Improvements in and relating to Furnace Grates
Year: 1898

page_text: Date of Application, 17th Dec., 1898-Accepted, 25th Mar., 1899
COMPLETE SPECIFICATION.
Improvements in and relating to Furnace Grates,
1, CHARLES DENTON ABEL, of Birkbeck Bank Chambers, Southampton Build-
ings, in the County of London, Consulting Engineer and Chartered Patent Agent,
do hereby declare the nature of this invention (as communicated to me from
abroad by the Firm of Pollitzer and Co., of I, Hohenstanfengasse, No. 4, Vienna,
Merchants) 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 a new construction of furnace grate which may
be used either as a flat or stepped grate, with or without arrangements for
feeding forward the fuel, and either with natural draught or with forced
draught, or with cooling by the application of water.
The essential feature of the said fire grate consists in the employment for
the support of the fire bars of a frame composed of perforated tubes placed
parallel to each other and connected to either an air, steam or a water supply;
the furnace bars are provided with sharp-edged ribs or studs that are situated
upon and divide the openings of the tubes.
These ribs or studs protect the openings of the tubes against becoming choked
by the ashes &c., and divide the issuing jets of forced air or of air and steam
so that they do not tend to produce blowpipe-flames.
I will describe the said new construction with reference to the accompany-
ing drawings in which Fig. 1 shews a cross section and Fig. 2 a part plan of
one arrangement of the grate; Fig. 3 shews the part sectional end view thereof
and Fig. 4 shews a part longitudinal section.
Fig. 5 shews a part longitudinal section of the grate in stepped form, and
Fig. 6a view of part of a grate bar thereof detached. Figs. 7 and 8 shew a
section and plan of an arrangement in which the furnace bars run parallel with
the tubes.
The furnace bars A are formed with lateral ribs or studs a which taper
downwards to a sharp edge b. These bars are fitted together upon a support-
ing frame formed of parallel drawn-metal tubes Bin such manner that the
sharp edges are situated immediately over the small orifices c of the tubes B.
The studs a consequently prevent the ashes from falling into the openings of
the tubes. The total width of the bars A is somewhat smaller than the dis-
tance between two contiguous openings c. The contiguous furnace bars do con-
sequently not touch each other, and can therefore readily be brought with their
studs over the openings c. On the other hand, any warping of the furnace
bars when heated and consequently expanded in every direction, is prevented.
The bars A are formed with stiffening ribs d which project down between the
tubes B. The furnace grate can also be constructed with furnace bars run-
ning parallel to the tubes B, as shewn at Figs. 7 and 8 where each bar A con-
sists of the combination of a set of bars d d d connected together at the ends
and intermediate points by the parts shaped to fit over two adjacent tubes B,
the intermediate ribs a being arranged with their sharp lower edges over the
orifices, in the same way as the ribs or studs a of the first arrangement.

page_text: The tubes are fixed at their front ends to a box R' and at their back ends
to a box R2. With furnaces having a forced draught, air or a mixture of air
and steam is forced into the box R by means of a fan or an injector J Fig. 3.
The air then issues through the openings C, and being split up and deflected
by the sharp edges b, it is projected into the fuel on the grate, at the same
time drawing with it the air drawn into the ash pit by the chimney draught.
A saving of working power is consequently effected as compared with ordi-
nary furnaces with forced draught. Owing to the air or steam jets issuing
through the openings being split up and deflected as described, they cannot
give rise to blow pipe flames.
If the fuel employed is ordinary coal the forced draught from below may
be dispensed with, because there will always be a sufficient air space through
the grate.
An effectual cooling of the furnace bars, such as is necessary in particular
when caking coal is used, can be effected by supplying the tubes B with water,
either to such an extent that the tubes are always full, or so that it will flow
out to a greater or less extent through the openings C, which arrangement
should be adopted in the case of stepped grates.
When a grate bar becomes hot, the parts of the several tubes in contiguity
thereto generate steam which, in issuing through the holes, cools the bar and
passes into the fuel.
For facilitating the clearing of the tubes B, the boxes R¹ R2 are provided with
doors t¹², on opening which a clearing tool can be introduced.
Any solid matter collecting in the box R2 is discharged into the ash-pit on
opening the door t².
In the construction of stepped grate shown at Figs. and 6, the tubes B are
arranged in inclined positions, and the furnace bars A as also their studs a
are so formed with inclined upper surfaces that when fitted together they
form a stepped surface for the fuel to rest upon, as shewn.
The cross section of the tubes need not be circular as shewn; they can be
triangular or of any other suitable form.
Having now particularly described and ascertained the nature of this in-
vention and in what manner the same is to be performed I declare that what
I claim is:-
1. In a furnace grate, the combination of tubes such as B having openings c
which serve for the introduction of forced air, steam, or water, and furnace
bars A having ribs or studs a tapering to a sharp under edge b, which bars
are laid upon the tubes B in such manner that the edges bare situated upon
the openings e so as to prevent these from becoming clogged with ashes, and
to divide and deflect the issuing jet of air or steam or of both air and steam,
so that the same cannot produce blow pipe flames, substantially as described.
2. In a furnace grate constructed as set forth in the First Claim, the com-
bination with the tubes B of boxes or chambers R R2 which, are provided with
doors that enable the tubes to be cleared of deposit, substantially as
described.