Improvements in and relating to Bolting or Sifting.
Year: 1890

page_text: Date of Application, 18th Mar., 1890
Complete Specification Left, 20th Dec., 1890-Accepted, 18th Apr., 1891
PROVISIONAL SPECIFICATION.
Improvements in and relating to Bolting or Sifting.
I, XAVIER GUSTAVE EDOUARD DE FAUCOMPRÉ, of 95, Boulevard
Beaumarchais, Paris, in the Republic of France, Engineer, do hereby declare the
nature of this invention to be as follows:—
The object of this invention is a new bolting or sifting process in which the
material under treatment is caused to pass through a sieve under the simultaneous
influence of air suction and the peripheral speed of the sieve or bolter.
The apparatus in one form mainly consists of a vertical cylinder of variable size,
closed at one end and open at the other. The casing of the cylinder is made of
lattice net or equivalent work with meshes of greater or less width, as required.
The cylinder is placed in a separation chamber which receives the previously
crushed material which it is desired to sieve or bolt, from one or more hoppers
arranged in different points of its cover this cylinder receives its rotary motion
through any suitable gear. A felt or equivalent band or washer compressed
between two rings jointed by means of suitable bolts, forms the joint or connection
between the movable cylinder and the upper part of the separating chamber.
When it is deemed desirable to impart a high speed of peripheral rotation to the
bolting cylinder, the diameter of the same must be increased accordingly. In that
case however the connection between the upper crown of the cylinder and the wall
of the separation chamber cannot be formed without difficulty, while on the other
hand, owing to the large size, considerable friction is produced. I therefore in such
cases employ an arrangement in which the cylinder is surmounted by a solid or
unperforated cone which terminates in a cylindrical portion with which the joint
can be made in the same way as in the first mentioned arrangement. The material
is supplied to the separating chamber by suitable hoppers placed at the top. A.
fan is provided to create a suction of air through the open end of the cylinder and
the bent pipe connected to it.
The particles of material that are in suspension within the separating chamber,
are attracted towards the cylinder owing to the sucking action of the fan taking
place in the direction of the interior of the said cylinder. But they can only pass
through the meshes of the network by which the same is surrounded, if the
resultant of their motion, combined with the peripheral motion of the cylinder, is
not too much inclined, whereas all the particles which, owing to their bulk, have
not acquired a sufficient degree of speed by the time they reach the net-work are
repelled as soon as they come in contact with the same, by centrifugal action, and
descend to the bottom of the separating chamber. This bottom is provided with
an opening through which all the materials that have not passed through the sieve
are allowed to return to the grinding stones or other similar apparatus; while the
material that has been bolted is conveyed to a suitable collecting chamber. By
means of the same net-work even should its meshes be rather large, all degrees of
fineness may be obtained, all that is necessary in order to produce either very fine,
or coarse grained flour, is correspondingly to increase or decrease the peripheral
speed of the cylinder, under an always uniform air blast. Thus by the combination
of a carefully controlled speed of cylinder, a predetermined size of meshes, and the
given power of air suction, flour of any desired degree of fineness may be produced.
To enable the control to be carried to a nicety and to afford a still wider range
of possible reduction, I propose to combine an apparatus of two bolting cylinders,
fitted into each other and revolved in opposite directions.
It will be readily understood that the action will be substantially the same as
above described if, instead of rotating the cylinder, the molecules of the material

page_text: under treatment are themselves caused to rotate about the cylinder. It is therefore
possible to employ a stationary cylinder, and to admit the external air sucked in by
the fan into the interior of the outer casing or chamber; this may be effected by
means of blades or wings so arranged as to cause the air to gyrate around the
cylinder and in so doing to carry with it the material it is desired to sieve.
It is in this case necessary constantly to keep the surface of the sieve clean to
avoid obstruction of the meshes.
I will here mention four arrangements which may be used for the latter purpose.
(1) A brush may be applied against the surface of the cylinder and the latter
may be caused to make one complete revolution at predetermined intervals or to
move continuously but very slowly.
(2) The cylinder may be left stationary and a vertical brush arranged to turn
against the surface either continuously or intermittently.
(3) A brush may be made to reciprocate along the generating line of the cylinder,
and only to touch the latter during its downward motion so as to cause the lighter
materials to fall in the bottom of the outer chamber where there are no currents
of air.
(4) The gyratory motion of the air itself about the cylinder may be utilized to
keep the cylinder clean and unobstructed by the more or less energetic action of
the air upon its surface.
It might be suggested that the sieving surface need not be movable. But if say
a plane surface be kept stationary this at once does away with one of the means
that enable the fineness of the flour or grist to be varied at will. However in
adopting such an arrangement the fineness of the ground material may still be
controlled to a certain extent by admitting the air currents at a greater or less
angle. The cleaning of such sieving surface is effected by means of suitable
beaters exerting their action at regular intervals in quick succession.
It will be understood that a sieving surface other than cylindrical may be used
without departing from the principle of my invention, it may for instance be
polyhedric or indeed perfectly plane. In the latter case an endless wire gauze band
should be provided for the conveyance of such sieve; the said band being wound
upon and kept tight between two rollers only one of which need be positively
driven.
It may so happen that a certain amount of material after entering within the
sieve is not swept away by the current of air and collects in the lower portion of
the sieve. This material must of course if possible be conveyed back to the
crushing cylinders &c. For this purpose when the sieving surface is cylindrical,
the sieving cylinder terminates in an unperforated portion and its bottom portion
is likewise unperforated and of conical shape, leaving a space between its edges
and the unperforated portion. The material falls through the annular passage or
conduit on to the inclined walls of the bottom of the chamber while a suitable pipe
carries it back to the crushing plant.
This annular passage may with advantage be reduced to four separate orifices
forming the respective apices of the same number of pyramids the bases of which
then form the bottom of the cylinder itself.
A similar arrangement may be adopted where instead of the cylindrical sieving
surface is substituted a polyhedric surface.
The main features of this sieving or bolting system may in fact be summarized
as follows;
(1) It cannot become obstructed or clogged owing to the comparatively large
size of the meshes;
(2) The particles of the material touching the net-work themselves effect the
constant cleaning of the same while those showing a tendency to stick in the meshes
are repelled by centrifugal action ;
(3) The apparatus is durable owing to the fact that the meshes being of
comparatively large size very strong wire may be used for forming the network.
In another type of apparatus the bolting cylinder is inclined and the separating

page_text: chamber consists of a cylindrical casing surrounding the bolting cylinder and
capable of such rotary motion as will repel the particles of the material tending to
adhere to the walls of the chamber. While at the same time it causes the lighter
particles fit for sieving (which otherwise would be kept down by the heavier ones)
to rise to the top again.
Dated this 18th day of March 1890.
W. P. THOMPSON & BOULT,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Bolting or Sifting.
I, XAVIER GUSTAVE EDOUARD DE FAUCOMPRE, of 95, Boulevard
Beaumarchais, Paris, in the Republic of France, 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 :-
The object of this invention is a new bolting or sifting process in which the
material under treatment is caused to pass through a sieve under the simultaneous
influence of air suction and the peripheral speed of the sieve or bolter.
The accompanying drawing exemplifies two arrangements whereby my process
may be carried out.
Fig. 1 is an apparatus in which the sieve is vertical.
Fig. 2 is a modification wherein the sieve is inclined.
Fig. 3 illustrates the means used for connecting the bolting cylinder, with the
outer casing or chamber.
Fig. is a vertical section illustrating the application of a brush to clean
the reel.
Fig. 5 is a section of the cylinder bottom showing the device employed for
causing such portions of the materials as have not been previously carried away to
move towards the crushing apparatus.
Fig. 6 is a modification of this arrangement.
Fig. 7 illustrates the application of a spiral vane with a fixed cylinder.
Fig. 8 illustrates the employment of the sieving surface in the form of an endless
band and
Fig. 9 illustrates a fixed sieve set at an angle in a tube.
The apparatus in one form as in Fig. 1, mainly consists of a vertical cylinder A
of any desired size closed at one end and open at the other. The wall of the
cylinder is made of lattice net or equivalent work with meshes of greater or less
width as required.
The cylinder is placed in a separation chamber B which receives the previously
crushed material, which it is desired to sieve or bolt from one or more hoppers
arranged in different points of its cover; the cylinder receives its rotary motion
through any suitable gear D E. A felt or equivalent band or washer F compressed
between two rings secured by means of suitable bolts forms the joint or connection
between the movable cylinder and the upper part of the separating chamber.
When it is deemed desirable to impart a high speed of peripheral rotation to the
bolting cylinder the diameter of the same must be increased accordingly. In that
case however the connection between the upper crown of the cylinder and the walls
of the separation chamber carnot be formed without difficulty while on the other
hand owing to the large size considerable friction is produced. I therefore in such
cases employ an arrangement shown in Fig. 4 in which the cylinder is surmounted
by a solid or unperforated cone c which terminates in a cylindrical portion d with
which the joint can be made in the same way as in the first mentioned arrangement
and which cone revolves with the cylinder. The material is supplied to the

page_text: separating chamber by suitable hoppers placed at the top. A fan is provided to
create a suction of air through the open end of the cylinder and the bent pipe C
connected to it.
The particles of material that are in suspension within the separating chamber
are attracted towards the cylinder owing to the partial vacuum produced in the
cylinder. But they can only pass through the meshes of the net-work by which
the same is surrounded if the resultant of their motion combined with the peripheral
motion of the cylinder is not too much inclined whereas all the particles which
owing to their bulk have not acquired a sufficient degree of speed by the time they
reach the net-work are repelled as soon as they come in contact with the same by
centrifugal action and descend to the bottom of the separating chamber. This
bottom is provided with an opening through which all the materials that have not
passed through the sieve are allowed to return to the grinding stones or other
similar apparatus while the material that has been bolted is conveyed to a suitable
collecting chamber.
By this arrangement of sieve and the same net-work-even should its meshes be
rather large all degrees of fineness may be obtained. All that is necessary in
order to produce either very fine, or coarse, grained flour, is correspondingly to
increase or decrease the peripheral speed of the cylinder under an always uniform
air blast. Thus by the combination of a carefully controlled speed of cylinder a
predetermined size of meshes and the given power of air suction, flour of any
desired degree of fineness may be produced.
To enable the control to be carried to a nicety and to afford a still wider range of
possible reduction I propose to combine an apparatus of two bolting cylinders fitted
into each other and revolved in opposite directions.
It will be readily understood that the action will be substantially the same as
above described, if instead of rotating the cylinder, the molecules of the material
under treatment are themselves caused to rotate about the cylinder. It is therefore
possible to employ a stationary cylinder and to admit the external air sucked in by
the fan into the interior of the outer casing or chamber; this may be effected by
means of blades vanes or wings so arranged as to cause the air to gyrate around the
cylinder and in so doing to carry with it the material it is desired to sieve; such an
arrangement being indicated in Fig. 7 where the spiral vane or blade E carried on
the revolving shaft F serves to accomplish this object.
It is in this case necessary constantly to keep the surface of the sieve clean to
avoid obstruction of the meshes.
I will here mention four arrangements which may be used for the latter
purpose.
(1). A brush may be applied against the surface of the cylinder and the former
may be caused to make one complete revolution at predetermined intervals or to
move continuously but very slowly, such a brush is shown in Fig. 4 secured to the
casing so that it would exert constant action upon the reel as the latter revolves.
Any suitable means may be adopted for revolving the brush where required.
(2). The cylinder may be left stationary and a vertical brush arranged to turn
against the surface either continuously or intermittently.
(3). A brush may be made to reciprocate in the direction of the axial line of the
cylinder and only to touch the cylinder during its downward motion so as to cause
the lighter materials to fall in the bottom of the outer chamber where there are no
currents of air.
(4). The gyratory motion of the air itself about the cylinder may be utilised to
keep the cylinder clean and unobstructed by the more or less energetic action of the
air upon its surface.
It might be suggested that the sieving surface need not be movable.
But if say
a plane surface be kept stationary this at once does away with one of the means
that enable the fineness of the flour or grist to be varied at will. However in
adopting such an arrangement the fineness of the ground material may still be

page_text: controlled to a certain extent by admitting the air currents at a greater or less
angle. In Fig. 9 a stationary bolting or sieving surface is represented. In this
case the component of speed obtained from the motion of the sieve not being
available is replaced by a proportionate inclination of the sieving surface Gin
relation to the direction of the air currents. This result is obtained by suitably
varying the angle of the sieve B to the line H representing the direction of the
sucking blast or current. The air and the material to be bolted enter at I.
The cleaning of the sieving surface G is effected by means of suitable tappers
exerting their action at regular intervals in quick succession.
It will be understood that a sieving surface other than cylindrical may be used
without departing from the principle of my invention; it may for instance be
polyhedric or indeed perfectly plane.
This
The apparatus illustrated in Fig. 8 consists of an endless band t t of wire gauze
stretched between two rollers a and b located within the recesses D D. One of
these rollers receives suitable rotary motion. One side of the endless band
forms one of the walls of the space C into which air is sucked through the
orifice C. The material to be bolted is introduced between the two parallel
parts of the endless band of wire-gauze. It may so happen that a certain
amount of material after entering within the sieve is not swept away by
the current of air and collects in the lower portion of the sieve.
material must of course if possible be conveyed back to the crushing cylinders &c.
For this purpose when the sieving surface is cylindrical I employ the arrangement
illustrated in Fig. 5. The sieving cylinder terminates in an unperforated portion f
and its bottom portion is likewise unperforated and of conical shape leaving a
space between its edges and the unperforated portion. The material falls through
the annular passage or conduit hon to the inclined wall i of the bottom of the
chamber while a suitable pipe carries it back to the crushing plant. This annular
passage h may with advantage be reduced to four separate orifices & forming the
respective apices of the same number of inverted pyramids the bases m of which
thus form the bottom of the cylinder itself as shown in Fig. 6.
A similar arrangement may be adopted where instead of the cylindrical sieving
surface is substituted a polyhedric surface.
The main features of this sieving or bolting system may in fact be summarized as
follows;
1. It cannot become obstructed or clogged owing to the comparatively large size
of the meshes;
2. The particles of the material touching the network themselves effect the
constant cleaning of the same while those showing a tendency to stick in the meshes
are repelled by centrifugal action.
3. The apparatus is durable owing to the fact that the meshes being of com-
paratively large size, very strong wire may be used for forming the network.
In Fig. 2 I have illustrated another type of apparatus only differing from the
preceding one in the angle of inclination of the bolting cylinder.
The separating chamber consists of a cylindrical casing surrounding the bolting
cylinder and capable of such rotary motion as will repel the particles of the
material tending to adhere to the walls of the chamber while at the same time it
causes the lighter particles fit for sieving (which otherwise would be kept down by
the heavier ones) to rise to the top again.
Having now particularly described and ascertained the nature of my sail inven-
tion, and in what manner the same is to be performed, I declare tha: what I
claim is :-
1. The sifting or bolting process enabling material of different degrees of fineness
to be graded by means of either a single sieve with wide meshes or two or more
concentric sieves moving in opposite directions through the combined action of the
peripheral speed thereof and the sucking power of a fan adapted to act within the
cylinders substantially as described.

page_text: 2. The employment in substitution for the cylindrical surface of a plane surface
either movable or stationary in which case the suction takes place at a certain
angle of incline in relation to the said surface substantially as described.
Dated this 20th day of December 1890.
W. P. THOMPSON & BOULT,
Agents for the Applicant.