An IMPROVED MODE OF AND APPARATUS FOR BURNING PULVERIZED FUEL
Year: 1871

page_text: LETTERS PATENT to Wilhelm Erdmann Albert Hartmann, of Swansea,
in the County of Glamorgan, (Engineer), for the Invention of "An
IMPROVED MODE OF AND APPARATUS FOR BURNING PULVERIZED FUEL."
Sealed the 26th March 1872, and dated the 9th October 1871.
PROVISIONAL SPECIFICATION left by the said Wilhelm Erdmann
Albert Hartmann at the Office of the Commissioners of Patents,
with his Petition, on the 9th October 1871.
I, WILHELM ERDMANN ALBERT HARTMANN, of Swansea, in the
County of Glamorgan (Engineer), do hereby declare the nature of the
said Invention for "AN IMPROVED MODE OF AND APPARATUS FOR BURNING
PULVERIZED FUEL," to be as follows :—
The object of this Invention is to utilize coal dust by burning the
same while in a disintegrated state in smelting and other furnaces.
To this end I fit the furnace with a hopper for the reception of the coal
dust and I regulate the discharge of the fuel therefrom by means of a
grooved roller or its equivalent, to which a slow motion is given. In
connection with the contracted discharge passage of this hopper is a feed
pipe which leads directly to a combustion chamber. Into this feed pipe

page_text: I throw a blast of air or a steam blast, or a mixture of the two. As the
fuel drops into this feed pipe it is met by the blast and carried forward
to the combustion chamber. In order to ensure the proper mingling of
the blast and fuel, and thereby prevent a deposit of the fuel in the
combustion chamber, I mount in the feed pipe near its exit end and
behind its last bend a spindle, which is in the line of the axis of the pipe,
and which spindle is provided with one or any number of oblique or
twisted blades in the manner of certain turbines or screw propellors. By
giving a rapid rotary motion to this turbine or screw I ensure an
intimate mixture of the blast with the fuel, and the better to attain this
end I fit the turbine or screw with a concentric conical shield at its rear
end, or I enlarge the boss of the turbine or screw and thereby cause the
outer and more effective part of the blades only to act on the passing
current. The motion for driving the grooved feed roller I sometimes
take from the turbine spindle, and I thus proportion the supply of 1
fuel to the speed of the mixing screw. This turbine may be driven
independently by gearing attached to its spindle, or take its motion from
the blast.
The furnaces to which this apparatus is to be adapted should have a
fire-place as usual, which on the starting of the furnace will require to
be used. When the furnace has attained a good heat the fire may be
damped by clay and sand and the upper part of the fire-place will then
form a combustion chamber suitable for the burning of the coal dust. The
coal as it is discharged into this heated chamber will become ignited, and
a continuous supply being kept up a rapid and fierce combustion will be
maintained. In some cases I propose instead of damping the fire to
build a combustion chamber above the fire-place and to connect the two
together by flues, which may be closed when the desired heat is obtained
for igniting the coal dust. If the furnace to be heated is very long, as
is the case with certain spelter furnaces, I employ more than one feed
pipe, by preference two, which I place at opposite ends of the furnace,
so that the streams of blast and fuel are injected horizontally and
parallel to the long sides of the furnace.
When applying the Invention to pot furnaces I discharge the blast
and fuel through pierced lumps, which severally support a pot, the fred;
pipe being fitted with a mixer screw at or near its extremity.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Wilhelm Erdmann Albert Hartmann.in the Great
Seal Patent Office on the 9th April 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILBELM
ERDMANN ALBERT HARTMANN, of Swansea, in the County of Glamorgan,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Ninth day of October, in the year of
our Lord One thousand eight hundred and seventy-one, in the thirty-fifth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Wilhelm Erdmann Albert Hartmann, Her
special licence that I, the said Wilhelm Erdmann Albert Hartmann,
my executors, administrators, and assigns, or such others as I, the said
Wilhelm Erdmann Albert Hartmann, 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 King-
dom of Great Britain and Ireland, the Channel Islands, and Isle of Man,
an Invention for "AN IMPROVED MODE OF AND APPARATUS FOR BURNING PUL-
VERIZED FUEL,” upon the condition (amongst others) that I, the said
Wilhelm Erdmann Albert Hartmann, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands
and scals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Wilhelm Erdmann Albert Hartmann,
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, reference being had to the Drawing
hereunto annexed and to the letters and figures marked thereon (that is
to say) :-
The object of this Invention is to utilize coal dust by burning the
same while in a disintegrated state in smelting and other furnaces. To
this end I fit the furnace with a hopper for the reception of the coal
.

page_text: dust, and I regulate the discharge of the fuel therefrom by means of a
grooved roller or its equivalent, to which a slow axial motion is given.
In connection with the contracted discharge passage of this hopper is a
feed pipe which leads directly to a combustion chamber. Into this feed
.pipe I throw a blast of air or a stream blast, or a mixture of the two.
As the fuel drops into this feed pipe it is met by the blast and carried
forward to the combustion chamber. In order to ensure the proper
mingling of the blast and fuel, and thereby prevent a deposit of the
fuel in the combustion chamber, I mount in the feed pipe near its
exit end and behind its last bend, a spindle which is in the line of 1
the axis of the pipe, and which spindle is fitted with a turbine or screw
propeller. By giving a rapid rotary motion to this turbine or screw I
ensure an intimate mixture of the blast with the fuel, and the better to
attain this end I fit the turbine or screw with a concentric conical
shield at its rear end, or I enlarge the boss of the turbing or screw, and
thereby cause the outer and more effective part of the blades only to act
on the passing current.
In the accompanying Drawing, Fig. 1 shows an elevation of the back
of the grate of an ordinary copper smelting furnace with my improved
apparatus applied thereto, and Fig. 2 is a partial sectional clevation
through A, B, Fig. 1. The blast or steam blast enters the apparatus
through the blast pipo a, a', at a, and issues through the blast nozzle a'
into the feed pipo b, b. At a¹ the blast becomes mixed with the dust
fuel, which drops through the funnel e on to the top of the blast nozzle.
The blast and fuel together are then carried through the feed pipe b, b,
and pass through its last bend c, c¹, into the combustion chamber. The
pipo c, c, is joined to b, b, by a screw clamp or similar means (not
shewn in the Drawing) so as to be readily removeable; it contains the
mixer, and is shewn on a larger scale at Fig. 3, Sheet II.
The fuel is contained in a conical hopper f, and is fed into a funnel e
by the grooved roller J.
The feeding arrangement is shown on an enlarged scale at Figures 5
and 6, Sheet II., Fig. 5 being a section taken parallel to the axis of
the feed roller, and Fig. 6 a section at right angles thereto.
As will be observed the roller 7 is surrounded on three sides by flat ¦
brushes of bristles or wire or similar material marked m, n, and n¹.´
The fourth side is formed by part of the brush framing 4, which here

page_text: nearly touches the roller, so that' no fuel can escape in that direction.
The brush n', Fig. 5, is fastened to a slide, so that the length of roller
which is feeding the fuel may be regulated as desired by shifting the
slide, or the bottom of the hopper may be closed by it altogether. The
5 roller is grooved by preference spirally. The spindle of the roller is
supported at or near its ends by suitable centres or bearings, and it
carries a worm wheel o, o, which gears with a worm 'p on the spindle q.
The manner of driving the roller will best bo scen by reference to
Figures 1 and 2. On the spindle q is fastened a single sheave or step-
sheaver (see also Figures 5 and 6), and this sheaver is driven by an
endless cord from the smaller sheave i secured to the end of the mixer
spindle. If a step sheave is used the speed of the roller 9 may be
increased or diminished by laying the cord in different grooves of the
same. The end of the feed pipe c, c', reaches an inch or two into the
› brickwork of the back of the grate, a hole being provided to receive it,
which hole opens conically towards the grate. Below the grate bars of
the combustion chamber is fitted an iron door h which swings on hinges,
and is intended to form a close bottom to the combustion chamber.
This door h is counterbalanced by weights k, which serve to retain it
when desired in a raised position.
The mode of starting the furnace is as follows:-The iron door / is
let down to the position shown in Figures 1 and 2, and the hole for the
feed pipe is luted up and a fire is then lighted on the grate bars n
through the usual fire-hole (not shewn in the Drawing). When the
6 furnace is hot the hole in the back of the grate is opened, the feed pipe
is introduced, and the blast and a little coal dust turned on. The
door is now closed and luted, and when the fire has nearly burnt down
the feed of dust coal is increased, and sand and clay is introduced
through the fire hole and door ø until a bottom is formed, as shewn in
Fig. 2. The slag formed runs off underneath the door v, where a
suitable channel is loft for it. 8, 8, are holes provided with plugs for
the admission of additional air or blast if required.
This furnace may also be started by making the sand bottom as
shown, but permanent, lighting a wood or coke fire on it and giving
some blast and coal dust (which for this purpose must be rich in gas)
until the furnace is hot, when the feeding of the pulverized fuel.
commences, but I prefer the former mode.

page_text: Figures 7 and 8 are clevations corresponding to Figures 1 and 2,
but the left hand half of Fig. 7 shows a section through C, D, of
Fig. 8.
As will be seen, the grate in this case is lowered, and a permanent
combustion chamber is built above it.
This furnace is worked as follows:-The feed pipe is removed, and
the hole plugged up, then a fire is lighted in the grate through a fire
hole (not shewn). The flame rises through the flue t, which extends
across the whole width of the grate, and passes through the combustion
chamber to the body of the furnace. When the combustion chamber
is sufficiently heated, the feed pipe is introduced and the blast and
coal turned on, and as soon as all is fairly at work the iron or clay
dampers wo, wo, are moved forward so as to close the flue t, and through
the door some sand and clay is thrown on them to level the bottom
and protect the dampers. The lower grate being now shut off from all
draught, the fire thereon is soon extinguished.
In Figures 2 and 8 the feed pipe is represented by dots in a second
position to shew that it may be varied to suit varying circumstances.
Thus, if for instance it is desired to keep the ashes from the charge
with great certainty, I introduce the feed through an opening in the
roof of the grate over the bridge (as indicated by the dotted lines);
or if the fuel is very combustible, I make the combustion chamber
shallower and put the feed pipe more horizontal or even quite horizontal,
at the same time lowering it several inches that the fuel may not strike
the roof of the grate and injure it.
Fig. 3 shows the pipe c, c', in longitudinal section. O is the spindle
of the mixer, and L is the mixer. The front end of this spindle is
supported by a pin forming part of a stand F secured to the pipe c, c';
and at the back the spindle rests on a similar pin G, which is screwed
to a bracket of the plate H, which latter plate serves to close the back a
of the pipe c, c', and can be removed for withdrawing the mixer when
required. The spindle carries at its front end the mixer L, shewn
detached at Fig. 4. The blades of the mixer I prefer to curvo helically,
and at the back and outside the pipo c, c', is the sheave i, from which
motion is transmitted to the feed apparatus. I is a tube surrounding a
the spindle C and carried by the plate II, and it extends as far inwards
as the mixing blades, where it opens to a conical shield K. When the

page_text: apparatus is in motion its action is such as to cause an influx of cold air
through the tube I, thus keeping the spindle O, C, cool. The pitch and
number of the blades of the mixer will be subject to.variation according
to the pressure of blast and the power required for driving the fuel
feeder. For a full size copper furnace, for instance, I usually employ
a feed pipe of from four to five inches bore, and a mixer with three or
six blades of a pitch similar to that shewn in Fig. 3.

page_text: Secondly. The means above described with reference to the Drawings
for facilitating the ignition and burning of the pulverized fuel in the
combustion chamber.
In witness whereof, I, the said Wilhelm Erdmann Albert Hartmann,
have hereunto set my hand and seal, the Fifth day of April, 5
in the year of our Lord One thousand eight hundred and seventy-