IMPROVEMENTS IN FIRE-BAR3, AND IN THE MODES OF OPERATING THE SAME
Year: 1874

page_text: LETTERS PATENT to Isaac Shimwell M Dougall, of the Firm of
M Dougall Brothers, of Manchester and London, for the Invention
of "IMPROVEMENTS IN FIRE-BAR3, AND IN THE MODES OF OPERATING THE
SAME."
Scaled the 3rd February 1875, and dated the 10th August 1874.
PROVISIONAL SPECIFICATION left by the said Isaac Shimwoll
M* Dougall at the Office of the Commissioners of Patents, with
his Petition, on the 10th August 1874.
I, ISAAC SHIMWELL M° DOUGALL, of the Firm of Mª Dougall Brothers,
of Manchester and London, do hereby declare the nature of my said
Invention for "IMPROVEMENTS_IN_FIRE-BARS, AND IN THE MODES_OF_OPERATING.
THE SAME," to be as follows :-
My Invention relates to an improved arrangement and construction
and.mode of operating the fire-bars of. furnaces, steam boilers, and fire--
places, and has for its object continuously feeding the fuel into the fire-
place, and continuously removing the clinker or dross therefrom so as to
obviate the waste of fuel and loss of heat arising from the opening of

page_text: the firc-door and slackening of the firo necessary for enabling the stoker
to loosen and remove the slag or clinker from the bars, and at the same
time more effectually consume the smoke arising in the furnace or fire-
place.
My Invention consists in making the fire-bars or sets of fire-bars
somewhat longer than the furnace or fire-place, and so fitted in the latter
that each bar or set of bars may move in a contrary direction to the
neighbouring or adjacent bar or set of bars. By any suitable mechanical
means I cause cach bar or set of bars to move upward and downward
and forward and backward, so that when moving forward, that is, toward
the bridge of the fire-place, it may also move upward, and when moving
backward, that is, toward the front, it may also move downward, and so
that whilst one bar or set of bars is moving forward or upward tho
neighbouring or adjacent bar or set of bars may be moving backward
and downward. To the front of the fire-place I attach a hopper or
mechanical feeder, which allows the fuel to continuously feed tho bars
without admitting an undue amount of cold air. The motions of the
bars above described carry the fuel forward with a constant spreading
effect, and the chief portion is consumed before it can reach the end of
the bars. The bridge wall is so situated as to overlap the end of the
bars at both sufficient height and distance to allow of the continuous
exit of clinker or dross, and to allow of the admission of the required
amount of air warmed by passing under the fire-place to combine with
and complete the combustion of the smoke arising in the fire-place.
The great advantage of my Invention is that in removing the slag or
clinker by its means an uniform state of heat in the furnace is main-
tained with economy of fuel and utilisation of smoke.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
"
filed by the said Isaac Shimwell Mª Dougall in the Great Scal Patent
Office on the 10th February 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ISAAC
SHIMWELL M° DOUGALL, of the Firm of M Dougall Brothers, of Man-
chester and London, send greeting.
30

page_text: WHEREAS Her. most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of August, in the year
of our Lord One thousand eight hundred and seventy-four, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
5 cessors, give and grant unto me, the said Isaac Shimwell Ms Dougall;
Her special license that I, the said Isaac Shimwell McDougall, my
executors, administrators, and assigns, or such others. as I, the said
Isaac Shimwell Me Dougall, my executors, administrators, or assigns;
should at any time agree with, and no others,. from time to time
O and at all times thoreafter 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 Islo
of Man, an Invention for "IMPROVEMENTS IN FIRE-BARS," upon the con-
dition (amongst others) that I, the said Isaac Shimwell M* Dougall, my
5 executors or administrators, by an instrument 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 per-
formed, and cause the same to be filed in the Great Seal Patent. Offico
within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said Isaac Shimwell McDougall, do
hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained.
in and by the following statement, reference being had. to the accom
panying Drawings and to the letters and figures marked thereon, that is.
to say :-
My said Invention relates to an improved mode of constructing,
arranging, and operating the fire-bars of furnaces, steam boilers, and
fire-places, and has for its object continuously feeding the fuel into the.
1 fire-place, and continuously removing the clinker or dross therefrom so
as to obviate the waste of fuel and loss of heat arising from the opening
of the fire-door and slackening of the firo necessary for enabling the.
stoker to loosen or remove the slag or clinker from the bars, and at the.
same time to more effectually consume the smoke arising. in the furnace.
or fire-place.
My Invention consists in making the fire-bars or sets of fire-bars
somewhat longer than the furnace or fire-place, and so fitting them in,
the latter that each bar or set of bars may move in a contrary direction.
:

page_text: to the neighbouring or adjacent bar or set of bars. By any suitable
mechanical means I causo cach bar or set of bars to movo upward and
downward and forward and backward, so that when moving forward,
that is, toward the bridge of the fire-place, it may also movo upward,
and when moving backward, that is, towards the front, it may also movo
downward, and so that whilst one bar or set of bars is moving forward
and upward the neighbouring or adjacent bar or set of bars may bo
moving backward and downward. To the front of the fire-place I attach
a hopper or mechanical feeder, which allows the fuel to continuously.
feed the bars without- admitting an undue amount of cold air. Tho
motions of the bars above described carry the fuel forward with a
constant spreading effect, and the chief portion is consumed before it
can reach the end of the bars. The bridge wall is so situate as to overlap
the end of the bars at both sufficient height and distance to allow of the
continuous exit of clinker or dross, and to allow of the admission of
the required amount of air warmed by passing under the fire-place to
combine with and complete the combustion of the smoke arising in the
fire-place.
Tho great advantage of my Invention is that in removing the slag or
clinker, by its means a uniform state of heat in the furnace is main-
tained with economy of fuel and utilization of smoke.
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.
My Invention is suitable for and can be adapted to the fire-places of
differently constructed boilers and furnaces. In describing a method in
which the Invention may be carried out, I show it as applied to a two-
flued steam boiler which is the kind of fire-place in which I believe it.
will prove most effective and useful. The principle may however bo
applied to other constructions of boilers and furnaces, the mechanical
arrangements and details being modified accordingly in a manner that
will be well understood by persons conversant with this class of
apparatus.
Figure 1 of my Drawings represents a sectional elevation of a portion
of a steam boiler showing the fire-bars arranged in a fluc in accordance
1

page_text: "
Figure 2 is a corresponding plan of the fire-bars fitted in one flue, the
other flue being represented with the bars removed.
.
Figure 3 is an end view of the boiler, shewing the fire-bars arranged
in one of the flues, the other flue being intended to be fitted in a similar
manner, and Figure 4 is a plan corresponding to Figure 8, but with the
bars shewn in both flues; A is the boiler; B are the flues; C, the
movable fire-bars; C³, side or stationary fire-bars; D is a rack or bovil
fluted roller; E, an eccentricated shaft; F, the feed hopper; G, the bridge
wall; H, a casting fixed to the boiler for supporting the hopper and
brackets; I, brackets bolted to the plate H for supporting the eccent-
ricated shaft E.
The movable fire-bars C are made of sufficient length to pass under
the front of the hopper F at one end, and under the bridge wall G at
the other end. The front end C³ of each bar is fitted on the eccentric
shaft E, to which a strap C³ is screwed for retaining the bars on the shaft.
Underneath the bar at a short distanco from the end, there is cast a
bevel lug piece O', to fit on to the fluted roller D. On one side of the
bar there are formed several ribs or shoulder picces C³, of a suitablė
depth to maintain an air space between the bars. The side bars O' are
castings made to fit against the sides of the flue, and they are supported
by resting upon notches on the bridge wall G and the front plate H.
On the side bars C', at a short distance from the back end, there is cast
a bracket K, with a slot hole, such brackets forming bearings for the
fluted rollers D. These rollers, which may be composed of steel, cast
iron, or other suitable material, are supported on their axes by shafts L,
which revolve in the brackets K of the side bars C'. The shaft E
is composed by preference of wrought Bessemer steel; and it is turned
up on three different centres; those portions which are turned from the
true centre form the ends of the shaft and those parts which revolve in
the bearings; the other portions of the shaft are turned from different
centres opposite each other, each at a suitable distanco from the truó
centre, at given distances alternately, and form eccentric-pieces-E!;
Figures 2 and 3, on which are fitted the ends 03 of the fire-bars, which
with the strap C³ form an eccentric. On one end of the shaft E is
placed a pulley or spur wheel-M,-by-which it is connected to motive
power. When motion is given to the shaft, each bar is caused to move
in a direction opposite to the adjacent, bar, one portion of the bars
rushing upwards and forwards, and the other moving downwards and

page_text: -
backwards; the same motion is continued to the end of the bars by
means of the lug piece O*, revolving the fluted roller D. Those of the
bars which are moving forwards revolve the fluted roller with them,
while those moving in the contrary.direction place their notches behind
another flute of the roller, and in returning, tho bar brings forward the
flute with it; by this means the roller D is kept continuously revolving,
giving an eccentric motion to the opposite end of the bars, similar to
that imparted to their.end C³ by the shaft E..
The hoppers F are constructed of several loose cast-iron plates, the
side pieces of which are bolted firmly to the cast front plate H. Tho
bottom and end plates are fixed in such a manner as to admit of their
being readily removed if it is necessary to draw out the fire speedily. In
the end plate of the hopper there is placed a small slide door F, through
which a rake or poker may be passed into the fire-place when required.
When the space over the bars for feeding the fuel is limited, the
bottom of the hopper is by preference made so as to have a shaking
movement by allowing the front end of the plate to rest on the bars, the
back end of the plate working on pivots attached the side of the
hopper.
The bridge wall G is composed of brickwork and cast iron, and should a
overlap the bars to a slight extent, as shewn at N, sufficient spaco being
left between the lowest part of the overlap N of the bridge wall G and
the surface of the bars for the delivery of the dross.
·
The cast-iron plate H is made of a suitable shape and fixed to the
front plate of the boiler A, to which are bolted the brackets I, before, 2
mentioned, for the pedestals I which bear and through which revolves
the shaft E.
It is preferred to employ some means of varying the speed at which
the bars work, which object may be effected by arranging between the
motive power and the eccentricated shaft a system of speed pulleys or g
other suitable mechanical contrivance so as to enable the bars to be
worked at a greater or less speed, as required.
The fire-bars, as shown in the Drawings, are suitable for working
burgy or engine coal, but the size and shape of the fire-bars, the width
and depth of the eccentrics, and the speed at which they work will bo- 3
varied according to the nature of the fuel used,

page_text: The same arrangement of fire-bars may be utilized in extracting
combustible elements out of minerals and other compounds.
"In preparing the fire-bars for operation the bottom and end of the
hopper F are first removed, a light hand door being used in their place.
A good fire is then made by hand to cover the whole surface of the bars,
after which the bottom and end of the hopper are replaced. A quantity
of red fire is then drawn on to the bottom plate of the hopper by means
of a hand rake passed through the slide door F' at the end of the hopper.
The hopper being then filled and kept supplied with fuel the bars are
put in motion at the speed required. The coal immediately on entering
the fire-place becomes ignited, and is regularly distributed over the
breadth and length of the fire-bars until reaching the overlap N of the
bridge wall G, where the good light portions are retained and consumed,
the heavy clinker and dross passing under the overlap of the bridge wall
is thrown out. A poker may be passed through the door F³ in the end.
of the hopper when required in order to maintain the space beneath
the bridge wall clear and free from obstruction by lumps of bass or
clinker. .
1
The advantages of my Invention are that a continuous and regular
fire is maintained over the whole surface of the bars. By means of the
movement of the bars and combustion the fire becomes thinner, more
exposed to the air, and intensely hot as it approaches the bridge wall,
whereby complete combustion of smoke and fuel is maintained without
the necessity for admitting.cold air over the fire in feeding the fuel and
removing the clinker and dross.
When applied to marine boilers the additional advantage will be
obtained of preventing the exposure of the men employed in firing to
the great heat now occasioned by the frequent opening of the fire-doors
both for throwing on fuel and clearing the bars, which in the confined
space of the stoke hole of steamers is at present a serious difficulty.
Any dust which may fall through the bars may be reintroduced
into the hopper and reburnt, nothing being rejected except the clinker
and dross, which pass under the-bridge-wall-at the end of the fire-bars.
Having now described and particularly ascertained the nature of my
said Invention, and a method of carrying the same into effect, I wish it
to be understood that I do not limit myself to the precise details herein-

page_text: before described and illustrated on my Drawings, as the same may be
varied in applying the principle of my Invention; but what I consider to
be novel and original, and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is,―
First. The application and use of fire-bars or sets of fire-bars of greater 5
length than the furnace or fire-placo, and so constructed and arranged
that cach bar or set of bars is caused to move upward and downward
and forward and backward in such a manner that when moving forward,
that is, towards the bridge of the fire-place, it may also move upward,
and when moving backward, that is, towards the front, it may also move 1
downward, and so that whilst one bar or set of bars is moving forward
and upward the neighbouring or adjacent bar or set of bars may be
moving backward and downward.
Secondly. Constructing the bridge wall of the fire-place or furnace so
as to overlap the end of the bars, substantially as and for the purposes 1
herein-before described, and as illustrated by my Drawings.
Thirdly. The combination with the before-mentioned fire-bars of a:
hopper or mechanical feeder, substantially as herein-before described and
illustrated by my Drawings.
In witness whereof, I, the said Isaac Shimwell Me Dougall, have 2
to this my Specification set my hand and seal, the Eighth day
of February One thousand eight hundred and seventy-five.
ISAAC SHIMWELL M° DOUGALL. (L.S.)