Improvements in Filters.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in Filters.
A communication from abroad by JEAN AUGUSTE MAIGNEN, a Citizen of France,
residing in the City and County of Philadelphia, State of Pennsylvania,
Manufacturer.
We, MAIGNEN'S FILTRE RAPIDE AND ANTI-CALCAIRE COMPANY LIMD., of
15, Great Marlborough Street, Regent Street, London, W., Manufacturers, do
hereby declare the nature of this invention to be as follows:-
This invention relates to certain improvements in filters, wherein the filtering
materials are disposed in layers, as in the so-called natural sand filters, or in
the so-called mechanical filters in which the water passes through sand beds or
other beds of granular material, the object being to provide in a filter of this
character an artificial or inorganic filtering membrane on the surface of the
layers thereof for the protection of the same, thereby attaining quicker and
better purification of the water, and easier and more economical removal of
the sediment.
The invention also provides means whereby the materials composing said
artificial filtering membranes, may be automatically and evenly distributed all
over the filter bed, and protected from disturbance by the avoidance of extreme
and local currents.
1
The invention contemplates also the use of novel and effective means for con-
veniently removing the said artificial filtering membrane and sediment arrested
thereon, cleansing the surface of the beds and economically sterilizing the whole
body of the filtering materials.
In existing sand beds the impurities suspended in the water form what is
called natural filtering membrane, and until this membrane has acquired a
certain thickness, the water is considered imperfectly filtered and is allowed to
go to waste, and as it passes through the underlaying strata in this imperfectly
purified state, it leaves therein a portion of its impurities, which may after-
wards soil the filtering water.
The mud resting directly on and in the sand, a great quantity of the latter
has to be removed to separate the two by washings, hence a great deal of labor.
In mechanical sand filters the whole sand is more or less stirred up and mixed
with the mud, hence a great waste of power occurs in some cases of filtered
-water.
In the old filter the speed of filtration is regulated by an outlet valve at the
lower part of the beds. This valve is at first slightly opened, and afterwards
opened a little more every now and then, according to the increasing thickness
of the mud deposit. A mistake on the part of the workman who attends to
this valve, may have a most disastrous effect. If he opens it too much there is
a rush through, which creates cracks and fissures and fouls the filtrate and bed
itself for several days. This interference with the natural flow of the water
through the filter during its working period is a most grave error.

page_text: This invention provides, in lieu of the natural muddy filtering membrane,
an artificial or inorganic filtering membrane composed of asbestos fibres or
other fibres, or pulp or powdered asbestos, powdered coke, powdered charcoal,
powdered clinker or a mixture of these or analogous fibres, powdered or in-
soluble materials, of such size and density as to be carried in by the water going
into the filter or otherwise deposited in an even and regular manner all over
the filtering surface, in any convenient manner, the effect of which is that the
mud will be retained upon the surface of the inorganic filtering membrane, and
its penetration into and consequent fouling of the sand or other filtering
material beneath it is prevented.
The invention further consists in the novel features of construction and
arrangement of parts, all as will be hereinafter described.
To carry the invention into effect a filter bed is provided composed of sand
or other filtering material, which is arranged in layers upon suitable founda-
tions, the whole being contained within an enclosure of any desired character.
A trough is located at one side of the exterior of the outside walls or enclo-
sure, the said trough constituting the inlet for the water which passes through
orifices, into transversely arranged troughs, where it discharges itself through
the perforations located in the side walls of the said transverse troughs into the
filter in an even and gradual manner. The orifices are provided with doors or
valves, where by communication between the troughs may be temporarily shut
off when desired.
The transversely arranged troughs are disposed at convenient intervals apart
throughout the entire filter surface, preferably in pairs, and beneath each pair
of troughs is located a partition or divisional wall, which extends up from the
bottom of the filter and thus serves to divide the filter up into sections.
Instead of the troughs just described, we may substitute a rectangular or
other coil of pipes, or we may arrange pipes diagonally across the filter, or in
any other manner, in order that an even distribution of the water over the
entire surface of the filter will result.
Another trough is located at the opposite side of the enclosure, and commu-
nicates through pipes, with the interior of the bottom of the enclosure, through
which latter the filtered water passes into the said latter trough from whence
it may be carried away.
The filtering material destined to form the artificial membrane may be of
asbestos fibres, paper fibres, wood fibres, or mineral fibres, or powdered asbestos,
or pulverised coke clinker, charcoal, stone, stoneware debris, or any mineral
and of any set size and density as to be easily carried in suspension in the
water, and to spread itself easily over the sandy or other granular filtering bed,
where it forms a substantial and effective filtering membrane.
The filtering membrane having been properly formed, the water will pass
therethrough and down through the sand or granular layers out through the
said pipes into the said latter trough, as before described. The draw off pipe is
provided with a grate or valve which may be opened to discharge some of the
water in order to test the quality of the filtrate before it is permitted to rise up
into the side trough.
A receptacle or reservoir is located in convenient proximity to the enclosure,
and preferably, but not necessarily, beneath the ground-the same being pro-
vided with a pipe, one end of which is adapted to connect with the draw off
pipe, while the other end connects with a suitable pump by means of which the
sterilizing liquid is raised from the reservoir through a pipe which connects
therewith, from whence it passes into the filter.
During this operation a gate or valve located at the upper end of the vertical
pipe, which during the process of filtration, remains open, will be closed, and
the sterilizing liquid after filling the filter is allowed to remain therein, the
time necessary for saturating and sterilizing it, after which it may be permitted
to escape through the draw off pipe or at any other convenient place to the

page_text: said receptacle, whence it may be taken for sterilizing other sections of the
filter.
A governing valve is arranged to regulate the supply of sterilizing liquid as
well as to shut off communication between the reservoir and filter when desired
or necessary.
Another pipe is arranged from the external receptacle or reservoir, and con-
nects with the filter by the branch pipe through which latter a sterilizing
liquid, having been used to sterilize one section of the filter as described, may
be allowed to drain into the reservoir from whence it may be raised by said
pump and introduced into the next succeeding section to sterilize it, which
operation is repeated until the entire filter has been thoroughly and economi-
cally sterilized, as will be evident. Valves are also arranged upon these branch
pipes for the purpose of controlling, and properly directing, the sterilizing
liquid to accomplish the desired effect, as will be understood.
Wash-out or over-flow pipes are arranged in any desired number and location
throughout the filtering bed, each being provided at or near its upper extremity
with two valves adapted to cover orifices one of which is arranged on a level
plane on the top of the filter bed, and the other somewhat above it. The valves
are closed during the process of filtration, but are open one after the other
while the bed is being cleansed in order that the muddy sediment which has
accumulated upon the surface of the filtering membrane, in fact the organic
membrane itself, may pass out through said orifices into some convenient recp-
tacle, where it may be washed and afterwards used again upon the filter bed in
a similar manner to that first described, it being evident, of course, that the
lighter particles will rise and pass out through the upper orifice, while the
washing goes on, the lower orifice serves to drain the last of the floating matter.
The removal of the artificial membrane and the cleansing of the filter is
effected by a strong jet or stream of water upon the surface and to accomplish
this a suitable superstructure is arranged over and around the enclosure, from
which a circuitous or other track is suspended extending over the whole area
of the filter, and upon which a carriage can travel, being adapted to seat and
carry an attendant, who, being supplied with a hose can apply water to the
surface.
The operation of cleansing is substantially as follows:-
One set of gates having been closed to prevent the inflow of unfiltered water,
and the other set of gates being partly opened, the filtered water contained in
the outlet will flow back to the pipes entering beneath the filter bed, and the
water rises slowly through the sand or other granular bed.
At that particular time the hose under pressure is made to play on the arti-
ficial membrane which is then loosened and made to pass through the orifices
of the pipe or pipes which have been previously uncovered, and from thence
conducted to any suitable receptacle as previously stated.
A modified form of washing or cleansing attachment may be arranged wherein
the enclosure is provided with a plurality of revolubly-arranged partitions each
of which is carried by a shaft suitably journaled, the outer end being provided
with a cog-gear, the teeth of which engage the teeth of the transversely-arranged
rack, the latter extending beyond the outside of the outer troughs, where its
terminals are formed into handles by which the said partitions may be opened
or closed. It is evident, however,-that-these-handles_may be omitted and any
suitable mechanical device substituted therefor.
The partitions are further provided on each side with rails upon which a
travelling hose-carriage moves and throws water over the surface of the filter-
ing membrane between the partitions, thus cleansing the surface of the filter
in sections as will be obvious. The sides of the enclosure are also provided
upon the interior thereof with corresponding rails, so that the hose-carriage
may be used to cleanse the space between the sides or the first and last parti-
tions as the case may be. A manipulation of the rack to the left will serve to

page_text: rotate the partitions and closing one upon the other, from a substantial covering
against the entrance of leaves, dust, or other foreign elements into the filter-
bed as well as protection against the heat of the sun.
The relative level of the filtered and unfiltered water is arranged to be never
higher than 1' 6" while in working order.
It will thus be seen that the invention provides in a comparatively simple
and inexpensive manner, a filter which is particularly well adapted for the pur-
poses intended, which by reason of the filtering membrane being formed in a
very short space of time, permits of the filtered water being used practically at
once, without waste, the maximum speed being attained and the filtration going
on without any mechanical interference during the whole working period. It is
also obvious that the cleansing and sterilizing operation are both efficacious
and economical, while the filtration is such as to insure thorough purification
of the water.
The I 1
C
1000
FELL & JAMES,
1, Queen Victoria Street, London, E.C.,
Agents for the Applicants.
A communication from abroad by JEAN AUGUSTE MAIGNEN, a Citizen of France,
residing in the City and County of Philadelphia, State of Pennsylvania,
United States of America, Manufacturer.
We, MAIGNEN'S FILTRE RAPIDE AND ANTI-CALCAIRE COMPANY LIMITED, of
15, Great Marlborough Street, Regent Street, London, W., Manufacturers, 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 follow-
ing statement:-
This invention relates to certain improvements in filters, wherein the filtering
materials are disposed in layers, as in the so-called natural sand filters, or in
the so-called mechanical filters in which the water passes through sand beds or
other beds of granular material, the object being to provide in a filter of this
character an artificial or inorganic filtering membrane on the surface of the
layers thereof for the protection of the same, thereby attaining quicker and
better purification of the water, and easier and more economical removal of
the sediment.
The invention also provides means whereby the materials composing said
artificial filtering membranes, may be automatically and evenly distributed all
over the filter bed, and protected from disturbance by the avoidance of extreme
and local currents.
The invention contemplates also the use of novel and effective means for con-
veniently removing the said artificial membrane and sediment arrested thereon,
cleansing the surface of the beds and economically sterilizing the whole body
of the filtering materials.
In existing sand beds the impurities suspended in the water form what is
called natural filtering membrane, and until this membrane has acquired a
certain thickness, the water is considered imperfectly filtered and is allowed to
go to waste, and as it passes through the underlaying strata in this imperfectly
purified state, it leaves therein a portion of its impurities, which may after-
wards soil the filtering water,

page_text: The mud resting directly on and in the sand, a great quantity of the latter
has to be removed to separate the two by washings, hence a great deal of labour.
In mechanical sand filters the whole sand is more or less stirred up and mixed
with the mud, hence a great waste of power occurs in some cases of filtered
water.
In the old filter the speed of filtration is regulated by an outlet valve at the
lower part of the beds. This valve is at first slightly opened, and afterwards
opened a little more every now and then, according to the increasing thickness
of the mud deposit. A mistake on the part of the workman who attends to
this valve, may have a most disastrous effect. If he opens it too much there is
a rush through, which creates cracks and fissures and fouls the filtrate and bed
itself for several days. This interference with the natural flow of the water
through the filter during its working period is a most grave error.
This invention provides. in lieu of the natural muddy filtering membrane,
an artificial or inorganic filtering membrane composed of asbestos fibres or
other fibres, or pulp or powdered asbestos, powdered cork, powdered charcoal,
powdered clinker or a mixture of these or analogous fibres. powdered or in-
soluble materials, of such size and density as to be carried in by the water going
into the filter or otherwise deposited in an even and regular manner all over
the filtering surface, in any convenient manner, the effect of which is that the
mud will be retained upon the surface of the inorganic filtering membrane, and
its penetration into and consequent fouling of the sand or other filtering
material beneath it is prevented.
The invention further consists in the novel features of construction and
arrangement of parts, all as will be hereinafter described and pointed out in
the claims.
Referring to the drawings.
Figure represents a sectional perspective view of a filter having this inven-
tion applied thereto.
Figure 2 represents a transverse section taken on the line of Figure 1.
Figure 3 represents a sectional perspective view of a modified form of filter
to be described.
Similar letters of reference indicate corresponding parts in the figures.
A designates a filter bed composed of sand or other filtering material, which
is arranged in layers upon suitable foundations, the whole being contained
within an enclosure B of any desired character.
C designates a trough located at one side of the exterior of the outside walls
or enclosure B, the said trough constituting the inlet for the water which passes
through orifices D, into transversely arranged troughs E where it discharges
itself through the perforations F located in the side walls of the said trans-
verse troughs into the filter in an even and gradual manner. The orifices D
are provided with doors or valves G. whereby communication between the
troughs C and E may be temporarily shut off when desired.
The transversely arranged troughs E are arranged at convenient intervals
apart throughout the entire filter surface, preferably in pairs as shown, and
beneath each pair of troughs is located a partition or divisional wall, which
extends up from the bottom of the filter and thus serves to divide the filter up
into sections.
Instead of the troughs E just described, we may substitute a rectangular or
other coil of pipes, or we may arrange pipes diagonally across the filter, or in
any other manner, in order that an even distribution of the water over the
entire surface of the filter will result.
H designates a trough located at the opposite side of the enclosure B, and
communicating through the pipes I and J, with the interior of the bottom of
the enclosure, as clearly shown, through which latter the filtered water passes
into the said latter trough H from whence it may be carried away.
The filtering material destined to form the artificial membrane may be of

page_text: asbestos fibres, paper fibres, wood fibres, or mineral fibres, or powdered asbestos,
or pulverized coke clinker, charcoal, stone, stone ware debris or any mineral
and of any set size and density as to be easily carried in suspension in the
water, and to spread itself easily over the sandy or other granular filtering
bed A where it forms a substantial and effective filtering membrane.
The filtering membrane having been properly formed, the water will pass
therethrough and down through the sand or granular layers out through the
pipes and I into the trough H, as before described and the pipe J is pro-
vided with a grate or valve K which may be opened to discharge some of the
water in order to test the quality of the filtrate before it is permitted to rise
up into the trough H.
L designates a receptacle or reservoir which is located in convenient proxi-
mity to the enclosure B, and preferably, but not necessarily, beneath the
ground, the same being provided with a pipe M, one end of which is adapted
to connect with the pipe J, while the other end connects with a suitable
pump M by means of which the sterilizing liquid is raised from the reservoir
through a pipe M² which connects therewith, from whence it passes into the
filter.
During this operation a gate or valve N located at the upper end of the ver-
tical pipe I, which during the process of filtration, remains open, will be closed,
and the sterilizing liquid after filling the filter, is allowed to remain therein,
the time necessary for saturating and sterilizing it, after which it may be per-
mitted to escape through the pipe or at any other convenient place to the said
receptacle L, whence it may be taken for sterilizing other sections of the filter.
A governing valve P is arranged upon said pipe M to regulate the supply of
sterilizing liquid as well as to shut off communication between the reservoir
and filter when desired or necessary.
Q designates a pipe which leads from the external receptacle or reservoir L,
and connects with the filter by the branch pipe Q through which latter a
sterilizing liquid, having been used to sterilize one section of the filter as
described, may be allowed to drain into the reservoir from whence it may be
raised by said pump and introduced into the next succeeding section to sterilize
it, which operation is repeated until the entire filter has been thoroughly and
economically sterilized, as will be evident. Valves are also arranged upon
these branch-pipes Q₁ for the purpose of controlling, and properly directing,
the sterilizing liquid to accomplish the desired effect, as will be understood.
R designates washout or overflow pipes which may be arranged in any desired
number and location throughout the filtering bed A, each being provided at or
near its upper extremity with two valves S, T, adapted to cover orifices U, V.
of which the former is arranged on a level plane on the top of the filter bed,
the latter somewhat above it. The valves are closed during the process of filtra-
tion, but are open one after the other while the bed is being cleansed in order
that the muddy sediment which has accumulated upon the surface of the filter-
ing membrane, in fact the inorganic membrane itself, may pass out through
said orifices into some convenient receptacle, where it may be washed and after-
wards used again upon the filter bed in a similar manner to that first described.
it being evident, of course that the lighter particles will rise and pass out
through the upper orifice, while the washing goes on, the lower orifice serves
to drain the last of the floating matter.
The removal of the artificial membrane and the cleansing of the filter is
effected by a strong jet or stream of water upon the surface and to accomplish
this a suitable superstructure B2 is arranged over and around the enclosure B
from which a circuitous or other track W, is suspended, extending over the
whole area of the filter, and upon which a carriage X travels, being adapted to
seat and carry an attendant, who, being supplied with a hose Y applies water
to the surface.

page_text: The operation of cleansing is sustantially as follows:
The gates G having been closed to prevent the inflow of unfiltered water, and
the gates N of the trough H being partly opened, the filtered water contained
in the outlet trough H will flow back by the pipes I and J, entering beneath
the filter bed, and the water rises slowly through the sand or other granular bed,
upon opening the exit valves U and V of the wash out pipe R.
At that particular time the hose under pressure is made to play on the arti-
ficial membrane which is then loosened and made to pass through the orifices U
and V of the pipe or pipes R which have been previously uncovered, and from
thence conducted to any suitable receptacle as previously stated.
In Figure 3 is shown a modified form of washing or cleansing attachment
wherein the enclosure B is provided with a plurality of revolubly-arranged
partitions A', each of which is carried by a shaft B suitably journaled, the
outer end being provided with a cog gear C, the teeth of which engage the
teeth of the transversely-arranged rack D', the latter extending beyond the out-
side of the troughs C and H, where its terminals are formed into handles E' by
which the said partitions may be opened or closed. It is evident however, that
these handles may be omitted and any suitable mechanical device substituted
therefor.
The partitions are further provided on each side with rails F1 upon which a
travelling hose-carriage moves and throws water over the surface of the filtering
membrane between the partitions, thus cleansing the surface of the filter in sections
as will be obvious. The sides of the enclosure are also provided upon the interior
thereof with corresponding rails, so that the hose-carriage may be used to cleanse
the space between the sides or the first and last partitions as the case may be.
A manipulation of the rack D' to the left will serve to rotate the partitions A¹
and closing one upon the other, form a substantial covering against the entrance
of leaves, dust, or other foreign elements into the filter-bed as well as protection
against the heat of the sun.
The relative level of the filtered and unfiltered water is arranged to be never
higher than 16" while in working order.
It will thus be seen that this invention provides in a comparatively simple
and inexpensive manner, a filter which is particularly well adapted for the purposes
intended, which, by reason of the filtering membrane being formed in a very
short space of time, permits of the filtered water being used practically at once,
without waste, the maximum speed being attained and the filtration going on
without any mechanical interference during the whole working period. It is
also obvious that the cleansing and sterilizing operation are both efficacious and
economical, while the filtration is such as to ensure thorough purification of the
water. It is evident that the superstructure shown in Figure 1 may be covered
as shown in dotted lines to exclude the elements.
Although we have herein described and shown the enclosure as a thin rectan-
gular body, it will be understood that this invention will apply to circular filters
and to enclosures whose walls may be of varying thickness, and it is also appa-
rent that the artificial or inorganic membrane may be deposited on any of the
existing mechanical filters as well as on open slow sand filtering beds.
The open troughs may also be omitted, and pipes substituted therefor in
which event, the same will be provided with any ordinary or suitable valves, and
although we have described one particular way of removing the artificial filter-
ing membrane, it is obvious that the same may be allowed to dry and then be
removed by rolling it upon itself, an operation which is particularly easy and
applies to cases where asbestos or other fibres are used alone, or in combination
with powdered materials, as will be understood.
The rails W and partitions A¹ and their adjuncts may be entirely dispensed
with, and instead suitable trolley wires may be strung over the surface upon
which the hose-carriage will travel to and fro during the process of washing.

page_text: Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is: -
1st. In a filter for the purposes described, the artificial or inorganic filtering
membrane composed of asbestos or other fibre, pulp, or asbestos powder, pow-
dered or pulverized coke, clinker or analogous material deposited on the filter
layers.
2nd. In a filter for the purposes described, the artificial or inorganic filtering
membrane, composed of asbestos or other fibres pulp or asbestos powder, pow-
dered or pulverized coke, clinker or analogous material and means for auto-
matically depositing it on the filter layers.
3rd. In a filter for the purposes described, the artificial or inorganic filtering
membrane composed of asbestos or other fibre, pulp or asbestos powder, powdered
or pulverized coke, clinkers or analogous materials of such size and density as
to mix with and be carried by the water and evenly distributed and uniformly
deposited over the surface of the layers.
4th. In a filter for the purposes described, the artificial or inorganic_filtering
membrane, composed of asbestos or other fibres pulp or asbestos powder, pow-
dered or pulverized coke, clinkers or analogous material, the same being of such
size and density as to mix with and be carried by the water on the filter layers,
and evenly distributed and uniformly deposited over the surface thereof," and
means for sterilizing and cleansing the filter.
5th. A filter for the purposes described, comprising a filter of sand or other
granular material, a filtering membrane composed of asbestos or other fibre,
pulp or asbestos powder, or powdered or pulverized coke, clinker or analogous
material, perforated troughs or pipes arranged above the filter beds through
which the incoming water is admitted to the filter and evenly distributed over
the entire surface thereof.
6th. A filter for the purposes described comprising a sand or other granular
layers, an enclosure for the same, an inlet for the incoming water, suitably
arranged perforated troughs or pipes communicating with said inlet, and an
artificial or inorganic filtering membrane, composed of asbestos or other fibre,
pulp or asbestos powder or powdered or pulverized coke, clinker or analogous
material of such size and density as to commingle with and be carried by the
water and uniformly distributed and deposited on the surface of the filter
layers.
7th. A filter for the purposes described comprising a sand or other granular
layer, an enclosure for the same, an inlet for the incoming filtered water, per-
forated pipes or troughs communicating with said inlet, gates or valves to shut
off communication between said inlet and perforated troughs, an artificial or
inorganic filtering membrane composed of asbestos or other fibre, pulp or
asbestos powder, or powdered or pulverized coke, clinker or analogous material
adapted to commingle with and be carried by the water and distributed and
uniformly deposited over the filter bed, and means communicating with said
filter whereby the purified water may be drawn off.
Sth. A filter for the purposes described comprising sand or other granular
layers, an enclosure for the same, inlets for the incoming unfiltered water, per-
forated pipes or troughs communicating with said inlets, and valves or gates to
shut off communication therewith, an artificial or inorganic filter membrane
distributed on and evenly deposited over the surface of said filter, an outlet for
the purified water and means connecting the filter with said outlet.
9th. A filter for the purposes described comprising sand or other granular
layers, an enclosure for the same, an inlet for the incoming unfiltered water,
perforated pipes or troughs arranged above the filter-bed and communicating
with said inlet, an outlet for the purified water, pipes communicating therewith
and leading from the filter-bed, orifices and between said outlet and the interior

page_text: of the enclosure, gates or valves for said orifices, and an artificial or inorganic
filtering membrane distributed on and evenly deposited over the surface of the
filter.
10th. A filter for the purposes described, comprising sand or other granular
layers, an inlet for the incoming unfiltered water, perforated troughs commu-
nicating with said inlet, an outlet pipe for the purified water, pipes communi-
cating with said outlet and leading from the filter, gates or valves for said pipes,
orifices between said outlet and the filter bed, gates or valves for said orifices, a
filtering inorganic or artificial membrane for said filter and wash-out pipes pro-
vided with orifices for the discharge of the filtering membrane and accumulated
sediment when cleansing the same.
11th. A filter for the purposes described, comprising sand or other granular
layers, an inlet and outlet for the filtered and unfiltered water, perforated troughs
communicating with said inlets, pipes leading from the filter to said outlet, gates
or valves for said pipes, orifices between said outlet and perforated troughs and
interior of the filter, gates or valves for said orifices, an inorganic or artificial
filtering membrane for said filter, wash-out pipes having orifices therein for
the discharge of the filtering membrane and impurities, and gates or valves to
cover said orifices.
12th. In combination with a filter of the character described, a receptacle or
reservoir for containing sterilizing liquids, and means connecting said recep-
tacle or reservoir with the filter, whereby the sterilizing liquids may be intro-
duced into the filter and withdrawn therefrom.
13th. In combination with the filter of the character described, a receptacle
or reservoir for containing sterilizing liquids, pipe connections and controlling
valves between said receptacle or reservoir and filter, whereby the sterilizing
liquids or gases may be introduced into and withdrawn from one section of the
filter, and means also communicating with said receptacle or reservoir, whereby
the sterilizing liquids may be conveyed to other sections of the filter.
14th. The combination with a filter of the character described, of a track or
tracks, arranged above the surface of the filter-beds, and extending over the
entire surface thereof and a hose carriage adapted to travel on said track or
tracks to force water pressure upon the filtering surface in sections.
Dated this 14th day of October 1899.
FELL & JAMES,
1, Queen Victoria Street, London, E.C.,
Agents for the Applicants.