IMPROVEMENTS IN FURNACES OR FIRE-PLACES AND IN APPARATUS CON- NECTED THEREWITH
Year: 1875

page_text: LETTERS PATENT to Isaac Shimwell McDougall, of the Firm of
McDougall Brothers, of Manchester and London, for the Invention
of "IMPROVEMENTS IN FURNACES OR FIRE-PLACES AND IN APPARATUS CON-
NECTED THEREWITH."
Sealed the 23rd November 1875, and dated the 17th September 1875.
PROVISIONAL SPECIFICATION left by the said Isaac Shimwell
McDougall at the Office of the Commissioners of Patents, with
his Petition, on the 17th September 1875.
I, ISAAC SHIMWELL MCDOUGALL, of the Firm of McDougall Brothers,
of Manchester and London, do hereby declare the nature of my said
Invention for "IMPROVEMENTS IN FURNACES OR FIRE-PLACES AND IN APPARATUS
CONNECTED THEREWITH," to be as follows:
-
My Invention relates more particularly to that description of furnaces
or fire-places in which what are known as mechanical stokers are
employed, and it has especial reference to the arrangement of fire-bars and

page_text: apparatus, in respect of which Letters Patent were granted to me
August 10th, 1874, No. 2759.
The first part of my Invention relates to moveable fire-bars for
furnaces or fire-places. In fire-bars, as ordinarily arranged; considerable
difficulty is experienced in maintaining the bars in a cool condition so
as to prevent them from being destroyed under the action of the exces-
sive heat to which they are exposed. In order to remedy this defect it
has been proposed to construct the bars (which are then made of
increased width and depth) hollow for the circulation-of-cold-water-
therein. Now according to my Invention I make the fire-bars of
increased depth and width as in the case of the hollow bars for water circu-
lation, but in lieu of forming the bars hollow I make them solid, whereby
I dispense with the water circulation and utilize the bulk and volume of
the metal provided by the massiveness of the bar as a conductor of cold.
to maintain the whole of the bar at an approximately equable tempera-
ture. Or in lieu of the preceding arrangement I cast the bars hollow
and fill the internal chamber of the bar with iron filings or borings,
wrought iron, or other suitable solid substances.
-
'
My Invention consists, secondly, in constructing the portion of the
fire-bars which projects from the front of the fire-place, as described
in the Specification of my said former Patent, of a peculiar shape for
the purposes herein-after mentioned.
In carrying out this part of my Invention I make that portion of the
bar which rests upon the eccentricated shaft which actuates the bars
with an open slot of an inclined or bevelled form for fitting upon the shaft,
whereby the bars are caused to move downwards as well as upwards
when the eccentricated shaft is in motion, and I dispense with the
straps on the under side of the shaft which is thus left clear and free to
admit of the cleaning and oiling being effected with facility whilst the
shaft is in motion.

page_text: My Invention relates, thirdly, to improvements in the hoppers of
mechanical stokers, and consists in making the bottom of the hopper in
two or more portions, the lower end of one of which is made of a
stopper or equivalent form, and so perforated as to allow of the passage
of air through the lower portion of this part of the hopper, and so as to
ensure the fuel when once lighted falling on to the bars in an ignited
state. This portion of the hopper is so fixed, that it may be readily
removed by hand to give free access to the fire-place when necessary.
The upper portion, or one of the upper portions, of the bottom of the
hopper is maintained in motion in a slanting direction by a crank or
eccentric or other suitable mechanical means, so that the feeding of the
fuel can be regulated to the bars as desired. This portion of the hopper
is pivotted or adjusted in such a manner as to admit of its being
readily raised to allow of the passage of a poker or rake when
desired.
I also propose to apply outside the perforations or air spaces of the
bottom plate of the bottom of the hopper a reflecting plate which is
suspended so as to protect the firemen from the heated currents issuing
from the perforations or air spaces.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Isaac Shimwell M°Dougall in the Great Seal Patent
Office on the 14th March 1876:
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ISAAC
SHIMWELL M*DOUGALL, of the Firm of McDougall Brothers, of Man-
chester and London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventeenth day of September, in the
year of our Lord One thousand eight hundred and seventy-five,
in the 39th year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Isaac Shimwell McDougall,
Her special license that I, the said Isaac Shimwell McDougall, my
executors, administrators and assigns, or such others as I, the said
Isaac Shimwell McDougall, my executors, administrators, or assigns,
should at any time agree with, and no others, from time to time

page_text: 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 Ohannel Islands, and
Isle of Man, an Invention for "IMPROVEMENTS IN FURNACES OR FIRE-PLACES
AND IN APPARATUS CONNECTED THEREWITH," upon the condition (amongst
others) that I, the said Isaac Shimwell McDougall, my 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 performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar. months next and immediately after the date of the said Letters
Patent.
--4
NOW KNOW YE, that I, the said Isaac Shimwell M'Dougall, do
hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained 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 or fire-places in which what are known as mechanical stokers 2
are employed, and it has especial reference to the arrangement of fire-
bars and apparatus, in respect of which Letters Patent were granted to
me, August Tenth, 'One thousand eight hundred and seventy-four,
No. 2759, although also applicable to other descriptions of apparatus.
My Invention relates, first, to moveable fire-bars for furnaces or fire- ;
places, and secondly, to the construction of automatic feeding hoppers
for mechanical stokers.
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, a
the same letters of reference indicating corresponding_parts_in_all_the
Figures.

page_text: Figures 5 and 6 represent respectively a front elevation and longi-
tudinal section of a portion of a boiler furnace with my improved
construction of feeding hopper applied thereto, and Figures 7, 8, 9, and
10 are details which will be herein-after referred to.
In fire-bars as ordinarily constructed and arranged considerable
difficulty is experienced in maintaining the bars in a cool condition so
as to prevent them from being destroyed under the action of the exces-
sive heat to which they are exposed. In order to remedy this defect it
has been proposed to construct the bars (which are then made of
increased width and depth) hollow so as to form a passage or chamber
therein, as shewn at A, Fig. 1, for the circulation of cold water in
order to keep them cool. Now according to my Invention, as illus-
trated by Figs. 2, 3, and 4, I make the fire-bars of increased depth
and width, the proportion being about the same as those employed in
the construction of hollow bars for water circulation, but in lieu of
forming the bars hollow I make them solid; as shewn in the transverse
section, Fig. 4, whereby I dispenso with the water circulation and
utilize the bulk and volume of the metal provided by the massiveness
of the bar as a conductor of cold, to maintain the whole of the bar at
an approximately equable temperature. Or in lieu of the preceding
arrangement I cast the bars hollow, similar to that illustrated by
Fig. 1, and fill the internal chamber A with iron filings or borings,
wrought iron, or other suitable solid substances, by which means the bar
will (as in the case of the solid bar above described) be maintained at
an approximately equable temperature. I have found the bars to
answer well in practice by constructing them of a width at the top of
from about 2 to 3 inches, and of a depth at the centre of from about
5 to 7 inches, but I do not confine myself to these dimensions.
Another improvement in the construction of fire-bars is illustrated.in
Figs. 2 and 6. On the under side of the portion B of the bar which
projects beyond the front of the fire-place when in position, as described
in my said former Specification, and shewn in Figs. 5 and 6 of the
Drawings hereunto annexed, I make an open slot C of an inclined or
bevilled form for fitting upon the eccentricated shaft D which actuates
the bars, whereby such bars are caused to move downwards as well as
upwards when the eccentricated shaft is in motion. This arrangement
admits of the straps hitherto employed on the under side of the shaft
being dispensed with, whereby the shaft is clear and free to allow of

page_text: recesses or concavities for the purpose of contributing to maintain the
bars in a cool condition.
My Invention relates secondly to improvements in the hoppers of
mechanical stokers. A difficulty has hitherto been experienced in the
employment of mechanical stokers from the fact that they do not start
and continuously maintain the fuel in an ignited state when it enters
upon the bars. The attainment of this object is very important, because
if the fuel is not delivered upon the bars in an ignited state, and it be
allowed to travel on the bars in an unignited condition, a large surface
of the steam raising portion of the bars is lost. In order to avoid this
difficulty mechanical stokers are in operation, which by arrangements of
rollers and fans are caused to grind and then throw on the fuel in even
and regular quantities over the surface of the bars. Other mechanical
stokers are used in which the coal is allowed to enter on the front end
of the bars in an ignited state from combustion chambers composed of
fire-bricks and tiles, which deflect upon the cold fuel, and cause it to
burn and coke before it enters upon the bars proper. These arrange-
ments require considerable time and labour before the brickwork attains
sufficient heat to prepare the fuel for delivery to the bars. Now in
carrying out this part of my Invention I construct the bottom of the,
-hopper-F in two-parts-G-and. H, Figs. 5 and 6, the lower part G. of
which (shewn in-detail-in-Figures 7, 8, 9, and 10) is made of a stepped
or equivalent form, as at I, K, and provided with perforations or slots L
··to allow of the passage of air through the lower portion of this part of
the hopper, and thereby ensure the fuel when once lighted falling on to
the bars in an ignited state. M, M, are pins or projections provided on
the opposite ends of the part G, which pins maintain the part in position
by entering slots N in the cheeks ○ of the hopper in such a manner as
to be capable-of-being-readily-removed to give free access to the fire.

page_text: place when necessary. An opening P is provided in the part G to
admit of the introduction of a poker if necessary without removing the
part G out of position. The steps I and K may be either formed in one ¨
with the part G, as shewn, or the upper step K may be a separate piece
secured in any suitable manner so as to rest upon the lower step I.
The step K supports the greater portion of the weight of the green fuel,
and prevents it impeding the draught, which it would do if allowed to
fall too quickly on to the step I containing the slots L. The upper
portion H of the bottom of the hopper is maintained in motion in a
slanting direction by the crank or eccentric Q carried on the shaft D and
by the connecting rod R, or it may be actuated by any other similar
mechanical means, so that the feeding of the fuel to the bars can be
regulated as desired. On the opposite ends of the part H there are
provided pivots S, S, which enter slots T in the cheeks O, and hold the
part H in place in such a manner as to admit of its being readily
raised or adjusted to allow of the passage of a poker or rake when
desired.
A plate of metal may if required be suspended outside the perforations
or slots L in the part G, so as to protect the firemen from the heat
issuing from such perforations.
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 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 mode or method of maintaining the bars in an approxi-
mately cool condition by the utilization of the mass or solid contents of
the bars as a conductor of cold, substantially as herein-before described.
Secondly. Constructing that portion of the bars which rests upon the
eccentricated shaft with an inclined or bevilled open slot, so as to admit
of the bars receiving a downward as well as an upward motion when the
shaft is in revolution without the employment of metal straps, sub-
stantially as herein-before described and illustrated by my Drawings.
Thirdly. Providing increased air space between the bars immediately
beyond the eccentricated shaft by forming a recess on the opposite sides
of the bars at this part, substantially as and for the purpose herein-
before described and illustrated by my Drawings.

page_text: Fourthly. Constructing the bottoms of the hoppers of mechanical
stokers in two or more parts, one or more of which is or are maintained
stationary, and provided with apertures for the admission of air, whilst
the other is maintained in motion, substantially in the manner and for
the purpose herein-before described and as illustrated by my Drawings.
"
In witness whereof, I, the said Isaac Shimwell M°Dougall, have
to this my Specification set my hand and seal, the Eighth day
-of-March,-One-thousand eight hundred and seventy-six.
---
ISAAC SHIMWELL M°DOUGALL. (L.S.)