IMPROVEMENTS IN POTTERY OVENS OR KILNS, AND GLASS AND OTHER FURNACES
Year: 1869

page_text: LETTERS PATENT to Henry Young Darracott Scott, of Ealing, in the
County of Middlesex, Lieutenant-Colonel Royal Engineers, for the
Invention of "IMPROVEMENTS IN POTTERY OVENS OR KILNS, AND GLASS AND
OTHER FURNACES."
Sealed the 2nd July 1869, and dated the 19th April 1869.
PROVISIONAL SPECIFICATION left by the said Henry Young Darracott
Scott at the Office of the Commissioners of Patents, with his
Petition, on the 19th April 1869.
I, HENRY YOUNG DARRACOTT SCOTT, of Ealing, in the County of
Middlesex, Lieutenant-Colonel Royal Engineers, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN POTTERY OVENS OR KILNS,
AND GLASS AND OTHER FURNACES," to be as follows:-
My Invention of improvements in pottery ovens or kilns, and glass and
other furnaces, consists in constructing and arranging fire-places, and
burning the fuel in pottery kilns or ovens, and glass and other furnaces
of ordinary construction somewhat on the principle or in the manner

page_text: shown and described in the Specification of my Patent, dated Aug 15th,
1868, No. 2554, for improvements in pottery or other kilns, in which the
kilns were described as being constructed in a novel and peculiar
manner.
My improved fire-places adapted for ovens, kilns, or furnaces of
ordinary construction consist of two or three sections or compartments
according to circumstances and the purpose for which they are to be
applied. The first section of the fire-place consists of an inclined hopper
or channel into which the green fuel is introduced. This part is
arranged either for perfect combustion or for imperfect combustion of the
coal with the production of gaseous fuel. The second section consists of
inclined fire-bars in continuation of the bottom of the hoppers, on to
which the fuel when warmed and partially coked descends and afterwards
passes from thence to the third section, which consists of a vertical
chamber into which the remains of the fixed portions of the fuel finally
sink for entire consumption. The second section may be sometimes.
omitted with advantage, and the fire-grate or furnace then consists of
the inclined hopper and the vertical chamber. The vertical chamber
offers facilities for the increase of flame at the expense of glow fire by
the application of the vapour of water.
The second feature of the Invention relates to the mode of bringing in
fresh air from the outer atmosphere at points at some little distance from
the furnaces employed in various manufactures. In pottery ovens the
atmospheric air to promote the combustion of the gases is admitted
through numerous small orifices near the exits from the bags, or in
some cases lower down in the bags, so as to consume the gaseous
inflammable compounds which arise from but are not consumed in the
furnaces. I also combine with such means of burning such gaseous
fuel and preventing smoke the introduction of inlet holes at other points,
as under the floor or in the upcast when the latter passes though the
chamber containing the goods to be burned. In order to complete the
combustion of fuel in the flues employed for distilling or evaporating
purposes I introduce air from the outer atmosphere by inlets arranged
at various points throughout the flue. The particular distribution or
arrangement of these inlets will depend upon the circumstances of each
particular case and the length to which the flames have to be carried.
The flames produced I sometimes allow to escape at the crown, and
sometimes I bring them down through openings in the floor properly

page_text: regulated to secure equality of temperature throughout the oven, or down
through a central flue of suitable capacity to carry off all the gases and
vapours. Where a hovel exists over the oven and the draught is a
descending one I provide the means of making the hovel gather closely
round the chimney if the chimney is central, or I close the hole at the
top if not.
In order to dry the goods in muffle or other ovens with down draught
I make use of the flues under the floor and the downcasts for carrying
heat into the kiln during the smoking process, the downcasts for the
time being serving as upcasts or chimneys. I combine with this the
introduction of warmed air (at the bottom of the muffle) which acts
as a vapour carrier. By this means I am enabled to dry the goods
more quickly and with the application of a lower temperature than
heretofore.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Young Darracott Scott in the Great Seal
Patent Office on the 19th October 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
YOUNG DARRACOTT SCOTT, of Ealing, in the County of Middlesex,
Lieutenant-Colonel Royal Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of April, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Henry Young Darracott Scott, Her
special licence that I, the said Henry Young Darracott Scott, my
executors, administrators, and assigns, or such others as I, the said
Henry Young Darracott Scott, 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 Islands, and Isle
of Man, an Invention for "IMPROVEMENTS IN POTTERY OVENS OR KILNS, AND
GLASS AND OTER FURNACES," upon the condition (amongst others) that.

page_text: I, the said Henry Young Darracott Scott, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of
their hands and seals, should particularly describe and ascertain the
nature of the said Invention, 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 Henry Young Darracott Scott, do
hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the Drawing
hereunto annexed, and to the letters and figures marked thereon
(that is to say) :-
Under the Letters Patent, dated Fifteenth August One thousand eight
hundred and sixty-eight, granted to me for improvements in kilns, I
described a fire-place adapted for the production of gaseous fuel to be
consumed by means of atmospheric air introduced into flues or chambers.
at some distance from the point at which the combustible gases are
generated.
The object of my present Invention is to combine in one fire-place the
means of attaining the end aimed at in the above-named Patent coupled
with a perfect control over the combustion at the fire-place itself, so that
by very simple arrangements the fire may be made to yield at will in
the fire chamber either a very fierce heat with excess of oxygen, or a
deoxydizing flame arising from the presence of more combustible gas
than the atmospheric air present can combine with.
The Invention also enables the operator to obtain such a mixture of
combustible and incombustible gases as may be requisite to produce
any required heat between the limits of the temperature obtainable in
a given fire-place by generating either the extreme quantity of com-
bustible or of incombustible gases which such fire-place can yield.
Moreover, the Invention permits of the beneficial use of slack dust
and other refuse, or small coal.
The means employed to effect the above objects consist of novel
modifications and combinations of features of furnace arrangements
in themselves well known and long used. They are, first, a feeding
hopper a, Fig. 1, having a considerable inclination downwards towards

page_text: the far end of the fire-place, or that which is nearest to the working
chamber; second, inclined fire-bars 6 to which the fuel descends after
it leaves the hopper a; third, a rectangular or horizontal chamber c,
such as is now commonly used in the potteries, and in which the fuel
is retained by a reticulated wall or glut g, Fig. 1, or in some instances
such as is used at the copper smelting works, see g, Fig. 7, where the
depth of the fuel on the fire-bars is required to be considerable, and
the fire is chiefly retained by the masses of slag which collect upon
them. It is to this chamber that the fuel introduced into the hopper
finally descends. With clear burning coal the chamber may be dispensed
with, or be reduced to a minimum, so as to act as a mere ash-pit. In
this case I generally prefer to step down from the bottom of the hopper
to the bars to get a thicker layer of fuel upon them, or I give the bottom
of the hopper a greater angle of inclination (than is given to the bars),
which produces an equivalent effect.
These parts (the hopper, the fire-bars, and the chamber) have,
according to my Invention, the following uses:-The bottom of the
hopper forms a dead plate on which the fuel undergoes a coking process
with the expulsion of hydrocarbons. Under the roof or cover of the
hopper a thin sheet of air is allowed to creep down and mingle with the
hydrocarbons. Both the air and hydrocarbons are carried forward until
they reach the fire-bar section 6 of the furnace. Here they are kindled
wholly or in part and become mingled with the products of combustion
created by the air which penetrates by the fire-bars; by this means any
free oxygen mixed with the flame is raised to a very high temperature,
and coming into contact with the gaseous products of the combustion
(caused by the entry of air through the glut or bars of the chamber c)
creates a fierce heat. Meanwhile the solid green fuel which is thrown
in at the opening of the hopper a is partially or wholly coked when
it reaches the bars b, and before it reaches the bottom of the
chamber c little or nothing but ash remains. To the sole of the
hopper a I give, by preference, an inclination of sixty degrees to seventy
degrees, but with a free running coal not apt to "scaffold" a less angle
will suffice. The rule I follow is to give it a somewhat steeper
inclination than that naturally taken by the coal in its descent when
under the process of distillation (to which it is subjected in the earlier
stages of its consumption), that is, its slipping angle under these con-
ditions. The roof or cover of the hopper should also be inclined to

page_text: the horizon at a considerable angle, or be so formed (see Figures 1, 3,
and 7, at a) as to keep the air current (admitted at or near the feeding
opening) in the directions of the upper surface of the coals in the hopper
or on the fire-bars. It is best, however, that the upper and lower
surfaces should diverge so far as is consistent with thus bringing
the draught of atmospheric air (which increases rapidly in volume as
it descends) tangentially down over the ignited fuel. The sides of the
hopper may also diverge slightly towards the interior of the fire-place
with advantage. The feeding opening may be from five to ten inches
across, according as light or heavy charging is necessary. As soon as
the hopper is freshly charged the fuel draws away from the roof, leaving
room for the admission of larger quantities of atmospheric air, which
is regulated by the tile or cover r. The lower portion of the hopper
acts as a dead plate, and leads on to the bars either with a break, as
in Fig. 7, or without a break, as in Fig. 1. The bars 6 have either the
same inclination as the bottom of the hopper, or nearly so, and lead to
the chamber c. The fire-bars are, however, sometimes omitted, as
shown in Fig. 3. The fire-place then consists of the hopper and
chamber c only, and this is the form that I find to be most suitable
for all ordinary furnace work, such as biscuit ovens, fire-bricks, salt,
glazed and terra cotta ware, evaporating pans, and other analogous pro-
cesses. In this form of fire-place the point of greatest consumption of
the fuel will take place where the draught down the hopper meets the
draught through the glut. The latter takes the shortest route to the
chimney in the direction (e, f, Fig. 3). It conduces greatly to the suc-
cessful working of the fire-place that the depth of fuel (in the direction
to be traversed by the air draught) should be considerable, for otherwise
(without great attention in the stoking) a clean hole will be eaten
through the fuel at this point and give admission to injurious volumes
of cold air. This dimension (e, f, Fig. 3) of least resistance to the air
should not be less than one foot with a very close lying coal, nor less
than two feet with an open burning coal. The upper limit for (e, f)
will depend how far or not it may be desirable that little but com-
bustible gases should be produced from the fire chamber. In some
instances I introduce flues for the introduction of atmospheric air
immediately behind the bridge, as shown in Fig. 3, at o.
For all ordinary ware the crown or roof of the hopper may be formed

page_text: description I sometimes employ purposely made furniture, in which
the roof slab of the hopper is indented with V-shaped or other suitable
corrugations, such corrugations being in the direction of the length
of the hopper when combustion is required to take place wholly or
chiefly in the fire chamber (see Figures 4), and in the transverse
directions when the apparatus requires that gaseous fuel should be solely
or chiefly generated in the fire chamber, to be subsequently consumed
in the flues or working chamber by fresh admission of atmospheric air
at those points (see Figs. 5). The two systems of corrugation may also
be sometimes combined in order to make the admission of air at the
feed opening less dependent on the care of the operator in using his
regulating tile or cover r. In lieu of admitting the air through the
coal chamber of the hopper (or in addition to such means of air supply)
I sometimes perforate its roof slab with one or more rows of numerous
small openings or with long slots h (see Fig. 9); or the roof slab may
be formed with V-shaped corrugations and slits combined, as at Figs. 4.
When none of these expedients are employed (and the roof of the hopper
is formed with a flat slab only) the effect of the corrugations in the
direction of the length of the hopper may be partially secured by
thrusting down a rod at several points between the roof of the hopper
and the fuel therein, so as to make in the coal itself numerous small
inlets for the admission of air whenever the hopper is freshly charged.
If, however, an ordinary kiln is applied with eight or ten fire-places all
such expedients may be dispensed with, the number of the fires tending
to equalization of general results throughout the process.
Fig. 1 is the form best adapted for glost ovens, but Fig. 3 will answer
for the purpose. Figs. 2, 3, and 3 shew the form best adapted for
biscuit ovens, brick making, glazed pipe making, and other analogous
operations, and Figs. 7 and 8 shew the best form for a puddling furnace.
In this case I employ a door m, through which green coal can be thrown
directly over the glowing coke in the chamber c, and can be immediately
rabbled in with it just previous to the moments at which the great heats
with a limited supply of air are necessary. If the coal turns to slags
the slag can be removed at intervals at the bottom of the chamber C,
as is now practised when the draught becomes too much impeded in the
Welsh smelting works.
The arrangements shown in Fig. 7 for the hopper and roof can also
ד

page_text: The second feature of the Invention relates to the mode of bringing
in fresh air from the outer atmosphere into the flues or chambers beyond
the above-described furnaces to consume the combustible gases generated
in them. Fig. 10 shews how this is done in pottery ovens. In this
case I prefer to bring the air through flues in the bags, thereby both
preserving the bags from the intense heat and warming the air before
it issues from the orifices at o¹, o¹. I sometimes also take up the flues
between the bags, or again let them have their exits within the bags.
I also combine with these means for burning the gaseous fuel (generated
by my fire-places) and for preventing smoke the introduction of inlet
holes at other points, as under the floor or in the upcast when the latter
passes through the chamber containing the goods to be burned.
For enamel kilns in connection with the fire-places above described
I introduce a flue for the admission of air in finely divided streams at
some distance from the fires on a similar principle to those described for
pottery ovens.
In slip kilns and for salt and other evaporating pans I arrange for
the production of gaseous fuel, and I introduce the air in finely divided
streams by means of flues (which may with advantage be carried under
the smoke flues) at points situated at various distances from the fires,
so as to prolong the flame from point to point and keep up its tem-
perature sufficiently to allow of the ignition of the unconsumed gases
over the whole length of the flue.
For brick kilns of the description termed clamp kilns I employ fires
calculated to produce a limited proportion of gaseous fuel, which I
carry forward with the fully burned products evolved at the fires in
flues generally constructed of unburned brick, and burn them by the
admission of air in finely divided streams at points dependent on the
horizontal distance to which the flame has to be carried.
In the case of glass furnaces I arrange my fire-places on the complete
combustion system, so as to evolve intense heat around the pots. In
this case the action of the in draught by the hopper reaches its maxi-
mum as compared with the use of my fire-places for evaporating
purposes where the production of fully consumed gases is kept at
the minimum and the production of gaseous fuel is made a maximum.
In order to complete the combustion of fuel in the flues employed
for distilling or evaporating purposes I introduce air from the outer
atmosphere by inlets arranged at various points throughout the flue.

page_text: The particular arrangement or distribution of these inlets will depend
upon the circumstances of each particular case and the length to which
the flames have to be carried, but in cases in which liquids are to be
acted upon and rapid abstraction of heat takes place I sometimes con-
struct a flue in fire-brickwork, or I use specially made fire-clay flues
within the metal flue, which is in immediate contact with fluid. The
fire-brick or fire-clay flue is reticulated to allow the heated gases to act.
on the evaporating trough.
In giving these illustrations of the mode in which I apply my
Invention of fire-places and inlet holes for atmospheric air I am not to
be understood to limit myself to these, the system admitting of extension
to the majority of cases in which heat-generating furnaces are employed
in manufactures.
A third feature of the Invention relates to the smoking of goods which
are to be burned in muffle kilns. In the kilns to which I allude the
draft is taken over the crown of the oven, and then passes through down-
cast chimneys to flues, which circulate beneath the floors to the
chimney. In this arrangement it is very difficult to get up the heat so
as to smoke the goods equably, and to do it properly a long time is
occupied and care is necessary. In this form of kiln I introduce flues
under or through the walls of the kilns to consume the combustible
gases in the fire flues which circulate under the floor, and by this means
I heat the floor equally with other parts of the kiln; or, if these air
flues do not exist, corresponding flues may be made to communicate
from the outer atmosphere with the floor fire flues, which again com-
municate with the downcast from the top of the kiln. In front of these
inlets from the atmosphere I make temporary fire-places, which I light
before I light the fires with which the goods are to be burned, and I
close the chimney draft, but open the top of the downcast flue already
mentioned. The result of this is that the products of combustion take
the easy road to the downcast, and issue from it in the reverse direction
to that which the flames to burn the goods will take. When the flues
are well warmed, and the warmed draft will readily take the direction
through the chimney, I remove the damper from it and I close the
orifice at the top of the downcast. After some time I light the fire all
round the kiln, and the draught taking its usual course is greatly assisted
at the early stages of the process by the warmth given to the flues
beneath the floor by the temporary fires, which are now removed, the

page_text: flues being closed until wanted as air passages to consume the gaseous.
fuel in the flues. I sometimes also introduce into muffle kilns beneath the
ordinary fire-places air flues, which pass through the inner casing and
establish a communication between the outer atmosphere and the
interior of the kiln, which communication can be cut off when the
goods are dry. The air in its passage into the kiln becomes warmed
and acts as a vapour carrier. Openings are of course left in the top.
of the muffle to give vent to the steam from the moist goods in the
usual manner. By the above-described means I am enabled to dry
goods in muffle kilns more quickly, more equably, and at a lower tem-
perature than heretofore.
Having now described my Invention of "Improvements in Pottery
Ovens or Kilns, and Glass and other Furnaces," and having explained
the manner of carrying the same into effect, I claim as the Invention
secured to me by Letters Patent as aforesaid,-
First. The combination and arrangement of parts herein set forth for
constructing the fire-places and consuming or burning the solid and
gaseous fuel in kilns, ovens, and furnaces.
Second. Constructing, combining, and arranging the hopper and fire-
bars and the other contiguous parts of the fire-places as herein set forth,
so that a thin stream or current of air may be admitted above and made
to pass over the surface of the fuel in a direction parallel to the
inclination or angle which the ignited fuel would naturally assume on
the inclined surfaces on which it rests, and which air will thereby be
heated and made to commingle and combine with the gases evolved from
the solid fuel.
Third. The combination of the chamber c with and in continuation of
the fire-bars or hopper for the purpose of containing a thick layer of
fuel, through which a current of air is made to pass in order to produce
a continuous supply of combustible gases.
Fourth. The adaptation to fire-places or flues such as those above
described of inlets or apertures for the admission of atmospheric air for
the combustion of the gaseous fuel (derived from such fire-places) at the
point or points of the flues or working chambers where the heat of com-
bustion is required to operate.
Lastly. I claim the arrangement of parts herein set forth whereby
the goods in muffle kilns may be "smoked" by means of temporary

page_text: additional fire-places and for the admission of warmed air into the kiln,
as and for the purpose herein set forth.
In witness whereof, I, the said Henry Young Darracott Scott, have
hereunto set my hand and seal, the First day of October, in
the year of our Lord One thousand eight hundred and sixty-
nine.
HENRY Y. D. SCOTT. (L.s.)