IMPROVEMENTS IN SELF-CLEANING FURNACE GRATES
Year: 1884

page_text: I, GEORGE GATTON MELHUISH HARDINGHAM, of 191, Fleet Street, in the
County of Middlesex, Civil Engineer and Patent Agent, do hereby declare the
nature of the said invention for "IMPROVEMENTS IN SELF-CLEANING FURNACE
GRATES," 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 that class of grates in which rocking grate bars are
used, and the invention consists in pivoting or journaling the bars in different
planes, so that when the bars are moved or rocked they shall have a differential
movement, whereby some of the bars shall be made to move in the arc of a larger
circle than others, thus moving a greater distance and varying the spaces between
them and the other bars, all as hereinafter more fully set forth.
The accompanying drawings form a part of this specification and represent what
I consider the best means of carrying out the invention.
Figure 1 is a side elevation of a grate embodying my invention.
Figure 2 is a similar view, with a portion of the frame broken away.
Figure 3 is a top plan view of the same.
Similar letters of reference indicate like parts in all the figures where they
occur.
Grates have long been made with their bars arranged to rock or oscillate in
various ways, but so far as I am aware, in all such cases the movable bars have
been arranged so as to have a uniform movement; that is to say, the bars all
moved the same distance and retained the same relative position to each other.
My invention differs from all such in that the bars are so arranged that when they
are simultaneously moved a portion of them will oscillate or rock through the arc
of a larger circle than the others, thus moving a greater distance, and vary the
width or spaces between them and the adjoining bars.
In the drawings D indicates the grate bars, which are provided with journals at
their ends, so they can be pivoted in a suitable frame or supports in such a
manner as to freely rock to and fro.
These bars are provided along their upper surfaces with a series of projections of
any suitable form for supporting the coal and crushing or breaking up the clinker,
and each having a vertically depending arm by which they are all connected to a
rod or bar B by which they can be simultaneously moved or shaken, as is usual in
this style of grates. These bars I prefer to arrange transversely to the frame,
though they may be arranged longitudinally if desired. They may be mounted, as
shown in figures 1 and 2, in a frame provided with legs, so that the device as a
whole can be set in the fire chamber; or the bars may be simply journaled in two
side bars secured in the chamber, as preferred.
These bars, instead of having their journals located at a uniform distance from
their top or upper surface, are made in two series or sets, one set having their
journals located considerably further from the top of the bar than are those of the
Din A31

page_text: other set, as indicated in Figure 1 in which A¹ indicates the journals of one set
and A the journals of the other set of bars:
In mounting these bars in their frame, I so arrange them that their upper
surfaces shall all be in the same horizontal plane, or substantially so, and conse-
quently the holes or bearings for their journals will be arranged in two different
planes, one higher than the other as represented in figures 1 and 2.
The result of this construction and arrangement is that those bars which have
their journals placed in the lower plane will move through the arc of a much larger
'circle than the others, and will consequently move much farther.
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By this increased movement these bars will swing away from the adjoining bar
on one side over towards the adjoining bar on its opposite side when moved in one
direction, and will reverse the operation when moved in the opposite direction, thus
oscillating or moving to and fro between the adjoining bars. This movement
raises the clinker, coal and ashes, breaking up the former and sifting out the latter,
and the increased or enlarged spaces thus formed at intervals afford increased
facility for the escape of both ashes and clinker.
I have shown the bars of. the two sets arranged alternately in regular order, but,
it is obvious that this order may be varied without departing from the spirit of my
invention; the gist of which is in so arranging or pivoting the bars as to impart to
them a differential movement as described.
The horizontal bar B is arranged to project at the front and is connected to a
pivoted lever, by which all the bars are moved simultaneously, and more or less as
may be desired."
It will be observed that by this peculiar method of pivoting the bars in different
planes, those which have the greater movement will drop below the others as they
approach the extremity of their movement in either direction, thus causing them
to rise and fall more than the intervening bars, thus tending to lift and break up
any crust or sheet of clinker that may form in the fire. This movement also tends
to shake up the mass of coal resting on the bars and more effectually shake and
sift out the ashes.
As the arms of those bars which have their journals arranged in the lower plane
will necessarily move in the arc of a smaller circle than the others, provision must
be made therefor, which is easily done by making vertical slots in the bar or in the
arms for the connecting bolt or stud to work in.
In practice I construct the arms with a horizontally projecting stud or wrist
which engages in holes in the bar B; and in such case it is only necessary to
elongate vertically those holes in which the studs of the lower journaled bars.
engage.
.
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 composed of a series of rocking bars, a portion of which shall be
pivoted in a horizontal plane while the remaining portion shall be pivoted in
another and different plane parallel with the first, substantially as shown and
described.
2. A grate composed of a series of bars, a portion of which shall have a
differential movement in relation to the other bars of the series, substantially as
and for the purpose set forth, whereby some of the bars shall be made to move in
the arc of a larger circle than the others.
Dated this 21st day of January, 1884.