Purification of Sugar-liquor.
Year: 1886

page_text: Purification of Sugar-liquor.
I, WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake & Co, Patent Agents,
Southampton Buildings, London do hereby declare the nature of my invention
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
In continuous filters for effecting the purification of sugar liquor by the process
of upward filtration through bone black, the bone black at the bottom of the
filtering chamber requires to be gradually removed as it becomes charged with
impurities and loses its decolorizing power, and a quantity of fresh bone black
equal to that removed is at the same time introduced into the top of the filtering
chamber.
This invention relates to apparatus designed for employment in a continuous
filter for the purpose of effecting the removal of the exhausted bone black from the
bottom of the filtering chamber containing a column of bone-black through which
the sugar-liquor to be purified is forced in an upward direction; and the invention
consists in providing a rotating bottom for the filtering chamber, composed of a
slightly conical frame supporting a cutting blade arranged in the form of a conical
helix, the convex edge of each convolution of which blade, successively overlaps
the concave edge of the next adjoining convolution; the spaces between the
successive convolutions and the extent of overlapping, being arranged to prevent
the superincumbent bone black from falling through the spaces between the con-
volutions merely under the influence of its own gravity, so that there will be no
fall of bone-black through the discharger into the receiving chamber, excepting
when the discharger is rotated for the purpose of effecting the discharge of a
prescribed quantity of bone-black from the bottom of the column.
In the accompanying drawing showing a continuous filter containing the
improvements.
Figure 1 is a central longitudinal section.
Figure 2 is a horizontal section on the line x, x, Figure 1.
Figure 3 is a central vertical section taken on the line y, y, Figure 2, illustrating
a modification of the arrangement of the cutting blade, which consists in having
each convolution of the blade canted inwardly and downwardly from its outer
edge.
Figure 4 is a section similar to Figure 3, showing the convolutions of the
cutting blades so arranged as to cant outwardly and downwardly from their
inner edges

page_text: Figure 5 is a central vertical section of the discharger modified by having
the convolutions of its shearing blade gradually descend from the circumference
to the centre.
The characteristic features of the continuous filtering apparatus illustrated in
the drawings are the filtering chamber A, surmounting the receiving chamber B;
the well C containing the chain-and-bucket elevator D, for effecting the removal
of the exhausted bone-black from the receiving chamber, the service pipe E, for
supplying the sugar-liquor to be purified under sufficient head to enable it to make
its way upward from the receiving chamber through the column of bone-black
in the filtering chamber to the outlets A¹ through which it is discharged from the
filtering chamber.
The column of bone-black F in the filtering chamber is supported at the bottom
upon the top of a helically coiled cutting or shearing blade G, which is mounted on
the frame G₁, affixed to the vertical shaft G² to which power is applied for the
purpose of rotating the discharger. Whenever the necessity arises for the removal
of the exhausted bone-black from the bottom of the filtering chamber, the discharger
is rotated, and a stratum of bone-black of uniform thickness is thereby sheared
from the lower end of the column, and forced through the spaces between the
convolutions of the shearing blade.
When thus discharged, the exhausted bone-black falls down the inclined bottom
of the receiving chamber B to the lower end of the well C, and is caught and
carried up by the buckets D¹ of the elevator, and discharged upon the inclined
chute D2 at the top of the well.
The buckets D are perforated, or made of wire-gauze, in order that the sugar-
liquor may to some extent drain out of them before they discharge their contents
upon the chute.
The chain-and-bucket elevator and other contrivances which have been here-
tofore devised for removing the exhausted bone-black from the bottom of the
receiving chamber without interrupting the continuity of the filtering operation do
not constitute any part of the present invention, and are equivalent elements, either
of which is a recognized appurtenance of a continuous filter.
The shearing blade may be arranged in the form of a spiral plane, gradually
ascending from the circumference to the centre of the filtering chamber, as shown
in Figure 1, or descending from the circumference to the centre, as shown in
Figure 5. The various convolutions H, H of the shearing blade may also be
canted inwardly and downwardly as shown in Figure 3, or the shearing blade
may have its convolutions I, I canted outwardly and downwardly, as shown in
Figure 4. If, however, the convolutions of the shearing blade are canted in either
direction, they must be so proportioned and arranged as to more widely overlap
each other than when arranged in the form of a spiral plane, as illustrated in
Figure 1.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, as communicated to
me by my Foreign Correspondent, I declare that what I claim is :-
In a continuous filter, a bone-black discharger consisting of a shearing blade
arranged in the form of a conical helix, the convolutions of which overlap and are
separated from each other to a prescribed extent; a suitable frame for supporting
the shearing blade; and means for imparting rotary motion to the discharger upon
its vertical axis, as, and for the purpose, set forth.
Dated this 9th day of February 1886
HASELTINE, LAKE & Co.,
For the Applicant.