IMPROVEMENTS IN FURNACES OR FIRE-PLACES, AND IN APPARATUS CONNECTED THEREWITH
Year: 1876

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 CONNECTED THEREWITH."
PROVISIONAL SPECIFICATION left by the said Isaac Shimwell McDougall
at the Office of the Commissioners of Patents on the 7th March 1876.
ISAAC SHIMWELL MCDOUGALL, of the Firm of McDougall Brothers, of Manchester.
and London, "IMPROVEMENTS IN FURNACES OR FIRE-PLACES, AND IN APPARATUS
CONNECTED THEREWITH."
My Invention relates more particularly to improvements in the furnaces or fire-
places and apparatus connected therewith, for which Letters Patent were granted to
me, and dated respectively August 10th, 1874, No. 2759, and September 17th, 1875,
No. 3256, but it is also applicable to other descriptions of apparatus.
It is desirable that when mechanical stokers are employed for furnaces that they
should be so constructed that on the occasion of any stoppage of the motive power
hand firing may at once be resorted to. In order to attain this object I provide
metal blocks or supports at the mouth of the furnace, underneath the hoppers of
the mechanical stoker, and hinge thereto a door or doors at a sufficient distance from
the furnace front to enclose and cover the lower portion of the hopper bottom. On
the inside surface of these supports slots or concavities are provided for the recep-
tion of the pivots which support the removeable stepped portion or portions of the
hopper bottom described in the Provisional Specification to my last-mentioned Letters
Patent. These pivots and the slots in the supports are so arranged that the whole
of the lower portion of the hopper bottom may be lifted out at once, leaving sufli-
cient space for free access to the front of the fire-place for the purposes of hand-
firing, the doors remaining in position.
I support that portion of the hopper bottom of the mechanical stoker, described
in my said former Provisional Specification, which is maintained in motion in a
slanting direction upon friction rollers carried on studs in the checks of the hopper,
and I form on the upper surface of this part a series of ribs or projections, which
extend across the hopper and serve when in motion to increase the agitation of the
fuel. also arrange over the feed entrance of the furnace a vertically adjustable
plate, the lower end of which is angled or made to incline towards the hopper.
ר ...

page_text: This plate is provided for the purpose of enabling the supply of fuel from the hopper
to the furnace to be regulated as required or entirely cut off when hand firing is
resorted to. The position of this plate may be regulated by means of an adjusting
screw, or by any other suitable mechanical contrivance.
Another part of my Invention consists of means for preventing the speedy
burning away of the inner ends of the fire-bars. In order to effect this object I
support the inner ends of the bars on blocks of metal or bearers of maximum
dimensions, and I utilize the bulk or volume of the metal provided by their mas-
siveness as a conductor of cold. The inner ends of the bars are made of an angular
form, and bear upon a similarly formed surface on the metal blocks or bearers, which
latter are so fixed that the fire can only pass over and beyond them whilst cool air
is allowed to circulate beneath them, whereby they are maintained at an approxi-
mately equable temperature.
I also make the top surface of the bars of a somewhat curved form, so that the
centre is higher than the two ends.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Isaac Shimwell McDougall in the Great Seal Patent Office on the 30th
August 1876.
ISAAC SHIMWELL MCDOUGALL, of the Firm of McDougall Brothers, of Manchester
and London. "IMPROVEMENTS IN FURNACES OR FIRE-PLACES, AND IN APPARATUS
CONNECTED THEREWITH."
My said Invention relates more particularly to improvements in the mechanical
stokers employed in connection witli furnaces or fire-places, for which Letters Patent
were granted to me dated respectively August 10th, 1874, No. 2759, and
September 17th, 1875, No. 3256, but it is also applicable to other descriptions of
apparatus employed for a similar purpose.
One part of the present Invention has for its object providing facilities for hand
firing in the event of derangement of the feeding mechanism. In order to attain
this object I arrange at the mouth of the furnace, underneath the hoppers of the
mechanical stoker, a frame fitted with a door or doors and made to extend a suffi-
cient distance from the furnace front to enclose the lower portion of the hopper
bottom. Slots are provided on the inside of the cheeks of this frame for the recep-
tion of pivots which support the removeable portion or portions of the hopper
bottom, described in the Specification to my last-mentioned Letters Patent. These
pivots and the slots are so arranged that the whole of the lower portion of the
hopper bottom may be lifted out without deranging the other parts of the apparatus,
leaving sufficient space for free access to the front of the fire-place for the purpose of
hand firing, the frame with the doors remaining in position.
I support that portion of the hopper bottom of the mechanical stoker, described in
my last-mentioned former Specification, which is maintained in motion in a slanting
direction upon friction rollers carried on studs in the checks of the hopper, and I
form on the upper surface of this part a series of ribs or projections, which extend
across the hopper and serve when in motion to increase the agitation of the fuel. I
also arrange over the feed entrance of the furnace a vertically adjustable plate for
the purpose of enabling the supply of fuel from the hopper to the furnace to be
regulated as required or entirely cut off when hand firing is resorted to.
Another part of my Invention relates to means for preventing the rapid burning
away of the inner ends of the fire-bars, and consists in supporting the same on
blocks of metal or bearers of maximum dimensions, whereby I utilize the bulk or
volume of tho metal provided by their massiveness as a conductor of cold. The
inner ends of the bars are made of an angular form and bear upon a similarly
formed surface our the metal blocks or bearers, which latter are so fixed that the fire

page_text: can only pass over and beyond them whilst cool air is allowed to circulate beneath
them, whereby they are maintained at an approximately equable temperature.
I also make the top surface of the bars of a somewhat curved form, so that the
centre is higher than the two ends.
And in order that my said Invention may be fully understood I shall now pro-
ceed 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 the accompanying Sheet of Drawings is a longitudinal vertical section
of a portion of a boiler furnace with my improvements applied thereto, and the
remaining Figures represent portions of the mechanical stoker and furnace detached,
and will be herein-after referred to.
A represents a portion of a boiler having fitted to the front end thereof a hopper
B for containing the fuel with which the furnace C is supplied, in the manner
herein-after described. The bottom of this hopper consists of four parts D, E, F, G,
three of which, videlicet, those D, E, F, are shewn detached at Figures 2, 3, and 3a,
respectively. The part D is provided on its upper face with ribs or projections a,
and is supported on friction rollers b mounted on studs carried by the checks of the
hopper. This part D is caused to move to and fro in an inclined direction, whereby
the fuel contained in the hopper is agitated and caused to descend on to the part E,
thence on to the part G into the furnace. The ribs or projections a serve to increase
the agitation of the fuel and prevent it from caking in the hopper. Motion is
imparted to the part D from the eccentricated shaft H which actuates the fire-bars
by means of an eccentric I, the rod K of which is connected to one arm of a bell
crank lever L, whilst the other arm of such lever connected by a link M to tho
upper end of the part D of the hopper bottom, as described in my last-mentioned
former Specification. In order to regulate the passage of fuel from the hopper into
the furnace I fit to the interior of the hopper a sliding plate N, the height of which
may be regulated as required, the plate when adjusted being fixed in position by
means of a pin passing through the lug O into one of a series of holes provided in
the bar P. The lower end of the plate N is so shaped as to incline downwards, as
shewn at P¹, towards the part D of the hopper bottom, against which it is caused to
bear when in its lowest position, so as to entirely cut off the supply of fuel to the
furnace.
The removable portions E, F, G, of the hopper bottom are provided with journals
or pivots e fitting into slots d formed in two strong metal checks Q, one only of
which is shewn in my Drawings, bolted to the front of the boiler or furnace, and
also to the cheeks R of the hopper, as shewn at S in Figure 4. The cheeks Q are
connected together at the top and bottom by bars T, U, as shewn in Figures 5 and 6,
and have attached to their outer ends by hinges v, doors V, shewn open in Figure 1,
which when closed abut against the bars T, U, and prevent the adinission of air to
the furnace, a valve W being provided in the doors for the purpose of admitting air
to the furnace when required.
If from any cause it be requisite or desirous to feed the furnace by hand the parts
E, F, and GC, of the hopper bottom may be readily removed by raising their pivots c
out of the slots d, an opening or space thereby being made through which the fuel
may be passed by hand into the furnace by opening the doors V.
In order to prevent the rapid burning away of the inner ends of the fire-bars Y,
I make the bearers X which support the inner ends of the bars of maximum dimen-
sions, whereby the volumn of metal provided by their massiveness is utilized as a
conductor of cold. The bearers may either be made solid, as shewn in Figure 1, or
in two parts, as shewn in the modification, Figure 7. The inner ends of the bars
are formed with an inclined surface Z, which bears upon a corresponding inclined
surface e formed on the bearer X, and I fit to the back portion of the ash-pit a
hinged door f having perforations f¹ for the purpose of causing the body of cold air
entering the ash-pit to circulate beneath the bars whilst allowing a small portion of
such cool air to pass beneath the bearers, whereby these parts are maintained at an

page_text: approximately equable temperature. I also form the bars Y with their central
portion higher than their ends h, h, as shewn in Figure 8, the dotted line g¹, g, 9',
indicating the horizontal plane touching the centre of the bar from which the ends
,, diverge. By means of this arrangement the tendency to a sinking in the centre
of the bars is obviated, and much greater durability is obtained.
Having now described and particularly ascertained the nature of my said Inven-
tion, 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. Providing beneath the hoppers of mechanical stokers a fime carrying the
removable portion of the hopper bottom, and fitted with doors, for the purpose of
facilitating the feeding of the furnace by hand when necessary, substantially as
herein before described and illustrated by my Drawings.
Second. Constructing the moving portion of the hopper bottom with ribs or pro-
jections for the purpose of agitating the fuel contained in the hopper, and supporting
such moving portions upon friction rollers mounted on studs in the cheeks of the
hopper, substantially as herein-before described and illustrated by ny Drawings.
Third. The mode or method of maintaining the inner ends of the fire-bars in an
approximately cool condition by supporting them upon bearers of maximum dimen-
sions and utilizing the mass of the bearers as a conductor of cold, substantially as
herein-before described.
Fourth. Constructing the fire-bars with their upper surface curved longitudinally
or with their central portion higher than their ends, substantially as and for the
purpose herein-before described.
In witness whereof, I, the said Isaac Shimwell McDougall, have to this my
Specification set my hand and seal, this Twenty-fourth day of August One
thousand eight hundred and seventy-six.
ISAAC SHIMWELL M'DOUGALL. (L.S.)