IMPROVEMENTS IN THE MANU-. FACTURE OF CEMENT, AND IN THE TREATMENT OF CEMENT PRODUCING OR ANALOGOUS MATERIALS
Year: 1877

page_text: LETTERS PATENT to Thomas Russell Crampton, of 13, Victoria Street, in the
City of Westminster, for the Invention of "IMPROVEMENTS IN THE MANU-.
FACTURE OF CEMENT, AND IN THE TREATMENT OF CEMENT PRODUCING OR
ANALOGOUS MATERIALS."
Sealed the 7th December 1877, and dated the 22nd June 1877.
PROVISIONAL SPECIFICATION left by the said Thomas Russell Crampton
at the Office of the Commissioners of Patents on the 22nd June 1877.
THOMAS RUSSELL CRAMPTON, of 13, Victoria Street, in the City of Westminster.
"IMPROVEMENTS IN THE MANUFACTURE OF CEMENT, AND IN THE TREATMENT OF>
CEMENT PRODUCING OR ANALOGOUS MATERIALS."
Heretofore in the manufacture of Portland and other cement the material from
which the cement is to be made after being prepared has been usually formed into
blocks or broken into lumps of various sizes, and such blocks or lumps have been
stacked or piled (usually with alternate layers of fuel) in kilns and burnt, the
products of combustion passing through interstices formed between the lumps
arranged for this object.
According to my Invention I effect the burning of cement material when in a
powdered or comparatively finely divided state in a furnace or kiln, in which the
particles or pieces of cement material are by agitation or otherwise kept in motion,
and so are continuously exposed to the action of the heat; this may be effected in
various ways.
The powdered or finely divided cement material may be injected into or caused
to drop down a chamber heated by any ordinary means, or by the combustion of a
mixture of gas, oil, or powdered fuel, and atmospheric air, the powdered cement
material being either injected with the air and fuel, or separately.
By preference I employ a slowly revolving heated chamber. The finely divided
cement material if supplied to the chamber at one end will be continuously turned
over and over, and will travel slowly to the opposite end from which it may be
allowed to fall into a suitable receptacle, the heat traversing in the contrary
direction to the cement, by which means the cement is gradually heated and the
waste heat efficiently utilized.

page_text: Any dust particles carried by the current of gases through the apparatus may be
collected or stopped and caused to mix with the mass, returning with it through the
chamber.
The cement as it falls may pass through a stream of air entering the furnace to
support the combustion of fuel therein, or in contact with pipes through which such
air passes, so as to heat the air before it comes into contact with the fuel com-
bustible gases, or fuel in small particles may also be supplied to the furnace or
chamber and caused to mix with the cement material, or the fuel may be mixed
with the cement material previously to its entering the furnace.
The heated products of combustion passing from the furnace may also be utilized
for drying the cement material previous to its being burnt.
In some cases steam boilers may be heated by a part of the heat generated in
burning the cement.
By burning cement in the manner above described I am also enabled to manu-
facture cement direct from the raw materials by a continuous operation. For this
purpose in the case of Portland cement I effect the mixing together of the chalk and
clay from which such cement is formed in a pug mill, by preference a horizontal pug
mill, consisting of a long trough having two shafts revolving therein, and each
carrying a number of knife blades. The raw or prepared clay is supplied at one
end of the trough, together with previously ground or reduced chalk; the materials
are by the revolving knives caused to travel slowly forwards along the trough and
are at the same time intimately mixed together.
The trough may be covered over, and the waste heat from the furnace passed
through it. By this means, the mixed material in a comparatively dry and partially
pulverized state is passed' into the furnace to be burnt, and when burnt is discharged
from the furnace.
Other arrangements of apparatus capable of intimately mixing chalk and clay,
with or without the addition of water, as for example, successive pairs of revolving
rollers may be used, and the mixed material passed.in like manner direct from the
mixing machinery to a drying chamber and furnace; or the cement material may
be prepared by the ordinary wet method and dried, then reduced to small pieces
and burned in the furnace. After burning the cement it is ground to powder by the-
ordinary well-known manner
:
A similar method of manufacture may be employed in burning lime and other
cement producing materials or analogous substances.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Thomas Russell Crampton in the Great Seal Patent Office on the 21st
December 1877.
THOMAS RUSSELL CRAMPTON, of 13, Victoria Street, in the City of Westminster.
"IMPROVEMENTS IN THE MANUFACTURE OF CEMENT, AND IN THE TREATMENT OF
CEMENT PRODUCING OR ANALOGOUS MATERIALS."
Heretofore in the manufacture of Portland and other cement the material from
which the cement is to be made after being prepared has been usually formed into
blocks or broken into lumps of various sizes, and such blocks or lumps have been-
stacked or piled (usually with alternate layers of fuel) in kilns and burnt, the
products of combustion passing through interstices formed between the lumps
arranged for this object.
According to my Invention I effect the burning of cement material in a furnace
chamber or kiln, in which the particles or pieces of cement material are by
mechanical agitation, kept in motion intermittently or continuously, and so are con-
tinuously exposed to the action of heated gases, resulting from the combustion of
coal or carbonaceous material passing through the chamber; this may be effected in
various ways.
By preference I employ a slowly revolving circular or polygonal shaped chamber
made of iron or other suitable material, lined with fire-bricks for the whole or part
of length as may be deemed necessary, and heated by the gases resulting from
the combustion of coal or carbonaceous material.
The revolving chamber I mount either at a slight angle from the horizontal or in
a horizontal position. In this latter case I provide it with internal angular projec-
tions or agitators, in order that the cement material if supplied to the chamber at
one end where the waste heat escapes shall as the chamber revolves be continuously
turned over and over, and at the same time caused to travel slowly to the opposite
end where the heat is generated, and from which it is allowed when sufficiently
burned to fall into or through a suitable passage or receptacle; the heated gases are
therefore caused to traverse the chamber or apparatus in the contrary direction to
the cement. By this arrangement the cement material is gradually heated and
burnt, and the heat from the furnace efficiently utilised.
I prefer to heat the chamber by injecting into it a mixture of air and finely
powdered carbonaceous material, in the manner described in the Specifications of
previous Patents granted to me, and now well known and employed for heating
revolving puddling furnaces.
The cement material may be introduced into the chamber in a moist state, so that
any dust particles carried by the current of gases through the apparatus may be
collected or stopped and caused to mix with the moist material, returning with it
through the chainber.
The burned cement as it falls away from the chamber may pass through a stream
of air entering the furnace to support the combustion of fuel therein, or it may be
brought into contact with pipes on one side of them whilst air passes on the other
side, thereby heating the air before it comes into contact with the fuel; the air
travels in a contrary direction to the cement, entering the furnace nearly at the same
temperature as the cement leaves it; or the heated air may be forced from these
pipes and caused as it enters the furnace to take with it the powdered or gaseous
fuel in any ordinary and well-known manner. The hot cement may also if required
be cooled by passing it into the end of a long trough, and screwing it along the
trough a sufficient distance to cool it, the trough and screw being cooled by water or air
passing through them; or the cement material may be partially cooled direct by water
being conducted to it, only so much water should be used as the heat in the cement
can evaporate, leaving the cement quite dry, or by any other convenient means.
Fuel in small particles may also be supplied to the furnace or chamber and caused
to mix with the cement material to assist in burning it; this fuel when the furnace

page_text: rect by pow red mer may be inserted by so arranging the quantity injected
that a portion only is consumed at end of the furnace whilst the remainder falling
in its passage into the cement mixes with, and on arriving at a proper temperature
is consumed in direct contact with it, sufficient air being allowed to enter the
furnace for this purpose; or the fuel may be mixed with the cement material
previously to its entering the furnace.
The heated products of combustion passing from the furnace may if desired
be utilized for drying the cement material in a separate apparatus previous to its
being burnt.
In some cases steam boilers may also be heated by a part of the heat generated
in burning the cement.
In place of burning the cement material by a continuous operation in a revolving
chamber heated by gases passing through it, in the manner above described, the
burning may be effected by intermittent operations, a charge of cement material
being introduced into a revolving furnace and heated up and burnt, the furnace
being turned slowly during the process, then taken out and another charge inserted;
or a charge of cement material might similarly be placed into a fixed furnace and
be continuously or from time to time turned over and over by mechanical agitators,
or by tools worked by hand until it has been heated up and burnt.
In this system
the waste heats may be employed for preparing the material, as in the case of the
continuous process previously described.
By burning cement in the manner above described I am enabled to manufacture
cement direct from the raw materials by a continuous operation, since if the
revolving chamber be sufficiently long and sufficient time be given the operation,
the ordinary slip or wet ground material may be introduced into it at one end, and
delivered as burnt cement at the other end, suitable agitators for given distances along
the chamber being arranged to stir or break up the material in its transit; or if a
shorter revolving chamber is employed I may effect (say, in the case of Portland
cement) the mixing together of the chalk and clay from which such cement is
formed in a pug mill, by preference a horizontal. pug mill, consisting of a long
trough having two shafts revolving therein, and each carrying a number of knife
blades. The raw or prepared clay is supplied at one end of the trough, together
with previously sufficiently ground or reduced chalk or other analogous material;
the materials are by the revolving knives caused to travel slowly forwards along the
trough, and are at the same time intimately mixed together.
The pugging trough may be covered over, and the waste heat from the furnace
passed through it to the chimney. By this means the mixed material in a com-
paratively dry and partially pulverized state is passed into the furnace to be further
dried and burnt, and when burnt is discharged from the furnace, and any dust
produced during the burning is taken up or deposited in the wet material in its
passage through the pug mill.
Other arrangements of apparatus capable of intimately mixing chalk and clay,
with or without the addition of water, as, for example, successive pairs of revolving
rollers, may be used, and the mixed material passed in like manuer direct from the
mixing machinery to a drying chamber and furnace; the drying may also be
effected by passing the material on a series of moveable webs placed in a closed
chamber, or by screwing it through a succession of chambers in a zig-zag direction,
the heat passing in the opposite direction, or by any other well-known means.
In some cases the drying chamber may be a continuation of the revolving furnace;
the material may enter wet into the drying chamber and be carried forward by it
into the furnace, thereby being gradually dried and finally burned, making its exit
at the hottest end of the furnace, any dust evolved in the process being caused to
come in contact with the wet material where it is deposited before arriving at the
chimney; or the cement material may be prepared by the ordinary wet method and
dried, then reduced to small pieces and burned in the furnace. A chamber or
chambers may also be constructed for the purpose of depositing and collecting any
dust suspended in the current of the heated gases before making its exit at the

page_text: chimney. After burning the cement it is ground to powder by the ordinary well-
known manner.
The foregoing description will give sufficient information for the construction of
the apparatus to anyone skilled in such matters, but there are appended Drawings,
numbered 1, 2, 3, 4, of a general nature to further illustrate the continuous system.
In Figure 1, A, is a hopper into which are fed the prepared or required wet
materials, which are mixed in the apparatus B, B, consisting of two or more chambers
placed in a zig-zag form containing pug shafts, and being at the same time partially
dried by the hot gases from the furnace passing through them up the chimney.
The gases pass from the furnace through a flue O, and enter the chambers B at 0¹.
The cement materials fall gradually from here upon two rollers C, which further
crush and deliver them to the coolest part E of the revolving chamber which runs
on rollers, they becoming gradually hotter as they are conveyed to the other end F
of the revolving chamber, from which they make their exit sufficiently burnt,
dropping through the cooling apparatus G, cooled by air, they make their final exit
at H ready for being ground. The cold air passes thraugh the pipes L, then up the
passage M, entering heated the combustion chamber N, where it meets the fuel to be
consumed.
Figure 2 is a section through the revolving chamber, shewing projections.
Figure 4 shows an arrangement without special drying apparatus. The mixed
cement materials fall into the hopper A¹, and are fed by the rollers C¹ into the
furnace D. Here the drying apparatus is a continuation of the furnace and in a
line with it. The cement materials are agitated by means of a stirrer Q' or other-
wise, gradually dried, heated, and burnt at the same time, advancing towards the
end F where they lead and fall through a zig-zag cooling chainber G¹ into a hori-
zontal chamber R¹, through which they are screwed, dropping out at H¹ ready for
being ground. The cold air entering the chamber R₁ by the pipe R², passing along
it up the zig-zag chamber in contact with the hot cement materials, and then into
the furnace in a heated condition, meeting the combustible gases that may be
produced from a furnace such as shewn, or any other form of furnace.
Figure 3 is a section through the part of furnace in which the drying operation
takes place, shewing the stirrers.
Having thus described the nature of my Invention and the manner of performing
the same, I would have it understood that I do not confine myself to the exact
modes herein described of carrying out my Invention, as other modes may be used,
so long as the main features of the Invention are maintained, but I claim,―
First. The burning of Portland and other such like cement in chambers or
furnaces in which the cement material is kept in motion either continuously or
intermittently by mechanical agitation during the burning operation, substantially as
herein described.
Second. The burning of Portland and other such like cement in revolving
furnaces heated by the gases resulting from the combustion of coal or carbonaceous
material passing through them, substantially as described.
Third. The burning of Portland and other such like cement in revolving furnaces
heated by the combustion of air and powdered carbonaceous material, substantially
as described.
Fourth. The manufacture of Portland and other such like cement direct from the
raw materials, substantially as described, the inixing, drying, and burning and
cooling of the materials being effected in a continuous operation.
In witness whereof, I, the said Thomas Russell Crampton, have hereunto set
my hand and seal, this Twentieth day of December, in the year of our
Lord One thousand eight hundred and seventy-seven.
T. R. CRAMPTON. (LS.)