Improvements in Plan-sifters.
Year: 1899

page_text: PROTIONAL DIECIFICATION.
Improvements in Plan-sifters.
I, GERHARD ZARNIKO, of 10, Bahnhossplatz, Hildesheim, in the Empire of
Germany, Engineer, do hereby declare the nature of this invention to be as
follows:
This invention has for its object an improved plansifter.
The material to be sifted, as is shown by observation, in addition to a circular
movement executes the following progressive movements on a surface swinging
with a plansifter motion when said material comes in contact with curved vertical
or approximately vertical walls:
1st. A retrograde movement, that is to say a movement in an opposite direc-
tion to the swing of the surface, if confined in a circular space.
2nd. A movement in a similar direction to the foregoing when in wide passages
or channels.
3rd. A movement coincident with the direction of. swing when in narrow
channels.
This tendency is utilized according to the present invention for obtaining a
plansifter progression of the material to be sifted on the swinging surface by
means of a suitable arrangement of curved walls. The simplest arrangement
for this purpose consists in forming passages or channels with a zig-zag or sinuous
course of alternate wide and narrow tracks that is to say a wide track running
to the right opening into a narrow track to the left and so on so that the material
to be sifted travels in the wide passages to the right (in the opposite direction
to the direction of rotation) and in the narrow passages to the left (in the same
direction as the movement of rotation) and thus travels from the inlet to the
outlet. The same action takes place in the arrangement if the wide passages be
given almost a circular form.
In a similar way walls may be arranged so that the material to be sifted is
brought from the centre to an outlet near the edge, narrow passages being
arranged to forward the material in the direction of the hands of a watch, and
circular spaces and broad passages to forward it in the opposite direction.
Of course the most varied arrangements are possible and any other devices
suitable for and possible in sieves may be combined therewith (collecting floors,
brushing devices, arrangement of several sieves one above the other, and the
like).
The explanation of the appearance herein before utilized may perhaps be
found in the following facts:-
If vertical circular walls be arranged on a surface swinging with a horizontal
parallel movement in a closed course (plan sifter movement) and if the chamber
enclosed by such an annular wall be filled with material to be sifted the material
assumes a movement leaving a sickle shaped space constantly circulating in
such a way that it has the appearance as if an approximately circular disc formed
of material to be sifted and of somewhat smaller diameter than the circular
surface of the annular wall, were waltzing round within the latter. This

page_text: travelling takes place in the direction of the swinging movement whether the
said travelling of the whole mass or of its centre be regarded; the points of.
the periphery however describe a retrograde (epicycloidal)" .course, just as if
the layer of material to be sifted were an actual disc.
In circles travelling one in the other as is well known the kind of movement
depends on the proportions of the diameters in such a way that a retrograde
movement only takes place when the inner circle is greater than the half dia-
meter of the outer one, but that a forward progressing movement of the peripheral
points takes place when the inner circle is smaller than the half diameter of
the outer. In the present case a scale for the proportion of the diameters may
be constituted in the following way
1
The width of the sickle (space) .e. the excess diameter of the outer rotating
disc over the material to be sifted, depends on the size of the diameter of the
crank circle which gives the cue for the movement of all the points of the swing-
ing surface. This however remains the same and with it' also the width of the
sickle, whatever may be the diameter of the outer ring. It follows therefrom
that in a large circle the ratio of the diameters approaches 1, whilst in a smaller
one, it retrogrades from 1.
Improvements in Plan-sifters.
I, GERHARD ZARNIKO, of 10, Bahnhossplatz, Hildesheim, in the Empire of
Germany, 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:-
This invention has for its object an improved plansifter and is shown in the
accompanying drawings.
The material to be sifted, as is shown by observation, in addition to a circular
movement executes the following progressive movements on the surface A, in
Figure 3, swinging with a plansifter motion when said material comes in con-
tact with curved vertical or approximately vertical walls:-
1st. A retrograde movement, that is to say a movement in an opposite direc-
tion to the swing of the surface, Figure 3, if confined in a circular space B. "
2nd. A movement in a similar direction to the foregoing when in wide pas-
sages or channels C and D.
'
3rd: A movement coincident with the direction of swing when in narrow
channels beside D.
-
This tendency is utilized according to the present invention for obtaining a
plansifter progression of the material to be sifted on the swinging surface by
means of a suitable arrangement of curved walls. The simplest arrangement
for this purpose is shown in Figure 4 and consists in forming passages or chan-
nels a and b with a zigzag or sinuous course of alternate wide and narrow tracks,
that is to say a wide track a running to the right opening into a narrow track b
to the left and so on so that the material to be sifted travels in the wide pas-
sages a to the right (in the opposite direction to the direction of rotation) and
in the narrow passages 6 to the left (in the same direction as the movement of
rotation) and thus travels from the inlet E to the outlet Z. The same action

page_text: takes place in the arrangement if the wide passages be given almost a circular
form as shown in Figure 5.
In a similar way as shown in Figure 6, walls may be arranged so that the
material to be sifted is brought from the centre E to an outlet Z near the edge,
narrow passages being arranged to forward the material in the direction of the
hands of a watch, and circular spaces and broad passages to forward it in the
opposite direction.
Of course the most varied arrangements are possible and any other devices
suitable for and possible in sieves may be combined therewith (collecting floors,
brushing devices, arrangement of several sieves one above the other, and the
like).
-
The explanation of the appearance hereinbefore utilized may perhaps be
found in the following facts:-
If vertical circular walls be arranged on a surface swinging with a horizontal
parallel movement in a closed course (plan sifter movement) and if the chamber
enclosed by such an annular wall be filled with material to be sifted, the material
assumes a movement leaving a sickle shaped space constantly circulating in
such a way that it has the appearance as if an approximately circular disc formed
of material to be sifted and of somewhat smaller diameter than the circular
surface of the annular wall, were waltzing round within the latter, see Figure 1.
This travelling takes place in the direction of the swinging movement whether the
said travelling of the whole mass or of its centre be regarded; the points of
the periphery however describe a retrograde (epicycloidal) course, just as if
the layer of material to be sifted were an actual disc.
In circles travelling one in the other as is well known the kind of movement
depends on the proportions of the diameters in such a way that a retrograde
movement only takes place when the inner circle is greater than the half dia-
meter of the outer one, but that a forward progressing movement of the peripheral
points takes place when the inner circle is smaller than the half diameter of
the outer (see Figure 2). In the present case a scale for the proportion of the
diameters may be constituted in the following way.
The width of the sickle (space) in Figure 1 i.e. the excess diameter of the
outer rotating disc over the material to be sifted, depends on the size of the
diameter of the crank circle which gives the cue for the movement of all the
points of the swinging surface. This however remains the same and with it
also the width of the sickle, whatever may be the diameter of the outer ring.
It follows therefore that in a large circle the ratio of the diameters approaches 1,
whilst in a smaller one, it retrogrades from I.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what I
claim is:
A forwarding device for sieves or collecting trays in plansifters having a
parallel movement, characterised by a progressive movement of the circulating
material being obtained by a division of the swinging surface into narrow and
wide passages or channels with curved or bent walls and into open circular, or
the like, spaces, in such a way that the material moves forward in the narrow
passages in the direction of the swing, but in an opposite direction in the wide
passages and the open circular, or the like, chambers, substantially as herein-
before described.
1000
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.