A CERTAIN IMPROVED MODE OF APPLY- ING HEAT FROM VARIOUS COMBUSTIBLES TO MANUFACTURING AND OTHER USEFUL PURPOSES
Year: 1843

page_text: DU
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
ROBINS BOOTH, of Hanley, in the County of Stafford, Manufacturer and
Chemist, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Fifteenth day of June, in the sixth year of Her reign, and in
the year of our Lord One thousand eight hundred and forty-three, did; for
Herself, Her heirs and successors, give and grant unto me, the said George
Robins Booth, Her especial licence, full power, sole privilege and authority,
that I, the said George Robins Booth, my executors, administrators, and
assigns, and such others as I, the said George Robins Booth, my executors,
administrators, and assigns, should agree with, and no others, from time to time
and at all times during the term of years therein expressed, should and lawfully
might make, use, exercise, and vend, within England and Wales, and the Town
of Berwick upon Tweed, my Invention of "A CERTAIN IMPROVED MODE OF APPLY-
ING HEAT FROM VARIOUS COMBUSTIBLES TO MANUFACTURING AND OTHER USEFUL
PURPOSES;" in which said Letters Patent is contained a proviso that I, the
said George Robins Booth, shall cause a particular description of the nature of
my said Invention, and in what manner the same is to be performed, to be
enrolled in Her Majesty's High Court of Chancery within six calendar months
next and immediately after the date of the said in part recited Letters Patent,
as in and by the same, reference being thereunto had, will more fully and at
large appear,

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
George Robins Booth, do hereby declare that the nature of 1 my said Invention,
and the manner in which the same is to be performed, is particularly described
and ascertained in and by the Drawings hereto annexed, and the following
explanation thereof (that is to say) :-
My improved mode of applying heat from various combustibles to manu-
facturing and other useful purposes consists principally in a novel and peculiar
construction and arrangement of the hearth or fire-place, flues, chambers, &c. in
which certain combustibles or combination of .combustibles are to be employed
for the purposes of generating heat and the application thereof to useful pur-
poses. The object of my Invention is, firstly, by an improved mode of applying
heat from various combustibles-to effect a saving of fuel in sundry manufactures
and purposes wherein heat is employed. This improved mode consists in the novel
and peculiar construction and arrangement of the parts constituting the hearth or
fire-place, which contains the fuel; this is regulated by the object to which the
heat is to be applied, as herein-after explained; in the mode of using and com-
bining some or all of the various combustibles which are herein-after explained;
in the construction of the chamber or chambers for confining the heat when
envolved from the hearth or fire-place; in the construction of the apertures,
flues, and tubes, for the passage of the heat from the hearths to the said
chamber or chambers; and in the construction of the apertures, flues, and
vents for the final exit of the hot air, smoke, and gases. Such being the nature
and object of my said Invention, I will proceed to describe the means of bring-
ing the same into practical effect'; and for this purpose I have attached to
these presents two sheets of Drawings, exhibiting the entire novel arrange-
ment and peculiar construction of the apparatus constituting my improved
mode of applying heat. In order that this Invention may be made practically
evident, I have selected, for the sake of illustration, its application to the
pottery manufactures, wherein I am enabled to exhibit various modifications
of my Invention, and which I consider will be sufficient to explain its practical
application to all manufacturing and other useful purposes wherein heat is
required, whether it be for drying, evaporating, generating steam, or other use-
fal application of my Invention. The combustibles I use are coke, charcoal,
coal, cannel, peat, or wood, either separately, altogether, or variously combined,
as the nature of the operation may require, and as is herein-after more fully
explained. The hearth, the seat of the actual combustion of the fuel, is
generally constructed (in the pottery manufactures) in the form of a cube,
having the apertures for feeding the fires in most cases made above the hearths,
the fuel being replaced or thrown into it in quantities adapted to the space to

page_text: :
be heated, and to the degree of heat which is required. The atmospheric
air is allowed only to pass through the iron bars or grate forming the
bottom of the hearth, and is not admitted at the sides by any mouth..or
opening; nor over the top of the hearth, except only when a profuse quantity
of inflammable gas shall be found in the chamber; then a portion of atmospheric
air is admitted by opening small "cottle holes," which are made in the sides
of the chamber: At the bottom, and level with the bars; I prefer contracting
the hearth a little, that is to say, in a hearth of two feet square, as much as
three inches in each side or thereabouts, and level with the height of the bars, so
as to hinder the cold' air from escaping up the sides and into the flues or
chambers without passing through the combustibles when in a state of ignition.
The bars used for a cubical four feet hearth and a high heat, are two inches
square, and three of them are sufficient for this purpose: For a lesser degree
of heat, four, six, or eight bars, will be required. The bars used for long con-
tinued heats I.also prefer being doubled and trebled in depth, and placed one
upon another, so that the top tier can be removed at any time, leaving those
below in their places to support the fire, thus affording the opportunity of with-
drawing the melted cinders or slag along with the top bars, and the means of
supplying from below fresh bars to take the place of those which are withdrawn,
and as the occasional removal of the melted cinders or slag may require. The
hearth is built of fire bricks, or of fire clay, or of a mixture of fireproof clay
with other fireproof substances, 'such as sherds, stones, &c., which in this mixed
state. I call "poizee," according to the heat to be applied, and is open or covered
at the top as the purpose may require, as herein-after is moré particularly
shewn. The sides of the hearths are perforated or not, according to the use to
which they are applied; where the greatest heat is required, they are close;
where the last heat is required, they are open. The hearth in all cases is fixed
as near as possible to the substances or things to which the heat is to be applied.
The fuel is supplied to the hearth either over the top thereof, at and above the
sides, or through the bottom of the bars, by a simple regulation of the same as
may be most convenient. The combustibles are regulated according to the
purposes for which they are wanted; coke; èharcoal, coal, cannel, peȧt, 'and
wood may be used, separately or together, or any one with the other, taking
care that when the substances or things to be acted upon are exposed to the
heat in an unprotected state, that regard is paid to the nature of the fuel,
so as not to produce any chemical' effects unsuitable to the process, or inju-
rious to the said substances or things; when, on the other hand, the sub-
stances or things subjected" to heat are protected by casings, or are covered,
then Buch caution is unnecessary, and any or every fuel may be used, the main

page_text: object being to produce a given heat in the most direct and efficient manner;
thus for low temperatures or generally where the space of the oven is small,
simple fuel, as coke and coal, are sufficient. In higher heats, my Invention offers
the best mode of creating powerful heats in the hearth, and for carrying and
making use of that heat through an extended range of space. In these cases I use
fuel of various or mixed kinds; for instance, I create an intense heat in the hearth
itself by the combustion of coke or charcoal; then, by the addition of coal to
one or both of them when in a state of combustion, the heat is extended and
dispersed by the flame to every part of the chamber; but this is done only when
powerful or extended heats are wanted, coke or charcoal or peat being sufficient
for lesser degrees and for an extent of heat over lesser spaces, or for small heats
over large spaces. Secondly, the chambers are the spaces wherein the action
of the heat is applied to the substances or things, in order to produce the effects
desired. They are constructed of various forms, square, round, oblong, or
polygonal, as most applicable to the several uses. They contain the things to
be operated upon by the heat, either in cases or without, and may be technically
termed hot air stoves, chambers, kilns, or ovens. The proportions of the size
which they bear to the hearths are determined by the amount of heat that is
wanted; if it be a great heat, the chamber is less extensive than for a low heat.
The chambers may be covered over with brick arches or with iron coverings, or
with part of each. Where great heat is required, the exterior sides of the
chambers and the outsides of the hearths, also the insides in like manner, when
needed or preferred, may be constructed of wrought or cast iron or of brick, then
lined with bricks, or with fireproof clay, or with fireproof. clay mixed with
other fireproof substances, such as sheards, stone, &c., which I call " poizee;"
and where lesser heat is required, the chambers may be constructed with com-
mon bricks and mortar, or with iron casings, and lined with mortar mixed with
hard substances which I call "poizee." The height, width, and breadth of the
chambers must be suited to the purpose intended. Where a single hearth is
used, I prefer placing it in the centre of the floor of the chamber, below or above
the same, as may best suit the purpose; but where many hearths are required,
then they will have to be placed at proportionate distances from each other. In
many cases there is no necessity for any apertures for the admission of heat in
the chambers, except the open top of the hearth. But where the heat must be
generally diffused through all parts of the chamber and for low temperatures,
then the hearth must have perforations at its sides, and so transmit the heat
through a hollow floor containing numerous apertures in its surface. Where
the hearth is partly covered over, then tubes must be placed over the hearth, and
flues must be constructed from the hearth or from its covering to conduct the

page_text: heat to various apertures made in the floor. The heat in the chambers (in my
present arrangements) is not always permitted to ascend to the top and there to
escape through the chimney or opening, but is drawn downwards through the
aperture and flues which are placed in the sides of the chambers before it makes
its exit. From the ascending principle of heat, most of the articles placed in
large and lofty chambers would be untouched by its action, except in its ascend-
ing course, and except by radiation; according, therefore, to the purpose in view,
and for the degree of heat required and the extent of the chambers, I first
direct the heat towards the top of the chamber, and then make it descend again,
so that in its courses the flame and heat become applied to all objects within
their range. The apertures through which it escapes into the chimnies or vents
are frequently placed at or near the floor of the chambers. Also, by sending the
heat through the small apertures at the end of the flues leading from the hearth,
the heat of the bottom of the chamber is equalized by the heat at the top.
The number and size of the apertures leading into the flues for the exit of hot
air, &c. depend upon the heat required, the dispatch that is wanted, the size of
the hearth, &c., and especially upon the quantity of fuel used therein. For
ordinary purposes in pottery manufactures, the size of the hearth being four
cubic feet, the apertures may be four, six, or eight in number, and four and a half
by four and a half inches each; lesser dimensions than these might not produce
the heat requisite for the plans which I have laid down, whilst more would ocea-
sion a wasteful expenditure. The flues are of similar dimensions to the apertures
leading to them, and are subject to the same regulations; they are placed within
the exterior and interior walls of the chamber, as before mentioned, or on the
outside of the chamber, or within it, as may be preferred; generally they are
only required to be of such height above the top of the chamber as is equal to
the height of the chamber itself, or at most to a hoight equal to the length from
the bottom of the hearth to the top of the chamber within; they may be carried
afterwards in any direction, except upwards, or left open, but in certain cases I
recommend the use of dampers at their tops, the better to regulate the heat,
&c. &c. Sometimes, for the sake of convenience, a number of the flues
may be
collected into one, or into one stack, where such operation will not damage the pro-
cess. Compared with other modes now in use for producing the same effects, my
Invention will produce a great saving in the wear and tear of ovens, and a still
greater saving in the expence of the fuel. Description of the Drawings:-
In Sheet 1 of the Drawings hereto annexed, I shew the application of my Inven-
tion to various departments of the manufacture of china and earthenware, by
way of illustrations; and in Sheet 2 I have exhibited its application to manu-
facturing and other useful purposes. Similar letters of reference are marked

page_text: upon corresponding parts in all the figures, which are drawn on a scale of
about three fourths of an inch to the foot. Figure 1 is a sectional elevation of
& "biscuit óven," or that which is employed for baking the ware in the "bisque"
state; and Figure 2 is a plan view, the section being taken at the line a, b, in
Figure 1. A is the chamber or oven, which may be either round, square, oblong,
or polygonal; B, the hearth; C, the fire bars, one, two, or more deep, accord-
ing to the heat wanted, being two by two inches; D, the ash pit; E, the feeding
door (which is made air-tight) placed above the hearth; F, F, the several flues
leading from the top of the conical covering Q of the hearth, and opening into
the chamber at the aperture; G, G, the apertures on the floor, these apertures
for an oven of this scale are each about one by two inches; H; the floor of the
oven; I, apertures leading from the chamber to the flues, the first four being at
or near the bottom of the chamber, the next four one foot higher up in the wall
of it; J, J, the four flues leading to the vents; K, the four vents; M, a tube
in the centre of the floor of the chamber to carry up the bulk of heat into the upper
region thereof; N, the gas chamber above the oven or chamber, and communi-
eating. with it by a small aperture, where the light gases collected pass through
an exit pipe of one inch or thereabouts; O, the walls of the chamber, built of
"poizee" and cased with brick or iron, as already described; P, the arch or
covering of the chamber, having no aperture through it except the small tube
leading into the gas chamber N. The plan view, Figure 2, shews the floor of
the chamber, the position and sizes of the tubes, flues, apertures, feeding door,
and hearths, which are marked with the same letters of reference. The method
of firing and of making use of the said oven for ware in the "biscuit" or "glost"
state is as follows:-The "saggars" containing the ware are placed in the
chamber in the usual manner of placing them in ordinary ovens, and all parts
of the chamber being made close by building up the door or by clammings, and
by closing up every aperture, except those between the bars and the vents. The
hearth is then filled with coke or charcoal; and is ignited at the top or bottom.
When the combustibles have burnt themselves down about three parts out of
four (which I prefer being done), I then refill the hearth with coke or charcoal,
and suffer it again to burn down as before.. By this time it will be found that
the tube marked M has become more or less red hot; for the future charges of
the fuel I therefore supply coke, as before, cither mixed with some coal, or 'a
-lump or lumps of coal about ten or twenty pounds, or even more, may be put
upon or under the coke. As the heat of the oven increases, the chamber is found
more capable of consuming the smoke, and more coal may be advantageously
used; but if the chamber is full of flame, a sufficiency of coal is already used.
This flame fills the oven, whereby the oven is greatly heated; and wherever this

page_text: flame ceases, which may be known by looking through the "cottle" holes in
the wall, and when the oven does not require a soaking or an annealing heat,
then another lump or lumps of coal must be added, and so on, always observing
that when the fire in the hearth sinks low, a fresh supply of coke must then be
added to sustain the heat in the hearth; and thus the process is continued until
a sufficient heat is obtained. If a greater quantity of coal be used; then much
larger or. more numerous apertures, flues, and vents will have to constructed.
I claim, therefore, the general novel construction and arrangement of the
whole, and the peculiar combination of the hearths, flues, vents, and cham-
bers, forming together an oven for the application of heat in relation to
"biscuit" or "glost" ovens, and all such or similar applications of my
Improvements as are exhibited in the Drawings attached and above de-
scribed; and more particularly as regards the chamber and the arrange-
ment of the whole, thereby allowing the oven to be of any shape, as before
named, either square, oblong, or polygonal; and the application of the substance
I call "poizee;" and with or without a brick or iron lining on the outer side,
and having no aperture at the top for the general ejection of the smoke or
flame, I also claim the apertures or ascending flues and vents at the sides
of my chamber, being within or without the walls of the chambers; and as the
tubes would answer the same end, provided they were placed in any part of the
chamber, being supported from the floor, 'and then passing through the roof of
the chamber, I also claim such arrangement; and in this case, as most con-
ducive to free combustion. I claim the perfect freedom from apertures, flues, or
openings, in all parts of the apparatus, except at the bars and at the top, this
being in, contradistinction to all plans now in use in ovens employed for these
purposes. I also claim the conical concentrating cover Q of the hearth, where-
by the heat is brought to one focal point in the centre of the said cover, from
thence passing off to the flues, and ascending into the chambers through the
tube or apertures above it; and also the use of the ascending tube being placed
in the centre of the hearth, and above it, being placed as a conductor of the
heat towards the top of the chamber, that the course of the heat may again be
directed downwards to the apertures below the top of the said tube. I do not claim
for tubes in the centre of ovens, but only as performing and aiding to perform
a different duty to that which they usually do. I claim also for the smallness
of the size of the tube, which is only six or eight inches diameter within, or
thereabouts, whilst in ordinary "biscuit" or "glost" ovens, the "bag" or tube is
generally about eighteen or twenty-four inches. This tube must be only three
inches or three and a half inches thick for half way up its height, and one inch
for the thickness of the remaining half for "glost" heats, and in order that the

page_text: heat may more easily radiate through, as there is the same required for greater
heats, but a little increase of from about half to one inch, I claim for each in-
crease; whereas tubes that are used in common ovens are of one thickness only.
As regards the bars, I claim for the few in number that are used in this pro-
cess, and the smallness of their dimensions, as well as the mode of placing
them one over another; thereby I am enabled to furnish a fresh supply of bars,
whilst firing the oven. I claim as regards the flues under the floor of the
chamber and above the hearth, for the manner in which they radiate from
the centre of the cone covering of the hearth to the various apertures on
the floor of the chamber; and I claim the position of the apertures on
the floor of the chamber, required only of very small dimensions, say from
about one by two inches, let them be made of any form or subdivided into
parts, any of which plans will answer. I also claim for apertures in the
sides of the chamber for the emission of heat, smoke, and gases, whether they
be placed higher or lower down, since no apertures whatever act in like manner
in the ordinary ovens. And as regards the vents for dissipating the expended
heat, &c. in the atmosphere again, I claim for the same being carried above
the oven, as described, be they higher or lower than described, and for the
same being placed at the sides of the chamber, or if passing through the roof
of the same, and for their isolation one from the other, and for the diminution
in size when compared with the ordinary vents. I claim the small chamber
above the top of the large chamber, and for the small aperture therein. And,
lastly, the use or employment of coke, charcoal, peat, coal, cannel, and wood,
either separately or combined, as being entirely new, as applied to these manu-
factures. Figure 3 represents another modification of my Invention, and ex-
hibits a sectional elevation of a kiln or oven adapted to the process of "harden-
ing on," as it is termed in pottery manufactures, that is, neutralizing the oil
which is used in the process of printing the ware; and Figure 4 is a plan of the
hearth and flues, the section being taken at the line c, d, in Figure 3. The
following is the manner in which my improved mode of directing heat to such
manufacturing purposes is applied. For this purpose the chamber A is also
employed; and as a low heat is only wanted in this process (say the tempera-
ture at which lead melts), either coke, charcoal, or peat are used, or such other
combustible substances as do not emit smoke in combustion. The whole of
the apparatus above the top of the hearth may therefore be dispensed with, which
allows more available room in the chamber or oven, the floor H of which is
provided with apertures L, L, for the passage of the heat from the flues of the
perforated hearth. In this chamber I make use of what I term a "thermo-
lever" to register the heat required, which is exhibited in Figure 3 and found

page_text: very useful. A lever a is placed above the chamber on the outside, having a
rod or wire 6 descending from one end of it, and passing through the arch into
the chamber; to this is attached a ladle c, perforated with holes; this lever is
balanced at the other end and on the outside the chamber with a weight d, and
as the heat rises to that point at which the lead melts, the weight falls, and
indicates that the exact degree of heat required is attained within the kiln or
chamber A. In the hardening-on oven I prefer using a perforated hearth B, B,
having apertures left at its sides towards the top, which pass into a hollow floor,
having numerous apertures therein, so that the heat may be more equally dis-
tributed from the hearth through the whole of the lower parts of the chamber.
Two other flues Z, Z, may be placed in the walls of the chamber, one on the
right hand and the other on the left, with their apertures about the size of the
other apertures, and about eighteen inches from the top of the chamber, to the
vents of which dampers may be affixed, so as to permit the steam arising
from the ware within the chambers more readily to evaporate. The chamber
I fit up with the iron shelves Y, Y, Y, or with baskets or boxes of iron to
contain the ware, and I place an iron door in the front of the chamber, or
the doorway may be made up with brick and coated in the usual mode. The
mode of using the apparatus for this purpose is as follows:-Having filled the
oven in all parts with ware to be hardened on, except over the hearth, for about
three feet high, I place about one pound of lead in the ladle of the thermolever,
and balance the same at the other end; then I place in the hearth about eight
bushels of coke, charcoal, peat, or anthracite coal (or any other combustible
which does not emit smoke in combustion), either separately, combined, or alto-
gether, and having set fire to the same on the top, (I prefer on the top,
although at the bottom it may answer,) I close the door and close the two
extra or short vents Z, Z, within an inch or so. Exactly at the time when
the arm of the thermolever falls on the outside of the chamber (which it will do
when the lead in the ladle is melted), the process of hardening on is completed,
and the dampers on the two extra vents I then close up, and leave the
chamber to cool. The most economical size of the chamber to which the
above fuel is applied, is about seven feet square, and the hearth two feet square;
one aperture in each flue also is sufficient, placed within three inches from the
floor. I claim, as regards this application of my Invention, the whole of the
novel process, apparatus, mode, and combustibles, as employed in the operation;
the whole being a hot air apparatus. I also claim the variation as to the shape
of the chamber, hearth, &c. The manner of applying my Invention to the dry-
ing of "slip" or the first preparation of clay in the pottery manufactures, and for
evaporating brine, sugar, or other similar processes, is as follows:-Having

page_text: made the same disposal of parts as in the kiln for hardening on, see Figure 3,
I place pans in the chamber on shelves, or on rails of iron, or on arches of
brick, to contain or support the articles to be operated upon, as above named,
one above another, leaving such spaces between each as the operator may
require to fill and empty the same.. When these pans are filled, I fill the hearth
or hearths with coke or charcoal, (which hearths in this case do not require to
be perforated), as in the hardening-on kiln, and the iron doors of the entrance
to the chambers are then closed. As requisite to these processes, I make use of
an instrument which I call an "udiometer " shewn detached in Figure 5, as the
heat here required is less than in the process of hardening on. This instrument
consists of a bowl a, filled with water, placed in the chamber, and supported in
the wall; this bowl has a tube 6 from the bottom of it, which is bent horizon-
tally and brought through the wall outside of the chamber, from thence it is
carried upwards a little higher than the bowl within the chamber; into
this tube is placed, at the outside extremity, a floating rod c, which rod
is graduated; and shews the quantity of water evaporated in the bowl within
the chamber by its height and graduated scale. Thus the workman has only
to ascertain how much evaporation is required for his process, and it will give
him a certain rule for directing the same. In Sheet 2, I have represented my
improved mode of applying heat as employed in a more extended range of
manufacturing and useful purposes, such as kilns for various drying opera-
tions connected with manufactures and the arts, and where the articles under
operation are not to be exposed to the direct action of the heat; and lastly,
as applied to the very important purpose of generating steam, for whatever
purpose it may be required. Figure 1 represents a sectional elevation of a drying
kiln, but adapted particularly to the processes of enamelling in the pottery
manufacture, which adaptation completes my exemplary illustration as applied to
this art. Figure 2 is a plan view of the same, the section being taken at the
line a, b, in Figure 1. In the first place, for enamelling kilns, the whole of
the chamber, hearth, and apparatus represented in Figure 1, Sheet 1, may be.
used in part of this process, or it admits of certain modifications, as herein-after
named. The part which is commonly termed the enamelling kiln, and hitherto
made of brick or quarries or other earthen material, is in my improved appa-
ratus made of cast or wrought iron. An iron box or vessel R, R, is made,
corresponding in shape to the chamber A, A, but of lesser dimensions, and.
placed in the chamber, leaving a space between the outside of it and the walls,
which for a kiln of two feet by two feet, and three feet high, should be two
.inches, and having a tube S,.S, entending from the bottom to the top of the
case; and carried up to within a small distance of the top of the chamber (say,

page_text: of a kiln where the. dimensions are above given, four inches distant from the
top). The bottom of this kiln must be placed upon an arch, or quarries or
elevated flues, as may be preferred, but about four, six, or eight inches from the
floor of the chamber, as shewn in the Drawing. A modification of this kiln
may be made as follows:-If the apparatus in the chamber A and all above
the top of the hearth B be removed, then an iron case, having no tube through
it, may be placed over the hearth, leaving a space of one foot between it and
the top of the hearth, with an earthen floor under the iron case, as in the last
instance, and by placing or fixing up against the side of the iron kiln some
earthen screens to protect them for some distance up the sides from the powerful
heat to which it is exposed in these parts, we have another mode. of fitting
up an enamelling kiln suited to my improved method of applying heat. But
as in this last case the heat passes only up the sides and at the back of the
vessel R, and direct to and over, the top of the kiln, I close the apertures I, I,
at the bottom of the flues in the walls of the chamber, and remove the exit
pipe from the gas chamber, and make an opening there six inches square. I
erect a flue six inches square, equalling or thereabouts the height of the depth
of the iron case or of the chamber A, as before noticed (the size of this flue
being suited only to the dimensions of the kiln before quoted). Again, a third
modification of my improved mode of applying heat to enamelling kilns may be
employed, varying from either of the two former ones, and which I prefer in
some cases, since it offers a greater saving of fuel than either of the afore-men-
tioned plans. Having made an iron case for the chamber A, as before described,
with a larger iron tube, either square or round, in the centre of the case (because
it has now to perform the purpose of a hearth), and having placed the bars of the
hearth directly under this tube, as shewn in Figure 1, Sheet 2, closing it in on
every side about the bars, so as to make the space between the bottom of the
iron case or kiln and the bottom of my chamber tight (for the case or kiln in
this plan is elevated four or six inches from the floor), to permit the heat to
pass under it, and to heat it therein, and from its radiating influence when it
arrives at the apertures I, I, only such brickwork need to be placed under the
case in this instance as is sufficient to support it, I then line or coat the tube
through the iron case either with bricks or with fire clay all the way up the tube,
but decreasing and giving it a thinner coating towards the top, and, this I use
instead of the tube S, if I intend to do away with it, but the tube S will answer
well when it is not of too great a thickness. Or, as follows: I make a tube of
iron, of the width or nearly so of the tube within the chamber, rather conical in
its shape, and place it with its apex end downwards in the tube of the iron

page_text: casing, thus producing a small space between this case and the tube, except at
or near the top; the tube S having been removed, I make in this instance the
inner tube to serve the purpose of a hearth, which being supplied with fuel
from the top, and resting on the bars, the heat ascends up the tube, and is
reverberated over the top of the iron case, and proceeds down the sides of the
walls of the chamber to the apertures and flues, acting upon the ware
placed within the iron kilns in the most pure, certain, and effectual manner.
The mode of using these enamelling kilns is as follows:-For the first and
second plan named herein, I use coke or charcoal, or anthracite coal; this is
placed in the hearth, and I prefer lighting it at the bottom, observing the usual
practice of lighting a small fire in my hearth whilst the workman is charging his
kiln with ware. For an enamelling kiln of larger dimensions, a little coal may
bo advantageously used when the operation is drawing to a close; but wood is
preferable where a high heat is wanted. When the ware is fired-up, the bars
may be withdrawn in case there is much fire in the hearth, or the door above
the hearth may be opened if there is but little; a fresh supply of coke, &c. can
be added at any time during the process, should the size of the kiln require it.
With respect to this particular or any similar application of my improved mode
of applying heat, I claim for enamelling kilns all parts of the apparatus named,
specified, and claimed under all other applications herein-before named, which
are applied to this purpose, more particularly the narrowness of the space
between the interior kiln and the external chamber, the tube passing through
the enamel kiln, the bottom of the enamelling kiln being set direct over the
hearth; and also for using the hearth on one side of the enamelling kiln, should
the same be preferred. I claim also under this head the smallness of the
dimensions of my chimney when compared with the ordinary chimneys in use
for such purposes, and for fixing the same in the centre over the top of the
kiln; or if more than one, for the same being placed in a line transversely across
the centre of the kiln. I claim the conical tube in the enamel kiln and the
bars of the hearth being placed directly under the kiln, having the fire hearth
without or within the kiln, and the hearth immediately below the kiln, and
for lining or coating of the said tube with firo clay in manner therein specified,
and for the conical casing of iron and the mode of using it therein. I also
claim as new the arrangement whereby the hearth is fed with fuel from the
top of the kiln or through the bars, and for the door of the hearth being
placed at the top of the kiln. As my Invention has introduced the use of coke
for the first time for enamelling kiln purposes, I claim its sole use for those
purposes; in like manner I claim the sole use of coke in hardening on, and in

page_text: all other purposes which are specified and named in these applications, the
whole being a new adaptation of this combustible to these useful purposes.
Lastly, I claim the sole right of applying these kilns, &c., as herein described,
to the process of hardening on, should the same kilns be preferred to the
common ones, or for more delicate colors, and for thus introducing iron kilns
for hardening on, which is quite new as applied to such purposes. Figure 8
represents a sectional elevation, exhibiting the application of my improved
mode of applying heat to the generation of steam; and Figure 4, a plan of
the same, the section being taken at the line c, d, Figure 3.
It will be at once seen that the mode of applying my Invention to enamelling
kilns supplies data for applying it to steam boilers, for if, instead of having a
moveable iron door to the internal iron chambers R, R, or kilns, the door
place is made up like the other sides of the kiln, by this simple modification
it is converted into a boiler, so that it is merely transferring the application to
another purpose, where the use is more extensive and advantageous. Thus, for
a large boiler, I have only to increase the number of hearths, either under the
boiler or within it; but by numerous hearths more fuel is saved, and this points
out the necessity for small hearths. This plan is admirably adapted for boilers
used for marine engines, whilst for land engines other advantages present
themselves, arising from the peculiarity of the construction, the importance
of which is shewn by the almost immediate contact of the water with the
fire. I therefore have many small hearths, and thereby increase the contiguity
of the water with the fire, and thus save fuel. To the tube S in the interior
of the kiln (or boiler) various basins or vessels T, T, are attached one above
the other, the bottom of the upper one descending into the lower basin, and
each having receding sides so as to be broader at the top than at the bottom,
and none of them extending so far in their range as the sides of the boiler.
I obtain by these means so many evaporating surfaces (besides the bottom of
the boiler) cach giving off large volumes of steam from the water, which is
thus in immediate contact with the heat ascending the tube S; added to this,
the influence of the reverberating heat in its course from the tube to the aper-
tures and flues, also acts upon the evaporating surface. In this application I
change the brick or "poizee" walls of the chamber for similar cases made of
iron, and thus collect all the heat for the purpose of generating steam, so that no
heat whatever is wasted or abstracted by any surrounding matter, as in the
construction of common hearths for boilers, or by the exit of the heat in the
chimney. The pipe for the entrance of water is shewn at U, and for the
exit of steam at V. As much less heat is required for generating steam than

page_text: for enamel firing, less fuel or lesser hearths or lesser vents will be required.
In whatever the use of the enamelling kiln differs from the steam boilers
when compared with the uses to which a boiler is applied, will be apparent
to all persons of scientific knowledge and mechanical experience. The
tube S, for instance, may be decreased in thickness to be supplied by the
iron casing already described, inasmuch as equalization of heat is not so
much required in this case as in others, because we only want to preserve the
boiler from the excessive action of the heat (so as to prevent any injury to its
texture) thus protecting the iron casing and obviating the necessity for the
constant repairs which usually take place in the boilers, as the inner casing of
the tubo only would need repairs. Still further to promote the economization
of, heat, I place dampers upon all the vents when these improvements are
applied to boilers for the generation of steam, which prevent a wasteful
expenditure of fuel when the steam is up. As regards the mode of using
the boilers, the same kind of fuel. may be used as in the case of enamel kilns;
but I prefer using a coke fire in the hearths. But when there are reasons for
using coal or slack, I recommend that a portion of coke be used as the best
means of making a more perfect combustion, similar to the plan mentioned
with regard to the "biscuit" ovens; and as boilers require a steady continuous
heat, a slight attention to the proportion and quantities of the fuel will easily
point out its connection with the size of the boiler and cylinder. With reference
to this application of my improved mode of applying heat, I claim for the
general use of coke and of coal jointly, or for combustibles producing inflam-
mable gases being mixed or used at the same time with combustibles not pro-
ducing inflammable gases, which this mode of creating heat has pointed out as
of practical utility in the hearths of common boilers, and especially in some
of these constructions. I claim for all parts of my apparatus as specified,
named, or claimed under all other applications herein-before specified and
named, and now described and shewn as applied to this purpose, that is,
whether for land or marine services, and whether the one or the other be used
for either purpose, as particularized in my Specification, for the tubes in the
boilers, the hearths under or in them, the basins surrounding the tubes,
whether the said basins be round, square; or of any other form. I also claim
making the "poizee" walls of the chamber into hollow vessels (of iron) for
containing water, and thus generating steam. I claim for the lesser thickness
of the tube S in this case than in its other applications, and for the mode of
constructing and making the tube, and for using casings within the hearths
when the said hearths are within the boilers, of whatsoever material they may

page_text: be made; and for the use of dampers upon the vents or chimnies, and for the
particular construction of the vents. And, lastly, I claim all other arrange-
ments and constructions of the apparatus above set forth and exhibited in the
Drawings attached as new mode of applying heat for generation of steam.
In witness whereof, I, the said George Robins Booth, have hereunto
set my hand and seal, this Twelfth day of December, in the year of
our Lord One thousand eight hundred and forty-threc.