Year: 1884

page_text: I WALTER OLDHAM of 10 Devonshire Road, Balham, Surrey, Engineer seek leave
to amend the specification and drawings of Letters Patent No 7831 of 1884, as
shown in red ink in the copy of the original specification hereunto annexed.
My reasons for making this amendment are as follows: namely that since filing
my Complete Specification I have discovered that some parts included in my
claims were not so novel as I at the time supposed.
In the matter of the application made by Walter Oldham for leave to amend the
Specification of Letters Patent N° 7831 of 1884.
I hereby grant leave to the said Walter Oldham to amend the said Specification
in the manner proposed.

page_text: I WALTER OLDHAM of No 10 Devonshire Road Balham in the County of Surrey
Engineer do hereby declare the nature of my Invention for "IMPROVEMENTS IN
FILTERS" to be as follows:-
The object of my Invention is the construction of filters in such manner that
they may continue in efficient action for a great length of time without its being
necessary to disturb the bed of filtering material.
My improved filter consists of a case, by preference cylindrical, and by preference
also arranged in a vertical position. This case is closed at the upper end by a
cover, and it is capable of sustaining a considerable pressure. Within the case and
supported on the bottom thereof thero is an inner cylinder the sides of which are
formed of perforated metal plate covered with very fine wire gauze, or it may be
other very fine reticulate material, but by preference I use very fine gauze to which
a smooth surface has been imparted by passing it between rollers, and it also may
with advantage for many purposes be protected by electro plating with nickel.
Within this cylinder again there is a third perforated cylinder of comparatively
small diameter also covered with fine gauze and of a length somewhat less than that
of the intermediate exterior cylinder. It is closed at the upper end and at the
lower end is connected with a reservoir chamber to which a cock is attached or
with a pipe passing out at the bottom of the apparatus and terminating at the
exterior in a cock which is used for drawing off the filtered liquor.
The water or other fluid to be filtered is admitted under considerable pressure by
a pipe connected centrally with the cover of the apparatus.
The current of liquid as it enters is deflected by the cover of the larger
perforated cylinder which is immediately below the entrance. This cover is by
preference not perforated, and it directs the current of liquid into the comparatively
narrow space which is left between the outer cylinder and the metallic gauze which
forms the sides or walls of the intermediate cylinder.
The liquid passes through the gauze leaving any grosser impurities on the exterior
and it percolates through the granular carbonaceous matter or other filtering
material with which the interior of the outer gauze cylinder is closely packed with
the exception of the space occupied in the centre thereof by the small inner
perforated cylinder previously mentioned.
The liquid in finding its way amongst the filtering material is thoroughly cleansed
of all solid impurities; it reaches the interior of the inner perforated cylinder, and
is drawn off as filtered liquor by the cock connected with this cylinder at its
lower end.
The grosser impurities which are strained out by the gauze forming the sides of
the intermediate cylinder will for the most part detach themselves, and fall to the
bottom of the apparatus, and here another cock is provided upon the side of the
outer casing, by which unfiltered liquor can be drawn off from time to time, and
this will carry out with it the solid matter which is thus deposited in the lower
part of the space between the casing and the gauze surface within.
From the nature of the fine gauze surface employed, and the smoothness of the
surface imparted to it by lamination, and the favorable position in which it is
placed in this filter the greater part of the impurities which it retains will fall
away in the manner described, and it will be long before the surface becomes so far
choked as to prevent further efficient filtration; when this occurs I cleanse the
surfaces by adinitting steam or air or cleansing fluid under pressure by the cock
by which, when the apparatus is in use, the filtered liquid is drawn off.

page_text: This steam air or cleansing fluid forces its way through the filtering material,
and through the gauze sides within which this bed is contained, and clears the
surface from obstruction. The cleansing may be aided by means of an angular
brush drawn to and fro along the cylindrical surface. This cylindrical brush may
be carried by rods passing out through the cover of the apparatus by stuffing boxes.
In some cases in place of fixing the inner cover which keeps the filtering bed in
place, I form this cover as a piston and it may have a rod attached, passing out also
by a stuffing box on the cover of the apparatus, in which case the entrance pipe for
the liquid is placed away from centre of cover.
This piston like cover is connected with a lever or other like apparatus, by
which it may be moved a short distance so as to keep it constantly in contact with
the bed of filtering material, and cause it to follow any settlement which may take
place therein; and it also allows of the bed being released to some extent during
the operation of cleansing by steam or air, and afterwards being again compacted,
and this without opening the case. of the filter.
When it is required to increase by heat the fluidity of the liquid-heated steam
or hot air may be introduced by a separate cock attached to the outer cylinder or a
jacket round the outer cylinder may be provided.
This system may be applied as a low pressure filter with or without the top
cover.
The inner cylinder containing the filtering material may be made with separate
base from the outer cylinder so as to be removeable and when of great length may
be in two or more sections to facilitate the discharging of the exhausted filtering
material and the repairing of damage to the wire gauze.
Or the inner cylinder may be open at the lower end and fit into a ring or
socket at bottom of outer cylinder in centre of which socket the narrow innermost
cylinder is attached. Thus when the intermediate cylinder is drawn up the
filtering material will fall out of it.
In some cases it is convenient to arrange two or more filtering cylinders within
the same casing.

page_text: "
I WALTER OLDHAM of N° 10 Devonshire Road Balham in the County of Surrey
Engineer do hereby declare the nature of my invention for IMPROVEMENTS IN
FILTERS" and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
The object of my Invention is the construction of filters in such manner that
they may present a very large filtering surface in a cheap and compact form of
construction and may continue in efficient action for a great length of time without
its being necessary to disturb the bed of filtering material.
My improved filter consists of a vertical case by preference cylindrical. This
ense is closed at the upper end by a cover-and it is capable of sustaining a con
siderable-pressure-or-the ease-may-be-open-at-the-top-and-the filter worked without
the pressure-of-a head of water above it. Within the ease and-supported on the
bottom-thereof-there--is--an-inner-cylinder the sides of which are formed of
perforated metal plates by preference covered with fine wire gauze or it may be
other fine reticulate material. In some cases I use very fine gauze to which a
smooth surface has been imparted by passing it between rollers and it also may
with advantage for many purposes be protected by electro plating with nickel.
Within this cylinder again there is a third perforated cylinder of comparatively
small diameter also covered with fine gauze and of a-length somewhat less than
that-of-the-intermediate-exterior cylinder. It is closed at the upper-end-and-at
the-lower-end-is-connected-with-a
h-a-reservoir-chamber-to-which-a-cock-is-attached-or
with a pipe passing out at the bottom of the apparatus and terminating at the
exterior-in-a-cock-which-is-used-for-drawing-off the filtered-liquor.
The space between the two perforated cylinders is filled with filtering material.
The water or other fluid to be filtered is-admitted-into-the-comparatively-narrow
space which is left between the outer-eylinder and the metallio gauze-which-forms
the-sides-or-walls-of-the-intermediate-eylinder.
The liquid passes through the gauze leaving any grosser impurities on the
exterior and it percolates through the granular carbonaceous matter or other
filtering material with which the interior of the outer gauze cylinder is closely
packed with the exception of the space occupied in the centre thereof by the small
inner perforated cylinder previously mentioned.
The liquid in finding its-way--amongst--the-filtering material is thoroughly
eleansed-of-all-solid impurities;--it--reaches the interior of the inner perforated
cylinder and is--drawn off as filtered liquor by the cock connected with this
eylinder-at-its-lower-end.
The grosser-impurities which-are-strained out by the gauze-forming the sides of
the intermediate cylinder will for the most part detach-themselves, and fall to the
bottom of the apparatus, and here another cock-is-provided-upon the side of the
outer-ensing by which unfiltered liquor can be drawn-off from-time to time and
this will carry out with it the-solid matter which is thus deposited in the lower
purt-of-the-space between the easing-and-the-gause-surface within.
From the nature of the fine gauze surface employed and the favorable position in
which-it-is-placed in this filter the greater part-of-the-impurities which it retaine
will fall away in the manner described and it will be long before the surface
becomes-so-far-eboked-as-to-prevent further efficient-filtration-;-when-this-occurs f
eleanse the surfaces by admitting water or steam or air or cleansing-fluid to the
interior of the inner cylinder-;-it-forces-its way through the filtering material and
through the gauze sides within which this bed is contained and eleurs the surface
from--obstruction. The cleansing may be aided by means of an annular brush
drawn to and fro along the cylindrical surface. This-cylindrical brush-may-in-the

page_text: wire-gauze.--But if covered with gauze-the-gauze should be merely fine enough to
prevent the filtering material from escaping when the reverse cleansing action is
employed.
The space between the cylinders d and e is filled with any suitable filtering
material in a granular fibrous or cellular form, sawdust either carbonised or
otherwise I commonly employ but animal charcoal, sponges, wool, bran, sand, ashes
or other divided filtering material may in some cases be used with advantage it
being understood that I in no way limit myself to the description of filtering.
material employed. For instance there are certain liquids which require a special
filtering material on account of flavor or for other valid reason.
When employing sawdust or like material I mix it with water until it is semi-
fluid and in this state pour it into the space it is intended to occupy and allow it
to settle itself into a compact mass by drainage.
f-is-a-piston-like-cover which rests-on-the-top-of-the filtering material between
the-cylinders-d-and-e-and-serves to keep it in n-compact-state-and-to-compress and
release-it-when-necessary. The cover-f-is-earried-by-a-serew-g-passing-through-the
eentre of the cross bar c-and-by-turning the serew the cover can be raised-or
lowered. In the ease-of-a-closed-filter a rod-passing through-a-stuffing box takes
the-place--of--the--serew--and--it-is pressed-down-by--a-lever--and--weight--this
arrangement of lever and weight may also be applied-to-the-filters-without-elesed
eover-a³-is-an-aperture by which-the-water-or-liquid-to-be-filtered-is-admitted-
this--aperture--may-be--connected--with--a--pipe-running-round-the--interior--of
easing-a.-a.-and-piereed with small-holes-so-as-to-break-the first shook-of the-liquid
entering-the-filter. This coil of perforated piping may also serve to cleanse the
perforated easing-d.-d.-during-which operation-the-aperture-63-may-be closed and
a-opened. Or-the-shock of entrance of liquid may be broken by some-other
convenient-adjustment: a stop cock should be provided in connection with it to
regulate the flow. -a' is another aperture at the lower part of the ease or cylinder a
by which deposit may be drawn off from time to time; it also is provided with
a-stop-cock.-63³-is-an-opening-in the centre of the bottom-b-by-which-the-filtered
liquid-is-drawn-off-it-flows-either into-a-eistern or directly to the point where it is
required for use. The cock on the pipe leading from the opening-b
-6³-serves to
adjust-the-speed-of filtering. If at any time the liquid should appear-imperfectly
filtered this cook should be partly closed to check the flow until only so much
liquid-can-pass-as the filter is able to deliver-in-a-pure-and bright condition.-b-is
an-opening-in-the-bottom-b-to which a cover-bx is fitted, this is removed when it
is desired--to--withdraw the filtering material-and-replace-it with fresh as will
become-necessary-after-the filter has been long-in-use.--But-for-a-considerable time
the-filtering-material-may be kept sufficiently-pure-and-open by from-time-to-time
reversing the direction of the flow through it. In order to cleanse the filter in
this manner-1-provide a pipe-with-a-stop-cock-connecting the inlet pipe-at-a³ with
the outlet-at-63. The cleansing operation--is-conducted-us-follows, the filtering is
stopped by closing-the-inlet-and-outlet-cocks-and-the-space-between the cylinders-d
and-e-is-emptied by opening the outlet-at-a'. Then-by-the-pipe-specially provided
for the purpose-water or other-fluid is admitted-at-b3-and-this-water-then-filtering
from-within-outwards-carries-out with it much of the impurity-which-the-filtering
material had previously--separated-from-the-water--and it passes away by the
outlet a'. The cleansing may-in some cases be facilitated by slightly lifting the
piston or cover c to relieve the filtering material from pressure. But in many
eases-it will be necessary to compress the filtering material by this piston to prevent
the cleansing fluid from making or finding out fissures through which it might
esenpe-without-passing-through-and-cleansing the entire mass of filtering material.
A-more-complete-eleansing may be effected by the use of steam-or-compressed-air
in-eases where-this is convenient.
Sometimes in place of the ease or cylinder-a-being arranged as described I provide
a cistern to receive (it-may-be) several filtering apparatus. In this case I may
have sockets in the bottom of the cistern into which cone plugs upon the bottoms b

page_text: of the filters fit. The outlets 63 in this arrangement are through the plugs so as to
be able to lift out an exhausted filtering cylinder and drop a fresh one into its
place. Or several of these filtering oylinders may be fixed in a cistern-in-a-similar
manner to the way the single cylinder is placed-in-easing a. a. in the Drawing or
in-any-other-way that may be found most convenient and practical for working.
For instance each cylinder (or several cylinders) can be isolated from the remainder
in the same cistern so as to admit of part being cleansed while the remainder are
at work.
The-arrangements above described ean in view of economy of construction-be
simplified in the following manner: The relations of the three casings-a.-d.-e.
remaining the same the moveable piston-f-and-its-rod-g-may be suppressed and the
interior-perforated tube-e-may be prolonged up-to-the-level-of-the-cylinder d-on
which is fixed-a-plate which guarantees the filtering-material-from-direct-contact
with the liquid-to be filtered entering through-the-cover of the outer easing a.
The inlet-a³-may-be-suppressed-and on-cover of casing-a-may-be-fixed two-inlets
with-tops-which--will designate as X Y-of-which-X-brings-the water-to-be-filtered
through top easing a, and Y-is-prolonged by an-india-rubber-pipe-or-otherwise-into
the--interior--of-tube--e--and introduces the--eleansing fluid when needed. The
two-orifices-a'-und-63-are-supplied-with-taps.-To-filter; X-and-b³-are-opened;-to
eleanse-X-and-b³ are shut and Y and a' are opened. In order to prevent the
passage of non-filtered water through-the-top-of inner tube-e-in-ease of an empty
space--being--produced in top of easing d by the settling down of the-filtering
material, I may limit the perforations of tube e to a convenient distance from the
top-of-the-filtering column.
I-may-also-limit-the-perforations-in-eylinder-d-to a convenient-distance-from-its
bottom-when-i-wish-to-inerease the capacity for the collection-of-deposit-between
eylinders-d-and-a.
Having thus particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that
I claim -
First A The filter constructed and acting consisting-of-two-eases of perforated
metal one-within the other and with granular, fibrous, cellular or finely divided
filtering-material-between-them-the-said-parts-being-contained-in-an-outer-vessel-to
which-the-liquid to be filtered is supplied-and-the-filtered-liquid being-drawn off
from-the-interior-of-the-inner-ease-substantially-as-described.
Second The combination with--a filter such as defined by the first claiming
elause-of-wire-gauze-in-the-manner-described.
Third The-combination-with-a-filter-such-as-defined by the first claiming-clause
of a moveable-cover-compacting the filtering material in the space between the
two-perforated-eases substantially-as-described.
Fourth The combination-with-a-filter such as defined by the first-claiming
clause-of-cleansing apparatus causing water-or-eleansing fluid-to-flow-in-the-reverse
direction through the granular or divided-filtering material-contained-between the.
two-perforated-eases.
Fifth The simplified arrangement substantially as described with reference in
respect to Figure 2-of the annexed Drawings.

page_text: I WALTER OLDHAM of N° 10 Devonshire Road Balham in the County of Surrey
Engineer do hereby declare the nature of my Invention for "IMPROVEMENTS IN
FILTERS to be as follows:-
=
"
The object of my Invention is the construction of filters in such manner that
they may continue in efficient action for a great length of time without its being
necessary to disturb the bed of filtering material.
My improved filter consists of a case, by preference cylindrical, and by preference
also arranged in a vertical position. This case is closed at the upper end by a
cover, and it is capable of sustaining a considerable pressure. Within the case and
supported on the bottom thereof there is an inner cylinder the sides of which are
formed of perforated metal plate covered with very fine wire gauze, or it may be
other very fine reticulate material, but by preference I use very fine gauze to which
a smooth surface has been imparted by passing it between rollers, and it also may
with advantage for many purposes be protected by electro plating with nickel.
Within this cylinder again there is a third perforated cylinder of comparatively
small diameter also covered with fine gauze and of a length somewhat less than that
of the intermediate exterior cylinder. It is closed at the upper end and at the
lower end is connected with a reservoir chamber to which a cock is attached or
with a pipe passing out at the bottom of the apparatus and terminating at the
exterior in a cock which is used for drawing off the filtered liquor.
The water or other fluid to be filtered is admitted under considerable pressure by
a pipe connected centrally with the cover of the apparatus.
The current of liquid as it enters is deflected by the cover of the larger
perforated cylinder which is immediately below the entrance. This cover is by
preference not perforated, and it directs the current of liquid into the comparatively
narrow space which is left between the outer cylinder and the metallic gauze which
forms the sides or walls of the intermediate cylinder.
The liquid passes through the gauze leaving any grosser impurities on the exterior
and it percolates through the granular carbonaceous matter or other filtering
material with which the interior of the outer gauze cylinder is closely packed with
the exception of the space occupied in the centre thereof by the small inner
perforated cylinder previously mentioned.

page_text: The liquid in finding its way amongst the filtering material is thoroughly cleansed
of all solid impurities; it reaches the interior of the inner perforated cylinder, and
is drawn off as filtered liquor by the cock connected with this cylinder at its
lower end.
The grosser impurities which are strained out by the gauze forming the sides of
the intermediate cylinder will for the most part detach themselves, and fall to the
bottom of the apparatus, and here another cock is provided upon the side of the
outer casing, by which unfiltered liquor can be drawn off from time to time, and
this will carry out with it the solid matter which is thus deposited in the lower
part of the space between the casing and the gauze surface within.
From the nature of the fine gauze surface employed, and the smoothness of the
surface imparted to it by lamination, and the favorable position in which it is
placed in this filter the greater part of the impurities which it retains will fall
away in the manner described, and it will be long before the surface becomes so far
choked as to prevent further efficient filtration; when this occurs I cleanse the
surfaces by admitting steam or air or cleansing fluid under pressure by the cock
by which, when the apparatus is in use, the filtered liquid is drawn off.
This steam air or cleansing fluid forces its way through the filtering material,
and through the gauze sides within which this bed is contained, and clears the
surface from obstruction. The cleansing may be aided by means of an angular
brush drawn to and fro along the cylindrical surface. This cylindrical brush may
be carried by rods passing out through the cover of the apparatus by stuffing boxes.
In some cases in place of fixing the inner cover which keeps the filtering bed in
place, I form this cover as a piston and it may have a rod attached, passing out also
by a stuffing box on the cover of the apparatus, in which case the entrance pipe for
the liquid is placed away from centre of cover.
This piston like cover is connected with a lever or other like apparatus, by
which it may be moved a short distance so as to keep it constantly in contact with
the bed of filtering material, and cause it to follow any settlement which may take
place therein; and it also allows of the bed being released to some extent during
the operation of cleansing by steam or air, and afterwards being again compacted,
and this without opening the case of the filter.
When it is required to increase by heat the fluidity of the liquid-heated steam
or hot air may be introduced by a separate cock attached to the outer cylinder or a
jacket round the outer cylinder may be provided.
This system may be applied as a low pressure filter with or without the top
cover.
The inner cylinder containing the filtering material may be made with separate
base from the outer cylinder so as to be removeable and when of great length may
be in two or more sections to facilitate the discharging of the exhausted filtering
material and the repairing of damage to the wire gauze.
Or the inner cylinder may be open at the lower end and fit into a ring or
socket at bottom of outer cylinder in centre of which socket the narrow innermost
cylinder is attached. Thus when the intermediate cylinder is drawn up the
filtering material will fall out of it.
In some cases it is convenient to arrange two or more filtering cylinders within
the same casing.
Dated this 16th dow of Mo 1984
CARPMAEL & Co.,
Agents for the Applicant.

page_text: I WALTER OLDHAM of N° 10 Devonshire Road Balham in the County of Surrey
Engineer do hereby declare the nature of my Invention for "IMPROVEMENTS IN
FILTERS" and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
The object of my Invention is the construction of filters in such manner that
they may present a very large filtering surface in a cheap and compact form of
construction and may continue in efficient action for a great length of time without
its being necessary to disturb the bed of filtering material.
My improved filter consists of a case by preference cylindrical. This case is
closed at the upper end by a cover and it is capable of sustaining a considerable
pressure or the case may be open at the top and the filter worked without the
pressure of a head of water above it. Within the case and supported on the
bottom thereof there is an inner cylinder the sides of which are formed of
perforated metal plates by preference covered with fine wire gauze or it may be
other fine reticulate material. In some cases I use very fine gauze to which a
sinooth surface has been imparted by passing it between rollers and it also may
with advantage for many purposes be protected by electro plating with nickel.
Within this cylinder again there is a third perforated cylinder of comparatively
small diameter also covered with fine gauze and of a length somewhat less than
that of the intermediate exterior cylinder. It is closed at the upper end and at
the lower end is connected with a reservoir chamber to which a cock is attached or
with a pipe passing out at the bottom of the apparatus and terminating at the
exterior in a cock which is used for drawing off the filtered liquor.
The space between the two perforated cylinders is filled with filtering material.
The water or other fluid to be filtered is admitted into the comparatively narrow
space which is left between the outer cylinder and the metallic gauze which forms
the sides or walls of the intermediate cylinder.
The liquid passes through the gauze leaving any grosser impurities on the
exterior and it percolates through the granular carbonaceous matter or other
filtering material with which the interior of the outer gauze cylinder is closely
packed with the exception of the space occupied in the centre thereof by the small
inner perforated cylinder previously mentioned.
The liquid in finding its way amongst the filtering material is thoroughly
cleansed of all solid impurities; it reaches the interior of the inner perforated
cylinder and is drawn off as filtered liquor by the cock connected with this
cylinder at its lower end.
The grosser impurities which are strained out by the gauze forming the sides of
the intermediate cylinder will for the most part detach themselves, and fall to the
bottom of the apparatus, and here another cock is provided upon the side of the
outer casing by which unfiltered liquor can be drawn off from time to time and
this will carry out with it the solid matter which is thus deposited in the lower
part of the space between the casing and the gauze surface within.
From the nature of the fine gauze surface employed and the favorable position in
which it is placed in this filter the greater part of the impurities which it retains
will fall away in the manner described and it will be long before the surface
becomes so far choked as to prevent further efficient filtration; when this occurs I
cleanse the surfaces by admitting water or steam or air or cleansing fluid to the
interior of the inner cylinder; it forces its way through the filtering material and
through the gauze sides within which this bed is contained and clears the surface
from obstruction. The cleansing may be aided by means of an annular brush
drawn to and fro along the cylindrical surface. This cylindrical brush may in the

page_text: case of a closed filter be carried by rods passing out through the cover of the
apparatus by stuffing boxes. The inner cover which keeps the filtering bed in
place I form as a piston and it may have a rod attached passing out also by a
stuffing box on the cover of the apparatus.
This piston like cover is connected with a lever or other like apparatus by which
it may be moved a short distance so as to keep it constantly in contact with the
bed of filtering material and cause it to follow any settlement which may take
place therein; and it also allows of the bed being released or compressed to some
extent during the operation of cleansing by water steam or air and afterwards
being again compacted or released and this without opening the case of the filter.
When it is required to increase by heat the fluidity of the liquid treated, steam
or hot air may be introduced by a separate cock attached to the outer cylinder or a
jacket round the outer cylinder may be provided.
This system may be applied as a low pressure filter with or without the top
cover.
The inner cylinder containing the filtering material may be made with separate
base from the outer cylinder so as to be removeable and when of great length may
be in two or more sections to facilitate the discharging of the exhausted filtering
material and the repairing of damage to the wire gauze.
Or the inner cylinder may be open at the lower end and fit into a ring or
socket at bottom of outer cylinder in centre of which socket the narrow innermost
cylinder is attached. Thus when the intermediate cylinder is drawn up the filtering
material will fall out of it.
In some cases it is convenient to arrange two or more filtering cylinders within
the same casing.
In order that my said Invention may be most fully understood and readily
carried into effect I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
The Drawing Figure 1 represents a filter constructed in accordance with my
Invention.
Figure 2 shows a modification.
In Figure 1 a. a. is the outer case or cylinder of sheet metal and a¹ is an angle
iron ring with which it is strengthened around its upper edge. b is a casting
forming the bottom of the case or cylinder a. The case or cylinder a may either
be closed at the top if it be desired to employ pressure to force the liquid through
the filter or open if it be intended to work the filter without any head above the
top of the case or cylinder. c represents a cover if a cover be employed or a cross
bar if the filter be open at the top. In either case the part c is attached to the
ring a by screws a³ in a way which admits of its being readily detached when
required. d is a perforated cylinder of galvanised iron or other metal it is
stiffened at the top by the ring d¹ fixed around it and at its lower end by the
ring d³ within it. This cylinder I usually clothe externally with fine wire gauze
which is lapped around it and closed up one side by a soldered joint. The
cylinder & drops into a socket b¹ formed to receive it in the cast bottom b. Within
the cylinder d is the smaller cylinder e also of perforated sheet metal and covered
with wire gauze, it has a conical upper end which is unperforated and at its lower
end it fits over the annular projection 62 on the bottom b. This cylinder also may
be covered with wire gauze or the perforations in it may be sufficiently fine to
retain the filtering material without such aid. I would here remark that I do not
always cover the outer cylinder d with fine wire gauze, it is useful so to do only
when the water or liquid contains a notable quantity of gross impurity such as fine
gauze is capable of arresting-this however is frequently the case with water which
has to be filtered. When wire gauze is used a brush to cleanse it may also be
provided as already described.
In cases where it is found advisable to allow all the impurities to collect amongst
the filtering material the perforated cylinders are not required to be covered with

page_text: wire gauze. But if covered with gauze the gauze should be merely fine enough to
prevent the filtering material from escaping when the reverse cleansing action is
employed.
The space between the cylinders d and e is filled with any suitable filtering
material in a granular fibrous or cellular form, sawdust either carbonised or
otherwise I commonly employ but animal charcoal, sponges, wool, bran, sand, ashes
or other divided filtering material may in some cases be used with advantage it
being understood that I in no way limit myself to the description of filtering
material employed. For instance there are certain liquids which require a special
filtering material on account of flavor or for other valid reason.
When employing sawdust or like material I mix it with water until it is semi-
fluid and in this state pour it into the space it is intended to occupy and allow it
to settle itself into a compact mass by drainage.
f is a piston like cover which rests on the top of the filtering material between
the cylinders & and e and serves to keep it in a compact state and to compress and
release it when necessary. The cover fis carried by a screw passing through the
centre of the cross bar o and by turning the screw the cover can be raised or
lowered. In the case of a closed filter a rod passing throug: a stuffing box takes
the place of the screw and it is pressed down by a lever and weight-this
arrangement of lever and weight may also be applied to the filters without closed
cover. a³ is an aperture by which the water or liquid to be filtered is admitted-
this aperture may be connected with a pipe running round the interior of
casing a. a. and pierced with small holes so as to break the first shock of the liquid.
entering the filter.
This coil of perforated piping may also serve to cleanse the
perforated casing d. d. during which operation the aperture 6³ may be closed and
a opened. Or the shock of entrance of liquid may be broken by some other
convenient adjustment: a stop cock should be provided in connection with it to
regulate the flow. a' is another aperture at the lower part of the case or cylinder a
by which deposit may be drawn off from time to time; it also is provided with
a stop cock. 63 is an opening in the centre of the bottom b by which the filtered
liquid is drawn off it flows either into a cistern or directly to the point where it is
required for use. The cock on the pipe leading from the opening b³ serves to
adjust the speed of filtering. If at any time the liquid should appear imperfectly
filtered this cock should be partly closed to check the flow until only so much
liquid can pass as the filter is able to deliver in a pure and bright condition. b' is
an opening in the bottom 6 to which a cover b** is fitted, this is removed when it
is desired to withdraw the filtering material and replace it with fresh as will
become necessary after the filter has been long in use. But for a considerable time
the filtering material may be kept sufficiently pure and open by from time to time
reversing the direction of the flow through it. In order to cleanse the filter in
this manner I provide a pipe with a stop cock connecting the inlet pipe at a³ with
the outlet at b. The cleansing operation is conducted as follows, the filtering is
stopped by closing the inlet and outlet cocks and the space between the cylinders d'
and e is emptied by opening the outlet at at. Then by the pipe specially provided
for the purpose water or other fluid is admitted at 63 and this water then filtering
from within outwards carries out with it much of the impurity which the filtering
material had previously separated from the water and it passes away by the
outlet a. The cleansing may in some cases be facilitated by slightly lifting the
piston or cover c to relieve the filtering material from pressure. But in many
cases it will be necessary to compress the filtering material by this piston to prevent
the cleansing fluid from making or finding out fissures through which it might
escape without passing through and cleansing the entire mass of filtering material.
A more complete cleansing may be effected by the use of steam or compressed air
in cases where this is convenient.
Sometimes in place of the case or cylinder a being arranged as described I provide
a cistern to receive (it may be) several filtering apparatus. In this case I may
have sockets in the bottom of the cistern into which cone plugs upon the bottoms b

page_text: of the filters fit. The outlets b³ in this arrangement are through the plugs so as to
be able to lift out an exhausted filtering cylinder and drop a fresh one into its
place. Or several of these filtering cylinders may be fixed in a cistern in a similar
manner to the way the single cylinder is placed in casing a. a. in the Drawing-or
in any other way that may be found most convenient and practical for working.
For instance each cylinder (or several cylinders) can be isolated from the remainder
in the same cistern so as to admit of part being cleansed while the remainder are
at work.
The arrangements above described can in view of economy of construction_be
simplified in the following manner :-The relations of the three casings a. d. e.
remaining the same the moveable piston f and its rod g may be suppressed and the
interior perforated tube e may be prolonged up to the level of the cylinder d on
which is fixed a plate which guarantees the filtering material from direct contact
with the liquid to be filtered entering through the cover of the outer casing a.
The inlet a³ may be suppressed and on cover of casing a may be fixed two inlets
with taps which I will designate as X Y of which X brings the water to be filtered
through top casing a, and Y is prolonged by an india rubber pipe or otherwise into
the interior of tube e and introduces the cleansing fluid when needed. The
two orifices a¹ and 6s are supplied with taps. To filter; X and 63 are opened; to
cleanse X and b³ are shut and Y and a are opened. In order to prevent the
passage of non-filtered water through the top of inner tube e in case of an empty
space being produced in top of casing d by the settling down of the filtering
material, I may limit the perforations of tube e to a convenient distance from the
top of the filtering column.
I may also limit the perforations in cylinder d to a convenient distance from its
bottom when I wish to increase the capacity for the collection of deposit between
cylinders d and a.
Having thus particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that
I claim -
First A filter consisting of two cases of perforated metal one within the other
and with granular, fibrous, cellular or tinely divided filtering material between
them the said parts being contained in an outer vessel to which the liquid to be
filtered is supplied and the filtered liquid being drawn off from the interior of the
inner case substantially as described.
Second-The combination with a filter such as defined by the first claiming
clause of wire gauze in the manner described.
Third-The combination with a filter such as defined by the first claiming clause
of a moveable cover compacting the filtering material in the space between the
two perforated cases substantially as described.
Fourth-The combination with a filter such as defined by the first claiming
clause of cleansing apparatus causing water or cleansing fluid to flow in the reverse
direction through the granular or divided filtering material contained between the
two perforated cases.
Fifth-The simplified arrangement substantially as described in respect to
Figure 2 of the annexed Drawings.