IMPROVEMENTS IN KILNS OR OVENS FOR FIRING POTTERY, BRICKS, TILES, AND OTHER CERAMIC WARE, AND FOR BURNING LIMESTONE
Year: 1875

page_text: LETTERS PATENT to Charles Malpas, of West End, Woore, in the
County of Salop, for the Invention of "IMPROVEMENTS IN KILNS OR
OVENS FOR FIRING POTTERY, BRICKS, TILES, AND OTHER CERAMIC WARE, AND
FOR BURNING LIMESTONE."
Scaled the 14th September 1875, and dated the 23rd March 1875.
PROVISIONAL SPECIFICATION left by the said Charles Malpas at
the Office of the Commissioners of Patents, with his Petition, on
the 23rd March 1875.
I, CHARLES MALPAS, of West End, Woore, in the County of Salop,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN KILNS OR OVENS FOR FIRING POTTERY, BRICKS, TILES, AND OTHER CERAMIC
WARE, AND FOR BURNING LIMESTONE," to be as follows:-
According to my Invention I arrange a number of separate kilns or
oyens in a ring. Each oven communicates at bottom by means of a
passage provided with a damper, with a circular flue common to all
the ovens, which communicates by means of other flues with a central
chimney. Each oven has an opening at top opening into the atmo-

page_text: sphere, and closed with a cover, and a communication is also established
between the tops of the contiguous ovens by means of passages provided
with dampers.
Below the floor of each oven are formed a series of flues, by which
they are made to communicate both with each other and with a moveable
fire, arranged in the following manner:-Beneath the ring of ovens is
formed a circular passage, with which each of the ovens communicates
by means of a central hole opening into the before-mentioned flues. In
the circular passage is a fire-box mounted on wheels running on rails, so
that it can be shifted from beneath one oven to the next one. This
moveable fire-box consists of a close casing having two furnaces, com-
municating in the centre with one common opening at top, by which
the fire-box communicates with the before-mentioned central hole of the
oven. The fire-box is supported on toothed racks in gear with pinions
carried by the under framing, to which motion can be imparted simul-
taneously so as to raise or lower the fire-box by means of a worm
rotated by a hand wheel and in gear with a worm wheel on a shaft
having bevil pinions in gear with other bevil pinions on the shafts of
the before-mentioned pinions that work the racks. Thus when it is
desired to shift the fire-box from one oven to the next it is first lowered
slightly by turning the hand wheel, after which it is moved beneath the
opening of the next oven, and is again raised so as to fit closely against
the same.
The operation of firing the kilns is as follows:-Assuming a certain
number of the ovens to be charged with goods to be fired, the fire-box is
placed beneath the opening of the first of such ovens, the openings of
all the other ovens being closed by covers. The flame from the fire-box
passes through the before-mentioned flues under the floor of the oven,
and issues through a number of vertical passages at the sides of the
oven, as also through a central opening in the floor. After passing up
among the goods the flames or hot gases escape through the before-
mentioned passage at the top of the oven into the top of the next one,
where they descend, imparting heat to the goods therein, and issue
through the flues under the floor into the passage by which the second
oven communicates with the third one, and so on, the hot gases alter-
nately passing up one oven and down the next until they arrive at the
bottom of the last one, which is put in communication with the before-
mentioned circular flue that leads to the chimney, the heat of the gases

page_text: being then so reduced or exhausted that it cannot injure the fresh goods
contained in the last oven. Thus the heat issuing from the oven that is
being fired is most effectually utilised in drying and partially firing the
goods contained in all the other ovens of the series, so that when the
firing of the first oven is completed and the fire box is shifted to the
next one, it will only take a comparatively short time to complete
the firing of the goods contained therein. The firing of the first oven
having been completed, it is cut off from the series by closing the
damper in the communicating passage, and the opening at top com-
municating with the atmosphere is uncovered at pleasure so as to allow
the fired goods to cool. At the same time another oven charged with
fresh goods is put into communication with a series under the operation
of firing at the other end; thus there is always a series of ovens being
fired and a series being cooled, the goods of the latter being removed
when cold and replaced by fresh goods, and the oven added to the firing
series in rotation.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles Malpas in the Great Seal Patent Office on
the 22nd September 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
MALPAS, of West End, Woore, in the County of Salop, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of March, in the
year of our Lord One thousand eight hundred and seventy-five, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Charles Malpas, Her special
license that I, the said Charles Malpas, my executors, administrators,
and assigns, or such others as I, the said Charles Malpas, my executors,
administrators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel

page_text: Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN KILNS OR
OVENS FOR FIRING POTTERY, BRICKS, TILES, AND OTHER CERAMIC WARE, AND
FOR BURNING LIMESTONE," upon the condition (amongst others) that I,
the said Charles Malpas, my executors or adminstrators, by an instru-
ment in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said In-
vention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Charles Malpas, do hereby declare
the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the accom-
panying Sheet of Drawings, and to the figures and letters marked
thereon, that is to say :—
According to my Invention I arrange a number of separate kilns or
ovens in a ring. Each oven communicates at bottom by means of a
passage provided with a damper with a circular flue common to all the
ovens, which communicates by means of other flues with a central
chimney. Each oven has an opening at top opening into the atmosphere
and closed with a cover, and a communication is also established between
the tops of the contiguous ovens by means of passages provided with
dampers.
Below the floor of each oven are formed a series of flues, by which
they are made to communicate both with each other and with a move-
able fire arranged in the following manner:-Beneath the ring of ovens.
is formed a circular passage, with which each of the ovens communi-
cates by means of a central hole opening into the before mentioned flues.
In the circular passage is a fire-box mounted on wheels running on rails,
so that it can be shifted from beneath one oven to the next one. This
moveable fire-box consists of a close casing having two furnaces com-
municating in the centre with one common opening at top, by which
the fire-box communicates with the before mentioned central hole of the
oven; the fire-box is supported on toothed racks in gear with pinions
carried by the under framing, to which motion can be imparted simul-
taneously, so as to raise or lower the fire-box by means of a worm
rotated by a hand wheel and in gear with a worm wheel on a shaft

page_text: having beviled pinions in gear with other bevil pinions on the shafts of
the before-mentioned pinions that work the racks. Thus, when it is
desired to shift the fire-box from one oven to the next it is first lowered
slightly by turning the hand wheel, after which it is moved beneath the
opening of the next oven, and is again raised so as to fit closely against
the same.
The operation of firing the kilns is as follows:-Assuming a certain
number of the ovens to be charged with goods to be fired the fire-box is
placed beneath the opening of the first of such ovens, the openings of
all the other ovens being closed by covers; the flame from the fire-box
passes through the before mentioned flues under the floor of the oven
and issues through a number of vertical passages at the sides of the
oven, as also through a central opening in the floor.
After passing up
among the goods the flames or hot gases escape through the before-
mentioned passage at the top of the oven into the top of the next one,
where they descend, imparting heat to the goods therein, and issue
through the flues under the floor into the passage by which the second
oven communicates with the third one, and so on, the hot gases alter-
nately passing up one oven and down the next until they arrive at the
bottom of the last one, which is put in communication with the before-
mentioned circular flue that leads to the chimney, the heat of the gases
being then so reduced or exhausted that it cannot injure the fresh goods
contained in the last oven. Thus, the heat issuing from the oven that
is being fired is most effectually utilised in drying and partially firing
the goods contained in all the other ovens of the series, so that when the
firing of the first oven is completed, and the fire-box is shifted to the
next one, it will only take a comparatively short time to complete the
firing of the goods contained therein. The firing of the first oven
having been completed it is cut off from the series by closing the damper
in the communicating passage, and the opening at top communicating
with the atmosphere is uncovered at pleasure, so as to allow the fired
goods to cool. At the same time another oven charged with fresh goods
is put into communication with the series under the operation of firing
at the other end, thus there is always a series of ovens being fired and
a series being cooled. The goods of the latter being removed when cold
and replaced by fresh goods, and the oven added to the firing series in
rotation.
It will be readily understood that the above described arrangement

page_text: of my Defore described improved construction of ovens or Kimms; Lig. 2
shews a transverse section of the same on line W, W, Fig. 1.
Fig. 3 shews a vertical section to an enlarged scale through the centre
of one of the kilns, and an end clevation of the moveable furnace.
Fig. 4 shews a vertical section through the flues between two con-
tiguous kilns.
Fig. 5 shews a section similar to Fig. 3 with the aperture for the
admission of the flames from the travelling furnace closed.
Fig. 6 shews a side elevation of the moveable furnace; and Fig. 7 is
a sectional plan of the same, shewing the gearing for moving, raising,
and lowering the furnace.
As shewn on the Drawing there is a series of 24 kilns A arranged in
a circle, each of which communicates by a passage B at bottom with a
circular flue C, which in its turn communicates with the central
chimney D through the flues E, E. Each kiln has an opening Gat
top, which may either be made to communicate with the atmosphere
by raising the cover H or to communicate with the next kiln through
the passage I provided with a rotating valve or damper K, by which
this communication can be shut off. Each kiln has an opening L on
the inner side, through which the goods are charged into and discharged
from the kiln, and has side holes, which can be opened to examine the
contents during firing. It has also a central opening M at bottom for the
admission of flame from the moveable furnace N arranged to travel on rails
in a circular passage O formed beneath the kilns. In the lower part of
each kiln are formed a number of flues and passages, the arrangement
and object of which will be understood on reference to the various
sections of the kilns A³, A2, A3, A4, shewn at Fig. 1, A' being a section
on line 1-1, Fig. 3; A is a section on line 2-2; A³, a section on
line 3-3; and A' a section on line 4-4.
The flames in passing up from the furnace through the opening N
pass thence into the radial flues P, P, whence they issue through
openings P' and P³ into other radial flues Q, Q, from which they issue
through the opening Q¹ in the centre of the kiln, and through the

page_text: annular passage Q round the sides thereof. By this arrangement it
will be seen that the flames and hot gases are equally distributed in the
kiln, thus producing a perfectly uniform heat throughout the entire
kiln. The cover H being closed and the damper K turned so as to allow
of a communication being established between the top of the kiln that
is being fired and the next one, the flames and hot gases will issue from
the top of the first into the top of the second, in which they will descend,
passing downwards through the before-mentioned passages, as indicated
by the arrows in Fig. 5, and issuing from the passages P through
openings P³ into circular flues R, R', formed beneath P, and communi-
cating either with the flues C by means of the passage P provided with a
damper B, or with the bottom of the next kiln through the passage B
provided with the rotating valve or damper B³.
The mode of operating with the scries of kilns is as follows:-I will
assume that all the kilns except those at Z, Fig. 1, are filled with goods,
that those at X, X, are being fired, while those at Y, Y, are cooling after
having been fired, those at Z being about to be emptied of fired goods
and filled with fresh goods. The moveable furnace N having been
placed under the kiln A' the dampers B', B³, and cover H are closed,
while the damper K is opened, so that the hot gases pass up through
the kiln A and then down the kiln A³. The opening M of this kiln
being closed by the swing damper M', as shewn at Fig. 5, while the
valve B³ in the passage B through which it communicates with the
kiln A is opened, the hot gases will consequently pass from the bottom
of A³ into the bottom of A³. Here they will again rise and pass into the
top of A¹, and so on alternately up and down through the several kilns,
until they arrive at the bottom of the last in the series marked X, in
which the damper B¹ being open while the valves B³ and K are closed
the gases will escape into the flue C, and thence to the chimney, having
during their passage through the kilns imparted the greater part of the
heat to the goods contained therein, and thus when the firing of the
goods in A* has been completed it will be found that those in A³ will be
almost completely fired, those in A² somewhat less so, and so on to the
twelfth one, where the heat of the gases will have been so reduced as
not to be detrimental to the fresh goods contained therein. The furnace
is now moved from A to A³, the cover H having been previously raised
from A, and the valves K, B', and B³ being closed, while the swing
damper M¹ to the kiln A³ has been opened to allow the furnace N to be

page_text: placed in position.
The communications between the several ovens in
the series X are then reversed, so that the gases pass down those that
they passed up through before, and vice versa, and the first kiln of the
series Z having been in the meantime filled with fresh goods it is added
to the series X by opening the communications between it and the last
of the series X, and also the communications between it and the chimney,
the communication between which and the kiln that before was last of
the series X being now closed.
When the kiln A³ has been fired by the direct application of the
furnace for, say, one hour and a half, the firing of the goods will be
found to have been completed, and the furnace can be removed to A³,
and so on, so that there will be twelve kilns fired every eighteen hours.
As the goods in the series Y become cooled by the passage of air through
them they are discharged from the kilns in rotation and charged with
fresh goods, there being always three ovens in the series Z which are
being emptied and filled, leaving nine others in the series Y, which have
each about thirteen hours and a half to cool in.
The revolving dampers K are by preference constructed as shewn at
Fig. 4, consisting of two refractory cheeks K' carried by slabs K³ sup-
ported on an iron bottom, to which is attached a spindle K³ supported 2
in bearings and passing down to the space O beneath the kilns, where
it is turned by hand so as to turn the damper into the closed or open
position. The damper is enclosed at top by fire-brick slabs K' and a
cover K³, which can be removed to gain access to the damper.
The damper B³ is constructed in the same manner as K, and is turned ?
by means of the rod B. The damper B' is opened and closed by means
of a crank handle or wheel turning the pinion 6 by bevil gear, the
damper having a rack at bottom in gear with the pinion b¹.
The moveable furnace N consists of a double fire-box communicating
with one middle opening N¹ at top, where it is provided with an annular
trough N filled with sand, into which dips an annular flange M³ secured
to the under side of the kiln casing round the aperture M, so that when
the furnace is brought into position and raised up a gas-tight joint is
formed between it and the opening M of the kiln. Holes n are pro-
vided in the neck of the furnace fitted with slides, so
air may be admitted to regulate the heat in the oven. For raising the
furnace to the mouth of the oven it is provided on its under side with
that more or less

page_text: TACKS IN gear with pinions on SmarUS IN carried by the carriag
the furnace, the shafts N' being made to turn simultaneously so as to
raise or lower the furnace by means of a shaft N° and bevil gearing
rotated by a worm and worm wheel, as shewn at Figs. 6 and 7.
The furnace may have attached to it trucks or tenders containing the
fuel, as shown.
The dampers K, B', B³, M¹, and the cover H are all provided with
sand traps, as shewn, to secure a gas-tight connection.
It will be observed that the floor of the circular passage O is on a level
with the general ground line, so that the kilns A. are raised considerably
above this level, access being gained to them by means of inclines and
steps V, V.
The central space within the kilns may be roofed in and utilised as
the manufactory, store rooms, &c.
It will be seen that by arranging and working kilns in the manner set
forth above a considerable saving of fuel, space, and labour may be
effected, great uniformity of heating and cooling may be secured, and
cvolution of smoke may be prevented.
Having thus described the nature of my Invention and in what
manner the same is to be performed, I wish it to be understood that I
do not claim generally the use of a series of kilns or ovens wherein the
flames and hot gases are made to pass from the one kiln consecutively
through the others before escaping to the chimney, as I am aware that
this has been before proposed, but I claim,—
First. The arrangement, substantially as herein described, of a series
of kilns or ovens all communicating with a common flue leading to a
chimney, and also with each other, and with the atmosphere at top and
bottom, by means of openings and passages or flues provided with
valves or dampers, while they are consecutively made to communicate
at bottom with a moveable furnace travelling in a passage beneath the
ovens or kilns.
Second. The peculiar arrangement of flues or passages in the lower
part of each kiln herein-before described and shewn on the Drawings,
whereby a uniform distribution of heat throughout the kiln is attained.

page_text: Third. The before described construction of moveable furnace arranged
to be raised and lowered to or from the apertures in the bottom of the
kilns, through which the flames and hot gases are admitted.
In witness whereof, I, the said Charles Malpas, have hereunto
set my hand and scal, this Eighteenth day of September, in the
year of our Lord One thousand eight hundred and seventy-five.