IMPROVEMENTS IN BOLTING OR SIFTING MACHINES
Year: 1885

page_text: I, HERBERT JOHN HADDAN, of 67, Strand, in the City of Westminster, Civil
Engineer, do hereby declare the nature of said invention for IMPROVEMENTS IN
BOLTING OR SIFTING MACHINES, a communication to me from abroad by the firm
of Escher Wyss and Company, Engineers, of Ravensburg, in the German Empire,
to be as follows:-
The bolting machine hereafter described, and represented in the accompanying
drawing is superior to others hitherto in use, as it can be driven with little power
and has a rational method of action.
The beaters, hitherto used in centrifugal bolting-machines, generally consist of
strips of sheet iron, which are either quite flat or slightly curved lengthwise, and
mostly inclined somewhat backwards.
A great disadvantage is attached to such an arrangement, namely the beaters
produce a strong current of air, and, consequently, great pressure against the
sifters of the cylinder (just as with blast fans). Such bolting machines, therefore,
consume a great deal of power and, owing to the pressure of the air, the sieves
become clogged with particles of flour larger than the meshes of the sieve, which,
therefore, cannot allow the fine particles of flour to pass through, while the coarser
and heavier particles are driven round the sifter by the air current circulating
with the beaters, and soon destroy the silk gauze.
Another kind of beaters, provided with holes or slits, works more easily, but the
material to be sifted is carried away by the current of air before and while it falls
on the beaters, the air thus offering a certain amount of resistance to the beaters or
fans and escaping through the holes or slits. The material, therefore, is not
properly thrown against the sifter.
The present improvements are illustrated by Figures I to XV; Fig. I being a
longitudinal section of the bolting-machine; Fig. II an end elevation of the same,
with a partial section of the sifting cylinder;, Fig. III represents in detail a
portion of the aifting cylinder; Figs. IV, V and VI are modifications in the
shaking mechanism for the sifting-cylinder; Figs. VII to XIV represent various

page_text: kinds of beater fittings, and Fig. XV shows a sifting cylinder provided with air
conduit.
The cylinders of bolting-machines make about 20 to 40 revolutions, and the
beaters 200 to 350 in a minute.
The carrier C of the beaters is fixed to the shaft m. The cylinder and the shaft
are supported by suitable bearings and driven by means of pulleys or tooth gear.
The outer casing of the cylinder is made of wood as usual.
The beaters or fans of such bolting-machines are made of corrugated sheet iron,
thus forming grooved or scooped beaters.
Owing to the conformation of these beaters, the material to be sifted falls in the
direction of the grooves and cannot escape at the sides, but, on the contrary, is
guided by the edges of the grooves, and, therefore, thrown in a radial direction
against the sieve.
The grooves of consecutive beaters may be placed in alternation with the
intermediate spaces so that, for instance, the material which is in the path of the
current coming from the opening a Figs. VII to XIII, is caught by the groove b of
the following beater and thrown against the silk gauze.
Figs. VII and VIII represent beaters consisting of long bars c with grooved or
channelled pieces b riveted on to them, whereas Figs. IX to XI represent beaters
made of corrugated sheet-iron, and Figs. XII and XIII beaters, in which the
edges b¹ of the channels are formed by slitting and bending up the sheet iron
itself.
In order to make the material move forward in the bolting machine, the sides b¹
of the grooves may be somewhat oblique, as shown at 2, Fig. XIV, so that the
material is constantly forwarded from the inlet p to the outlet q.
In cases where the material is to be driven through the machine more rapidly,
the beaters form a helical line round the axis, the said line having more or less
pitch according to the purpose for which the bolting machine is required.
The cylinder of the present centrifugal bolting-machine is star-shaped, and each
segment of the frame forms a right or a somewhat obtuse angle, over which the
silk gauze is stretched, as seen in Figs. I, II and III.
The two ends d of the cylinder A are provided with a star-shaped rim g, upou
which the angular frame-pieces e are laid and fastened.
This arrangement of the cylinder presents the important advantage that the
material is twice sifted, for it is thrown by the beaters i against the sifting
surface f and on leaving f it falls on to the sifting surface f¹, where it is sifted a
second time.
From f¹ the material falls again on to the beaters, and so on. Owing to the
construction of the sifting barrel cylinder the circumference of the latter serves as
a scoop wheel for all the material which falls to the bottom while the machine is
at work or standing still, and the material falls again on to the beaters on the
ascending side, which throw it once more against the sifter.
Moreover, owing to the peculiar outline of the sifters, the sifting surface f is
perpendicular to the direction in which the material is thrown by the beaters,
whereby the process of sifting is performed more rapidly and the sifter suffers less,
a larger sifting area is also obtained by the addition of the surface f¹.
No undue pressure of air can take place in this cylinder, especially as any slight
difference in the pressure which might be produced by such beaters would be very
advantageously compensated by the sifting surface f¹.
By this arrangement of the beaters, the material is duly thrown against the
sieve and sifted in the completest manner by means of the cylinder owing to the
reciprocal action of the machine.
To prevent the meshes of the sifter from becoming clogged, the cylinder A is
provided with toothed rims g, as shown in Figs. I, II, IV and XV; these gear
direct with small spur-wheels h, and in order to increase the vibration of the
cylinder, the toothed-wheel g or the spur-wheels h can be provided with a few
teeth longer than the others.

page_text: On the sides the cylinder is guided and supported by friction rollers / running on
rims or flanges. In Figs. I, II IV and XV the cylinder runs on each side on one
or two spur wheels, but in Fig. V the terminal discs d' of the cylinders have
excentric recesses or notches, and run on circular discs h¹, while in Fig. VI the
cylinders have circular end discs d running on excentric or recessed rollers h¹¹.
All these devices cause vibrations of the cylinder and thereby remove any
obstructions from the apertures in the sifting surface. m is the axle of the
beaters supported in bearings of the frames or plates 8, 8¹. The axle n of the
rollers or spur wheels may be driven from m in any suitable manner, and may
carry a transporting helix for the removal of the material which has fallen into
the collecting chamber. p is the feed-hopper, and q the discharge opening.
As a further means of keeping the meshes of the sifting surface free from
obstructions (especially for the sifting of soft and flaky material) an air conduit is
arranged as follows:-
Supposing for example the sifting surface to be round as represented by Fig. XV,
the blast pipe w situated outside the cylinder is provided with nozzles so placed
with regard to the cylinder, that they blow off the ground material adhering to
the latter, whereby the said material falls into the outer collecting chamber of the
cylinder. Other nozzles t, however, are directed more towards the centre of
the cylinder, whereby the coarse particles, which clog the inside of the sifting
surface, are blown off towards the inside.
The blast pipe w receives a longitudinal to-and-fro motion by means of a crank
disc or other suitable means.

page_text: Improvements in Bolting or Sifting Machines.
I, HERBERT JOHN HADDAN, of 67 Strand, in the City of Westminster, Civil
Engineer, do hereby declare the nature of this invention, a communication to me
from abroad by the firm of Escher, Wyss and Company Engineers, of Ravensburg,
in the German Empire, and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:—
The construction of bolting machines, shown by the accompanying drawing, is
superior to the bolting machines hitherto used, by requiring less motive power, and
by its rational manner of action.
The beaters, used until now in centrifugal sifting machines, consist ordinarily of
strips of sheet metal, either smooth or slightly curved in the direction of their
length.
Such arrangements involve the great disadvantage, that the beaters produce
a strong current of air and thereby also a strong air-pressure against the cloth
covering of the cylinder (like fan-blades). Consequently such sifting machines
absorb much force and, moreover, clog the cloth covering of the cylinder with
particles of the ground material, larger than the openings of the gauze; conse-
quently they prevent the passage of the fine particles of ground material and
of flour, while the coarser and heavier particles of the ground material are driven
about the gauze by the air current circulating with the wings, and rub the silk
gauze covering of the cylinder quickly through.
The second sort of beaters, namely those which are provided with holes or slots,
work more easily; the ground material however is taken along by the air previous
to and during its falling down upon the beaters, which air exerts a certain
resistance against the wings or beaters and escapes through these holes or slits;
the ground material, therefore, is not regularly cast against the gauze by such
beaters.
The improvements, intended to diminish such drawbacks, are graphically repre-
sented by Figs. I to XX of the annexed drawings.
Fig. I is a longitudinal section of a sifting machine embodying some of my
improvements.
Fig. II a side view of the same with partial section of the bolting cylinder.
Fig. III illustrates a detail of the bolting cylinder.
Figs. IV and V show modifications thereof.
Fig. VI is a side view of the sifting machine, with a modification of the hopper
or shaking movement.
Figs. VII and VIII indicate further modifications of the hopper movement.
Figs. IX to IXX are longitudinal sections and views of details of various forms
of beaters.
Figs. IX, XII and XVI are longitudinal sections showing that the mountings of
any two consecutive beaters are placed out of line with each other.
Figs. IX to XVIII show the mountings in approximately natural size.
Fig. IXX is a modification of the beater-mounting, shown in Fig. L

page_text: 1
Fig. XX shows the manner of applying an air-conduit to the cylinder of the
sifting machines.
The cylinders of sifting machines make about 20 to 40, the beaters or wings 200
to 350 rotations per minute.
The beater-cross or -carrier C is fastened on the axle m. The cylinder and axle
are lodged in suitable bearings and are actuated by pulleys or wheels. The outer
lining of the cylinder consists of the usual wooden casing. The wings of the afore-
mentioned sifting machine are made of perforated corrugated sheet metal or of
beaters provided with rows of dished plates or grooves; owing to these grooved
beaters, the ground material proceeding in the direction of the groove, cannot
escape laterally, but is conducted by the groove-edges 61 and therefore thrust
regularly and in radial direction against the gauze. The grooves of any one beater
are out of line with those of the contiguous beaters, so that, for instance, the ground
material, which is situated in the direction or line of motion of the intermediate
openings a, Figs. IX to IXX, is seized by the groove b of the following beater and
thrown against the silk gauze.
While Figs. IX to XI show parts of beaters, formed by longitudinal bars c and
grooved cross rails b riveted thereon, Figs. XII to XVI show beaters of perforated
corrugated sheet iron; Figs. XVII and XVIII show parts of beaters, in which the
rims 6 are bent upward from the level of the metal strips, after the latter have
been slotted. To accelerate the passage of the ground material through the sifting
machine, the groove rims b¹ of the beaters can be slightly oblique, as for instance in
beater, Fig. IXX, and that so, that the sifting material is forwarded from the
inlet p to the outlet passage q Fig. I. In case the sifting material is to be driven
still more rapidly through the sifting machine, the beaters form a screw line around
the axis of the cylinder, which line has more or less twist according to the purpose,
for which the sifting machine serves.
The cylinder of the improved centrifugal sifting machine is somewhat star-shaped
in cross-section, and each frame-piece (or segment) forms a right or obtuse angle,
over which the silk gauze is stretched.
The two end discs d of the cylinder A are provided with a radiated or star-
shaped rim g in which the angular frame-pieces è are lodged and fastened.
The present arrangement of cylinder frames has the advantages, that the sieving
surface of the cylinder is situated perpendicular to the line of motion or throw
of the ground material, further that the ground material, as shown by Fig. II,
undergoes twice the process of sifting, for the ground material is thrown against
the sieving surface f¹ by the beaters c in C, and when falling down, it falls upon
the sieving surface f and is therefore again sifted through the latter.
By stretching a web over the rear wall f the tension of air in the cylinder
is diminished. From the back wall the ground material slides down again in
a divided state upon the beater. This cylinder, that is to say, its covering, serves
further as a scoop-wheel for the whole of the ground material, which has fallen on
the bottom, this material subsequently falling from the ascending side upon the
beaters, and being again thrown by the same against the covering.
Moreover, by this radiated or star-shaped covering of the sifting cylinder, the
sieving surface f' gets into a rectangular position to the line of thrust of the
beaters, that is to say, to the fly-direction of the sifting material, whereby
the sifting takes place more rapidly and the covering is less injured. By the
addition of the surface f the sieving surface is considerably increased.
A considerable tension of air in this cylinder can the less take place, as any
minute differences of air pressure, which may be produced by these new beaters,
can be very advantageously compensated by the sifting surface f. By these beater
arrangements, a regular thrust of the ground material, as well as a regular sifting
through the cylinder, is attained in a very complete manner by the supplemental
action of different parts.
If the ground material is to be still better distributed (although at the expense
of the advantages obtained by the sieving surface f) the construction may be

page_text: modified by making the backwall full, roughening it or providing it entirely or
partly with longitudinal ribs fo, which allow the ground material to fall at the
ascending side in a thin stream upon the beaters.
Such a modification is shewn by Fig. V. The slots or longitudinal grooves at
the backwall f, which are not exposed to the direct thrust of the beaters, are
parallel or slightly inclined to the axis of the cylinder, and that in the latter case
so, that, owing to the inclination of the ribs or grooves, the ground material, when
sliding down, falls from the inlet towards the outlet-side.
The grooves fo may also be so arranged, that the sifting surface f is retained,
as shown by Fig. IV.
To prevent the clogging of the meshes of the cylinder covering, the cylinder A,
as shown by Figs. I and II, is provided with toothed rings g, which run direct on
small spur-wheels h. To increase the shaking of the cylinder, either the toothed
rings or the spur-wheels h may be provided with a few extended teeth 2.
Laterally the cylinder A is guided by the rims 1, on which roll the guide pulleys k.
The arrangement of the shaking motion may also be suitably modified. Namely,
while Figs. I, II, IV and XX show arrangements, in which the cylinder runs at
each side on one or two spur-wheels, Fig. VIII shows an arrangement, in which
the head discs or end discs d' of the cylinders have eccentric recesses or steps and
run on round rollers h³, and Fig. VIII shows an arrangement with round head- or
end-discs d¹¹ and eccentric lower rollers h". All these arrangements cause shakings
and therefore serve to clear the openings of the cylinder covering.
In Fig. I, m is the driving axle for the beaters, supported in the shields 8 8, and
from which motion is at will imparted to the organs driving the cylinder, therefore
also to the wheel axles n. The axle n may be provided with an ordinary trans-
porting worm for the removal of the sifted material, which falls into the lower
collecting chamber; p is the feed hopper at one end of the sifting cylinder, q is the
outlet at the other end.
To further ensure the required cleanness of the meshes of the covering of the
sifting machines (especially in the case of soft and flaky sifting material) an air
conduit with differently directed outlet nozzles is employed.
The employment of this air conduit need not be combined with the shape
Fig. II, of the sifting cylinder. In Fig. XX for instance, the cylinder covering is
round; the air tube W arranged outside the cylinder is provided with nozzles r
which are so placed to the cylinder, that they blow off the flaky sifting material
adhering to the outer cylinder, whereby the said material falls into the outer
collecting chamber of the cylinder.
Further nozzles t, however, are directed more towards the axis of the cylinder;
thereby the coarse and the minute particles, which obstruct the openings (meshes)
at the inside of the cylinder covering, are blown off towards the interior.
By this arrangement of the air conduit a permanent purification of the covering
is obtained.
The air tube w may be advantageously moved to and fro along the cylinder,
(for instance by a crank disc).
Having now particularly described and ascertained the nature of this Inven-
tion and in what manner the same is to be performed, I declare that what
I claim is in Bolting machines
1.) Beaters, provided with radial or inclined grooves and with rims adapted to
serve firstly to guide the sifting material, secondly to throw the same radially,
and thirdly to break up the same (Fig. I IXX and IX to XVIII), the beater
strips e, a b c being either straight (that is to say parallel to the cylinder axis) or
twisted helically.
2.) Sifting-cylinders, star-shaped in cross section, and having the silk-gauze
mounted on angular frames so as to present two sets of sifting surfaces fand f¹,
without grooves fº (Figs I, II and III) or with grooves fº (Fig. IV).

page_text: 3.) Sifting cylinders, star-shaped in cross section, provided with the angular
frames described, but so modified, that only the face fl serves as sifting surface,
while the face f is solid (closed) and roughened, or provided wholly or partly with
longitudinal ribs or longitudinal grooves fo, Fig. V, in lieu of the roughening.
4.) Longitudinal beater surfaces fº placed at a slight angle to the cylinder-axis,
in such a manner, that the ground material, when sliding down, is guided by the
ribs or grooves from the inlet towards the outlet side.
5.) The mechanism for producing the rotary and shaking motion of sifting
cylinders, chiefly comprising spur-wheels (or cams or equivalent,) and toothed rims
or cam rings secured to the end frames of the sifting cylinder and resting on the
said wheels or cams, as illustrated by Figs. I, II, VI VII and VIII.
6.) The combination of a sifting cylinder, with an air or blast pipe W, situated
outside of the said cylinder and provided with discharge-tubes adapted to blow
off the flour in an outward direction from the cylinder covering, and with discharge
tubes t adapted to blow towards the inside the ground material adhering to the
inner surface of the covering, as illustrated by Fig. XX.
211
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