Improvements in Kilns for Burning Portland Cement, Roman Cement, or other Hydraulic Cements or Lime.
Year: 1895

page_text: Date of Application, 15th June, 1895
Complete Specification Left, 2nd Mar., 1896-Accepted, 4th Apr., 1896
PROVISIONAL SPECIFICATION.
Improvements in Kilns for Burning Portland Cement, Roman
Cement, or other Hydraulic Cements or Lime.
We, AUGUST Waldemar Lundberg, of Lomma Manager of Cement Works,
and JOHAN OLOF HALLGREN of Limhamn, Manager of Cement Works, both
places in the Kingdom of Sweden, and VERNER FREDERIK LŒESSÓE SMIDTH of
3 Amalievej Copenhagen V, in the Kingdom of Denmark, Civil Engineer, do
hereby declare the nature of this invention to be as follows :--
. Our present invention relates to improvements in kilns for burning Portland
cement, Roman cement and other hydraulic cements, or line.
In the manufacture of such cements the raw materials are ground together,
either with water, or dry. In both cases the raw material, of which the cement is
produced by burning, takes the shape of dried blocks either of an irregular shape,
or moulded in the shape of bricks. It is through the burning that the chemical
combination takes place, which gives to the cement the property of setting..
For this burning have mostly been used vertical or bottle-kilns, which are
working periodically, i.e. being charged with fuel and materials in alternate
layers, and, after burning, being left to cool until the burnt charge can be taken
out and another put in. These kilns are often used in combination with drying
chambers for the slurry, but also in many cases without such drying chambers.
Though many later constructions of kilns have been introduced, which are
working on the continuous system, that is by uninterrupted burning, the charge.
being continuously fed in at one end and the burnt clinker continuously drawn at
the other end-by which systems great saving in fuel has been experienced, still
these old fashioned periodical kilns are commonly used, the only objection against
them being that they require much fuel to do their work.
We
Now, our present invention has for its object an arrangement by which a great
saving in fuel can be attained, and it consists in a better mode of working these
periodical kilns. In order to do this we close the kiln at the bottom and introduce
compressed air from a blower by means of a suitable conduit, which can be in the
shape of a wide tube of plate iron, or built in bricks, concrete or the like.
find by experience that a very considerable saving is obtained by burning the
charge of the kiln by means of this blast instead of by natural draught. The
manner of closing the kiln at the bottom depends of course on local circumstances,
but we generally prefer to use sliding doors of plate iron which are closed and
tightened by means of cement slurry or some suitable mortar.
The advantage of our system consists in considerable saving in fuel and an
increase of the output. The smaller bulk of fuel in the layers will allow an
increased bulk of the raw bricks or dried slurry in the charge and, besides, we
find that the time occupied by the burning process is considerably shortened, so
that, taking these two circumstances together, the output of the kiln is nearly
loubled.
In the accompanying drawing, Figures 1 and 2 show the arrangement of an
ordinary chamber-kilu with our improvements added: a is the inlet of compressed
air from the blower, b is the opening at the bottom of the kiln through which the
cement clinker are drawn, and c are the sliding doors by which this opening can be
closed..
In cases where no drying of slurry or cement bricks is wanted, by the waste
heat from the kilns WA combine the severel kilns with one another
Thia

page_text: arrangement is shown in Figures 3, 4 and 5 of which Fig. 3 is a front elevation,
Fig. 4 an end view with section through a vertical flue and Fig. 5 a ground plan.
In these figures only two kilns are shown, but the system is applicable to any
number of kilns. Between each two kilns we erect a vertical flue or chimney F.
The kilns are provided with dampers at the top, and a flue of plate iron, lined
with fireclay connects the inside of the kiln, near the top, with the vertical flue F,
while another plate iron flue lined with fireclay connects the bottom of this
chimney with the bottom of the next kiln. Both of these flues are provided
with valves so that they can be opened or closed at will. Besides this con-
nection, each of the kilns is separately provided with conduits for compressed air
from the blower, at the bottom." The mode of working the kiln consists in letting
one kiln burn with the top-damper open and with blast from under, until all
moisture is evaporated, which can easily be seen by the sudden raising of the
temperature of the smoke from the kiln. As soon as the burning of this kiln
has proceeded thus far, the top damper is closed and the connection with the
vertical flue F, and through this with the bottom of the next kiln, is opened.
The blast under the first kiln will then force the dry hot smoke from the first
kiln through the second and all the heat contained therein, which would other-
wise be wasted, is now used in heating and drying the charge of the second
kiln. When the burning of the first kiln is completed, and it is so far cooled
that very little heat remains, the blast is shut off from this, the top damper
opened and the kilns left for further cooling while blast is introduced under the
second kiln which in the meantime has taken fire, and the same mode of
working is continued from kiln to kiln. In this way, all the kilns being.
connected, a very considerable saving in fuel and a great increase of the
output may be attained by the relatively small cost required for this
arrangement.
The kilus in Figs. 3, 4 & 5 are provided with sliding doors c and the openings be
must further be closed by means of a wall d which also serves to protect the
doors c against the heat.
In connection with this improved system of burning we have found that, during
the burning, a great deal of inflammable gases leave the kiln which is under fire;
in order to utilize these gases we add a supply of air into the flue connecting the
vertical chimney with the bottom of the kiln which is drying. This gas will then
burn and the heat developed will further assist the drying and heating of the
charge in the second kiln.
Dated the Thirteenth day of June 1895
AUGUST WALDEMAR LUNDBERG.
JOHAN OLOF HALLGREN.
VERNER FREDERIK LŒESSOE SMIDTH.
Improvements in Kilns for Burning Portland Cement, Roman
Cement, or other Hydraulic Cements or Lime.
We, AUGUST WALDEMAR LUNDBERG, of Lomma, Manager of Cement Works,
and JOHAN OLOF HALLGREN of Limhamn, Manager of Cement Works, both
places in the Kingdom of Sweden, and VERNER FREDERIK LŒESSÓE SMIDTH of
3 Amalievej, Copenhagen V, in the Kingdom of Denmark, Civil Engineer, do
hereby declare the nature of this invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement :-
Our present invention relates to improvements in kilns for burning Portland.
cement, Roman cement or other hydraulic cements or lime.

page_text: In the manufacture of such cements, the raw materials are ground together,.
either with water, or dry. In both cases the raw material, of which the cement
is produced by burning, takes the shape of dried blocks either of an irregular
shape, or moulded in the shape of bricks. It is through the burning that the
chemical combination takes place, which gives to the cement the property of
setting.
For this burning have mostly been used vertical or bottle-kilns, which are
working periodically, i.e. being charged with fuel and materials in alternate
layers, and, after burning, being left to cool until the burnt charge can be
taken out and another put in. These kilns are often used in combination with
drying chambers for the slurry, but also in many cases without such drying.
chambers.
Though many later combinations of kilns have been introduced, which are
working on the continuous system, that is by uninterrupted burning, the charge
being continuously fed in at one end and the burnt clinker continuously drawn at
the other end-by which systems great saving in fuel has been experienced-still
these old fashioned periodical kilns are commonly used, the only objection against
them being that they require much fuel to do their work.
Now our present invention has for its object an arrangement by which a great
saving in fuel can be attained, and it consists in a better mode of working these
periodical kilns. In order to do this we close the kiln at bottom and introduce com-
pressed air from a blower by means of a suitable conduit, which can be in the shape
of a wide tube of plate iron, or built in bricks, concrete or the like. We find by
experience that a very considerable saving is obtained by burning the charge of
the kiln by means of this blast instead of by natural draught. The manner of
closing the kiln at the bottom depends of course on local circumstances, but we
generally prefer to use sliding doors of plate iron which are closed and tightened.
by means of cement slurry or some suitable mortar.
The advantage of our system consists in considerable saving in fuel and an.
increase of the output. The smaller bulk of fuel in the layers will allow an
increased bulk of the raw bricks or dried slurry in the charge and, besides, we
find that the time occupied by the burning process is considerably shortened so-
that, taking these two circumstances together, the output of the kiln is nearly
doubled.
In the drawing left with the Provisional Specification, Figures 1 and 2 show.
the arrangement of an ordinary chamber kiln with our improvements added ; is
the inlet of compressed air from the blower, b is the opening at the bottom of the
kiln through which the cement clinker are drawn, and c are the sliding doors by
which this opening can be closed.
In cases where no drying of slurry or cement bricks is wanted, by the waste.
heat from the kilns, we combine the several kilns with one another. This
arrangement is shown in Figures 3, 4 and 5 of which Fig. 3 is a front elevation,.
Fig. 4 an end-view with section through a vertical flue and Fig. 5 a ground plan..
In these figures only two kilns are shown, but the system is applicable to any
number of kilns. Between each two kilns we erect a vertical flue or chimney F..
The kilns are provided with dampers at the top and a flue of plate iron, lined with.
fireclay connects the inside of the kiln near the top with the vertical flue F, while
another plate iron flue lined with fireclay connects the bottom of the chimney with.
the bottom of the next kiln. Both of these flues are provided with valves so that
they can be opened or closed at will. Besides this connection, each of the kilns is
separately provided with conduits for compressed air from the blower at the
bottom. The mode of working the kilns consists in letting one kiln burn with the
top damper open and with blast from under, until all moisture is evaporated,.
which can easily be seen by the sudden raising of the temperature of the smoke
from the kiln. As soon as the burning of this kiln has proceeded thus far, the
top damper is closed and the connection with the vertical flue F and through this.
with the bottom of the next kiln is opened. The blast under the first kiln will.

page_text: then force the dry hot smoke from the first kiln through the second and all the
heat contained herein, which would otherwise be wasted, is now used in heating
and drying the charge of the second kiln. When the burning of the first kiln is
completed, and it is so far cooled that very little heat remains, the blast is shut
off from this, the top damper opened and the kilns left for further cooling, while
blast is introduced under the second kiln which in the meantime has taken fire
and the same mode of working is continued from kiln to kilu. In this way all
the kilns being connected, a very considerable saving in fuel and a great
increase of the output may be attained by the relatively small cost required for
this arrangement.
The kiln in Fig. 3, 4 and 5 are provided with sliding doors c and the openings b
must further be closed by means of a wall d which also serves to protect the
doors c against the heat.
In connection with this improved system of burning we have found that during
the burning, a great deal of inflammable gases leave the kiln which is under fire.;
in order to utilize these gases we add a supply of air into the flue connecting the
vertical chimney with the bottom of the kiln which is drying. This gas will
then burn and the heat developed will further assist the drying and heating of the
charge in the second kiln.
•
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare, that what we
claim is:
1. In ordinary vertical kilns for burning cement the improvements of closing the
bottom of the kiln and introducing blast of compressed air from a blower,
particularly as described.
2. In ordinary vertical kilns the combination of the said arrangement of closing
the bottom of the kiln and introducing blast of compressed air with an arrangement
by which the kilns are put into communication with one another, the top of each
kiln, being connected with the bottom of the next through vertical flues or chimneys
and connecting flues, particularly as described.
3. In vertical kilns as under 2, the arrangement of special supplies of air to the
connecting flues between the vertical chimneys and the bottoms of the kilns in
order to light the inflammable gases, contained in the fumes and thus utilize the
heat contained therein, particularly as described.
Dated this 22nd day of February 1896.
I. O. HALLGREN.
A. W. LUNDBERG.
VERNER FREDERIK LOSSÒE SMIDTH.