Improvements in connection with Fire Grates of Furnaces.
Year: 1894

page_text: Date of Application, 26th Jan., 1894-Accepted, 7th Aor., 1894
COMPLETE SPECIFICATION.
Improvements in connection with Fire Grates of Furnaces.
I, JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this invention (which has been com-
municated to me from abroad by Louis Marie Gabrielle Delaunay-Belleville of
58 bis Chaussée D'Antin Paris in the Republic of France Engineer) and in what
manner the same is to be performed to be particularly described and ascertained in
and by the following statement :—
This invention relates to certain improvements in connection with the fire grates
of furnaces and has reference more particularly to the rocking bars or grate
described in the Specification of Letters Patent dated 24th June 1892 No. 11808,
the object of the present invention being to provide means whereby the air for
supporting combustion is more evenly distributed below the bars and consequently
the combustion of the fuel improved and the durability of the bars increased.
I will describe the invention with reference to the accompanying drawings of
which Figures 1 to 6 show the construction and arrangements of the fire-bars and
apparatus as described in the Specification of Letters Patent No. 11808" herein-
before referred to and Figures 7 to 13 illustrate the improvements according to the
present invention.
Figure 1 of the drawings is a side elevation showing the arrangement of fire-bars
and bearer described in the Specification hereinbefore referred to and Figure 2 is a
section taken along the line X X (Figure 1).
Figures 3 and 4 are views at right angles to each other of the arrangement
described in the Specification before referred to for rocking the bars, Figure 4
being a section along line Y Y (Figure 3).
Figure 5 represents a sectional elevation taken along the line Z Z of Figure 6 and
Figure 6 is a corresponding plan of the arrangement of levers for supporting the
plates. For operating the bars as described in the Specification before referred to.
Figure 7 represents in side elevation a bearer for the fire-bars constructed
according to the present invention, Figure 8 being a transverse section along the
line XX' of Figure 7.
Figure 9 is a front elevation of one of the plates by which the bars are raised,
Figure 10 being a section along the line Y' Y' of Figure 9.
Figures 11 and 12 are views similar to Figures 5 and 6 representing the arrange-
ment of levers for supporting the plates for raising the fire-bars according to the
present invention, Figure 11 being a section along the line Z' Z' of Figure 12 and
Figure 13 represents a section along the line T T of Figure 12.
The transverse bearers A of the fire-bars B as shown in Figures 1 and 2 are
plain girders and prevent to a certain extent the air which enters the ash-pit with
considerable velocity, from having access to the adjacent surface of the bars
situated behind these bearers, whereas the bearers A. constructed according to the
present invention as shown in Figures 7 and 8 are perforated or so constructed that
the circulation of the air flowing to the grate is facilitated and its access to the part
of the grate situated immediately behind these bearers is ensured. The said bearers
as shown in the drawings (Figures 7 and 8) consist of an angle iron a the vertical
side of which carries the fire-bars B and an iron plate a' is arranged parallel to the
horizontal side of the angle iron a and connected thereto by flat plates a² forming
trellis work. The vertical side of the angle iron a is provided with perforations as

page_text: shown to allow of the passage of air which air also passes through the trellis work
of the bearers aforesaid.
The invention is not limited to the form or construction hereinbefore described,
for instance the bearers A may be constructed of cast steel or in any other suitable
manner. The bearers are supported at C C on the walls of the ash-pit and they
may also have a middle support C' if the width of the grate necessitates it.
When constructed in the manner described in the Specification before referred to
apart from the small volume of air which can pass through the recesses or slots
formed in the upper edges of the plates D (Figures 3 and 4), a large portion of the
grate contiguous to and at the back of the said plates receives little or no air
because the velocity with which the air enters the ash-pit carries the current past
and under the lower edges of the plates. In the improved arrangement illustrated
in Figures 9 and 10 the plates D are formed with openings d and the air passing
through these openings has easy access to the part of the grate situated immediately
behind the plates. The shoulders I, I form counter-weights and serve the same
purpose as those described in the Specification herein before referred to.
In the arrangement shown in Figures 5 and 6 the shaft E by which the fire-bars
are rocked is carried by two girders F fixed under the bearers A. These girders F
are shown in section in Figure 1. The shaft E is of iron of n section covered by
a sheet iron screen e which protects it from the heat of the fire and from contact
with the falling cinders but which also greatly impedes the circulation of the air.
The plates D are carried by the arms G, which are formed by two angle irons
placed back to back the horizontal portion of which forms an obstacle to the
passage of air.
In the arrangement according to this invention as illustrated by Figures 11, 12
aud 13, the shaft E for rocking the fire-bars consists of a hollow tube of square
section so placed that the hot ashes and cinders which fall through the grate cannot
lodge thereon. This shaft E is carried by two brackets or supports F fixed to the
walls of the ash-pit, but a third central support F' (Figure 13) can be employed if
necessitated by the width of the furnace.
The arms G for carrying the plates D may be constructed of wrought iron or
cast steel of small horizontal section as shown in Figures 9 and 13, but of sufficient
depth to give the required strength, and are shrunk on the shaft E.
The said shaft E is provided at its ends with cast steel caps or boxes H which
oscillate on knife edge bearings 2. This shaft E if made in two halves as shown
may be joined together at the middle by a coupling L carrying a 'forked lever. 1, 1
which is connected by means of a rod with another lever externally placed to the
furnace by means of which the bars are rocked. When there is a central support
provided owing to the width of the furnace the coupling L rests on a knife edged
bearing 3 fixed on the said support.
The combination and arrangement of parts hereinbefore described is very simple
and offers the minimum of obstruction to the circulation of the air and consequently
to its easy access to the whole of the lower surface of the grate, by which a more
effectual combustion of the fuel and increased durability of the bars are ensured.
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 :-
:-
1. In connection with the fire-grates of furnaces perforated bearers for the fire
bars constructed and arranged substantially as and for the purpose hereinbefore
described.
2. In connection with the fire grates of furnaces the combination of the plates D
and levers G, for supporting the said plates mounted on a rocking shaft working on
knife edge bearings 2 and means for operating the said shaft substantially as
herein before described with reference to Figures 7 to 13 of the accompanying
drawings.

page_text: 3. The construction combination and arrangement of parts constituting the
improvements in connection with fire-bars or grates of furnaces substantially as
hereinbefore described with reference to Figures 7 to 13 of the accompanying
drawings.
Dated the 26th day of January 189.1
JOHNSONS & WILLCOX,
Agents.