IMPROVEMENTS IN FURNACES."
Year: 1874

page_text: LETTERS PATENT to William Alexander Lyttle, of the Grove,
Hammersmith, in the County of Middlesex, Engineer, for the
Invention of "IMPROVEMENTS IN FURNACES.""
PROVISIONAL SPECIFICATION left by the said William Alexander
Lyttle at the Office of the Commissioners of Patents with his
Petition, on the 27th August 1874.
I, WILLIAM ALEXANDER LYTTLE, of the Grove, Hammersmith, in
the County of Middlesex, Engineer, do hereby declare the nature of
the said Invention for " IMPROVEMENTS IN FURNACES," to be as follows:-
My object in this Invention is to apply to furnaces generally the
same general principles of construction and action as are observed in
my Invention of the "duplex furnace" specified in my Letters Patent
numbered 749, and dated the Twenty-eighth day of February last, the
title of which is "Improvements in the Means and Apparatus for
Smelting Iron."

page_text: In this duplex furnace the fuel is charged into a high conical chamber
and burned away by a blast which strikes against the bottom of the fuel
through an orifice provided for that purpose in the side of the fuel
chamber. This chamber being provided with an air-tight trap or hopper
on the top the blast which strikes the fuel at the bottom cannot escape
upward through the fuel chamber, and hence any gases or flame
generated by the impact of the blast against the burning fuel at the
bottom are compelled to find. vent downward and backward against the
blast by which they were produced.
In the duplex furnace described in the aforesaid Patent this point or
orifice at which the flame and gases escape through the blast from the
bottom of the fuel chamber is at one side of the crucible of a common blast
furnace, which furnace forms the second or ore chamber of the duplex
arrangement; and the flame thus generated finds no vent except by
passing upward through the ore chamber, where it supplies the required
smelting heat. By this means bituminous coal, either in lump or dust,
can, for the first time, be used for smelting iron in the blast furnace
without coking, because the contents of the fuel chamber not being
intended to afford a passage for the blast the "caking" together of the
coal will not matter, whilst all the hydrocarbon gas generated can
escape only as flame with intense heat through the orifice in which the
blast plays.
The same arrangement as regards the column of fuel or fuel chamber,
with blast either hot or cold, which is described in connection with the
aforesaid Patent, can also be applied to ironfounder's cupolas, also to
furnaces for the puddling of iron, whether the puddling chambers of
such furnaces are rotary or fixed; and to all other reverberatory furnaces
of every kind, more especially those required in the alkali manufacture.
In order to adapt the principle to such modifications it is only necessary
to so arrange the blast orifice of the fucl chamber as to ensure the issue
and play of the flame and heat exclusively into the chamber or hearth
within which the heat is required. In fact the only alteration required
in such furnaces will be to substitute the fuel chamber of the duplex
furnace with its blast arrangement for the present fire, the flame pro-
duced by both being designed to perform the same work. Under this
arrangement there cannot possibly be any smoke even when bituminous
fuel is used, because no gases can escape complete combustion in the
opposing and consuming force of the blast, through which alone they

page_text: oan find egress from the fuel chamber. For this reason the same
arrangement is equally applicable to marine and stationary steam boilers,
the blast orifice of the fuel chamber being placed so that the flame shall
enter the fire-box of the boiler, the door of which must of course bc
kept shut to prevent the escape thence of the flame.
If a very wide flame is required the fuel chamber may be made wide
accordingly, with a wide transverse "slot" in the bottom as the blast
orifice; the nozzles of the blast pipes being set in apertures provided in a
refractory fire-clay or other suitable ridge block, rising slightly for that
purpose in front of the transverse "slot or opening.
"
As this arrangement of furnace must be worked by a forced blast the
escaping heat will not be required to create a draught in the chimney,
and it may therefore be made to give up its lieat as it passes away
to tubes through which the blast enters the furnace, thus producing a
hot blast.
.
When it is deemed desirable to provide for the production of a
reducing flame it will be necessary to arrange blast nozzles or pipes at
the back or sides of the bottom of the fuel chamber, in order that when-
the blast is turned on through these pipes it may have to force its way
through the bottom of the column of fuel in order to escape by the
orifice in front, which opens into the chamber or hearth in which the
licat is required.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said William Alexander Lyttle in the Great Seal
Patent Office on the 24th February 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ALEXANDER LYTTLE, of the Grove, Hammersmith, in the County of
Middlesex, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-seventh day of August, in the.
year of our Lord One thousand eight hundred and seventy-four, in the.
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said William Alexander Lyttle,

page_text: Her special licenee that I, the said William Alexander Lyttle, my
executors, administrators, and assigns, or such others as I, the said
William Alexander Lyttle, 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 FURNACES," upon the con-
dition (amongst others) that I, the said William Alexander Lyttle, my
executors or administrators, by an instrument in writing under my, or.
their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the
sanic was to be performed, and cause the same to be filed in the Great
Scal Patent Office within six calendar months next and immediately'
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Alexander Lyttle, 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:—
The object of this Invention is to apply to reverberatory and steam
boiler furnaces the same general principles of construction and action
which are observed in my Invention of the "duplex furnace " specified
in my Letters Patent, numberèd 749, and dated the 28th day of February
last, the title of which is "Improvements in the Means and Apparatus
for Smelting Iron," also to describe more fully the best means now
known to me for applying the principle of that furnace to the manu-
facture of iron or other metals.
In this duplex furnace there is an ore chamber in which the smelting
takes place, and at one or more sides of this ore chamber there are pro-
vided one or more separate fuel chambers communicating at their;
bottoms with the crucible of the ore chamber. These side chambers
are filled with fuel, and this fucl is consumed at the openings which
connect the fuel chambers with the ore chamber by the impact of a
blast which is directed against the bottom of the column of fuel at that
point. The fuel chamber or chambers being provided with an air-tight
trap or hopper on the top, the blast which strikes the fuel at the bottom
cannot escape upward through the fuel chamber, and hence any gases

page_text: or flame generated by the impact of the blast against the burning fuel at
the bottom are compelled to find vent from the bottom of the fuel
chamber backward against the blast by which they are produced. This
intermixture of the blast with the gases of combustion at a high tem-
perature causes the perfect combustion of the hydrocarbon gases evolved
in this furnace when bituminous coal is used. The course of these
gases is upward, thence through the contents of the ore chamber where
they supply the required smelting heat and carbonic oxide for reduction
of the ore.
It is obvious that under this arrangement the use of
bituminous coal whether in the form of lumps or dust can no longer be
objectionable for the smelting of metals, because its hydrocarbon gases
being perfectly consumed, where great heat exists and is required, can
no longer absorb and carry off heat by distillation from the reducing
zone of the furnace; whilst its tendency to become glued together into
masses by heat can cause no inconvenience for the reason herein-after
stated. Under this arrangement the
$6 burden" of the furnace or the
relation borne by the quantity of ore in the charge to the amount of
heat produced by the fuel will be under complete control, because the
rate of combustion, volume of reducing gas, and intensity of heat will
be capable of perfect adjustment at any moment by merely increasing
or diminishing the blast.
The same arrangement as regards the column of fuel or fuel chamber
with hot or cold blast can also be applied to ironfounders' cupolas, also.
to furnaces for the puddling of iron, whether fixed or rotary, and to all
other reverberatory furnaces of the ordinary type, more especially those
now required in the alkali manufacture. In order to adapt the principle
to such modifications it is only necessary to so arrange the blast orifice
of the fuel chamber as to ensure the issue and play of the flame and
heat exclusively into the chamber or hearth within which the heat is
required, and the only alteration will consist in the substitution of the
fuel chamber with its forced blast for the present fire-place.
If a very wide flame is required for a wide hearth or furnace the fuel-
chamber may be made wide accordingly, and of rectangular sectional
plan, with a correspondingly wide transverse "slot" in the bottom as
the blast orifice, the nozzles of the blast pipes being set in front of this
slot, as herein-after described and illustrated in Figure 3. Owing to
the circumstance that the combustion is due to the action of a forced
blast it is possible to abstract almost the whole of the heat from the

page_text: escaping waste gases of combustion by causing them to pass through a
multitubular water heater in order to heat the feed water of steam
boilers, and also to pass through a similar multitubular arrangement of
air heater for heating the air required for the aforesaid blast.
When it is deemed desirable to provide for the production of a
reducing flame it will be necessary to arrange blast nozzles or pipes at
the back or sides of the bottom of the fuel chamber, in order that when
the blast is turned on through these pipes it may have to force its way
through the bottom of the column of fuel in order to escape by the
orifice in front opening into the chamber or hearth in which the
'reducing flame is required.
Figure 1 represents a blast furnace arranged upon this principle with
two fuel chambers C, D, on opposite sides of the ore chamber A, B.
The latter communicates at or near the bottom of its crucible with the
fuel chamber C by the passage K, L, and it also communicates with the
fuel chamber D by a similar passage; Figure 2 represents this arrange-
ment in horizontal section in the plane of the blast nozzles I, K, L,
Figure 1, and as shewn by the forked arrows O, I, K, P, I, K.
I propose that a blast with two vent nozzles should be directed against
the bottom of the column of fuel in each fuel chamber at its two
opposite sides, each branch I and K of the fork having the same
diameter as tlie main pipe at O, P, Q, and R respectively. The ends or
nozzles of these blast pipes are set in an annular groove W, I, K, V,
Figure 2, and E, I, K, L, Figure 1; the depth of this groove being such
as to admit of the passage of blast all round the bottom of the column
of fuel. When the column of fuel is resting on the bottom of tho
fuel chamber, and filling the aforesaid annular groove one of the limbs
of each of the forks in this arrangement of pipes will be closed by fuel,
and one limb only will be in full action, but by reason of their direction
and the impact of their blast against the fuel, the latter will be cut
away by combustion until the inner nozzles of the fuel chamber are
cleared, when they will still further undermine the fuel. When once
the bottom of the fuel chamber has become red hot the fuel when of a
coking nature will always become coked for some distance above the
annular groove of the blast nozzles, and the cake of coke thus formed
will on being pressed down by the fuel resting upon it keep the annular
groove sufficiently clear thenceforward to admit of the more ready and
equal undermining of the fuel by the action of the blast.

page_text: Owing to the conical taper of the fuel chamber widening downwards
the fuel must come down against the bottom of the chamber when
undermined, because, as there is no passage of flame through the fuel,
the ring or cake of coke formed can only be at the bottom, and cannot
adhere to the sides with sufficient force over so small an area as to resist.
the crushing weight of the superincumbent column of fuel. In order to
prevent the passage of the blast upward through this chamber when
lump fuel is used any desired trap or valve may be employed for closing
it in the same way as blast furnaces are now closed after the introduction
of each charge of minerals when it is desired to divert and utilize tho:
escaping gases of the furnace. In Figure 1, F, G, H, represents a flat.
trapdoor carried by a lorrey mounted on four flanged wheels G, H,.
which run upon tram rails and serve to carry the trapdoor horizontally
away from the top of the fuel chamber when fuel is to be introduced.
The trap plate is raised or lowered from its bed by means of the vertical
screw and hand wheel F precisely like the screw which works the
common old railway break.
•
I do not show any special structural arrangement or lining of the
furnace nor any change in the construction or mode of setting the
nozzles of the blast, nor yet in the hearth, the hoist, or any other
accessory of the common blast furnace. Any desired arrangement may
be applied for the withdrawal of the escaping gases for utilization from
the top of the ore chamber A.
Additional nozzles may be set for the introduction of blast at any
other points around the bottom of the fuel chamber, but a hot blast may
if desired be used with the nozzles L, L', S, T, Figure 2; these nozzles
being intended to convey only such an amount of blast as will suffice
to consume the hydrocarbon gas of bituminous or gassy coal, and also to
create a more intense heat at the crucible of the furnace by wholly or
partially consuming there the carbonic oxide gas first formed in the
bottom of the fuel chamber.
Figure 3 represents the application of the same furnace principle to a
stationary steam boiler; Figure 4 shows a plan of Figure 3. in a hori-
zontal plane taken through F, Figure 3. S is the steam boiler and D, B,
Figures 3 and 4, is a branch water pipe leading out therefrom to the
bottom of the fuel chamber H, F. The blast pipe P, Figure 4, passes'
through this water pipe so as to be protected from the intense heat of
:

page_text: Thirdly. The use of such fuel chamber for pig-iron furnaces con-
structed without any contraction towards the bottom and without any
inclination of the inner sides of the chamber which would tend to throw
the fuel forward toward the crucible or hearth of the ore chamber, also
with a nearly flat bottom for the same purpose of creating no tendency
in the descending column of fuel to force its unconsumed fuel into
the hearth of the ore chamber.
Fourthly. The use of a high vertical fuel chamber with an opening at
one side of the bottom, into which a forced blast shall impinge and burn
away the fuel as and for the fire-place of the present ordinary puddling,
reverberatory, or steam boiler furnaces, whether moveable or stationary,
as herein-before described.
Fifthly. The use of the aforesaid arrangement of furnace as the means
of manufacturing pig iron in accordance with the Specification of any
of my various Letters Patent of last year for improvements in the
smelting of such iron:
In witness whereof, I, the said William Alexander Lyttle, have
hereunto set my hand and seal, this Twenty-fourth day of
February, in the year of our Lord 1875.