IMPROVEMENTS IN AND RELATING TO BONE-BLACK FILTERS FOR FILTERING SUGAR LIQUOR
Year: 1885

page_text: Sugar Liquor.
I, WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake & Co Patent Agents,
Southampton Buildings, in the County of Middlesex do hereby declare the nature
of my invention for "IMPROVEMENTS IN AND RELATING TO BONE-BLACK FILTERS
FOR FILTERING SUGAR LIQUOR" and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement :-
This invention relates to bone black filters for filtering sugar liquors.
In bone black filters for filtering sugar liquor by the process of upward filtration,
the lowest stratum of bone black is that which soonest becomes exhausted; and
the object of my invention is to provide for the gradual and uniform removal of the
lowest stratum of bone black without causing any violent falling movement of the
superincumbent mass of bone black, so that concurrently with the removal of
the exhausted bone black, fresh bone black can be introduced into the top of the
filter where the filtered sugar liquor is discharged; and my invention consists in
supporting a mass of bone black in a filter chamber upon the uppermost convolution
of a screw rotating upon vertical axis or upon the upper surface of a suitable
perforated or slotted rotating disc provided with a shearing blade or blades. By
the rotation of the said screw, or the said disc, the exhausted bone black is
gradually removed, or cut off, from the lower end of the mass of superincumbent
bone black and allowed to fall into a receiving chamber from which it is removed
by any convenient means as for example a screw conveyor or conveyors.
In the accompanying drawing which represents my improvements, in the form in
which I prefer to employ them, applied to a bone black filter provided with an
elevator screw encased in a suitable tube for removing the exhausted bone, black
from the bottom of the filter or receiving chamber:-
-
Figure 1 is a central vertical section through the filter and elevator tubes.
Figure 2 is a horizontal section on the line a, a Figure 1, showing the top of the

page_text: Figure 3 is a vertical section of the discharger taken through the line y, y on
Figure 2.
In the filter shown in the drawing, the principal body of bone black A is con-
tained in a large vertical cylinder B, and rests at the bottom upon the discharger E,
beneath which is the receiving chamber a into which the exhausted bone black is
caused to fall by the action of the discharger E.
From the receiving chamber the exhausted bone black is removed by means of
the inclined elevator screw C encased in the inclined tube C¹, the upper end of
which is provided with the chute C, upon which the spent bone black, elevated by
the screw C, falls by its own gravity.
The sugar liquor to be filtered, introduced into the upper part of the inclined
tube C¹ by means of the supply pipe D, falls through the inclined tube C¹ into the
receiving chamber, and rises by hydrostatic pressure through the mass of bone
black contained in the filtering chamber B, and is discharged through suitably
screened openings from the upper part of the chamber B.
The discharger in the form which I prefer, consists of a horizontal disc E affixed
to the central vertical shaft El; which is provided with a suitable bearing at the top
of the filter and projects therefrom, and is provided with a pulley or toothed
wheel E by means of which power is imparted to rotate it.
The lower end of the vertical shaft E' is provided with a bearing upon the upper
surface of the horizontal beam F, which extends across the receiving chamber and
is secured to the side wall thereof, and which has its central portion supported by
the inclined braces F¹, F
In the case of a filter, and consequently of a discharger, of large diameter, it will
be desirable to support the rim as well as the centre of the discharger. This may
be effected by means of conical rollers g, g, g, &c which have their axes radially
arranged, and are provided with bearings in a circular frame G, securely fastened
to the interior wall of the filter cylinder B. The under surface of the rim of the
discharger is slightly chamferred, as shown, and bears upon the tops of these conical
rollers.
The discharger E is provided with a series of openings 6, extending from its
central portion outward nearly to its perimeter. These openings, are so far inclined
as to prevent the bone black from running through them merely by its own gravity,
and their upper edges constitute the shearing blades e¹, which, when the discharger
is rotated in the direction of the arrow shown in Figure 2, shear or scrape the bone
black from the lower surface of the mass of bone black contained in the filter
chamber B, and thus cause it to be forced through the inclined openings e, from
which it falls into the bottom of the receiving chamber a
When the elevating screw is employed for removing the spent bone black from
the receiving chamber a, the latter is preferably made in the form of an inverted
cone, the lower end of which is united to the lower part of the inclined tube or
cylinder C¹, in which the elevator screw C is contained.
In operation, after the apparatus has been filled with sugar liquor, the rate at
which the sugar liquor is introduced through the supply pipe D, and consequently
the rate at which it is discharged from the upper part of the chamber B, is
graduated with reference to maintaining the sugar liquor in contact with the bone
black for the length of time required to perfectly decolorize it; the speed of
rotation of the discharger is also regulated with reference to effecting the uniform
and gradual removal of the exhausted bone black from the lower part of the mass
of bone black contained in the chamber B as rapidly as the bone black at that
point becomes exhausted, fresh bone black being fed into the upper end of the
chamber B, at a rate corresponding to that at which the exhausted bone black is
removed.
By this means, the operation of filtration is performed continuously, and all the
sugar liquor passed through the filter is subjected to like conditions, both as to
duration of contact with bone black and as to contact with bone black which is not
exhausted.

page_text: At the same time there is no violent disturbance of the mass of bone black,
sufficient to materially disturb the current of sugar liquor or interfere with the
efficient decolorizing action of the bone black.
Having now particularly described and ascertained the nature of the 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
First. In a bone black filter for filtering sugar liquor by the process of upward
filtration, a filtering chamber having at the bottom a discharger in the form of a
screw or slotted disc provided with a shearing blade or blades, and means for
rotating said discharger for the purpose of gradually removing the exhausted bone
black from the bottom of the mass of bone black contained in the filtering chamber,.
in combination with a receiving chamber for receiving said exhausted bone black
and means for removing the said exhausted bone black from the said receiving
chamber, substantially as set forth.
Second. A filtering chamber for containing bone black, having arranged beneath
it a receiving chamber, and provided with means for the gradual lowering of the
bone black from the filtering chamber into the receiving chamber, in combination
with an inclined elevator screw contained in a correspondingly inclined tube for
removing the exhausted bone black from the receiving chamber, substantially as
set forth.