Improvements in and relating to Steam Boiler and other Furnaces.
Year: 1890

page_text: Date of Application, 18th Dec., 1890
Complete Specification Left, 16th Sept., 1891-Accepted, 21st Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in and relating to Steam Boiler and other Furnaces.
1, JAMES MUNRO, of Tillanburn, Holytown, Lanarkshire, Engineer, do hereby
declare the nature of my invention to be as follows:-
This invention has reference to and comprises certain improvements in the
construction and fittings connected with steam boiler furnaces and other furnaces,
for the supplying, heating, and combustion of the fuel, which may be coal, shale
wood, or crude waste oils, tars or other hydrocarbons or a mixture of these; and of
the supplying and heating of the air therefor, for the purpose of getting more
perfect combustion of the gases and fuel without the production or escape of smoke
from the furnace.
The nature and novelty of the improvements according to one arrangement
suitable for the fuel being burned in a furnace in the brickwork below a cylin
drical steam boiler, consist in forming within the brickwork near the front end of
the boiler a deep well furnace chamber or chambers preferably rectangular some-
what of the shape of a locomotive firebox with a lining of firebrick into which
the fuel is fed and burned, with an open end at top for the flame and gaseous
products of combustion to be ignited and burned under the front end of the boiler.
The lower end of this firebox or well furnace would have angled firebars lying
at perhaps about an angle of 45 degrees or less over the ashpit, the lower back
ends of the bars resting on a transverse supporting bearer, and also the front higher
ends resting on a bearer nearly close up to the front supporting wall of the furnace
and brickwork. Round the outer four sides of this firebrick furnace an air heating
aperture or jacket space preferably of from four to six inches would be left
between it and the outer walls of the furnace, with bricks projecting across at
intervals to support the inner furnace wall, and with horizontal partitions of one
brick thick or so at suitable distances vertically apart projecting from the outer
wall to within an inch or so of the inner wall. The projecting bricks inside of
furnace serve to support the weight of fuel thereby giving freer access to the air
getting through it. For some kinds of fuel the walls might be made plain or might
be constructed of metal or fire clay tube of uniform thickness and corrugated.
The air would be admitted to the lower end of this jacketed space by a special flue
entrance from the outer brickwork, or from the ashpit or both, and might also be
previously heated by the waste gases, and controlled by an air inlet valve to
regulate the quantity of air admitted or forced through this space to the upper part
of the furnace, and the air admitted or forced into the ashpit or under part
of the furnace may also be regulated by a valve. And these horizontal partitions
would baffle and retard the air ascending in this heating air space, and cause it to
pass up close to the inner furnace wall in thin layers past each partition, and so be
highly heated before it reached the top of this chamber. Or instead of these
horizontal baffling partitions, the air might be allowed to pass up through one or
more spiral channels or pipes formed in or round the outside of the inner furnace
casing, and so be heated in like manner before reaching the top, where in either
case the air inlet would be contracted and made to impinge in jets through broad
thin recesses over the top of the fire box all round, so as to inflame and burn all
the gases as they rose off the fuel at the top of the deep furnace. The fuel would
be fed in through a metal or equivalent strong channel fitted in the front wall at
the top of this furnace. This channel might either be made horizontal or at an
angle downwards to facilitate the feeding of the fuel from a hopper fitted over the
front end of this channel hearth, outside the front brickwork of the building; and

page_text: the fuel might either be fed through this feeding channel by an intermittent
reciprocating plunger or plungers or in a constant slow stream by screws or other
equivalent feeders, and would burn the hydrocarbon gases off the fresh fuel as it
was fed in over the top of the incandescent fuel burning in the furnace below it
down the whole depth of the furnace, as the fire would be kindled on the lower
bars, and air would be admitted through them from the ashpit below, to maintain
combustion of the fuel from the furnace bars upwards, and so have a great heat at
the top to completely burn the hydrocarbon gases as formed where the air would
meet them at the top of the furnace under the front end of the boiler. And where
waste liquid hydrocarbons or tars from the distillation and refining of mineral oils
are plentiful these may be fed in in spray or other jets over the top of this furnace,
and be burned with the coal or other solid carbon fuel, and the gases evolved
burned there by the jets of highly heated air from the air heating chamber round
the furnace.
In some cases compressed air may be used for producing a draught in the
furnaces, and a-steam or superheated steam jet may also be used to combine with
the air to produce combustion. When this furnace is applied to Cornish or Lanca-
shire large internal flue boilers, the gases and flames so burned in this new manner
in this deep furnace at the front end of the boiler, might either be carried along
through the flues in the brickwork to heat the under surface and sides of the boiler
and return through the flues, or enter through the flues and return along the under
surface and sides of the boiler.
In applying these improvements to locomotive and semi-portable tubular boilers,
and other boilers where it was not possible to get the "well" shaped furnaces
deeper than they are at present, the furnace bars may be put at a less angle and
made movable to carry off the ashes and clinkers behind, and admit the air to keep
-the furnace-fuel-over-them-always-in an incandescent state to maintain the gases
above at an inflammable heat; and the air for these shorter furnaces may be heated
through coiled or undulated pipes fitted in the horizontal or flame flues of the
boiler or otherwise, and forced through these heating tubes by fans or other-forced-
blast to meet the gases in a highly heated state rising off the fuel at the top of the
"well" furnace, instead of being wholly heated in the casing round this furnace as
before described. For marine large furnace flue and return tubular boilers, these
"well" furnaces and fuel feeding arrangements might be either fitted in front of
the end of the boiler, or the lower part of the boiler below the side or higher flues
of three-flue boilers, by cutting away the ends of the boilers below these flues so-as
to get a deep vertical furnace with slightly angled or movable grate bars below,
with automatic stoking mechanism above feeding in the fuel at the top part of
these side flues and deep furnaces heating the air round their upper parts and-in
tubes in the flame flue while forcing it through to meet the gases from the green or
fresh fuel at the upper part of the furnace; and the flames from these two side
furnaces might return through the lower large central flue as well as the upper
return tubes without a furnace in it, but with cross water circulating tubes. And
in some cases where reciprocating or movable furnace bars or traversing bars of
the chain character were not used for removing the ashes and clinkers, the bars
might be fitted so as to oscillate down at the back or in front of the ashpit to
clean the furnace or discharge the incandescent fuel at night or when work was
over. In some cases fire bars may be dispensed with and a fire brick hearth used
either with or without perforations up through it as when using-compressed-air_to_
produce a draught, and closing up the ashpit. These improvements are also
applicable to furnaces for other purposes than steam boilers such as kilns or gas
producers, in which case the flues would be modified for the passage of the heated
products of combustion from the furnace and the air heated by the flues might be
led in at the lower part of the furnace when the ashpit was closed and have only
part of it led into the top of the furnace to consume the gases; or the heated air
may be kept quite separate from the gases, and be led through a regenerator and

page_text: nly allowed to combine in the furnace where their inflammable combustion was
desired to be utilized as in ordinary regenerative furnaces. And in this way the
furnace would be more of the nature of a gas producing furnace, and have the
fuel fed intermittently or otherwise into a close chamber at the top of the "well"
furnace and might have the hydrocarbon gases drawn off from the bottom of the
furnace through flues to the regenerators, sufficient air being allowed to enter at
the top or bottom of the furnace only to consume the coals or fuel to produce the
gases led off as stated from the regenerator to meet the heated air from its heating
flues and regenerator where the gases combined and are to be burned and
utilized.
בד
71
1000
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.
COMPLETE SPECIFICATION.
Improvements in and relating to. Steam Boiler and other Furnaces.
I, JAMES MUNRO, of Tillanburn, Holytown, Lanarkshire, Engineer, do hereby
declare the nature of my invention, and in what manner the same is to be performed
to be particularly described and ascertained in and by the following statement in
writing reference being had to the accompanying two sheets of drawings, and to the
letters and figures marked thereon, that is to say :-
My invention has reference to and comprises certain improvements in the
construction and fittings of and connected with steam boiler furnaces,. and other
furnaces, for the supplying heating and combustion of the fuel, which may be coal,
shale, wood, or crude waste oils, tars, or other hydrocarbons or a mixture of these;
and of the supplying and heating of the air therefor, all for the purpose of getting
more perfect combustion of the fuel and of the gases produced therefrom, without
the production in or escape of smoke from the furnaces fitted with these
improvements.
And in order that my said invention and the manner of performing or carrying
the same into effect or practice may be properly understood, I have hereunto
appended two sheets of explanatory drawings in which the saine reference
letters are used to indicate corresponding or like parts in all the figures where
shown.
Figures 1 and 2 on Sheets 1 and 2 are respectively longitudinal vertical and
horizontal sections, the latter taken on the lines 1-1 in the former, both of one
general construction of my improved furnace and fittings, or arrangement and
combination of the parts of my improvements or invention as formed and fitted in
the brickwork A, under and around a single horizontal cylindrical steam boiler B,
with domed ends, but having a part of the length broken away at Z, Z; and
intended for the burning of ordinary broken up coal as fuel, but it might also be
used for shale or wood fuel, or a mixture of any or all of these.
Figure 3 Sheet 3 is a transverse vertical section as taken on the line 2-2
through the furnace A', in Figure 1, and
Figure 4 is a front end elevation, both of and corresponding to Figures 1 and 2;
while
Figure 5 Sheet 2 is a sectional side elevation as taken on the line 3-3 in
Figure 2 through one of the air heating side flues C of the furnace A'.
Figure 6 on Sheet 4 is a sectional side elevation of the front end part of a
horizontal cylindrical steam boiler B, with a single internal cylindrical flue B', and
transverse Galloway tubes B", shown as having the back end broken away at Z, Z,
as fitted with one arrangement and combination of the parts of my improved
furnace and fittings as applied within the front end of said flue B', for this class of
boilers.

page_text: Figure 7 is a sectional end elevation as taken on the line 1-1 through the
furnace A in Figure 6, looking from the front end.
Figure 8 is a sectional end elevation taken on the line 2-2 in Figure 6, looking
from the back end.
Figure 9 is a sectional elevation of the deep front end furnace part A¹ of a
multiple flue tubular steam boiler of the locomotive or semi-portable class, shown
as fitted with one arrangement and combination of the parts of my improvements
illustrative of the application of these to this class of boilers, the back part of the
boiler and tubes being broken away at Z, Z.
Referring to the arrangement and combination of my improvements as shown in
Figures 1 to 5 on Sheets 1 to 3 inclusive of the drawings;-The nature and novelty
of the improvements as applied to this class of steam boiler and furnaces consist in
forming within the brickwork A, near and under the front end B of the boiler B,
a deep well furnace chamber A', (or it might be chambers) preferably rectangular
somewhat of the shape of a locomotive firebox-with-an internal lining of firebrick
at the sides and ends a, a, into which the fuel is fed and burned, with an open end
or part A, A, at the top for the flame and gaseous products of combustion to be
ignited and burned under the front end of the boiler B. The lower end or bottom
of this firebox or well furnace A would preferably have angled fire bars A, lying
at a considerable angle downwards and backwards over the ashpit A³, below the
bars the lower back ends of the bars A resting on transverse supporting
bearers A, and also the front higher ends resting on a bearer nearly close up to
the front supporting wall of the furnace and doorplate A', at the front end of the
brickwork. Or instead of firebars perforated firebrick may be used as shown in
Figures 6 and 7 on Sheet 4. Round the two sides a, a, and back ends a' of this
firebrick furnace A', close deep air hesting or jacketted spaces C, C, and C¹,
-preferably of from four to six inches wide-would be formed between the inner
walls a, a', and the outer wall A, A, of the brickwork with cross bricks all
projecting across at intervals to support the inner furnace walls a, a', and covered in
at top-with slabs-as-seen particularly in Figure-3-Sheet 3, and with horizontāl
partitions of plates a² at suitable distances, vertically apart prejecting from the
outer walls A, A, to within an inch or so of the inner walls a, a, where projecting
bricks are placed alternating with the plates a². The bricks-a, may be made
to project inside of furnace to assist in supporting the weight of fuel, thereby
giving freer access to the air getting up through it at the sides. A part of these
vertical heating side-chambers C, C, is made to extend across the fourth or front
side of the furnace at C", as seen particularly in Figure 1. All these vertical air
heating chambers C to C", have apertures c at top under the cover plates a³,
extending through the inner walls a, a, into the furnace A', for the entrance of the
heated air in thin jets into the furnace, to meet the gases rising off the fuel. The
air is admitted to these heating chambers C, to C", round the furnace A¹, at
the lower back end C2, by special longitudinal flues or pipes C³, at each side of the
back flue B², under the boiler shown dotted in in Figures 1 and 2 and each fitted
with a regulating valve at C², actuated by a long rod handle C, from the cleaning
doors C, in the front end of the brickwork. The air admitted to these
pipes C³, C³, would preferably be previously heated by the waste gases passing off
from the back end of the flue 132 under the boiler through a chamber B³ leading to
the chimney flue 131, controlled by the damper Bias seen particularly in
Figures 1 and 2, or the damper may be fitted at the back end of the boiler B, and
its flue B2, just before entering the air heating chamber 133, the chamber B³ being
fitted with a set of horizontal air heating tubes b, fitted with internal alternating
baffle plates or discs b', with their one side cut away and connected by central
rods b, for drawing them out and cleaning the tubes b, the air from the atmosphere
passing and undulating through from one end of these tubes into a vertical
chamber B, at the other end and be led into the pipes C³, by a cross channel at C.
Although these sets of tubes have been shown as arranged horizontally in the

page_text: heating chamber B°, they might be arranged vertically or at any angle between
the horizontal and vertical. And further, the air (for these short deep furnaces A¹
with air heating jackets C, C, C", round them) may in some cases be passed
through horizontal or vertical heating or coiled or undulated pipes, and in either
case be fitted in the flame, or waste gas flues leading from the furnace to the
chimney, and the air to be heated in these tubes would or might be forced through
them by fans or other air blowers used for forced blast, to meet the gases in a
highly heated state rising off the fuel at the top of this deep furnace, instead of
being wholly heated in the casings C, C₁, C", round it, as before described. The
fuel F, is here shown as fed in to the furnace A', over the fire bars A up nearly
to the top by hand or otherwise through a metal or equivalent strong charging
channel or mouthpiece F, fitted with ordinary closing doors F", in the front end
wall A of the brickwork at the top of the furnace A. This charging channel or
doorway F might either be made horizontal or fitted at an angle downwards, as
shown in Figure 1, to facilitate the feeding in of the fuel; or it might be for being
fed from a hopper, when that was desired, fitted over the front end of this channel
hearth, outside the front brick-work A, or furnace A', without doors F", as
indicated more particularly in the arrangements Figures 6 and 9 of the drawings.
Air would be admitted or forced into the ashpit A³, and pass up through the
furnace bars A, and be regulated by the closing door A' in the front end plate A,
to maintain the proper combustion of the fuel over and in front of the furnace
bars Aupwards, so as to have the greatest heat at the top of the furnace A' to
completely burn the hydrocarbon gases as they are there evolved from the fuel,
and where the heated air would meet them issuing from the openings 6, at the
top A, of the furnace A', under the front end B of the boiler B. A door A³,
is fitted in the plate A', and outer end of bars A, for getting in a poker or other
equivalent for stirring up the fuel over the bars, and also for drawing the bars A,
forward on their cross supporting bars A, when that is desired to allow the ashes
or clinkers to fall down into the ashpit A3 from which they could be removed
through the door A. At this end B of the boiler B at the front of the charging
door of the fuel F, a drooping or hanging hollow air heating arch F is formed,
the ends of this hollow arch leading in at F3 into the top of the air heating
chambers C, C, to receive air, which is projected down and forward into the top of
the furnace A', through slits el to impinge in jets down on the gases rising off the
fuel, as shown more particularly in Figures 1 and 2, and indicated by the darts in
these figures. It will be seen that the horizontal partitions a², a, baffle, and
retard the air ascending in the heating air spaces C, C, and C, C, and cause it to
pass close up to the inner hot furnace walls a, a, a', a', and undulate in thin layers
past each partition a, a, and so be highly heated before it reached the top of
these chambers C, C₁, where it would be passed through the contracted
apertures c, c, and made to impinge in broad thin jets over the top of the fire
box a, a, a, all round, so as to burn all the inflammable gases as they rose off the
fuel F, at the top of the deep furnace A, all as indicated by the darts in Figures 1
to 3. These air jet apertures c are fitted with side and end perforated or equivalent
plates, with handles c³, passing out through the front end of the furnace wall,
as shown more particularly in Figure 5 so as to regulate the admission of hot air to
the furnace through these apertures_c. Although have only shown one row of
these apertures c, under the fireclay slabs u³, covering in the air heating
chambers C, C, C", near the top of the furnace A', it will be understood that one,
two, or more rows of these apertures may be formed further down through the
walls a, a, of the furnace A
The flames and heated gases formed at the top A" of this furnace A', are led off
through lateral flue openings A2, close in front of the bridge F, and pass off
through longitudinal continuations of these flues A², over the top a³ of the side
heating chambers C, and sides of the front end of the boiler, into the long heating
flue chambers B2, under the back end of the boiler, and caused to undulate pre-
ferably alternately through openings in or round the ends of transverse brick

page_text: partitions B, all as shown and indicated by the arrows in Figures 1, 2 and 3.
Instead of having the horizontal baffling partitions a, a, as described, in the air
heating chambers C, C', C", the air might be made to pass up through and round
one or more spiral channels formed in these heating spaces C, C, C", or pipes or
flues fitted in or round the outside of the inner furnace casing a, a', and so be highly
heated before reaching the top, as before described. Where waste liquid hydro-
carbon oils or tars from the distillation and refining of mineral oils are plentiful
these may be fed in spray or other jets over the top of these furnaces A, and be
burned with the coal or other solid carbon fuel F, and the gases evolved be completely
burned there by the jets of highly heated air from the air heating chambers C,
C, C, round the furnace A'. One arrangement of effecting this is shown dotted
in in Figure 3, where a jet nozzle D leads the liquid oils or hydrocarbons into a
close air-jet nozzle D', fitted over the top slabs a³, of the heating chambers C, or it
might be through the chamber C, so that the jet of oil forced in through the
nozzles D, D', would also force and draw in heated air from the upper part of the
chamber C, and force both jets of oil and air down into the furnace A'; and any
number of these jets may be arranged in this way over or through the sides of the
furnace A When forced draught is used to force the air into the heating tubes b
and chambers C, C, this air acting in the outer close annular nozzle D', round the
oil nozzle D, would assist in drawing the oil through the nozzle D and spraying it
into the furnace.
When this improved furnace and fittings are to be applied to Cornish, Lancashire,
or other large internal flue boilers with one or two flues, the gases and flames
produced and burned as described, in this new or improved deep air heating furnace A¹
at the front end of the boiler, might first be carried along through the flues A², B²,
in the brickwork.A.to.beat the_under surface_and_sides_of_said boiler, and then
made to return through the internal flue or flues to the chimney flue; or otherwise
be first entered and passed through the internal flues, and returned back along the
under surface and sides of the boiler-before-admission to the chimney flue. Or
otherwise as shown in Figures 6 to 8 on Sheet 4 of the drawings, this new or
improved furnace A' may be fitted within the front end of the internal flue B
of such boilers; and referring to these figures, the bottom of the furnace A', would
be formed with perforated blocks of fireclay A, in preference to fire-grate bars,
as shown in Sheet 1, and supported on low arched bars A, and have the air
passed or forced into the ashpit A3, from the chamber C₁ through the openings
and regulating valve E, E, to pass up through the perforations in the firebrick
blocks. In this arrangement the sides a of the furnace A are formed of corrugated
blocks, and have the baffle plates a², fitted on segmental plates within the side
recesses C, C, of the furnace part of the flue B', so that the air which in this case
enters through a single pipe flue C³, fitted in the centre of the back flue B¹
under the Galloway tubes 6" passes forward and enters a cross flue C² which
leads the air to the sides and end heating chambers C, C', C", where it is heated
by undulating up between the baffle plates a² and the corrugations or bricks a
of the inner sides a, a', of the furnace A, so as to pass in by the openings c, in
thin layers under the top closing plates a. The gases and flames in this case pass
off from the top of the furnace A at A2; over the arch space A", and the furnace
in this case is fitted with a broad funnel shaped charging hopper F¹ for filling in
the fuel behind the back of the hollow arched bridge F2; otherwise the deep
furnace A', and its fittings are substantially the same and lettered to correspond
with that described in reference to Sheet 12 and 3 of the accompanying drawings,
the darts indicating the admission of air, and the arrows the currents of the flames
and hot gases through the furnace and flues.
In applying these improvements to locomotive and semi-portable tubular flue
steam boilers, and other boilers where it is scarcely possible to get applied the deep
shaped furnaces A', with the fuel and feeding arrangements above outside, and
the angled furnace bars below, the furnace bars A may be fitted at a less angle
or horizontally, or be made movable to carry off the ashes and clinkers behind,

page_text: and also admit the air to keep the furnace fuel over them always m an
incandescent state to maintain the gases above at an inflammable heat. Referring
to Figure 9 on Sheet 4 of the drawings, this shows an application of my improve-
ments to a locomotive or semi-portable boiler B with ordinary rectangular fire-
box and set of small flue tubes d, in which an improved deep furnace A is formed
by four inner corrugated side and end plates a a' carried on a lower ring A
and brackets d projecting some few inches from the inner sides of the lower part of
the ordinary firebox d', above the firebars A, to form the air heating jacketed
chambers C, C, C", with baffle plates a fitted within the corrugations in these
heating chambers, which are covered all round with fireclay bricks or slabs a³ on
top some distance below the flue tubes d. The fire bars A are carried on the
ring A, secured to the lower end of the ordinary firebox d', by brackets (2
leaving openings within the ring and beyond the ends of the firebars to allow the
air to pass up and be heated within the jacketed spaces C, to C", undulating
between the corrugations of the side walls a, à', and the baffle plates a, until they
reach the top of these heating spaces, where they pass in through the slots ce
into the top part of this deep air heating furnace A, to meet the gases rising
off the fuel F. The fuel in this case is shown as fed in through a hopper shaped
funnel F and hollow air heating nozzle F3, with an annular air heating space,
round its lower part into which the air passes at ' from the upper part of the
front heating chamber C and passes out in small thin jets at c at the lower end
of the fuel feeding nozzle F³ so as to meet the gases rising off the fuel and
inflame them as they pass up to and through the flame tubes d, all otherwise
substantially as described in reference to the former figures and indicated by the
darts and arrows in this figure. For the purpose of seeing that the gases are
being properly burned as they pass off from the top A of the furnace A', a duct
and closing doorway F, F, is formed through the front brickwork in line with
the side flues A2, and which will also carry away the gases from behind the
bridge and have openings ², controlled by valves passing up through the top
covers for heated air jets to burn the gases in these channels F, A², as shown
particularly in Figures 1 to 4. In some cases the fuel might be fed through the
charging channels or hoppers F', by an intermittent reciprocating pushing plunger
or plungers, or otherwise this may be done in a constant slow stream by a screw
or other equivalent feeder fitted in these hoppers F', so as to burn the hydro-
carbon gases off the fresh fuel as it was fed in over the top of the incandescent
fuel previously fed in and burning in the furnace below and in front of it down
the whole or the greater depth of the furnace A', as the fire would generally be
kindled on the lower bars A, in all these arrangements.
In applying these improvements to marine large furnace flue steam boilers,
with sets of small return flue tubes, these deep or "well" furnaces A', with air
heating casings C, C, C", round them and fuel feeding arrangements above might
be either fitted in front of the end of the boiler, or in the end of the flues them-
selves, as shown in Figures 6 and 7 on Sheet 4; or at the lower front end part, as
below the two higher side flues of three flue boilers, by cutting away the front end
parts below these flues so as to get a deep vertical furnace with slightly angled or
movable grate bars below each with automatic stoking mechanism above in front
for feeding in the fuel by hoppers F at the top part of these side flues with deep
furnaces and jackets round them for heating the air, and either with or without
the tubes in the flues leading to the chimney while forcing it. through to meet the
gases from the green or fresh fuel in thin jets at the upper part of the furnace A',-
as indicated in Figures 6 and 9, while the flames from these two side furnaces,
might be made to return through the lower large central flue without a furnace in
it but in which the sets of tubes might be fitted for heating the air for the other
two furnaces, as well as return through all the upper ordinary tubes to the smoke
box. And in some cases where reciprocating or movable furnace bars or traversing
bars of the chain character were not used for removing the ashes and clinkers, the
bars might be fitted so as to oscillate down at the back or in front of the ashpit to

page_text: clean the furnace or discharge the incandescent fuel at night or when work was
over. These examples will show to practical engineers how my improved deep
furnace with air heating casing round it, is also applicable to marine boilers with
corrugated or other large furnace flues.
Although in the foregoing drawings and description of these improved deep
furnaces have mainly shown and described cold air as admitted to the ashpit A³,
below the furnace bars for supporting the combustion of the fuel over them it is
to be understood that heated air may be admitted thereto from the surrounding
heating chambers C to.C" controlled also by an admission valve as indicated
at E, E', in Figures 1 to 6; and that although I have only shown and described
these furnaces as formed of a rectangular shape in horizontal section with the
surrounding air spaces also rectangular, it is to be understood that they may be of
round, oval, or other shape with the air heating spaces surrounding them of like
shape to suit the shape of the steam boiler or other heating furnace or purpose to
which they were to be applied.
These improved furnaces A', and fittings, especially as shown on Sheet 1, are also
applicable to vertical boilers which might be erected on the brickwork, either over
the furnace chamber A1, especially for internal flue_vertical boilers when the flames
and gases would pass up through the central flue to the chimney with heating
cross tubes above in the flue, or at some distance behind it when applied to vertical
boilers without flues, so that the flames and heated products of combustion would
be conveyed away back in flues in the brickwork to heat the lower end and sides
of the boiler before being led to the chimney. Or these furnaces may be applied.
to smelting or reheating plate or bar furnaces by conveying the flames and heated
products to the smelting and heating chambers of these furnaces. These improve-
mments are also applicable-to-furnaces for other purposes such as kilns or gas
producers, in which case the flues would be modified for the passage of the heated
products of combustion from the furnace, and the air heated by the flues might
be_led_in_at_the_lower part of the furnace when the ashpit was closed and have
only part of it led into the top of the furnace to consume the gases.; or the heated
air may be kept quite separate from the gases and be led through a regenerator
and only allowed to combine in the furnace where their inflammable combustion
was desired to be utilized as in ordinary regenerative furnaces. And in this way
the furnace would-be more of the nature of a gas producing furnace, and have the
fuel fed intermittently or otherwise into a close chamber at the top of the "well"
furnace and might have the hydrocarbon gases drawn off from the bottom of the
furnace through flues to the regenerators, sufficient air being allowed to enter at
the top or bottom of the furnace only to consume the coals or fuel to produce
the gases led off as stated from the regenerator to meet the heated air from
its heating flues and regenerator where the gases combined and are to be burned
and utilized.
Having now particularly described and ascertained the nature and novelty of my
invention and the mode of performing and putting it into practice I would have it.
understood that I do not confine myself to the precise combinations of the parts of
furnaces which I have had occasion to delineate and describe, such as the various
ways of heating the air for such furnaces before reaching the heating chamber
-surrounding-the-furnace, neither do-l-confine myself-to-natural-or forced-draught-of-
the air to and through said furnaces, or to close or open ashpits, but what
I consider to be novel and original and therefore claim as the invention secured to
me is :-
First. The construction or arrangement and combination of the parts of steam
boiler and other furnaces with deep or "well" furnace chamber or chambers and
air heating casings or spaces surrounding said furnaces, substantially as herein
described in reference to and by way of application shown in the accompanying
drawings.
Second. The arrangement and combination of the parts of deep furnaces with

page_text: combustion and air heating chambers, ducts, and fittings, built in the brickwork,
substantially as and for the purposes herein described in reference to and shown on
Sheet 12 and 3 of the accompanying drawings.
Third. The arrangement and combination of the parts of deep furnaces with air
heating chambers and fittings, in the flues or fire-box, substantially as and for the
purposes herein described in reference to and shown on Sheet 2 of the accompanying
drawings.
.
Fourth. In steam boiler and other furnaces the construction and use of air
heating chambers or jacketed spaces or flues surrounding said furnaces, substantially
as and for the purposes herein described in reference to and by way of application
shown in the accompanying drawings.
Fifth. In steam boiler and other furnaces the arrangement and use of air heating
chambers or jacketed spaces surrounding said furnaces, with baffle deflecting plates
or slabs or corrugated or fluted surfaces for undulating and heating the air, and with
ports for admitting the heated air in thin jets to the furnace, substantially as and
for the purposes herein described in reference to and by way of application shown
in the accompanying drawings.
Dated the 15th September 1891
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.