Year: 1887

page_text: I, EZRA WILLIAM VANDUZEN of Newport, Campbell County, Kentucky, in the
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 first object of my invention is to provide a suitable lining for the doors
and walls of the furnace, which will accomplish two purposes, first, to prevent the
parts from burning out, and to resist the tendency of the heat to warp them out of
shape; second, to allow a proper admission of air through orifices pierced in the
doors and walls, and delivering the air to the furnace-chamber in a partially heated
condition thereby increasing the efficiency of the combustion of the fuel.
Another object of my invention is to provide suitable means for admitting a
graduated or regulated amount of air into the rear of the firo-chamber.
Again, the upper part of the grate-bar is heated to a much higher degree than the
lower part, because of its immediate contact with the fire. In consequence of this
un-equal heating, the upper part expands more than the lower part of the bar. This
difference in longitudinal expansion between the top and the bottom of the bar, causes
it to bow upwardly. This shape is not altogether lost when the bar is cooled, and
after continued use, the bar finally assumes a permanently curved shape, in which the
longer or convex side is uppermost. Besides interfering with the fire, a bar so
distorted burns out very quickly. In addition to the distortion in a vertical plane, the
bar also expands laterally, and when one side expands more than the other, the bar
becomes permanently curved laterally, in the same manner as the permanent bowing
in the vertical direction was produced. This lateral distortion produces a wide space
between the bars, allowing the fuel to drop through, and also allowing the hot coal
to come in contact with the sides of the bar, burning them out, and aiding in warping
them laterally. To avoid these defects in the construction of the bar, and dis-
advantages arising therefrom is a further object of my invention.
In the ordinary furnace the combustion of the fuel is more rapid, and the heat the
greatest at the rear, and in order to equalize the heat, causing the fuel to burn more
rapidly in the front than in the rear, I have provided means for regulating the

page_text: admission of air to the rear part of the ash-pit, and also means for retarding the
admission of air through the grate-bars.
The several devices accomplishing these objects are illustrated in the accompanying
drawings making part of this specification, and in which—
Figure 1 is a longitudinal vertical section of my improvement. Figure 2 is a.
horizontal sectional view on line æ—a of figure 1. Figure 3 is a central vertical section
of the door and lining. Figure 4 is an inside perspective view of the door and lining.
Figure 5 is an elevation of the outside of the furnace door. Figure is a front
elevation of the rear ash-pan door. Figure 7 is a broken perspective of the rear
grate-bars, for the furnace shown in figure 1. Figure S is a perspective view of my
improved grate-bar. Figure 9 is a vertical cross-section taken on the line a- of
figure 8. Figure 10 is an enlarged view illustrating the manner in which the
vertical slots in the bars are gradually closed by continuous use. Figure 11 is a top
view of a grate made with my bars, and illustrating two methods of arranging the bars.
Figure 12 is a side elevation of a smelting furnace grate-bar.
Referring to figures 1 to 7 inclusive, A represents the walls of the furnace, B the
boiler, C the ash-pit, D the division wall in the ash-pit, E the fire-chamber, F the
front series of grate-bars, and G the rear series.
The grate-bars G are supported at their rear ends by the rear-wall H, which is
provided with usual arches for flues. The front ends of the grate-bars G rest on the
division-wall D. The rear ends of these grate-bars are bent or inclined upward so as
to keep an open space at the rear for the admission of air between and through the
grate-bars.
F represents the front grate-bars, which are supported by the front wall and the
partition wall D. a represents lugs on the grate-bars to prevent their warping
laterally out of line. 1 represents doors placed in orifices of the division-wall D
which divides the ash-pit into two chambers. These doors are provided with orifices 2
for the admission of air into the rear ash-chamber 3. These orifices may be covered
with a damper if desired, but I prefer to regulate the quantity of air admitted by
partially opening the doors.
As a further means for regulating the admission of air into the rear end of the
combustion chamber in a heated condition, the rear bars G are made to come together
at the top surface, and are pierced with orifices 4 to allow the escape of ashes and the
admission of air, but the rear grate-bars may have the usual form and still accomplish
several objects of my invention.
represents ribs, of which one or more may be used, to prevent the bars or plates
from warping. Two results are accomplished by these rear bars; first, the small
amount of air openings retard a rapid combustion at the rear; and, second, maintains
a nearly uniform heat and combustion of the fuel at the front and rear of the fire-
chamber. 5 represents the lining of the furnace doors and walls. It is of shell form
and rigidly attached thereto by bolts 10, forming an open space into which the air is
received, if desired, through orifices 9, pierced in the doors or wall. It is shown at 6
as attached to both the doors and front wall of the furnace. This lining may be of
cast metal or fire-clay. It is provided with slots 7 and 8 which serve the following
purposes.
The slots S allow the lateral contraction and expansion of the face of the lining
with little liability of breaking or warping due to the heating of the same.
The slots 7 are for the same purpose with reference to the contraction and expansion
of the edges of the lining shell.
Referring to figures 8 to 12, inclusive will be seen my improved and preferred
form of grate-bar.
The bar A is made of suitable depth throughout, to support the weight put upon it.
The sides taper slightly from above downward as shown in figure 9. Each end of the
bar is joined in the customary manner. The bar for smelting furnaces being provided
at one end with extension or handle B, and at the other end with the end portion B¹,
as shown in figure 12. The bar for boiler and heating furnaces is provided at each
end with the end portion B'. These end portions are also preferably provided

page_text: with the side projections e separating the bars from one another. Ridges C, C, placed
at suitable intervals along cach side of the bar also assist in keeping the grate bars at
a proper distance from each other.
The extension-piece B and the ends B¹ in one case, and the ends B' in another case,
rests on supports in the grate.
The upper edge of the bar is provided with a number of transverse slots D. It is
essential to the successful working of the bar that these slots conform to certain rules ;
first, the slots should not be placed close together, the length of metal between
adjacent slots being preferably from three to four times the width of a slot. Second,
the slots should be cut rather deep into the bar, so that they may extend entirely
through that part of the bar which is subjected to the greatest heat. Third, it is
preferable to make the slots tapering as shown in the drawings, but this point is not
essential to a successful operation of the bar.
When the bar is in use, the upper part expands in the way already described for
grate-bars in general; but in this case the bar is not distorted, because the excess of
longitudinal expansion of the upper part of the bar is accomodated by the slots D).
I have discovered that the permanent expansion of the bar is confined at its upper
part from one-third to one-half, and the slots D extending preferably through about
two-fifths of the whole depth of the bar, entirely compensates for the change in shape.
When the slots are placed too close together, the intervening metal parts become mere
stilts projecting upward from the bar proper, and burn rapidly away, and soon lets the
fire down upon the lower portion of the bar, and consequently fails to protect that
part of the bar from distortion. When the slots are not sufficiently deep, they
likewise fail to prevent distortion, because the metal immediately below them belonging
to the part of the bar which should not be subject to permanent expansion, being
heated to a higher degree, produces a degree of distortion in the manner already
described.
In my bar, the expansion of the upper part of the bar is confined to, and divided
between the sections E, which are between the slots D. Each section E as it expands
extends each end of its own section longitudinally, but does not buckle upward. The
permanent expansion of the section E gradually fills up the slots D, as shown in
Figure 10, where the dotted lines indicate the outline of the slot after permanent
expansion has occurred. The bars are sometimes made so that in arranging the grates,
the slots D are opposite each other as shown in figure 11, and again the bars are made
so that when placed in position, each slot D is opposite one of the sections E, also
shown in figure 11.
The advantages of a grate-bar possessing the properties of my bar as above set
forth are quite obvious. Such a bar costs less than a bar not provided with slots, and
its durability is much greater. My grate-bar also admits more air to the fire, and
supports the fuel on a less surface, and there is less obstruction to the air which
supplies the fire with oxygen in reaching the burning fuel, than in the ordinary grates.
A grate provided with a set of my bars will always have a flat surface, mach
facilitating firing, and securing greater uniformity in the fire itself.
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 claim is :-
:-
1. A grate-bar provided with the slots D, extending entirely through the
permanently expansible portion of the bar, as and for the purpose set forth.
2. The combination with a furnace having an ash-pit, of the division wall D
separating the ash-pit into two chambers, and supporting two sets of grate-bars, one
having large air-spaces between the bars and the other small air-openings, said wall
being provided with an orifice, and the door 1 located in said orifice, and having
orifices 2, substantially as described.
3. The combination with a furnace having an ash-pit, of the division-wall D
separating the ash-pit into two chambers and provided with an orifice, two sets of
grate-bars supported by the division-wall, the front set of grate-bars being open and
the rear-grate bars abutting each other at their top surface and pierced with air

page_text: openings and the perforated door 1 seated in the orifice and hinged to the division-
wall to swing into and out of said orifice, substantially as described.
4. The combination with the furnace having the rear wall H, and ash-pit, and a
division-wall D separating the ash-pit into two chambers, with a perforated door 1 in
the division-wall, the front grate-bars F, and rear-grate bars G, supported by the
division-wall and rear furnace wall and provided with a series of perforations 4,
substantially as described.
5. The combination of the furnace ash-pit divided by the partition-wall D, and the
front furnace wall A, and rear wall H, with the rear grate-bars G abutting each other
at their top surface and pierced with the air-openings 4, said grate-bars supported at
their ends, respectively, by the rear furnace walls and the division-wall, and the open
front grate-bars F, supported at their ends, respectively, by the front furnace-wall and
the division-wall, substantially as described.
6. A shell lining 5 attached to the door or wall of a furnace, provided with slots
pierced in its face, arranged as shown, substantially as specified.
7. A shell lining 5, provided with slots 7 and 8, pierced through said shell, attached
to the door or wall of a furnace, provided with slots pierced in its face, substantially
as specified.
8. In combination with a shell lining 5 attached to door-plate 1, the air-openings 9
and slots 8, pierced through the door and lining, as specified.
E. W. VAN DUZEN.
Pp. Herbert & Co.,
67, Strand, W.C.,
Agents to Applicant.