IMPROVEMENTS IN MEANS AND APPARATUS FOR SECURING RAPID, EFFECTIVE, AND ECONOMICAL COMBUSTION OF FUEL IN FURNACES FOR HEATING, MELTING AND OTHER MANUFACTURING OPERATIONS"
Year: 1883

page_text: LETTERS PATENT to James Howden, of Glasgow, in the County of Lanark,
North Britain, Engineer, for an Invention of "IMPROVEMENTS IN MEANS AND
APPARATUS FOR SECURING RAPID, EFFECTIVE, AND ECONOMICAL COMBUSTION
OF FUEL IN FURNACES FOR HEATING, MELTING AND OTHER MANUFACTURING
OPERATIONS"
PROVISIONAL SPECIFICATION left by the said James Howden at the Office
of the Commissioners of Patents on the 1st January 1883.
JAMES HOWDEN of Glasgow, in the County of Lanark, North Britain, Engineer,
"IMPROVEMENTS IN MEANS AND APPARATUS FOR SECURING RAPID, EFFECTIVE,
AND ECONOMICAL COMBUSTION OF FUEL. IN FURNACES FOR HEATING, MELTING, AND
OTHER MANUFACTURING OPERATIONS
"
This Invention consists principally in so arranging the supply of air to a furnace
that the quantity admitted above or below the fuel or at other parts may be
regulated, loss of heat and impairment of draught due to the throwing outwards
of heat being prevented, a more intense and rapid heat being obtained either by
natural or forced draught, and the heat which usually passes away wastefully
being utilised for the purpose of assisting the combustion of the fresh fuel, whilst
the comfort of the attendant workers is much increased.
The improvements are in part effected by enclosing the furnace front in which
are the firing and ashpit doors or openings with a casing of iron or other suitable
material, so as to form an air space which may be common to all the doors or
openings or be made with partitions and valves admitting of the separate
regulation of the quantities supplied to different parts. The iron casing has on its
outside fire and ashpit doors arranged by preference to close airtight especially
when a forced draught is used and there is an inner fire door attached to the outer
one in a position to serve the purpose of the ordinary furnace door, but with a
space between it and the outer door such space forming part of the air space; or
the inner door may be on separate hinges instead of being attached to the outer
door. An inner door may similarly be provided for the ashpit but will generally
not be required.

page_text: When a forced air supply is used the air is led from the fan or blower by a pipe
or convenient passage to the interior of the casing, from which the air may pass
into the furnace from the ashpit and above the grate through whatever openings
there may be in the inner furnace door at equal pressure and without any
provision for regulating or adjusting the distribution. It is however preferred to
have partitions in the air casing with valves for separately regulating the supplies
of air; and separate compartments with their valves may be arranged for supplying
air through hollow grate bars or through perforated side pipes in the furnace, the
air issuing from such hollow bars by perforations in the bars themselves or
through orifices in the bridge at the inner end of the furnace. With such
arrangements the admission of air may be regulated or adjusted with ease so as to
obtain the best results in actual practice; which cannot be done in ordinary
arrangements in which the admission is entirely uncontrolled. The improved
arrangements prevent not only waste of heat but also tho injury ordinarily caused
to workers and in other ways for want of such control, the air space between the 1
outer casing and the inner plating or brickwork of the furnace front preventing.
radiation of heat outwards and also increasing the draught when natural draught
is employed.
The Invention also in part consists in utilising the residuary heat of the furnace
gases by causing the heat which ordinarily passes wastefully up the chimney to
pass through a suitably placed series of pipes or passages of iron or firebrick or
other suitable material, so as to act on the air supplied by the blowing apparatus
such air being led through spaces or passages so as to pass in contact with the
pipes or partitions heated by the departing furnace gases and being thence led to
the casing at the front of the furnace. This part of the Invention will generally
be applied with a forced air supply, but in some cases it may be applied with
natural draught.
When the improvements are applied to a furnace having its firing door or doors
at a different side or sides from the working door or from the ashpit or other
opening the air casing may be constructed to embrace two or more sides of the
furnace; or it may be made in separate parts, which parts may be connected by
pipes or passages when a forced air supply is used; but such connection will not
be necessary when natural draught is used or when the air-moving apparatus is
applied so as to have an exhausting action on the gases leaving the furnace.
When using suitable modifications of the improved apparatus an open fire grate
may be dispensed with, the fuel being burned on a close hearth, to different parts
of which the air may be separately supplied.
In furnaces used for puddling and reheating purposes in iron works, and forges
the working doors for introducing the rabble or instruments for stirring or working
the iron, or for introducing and removing the masses of iron which have to be
heated, are covered in so far as may be necessary for the various operations but it
is not necessary to close them airtight as the air pressure inside of the furnace can
be regulated so as to be equal to the pressure of the atmosphere, whereby the
entrance of cold air will be prevented. In this way the great waste of iron which
ordinarily occurs through the action of cold air or of the oxygen of such air is
completely avoided.
In cases in which the construction and manner of using the furnace admit of it
hoppers for supplying the fuel may be combined with the improved apparatus or
arrangements herein before described; or any suitable known kind of mechanical
stoking apparatus may be employed with the view of diminishing the frequency
with which the fire doors require to be opened for supplying fuel.
It is an important advantage of the improvements herein before described that
with them smoke is almost entirely prevented, this result being obtained with
economy of fuel and with easy and certain working of the furnaces.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Howden in the Great Seal Patent Office on the 28th June
1883.
JAMES HOWDEN, of Glasgow, in the County of Lanark, North Britain, Engineer,
IMPROVEMENTS IN MEANS AND APPARATUS FOR SECURING RAPID, EFFECTIVE,
AND ECONOMICAL COMBUSTION OF FUEL IN FURNACES FOR HEATING, MELTING, AND
OTHER MANUFACTURING OPERATIONS "
My said Invention consists principally in so arranging the supply of air to a
furnace that the quantity admitted above or below the fuel or at other parts may
be regulated, loss of heat, and impairment of draught due to the throwing out-
wards of heat being prevented, a more intense and rapid heat being obtained, either
by natural or forced draught, and the heat which usually passes away wastefully
being utilised for the purpose of assisting the combustion of the fresh fuel, whilst
the comfort of the attendant workers is much increased.
My improvements are in part effected by enclosing the furnace front in which are
the firing and ashpit doors or openings, with a casing of iron or other suitable
material, so as to form an air space which may be common to all the doors or
openings, or be made with partitions and valves admitting of the separate regulation
of the quantities supplied to different parts.
When a forced air supply is used the air is led from the fan or blower by a pipe
or convenient passage to the interior of the casing, from which the air may pass
into the furnace from the ashpit and above the grate through whatever openings
there may be in the inuer furnace door at equal pressure and without any provision
for regulating or adjusting the distribution. I however prefer to have partitions in
the air casing with valves for separately regulating the supplies of air; and separate
compartments with their valves may be arranged for supplying air through hollow
grate bars or through perforated side pipes in the furnace, the air issuing from such
hollow bars by perforations in the bars themselves, or through orifices in the bridge
at the inner end of the furnace. With such arrangements the admission of air may
be regulated or adjusted with ease so as to obtain the best results in actual practice;
which cannot be done in ordinary arrangements in which the admission is entirely
uncontrolled. My improved arrangements prevent not only waste of heat but also
the injury ordinarily caused to workers and in other ways for want of such control,
the air space between the outer and the inner plating or brickwork of the furnace
front preventing radiation of heat outwards, and also increasing the draught when
natural draught is employed.
My Invention also in part consists in utilising the residuary heat of the furnace
gases by causing the heat which ordinarily passes wastefully up the chimney to
pass through a suitably placed series of pipes or passages of iron or firebrick or
other suitable material so as to act on the air supplied by the blowing apparatus
such air being led through spaces or passages so as to pass in contact with the
pipes or partitions heated by the departing furnace gases, and being thence led to
the casing at the front of the furnace. This part of my Invention will generally
be applied with a forced air supply, but in some cases it may be applied with a.
natural draught.
When using suitable modifications of my improved apparatus an open fire grate
may be dispensed with, the fuel being burned on a close hearth, to different parts
of which the air may be separately supplied.
In furnaces used for puddling and reheating purposes in iron works, and forges,
the working doors for introducing the rabble or instruments for stirring or working

page_text: the iron, or for introducing and removing the masses of iron which have to be
heated, are covered in so far as may be necessary for the various operations but it
is not necessary to close them airtight as the air pressure inside of the furnace can
be regulated so as to be equal to the pressure of the atmosphere, whereby the
entrance of cold air will be prevented. In this way the great waste of iron which 5
ordinarily occurs through the action of cold air or of the oxygen of such air is
completely avoided.
In cases in which the construction of the furnace and manner of using it admits
of it, hoppers for supplying the fuel may be combined with the improved apparatus
or arrangements herein described; or any suitable known kind of mechanical 1
stoking apparatus may be employed with the view of diminishing the frequency
with which the fire doors require to be opened for supplying fuel.
It is an important advantage of my improvements that with them smoke is
almost entirely prevented, this result being obtained with economy of fuel, and
with easy and certain working of the furnaces.
J
And in order that my said Invention and the manner of performing the same
may be properly understood I hereuuto append two sheets of explanatory drawings
to be hereinafter reforred to and representing various modifications of my improved
apparatus.
Figure. 1, on sheet, 1, of the accompanying drawings is a sectional end elevation
and figure, 2, is a longitudinal vertical section of a reverberatory heating furnace
as constructed with one modification of my improved arrangements. Figures 3,
and 4, are similar views of a second modification. Figures, 5, and 6, on sheet 2,
are similar views of a third modification, figure, 7, being a corresponding horizontal
section; and figures, 8, and 9, are similar views of a fourth modification. In these
drawings the same reference numerals are used to mark the same or like parts
wherever they are repeated.
In the modification shown in figures, 1, and 2, the furnace front is covered or
enclosed by a casing, 10, which forms an air chamber or space, and which whilst
preventing or diminishing wasteful and inconvenient radiation of heat, serves for
furnishing a heated and controlled supply of air to the furnace. In this modifi-
cation or example a forced air supply is employed, the air being made to pass
through the apparatus by a fan or blower (not shown) and first entering by a
pipe, 11, into an arrangement of pipes, 12, placed in the flue, 13, by which the
waste fire gases leave the furnace, so that some of the waste or residuary heat may
be taken up and utilised by the air. The pipes, 12, are fixed in end casings having
partitions arranged to cause the air to pass through sections of the pipes in
succession. From the heating pipes, 12, the air proceeds by a flue or passage, 14,
towards the front of the furnace, and dividing at the back of the ashpit, 15,
continues by branch flues, 16, at the sides into the lower part of the casing, 10.
The space inside of the casing, 10, is divided by partitions the flues, 16, first
communicating with spaces, 17, extending across the top, and the part within these
spaces, 17, 18, being divided by horizontal partitions into three compartments, 19,
20, 21, of which the top one, 19, gives the air access to the inner fire door, 22, the
middle one, 20, to hollow fire bars, 23, and the bottom one, 21, to the ashpit, 15.
The proportions of air admitted to the several compartments, 19, 20, 21, are
regulated or adjusted by means of valves, 24, 25, 26. The casing, 10, has on its
outside fire and ashpit doors, 27, 28, arranged by preference to close airtight
especially when a forced air supply is used as in the present example, and there is
an inner fire door, 22, attached to the outer one, 27, in a position to serve the
purpose of the ordinary furnace door, but with a space between it and the outer
door, 27, such space forming part of the air space. Or the inner door, 22, may be
on separate hinges instead of being attached to the outer door, 27. An inner door
may similarly be provided for the ashpit, 15, but will generally not be required.
The hollow fire bars, 23, communicate at their inner ends with a space formed in
the bridge, 29, and from this space the air passing through the fire bars is directed
upon the fuel by a number of jet orifices, 30, having a downward inclination.

page_text: Some air may also be made to issue from orifices (31) at the upper part of the
bridge, 29, so as to act on the fire gases above the fuel, as indicated in figures 6,
and 7. In front of the fire bars, 23, a door, 32, is fitted above the ashpit door, 28,
in the front casing, 10, to give access to the fire bars for any purpose; and this
5 door may be hinged by its bottom edge as shown or by its upper edge. Into the
furnace or firo space, 33, above the bars the air has access from the top casing
compartment, 19, partly through holes in the inner fire door, 22, partly through
holes, 34, below the fire door, and partly through perforations in pipes, 35, of
quadrantal section placed at each side of the fire space, 33, with their front ends
O open to the compartment, 19. With these arrangements the air supply is sub-
divided and introduced in separate jets entering at different parts of the furnace
whereby a very complete uniform and efficient combustion of the fuel is obtained.
When my improved arrangements are applied to puddling and other reverberatory
furnaces which are bound with iron plates and tie rods the plates forming the air
casing (10) may be arranged so as to form part.of the binding apparatus.
The second modification shown in figures, 3, and 4, is considerably simplified as
compared with the first modification, being arranged for the air being supplied by
natural draught, and with few separately controllable inlets. The air casing, 10, at
the front of the furnace is made with two compartments, 19, 21, into which air has
access from the atmosphere by valves, 24, 26. The fire bars, 36, are of an ordinary
kind resting on transverse bearers, 37, and can be withdrawn through the special
door, 32, provided for the purpose in the front casing, 10. A part of the air
entering the ashpit, 15, passes into the hollow bridge, 29, and issues thence through
downwardly directed orifices, 30, upon the fuel.
Figures 5, 6, and 7, sheet 2, show the application of a modification of my
improvements to a furnace having its firing door at the side instead of at the end
of the furnace. The air casing, 10, is shown as constructed to embrace the end and
one side of the furnace, with the enclosed spaces in communication; but if preferred
separate air casings may be applied to the end and side, or two or more sides may
have the air casing or casings applied to them. When a forced air supply is used
with separate air casings they must be connected by pipes or passages or be fitted
with branch pipes to receive supplies from the main air pipo but such communi-
cations will not be necessary when natural draught is used, or when the air-moving
apparatus is applied so as to have an exhausting action on the gases leaving the
furnace. In the modification shown in figures, 5, 6, and 7, the pipe, 11. from a fan
or blower communicates directly with the air casing, 10, and has access to the inuer
tire door, 22, at the side. At the end a horizontal partition with a valve, 26, fornis
a compartment, 21, which communicates with the ashpit, 15, and through it with a
pace in the bridge, 29, the air issuing thence by lower orifices, 30, in a downward
firection on the fuel. Upper orifices, 31, in the bridge, 29, direct air into the fire
gases to burn any combustible matters that might otherwise pass over the bridge,
hese orifices receiving their supply by a passage, 38, leading directly into the .
ridge from the lateral part of the air casing, 10, and provided with a regulating
alve, 39. Air can also enter the furnace or fire space, 33, through downwardly
aclined inlets, 34, across the end, these inlets being provided with a regulating
alve, 40.
In the modification shown in figures 8, and 9, the furnace or fire space, 33, is
onstructed with a closed hearth, 41, without fire bars. An opening, 42, which is
rdinarily closed by one or more firebricks is provided to give access to the hearth
ad for removing ashes, and an outer door, 32, is provided opposite each opening,
the air casing, 10. Passages, 43, formed below the hearth, 41, and provided
ith a regulating valve, 44, lead some air to the downwardly directed orifices, 30,
the bridge, 29; and side passages, 45, formed in the brickwork lead some of the
r to jet orifices, 46, in the sides of the furnace. There are also air inlets, 34,
low the inner fire door, 32, as in the other modifications. In this example a
e or passage, 14, is shown for leading the air to the lower part of the air

page_text: casing, 10, from heating apparatus such as is hereinbefore described with reference
to figures 1, and 2.
Having thus particularly described my said Invention and the manner of
performing the same I have to state that I do not restrict myself to the precise
details herein described or delineated but that what I believe to be novel and
original and claim as the Invention secured to me by and in terms of the herein-
before in part recited Letters Patent is :-
1. The improved combinations of parts herein before described for securing rapid,
effective, and economical combustion of fuel in furnaces for heating, melting, and
other manufacturing operations.
2. The combination with or application to a melting, heating or similar furnace,
of an air casing placed at the front or at one or more sides and arranged so that
the air supplied to the furnace passes through such casing substantially as and for
the purposes herein before described.
8. The combination of apparatus for heating air by the waste gases with one or
more casings formed with compartments and provided with regulating valves for
supplying air to the furnace or fire space by several inlets substantially as herein-
before described.
In Witness whereof I, the said James Howden have hereunto set my hand
and seal this twenty-fifth day of June in the year of our Lord One thousand
Jed and eighty-three.
Witness,
EDMUND HUNT.
Patent Agent
Glasgow.
JAMES
OWDEN 【L.S.)