Improvements in the Filtration of Liquids.
Year: 1895

page_text: Date of Application, 6th Sept., 1895
Complete Specification Left, 3rd July, 1896-Accepted, 8th Aug., 1895
Improvements in the Filtration of Liquids.
We WALTER JOHN LOMAX and CHARLES JAMES LOMAX both of 11 Foll
Street, Bolton, in the County of Lancaster, Surveyors, do hereby declare the
nature of this invention to be as follows:-
Our said invention relates to improved methods of filtering water, sewage and
other impure liquids in such a manner as to secure repeated and regular oxygenation
or aeration of the filter bed, while at the same time providing for the uniform an
complete distribution of the liquid over the whole filtering surface without
disturbance of the finer material or layers composing the surface of the filter bed.
In carrying our invention into effect we prefer to construct the filter bed circular
in form with a circular tank or flushing chamber in the centre from which the
liquid is automatically discharged at regular and surcessive intervals. The filter
bed and central tank might of course be of other shapes but we prefer the circular
form because the central tank is then equi-distant from the circumference and the
liquid when discharged upon the filter occupies an annular space of equal width
all round so that the liquid is equally distributed. Instead of being in the centre
of the filter bed as described the discharging and distributing tank might be at
the side, end or other part of the filter. Within the discharging tank we place a
syphon or syphous or other automatic discharging valves or means so arranged
that when the liquid admitted to the tank has reached a certain level, the liquid is
automatically discharged upon the filter bed.
To provide for the equal distribution of the discharged liquid over the filter
bed, we arrange a series of radial conduits extending from the discharging tank to
the circumference of the filter bed on to the ends or sides of the same. The
discharged liquid overflows from these conduits over the filter surface.
In sinking through the bed the liquid displaces the air therein and draws air
after it. The body of the filter bed may be composed of layers of any suitable
materials the sand or other fine surface material being covered wholly or in part
with spar gravel, stone chippings, canvas, fibrous material, wickerwork, netting,
gauze, perforated plates or slabs or other suitable materials. The liquid when it
has sunk through the filter bed falls into conduits or into a space beneath sloping
towards the centre or towards a central or common chamber situated beneath the
discharging tank for example. In this chamber also there is a syphon or other
suitable automatic discharging means so that when the liquid in this chamber
reaches a certain height the contained water is again discharged and run away.
In this second chamber there is an air space. As the liquid rises in the chamber
the air is pressed out and upwards through the filter bed, or it might be through a
valve or valves. When the liquid is automatically discharged from the said lower
chamber in the described manner a partial vacuum is created in the chamber and
to supply this, air is drawn down through the filter bed until a balance of
atmospheric pressure is obtained. Thus there is both expiration and inspiration
of air through the filter bed, or in other words the filter bed may be said to breathe.
Thus by the to and fro passages of air the filter bed is thoroughly aerated or
oxygenated. To assist in the circulation and permeation of the air we may place
suitable ventilating boards or appliances in the upper part of the filter.

page_text: Although we have described the action of the improved filter bed as automatic
the operations might be effected manually or by other power although we of course
prefer the automatic action.
If it were found preferable the filter bed might be arranged without the under
chamber and described means of discharge, in which case the aeration of the bed
would depend on the intermittent application of the liquid as previously described.
Dated this 5th day of September 1895.
Improvements in the Filtration of Liquids.
We WALTER JOHN LOMAX and CHARLES JAMES LOMAX both of 11 Fold
Street, Bolton, in the County of Lancaster, Surveyors, 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 and
accompanying drawings:-
Our said invention relates to improved methods of filtering water, sewage and
other impure liquids in such a manner as to secure repeated and regular oxygenation
or aeration of the filter bed, while at the same time providing for the uniform and
complete distribution of the liquid over the whole filtering surface without
disturbance of the finer material or layers composing the surface of the filter bed.
In carrying our invention into effect we prefer to construct the filter bed circular
in form with a circular tank or flushing chamber in the centre from which the
liquid is automatically discharged at regular and successive intervals. The filter
bed and central tank might of course be of other shapes but we prefer the circular
form because the central tank is then equi-distant froin the circumference and the
liquid when discharged upon the filter occupies an annular space of equal width all
round so that the liquid is equally distributed. Instead of being in the centre of
the filter bed as described, the discharging and distributing tank might be at the
side, end or other part of the filter. Within the discharging tank we place a
syphon or syphons or other automatic discharging valves or ineans so arranged
that when the liquid admitted to the tank has reached a certain level, the liquid is
automatically discharged upon the filter bed.
°
To provide for the equal distribution of the discharged liquid over the filter
bed, we arrange a series of radial conduits extending from the discharging tank to
the circumference of the filter bed or to the ends or sides of the same.
discharged liquid overflows from these conduits over the filter surface.
The
In sinking through the bed the liquid displaces the air therein and draws air
after it. The body of the filter bed may be composed of layers of any suitable
materials the sand or other fine surface material being covered wholly or in part
with spar gravel, stone chippings, canvas, fibrous material, wickerwork, netting,
gauze, perforated plates or slabs or other suitable materials. The liquid when it
has sunk through the filter bed falls into conduits or into a space beneath, sloping
towards the centre or towards a central or common chamber situated beneath the
discharging tank for example. In this chamber also there is a syphon or other
suitable automatic discharging means so that when the liquid in this chamber
reaches a certain height, the contained water is again discharged and run away.
In this second chamber there is an air space. As the liquid rises in the chamber
the air is pressed out and upwards through the filter bed, or it might be through a
valve or valves. When the liquid is automatically discharged from the said lower
chamber in the described manner, a partial vacuum is created in the chamber and
to supply this, air is drawn down through the filter bed until a balance of

page_text: atmospheric pressure is obtained. Thus there is both expiration and inspiration
of air through the filter bed, or in other words the filter bed may be said to breathe.
By these to and fro passages of air the filter bed is thoroughly aerated or
oxygenated. To assist in the circulation and permeation of the air or to assist in
getting rid of the air without disturbance of the filter bed surface we may place
suitable ventilating boards or appliances in the upper part of the filter.
To render our invention perfectly clear we will now proceed to describe the
same more particularly, reference being had to the annexed sheet of illustrative
drawings.
Fig. 1 of the said drawings is a vertical cross section of our improved filtering
arrangement.
Fig. 2 is a plan of the same.
We make the enclosed filter bed a perfectly circular in form with a boundary
wall or curb and in the centre we place the flushing tank c also of a circular
shape.
Within the flushing tank e we place several syphons or we might have one
central syphon. The sewage or other liquid to be filtered is run into the flushing
tank continuously through the conduit e and when the liquid reaches a certain level
in the tank c the syphons d act automatically so as to discharge the contents of
the tank through the outlets d' into the radial troughs whence the liquid over-
flows upon the filter bed. The portions of the filter bed bordering upon the
overflow troughs, are covered with strips k of canvas or other permeable material
to prevent disturbance of the surface at these points by the water falling upon or
scouring over the sand. Instead of the said cauvas strips & we might protect the
surface of the filter bed on each side of the overflow troughs (or wherever the
water overflows or falls upon the sand surface so as to tend to disarrange the same)
by coverings of any suitable fibrous materials, wickerwork, wire gauze, or the like
or by top dressings or layers of spar, gravel or stone chippings or by perforated
or pervious slabs plates or the like, the object in all cases being to protect the
sand or fine top layer of the filter bed from the denuding or scouring effects of
the rush or fall of water, by a protecting face which will readily admit of the
passage of water and air while preventing displacement of the sand
surface.
on the
In sinking through the filter bed the liquid displaces the air in the materials and
as this air tends to rise it is apt to pit the sand surface of the filter bed and t
cause bubbles in the liquid.
To prevent this we provide ventilating means for allowing the air to escape
without passing through the water. The said ventilating means consist of two
boards set side by side with a space between as shown in section at Fig. 3. These
boards are set on edge through the sand surface so as to rest on the "polarite" or
coarser material beneath. Therefore when the air is displaced by the descending
liquid it passes through the polarite to the points of least resistance viz. to the
spaces between the said boards f where it escapes. As indicated in Fig. 3 the
boards stand high enough above the sand surface to overtop the water on
the filter bed surface. Thus the water has no access between the boards.
shown in Fig. 2 several of these board ventilators are disposed in the filter bed.
The filter bed is composed of a surface of sand a¹ and beneath the same a layer a 2
of "polarite
or other suitable material but preferably a magnetic oxide of
The lower layer rests upon a bottom of wickerwork a 3 or other perforated
or pervious supporting skin.
iron.
As
Beneath the bottom a 3 is an annular space m sloping towards the centre and
discharging into a chamber beneath the flushing tank cas clearly appears in the
sectional view Fig. 1.
Bricks or supports p serve to carry the wickerwork bottom and filtering
materials above.
The liquid which is discharged upon the filter bed from the contral tank e sinks
through the filtering materials into the sloping aunular space m, from which it

page_text: runs into the lower central chamber the upper part of which constitutes an air
space. In this chamber there is also a syphon 'n or syphons so that when the
liquid in the chamber reaches a fixed level, the contents of the chamber are
in turn automatically discharged by the syphon or syphons a into the conduit o by
which the filtered liquid is led away to the outflow. The reasons for this double
arrangement are as follows. In the first place the liquid discharged at intervals
from the upper flushing tank cupon the filter bed sinks down through the filter
bed displacing the air therein and drawing air after it. As it permeates through
the filter bed and fills the lower chamber, the air in the upper part of the sail
chamber is expelled by the rising level of the liquid in the chamber and is
practically forced upward through the filter bed. Thus there is expiration of air
upward and through the filter bed.
The liquid having now permeated through the filter bed and filled the lower
chamber to the required level, the syphon 'n comes into action and the water in
the lower chamber is suddenly discharged to the outflow o. This sullen with-
drawal of the liquid contents of the chamber 1. creates a partial vacuum therein
and causes air to be drawn inward and downward through the filter bel to supply
the place of the discharged liquid. Thus there is inspiration of air downward
through the filter. In other words by the automatic action herein before describel,
the air is regularly expired and inspired through the älter bed which may thus be
said to breathe. The said up and down currents or movements of air have the
effect of more thoroughly oxygenating or aerating the filter bed.
Although we have described the action of the improved filter bed as automatic,
the operations might be effected manually or by other power although we of course
prefer the automatic action.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is.
1. The general arrangement construction and combination of filter, for the
purposes and substantially as described and illustrated.
2. The breathing filter having a secondary lower receiving and discharging
chamber by the action of which air is forced up or expired, and also drawn down
or inspired through the filter bed substantially as described and as illustrated.
3. A filter bed having a central or other suitably situated flushing tank provided
with flushing appliances and beneath the filter bed an annular space communicating
with a lower central chamber, also furnished with Hushing appliances by the
united action of which air is inspired and respired through the filter bed, for
the purposes, by the means and substantially as hereinbefore described and
illustrated.
4. In combination with the overflow distributing troughs such as g, or with other
similar or suitable water distributing appliances, the protecting permeable surfaces
or coverings for the filter bed on each side of the said troughs, or at the points
where the overflowing or falling water is apt to have a disturbing effect where
water distributing means other than the said troughs are used, the said protecting
permeable surfaces being composed of strips of canvas or fibrous material or fabric
or of wire netting, gauze or wickerwork or layers of spar, gravel, stone chippings,
or perforated plates or slabs or any other suitable means which will give the
described protection and permeable surface substantially as described and
as partly illustrated.
Dated this 2nd day of July 1896.