Improvements in or relating to Furnaces and in Steam Boilers used in Connection therewith.
Year: 1897

page_text: Date of Application, 29th June, 1897-Accepted, 12th Feb.,
1898
COMPLETE SPECIFICATION.
Improvements in or relating to Furnaces and in Steam Boilers used
in Connection therewith.
(A communication from BERNARD CORNELIUS HEAVEY and SAMUEL TAGGART
WHITE, of Chicago, Illinois, in the United States of America.)
I, ALFRED JULIUS BOULT, of 111 Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:
This invention relates to improvement in boiler furnaces generally, though it
relates more especially to boiler furnaces adapted to burn fuel dust, such as pul-
verized coal. The object is to provide certain improvements in the construction
of the fire-chamber, to the end of economizing in fuel consumption and increasing
the steam production.
In the drawings
Figure 1 is a broken longitudinal section on line 1 of Fig. 2 showing the
improvements applied to the furnace of a horizontal steam boiler; Fig. 2, a broken
plan section taken upon the irregular line 2 of Fig. 1; and Fig. 3, a vertical cross
section taken on line 3 of Fig. 1, and viewed in the direction of the arrow.
A is the front wall of the furnace having a door leading to the fire-chamber C.
A is the front wall of the boiler chamber; A3 A3 the side walls of the furnace;
A³ the rear wall thereof; and A the bridge wall. B is the grate. The furnace
projects forward of the front wall A' and is provided with a top wall A5. The
walls of the furnace are constructed of suitable brick, and the front, top and
side walls for some distance back are provided with an embedded casing r of non-
heat-conducting material, such as asbestos, or other suitable substance. The inner
side walls of the fire-chamber are preferably formed with vertical corrugations,
and the top wall is corrugated longitudinally, all to the end of increasing the
radiating surfaces, though the invention is not limited to the use of corrugated
walls. The grate B₁ consists preferably of the closely adjacent parallel and
longitudinally extending metal bars q surmounted by a series of supplemental
grate bars 9 of fire-clay, or the like refractory material, tapering along their
upper edges and provided with lateral shoulders which rest upon adjacent bars q.
The supplemental grate bars thus close every second opening between bars g and
shield said bars from the direct action of the incandescent fuel in the fire-
chamber.
rear
D is a frame consisting of four vertical manifolds connected through
side pipes p and front and cross pipes p². Extending between
the front and rear cross pipes is a horizontal series of pipes p³.
The frame of pipes D extends from the rear end of the top wall A5
to the bridge wall A It inclines slightly downward in the backward
direction and its top is close to the under side of the boiler E. The forward
manifolds connect through two pipes p' with the forward end of the boiler E;

page_text: and the rear manifolds ? connect through with the rear end of the boiler E.
Water in the boiler E will pass downward through the pipes p to the frame D, cir-
culate through the latter, become heated and rise into the front end of the boiler.
Thus a constant circulation is maintained.
"
...
Fitting upon the circulating pipes 23 are blocks F of fire-clay, or other refractory
material, which are placed at intervals, or spaced, as indicated in Fig. 2, leaving
a series of outlets through the frame D below the surface of the boiler E. The
hot products, of combustion from the fire-chamber C pass between the pipes, forming
the frame D, and the spaces n, thence backward over the bridge wall Athence
forward through the flues of the boiler E, whence they escape to the chimney G.
The water circulating from the boiler to the frame D is heated to a high temperature
and the blocks F form a heat storage bed beneath the boiler E.
As before stated, the fire-chamber is constructed more especially for burning.
fuel dust, which may be pulverized coal, or the coal dust which accumulates at
mines, and has hitherto been considered more or less worthless for fuel. The
fuel dust falls from a hopper, or chamber through, branch,tubes m to mixing
chambers H in the wall A. Steam blast-pipes i extend into the mixing chambers H,
and as the fuel dust falls through the tubes m it is sprayed backward into the
fire-chamber. The forward part of the fire-chamber forms heat storage walls which
soon after the furnace has been started so concentrate the heat that the fuel
ignites almost instantly upon entering the chamber and approximately perfect
combustion takes place. The frame D tends to retard the egress of the hot
products of combustion whereby it aids in producing perfect combustion in the
chamber and becomes itself very liot. The water circulating through the frame
is rapidly heated, and the blocks I form an incandescent bed beneath the forward
part of the boiler. All this tends to rapid steam-production.
While it is preferred to construct the improvements in every way as shown and
described they may be modified in the matter of details without departing from
the spirit of the invention as defined by the claims.
Having now particularly described and ascertained the nature of the said
invention as communicated to me by my foreign correspondents and in what
manner the same is to be performed, I declare that what I claim is :—
1. In a boiler furnace, the combination of a fire-chamber provided along its
forward portion with heat storage sides and top, the top terminating beneath the
forward end-portion of the boiler, a bridge wall at the rear end of the fire-chamber,
water circulating conduits extending from the rear end of said top to the bridge
wall, and spaced blocks resting upon the said conduits, substantially as and for the
purpose set forth.
2. In a boiler furnace, the combination of a fire-chamber provided along its for-
ward portion with corrugated heat storing sides, the top terminating beneath the
forward end-portion of the boiler, a bridge wall at the rear end of the fire-chamber,
water circulating conduits extending from the rear end of said top to tho
bridge wall, and spaced blocks resting upon the said conduits, substantially as
and for the purpose set forth.
3. In a boiler furnace, the combination of a fire-chamber provided along its
forward portion with heat storing sides and ton, the top terminating beneath the
forward end portion of the boiler, a fuel dust feeder and spraying device in the front
part of the fire-chamber, a bridge wall at the rear end of the fire-chamber, water
circulating conduits extending from the rear end of said top to the bridge wall,
and spaced blocks resting upon the said conduits, substantially as and for the
purpose set forth..
4. In a boiler furnace, the combination of a fire-chamber provided along 'its
forward portion with heat storing sides, the top terminating. beneath the forward
end portion of the boiler, a bridge wall at the rear end of the fire-chamber, a frame
formed of manifolds and water circulating pipes communicating with opposite
ends of the boiler and extending from the rear end' of said top to the bridge wall,
:

page_text: and a fuel dust feeding and spraying device in the front part of the fire-chamber,
substantially as and for the purpose set forth.
5. In a boiler furnace, the combination of a fire-chamber provided along its
forward portion with heat storing sides, the top terminating beneath the forward
end portion of the boiler, a bridge wall at the rear end of the fire-chamber, a frame
formed of manifolds and water circulating pipes communicating with opposite ends
of the boiler and extending from the rear end of the said top to the bridge wall,,
and spaced blocks of fire-clay, or the like, resting upon the said circulating pipes,
substantially as and for the purpose set forth.
Dated this 18th day of November 1897.
BOULT & WADE,
Agents for the Applicant.

page_text: Date of Application, 29th June, 1897-Accepted, 12th Feb., 1898
Improvements in or relating to Steam Boiler and other Furnaces.
(A communication from BERNARD CORNELIUS HEAVEY and SAMUEL TAGGART
WHITE, of Chicago, Illinois, in the United States of America.)
I, ALFRED JULIUS BOULT, of 111 Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
'
This invention relates to improvement in furnaces for burning fuel dust, such
as pulverized coal. The object is, first, to provide certain improvements in the
construction of the interior or fire-chamber portion of the furnace to give thereto
high heat storage capacity; and, second, to provide improved means for
automatically feeding fuel dust to the fire-chamber.
In the drawings
Figure 1 is a broken longitudinal section showing the improvements applied
to the furnace of a horizontal steam boiler; Fig. 2, a broken section taken on
line 2 of Fig. 1; Fig. 3, a broken view partly in section and partly in elevation
of an automatic fuel dust feeder constructed for a battery of furnaces; Fig. 4, a
broken front elevation on a reduced scale; and Fig. 5, a broken plan section
taken on line 5 of Fig. 1.
A is the front wall of a furnace having a door t leading to the ash-pit B, and a
door s leading to the fire-chamber C. A is the front wall of the boiler-chamber;
A3 A3 the side walls of the furnace A³ the rear wall thereof; and A' the bridge
wall. B is the grate. The furnace projects forward of the front wall A', and is
provided with a top wall A³. The walls of the furnace are constructed of suitable
brick, and the front, top and side-walls for some distance back are provided with
an-embedded' casing r of non heat conducting material, such as asbestos, or other
suitable substance. The inner sides of the fire-chamber are preferably formed
with vertical corrugations, and the top wall is corrugated longitudinally, all to
the end of increasing the radiating surfaces, though the invention is not limited'
to the use of corrugated walls. The grate B₁ consists preferably of the closely
adjacent parallel and longitudinally extending metal bars q, surmounted by a
series of supplemental grate bars 21, of fire-clay or the like refractory material;
tapering along their upper edges and provided with lateral shoulders which
rest upon adjacent bars q. The supplemental grate bars thus close every second
opening between bars q and shield said bars from the direct action of the incan-
descent fuel in the fire-chamber.
Extending through the front wall A above the doors are, preferably, two
converging and slightly inclined chutes or deflectors H. Above the said wall is a
coal dust receiving tube or hopper m, from the lower end of which extend branch-
tubes m terminating in the furnace wall above the deflectors H. In the sides
of the tubes are air inlet openings m³. Extending through the front A into the
spaces above the deflectors, and terminating at points more or less forward of
the tubes m³, are blast-pipes i communicating with a steam supplier which may

page_text: be the boiler E. The chutes or deflectors H form flaring mixing chambers opening
into the fire-chamber, the feed-tubes m' entering the tops between the blast-pipes
and fire-chamber. By preference the deflectors converge at an angle in the
horizontal plane, the apex of the angle being a point about midway between the
front and rear ends of the fire-chamber.
In order that a battery of furnaces may be fed uniformly from the same fuel
dust supplier the feeding mechanism shown in Fig. 3 is provided. A tube or
conduit extends from a storage bin or fuel pile, not shown, to a supply-chamber A.
In the tube is a conveyer screw.
Above the chamber is a chamber to which
extends a conveyer tube The, construction, is such that if more coal dust is
elevated from the chamber to the chamber than is carried off, the overflow
will fall through a passage back to the chamber . Extending from the
chamber is a conveyer tube 15, communicating with hoppers or distributing
receptacles, one in front of each of the furnaces to be fed. At the end of the
tube is a downward extending tube extending to an overflow receptacle, from
the base of which extends a conveyer-tube8 back to the chamber. At each
receptacle or hopper is a conveyer-tube extending to the top of a receiving
tube m of a furnace. The conveyer screws in the tubes are rotated by belts, not
shown, at desired speed, which may be varied at will. Coal dust conveyed through
the tube to the supply-chamber is elevated to the chamber, from which it is
conveyed through the tube to the distributing hoppers k. The latter hoppers
are thus kept filled, any overflow passing to the tube and overflow receptacle
whence it is conveyed luck to the receptacle through the tube. The constant
agitation given to the fuel dust prevents it becoming packed: From the hopper k
opposite the furnace the fuel dust is conveyed through the respective tube A to
the receiving tube m of the furnace, whence it falls downward through the branch
tubes m to the deflectors or mixing chambers H.
In operation, the fire is started upon the grate B' and' initially fed with fuel
through the doors until the fire-chamber is thoroughly heated, and an incan-
descent bed of fuel covers the grate. The conveyer screws are then set in operation
and steam is turned in through the blast-pipes i. The coal dust which descends
through the branch feed-tubes m¹ falls into the mixing chambers H and is sprayed
by, the steam jets backward into the fire-chamber C.
In feeding, coal dust to a furnace it is desirable that the amount fed shall be
properly proportioned, so that it will enter the fire-chamber as fast as but no
faster than it can be consumed. If it is not fed fast enough the desired heat
production cannot be maintained, and if fed too fast perfect combustion will not
take place and more or less unconsumed fuel will be carried by the draft over-
the bridge wall. To produce the best results the fuel must be prevented from
caking or entering the furnace in lumps. The conveyer screws have a tendency
to grind the coal dust and keep it from caking, though if fed directly by a screw
into the furnace the coal dust will be more or less packed and prevent even dis-
tribution. In the present construction the coal dust drops into the branch-tubes m¹
becoming disintegrated as it strikes the walls of the tubes and falls in the form of
spray in front of the mouths of the blast-pipes. The mouths of the blast-pipes
may be as wide as the lower ends of the feed-tubes, so that all the dust as it falls
will be sprayed evenly into the fire-chamber. In practice there is an opening,
of small area, about each blast-pipe through which a limited quantity of air
will enter, but most of the air to support combustion enters through the open-
ings me in the feed-tubes.
One of the great advantages of this construction lies in the fact that no coal
dust can lodge in any part of the mixing chambers H or in the feed-tubes m¹.
These parts may become very hot and the dust being more or less explosive some
danger would attend the use of dust were it permitted to lodge and collect in the
feed-tubes or mixing chambers. The forward part of the fire-chamber being more
or less close affords a heat storage chamber, its heat storage properties being
enhanced by the non-heat conducting casing r, and its radiating properties being

page_text: enhanced by the increased' surfaces afforded by the corrugated walls. Thus in
practice the heat at the forward end of the furnace becomes so intense that the
fuel ignites almost immediately upon entering the chamber, and the streams
playing backward from the deflectors appear incandescent. Combustion of the
fuel is increased by causing the incoming steams to meet at about the center of
the furnace, where the particles of the fuel strike against each other, intermix
and thus become thoroughly disintegrated. Air to supply combustion also enters
from the ash-pit through the grate bars. With the construction described but
little judgment is required on the part of an operator to maintain just the right.
supply of fuel to effect such perfect combustion that practically no unconsumed
particles of fuel will escape over the bridge wall. Thus while employing fuel
of the cheapest variety, substantially all the heat units are utilized and the furnace
is practically smokeless. The construction of the furnace ronders it absolutely
safe against explosions even when coal dust high in sulphur is fed thereto. If
desired only one mixing chamber H need be employed, but the best results can
be obtained by employing two located as shown and described.
Having now particularly described and ascertained the nature of the said
invention as communicated to me by my foreign correspondents in what
manner the same is to-be performed, I declare that what I claim is : —
1. In a fuel dust furnace, the combination with the fire-chamber, of means
at one side thereof for spraying fuel dust into said chamber, comprising a mixing
chamber opening at its inner end into the fire-chamber, a steam blast pipe extend-
ing into the outer end of the mixing chamber, an upward extending fuel dust
feed-tube communicating at its lower end with said mixing chamber between the
blast-pipe and fire-chamber, and a fuel dust conveyer extending to said feed-tube,
substantially as and for the purpose set forth.
2. In a fuel dust furnace, the combination with the fire-chamber, of means at
one side thereof for spraying fuel dust into said chamber, comprising convergent
mixing chambers opening at their inner ends into the fire-chamber, steam blast-
pipes extending into the outer ends of the mixing chambers, upward extending
fuel dust feed-tubes communicating at their lower ends with the mixing chambers
between the blast-pipes and fire-chambers, and a fuel dust conveyer extending to
said feed-tubes, substantially as and for the purpose set forth.
3. In a fuel dust furnace, the combination with the fire-chamber, of means at
one side thereof for spraying fuel dust into said chamber, comprising a mixing
chamber opening at its inner end into the fire-chamber, a steam blast-pipe extend-
ing into the outer end of the mixing chamber, an upward extending fuel dust
feed-tube communicating at its lower end with said mixing chamber between the
blast-pipe and fire-chamber, and a fuel dust conveyer extending to said feed-
tube, said feed-tube having an air inlet, substantially as and for the purpose set
forth.
4. In a fuel dust furnace, the combination of a fire-chamber provided with
heat storage sides and top incased in heat insulating material, and means at one
side of said chamber for spraying fuel dust into the same, comprising a mixing
chamber opening at its inner end into the fire-chamber, a steam blast-pipe extending
into the outer end of the mixing chamber, an upward extending feed-tube com-
municating at its lower end with said mixing chamber, and a fuel dust conveyer
extending to said feed-tube, substantially as and for the purpose set forth.
5. A fuel dust feeder for furnaces, comprising a supply bin for the dust, an
overflow receptacle, a dust conveyer extending from said bin to the overflow
receptacle, a distributing receptacle in the line of said conveyer, and a dust
conveyer extending from the distributing receptacle to the furnace, substantially
as and for the purpose set forth.
6. A fuel dust feeder for furnaces, comprising a supply chamber, an overflow
chamber, a dust conveyer extending from said supply chamber to the overflow
chamber, one or more distributing receptacles in the line of said conveyer, a dust

page_text: conveyer extending from the distributing receptacle to the furnace, and an over-
flow conveyer extending from the lower side of the overflow chamber back to the
said supply chamber, substantially as and for the purpose set forth.
OCL 1
£T 1007
BOULT & WADE,
Agents for the Applicant.