IMPROVEMENTS IN THE MANUFACTURE OF PORTLAND AND 4.9 PROVISIONAL SPECIFICATION CEMENTS, AND IN THE FURNACES AND APPARATUS EMPLOYED THEREIN
Year: 1871

page_text: LETTERS PATENT to Frederick Joseph Bramwell, of No. 37, Great
George Street, Westminster, in the County of Middlesex, for the
Invention of " IMPROVEMENTS IN THE MANUFACTURE OF PORTLAND AND
4.9
PROVISIONAL SPECIFICATION left by the said Frederick Joseph
Bramwell at the Office of the Commissioners of Patents, with his
Petition, on the 13th March 1871.
I, FREDERICK JOSEPH BRAMWELL, of No. 37, Great George Street,
Westminster, in the County of Middlesex, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF PORTLAND
AND OTHER CEMENTS, AND IN THE FURNACES AND APPARATUS EMPLOYED THEREIN,"
to be as follows:-
Heretofore it has been and at present it is the ordinary practice to
employ in the burning of Portland and other cements, furnaces or kilns
similar to those commonly used for the burning of lime, and to conduct
the operation in one of the two ways known, respectively as "periodical "
and as "running. But in whichever of these two ways the kilns may
be used the operation is subject to a serious defect, because the fuel
"

page_text: carbonic acid generated by the combustion of the fuel, or at least such
part of the fuel as is reached by the air which comes in from the bottom
of the kiln, come in contact with the fuel in the upper part of the kiln
while heated, and thus convert a large portion of that fuel into carbonic
oxide, which rises through the upper portion of the kiln until it meets
with the atmosphere, when it burns on the top of the kiln in such
manner that a large proportion of the heat evolved by its combustion
is wasted.
Now my Invention has for its object the economizing of the fuel by
so constructing the kilns and by so arranging the mode of burning
that the whole or the greater part of the carbonic acid produced in
the kiln shall pass off without acting on the fuel, and this I accomplish
by some one of the following described means or by analogous means:
The fuel may be gaseous, liquid, or solid in the ordinary form of coal,
coke, culm, breeze, wood, or turf, or it may be in the state of powdered
fuel. I construct a vertical kiln with a charging opening at or near the
top and with a draw-off opening at or near the bottom; into this kiln
at a suitable distance above the draw-off opening I introduce the fuel,
and I supply such fuel with air which by preference has been heated
by being passed through amongst the cement which had been just
previously burnt, which cement is on its way from the part of the kiln
where it had been burnt to the draw-off opening, and I allow the pro-
ducts of combustion to pass off through between the portions of cement
which are descending towards the place where the fuel is in combustion
in the kiln so as to give up their heat or a part of it to the unburnt
cement without meeting with fuel on which they could act to convert it
partially into carbonic oxide, and in the same way, I allow the carbonic
acid evolved from the raw cement to pass off without meeting with
fuel on which it could act to convert any portion of it into carbonic
acid. I prefer to withdraw the burnt cement from the lower part of the
kiln continuously or nearly so, so as to obtain the greatest uniformity
of action, but it may be withdrawn intermittently. The charging also
and with a like object I prefer to perform continuously, or nearly so,
but it may be done intermittently. I attain the same end in respect
of keeping the carbonic acid gases clear of the fuel by placing the

page_text: material to be burnt in a horizontal kiln having a travelling bottom
so that the material is carried to and then away from the place of
admission of the fuel. This travelling I prefer to be continuous, but
it may be intermittent. The kiln may be circular or of some other
continuous figure, or it may be one in which the travelling floor may
be in sections and the sections may be taken away at the delivery end
of the kiln and returned at the feeding end, the kiln being in a
straight line or a some other non-continuous form. When I introduce
solid unpowdered fuel into a vertical kiln I pass in just prior to the
introduction of the fuel and above the place where it is to be put in
a set of bars by which I am enabled to temporarily uphold the unburnt
cement while I draw off a portion of burnt cement from the bottom,
thereby lowering the body of burnt cement in the kiln so as to leave a
sufficient space for the introduction of the fuel. After it is placed in the
kiln the bars are withdrawn and the cement is allowed to settle down.
on the fuel. The bars may be worked by bydraulic or other well-
known machinery and may be made hollow so as to be kept cool by a
circulation of air or water.
Another but not so good a mode of carrying out my Invention consists
in introducing the hot products of combustion from fuel consumed in
a separate chamber.
If it be desired to intensify the heat I divert the whole or a portion
of the products of combustion from passing through between the cement
about to come within the action of the fire and I cause the whole or
a portion so diverted to pass through Siemens' "regenerators.”
When I use gaseous fuel I prefer to employ carbonic oxide obtained
from a Siemens' " producer.
"
The gas or other fuel and the air may be forced into the kilns by.
natural draught, by fans, steam blasts, or other well known means or
may be caused to pass in by exhaustion.
To dry the materials or " slip "I employ a chamber with a travelling
apparatus so that the "slip" in being dried gradually approaches
nearer and nearer to the hottest part of the chamber, and I put the
slip" into trays having divisions so that when the slip is dried it, on
removal from the trays, will be found in pieces of uniform size.
66

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frederick Joseph Bramwell in the Great Scal
Patent Office, on the 13th September 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
JOSEPH BRAMWELL, of No. 37, Great George Street, Westminster, in
the County of Middlesex, send greeting..
'
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirteenth day of March, in the
year of our Lord One thousand eight hundred and seventy-one, in the
thirty-fourth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Frederick Joseph Bramwell,
Her special license that I, the said Frederick Joseph Bramwell, my
executors, administrators, and assigns, or such others as I, the said
Frederick Joseph Bramwell, my executors, adminstrators, 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 THE MANUFACTURE OF PORTLAND AND OTHER
CEMENTS, AND IN THE FURNACES AND APPARATUS EMPLOYED THEREIN,"
upon the
condition (amongst others) that I, the said Frederick Josepli Bramwell,
my exccutors or administrators, 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
Scal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Frederick Joseph Bramwell, 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, that is to say.
Heretofore it has been and at present it is the ordinary practice to
employ in the burning of Portland and other cements furnaces or
kilns similar to those commonly used for the burning of lime, and to
conduct the operations in one of the two ways known respectively as
periodical" and as "running." But in whichever of these two ways
66

page_text: the kilns may be used the operation is subject to a serious defect, because
the fuel is mixed throughout the mass of the material to be "burnt,"
and the operations are conducted in such a manner that of necessity the
carbonic acid evolved from the carbonate of lime in the raw cement, and
also the carbonic acid generated by the combustion of the fuel, or at
least such part of the fuel as is reached by the air which comes in from
the bottom of the kiln, come in contact with the fuel in the upper part
of the kiln while heated, and thus convert a large portion of that fuel
into carbonic oxide, which rises through the upper portion of the kiln
until it meets with the atmosphere, when it burns on the top of the
kiln in such manner that a large proportion of the heat evolved by its
combustion is wasted.
Now my Invention has for its object the economizing of the fuel by
so constructing the kilns and by so arranging the mode of burning that
the whole or the greater part of the carbonic acid produced in the kiln
shall pass off without acting on the fuel, and this I accomplish by some
one of the following described means, or by analagous means:-The fuel
may be gaseous, liquid, or solid in the ordinary form of coal, coke, culm,
breeze, wood, or turf, or it may be in the state of powdered fuel. I
construct a vertical kiln with a charging opening at or near the top,
and with a draw-off opening at or near the bottom. Into this kiln, at a
suitable distance above the draw-off opening, I introduce the fuel, and
I supply such fuel with air which by preference has been heated by
being passed through amongst the cement which had been just pre-
viously burnt, which cement is on its way from the part of the kiln where
it had been burnt to the draw-off opening, and I allow the products of
combustion to pass off through between the portions of cement which are
descending towards the place where the fuel is in combustion in the
kiln, so as to give up their heat or a part of it to the unburnt cement
without meeting with fuel on which they could act to convert it partially
into carbonic oxide, and in the same way I allow the carbonic acid
evolved from the raw cement to pass off without meeting with fuel on
which it could act to convert any portion of it into carbonic oxide. I
prefer to withdraw the burnt cement from the lower part of the kiln
continuously, or nearly so, so as to obtain the greatest uniformity of
action, but it may be withdrawn intermittently. The charging also, and
with a like object, I prefer to perform continuously, or nearly so, but
it may be done intermittently. I attain the same end, in respect of

page_text: keeping the carbonic acid gases clear of the fuel, by placing the material
to be burnt in a horizontal kiln having a travelling bottom, so that the
material is carried to and then away from the place of admission of
the fuel. This travelling I prefer to be continuous, but it may be
intermittent. The kiln may be circular or of some other continuous
figure, or it may be one in which the travelling floor may be in sections,
and the sections may be taken away at the delivery end of the kiln and
returned at the feeding end, the kiln being in a straight line, or of some
other non-continuous form.
When I introduce solid unpowdered fuel into a vertical kiln I pass in
just prior to the introduction of the fuel and above the place where it is
to be put in a set of bars, by which I am enabled to temporarily uphold
the unburnt cement while I draw off a portion of burnt cement from the
bottom, thereby lowering the body of burnt cement in the kiln so as to
leave a sufficient space for the introduction of the fuel. After it is
placed in the kiln the bars are withdrawn, and the cement is allowed to
settle down on the fuel. The bars may be worked by hydraulic or other
well known machinery, and may be made hollow, so as to be kept cool
by a circulation of air or water.
If it be desired to intensify the heat I divert the whole or a portion of
the products of combustion from passing through between the cement
about to come within the action of the fire. And I cause the whole or a
portion so diverted to pass through “Siemens' regenerators."
When I use gaseous fuel I prefer to employ carbonic oxide obtained
from a Siemens producer."
"
.
The gas or other fuel and the air may be forced into the kilns by
natural draught, by fans, steam blasts, or other well known means, or
may be caused to pass in by exhaustion.
66
To dry the materials or slip "I employ a chamber with a travelling
apparatus, so that the "slip" in being dried gradually approaches nearer
and nearer to the hottest part of the chamber; and I put the "slip"
into trays having divisions, so that when the "slip" is dried it, on
removal from the trays, will be found in pieces of uniform size.
Having now stated generally the nature of my Invention, I will
proceed to illustrate how it may be carried into practical effect, reference
being made to the accompanying Sheets of Drawings and to the letters
and figures marked thereon.

page_text: Sheet 1 shews a vertical furnace or kiln arranged according to my
Invention to burn cement by the use of gaseous fuel.
Figure 1 represents a side elevation (the left-hand portion of the
Figure being in section), and Figure 2 a sectional end elevation taken
on the line X, X, Figure 1, of such a furnace or kiln.
a, a, a, a, are the external walls, and b, b, are internal cross walls
dividing the kiln into a number of distinct narrow chambers.
c, c, is a
flue or channel for the gas, which gas I prefer to be carbonic oxide or
such as is generated as is now well understood by a "Siemens' producer:"
The inlet or inlets into the flué c for the gas may be in any convenient
position, and are not shewn on the Drawing. d, d, d, are subsidiary gas
channels made in the end and in the partition walls to convey the gas
from the main channel c to the gas openings e, e; from which openings
the gas issues into the various chambers of the kiln. The gas is
regulated to each of the subsidiary channels by dampers f. f. g,.y, are
other channels placed lower down in the end walls and in the division.
walls, and into these the air is admitted by the openings h, h, regulated
by the dampers i, i, and issues into the chambers of the kiln by the
openings j, j. k, k, are spaces in the partition walls, which, by means of
openings 7, 1, communicate with the outer air; the object of such spaces
is to prevent the interior walls from being overheated. m, m, are webs
of endless chains placed below the hopper bottoms of the kilns, which
chains are by preference kept continuously in slow motion by means of
the shafts n worked by the worm wheel and pinion o, o, or by other
suitable gearing, and driven by a donkey engine or other suitable power;
pare waggons, into which the travelling chains deliver the burnt
cement; q is a charging stage, from which the furnace or kiln may
be charged by hand, or preferentially it may be fed continuously by
elevators.
Assuming the furnace or kiln to be in its ordinary working state the
action of it is as follows:-The gas issuing from the openings e, e, per-
meates the narrow body of cement within a chamber and at the same
time comes in contact with the air which has issued by the openings j, j.
This air has risen through the heated cement which had been just
previously burnt, and in that way has cooled down the cement and
become itself highly heated and thus fitted to produce ready and intense
combustion of the gas. The products of combustion pass up through

page_text: the down coming cement and give up heat to it, thus rendering it very
fit to be acted on by the flame.
The furnace or kiln shewn on the Drawing has five chambers, but
obviously their number may be increased or diminished at will. The
partition walls are also represented as extending up to the top of the
kiln, but they might be made to cease a short distance above the gas
channels d, d.
In Sheet 2 Figure 1 is a plan, and Figure 2 is an enlarged transverse
section of another kiln constructed according to my Invention. These
Figures represent an annular kiln circular in plan. a, a, are the side
walls supporting the covering arch b; c, c, is a travelling bottom carried
on wheels d, d, which run on the rails e, e. The bottom is made to travel
preferentially continuously (but it may be intermittently) by means of
the pinions ff, which gear into the rack g. These pinions are worked
by the shaft and wheels h, h, and the whole system is driven by means
of the shaft i from any suitable source of power. The gas is by means
of a suitable flue with regulating valves or dampers introduced into the
two vertical chambers j, j, and permeates the blocks of cement stacked
on the travelling bottom c, c. The bottom is supposed in this instance
to travel "with the sun," as shewn by the full arrow. k, k, represent
two vertical flues which are connected to a chimney. The flues or the
chimney are provided with dampers. The chimney may be built imme-
diately over the kiln or in any suitable place. represents a chamber in
which are the workmen who stack the raw cement on the travelling
bottom; m, m, are the rails on which n the waggon containing the raw
cement is carried; o is an outer and o¹ an inner door constituting an
"air lock," so that the waggons of cement and the workmen can be got
in and out of the chamber without an inrush of air taking place and
spoiling the draft; p is a partition wall which is made to nearly touch
the travelling bottom so as to prevent a large influx of air from that
direction; q is the taking off opening; it is at this place the burnt cement
is removed into the waggon". By preference I apply to this opening a
chamber with "air locks" similar to the chamber but fitted with an
air opening having a regulator to control the quantity of air admitted.
The air to support the combustion of the gases enters at q, and, as shewn
by the dotted arrow, travels to the chimney in a direction contrary to
that of the motion of the travelling bottom, or in this instance “against
k

page_text: the sun."
s is a sand joint to prevent air from getting in between the
travelling bottom and the sides of the kiln.
Assuming the kiln to be in its ordinary working state, the action of it
is as follows: The gas entering at the vertical chambers j, j, permeates
between the blocks of cement, and at the same time finds itself in
contact with the air which has entered at the opening q, and has passed
through the cement previously burnt, thus cooling down the cement,
and becoming itself highly heated, so as to be fitted to enter into ready
and intense combustion with the gas. The products of combustion on
their way to the chimney pass through the cement which is about to
be burnt, and give up heat to it, thus rendering it very fit to be acted
on by the flame. I prefer to make this description of kiln circular, as
shewn, but it may be convenient occasionally to make it of an oval or
other continuous form, not a circle. In such case the travelling bottom
must be made in short sections, by preference connected one to another
by articulations, and provided with plates to lap over, so as to prevent
a large indraft of air if the air have access to the part of the chamber
below the travelling bottom, but if this lower part be made nearly air-
tight, then such covering plates may be dispensed with in the case of
the articulated bottom of an irregular form of kiln, and the sand joint
may be dispensed with in the circular kiln shewn.
°
My improvement in burning cement may also be carried out in kilns
which are not of a continuous form. In such cases the travelling
bottom should be in separate portions, which may be detached one
from another, so that when the burnt cement arrives at one end of
the kiln the portion of the bottom on which it rests may be removed
and returned to the opposite or feeding end by running it on rails
external to the kiln, or two such kilns may be placed side by side, so
that the feeding end of the one shall be near to the delivery end of the
other, and thus the detached portions of the travelling bottom of the one
kiln may be made to return through the other kiln.
In the kiln shewn on the Drawings the gas and air are assumed to
be put into motion by the natural draft of the kiln and chimney, and
further, as regards the gas by the pressure generated in a "Siemens'
producer," as is well understood; but it may be desirable to give greater
energy to the currents of gas and air, so as to cause them to permeate
more readily the body of cement. Under these circumstances the
current may be increased by a fan blast or exhaust, or by a steam jet.

page_text: Should it be for any purpose desirable to obtain a higher heat than
can be got from the arrangements previously described, I make the
following alteration in the kilns. I cause the chimney or other draft
or blast to make the products of combustion traverse across the moving
body of cement, and to pass into a "Siemens' regenerator," which I
employ to heat up the gas or the air, as is well understood. If I
employ it to heat the gas, then I allow the air to traverse, as previously
described, along the burnt cement, and in a direction opposite to its
course, so as to take up the heat from it. If I employ the regenerator
to heat the air, then I let the gas traverse the burnt cement to take up
its heat from it, or I may use the regenerator to heat the whole of the
gas and a part of the air, or the whole of the air and a part of the gas,
letting the remainder of the air or gas, as the case may be, traverse the
cement to take up the heat from it.
As an illustration of my meaning I will refer to Figure 1 of Sheet 2.
If I desire to use such a kiln with regenerators I should suppress the
chimney and flue k and I should make one of the vertical openings j
to communicate with one of the pair of regenerators and the other with
the other, and should thus cause the heated gas or the heated air, or
the gas and a portion of the air, or the air and a portion of the gas
to traverse across the line of cement to be burnt while the whole of the
air, or of the gas, or a portion of the air, or a portion of the gas, as the
case might be, should enter near the opening qand should traverse along
the burnt cement so as to take up the heat from it.
Figure 3, Sheet 2, shews a method of carrying out my Invention when
solid fuel is used. It represents a transverse sectional elevation of a
furnace or kiln. a, a, are the walls; b, is one of a series of bars attached
to c, a plunger of an hydraulic apparatus, by which it can be made at
will to advance across the kiln from right to left, as shewn, or can be
withdrawn from left to right; d, d, are air flues; e, e, are openings for
the admission of fuel. Assuming the furnace or kiln to be in its
ordinary working state (in which condition the bars are withdrawn
from out of the furnace or kiln) the action of it is as follows. A layer
of burning fuel would be at ff, which is supplied with air that has
risen through the burnt cement from the air flues d, d, and has thus
become heated. The flame and heat from this layer of fuel in combustion
rise through the cement above and burn the lower part of it, while the
products of combustion pass up through the upper part and give up heat

page_text: to the raw cement. When the charge of fuel at f, f, is becoming
exhausted the attendant forces forward the bars across the kiln so as
to uphold the cement, then a portion of the finished cement is drawn
off from the bottom of the kiln; this lowers the general body so as to
leave a space below the bars b, b, into which fresh fuel can be introduced.
When this is done the bars are withdrawn and the operation of
burning is repeated. The bars & may be made hollow and may be
provided with a water circulation to prevent them from being injured
by the cat. Screws, racks, and pinions, or other well known and con-
venient means may be employed in lieu of the hydraulic apparatus
to work the bars b, or the bars may be made of a screw form so as to
screw their way in through the cement. In lieu of thus introducing
solid fuel in its ordinary condition, powdered fuel may be introduced
by suitable jets, or liquid fuel may be thus introduced, under these
circumstances the bars b would not be required, and the drawing off
and feeding might be continuous.
Although the furnaces or kilns have been spoken of as vertical and
horizontal it is obvious they might (although not so conveniently) be
inclined and also that in one and the same furnace or kiln part of it
might be so constructed that the cement would move through it by
the action of gravity and part so that mechanical means, as in the
nature of a travelling bottom, must be employed to move the cement.
In order to obtain uniformity of result in burning cement it is most
desirable the pieces of raw cement should be nearly uniform in size, and
that they should be of forms suitable for stacking.
Under the present system of drying the wet "slip" is laid on plates
which form the floors or covers of flues, along which the waste heat
from kilns or the heat of fires specially provided pass. In this way
after a time the whole "slip" is at last dried and then is shovelled
out in pieces of various sizes; moreover the drying is attended with
a great loss of time and heat, because that which is first dried cannot be
removed until the whole of the "slip" is sufficiently dried.
Figures 4, 5, and 6, Sheet 2, shew my improvement in this process
of drying. a is the drying chamber; at the right-hand end is b, a flue
through which the waste heat from a burning kiln or the products of
combustion from a special furnace, or a gas flame, enters and traverses
the chamber towards the left-hand end, as shewn by the dotted arrow,

page_text: a
and makes its escape up the chimney c, or into a flue connected with
a chimney, the flue or chimney being provided with a damper; d is an
endless chain carrying trays e, e. This chain is kept in slow continuous
or in intermittent motion, and traverses, as shewn by the full arrow, in
direction opposite to that of the current of the products of combustion.
The trays e, as shewn at Figures 5 and 6, are made with partitions, and
into the spaces between these the wet "slip" is put; the trays thus
charged are placed on the chain at f, and as they pass through the
chamber a their contents are dried, so that when the trays arrive at the
end they may be removed by the attendant, and turned over so as to
deliver the dried cement in the form of bricks; the spaces into which
the "slip" is put are to be made with sufficient bevil to enable the
dried cement to readily deliver itself. I prefer that this drying apparatus
should be put near to a burning furnace or kiln, so that the dried cement
may be placed at once on to the burning kiln before it has lost its heat.
I
When, however, from any cause it may be inconvenient to thus deal
with the dried cement I prefer to continue the chamber to the right
hand beyond the fire inlet b, and to allow the air which is to support
the combustion of gas, or an independent fire, to traverse over the out-
going trays and cement so as to take heat up from them, and this
heated air I then conduct by a suitable channel to the gas or to the
fire the combustion of which it is to support, the cement, under this
condition of things, being taken off not at g, but as much further to the
right hand as is equal to the length of the cooling chamber, and taken
off in a cold or cool condition.
For economy of space on the Drawing the chamber a is shewn much
shorter than it would be built in practice. It is also shewn with the
hcat operating on the upper sides of the trays only, it obviously can be
constructed so that the heat can operate on both sides. I prefer the
above arrangement of drying kiln, but it is obvious that one of a circular
form, like the burning kiln of Figures 1 and 2 of this Sheet, might be
used, and that the other forms and arrangements of continuous and
non-continuous kilns described in relation to that burning kiln might be
employed for the drying kiln.
I am aware that it has before been proposed to dry "slip" on a
travelling bed, but it has been after previous moulding into bricks or in
the mass.
I wish it to be understood, therefore, that I do not make any
claim to such a mode of drying “slip.”

page_text: Having thus particularly ascertained and described the nature of my
Invention I wish it to be understood that I do not claim as my Invention
any of the portions or details when considered by themselves, or when
considered apart from the combination herein described as embodying
my improvements; but what I claim is,-
-
First. The general arrangements of furnaces or kilns and mode of
burning herein described, by which the whole or the greater part of
the carbonic acid produced in the kiln shall pass off without acting
on the fuel.
Second. The construction and arrangement, as herein described, of
drying kilns for "slip," by which the "slip" is dried and moulded into
pieces of uniform size at one operation.
In witness whereof, I, the said Frederick Joseph Bramwell, have
hereunto set my hand and seal, this Thirteenth day of September,
in the year of our Lord One thousand eight hundred and seventy-
onc.