Improvements in or connected with Filters.
Year: 1892

page_text: Date of Application, 17th June, 1892
Complete Specification Left, 17th Mar., 1893-Accepted, 22nd Apr., 1893
PROVISIONAL SPECIFICATION.
Improvements in or connected with Filters.
I, JAMES GRIEVE LORRAIN, of Norfolk House, Norfolk Street, Strand, in the
County of Middlesex, Consulting Engineer, do hereby declare the nature of this
invention to be as follows:-
:-
My invention has reference to filters and has for its object the oxidation of
matter suspended, immersed or dissolved in the water or other liquid treated.
In carrying my invention into effect I fit the filters with, or adapt to them,
electrodes which may be connected with any suitable source of electrical energy so
that the water or other liquid, or an oxygen compound added thereto, may be
electrolytically decomposed, and the oxygen be liberated so that it may combine with
the oxidisable matter present.
Filters as ordinarily constructed consist of two compartments, one for containing
the water to be filtered as well as the filtering material and the other for containing
the water after it has passed through the filtering material: and in applying my
invention to such forms I may have the electrodes in either or in both of such
compartments. When the arrangement will allow I prefer to place the anode, or
electrode from which the oxygen is given off, at the bottom of the compartment
in which it is immersed so that the liberated oxygen in passing upwards to the
surface of the liquid shall come in contact with as much of the liquid as possible.
When the filtering material is a conductor, as for example in the ordinary forms
of carbon filter, I sometimes constitute it one of the electrodes. When the filtering
material is a block of carbon as in a well known form of filter, and I constitute it
one of the electrodes, I frequently make the other electrode of platinum gauze and
when this gauze is the anode I prefer to have it in the shape of a disc and fasten
it below the carbon block say to an insulating collar on the tube leading from the
centre of the block to the compartment containing the filtered water or on the
tube itself if it be a non-conductor. At other times I make the said other electrode
of platinum wire wound in a helix and placed so as to surround the said block.
The said blocks are usually made hollow, the water passing through from the
exterior to the hollow space. In such a case I may insert both electrodes in the
said space, or when the said carbon block constitutes one of the electrodes. I may
insert the other electrode in the said hollow space as for example by attaching it
in an insulated manner to the tube leading to the compartment for the filtered
liquid.
In cases where the filtering material is not formed of a solid block but consists
of free pieces or particles in a more or less fine state of division I may, if such
filtering material be a nonconductor, place the anode, generally in the form of a
perforated plate or grid or sheet of gauze, below the said filtering material and the
cathode above the said material, the material resting on the anode and the cathode
resting on the material. In such cases the electrodes will preferably take the form
of perforated plates, grids or gauze. If such filtering material be a conductor I
find it convenient to separate the electrodes from the filtering material by non-
conducting perforated or porous septa; and I frequently use such septa even when
the filtering material is a nonconductor. My object in using perforated or porous
septa and perforated or porous electrodes (grids, gauze or the like) is to admit of
downward passage of the liquid and upward passage of the liberated gases. When the
filtering material consists of a coherent substance such for example as cloth or fibrous
material, asbestos fabric, sponge & the like I generally apply the electrodes in the
same way as I do in the cases where the filtering material consists of free or loose pieces

page_text: or particles, except that in such case there is less necessity for a septum to retain the
said material in position. I sometimes employ floating electrodes, say electrodes porous
in such manner as to float or electrodes to which floats or floating materials are
attached. A perforated floating cathode for example is very useful in the compartment
containing the filtered liquid when the anode is placed vertically below it. I find
it convenient to make the internal configuration of the compartments containing
the electrodes such to offer as little resistance as possible to the currents set up in
the liquid by the action of the bubbles of liberated gas; and for this purpose I
sometimes fit the compartments with partitions to guide the flow of such currents
of the liquid. When an electrode employed in my invention is liable to disin-
tegration, as for example when a block of filtering carbon is employed as an anode,
I sometimes encase it in a protecting casing, say of gauze or punctured foil.
When I employ electrodes in the compartment containing the filtered liquid I
generally cause the plate or its equivalent separating the two compartments to be
readily removable so as to admit of ready access to the electrodes. The conducting
wires leading to the electrodes may pass through the body of the filter in any
convenient manner. One convenient way of bringing such wires to the electrodes
in the compartment containing the filtered liquid is through a tube constructed in
the wall of the filter and passing from the top of the filter down to the said
compartment for the filtered water.
My invention may be applied in the case of osmotic and dialytic filters.
Dated this 10th
CT
J. G. LORRAIN.
COMPLETE SPECIFICATION.
Improvements in or connected with Filters.
I, JAMES GRIEVE LORRAIN, of Norfolk House, Norfolk Street, Strand, in the
County of Middlesex, Consulting 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 :-
My invention has reference to filters and has for its object the oxidation of
matters suspended, immersed or dissolved in the water or other liquid treated.
In carrying my invention into effect I fit the filters with, or adapt to them
electrodes which may be connected with any suitable source of electrical energy
so that the water or other liquid, or an oxygen compound added thereto, may be
electrolytically decomposed, and the oxygen be liberated so that it may combine
with the oxidizable matters present.
Filters as ordinarily constructed consist of two compartments, one for containing
the unfiltered water as well as the filtering material (this compartment being itself
sometimes subdivided) and the other for containing the water after it has passed
through the filtering material: and in applying my invention to such forms I may
have the electrodes in either or in both of such compartments. When the arrange-
ment will allow I prefer to place the anode, or electrode from which the oxygen
is given off, at the bottom of the compartment in which it is immersed, so that the
liberated oxygen in passing upwards to the surface of the liquid shall come in
contact with as much of the liquid as possible. When the filtering material is a
conductor, as for example in the ordinary forms of carbon filter, I sometimes con-
stitute it one of the electrodes. When the filtering material is a block of carbon,
as in a well known form of filter, and I constitute it one of the electrodes, I
frequently make the other electrode of platinum gauze and when this gauze is the
anode I prefer to have it in the shape of a disc, and fasten it below the carbon
block, say to an insulating collar on the tube leading from the centre of the block
to the compartment containing the filtered water, or on the tube itself if the said
tube be a non-conductor.
In order that my invention may be more readily understood I have appended.

page_text: hereto sheets of drawings in which similar letters of reference indicate similar or
equivalent parts.
Figure 1 illustrates the case just mentioned in which the block of carbon A
constitutes one of the electrodes, preferably the cathode. B is the anode consisting
of a disc of platinum gauze mounted upon an insulating collar c attached to the
tube C which extends from the centre of the block into the compartment for the
filtered water N. M is the compartment for containing the unfiltered water and
the filtering material.
At other times I make the said other electrode of platinum wire wound in a
helix and placed so as to surround the said block. This case is illustrated in
Figure 2, which differs from the case shown in Figure 1 solely in the fact that the
anode, instead of being a disc of platinum gauze, is a helix of platinum wire
surrounding the filtering block, which is of slightly different shape from that shown
in Figure 1.
The said blocks are usually made hollow, the water passing through from the
exterior to the hollow space. In such a case I may insert both electrodes in the
said space or, when the said carbon block constitutes one of the electrodes, I may
insert the other electrode in the said hollow space, as for example by attaching it
in an insulated manner to the tube leading to the compartment for the filtered
liquid. These two cases are illustrated in Figures 3 and 4 respectively, these
figures differing from one another in the fact that in Figure 3 botli electrodes are
inserted in the hollow space of the carbon block, whilst in Figure 4 only one of
the electrodes, preferably the anode, is so inserted, the block itself in this latter
case constituting the other electrode.
In cases where the filtering material is not formed of a solid block but consists
of free pieces or particles in a more or less fine state of division I prefer, if such
filtering material be a non-conductor, to place the anode below the said filtering
material and the cathode above the said material in such manner that the material
shall rest on the anode and the cathode rest on the material. In such cases the
electrodes will preferably take the form of perforated plates, grids or sheets of
gauze.
If such filtering material be a conductor I find it convenient to separate the
electrodes from the filtering material by non-conducting perforated or porous septa ;
and I frequently use such septa even when the filtering material is a non-conductor.
My object.in using perforated or porous septa and perforated or porous electrodes
(grids, gauze or the like) is to admit of free downward passage of the liquids and
free upward passage of the liberated gases.
These two cases are diagrammatically illustrated in Figures 5 and 6. In
Figure 5, D represents non-conducting filtering material resting upon the anode B,
and upon which rests the perforated cathode. E and F are partitions such as are
usually employed to confine the finely divided filtering material in position, and in
ordinary practice a sheet of asbestos fabric or the like would generally be placed
between the said electrodes and the said partitions.
Figure 6 is a diagram differing from Figure 5 solely in the fact that the filtering
material D is a conductor; and in this case I find it convenient to separate the
electrodes as herein before mentioned by non-conducting perforated or porous septa,
say by the partitions E and F. It is not absolutely necessary that both of the
said electrodes be separated from the conducting filtering material provided one is
so separated but in such case it is the cathode A which should preferably be
separated from the conducting filtering material. The reason of this is that were
the cathode not so separated the filtering material would itself constitute part of
the cathode, and in this case it would very readily polarize owing to the difficulty
which the hydrogen bubbles would have of escaping through the finely divided
conducting material. If therefore the finely divided conducting material is to be
used as an electrode at all, it is preferable to use it as the anode, and to place the
cathode in a position above it. The drawback to using conducting filtering
material, which is usually carbon, as the anode is that in that case it is liable to

page_text: disintegration; but in the case wherein such conducting filtering material is already
finely divided further disintegration does not much matter as in practice the
passage of the fine material into the filtered water is provided against in the
usual way.
When the filtering material consists of a coherent substance such for example as
cloth or fibrous material, asbestos fabric, sponge and the like, I generally apply
the electrodes in the same way as I do in the cases where the filtering material
consists of free or loose pieces particles, of non conducting material except that
in such case there is less necessity for a septum to retain the said material in
position.
or
A
I sometimes employ floating electrodes, say electrodes porous in such manner as
to float, or electrodes to which floats or floating materials are attached.
perforated floating cathode for example is very useful in the compartment
containing the filtered liquid when the anode is placed vertically below it.
This case is illustrated in Figure 7 in which the electrodes A and B are attached
to the annular float G constructed of cork or other light material or of heavier
material of hollow construction. This float G may itself be formed of carbon
sufficiently porous to act as a float and constitute the cathode; and in this case the
conical construction (wedge shaped in cross section with the apex pointing
downwards) prevents the ready adhesion of bubbles of hydrogen on the surface.
In practice I prefer to make the distance between the electrodes adjustable so as
to render them readily adaptable for currents of different electro-motive force.
Figures 8, 9, and 10 illustrate simple devices for readily effecting this
adjustment.
In Figure 8 the arm c¹ is prolonged through the sleeve c² and can be bound in
any position by the binding screw c³. The device shown in Figure 9 differs from
that shown in Figure 8 mainly in the fact that instead of the anode being
supported by a single arm c¹ it is supported by the two arms c c which overlap
one another, one of these arms being provided with a sleeve through which the
other arm passes, and in which the said other arm can be fixed by the binding
screw c³.
Figure 10 differs from Figures 8 and 9 in that instead of employing adjustable
arms I employ a stiffish spiral spring to support the anode. The distance between
the two electrodes is adjusted or regulated by stretching the said spiral spring,
which may be flexible and non-elastic, to a greater or less extent.
In the three latter figures I have shown the distance between the electrodes as
being regulated by the raising or lowering of the anode, but it is of course obvious
that the cathode may be similarly raised or lowered. In practice however it is
generally convenient to fix the cathode in as high a position as possible, say at the
surface of the liquid, and to regulate the distance between the two electrodes by
altering the position of the anode, the latter being preferably placed as low as is
convenient.
When an electrode employed in my invention is liable to disintegration, as for
example when a block of filtering carbon is employed as an anode, I sometimes
encase it in a protecting casing say of fine platinum gauze or punctured platinum
foil. I prefer however to avoid the use of carbon as an anode and to use only
platinum therefor.
In order to adapt my invention for use with currents of different electromotive
force in the case where blocks of filtering material are used I cause the block, or
the other electrode as the case may be, to be adjustable on its support so that the
two electrodes may be placed at the desired distance from one another.
In the case wherein loose or finely divided filtering material is employed, I adjust
the distance between the electrodes by interposing one of the electrodes, preferably
the anode, in the said filteriug material at a greater or less distance from the other
electrode.
In Figure I have shown the block A as of a common form employed in
ordinary domestic filters. Such a form is however a bad one when used as the

page_text: cathode as illustrated. It will be seen that the hydrogen would collect on the
under surface of the said block and increase the resistance between the two
electrodes. When used as a cathode with such a form of anode as is shown the
block should be more or less wedge shaped, and tapering from above to a point or
edge downwards, so as not readily to collect a layer of hydrogen.
The form of anode shown in Figure 2 is not one that should be employed in
ordinary cases as it is liable to mechanical injury. In some cases however as when
the compartment A is not frequently opened up and when water is supplied to it by
a pipe, this form is applicable.
In the diagrams accompanying this Specification I have for convenience of
drawing simply shown the wires connecting the electrodes as passing through the
case of the apparatus. It will of course be understood that in practice if the
conducting wires are led through the body of the filter case, it would have to be
done in one of the usual well known ways of leading a conducting wire through a
similar obstacle in an insulated and waterproof manner. A convenient way of
bringing the wires to the electrodes, especially in the compartment containing the
filtered liquid, is through the air tube constructed in the body of the filter case, or
through a tube or tubes similar to the air tube.
In practice I prefer to construct the conducting wires whenever they are in
contact with the water of platinum. If the said wires be composed of oxidizable
metal or metal liable to be acted upon by or to act upon the water, then the said
wires should be carefully covered or coated with a material such for example as.
gutta-percha which will not interfere with the purity of the water.
It will of course be understood that in such an arrangement as that shown in
Figure 3 the electrodes or the wires leading to them must be carefully insulated
from one another and from the block. In the case illustrated by Figure 4 the
electrode enclosed by the block and its conducting wire must be carefully insulated
from the said block.
A filter consisting of the usual elements that is to say a case or containing vessel,.
a compartment for containing the water to be filtered and a compartment for
containing the filtered water, the said compartments being separated by filtering
material which may or may not be in a compartment separate from the other
compartments, I shall hereinafter call when fitted with electrodes as herein before
mentioned an "electrolytic filter."
I employ the term compartment in its wide sense and include therein a pipe or
tube or channel.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1. An electrolytic filter substantially as set forth.
2. In an electrolytic filter the use of a conducting filtering material or block as
an electrode.
3. The method of adapting an electrolytic filter for currents of different electro-
motive force substantially as set forth.
4. The arrangement and combination of parts substantially as set forth with
reference to Figure 1.
5. The arrangement and combination of parts substantially as set forth with
reference to Figure 2.
6. The arrangement and combination of parts substantially as set forth with
reference to Figure 3.
7. The arrangement and combination of parts substantially as set forth with
reference to Figure 4.
8. The arrangement and combination of parts substantially as set forth with
reference to Figure 5.
9. The arrangement and combination of parts substantially as set forth with
reference to Figure 6.

page_text: 10. The improvement connected with filters which consists in employing in the
compartment for containing the filtered water a float or floats to which electrodes
are attached.
11. The improvement connected with filters which consists in employing in the
compartment for containing the filtered water a float or floats consisting of
conducting material constituting one of the electrodes.
12. The arrangement and combination of parts substantially as set forth with
reference to Figure 7.
13. The arrangement and combination of parts set forth with reference to
Figure 8.
14. The arrangement and combination of parts set forth with reference to
Figure 9.
15. The arrangement and combination of parts set forth with reference to
Figure 10.
16. The arrangement for supporting the electrodes substantially as set forth with
reference to the anode in Figure 1.
Dated this 17th day of March 1893.
J. G. LORRAIN.