Improvements in Flour Sifters.
Year: 1892

page_text: Date of Application, 29th Mar-, 1892-Accepted, 21st May, 1892
COMPLETE SPECIFICATION.
Improvements in Flour Sifters.
I, PETER JENSEN of 77 Chancery Lane London Chartered Patent Agent do
hereby declare the nature of this invention (a communication from Nestor
Reinicke of Geislingen, Germany, Mechanical Engineer) and in what manner the
same is to be performed to be particularly described and ascertained in and by
the following statement:―
This invention has for its object improvements in the construction of machines
for sifting flour and more especially to provide new means by which the flour is
agitated on the screens in such a manner, that it is gradually moved forwards
from one end of the screen to another. The invention also consists in combinations
of parts and in the specific construction of several parts as will hereinafter be
more particularly specified.
Fig. 1 is a longitudinal section of a sifting machine embodying my invention.
Fig. 2 is a cross section through the same and
Fig. 3 is a horizontal sectional view.
Fig. 4 shews a detail.
The framework A of the machine is shown as made in wood, and between the
wooden posts there are nailed or otherwise secured panels a, the whole forming a
box or casing around the sifting apparatus. This latter consists of one or more (in
the drawing 4) horizontally arranged screens mounted in frames B. The arrange-
ment of the screens in the frames and the construction of these parts may be made
in different ways, as the principal part of this invention consists in the peculiar
way of supporting the screen frames. As will be seen from the drawing the
frames B are connected with each other by means of braces C, of which two on
each side connect the first and the third frame and two on each side the second and
fourth frame. If the sifter has only two screens these braces are not necessary of
course, and if there are more than 4 screens for instance 6 the braces will connect 3
and 3 screen frames with each other. To each of the braces is fixed a pin c and to
the framework of the enclosing box is by some suitable means secured a number of
spring arms D, having at their ends an eye d in which the pins c are inserted so
that the screen's (two and two) will be supported by these spring arms only. The
said spring arms are secured in an inclined position and for one set of screens they
fall off to the left and for the other set of screens they fall off to the right. A
preferable way of mounting these springs is shown in detail in Fig. + consisting
in securing to the framework standards or brackets D', which are provided with a
curved slot d', the centre of which is at c and to these brackets are by means of
bolts entering the slots secured adjustable plates D" having a lug or rib d" to
which the foot of the springs D are fastened. By these means the spring may be
adjusted for different angles according to the circumstances.
On top of the machine is placed a shaft E working in bearings e, one on each
side of the machine. This shaft may of course also be placed at the base of the
machine or between two screen frames. The shaft is provided with three
excentrics on cranks f, f¹ and f*, which by means of straps and rods F, F, F" are
connected with the screens or frames; the rods F¹ and F" embracing with their
lower ends pins y secured to braces G, that connect the second with the fourth
screen-frame, and the rod F is connected to a pin h, which rests in a forked lug H
on the top of a brace G¹ across the side pieces of the uppermost screen frame.
The shaft E is rotated by means of a pulley or in any other suitable way and
through the eccentrics or cranks and rods, this rotary motion is transformed into a
vibratory motion, so that the screens will be agitated.

page_text: As however the springs, supporting the screen frames are not mounted hori-
zontally but inclined, the screens will vibrate at right angles to the direction of the
springs and from this reason the particles resting on the screens will not be thrown
right upwards but under an angle, so that they for each vibration of the screen
will jump forwards and always in the same direction. On the first (upper) and
third screen, they will therefore move to the left and on the second and fourth they
will move to the right (as indicated by arrows).
I will now proceed to explain the special arrangement of the screens, shewn in
the drawings. The screens are held to the screen frames in the usual way by
means of wooden frames and to the lower side of the screen frames is fixed a
bottom B preferably of sheet metal. The upper frame has an outlet 1, on the
left end above the screen through which the largest particles find their way out.
The rest of the flour gathers on the bottom B₁ and finds its way down to the next
screen through the shoot 2. Through this screen only the finest particles can get
down on the bottom B' of this frame and from the right end of this latter bottom
a shoot 3 leads down to the space between the screen and the bottom plate of the
third screen, from which space at the other end of the screen a shoot 4 is placed
and through this shoot the finest quality of flour passes out.
The flour remaining
on the upper side of the screen of the second frame is led through the shoot 5
down to the third screen and the flour remaining at the other end of this latter
screen passes down through the shoot 6 to the fourth screen. The flour passing
through the first part of this screen is led out through the shoot 7 at the centre of
the screen and the flour passing through the other part through the shoot 8 at the
right end of the screen, while the flour remaining on the screen gets out through
the shoot 9.
K are small shafts put across the screen frames and carrying at the centre a
double arm k with cushion pieces k¹ at the ends and on one end the shafts carry a
counterweight. These shafts with their arms are arranged close below the
screens at such distance from the same that the shafts may rock a little when the
screens vibrate and thereby knock off the flour that may stick to the screens.
The same end may also be reached in other ways for instance by making the rods
connecting the cranks of the shaft E with the screen frames in two pieces and
uniting these pieces by means of a coupling in which one of the rod ends has
a little play, say about th or inch whereby the screens will receive small
shocks.
The advantage gained by supporting the screens or screen frames ou inclined
spring arms and imparting to the screens a vibratory motion by means of a motor
acting in a direction that is vertical or nearly so relatively to the plan of the
screens, compared with arrangements hitherto used in which the screens are
agitated in a horizonal plane or nearly so under the action of a motor acting in a
horizontal plane, is that in the latter case the largest and beaviest particles will
mostly gather directly on the screen while the lighter particles will remain on the
top of the larger ones the result being, as will be easily understood, that the small
particles will be hindered from dropping through the screen. When however the
arrangement is as above described, the larger and heavier particles will be thrown
upward through the top layer and making longer jumps than the small particles,
will use less time than these in passing from one end of the screen to the other, so
that the small and lighter particles will mostly remain in direct contact with the
screen and therefore pass through the same quickly. Besides this the vertically
acting shocks will act to loosen the particles, which may be sticking to the screen,
while horizontal shocks will have just the opposite result. As will be easily under-
stood, the crank shaft need not be placed above the machine it may also be placed
below the same or in the middle between two screen frames, and instead of cranks,
excentrics may be used or cam wheels or the like. Furthermore the screens
may be arranged otherwise, for instance so that each frame has two or more
screens.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In a flour sifting machine the combination with screens supported hori-
zontally or nearly so on springs that are mounted in an inclined position of a
rotating shaft imparting vibratory motion to the screens by means of cranks,
excentrics, cams or equivalent means acting vertically or nearly so against the
plane of the screens.
2. In a flour sifting machine the combination with the screens of rock shafts K
being supported by the screen frames below the screens and carrying arms & the
ends of which may come in contact with the screens and also carrying a counter-
weight that imparts a rocking movement to the shaft when the screens
vibrate.
3. In a flour sifting machine the combination with the spring arms D of
standards D carrying the same and being provided with curved slots d¹ for
purposes substantially as specified.
4. A sifting machine constructed substantially as shown and described.
Dated this 29th day of March LANZ
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.