IMPROVEMENTS IN THE CONSTRUCTION OF APPARATUS TO BE APPLIED TO FURNACES FOR THE PREVENTION OF SMOKE
Year: 1882

page_text: LETTERS PATENT to William Begg, of Sale, in the County of Chester, for
an invention of "IMPROVEMENTS IN THE CONSTRUCTION OF APPARATUS TO
BE APPLIED TO FURNACES FOR THE PREVENTION OF SMOKE"
PROVISIONAL SPECIFICATION left by the said William Begg at the Office
of the Commissioners of Patents on the 26th April 1882.
"IMPROVEMENTS IN THE
WILLIAM BEGG of Sale in the County of Chester
CONSTRUCTION OF APPARATUS TO BE APPLIED TO FURNACES FOR THE PREVENTION
OF SMOKE
"
"
This invention relates particularly to that part of a furnace called the "bridge'
the object of the said invention being so to construct the said bridge as to admit
to the furnace at that point a very large number of finely divided jets of heated
air, which mingling with the heated gases and other products of combustion will
cause the same to be entirely consumed and thus prevent the formation of smoke.
I make the bridge of fire clay in two parts divided horizontally, the upper part
being (by preference) further divided perpendicularly through the centre to
facilitate its introduction into the furnace.
The whole of the upper part is perforated vertically with a very large number
of small openings such perforations being made to taper upwards so that any dust
or small particles of fuel entering at the top will fall clear through without choking
the perforations.
This upper part of the bridge is supported by a shoe of cast iron which also
embraces the lower part of the bridge and thus the whole is firmly held together.
The front of the upper part is bevilled off at the top to an angle of about 45°
so as to allow the air from the ash pit to have free access to the lower ends of the
perforations of the upper part of the bridge.
This bevilled portion also directs any dust
nerforations into the ash pit.
which may fall through the

page_text: It will be evident that, when the furnace is at work, the air from the ash pit
will be drawn into the furnace through the numerous perforations in the bridge,
and thus a large number of finely divided jets of air will be admitted, the said air
being heated up to flame point by its passage through the conical porforations in
the firebrick bridge.
A door or damper is provided by which the amount of air admitted from the
ash pit can be regulated until the desired effect of a perfect combustion without
smoke is ascertained, after which no further adjustment will be required.
'
WILLIAM BEGO of Sale in the County of Chester IMPROVEMENTS-IN-THE-
CONSTRUCTION OF APPARATUS TO BE APPLIED TO FURNACES FOR THE PREVENTION
OF SMOKE"
"
This invention relates particularly to that part of a furnace called the "bridge
the object of the said Invention being so to construct the said bridge as to adinit
to the furnace at that point a very large number of finely divided jets of heated
air which mingling with the licated gases and other products of combustion will
cause the same to be entirely consumed and thus prevent the formation of smoke.
Such being the nature and object of my said invention I will now proceed to
describe in detail the manner in which the same is to be or may be performed or
carried into practical effect, and in order that the same may be clearly understood
I have annexed hereunto a sheet of drawings illustrative thereof and have marked
the same with figures and letters of reference corresponding with those in the
following explanation thereof.
In the annexed drawing Fig. 1 is a transverse section through the furnace end
of the flue of a steam boiler in front of the bridge and with the fire bars removed.
Fig. 2 is a longitudinal section through the bridge with the air door or damper
shown as closed and Fig 3. is a similar section showing the air door or daimper
open.
I make the bridge of fire clay in two parts a, a and b, b divided horizontally,
the upper part a, a being (by preference) further divided perpendicularly through
the centre as at c, c Fig. 1. to facilitate its introduction into the furnace.
The whole of the upper part a, a is perforated vertically with a very large
number of small openings d, d (see also half plan view Fig. 4) such perforations
being made to taper upwards so that any dust or small particles of fuel entering
at the top will fall clear through without choking the perforations d, d. This
upper part a, a of the bridge is supported by a shoe c, e' of cast iron which also
embraces the lower part b, b of the bridge and thus the whole is firmly held
together. The front of the lower part b, bis bevilled off at the top to an angle of

page_text: about 45° (mor or less) so as to allow the air from the ash pit f,f to have free
access to the lower ends of the perforations d, d of the upper part a, a of the
bridge.
This bevilled portion also directs any dust which may fall through the
perforations into the ash pit f, f
It will be evident that when the furnace is at work, the air from the ash pit f.f
will be drawn into the furnace through the numerous perforations d, d in the
bridge, and thus a large number of finely divided jets of air will be admitted, the
said air being heated up to flame point by its passage through the conical per-
forations d, d in the upper part a, a of the fire brick bridge. A door or damper 9,9
is provided by which the amount of air admitted from the ashpit can be regulated
until the desired effect of perfect combustion without smoke is ascertained after
which no further adjustment will be required as it then works automatically.
A back view of this door or damper is shown detached at Fig. 5. Fig. 6 being a
transverse section of the same at the line A. B in Fig. 5. This door or damper g, g
is made with two pockets h and i ono at the front above the centre and one at the
back below the same, and there is a hole of communication between the two
pockets which can be more or less closed by means of a set screw *.
The back pocket i boing charged with a suflicient quantity of mercury to keep
the door g, g in the closed or vertical position shown at Fig. 2 when air is not
required to be admitted at the bridge.
Passing through a socket k, k attached to or formed with the shoe e, e and also
through a slot 1, in the door g, g there is a sliding bar m, m provided with a
finger n, n and jointed to a rodo, o the other end of which is connected to the
furnace door. When the furnace door is opened to "fire up" the rod o, o pulls the
sliding bar m, m in the direction of the arrow, causing the finger to act against
the upper part of the air door g, g and draw it over into the horizontal or open
position (shown in Fig. 3) so as to admit the full quantity of air through the
perforated bridge which at this time is in an incandescent state, by passing through
the perforations the air is heated up to flaine point and on mingling with the
smoke and gases from the freshly added fuel, effects a perfect combustion without
lowering the temperature of the furnace. When the opening of the furnace door
pulls the air door or damper g, g into the position shown in Fig. 3 the mercury
runs at once over the top of the partition into the front pocket h thus assisting
in keeping the air door g, g open, but when the furnace door is closed again after
firing it pushes the sliding bar m m in the reverse direction and the finger l,
coming against a tappet p on the back of the door g, g tilts the latter into the
position shown in Fig. 7. The mercury now commences to run from the front
pocket through the hole of communication into the back pocket i and as soon as
a sufficient quantity to overbalance the air door g, g has passed through into the
latter it falls back into its normal position (shown at Fig. 2) and shuts off the
admission of the air to the perforated bridge.
The time allowed to lapse between the closing of the furnace door by the stoker
and the automatic closing of the air door is regulated by the set screw
⚫ which
opens or closes the hole of communication between the two pockets h and i more
or less, and when this has once been regulated to suit the relative conditions of
the fuel, amount of draught, and other circunstances a perfect combustion ensues
and the action is quite automatic.
A great advantage of this apparatus is that owing to the automatic action of
the air door only a very small portion of air passes through the bridge excepting
when "firing up" and thus the bridge is brought up to a very high temperature
before the furnace doors are opened again and thus the air admitted at stoking time
is brought up to flaming point at once.
There are tubular air holes q, q, through the air door g, g to keep the mercury
cool, and a certain amount of air is always passing through these, but this amount
only assists combustion and does not lower the temperature in any appreciable
degree.

page_text: Having now described the nature and object of my said Invention together
with the manner in which the same is to be or may be performed or carried into
practical effect I would remark in conclusion that I am aware that perforated
bridges of various constructions have been previously employed for similar purposes,
and that dampers (more or less automatic in action) have been proposed to be used
for closing the ash pit door; and therefore I lay no claim to the general principle
of admitting heated air to a furnace through a perforated bridge nor to the use of
an ordinary self-acting damper in the ash-pit; but what I consider to be new and
desire to claim as my invention is the peculiar construction and application of the
perforated bridge as hereinbefore described and illustrated by the annexed drawings,
and the combination therewith of a self-acting damper in the ashpit constructed
and operating so as to give the amount of air required and at the proper
temperature in the manner hereinafter described.
In witness whereof I the said William Begg have hereunto set my hand
and seal this twenty first day of October in the year of our Lord one
thousand eight hundred and eighty two
WILLIAM BEGG (L.S.)