 15, coupled
to said lazy-tongs, the shaft and pinion for operating said rack bar, and the guide
for the latter, of the rotatively mounted, spirally-flanged grate-bars journalled in
the respective bearing-blocks, substantially as set forth.
9. The combination with the grooved transverse tracks, 10 and 11, arranged one
above the other, the bearing-blocks 12, mounted in said tracks and provided with
lapping pieces 12, and the balls 12*, interposed between the bearing-blocks and
tracks, of the lazy-tongs 13, connecting together the bearing-blocks, the guide
rack-bar 15, coupled to the lazy-tongs, the pinion 17, gearing with said rack-bar.
the shaft of said pinion, and the spirally flanged grate-bars, rotatively mounted in
the respective bearing-blocks, substantially as set forth.
10. In a furnace, the combination with the rotatively mounted, hollow grate-
bars, having lateral air-inlets 23, of the steam-jet nozzle 20, mounted in the ends
of the respective bars, the valve-casings 21, connected with the outer ends of th:
respective nozzles 20, the valves 22, in the casings, adapted to control the admission
of steam to the nozzle from the casing, a steam supply-pipe connected with one of
the valve-casings of the series, and pipes connecting the several casings, whereby
the steam may How through the latter, substantially as set forth.
11. In a furnace, the combination with the hollow grate-bars, furnished with
spiral grooves and worms, means for rotating or rocking said bars, and means for
shifting said bars laterally to vary the interspacing, of the steam-jet nozzles 20,
mounted in the outer ends of the respective grate-bars, the valve-casings 21,
connected with the respective nozzles 20, and the stean-pipes 19x, connecting the
adjacent valve-casings, each of said steam-pipes extending through and being
adapted to play in a gland in one of said valve-casings in order to accomodate
the steam-connections to the lateral shifting of the grate-bars, substantially as set
forth.
12. In a furnace, the combination with the fuel-supporting grate, the bridge-
wall, and a steam-supply pipe 24, of the sectional superheating pipe, 25, composed
of sections provided with interlocking, tapered dovetail couplings, substantially as
described, whereby the pipe may be replaced in sections without cooling the
furnace, substantially as set forth.
13. In a furnace, the combination with the bridge-wall at the back of the
combustion-chamber and the grate for supporting the fuel, a steam generator, and
steam-supply pipe 24, connected therewith, of a sectional pipe 25, extending
around the four walls of the furnace, one transverse branch being adjacent to
the bridge-wall and the terminal transverse branch, which crosses the com-
bustion-chamber at the front, provided with jet-apertures, the pipe 24 being
connected with and adapted to supply steam only to the pipe 25, substantially as
set forth.
14. A furnace-grate or fire-bed having its entire fuel-bearing surface composed
of rotatively mounted grate-bars having right and left-hand interlocking or
intermeshing worms or spirals, and having means for simultaneously rotating or
rocking said bars, and means for shifting the same laterally, substantially as set
forth.
15. A furnace having its entire fuel-bearing surface composed of rotatively
mounted hollow grate-bars, provided with right and left-hand intermeshing worms

page_text: or spirals, alternating bars having rounded flanges 2, which engage with concave
interspaces or grooves 2* between the flanges on the other bars, said furnace having
means for introducing steam and air to the fuel through said bars, means for
rocking said bars, and means for separating said bars laterally, substantially as set
forth
Dated the 24th day of June 1895.
For the Applicants,
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.