Improvements in Apparatus for Use in the Preparation of Slurry for the Manufacture of Cement and in Mixing Slurry with Fuel.
Year: 1888

page_text: Date of Application, 18th Dec., 1888
Complete Specification Left. 18th Sept.. 1889-Accepted, 19th Oct., 1889
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Use in the Preparation of Slurry
for the Manufacture of Cement and in Mixing Slurry with Fuel.
I WILLIAM JOY of Northfleet in the County of Kent Cement Burner do hereby
declare the nature of this Invention to be as follows:-
In the preparation of slurry for the manufacture of cement it is important that the
chalk be finely crushed and the particles thereof thoroughly mixed with the clay as if
the chalk be imperfectly crushed and imperfectly mixed with the clay the cement
made by burning the slurry is liable to "blow." For the purpose of crushing the
chalk and mixing it with the clay the said matters are ordinarily passed through a
wash mill and the stream of matters passing therefrom is passed between millstones or
between rolls and in some cases the matters after passing between the millstones or the
rolls are passed through a sieve in order to separate the finer from the coarser portions
of the mixture.
My said invention consists in part of improvements in apparatus of the kind herein-
before referred to the object of this part of my said invention being to remedy certain
objections which attend the use of the ordinary apparatus and which are hereinafter
referred to. And my said invention consists further of the improvements hercinafter
described in apparatus for use in mixing slurry with fuel previously to charging it
into the kiln.
The outlet of the wash mill is ordinarily furnished with a grating consisting of bars
arranged in an upright position the object of which grating is to prevent the matters
in the mill from passing out until they have been sufficiently, acted on. I have found
that in consequence of the upright position of the bars of the said grating they offer
considerable resistance to the passage from the mill of the matters treated therein and
cause the said matters to accumulate near and obstruct the grating. In order to
remedy these objections I arrange the said bars lengthwise or in a horizontal or approxi-
mately horizontal position. I prefer to extend the grating further round the sides of
the mill than has heretofore been usual and to arrange the bars so near together as to
permit only the thoroughly ground matters to pass between them. Where the bars are
thus arranged the slurry may be passed direct from the wash mill to the drying floors
or to the kiln.
Where the mixture of matters or slurry passing from the wash mill is to be passed
between millstones the said slurry is ordinarily allowed to collect in a receptacle pro-
vided with an outlet orifice which is furnished with a valve or shutter by opening
which a stream of the slurry is allowed to pass to the millstones. This arrangement
acts imperfectly owing to the difficulty of adjusting the said shutter so as to cause the
slurry to pass to the stones at a rate proportional to their speed and owing to the
occasional obstruction or partial obstruction of the aforesaid outlet orifice by pieces of
uncrushed chalk. In order to remedy these objections I connect the aforesaid valve or
shutter with a governor actuated by connection with the millstones or the mechanism
or gearing by which they are driven so that the quantity of slurry passing to the mill-
stones is always proportional to their speed. Or I feed the slurry to the millstones or
control the flow of slurry thereto by means of a bucket wheel or a chain and buckets
or an archimedian screw or by means of any other suitable arrangement worked by
connection with the millstones or the aforesaid mechanism or gearing whereby the
flow of slurry to the stones is governed or controlled according to their speed.
Where the slurry is subjected to the action of rolls a pair of rolls is ordinarily used
both of which are caused to rotate. According to my said improvements I use one
roll only and I arrange the said roll in such a position relatively to the surface of a
plate or other surface (preferably curved) that the ingredients of the slurry are acted

page_text: on as required between the said roll and the said surface when the former is caused to
rotate.
Where the slurry is required to be passed through a sieve a cylindrical or conical
or approximately cylindrical or conical sieve rotating in a vertical plane is ordinarily
used the finer portions of the matters of which the slurry is composed passing through
the meshes of the sieve and the coarser portions passing over the upper edge thereof
by centrifugal action. Sieves thus constructed are liable to the objection that the
slurry collects on their inner surfaces and obstructs the meshes. In order to obviate
this objection I mount a cylindrical sieve within a suitable casing and on a stationary
shaft so as to be capable of rotation within the said casing and on the said shaft which
may be arranged either vertically or horizontally or at an angle. And I secure a drum
to the said shaft within the sieve on the outer side of which drum is an archimedian
screw which projects from the surface of the said drum and touches or nearly touches
the inner surface of the sieve. The method of using this arrangement and its action
are as follows:-The cylindrical sieve is caused to rotate and the slurry to be treated
therein is passed into it at one end. The finer portion of the said slurry passes
through the meshes of the sieve into the casing surrounding it and that portion which
does not pass through is by means of the said screw caused to travel along the
interior of the sieve and to pass therefrom at the end opposite to that at which the
slurry is fed in.
In constructing apparatus according to my invention for use in mixing slurry and
fuel I provide a receptacle for the fuel and a receptacle for the slurry and I arrange
archimedian screws in the said receptacles by which their contents are forced out into
a third receptacle containing stirrers or an archimedian screw in which latter receptacle
the slurry is mixed with the fuel by means of the stirrers or screw therein. By varying
the relative speeds of the screw in the slurry receptacle and the screw in the fuel
receptacle the proportion of slurry in the mixture relatively to the proportion of fuel
may be varied according to requirements.
Dated this 18th day of December 1888.
W. T. WHITEMAN,
Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Use in the Preparation of Slurry
for the Manufacture of Cement and in Mixing Slurry with Fuel.
I WILLIAM Joy of Northfleet in the County of Kent Cement Burner 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 :-
In the preparation of slurry for the manufacture of cement it is important that the
chalk be finely disintegrated and the particles thereof thoroughly mixed with the clay
as if the chalk be imperfectly disintegrated and imperfectly mixed with the clay the
cement made by burning the slurry is liable to "blow." For the purpose of
disintegrating the chalk and mixing it with the clay the said matters are ordinarily
passed through a wash mill and afterward between millstones or between rolls.
My said invention consists in part of improvements in wash mills the object of this
part of my said invention being to prevent the escape therefrom of the matters under
treatment until they have been sufficiently disintegrated and to facilitate the escape of
the said matters when sufficiently disintegrated.
Ordinarily in the outlet of the wash mill a grid or grating formed of bars arranged
in an upright position is set the object of which grating is to prevent the escape of the
chalk and clay from the mill before the lumps have been well broken up and the said
matters well mixed. I have observed that in consequence of the upright position of
the bars of the said grating considerable resistance is offered by theni to the motion of

page_text: the contents of the mill while passing them the consequence being that portions of the
matters under treatment in the mill accumulate near and obstruct the said gratings.
I have also ascertained that in consequence of the said resistance offered by the upright
bars it is impracticable to place them near enough together to prevent the escape from
the mill of insufficiently disintegrated chalk. According to my invention I provide
for reduction of the resistance offered by the gratings to the motion of the matters in
the mill by arranging the bars of which the said gratings are formed lengthwise or in
a horizontal or approximately horizontal position and I thus render practicable the
arrangement of the said bars at such distances apart as to insure the retention of the
chalk and clay in the mill until they are sufficiently disintegrated and intermixed to
admit of the slurry flowing from the wash mill being passed to the drying floors or to
the kiln without being subjected to the intermediate operation of grinding between
millstones or crushing between rolls. I however do not in all cases set the bars so
near together as is necessary to produce this result as where they are set at the
ordinary distance from each other and arranged lengthwise they do not resist the
motion of the matters in the mill and do not cause accumulations of the said matters
and consequent obstruction of the gratings as do the ordinary upright bars. In all
cases but especially where the bars are set very near together I prefer to extend the
grating farther round the mill than has heretofore been usual.
A convenient method of constructing the gratings according to my invention is
hereinafter described with reference to Figures 1 to 6 of the accompanying Drawings
Figure 1 being an elevation of one of the said gratings Figure 2 a plan of the same
Figure 3 an elevation and Figure 4 a plan of portions of the grating and Figures 5
and 6 sections of portions of the said grating taken respectively on the lines A B
Figure 4. The same letters and Figures of reference indicate the same parts in each
of the said Figures of the Drawings and in the other Figures of the accompanying
drawings hereinafter referred to.
The said grating is composed of a number of bars a a which are wider at one edge
than the other as shown in Figure 5 and are confined within a frame the top and
bottom of which consist of thicker bars bb rivetted to lengths of channel iron cc which
constitute the sides of the frame. The bars a a are kept at the required distances
apart by means of wedge shaped pieces of metal d d placed between them and retained
in position by means of rods e e passed through holes in the said bars a a and pieces d d
and secured by means of nuts et e¹ screwed onto their ends. In arranging the gratings
in the mill they are placed so that the wider edges of the bars are inwards or toward
the inner part of the mill. The bars a a are shown in Figures 3, 5 and 6 as set at a
distance of one thirty-second part of an inch apart which is sufficiently near to prevent
the passage between them of insufficiently disintegrated chalk.
A convenient method of arranging the gratings in a wash mill is hereinafter
described with reference to Figures 7 and 8 of the accompanying Drawings. Figure 7
being a plan of a wash mill having a number of the said gratings applied thereto and
Figure 8 a vertical section taken on the line c Figure 7.
fis the outer wall of the wash mill g is a framework of timber secured to the said
wall in rebates in which framework a number of the gratings hereinbefore described
are secured by means of buttons h has shown in Figure 8.
Outside that portion of
the wall of the wash mill in which the said gratings are secured walls ii are built
enclosing spaces jj into which the slurry issuing from the mill between the bars a a
of the grating passes into a channel k by which the said slurry is conducted from the
mill. The chalk is tipped into the wash mill at the part and the clay at the part m.
The harrows and the mechanism by which they are actuated are not shown in the
Drawings. The direction in which the harrows work is indicated by the arrow in
Figure 7.
In cases where the slurry passing from the wash mill is required to be ground the
said slurry is ordinarily passed into or allowed to collect in a receptacle provided with
an outlet furnished with a valve or shutter by opening which a stream of the slurry is
allowed to pass to the millstones. This arrangement acts imperfectly owing to the
difficulty of adjusting or varying the position of the said shutter so as to cause the

page_text: slurry to pass to the millstones at a rate proportional to their speed and owing
to the occasional obstruction or partial obstruction of the aforesaid outlet by pieces
of chalk.
According to my Invention I obviate the former of the said objections by connecting
the aforesaid valve or shutter with a governor actuated by connection with the mill-
stones or the mechanism or gearing by which they are driven so that the said valve or
shutter is closed when the millstones are at rest and is opened when they are in motion
the extent to which the said valve or shutter is opened being dependent on the speed
at which the millstones are driven. Where this arrangement is used it is only
necessary to remove the obstructions herein before referred to as they accumulate in
order to ensure the automatic supply of slurry to the stones at a rate proportional to
their speed. Where it is desired to avoid the said accumulation of chalk and the
consequent necessity for removal of the same while the mill is in action I provide for
the feeding of the slurry to the millstones or for the control of the flow of slurry
thereto by means of a bucket wheel or a chain and buckets or an Archimedian serow
or by means of any other suitable arrangement worked by connection with the mill or
the mechanism or gearing by which it is driven whereby the millstones are fed or the
feeding of slurry thereto is governed or controlled according to their speed.
An arrangement in which a sliding valve or shutter controlling the flow of slurry to
the millstones is actuated by a governor to which motion is communicated from the
mechanism of the mill is illustrated in Figure 9 of the accompanying Drawings.
Referring to the said Figure m is the casing of the millstones m' is the hopper into
which the matter to be ground is fed. nnn is the gearing by which the mill is
driven o is a tank for containing the slurry to be ground o¹ is a shoot for directing a
stream of slurry from the tank o to the hopper m' and o' is the valve or shutter by
raising which the slurry is allowed to escape from the tank o which shutter is mounted
in slides oo in the shoot o' so as to be capable of being raised or lowered in the said
slides. p is the governor which rotates with the mill spindle and p¹ is a lever jointed
to a bracket p² secured to the tank o and connected to the governor p so as to bo raised
when the mill is in action and also connected to the shutter o by passing through a
hole of therein. By means of the said apparatus the supply of slurry to the millstones
is automatically governed proportionally to their speed.
An arrangement in which the slurry is fed to the mill by means of a bucket wheel
worked by connection with the gearing of the mill is illustrated in Figure 10 of the
accompanying drawings which is an elevation of portions of a mill and the gearing
thereof corresponding to that shown in Figure 9 hereinbefore described. Referring to
the said Figure 10 g is the bucket wheel which works in a tank containing the slurry
to be ground and is driven from the shaft n of the mill gearing by a band q¹ passing
over pulleys q n³. 93 are the buckets on the wheel g. s is a trough which receives
the slurry from the said buckets and s¹ is a shoot by which the slurry passes from the
said shoot to the hopper m¹. The arrangement of the trough s relatively to the bucket
wheel g
is shown in Figure 11 which is an elevation of the said parts taken at right
angles to the elevation Figure 10 the shoot s¹ being in section taken on the line D
Figure 10.
An arrangement in which the slurry is fed to the mill by means of a chain and buckets
is illustrated in Figure 12 of the accompanying Drawings in which Figure the said chain
and buckets are marked t t. The other parts of the said Figure are essentially similar
to the arrangement illustrated in Figure 10 herein before described and are marked
with corresponding letters and figures of reference.
An arrangement in which the slurry is fed to the mill by means of an archimedian
screw is illustrated in Figure 13 of the accompanying Drawings. Referring to the
said Figure is the archimedian screw which works in a casing u¹ connected to a
tank to which slurry is supplied by any suitable means. The arrangement for
actuating the screw u by connection with the gearing of the mill is clearly shown in
the Drawing and is essentially similar to that described with reference to Figures 10
and 12. On the screw u being caused to rotate the slurry is raised from the tank u
up through the casing u' and falls into the hopper m³ of the mill.

page_text: Other arrangements for feeding or controlling the flow of slurry to the millstones by
means of apparatus worked by connection with the mill gearing are illustrated in
Figures 14 and 15 of the accompanying Drawings. In the arrangement Figure 14
the slurry is fed to the stones or its flow from the tank containing it is controlled by
means of vanes vv carried by a boss v¹ secured to a spindle mounted in a trunk.
communicating with the slurry tank and terminating in a shoot which delivers the
slurry to the hopper m². In the arrangement Figure 15 the slurry is fed to the mill-
stones or its flow thereto 'is controlled by a sliding valve w working in a trunk x com-
municating with the slurry tank which valve is connected by a rod w¹ to a pin on a
crank plate w carried by a shaft driven by connection with the mill gearing recipro-
catory motion being thus communicated to the valve wo when the mill is working.
The slurry passes from the trunk at each outward motion of the valve w through an
outlet. The position of the valve w when at the extremity of its inward traverse is
indicated in dotted lines.
In constructing apparatus according to my invention for use in mixing slurry and
fuel I provide a receptacle for the fuel and a receptacle for the slurry and I arrange
archimedian screws in the said receptacles by which their contents are forced out
into a third or mixing receptacle containing stirrers or an archimedian screw in which
latter receptacle the slurry is mixed with the fuel by means of the stirrers or
screw therein. By varying the relative speeds of the screw in the slurry receptacle
and the screw in the fuel receptacle the proportion of slurry in the mixture relatively
to the proportion of fuel may be varied according to requirements.
An apparatus thus constructed is illustrated in central vertical section in Figure 16
of the accompanying Drawings in which Figure y is the slurry receptacle y¹ is the
screw therein which is connected to a rotatory shaft y carrying a band pulley y'. z is
the fuel receptacle z¹ is the screw therein is the shaft of the screw and z³ is a band
pulley secured to the said shaft. 1 is the mixing receptacle 2 is the shaft therein
33 are the stirrers carried by the said shaft and 4 is a band pulley secured thereto.
By means of bands passed over the pulleys y³ ³ and 4 the apparatus is connected to
and actuated by any suitable motor or motors. The mixed slurry and fuel passes from
the receptacle 1 at the exit 5.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
:-
First The improvements herein before described in wash mills that is to say the
arrangement of the bars of the grids or gratings of the exits of wash mills lengthwise
or in a horizontal or approximately horizontal position.
Secondly The improvements hereinbefore described in arrangements for feeding or "
controlling the flow of slurry to millstones that is to say arrangements by which the
slurry is fed to the millstones or the flow of slurry to the millstones is automatically
controlled according to the speed of the mill by means of apparatus connected to or
actuated by the mechanism by which the mill is driven.
Thirdly The improvements in apparatus for mixing slurry with fuel illustrated in
Figure 16 of the accompanying Drawings.
Dated the 18th day of September 1889.
W. T. WHITEMAN,
Agent for the Applicant.