Improvements in Furnace Grates.
Year: 1892

page_text: Date of Application, 12th Sept., 1892
Complete Specification Left, 8th July, 1893-Accepted, 19th Aug., 1893
PROVISIONAL SPECIFICATION.
Improvements in Furnace Grates.
I, RICHARD GOLL of 112 Eschersheimer Landstrasse Frankfort-on-the-Main, in
the Empire of Germany, Manufacturer, do hereby declare the nature of this
invention to be as follows:-
Hitherto in regulating the air supply of furnaces attention has only been directed
to the quantity and mode of conveying the air whilst neglecting to properly
distribute the current at the most advantageous points, for it has not been borne in
mind that the air flows to the various points of the grate with varying force, the
fresh air following the outflowing air in as straight a line as possible, generally
therefore in a straight line from the air door towards the combustion chamber or
into the fire tubes. It therefore tends to pass obliquely through the centre of the
grate which lies in the direct path of draught where there is a prejudicial excess of
air whilst there is insufficient air in the neighborhood of the fire door. Conversely
under certain conditions the stronger current may be at the front or rear whilst
there is insufficient air at other points.
This invention consists in means whereby to distribute the air current uniformly
or in an otherwise advantageous manner over the whole grate surface and partially
divert it from that point of the grate at which it tends to predominate. The
contrivances serving this purpose may be placed either between the separate
furnace bars, in the furnace or directly below it. In either case their function is
to distribute the air arriving at the various points of the lower surface of the grate
in variable quantities, so that it is properly distributed over the various points of
the grate surface i.e. so that on the whole it emerges uniformly distributed. The
distribution or division of the air current is effected either by means of baffles or
obstructions placed in its path to divert the draught from the point where it is
strongest, or by forcing the air entering beneath the grate over a surface of a limited
area, to emerge from the grate surface over an area of different magnitude, or to
serve various areas, covered with coal. The simplest means of carrying out the first
method consists in providing wings or projections between the bars against which
the air impinges. The simplest form of carrying out the second method consists in
dividing the interstices between the bars so that the areas of the apertures at which
the air enters and emerges varies at the different points, or by varying the
proportion of the lower to that of the upper cross-section along the bar. In practice
it will often be found advantageous to combine the three modes, so that the air
passages of the grate are divided into compartments on the sides whereof, formed by
the intermediate wings, the air impinges, the compartments at the same time being
of different area at the under and upper side owing to the inclination of these wings.
or the alteration of the cross section of the grate bar. For the throttling of the air
current at several points of the grate, an increase of the friction may be substituted
by making the air passages of suitable form. Furnaces are frequently required to
work under variable conditions, when therefore the air supply is effected by special
apparatus independent of the grate bars, it is often desirable to make them movable
and capable of being regulated for varying conditions.
Reference is to be had to the accompanying drawings, forming part of this
Specification, wherein
Figures 1 to 4 shew grate bars on which lateral vertical wings have been cast,
extending from one bar to the next. They are of different depths at different parts
of the bar, as in Figures 1 to 3, or situated at different heights between the bars, as
in Figure 4, so as to modify the conditions of the entrance of the air current into
the spaces between them.

page_text: Figure 5 shews similar parallel wings set obliquely, against which the draught
impinges almost at right angles, so that the central wings where the draught is
strongest offer most resistance and check the current which is diverted and caused
to flow between the wings towards the front end of the bars.
Figures 6 and 7 shew the wings arranged converging and diverging, increasing
or decreasing the air current in the middle of the grate.
Figure 8 shews the wings or baffles so mounted as to be adjustable by being
oscillated upon axes and set by means of rods.
Figure 9 shews wings or baffles made separately, inserted in the spaces between
the bars from below.
Figures 10 and 10 shew a removable wing or baffle hooked at the upper part
and hung in a notch in the grate bar.
Figures 11 to 13 shew plan views of the grate bars shewn in Figures 1 to 7 from
which it will be seen that the wings or baffles cast on one side of the bars may be
alike on all the bars, as in Figures 11 and 12, or be cast on both sides, plain and
winged grate bars or parts thereof being juxtaposed alternately, as in Figure 13.
Figure 14 shews the equivalent of the wings, the grate bar being constructed as
shewn or in the form of vertical prisms of variable depth.
Figures 15 and 16 shew the wings or projections placed obliquely and bent, with
intermediate wings which at same time serve the purpose of baffles.
Figures 17 and 18 shew how the same end may be attained by making the wings
or projections of unlike thickness at the under and upper side of the grate.
Figures 19 and 194 shew the different ways of narrowing the inlet cross-section
of the air-channels by means of specially shaped castings.
Figures 20 to 20B shew an elevation section and underside plan of a grate bar
having a longitudinal rib at each side of its web, of greatest thickness at the middle
of the bar and tapering off towards the ends, which diminishes the flow of air in the
centre and diverts it towards the ends of the bar.
Figures 21 and 21ª shew the same rib or web in an arched form which without
being tapered effects the same result, owing to the wedge-shaped cross-section of
the grate bar.
Figures 22 to 224 shew arrangements in which, by the variable cross sectional
area of the bar, the interstices being uninterrupted, the passage of the air there-
through at the various points thereof is regulated, the grate being cast in one with
the bars of the different sections shewn in Figure 22 at the different points a—b;
c-d; e-f; so that whilst the interstices remain unaltered at the upper side, they
vary in width at the lower side, of the grate.
Figures 23 to 23ª shew a zig-zag grate bar whereof the interstices are of uniform
breadth and afford like conditions for the passage of the air, but in which the area
of the surface of the bar varies so that the relation of the free to the covered grate
surface alters, whereby the access of air is regulated.
Figures 24 and 24 shew the same alteration of the relation between the free and
the covered grate surface with a hollow bar but with various kinds of openings at
different points.
Figure 25 shews the alteration of the relation of the covered to the free grate
surface by casting lateral pieces of various areas on the bar and the provision of
an air distributor separated from the bar which acts like the wings described in
Figure 6.
Figure 26 shews a second arrangement of such an air distributor separated from
and placed beneath the grate.
Figure 27 shews a grate with movable wings.
Figure 28 shews a grate in which the wings are replaced by a prolongation of
individual bars downwards.
Dand this 10th 1
1
1000

page_text: COMPLETE SPECIFICATION.
Improvements in Furnace Grates.
I, RICHARD GOLL of 112 Eschersheimer Landstrasse Frankfort-on-the-Main, in
the Empire of Germany, 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 :-
Hitherto, in regulating the air supply of furnaces, attention has only been
directed to the quantity and mode of conveying the air whilst neglecting to
properly distribute the current at the most advantageous points, for it has not been
borne in mind that the air flows to the various points of the grate with varying
force, the fresh air following the outflowing air in as straight a line as possible,
generally therefore in a straight line from the air door towards the combustion
chamber or into the fire tubes. It therefore tends to pass obliquely through the
centre of the grate which lies in the direct path of draught where there is a
prejudicial excess of air whilst there is insufficient air in the neighborhood of the
fire door. Conversely under certain conditions the stronger current may be at the
front or rear whilst there is insufficient air at other points.
This invention consists in means whereby to distribute the air current uniformly
or in an otherwise advantageous manner over the whole grate surface and partially
divert it from that point of the grate at which it tends to predominate. The
contrivances serving this purpose may be placed either between the separate
furnace bars, in the furnace or directly below it. In either case their function is
to distribute the air arriving at the various points of the lower surface of the grate
in variable quantities, so that it is properly distributed over the various points of
the grate surface-i.e. so that on the whole it emerges uniformly distributed. The
distribution or division of the air current is effected either by means of baffles or
obstructions placed in its path to divert the draught from the point where it is
strongest or by forcing the air entering beneath the grate over a surface of a
limited area, to emerge from the grate surface over an area of different magnitude,
or to serve various areas covered with coal. The simplest means of carrying out
the first method consists in providing wings or projections between the bars against
which the air impinges. The simplest form of carrying out the second method
consists in dividing the interstices between the bars so that the areas of the
apertures at which the air enters and emerges varies at the different points, or by
varying the proportion of the lower to that of the upper cross-section along the bar.
In practice it will often be found advantageous to combine the three modes, so that
the air passages of the grate are divided into compartments on the sides whereof,
formed by the intermediate wings, the air impinges, the compartments at the same
time being of different area at the under and upper side owing to the inclination of
these wings or the alteration of the cross-section of the grate bar. For the
throttling of the air current at several points of the grate an increase of the friction
may be substituted by making the air passages of suitable form.
Furnaces are
frequently required to work under variable conditions, when therefore the air supply
is effected by special apparatus independent of the grate bars it is often desirable
to make them movable and capable of being regulated for varying conditions.
Reference is to be had to the drawings accompanying the Provisional Specifi-
cation, wherein
Figures 1 to 4 shew grate bars on which lateral vertical wings have been cast
extending from one bar to the next. They are of different depths at different parts
of the bar, as in Figures 1 to 3, or situated at different heights between the bars,
as in Figure 4, so as to modify the conditions of the entrance of the air current
nto the spaces between them.
Figure 5 shews similar parallel wings set obliquely, against which the draught
mpinges almost at right angles so that the central wings where the draught is

page_text: strongest offer most resistance and check the current which is diverted and caused
to flow between the wings towards the front end of the bars.
Figures 6 and 7 shew the wings arranged converging and diverging increasing or
decreasing the air current in the middle of the grate.
Figure 8 shews the wings or baffles so mounted as to be adjustable by being
oscillated upon axes and set by means of rods.
Figure 9 shews wings or baffles made separately, inserted in the spaces between
the bars from below.
Figures 10 and 10 shew a removable wing or baffle hooked at the upper part
and hung in a notch in the grate bar.
Figures 11 to 13 shew plan views of the grate bars shewn in Figures 1 to 7 from
which it will be seen that the wings or baffles cast on one side of the bars may be
alike on all the bars, as in Figures 11 and 12, or be cast on both sides, plain and
winged grate bars or parts thereof being juxtaposed alternately, as in Figure 13.
Figure 14 shews the equivalent of the wings, the grate bar being constructed as
shewn or in the form of vertical prisms of variable depth.
Figures 15 and 16 shew the wings or projections placed obliquely and bent, with
intermediate wings which at same time serve the purpose of baffles.
Figures 17 and 18 shew how the same end may be attained by making the wings
or projections of unlike thickness at the under and upper side of the grate.
Figures 19 and 19 shew the different ways of narrowing the inlet cross-section
of the air channels by means of specially shaped castings.
Figures 20 to 20B shew an elevation, section, and underside plan, of a grate bar
having a longitudinal rib at each side of its web of greatest thickness at the middle
of the bar and tapering off towards the ends, which diminishes the flow of air in the
centre and diverts it towards the ends of the bar.
Figures 21 and 21 shew the same rib or web in an arched form which without
being tapered effects the same result, owing to the wedge-shaped cross-section of
the grate bar.
Figures 22 and 22 shew arrangements in which by the variable cross-sectional
area of the bar, the interstices being uninterrupted, the passage of the air
therethrough at the various points thereof is regulated, the grate being cast in one
with the bars of the different sections shewn in Figure 22 at the different
points a-b; c-d; ef; so that whilst the interstices remain unaltered at the
upper side they vary in width at the lower side of the grate.
Figures 23 and 23ª shew a zig-zag grate bar whereof the interstices are of
uniform breadth and afford like conditions for the passage of the air, but in which
the area of the surface of the bar varies so that the relation of the free to the
covered grate surface alters, whereby the access of air is regulated.
Figures 24 and 24 shew the same alteration of the relation between the free and
the covered grate surface with a hollow bar but with various kinds of openings at
different points.
Figure 25 shews the alteration of the relation of the covered to the free grate
surface by casting lateral pieces of various areas on the bar and the provision of an
air distributor separated from the bar which acts like the wings described in
Figure 6.
Figure 26 shews a second arrangement of such an air distributor separated from
and placed beneath the grate.
Figure 27 shews a grate with movable wings.
Figure 28 shews a grate in which the wings are replaced by a prolongation of
individual bars downwards.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1st. The herein described means for regulating the air supply to furnace grates,
consisting in the employment of bars so constructed that the incoming current of

page_text: air shall meet with varying resistances and be either distributed over the whole
grate surface, or to any desired part thereof, substantially as specified.
2nd. Constructing grate bars for furnaces with wings or baffles which offer
varying resistances to the draught, so as to divert it as required.
3rd. Providing the grate with air passage ways having different areas for the air
inlet and outlet, as and for the purpose specified.
4th. Constructing grate bars with cross-sections so that the proportion of the
lower width of joint to the upper varies.
5th. The combination, with the grate bars, of movable air way wings or baffles,
as described.
6th. The arrangement of a separated air way as above specified (1 to 6) directly
beneath the grate.
7th. The particular shape of the arrangement characterized by Claim 3,
consisting of wings which by their curvature contract the lower inlet aperture of
the air channel formed by them.
8th. The particular construction for effecting the object referred to in Claim 7
in which the wings are either thickened or special pieces inserted.
9th. Regulating the air supply by altering the proportion of the covered and the
free grate surface at different points of the bars with uniform width of joint.
10th. The construction of grate bars with heads or projections at different
heights for the purpose specified.
.
11th. In transverse grates, the arrangement of separate bars projecting
downwards.
12th. The improved forms of the grate bars described and shewn in the drawings,
individually or in combination, for the purpose specified.
Dated this 8th day of July 1893.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.