Improvements in Filters.
Year: 1897

page_text: Date of Application, 16th July, 1897-Accepted, 21st Aug., 1897
COMPLETE SPECIFICATION.
Improvements in Filters.
We, PHILIP ELIOT HODGKIN, of Childwall, Church Road, Richmond, in the County
of Surrey, Engineer, and THE PULSOMETER ENGINEERING COMPANY, LIMITED of
9 Elms Iron Works, Hayle Foundry Wharf, in the same County, Engineers 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 object to enable the screens used in filters for preventing
the escape of the filtering material during the washing or cleaning thereof by.. a
current or currents of water, or water and air or other elastic fluid, to be easily
and quickly removed from the filter for cleaning or other purpose and afterwards
replaced.
For this purpose the screen, the casing of the filter, or a vessel connected therewith,
in which the screen is normally located, and the inlet end of the wash-out pipe or
passage are so constructed and arranged that the screen can be readily drawn away
from the inlet end of the wash out pipe or passage and removed from the filter,.or
the vessel attached thereto, for cleaning or other purpose, and can afterward be
replaced and caused to make a sufficiently good joint with the said inlet end of the
wash out pipe or passage without the use of bolts or other equivalent fastening
devices as I shall now proceed to explain by the aid of the accompanying drawings
which show several forms of filters constructed according to my invention.
Fig. 1 is a vertical section, partly in elevation, and Fig. 2 a sectional plan, showing
one construction.
In this example the body or casing 1 of the filter is made of rectangular shape at
one side and of semi-circular shape at the opposite side and is provided internally at
a point above, the mass of filtering material, which is supported upon a perforated
bottom plate 2, with a horizontal rib or flange 3. In the flat right hand side of the
casing is an opening 4 that extends the full width of the casing and has its lower
side flush with the upper surface of the rib or flange 3. This opening is normally
closed by a door 5. Mounted upon the said rib or flange so as to be capable of
sliding therein in is a screen 6 consisting of a hollow circular casting having perforated
top and botton plates 6º 6b to which are secured by means of radial and circular
bars 6°, sheets 6e of wire gauze or equivalent material that will prevent the escape of
the filtering material when the same is being washed by a current. of water passed
through the filter in the opposite direction to that in which filtering takes place, but
will permit of the escape of the washing water with the impurities contained therein.
The screen casting has a central opening 6 through which, the water to be filtered
can pass downward, and washing water can pass upward to the top of the screen. It
is also provided with a lower annular flange 65 by which it is supported on the rib or
flange 3, and with a lateral conical outlet 6h. In the semi-circular side of 'the
casing 1 opposite the opening.4 is a central opening 7 in which is fixed a branch
pipe 8 that forms part of the wash out pipe and has a conical socket-like end '8"
adapted to receive and fit the conical outlet 6c of the hollow screen and form
therewith a plug and socket joint. To the branch pipe 8 is secured a valve 9 to

page_text: 10 is the
which is attached the remaining portion of the wash out pipe not shown.
inlet for liquid to be filtered; 11 the outlet for filtered liquid; and 12 an opening
with door 13 through which the filtering material can be inserted and the interior of
the filter inspected. With the arrangement described, it will be seen that when the
screen 6 requires cleaning, it can, after removing the door 5, be pulled away from the
socket 8 by means of its handle 14 and withdrawn from the casing 1 through
the opening 4, and after cleaning, can be readily pushed back into place so as to
again form a close joint with the socket 8".
Fig. 3 is a side elevation and Fig. 4 a sectional plan, showing a modified
arrangement in which the hollow screen 6 is made tubular and of are shape as seen
in plan and is connected at one end to a door 4ª that is hinged or jointed to the
casing 1 at 4b, the arrangement being such that after unfastening the door the screen
can be swung by the door in a horizontal direction out of the casing 1 through the
opening 4 therein and after being inspected or cleaned can be swung back so as to
cause the conical end of its outlet 6h to again enter the socket 8* and form a close
joint therewith. The outlet 6h is, in this example, shown as made separate from and
attached by studs and nuts to the inner end of the screen.
Fig. 5 is a vertical section showing another construction of filter according to this
invention. Fig. 6 shows in vertical section and to a larger scale than Fig. 1, the
lower part of the removable screen used therein, and Fig. 7 is a horizontal section
thereof.
In this arrangement, the screen 6 consists of a hollow vertical cylinder formed
with slots surrounded by gauze 6º, and having at its lower end a conical outlet 6h. It
is inserted through the opening 12 in the top of the filter casing 1 its lower conical
outlet 6h fitting into a corresponding vertical socket 8" on the part 8 of the wash-out
pipe which in this case is fixed within the casing 1 opposite the valve 9. The upper
end of the screen may be flanged as shown and arranged to rest upon lugs 15 in the
opening 12.
14 is a handle to facilitate the insertion and removal of the screen.
Fig. 8 is a vertical section showing a filter with a screen mounted in a similar
manner to that shown in Fig. 5 but of modified construction. Fig. 9 shows a portion
of the screen in vertical section and to an enlarged scale, and Fig. 10 is a horizontal
section on the line x x of Fig. 9.
In this case the screen is built up of a number of alternately arranged
castings 6ª, 6 and annular pieces of wire gauze 6e which are clamped between the
castings as shown. Each casting 6A, 6B consists of a central tubular boss connected
by wedge-shaped radial arms to a circular rim. The boss of each casting 6A is slotted
or perforated and made deeper than the corresponding rim, and the rim of each
casting 6B is slotted or perforated and made deeper than the corresponding boss
which is not perforated. The arrangement is such that when the annular pieces of
gauze 6 are clamped between the castings by means of a central bolt 16 they will 4
take the form of a series of flattened truncated cones and present a large screening
area. The washing water in flowing from the filter enters the holes in the rims of
the castings 6B, and passes through the pieces of gauze 6 and the holes in the
bosses of the castings 6 into the vertical column formed by the juxtaposed bosses,
and thence escapes by the conical outlet 6 and wash out pipe 8 as before. By the 4
construction described, the screen can be readily taken to pieces for cleaning or
renewing the pieces of gauze.
Instead of mounting the screen 6 shown in Figs. 5 6 and 7 or in Figs. 8, 9 and 10
within the filter casing 1, it may be mounted within a supplementary vessel 17 fixed
externally to but in communication with the interior of the casing as indicated in 5
dotted lines in Fig. 5, the valve 9 with wash out pipe being attached to the bottom
of the said vessel.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that what we
claim is:
1. A filter wherein the screen for nrawantinum 1
C
5

page_text: washing thereof, the filter casing or a vessel connected therewith in which the screen
is normally located, and the inlet end of the wash out pipe are so constructed and
arranged that the screen can be readily drawn away from the said inlet end of the
wash out pipe and removed from the filter or containing vessel for cleaning or other
purpose and can afterward be replaced and caused to make a close joint with the inlet
end of the wash out pipe without the use of bolts or equivalent fastening devices,
substantially as described.
2. A filter constructed with a hollow washing screen provided with an outlet
adapted to form a plug and socket joint with the inlet end of the wash out pipe or
passage substantially as described.
3. My improved filters with screens and wash out pipes or passages constructed
and arranged substantially as hereinbefore described with reference respectively to
and shown in Figs. 1 and 2; in Figs. 3 and 4; in Figs. 5, 6 and 7; and in
Figs. 8, 9 and 10, of the drawings annexed, or modified as indicated in dotted lines
in Fig. 5.