Improvements in or relating to Furnace Grates.
Year: 1896

page_text: Date of Application, 11th Feb., 1896-Accepted, 9th May, 1898
COMPLETE SPECIFICATION.
Improvements in or relating to Furnace Grates.
I, JAMES LUTHER WHITE, a citizen of the United States, residing at
409 Hughitt Arenue, West Superior, in the County of Douglas, and State of
Wisconsin, United States of America, Manufacturer, 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 :-
The object of my invention is to provide an improved form of furnace grate
which is adapted for burning fine screenings or other finely divided fuel. To this
end the invention broadly consists in employing a series of grate bars normally
closely arranged together, and through which air under pressure may be forced for
supplying the necessary oxygen to the flame, said grate bars being capable of being
rocked wheu necessary, so as to enlarge the openings between the same when the
ashes are to be removed, all as I will hereinafter describe and claim.
The invention further relates to various improved details of construction which
will be also explained and embodied in the claims.
For a better comprehension of the invention, attention is directed to the
accompanying drawings forming a part of this Specification, and in which :-
Figure 1, is a perspective view partly in section of a portion of a furnace of
ordinary construction, provided with my improved grate;
Figure 2, a detached front elevation of four grate bars illustrating the mechanism
for rocking the same;
Figure 3, is an enlarged sectional view of a portion of one of the grate bars
and air box on line A, B, C Fig. 5.
Figure 4, an enlarged side elevation partly in section of a portion of one of the
grate bars, illustrating the mechanism for rocking the same; and,
Figure 5, is an enlarged sectional view of one of the complete grate bars.
In all of the above views corresponding parts are represented by the same
characters of reference.
In Figure 1, I show a portion of an ordinary furnace embodying my present
invention, it being understood that the device may be made use of with many other
varieties and types of furnaces and fire boxes.
1, is an air box made preferably of cast iron or other suitable material, which is
set into the bridge wall of the furnace, its front side being preferably flush with
the same.
2, is an air pipe leading into this air box for supplying air to the same under
pressure from a fan or blower. 3, 3, are short tubular bearings for the grate bars
communicating with the interior of the air box through which air is supplied to
the grate bars.
4, represents the main portion of the grate bars made preferably of the shape
shown in Figure 5 in cross section. It will be observed from an inspection of this
view that the main portion of each grate bar is provided with a generally semi-
cylindrical lower portion of greater thickness than the other parts, so as to insure
strength, with tangential sides extending from the same, and with a peaked upper
portion.
A lug 4' is formed at each side for securing the auxiliary grates in position, as
I will hereinafter describe.
The rear end of each grate bar 4 is supported on one of the tubular bearings 3,
and the front end of each grate bar is closed and is provided with an integral
bearing pin 7, which works in a slot or open bearing formed in the cross bar 6.

page_text: This cross bar 6, is provided at each end with a supporting foot or web 9, which
rests upon a pier 10 at each side of the furnace, and near the front end thereof.
By means of this construction, the grate bars can be very easily removed when
necessary.
The main portion 4 of each grate bar is provided near its front end with a
depending arm 11, and connecting these depending arms is a cross bar 12 adapted
to rock back and forth.
15, is a short shaft mounted in a bearing 15' formed in the cross piece 6 and in a
bearing 15", in the front wall of the furnace. 16, is a hand lever on the outside
of the furnace for rocking this shaft. 14, is an arm keyed rigidly to this shaft 15
behind the cross bar 6, and connecting the lower end of this arm 14 with the
rocking bar 12, is a link 13.
5, 5, represent removable auxiliary sections which are applied to the upper
part of each grate bar, and on which the fuel is consumed. The upper portion
of each grate bar 4 is provided with a groove therein (see Figure 5) which
receives the longitudinal web 22 on each auxiliary section 5. These auxiliary
sections 5 are made of any desired length, five of such sections being shown in
Figure 1 for each grate bar. Each auxiliary section 5 is of a generally semi-
cylindrical shape, being provided with webs 21, 21, at each end and with turned in
fingers 8, which engage beneath the lugs 41 on the grate bars 4, so that the
auxiliary sections will be held firmly in position.
By making these auxiliary sections of a generally semi-cylindrical shape in
cross section as explained, great strength is obtained, and I am further enabled to
secure a very large surface in which to form air passages as I will describe, by
supplying the necessary air to the fire. This shape for the auxiliary sections is
also of advantage, as it enables the sections to be quickly and effectively freed of
ashes when shaken only to a slight extent.
The upper inclined surfaces of each grate bar 4 are each provided with a series
of slots 18 therein, separated by wedge-shaped pieces 23 (Figure 3) whereby the
slots 18 will be contracted towards the upper end, and the main portions on each
side of the auxiliary sections 5 are provided with other slots 20 therein separated
by wedge shaped pieces 19, so as to be also contracted towards the upper end,
whereby ashes and fine particles will be prevented from entering said slots. The
slots 20 in the auxiliary sections are preferably considerably longer than the
slots 18 in the grate bars, whereby the air passing through the longer slots will
have been expanded, more or less, and its pressure reduced. In this way a large
amount of air can be supplied to the fuel, without being of sufficient pressure to
disturb the fine particles which are being consumed.
By forcing the air jets upwardly into the fuel, a draft will be formed upwards
between the several grate bars, by which air from beneath the grate bars will be
caused to travel through the fuel, thereby materially augmenting the supply of
oxygen to the same.
In actual practice when the grate bars are in their normal position, the
auxiliary sections 5 will occupy substantially horizontal planes, and will be
arranged very closely side by side, so as to prevent the fine fuel from passing
between them.
The fire is built on the auxiliary sections in the usual way, and air is forced
through the air pipe 2 into the air box 1. This air under pressure passes into the
tubular bearings 3, into the main portions 4 of the grate bars, and thence through
the slots 18 and 20 into the fuel where it supplies the necessary oxygen to insure
the proper combustion.
This air in passing from the slots 18 through the slots 20 will have suffered a
more or less reduction in pressure, for the purpose stated. When the fire is
shaken, the lever 16 is operated by an up and down movement which rocks the
bar 12 back and forth, and oscillates the different grate bars simultaneously, so as
to separate the auxiliary portions 5, and incline the same as shown in Figure 1,
first to one side and then to the other. The ashes will therefore drop to one

page_text: side or the other of each grate bar, after which the bars are returned to their
normal position.
By making use of auxiliary sections 5 for each grate bar, they may be easily
removed when burned out by simply elevating the front end of the grate bar and
sliding said sections towards the front thereof. It will be obvious that instead of
making use of the particular mechanism for rocking the various grate bars as
described, the bar 12 may be continued through the side of the furnace and be
provided with a handle thereon, by which it may be actuated.
By making use of auxiliary sections on which the fire is built, it is evident that
the grate bars proper cannot be damaged in any way, since the two elements are
always insulated by an air space. When the auxiliary sections are burned out,
they may be quickly and easily removed, and owing to the preferred shape of these
sections, they may be made very cheaply.
Although I have particularly described my improved construction of grate bars
as being used with a forced draft, it is to be understood that they may be advan-
tageously and effectively used with a natural draft, and unless specifically stated to
the contrary, I desire to have my claims so construed.
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. As a new article of manufacture, an improved grate comprising a slotted
main portion and a slotted removable upper portion secured thereto with an air
space between the two portions, substantially as set forth.
2. As a new article of manufacture, an improved grate comprising a hollow
main portion having slots therein, a removable auxiliary portion secured thereto
above said slots, and slots in said removable auxiliary portion, substantially as set
forth.
3. As a new article of manufacture, an improved grate comprising a slotted main
portion 4, a slotted removable auxiliary section 5 made semi-circular in cross
section, substantially as set forth.
4. As a new article of manufacture, an improved grate comprising a main
portion 4 having inclined slotted upper faces, a removable auxiliary section 5
secured to said main portion 4 and provided with slots therein, substantially as
set forth.
5. As an improvement in furnace grates, the combination of grate bars mounted
at their rear ends on bearing pieces, and at their forward ends on a supporting
bracket 6; depending arms 11, 11, secured to the forward end of each grate bar;
a rocking bar 12 connecting said depending arms; a shaft 15 mounted in said
bracket 6 in the front wall of the furnace; an operating lever 16 secured to said
shaft; an arm 14 keyed to the inner end of said shaft, and a link 13 connecting
the lower end of said arm 14 with said rocking bar 12, substantially as set
forth.
6. As a new article of manufacture, an improved grate bar composed of a main
portion having inclined slotted upper sections, and provided with a lug 4' at each
side; removable auxiliary sections 5 provided with a longitudinal bearing 22,
supported by the upper portion of the grate bar 4, and with turned in fingers 8
engaging beneath said lugs 4'; a strengthening web 21 for said sections; and slots
in the inclined portions of the grate bars and in said auxiliary sections, substantially
as set forth.
Dated this Tenth day of February 1896
JAMES LUTHER WHITE,
By W. Fairburn-Hart,
Agent.