IMPROVEMENTS IN GRINDING COAL, IN PREPARING COAL FOR BURNING, IN SUPPLYING IT TO FURNACES, AND IN BURNING POWDERED COAL, ALSO IN APPARATUS TO BE USED FOR THESE PURPOSES
Year: 1868

page_text: LETTERS PATENT to Thomas Russell Crampton, of Great George
Street, Westminster, for the Invention of "IMPROVEMENTS IN GRINDING
COAL, IN PREPARING COAL FOR BURNING, IN SUPPLYING IT TO FURNACES, AND
IN BURNING POWDERED COAL, ALSO IN APPARATUS TO BE USED FOR THESE
PURPOSES."
Sealed the 9th February 1869, and dated the 13th August 1868.
PROVISIONAL SPECIFICATION left by the said Thomas Russell
Crampton at the Office of the Commissioners of Patents, with his
Petition, on the 13th August 1868.
I, THOMAS RUSSELL CRAMPTON, of Great George Street, Westminster,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN GRINDING COAL, IN PREPARING COAL FOR BURNING, IN SUPPLYING IT TO
FURNACES, AND IN BURNING POWDERED COAL, ALSO IN APPARATUB TO BE USED FOR
THESE PURPOSES," to be as follows:-
The first part of this Invention consists in grinding coal by means of
ordinary millstones in combination with an artificial current or blast of
air between the grinding surfaces produced either by a blast or a
[Price 8d.]

page_text: powerful exhaust acting as an inverted blast, or by blast and exhaust
combined, in order that the millstones may be kept cool and the coal
dust be blown from between the grinding surfaces as quickly as it is
reduced sufficiently fine; by this means a much larger quantity will
be ground by the millstones, and the sticking together of the bituminous
or damp particles of the coal, whether arising from the heat from
friction or otherwise, is prevented or much reduced. The exhausting
the dust or line particles so soon as formed may be used in any other
form of grinding whether by roller crushers or otherwise.
When an exhaust is employed for carrying off the dust of coal as it is
ground or produced the exhaust may carry it at once into a furnace to
be burnt. For burning coal 1 introduce it in the state of fine particles
or powder into a stream of air, and mix the air and fuel together before
burning, or introducing them into a combustion chamber as follows:-
When a fan is employed for producing the stream of air the proper
quantities of coal dust may be caused to enter the inlet of the fan
together with the air and be thoroughly mixed with, the air in the fan,
or where a stream of air is passing through a pipe or conduit to a
combustion chamber, being either forced or drawn through the pipe,
the requisite quantity of coal may be fed into the pipe at a distance
from the inlet to the furnace, the air carrying the coal with it, and the
requisite mixing may be effected by causing the current of air and coal
to impinge against fixed projections in the conduit, or the conduit may
be bent in various directions; the conduit may also in some cases be
turned slowly round on axes to prevent any deposit of coal. In order
also the more readily to enable fine particles of powdered coal to mix
intimately with a stream of air as it is supplied thereto 1 in some
cases cause the powdered coal to pass into the air conduit through
numerous small openings or passages ranged around the air conduit, or
the coal and air might be brought together in concentric rings for the
purpose of mixing them thoroughly together, as in order to obtain perfect
combustion rapidly it is essential that the coal and air should be. evenly
mixed together in definite quantities.
For measuring powdered coal and supplying it regularly to a stream
of air place the powdered fuel into a hopper, at the bottom of which
is a comparatively large opening by which the coal freely passes out on
to a table or surface at a short distance below the bottom of the hopper,
so that the space between the opening at the bottom of the hopper and

page_text: the table is always filled with fuel, and I employ an endless chain or
band of small buckets or other measuring apparatus to take measured or
fixed quantities of coal from the fuel which is resting on the table or
surface and to deliver them to the inlet of a fan or to a pipe or conduit
through which a stream of air is passing. An agitator or stirrer may be
placed in the hopper to keep the powdered coal from sticking. Or an
endless band having spikes standing out from it may be caused to travel
below the bottom or at any other convenient part of the hopper and
carry away from it an even stream of powdered coal, and when the
band afterwards passes around a roller the powdered coal will drop from
it into a funnel or hopper from which, it passes into the stream of air.
As the spiked band passes the hopper the spikes upon-it will be parallel
with one another, but when it passes around the roller the spikes open
outwards away from one another, as the spikes will then stand out
radially from the roller; this ensures the coal dropping sufficiently
regularly and evenly from off the band. The spikes upon the band might
also if desired be made to strike against springs or projections to assist in
shaking out the coal.. In some cases small. cups or indents.
attached to the band, A revolving drum having spikes around its outer
circumference may also be placed below the bottom of a hopper or in
other convenient position to carry off an even stream of coal therefrom.
The ends of the spikes may he brought in contact with a bar or other
suitable means, causing them to spring and shake out the dust or fine
particles. The projections on the endless band or roller may pass
through brushes or fixed spikes to clear out the coal. It is important
this should be effected particularly when the dust is damp, as then it
would be liable to clog.
:
may
be
When the measuring apparatus is to deliver the measured quantities
of coal to the inlet of the fan I form the measuring apparatus and the
fan into one machine, the framing or case of the fan and measuring
apparatus being made or connected together into one apparatus. When
a travelling or revolving measurer is employed as above described the
regulation of the measurer may be effected by a driving band working
over a pair of coned pulleys, friction surfaces, or otherwise; or a slide
may be slid immediately over the top of the spikes in such a manner as
to regulate the quantity of coal required.
I also combine together a measurer or feeder of coal and a grinding
apparatus with a fan or exhausting apparatus to draw away the ground

page_text: coal from the grinders and deliver it to be burnt so that the coal to be
burnt is measured to a grinding apparatus from which it is carried away
in the state of powder to be mixed with the requisite quantity of air and
burnt. If a fan is used it may draw the coal from the stones or grinders,
and any deficiency of air may be made up by admitting air into the
inlet of the fan or admitted or forced into the pipe between the fan and
the furnace or combustion chamber, or into the furnace, or by other
means. Or in place of this arrangement rough coal may be dropped
into a grinding apparatus and delivered when ground into a hopper, from
the bottom of which it is taken by a measuring apparatus as herein-
before described, to be mixed with air and burnt. By this arrangement
there may always be a reserve of fuel to keep up the fire should the
grinding apparatus be stopped for a time, the hopper being sufficiently
large for the reserve required. In those cases where two or more
furnaces are to be supplied with powdered coal and air I mix together
the air and coal at any convenient spot and conduct the combined air
and coal to the furnaces through a suitable pipe or conduit in much the
same manner as gas would be conveyed, each furnace having its own
communication with the main conduit fitted with a regulating valve, or
each furnace may have a separate pipe supplied with air and coal at or
near the place where they are mixed together. This mode of conveying
fuel to furnaces is especially of value where several boilers are ranged
in close proximity to one another as in steamboats and factories. Fixed
or revolving agitators may be placed at intervals along the conduit to
prevent the coal and air from separating, and where the coal has to be
conveyed long distances one or more fans may be applied to the conduit
to assist in forcing or drawing the air and coal through it. The air may
be heated previous to its being mixed with the coal, or after combining
or mixing air and coal together they may before they reach the com-
bustion chamber be caused to pass together through pipes or passages
filled with fire-clay balls, or it might be with brick or similar substances
heated, by preference, in the manner known as Siemens' regenerative
process, or the coal and air may both be heated and burnt in pipes
which are heated externally; in most cases however I prefer that the
combined fuel and air should be burnt in a combustion chamber.
In some cases I employ, as described in the Specification of a Patent
granted to Thomas Joseph Leigh on the 12th day of June 1866
(No. 1594), at the bottom of the combustion chamber a bath of metal

page_text: on to which jets of combined coal and air are caused to impinge in place
of feeding coal on to the bath of metal and directing jets of air upon
it, as described in the Specification above mentioned. Any number of
jets. or sheets of coal and air may also be caused to impinge one on
another in the furnace or combustion chamber.
In some cases I effect the combustion of powdered coal and air by
passing them through an ordinary fire resting on fire-bars, the jets of air
and coal being caused to rise up between the bars. The air and coal may
either be mixed together before they are allowed to enter the ash-pit
below the bars, or they may be mixed together in the ash-pit; jets of coal
and air may also at the same time be introduced above the fuel on the
fire-bars.
In some cases the coal and air may be caused to rise up or pass
between heated fire-bricks, or lumps, or balls, or other sufficiently
refractory material resting on ordinary fire-bars or bricks may be
formed into an arch, and other fuel may at the same time be burnt in
the ordinary manner on the top of the refractory material; or other
arrangements may be employed for effecting the combustion of air and
coal by injecting them between heated surfaces of fire-brick or refractory
material, and this is a very important feature of my Invention. These
heated surfaces will also assist to maintain an even heat in the
combustion chamber in addition to ensuring ignition.
When lighting the furnace these surfaces of refractory material must
he first heated before passing the coal and air through them. Steam,
superheated or otherwise, may be employed for conveying direct into the
furnace the powdered coal or powdered coal and air together so arranged
as to mix and distribute them or such portion of them as may be desired
on to refractory material placed in the furnace or into the furnace itself.
The mechanical apparatus employed for producing a combined stream
of air and coal may in some cases be arranged so that it may be worked
by hand as well as by other power, so that when lighting the fire for
getting up sufficient heat the apparatus may first be worked by hand.
In some
cases also the apparatus may first be worked by hand, or
otherwise until the natural draft of the furnace is sufficient for drawing
in the combined stream of air and coal, or as in locomotives until
sufficient draft is obtained by the exhaust or induced currents.
portion only of the air requisite for effecting combustion may be
employed for carrying the powdered fuel into a furnace, whilst the

page_text: remainder of the required quantity is supplied through other jets; or
the fine particles of powdered coal may be made to drop into a suitably
formed receptacle having agitators in it so that the air being drawn
through it may mix the coal and air before entering the furnace, or a
series of very fine holes, conical or otherwise, may be made in a plate
or plates so that the coal and air may pass into the combustion chamber
or furnace in very fine streams, which streams may be made to impinge
on each other by placing the holes at various angles or otherwise, this
may be applied without the use of a fan, simply allowing the ordinary
draft of the furnace to draw in the air and coal together, the quantity of
coal being regulated according to such draft.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Russell Crampton in the Great Seal Patent
Office on the 18th February 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME 1, THOMAS
RUSSELL CRAMPTON, of Great George Street, Westminster, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirteenth day of August, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Thomas Russell Crampton, Her special
licence that I, the said Thomas Russell Crampton, my executors,
administrators, and assigns, or such others as I, the said Thomas
Russell Crampton, 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 Inven-
tion for "IMPROVEMENTS IN GRINDING COAL, IN PREPARING COAL FOR BURNING,
IN SUPPLYING IT TO FURNACES, AND IN BURNING POWDERED COAL, ALSO
APPARATUS TO BE USED FOR THESE PURPOSES," upon the condition (amongst.
others) that I, the said Thomas Russell Crampton, my executors or ad-
ministrators, by an instrument in writing under my, or their, or one of
their hands and seals, should particularly describe and ascertain the

page_text: 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 Thomas Russell Crampton, do
hereby declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in
and by the following statement thereof, that is to say:-
The first part of this Invention consists in grinding coal by means of
ordinary millstones in combination with an artificial current or blast of
air between the grinding surfaces produced either by a blast or by a
powerful exhaust acting as an inverted blast, or by blast and exhaust
combined, in order that the millstones may be kept cool and the coal
dust be blown from between the grinding surfaces as quickly as it is
reduced sufficiently fine. By these means a much larger quantity will
be ground by the millstones, and the sticking together of the bituminous
or damp particles of the coal, whether arising from the heat from friction
or otherwise, is prevented or much reduced, and is effected as follows (sec
Figure 1, Sheet 1):-Coal is fed between rollers a to roughly crush it
when necessary; it then passes into the eye of the stone a', the valves
1 and 2 being closed; the exhaust fan b through its inlet draws air
through the pipe c from the eye of the stone and between the stones into
the stone case d; the lighter particles of coal then pass into the fan b,
which delivers them into the receptacle e where the dust deposits, the
air escaping through interstices in the cloth or in other material covering
the chamber, and the mass of the coal descending the shoot to sacks or
otherwise carried away. Where the blast or combination of exhaust and
blast is used a blast of air enters by means of a fan the eye of the stone a¹
to produce a current through the stones.
This blast apparatus is not
shown in the Drawings, but the system is so generally known in grinding
flour that it can be applied by any competent mechanic.
What I claim as respects this part of my Invention is grinding coal
by means of ordinary millstones in combination with an artificial current
or blast of air between the grinding surfaces, produced either by
a blast or powerful exhaust acting as an inverted blast and exhaust
combined: When an exhaust is employed for carrying off the dust of
coal as it is ground or produced the exhaust may carry it at once into a
furnace to be burnt; thus the valves (2, 3, and 4, Figure 1, Sheet !)

page_text: being closed the action is as follows:-The inlet of the exhausting fan.g
is communicated to the stone case d, the action of the fan drawing all
the produce of the grinding by the stones into it and delivering the same
into a pipe or conduit g', and forcing it to one or more furnaces to be
burned. Any deficiency of air passing through the stones may be made
up by openings in the stone case d' or into the inlet of the fan at 7.
Where a sufficient exhaust is produced by the furnace to draw the air
and coal from between the stones into the furnace such exhaust may be
applied for that purpose by the furnace being connected by a pipe to the
shoot h
What I claim as respects this part of my Invention is carrying off the
dust of coal as it is ground or produced by a grinding apparatus by means
of exhaust, and at once conveying it into a furnace or furnaces to be
burned, substantially as described. For burning coal 1 introduce it in a
state of fine particles or powder into a stream of air, and mix the air and
fuel together before burning or introducing them into a combustion
chamber in the following manner:-When a fan is employed for pro-
ducing the stream of air I cause the proper quantites of coal dust to
enter the inlet of the fan together with the air and be thoroughly mixed
with the air in the fan, the fan forcing it into a combustion chamber.
In Figures 3, 4, Sheet 1, is a hopper a-with stirring apparatus in
which coal dust is placed. Regulating slides or regulators b, b, are placed
between the hopper and cylinder d, covered with spikes e, the coal falling
between any required opening of the regulator on to the cylinder among
the spikes. The cylinder din revolving carries the coal from under the
hopper against fixed spikes, combs, scrapers, or brushes, revolving or
fixed, or the drum close to the hopper may be constantly jarred, which
effectually removes the dust (it being very liable to stick, particularly
when in a damp state), thereby insuring a regular stream of coal dust to
be detached from the cylinder d and fall into the hopper h which is in
connection with the inlet of the fan at i, the induced current of air of
the fan drawing the dust into the same, where by its action it is
intimately mixed with the desired proportion of air and forced from the
outlet of the fan i to the combustion chamber or furnace to be consumed.
Regulators may be attached to either the inlet or outlet of the fan to
regulate the quantity of the air; the coal and air may therefore by these
respective regulators be made to any required proportions. This coal-
measuring apparatus is combined with the fan in one machine arranged

page_text: Figure 11
to work by hand. The necessary drums and pullies for obtaining the
speed of fan required is shewn, an extra drum being provided so that
separate power may be applied to work the machine. The feeding
roller d being driven by the screw and worm-wheel motion seen at 7, the
stirrer, in the hopper is worked from the cylinder shaft by a band m, pitch
chain or cog wheels. Figures 7, 8, 10, shew grooved feed rollers of
various forms, also a plain roller, Fig. 9, either of which may be sub-
stituted for the spiked roller shewn in Figures 3 and 4.
shews the regulator of the feed to be a vertical.slide a which is slid before
an opening in the hopper to regulate the quantity of coal dust required.
As the hopper and the slide will touch the cylinder when the slide is shut
no feeding will take place. This vertical,slide may be applied to those
forms of grooves when the bottom of the slide can be formed of teetli to
correspond with the grooves in the rollers so as to fit into the roller when
the slide is closed and prevent feeding as the cylinder turns. Instead of
a cylinder an endless band with or without spikes attached to it may be
substituted to take the fuel from the hopper. The band a, Figure 12,
Sheet 1, passed over two rollers c, c, immediately under the hopper b
containing the coal dust, the quantity. of fuel being regulated by slides.
or by the same means as is done in the cylinder feeder.. In some cases,
an endless chain or band with small buckets attached or a vertical
revolving disc with buckets to the sides may be employed, but whatever
kind of feeder be used the dust should be forcibly displaced or disturbed
by shaking the measurer, or by combs, scrapers, springs, brushes, or
other means coming in contact with the measurer; and in those cases
where the surface of feeder is not even or smooth the interstices.
should be so constructed that the combs or disturbers may spring or
otherwise enter into them to displace the dust.
What I claim as respects this part of my Invention is supplying
furnaces or combustion chambers with a mixture of air and coal dust by
means of a fan, into the inlet of which coal dust is admitted in regulated
quantities.
Also the combination of a measurer of coal dust with a fan into one
machine, substantially as herein described, and for constructing apparatus
for measuring coal dust for the purpose of supplying it into furnaces
together with atmospheric air to be burned substantially in the manner
lierein described; that is to say, that the coal dust after being measured
shall be forcibly disturbed on or in the measurer by means of spring

page_text: scrapers, combs, brushes, or other convenient appliance coming in contact
with the measurer, or by shaking or jarring the measurer itself so as
to ensure a regular and continuous flow of dust from the measuring
apparatus.
Also I claim the combined arrangements of the apparatus herein
described for effecting that purpose.
I also according to my Invention combine together in one machine a
measurer or feeder of coal dust and a grinding apparatus with a fan or
exhausting apparatus. This I prefer to effect as follows, see Figures 1
and 2, Sheet 1, the valve 4 in the pipe c being closed the exhaust fan b
previously described is not used. Rough coal or slack is fed through a
shoot n by any ordinary shaking or other measurer into the hopper o,
where it is roughly crushed by the rollers a; or these rollers may act as
the measurer, the coal falling into the eye a' of the grinding stones p, p,
the exhaust fan g exhausting the stove case d through the pipe h (the
valve 1 in the pipe h, and the valve 4 in the pipe c being closed), the
coal dust upon being ground a certain portion of atmospheric air passes
with it through the pipe to the inlet of the fan where it meets other
air entering the fan at the opposite inlet h, over which inlet or other
convenient place is a valve (not shewn) to regulate the required quantity
of air. The fan then mixes the coal and air together and forces it through
the pipe g' which communicates to the combustion chamber to be burned,
or the coal dust may be sent into a chamber and deposited. In some
cases only a small portion of the ground coal may be drawn from the
stones through the pipe ¹ into the inlet of the fan g with the air which
has passed between the stones, the great bulk of coal being allowed to
fall through the pipe r (the valve 2 being opened) into. a reservoir or
hopper s, under which is a measurer t, through which the dust falls into
hopper into the inlet of the fan at u. The machine is driven from
a
the shaft by the means of belts as shewn. These driving arrangements
as well as the general disposition of the parts of the machine may be
varied to suit particular positions and circumstances. The hopper or
reservoirs may be made sufficiently large to serve as a reservoir of coal
dust in case the grinding apparatus or stones are not worked for a time
or from any other cause.
In supplying two or more furnäces or combustion chambers with mixed
air and coal dust it is effected in the following manner (see Figure 5,
Sheet 1) A fan a with a coal dust measurer not shewn is fixed close
to where the coal is ground or at any other convenient point, the proper

page_text: proportion of coal dust and air having entered the fan a is driven by it
through the main pipe b, and its branches c connecting with various
combustion chambers where heat is required, such as in generating steam,
heating puddling, blast, and other furnaces, regulating valves d being
placed at the junction of each branch with the main pipe b for regulating
the quantity to each furnace. These valves together with the valves for
regulating the coal dust and air into the fan will enable the workmen to
keep the proper proportions or mixture of air and coal dust to ensure a
perfect combustion; a pipe e with a valve in it connects the end of the
main b to the inlet of the fan which may be used to keep up a circulation
of the mixture if necessary. In this case the branches from the pipes f, f,
connecting with the before-mentioned branches c are not used. In some
cases it may be desirable to pass only a portion of the air with all the
coal dust through the far a, the remaining air being driven by the other
fan g connecting with its branches h to the air and coal dust branches c,
valves being placed at the junction of the branches. This arrangement
in some cases may be useful, as it will offer facilities for regulating the
mixture at each furnace by means of the valves k in the air pipe and
the valves & in the air and coal dust pipe; also this separate air pipe
may be connected to any portion of the combustion chambers desired
for supplying additional air thereto. In some cases a row of fans d,
Figure 6, corresponding to the number of furnaces required to be used,
may be placed in a line separately or on one line of shafting b, each fan
having an independent coal dust measurer or feeder and a pipe for
conveying the mixture of air and coal dust to its own furnace or com-
bustion chamber.
Figure 6 represents ten fans or apparatus arranged together, but the
number and relative position of the furnaces may be varied. When the
mixture has to be conveyed long distances in pipes, one or more fans
may be applied to the pipes to assist in conveying the air and coal dust
through them; agitators may also be applied at various parts of the pipes
if desired.
What I claim as respects this part of my Invention is the combining
of a measurer of coal with a grinding apparatus and a fan or exhausting
apparatus for the purpose of supplying combustion chambers with a
mixture of coal dust and air.
Also feeding or supplying a mixture of coal dust and air from one
common point or source to two or more combustion chambers much in

page_text: the same manner as gas may be conveyed, also the several arrangements
for effecting this object, substantially as described. . .
In some cases 1 supply measured quantities of coal dust into a stream
of air as it passes along a pipe into a furnace or combustion chamber to
be burned by allowing the current of air in the pipe to draw in the coal
dust together with some air through one or more coned or curved
openings. The coal dust and air may also be brought together in one
or more concentric rings or otherwise, and readily mixed together when
such current of air is sufliciently powerful; it is effected by placing the
curved pipe A, Figure 1, Sheet 2, into the main air pipe, B, coal dust
measured by the machine previously mentioned in this Specification; C
drops the coal dust into the wide part of the curved pipe A, and the
current of air in the pipe B inducing the coal dust with some external
air through the pipe A into the main pipe B, it there mixes and passes
to the combustion chamber.
When a suflicient current of air is passing in a pipe it may also be
accomplished in the following manner, Figure 2, Sheet 2:-The coned
end of a pipe A through which air passes is inserted into the coned end of
another pipe B, leaving a concentric or annular space e between them.
The coal dust dropping from a feeder D into the hopper the coal with
some external air is induced into the pipe B by the action of the stream
of air passing through the pipes as indicated by arrows, and then led to
the combustion chamber. This arrangement may be placed close to the
combustion chamber if desired.
Coal dust may also be made to enter the main pipe or may be directed
into a furnace by jets of fluid under pressure, using by preference com-
pressed air which may be heated or otherwise. This I prefer to effect as
follows: Figure 3, Sheet 2, A is a main pipe with only a Sinall pressure
of air passing through it. A higher pressure jet of air is forced through
the pipe B, which is placed in the coned pipe D; tlie feeder or measurer C
feeds the coal dust into the open part of the coned pipe D, the action of
the jet through B conveying the coal dust with some external air to the
main pipe A, and thence to the combustion chamber. When this high
pressure jet of air is used the feeder or measurer of coal dust may be
worked by a small air engine E supplied with air from the injection
pipe B, which is regulated by the valve F. The engine may be worked
by steam if desired. This arrangement of supplying air for working the
measuring apparatus attached to each furnace dispenses in some cases

page_text: with shafting being erected and connected to the furnaces for that
purpose, and it offers great facilities where many furnaces are distributed,
as the main pipe to feed the jet is easily communicated from the source
of the air supply to all the furnaces, whatever their position may be.
This injecting process may be used as above stated to send the air and
coal dust direct into the furnace or combustion chamber. Figure 4,
Sheet 2, A shows a furnace; B, the injecting pipe; C, the feeder which
may be worked by the small air engine before described, the injector
being as close as convenient to the furnace. A steam jet superheated or
otherwise may be used in some cases instead of the air jet; the jet of
steam will then induce the requisite quantity of air together with the
coal. The exact form and dimensions and the mode of regulating the jet
apparatus is not shewn, as that system is well known and can be pro-
portioned according to circumstances.
Where a draft into a furnace or combustion chamber whether produced
by the exhaust steam jet up the chimney or by any other means is
suflicient to take or induce the coal dust into the combustion chamber,
the arrangement is as follows:-The coal dust from the ineasurer A,
Figure 5, Sheet 2, drops into an open box B, through which the air is
drawn into the combustion chamber c. The dust and air may on its
passage be diverted by deflectors placed in the box B or be made to pass
through numerous small holes at D before entering the combustion
chamber, or other means may be adopted for mixing the air and coal
before or after entering the furnace or combustion chamber.
It should be observed that the air used may be either hot or cold
whenever deemed desirable, the hot air being heated by any of the well-
known means. In some cases the mass of air required may be heated
and conveyed to the combustion chamber in one pipe and the coal dust
mixed with a small quantity of cold air be conveyed in another and
injected or admitted into the hot air pipe or into the furnace in such a
position as to be readily mixed with the hot air as it enters the combustion
chamber.
What I claim as respects this part of my Invention is supplying coal
dust and air to a combustion chamber or to a pipe leading to a com-
bustion chamber by causing jets of air or steam under pressure to draw
the coal dust into the pipe or chamber, substantially as described.
I also claim drawing in powdered fuel together with air into a pipe or
main leading to a furnace or furnaces as herein described.

page_text: Also I claim mixing air and powdered coal by bringing them together
in concentric rings, substantially as herein described.
To make my Invention clear respecting the apparatus or chambers for
consuming powdered coal and the principles upon which they should be
constructed, I would observe that coal is ordinarily burned in mass placed
on fire-bars; the gases are first formed and then consumed so soon as the
proper admixture of air with the gas is accomplished. Owing to the
irregularity of the formation of the gases and the difficulty of supplying
air in the proper proportion to effect perfect combustion rapidly various
means are applied, such as dividing the air into fine streams, using
large fire chambers, and causing the gases to impinge on zig-zag flues,
and various other methods. In some cases when the gases alone are
obtained from the coal and collected into a separate receptacle it is more
easy to produce instantaneous combustion by simply directing the
proper proportions of gas and air into a heated chamber, causing them
to impinge into each other when perfect combustion would become
almost instantaneous, requiring no special means, such as zig-zag flues,
interstices, or great length of flue, to effect the object, consequently the
gas and air may be brought together close to any chamber requiring
practically a clean heat with no solid particles of carbon in it, and in
some cases into the chamber itself, where the heat is utilized. The
object of the present Invention is to burn solid fuel in even fine
particles, so as to have practically the same effect as in burning gas or
as nearly so as possible, viz., to consume all the gases to be obtained
from the coal, leaving practically no solid carbon to pass out of the
combustion chamber, as in some cases the pressure of solid carbon is
most prejudicial, particularly in connection with some of the heating
processes connected with iron working, and should be avoided. These
objects are attained by reducing the coal or coal slack into fine particles
and intimately mixing them with air, and consuming them in a com-
bustion chamber so constructed and arranged that the particles of coal
are retained in the combustion chamber for a sufficient length of time to
allow of their being entirely consumed. The manner in which this
chamber is constructed will vary according to the size of the particles
of coal to be consumed, and the sizes of the particles to which the
coal is reduced will be determined by their cost of production; and as
an example which bears particularly on this Invention if
we desire to
use the cheap refuse slack of coal usefully instead of the larger and

page_text: more expensive coal if the cost of reducing the slack to a given fineness
renders it more costly than the large coal the process would not be
from this point of view commercially advantageous and therefore useless.
It is quite possible by mechanical abrasion and carefully separating the
coal to make it almost an impalpable powder like soot or lampblack,
and if such almost impalpable coal powder be intimately mixed with
its proper proportion of air and injected into a hot closed fire-brick
chamber with an outlet for the consumed gases to escape would for all
practical purposes be consumed before leaving chamber (little solid
carbon issuing) very nearly as rapidly as gas and air would be burned,
but the cost of producing such impalpable powder would exceed the
difference in cost between the large coal and the 'slack, therefore the
'furnace should be so constructed to burn that fineness of coal which
can be commercially produced at a reasonable cost. Coal can be ground
in ordinary millstones within such limits of cost as mentioned but not to
that fineness. which can be practically consumed. in a small simple
chamber like gas or the impalpable coal dust before mentioned. And in
order to effectually consume such coal dust as can be produced at a
suitable price it is necessary that the mixture of air and coal dust should
during its passage through the heated chamber be consumed before
entering the position where the heat has to be neutralized, and this
I accomplish by employing a combustion chamber of larger dimensions,
or by causing the products of the-mixed. air and coal dust to pass in
a circuitous course through the combustion chamber either by forming
the combustion chamber with a zig-zag flue, or by placing within the
combustion, chamber brickwork built up with comparatively small
openings, say 4" x 4" between the bricks to cause the products in the
chamber to be baffled to the greatest possible extent; these flues or
openings cannot be. defined with precision, as it will depend upon
various circumstances, such as on the quality of the coal and refractory
material to produce slag, the better the quality of the coal and refractory
material for reducing the slag the smaller the openings may be and the
less space required for the furnace. Care should be taken in all cases to
so arrange the openings that the slag may collect at convenient points
and run out of the furnace through suitable openings or be removed
by hand when necessary. To facilitate the slag keeping in a fluid state
various known substances may be inserted into the furnace for that
object, and if desirable in a powdered state, together with the coal 'dust
and air.
It will be obvious where room is available small interstices

page_text: should be avoided, and such dimensions of flues used that they may be
readily repaired, but care should be taken, particularly where excessive
heats are required, as in melting, puddling, and other furnaces, not to
extend the flues more than possible, as the heat should be utilized as
near as convenient to where it is generated. It has been proposed to
place in the bottom of a combustion chamber material to form melted
cast iron or melted slag; separately or combined; the iron or slag
being first melted while blasts of air are directed into or amongst the
coal resting on the melted material for the purpose of consuming the
same. Instead of dropping coal on such melted mass and forcing
streams of air through it from one or more jets, I inject one or more
jets of a mixture of coal dust and air 'direct on or into the melted
máss referred to, which will insure an equal and rapid combustion of
the coal dust.. In some cases the mixture may be made to impinge
'direct on or into the flues or interstices of the brickwork.
Description of Combustion Chamber, see Sheet 2, Figure 6.-a is
a combustion chamber divided into two or more compartments, the
number being according to the dimensions of the coal dust used, .so
that all the products of the coal are consumed before leaving the end
compartment; b, c, is a pipe placed in any convenient position in the
chamber through which the mixed air and coal dust enter, and by
preference the mixture should strike the opposite side of the chamber
to the inlet; d are holes left in the brickwork, so that any superfluous
slag which may accumulate may run out or be taken out from time
to time; g is a moveable door for putting in fuel to heat up the
furnace before commencing work, which heating must be in all cases
effected. The action of the furnace is as follows:-The chamber being
heated the mixture of air and coal dust is blown through the pipe c,
striking the Bottom of the chamber, when ignition partially takes
place; it then returns, passing over the bridge or wall e down the
second compartment, under the wall f, and up the third compartment,
and into the chamber h, where the heat is or may be utilized.
Figure 9 shews a modification of the arrangement of furnace in
Figure 6.
In Figure 7, Sheet 2, the mixture as it passes into the
combustion chamber a strikes the bottom and passes through interstices
made in the brickwork b, where all the coal is consumed, then enters
the chamber, h to be utilized. The mixture of air and coal dust may
enter the combustion chamber by several jets or in wide thin streams,

page_text: Sheet 2, Figure 8. Instead of the interstices of brickwork being at
the end, as in Figure 7, they are at the top of the chamber, the air
and coal dust entering the chamber a by the pipe c passes up through
the interstices and thence to the utilizing chamber. It will be apparent
that from the form of the furnaces shown, together with the general
description, that they may be varied in form to suit almost all circum-
stances, whether applied to land, marine, or locomotive boilers or other-
wise; and I do not confine myself to any particular form of furnace
or combustion chamber so long as the general principles are maintained.
What I claim as respects this part of my Invention is the burning of
an admixture of atmospheric air and coal dust by passing them in a
zig-zag or circuitous course between heated surfaces of fire-brick or other
refractory material in a combustion chamber, so that the coal is
consumed before leaving such combustion chamber, substantially as
described.
I also claim the combined arrangements herein described of projecting
a mixture of air and powdered coal on or into a bath of metal or slag,
or both, which has been placed in the furnace for that purpose.
I also claim mixing coal that has been ground between horizontal
millstones with air and consuming such mixture in a combustion
chamber.
In witness whereof, I, the said Thomas Russell Crampton, have
hereunto set my hand and seal, this Twelfth day of February, in
the year of our Lord One thousand eight hundred and sixty-nine.
T. R. CRAMPTON. (L.S.)