Improvements in Stoves or Apparatus for Heating Air.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Improvements in Stoves or Apparatus for Heating Air.
I, SAMUEL CLELAND DAVIDSON of Sirocco Engineering Works, Belfast,
Ireland, Merchant, do hereby declare the nature of this invention to be as
follows:-
This invention has reference to stoves or apparatus for heating air and, its objects
are to obtain a maximum volume of heated air in proportion to the amount of fuel
consumed in the furnace of the stove and at the same time to have those parts of
the furnace or fireplace which are in the immediate proximity of the fire capable
of withstanding its corrosive or smelting effects for a long period; also to have
other parts which are further away from the fire shielded from direct radiant heat
therefrom and so constructed that in the event of the tubes or pipes therein
employed also becoming burnt or worn out they can easily be replaced by new
ones without its being necessary to take down any considerable part of the stove
for this purpose.
The invention chiefly consists in the combination in a stove or apparatus for
heating air, of a central furuace constructed as a gill stove, one or more smoke
chambers at the back of the said furnace and in communication therewith, a set of
flow tubes or pipes parallel with the sides of the furnace, one or more front smoke
chambers between which and the said back smoke chambers the said tubes or pipes
communicate so as to conduct the products of combustion from the back chambers
to the front chambers, a second or return set of tubes or pipes below and parallel
with the flow set and leading from the front smoke chambers, a back flue or chamber
into which the said second set of tubes lead, the said back flue or chamber being
in communication with the chimney, and an air inlet or air inlets at the lower part
of the stove to admit the air to be heated at such a part that it comes into contact
with the lower or return set of tubes before passing over the upper and more
highly heated set.
The invention comprises an arrangement as hereinafter described for securing
the tubes or pipes in the walls or sides of the smoke chambers.
"
In carrying out the invention the improved stove or apparatus is constructed
with the furnace or fireplace in the centre of the stove, and with a number of
narrow and relatively deep bars of (preferably) cast-iron, bolted to one another so.
as to form continuously solid enclosing sides and top for the furnace from front to
back, with gills cast on their outer edges similar to the ordinary (so called) "Gill "
stove, and the interior sides of the furnace are also fitted with what I term "false
sides consisting of cast-iron plates or tiles, suitably constructed for admitting air.
from the ashpit to above the surface of the fire, in order to complete the combustion
of the gases arising therefrom; an opening is provided at the back of the fireplace
for escape of the products of combustion into smoke chambers which lead to right
and left therefrom, and in each of these smoke chambers, on the side or wall
facing the front of the stove, there are perforations into which are inserted iron
tubes or pipes which are arranged as a group, on each side of and parallel to the
furnace, at preferably above the level of the fire, to conduct the products of
combustion to other and similar smoke chambers on right and left of the front
door of the furnace. These smoke chambers extend downwards to preferably the
floor-level of the ashpit and the products of combustion on being delivered into

page_text: the upper part of these front chambers descend and return again through a lower
set or group of pipes to the lower part of the back smoke chambers, separated
from the upper part by a dividing plate, and from which lower compartment they
pass into the chimney, which is placed preferably at a slight distance from and
immediately behind the back of the furnace.
The pipes which convey the products of combustion to and from the front and
back smoke chambers fit somewhat loosely into the above mentioned perforations
in the sides of the smoke chambers, so that they are capable of sliding freely
through same when being put into position, and their ends project slightly through
the perforated plates of the smoke chambers, and each end fits into a groove or
glandular recess in an annular shaped movable cap or encasing cover constructed
with lugs, formed as inclined planes, so that when the caps are turned round upon
the projecting ends of the pipes, they engage into catches or recesses in projecting
snugs which are fitted on the corresponding face of the perforated side plates of
the smoke chambers, and which thus hold the caps firmly in position; and in order
to make their joints smoke tight, the grooves or glands in the caps are lined with
asbestos or any suitable cement in which the pipe ends are embedded. If any of
these pipes require replacement, from becoming in course of time corroded or
burnt through, it is only necessary to turn back the caps so as to free their lugs
from the above described catches or snugs at either end, whereupon the pipe can
be easily withdrawn and a new one inserted and secured in its place.
The sides of the smoke chambers facing the perforated sides containing the ends
of the pipes, are provided with suitable cleaning doors for brushing out the pipes
and removal of soot, and through which the pipes can be withdrawn when being
changed. The whole stove is enclosed in a sheet metal casing, with the top
preferably pyramid or cone shaped, to converge the heated air as it rises from
about the pipes and furnace into a tube or air duct, to convey it to wherever it
may be required, and doors are provided in the sides of the casing opposite the
cleaning doors in the smoke chambers to conveniently get at them.
• Some of the advantages of my improved stove, in addition to the durable con-
struction of the furnace and easy replacement (when such may be necessary) of
any of the tubes or pipes, are that the body and ends of the pipes, owing to their
relative situation in respect of the furnace, and to their not being in contact with
its sides, are not exposed to the direct radiant heat from the fire itself; and receive
almost no heat from it by conduction, so that they are practically therefore only
heated by the products of combustion passing through them, consequently it is
merely at their hottest ends (and then only under the exceptional circumstances
due to forced firing) that they attain a red heat sufficient to corrode or burn them
out; and as the hottest gases from the fire traverse the upper groups of the pipes
first, and then afterwards pass to the lower ones over which flows the first inrush
of cold air to be heated, the hot gases from the fire are thus very efficiently cooled
before passing to the chimney; further as the passages for the flow of the air to
be heated by the stove are very open and free amongst the pipes and over the
furnace gills, so that the air in passing amongst them encounters a minimum of
friction, and as the total area of effective heating surfaces for the air passing
through the stove is relatively very large in comparison to the size of the fire being
burnt therein the volume of air heated and amount of heat transmitted thereto
from the fire are both so great that they show very high results both for efficiency
and economy as regards the amount of fuel consumed.
Dated this 28th day of September 1895.
J. C. MEWBURN & ELLIS,
55 and 56 Chancery Lane, London, Chartered Patent Agents.

page_text: I, SAMUEL CLELAND DAVIDSON of Sirocco Engineering Works, Belfast,
Ireland, Merchant, 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:-
This invention has reference to stoves or apparatus for heating air and its objects
are to obtain a maximum volume of heated air in proportion to the amount of fuel
consumed in the furnace of the stove and at the same time to have those parts of
the furnace or fireplace which are in the immediate proximity of the fire capable
of withstanding its corrosive or smelting effects for a long period; also to have
other parts which are further away from the fire shielded from direct radiant heat
therefrom, and so constructed that in the event of the tubes or pipes therein
employed also becoming burnt or worn out they can easily be replaced by new
ones without its being necessary to take down any considerable part of the stove
for this purpose.
1
The invention chiefly consists in the combination in a stove or apparatus for
heating air, of a central furnace constructed as a gill stove, one or more smoke
chambers at the back of the said furnace and in cominunication therewith, a set of
flow tubes or pipes parallel with the sides of the furnace, one or more front smoke
chambers between which and the said back smoke chambers the said tubes or pipes
communicate so as to conduct the products of combustion from the back chambers
to the front chambers, a second or return set of tubes or pipes below and parallel
with the flow set and leading from the front smoke chambers, a back flue or chamber
into which the said second set of tubes lead, the said back flue or chamber being
in communication with the chimney, and an air inlet or air inlets at the lower part
of the stove to admit the air to be heated at such a part that it comes into contact
with the lower or return set of tubes before passing over the upper and more highly
heated set.
The invention comprises an arrangement as hereinafter described for securing
the tubes or pipes in the walls or sides of the smoke chambers.
'
In carrying out the invention the improved stove or apparatus is constructed
with the furnace or fire place in the centre of the stove, and with a number of
narrow and relatively deep bars of (preferably) cast iron, bolted to one another so
as to form continuously solid enclosing sides and top for the furnace from front
to back with gills cast on their outer edges similar to the ordinary (so called)
"Gill" stove, and the interior sides of the furnace. are also fitted with what I term
"false sides " consisting of cast iron plates or tiles suitably constructed for
admitting air from the ash-pit to above the surface of the fire, in order to
complete the combustion of the gases arising therefrom; an opening is provided at
the back of the fireplace for escape of the products of combustion into smoke
chambers which lead to right and left therefrom, and in each of these smoke
chambers on the side or wall facing the front of the stove there are perforations
into which are inserted iron tubes or pipes which are arranged as a group on each
side of and parallel to the furnace, at preferably above the level of the fire, to
conduct the products of combustion to other and similar smoke chambers on right
and left of the front door of the furuace. These smoke chambers extend downwards
to preferably the floor level of the ash-pit and the products of combustion on being
delivered into the upper part of these front chambers descend and return again
through a lower set or group of pipes to the lower part of the back smoke chambers,

page_text: separated from the upper part by a dividing plate, and from which lower compart-
ment they pass into the chimney which is placed preferably at a slight distance
from and immediately behind the back of the furnace.
The pipes which convey the products of combustion to and from the front and
back smoke chambers fit somewhat loosely into the above mentioned perforations
in the sides of the smoke chambers, so that they are capable of sliding freely
through same when being put into position, and their ends project slightly through
the perforated plates of the smoke chambers, and each end fits into a groove or
glandular recess in an annular shaped movable cap or encasing cover constructed
with lugs, formed as inclined planes, so that when the caps are turned round upon
the projecting ends of the pipes, they engage into catches or recesses in projecting
snugs which are fitted on the corresponding face of the perforated side plates of
the smoke chambers, and which thus hold the caps firmly in position; and in order
to make their joints smoke tight, the grooves or glands in the caps are lined with
asbestos or any suitable cement in which the pipe ends are embedded. If any of
these pipes require replacement from becoming in course of time corroded or burnt
through, it is only necessary to turn back the caps so as to free their lugs from the
above described catches or snugs at either end, whereupon the pipe can be easily
withdrawn and a new one inserted and secured in its place.
The sides of the smoke chambers facing the perforated sides containing the ends
of the pipes, are provided with suitable cleaning doors for brushing out the pipes
and removal of soot, and through which the pipes can be withdrawn when being
changed. The whole stove is enclosed in a sheet metal casing, with the top so
constructed as to converge the heated air as it rises from about the pipes and
furnace into a tube or air duct, to convey it to wherever it may be required, and
doors are provided in the sides of the casing opposite the cleaning doors in the
smoke chambers to conveniently get at them.
Some of the advantages of the improved stove, in addition to the durable con-
struction of the furnace and easy replacement (when such may be necessary) of
any of the tubes or pipes, are that the body and ends of the pipes owing to their
relative situation in respect of the furnace, and to their not being in contact with
its sides, are not exposed to the direct radiant heat from the fire itself; and receive
almost no heat from it by conduction, so that they are practically therefore only
heated by the products of combustion passing through them, consequently it is
merely at their hottest ends (and then only under the exceptional circumstances
due to forced firing) that they attain a red heat sufficient to corrode or burn them
out; and as the hottest gases from the fire traverse the upper groups of the pipes
first, and then afterwards pass to the lower ones over which flows the first inrush of
cold air to be heated, the hot gases from the fire are thus very efficiently cooled
before passing to the chimney; further as the passages for the flow of the air to
be heated by the stove are very open and free amongst the pipes and over the
furnace gills, so that the air in passing amongst them encounters a minimum of
friction, and as the total area of effective heating surfaces for the air passing
through the stove is relatively very large in comparison to the size of the fire being
burnt therein, the volume of air heated and the amount of heat transmitted thereto
from the fire are both so great that they show very high results both for efficiency
and economy as regards the amount of fuel consumed.
In the accompanying drawings,
Figure 1 is a front elevation of a stove constructed, according to this invention ;
Figure 2 is a cross section on line z z of Figure 4;
Figure 3 is a transverse section on line y y of Figure 4;
Figure 4 is a plan; and Figure 5 a sectional plan on line x of Figure 1.
Figures 6, 7 and 8 are detail views on a larger scale showing in elevation plan
and horizontal section respectively, the arrangement for securing the tubes or pipes
in the walls or sides of the smoke chambers.
A is the fireplace, B B are the metal ribs forming and enclosing same, with

page_text: "gills" or ribs & on their outer side supported on plates a forming the sides of the
ashpit C; D is the back plate of fireplace and E the front plate of same; F is the
back plate of combustion chamber; f is a fire clay dividing tile to more equally-
divide the products of combustion passing to each of the upper back smoke
chambers; G G are the loose side tiles in the fire place A for protecting the metal
sides of the fire place and supplying highly heated air on the top of the fire to
better complete the combustion of the gases. ggare the perforations in the top.
end of the tiles G G through which the air from the ashpit escapes over the top of
the fire. H H are similar tiles protecting the frout and back plates. II are the
firebars and K the fire door. LL are the upper back smoke chambers provided
with doors for cleaning or removing and replacing tubes. J are arched tops on
the upper back smoke chambers L, as the arches give a freer radiation of heat
therefrom than if the tops were made flat.
.
M M are the upper range or set of tubes which are secured to the plates k k at
back and the plates pp at front by annular removable caps hereinafter
described. N N are the front smoke chambers with doors n n for cleaning or
removing the tubes, and which convey the smoke and products of combustion.
downwards from the upper groups of tubes M M to the lower groups 00, which
are also secured by caps to the plates kk and pp. P is the flue or lower smoke.
chamber leading from the tubes OO to the base Q of the chimney R. S is the.
stove casing with doors T T in front for access to the inner doors n n in the front
smoke chambers N N, and U U are similar doors at back. tt are perforations in.
the casing to admit an air current between same and the smoke chambers.
openings in the base continuation of the front and back tube plates k and p for the-
passage of air.
V is the hot air collecting chamber or reservoir above the stove,.
and W is the duct for conveying the hot air from the chamber V to wherever it
may be required for heating or drying purposes. ww are baffle plates on inner
face of hot air collecting chamber V, and casing S.
Trare
Referring now to Figures 6, 7 and 8, which illustrate the removable cap or cover
for securing the tubes on the tube plates, k is the perforated tube plate in which
the tube M is a loose fit, c is the removable cap or cover with inclined lugs d which.
engage under the catches e; f₁ is a space left in the cap for expansion and
contraction of the tube lengthwise; the catches e are rivetted or suitably attached.
to the plate.
Having now particularly described and ascertained the nature of my said inven--
tion and in what manner the same is to be performed I declare that what I.
claim is :-
1. In a stove or apparatus for heating air and having one or more inlets for the
air to be heated and one or more outlets for the air after having been heated,.
the combination of a central furnace constructed as a gill stove, one or more
smoke chambers at the back of the said turnace and in communication therewith,.
a set of flow tubes parallel with the sides of the furnace, one or more front smoke-
chambers between which and the said back smoke chambers the said flow tubes.
communicate, a return set of tubes below and parallel with the set of flow tubes.
and leading from the frout smoke chambers, a back flue into which the return set
of tubes discharge this flue being in communication with the chimney, and one or
more air inlets at the lower part of the stove, all substantially as and for the
purposes herein before described and shown in the accompanying drawings.
2. In a stove or apparatus for heating air which has tubes fitting into perforations
in the sides or walls of the smoke chambers, a tube fitting loosely into its.
perforations and projecting at both ends through said perforations, in combination.
with removable annular caps having grooves to receive the tube ends and the
necessary packing, the said caps having also exterual inclined lugs, and projecting-
snugs on the sides of the smoke chambers engaging with the said lugs when the
caps are turned axially upon the tubes, substantially as and for the purposes.
hereinbefore described and shown in the accompanying drawings.

page_text: 3. The general arrangement and combination of parts constituting the improved
stove or apparatus for heating air, all substantially as and for the purposes herein-
before described and shown in the accompanying drawings.
Dated this 19th day of March 1896.
J. C. MEWBURN & ELLIS,
55 and 56 Chancery Lane, London, Chartered Patent Agents.