Manufacturing Portland Cement.
Year: 1886

page_text: Manufacturing Portland Cement.
I WILHELM SONNET, Manager of the Portland Cement Manufactory, Beckum, in
the Empire of Germany, 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 :-
to
In the manufacture of Portland Cement according to the present invention, the raw
materials, properly mixed and finely ground, are sifted upon a sieve of 900 meshes to
the square centimetre, and carried at once, by means of a conveying worm, into a
channel-shaped furnace of peculiar construction, and there burnt. During the trans-
port of the raw material through the conveying worm, the mass will be heated
up
from 100 to 150° C., and on being delivered into the "burning" furnace (which is
heated up to from 2500 to 3000°), will be there burnt, whilst in the state of powder.
The apparatus employed for carrying out this manufacture is represented in the
accompanying Drawings in vertical longitudinal section at Fig. 1, in plan at Fig. 2,
and in cross section at Fig. 3.-Fig. 4 represents a section through the fire places.
The apparatus consists of a channel furnace A and the generators B situated outside
the furnace, which latter serve for the production of the hydrogen or mixed gases for
heating the furnace.-The bends of the channel furnace A, as seen at Fig. 1, are, at
the front portion a, inclined, but at its rear portion, become a series of vertical
shafts b, situated close together, and connected one with another.
The lowermost portions d d of the channel a bare provided with lateral openings
capable of being closed, and designed for the withdrawal of the burnt cement which
becomes collected at these parts. The channel abis provided throughout its whole
length with "service"
openings e e, for the purpose of allowing of the removal of any
cement which may have remained upon the floor of the furnace, and also to enable the
entire burning process to be watched.
The gas necessary for the heating of the furnace is produced in two double
generators B B, Figs. 3 and 4.-These are set in operation alternately, in such a way;
that whilst one generator is in action, the other is being supplied with fresh fuel

page_text: through the supply hoppers -The hoppers fare of such a capacity that their
contents suffice for one supply of fuel for the fire place.
Immediately under the grids of the fire places, are arranged tubes g, which are
provided with a number of small holes, and are fed from a common tube g¹ with
superheated steam. The admission of the steam can be stopped by means of cocks g³.
The superheated steam issuing from the tubes g passes through the layer of fuel on
the grids, and the hydrogen or mixed gas thereby produced passes through the
channels (which are capable of being closed by valves ) into the gas holder or
collector, from whence it passes to the furnace channel a through a number of
small channels m set at an inclination thereto.
The distribution of the channels m will be seen from Fig. 1; by means of their
inclined arrangement, the tar which forms at their exit point, through the burning
operation, will be caused to flow back into the gas holder or collector k, in which also
a separation of tar takes place, which, however, flows back into the furnace through
the channels 4, and will be again used for the production of gas.
The flame issuing from the first (i.c., the lowermost) channel m serves for the
preliminary heating of the air entering the furnace channel ab through the opening n,
which air is necessary for the complete burning of the gas.-Heated air will also be
admitted from the space underneath the first bend of the furnace channel a b, for
each further flame, so that a temperature of 3000° can easily be attained in a furnace
channel of suitable length.
The furnace channel a can be made of any desired or suitable length, according
as the raw material for the Portland Cement is easier or more difficult to burn.
The supply of the material to be burnt is effected by means of a conveying worm p
situated over the entire length of the channel furnace A, and in which the mass to be
burnt receives, during its transport, a preliminary heating up to from 100 to 150
degrees, by means of the heat radiating from the furnace. The mass falls finally
through the admission shaft into the furnace channel, where the same is evenly
distributed by means of the hot air and gases of combustion rushing upwards with
great force, so that the burning process will be completed evenly. The finer portions
of the cement mass falling in through q will be drawn by the draught in the furnace
channel over the bend a', and into the furnace channel itself; the single particles of
the mass to be burnt encounter one another again in the channel, join soon together
in consequence of the high temperature, and fall, so soon as they are heavy enough,
onto the floor of the furnace channel, where they then become completely incrusted
together. The completely burnt Portland Cement collects in the deepest parts d d
of the channel a b, and will be drawn out thence from time to time. The heavy
portions of the cement falling in through q fall down into the first incline of the
furnace channel as unburnt material, and collect together at n. These also will be
from time to time removed, again ground, sifted, and again placed in the conveying
worm p, in order to be again conducted to the furnace channel.
For the purpose of creating the necessary draught, the end of the furnace
channel a is connected with a large exhauster through a serpentine or zig-zag
shaped tube (Fig. 5).-The length of this tuber must be considerable, in order to
give the issuing gases opportunity to become thoroughly cooled before they reach the
exhauster, so that the latter, during a long continued working, shall not become too
hot. In the exit of the issuing gases, there will also be about 40 to 50 per cent of the
burnt cement-material drawn with them through this tube. This cement-material
collects, in part, in the lower bends of the tube, and will be drawn out thence through
the opening of valves t; another portion, however, passes through the exhauster, and
is thrown by the same into a "dust chamber," in which it settles down, and will be
gathered, after cooling, as completely-formed cement.
As will be seen, the burning of the cement in this apparatus proceeds continuously.
By the use of my invention, also, the moistening, the forming into blocks or slabs,
the drying of the slabs, the setting in of the same, as also the difficult burning and
drawing-out of the cement-mass from the still hot furnace, of the old process, are all
dispensed with, whilst, in my invention, the entire mass to be burnt is conveyed

page_text: automatically to the furnace, and 75 per cent of the burnt mass is carried out
automatically, so that only 25 per cent has to be removed from the furnace, and that.
easily by hand labour, from outside. My invention has also the peculiarity of
considerably improving the Portland Cement, as the cement will be free from
remaining portions of fuel, and free also from raw cement material. In addition, the
cost of manufacture is considerably diminished by the use of my invention, which
also, from a sanitary point of view, is an important improvement in the manufacture
of Portland Cement, as the workmen are much less exposed to dust and heat than in
the processes heretofore employed.
Of equal importance, finally, is the circumstance, that with this improvement, it is
possible to stop the working on Sundays; for this purpose, it is only necessary to put
the generators B out of action, and to close the valves h. The cooling of the apparatus
during 24 hours is scarcely perceptible.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed, I declare that what I claim is :-
1. The mode of manufacturing Portland cement herein before described, by
conveying the well-mixed and finely ground raw-mass, in the form of powder, directly
into a serpentine "channel furnace," and there burning the same.
2. In the manufacture of Portland cement, the use of an apparatus consisting of a
serpentine furnace channel ab provided with admission shaft g, and being at its rear
end in connection with an exhauster through a serpentine or zigzag tube T₁ such
apparatus being also provided with a gas holder karranged in close proximity to the
furnace channel, which gas holder is fed by means of generators B with mixed gases
or hydrogen, and gives off its gas, through a continuous series of small channels m,
into the furnace channel a b, for the purpose set forth.
of
3. In combination with the "burning" apparatus herein shown and described, the
adaptation of a conveying worm p situated directly above the apparatus, which leads
the mixed and ground cement raw-material continuously to the admission shaft
the furnace channel a b, for the purpose of effecting the preliminary heating of the
raw material of the cement during its passage to the apparatus.
NEWTON & SON,
Agents for the Applicant.