IMPROVEMENTS IN STOVES OR AIR HEATING APPARATUS
Year: 1880

page_text: LETTERS PATENT to Samuel Cleland Davidson, of Belfast, in the County of
Antrim, Ireland, Gentleman, for an Invention of "IMPROVEMENTS IN STOVES
OR AIR HEATING APPARATUS.”
PROVISIONAL SPECIFICATION left by the said Samuel Cleland Davidson
at the Office of the Commissioners of Patents on the 5th March 1880.
SAMUEL CLELAND DAVIDSON, of Belfast, in the County of Antrim, Ireland,
Gentleman. "IMPROVEMENTS IN STOVES OR AIR HEATING APPARATUS.”
The improvements have reference to the stoves or heating apparatus described in
the Specification of previous Letters Patent granted to me and dated 15 December
1877, No. 4773, inasmuch as the improved stove hereinafter described has the
fire place situated between a series of flat vertical chambers, which chambers are
end on to and extend right and left of the fire, into each alternate chamber of
which the products of combustion from the fire are admitted at the upper end, and
are drawn down through same into a chamber or general flue formed beneath the
ash plate of the fire place, as therein described, while in the other alternate chambers
air is admitted below, and, becoming heated by contact with the sides of the
chambers, ascends in the reverse direction to the currents of the products of
combustion, and escapes from these chambers at the upper end. And the herein-
after described improvements have also reference to the improvements in stoves or
heating apparatus described in the Specification of previous Letters Patent granted
to me and dated 14th March 1879, No. 1011, inasmuch as at the back of the fire
place there is a smoke box with a direct communication door between it and the fire,
as therein described, and a general main smoke flue may, when preferred (although
not herein described), be used beneath the entire stove in place of the more confined
flue immediately below the ash plate of the fire place.
The present improvements consist in having the series of flat vertical chambers
situated upon the two sides of the fire place only, and not extending over the top
of the fire place as formerly, and these two series of chambers are constructed as
follows:-The partition walls between the chambers are formed of sheet metal
of suitable thickness, cut to requisite size and shape, and having holes cut at
suitable-intervals round the edges through which staying bolts pass from one end
of the series of chambers to the other, and these plates are kept apart from one

page_text: another so as to form the chamber spaces between them when bolted through from
one to the other, by means of cast iron ribs or loose flanges which are laid between
them round the edges, and which have holes in them corresponding with the holes
in the sheet metal partition walls, so that the staying bolts may pass through both
direct in alternate order. Or when it is desired to have these partition walls of cast
metal instead of sheet metal these ribs or flanges may be cast upon the plates
round their edges, the holes for bolting them through from one to the other being
cast into the flanges at suitable intervals. The flanges extend entirely around
these metal partition walls with the exception of where openings are required into
the chambers for inlet and outlet of the products of combustion and of the air, and
they thus form with the partition walls enclosed chambers, which are so arranged
that each alternate one has openings which only communicate with the fire place
above and main smoke flue below, while the openings to the other alternate
chambers communicate only with the external air. -
Special openings are however also provided in the smoke chambers to facilitate
cleaning operations, but these openings are usually to be kept closed by means of
movable doors or plugs, except when required for cleaning purposes.
The series of chambers thus formed is attached to another similar series by
_vertical metal plates to which they are bolted in such a manner that there is a
space enclosed between them and the plates to form the fire place. Suitable snugs
or ledges are placed upon these plates and upon the flanges of the chambers'
partition walls next this fire place to carry the fire grate and ash plate. In the
front plate which connects these two series of chambers there is a door at the
bottom communicating with the main smoke flue, and above it another door
communicating with the ash pit and lower part of the fire place, and which door is
so arranged to act as regulator of the supply of air to the fire. At an interval
above this there is another door by which fuel can be admitted to the fire, and this
door may be fitted with a talc panel or window through which the light and glow
of the fire may be observed, and so add a cheerful appearance to the stove. Or the
fuel can, if preferred, be fed in through the top of the fire place, which in that case
would be fitted with a suitable door, but when the front fuel door is used I prefer
closing in the top of the fire place with a plate with light ribs or gills cast upon it.
When the stove is intended to act as a slow combustion stove the fire bars of the
fire grate may be dispensed with and the fire be placed upon the ash plate, which
may be protected by a fire tile, and in this case bars would be fixed across the door
way into the lower part of the fire place so as to keep the fire back from the door,
leaving an air space between the door and it. In this way the air is not admitted
underneath the fire, but only through the front bars which are across the doorway,
and the ash pit is thus entirely dispensed with; but where rapid combustion is
required the ash pit and ordinary fire bar arrangement are necessary to give a more
free supply of air to the fire.
In the back plate which connects the two series of chambers together there is an
opening below for letting the smoke pass from the main smoke flue below the ash
plate into the smoke box at back, and at top there is another opening fitted with a
valve door, operated by a handle from without the stove for giving direct
communication from the fire into the smoke box. The chimney from the smoke
box is preferably connected at the upper end of it, but if an under flue to the
chimney be required it may be connected with the under end of the smoke box, or
the smoke box may be entirely done away with and the chimney connected from
below with the centre of the main smoke flue. Upon each of the sides of the fire-
place which are next the series of flat vertical chambers there is used a metal plate
with ribs or flanges round its edges to form between it and the sides of the flat
vertical chambers a hollow chamber, and this plate thereby forms a false side to
the fire. This hollow chamber has independent communication with the open air
by means of an opening provided in the front plate of the stove, and which connects
with a corresponding opening in lower front corner of this false side, and along the
upper edge of the false side there is a long horizontal narrow slit (or perforations

page_text: may be substituted for this slit), but there are no other openings provided to the
chamber which is behind the false side. The object of this arrangement is to keep
the fire itself from touching the sides of the flat vertical chambers and prevent its
destructive effect upon the metal of the sides, and at the same time form an air
heating chamber, from which a supply of very highly heated air is being
continuously drawn in a thin strata (or in small jets if perforations are used) across
the current of the gases arising from the fuel, which gases (especially when a
limited supply of air is given to the fire, as is the case when slow combustion is
aimed at) come from the fuel in a very partially consumed state, but on meeting
the highly heated strata of fresh air issuing from the slits in the false sides the
combustion is instantly effected in a very perfect manner, thus enabling a gaseous
coal to be used in this stove, even when used as a slow combustion stove, without
liability of the flues becoming choked up with condensation of tar and other such
products from the incomplete combustion of such coal, with the exception of the
ordinary soot, and even of this there is not much as the smoke by this arrangement
is very well burnt before leaving the fire place, so that there is but little deposit
of soot in the flues. The independent communication which these false sides have
with the outer air always allows admission of a sufficient supply of oxygen to
complete the combustion of the unconsumed gases, even when the supply of air to
the under part of the fire is exeeedingly limited to attain a slow rate of combustion.
Similar arrangements of false sides may also be provided on back and front sides
of the fire when desirable, but as a rule it is preferable to have a fire tile in these
places to protect the back and front plates, and also to check the radiation of heat
in those directions, but it is desirable to allow the radiation through the metal
false sides to operate as freely as possible into the chambers on right and left of
the fire, as the temperature of the hot gases is thereby somewhat reduced before
striking upon the upper part of the partition walls of these chambers, and the heat
is consequently more distributed over the chambers. The stove should be set
upon a hollow stand, from which the air heating chambers can draw their supply
of air, and this hollow stand can be supplied with fresh air from the external
atmosphere when so desired; or it can be arranged that the external air could be
shut off, and the air within the apartment drawn through the stove over and over
again to obtain a high temperature in the apartment without reference to the
freshness of the air.
The whole stove is intended to be enclosed in a casing of ornamental casting of
any desirable design, an air space being left between the casing and the stove,
which air space communicates with the air supply place below the stove and also
with the hot air exit opening in the casing over the top of the stove. For heating
large warehouses or for special drying purposes where large and strongly heated
stoves would be used this outer casing should be made of double sheeting of sheet
iron with non-conducting material between the sheetings, similarly to the casing
described in Specification of my previous Patent, No. 1011, dated 14th March
1870

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Samuel Cleland Davidson in the Great Seal Patent Office on the
4th September 1880.
SAMUEL CLELAND DAVIDSON, of Belfast, in the County of Antrim, Ireland,
Gentleman. "IMPROVEMENTS IN STOVES OR AIR HEATING APPARATUS.”
The improvements have reference to the stoves or air heating apparatus described
in the Specification of previous Letters Patent granted to me, and dated 15th
December 1877, No. 4773, inasmuch as the improved stove hereinafter described
has the fire place situated between two series of flat vertical chambers, which
chambers are end on to and extend right and left of the fire, into each alternate
chamber of which the products of combustion from the fire are admitted at the
upper end and are drawn down through the same into a chamber or general flue
formed beneath the asphalte of the fireplace, as therein described, while in the other
alternate chamber air is admitted below, and becoming heated by contact with the
sides of the chambers ascends in the reverse direction to the currents of the products
of combustion, and escapes from these chambers at the upper end.
And the hereinafter described improvements have also reference to the improve-
ments in stoves or heating apparatus described in the Specification of previous
Letters Patent granted to me, and dated 14th March 1879, No. 1011, inasmuch
as at the back of the fireplace there is a smoke box with a direct communication
door between it and the fire, as therein described, and a general main smoke flue
similar in arrangement to that described in the said Specification may when
preferred (although not herein described) be used beneath the entire stove in place
of the more confined flue immediately below the asphalte of the fire place.
The present improvements consist in having the series of flat vertical chambers
situated upon the two sides only of the fire place, and not extending over the top
of the fire place as formerly, and these two series of chambers are constructed as
follows:
The partition walls between the chambers are formed of sheet metal of suitable
thickness, and cut to the requisite size and shape, and having holes cut at suitable
intervals round the edges through which staying bolts pass from one end of the
series of chambers to the other, and these plates are kept apart from one another
(so as to form the chamber spaces between them when bolted through from one
to the other) by means of cast iron ribs or loose flanges which are laid between
them round the edges, and which have holes in them corresponding with the holes
in the sheet metal partition walls, so that the bolts may pass through both direct
in alternate order; or when it is desired to have the partition walls of cast metal
instead of sheet metal these ribs or flanges may be cast upon the plates round their
edges, the holes for bolting them through from one to the other being formed in
the flanges at suitable intervals. The flanges extend entirely around these metal
partition walls, with the exception of where openings are required in the chambers
for inlet and outlet of the products of combustion and of the air, and they thus
form with the partition walls enclosed chambers, which are so arranged that each
alternate one has openings which only communicate with the fireplace above and
the main smoke flue below, while the openings to the other alternate chambers
communicate only with the outer air.
Special openings are however also provided in the smoke chimney to facilitate
cleaning operations, but these openings are usually to be kept closed by movable
doors or shutters, except when required for cleaning purposes.
The series of chambers thus formed is attached to another similar series by
vertical metal plates, to which they are bolted in such a manner that there is a
rectangular space enclosed between them to form the fire place.

page_text: The bottom of this space is closed by a plate which forms the bottom of the ash
pit, and the top is closed by another plate, which I term the radiator plate,
having light ribs or gills upon the outer or upper side.
These plates for closing the top and bottom of the fire place are carried upon
suitable snugs or ledges which are placed upon the ribs of the chambers and upon
the plates which connect the two series of chambers together, and they also have
suitable ledges for supporting the fire grate.
In the front plate which connects the two series of chambers there is a door at
the bottom communicating with the main smoke flue, and above it another door
communicating with the ash pit and lower part of the fire place; this door is made
to slide from side to side, and so act as a regulator of the supply of air to the fire.
At an interval above this there is another door by which fuel can be admitted to
the fire, and this door may be made with open ornamental iron work, such as shown
in the accompanying Drawings, fitted with tale panelings, so that the openings
may be closed therewith, but the light and glow of the fire may be observable
through it, and so give a cheerful appearance to the stove.
Should it for some particular purpose be preferred to have the fuel fed in
through the top of the fire place the upper fuel door in the front plate can be
dispensed with, and in place of the radiator plate already described as closing the
top of the fire place another plate fitted with a suitable door may be substituted,
through which door the fuel can be introduced to the fire, but for ordinary
purposes I prefer the fuel door to be in the front plate, and the top of the fire
place to be closed by the radiator plate, as shewn in the accompanying Drawings.
When the stove is intended to act as a slow combustion stove the fire bars of
the fire grate may be dispensed with, and the fire be placed upon the ashplate,
which may be protected by a fire tile, and in this case bars would require to be
fixed across the doorway of this part of the fire place in order to prevent the fire
from falling forward, and to keep an air space between it and the door for
regulating the supply of air to the fire. In this way the air is not then admitted
underneath the fire, but only through these bars which are across the doorway,
and the ash pit is thus entirely dispensed with, but when rapid combustion is
required the ash pit and fire bar arrangement are necessary to give a more free
supply of air to the fire, and in the accompanying Drawings it is the latter arrange-
ment that is shown.
In the back-plate which connects the two series of chambers together, there is
an opening below for letting the smoke pass from the main flue beneath the ash
plate into the smoke box at the back, and at the upper end there is an opening
fitted with a valve door operated by a handle above the smoke box for giving
direct communication from the fire into the smoke box.
The chimney from the smoke box is preferably connected at the upper end of it,
but if an under flue from the stove to the chimney be required it may be con-
nected with the under end of the smoke box, or the smoke box may be entirely
done away with and the chimney connected with the centre of the main smoke
flue from below, in which latter case the openings in the back plate giving com-
munication from the smoke box to the fire place and to the main smoke flue
would be closed up and done away with altogether.
Upon each of the sides of the fire place formed by the series of flat vertical
chambers I use a metal plate with ribs or flanges round its edges to form between
the side and it a hollow chamber, and this plate therefore forms a side to the fire,
and I term these plates "false sides."
The hollow chambers behind these false sides have independent communication
with the open air by means of openings (marked U, U, in Figure 1 of the
accompanying Drawings) provided in the front plate of the stove, and which
connect with corresponding openings in the lower front corner of the false sides,
and along the upper edge of each false side there is a long horizontal narrow-slit
(or perforations may be substituted for this slit), but there are no other openings

page_text: to the hollow chambers enclosed behind the false side. The object of this arrange-
ment of false side is to form an air heating chamber from which a supply of very
highly heated air issues as long as the fire is burning in a thin stratum (or in
small jets if perforations are used) across the current of the gases arising from the
fuel, which gases (especially when a limited supply of air is given to the fire, as is
the case when slow combustion is aimed at) come from the fuel in a very partially
consumed state, but on meeting the highly heated stratum of fresh air issuing from
the slits in the false sides the combustion is instantly effected in a very perfect
manner, thus enabling a gaseous coal to be used in this stove, even when used as a
slow combustion stove, without liability of the flues becoming choked up with
condensation of tar and other such products from the incomplete combustion of
such coal, with the exception of the ordinary soot, and even of this there is not
much, as the smoke by this arrangement is very well burnt before leaving the
fire place, so that there is consequently but little deposit of soot in the flues. The
independent communication which these false sides have with the outer air always
allows admission of a sufficient supply of oxygen to complete the combustion of the
unconsumed gases, even when the supply of air to the under part of the fire is
exceedingly limited in order to attain a slow rate of combustion.
These false sides also keep the fire itself from touching the ribs of the series of
flat vertical chambers, and thereby prevent its destructive effect on them.
Similar arrangements of false sides may also be provided on the back and front
sides of the fire place; or a fire tile may be substituted in these places to protect
the back and front plates, and also to check the radiation of heat in those directions,
but it is desirable that the radiation through the false sides should operate as
freely as possible into the chambers on right and left of the fire, as the temperature
of the hot gases is thereby somewhat reduced before striking upon the upper part
of the partition walls of these chambers, and the heat is consequently more evenly
distributed over the chambers than if this radiation were prevented.
The stove is set upon a hollow stand from which the air heating chambers can
draw their supply of air, and this hollow stand can if required be made close fitting
to the ground all round, and be supplied with fresh air by a pipe or flue from the
external atmosphere, or this hollow stand may be used for the general smoke flue
described in the Specification of my previous Letters Patent, No. 1011, of 1879,
but in this case the inlet openings for the air to the air heating chambers, and the
outlet openings for the smoke from the smoke chambers must be situated as
therein described, instead of as shown in the accompanying Drawings.
The whole stove is intended to be enclosed in a casing of ornamental iron work
of any desirable design, an air space being left between the casing and the stove,
which air space receives its supply of cold air from small openings or holes made
along the lower part of the casing, and as it opens into the general hot air exit
chamber over the top of the stove a current of air is continually passing between
the casing and the stove which assists in keeping the casing cool.
For heating large warehouses, or for special drying purposes, where large and
strongly heated stoves would be used, this outer casing should be made of double
sheeting of sheet iron with non conducting material between the sheetings, similar
to the casing described in the Specification of my previous Letters Patent, No. 1011,
of 1879.
The accompanying Drawings illustrate the construction of the apparatus.
Figure 1 is a front elevation of the stove in its complete form.
Figure 2 is a vertical section of the stove through the centre from front to
back.
Figure 3 is a vertical section across the fire place through the false sides, and
through a smoke chainber on each side of the fire.
Figure 4 is a similar section to Figure 3, but cutting through the air chambers
on each side of the fire instead of through the smoke chambers.
Figure 5 is a horizontal section just above the fire bars.

page_text: The letters which indicate the several parts are the same in each Figure, and are
as follows:-
A fireplace

page_text: improvements, all substantially as herein before describedd an représented in the
accompanying Drawings; and I further claim, the use in any stove fire places
of "false sides," constructed substantially as hereinbefore described, for promoting
the complete combustion of the partially consumed gases as they rise from the
fuel.
In witness whereof, I, the said Samuel Cleland Davidson, have hereunto set
my hand and seal, this First day of September, One thousand eight hundred
and aightv
S. C. DAVIDSON. (L.S.)