for Effecting Combustion of Fuel with Air under Pressure.
Year: 1886

page_text: Date of Application, 4th May, 1886.
Complete Left, 2nd Feb., 1887.
Complete Accepted, 18th Mar., 1887.
for Effecting Combustion of Fuel with Air under Pressure.
I, JOHN REED FOTHERGILL, of No. 1 Bathgate Terrace West Hartlepool in the
county of Durham, Superintending Marine Engineer, do hereby declare the nature
of this invention to be as follows:-
My invention has reference to furnaces or apparatus such as those of marine steam
boilers in which combustion of fuel is effected with air supplied to the furnace under
pressure, and my invention relates to the supply and admission of air to the fuel in
the furnace proper as also to the gases evolved from the said fuel in such a manner as
to ensure their more complete combustion.
The means hereinafter described are according to my invention employed where the
air for supporting combustion is supplied under pressure by any suitable means such
as by forcing it in by a fan, inducing a current by means of a jet or jets of steam, or
by both these means.
For the supply of air to the fuel I construct the grate or support on which the
fuel is burnt in one or more pieces of any suitable refractory material with a number
of small tapered circular or oval holes or other shaped passages therethrough for the
passage of air. Such a grate or perforated support may be constructed in various
forms, and of various materials, such as iron, fire-brick, or asbestos, or a combination
of such materials. When constructed in separate parts these may take the form of
an ordinary fire-bar with tapered circular or oval holes extending through it from a
point at the side, some distance below the top, to the centre of the top of the bar, or
they may be constructed as perforated cast-iron slabs strengthened with flanges or ribs
underneath. These flanges or ribs may be made with passages for the circulation of
water or air to keep the grate cool, or the slabs may be made hollow so as to form
passages through them in which air can circulate for the purpose of keeping them
cool, or perforated slabs of asbestos or fire-brick supported upon bars of iron may
be used.
In order to supply air to the gases evolved from the fuel (which I will assume to be
carbonic oxide) a pipe or pipes is or are so placed in the back or sides of the boiler as
to serve the purpose of and in lieu of an ordinary screw stay or stays.

page_text: The air on passing there-through enters a chamber perforated with circular or oval
holes or passages and which is made of any suitable refractory material such as iron,
fire-clay, asbestos, or a combination of such materials, and is situated in the combustion
chamber of the boiler in such position as to deliver small streams or jets of air upon
and cause the same to combine with the gases evolved from the fuel.
The air for this purpose is supplied to the pipe or pipes under pressure or by a
current induced by a jet or jets of steam.
The fronts or mouths of the furnaces are closed or covered with iron casings such
that air supplied under pressure into these casings can be delivered in regulated
quantities to that part of the furnace over the fuel being fed through passages or holes
in a back or inner plate of the casing and through a perforated chamber attached to
this plate on the inner side to the furnace.
The passages or holes in the plate referred to are controlled by a valve or valves to
regulate the supply and admission of air.
Air is delivered to the ash-pits (under the fire-grate) from the same casing through
special passages or holes in the lower half of the back or inner plate. These passages
are controlled by a valve or valves deriving motion from the movement of an
arrangement of door latch or fastener which is such that when it is moved to free or
unfasten the fire or furnace door it closes or partially closes the valve or valves thus
regulating or cutting off the admission of air to the furnace through the fire grate,
and by thus reducing the air supply to the furnace prevents the flame and hot gases
being forced out of the furnace when the door is opened.
When there is more than one furnace in a boiler, the casings are so arranged that
the air flows from one into and through the other in its passage to the furnaces.
There is a plate at the end of the ash-pit and under the fire-bridge which is some-
times called the "blinder-plate" and this plate is perforated with holes or it may have a
perforated door or slide fitted over a hole in the plate in such manner as to allow any
ashes &c. to he removed from behind the fire-bridge, or in lieu of this door or slide an
arrangement can be substituted of such a kind as can be completely removed to clean
behind the bridge. This apparatus is perforated with holes and has a slide or valve
fitted to shut off or regulate the admission of air through the holes.
The object of the introduction of air by jets or streams under the various conditions
herein-above described is that it may combine with the gases evolved from the fuel
without lowering their temperature as it would do if it were supplied in a volume, and
thus to effect more complete combustion with efficiency and economy.
The air might be heated by the waste gases escaping to the funnel.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.

page_text: Improvements in Marine Boiler and other Furnaces or Apparatus
for Effecting Combustion of Fuel with Air under Pressure.
I, JOHN REED FOTHERGILL, of No. 1, Bathgate Terrace, West Hartlepool, in the
County of Durham, Superintending Marine 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:-
My invention has reference to furnaces or apparatus such as those of marine steam
boilers in which combustion of fuel is effected with air supplied to the furnace under
pressure, and my invention relates to the supply and admission of air to the fuel in
the furnace proper as also to the gases evolved from the said fuel in such a manner as
to ensure their more complete combustion.
The means hereinafter described are according to my invention employed when the
air for supporting combustion is supplied under pressure by any
suitable means; such
as by forcing it in by a fan, inducing a current by means of a jet or jets of steam, or
by both these means.
For the supply of air to the fuel I construct the grate or support on which the fuel
is burnt in one or more pieces of any suitable refractory material with a number of
openings therethrough for the passage of air; such a grate or perforated support may
be constructed in various forms and of various materials such as iron, fire-brick, or
asbestos, or a combination of such materials.
When constructed in separate parts these may in one form resemble an ordinary
fire-bar.
In order to supply air to the gases evolved from the fuel (especially to the
carbonic oxide) a pipe or pipes is or are so placed in the back or sides of the boiler as
to serve the purpose of, and in lieu of, an ordinary screw stay or stays. The air on
passing therethrough enters a chamber perforated with holes or passages and which is
made of any suitable refractory material such as iron, fire-clay, asbestos, or a
combination of such materials, and is situated in the combustion chamber of the
boiler in such position as to deliver small streams or jets of air upon and cause the
same to combine with the gases evolved from the fuel. The air for this purpose is
supplied to the pipe or pipes under pressure or by a current induced by a jet or jets
of steam.
The fronts or mouths of the furnaces are closed or covered with iron casings such
that air supplied under pressure into these casings can be delivered to the ash-pits
(under the fire-grate) through special passages or holes in the lower half of the back
or inner plate. These passages or holes are controlled by a valve or valves deriving
motion from the movement of an arrangement of door latch or fastener which is
such that when it is moved to free or unfasten the fire-door it closes or partially
closes the valve or valves thus regulating or cutting off the admission of air to the

page_text: furnace through the fire-grate and by thus reducing the air supply to the furnace,
preventing the flame and hot gases being forced out of the furnace when the door
is opened.
When there is more than one furnace in a boiler the casings are so arranged that
the air flows from one into and through the other in its passage to the furnaces.
There is a plate at the end of the ash-pit and under the fire-bridge which is
sometimes called the "blinder-plate" and this plate is perforated with holes, or it may
have a perforated door or slide fitted over a hole in the plate in such manner as to
allow any ashes &c. to be removed from behind the fire-bridge, or in lieu of this door
or slide an arrangement can be substituted of such a kind as can be completely
removed to clean behind the bridge. This apparatus is perforated with holes and has
a slide or valve fitted to shut off or regulate the admission of air through the holes.
In the accompanying six sheets of illustrative drawings,
Fig. 1 shows in front elevation a marine boiler with apparatus according to my
invention applied to it.
Fig. 2 is a back elevation of the same boiler.
Fig. 3 is a longitudinal vertical section thereof, and
Fig. 4 a horizontal section.
Fig. 5 shows in longitudinal vertical section a double ended marine boiler with
apparatus according to my invention applied to it.
Fig. 6 is a vertical section in line Z Z of Fig. 5.
Figs. 7, 8, 9, and 10 are detail views.
Fig. 11 shows in vertical section part of a donkey boiler with apparatus according
to my invention applied to it, and
Fig. 12 is an elevation of such a boiler to a smaller scale.
The same numerals are used to denote the same or like parts where they occur in
the different views.
Referring to Figs. 1 to 4 inclusive, 1. is the shell of the boiler which is constructed
in the present example with three furnaces: each of these contains a grate or support
for fuel, which, to admit of the supply of air to the fuel is constructed as I prefer of a
number of parts of ordinary fire-bar section but somewhat deeper as represented in
Fig. 3, where 2, 2, are fire-bars, and 3, 3, are distance pieces cast on the sides of the
bars to determine the openings between the bars which are rivetted together in sets of
two each or more as desirable to prevent their warping or twisting, and to maintain
uniformity of distance between the bars; the rivets pass through the holes in the
distance pieces 3. Any other suitable construction of grate may however be adopted
so long as suitable openings for admission of air to the fuel to be burnt thereon be
provided. 4 is a casing that extends across the front of the boiler closing or covering
the mouths of the furnaces 5 in such a manner that air supplied under pressure as by
a fan and engine 6 into this casing can be delivered into the ash-pits 7 (under the
fire-grates 2, 2,) through the special passages or holes 8 in the lower half of the back
or inner plate 9. The passages 8 are controlled by a valve or valves 10 opened or
closed by the movement of the furnace door latch or fastener 11. When the latch 11
is pulled or knocked back against the stop 12, the forked lever 13 on the same
spindle 14 as the latch 11 and connected to the pin 15 of the valve 10 closes or
partially closes the passages 8, thus regulating or cutting off the admission of air to
the furnace through the fire-grate 2, 2, and by thus reducing or cutting off the air
supply to the furnace before the furnace door 16 can be opened, the hot gases and
flame are prevented from being forced out of the furnace when the door 16 is
opened. When the door 16 is again closed the latch 11 is pulled over towards the
door, and the arrangement as will be seen is such that the end of the latch slides over
a tapered piece of iron 17 fastened to the door in such a manner that the latch forces
and holds the door closely shut. The bottom of the piece 17 is hooked or bent to
form a handle for opening the door.
Ordinary flat disc valves 18 are provided in the lower half of the inner plate 9 so
that the air supply to the ash-pits can be more readily regulated.
The casing is constructed in sectional pieces in such a manner that the part

page_text: Covering any one furnace monen can
without removing the other parts.
De TemmOY CAT
Topans
TV
19 is a casing that extends across the back of the boiler, it is so arranged as to
receive air under pressure forced by the fan 6 through the pipe 34 connecting the
casing 19 with the front casing 4 (see Figs. 3 and 4). Fitted to the mouth of the
pipe 34 is an adjustable scoop or deflecting plate 85 by which the quantity and
pressure of air supplied to the casing 19 may be regulated. The casing 19 supplies
air under pressure into the pipes 20 which may be so placed in the back of the boiler
as to serve the purpose of and in lieu of an ordinary screw stay or stays. The
pipes 20 are screwed into the boiler plates and secured with screwed nuts or beaded
over in the usual manner. The air on passing through the pipes 20 enters a
chamber 21 perforated with holes or passages 22 which may conveniently he of
circular or oval form. This chamber is made of any suitable refractory material and
is situated in the combustion chamber 23 of the boiler in such a position that the air
passing through the passages 22 will be delivered in streams or jets upon and will be
caused to combine with gases evolved from the fuel. In connection with the pipes 20
butterfly" or ordinary throttle" valves 24 are provided, so arranged as to regulate
or cut off the supply of air through these pipes to the gases.
66
Instead of supplying air under pressure from the casing 19 into the pipes 20, a steam
jet may be arranged to induce a current of air into the pipe 20.
Doors 25 are provided to the mouths of the ash-pits to allow access thereto.
26, 26, 26, are sliding doors in the casings 4 and 19, by opening which various
testing instruments may be introduced as required.
The arrangement of apparatus provided ai the ends, of the ash-pits, and which is
shown separately in elevation sections and plan in Figs. 7 to 10, is as follows:-27 is a
vertical plate which is located close against the "blinder plate" 28 (see Fig. 3) and
is perforated with holes for the admission of air. 29 is a slide fitted in front of the
plate 27 this slide is perforated, and the arrangement is such that when in place, one
way up, its holes coincide with those in the plate 27 (see Fig. 8) but if the slide 29 ba
taken out, reversed, and replaced, it will then close the holes in plate 27 as shown in
Fig. 9. 30 is a lug by which to pull the apparatus out of its place to admit of
cleaning behind the bridge, and to facilitate the regulating of the admission of air by
alteration of the slide as described, or a tapped bolt 36 (see Fig. 10) may be used for
fastening the slide 29 in any intermediate position. 31, 31, are wing pieces for
guiding the apparatus as it is moved out of and returned into its place.
Referring to Figs. 5 and 6 which as before stated illustrate the application of
apparatus according to my invention to a double-ended boiler, 20, 20, 20, are air
pipes in the bottom and sides of the boiler, and 21, 21, 21, are the perforated air
chambers.
These chambers and the air pipes 20 are built into the usual centre bridge and thus
are surrounded and protected by the bricks and fire-clay of which the bridge is
composed. In Fig. 6 the combustion chamber 23 is shown in vertical cross section
in the line Z, Z, of Fig. 5 and the position of the air chambers 21 and of the air holes
or passages 22 in the said chambers, also the approximate positions of the pipes 20
when placed in the boiler sides. The air supply is regulated by a valve 24 located in
any suitable position within the air passages or pipes.
In other respects my apparatus as shown applied to this double ended boiler is
similar to that hereinbefore described with reference to Figs. 1 to 4.
In each arrangement the air is introduced into the combustion chamber 23 from the
chamber 21 practically in an opposite direction to that admitted through the ash-pit.
Referring to Figs. 11 and 12, 1 is the shell of an ordinary type of marine boiler
known as a
donkey-boiler." 21 is a perforated chamber into which a current of air
is induced through the pipe 24 by a jet of steam from the nozzle 32 of the steam
pipe 33. There may be several pipes and chambers provided to each boiler as
represented in Fig. 12; they may be so situated, and the holes or passages 22 in the
chamber 21 may be so arranged as to direct jets or currents of air practically all over
the fire-grate.

page_text: Although I have illustrated my invention as applied to furnaces of marine boilers, it
will be evident it may be adapted to furnaces of boilers of other types, and that the
details of construction may be modified to meet the requirements of particular
applications.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed, I declare that I do not claim
broadly introducing air into a closed ash-pit, or into a combustion chamber in rear of
a furnace, nor do I claim in connection with an under-grate blast the application of
an air inlet that can be closed before the fire door is opened, but what I do
claim is :-
In a marine boiler or other furnace or apparatus for effecting combustion of fuel
with air under pressure-
1. The combination and arrangement described and shown for reducing or cutting
off the air supply to an ash-pit below a fire-grate before the furnace door can be
opened, and increasing the supply or re-admitting air on fastening the furnace door
after it has been closed.
2. The arrangement with reversible perforated slide substantially as described for
admitting or cutting off the supply of air under pressure from the ash-pit to the space
or chamber rearward of the bridge to mix with gases evolved from fuel burnt on the
fire-grate as above set forth.
3. The combination and arrangement of parts for introducing air to the combustion
chamber comprising a pipe forming a stay to the inner and outer shells, a valve and a
perforated air chamber, substantially as described and illustrated.
4. Providing for admission of air under pressure in opposite directions respectively
through the ash-pit and through an independent perforated chamber located in the
combustion chamber in rear of the furnace, substantially in the manner described and
illustrated.
5. The combination and general arrangement of apparatus shown in and described
with reference to Figs. 1, 2, 3, 4, 7, 8, 9, and 10, of the drawings.
6. The modified general arrangement of apparatus as applied to a double ended
boiler as described with reference to and represented in Figs. 5 and 6 of the drawings.
7. In apparatus of the kind referred to for effecting combustion of fuel with air
under pressure, the use of fire-grates such as described with reference to the
drawings.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.