Improvements in Apparatus for Supplying Jets of Air, or Steam and Air Combined, to Furnaces.
Year: 1894

page_text: Date of Application, 12th June, 1894
Complete Specification Left, 11th Mar., 1895-Accepted, 13th Apr., 1895
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Supplying Jets of Air, or Steam
and Air Combined, to Furnaces.
I, WILLIAM BRACEWELL of Brinscall, near Chorley in the County of
Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows, that is to say :-
The object of my invention is the construction of apparatus, for improvements
upon Letters Patent granted to me on the 4th day of October 1892; and
numbered 176 9 for "Improvements in apparatas for supplying jets of steam and
air to the furnaces of steam boilers" and my improvement has for its object, a
more extended application of the said Letters Patent to all kinds of furnaces, such
as steam-boilers, puddling furnaces and refuse destructors. The same being
accomplished by mechanical and other means--whereby more direct currents of
air, or steam and air combined, can be brought to act on the underside of the
fire-grates.
To accomplish my object I place beneath the furnace perforated tubes; the same
being carried the full length of the fire-grate surface, from which jets of air, or
steam and air combined are made to impinge upon the lower side of the burning
fuel; my object being to further the admission of more oxygen from the atmosphere,
than can be obtained by a natural draught, and that a better combustion can be
obtained behind the back bridge of the furnace, I place a baffle bridge made from
fire-clay and asbestos blocks so as to impede the volatile gases emitted froni the
burning fuel, the said baffle bridge having circular and vertical openings through
the same for the interception of the flame, and thereby intermixing the gases with
a supply of heated air forced by a jet placed over the fire, the combustion created
by this intermixture being so great as to dispense with the emittance of black smoke
from the chimney.
To carry out my invention-I place beneath the fire-bars of the said furnaces one
or more perforated pipes for the conveyance of air or steam and air, to the under-
side of the furnace bars, the perforations being made in the pipe for the full length
of the furnace, so that when a current of air under pressure is forced along the
pipe the air or steam and air combined is brought into direct contact with the
whole of the burning fuel, the impetus with which the said air is delivered between
the bars and in contact with the fire being so great as to create a better combustion
by imparting more oxygen to the burning fuel.
The propelling agent to establish these jets or currents of air from the pipe are
generated by a jet or jets placed within an enlarged end of the perforated pipe-
so as to induce a current of atmospheric air to enter the pipe.
Various propelling fluids under pressure being used to induce the said currents,
according to the work required, as in some cases I prefer to use compressed air as
the propelling agent for actuating the jets, having imparted to it when' desired a
certain percentage of moisture for intermixture with the air induced within' the
perforated pipe, so as to cool and moisten the bars of the furnace and assist the
combustion of the fuel.
In other cases where a greater percentage of moisture is required-1 dispense
with the compressed air, and use steam as the propelling fluid to actuate the jets.
The perforated vives are for a short distance enlarged at the front end, being.

page_text: constructed to admit the jet for the propulsion of the current, so that when the
fires are cleaned and drawn over the dead plate of the furnace, no impediment is
caused to the action of the jets by the burning fuel being drawn upon them.
The entrance to the pipe being provided with a sliding damper, so that when
desired the jets may be enclosed within the pipe.
The termination of the pipe is closed similar to an egg-ended tube so that the
number and size of the perforations may be regulated to obtain a slight pressure
within the pipe.
To carry out the construction of the combustion chamber behind the fire, and to
work the same in connection with the amount of air forced over the fire, I erect a
baffle bridge in close proximity to the furnace, the same being made from fire-clay
blocks, having two or more circular openings on the lower part thereof, the upper
portion being arranged with narrow vertical slot holes, carried the full width of
the furnace flue, the inner surfaces of these slot holes being encased with asbestos,
so that the volatile gases may be more readily ignited when in contact with the
baffle bridge. The fire bars for the furnace are made hollow, having the lower
part of each end of the bar cut away, so that a current of air is made to pass
through the bar from the front to the back of the furnace, the air spaces being made
more in number at the front and back of the furnace than in the centre.
Dated this 12th day of June 1894.
WILLIAM BRACEWELL.
Improvements in Apparatus for Supplying Jets of Air, or Steam
and Air Combined, to Furnaces.
I, WILLIAM BRACEWELL of Brinscall near Chorley, in the County of
Lancaster, Engineer 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 and by the following statement :-
The object of this invention is to provide apparatus whereby jets of air or
jets of steam in conjunction with a prescribed volume of atmospheric air may be
supplied to furnaces the same being improvements upon Letters Patent granted
to me on the 4th day of October 1892 and numbered 17609 for "Improvements in
apparatus for supplying jets of steam and air to the furnaces of steam boilers," and
my invention has for its object a more extended application of the said Letters
Patent, to all kinds of furnaces, such as steam boiler or puddling furnaces, refuse
destructors, and other furnaces and fire-grates in the applied arts and manufactures,
the same being accomplished by mechanical and other means, whereby more direct
currents of heated air or steam and air combined are made to issue from nozzles
placed upon tubes, beneath the fire grate surface, each tube being made to terminate
with a nozzle within a combustion chamber beyond the fire, whereby an increased
volume of atmospheric air may be supplied to furnaces in order to promote the
complete combustion of the fuel and prevent the formation of dense or black
smoke.
It consists essentially of perforated egg ended tubes placed beneath the furnace
bars, having nozzles secured to their outer periphery, from which currents of air
or steam and air combined is admitted to the underside of the furnace bars;
a nozzle is placed at the termination of each tube to discharge a current of air
within a combustion chamber, and in combination therewith of hollow spaces in
the fire bar, by which the currents of air after being delivered from the nozzles are
heated to a high temperature, and a baffle bridge to deflect the products of com
bustion and heated gases and cause a complete intermingling of them, with the
air or steam and air combined as admitted to promote the complete combustion.

page_text: The invention will be fully described with reference to the annexed drawings in
which parts of a steam boiler, furnace and flue are shown sufficient to illustrate it.
Fig. 1. longitudinal sectional elevation through the furnace.
Fig. 2. transverse elevation of furnace.
Fig. 3. transverse elevation of a modified form of the appliance.
The boiler A, the furnace B, and the flue g', to which the invention is applied,
are of any ordinary form or construction.
The jet or injector e is placed within the enlarged end of egg ended tubes C
and C to distribute the mixed steam and air within the same.
The smaller nozzles a distribute the current along the under side of the fire, the
current being heated in its passage between and through the hollow spaces of
the fire bars D.
•
The nozzles at the termination of the tubes C and C' deliver any excess of
current within the combustion chamber E. The heated gases passing from the
furnace, become intermixed with a fresh supply of atmospheric air from the
nozzles, the outlets in the baffle O being regulated to suit the exit of the gases
in accordance with the draught of the chimney.
Within the combustion chamber E formed behind the furnace with the baffle O,
a secondary combustion is set up, the unconsumed particles of carbon and the heated
gases passing from the furnace, come into contact with the heated air issuing from
the nozzles, and an almost complete combustion ensues preventing the passing
away of black or dense smoke.
The force of the current from nozzles being so great. as to induce a quicker
passage of the gases over the bridge H and through the openings within the
incandesent baffle O, the speed of the current being so great as to induce a quicker
draught of air through the fire, by this means a better combustion of the fuel
ensues, and more steam is generated.
By modifying the arrangement, the steam jet e, within the enlarged end of the
tube C and C may be dispensed with, and the mechanical arrangement of an air
propellor or fan S substituted for propelling the current, the enlarged end of
tubes C and C being connected by a chamber L attached to the air propellor S
or if desired the application of Baker's or other pressure blower for forcing a.
current of air.
Steam jets t and t¹ of ordinary construction are inserted in chamber L being
placed concentric with the tubes C and C¹ for moistening the current of air, the
combination of air and steam being delivered from nozzles a and f.
Referring to Fig. 1, 2, 3 the tubes C and Care constructed as shown in Fig. 1,
having nozzles a attached to their outer peripheries, from which currents of air
pass at a high speed to the fire. The contracted ends of the tubes C and C¹
having nozzle connections to the combustion chamber E. The nozzles e shown
within the enlarged ends of the tubes Fig. 1, are connected by tubes h fitted with
suitable valve k, with the steam space of the boiler.
Referring to Fig. 2 and 3 the steam jets t and t¹ are placed concentric within the
enlarged ends of tubes C and C¹, being connected by steam tube h, fitted with
suitable valve with the steam space of the boiler.
The hinged door J is attached to the ordinary furnace door G, as a means of
admitting at will a small volume of air after each firing, and is only given by way
of illustration.
Referring to Fig. 3 the perforated tubes C and C¹ are connected together by
chanber L, provided with a conical mouthpiece p, in which the air propellor S is
placed concentric with the opening p, the force of the current imparted by the
propellor S, inducing additional currents of air within the conical mouthpiece and
conducted by chamber L to the tubes C and C' and thence by the nozzles a and f
to the fire and gases within the combustion chamber-the steam jets t and t¹ being
used when desired to impart moisture to the current, and if needed to induce the
current when the propellor S is not working.
Referring to Fig. 1 each fire-bar D is built up of two parts, having projections »

page_text: &n along the bar, so that when placed and riveted together the opening or hollow
part T is formed' through the bar, for the diffusion and heating of the current after
delivery from the nozzles a.
Referring to Fig. 1 the baffle or plate O is fixed in the flue g', to form the
combustion chamber E behind the furnace, the baffle having circular openings. X
of a small diameter in the upper part of the flue, and vertical spaces X' in the
lower part of the flue, the heated gases passing from the furnace being impeded in
their progress, cause the baffle to become highly heated-the products of combustion
from the furnace being obliged to pass through the contracted openings X and X',
thereby complete combustion ensues preventing the passing away of black or dense
smoke.
I prefer to increase the incandescence of the baffle by placing asbestos linings
within the spaces X and X'.
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. An apparatus for supplying jets of air or steam and air combined to furnaces,
constructed with tubes placed under the fire-bars, having nozzles placed on the
outer periphery of the tubes, as a means of conveying air to the burning fuel of
furnaces, as and for the purpose described.
2. Apparatus for supplying jets of steam and air to furnaces, consisting of
egg-ended tubes with an enlarged end having a jet placed within the same for
inducing and forcing a current within the tube-having nozzles placed along the
full length of the tube and a discharge nozzle from the end of the tube within
the combustion chamber behind the bridge, substantially as described.
3. The combination with the apparatus herein described for supplying jets of air
or steam and air combined to furnaces, of a hollow fire bar, made from two longi-
tudinal bars riveted together, having projections to form a cavity between them, for
beating the air after being delivered from the nozzles before passing to the
burning fuel.
4. The combination with the apparatus herein described of a fire clay sectional
baffle, provided with holes and vertical passages for the gases to pass through
placed in the flue to form a combustion chamber, through the openings in which
the current is propelled by the air and steam forced through the tubes substantially
as described.
5. The application of an air propellor or fan, placed in connection with the tubes
and nozzles beneath the fire substantially as described for the purpose of supplying
air to furnaces.
6. Apparatus for supplying air or steam and air combined to furnaces, substan-
tially as described.
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WILLIAM BRACEWELL.