Improvements in Filter Presses and similar Filtering Apparatus
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Filter Presses and similar Filtering Apparatus.
•
I, JOHN WILLIAMSON, of 65, West Regent Street, Glasgow, in the County of
Lanark, Chemical Engineer, do hereby declare the nature of this invention to be
as follows:-
-
This invention which relates to filter presses and similar filtering apparatus
consists in making provision for shifting the position of the frames of the press
or of the projections or gratings in the frames in relation to the filter cloth or
other filtering medium resting thereon or of the cloth in relation to stationary
frames in order that fresh filtering areas may be presented for the passage of the
liquid to be filtered and that the life of the filtering medium may be lengthened.
The invention is especially applicable in connection with filtering apparatus in
which practically continuous filtration is obtained by periodical brushing of the
exposed surfaces of the filtering medium but it may also be advantageously applied
in ordinary filter presses.
In carrying out the invention the plates of the press when of circular or disc-
like form are adapted to rotate or oscillate to a greater or less extent on or with
the central shaft on which they are secured; and for that purpose the rim or a
portion of the rim of each plate has a number of teeth formed on it or is fitted
with a circular toothed rack to gear with a toothed pinion supported between
each pair of plates and whose spindle extends outwards through the filter casing
and is there fitted with an actuating wheel, lever, crank or like means. By this
arrangement two adjoining plates are adapted to be turned in opposite directions;
and the several plates of the filter press may be simultaneously actuated by con-
necting the spindles of the toothed pinions by gearing. Or the periphery of each
plate may be toothed and the whole actuated in the same direction by means of
a long toothed pinion engaging the teeth on the several plates.
When the plates are of rectangular form reciprocating motion is imparted to
them to change the relative positions of the gratings and the filtering medium by
means of toothed pinions engaging teeth or toothed projections on the plates the
alternate plates being shifted in opposite directions by placing the pinions be-
tween adjoining pairs of plates; or the plates being all shifted in the same direc
fion by a pinion or pinions engaging teeth on the edges of the plates, or by a rod
passing through the edges of the filter casing and attached to the plate or plates
being pushed in or out by suitable gearing.

page_text: Improvements in Filter Presses and similar Filtering Apparatus.
I, JOHN WILLIAMSON, of 65, West Regent Street, Glasgow, in the County of
Lanark, Chemical 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 which relates to filter presses and similar filtering apparatus
consists in making provision for shifting the position of the frames of the press
or of the projections or gratings in the frames in relation to the filter cloth or
other filtering medium resting thereon or of the cloth in relation to stationary
frames in order that fresh filtering areas may be presented for the passage of the
liquid to be filtered and that the life of the filtering medium may be lengthened.
The invention is especially applicable in connection with filtering apparatus in
which practically continuous filtration is obtained by periodical brushing of the
exposed surfaces of the filtering medium but it may also be advantageously applied
in ordinary filter presses.
In carrying out the invention the plates of the press when of circular or disc-
like form are adapted to rotate or oscillate to a greater or less extent on or with
the central shaft on which they are secured; and for that purpose the rim or a
portion of the rim of each plate has a number of teeth formed on it or is fitted
with a circular toothed rack to gear with a toothed pinion supported between
each pair of plates and whose spindle extends outwards through the filter casing
and is there fitted with an actuating wheel, lever, crank or like means. By this
arrangement two adjoining plates are adapted to be turned in opposite directions;
and the several plates of the filter press may be simultaneously actuated by con-
necting the spindles of the toothed pinions by gearing. Or the periphery of each
plate may be toothed and the whole actuated in the same direction by means of
a long toothed pinion engaging the teeth on the several plates.
When the plates are of rectangular form reciprocating motion is imparted to
them to change the relative positions of the gratings and the filtering medium by
means of toothed pinions engaging teeth or toothed projections on the plates the
alternate plates being shifted in opposite directions by placing the pinions be-
tween adjoining pairs of plates; or the plates being all shifted in the same direc-
tion by a pinion or pinions engaging teeth on the edges of the plates, or by a rod
passing through the edges of the filter casing and attached to the plate or plates
being pushed in or out by suitable gearing.
The invention is illustrated by the accompanying drawings, Fig. 1 being a ver-
tical section through one of the filter plates, and Fig. 2 a transverse vertical
section through the filter casing. Figure 3 is a view showing one method of
rotating the filter gratings and Figures 4 and 5 are respectively plan and vertical
section of a detail of the filter showing another method of revolving the gratings.
Figure 6 is a plan of part of a rectangular grating, and Figure 7 a horizontal
section on the line x-x, Fig. 6, showing the position of the teeth on the gratings
and of the actuating spur wheel, whilst Fig. 8 is a modified arrangement of the
actuating mechanism. Figs. 9 and 10 are respectively part elevation and hori-
zontal section to different scales of a method of shifting the rectangular gratings
by means of pull or push rods actuated by suitable mechanism and Fig. 11 shows
a method of oscillating the circular gratings by a similar arrangement of rods.
When the plates of the filter are circular or disc-like in form, as shown at a in
Figs. 1 and 2, the gratings 6 are likewise circular in form and revolve round the
centre projections c, which are encircled by rings of incorrodible metal d. The
design of the grating, as regards the arrangement of the ribs, can advantageously

page_text: be of the forms shown in any of the four views in Fig. 2, the aim of the design
being to change the points of contact between the grating and the filtering medium
as much as possible on the position of the grating being slightly changed. The
ribs are also narrowed on the outside, where the filtering medium rests.
In order to revolve or oscillate these gratings the rim or a portion of the rim
of each grating has a number of teeth formed on it or is fitted with a circular
toothed rack e, as shown in Fig. 4. Into this rack gears a toothed pinion f, sup-
ported between each pair of gratings. This pinion is firmly attached to the edge
of the plate as illustrated in Fig. 5, the spindle f¹ being provided on its outer end
with means of rotation. By this arrangement two adjoining plates are adapted
to be rotated or oscillated in opposite directions and if it is desired to actuate all
the pinions in a filter simultaneously, the spindles are connected by suitable
gearing, either toothed wheels of convenient pitch or to chain wheels and a chain,
the power being applied at the end of the machine if so desired. The motions
of these wheels depend however on the extent to which the rims of the gratings
are provided with teeth.
An alternative method of revolving or oscillating the gratings is illustrated in
Fig 3. As there shown the periphery of the grating is provided with teeth g
and the whole of the gratings are then actuated in the same direction by the
pinion h. This pinion extends the length of the filter and is supported in the
end plates or standards by suitable bearings and stuffing glands. If the periphery
of the grating is only partially toothed, the gratings are then merely oscillated,
but either movement is equally effective in attaining the desired object.
A further modification of the mechanism for oscillating the circular gratings
to shift their positions relatively to the filter cloths is illustrated by Fig. 11 and
consists of a rod carried through a stuffing box in the side of the filter casing to
engage a rod which preferably ties together all the gratings, the rod being pulled
out or pushed in to oscillate all the gratings in the same direction.
When the plates are of rectangular form, the relative positions of the gratings
and the filtering medium are altered by imparting a reciprocating motion to the
gratings. As shown in Figs. 6 and 7 a number of teeth or toothed projections
are provided at the bottom of the gratings on the back thereof as at i, and into
these teeth or toothed projections gears a small pinion k, situated one between
each grating. This pinion is connected to a spindle and otherwise attached to
the edge of the plate in the same manner as herein before described and illustrated
in Fig. 5. The rotation of the pinion imparts a reverse motion to the two gratings
and if it is desired to shift all the gratings of a filter simultaneously the method
herein before described becomes similarly applicable.
Instead of forming teeth on the back of the grating; teeth may be formed on
the bottom edge as illustrated at 7 in Fig. 8. In this arrangement the actuating
pinion m extends the whole length of the filter, thereby engaging every grating
contained therein, and being suitably supported at both ends by bearings and
stuffing glands.
Figs. 9 and 10 illustrate another method of shifting the position of the gratings.
A rod n passes through the side of the plate a¹ and by means of the notched
block n' attached thereto grips the nearest bar of the grating. The outer end
of the rod after passing through the gland and stuffing box n³ terminates in a
slotted collar n'. These collars n' are then actuated by the bar n³ which passes
through them and to which is imparted a reciprocating motion by means of suitable
mechanism at both ends of the machine.
The design of grating most suitable for a rectangular shaped filter assumes
the form shown in Figure 6, for reasons herein before explained.
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:
In a filter press the provision of means for periodically changing the position

page_text: of the filter gratings or frames relatively to the filter cloths or other filtering
media resting on them substantially as and for the purpose set forth.
Dated this 10th day of February 1898.
WALLACE FAIRWEATHER,
Of the Firm of Cruikshank & Fairweather,
Chartered Patent Agents, 62, Saint Vincent Street, Glasgow,
Agent for the Applicant.