Improvements in the Processes and Manufacture of Cement in a Powdered State and the Apparatus relating thereto.
Year: 1886

page_text: Date of Application, 12th June, 1886.
Complete Left, 12th Apr., 1887.
Complete Accepted, 10th May, 1887.
Improvements in the Processes and Manufacture of Cement in a
Powdered State and the Apparatus relating thereto.
I FREDERICK WILFRID SCOTT STOKES of 13 Holland Street Kensington London, W.,
Civil Engineer, do hereby declare the nature of this invention to be as follows:-
My Invention consists in the improved methods of Producing Cement, for building
or other purposes, so as to render unnecessary the present system of grinding the cement
"clinker" after burning as well as other improvements.
The process may consist of the following operations viz :-Thoroughly mixing and
grinding chalk, clay or mud, or other ingredients in the required proportions (with as
little water as practicable), in a plastic state between suitable stones or rolls, the product
being forced through small holes or other contrivance into a chamber or chambers,
through which pass currents of heated air, or products of combustion.
The dried "Slurry" thus formed is then passed through heated rolls or stones and
ground, or otherwise pulverized to a fine powder, which is then heated and afterwards,
blown with, or otherwise mixed with heated air so as to be held in suspension, when it,
and the accompanying, air may be further heated and drawn or blown, together with
gas, coal dust or other inflammable matter or combustible, or through incandescent
fuel, into a combustion chamber or chambers, properly shaped and contrived, if
preferred with additional, coal dust, gas, air, or other jets so as to attain the high
temperature necessary for converting the aforesaid powder into cement, which is next
led into other chambers to settle, or to be otherwise mechanically separated from the
products of combustion such flues, passages or chambers being arranged, so as to as
far as possible heat the air and cement powder passing on its way to the combustion
places.

page_text: The highly heated cement being also as far as practicable utilized for heating
purposes; the air, gas coal dust or other combustibles.
The waste products of combustion, having been separated from the cement, are then
led away by flues or passages and brought into contact with the previously mentioned
plastic "slurry" in a divided state, so as readily to drive off all or part of the contained
moisture, or to be otherwise utilized for heating or drying floors or chambers.
"
The slurry when dry to be pulverized as previously described, and passed
through the various stages mentioned for the conversion into cement.
Finally, the cement having cooled, and remained the required time in heaps is ready
for use or may be passed through suitable screens if desired.
All the apparatus being contrived, so as to minimize the manual labour necessary
for performing the various processes.
Dated this the 10th day of June 1886
FREDERICK WILFRID SCOTT STOKES.

page_text: Powdered State and the Apparatus relating thereto.
I, FREDERICK WILFRID SCOTT STOKES, of 13 Holland Street, Kensington, in the
County of Middlesex, 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:—
My invention relates to the manufacture of cement for building and other purposes,
and to apparatus for use in such manufacture.
Various attempts have been made to provide for burning "slurry" or other cement
material after the reduction of the same to powder; but the methods hitherto adopted
have proved more or less unsatisfactory.
My invention comprises an improved method or process and apparatus whereby this
operation may be successfully and advantageously accomplished. In burning the
powdered slurry or other cement material, according to my said invention, I introduce
the same by means of one or more jets of air or gas, in which the particles of the said
material are held in suspension, into a closed chamber, in which the said material,
while still held in suspension, is subjected to the action of a flame of the required
temperature and for a sufficient length of time to convert it into cement. The particles
of cement are then separated from the gases or products of combustion by gravity or
by centrifugal force or in any other convenient manner. I prefer to utilize these gases
or products of combustion in the other processes hereinafter described.
My said invention also comprises an improved method or process of drying the
slurry or other cement material before its reduction to powder. For this purpose I
divide the said material into thin strips or sheets and pass it through a suitable drying
chamber.
My said invention, moreover, comprises various improvements hereinafter set
forth.
In the accompanying drawings, I have illustrated improved apparatus whereby the
manufacture of cement according to my invention may be continuously carried on.
Figure 1 is a vertical longitudinal central section of apparatus for drying and
pulverizing the slurry or other cement material.
Figure 2 is a transverse section on the line x, x, Figure 1.
Figures 3 and 4 show, in horizontal section, apparatus for burning the powdered
material and separating the particles of cement from the gases or products of combustion.
Figure 5 is a vertical longitudinal central section of part of the apparatus shown
in Figure 3.
Figure 6 shows a part of Figure 5 drawn to an enlarged scale.

page_text: is a ver men central section, also drawn to an enlarged scale, showing a
slight modification of the apparatus illustrated in Figure 6.
Figure 8 is a vertical longitudinal section on the line x¹, x¹, Figure 4.
Figure 9 is a transverse section on the line, ³, Figures 4 and 8.
Figure 10 is a vertical longitudinal central section showing a modification of the
apparatus illustrated in Figure 3.
of
Figure 11 is a vertical longitudinal central section illustrating another modification
my said invention.
Figure 12 is a vertical longitudinal central section, and,
Figure 13 a transverse section on the line, ., Figure 12, illustrating a further
modification of my said invention.
Like letters indicate corresponding parts throughout the drawings.
In manufacturing cement according to my said invention, I first blend chalk and
clay or mud in the usual proportions for the formation of slurry, or I mix other
suitable ingredients according to any of the methods heretofore practised to produce
a cement material. In preparing the slurry, I prefer to mix the clay and chalk in,
or about in, the proportions of one part of clay to five parts of chalk.
The "slurry" or other cement material is passed, together with water, between
edge-rollers so as to intimately mix or thoroughly unite the chalk and clay or the
like, the quantity of water added being only such as to render the mixture plastic and
easily workable, without rendering it too fluid. The quantity required will vary
according to the condition of the materials, but it may be roughly taken as from
30 to 40 per cent. of water to the perfectly dry "slurry." It is important that there
should be a perfect union between the chalk and the other materials, therefore the
mechanical mixing must be conducted with great care, and sufficient time be allowed
for effecting this operation, which, in some cases, may take as much as 24 hours,
according to the precise nature of the materials used.
The slurry, after it has been passed between rollers as above described, is
introduced into a pug-mill, such as that shown at a in Figure 1, provided with
revolving helical blades or knives a¹, whereby the slurry is still further mixed so as
to increase its homogeneity, and is brought to about the consistency of dough. The
pug-mill is preferably provided with a steam-jacket for the supply of heat to further
assist in the mixing. The slurry, as it issues from the lower end of the pug-mill,
passes between two rollers 6, 6' arranged to rotate in a frame or casing 62 provided
with scrapers c for removing the slurry from the said rollers; the slurry is fed by
these rollers into a lower chamber d with considerable pressure. This chamber,
which is preferably formed of cast iron, is long and narrow; it extends downward
and terminates in a rounded end or bottom d, in which are formed holes of say
from one-half of an inch to one inch in diameter. Through these holes the plastic
slurry, now perfectly mixed, is forced in the form of thin strips. The said holes may
be of any convenient shape so as to produce strips of slurry of the form best
adapted for facilitating the drying of the same.
The said holes are so arranged
that the strips of slurry will be delivered side by side upon an endless chain or band e
formed of iron bars coupled by means of links. This endless chain or band is
supported upon chain-wheels e and rollers e³, and is provided with means whereby
it may be caused to slowly travel through a drying chainber f traversed by heated air
or by the gases or products of combustion from the burning chamber hereinafter
described.
The chamber is provided with dwarf walls f¹, f' so arranged as to cause the
heated air and gases or products of combustion to alternately ascend and descend
through the endless chain or band and thus effectually and economically heat the
slurry and drive off the moisture therefrom.
The hot air or gases enter the drying chamber at f³ and pass through the same in
the opposite direction to the endless chain or band, as indicated by the arrows in
Figure 1, therefore the dry slurry will issue at as high a temperature as practicable.
The said hot air or gases leave the drying chamber at f.

page_text: The endless chain or band e passes through an aperture in each end of the drying
chamber and returns in a cavity f beneath the floor of the said chamber; or it may
return along the floor of the chamber itself, if desired.
The length of the chamber and the speed at which the endless chain or carrier e
travels will depend in some measure upon the amount of waste heat available from the
burning apparatus hereinafter described, or upon the temperature of the heated air
used for drying the slurry, and also upon the thickness of the ropes, bands or strips of
slurry. The speed of the endless chain or carrier should, moreover, be suitably pro-
portionate to the speed at which the strips of slurry are forced out of the
chamber d. It is, however, essential that the slurry should be delivered perfectly
dry and well heated, which will generally be the case after from ten to fifteen
minutes exposure of the same in the drying chamber f.
On issuing from the drying chamber f, the dry slurry falls into the pan g' of a
mortar-mill or grinding-mill g of any suitable and well-known construction. A
circular scraper or brush is provided, which is driven in the opposite direction to the
endless chain or carrier e, to assist in detaching the slurry from the said chain or
carrier.
On falling into the grinding-mill, the slurry is readily pulverized by the revolving
stones or iron rollers, which are provided with suitable scrapers for causing the
material to pass frequently under the rollers in a well-known manner, so as to
ensure the requisite fineness of the powdered material. The said powdered material
is continuously removed from the pan by other scrapers and is delivered into a
revolving screen k. This revolving screen should be set on an inclination of about 1
in 15 to 25, and should be formed of wire netting, preferably of steel, having say from
2,500 to 4,000 meshes to the square inch. Beneath the said screen is arranged a
trough k¹ set at the same inclination as the screen and curved in transverse section to
the same radius as the exterior of the screen. The said screen is completely covered
in or enclosed by a casing k³. An archimedian screw k³ is fixed upon the screen k and
serves to feed the screened material along the trough into a hopper, trough or
chamber 1, whence it is conveyed by means of elevators or screw-conveyors to a bin or
the like, from which it may be fed as required into the burning apparatus hereinafter
described. It is advantageous to store up a quantity of the dry powdered slurry at
this stage of the process so as to be independent of any temporary stoppage of the
grinding or other machinery, which would otherwise delay the burning process;
moreover, the latter process may be better regulated when carried on independently of
the preceding processes.
The pieces of material which cannot pass through the fine meshes of the screen fall
from the open end of the said screen, and are returned to the crushing or grinding
mill g.
From the said bin or the like, powdered material is next conveyed in any convenient
manner into a hopper m (Figure 5) forming part of the apparatus for burning the said
material and converting the same into cement.
The material falls from the hopper m into a chamber n, in which a preliminary
heating of the powered cement material takes place. The material should be caused,
as far as practicable, to retain the heat imparted to it in the drying process. The
temperature to which it is raised by the said preliminary heating will depend upon
circumstances. As a rule from 450 to 800 degrees Centigrade will suffice, but the
higher the temperature the more economical will be the subsequent burning.
In the apparatus shown in Figures 3 and 5 for effecting the preliminary heating of
the powder, there is a trough n' in which is arranged a horizontal or slightly inclined
screw-conveyor n². The heat is obtained from a small furnace o in which gas or other
fuel is consumed, and from which the products of combustion pass through the lower
part of the chamber n beneath the trough n' and return through the said trough,
following the convolutions of the screw-conveyor. When starting the apparatus, care
should be taken that the temperature of the parts exceeds 150 degrees Centigrade so as
to drive off the condensed vapour of combustion.

page_text: Although it is not absolutely necessary to heat the slurry powder before burning,
yet I prefer to do so on account of the economy thus effected.
The powdered material falling from the hopper m is conveyed along the trough n¹
by the screw n² and is thus regularly fed into a hopper p at the upper end of a feed
pipe p', which hopper is provided with cross bars or pieces designed to break up any
fumps that may be formed by the adherence of particles of the material to each other,
and thus render the feed as uniform as practicable. A pipe q is provided which
extends down centrally into the hopper pand is connected with a reservoir or other
apparatus for the supply of air under a pressure of say from 8 to 12 inches of water.
This pipe terminates, near the lower end of the hopper p, in a small nozzle q' as shown
more clearly in Figure 6, so as to form, with the contracted part of the said hopper, a
kind of injector whereby the slurry powder is introduced into the feed pipe p² in a
state of suspension in air; some of this air being supplied through the pipe 7 and the
remainder entering through the hopper p.
The mixture of air and powder enters the feed pipe p¹ with considerable force. It is
very important that the material should at this time be in a finely divided state and
not in lumps, as these would not burn to good cement. To ensure this result, the jet
of air and powder is preferably made to impinge upon a disc p² secured in an
enlarged portion p³ of the feed pipe p', so that the particles of the material will be
effectually separated from each other. The said disc is subject to considerable wear,
and is, therefore, so arranged as to be readily renewable. The separation of the
particles may, if desired, be effected by dividing the stream of air and powder into
two equal parts and causing them to impinge against each other in the form of jets,
with sufficient force to thoroughly break up any lumps that may exist, before the
material passes along the feed pipe; for this purpose the part pa is divided into two
branches p, p, which terminate opposite each other in the pipe pas shown in
Figure 7.
Both the compressed air and that entering through the hopper p should be heated
as far as practicable by the heat from the waste products of combustion from the
burning chamber. The compressed air jet should be under perfect control and only so
much air used as is absolutely necessary to convey the powder into the burning
chamber, so as to avoid choking the feed pipe.
The feed. pipe p₁ terminates at the entrance to a larger pipe or nozzler communi-
cating with the combustion chamber A in which the powdered slurry is to be burnt and
converted into cement. This combustion chamber is connected with a regenerator or
regenerating furnace B. This regenerator is provided with valves or doors C, C¹ which
may be adjusted so as to permit the products of combustion from the chamber A to
pass through either side of the said regenerator. Air is admitted to the other side of
the regenerator through the opening D and, after being heated, passes through an
opening D¹ into a flue E whereby it is conducted to the pipe or nozzle r. The flue E
is formed with an aperture E¹ for the supply of heated air to the feed pipe p' through
the hopper p.
Around the end of the feed-pipe p¹ and at the entrance of the larger pipe or
nozzle r, a ring jet or blast s is arranged, which is to be supplied, through a pipe s',
with heated air under a pressure of say from 8 to 12 inches of water. The hot air
from the regenerators is thus drawn to this point through the flue E and forced into
the combustion chamber A under a pressure of say from three-eighths of an inch to
one inch of water. This pressure is preferable to that which is obtained by the use of
a chimney, as it tends to produce a higher temperature of combustion and also
facilitates the operations in the drying chambers, where the low temperature and excess
of carbonic acid gas renders a sufficient chimney-draught very difficult to obtain.
Around the nozzle is an annular space or chamber F which is to be supplied with
gas through a pipe F¹. Air is also forced by means of a ring jet from the flue E
into an annular space or chamber G around the neck of the combustion chamber,
which is perforated to permit the entrance of this air so that it will mix with
the gas.

page_text: The powdered slurry is further mixed with heated air in the nozzler and is injected
through the said nozzle into the combustion chamber A. On entering the said
chamber, the air containing the slurry powder is met and surrounded by the
inflammable gas admitted through the pipe F and chamber F. The gas, on entering
the combustion chamber, is ignited. The temperature in the said chamber should be
raised to from 3000 to 4000 degrees Fahrenheit, after the requisite manipulation of
the regenerators, before any slurry powder is introduced. This temperature is
necessary to effect the conversion of the slurry powder into cement, that is to
drive off the carbonic acid and form soluble silicates. For this purpose, it is
preferable to use a flame of say from 8 to 14 feet in length, the length of flame
required varying with the other conditions of the case. The temperature of the flame
can readily be judged from its colour, which should be one of intense whiteness.
The temperature is controlled by regulating the supply of gas and of air and slurry
powder, and also the relative proportions of these substances.
The burning process requires great care to ensure uniform results.
say,
to
The gas used may be produced from coal, petroleum or other hydro-carbon. Any
of the gas-producers now well known may be employed. I prefer to use coal-gas and
to obtain it from a producer having a closed hearth and an outlet at the back for the
gas, and fed with air under pressure in the front, the coals being introduced from the
top by a feed hopper. The gas thus produced should be conducted under a pressure
of from three-quarters of an inch to one-inch-and-a-half of water, along pipes or flues
into the combustion chamber; the supply should be under perfect control by means
of valves.
The producer or producers should be as near the combustion chamber as practicable,
in order to avoid loss of heat on the passage of the gas thereto. If preferred, the gas
on its way from the producer to the combustion chamber may be further heated by
passing it through regenerators, such, for instance, as are used in the manufacture of
steel. I do not, however, consider such heating necessary when the producers can be
placed near to the combustion chamber.
The combustion chamber should be lined with fire-brick. It is important that the
proportions of this chamber should be such as not to cramp in any way the natural
proportions of the flame, that is to say, roughly taking the diameter of the gas-inlet
as I, the greatest diameter of the combustion chamber should be say 3 and its length
from 9 to 14.
The combustion chamber may be either vertical or horizontal, the latter position is
preferable as the said chamber can be more readily connected with the regenerators
without bends in the flues, which are objectionable by reason of the liability of the hot
cement to cling to the sides or walls.
At the end of the combustion chamber opposite the nozzle r, the products of
combustion and the cement dust in suspension therein pass into one or other of the
regenerating and settling chambers B1, B2, where a portion of the heat of the cement
and products of combustion is stored up to be imparted to the air or gas which is
afterwards allowed to pass through the said chamber into the flue E. The gas or air
is thus heated before its combustion, and the temperature of the flame at the point of
ignition thereby correspondingly raised. The air or gas traverses the chambers B1, B2
in the opposite direction to the products of combustion, so that it attains the maximum
temperature at the outlet D¹.
The end of the combustion chamber is preferably provided with cold air inlets A¹ so
arranged as to keep the valve C cool.
The chambers B1, B2 are lined with fire-brick and are provided with rows of fire-
clay tiles t arranged longitudinally in the said chambers and supported upon bearers t¹.
These tiles facilitate the settling of the cement-dust and also increase the area of
surfaces for storing up heat.
The products of combustion should be made to pass as slowly as practicable through
these chambers and the said tiles should be so arranged as to encourage the deposit of
the cement-dust on the floor of the said chambers.. For this reason, the regenerator
must be much larger than would otherwise be necessary.

page_text: The products of combustion, after the cement has been separated therefrom, pass
through the outlet H. They are preferably conducted through a suitable flue to the
inlet of the drying chamber f, as they still retain sufficient heat to enable them to
be utilized in the drying process.
As soon as the cement has collected on the floor of the regenerator in sufficient
quantities, it should be removed by hoes through openings in the side walls. This
should be done towards the end of the period when the chamber is being used for
heating the air, to enable the cement to give up as much of its heat as practicable.
The cement raked out of the regenerator falls upon a sunk floor, where it is allowed
to cool for a time; it is then removed by a screw-conveyor or otherwise to floors to be
spread out to "weather," after which it is ready for use. If the above described
operations have not been successfully carried out, it may sometimes be necessary to
pass the cement-dust through sieves and the residue through edge-rollers or burr-
stones to produce the required amount of pulverization.
In Figure 10, I have illustrated a modification of my burning apparatus, in which
the feed pipe p is extended to near the entrance or neck of the combustion chamber A.
In this modification, the chamber F, through which the gas is passed, is arranged
between the said feed-pipe and the passager for the heated air from the flue E. If
desired, gas may be supplied through the passage r¹ and air through the chamber F.
Figure 11 shows a modification of my apparatus wherein I provide for obtaining
the heat for burning the slurry, directly from incandescent fuel. K is a blast-furnace,
which is connected by a short flue or passage K¹ with the combustion chamber A.
The feed pipe pl is inserted in the upper part of the flue K and is curved at its lower
end so that the air and slurry powder will be directed into the said combustion
chamber. The furnace K is charged with coke and is worked with either hot or cold
blast directed into it through tuyeres K2. Carbonic oxide and hydrocarbon gases are
formed in the furnace, and unite with the air introduced together with the slurry..
In some instances, I pass the feed pipe p' through the furnace, as indicated by the
dotted lines, so that the air and slurry powder will be heated to some extent by the
incandescent fuel before they enter the combustion chamber. It is sometimes
advantageous to provide for the separation of the particles of cement from the gases
or products of combustion after they have passed through the regenerating furnace or
apparatus. For this purpose, 1 prefer to employ apparatus such as that shown in
Figures 12 and 13, wherein L is a spiral or helical flue or chamber, into which the
cement and the said gases or products of combustion are conducted through a flue L',
and from which the said gases or products of combustion are conducted through a
flue L², to the drying chamber f. M is a flue which extends through the centre of
the said helical chamber, and through which the air or gas to be used in burning the
slurry or other cement material are to he passed. The chamber L communicates, by
means of apertures or passages L³, with a pipe or passage N in which is arranged
a screw-conveyor N¹. As the powdered cement is carried at a considerable velocity
through the helical chamber L by the gases or products of combustion, the particles
of cement are thrown by centrifugal force into the pipe or passage N through the
passages L³, which are tangential to the chamber L. The cement, as it collects in the
pipe or passage N, is removed therefrom by the screw-conveyor N¹.
When the regenerating furnace or apparatus is arranged vertically, I prefer to
provide it with inclined slabs extending from the centre and side walls alternately,
and to form apertures or passages in the side walls above the slabs which are connected
thereto. These passages communicate with pipes or passages in which are arranged
screw-conveyors. The cement and products of combustion will pass between the said
slabs, which will deflect the particles of cement so that the latter will fall into the
aforesaid pipes or passages, whence they will be removed by the screw-conveyors.
I sometimes provide for heating the slurry powder to some extent before introducing
it into the burning apparatus, in the following manner, that is to say I place the
slurry powder in a chamber of fine clay or other refractory substance, heated on all 5
sides as far as practicable by means of a gas or other furnace and provided with
cross-tubes or narrow chambers through which the heated products of combustion

page_text: slowly pass, and, by reason of the conductivity of the walls, impart heat to the slurry
powder contained in the said chamber. The said powder is continuously but slowly
removed at the bottom of the chamber by a revolving wheel. This wheel has formed
in its periphery a series of cavities, so that it will, in each revolution, remove a definite
or regular quantity of the powder.
Although I prefer the above described method of mixing and drying the slurry or
other cement material, yet I wish it understood that any existing method, when
preferred, may be used for producing the dry powdered slurry or other cement
material, so long as perfect mixing and dryness of the materials are obtained together
with the proper degree of fineness. I also wish it understood that my improved
drying process may be used independently of the other processes hereinbefore
described. Moreover any other suitable apparatus may be employed for effecting
the preliminary heating of the dry cement material.
It is obvious that my improved apparatus may be further_modified, in some
measure, without departing from the nature of my invention. For instance, I may
substitute for the revolving screen shown in Figure 1, a shaking or vibrating screen
or other suitable device for sifting the powdered material. Moreover instead of
employing the regenerating furnace or apparatus above described, I can use a series
of flues arranged parallel to each other, and cause the cement and the gases or
products of combustion to pass through alternate flues while the air or gas to be
heated passes through the remaining flues.
In some instances, instead of dividing the plastic slurry or other cement material
into thin strips, as above described, I form it into a thin sheet which is conveyed
through the drying chamber by means of the endless chain or carrier.
The powdered slurry or other cement material may be held in suspension in gas,
instead of in air, and introduced therewith into the combustion chamber, sufficient
air being introduced into the said chamber to adequately support the combustion
therein.
Although I prefer to use compressed for forcing the air or gas through the various
chambers or flues yet in some instances, chimney-draught can be employed for this
purpose.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed I wish it understood that I do not
claim generally or irrespectively of my improvements as herein set forth the manu-
facture of cement by first drying the slurry or other cement material and reducing it
to powder and then burning the powdered material; but I claim ;-
First. The improved process consisting in introducing the powdered slurry or
other cement material, while held in suspension in air or gas, into a chamber,
subjecting it in the said chamber, while still held in suspension, to the action of heat
to convert it into cement, and then separating the particles of cement from the gases
or products of combustion, substantially as above set forth.
Second. The improved process consisting in forming or dividing the plastic slurry
or other cement material into thin strips or sheets and passing it in this form through
a drying chamber, substantially as, and for the purpose, above set forth.
Third. The improved process consisting in first dividing the plastic slurry or other
cement material into thin strips or sheets and passing it in this form through a drying
chamber, and then pulverizing the dried material and subjecting it, while held in
suspension in air or gas, to the action of heat to convert it into cement and separating
the particles of cement from the gases or products of combustion, substantially as
above set forth.
Fourth. The combination of a pug-mill or equivalent mixing apparatus, a drying
chamber provided with means for conveying the plastic cement material through the
same in thin strips or sheets, a grinding-mill and a screen, substantially us, and for the
purposes, above set forth.

page_text: Fifth. The improved means, substantially as described with reference to either of
the forms or modifications shown in the accompanying drawings, whereby I provide
for introducing the powdered material into the burning chamber while held in
suspension in air or gas, as above specified.
Sixth. The improved regenerating furnace or apparatus, substantially as described
with reference to Figures 4, 8 and 9 of the drawings, whereby I provide for separating
the cement from the gases or products of combustion and for heating the air or gas to
be used in the burning process, as above specified.
Seventh. The improved apparatus consisting of the parts constructed and combined
substantially as described with reference to Figures 1 to 9 of the accompanying
drawings and operating as, and for the purposes, above specified.
Eighth. The modification of my invention, substantially as described with reference
to Figure 11 of the drawings, wherein I utilize the heated gases from a blast-furnace
for burning the slurry or other cement material, as above specified.
Ninth. The improved apparatus, substantially as described with reference to
Figures 12 and 13 of the drawings, for separating the cement from the gases or
products of combustion as above specified.
Dated this 12th day of April 1887.
FREDERICK WILFRID SCOTT STOKES.
Haseltine, Lake & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.