Improvements in Furnaces and similar Heating Apparatus.
Year: 1893

page_text: Date of Application, 22nd Aug., 1893
Complete Specification Left, 22nd May, 1894-Accepted, 11th Aug., 1894
PROVISIONAL SPECIFICATION
Improvements in Furnaces and similar Heating Apparatus.
A communication by WILLIAM HENRY LAIRD, of 132, Nassau Street, New York,
in the County and State of New York, United States of America, Gentleman.
I, GEORGE CECIL DYMOND, M. Inst. M.E., of The Agency for Foreign Patent
Solicitors, 6, Lord Street, Liverpool and 6, Bank Street, Manchester both in the
County of Lancaster and 323 High Holborn in the County of Middlesex, Patent
Agent, do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in furnaces and similar heating apparatus,
and particularly to that class of such devices wherein a down draft is employed to
facilitate the combustion of the fuel, and the invention consists in a certain improved
construction which will now be described.
In carrying out the invention a casing is provided having double walls between
which is enclosed a water space. In the upper part of this casing is arranged a
fuel magazine, the lower end of which opens into the top of the fire-pot, beneath
which fire-pot is hung a grate.
The lower portion of the fire-pot and the grate are supported on an annular
partition or band projecting inwardly from the lower part of the shell or casing
just above the ash-pit and the fire-pot is of less diameter than the shell so that an
annular gas space or chamber is formed between the casing and the fire-pot, which
chamber connects with the chimney.
A series of tubes or flues are arranged vertically in this gas space or chamber
having their lower ends projecting through the annular band into the ash-pit and
at their upper ends these tubes are bent inwardly and passed through the upper
walls of the fire-pot. In the lower portion of the wall of the fire-pot is formed a
series of openings leading from said fire-pot into the annular gas space or chamber
surrounding the fire-pot.
The fire being kindled on the grate, the fuel descends from the magazine and
there being no outlet for the products of combustion at the top of the fire-pot, the
same can only pass off through the openings in the lower wall of the fire-pot into
the annular gas chamber. The combustion is supported in part by air from the
ash-pit passing directly through the grate and in part by air supplied to the fire-pot
through the vertical tubes arranged in the gas chamber.
This invention also contemplates a construction wherein is employed instead of
the series of vertical tubes, one large annular tube or flue surrounding the fire-pot
and communicating with the interior thereof through openings in the upper walls
thereof. This flue communicates at its base with the ash-pit and in order to carry
off the products of combustion, a series of short horizontal flues are provided in
line with the grate, said flues communicating between the base of the fire-pot and
the said annular gas chamber between the casing and the fire-pot.
Another feature of the invention is the provision of steam jets in the ash-pit for
creating a draft through the grate and also through the air flues.
This invention further contemplates a construction wherein the air tubes or flues
ure arranged outside the casing and communicate between the upper part of the
fire-pot and the ash-pit and are provided with dampers whereby the draft through
these flues may be regulated at will.
A further feature of the invention is the construction and arrangement of the
draft flues for carrying away the products of combustion from the base of the
fire-pot. In order to attain the best results, the grate is arranged at a slight

page_text: distance below the bottom of the fire-pot, whereby an annular gas space is formed
surrounding the lower end of the fire-pot with which space the draft flues
communicate at their lower ends. In order to prevent the accumulation of ashes,
cinders, etc., in this gas-space whereby the draft might be interfered with, the same
is provided with a sloping bottom, and in order to further avoid this trouble the
lower edge of the fire-pot wall is provided with depending fingers whereby this gas
space is to a certain extent closed off from the fire-pot. In order to guard against
the formation of clinkers, etc., on the fire-pot walls and to render the same easily
removable, the fire-pot is provided with a series of inwardly projecting vertical
ribs serving to hold the fuel slightly away therefrom.
This invention further contemplates certain improvements in the construction of
the furnace in a series of separate and independent rings or sections adapted to be
set one upon the other, together with means for securing such rings or sections
together.
The object of this employment of a series of sections is partly to cheapen the
cost of the apparatus and partly to utilize to the greatest degree the heat from the
products of combustion, by providing a series of water chambers, whereby hot
water or steam may be employed for heating purposes.
To this end, each ring or section is provided with double walls whereby a water
chamber is formed therein, and in this space is arranged a partition. Each of the
sections is further provided with a water chamber at its rear which communicates
through two ports with the chamber in the section by ports formed on opposite
sides of the partition, which partition is carried across the water chamber, also
dividing it into inlet and outlet compartments. When the rings are secured
together, these separate compartments in the different sections are caused to
communicate with one another so that while the furnace is in use a current of
water is caused to circulate through each of the several sections.
To prevent the escape of gas from the furnace, in the upper walls of the magazine
a series of holes leading into the gas chamber or into the chimney is provided and
the magazine cover is formed with a tight fitting cap plate resting on the upper
edge of the magazine and also with a partition adapted to fit into the magazine
below the holes.
Dated this 21st day of August 1893.
WM. P. THOMPSON & Co.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Furnaces and similar Heating Apparatus.
A communication by WILLIAM HENRY LAIRD, of 132, Nassau Street, New York,
in the County and State of New York, United States of America, Gentleman.
I, GEORGE CECIL DYMOND, M. Inst., M.E., of The Agency for Foreign
Patent Solicitors, 6 Lord Street, Liverpool and 6 Bank Street, Manchester,
both in the County of Lancaster and 323 High Holborn in the County of
Middlesex Patent Agent, 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 relates to certain improvements in that class of furnaces or
heating apparatuses in which a down draught of air through the fire-pot is
employed to facilitate the combustion of the fuel, and the object of the invention
is to provide a furnace which shall present certain important advantages and
economies over other devices heretofore in use, all as will be hereinafter fully set
forth. The novel features of the invention will be carefully defined in the claims.
In the accompanying drawings three forms of the furnace are illustrated.

page_text: Figure being a vertical longitudinal section of one form of the furnace and
Figure 2 a similar view of the second form of the furnace.
Figure 2x is a view similar to Figures 1 and 2 but illustrating the third form
of the furnace, which is more particularly adapted for steam and hot water heating
and Figure 3 is a vertical partial section taken at right angles to the section shown
in Figure 2*.
Figure 4 is a perspective view showing the general appearance of the furnace
illustrated in Figures 2 and 3 and Figure 5 is a perspective detail view of the
fire-pot or combustion chamber shown in Figure 2x and to be referred to more
particularly hereinafter.
Referring first to Figure 1, 1 represents the casing having, as shown, double
walls in which is enclosed a water-jacket. In the upper part of the casing is
arranged the fuel magazine 2, the lower end of which opens into the upper part of
the fire-pot 3, beneath which fire-pot is mounted the grate 4 of any suitable
construction.
The lower part of the fire-pot 3 and grate 4 are supported by an annular
partition or band 5 projecting inwardly from the lower part of shell 1 just above
the ash-pit 6 and the fire-pot 3 is of a less diameter than said shell 1 whereby an
annular gas-space 7 is formed surrounding the fire-pot, which gas-space 7
communicates with the outlet (not shown) to the chimney.
9, 9, are a series of air-tubes or flues, vertically arranged in the space 7 and
having their lower ends projecting through the band 5 and communicating with the
ash-pit 6. At their upper ends, these tubes 9 are bent inwardly and pass through
the upper part of the walls of the fire-pot 3 and communicate therewith. In the
lower portion of the wall of the fire-pot 3 is formed a series of openings 10 leading
therefrom into the gas-space 7 which surrounds the fire-pot.
The fire being kindled on the grate, the fuel descends from the magazine 2,
assuming a conical form as indicated by the dotted lines. There being no outlet
for the gases at the top of the fire pot, the products of combustion can only pass off
through the openings 10 surrounding the base of the fire-pot, into the gas-space 10
surrounding the fire-pot 3 and thence to the chimney. As the fuel in the upper
part of the fire-pot becomes heated it will be partially decomposed and will give off
inflammable gas which will mix with a suitable quantity of air, which air is
supplied to the top of the fire-pot through the vertical flues 9 and the resulting
mixture will be drawn down toward the point of combustion at or near the level of
the grate, at which point they will become ignited and will combine with a further
supply of air entering the fire-pot directly through the grate, to produce almost
pure carbonic acid gas which will pass off through the openings 10 to gas-space 7
and thence to the chimney.
It will be understood that by this combination of the up draught through the
grate bars and the down draught through the fuel at the top of the fire-pot
almost perfect combustion takes place even wheu highly carbonized material as
lignite, soft or bituminous coal, etc., is used as fuel, and that the product of
this combustion is almost pure carbonic acid gas with little or no carbon in
suspension. Thus it will be understood that the furnace has advantages of economy
for use in large cities where the smoke nuisance has of late come to be of prime
importance and is also advantageous for ordinary use, since even with the hard
coals a great economy is effected.
In the second form of the invention, illustrated in Figure 2, the casing is
composed of a lower ring and a drum surrounding the fire-pot, said drum having
hollow walls forming a water jacket. The interior of the drum is in communi-
cation with the chimney and between the two sections of the drum, namely, the
lower ring and the drum proper is arranged an annular diaphragm or partition 5
formed about the lower edge of an air-tube 11, which surrounds the fire-pot and
corresponds to the tubes 9 in the first figure.
The grate 4 is arranged at the base of the fire-pot 3 and the fuel magazine 2 has

page_text: a close fitting cover and communicates at its lower end with the fire-pot in the
usual manner.
The air-tube is somewhat larger in diameter than the fire-pot, whereby an
annular space or air flue 12 is left between the two, and said air-tube is also smaller
in diameter than the drum 1, whereby an annular gas chamber 7 is left surrounding
the same.
A series of draught flues 10 are formed through the lower portion of
the fire-pot wall and extend across the space 12 between the same and the
air-tube 11 into the gas-space 7.
The air tube 11 is closed at its upper end but is in communication with the top of
the fire-pot 3 just below the magazine 2 through apertures in the walls of the fire
pot as clearly seen and said air-tube is also open at its lower end to the ash-pit 6
from which it draws its supply of air.
Mounted on suitable supports in the ash-pit 6 just below the grate 4 is a steam
pipe 13 in the form of a coil provided with jets 14 adapted to admit steam into the
lower end of the air-tube 11 and through the grate 4 into fire-pot 3. The steam so
admitted greatly augments the draught but is non-essential to the invention.
Referring to the third form of the invention shown in Figures 2, 3, 4 and 5,
A is the shell or casing and B the ash-pit provided with the usual ash-door. C is
the grate pivotally hung at c at the base of the fire-pot D and adapted to be rocked.
E is the fuel magazine opening at its base into fire-pot D and provided with a
cover and G, G, are air-tubes or flues leading from the ash-pit B below the
grate C to the upper part of the fire-pot D and corresponding to the tubes 9 in
Figure 1 or the Hue 12 in Figure 2. H, H, are draught flues leading from the
lower end of the fire-pot D above the grate to the outlet to the chimney.
As seen in Figure 3, the air-tubes G are carried through the shell A exterior to
the same and are provided with dampers g whereby the draught may be regulated.
By this arrangement one is enabled to regulate the draught to a nicety, and the
cost of construction is considerably lessened, these air-tubes being separate castings
with open ends, the. lower of which communicates with the ash pit B through an
opening in the shell and the upper end of which communicates through an
opening g² in shell A. with an interior horizontal tube g³ extending across the space
between the fire pot D and shell A.
A second feature of the third form of the invention is the construction and
arrangement of the draught flues H for conveying the products of combustion away
from the base of the fire-pot D. In the first and second forms of the invention a
construction is shown in which is employed in lieu of these flues, a large annular
space next the shell and completely surrounding the fire pot, the upper end of
which space communicates with the chimney and the base communicates with the
base of the fire-pot through several short horizontal flues or openings in the fire-pot
wall.
In order to avoid this expensive construction, the grate C is arranged at a
slight distance below the base of fire-pot D, whereby an annular gas-space I is
formed, with which space I communicate the lower ends of flues H. To prevent
the accumulation of ashes and cinders in space I the same is provided with a sloping
bottom i and to further avoid this danger, the fire-pot wall is provided with depending
fingers, whereby this space is partially separated from the fire-pot D.
To render any clinkers which may form in the fire-pot easy of removal, the walls
thereof are provided with vertical ribs b, whereby the fuel is held slightly away
from the walls.
The invention further contemplates the construction of the furnace in a series of
separate rings adapted to be set one on the other, and means for securing the rings
together, the object being to reduce the cost and to render the furnace easy of
assemblage and this construction will now be described.
1 is the base ring or section having a flat bottom and forming the ash-pit B
On this is mounted the section 2* having the form of a conic frustum and provided
with openings g' over which fit the ends of air tubes G. On this section 2 is
mounted the ring 3 having grate bearings c depending below the upper edge of

page_text: section and arranged so that
opening in one of the tubes G.
Lu
Mounted on section 3" is the section 4* having the fire-pot D of less diameter
than section 4* whereby a water space or chamber 4* is formed containing draught
flues H.
The upper wall or cover 5* of section 4* is provided at its central opening where
it joins the lower end of magazine E with an annular seat in which is set the
thimble 5* forming the next higher section of magazine E and cover 5* is also
provided with a series of openings forming the mouths of flues H. Over section 4*
fits section 6 having an annular chamber 6x projecting interiorly at a slight
elevation above cover 5. The central perforation 6 of chamber 6* surrounds
section 5* of the magazine, a free passage being left about the same for the passage
of the gases from flues H.
Mounted on section 6ª is section 8 similar to section 4. This section has a
chamber 8 arranged above its base whereby a space is left between chambers 6×
and 8 which is provided with a central wall or tube 8b fitting on tube 5° and
forming the next section of magazine E. Between tube 8 and the wall of section 8
are arranged in chamber 8 which corresponds with space 4*, the short flues 8ª.
Mounted on section 8 is the crown section_10x having a central depending
tube 10 forming the mouth of the magazine E and having the outlet 10° to the
chimney. Said crown section is also provided with oppositely arranged cleaning
doors 10° affording access to its interior.
Thus it will be seen that the waste gases passing from the fire-pot take their
course through flues H thence into the chamber formed between section 4* and
section 6, thence through the central perforation 6b into the chamber between
sections 6 and 8, thence through flues 8 into section 10* and thence through the
outlet 10 to the chimney.
The object of this series of sections is partly to cheapen the cost and partly to
utilize the greater part of the heat by providing water-chambers, whereby water
may be heated and the walls of the flues prevented from burning out.
Mounted on the section 3ª which is hollow is a water chamber J (Figure 2×)
having a diaphragm dividing it into two compartments.
One of these com-
partments has a closed top and is connected to a return header j³ (Figure 4). The
diaphragm extends across the internal space of section 3 and each of the
compartments of chamber J has a port communicating with the hollow of section 3ª
on opposite sides of the said diaphragm. Thus the water enters section 3ª which
surrounds the space 1 and is exposed to a high heat by way of one port passes
completely around the section and escapes by the way of the other port back into
the other compartment of chamber J, whence it passes through an opening in the
top of said compartment up into a water chamber K formed on the section 4*
(Figure 5).
Chamber K is likewise divided into compartments k* and k¹ by partition k which
is continued across the hollow 4* and the water from section 3* enters com-
4×
partment. The compartments k*, k¹ have ports communicating with space
on opposite sides of partition so that the water circulates around the fire-pot D
and Hues H escaping through the outlet port to the compartment which like the
compartment of chamber J has an open top corresponding with an opening in the
bottom of a chamber L formed on the section 6".
The arrangement of the ports and compartments of chamber L are similar in
every respect to the chamber J and section 8 is provided with a water chamber M
similar to chamber K. From chamber M the water flows through an outlet
tube m' to the flow header m (Figs. 2 and 4).
To secure the sections together, openings are provided in the partitions of the
several water chambers J, K, L, and M, through which openings bolts Nx pass
whereby the sections are secured in place by means of nuts. In order to dispense
with other bolts the sections are provided with overlapping flanges or lips x, which
prevent them from turning upon bolts N*.

page_text: To permit the escape of gas from the top of the magazine to the chimney instead
of into the room, the upper part of the walls of magazine E are provided with
perforations e and the cover F is provided with a tight fitting cap-plate resting on
the edge of the magazine and with a depending partition fx loosely fitting the
magazine below the openings e.
As it is obvious some alterations may be made in the construction and arrange-
ment shown herein my correspondent does not wish to limit himself to the forms
shown exactly. For instance, a greater or less number of the sections may be
employed and the parts may be arranged and constructed in somewhat different
forms.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me by
my foreign correspondent I declare that what I claim is :-
Firstly. In a furnace having a fire-pot, grate and ash-pit, air-flues leading from
below the grate level to the upper part of the fire-pot and adapted to supply air
for supporting combustion, and gas flues leading from the base of the fire-pot to
the outer air and adapted to convey away the waste gases from the fire-pot,
substantially as specified.
Second. In a furnace having a shell provided with a fire-pot of less diameter
than the shell and a grate and ash-pit arranged beneath the said fire-pot, an air
flue leading from below the grate level to the upper part of the fire-pot, whereby
air is supplied to the fire-pot to support combustion, said flue being arranged in
the space between the shell and fire-pot, and gas flues leading from the base of the
fire-pot into the base of the space between the shell and fire-pot and adapted to
convey the waste gases from the fire-pot into said space, whereby the current of air
flowing through the air flue is heated and the draught increased, substantially as
specified.
Third. In a furnace such as that specified in Claim Second, the arrangement of
the air flue in the form of a cylindrical or circular partition surrounding the fire-
pot, as shown in Figure 2 of the drawings.
Fourth. In a sectional boiler, the fire-pot section having double walls whereby
a fire-pot and a surrounding water-space are formed therein, said fire-pot having a
contracted upper portion forming the mouth of the fuel magazine, a partition
extending across said annular water space from the outer to the inner wall and to
the mouth of the fuel magazine, and inlet and outlet ports arranged on opposite
sides of said partition, substantially as described and shown in Figures 2x and 5 of
the drawings.
Fifth. The combination in a furnace, of a fire-pot section having double walls,
whereby an annular water space is formed therein, a grate below the same whereby
-an annular gas space is formed between the grate and fire pot sections, a series of
gas flues extending through said water space and connecting at their lower ends
with the gas space and a series of air flues extending horizontally across said water
space and connecting at their inner ends with the interior of the fire-pot above said
gas-space, substantially as described and shown in Figs. 2 and 5 of the drawings.
Sixth. The combination in a furnace, of a casing, a grate arranged therein, a
fire-pot section having its lower portion arranged above the grate, whereby an
annular gas-space is formed between said grate and fire-pot section, said fire-pot
section being provided with a series of fingers depending into the gas-space and a
series of draught flues extending through the hollow of the fire-pot section and
connecting at their lower ends with said gas-space, substantially as described and
shown in Figures 2* and 5 of the drawings.
Seventh. The combination in a furnace, of a grate, a fire-pot section arranged
above said grate and having double walls whereby a central fire-pot and a
surrounding water-space are formed therein, a series of gas-flues extending
vertically through said water-space and a series of air-flues extending horizontally

page_text: through said water-space and connecting at their inner ends with the interior of the
fire-pot section above the lower end of the gas flues, substantially as set forth.
Eighth. In a boiler furnace, the combination with a grate, of the fire-pot section
above the same and having an annular water-chamber surrounding the fire-pot,
upwardly leading gas-flues or tubes passing through the water chamber, and the
draught tubes external to the fire-pot section and communicating with the upper
part of the fire-pot, so that the currents of air pass upwardly outside the walls of
the furnace inwardly into the upper part of the fire-pot, downwardly through the
same and then upwardly through the internal gas-flues of the fire-pot section
substantially as set forth.
נית
1004
WM. P. THOMPSON & Co.,
Agents.