Improvements in connection with the Precipitation of Sewage and Polluted Waters, and in Precipitation Tanks, and in Filtering Apparatus, and in Filter Beds for the Purification of Sewage and Polluted Waters.
Year: 1893

page_text: Date of Application, 18th Oct., 1893
Complete Specification Left, 18th Aug., 1894-Accepted, 13th Oct.. 1894
PROVISIONAL SPECIFICATION.
Improvements in connection with the Precipitation of Sewage and
Polluted Waters, and in Precipitation Tanks, and in Filtering
Apparatus, and in Filter Beds for the Purification of Sewage
and Polluted Waters.
I FRANK PULLEN CANDY of 56 Nightingale Lane Balham in the County of
Surrey Sanitary Engineer do hereby declare the nature of this invention to be as
follows:-
My invention consists first in improvements in connection with the precipitation
of sewage and polluted waters and has for its object the thorough and perfect
addition to or admixture in a small area of deodorants precipitants and the like
with the sewage or polluted waters under treatment.
«
The sewage and polluted waters 1 hereafter speak of as sewage."
In providing for the addition of the required chemicals to the sewage I dissolve
it or them if soluble in water or if insoluble reduce to a fine condition and mix with
water until of a sufficiently thin consistency to run easily I then discharge the said
solution or admixture into the sewage through a pipe or its equivalent the exit
mouth of the said pipe entering the sewage below its surface, the flow of the
chemical into the sewage may be either with or against the flow of the sewage or
at an angle for instance so as to produce a rotating or eddying motion the exit
mouth of the said pipe may be reduced in size or may be spread out like a fan or
may be in the form of a rose or of other suitable shape. I sometimes place a
shield such as a disc or a cone in connection with the said exit or exits so as to
prevent it or them becoming choked by any matters in the sewage. At any con-
venient point in the said pipe or in connection therewith I place a sieve or grid so
arranged as to retain any particles that might otherwise choke the exit or exits of
the said pipe.
In providing for the thorough admixture of the chemical with the sewage I
construct a tank or receptacle preferably rectangular and cause the sewage to flow
through it with an up and down or backward and forward motion by means of
suitable divisions placed within the said mixing tank. I sometimes place or form
bafflers or obstructions in these divisions for instance the divisions may be
corrugated at or about right angles to the flow of the sewage. The flow of the
sewage through these said mixing tanks must be sufficiently rapid to prevent the
coagulum being deposited in them. The sewage may enter either at the top or
bottom of the said mixing tanks but the tank is so arranged as to be always full of
sewage when working a mixing tank of a capacity equal to about one to two
minutes flow of the sewage is I find suitable. I sometimes provide the bottom of
the said mixing tanks with an outlet for drawing off any heavy solids that may
deposit thereon, the said bottom being then preferably cone shaped. The chemical
should be added to the sewage before or during its entrance into the said mixing
tauks.
My invention consists further of the improvements hereafter described in pre-
cipitation tanks and relates especially to upward flow precipitation tanks my object
being to cause the sewage to flow through a deposit or accumulation of sludge
which shall act as a filter for or as an aggregator of the smaller particles of
suspended matter.
sometimes accomplish this by causing the sewage to enter the precipitation

page_text: 66
tank below the normal level of the sludge so that the sewage shall flow through
the said sludge. The sewage may enter the precipitation tank through a pipe or
pipes or by means of a diaphragm or diaphragms with preferably a downward flow
of exit into the tank. Or I sometimes surround the downwardly flowing inlet of
the sewage with a cone cup or other suitable receptacle, hereafter called the
receptacle," having a bottom but the top being open the said receptacle is of such
a size and so arranged that when the tank is working it shall be full of sludge
through which the sewage has to pass before dispersing into the precipitation tank
the receptacle continually having fresh sludge added to it and sludge continually
falling over the side of the receptacle to the bottom of the precipitation tank. Or
as a modification I cause the sewage to enter at the bottom of the said receptacle
or I form the receptacle of an enlargement of the upwardly flowing inlet of the
sewage so that the said receptacle or the said enlargement shall be when working
full of sludge.
Instead of the aforesaid receptacle being in the form of a cup cone or the like I
sometimes employ one of a cylindrical or rectangular shape with parallel or tapering
sides both ends being open, the bottom of the said cylindrical or rectangular vessel
coming sufficiently close to the bottom of the tank or to another "bottom" provided
for the purpose to keep an accumulation of sludge in the said vessel.
I sometimes form slots or openings in the sides or bottom of the said receptacle
or its equivalent. The receptacle or its equivalent is placed or situated on or near
the bottom of the precipitation tank. I sometimes provide flanges on the outside
of the sewage inlet pipe particularly if the same is carried down within the
receptacle and also sometimes place flanges on the inside of the receptacle or its
equivalent in order to prevent a flow along the sides and I sometimes also place
large downwardly sloping flanges on the outside of the receptacle or its equivalent
so that the sludge flowing over its sides shall flow over and along the said large
flanges. I sometimes employ more than one sewage inlet with its receptacle or
equivalent to each precipitation tank.
My invention consists further of improvements hereinafter described in filtering
apparatus the objects of my said improvements being to prevent too rapid choking
up of the filtering material and to provide for the economical working and cleansing
of the filtering medium especially with a small pressure of water.
According to my said improvements I cause the liquid to be filtered, which I
will call the "liquid," to enter the top of the filtering apparatus in such manner
that it shall cause a rotary motion of the liquid above the top of the filtering
material.
The bottom layer or layers of filtering material I form of granules generally
coarse granules of a greater specific gravity than the filtering material
above this said bottom layer for instance granules of iron ore so that the said
bottom layer shall maintain its position when the filter is being cleaned.
For the top of the filtering material I sometimes employ a layer of coarse
filtering medium of a lighter specific gravity than the layer below it for instance
coke granules so that the said top layer shall maintain its position at the top and
shall not become mixed up with the other layer or layers during the cleansing of
the filter. The material I generally use for the middle layer is sand but I some-
times use a material of a less or greater specific gravity than the said sand.
The bottom part of the filtering apparatus I form as follows. A suitable
distance from the bottom of the filter tank I place a strong perforated plate
or plates, which I call the "perforated plate," which bears the weight of the
filtering material this "perforated plate" is supported in any convenient manner its
edges being made water tight against the sides of the filter case or against a flange
thereon, the perforations in the said plate or plates which may be of cast iron are
of a good size for instance three eighths of an inch diameter these perforations are
the requisite distance apart to enable the filtering material to be cleansed by an
upward flow of water alone over these perforations on either side of the "perforated
plate" is or are attached a sheet or sheets of non corroding material such as

page_text: aluminium zinc copper bronze or other suitable alloy according to the nature of the
liquid to be dealt with, this said sheet or sheets is or are also perforated the per-
forations corresponding with the holes in the perforated plate or plates but are of
such a size as is required to enable the filtering material to be cleaned by an
upward flow of water alone perforations about one inch apart and of about one
twentieth to one tenth of an inch diameter I find suitable for the said sheet or
sheets; directly on top of the perforated plate or directly on top of the said
perforated sheet or sheets if the same is or are placed over the perforated plate is
attached in such manner that all the liquid during the washing operation must pass
therethrough a covering of suitable porous perforated or reticulated material such
as copper wire gauze, on the top of the said wire gauze or its equivalent is placed
the filtering material. Instead of placing the wire gauze or its equivalent directly
on the perforated plate or perforated sheet or sheets as beforementioned I some-
times support it on rings bars pillars or the like attached to or formed from the
perforated plate.
As a modification I sometimes support the said perforated sheet or sheets of
non-corroding material by means of bars or grids or in other suitable manner
without the employment of the strong perforated plate and I place the said wire
gauze or its equivalent upon the said perforated sheet or sheets or I sometimes
support the wire gauze or its equivalent a short distance above the perforated
sheet or sheets for instance by the same bars grids or the like that support the
perforated sheet or sheets.
I sometimes dispense with the beforementioned wire gauze or its equivalent
employing only the beforementioned non-corroding perforated sheet or sheets
suitably supported.
I sometimes form an aperture or apertures preferably large for instance from
one inch to six inches in diameter in the beforementioned non corroding perforated
sheet or sheets and if necessary in the beforementioned perforated plate the said
large aperture or apertures being provided with a valve or the like by means of
which it or they can be closed at will or by the upward flow of water when the
filtering material is being cleaned, if necessary I cover the said large aperture with
wire gauze or its equivalent and sometimes perforate the valve.
In the beforementioned perforated plate or perforated sheet or sheets or wire
gauze or its equivalent the liquid when the bed is being cleaned must not be able
to escape round the sides or edges thereof but must pass through the perforations
provided therein for that purpose.
My invention consists further in improvements in filter beds and has for its
object the passing or drawing of air or other suitable gas through the filter bed.
According to my said improvement I form the top part of the filter bed of fine
material and the bottom part of the filter bed of coarse material of such a size that
air or gas, can pass therethrough when the filter bed is working. I provide
ventilating pipe or pipes connected with the said coarse material and with the air
or with a supply of other suitable gas I further provide at or connected with a
suitable part or parts of the filter bed a fan or fans or the like connected with the
said coarse material in such a manner that air or gas can thereby be drawn through
the coarse part of the filter bed.
In purifying sewage by the whole of my invention I first add and mix the
chemical with the sewage in the manners herein before indicated I then pass the
treated sewage through the herein before described precipitation tank then through
the aforesaid filtering apparatus and finally through the aerating filter bed.
Dated this Sixteenth day of October 1893.

page_text: COMPLETE SPECIFICATION.
Improvements in connection with the Precipitation of Sewage and
Polluted Waters, and in Precipitation Tanks, and in Filtering
Apparatus, and in Filter Beds for the Purification of Sewage
and Polluted Waters.
I FRANK PULLEN CANDY of 56 Nightingale Lane Balham in the County of
Surrey Sanitary 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 consists first of improvements in connection with the precipitation
of sewage and polluted waters and has for its object the thorough admixture or
incorporation in a small area of deodorants precipitants and the like with the sewage
or polluted waters under treatment.
66
The sewage and polluted waters I hereinafter speak of as sewage."
According to this part of my invention I construct a tank or receptacle
preferably rectangular and cause the sewage to flow through it with an up and
down or backward and forward motion by means of suitable divisions placed
within the said mixing tank and I place or form bafflers or obstructions in these
divisions for instance the divisions may be corrugated at or about right angles to
the flow of the sewage. The flow of the sewage through these said mixing tanks
must be sufficiently rapid to prevent the coagulum being deposited in them. The
sewage may enter either at the top or bottom of the said mixing tanks but the tank
is so arranged as to be always full of sewage when working. A mixing tank of a
capacity equal to about one to two minutes flow of the sewage is I find suitable.
I sometimes provide the bottom of the said mixing tanks with an outlet for
drawing off any heavy solids such as sand and like matter that may deposit
thereon the said bottom being then preferably sloped downward towards the
middle. The chemical should be added to the sewage before or during its entrance
into the said mixing tanks. After passing through the said mixing tanks the
sewage is passed into tanks or other apparatus in which precipitation or other
required action takes place.
Mixing tanks constructed as herein before described are illustrated in vertical
section in Figures 1, 2 and 3 of the accompanying drawings the divisions or
partitions in the said tanks being marked a in all the said figures. In Figure 1
corrugated partitions are shown and in Figures 2 and 3 arrangements of
baffles in the compartments formed by the partitions are shown the said baffles
being marked bb. The arrows indicate the course of the sewage passing through
the said tanks. Instead of arranging the partitions vertically as illustrated they
may be arranged horizontally or diagonally. In order to obviate accumulation of
sand or other heavy matter in the lower part of the mixing tanks the sewage should
be caused to flow through a catch pit on its way to the said tanks. The bottoms of
the said tanks may however be made to slope towards the middle and provision may
be made for withdrawal of the sludge therefrom.
My invention consists further of the improvements hereinafter described in
filtering apparatus, the objects of my said improvements being to provide for the
economical working and cleansing of the filtering medium especially with a small
pressure of water.
The bottom layer of filtering material I form of granules generally coarse
granules of a greater specific gravity than the filtering material above it (for
instance granules of iron ore) so that the said bottom layer shall maintain its
position at the bottom when the filter is being cleaned. For the top of the
filtering material I sometimes employ a layer of coarse filtering medium of a less

page_text: specific gravity than the layer or layers below it (for instance coke or coal granules)
so that the said top layer shall maintain its position at the top during the cleansing
of the filter. The material I generally use for the middle layer is sand but I some-
times use a material of a less or greater specific gravity than sand. The only
requirement in respect of the middle layer is that it shall be of sufficiently greater
specific gravity than the layer above it and of sufficiently less specific gravity than
the layer below it to ensure its position being maintained during cleaning of the filter
by upward flow of water through the several layers.
The lower part of the filtering apparatus I form as follows;-A suitable
distance from the bottom of the filter tank I place a strong perforated plate or
plates which I call the "perforated plate" which bears the weight of the filtering
material. This perforated plate is supported in any convenient manner its edges
being made watertight against the sides of the filter case or against a flange
thereon. The perforations in the said plate or plates (which may be of cast iron)
are of a good size for instance three eighths of an inch diameter. These perforations
are the requisite distance apart to enable the filtering material to be cleansed by an
upward flow of water alone. Over these perforations on either the upper or under-
side of the perforated plate is or are attached a sheet or sheets of non-corroding
material such as aluminium, zinc, copper, bronze or other suitable metal or alloy
according to the nature of the liquid to be dealt with. This said sheet or sheets is
or are also perforated the perforations corresponding with the holes in the perforated
plate or plates but are of such a size as is required to enable the filtering material
to be cleaned by an upward flow of water alone. Perforations about one inch and
a quarter or one inch and a half apart and of about one twentieth to one tenth of
an inch diameter I find suitable for the said sheet or sheets. Directly on top of the
perforated plate or directly on top of the said perforated sheet or sheets (if the
same is or placed above the perforated plate) a covering of suitable perforated or
reticulated material such as copper wire gauze is placed and the said perforated
sheet or sheets and the said perforated or reticulated material are secured in
such manner that all the liquid during the washing operation must pass there-
through. On the top of the said wire gauze or its equivalent is placed the filtering
material.
Figure 4 of the accompanying drawings is a vertical section of a portion of a
filter illustrating the arrangement of the perforated plate and the perforated sheet
and the wire gauze in which the perforated sheet is above the perforated plate.
c is the tank or containing vessel of the filter. is the perforated plate which is
supported by a flange e projecting from the sides of the tank c. dd are the
perforations in the said plate. fis the perforated sheet of non-corrodible material
and ff are the perforations therein. g is the wire gauze. The parts d f and g
are secured in place by means of a ring hand screws i i. In order to prevent the
perforated sheet and the gauze g from being forced upward by upward pressure
of water while the filter is being cleansed they may be secured to the perforated
plate by means of screws passed through them and engaging in the said perforated
plate or by means of bars of suitable material placed over them and secured to the
said perforated plate by screws or by means of bars placed over the gauze g and
held down by engagement of their ends with recesses in the ring h. The filtering
material (which is not shown in the said Figure 4 or in the other figures of the
accompanying drawings) is placed in the upper part of the vessel e the lowermost
layer of the said material resting on the gauze g. Instead of placing the wire
gauze or its equivalent directly on the perforated plate or perforated sheet or sheets
as hereinbefore described I sometimes support it on rings bars pillars or the like
attached to or formed from the perforated plate.
C
As a modification I sometimes support the said perforated sheet or sheets of non
corroding material by meaus of bars or grids or in other suitable manner without the
employment of the strong perforated plate and 1 place the said wire gauze or its
equivalent upon the said perforated slieet or sheets. Or I sometimes support the
wire gauze or its equivalent a short distance above the perforated sheet or sheets

page_text: for instance by the same bars grids or the like that support the perforated sheet or
sheets.
Figures 5 and 6 of the accompanying drawings are vertical sections of portions
of a filter showing a suitable arrangement of bars for supporting the perforated plate
the said sections being taken in planes at right angles to each other. Figures 7
and 8 of the accompanying drawings are similar sections of portions of a filter
showing the wire gauze supported a short distance above the perforated sheet by
means of bars which also support the perforated sheet the said sheet being secured
to the underside of the said bars. In all the said Figures 5, 6, 7 and 8 the bars
referred to are marked j and are shown supported by a lip el formed on the flange e.
In the said figures and in the other figures hereinafter referred to of the
accompanying drawings the parts already described with reference to Figure 4 are
marked with letters of reference corresponding to those in the said Figure 4.
I sometimes dispense with the before mentioned wire gauze or its equivalent
employing only the before mentioned non corroding perforated sheet or sheets
suitably supported.
I sometimes form an aperture or apertures preferably large (for instance from
one inch to six inches in diameter) in the beforementioned non-corroding perforated
sheet or sheets and also if necessary in the before mentioned perforated plate the
said large aperture or apertures being provided with a valve or the like by means
of which it or they can be closed at will or by the upward flow of water when the
filtering material is being cleaned. The object of the said valve is to provide
against any slowing of the action of the filter consequent on the water passing less
freely through the perforations in the perforated sheet f than through the filtering
material. If necessary I cover the said large aperture with wire gauze or its
equivalent and perforate the valve.
Figure 9 of the accompanying drawings is a vertical section of a portion of a
filter in which a perforated plate or perforated sheet and wire gauze are arranged
as in Figure 4 the said perforated plate and perforated sheet having large
corresponding apertures formed in them and the aperture in the perforated plate
having applied to it a valve so constructed and mounted that it will permit water
to pass freely downward and will be automatically closed by upward flow of water
through the filter. The said valve consists of a perforated plate of non-corrodible
material jointed at to lugs formed on a ring m secured to the underside of the
perforated plate & the underside of which ring is faced with india rubber or other
suitable yielding material n with which the plate k is kept in contact when water is
flowing upwardly through the filter by means of a float or air vessel o which is
secured to the underside of the said valve. 1 prefer to form the float o of non
corrodible material but it may be of iron or other material which will not produce
objectionable contamination of the water. Where desirable the filter may be
provided with two or more valves arranged as hereinbefore described or otherwise
suitably arranged. Instead of providing the valve with a float to ensure closure of
the valve by upward flow of water the said valve may be so balanced by a
counterweight as to rise when not acted on by water passing downward through
the filter.
Figure 10 of the accompanying drawings is a vertical section of a portion of a
filter corresponding to that illustrated in Figure 9 and showing the application of
an ordinary screw down sluice valve to the aperture in the perforated plate. p is the
case of the said valve which is represented in elevation and pl is the rod by which
it is worked which rod passes through a stuffing box q in the side of the vessel c.
The disc by which the passage through the said valve is closed may be perforated
as the sheet is perforated. Any other suitable form of valve may be used.
In all cases the beforementioned perforated plate and perforated sheet or sheets
and the wire gauze or its equivalent must be so secured in place that when the filter
bed is being cleansed by upward flow of water through it the water will not be able
to escape round the sides or edges of the said parts but will pass through the
perforations or openings therein.

page_text: Having now 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. Apparatus constructed substantially as herein before described with reference
to Figures 1, 2 and 3 of the accompanying drawings for use in producing
intermixture of deodorants precipitants and the like with sewage that is to say
apparatus so constructed that the matters flowing therethrough are caused to travel
in alternately reverse directions the passages through which the said matters flow
being contracted at intervals.
Secondly. A filter bed the lowermost layer of which is composed of material of
such specific gravity that the position of the said layer relatively to that next above
it will not be disturbed by upward passage of water through the filter bed for the
purpose of cleansing it.
Thirdly. A filter bed the uppermost layer of which is composed of material of
such specific gravity that the position of the said layer relatively to that next below
it will not be disturbed by upward passage of water through the filter bed for the
purpose of cleansing it.
Fourthly. The arrangement herein before described for supporting the filtering
material in a filter bed with the object of providing for effectual cleansing of the
said bed by upward passage of water through it that is to say the combination of a
thin and finely perforated sheet or thin and finely perforated sheets of practically
non corrodible material with a perforated plate or perforated plates or bars or a
grid or grids substantially as herein before described and illustrated in Figures 4, 5,
6, 7 and 8 of the accompanying drawings.
Fifthly. The combination in a filter substantially as hereinbefore described and
illustrated in Figures 4, 5, 6, 7 and 8 of the accompanying drawings of wire gauze
or the equivalent thereof with a finely perforated sheet or finely perforated sheets
of practically non corrodible material.
Sixthly. The combination of a valve or valves arranged and acting substantially
as and for the purpose herein before described with a perforated sheet or perforated
sheets arranged in a filter as hereinbefore described.
Dated the Eighteenth day of August 1894-
W. T. WHITEMAN,
Agent for the Applicant.