Improvements in Steam Boiler Furnaces.
Year: 1894

page_text: Date of Application, 26th June. 1894-Accepted, 15th June, 1895
COMI LEIE STEIFICATION.
Improvements in Steam Boiler Furnaces.
I, OREL DIGHTON ORVIS, of No. 839 Garfield Boulevard, Chicago, in the
County of Cook, and State of Illinois, United States of America, 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 :-
My invention relates to down draught furnaces. Its object is to secure a con-
struction whereby more perfect combustion of the fuel may be obtained than is
practicable in furnaces of this class now in use; in which the furnace may be fed
below the down draught grate bars if desired; in which provision is made for
complete combustion of the smoke, and in which the highest possible efficiency in
steam production is secured.
The invention consists in the use of two fire-boxes whose grate bars are water
pipes communicating with the boilers; a cylindrical retort lying between the two
fire-boxes and leading to the combustion chamber, such retort being open along
its under side to receive the products of combustion; and such other parts and
arrangement of parts as are hereinafter described.
In the accompanying drawings,
]
Figure represents the front plate of a steam boiler furnace ;
Figure 2 is a plan section on the line 2-2 of Figure 1;
Figure 3 is a vertical longitudinal section on the line 3-3 of Figure 1;
Figure 4, is a transverse vertical section on the line 4-4 of Figure 3 ;
Figure 5, is a plan section on the line 5-5 of Figure 1;
Figures 6 and 7, are transverse sections showing modified forms of a retort;
Figure 8, is a side elevation of the pipe system of the section of the retort shown
in Figure 7;
Figure 9 is a transverse vertical section through the grate bars showing the
application of my invention to the Lancashire form of steam boiler furnaces,
and
Figure 10, is a plan section on the line 10-10 of Figure 9.
The passage of the distilled vapours through the upper grate bars involves the
loss at that point of much of their temperature, the bars being filled with water
drawn from the boiler at its coolest point, and as a result it is difficult to maintain
the combustion for the purpose of burning the carbon. By the use of a long
retort through which these vapours are passed after leaving the fire-box their
temperature is again raised to the combustion point. The efficiency of this retort is
increased by the free use of fire-brick which speedily become heated to a high
degree.
In the drawings I show at A, Figs. 1, 2 and 10, the face plate of a steam boiler
furnace, the front end of the boiler extension being shown at B. Firing doors are
represented at a, a, and the ash pit doors at a', a'. The side walls of the furnace
are shown at A¹, A', Figs. 2, 4 and 9, and a transverse wall A, cuts off the back
end of the fire-boxes and extends to the crown sheet of the boiler. The grate
bars C, are water pipes and are set staggered," that is, alternate bars are at
different elevations. These giate bars are longitudinal with the fire-box and their
rearward ends c Fig. 4, extend downwardly and communicate with the cross-
head D, which is fed by a pipe D', leading from the bottom of the boiler B¹, at the
rearward end.
66
The pipes C, communicate at their forward ends with the cross-head E Fig. 5,
and pipes e, e lead from this cross-head to the boiler, entering it at a greater

page_text: elevation than does the pipe D', so that free circulation is insured through the
pipes C, and their steam generating capacity thereby augmented.
Two sets of these grate bars are used and between them extending from the
front wall backwardly through the wall A2, is a cylindrical retort whose chamber
is shown at F, and which has an opening through its lower side. Fuel is thrown
upon the grate bars, C, through the doors a, and these doors remain open to
supply the air feed. The plane of the grates described is above the longitudinal
opening in the retort and hence the draught is downwardly and into the retort.
A central flue O, extends backwardly below the retort from the front wall of
the furnace and is provided with a damper controlled opening leading thereto (
The flue O Figs. 3 and 4, is formed by the use of a pair of sets of vertical grate
bars P, P and a roof plate, o*. A deflecting plate Q, is set obliquely below
and longitudinal with the grate bars C, extending from the floor of the
furnace near the grate bars P, P to the side walls A¹. Fuel falling through
the upper sets of grate bars C, strikes upon the deflecting plates Q, and is thrown
against the grate bars P. Air entering through the opening O¹ Figs. 1 and 2, and
the flue O, keeps up the combustion of this fuel and consumes it. The ashes are
readily worked through between the grate bars P, and thence drawn out by the
use of a hoe; the front end of the flue O being closed by a door 0².
The plate O*, is provided with a longitudinal row of apertures into which are
set short pipes n, Fig. 3 open at both ends. A slide bar R, having corre
sponding apertures is carried by suitable ways upon the under surface of the
plate o, and has a longitudinal movement, so that its apertures may be caused to
register with the lower ends of the pipes n, or the pipes may be closed by shifting
the slide bar R. This slide bar extends through the front plate A, of the furnace
and is pivotally connected to a lever r, carried by a suitable hanger attached to
the front wall of the furnace, whereby it may be operated.
I prefer to flatten the upper end of the pipes n, so that their openings are in the
form of slots, thereby guarding against the accidental entry of any cinders which
might be too large to find their way through to the flue O.
The pipes n, are protected from the intense heat to which they would otherwise
be exposed by being enclosed by fire-brick, as shown at N. These fire-brick also
serve as supports for two rows of brick as shown at M, reaching to the under side
of the retort and interposed between the grate-bars and the retort opening. These
fire-bricks M, are spaced apart so as to permit the passage between them of the
burning gases. I prefer to place a third row of fire-brick transversely across the
retort opening as shown at K, these brick being similarly spaced apart.
The retort may be variously constructed, though preferably being cylindrical in
form, and having a longitudinal opening g, Fig. 4, at its under side and substantially
through its entire length. This construction provides for the free entry of the
burning gases, and an ample Hue F, for their passage backwardly to the com-
bustion chamber, but the precise form of the retort or the means of ingress to it
are immaterial.
In Figures 2, 3, 4, 5, 9 and 10, the retort consists of a hollow shell G, made of
boiler steel, and supported at its forward end by the front wall of the furnace, and
at its rearward end by the transverse wall A. A water leg d', leads from the
cross-head D, to the rearward end of the shell G, entering it at its lower side.
Discharge pipes g', lead from the forward end of the shell, G, to the pipes e, which
communicate with the upper part of the boiler, the pipes g', communicating with
the interior of the shell near its upper side. By this arrangement of piping
provision is made for the free circulation of water through the shell and for the
rapid generation of steam.
The shell G, may be lined with fire-brick, as shown at H, Fig. 4 for maintaining
the high temperature of the burning gases, or the shell G, may be dispensed with
entirely and the walls of the retort be composed of fire-brick as indicated at H', H2
Figs. 6 and 7. In this construction the two rows of fire-brick K, serve the
additional purpose of supports for the retort.

page_text: In Figures 7 and 8, I have shown pipes I, imbedded in the walls of the retort
and extending throughout its entire length, annular headers i', being located at
the rear and front of the retort, respectively, for feeding and discharging these
pipes.
Small pipes e Figs. 2 and 5, lead from the front end of the shell G, or from the
front header, through the face plate of the furnace, and are closed by the
caps 2 Figs. 1, 2 and 5. These pipes afford convenient access to the interior of
the shell, or header, for cleaning. At d³, Figs. 4 and 9, are shown hand openings
to the cross-head D, for the same purpose.
Lancashire boiler furnaces are provided with a longitudinal ash pit S Fig. 9.
In this form of furnace I therefore dispense with the flue O, and consequently
with the form of grate bars P, and the air supply used in connection with it as
already described, and place a set of grate bars p, horizontally over this ash pit.
The deflecting plates Q, reach to the sides of this set of grate-bars and the fuel
falling from the down draught grates, is consequently deposited upon them and
burns directly below the opening of the retort. In this construction, as well as in
that previously described, new fuel may be fed directly to the lower grates, a very
decided advantage in case of a sudden demand for increased steam pressure, and
the resultant vapours will be consumed as effectively as when the firing is limited
to the upper grates.
I show in Figure 10, the flues b, b, forming a feature of the Lancashire boiler.
The rearward end of the retort is directly in front of these flues, so that the flame
is divided and enters both of them. In the style of furnace shown in Figure 3, a
bridge wall L, is located immediately back of the retort for the purpose of
carrying the burning gases up to the boiler, its general form being shown in dotted
lines in Figure 4.
More or less fire-brick will be used in conjunction with the retort according to
the kind of fuel intended to be used. A fuel rich in carbon will necessitate the
using of a liberal quantity of fire-brick in order that the temperature may be
maintained and in this case the open brick work as shown at M, K, will be
especially serviceable.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
clain is :-
1. In a down draught furnace for steam boilers the combination with a pair of
fire-boxes, of a chamber below the grates, a tubular flue located between the fire-
boxes and opening substantially through its entire length to the chamber below
the grates, and a wall closing the rearward end of such chamber, substantially as
described and for the purpose specified.
2. In a down draught furnace for steam boilers the combination with a pair of
fire-boxes, and with a wall closing the rear end thereof, of a chamber below the
grates, a tubular flue located between said fire-boxes and leading from this chamber
through said wall, substantially as described and for the purpose specified.
3. In a steam boiler furnace the combination with upper and lower fire-boxes,
and with a wall for closing the rearward end thereof; of a tubular flue leading
from the chamber between the two sets of grates through said wall, substantially
as described and for the purpose specified.
4. The combination with a pair of down draught fire-boxes for steam boilers, an
up-draught fire-box below them, and with the wall A2, for closing the rearward
end of said boxes, of a retort flue located between the down draught boxes and
leading from the chamber below them through the wall A2, substantially as
described and for the purpose specified.
5. The combination in a down draught furnace for steam boilers with chambers
above and below the grates closed at the rear, of a tubular water shell or
jacket forming a flue leading from the chamber below the grates, and means for

page_text: circulating water through such shell, substantially as described and for the purpose
⚫ set forth.
;
6. The combination in a down draught furnace for steam boilers having a pair
of fire boxes, of a back wall closing the chambers above and below the grates, a
tubular water shell or jacket located between the fire boxes and having its
central chamber in communication with the chambers below the grates and with
a combustion chamber behind the back wall, a boiler and service and return
pipes connecting the water shell or jacket with the boiler, substantially as
described.
7. In a furnace for steam boilers having two down draught fire boxes, the
combination with such boxes of a back wall for closing the fire boxes a tubular
water shell or jacket located between the fire boxes and projecting through the
back wall and having the rearward end of its central chamber open and a longi-
tudinal aperture for communication between its central chamber and the chambers
below the grates, fire bricks placed across the longitudinal aperture and spaced
apart, a boiler and service and return pipes connecting the water shell with such
boiler, substantially as described.
8. The combination, in a down draught furnace, for steam boilers with the fire-
box, a wall A2, for closing the rear end of such fire-box, and with a retort flue
leading from the chamber below the grates, through the wall A2, of an apertured
wall of fire-brick M, located across the line of draught from the grates to the
retort flue, substantially as described and for the purpose specified.
9. The combination in a down draught furnace, for steam boilers with the fire-
box, a wall A, closing the rear end thereof, and with a retórt flue leading from
the chamber below the grates through the wall A2, of air ducts leading from
without and opening to the intake aperture of the retort flue, substantially as
described and for the purpose specified.
10. In a steam boiler furnace the combination with down draught grates, of
inclined deflecting plates Q, located below such grates and up-draught grates
at the foot of such plates, substantially as described and for the purpose
specified.
11. In a steam boiler furnace the combination with down draught grates, a solid
wall, A2, at the rear of such grates, a retort flue at the side of such grates and
leading from the chamber below them through the wall A2, of up-draught grates
below and at the side of the down draught grates, and deflecting plates Q; below
the down draught grates and adapted to throw the fuel falling therefrom in the
direction of the up-draught grates, substantially as described and for the purpose
specified.
12. In a steam boiler furnace the combination of a pair of down-draught, and a
pair of up-draught fire-boxes, a wall, A³, closing the rear end of such boxes, a
retort flue located between the down-draught fire-boxes and opening to the fire-
box chamber along the underside and extending through the wall A2, a central
"air-flue, O, between the up-draught fire-boxes, vertical grates forming the side
walls of the air-flue, deflecting plates Q, below the down draught grates and
adapted to convey the fuel falling therefrom to the vertical grates, air openings
leading upwardly from the air flue, O, a damper for closing the air openings,
series of fire-brick spaced apart and interposed between the grates and the intake
aperture of the retort flue, and a series of fire-brick spaced apart and located
across such intake aperture, substantially as described and for the purpose
specified.
Dated thin orth do 1001
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.