Year: 1885

page_text: I THOMAS CARDER, of Paignton, in the county of Devon, Mechanical Engineer
do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in the construction of kilns and to the
arrangement of flues, furnaces and other parts connected therewith whereby I obtain
greater economy, uniformity in the quality of the productions, simplicity of working,
and adaptability for the treatment and burning of bricks, tiles, retorts, enamel
and clay ware, lime, cement, coke, carbon, and other productions requiring to be
subjected to kiln and furnace heats.
In carrying out my invention I group my kilns together in process of construction
so as to form a continuous or semi-continuous series of segmental or semi-circular
domed kilns or oven-chambers. These oven-chambers I connect to each other by
openings or wiffin spaces built at two different elevations and having a flue space
between so as to form one complete kiln, whereby the heat generated in one section
becomes regenerative to the other sections of the series. These kilns are each
connected by means of separate buttress chimnies to a hot air tube built over the
dome of a centrally placed vaulted chamber common to the furnace and damper
approaches of the entire series of kilns-such hot air tube being connected to the
central tube of a suitably placed chimney or shaft. By this arrangement I effect a
more perfect combustion of the fuel and heating products than is generally the case
and at the same time I cause the kilns as far as is practicable to consume their
own smoke.
For the purpose of obtaining a greater uniformity of temperature of the heat
passing from the furnaces into the burning chambers I build lateral openings or
flues from furnace to furnace in each series of furnaces of each oven-chamber,
whereby each chamber not only becomes heated by the furnaces as heretofore, but
each and all of the furnaces become independently, and collectively pre-heated for
the reception of fuel-These lateral furnace communications allow the glowing heats
of the series of furnaces on fire to become interchangeable and common to each
other before passing into the oven-chamber whereby every part of such chamber
becomes more uniformly heated.
I provide openings extending from these lateral furnace communications to the
external parts of the piers or buttresses between each furnace, in order to admit
the external air by valves or otherwise for the better regulation of the internal

page_text: temperature, and where convenient, for the purpose of serving as channels for the
introduction of hydro-carbon products, gas, or other inflammable substances.
At the base of each dividing wall of the oven-chambers I provide an arrangement
for effecting inter-communication between chamber and chamber and for non-inter-
communication according as the various stages of manufacture and burning may
require.
An overhead exhaust flue common to the whole series of chambers is employed
in order to abstract heat from the cooling chamber, and to enable me to convey it
into any "green" chamber by means of horizontal dampers so arranged that by
their use I am enabled to employ the said overhead exhaust flue in connection with
a central steaming off flue built below the floor of the central funnel or firing
chamber and extending thence to the wiffin spaces grouped round the central tube
of the main chimney stack and by which, steam or moisture from the drying
chambers passes away into the external air. The main tube of the chimney becomes
thereby relieved of excessive moisture and consequent proportionate non-reduction
of temperature, whereby a more perfectly even draught is secured.
I construct a chimney flue arranged in the buttress of each oven and regulated
by a fire clay or asbestos or other kind of damper, by which communication is
effected between each oven-chamber and the elevated hot air-tube leading to the
chimney.
G. F. REDFERN,
4, South Street, Finsbury, London,
Agent for the Applicant.

page_text: I THOMAS CARDER, of Paignton, in the county of Devon, Mechanical Engineer, 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 improvements in the construction and method of action
of kilns or ovens, and new arrangement of flues, furnaces and draughts in connection
therewith, whereby greater economy, uniformity of results and quality of productions,
simplicity of working, and reliable adaptability for the treatment and burning of
bricks, tiles, retorts, enamel and every species of ceramic wares.-Cement, lime,
ultramarine-blue, charcoal and other productions requiring to be subjected to kiln,
oven and furnace heats may be secured.
In carrying out my invention, I group my kilns together in process of construction
so as to form a continuous or semi-continuous series of segmental or semi-circular
domed kilos or tunnel shaped ovens.
These kilns or oven-chambers I connect to each other by newly invented and
peculiarly arranged openings or wiffin spaces, or flues, built at two different elevatons
having a transverse flue between, common to both elevations, so as to form one
perfect whole, whereby the heats and flames generated in one section are carried
forward or backward at will so as to become regenerative to the other sections of
the series, and otherwise made available for use in the initial stages of kiln and
oven workings.
These kilns or oven chambers, each and severally I connect by means of separate
wall or buttress channels to a hot air tube of large calibre, built over the dome of a
specially arranged and centrally placed vaulted chamber-space common to the
internal furnaces and damper approaches and openings of the entire series of kilns,
and further by way of such hot air-tube to a suitably placed chimney shaft. The
effect of such an arrangement being to create such a degree of perfect combustion
of the fuel as to practically consume its own smoke and thereby secure the maximum
amount of work from the fuel employed.
I provide for further greater uniformity of temperature in the various furnaces
discharging their heats into the burning or oven chambers by a new and novel
method of building lateral openings or flue slits from furnace to furnace in each
series of furnaces of each chamber, whereby each and all of the furnaces become
pre-heated for the reception of fuel, and whereby each furnace ultimately, instead
of as heretofore burning with a separate or individual heat, burns in common with
its neighbouring furnace by means of these interchangeable flue-slits and by which
a more uniform heat ranging from furnace to furnace flows into the kiln or oven
chamber in connection therewith.
I provide openings to extend from these lateral furnace communication channels
to the external part of the piers or buttresses between each furnace in order to
admit the external air by valves or otherwise for the better regulation of the

page_text: internal temperature, and where convenient, for the means of introducing hydro-
carbon products, gas or other inflammable substances.
I provide a new and novel arrangement at the base of each dividing wall of the
various kilns for the inter communication between chamber and chamber, or for
the closing of communication as the various stages of manufacture and burning
may require.
I provide an overhead or elevated exhaust and hot air flue common to the whole
series of chambers built longitudinally in the external walls, and connected to each
kiln or oven chamber by a cooling flue forming the hollow space in the upper
portion of the internal division walls between each kiln.
I build or leave openings into this cooling flue or hollow space of the division
walls at the upper far end of each oven chamber or kiln from the wicket way
entrance so that the cold air entering at such wicket way may drive the hot air
forward from the entrance-way through these division wall openings into the
cooling flue, and thence into the common exhaust hot air flue.
I also provide flues to connect this hot air flue with the furnaces of each flue so
that the heated gases from the cooling flues may be economised at will in the
burning chamber.
I construct a central steaming off flue, built below the floor of the central tunnel
or firing chamber, or according to the nature of the ground, at the base of the
inside buttress wall, and extending from thence to the wiffin spaces of the main
stack or chimney.
I connect this steaming off flue with each chamber by a suitably placed bottom
flue, so that whilst the hot air from the longitudinal hot air flue can be made to
flow into any given chamber filled with green bricks the steam generated from these
green bricks can be drawn away to the steaming off flue and thence to the wiffin
spaces of the main chimney, and by which means the central tube of the chimney
is relieved from the presence and obstructive action of steam or heavy damp
vapour.
I construct a specially arranged chimney flue in the inner buttress of each kiln
or oven chamber regulated by a fire clay damper, asbestos or other kind of damper,
and by which, communication is effected between each oven and the central elevated
main flue tunnel leading to the central tube of the chimney.
In order to enable my invention to be fully understood I will proceed to describe
the same by reference to the accompanying drawings, in which figure 1 is a plan
partly in section of an oval or elliptical form of furnace or kiln as constructed
according to my invention. For convenience of description the said figure. is
divided into three parts A B and C. The part A represents a plan of one end of
the kiln, with the main flue tunnel extending to the chimney, in section; the
part B represents a horizontal section or plan of the centre portion of the kiln on
the line B in figure 2 hereinafter described, and the part C represents a horizontal
section at the ground level of the other end of the kiln, showing the main flue
tunnel extending to the chimney in section.
Figure is a transverse sectional elevation of the kiln. Figure 3 is a longitudinal
sectional elevation of a portion of the outside of the kiln. Figure 4 is a part
longitudinal section of the kiln.
Similar letters in all the figures represent similar parts.
a, a are the heating chambers which I divide from one another by hollow walls b
extending from the floor to the top of the kiln and having their bases specially
arranged as shown in figures 2 and 4. c is a communication pit at one end of each
heating chamber extending to a depth of about eighteen inches below the floor level
of kiln; d figure are the wiffin flues at the base of division walls b forming one
side of the pit c and extending from a little below the kiln floor level downwards,
and communicating with the transverse flue or opening e, in which is a damper e¹,
and is constructed so as to obtain access from the outside of the kiln for effectually
closing and sealing the same with sand or clay daub when required; f figure 4,
are the wiffin spaces or flues on the other side of the division walls b in the next

page_text: chamber, the said wiffin spaces rising from the kiln floor level, upwards; g figure 4
are the cooling flues in the division walls and communicating with one end of the
chambers a by openings h h through the upper portion of the division wall b. i is
the hot air flue (figure 2) communicating with each of the cooling flues g, by which
means very intense or modified heats can be discharged from any hot or cooling
chamber into any green chamber for steaming off purposes; a damper j, shown in
figure 2, regulates the action of the said flue.
are the furnaces constructed upon a semi-retort principle, that is to say,
wherein the fuel is made to yield or evolve its gases. I supply these gases with
heated oxygen passing through the glowing outside fuel, and from the hot air flue i
whereby cold air is prevented entering the kiln and coming into contact with the
goods therein; are the dampers for regulating the supply of hot air from
the flue to the furnaces i¹. kare the lateral openings or flues connecting the
furnaces in each series of furnaces of each chamber a, as shown in figure 2;
1 figure 2 are the chimney flues connecting each of the oven chambers a with the
main flue tunnel or hot air tube m, dampers being arranged in each of the said
flues . The hot air tube or tunnel m is connected to the chimney n, the said
tunnel m being formed over the dome of the centrally placed vaulted chamber n¹
which serves for stoking the furnaces i', arranged in the interior of the kiln, and as
means of access to the dampers in the flues 1, o and o¹.
o is the central steaming off flue, whilst o¹ is the alternative steaming off flue
leading to the wiffin spaces which act as chimnies around the middle tube of main
shaft or chimney n.
p, p are the wicket ways leading to each oven chamber a, and q are sight or spy
holes in the said chambers; r are ventilation pipes in the chamber n¹ and 8 is the
passage way leading to the said chamber.
The operation of my improved kiln is as follows I find it advantageous that
five or six adjacent chambers a, in succession be first filled with green or partially
dry bricks or the like, and communication opened between each of the said
chambers by opening the dampers e' in each of the transverse spaces or openings e
between the said chambers and that the next chamber forward be shut off or
disconnected from the last of the series of filled chambers by closing the damper e¹
in the opening or flue e, between the said chambers; fire is then introduced into
the furnaces of the first chamber of the series charged with bricks or the like, these
fires are slowly increased until it is judged that the moisture from the green bricks
or the like in the first and second chambers a of the series has been driven off;
the furnaces are then fully charged with fuel, the flames rapidly rush and
spread from furnace to furnace and reverberate into the said chambers a, and
speedily heat the whole mass of bricks or other goods within to a glowing red or
white heat intensity as may be required.
The dampers of the flues 1, of the first three or four chambers having been
closed and those of the fifth or sixth chambers having been opened the waste
heats of the first or burning chamber are carried forward to the fifth or sixth of
the series driving off their moisture and pre-heating them in readiness for full
firing when the first and earlier chambers have been sufficiently fired off..
Meanwhile the seventh or other chambers beyond have been filled with green
bricks and each as soon as filled is in succession "taken on," that is, their separate
dampers in the flues are opened. The dampers of number 5 or 6 are then
closed and the damper e¹, over the communication pit c between number 6 and
number 7 is drawn, whilst damper e¹, between number 8 and number 9 chamber is
closed, thus causing the heats of the firing chambers to be advanced forward
another stage, this process is repeated chamber by chamber until the whole circuit
is made. By the time the circuit of all the chambers contained in the kiln is
made-facilities for bringing the cooling flues g, hot-air flue i, and steaming-off
flues o and o¹, into action have arisen, and these separately or conjointly are now
made to yield their important results by the simple adjustment of their several
dampers as occasion requires.

page_text: Although I have shown in the drawings my improved kiln arranged in an oval
or elliptical form in plan it will be understood that it may as hereinbefore
described be arranged in any other convenient form.
By reference to the accompanying drawings it will be seen that I have
endeavored practically to lay hold of the various technical and scientific principles
involved in the various stages and processes of steaming off, burning and firing,
cooling and equalizing results of kiln operations, and to reduce them to an easy
efficient and economic control.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is,
Firstly. The herein described general arrangement and construction of kiln
operating substantially in the manner and for the purposes hereinbefore described
and represented in the accompanying drawings.
Secondly. The arrangement and construction of the main flue tunnel m with its
communicating flues l, substantially as set forth.
Thirdly. The construction of the division walls b with perforated upper
portions and cooling flues g, substantially as set forth.
Fourthly. The arrangement of hot-air flue i, by which heated air can be
conveyed from any of the heated or cooling chambers at one and the same time
to any of the distant green chambers, and to the furnaces of the burning chamber
for the supply of heated oxygen or atmospheric air, substantially as herein before
described and represented in the accompanying drawings.
Fifthly. The arrangement of steaming off flue o, or o¹, having a distinct and
separate communication with the wiffin spaces grouped around the internal tube of
the shaft or chimney n, whereby the moist vapours and steam are caused to ascend
to the external air without checking the draught of the main middle tube, sub-
stantially as set forth.
Sixthly. The arrangement at the base of the division walls for controlling
communication between the chambers of communication pits c, each having a
series of wiffin flues below the floor level on the one side, and a series of wiffin flues
above the floor level on the other side with a transverse flue or opening e
between the walls controlled by a damper in the said opening, substantially as
set forth.
Seventhly. The arrangement of lateral furnace flues opening from one furnace
to another whereby the temperature of the various furnaces is made equal by
inter-communication before sending their heats into the various oven chambers of
the kiln substantially as hereinbefore described and represented in the accom-
panying drawings.