Improvements in Shaking and Chopping Grates for Marine、 Boilers.
Year: 1897

page_text: Date of Application, 4th-May, 1897-Accepted, 26th June, 1897
“COMPLETE SPECIFICATION.
Improvements in Shaking and Chopping Grates for Marine、
Boilers.
I JAMES REAGAN, of the City and County of Philadelphia, State of
Pennsylvania, U.S.A., 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 shaking grates for marine or internally fired boilers, and
more particularly to that form or construction of grate, in which a series of movable
hollow choppers or shakers and intervening longitudinal apertured fire or grate
bars are employed. The office of the choppers being to clean or dump the fire,
while the apertured fire bars, which remain loose in position and take the place of
fixed water bars, are arranged to support or bridge the upper portion of the fuel
to prevent the choppers breaking through the top crust when they are agitated to
shake out the ashes or dirt in the lower part of the fire.
The object of my present invention is to dispense with the fastening device
consisting of split keys driven through openings in the depending lugs of the
choppers to impinge the lower sides of the rocking shafts upon which they are
mounted, as described in former patents granted to me, and substituting therefor a
simple, economical and effectual device, whereby the choppers can be readily placed
in position with the expenditure of a small amount of labor and time, and in case
any of them should become damaged while in the furnace it can be easily and
quickly removed and a new one substituted, without dismantling the grate or
interfering with the fire to any great extent. This will be found of especial
advantage in grates for furnace of marine boilers, where the space to work in
is limited and time of great importance.
The object of my invention is also, to provide a hollow bar having a curved
upper surface and apertures for the admission of air to the fire; by thus allowing
air to circulate freely through the interior of the bar, all danger of its burning
out or becoming warped or twisted by the heat of the fire, is avoided, and at the
same tine sufficient air is permitted to pass through the orifices at the top and into
the fire to insure a thorough combustion of the fuel, in the same manner as the
hollow choppers.
Reference being had to the accompanying drawings, in which :-
Figure 1, is a perspective view of my improvements in shaking and chopping
grates for marine boilers with the right hand side bars removed.
Figure 2, is a side view of a chopper or shaker einbodying my improvements.
Figure 3, is a side view of a chopper showing the device for connecting the pull.
and tie bars, by which the choppers are actuated.
Figure 4, is a sectional plan view on the lines V-V, of Figure 3.
Figure 5, is a longitudinal section of a grate with apertured fire bars extending
parallel, and choppers placed therebetween.
Figure 6, is a transverse section of the grate, showing the manner of applying
and removing the chopper to and from the angular rocking shaft.
Figure 7, is an end view of one of the square rocking shafts.
Figure 8, is a side elevation of a fire bar embodying my improvement.
Figure 9, is a plan view of the same.
Figure 10, is a vertical section through the longitudinal centre of same.
Figure 11, is a transverse sectiou, enlarged on the line X-X of Figure 9

page_text: Figure 12, is an end view of two fire bars or grate bars in position, with movable
choppers placed therebetween, showing the manner of supporting the same.
Figure 13, is a side view of a portion of a side and fire bar with the upper
portion sloped towards the fire to prevent ashes accumulating thereon.
The chopper 1, Figures 1 and 2, is made hollow from end to end and each side
at the upper portion has inside and outside projections or ribs, arranged in a
staggered or zig-zag order, to form air spaces to admit a uniform volume of air
throughout its entire length to insure thorough combustion of the fuel. One end
of the chopper is made are-shaped in order to co-act with arc-shaped ledges on
the front and rear bearing bars and similar ledges on the central bridge bar as
shown in Figures 1 and 5.
The choppers are provided with lugs 2, depending from the bottom thereof,
with an intervening open space, 3, which communicates with an aperture, 4, made
transversely through the centre of the chopper to accommodate the angular rocking
shaft 5, upon which the choppers are mounted.
The aperture 4, instead of being made square with four right angles is made
with four similar to a diamond or rhombus, the acute angles of which fit the
salient angles of the rocking shaft. The two upper sides 6, of the said aperture 4,
form tapering seats for the shaft, and the two lower sides 7, on each side of the
opening 3, form shoulders to impinge the lower sides of the shaft, to prevent dis-
placement, so that when the chopper is passed over the projecting angles of the
shaft, it will rest upon the upper faces of the same; and owing to sides, 6, of the
aperture 4, being inclined it will adjust itself in a vertical position between
the fire bars. At the upper or converging points of the sides, 6, a small recess, 8,
is made to allow clearance for the sharp corner or angle of the shaft, to avoid any
possibility of the chopper riding on this point and to insure a perfect seating on
the sides 6.
The shafts or bars 5, Figures 1, 5, 6, and 7, have end journals which drop into
bearings in the side bars 9, and an intermediate short cylindrical portion or round
spot 10, over which is passed the depending lugs, 2, of the chopper as shown in
Figure 6.
The choppers thus constructed are slipped one at a time, over the cylindrical
portion 10, of the rocking shaft and moved laterally into position, and the fire bars
dropped in place between each row of choppers. In case one or more of the
choppers should become damaged from any cause while under the fire it or they
can be readily removed by uncovering the fire and lifting out one or more fire
bars, as the case may be and sliding the chopper along until it is opposite the
round spot 10, on the shaft, at which point it is lifted out and a new one inserted,
moved to its proper position, and the fire bars replaced.
The chopper 11, which is a modification of chopper 1, has attached the bars for
shaking and dumping and is provided with depending lugs, 12, of increased
length in order to obtain the proper length of leverage to manipulate the grate.
Across the lower ends of the lugs, is bolted a pivot supporting plate 13, which is
made with an offset 14, on one side to enter the open space 3, and a similar
offset 15, on the opposite side to keep the pull bar 16, clear of the chopper and
also to lend additional support to the pivot pin 17, which passes through the
centre. In these choppers with long lugs the pull bars will have to be dis-
connected before the choppers can be removed.
The grate or fire bar, 18, Figs. 1, 8, 9, 10, is made of any convenient length
and width with round or curved top, and consists of side wings 19, with the open
space 20 between them bridged at proper intervals as shown at 21, Fig. 9 to
prevent lateral deflection and lend additional stiffness to the entire bar. The
opon space 20, thus formed in the longitudinal direction of the bar extends from
bottom to top and to within a short distance of each end at which point the
metal remains solid to further increase the strength of the bar, as shown at 20,
Fig. 10.
The interval open space 20 between the bridges 21, and ends 22, is further

page_text: divided into numerous small openings 24, by means of alternate teeth, 25, Figs. 9
and 11 formed on the inner sides of the wings 19 which project inwardly to
within a short distance of the centre, at which point their edges extent down-
ward vertically a short distance and then incline upwards sharply for the
remainder of their depths, to the lower edges of the wings.
The side teeth 25, are arranged in staggered or zig-zag order, that is the edge
or point of one tooth is opposite the space 24, on the opposite side as shown in
Figure 9, by thus distributing the air and causing a free circulation to every part
of the bar it is fully protected from burning out, becoming warped or twisted, and
owing to the upper surface including the teeth of the bar being curved, ashes are
prevented from accumulating.
It will be seen on referring to Figure 11, that the inner sides of the wings 19,
between the teeth 25, are sloped inwardly at the upper part at an angle of 60° for
a short distance, to the points 27, and then inclined towards the bottom edges; the
object being to increase the thickness of metal where it is most needed for strength
and at the same time increase the depth of the opening or apertures 24 so as to
direct the current of air as nearly on a line with the top of the choppers as
possible, when the bars are in position as above in Figure 12. The object in
slanting the upper edges at an acute angle, is also to prevent ashes lodging and
filling up the openings 24.
The teeth 25, form fuel supporting points, and in proportioning the air spaces or
openings 26 care should be exercised to have them of such area as to permit
sufficient air to pass through and furnish the proper amount of oxygen to the fire,
and at the same time prevent waste of fuel.
The bridges 21, previously mentioned, and shown in Figure 10, are made
tapering, being wide at the bottom and narrow at the top in order to present thin
edges at the fuel supporting points to avoid. the accumulation of ashes or other
refuse matter and they may consist of two or more according to the length of
the bar.
The bar 18, is recessed at one end to accommodate to the overlapping portion of
the adjacent bar, to permit a hoe to pass over and is supported upon suitable lugs
formed on transverse bearing bars extending the width of the furnace, with lugs 28,
depending from the extremities to engage the recesses formed in the ledges or lugs
of the transverse bridge and bearing bars.
The bar 9, Figure 13, which has a double function of side bar and fire bar is
made to slope or incline at any suitable angle at the upper portion, to allow ashes
to slide off when the choppers are agitated to prevent the formation of clinkers
along the sides or sheet of the furnace.
I have described the improvements which I have invented as being applicable
to furnaces of marine boilers, they can if so desired be applied with equal facility
to the furnace or fire box of stationary or locomotive boilers.
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
1st. A chopper or shaker 1, having depending lugs, 2, diamond or lozenge shaped
apertures 4, recess 8, and opening 3, in combination with the angular shaft or
bar 5, having end journals and intermediate cylindrical portion 10, substantially as
specified.
2nd. A chopper or shaker having a transverse opening 3, and aperture 4,
composed of the sides 6, and 7, forming a diamond or rhombus, in combination
with the angular portion of the shaft or bar 5, substantially as specified.
3rd. A chopper or shaker 11, having depending lugs 12, opening 3, and diamond
shaped aperture 4, in combination with the shaft 5, plate 13, bolt 17 and pull
bar 16, substantially as specified.
4th. A hollow grate or fire bar 18, with staggered arrangement of internal
teeth 25, forming air spaces 24 and bridges 21, substantially as set forth.

page_text: 5th. A hollow grate or fire bar 18, consisting of the side wings 19, bridges 21,
closed ends 22, lugs 28, and staggered arrangement of teeth 25 on the inner sides
of the wings between the bridges and ends of the bar, substantially as described.
Dated this 4th dox of Nar 1807
ALLISON BROS.,
Agents for the Applicant.