Improvements in and relating to Apparatus for and Method of Burning Coal Dust or other Granulated or Powdered Fuel.
Year: 1894

page_text: Date of Application, 18th Dec., 1894-Accepted, 19th Jan., 1895
COMPLETE SPECIFICATION.
Improvements in and relating to Apparatus for and Method of
Burning Coal Dust or other Granulated or Powdered Fuel.
I, COLIN WILLIAM CLAYBOURNE, a citizen of the United States of America,
residing at No. 948 North New Jersey Street, in the City of Indianapolis, County
of Marion and State of Indiana, one of the United States of America Gentleman,
do hereby declare the nature of this invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:-
Figure 1 shows a perspective view of my apparatus, with positive fuel feed
device:
Figure 2, a view of a longitudinal vertical section of the same, and
Figure 3 a view of a longitudinal vertical section of my apparatus as arranged
for use without the feed screw.
Letters of like name and kind refer to like parts in each of the figures.
The object of my invention has been to provide improved means for and process
of burning coal-dust, or other granulated or powdered fuel, and to this end my
invention consists in the apparatus and in the process, as hereinafter described.
In the means, as heretofore used, for burning coal-dust and the like, the
pulverized or granular fuel has been fed into the fire-box, to be there met by an
air-blast to blow it forward and supply the oxygen for its combustion.
In my present apparatus and by the process as covered by the present case, I
make certain of the thorough separation of the particles of fuel, and their intimate
mixture with a gaseous fluid containing oxygen, before they reach the fire-box or
combustion-chamber, so that they will flash into flame and be completely ignited,
immediately upon entering the fire-box or combustion-chamber, and will produce a
very hot, clear, smokeless flame, capable of being directed or guided, by any
Buitable draft device, so that it will apply its heat uniformly and evenly over any
surfaces to be heated, without any blast or blow-pipe action, which, as is known, is
destructive to the sheets or tubes of boilers, on account of the flame necessarily
striking more directly and forcibly on one part than on another of the surface to be
heated.
In the drawings, A designates a body, which, in general outline, is cylindrical,
but can be of any other shape, as desired. Through such body passes the large
central passage a for the admission of the coal dust or other pulverized or
granulated fuel, and the passage a¹ for the steam, air, or other gaseous fluid, below
the fuel passage, and having its discharge mouth much smaller than that of the
latter.
On the body, below the lower passage, is the deflector a', extending forward and
upward at an angle to the line of a jet issuing from the passage a'.
As shown in the drawings, this deflector is preferably, though not necessarily,
curved or concave, instead of being straight.
Connected with the rear or outer end of passage a is the feed-tube a³, communi-
cating at its outer end with the hopper B, or other source of supply of coal-dust,
saw-dust, or other granular or pulverized fuel to be burned.
As shown in the drawings, the discharge end of passage a is continued out beyond
the front face of body A within a projecting tubular boss, so that its mouth is a
short distance forward of the end of the passage a', and at its front end such boss
is cut away on a plane extending downward and rearward.

page_text: In the form of apparatus shown in Figures 1 and 2, there is within tube a³, the
revolving conveyor screw a' which, receiving the fuel from the hopper B, carries
the same forward towards the mouth of passage a, at a rate depending upon the
speed of rotation of the screw. At its rear end, the screw-shaft a passes out
through a suitable bearing in the plug a, screwed into the outer end of the tube,
and is provided beyond such plug with a pulley or wheel a', which is to be
connected with and driven from any desired motor or source of power by means of
a belt or other suitable connecting gearing. This screw form of feed is only shown
and described as one form of a number of conveying devices, which might be used
for the same purpose, and I do not limit myself to the use of it in my apparatus.
The coal-dust, saw-dust, or other pulverized or granular fuel might be fed by
gravity, or in any other way instead, without departure from my invention.
as
Where the fuel feed passage is continued out beyond the mouth of passage a³,
shown in the drawings, I have found that the pulverized or granular fuel will, when
dry, be drawn freely and rapidly enough from the hopper, along the tube a³, without
the use of the conveyor screw, by the action of steam admitted into the bulb to be
described, through passage a', as hereinafter set forth.
When the fuel is to be thus drawn in, without the use of a positive feed device,
I employ the construction of apparatus shown in Figure 3, having the feed tube a
with its outer or rear end extending beyond the point where the fuel enters from
the hopper B, or other source of supply of fuel, left open.
The passage of the fuel into said tube is to be so regulated that the latter will be
only partially filled, as indicated in the drawings.
The steam issuing from passage a¹, and passing by the projecting tubular boss
forming the forward continuation of the feed conduit or passage, will induce a
current of air through tube a³, which will draw the pulverized or granular fuel
rapidly along the latter and carry it from the same out of the mouth of the fuel
passage in head A, so that the fuel feeding will be continuous as long as the tube a³
is kept supplied from the hopper, or other source of supply.
If desired, the outer or rear end of the fuel tube as can be supplied with an air
receiving and directing funnel, as indicated in dotted lines in Figure 3.
The same feeding of the granular or pulverized fuel without the intervention of
a feed screw, or other positive feed device, could be secured if the outer end of
tube a³, beyond the hopper B, were closed, and the fuel were fed into the hopper
so as not to entirely close up the passage from it into said tube. The induced
current, caused by the action of the steam, and acting to convey the fuel, could
then pass down through the hopper itself, drawing the fuel therefrom. Passage a
is, through valved pipe a, to be connected with any suitable source of supply of
which
steam, air, or other gaseous fluid under pressure. Such source of supply,
can be of any desired form, is indicated in a conventional way only, at C.
The bulb D, herein before referred to, which is attached to body A, preferably,
but not necessarily, by being screwed thereon, as shown, has an interior chamber
which expands abruptly forward from around the space into which passages a and a¹
discharge, and then contracts again to the discharge neck d, having an orifice or
mouth preferably several times the size of passage a¹.
The general shape of the bulb is that of an oblate spheroid, or a sphere somewhat
flattened on its front and rear sides, with a conical or taper portion ou its outer side
running to the neck d.
In practice I have found very good results to be secured with the mouth of fuel
passage a one-half an inch in diameter, and the largest diameter of the interior of
the bulb, seven inches. The mouth of neck & was then about an inch wide.
I do not, however, intend to limit myself to such relative proportions, as the sizes
of passage a, bulb D), and mouth of neck d, can be departed from or varied at will,
without departure from my invention.
By practice it has been found that within certain limits, the horse power
producing capacity of my burner, as used on boilers, can be increased by increasing
the size of the steam opening and discharge mouth of the bulb.

page_text: If desired, in order to secure more rapid and easy feed of the fuel, the passage a
could be made larger, but if it is, it would be best to enlarge the opening through
neck d correspondingly.
As indicated herein before, I contemplate forcing in through passage a¹, either
steam or compressed air, or other gaseous fluid under pressure, sufficient to separate
the particles of fuel fed in through passage a, and whirl them about within the bulb,
so that they will be not only completely separated, but well and intimately mixed
with the steam or gaseous fluid.
Practice has shown steam to be not only economical, but to secure the best
results in the proper separation of the fuel particles, and the production of a large
volume of clear flame of the strongest heating power.
Whether steam, air, or other gaseous fluid is used, the pressure on the same need
not be so great as to force the mingled particles of fuel and fluid from the neck d,
so as to produce a blow-pipe form of flame, but can be, and is best kept low, so
that the flame while an exceedingly hot and smokeless one, of great volume, can be
drawn or directed by suitable draft devices to apply its heat uniformly over the
surface or surfaces to be heated.
With the apparatus constructed as shown and described, and the coal dust or
other pulverized fuel being fed in through passage a, and steam forced in through
the smaller passage a', the steam will, as it issues from the latter passage and
expands suddenly within the large chamber in the bulb, strike the fuel descending
towards the deflector a² and, being guided upward and forward by the curved
inclined face of the latter, will separate the fuel particles from each other, and
whirling them around with it within the bulb chamber, will be mixed thoroughly
and uniformly with them before passing on out through neck d.
The result is, that a mixture is produced which immediately upon issuing from
neck d, will take fire instantly and completely with each particle of the pulverized
fuel entirely ignited.
When the pulverized or granular fuel is dry, and the passage a is carried forward
of the mouth of steam passage a¹, as shown in the drawings, the steam passing
forward and upward past the mouth of the former passage, will produce a draft
which will, as indicated herein before, draw said fuel from the hopper through the
feed tube a³ and passage a, with sufficient rapidity, without any screw or other
positive feed device placed in such tube.
The flame produced by my burner upon ignition of the mixture issuing from the
mouth of the bulb, is clear and perfectly smokeless, and, because of the oxygen
and hydrogen of the steam being consumed in it, is an exceedingly hot one.
With low pressure on the steam, the flame produced is a soft one, easily directed
or guided by ordinary draft devices, so that its heat can be applied uniformly over
the surfaces to be heated, a most desirable feature where boilers, brick kilns or
lime kilns are to be heated.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In an apparatus for burning coal dust, or other granular or pulverized fuel, in
combination with a conduit and a source of supply of the granular or pulverized
fuel feeding into such conduit, an enlarged mixing chamber into which the conduit
discharges having a suitable discharge mouth, a source of supply of steam, and a
conduit for the same discharging into the mixing chamber past the mouth of the
fuel passage, substantially as and for the purpose specified.
2. In an apparatus for burning coal-dust or other granular or pulverized fuel, in
combination with the enlarged mixing chamber having a suitable discharge mouth,
a steam jet entering such chamber, and the feed conduit connected with a source of
supply of the fuel, and having its forward end projecting into the chamber, to a
point forward of the discharge mouth of the steam passage, substantially as and for
the purpose shown and described.

page_text: 3. In an apparatus for burning coal-dust, or other pulverized or granular fuel, in
combination with a conduit, a source of supply of the granular or pulverized fuel,
and means for feeding the same through the conduit, an enlarged mixing chamber
into which the fuel is discharged, having a suitable discharge mouth, a source of
supply of fluid under pressure, and a conduit for the same entering the chamber so
that the fluid will come in contact with the fuel entering the chamber and mingle
with the same, substantially as and for the purpose specified.
4. In an apparatus for burning coal-dust, or other pulverized or granular fuel, in
combination with a conduit, and means for supplying and feeding the pulverized or
granular fuel through the same, a second conduit connected with a source of supply
of fluid under pressure, an enlarged mixing chamber around the place where the
two conduits discharge, having a suitable discharge mouth, and the deflector
extending at an angle forward and inward across the path of the jet entering
through the fluid conduit and towards a line through the fuel conduit, substantially
as and for the purpose shown.
5. In an apparatus for burning coal-dust, or other pulverized or granular fuel, in
combination with a conduit and means for supplying and feeding the pulverized or
granular fuel through the same, a second conduit connected with a source of supply
of fluid, under pressure, a bulb surrounding the place where such conduits
discharge, having its interior chamber expanding suddenly forward, and then
contracted down to a smaller discharge mouth, and a deflector to direct the fluid
entering the chamber forward and inward at an angle to a line through the fuel
conduit, substantially as and for the purpose set forth.
6. In an apparatus for burning coal-dust, or other pulverized or granular fuel, in
combination with a source of supply of such fuel, and means for feeding the latter
from the same, a conduit through which the fuel is fed, a second conduit con-
nected with a source of supply of steam, and a bulb having an enlarged chamber
into which the fuel and steam conduits discharge, and within which the steam and
fuel are mingled together, and a reduced discharge opening, substantially as and for
the purpose described.
7. In an apparatus for burning coal-dust, or other granular fuel, in combination
with the enlarged mixing chamber having a suitable discharge mouth, a passage
for steam into said chamber, the fuel conduit extended into the same with its
discharge end inclining rearward and downward, and a deflector adjacent to the
mouth of the steam passage to guide the steam past the inclined end of the fuel
conduit, substantially as and for the purpose shown.
8. The improved process of burning coal-dust or other pulverized or granular
fuel, which consists in feeding such fuel into an enlarged chamber with a suitable
discharge opening, and bringing into contact with it as it enters such a chamber, an
expansible fluid under pressure, to separate the particles of fuel and whirl them
around with the fluid within the chamber before they reach and pass from the
discharge opening, substantially as and for the purpose specified.
Dated this 18th day of December 1801.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.