IMPROVEMENTS IN FURNACES AND GRATES FOR STEAM GENERATORS
Year: 1881

page_text: LETTERS PATENT to William Lloyd Wise, of 7, Whitehall Place, in the
City of Westminster, for an Invention of "IMPROVEMENTS IN FURNACES AND
GRATES FOR STEAM GENERATORS." A communication from abroad by George
Edward Palmer and Amasa Worthington, both of Chicago, County of Cook,
in the State of Illinois, one of the United States of America, and George
Addison Rowell, of Brooklyn, County of Kings, in the State of New York,
one of the United States of America.
PROVISIONAL SPECIFICATION left by the said William Lloyd Wise at the
Office of the Commissioners of Patents on the 20th December 1881.
WILLIAM LLOYD WISE, of 7, Whitehall Place, in the City of Westminster:
"IMPROVEMENTS IN FURNACES AND GRATES FOR STEAM GENERATORS." (A com-
munication from abroad by George Edward Palmer and Amasa Worthington, both
of Chicago, County of Cook, in the State of Illinois, one of the United States of
America, and George Addison Rowell, of Brooklyn, County of Kings, in the State
of New York, one of the United States of America.)
According to this Invention there is employed an inclined grate formed of broad
bars lying flat-wise, and extending across the incline. This grate is divided hori-
zontally in sections, with provisions for moving alternate sections to promote a
traverse of the fuel from the upper to the lower portion of the grate as required.
The fuel is supplied through a hopper extending across the whole front which is
the upper side of the grate. It becomes heated by its contiguity to the furnace,
and so soon as it touches and begins to receive air through the grate and through
apertures formed in a box or casting running across the furnace behind the feed
hopper, its gas ignites and burns, but the supply of air at this stage is too little for
complete combustion.
There is employed a register or valve which controls the quantity of air admitted
through the perforated box in the top of the first chamber of the furnace.
The gaseous products, if anthracite, coke, charcoal, or other tolerably pure carbon

page_text: is employed, are not carbonic acid, the product of complete combustion, but
carbonic oxide, a product of only partial combustion.
It is proposed to use in this furnace mainly those varieties of coal, which, when
heated, give off large volumes of volatile combustible matter; in other words, to
use the bituminous or blazing coal. In the treatment on the upper portion of the
inclined grate, only partial combustion is attained, but a large proportion of the
volatile material is given off, and rises mingled with carbonic oxide, both gases
capable of further and intense combustion under proper conditions.
If these gases are allowed in this condition to strike the cooler surfaces of the
boiler, they part with their heat, and escape unconsumed into the atmosphere,
producing visible and offensive smoke.
The back sides and top of the front chamber, and the back sides and front of
the second chamber are fire-brick, and accumulate heat so that the combustion
proceeds under unusually high temperature.
The cool surfaces of the boiler are defended by a coating of fire-brick against
the contact of the gases in this condition. The furnace has what I term a deep
hanging bridge of fire-brick or analogous material capable of enduring a high
temperature which divides its upper portion into two compartments or chambers.
In the first chamber, the combustible gases are liberated and mixed with air, as
above stated, and the whole at a high temperature brought to such condition that
on its passage under the hanging bridge and and receiving additional air, complete
combustion with the production of intense heat ensues.
The gradual descent of the fuel on the inclined grate is caused by imparting to
the alternate movable sections of the same a proper intermittent or continuous
shaking motion. For this purpose the said movable sections are mounted on a
common frame or frames supported on levers or arms, which extend from sleeves
capable of turning on fixed shafts, and to which a rocking motion is imparted by
means of a lever extending from one of said sleeves, and moved either by hand or
by a mechanical device, such as a crank connected to the lever by means of a
chain or rod, or the like.
There is provision for conveniently shifting the point of connection from a
constantly revolving crank to the shaking lever so as to shake the grates
automatically to adjustable extents.
Extending rearward from the lower extremity of the inclined grate, and forming
the bottom of the second chamber of the furnace is arranged a stationary horizontal
or nearly horizontal grate upon which the fuel falls after completing its descent on
the inclined grate. On arriving upon the said stationary grate, the fuel has
assumed more or less the condition of coke, and aided by the very liberal supply of
air rising through the stationary grate produces a very high temperature, and
intensely heats the excess of air rising through the same.
A slicing space is allowed below the lower edge of the inclined grate to facilitate
cleaning the horizontal grate.
The volatile matter rising from the fuel on its descent on the inclined grate in
the first chamber and the gases of partial combustion formed therein have no
other way of escape than under the hanging fire-bridge, and into the second
chamber. But in passing under the said fire-bridge, these gases are forced directly
into contact with the intensely hot fuel on the stationary grate, and the air rising
through the latter mixes with said gases under the most favorable conditions,
causing complete combustion of the gases, and insuring a very high degree of
heat.
The hanging fire-bridge which separates the first or front chamber from the
second or rear chamber is supported by a large tube extending across the furnace,
and the ends of which are connected at different levels with parts of the boiler.
In order to protect this tube against the excessive heat, and to prevent oxidation
it is covered with fire-brick or other analogous material. Thus conditioned, the
tube serves the double purpose of supporting the hanging bridge and of adding
materially to the heating surface of the boiler.

page_text: As above stated the heat produced by the burning of the coked fuel on the
horizontal grate as well as by the combustion of the gases passing from the front
into the rear chamber of the furnace is very intense and there would consequently
be danger of injury from that source to the lower part of the inclined grate the
foot of which reaches over the front part of the horizontal grate. To avoid mischief
arising from these conditions that small part of the horizontal grate which reaches
forward under the foot of the inclined grate is covered with a dead plate upon
which accumulates a sufficient quantity of cinders and ashes or half-burnt material
which remaining in a relatively cool state protects the foot of the inclined grate
against injury.
The improved furnace and grate may be applied to various styles of steam
generators but it is more particularly adapted for the kind of tubular boilers
known under the name of "Babcock & Wilcox boilers" and which consist mainly
of a steam or separating barrel provided with a steam dome and a set of inclined
tubes running backward and downward from the front toward the rear of the
generating apparatus under the barrel such tubes being connected at their
extremities with cast-iron or other chambers which in turn are connected respec-
tively to the front and rear end of the separating barrel insuring by this arrange-
ment a continuous and reliable circulation of the water.
When the Invention is used with this kind of boiler a platform from the
hanging bridge above described is made to extend horizontally forward directly
below the inclined tubes thus constituting a platform which effectually prevents
all contact of the gases generated in the first furnace chamber with any part of the
boiler before such gases have passed under the edge of the hanging fire-bridge or
under the transverse tube supporting the latter and in order to keep the hot gases
coming from the second furnace chamber sufficiently long in contact with the
heating surfaces of the boiler so that they part with nearly all their heat com- .
municating the same to the heating surfaces and also in order to present the gases
on their way to the smoke-stack in the most favorable manner to the said heating
surfaces for obtaining these results one or more additional fire bridges rising from
the bottom of the furnace up through the inclined tubes or descending from the
crown of the furnace through the said tubes as the case may be and preferably at
right angles therewith are arranged behind the second chamber of the furnace
the first rising fire-bridge forming at the same time the rear wall of the said
second furnace-chamber. From the foremost of these additional fire-bridges
extends forward a nearly horizontal platform in similar manner as from the first
hanging fire-bridge. The same is suitably arranged above the inclined tubes so as
to compel the escaping gases to bathe the entire surface of the inclined tubes as
uniformly as possible traversing them at right angles or nearly so till they finally
escape into the stack.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Lloyd Wiso in the Great Seal Patent Office on the 7th
June 1882.
"
WILLIAM LLOYD WISE of 7 Whitehall Place in the City of Westminster
"IMPROVEMENTS IN FURNACES AND GRATES FOR STEAM GENERATORS' (A com-
munication from abroad by George Edward Palmer and Amasa Worthington both
of Chicago County of Cook in the State of Illinois one of the United States of
America and George Addison Rowell of Brooklyn County of Kings in the State
of New York one of the United States of America.)
According to this Invention there is employed a grate which is divided into two
portions, the first portion descending from the front rearward, whilst the other
portion extends horizontally or nearly so backward from near the foot of the
first portion. These two portions may be termed separate grates, and will be so
described. The inclined portion of the grate is composed of broad bars lying
flat-wise with provisions for moving alternate sections horizontally, to promote a
-traverse-of-the-fuel-from-the-upper to the lower portion of the grate as required.
The fuel is supplied through a hopper extending across the whole upper side of the
grate. It becomes heated by its contiguity to the furnace and so soon as it begins
to receive air through the grate it ignites and burns, but the supply of air at this
stage of its progress is too little for complete combustion. The gaseous products,
if anthracite, coke, charcoal or other tolerably pure carbon is employed, are not
carbonic acid, the product of complete combustion, but carbonic oxide, a product of
only partial combustion.
The fuel is introduced at intervals or as the fireman finds occasion, placing it in
a hopper arranged above and in front of the inclined grate. It descends upon the
grate in a proper stratum as the grate is worked.
It is proposed to use in this furnace mainly those varieties of coal which, when
heated, give off large volumes of volatile combustible mater; in other words, to use
bituminous or blazing coal. In the treatment on the upper portion of the inclined
grate only partial combustion is attained, but a large proportion of the volatile
material is given off and rises mingled with carbonic oxide, both gases capable of
further and intense combustion under proper conditions.
If these gases are allowed in this condition to strike the cooler surfaces of the
boiler, they part with their heat and escape unconsumed into the atmosphere
producing visible and offensive smoke.
The cool surfaces of the boiler are defended by a coating of fire-brick against the
contact of the gases in this condition. The furnace has what is termed a deep
hanging bridge of fire-brick or analogous material, capable of enduring a high
temperature, which divides its upper portion into two compartments or chambers.
In the first chamber the combustible gases are liberated and mixed with air, and
the whole at a high temperature brought to such condition that on its passage
under the hanging bridge, and receiving additional air, complete combustion with
the production of intense heat ensues.
The air supplied to this volume of combustible gas in the second chamber of the
furnace is itself at a high temperature. What takes place there is really the
combination of a hot mixture in which there is an excess of the combustible gas,
with a hot mixture in which there is an excess of air.
There is employed also a horizontal grate, favorably conditioned for the burning
of the partially spent coke descending from the inclined grate immediately at the
foot of which it is placed. A dead plate at the front edge of the horizontal grate

page_text: serves to check the draft at the line of junction, and thus avoids a considerable
difficulty experienced from over-heating the grate at that point.
Arrangements are made for shaking the grate automatically and for adjusting
the extent of such motion as the varying conditions at different times may
require.
There is a provision for admitting air in small streams, in regulated quantities,
in the front of the first chamber of the furnace. This aids in securing the proper
quantities of air without much excess, when the gases are freely mingled for the
complete burning.
The boiler used is the "Babcock & Wilcox," composed of a separating vessel and
a series of inclined water tubes below, connected at the ends to allow free
circulation, the highest ends of the tubes being at the front.
The intensely hot gases resulting from the complete combustion in the second
chamber of the furnace rise among the tubes of the boiler imparting their heat
rapidly thereto. There is a platform of fire-brick over the first chamber of the
furnace at the level of the lowest tube. There is a partial platform at a higher
level. The hot gases rising among the tubes are compelled to travel forward
between these platforms before they are allowed to pass rearward.
The gradual descent of fuel on the inclined grate is caused by the imparting to
the alternate sections of the same, which are movable, a backward and forward
motion. To allow this, the movable sections are mounted on a frame or frames,
supported on arms or levers which extend upward from rocking shafts. To these
levers an oscillating motion is imparted by means of a lever extending forward
from one of the shafts.
This lever may be moved up and down by hand if desired. It is proposed to
employ a shaft extending transversely in front of the boiler at a proper elevation
above the lever, and carrying a crank which is connected by a chain to the lever,
and thus to shake it to the proper extent by power. The extent of the motion
thus imparted may be varied by shifting the point of connection of the chain to
the lever.
A metallic pipo is extended across the furnace at the bottom of the hanging
bridge. It is connected to the boiler so that the water cireulates through it. This
pipe performs two functions:-It increases the heating surface of the boiler, and
thereby adds to its steam generating efficiency, and it also serves as a reliable
girder to support the hanging bridge. The fire-brick or other non-conducting
inaterial of the hanging-bridge, rests upon this pipe, which supports or aids to
support it.
The pipe is enclosed within a pipe or coating of fire-clay, or analogous non-
conducting material.
It has been demonstrated by experiment that the construction and mode of
operation shown, results in a complete burning of all that is combustible in the
fuel with little labor or skill. An occasional shaking of the movable portion of the
grate, and the supplying of a liberal quantity of coal in the hopper at the upper
edge of the grate, results in a rapid combustion of the fuel, and the utilization of
the full measure of heat which the fuel is capable of producing. A marked gain
results from tho Invention. What is believed to be the correct theory is presented
herein, but it is not intended to rest the claim on the correctness of the theory.
The accompanying Drawings form a part of this Specification, and represent
what are considered the best means of carrying out the Invention.
Figure 1 is a central longitudinal section through the entire furnace and
boiler.
Figure 2 is a central longitudinal section through the main portion of the
furnace on a larger scale.
Figure 3 is a front view of the same partly in section.
Similar Jetters of reference indicate corresponding parts in all the Figures.
The boiler is of the long-approved tubulous construction, the “Babcock &

page_text: A is a barrel, a horizontal cylinder of twenty (20) or more inches in diameter.
There may be a number of these barrels side by side, but only one is shown. B is
a scries of inclined tubes, say four (4) inches in diameter. C and D are connections
which allow a constant circulation from the barrels A, down through D, forward
through B and up through C. E is a mud-drum extending across under the rear
and connected at a sufficient number of points.
G is a horizontal transverse tube of say six (6) inches in diameter. It is con-
nected by pipes g', g³, with the other portions of the boiler. The pipe g¹ leads
from the back connection D and brings water into one end of the pipe G. The
pipe g leads upward from the other end of G and conveys into the barrel a current
of water liberally mingled with steam, which is generated during the passage
through the pipe G.
An inclined grate is employed having horizontal grate bars assembled in two
systems, cach system having horizontal-bars arranged in groups which alternate
with the bars of the other series. That is to say, there are five stationary bars I
at the top of the incline, then a considerable interval and five more stationary bars
similarly marked, at a lower point, then an interval and five more, and so on.
These bars are bolted to or otherwise supported on the fixed work at the sides, and
are never moved except in repairing or exchanging. Another system J, is in
similar divided sets, having a corresponding number of horizontal bars connected
together on a sufficient framing J1, with freedom to be moved considerably forward
and back. K, K', are levers, or movable arms extending upward from sleeves K,
-and-engaging-with-J Thesc-sleeves-are-free-to-rock-or-oscillate-on-sufficient.fixed
shafts or round bars. The lowermost sleeve K has a socket which receives a
hand-lever L.
By moving the lever L up and down, either constantly or at intervals, the entire
series of levers K¹, K', is rocked, and the alternate sections of grate J are moved
forward and backward between the fixed sections I.
W, W, is a crank-shaft rotated slowly by a belt or gearing from the engine, not
represented. X is a loop of small chain leading from the crank W, and taking
hold of the hand lever L. When this chain is thus engaged it will automatically
rock the grate. The point of connection of the chain X with the lever I may be
shifted inward and outward and thereby the extent of the motion varied. When
it is shifted outward to its farthest extent, the movement is only sufficient to take
up the lost motion in the connections, and there is no actual shaking of the grate.
When it is shifted inward but little, the grate is shaken slightly by the moderate
rotation of the crank. Under many conditions the attendant may, after a few
trials, find a point in which this chain may be so adjusted that the fuel will be
slowly worked down on the grate automatically, as required.
M is the front side of a sufficiently capacious hopper, into which the fuel is
introduced either constantly or at intervals.
The back face of the hopper is an inclined hollow casing O, of cast iron or other
suitable material, through which atmospheric air is distributed into the furnace
through apertures o.
The air is admitted to the case O at one or both sides of the
furnace, through an adjustable register N.
P is a horizontal grato extending from the inclined grate I, J, to the bridge-wall
or back masonry F, which bounds the fire space. This grate P is mounted
sufficiently below the inclined grate, as indicated, to allow of slicing between.
A considerable part of the front side of the grate P, is covered by a dead plate P¹.
Ordinary provisions, not shown, allow this grate P to be shaken or dropped when
necessary.
The pipe G forms the lower edge of a hanging bridge which is composed of fire
brick or other suitable refractory material R, and extends up to the lowermost of
the inclined tubes B. The spaces between these lowermost tubes B, from the top
of this bridge R, forward, are closed by fire bricks or other suitable non-conducting
material R, forming a nearly horizontal tight platform. This platform or
flooring R', which may be termed the lower platform, and the nearly vertical

page_text: bridge R, with the stout water tube G at the base of the latter, perform the
important function of separating the front portion of the fire chamber from the
rear portion thereof, and from the space between the tubes above. They compel
the gases rising from the upper and main portion of the inclined grate I, J, to
descend and pass close to the surface of the more advanced and thoroughly coked
fuel on the lower portion of the inclined grate I, J, and on the horizontal grato P.
Care must be taken to rock the lever L sufficiently to move the fuel down, but
not so much as to move it too fast and cause it to accumulate too thickly at the
bottom. A sufficient space must be left for the gases generated in the front
chamber, to pass under the pipe G, and consequently under the entire hanging
bridge G, R, into the rear chamber y.
At this point they meet and mingle with a current of hot gases composed largely
of atmospheric air, which has passed up through the coke and cinder resting on
the horizontal grate P, in the base of the furnace. The combustible elements in
the solid portions are completely burned by receiving a large excess of fresh air
through the grate P. The gas rising from the fuel on P, has much free oxygen.
The two opposite grades of gas mingle and complete the combustion of the volatile
elements in the chamber y in rear of pipe G. The combustion is unusually intense.
The flame is bright and short.
It will now be seen that all the volatile elements of the fuel are utilized by
disengaging them in the front chamber and sending them downward and rear-
ward at a high temperature mingled with not nearly air enough for the combustion,
and then presenting them in the chamber y to a current of highly heated but
relatively fresh air at a high temperature, which has been inducted through the
thoroughly utilized solid fuel at the bottom. It is easy to so conduct this operation
that the combustion will be complete; nothing being left on the grate P but
earthy matter, and nothing going up the chimney but completely burned gases.
The hot gases resulting from the complete combustion in the chamber y, move
upward through the zig-zag spaces between the tubes B and are, by the cross-
partition T and a nearly horizontal connected platform T', compelled to traverso
forward. They move upward past the front edge of what may be termed the
upper platform T", then rearward, bathing the barrels A, then downward between
the cross-partition T, and another cross-partition U, imparting more of their heat
to the tubes B, and after moving rearward in the space under the latter, they rise
and again traverse through the zig-zag spaces between the tubes B and are
discharged into the stack not represented.
The dead-plate P' which covers the front portion of the horizontal grate serves
to accumulate a sufficient quantity of cinder and ashes, or of fuel in a half-burned
condition, and to hold such matter there in a relatively cool state. By reason of
this fact, a considerable space may be allowed between the lower edge of the
inclined grate and the top of the grate P, without realizing such a heat there as
to melt the iron or do any other mischief.
L' is a portable weight provided with a hook or other convenient means of
attachment, which may be removed whenever it is desired to shake the lever L,
and consequently the frame Jand bars J by hand. The chain X being removed
either by slipping its loop off the end of the hand-lever L, or by disconnecting a
hook or other simple attachment from the lever L, or from the crank W¹, or from
both; the lever L may be vibrated up and down as vigorously as the exingency
shall require. Under favorable conditions, the chain X being connected to the
crank W at the top, and to such point in the hand-lever L, as shall be found to
give such sufficient reciprocation to the lever, a moderate motion may be maintained
constantly. The lever L may be notched on the underside to hold the chain
against shifting its position, and also, if desired, on the upper side to hold the
weight L in position.
Modifications may be made in the forms and proportions within wide limits.
The angle of the fresh air casing O, may be adjusted by the employment of chipping
pieces at the surfaces of contact, which can be chipped off, filed or otherwise

page_text: changed, as experience with a given kind of fuel shall dictate. Some success may
be attained without the use of the casing O. A greater or less number of bars
may be introduced in each of the horizontal sections I, J. If desired every alternate
bar may be made stationary, and every intermediate bar movable. But the
arrangement shown with alternate sets or groups of five or about that number
movable and a corresponding or nearly corresponding number stationary, is
preferred. It is also practicable to move all the parts of the inclined grate equally
and simultaneously, the bottom grate being stationary, or to move the bottom
grate while all the parts of the inclined grate are stationary.
Bituminous coals vary greatly, not only in their chemical constituents but in
their mechanical conditions in burning. Those which remain as hard lumps may
be worked differently from others which become pasty when exposed to heat, and
both are materially different from some grades which flake off or change to fine
scales or powder, before they are fully burned. Large lumps of coal may require a
removable cover on the hopper, M, to prevent air from entering the furnace through
the large interstices.
The throw of the crank W' may be varied by shifting the crank-pin in a radial
slot or otherwise, so as to vary the extent of motion of the chain X. In place of
the chain X a rigid link with a hook or other ordinary means of engaging with
the lever L may be substituted. Another lever may be employed to serve in this
relation, independent of the hand-lever L. It is deemed important that the
automatic motion be capable of easy adjustment, and also of being thrown out of
-use-entirely, to allow the grate to be shaken by hand when desired.
Much importance is attached to the fact that the hanging-bridge R and the lower-
platform R¹ are not water surfaces, but fire-brick or analogous material adapted to
assume and maintain a high temperature, so that the fuel will be first distilled
into combustible gas and burned into carbonic oxide at a high temperature, and
then that the gases thus produced, will, after passing under the hanging bridge, be
exposed to and mingled with the hot gases rising from the lower portion of the
furnace containing an excess of air, under such conditions that all the particles
will be there thoroughly combined, producing carbonic acid. The water tube G is
encased in suitably formed fire-bricks to prevent it from direct exposure to the hot
gases, and thus avoid the refrigerating effect which it would otherwise produce.
The furnace having the properly formed chambers x, y, thus bounded by surfaces
which may be raised to a very bigh temperature, is very different from any,
however closely approaching it in form, in which the surfaces are naked portions of
a boiler filled with water, and consequently maintained at a relatively low
temperature.
It is important that the chambers be so proportioned as to allow a proper space,
with no great surplus of space for the two operations, that is to say, the production
of hot combustible gas in the first chamber and the burning it completely under
the conditions prescribed in the second chamber 3. The proportions may require
to be varied with different kinds of fuel and different conditions with regard to
draft. Experiments indicate the proportions shown as about right for using soft
coal from the Illinois bed, burned with natural draft.
Parts of the apparatus may be used without the whole, but it is preferred to
employ the whole combined and arranged as shown. Where a number of the
furnaces are employed side by side, one shaft W may extend across the front of
the whole, with a crank W1 introduced at the front of each furnace.
What is claimed as new is:
First. An inclined grate having transverse bars lying nearly or quite flatwise, a
portion being mounted stationary and another set, mounted in spaces between,
being movable horizontally, as herein specified.
Second. The bottom grate P, with its front dead plate P' in combination with a
separate inclined grate with means for moving a portion of the latter forward and
backward, as herein specified.
Third. In combination with an inclined grate with provisions for shaking the

page_text: whole or a portion of the same, the adjustable connexion X, leading from a
uniformly moving part W to a lever L, substantially as herein set forth.
Fourth. The combination of an inclined grate I, J, with provisions for shaking
a part, a feeding hopper M for supplying fuel thereto, and a horizontal grate P for
burning the residue and a hanging bridge R arranged to induce a mixture and
complete combustion of the gases, as herein specified.
Fifth. The hanging bridge R and lower platform R', in combination with the
back-masonry F, partition T and upper platform T' and with the boiler A, inclined
tubes B, and connections C and D, substantially as herein specified.
Sixth. The case O, having provisions for receiving and distributing air, arranged
at the front of the furnace and receiving air in adjustable quantities from the side
or sides, in combination with a hopper and with an inclined grate as herein
specified.
Seventh. In a furnace formed in two partly separated chambers, the first lined
with non-conducting material on all sides and above, and the second similarly lined
on all sides, an inclined grate with provisions for feeding fuel slowly down thereon,
a hanging bridge and a transverse pipe G, having connections g₁g³, to a steam
boiler A, combined and arranged to serve as herein specified.
Eighth. In a steam boiler furnace, a grate, as I, J, P, in two parts, the front part
being downwardly inclined and the rear part being horizontal or nearly so, in
combination with provisions for moving a portion of the grate, and with the
hanging bridge R and platform R', substantially as and for the purpose herein
specified.
Ninth. The method herein described of first exposing fuel in one chamber to
distillation of the volatile matter and partial combustion of the solid material, then
subjecting the solid residue to complete combustion in another chamber with an
excess of air, so that the resulting gases contain much free oxygen at a high
temperature and finally mingling the two kinds of heated gases, all in chambers
having a non-conducting lining so as to retain the heat and attain completo
combustion by three successive stages, substantially as herein specified.
In witness whereof, I, the said William Lloyd Wise, have hereunto set my
hand and seal, this Seventh day of June, in the year of our Lord 1882.