Improvements in Filtering Apparatus for rullying suga
Year: 1886

page_text: Improvements in Filtering Apparatus for rullying suga
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 this 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 purifying sugar-liquors 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.
To properly effect such removal is the object of the present invention, which
consists, broadly, in the combination with the filtering apparatus, of a bottom for
the filtering chamber in the form of a stationary grate provided with rocking slats
or grate-bars, and means for rocking the said slats or grate-bars to and fro, for the
purpose of alternately opening and closing the spaces between the grate-bars and
thereby either holding back the bone-black in the filtering-chamber, or permitting
it by its own gravity, to fall through between the grate-bars, into the receiving
chamber beneath the filtering chamber.
The invention also embraces grate-bars of a certain peculiar form in cross-section,
as hereinafter set forth.
In the accompanying drawing illustrating the invention
Figure 1 is a central vertical section of a continuous filter, for effecting the
purification of sugar liquor by the process of upward filtration through bone-
black, provided with this improvement and shewing the rocking grate-bars in the
positions in which they are brought to rest at the end of their backward motions.
Figure 2 is a horizontal section on the line x, x Figure 1, shewing a top view of
the grate.
Figure 3 is a vertical section on the line y, y Figure 2 shewing one of the grate-
bars in side elevation, and shewing the bearings for its trunnions in the two parallel
horizontal girders which constitute the grate-frame.
Figure 4 is a vertical section on the line z, z Figure 2, shewing a side elevation
of one of the girders in which the trunnions of the grate-bars have their bearings,

page_text: and the positions which they occupy after they have completed about one quarter
of their forward movement.
Figure 5 is a transverse vertical section, of several adjoining grate-bars, shewing
them in the positions which they occupy after having completed one half of their
rocking motion in either direction.
Figure 6 is a similar section, shewing the positions which the grate-bars occupy
when they have completed about three quarters of their forward rocking move-
ment; and
Figure 7 is a similar section shewing the positions in which the grate-bars are
brought to rest at the conclusion of their forward motion.
In the type of filtering apparatus to which this invention relates, a filtering
chamber A, surmounts a receiving chamber B.
The sugar liquor to be purified is introduced into the receiving chamber under
sufficient head to enable it to make its way upward through the column of bone-
black in the filtering chamber to the outlets C, through which it is discharged.
From time to time as may be required quantities of exhausted bone-black are
removed from the bottom of the filtering chamber into the receiving chamber, and
like quantities of fresh bone-black are fed into the top of the filtering chamber.
Provision is made for the removal of the exhausted bone-black from the receiving
chamber without interrupting the continued upward flow of the sugar liquor in the
filtering-chamber.
These are the typical characteristics of various forms of apparatus which belong
to the class of so-called continuous filters.
Figure 1 of the drawings shews one of the well-known methods of removing the
exhausted bone-black from the receiving chamber. This consists of a tube or
well D provided with a chain-and-bucket elevator d. The exhausted bone-black
flows down the inclined bottom B¹ of the receiving chamber into the bottom D¹ of
the well, and is elevated therfrom by being caught in the buckets d' which are
made of wire gauze, or are perforated, so that the sugar-liquor may be to some
extent drained out of them before they reach the top of the well at which point
their contents are discharged upon the chute D.
The sugar liquor to be purified is introduced into the upper part of the well
through the service pipe E, which is connected with a suitable reservoir.
The bottom of the filtering chamber consists of a series of equidistant horizontal
grate-bars F, F. Each grate-bar is provided at its opposite ends with trunnions f,
bearings for which are provided, respectively, in two horizontal girders G, which
are fastened in any convenient way in the upper part of the receiving chamber B
upon opposite sides thereof.
Equidistant semi-cylindrical grooves g are formed transversely across the top of
the girder G and similar semi cylindrical grooves gl are formed transversely across
the bottom of the cap piece G¹, which is bolted to the top of the girder G by means
of the screw-bolts G². The spaces between the semi-cylindrical grooves g and g¹
respectively constitute the bearings for the trunnions f of the grate-bars.
The grate-bars are provided at both ends with the downwardly projecting
crank-arms F1, F¹ and the crank-arms on each side are pivotted to the horizontal
connecting rods F2, F2, respectively.
Motion to rock the grate-bars may be transmitted from excentrics on the
horizontal crank-shaft I to horizontally sliding carriages, one of which, I', is
shewn in Figure 1, to which carriages the upper ends of the slide-rods 12 are
respectively connected. The slide rods extend through suitably packed bearings I³
in the wall of the receiving chamber, and upon their inner ends are connected by
links, one of which 1' is shewn in Figure 4, to the ends of the connecting rods F³ F³,
respectively.
Power to rotate the shaft I for the purpose of rocking the grate-bars, is applied
by means of gearing, or in any other convenient way.
It will be seen that the grate-bars may be rocked into positions in which they
entirely close the mouth of the filtering chamber, or into other positions in which

page_text: the spaces between them are so widened as to permit the bone-b'ack to fall from
the filtering-chamber, through the grate into the receiving chamber.
It will be understood that this capacity of operation is common to many systems
of grate-bars of different forms in cross-section. Thus, it will be possessed by flat
slats arranged in relation to each other like the slats of a venetian blind, so that
one edge of each slat overlaps the edge of the slat adjoining it on one side, and its
other edge underlaps the edge of the slat adjoining it on the other side.
As the entire weight of the column of bone-black contained in the filtering
chamber rests upon the grate, it will be obvious that considerable power would be
required to rock such slats from their more nearly horizontal positions toward
their more nearly vertical positions.
It is a specific feature of the present improvements that the grate bars are so
shaped in cross section that in rocking them in either direction they do not exert
any lifting effect upon the superincumbent bone. black, and they are therefore more
easily rocked.
As will be seen on reference to the drawings, the uppermost surface of each
grate-bar is formed into the convex surface 1 which is concentric with the axis
upon which the grate-bar oscillates. The opposite edges of the convex surface 1
form acute angles with the sides 2 and 3 respectively. The sides 2 and 3 extend
radially a short distance toward the axis of the grate-bar and then curve outwardly,
and terminate upon the surface of the cylindrical portion 4 of the grate-bar.
The grate-bars are so proportioned and the distances between their axes so
arranged, that when either bar has completed its rocking movement in one
direction, as shewn in Figure 7, the flat portion of its side 2 occupies a vertical
position in the plane of its axis, and the acute angle formed by the junction of its
side 3 with the edge of the convex surface I is brought to rest so near the con-
centric surface of the cylinder 4 of the grate-bar next adjoining it, as to prevent
the hone-black from falling through between the bars.
When either grate-bar has, as illustrated in Figure 1 completed its rocking
movement in the opposite direction, the flat portion of its side 3 is brought into a
vertical position in the plane of its axis, and the acute angle formed by the union
of its side 3 with the edge of its convex surface 1 is brought near enough to the
surface of the cylinder 4 of the grate-bar next adjoining it on the opposite side to
prevent the bone-black from falling through between the bars.
It results from the proportions and range of oscillatory motion of the grate-bars
that in swinging in either direction they successively uncover all portions of the
bottons of the column of superincumbent bone-black, and thus open a path for the
discharge of the entire lower stratum of the column.
When the dimensions of the filtering chamber require it, the grate-bars are
provided respectively with intermediate supports in semi-circular grooves formed
transversely in the tops of the intermediate horizontal girders K, K, K which are
supported at their opposite ends respectively, upon brackets K¹ K¹ bolted to the
walls of the receiving chamber. The intermediate girders K K K are rounded or
bevelled at the top, in order that there may be no lodgment upon them of the
bone-black which falls from the filtering-chamber.
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
ne by my foreign correspondent, I declare that what I claim is
First. In a continuous filter for purifying sugar-liquor by the process of upward
Gltration through bone-black, the combination, as herein set forth, of the filtering
chamber A, provided at the bottom with a series of horizontal rocking grate-bas
mounted in bearings formed in a stationary frame, or in stationary girders; means
for rocking the said grate-bars upon their longitudinal axes; a receiving chamber,
beneath the filtering chamber means for removing the exhausted bone-black from
the receiving chamber; and means for introducing into the receiving chamber the
sugar-liquor, which is to be purified, under sufficient head to enable it to make its

page_text: way upward through the column of bone-black contained in the filtering chamber
to the level of the outlets through which it is discharged from the filtering
chamber.
Second. The combination of the filtering chamber A, and the receiving chamber B,
with the grate composed of the horizontal rocking grate-bars F, F the upper edges
of each of which grate-bars is, at the conclusion of the rocking motion of the bar in
one direction, carried against the grate-bar which adjoins it, and at the conclusion
of the racking motion in the other direction is brought to rest in the vertical
plane of its axis of oscillation.
Third. The combination, as herein set forth, of the filtering chamber A; the
receiving chamber B; the system of horizontal grate bars F F pivotted in
stationary bearings; one or more connecting rods F2, linked respectively to one or
more horizontal slide-rods, provided with suitable bearings in the side wall of the
receiving chamber; and means for applying power to the said slide-rods for the
purpose of imparting a rocking motion to the grate-bars.
Fourth. The combination of the filtering-chamber A, and the receiving chamber B,
with the system of horizontal rocking grate-bars F, F journalled at their ends in
stationary bearings, and also supported in one or more half bearings formed in one
or more intermediate girders K, K as, and for the purpose, set forth.
Fifth. The intermediate transversely-grooved horizontal girders K, K rounded
or bevelled at the top, in combination with the system of rocking grate-bars F, F,
the filtering chamber A, and the receiving chamber B.