Improvements relating to Steam Boiler and other Furnaces.
Year: 1895

page_text: Date of Application, 1st Mar., 1895
Complete Specification Left, 30th Nov., 1895-Accepted, 18th Jan., 1896
PROVISIONAL SPECIFICATION.
Improvements relating to Steam Boiler and other Furnaces.
I, EDMUND HOWL, of The Quarries, near Dudley, in the County of Stafford,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in steam boiler and other furnaces, such
improvements being specially applicable to the furnaces, described in my
Specification No. 24434, of 1893, on which a Patent has been granted to me, and
to other types in which a forced or induced draught is employel.
The objects of my present invention are to obtain a more efficient distribution of
the forced or induced draught or current of air, and by heating the same before
admission to obtain a more complete combustion of the fuel in the furnace. Further,
to arrange a more convenient and efficient form of the fuel supporting surface, and
to construct the steam nozzle for inducing a strong draught, or current of air with
but a minimum consumption of steam, the secondary or rear bridge door or
damper when such is employed having its fittings so arranged as to offer no
obstruction to the introduction of tools for clearing out the dust carried over the
bridge by the action of the blast.
In the application of my invention I arrange trunks or conduits, preferably two
in number, beneath the fire grate through which the forced or induced draught is
conveyed to a heater or retort which I fix beyond the fire bridge. The air heater
or retort is preferably arranged with two side passages or chambers for the intro-
duction of the air aud one central passage through which the air is returned to
other trunks or conduits arranged beneath the fire grate. The roof or upper part
of the air heater or retort has inclined sides in order to prevent the lodgment of
dust blown over the bridge.
The heated air is conveyed from the retort to the front of the furnace by means
of the trunks or conduits hereinbefore described, and is then admitted to a hollow
dead plate or like chamber through which it passes over the fire grate. Instead
of returning the heated air to the front end before introduction to the fuel, I
sometimes form suitable apertures in the grate surface and thus admit the air direct
from the return trunks or conduits to the fuel. I preferably graduate the size and
number of the apertures within a given area along the return conduits in order to
obtain a more even distribution of the blast, and I sometimes adopt the same
method of distribution in furnaces having direct blast from the front of tho
boiler.
I construct a grate for the furnace froin one or more plates of an arched,
corrugated, or wave like form having conical or other holes or apertures for the
passage of the blast. These plates are supported on open top blast conveying
trunks or conduits, the blast being induced either at the mouth of such conduits by
a steam jet or other appliauce, or at the mouth of the cold air admission truuks
formed beneath the grate as hereinbefore described. The air thus courses along
the trunks through the retort, returning to boiler front by the closed conduit for
forcing or inducing the air thus heated through the fire. The conduits are supported
from the lower part of the furnace in the manner described in my Specification
No. 24434, of 1893.
Instead of a grated plate surface I sometimes employ a combination of perforated
arched or corrugated or wave-like plates supported upon the air trunks or conduits

page_text: with fire hars or grated plates interposed between the forced draught conduits, and
arranged to permit the passage through to the fire of the natural chimney draught.
The jets or currents of forced draught passing into the fire from the perforations
immediately adjacent to the interposed bars or grated plates, assist the chimney
draught in the drawing of additional air through the fuel and thus a more efficient
combustion is effected.
I sometimes convey a secondary supply of air to the fire bridge by means of a
passage or conduits beneath the fire grate and between the primary air trunks, and
1 preferably cause the issuing air to be deflected, upwards immediately at the back
of the bridge by means of a fixed and inclined plate baving an opening at its lower
end through which the flue dust or like deposit passes to the bottom of the furnace
tube. In like manner I sometimes employ a retorted air supply to the bridge. To
prevent the tue dust or like solid matter from being carried a great distance
beyond the bridge, 1 build a second bridge beyond the first fire bridge for the
purpose of retaining the deposit in the space between the bridges whence it may be
readily removed through the cleauing thoroughfare beneath the grate.
I employ my heater or retort for the purpose of heating the air to be employed
in the ordinary closed ash-pit, and to obtain a more efficient distribution of the
blast, I turn the mouth of the blast pipe towards the boiler front or so form and
arrange it as to deflect the issuing current of air and prevent excessive pressure at
the rear end of the ashpit. I employ this special forin.of blast pipe either with or
without the heater herein before described.
I construct my improved nozzle for inducing a strong blast of air with an outer
casing or shell preferably of a circular conical configuration, and a similarly shaped
hollow adjustable plug is screwed or fitted into the conical shell. Steam is admitted
to the space between the outer shell and the interior adjustable plug and issues
from the inner end of the same as a thin annular film. The mountings of the
nozzles are preferably composed of rings of metal with a bowed cross-bar, the
external air being induced through the centre of the plug aud also through apertures
surrounding the nozzle shell, by the action of the issuing nunular jet of steam.
A supply of super-heated steam is preferably conducted to the nozzles by means of
pipes arranged within the bonnet or casing of the furnace front. I construct and
arrange my improved door and fittings for attachment on the lower side of the
secondary or rear fire bridge or at the front bridge, in such a manuer that the
lower side or bottom of the furnace flue is left level on the opening of the door,
the bottom side or edge of the door or damper seating directly against the concave
bottom of the tube. The bottom of the furnace is thus left quite clear permitting
the ready and convenient working of the clearing rods or tools.
Dated this 28th day of Kebruar 1906
MARKS & CLERK,
18 Southampton Buildings, London, W.C., and
13 Temple Street, Birmingham, Agents for the Applicant.
Improvements relating to Steam Boiler and other Furnaces.
1, EDMUND HOWL, of The Quarries, near Dudley, in the County of Stafford, 4
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 :-
This invention relates to improvements in steam boiler and other furnaces, such
improvements being specially applicable to the furnaces described in my Specification 5
No. 24434 of 1893, on which a Patent has been granted to me, and to other types
in which a forced or induced draught is employed.

page_text: The objects of my present invention are to obtain a more efficient distribution of
the force or induced draught or current of air, and by heating the same before
admission to obtain a more complete combustion of the fuel in the furnace.
In order that iny invention may be the more readily understood, I append
horeunto two sheets of explanatory drawings to be hereinafter referred to.-
On Sheet 1, Figure 1 is a sectional elevation representing the application of my
invention to a boiler furnace fitted with fire bars.
Figure 2 is a part sectional plan of the rear or fire bridge end of the air
conduits.
Figures 3 to 6 inclusive are end views of the boiler furnaces and sections
through the same.
On Sheet 2, Figure 7 is a sectional elevation representing my improvements as
applied to a boiler furnace fitted with a solid or plated grate.
Figure 8 is a part sectional elevation of the rear or fire bridge ond of the air
conduits carrying retort ends.
Figures 9 to 12 inclusive are end views of the boiler furnaces, and sections
through the same.
The same reference letters in the different views indicate the same parts.
In the application of my invention 1 arrange trunks or conduits, preferably two
in number, and each as A on Sheet 1, beneath the fire grate B, through which
conduits the forced or induced draught is conveyed to the rear or fire bridge ond
of the furnace. At the fire bridge end the currents of air coming through the
conduits A are reversed, by means of the bend connections C, and directed towards
the front end of the boiler. In travelling through the conduits the air becomes
heated before its admission to the furnace, and by deflecting the currents towards
the front end of the furnace I obtain a more efficient distribution of air through
the fire grate.
It is to be understood that the air after travelling along the conduit and turning
at the end of the said conduit, is discharged under the fire bars or grate, and finds
its way through the said fire bars or grate.
I sometimes construct a solid or plated grate for the furnace from plates auch
as D illustrated on Sheet 2, of an arched, corrugated, or wave like form, having
conical or other holes or apertures for the passage of the blast. These plates are
supported on open top blast conveying truuks or conduits, the blast being induced
either at the mouth of such conduits by a steam jet or other appliance, or at tho
montha E of the cold air admission trunks E formed beneath the grate as illustrated
in the figures. The air thus courses along the trunks E around the bend at the
bridge end, returning to boiler front by the conduits F, and is thus heated before
passing through suitable apertures into the furnace.
The conduits are supported from the lower part of the furnace by means of the
adjustable screw feet G in the manner described in my Specification No. 24434
of 1893, hereinbefore referred to.
I sometimes convey a secondary supply of air to the fire bridge by means of a
passage such as H, or suitable conduits beneath the fire grate and between the
primary air trunks, and I preferably cause the issuing air to be deflected upwards
immediately at the back of the bridge by means of a fixed plate or an inclined end
such as beyond the fire bridge having an opening at its lower end through
which the flue dust or like deposit passes to the bottom of the furnace tube. In
like manner I sometimes employ a retorted or heated air supply to the bridge. To
prevent the flue dust or like solid matter from being carried a great distance
beyond the bridge, I sometimes build a second bridge beyond the first fire bridge
for the purpose of retaining the deposit in the space between the bridges whence it
may be readily removed through the cleaning space or thoroughfare such as J,
which I provide beneath the grate.
I sometimes employ a heater or retort such as K Figures 8 and 12, which I fix
beyond the fire bridge L, for the purpose of further heating the air before reversing
or deflecting it towards the boiler front.

page_text: ригрозе
I preferably employ a steam nozzle and fittings M at the mouth of the air
conduits for obtaining the required forced blast, the steam employed for the
being first superheated by passing through a pipe heater N projecting within the
-furnace.
I do not limit the application of my invention to any one class or type of
boiler, but adapt the same to boilers and furnaces of varying construction,
making such modifications as may be necessary to suit the requirements of particular
* services.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manuor the same is to be performed, I declare that what I
⚫claim is.―
1. In steam boilers and other furnaces the method of obtaining an efficient
distribution of the forced or induced draught or current of air, and of heating the
same before its admission to the fire grate, by means of trunks or conduits so
-arranged as to deflect the air towards the boiler front after its couvoyance to the
bridge, substantially as described.
2. In steam boiler and other furnaces the use of deflecting connections in
-combination with air trunks or conduits arranged beneath the grate substantially
as and for the purposes bereiubefore described and as illustrated in the accompanying
-drawings.
3. In steam boiler and other furnaces the combination of a bar grate with air
conduits and a cleaning space or thoroughfare beneath the same substantially as
hereinbefore described and as illustrated in the accompanying drawings.
4. In steam boiler and other furnaces the combination of a solid or plated
grate with air conduits and a cleaning space or thoroughfare beneath the same,
and with or without a passage or conduit for a secondary air supply,
substantially as hereinbefore described, and as illustrated in the accompanying
drawings.
5. Iu steam boiler and other furnaces the use of a heater or retort beyond the
bridge substantially as and for the purposes described.
6. The improved general construction and arrangement of a steam boiler or other
furnace substantially as and for the purposes described.
Dated this 30th day of November 1895.
MARKS & CLERK,
18 Southampton Buildings, London, W.C., and
13 Temple Street, Birmingham, Agents for the Applicant.