Improved Firebridge for Furnaces.
Year: 1899

page_text: Date of Application, 2nd Dec., 1899
Complete Specification Left, 2nd Oct., 1900-Accepted, 3rd Nov., '1900
PROVISIONAL SPECIFICATION.
Improved Firebridge for Furnaces.
We, SAMUEL HALLET BAKER, and WILLIAM HALLET BAKER, Ironmongers, both
of Bracknell, in the County of Berkshire, do hereby declare the nature of this
invention to be as follows:
A furnace bridge according to this invention is primarily for consuming smoke
which has the result of economising fuel, and is constructed as follows: The
bridge is preferably made of a cast iron hollow foundation faced where the fire
will meet it, with a fire resisting material, or it can be moulded entirely in the
material having stays of iron embedded in it to strengthen it. The front of the
bridge is made higher than usual and hangs towards the fire, on this front part
is the cross bearer for that end of the bars, which bearer may be placed slightly
below the horizontal. An opening is made in upper part of bridge for exit of air
which comes in through an opening in the foundation of the bridge below the
bars. By this plan the air is highly heated before its escape into the flue.
Baffle plates may be inserted in the air passage and a damper provided to control
the quantity of air admitted.
Dated this 2nd day of December 1899.
FREDERIC PRINCE,
Agent for Applicant.
We, SAMUEL HALLET BAKER and WILLIAM HALLET BAKER, Ironmongers, both
of Bracknell, in the County of Berkshire, 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 any by the following statement:-
This invention refers to certain improvements in firebridges for furnaces as
hereafter described, the object being to supply fresh heated air to the products
of combustion in order to render the furnace smoke consuming, and to increase
its efficiency by the regenerative effects of the air so introduced.
With this object in view the furnace firebridge (which is made hollow) is
constructed to somewhat overhang the furnace, fresh air being admitted to the
interior of the bridge from below the firebars, the air so admitted passes into
and through the overhanging part of the bridge, and becoming thereby highly
Di Q71

page_text: heated, is delivered in this condition by valve or shutter controlled apertures in
the upper part of the bridge where it meets and commingles with the products
of combustion. The delivery apertures may be located both at the front and back
of the upper part of the bridge and also at the top of the firebridge and the
shutters for controlling these apertures, we so connect by levers, links and the
like that they may be conveniently be operated from the front of the furnace.
In order that our invention may be readily understood we will describe same
with reference to an example of construction shewn in the accompanying draw-
ing, where Fig. 1 is a longitudinal vertical section of so much of a steam boiler
of locomotive type as is necessary to shew our invention applied thereto, and
Fig. 2 is a front sectional elevation shewing the firebridge so fitted.
The firebridge may be conveniently composed of a cast or wrought iron cas-
ing A which is encased at those parts which it is likely to be subjected to the
furnace heat with refractory material B, or the firebridge may be entirely made
or built up of refractory material suitably strengthened by iron stays.
At
The firebars C are supported upon a bearer C, below which there is an aper-
ture D in the firebridge by which air is admitted into the interior thereof.
a short distance above the firebars, the bridge begins to somewhat overhang the
furnace and terminates in a vertical head E in the face of which there is an air
exit aperture F. An air exit aperture G is also formed in the rear wall of the
firebridge, and in the top of the bridge there is an exit H.
These apertures extend nearly the whole width of the bridge, as is shewn at
Fig. 2, and the exits F and G are fitted, in the interior of the bridge, with
hinged shutters F and G¹ to control the exit of heated air.
The shutter being in the interior of the bridge, are fitted with connections by
which they may be operated from the front of the furnace, thus the shutter G¹
is hinged to the rear wall of the bridge, and is provided with an arm G³, to
which is pivotted one end of a connecting rod J, the opposite end of which is
jointed to one arm of a lever J1, the other arm of which is connected to a chain J2,
the latter chain being guided over pulleys such as J³, and passing to the frout
of the furnace. The shutter G¹ is so balanced that it tends to fall open, but can
be closed or partly closed by pulling the chain J¹.
The shutter FI is balanced by a weight K so as to normally remain closed,
and is opened as required by means of a rod L (indicated by dotted lines) con-
nected to a lever such as J and operated as described with reference to the latter
lever.
Obviously the mere connections by which the shutters are controlled may be
varied to suit any particular requirements, and when desired the interior of
the bridge may be fitted with baffle plates to retard the velocity of the air current
within the bridge.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim is:
1. In a firebridge for furnaces wherein the bridge is of hollow formation,
making the said bridge to somewhat overhang the furnace, forming an aperture
in the front of the bridge below the firebars to admit air to within the bridge.
an exit aperture in the upper part of the bridge by which the heated air is de-
livered to the combustion gases, and a shutter for wholly or partly closing the
exit aperture, and means for operating such shutter from the front or other con-
venient part of the furnace substantially as set forth.
2. In a firebridge for furnaces wherein the firebridge is of hollow construction,
forming the said bridge to overhang the furnace, there being an aperture beneath
the firebars to admit air within the bridge, and exit apertures in the upper part
of the bridge to deliver the heated air one such aperture being in front, one at
the rear, and one at the top of the bridge and means for controlling the said
apertures substantially as set forth.

page_text: 3. In a firebridge for furnaces wherein the bridge is of hollow structure, the
particular construction and arrangement of parts substantially as and for the
purpose described with reference to the accompanying drawings.
Dated this 1st day of October 1900
FREDERIC PRINCE,
Agent for Applicant.