IMPROVEMENTS IN THE BURNING AND DRYING OF BRICKS, LIME, CEMENT, AND OTHER LIKE SUBSTANCES, IN THE KILNS EMPLOYED THEREIN
Year: 1868

page_text: LETTERS PATENT to Humphrey Chamberlain and John Craven, both
of Wakefield, in the County of York, Engineers, and Hermann
Wedekind, of No. 2, Dunster Court, Mincing Lane, in the City of
London, Engineer, for the Invention of "IMPROVEMENTS IN THE
BURNING AND DRYING OF BRICKS, LIME, CEMENT, AND OTHER LIKE SUBSTANCES,
IN THE KILNS EMPLOYED THEREIN."-Partly a communication
from abroad by Friedrich Hoffmann, of Berlin, in the Kingdom
of Prussia.
Sealed the 23rd June 1868, and dated the 19th March 1868.
PROVISIONAL SPECIFICATION left by the said Humphrey Chamberlain,
John Craven, and Hermann Wedekind at the Office of the Com-
missioners of Patents, with their Petition, on the 19th March 1868.
We, HUMPHREY CHAMBERLAIN and JOHN CRAVEN, both of Wakefield,
in the County of York, Engineers, and HERMANN WEDEKIND, of No. 2,
Dunster Court, Mincing Lane, in the City of London, Engineers, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
THE BURNING AND DRYING OF BRICKS, LIME, CEMENT, AND OTHER LIKE SUBSTANCES
AND IN THE KILNS EMPLOYED THEREIN," partly communicated to us from

page_text: abroad by Friedrich Hoffmann, of Berlin, in the Kingdom of Prussia,
and partly our own Invention, to be as follows, that is to say:-
This Invention relates, firstly, to certain modifications of or improve-
ments in the kilns for burning bricks, lime, cement, and other like
substances, for which Letters Patent were granted to Alfred Vincent
Newton, bearing date the 22nd of December 1859, No. 2918, and to
Humphrey Chamberlain, John Craven, and Hermann Wedekind, bearing
date the 24th of June 1864, No. 1596, and has for its object the
simplification of the construction of the kilns, rendering them more
suitable for contractors and temporary works, whilst at the same time,
as the steam and products of combustion are more rapidly carried off, a
better quality of burned goods is obtained, and greater economy of fuel
is effected.
Secondly. To a mode of drying the bricks in what is known as "Hoff-
mann's kiln," as described in the before-mentioned Patents of December
1859 and June 1864, whereby their color is much improved, and the
construction of steam flues is dispensed with.
Thirdly. To an improved appliance to be used in connection with
the firing holes of what is known as "Hoffmann's kiln," with a view
to preventing when there is a strong draught or too great an inrush
of cold air at the time the firing hole is opened for the introduction
of fresh fuel, and to avoid the inconvenience which sometimes arises
when there is not much draught from the internal pressure of gas
and
rarefied air, causing a puff outwards through the firing hole, thereby
losing heat, and blowing the small fuel into the face of the attendant.
According to the first part of this Invention it is proposed to combine
with kilns constructed on the principles set forth in the Specification
of the Patents herein-before referred to a system of forced combustion,
obtained by the employment of a fan blower or exhauster situate
on the outer or inner circumference or on the top of the burning
chamber of the kiln, and dispensing with the use of the usual chimney
and smoke chamber.
In one modification a stationary fan communicates with a continuous
flue formed round the outer or inner circumference of the kiln, from
which flue passages are formed connecting it with the divisions of the
kiln, such passages being opened or closed by air-tight dampers in the
order required. Air is either forced into the division containing
the cooling bricks or is exhausted from the division containing the

page_text: green bricks, and in either case the draught is caused to circulate
throughout the whole of the divisions, except those which are being
cither emptied or filled.
In another modification we use a portable fan, and dispense entirely
with chimnics, flues, smoke chambers, and valves or dampers, the fan
being simply connected direct with any one of the several divisions
through the ordinary doorway, or through a special opening if preferred,
and is to be removed from time to time to a fresh division as the fire
proceeds. The air may either be forced in behind the fire, in which
case it will pass off through a moveable smoke pipe temporarily fitted
on to the feed holes or man-holes, the position of this smoke pipe being
changed as the fire proceeds; or the air may be exhausted from the
front of the fire if preferred. The heat being wasted for the purpose
of supporting the draught, as is the case with ordinary draught chimnies,
it is obvious that a considerable saving of fuel in this respect will be
effected. Should the air as it leaves the kiln be found to be of an
elevated temperature its heat may be utilized by being forced through
separate drying chambers or flues.
In carrying out the second part of our Invention we place a small
fire-grate over each or any desired number of the firing holes of the
chamber of wet bricks and kindle a fire in cach grate. The down
draught into the kiln draws in a considerable quantity of heat at the
numerous firing holes, and by having air holes beneath and surrounding
the grate cold air is admitted to mix with the hot air, and thus supports
a continuous stream of warm dry air through each fire-hole down
amongst the bricks, whereby they are effectually and rapidly dried off.
According to the third head of our Invention we employ a removeable
metal or fire-clay cone or funnel mouth which has a contracted opening
in the centre, and this cone we place on each or any desired number
of the feed pipes in the section of the kiln which is burning. The
contracted orifice prevents the disadvantages herein-before referred to,
and when the section of the kiln is used for drying the green bricks
the cone may be readily removed to afford a larger inlet for the cold
air which is required during the drying process.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Humphrey Chamberlain, John Craven, and
Hermann Wedekind in the Great Seal Patent Office on the 19th
September 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, HUMPHREY
CHAMBERLAIN and JOHN CRAVEN, both of Wakefield, in the County of
York, Engineers, and HERMANN WEDEKIND, of No. 2, Dunster Court,
Mincing Lane, in the City of London, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of March, in the year of
our Lord One thousand eight hundred and sixty-eight, in the thirty-first
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto us, the said Humphrey Chamberlain, John Craven, and
Hermann Wedekind, Her special license that we, the said Humphrey
Chamberlain, John Craven, and Hermann Wedekind, our executors,
administrators, and assigns, or such others as we, the said Humphrey
Chamberlain, John Craven, and Hermann Wedekind, our executors, ad-
ministrators, or 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 THE
BURNING AND DRYING OF BRICKS, LIME, CEMENT, AND OTHER LIKE SUBSTANCES,
AND IN THE KILNS EMPLOYED THEREIN," partly a communication from abroad
by Friedrich Hoffmann, of Berlin, in the Kingdom of Prussia, and partly
our own Invention, upon the condition (amongst others) that we, the
said Humphrey Chamberlain, John Craven, and Hermann Wedekind,
our executors or administrators, by an instrument in writing under our
hands and seals, or under the hand and seal of one of us, should par-
ticularly 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 we, the said Humphrey Chamberlain, John
Craven, and Hermann Wedekind, 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,

page_text: reference being had to the accompanying Drawings, and to the letters
and figures marked thereon, that is to say :-
Our said Invention relates, firstly, to certain modifications of or
improvements in the kilns now generally known as Hoffmann's con-
tinuous action kilns, for burning bricks, lime, cement, and other like
substances, for which Letters Patent were granted to Alfred Vincent
Newton, bearing date the Twenty-second of December, One thousand
eight hundred and fifty-nine, No. 2918, and to Humphrey Chamberlain,
John Craven, and Hermann Wedekind, bearing date the Twenty-fourth
of June, One thousand eight hundred and sixty-four, No. 1596, and
has for its object the simplification of the construction of the said kilns,
rendering them more suitable for contractors and temporary works,
whilst at the same time, as the steam and products of combustion are
more rapidly carried off, a better quality of burned goods is obtained,
and greater economy of fuel is effected..
Secondly. To an improved mode of drying the bricks in the said
kilns, whereby the color of the bricks is much improved, and the con-
struction of steam flues is dispensed with..
Thirdly. To an improved appliance to be used in connection with the
firing holes of the said kilns, with a view to preventing too great an
inrush of cold air when there is a strong draught on at the time the
firing hole is opened for the introduction of fresh fuel, and to avoid the
inconvenience which sometimes arises when the draught is weak from
the internal pressure of gas and rarefied air, causing a puff outwards
through the firing hole, thereby losing heat, and blowing away or
scattering and wasting the small fuel as it is being introduced..
According to the first part of this Invention it is proposed to combine
with kilns constructed on the principles set forth in the Specifications
of the Patents herein-before referred. to. a system of forced combustion,
obtained by the employment of a fan blower or exhauster situate on
the outer or inner circumference or on the top of the burning chamber
of the kiln, and dispensing with the use of the usual chimney and
smoke chamber...
In one modification a stationary fan communicates with a continuous
flue formed round the outer or inner circumference of the kiln, from
which flue passages are formed connecting it with the divisions of
the kiln, such passages being opened or closed by air-tight dampers in

page_text: the order required. Air is either forced into the division containing the
cooling bricks, or is exhausted from the division containing the green
bricks, and in either case the draught is caused to circulate throughou
the whole of the divisions, except those which are being either emptied
or filled.
In another modification we use a portable fan, and dispense entirely
with chimneys, flues, smoke chambers, and valves or dampers, the fan
being simply connected direct with any one of the several divisions
through the ordinary doorway, or through a special opening if preferred,
and is to be removed from time to time to a fresh division as the fire
proceeds. The air may either be forced in behind the fire, in which
case it will pass off through a moveable smoke pipe temporarily fitted
on to the feed holes or man-holes, the position of this smoke pipe being
changed as the fire proceeds; or the air may be exhausted from the
front of the fire if preferred. The heat being wasted for the purpose
of supporting the draught, as is the case with ordinary draught chimnies,
it is obvious that a considerable saving of fuel in this respect will be
effected. Should the air as it leaves the kiln be found to be of an
clevated temperature its heat may be utilized by being forced through
separate drying chambers, or flues..
In carrying out the second part of our Invention we place a small
fire-grate over each or any desired number of the firing holes of the
chamber of wet bricks, and kindle a fire in each grate. The down
draught into the kiln draws in a considerable quantity of heat at the
numerous firing holes, and by having air holes beneath and surrounding
the grate cold air is admitted to mix with the hot air, and thus supports
a continuous stream of warm dry air through each fire-hole down
amongst the bricks, whereby they are effectually and rapidly dried off.
According to the third head of our Invention we employ a removable
metal or fire-clay cone or funnel mouth, which has a contracted opening
in the centre, and this cone we place on each or any desired number
of the feed pipes in the section of the kiln which is burning. The
contracted orifice prevents the disadvantages herein-before referred to,
and when the section of the kiln is used for drying the green bricks
the cone may be readily removed to afford a larger inlet for the cold
air which is required during the drying process.
And in order that our said Invention may be fully understood we
shall now proceed more particularly to describe the same, and for that

page_text: purpose shall refer to the several Figures on the annexed Sheet of
Drawings, the same letters of reference indicating corresponding parts in
all the corresponding Figures.
Figures 1 and 2 of the Drawings represent sectional diagram plans
on a small scale of a cheap construction of kiln intended to be worked
on the continuous system, and specially adapted for the temporary use
of contractors, or for erection on land containing only a thin seam of
clay. In these modifications the construction of chimnies and smoke
chambers is rendered unnecessary, a forced combustion being maintained
by the aid either of an exhauster or blower.
In Figure 1 A represents the continuous chamber of what is now
generally known as Hoffmann's kiln, which chamber is capable of being
divided into compartments or sections, as in the Hoffmann kiln, by
moveable transverse partitions, as shewn by the radial dotted lines a, a.
Each section of the annular chamber communicates by a branch passage
or flue C, either of brickwork or of metal, as shewn in the diagram,
with one common annular flue D (also constructed either of brickwork
or metal) leading to the exhaust fan E, such fan being permanently
connected with the flue D. Although the flue D and fan E are shewn
on the outer side of the kiln, it is it is obvious that they may be disposed
in the central or internal space F enclosed by the said annular or
continuous chamber, in which case the branch flues C would open from
the inner wall of the chamber. Each branch flue C is, of course,
provided with a damper, in order to guide the draught in the proper
direction. In the arrangement shown at Figure 2 all flues and dampers
are dispensed with, as well as the chimney and smoke chambers. A is
the annular kiln, and E is a portable exhaust fan, which is brought
into connection with the different compartments or sections of the
annular chamber as the burning proceeds. We prefer to make special
openings in the side wall of the kiln for the introduction of the exhaust
pipe, although if desired each of the doors leading into the kiln may
have an opening made therein for that purpose. In both these Figures
G represents a closed partition, and arrows point out the direction of
the draught. The fresh air enters by the openings b, c, and after
passing through the kiln or annular chamber A is drawn through the
exhauster E along with the products of combustion in both arrange-
ments. If the kiln be of small diameter, or the chamber A too short
to completely absorb the heat, arrangements can easily be made for

page_text: causing the heated air to pass through separate drying chambers, or
under a drying floor if desired. In lieu of using a portable or moveable
exhauster, as shown in Figure 2, a moveable blower may be similarly
employed for forcing air into the kiln, the only difference in the mode
of working being that whereas in using an exhauster the connection
should be formed at the last drying compartment, so as to draw the
air entirely through the kiln or annular chamber A, in the case of
the blower the connection therewith should be made just in the rear
of the firing section of the kiln, in order that the air may be forced
through the cooling bricks and become heated on its way to the burning
bricks. If desired the gases may be forced out through some of the
firing holes or man-holes in the roof of the chamber A into a chimney,
which is moved forward as the burning proceeds from one set of holes
to another; or the said gases may be forced through a separate flue
leading to one or more drying chambers for the drying of bricks or
other substances. By reason of the superior control of the draught
which is obtained under the system of forced combustion above described
tho steam may be more rapidly carried off, and consequently the color
of the burnt bricks and be improved. In the continuous actions kilns
above described it is obvious that the current of hot air may be properly
guided or directed through the kiln by placing or stacking the bricks
themself on such a manner inside the annular chamber as to divert
the draught at any desired place in the kiln, but we prefer to use for
that purpose temporary walls or moveable partitions G, as herein-before
described.
Figure 3 represents a vertical section of a small fire-grate which we
propose to place over each or any desired number of the firing holes
in the roof of that part of the annular chamber of Hoffmann's kiln
wherein the wet bricks intended to be dried are deposited. a represents
one of the firing holes in the roof situate above that portion or section
of the kiln which for the time being contains wet bricks; b is the
small fire-grate which we propose to place over the opening a, and in
which a fire is kindled. The down draught into the kiln draws in
with it through the firing holes a a considerable amount of heated air
and gases at numerous points, and as cold air is admitted through side
openings c, c, below and surrounding the grate 6 it mixes with the hot
air, and thus a scries of currents of warm dry air enter through the
roof of the kiln, and by circulating amongst the bricks effect their
rapid drying.

page_text: Figure 4 illustrates the third part of our Invention, under which we
propose to adopt to the top of each of the firing holes a in the kiln arch
a loose or removeable cone or funnel having a contracted mouth,
which cone rests on the top of an iron feed pipe d fitted into the firing.
hole a, as shown in Figures 3 and 4. As the mouth of this conc is
contracted to about one inch only in diameter it considerably diminishes
the volume of cold air, which when a strong draught is on rushes down
the firing hole so soon as the lid or cover e is removed, thereby cooling
the bricks, whilst on the other hand it serves to check the outward puff
of gas and hot air which is liable to take place when by reason of the
draught being weak a pressure of gas accumulates in the annular
chamber of the kiln, thereby involving not only a loss of heat, but a
waste of fuel, and occasioning discomfort by causing the fuel to be
blown up into the eyes of the stoker, as will sometimes occur if the
full size of the firing hole (which is about. six inches. in diameter, bo
retained. As these firing holes, however, sometimes require to be used
as air inlets, as, for example, when they happen to be situate over that
section of the kiln wherein the bricks are drying, they cannot be
permanently contracted, since it is requisite that the full size of orifice
be then used to afford free ingress of air, with a view to the more
effectual drying of the bricks. As the cones b, however, are loose, they
may be readily removed when the holes a are required solely as air
inlets into the section containing fresh bricks. During the intervals
of stoking or supplying fuel the firing holes with their cones are kept
closed by the cap or cover e, which is maintained air-tight, or nearly
so by the said joint f. Hitherto we have employed reduced or powdered
coal as the most suitable fuel with which to supply kilns constructed
and used on what is known as Hoffmann's system, but we propose where
circumstances will permit to employ liquid fuel in lieu of coal, such
liquid fuel consisting of any of the liquid hydrocarbons capable of being
burned as fuel. This liquid fuel is introduced through the firing holes a
in the arch of the continuous chamber drop by drop from reservoirs
suitably placed for the purpose.
Having now described and particularly ascertained the nature of our
said Invention, and the manner in which the same is or may be used or
carried into effect, we would observe in conclusion, that what we consider
to be novel and original, and therefore claim as the Invention secured
to us by the herein-before in part recited Letters Patent is,-

page_text: First. The combination with what are known as Hoffmann's continuous
action kilns of fixed or portable exhausters or blowers for producing
forced combustion in such kilns, and for more rapidly carrying off the
steam and moisture emitted from the materials or substances under
treatment, as herein-before described.
Second. The application and use of fires contained in grates situate
over the mouths of the air inlet apertures of what are known as
Hoffmann's continuous action kilns, as and for the purpose herein-
before described.
Third. The application and use to and in the firing holes of what are
known as Hoffmann's continuous action kilns of moveable contracted
mouth pieces, or inverted hollow truncated cones, as and for the purpose
herein-before described.
In witness whereof, we, the said Hermann Wedekind, on behalf
of myself and the said Humphrey Chamberlain and John
Craven, have to this Specification set my hand and seal, the
18th day of September, One thousand eight hundred and sixty-
eight.
HERMANN WEDEKIND. (L.S.)