Improvements in Furnace Grates.
Year: 1892

page_text: Date of Application, 3rd May, 1892-Accepted, 4th June, 1892
COMI DEI DI MUITI
[Communicated from abroad by WILLIAM RUFUS RONEY, of No. 620, Atlantic
Avenue, Boston, Massachusetts, United States of America, Mechanical
Engineer.]
Improvements in Furnace Grates.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake, & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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 :-
This invention relatos to that class of inclined furnace grates consisting of a
series of horizontal, transversely arranged grate bars, having flat top surfaces to
receive the fuel, and depending webs or flanges for giving stiffness to the bars.
This invention embraces as one of its principal features, a construction in grates
of the character referred to by which the depending flanges of the bars are provided
with longitudinal slots arranged opposite or in line with the horizontal openings or
spaces in or between the bars, so that a "slicing bar" or other suitable implement
may be inserted from the front of the grate through said slots and through or
between the grate bars for the purpose of stoking or stirring the mass of coal
upon the grate.
The invention also embraces an improved construction by which the upper parts
of the bars are inclined and provided with longitudinal apertures extending longi-
tudinally through the inclined top or supporting faces thereof to the rear or outer
surfaces, and in which longitudinal slots in the depending flanges are arranged
opposite the said slots or longitudinal apertures in the upper parts of the bars.
By this construction a slicing bar or other suitably shaped tool may be inserted
from the front of the grate through the slots in the depending flanges and also
through the slots in the depending flanges and also through the slots or openings in
the upper parts of the bars for the purpose of stoking or stirring the fire, and at
the same time of removing any adherent clinkers or masses of fuel which attach
themselves to the surfaces of the bars.
The grate bars shown herein are rocking grate bars, and automatic feed devices
will commonly be used in connection with such rocking grate bars for continually
moving or actuating the same so as to produce a practically continuous feed of the
fuel downwardly along the inside surface of the grate. A grate provided with
bars made as herein set forth may be employed with advantage when such actuating
devices are used, inasmuch as it may often be found desirable to insert through the
bars a slicing bar or other tool to loosen or remove the clinkers or masses of the
latter which accumulate on the grate, even when a rocking motion of the grate
bars is relied upon for feeding the fuel downwardly along the surface of the grate.
A grate embracing the improvements herein described may, however, be used with
advantage in a stationary or non-rocking grate, it obviously being practicable,
especially in the case of small grates, to properly feed the fuel downwardly along
or over the inclined grate by agitating the fuel by the use of a hand tool inserted
through the slots or openings provided for the purpose. In many cases, however,
it may not be found necessary to use grate bars constructed in accordance with the
present improvement throughout the entire length of the grate, as, for instance,
owing to the fact that the clinkers are more likely to accumulate where the fire is
hottest, to wit, at the lower part of the inclined grate, the grate bars constructed
in accordance with the present invention may be employed at the lower part of the
grate, and similar grate bars but without slots in their upper surfaces may be
employed in the upper part of the grate, and a construction of this kind is illustrated
in the accompanying drawings.

page_text: As a further improvement in grates of the general character referred to,
provide actuating devices for the rocking grate bars which give a greater rocking
movement to the bars in that part of the grate where the most rapid downward
movement is desired, it having been found in practice that in some kinds of coal a
more rapid movement of the fuel downward over the grate is desirable at one part
of the grate than at another.
In the accompanying drawings illustrating my invention:
Figure 1 is a central vertical section of a furnace grate constructed in accordance
with my invention.
Figure 2 is a detail cross-section of the same taken upon line 2-2 of Figure 1.
Figure 3 is a plan view of the grate bar shown in Figure 2.
Figure 4 is a detail sectional view corresponding with Figure 1 and illustrating
a modification.
Figure 5 is a similar detail sectional view, showing the lower set of grate bars of
Figure 1 in a different position.
Figure 6 is a sectional view of a grate, showing the reciprocating bar by which
rocking motion is given to the grate bars constructed to give a greater extent of
movement in one part of the grate than in another.
As illustrated in said drawings, A, A, are the side walls of the furnace, and B
the front wall thereof. C indicates as a whole an inclined grate arranged within
the furnace, and D an inclined plate located over the uppermost bar of the grate C
and upon which the fuel is delivered through a passage, d, in the front wall of the
fire box, either by hand or by an automatic feeding device. E is a horizontal
dumping grate, located at the rear of the inclined grate C, and E¹ a rod for
operating said dumping grate.
The grate C herein illustrated is composed of two sets of transverse, horizontally
arranged grate-bars, the set, c, c, c, forming the lower part of the grate, while the
set, c, c, c, forms the upper part thereof. All of the grate bars to both sets are
provided at their ends with bearings or trunnions, c², c³, which rest in notches, f,f,f,
in the upper edges of stationary inclined supporting bars, F, F, which are secured
against the opposite side walls of the furnace. All of said grate bars, furthermore,
are provided with longitudinally slotted webs or flanges, c³, c³, acting to give stiff-
ness to the bars, and with top surfaces on which the fuel rests, the front and rear
edges of the bars being continuous or non-fingered, while the bars are arranged in
a stepped position so that the rear edge of one bar is adjacent to but somewhat
distant from the edge of a subjacent bar; vertical spaces being thus provided
between the adjacent edges of the bars to allow the necessary openings for the
influx of air.
In the particular construction illustrated the grate bars are hung in such manner
as to enable them to be rocked or oscillated, and for the purpose are provided with
depending arms, c, c, which engage with notches, 9, in a reciprocating rod or
bar, G, which bar is adapted for endwise movement in a manner to rock the grate
bars in their bearings on the supporting bars F. An actuating rod, G', is attached
to the bar G and serves as a means for communicating motion to said bar G from
an external actuating device, giving endwise reciprocatory motion to the bars.
As hereinbefore stated, however, the employment of means for rocking the grate
bars is not essential as far as the present invention is concerned. When devices
are employed for rocking the bars, however, the fuel placed upon the inclined
grate is carried along or down over the grate bars during the process of combus-
tion through the rocking movement of the several grate bars.
The several grate bars c c c at the lower part of the grate are shown as somewhat
inclined upon their top surfaces in the same direction as the general inclination of
grate, but at a less inclination than that of the grate, so that several bars form' in
effect a series of steps, the top surfaces of which, however, are inclined instead of
being horizontal. In the upper part or body of each bar above the depending
flange thereof is formed a series of longitudinal and horizontal slots or openings, c,
arranged parallel with the edges of the bar and extending from the outer or rear

page_text: surface thereof through the inclined top surface of the grate in a generally horizontal
direction, the rear or lower opening of the said slot or aperture being located at the
junction of the depending flange with the body of the bar, so that the said aperture,
or opening extends from the rear or outer surface of the flange and over the top of
the same to the supporting surface of the grate bar. The depending flange of each
bar c c c is also slotted and the slots, c, therein are arranged horizontally opposite
the openings or apertures c which are formed in the body of the bars, as above
described. From this arrangement of the slots or openings in the webs or flanges;
it is obvious that notwithstanding the fact that the flange of each grate bar extends
downwardly past the next adjacent grate bar, said slots afford a means of inserting
from the front of the grate a tool or implement which may be thrust through the
slots for the purpose of stirring the fuel resting on the grate or removing
clinkers from the surfaces of the grate bars. In the case of rocking grate bars such
as those shown, the slots or openings, c, are made wide enough to permit the
insertion of the slicing bar or other implement when the grate bars are inclined a
well as when they are horizontal. For the same purpose the slots or apertures (³
are shown as made wider at the outer or rear surface of the grate bar than at the
top or inclined surface thereof, so that the oscillatory motion of the grate will
not prevent the insertion of a poker or other implement through said slot or
aperture.
As herein shown the flanges of the bars c c c are relatively narrow, the drawing
showing them much narrower than those of the bars c c c¹, the number of slots or
openings employed depending on the vertical depth of the webs or flanges which
may be varied in number according to the length of the grate bars and the strength
or stiffness required therein.
The employment of the longitudinal slots or apertures c has the advantage not
only of affording access to the supporting surface of the grate bars from the front of
the grate, but they admit of a better supply of air to support combustion and
facilitate the cooling of the grate bars and thereby lessen the liability of the clinker
becoming fused and adhering to the bars by the excessive heating or fusion of the
metal composing the bars. It will, of course, be understood that the said slots or
openings e enable the attendant to properly stir the fire by a hand implement
and also when necessary to aid the downward movement of the fuel and clinker
over the grate bars toward the bottom of the grate.
The slots or openings c³ in the bars, and also the slots c in the depending flanges
of the bars are not shown as extending continuously the full length of the grate bars,
but intermediate connecting pieces are present to connect the longitudinal parts of
the bars and flanges with each other so that the bar as a whole is made sufficiently
strong and rigid. It is, of course, understood, however, that the number and
location of these connecting pieces is immaterial and that any construction may be
employed adapted to give sufficient strength and rigidity to the bars. It is, further-
more, unnecessary that each grate bar should be cast or formed in a single piece,
and the bars may be constructed with suitable slots or openings of proper shape to
produce the results herein described when made either of cast or wrought metal,
and when made in one or more parts or pieces.
It is obviously practicable to employ the novel construction above described in
connection with grate bars which are also constructed to provide for the insertion
of a slicing bar or poker horizontally between the adjacent margins of the bar, as
illustrated in the case of the bars c¹, c', c', of Figure 1. Such construction is illus-
trated in Figure 4 wherein grate bars cc'c' are shown having horizontal slots or
apertures c³ extending from front to rear and through the inclined upper surfaces of
the grate bars, as hereinbefore described, with slots c in the depending flanges
arranged horizontally opposite said openings cc, and other intermediate slots of
openings, c, e, arranged opposite the spaces between adjacent grate bars to allow
the insertion of a slicing bar through said spaces as well as through the said
openings co.
It will be noted that the grate bars c c c shown in Figure 1 as embodying my

page_text: improvement, while arranged to overlap each other in order to avoid leaving vertical
spaces between the bars, are so constructed at their adjacent edges that the rear.
edges of the lower bars may be moved upwardly past the forward edges of the
upper ones in the manner indicated in Figure 5, which shows the changed position
of said bars at the limit of their movement, when rocked. The construction of the
bars so that their adjacent edges may be moved past each other, as above indicated,
is a desirable one for those parts of the grate at which the clinker is liable to form
in a solid mass, inasmuch as the rocking of the bars, in the manner described, greatly
facilitates the breaking up of the fused masses of fuel or clinker which are liable
to form over or in contact with the grate bars. It will be understood, however,
that this particular construction in the bars is not essential in all cases where the
bars are slotted or apertured in the manner herein described inasmuch as efficient
stoking may be accomplished and the clinker sufficiently broken up by the action of
the slicing bar or other tool inserted through said apertures or slots in the manner
heretofore described. It will also be understood that in the construction shown in
Figure 4, the breaking up of the clinker will be sufficiently accomplished by a tool
inserted through the apertures in the grate bars or through the spaces between the
same, the bars in that case not being adapted to be rocked past each other at their
adjacent edges.
It will be observed in connection with all of the forms of grate bars herein shown
and above described, that practically no spaces are provided through which fuel
may fall vertically through the grates; all of the spaces or slots through which the
stoking or stirring of the fuel is accomplished being arranged horizontally so that
the ashes or particles of fuel which fall from the advanced or lower edges of the
bars or from the upper edges of the openings therein will be caught by and rest
upon the horizontal surfaces below said edges. This construction is especially
important in the use of "slack" or fine coal for fuel. The grate illustrated in the
drawing, for instance, is more especially intended for slack coal and for this reason
more especially at the upper bars c¹ c¹ c¹ of the grate made horizontal and over-
lapping in the manner shown. The utility of this construction will be rendered
obvious when it is understood that the fuel is first heated and coked while resting
upon the upper grate bars c¹ c¹ c', which, as will be clearly seen from the drawings,
are so constructed as to prevent any part of the finest fuel from falling through the
same. After the fuel is coked, however, it loses its pulverulent character and the
particles are partially fused and adhere together so that in passing downwardly
over the grate they are not likely to fall through the spaces between the lower
grate bars c c c, except as it may escape in small quantities in the form of ashes.
The lower grate bars c c c while not being arranged to overlap so as to prevent
possibility of the escape of fine or granular fuel between them, are close enough
together to practically obviate liability of the downward escape of the burning
pieces or particles of fuel, while the openings through said bars being practically
horizontal, afford no openings for such downward escape of the fuel. It will, of
course, be understood, however, that in grates adapted for burning some kinds of
fuel all the bars may be made like the bars ccc or cel c¹ in Figure 1, or part of the
grate may be formed of bars of the kind illustrated and a part of the grate bars of
a kind unlike any herein shown.
In Figure 6 is shown a construction in the bars G G by which the rocking-plate
bars may be given a more extended movement at the lower than at the upper part
of the grate; this being the variation from a uniform movement most commonly
required. For this purpose the notches gg of the bars G are made, in the upper
part of said bar, considerably wider than the arms et c', so as to afford less motion
between said bar G and the arms at this point. The notches g g at the lower part
of the bar G are made of the same width as the said arms c c so as to engage the
latter at all times during the movement of the bar. The variation of the width of
the notches may be gradual from one end of the bar to the other, as shown, or there
may be several notches of each of two or more widths. It follows from this con-
struction that the grate bars at the lower part of the grate will be rocked to a greater

page_text: If
extent than at the upper part of the grate, with the result of feeding or carrying
forward the fuel more slowly at the upper than at the lower part of the grate.
desired, however, the reverse construction may be employed and the fuel fed more
rapidly at the upper than at the lower part of the grate.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me
by my foreign correspondent I declare that what I claim is:
1 An inclined grate consisting of horizontally arranged grate-bars, having
depending webs or flanges provided with longitudinal slots or openings.
2-An inclined grate consisting of horizontally arranged grate-bars having
inclined top surfaces and depending webs or flanges, said grate-bars having openings
or slots extending horizontally from their inclined faces to their rear or outer surfaces
and the depending webs or flanges being provided with longitudinal slots or openings
arranged opposite said slots or openings in the grate bars.
3: The combination, with an inclined grate consisting of a series of horizontal,
transversely arranged grate-bars, of a reciprocating actuating bar provided with
notches to engage the grate bars, said notches being of unequal widths to give the
bars a greater movement in one part of the grate than in another.
Dated this 2nd day of Nov 1800
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.