PROVEMENTS IN MEANS APPLIED TO THE FIRE-BRIDGES OF FURNACES FOR EFFECTING THE COMBUSTION OF SMOKE AND FURNACE GASES.
Year: 1878

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LETTERS PATENT to Jonathan Ireland, of Edward Streot, Broughton Lane,
Manchester, in the County of Lancaster, and Thomas Holt, of Phoebe Street,
Regent Road, Salford, in the County of Lancaster, for the Invention of "IM
PROVEMENTS IN MEANS APPLIED TO THE FIRE-BRIDGES OF FURNACES FOR
EFFECTING THE COMBUSTION OF SMOKE AND FURNACE GASES.".
PROVISIONAL SPECIFICATION left by the said Jonathan Ireland and
Thomas Holt at the Office of the Commissioners of Patents on the 3rd
August 1878.
JONATHAN IRELAND, of Edward Street, Broughton Lane, Manchester, in the
County of Lancaster, and THOMAS HOLT, of Phoebe Street, Regent Road, Salford,
in the County of Lancaster. "IMPROVEMENTS IN MEANS APPLIED TO THE FIRE-
BRIDGES OF FURNACES FOR EFFECTING THE COMBUSTION OF SMOKE AND FURNACE
GASES."
According to the present Invention the fire-bridge of a furnace is made double or
with a hollow space extending from top to bottom. This space communicates at
bottom with the space below the furnace and has fitted into it at the top of the
bridge a metal framing serving to support loose bars running longitudinally of the
bridge and formed in a similar manner to ordinary fire-bars, with narrow openings.
between them. By this means the air passing up through the hollow space is made
to issue in a number of thin jets through the same narrow openings, which jets of
heated air in impinging upon the smoke and gases passing over the bridge effect
their complete combustion.
By the above-described arrangement the advantage gained that the number
and thickness of the bars can be at any time altered, according as more or less air is
required, also the bottom of each bar being brought to a feather edge, any dirt or
ash can readily fall through into the ash-pit below.
:
.
In cases where there is not sufficient room to allow of a double fire-bridge of
brickwork, the one wall thereof may be replaced by an iron plate.

page_text: applied thereto.
Fig. 2 is a side view of one of the bars of the air grating; and Figs. 3, 4, and 5,
are plans shewing various forms of the said bars suitable for giving varied amounts
of air passage in the spaces between them.
A is the fire-bridge which may be built of brick or fire-lumps in the usual manner,
but instead of resting on the bottom of the boiler flue it is placed on a plate B
extending across the flue at some height from the bottom, and leaving under it a
passage for air.
Behind the bridge is fixed a plate C, and the top of this plate is connected to the
top of the bridge by an inclined frame D in which are laid a number of thin bars E
extending lengthwise of the bridge. These bars are feather edged or thinned at their
lower edges so that ash or dust that may enter the spaces between them can readily
clear itself and fall into the air chamber behind the bridge, whence it can from time
to time be raked.
The bars have fillets F' on them, either on both sides, as shewn in Fig. 3, or only
on one side, as shewn in Fig. 4, or the fillets may be altogether absent, as shewn
in Fig. 5; and various numbers of these bars filleted, or partly filleted and
partly unfilleted, may be employed to make up the grating, according to the
amount of air passage required to be provided through the interstices between
.the bars.
As indicated by the arrows, air enters the chamber behind the bridge, and being
warmed therein rises through the intervals between the bars at E in subdivided
streams or layers which mingle with the smoke and gases that have passed over the
bridge so as to effect or promote their complete combustion.
Having thus described the nature of the said Invention, I hereby declare that I
make no general claim to admitting air to mingle with the products of combustion of
a furnace behind the bridge, but I claim admitting air behind the bridge of a furnace

page_text: in subdivided streams or layers through the intervals between loose removeable bars
extending lengthwise of the bridge, and laid in an inclined frame, substantially as
and for the purpose herein set forth.
In witness whereof, I, the said Jonathan Ireland, have hereunto set my hand
and seal, this Twenty-second day of January, in the year of our Lord One
thousand eight hundred and seventy-nine.
JONATHAN IRELAND. (L.S.)