A Smokeless Furnace.
Year: 1897

page_text: Date of Application, 23rd Mar., 1897-Accepted, 22nd May, 1897
COMPLETE SPECIFICATION.
A Smokeless Furnace.
1, HERBERT ALLEN WHEELER of the City of St. Louis, in the State of
Missouri, one of the United States of North America, Mining Engineer, 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 thereof, reference being bad to the drawings hereunto annexed and to the
figures and letters marked thereon; that is to say:-
My invention relates to improvements in the fire box or furnace of boilers, kilns,
roasting and calcining furnaces, and other devices, where the production of heat
without smoke is desired, with a maximum economy of fuel, with a uniform
maintenance of the heat, an avoidance of the waste of fuel that arises in cleaning
fires, when using grate bars, and a minimum cost in the erection and maintenance
of the furnace. With these objects in view, my invention consists of the novel
devices and combinations hereinafter described and specifically claimed.
In the accompanying drawings,
Figure 1 is a longitudinal section through the fire place and boiler.
Figure II is a front elevation of the fire place.
Figure III is a plan of the fire place, with the top protecting iron plate in
removed to better show the construction.
Similar letters refer to similar parts of the drawings.
Of the various applications that may be made of this very economical, inexpensive,
smokeless furnace, I have shown in applied to a steam boiler "A" for making
steam, as this is the field in which there is the greatest demand for a smokeless,
inexpensive, durable furnace, in order to overcome the smoke nuisance in the large
cities, but I do not limit it to this field, as there are many other applications where
these features are very valuable and desirable as in kilns for lime, cement and clay
wares, roasting, calcining, and heating furnaces, or any purpose where the most
economical production of heat is desired with the avoidance of smoke, and a
minimum of cost for the erection and repair of the furnace.
The design herein described is to overcome the objections to the perishable
nature of the fire pots and other iron work heretofore proposed by substituting fire
brick, which will cost less to erect, be very much more durable in withstanding the
heat, and will not be subject to the warping and cracking of the exposed iron work,
while it has the same advantages of economy in fuel and smokeless character of the
fire of said prior devices.
37
The boiler "A" is hung by lugs "C" on the side walls "B" in the usual manner,
while the up-take "E" and stack "F" are of the usual pattern common in boilers.
Instead of usually carrying a fire on grate bars "X" as in the current practice,
I prefer, when the fuel permits to employ a dead or solid bottom 1 of fire brick
that sets on a sand bed "k." The fuel is fed through the firing hole "
into a
forechamber "," and spreads out on the solid bottom "1" to the base of the fire
bridge "G," and into the ashpit doorway "e." The forechamber "w" is kept filled
at or about the firing hole "c." Air is supplied for carrying on the combustion at
the base of the forechamber " "
through the ashpit arch "e," which extends
across the fire place, and through the firing hole "c." A curtain wall "b" that is
carried by an arch "g" of fire brick or other refractory material, separates the
forechamber "w into which the fuel is fed, from the combustion chamber " a
which latter is formed by the curtain wall "b," the fire bridge "G" and the side
"
10
"

page_text: walls "B." The fire bridge "G" is backed by earth filling "H" in the usual
manner, which latter extends to the rear of the boiler as shown.
The forechamber " 20 " is formed by the curtain wall "6" a front wall of fire
brick "d" and corbelled fire brick walls "h" that drop back to the special side
walls "." The corbelled walls "h" contract the fire walls "c" to suitable size for
feeding the fuel and cleaning the walls of clinkers, and to conform in outline to the
slope that the fuel takes when fed into the firing hole "c."
The front wall "d" has the ash pit arch "f" at its base for the admission of air,
the removal of clinkers, and the cleaning of the fire through the doorway or
openings "e" which is covered by a swinging door "7" that is hung on hinges","
that are suspended from a front plate "n of cast iron or other suitable material
that is held in place by anchor bolts "s."
"
The top of the fore furnace is protected by the metal plate "m " of cast iron or
other suitable material that is held in place by the anchor bolts t " and which
has the firing hole " C. This firing hole" C "is covered by fire clay tiles, or other
suitable material "p," or a hinged metal door may be substituted for the tile.
"
The curtain wall "6" is protected and supported by a front plate "o" of cast
iron or other suitable material that is anchored by the anchor bolts "v." Special
buck staves and tie-rods "D1" support the arch "g" that carries the curtain
wall "b."
The side walls "B" are held together by the buck staves and tie-rods “D” in
the usual manner.
W
"
"
The operation of the furnace, or fire box consists in filling the forechamber "w"
with coal or other fuel, after lighting in the usual manner, up to or about the
firing hole "c" and allowing the fire clay tiles or door p to remain open. The fuel
spreads out in a conical pile from the front wall "d" to the fire bridge "G" and
into the ash pit "e." The air enters through "e" as the door "q" is kept open
and passing through the mass of fuel in the lower portion of the forechamber"
creates an intense heat in front of the arch "f," which so softens the ashes of the
fuel into a clinker that it slowly runs as a pasty mass out into the ash pit "e" where
from time to time it is removed. As the air passes through the thick bed of fuel it
first oxidizes the latter into carbonic acid (CO2) but this is converted into the
imperfectly burned condition of carbonic oxide (CO) as it passes still further into
the incandescent fuel and imperfect combustion would result with a consequent
waste of fuel if it did not meet with an excess of oxygen that enters as a down
draft through the fire hole "c" and passing through the comparatively thin bed of
fuel, above the curtain wall "" enters the combustion chamber ",
a," in a heated
condition, where there is time, space and favorable conditions for the perfect com-
bustion of the carbonic oxide, resulting from the air entering through "e," and the
hydro-carbon gases that are distilled from the fresh fuel added through "c." The
large space, highly heated surrounding walls of fire brick, and time allowed for
mixing, and burning in this combustion chamber "a" result in a high heat, perfect
combustion of the fuel, and the avoidance of smoke. While the absence of iron
work, which is exposed to a high heat, and the simplicity of the construction, result
in a low cost of construction, and a very low expense for repairs. As the fuel is
added frequently, and in small amounts, no cold air can enter the furnace as it has
to pass either down through the bed of fuel, in the upper portion of the fore-
chamber" 10 "and pass the hot arch of fire brick "g" or through the heavy mass
of fuel in the lower portion of "w"; this maintains a uniform heat, which is very
desirable for boilers, kilns, and heating furnaces, prolongs the life of the furnace
and boiler, and gives a superior quality of ware in burning clay goods.
The long period required for the fuel to pass from "C" to "e" gives it time to
be completely burned, so that only clinkers, slag and ashes fall out at "e," which
are removed from time to time, and the more frequently they are removed the
higher the heat will be, while it avoids the waste of fuel that occurs when cleaning
grate bars of clinkers, when more or less unburnt fuel is always hauled out with
the clinkers.

page_text: The forechamber "w" projects sufficiently in front of the boiler to enable the
front wall "d" and curtain wall "b" to be cleaned of adhering clinkers, with a
sharp bar through the firing hole "c," while the clinkers that adhere to the bottom
and sides of the furnace are removed through the ash pit door way "e."
The lower portion of the forechamber " to" partially performs the function of a
gas producer in making carbonic oxide, while the upper portion with its restricting
curtain "6" performs the function of a re-heating down draft furnace, for pre-
heating the air before meeting with the carbonic oxide in the combustion
chamber "a." If the fuel in the upper portion of "w" is kept too deep it will also
become more of a gas producer than a pre-heater, while if the depth of the fuel is
kept too thin, it will not sufficiently heat the air to ensure perfect combustion in "a."
The design of the furnace enables with moderate experience the maintenance of a
proper depth of fuel in the upper portion of "w," above the arch "g" according to
the size and kind of fuel to secure perfect combustion.
"
The ashpit door " 7" may be hinged by overhead or side hinges, or hung on
rollers or slides, or operated in any other convenient way.
The ashpit door way
$6
e
may be made as one simple large arch, spanning the
entire width of the furvace, or it may be subdivided into two or more smaller
arches.
"
The firing door “ C may be made of one large central opening, or it may be
subdivided into two or more smaller openings. It may be covered by loose
fire-clay tiles, or hinged doors, rolling doors, or sliding covers of metal or any
suitable material.
The front wall "d," curtain wall "b," special side walls "i" and corbels "h,"
fire bridge "G," and bottom "1" may be made of fire brick, steep, ganister, or any
suitable refractory material.
When the fuel is slack, sawdust, or other material that is too fine to enable the
air to enter satisfactorily, or where for any reason, grate bars are desirable for
carrying the fire, instead of using a dead bottom, then grate bars "a" carried on
bearing bars "y" are used, as shown in Figure 1., which still secures the advantages
of perfect combustion, and a smokeless fire, but the first cost and maintenance is
higher than when firing on a dead bottom of fire brick, from the greater expense
and shorter life of the iron bearing bars and grate bars.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
1. A furnace comprising the solid front wall d, the ashpit arch located in the
front wall, the solid curtain wall b, the arch g located in the curtain wall, the down
draft firing hole C, the forechamber W located between the front wall and the
curtain wall, the corbelled walls h, the fire bridge G, the combustion chamber
located between the curtain wall and the fire bridge, and the fuel bottom l, extending
beneath the curtain wall, the firing hole and the combustion chamber, substantially
as described.
2. A furnace, comprising the solid front wall d, the ashpit arch flocated in the
front wall, the solid curtain wall "b," the arch g located in the curtain wall, the
down draft firing hole and forechamber W located between the front wall and
the curtain wall, the corbelled walls h, the fire bridge G, the combustion chamber
located between the curtain wall and the fire bridge, and the fuel bottom / extending
beneath the front wall, the curtain wall, the firing hole and the combustion chamber,
substantially as described.
Dated this 23rd day of March 1897.
WHITE & WOODINGTON,
27 Southampton Buildings, London, Agents.