IMPROVEMENTS: IN FURNACES
Year: 1875

page_text: LETTERS PATENT to Robert Dunn, of Wylam-on-Tyne, in the County
of Northumberland, Engineer, for the Invention of "IMPROVEMENTS:
IN FURNACES."
Sealed the 80th July 1875, and dated the 26th May 1875.
PROVISIONAL SPECIFICATION left by the said Robert Dunn at the
Office of the Commissioners of Patents, with his Petition, on the
26th May 1875.
I, ROBERT DUNN, of Wylam-on-Tyne, in the County of Northumber-
land, Engineer, do hereby declare the nature of my said Invention for
"IMPROVEMENTS IN FURNACES," to be as follows:-
.:
My Invention relates more particularly to that description of furnaces
for which Letters. Patent were granted to me, dated July 16th 1862,
No. 2042, and consists of certain improvements in the construction and.
arrangement of the fire-bars and the parts connected therewith,, whereby.
smoke is more. effectually prevented and greater economy in the
consumption of fuel is obtained..

page_text: My Invention is chiefly adapted for the furnaces of locomotive
engines, but it is also applicable to other descriptions of furnaces.
In carrying out my Invention the fire-bars, which are mado hollow,
having two channels, are constructed in one length, having the ends
curved, recessed, or otherwise formed so as to admit the air to pass &
through the bars at the rate that the engine is running.
The bearing bars are made with a projection or door at the bottom
side so as to catch the air which passes through the fire-bars at the
rate that the engine is running, and thereby prevent the clinker from
adhering to the firo-bars, and the fire-bars from burning away with the 1
molten slag:
The ash pan is provided with two doors, one at each end pivotted or
swivelling so as to regulate the air in such a manner that it may strike
the fire-bars at any required part; by this arrangement the air passes
into the ash pan at the rate at which the engine is running, and therefore 1
acts as a blast at the bottom of the fire.
In front of the ash pan there is provided a projection or mouth-picce,
which is fitted so as to catch the air and act as a jet to the fire, by which
means a sufficient blast is obtained to assist in the generation of steam
without the necessity for contracting the blast pipe. The blast pipe of a
the engine may therefore be sufficiently enlarged to prevent the firo
from passing through the tube and into the smoke box and out of the
chimney, whereby an economy of fuel is effected.
The air pipe inside the fire-box is protected by a water jacket tube
which is fixed to the fire-box with plugs opposite the holes so as to a
clean out any deposit that may be formed; an elbow pipe is also
attached to the water jacket tube so as to direct the air on to 'the
centre of the fire and mingle with the gases, whereby combustion is
promoted and the fire is prevented from lifting with the action of the
blast pipc.
g
When the air pipo is used without the water jacket it may be fixed to
the side of the fire-box with a tube through the fire-box, for the purpose
of admitting air from the fire-bars to such air pipe through a conducting
chamber or channel arranged at the exterior of the fire-box. I also
apply water tubes to the fire-box, which tubes I arrange, by preference, a
in an angular direction extending from the top to the sides, so as whilst

page_text: providing additional heating surface to serve as supports, whereby the
ordinary stays may be wholly or partially dispensed with. The tubes
may, however, if desired, be arranged transversely and made of a curved
shape or otherwise so as to serve simultaneously as stays and water
tubes. I also provide a plate at a short distance above the fire-box for
the purpose of preventing the water from rising by the ebullition of
the water from the tubes so as to expose the surface of the fire-box to
the action of the fire, and cause the boiler to prime rapidly. These
improvements may be applied either separately or in combination as
desired.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Dunn in the Great Seal Patent Office on
the 25th November 1875.
"
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
DUNN, of Wylam-on-Tyne, in the County of Northumberland, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of May, in the
year of our Lord One thousand eight hundred and seventy-five, in
the 38th year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Robert Dunn, Her
special license that I, the said Robert Dunn, my executors, admi-
nistrators, and assigns, or such others as I, the said Robert Dunn,
my executors, administrators, or assigns, should at any time agree
with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN FURNACES," upon the condition (amongst others) that
I, the said Robert Dunn, my executors or administrators, by an instru-
ment in writing under my hand and seal, should particularly describe
and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and imme-
diately after the dato of the said Letters Patent.

page_text: NOW KNOW YE, that I, the said Robert Dunn, do hereby declare
the nature of my said Invention, and in what manner the same is to
bo performed, to be particularly described and ascertained in and by
the following statement, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to
say:
My said Invention relates more particularly to that description of
furnaces in respect of which Letters Patent were granted to me, bearing
date the Sixteenth July, One thousand eight and sixty-two, No. 2042,
and consists of certain improvements in the construction and arrange-
ment of the fire-bars and the parts connected therewith, whereby smoke
is more effectually prevented and greater economy in the consumption
of fuel and other advantages are obtained.
My Invention is chiefly adapted for the furnaces of locomotive
engines, but it is also applicable to other descriptions of furnaces.
And in order that my said Invention may be fully understood, I shall
now proceed more particularly to describe the same, and for that purpose
shall refer to the several Figures on the annexed Sheet of Drawings, the
same letters of reference indicating corresponding parts in all the
Figures.
Figure 1 of my Drawings represents a longitudinal section of a portion
of a locomotive engine with my Invention applied to the fire-box or
furnace; Figure 1ª is a transverse section of the same; and Figure 2 is
a horizontal section with some of the fire-bars removed.
"
Figures 3, 3, and 4, are similar views to Figure 1, illustrating modifi-
cations of my Invention.
A is the furnace or fire-box; B, B, are the fire-bars; C, C', arc tho
bearing bars; D is the ash-pan.
The fire-bars B, B, are made hollow with two channels a, b, but in
lieu of forming each bar in two lengths, as described in the Specification
of my said former Letters Patent, I construct it in a single length, as
shewn in the accompanying Drawings, and I make the ends of a curved
or recessed form, as shewn at c, c, so as to admit of a current of cold air
passing through the bars at a velocity proportionate to the speed at
which the engine is running, whereby the clinker is prevented from

page_text: adhering to the fire-bars, and the liability is obviated of the fire-bars
being burnt away with the molten slag.
In order to direct the air into the fire-bars I form or fit the bearing
bars C, C³, with doors d, d', or projections. which have the effect of
catching or intercepting the current of air due to the motion of the
engine, and causing it to enter the fire-bars as before mentioned.
When doors are employed, as in the examples shewn in the Drawing,
they are opened and closed as required by the aid of levers and con-
nections e, et. If the engine is running in the direction indicated by
the arrows the door d¹ will be open, whilst the door d is closed, and the
converse when the engine is travelling in the opposite direction. The
bearing bars C, C', are also made hollow and are fitted with pipes f, f.
Figures 1, 1, and 2, as described in my said former Specification,
through which the air is admitted into the fire-bars B, B, in the manner
herein-before described, is conducted and discharged into and amongst the
fire in the fire-box A, but according to my present Invention I enclose.
each of the pipes f,f, in a tube f', into which water is admitted from the
boiler for the purpose of protecting the pipes against the action of the
action of the heat. These water jacket tubes are fixed to the sides.o', c',
of the fire-box, and apertures closed by plugs 9, 9, are provided in the
plates E, E, of the boiler for the facility of removing any deposit which
may collect at the inlets into the tubes f', f'. I also attach to each of
the water jacket tubes f¹, f¹; an elbow pipe h which pipes serve to
direct the air into the centre of the fire in order for it to mingle with
the gases, whereby combustion is promoted and the fire is prevented
from lifting with the action of the blast pipe.
When the air pipes f, f, are used without the water jackets ƒ³, ƒ¹;
they may be fixed to the end plates E, E, of the boiler and the sides c', c',
of the fire-box, as shewn in Figure 3, for the purpose of admitting air
from the fire-bars B, B, to such air pipes through conducting chambers
or channels i, i, (Figures 3 and 3") provided at the exterior of the boiler,
the deflecting elbow pipes h, h, being also attached to the sides of the fire-
box, as shewn. Or in lieu of arranging the chambers or channels i, i, out-
side the boiler, they may be constructed at the exterior of the partitions-F, F,
as shewn in Figure 4, so as to be enclosed between such partitions and
-the-sides-c²,-c!,_of_the_fire-box, in which case projecting deflectors.h, h,
may be substituted for the deflecting-clbow pipes. The chambers i, i,

page_text: may be subdivided if required by vertical cross partitions, so as to form
a series of channels for the passage of the air.
The ash pan D of my improved furnace is provided with two
doors k, k³, situate one at each end, and which are pivotted at ³ in such
a manner as to admit of their being turned or swivelled by the aid of 5
suitable levers and connections 2, A, for the admission of a current of air,
the direction of which may thus be regulated at will so as to cause it to
impinge upon the fire-bars at any required part. The air thus passes
into the ash pan at a velocity proportionate to the speed at which the
engine is running, and consequently acts as a blast at the bottom of the 1
fire. The doors k, k', similarly to the doors d, d', are respectively
opened and closed according to the direction in which the engine is
travelling.
I further provide at the front and back of the ash pan D projections
or mouth-pieces m, m', respectively which are fitted so as to catch or 1
intercept the air and act as a jet to the fire, whereby sufficient blast is
obtained to assist in the generation of steam without the necessity for
contracting the blast pipe of the engine. The blast pipe may thus bo
made of a sufficiently large diameter to prevent the fire from passing
through the tubes into the smoke box and out of the chimney, whereby 2
an economy in the consumption of fuel is effected.
Some further improvements which form part of my Invention are
illustrated in Figure 1 and 1ª of my Drawings. n, n, arc water tubes fitted
within the fire-box A, and communicating at both ends with the water
of the boiler. These tubes (any required number of which may 2
space
be employed) may be arranged, either in an angular direction extending
from the crown o of the fire-box to the sides c³, c³, as shewn in the Drawing
(which arrangement I prefer), or transversely, and be made of a curved
shape or otherwise, their object being to provide additional heating
surface, and at the same time serve as supports, whereby the stays 3
ordinarily required may be wholly or partially dispensed with; p is a
plate which I fix at a short distance above the crown o of the fire-box
for the purpose of preventing the water from rising by the ebullition at
the upper mouths of the tubes n, n, so as to expose the surface of the
crown of the fire-box to the action of the fire and cause the boiler to 8
prime rapidly. This plate, similarly to the tubes n, n, also serves as a
stay or support for the fire-box, for which purpose it is attached to tho

page_text: crown o by means of screw bolts q and nuts r, by turning which-latter
the degree of tightness with which the crown o and plate pare con-
nected together may be accurately adjusted. The plate p further serves
as a collector for the sediment or deposit which may arise from the water,
and which is thus prevented from settling. upon the crown of the fire-
box or upon the tubes. The plate p may be employed separately from
the water tubes n, n, or in combination therewith as desired.
.. Having now described and particularly ascertained the nature of my
said' Invention, and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that which I, consider
to be novel and original, and therefore claim as the Invention secured
to me by the herein-before in part récited Letters Patent is,―
•
1st. The application and use of hollow fire-bars, each constructed in
one length, and with the ends curved or recessed for the admission of
5 air, substantially and for the purpose herein-before described.
'
2ndly. The combination with fire-bars constructed in the manner
before mentioned of hollow bearing bars having inclined projections or
doors for the purpose of catching or intercepting the air and directing it
into the fire-bars, substantially as herein-before described.
3rdly. The combination with hollow fire-bars and hollow bearing bars
of deflecting air pipes surrounded and protected by water jacket tubes,
substantially as herein-before described.
4thly. The employment in combination with hollow fire-bars and
hollow bearing bars of external or partitioned air chambers or channels
5 communicating with the fire-bars, and of deflecting air pipes or passages
leading from such chambers or channels into the fire-box, substantially
as herein-before described.
5thly. The constructing the ash pans of furnaces with projections
or mouth-pieces and swivelling doors for catching or intercepting
) currents of air and regulating their direction beneath the fire-bars,
substantially as and for the purpose herein-before described.
•
6thly. The general arrangement and combination of apparatus for
catching or intercepting currents of air and directing the same beneath,
into, and amongst the fire contained in a fire-box or furnace, substantially
as herein-before described and illustrated by my Drawings.

page_text: 7thly. The application and use to and in the fire-box or furnace
of a steam boiler of tubes communicating with the water space of such
boiler, substantialiy as and for the purpose herein-before described.
. 8thly. The combination with the fire-box or furnace of a steam
boiler of a plate arranged above the crown of such fire-box.or furnace, &
substantially as and for the purposes herein-before described.
9thly. The combination with water tubes fitted to the fire-box or
furnace of a steam boiler of a plate arranged above the crown of such
fire-box or furnace, substantially as and for the purpose herein-before
described.
In witness whereof, I, the said Robert Dunn, have to this my
Specification set my hand and seal, the Sixteenth day of
November, One thousand cight hundred and seventy-five.
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