Improvements in Apparatus for Use in connection with the Treatment of Sewage and Impure Waters.
Year: 1894

page_text: Date of Application, 3rd Aug., 1894
Complete Specification Left, 4th June, 1895-Accepted, 6th July, 1895
Improvements in Apparatus for Use in connection with the
Treatment of Sewage and Impure 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 a
follows:-
The first part of my invention relates to improvements in the method o
removing "sludge" or "mud" from the bottom of a precipitation tank or the like.
without the necessity of emptying the tank for that purpose, and consists-
Firstly of a suitable flexible sludge delivery conduit or pipe or conduits or
pipes (which I will call the flexible pipe) free to bend or curve as the hereafter
mentioned perforated sludge collecting pipe, to which the said flexible pipe is
connected, is moved up or down the precipitation tank; in conjunction with
a movable perforated or slotted sludge collecting conduit or pipe or conduits or
pipes or the like (which I will hereafter call the perforated pipe), the said
flexible pipe being arranged as hereafter described and being also connected to
or with a receptacle receiver or the like for the sludge :
Secondly, of a continuously slotted pipe or conduit or pipes or conduits or its
equivalent, which I will call the slotted pipe, to which the aforesaid movable
perforated sludge collecting pipe is connected through the said slot or opening.
and through which said slotted pipe the sludge is removed, the said slot or
opening being provided with a movable cover or covers so that liquid can only
or practically only pass into the said slotted pipe by means of the said
perforated pipe; the sludge is delivered from the said slotted pipe to any
convenient or required spot.
Thirdly, of a precipitation tank having a false bottom the said false bottom
being arranged so that it lays or rests upon the real bottom when the tank is
working but can be raised by a float or floats or by other means to the top of
the tank when required, carrying the sludge with it, the sludge can then be
run off or pumped from the said false bottom by means of a pipe or otherwise,
with or without previous draining; in order to retain the sludge on the false
bottom provide the said false bottom with sides or edges if necessary, the
top of which sides or edges should be above the level of the water in the tank
When I move
when the sludge is being removed from the said false bottom.
a false bottom by means of a Boat or floats I preferably arrange so that when
I wish to sink the false bottom 1 can let water into the float or floats and
when I wish to raise the false buttom I can withdraw the water from the said
float or floats by pumping or otherwise, the place of the water in the float or
floats being preferably taken by air. Instead of constructing a false bottom
which is raised, as before described, I sometimes hinge or pivot the said false
bottom or its equivalent in any suitable manner or manners to the bottom or
sides, or their equivalent, of the precipitation tank, so that the said falsc
bottom can be floated or otherwise raised so that it assumes such a slanting or
upright position that the sludge shall then run or fall down the said false

page_text: bottom to a position from whence it can be readily and easily removed or
withdrawn by a suitably arranged pipe or pipes or in other convenient manner.
I sometimes supplement the running or falling motion of the sludge down the
said false bottom when slanting, by means of a roller or scraper or rollers or
scrapers or the like suitably moved or caused to move over the whole or part
of the false bottom, and I sometimes provide the said false bottom with a ledge
or projection at the pivot or hinged end thereof, which said ledge or projection
is also hinged or pivoted and is arranged that it can be raised when required
so as to retain the sludge at one point, the said ledge or projection is lowered
after the sludge has been removed from the tank. As a modification I some-
times arrange to lower one or more false bottoms or projecting ledges suitably
placed in and hinged or pivoted to the precipitation tank, the act of lowering
the aforesaid one or more false bottoms or projecting ledges causes the sludge
collected thereon to fall to the bottom of the tank from whence it can be
easily removed as before described.
I may use more than one false bottom or the like arrangement before
enumerated in or for a precipitation tank, and I may arrange the aforesaid
false bottom or bottoms or the like arrangement so that they cover a part or
parts only of the bottom of the precipitation tank, and I may vary the details
of arrangement of a false bottom or bottoms or the like, and I may apply the
aforesaid arrangement or arrangements to a rectangular Hat bottomed to a round
conical bottomed or to other shaped tank, and may form a gutter or depression or
gutters or depressions at any suitable part of the tank if necessary.
And fourthly, of a perforated sludge collecting pipe or conduit having the sludge
conducting pipe therefrom attached thereto at or about the longitudinal centre
or having a sludge conducting pipe attached at or at about the two ends of the
said perforated sludge collecting pipe or having more than two sludge conducting
pipes attached at about equal distances apart along the said perforated sludge
collecting pipe; by this means the said perforated sludge pipe can be employed
of very much less How capacity than that which must be used when the sludge
conducting pipe is attached at or near one of the ends thereof as has been
heretofore done.
In removing the sludge from the tank according to the first and second heads of
this part of my invention the same is collected by the aforesaid movable perforated
sludge pipe, carried through the aforesaid flexible pipe or through the aforesaid
slotted pipe, and thence delivered by a further pipe or conduit or pipes or conduits
or the like if necessary to any convenient spot; the sludge being withdrawn from
the tank by the pressure of water in the tank, by pumping, or by any other
suitable means. support the flexible pipe, by means of a float or floats or in
other suitable manner, when necessary. The flexible pipe is preferably a stout
coil of wire covered with sufficiently waterproof material.
Referring to the first head of this part of my invention I connect one end of the
aforesaid Hexible pipe to the aforesaid perforated sludge pipe preferably at or
about the end thereof and preferably by means of a swivel or movable joint, (the
said perforated sludge pipe I will presume reaches across the width of the bottom
of the precipitation tank and is movable up and down the length thereof) and I
connect the other end of the flexible pipe. preferably also by means of a swivel or
movable joint, with an exit pipe or conduit, which will call the exit pipe, the
point of connection between the said flexible pipe and the said exit pipe being
preferably as far as possible from the point of connection between the said flexible
pipe and the said perforated pipe; the said points of connection being also in or
about in a plane running through the centre of the tank and parallel with the
length of the said perforated pipe. This method is especially suitable to a large
square or oblong and comparatively shallow tank, for instance a tank fifty feet
long by thirty feet wide and six feet deep, or larger. Or I connect one end of the
flexible pipe preferably by a swivel or movable joint to the said perforated pipe
and preferably at the top part or side thereof and I connect the other end of the

page_text: said flexible pipe to or with an exit pipe placed at or about an end of the tank
which is parallel with the said perforated pipe, the points of connections of the
flexible pipe are preferably in a plane running through the centre of the tank at
right angles with the length of the perforated pipe, this method is applicable to
smaller tanks than the method before described under the first head. In both the
aforesaid methods I prefer to place the point of connection between the flexible
pipe and the perforated pipe as near the perforated pipe as suitable and the point
of connection between the flexible pipe and the exit pipe about eighteen inches or
two feet below the water level of the tank. The exit pipe I provide with a valve
of a suitable kind.
I support the flexible pipe by a float or floats or in other manner when the
length of the said pipe is such as would otherwise cause it to have a tendency to
bend too sharply at any point and thus close or partly close the aperture in the
pipe and when the flexible pipe would otherwise drag on the tank bottom, when I
employ floats for the purpose 1 preferably make them in the form of a drum or
cylinder having in it an orifice through which the flexible pipe passes the said
drum being in halves which are bolted or otherwise fastened together, by this
means a float can at any time be easily put on or taken off from the flexible pipe.
The length of the flexible pipe is such that it will allow the perforated pipe to be
moved up and down the whole distance required to be cleaned of the tank.
Referring to the second heading of this part of my invention I provide a suitable
slotted pipe or conduit placed in the precipitation tank at any suitable position and
parallel or about parallel with the travel of the perforated pipe and of a sufficient
length to allow the perforated pipe to travel its required distance, the said
perforated pipe being connected to or with the said slotted pipe through the slot
therein which said slot is preferably at the top part or side of the slotted pipe; in
order to prevent other liquid than the sludge passing into the slotted pipe I arrange
to cover that part of the slotted pipe which is not covered by the connection from
the perforated pipe, with a movable covering or coverings so arranged that the
part just passed over by the perforated pipe connection shall be immediately closed
while the covering or coverings in front of the said perforated pipe connection can
be readily moved forward pushed aside or otherwise suitably removed by the
forward motion of the perforated pipe: the perforated pipe may be connected with
the slotted pipe direct or by a rigid extension thereof or therefrom or by a flexible
or jointed extension. As an example of carrying this into effect I attach to each
side of the connection between the perforated pipe and the slotted pipe the ends of
a strip of flexible and sufficiently waterproof material of a length more than double
that of the slot in the slotted pipe, the said flexible strip thus forming with the said
connection an endless band, the said strip is sufficiently wide to cover the slot in
the slotted pipe and passes round a roller or rollers at each termination of the said
slot in the slotted pipe; that part or half of the said strip which is nearer the
slotted pipe lays over the said slot sealing it up and is kept in its required position
by the pressure of the water by its own weight by guide rollers or by other suitable
means, thus as the perforated pipe is moved along the said strip moves too; the
details of the application of this strip may be varied.
The second part of my invention relates to improved means or methods of
moving the perforated sludge collecting pipe or conduit up and down the tank.
The first head of this part of my invention consists in staying or stinging the
said perforated pipe, at its required position of about an inch or less above the
bottom of the tank, from a support or supports placed above the water level of
the tank and having attached wheels or runners which travel on rails or on
other suitable surface placed upon or formed from the wall or walls of the
precipition tank or at other suitable position, the said support or supports and the
perforated pipe are moved along in any convenient manner.
The second head of this second part of my invention consists in driving or
rotating the wheel or wheels which support or carry the perforated pipe, and by
this means I give the required backward or forward motion to the said perforated.

page_text: pipe, the motive power is preferably manual and the operator may stand upon a
platform attached to or connected with the said wheel or wheels.
The third head of this second part of my invention consists in moving the
perforated sludge collecting pipe up and down the precipitation tank by means of a
suitable lazy-tongs arrangement two opposite hinged points of which are connected
together, directly or indirectly, in such manner that they may be thereby brought
together and forced apart thus moving up or down the tank the perforated sludge
collecting pipe which is attached to one end of the said lazy tongs arrangement,
the other end of the said lazy tongs arrangement being suitably attached to the
bottom or sides, or their equivalent, of the said tank. I sometimes make one or
both of the hinged or pivoted parts of the lazy tongs arrangement hollow and
withdraw the sludge therethrough from the said perforated sludge collecting
pipe.
The fourth head of this second part of my invention consists of one or more
guide rollers or wheels the axle or hub of which is at or about at right angles to
the length of the perforated sludge collecting pipe to which it or they are attached
or connected, the said one or more guide rollers or wheels are employed for the
purpose of keeping the said perforated sludge pipe from skewing across the
precipitation tank in which it is placed and the said guide roller or rollers are
adapted so as to engage if necessary with or against the sides of the rails or
the sides of the walls of the said tank or with or against other suitable part
of the tank. I sometimes provide these said guide roller or rollers or wheel or
wheels with springs or buffers & I sometimes also provide the wheels on which the
said perforated sludge pipe runs with springs or buffers.
The third part of my invention relates to improvements in filtering apparatus
and in filter beds.
The first head of this part of my invention relates to improvements in the
perforated false bottom of a filtering apparatus adapted to clean the filtering
material by a reversed or upward flow of water, and consists of a strong plate, for
instance a cast iron plate, having in it the required number and arrangement of
holes or perforations, which are of a considerable size e.g. about three eights of an
inch in diameter, into these large boles I insert or 1 attach, in a practically water-
tight manner, plugs or the like of practically non-corroding material these plugs
having through them a small hole or holes of about one eight to one twentieth of
an inch in diameter, these said holes may be formed in the said plugs either before
or after their insertion into or attachment with the before mentioned large holes ;
I manufacture the said plugs of lead or of copper or of aluminium or of delta
metal or other alloy or of india-rubber or of vulcanite or of suitable wood or of
cork or of other similarly suitable material or materials. I may fix the said plugs
by casting them into the holes in which case the small holes through the plug may
also be formed at the same time by means of a core or the like or I may attach
the said plugs by screwing them into the said large holes or by driving or forcing
them in with or without the aid of a cementing or the like material or I may
cement them in or attach in other suitable manner. When I employ a soft india-
rubber plug or a cork plug I form the small hole therein of a firmly inserted tube
of metal or of other material and when I use a wooden plug I prefer to char the
sides of the small hole therethrough or I sometimes insert therein a tube of metal
or other suitable material, and when I drive or force a plug into the said large
boles I prefer to first insert into the small hole through the said plug a closely
fitting but easily withdrawn suitable piece of wire or the like to keep the said
small hole from becoming closed. Or I sometimes drill or form the small holes
before spoken of, in the iron false bottom itself of the filtering apparatus, and coat
the sides of the said small holes with a suitable metal or composition which will
prevent the said small holes from becoming choked by rusting or corroding;
I sometimes cast or form large holes in the said iron false bottom but which said
large holes are not cast or formed entirely through the said false bottom, by this
means I only require to drill or form the said small holes through a less distance

page_text: of metal than I otherwise should. I sometimes also place the said small holes
through the said false bottom of the filtering apparatus at a slant instead of at
right angles to the said false bottom and I sometimes arrange the slant of the said
small holes so as to produce a rotating or the like motion of the filtering material
when the same is being cleaned by the upward flow of water.
The first head of the third part of my invention consists further of improvements
in the shape of the upper surface of the perforated false bottom of a filtering
apparatus such as before described whereby freer drainage away of the filtered
water from the bottom part of the filter bed is obtained. I form the said upper
surface in a series of narrow but deep gutters placed closely together each gutter
to be effective must lead to one or the more of the perforations in the said false
bottom. I also preferably form a recessed collecting conduit around the edges of
the perforations in the said false bottom; I place above the said indented false
bottom a layer of coarse filtering material preferably of such a size that the
particles of the said coarse material shall not become inserted or fall into the said
gutters in the said perforated false bottoni; I sometimes place a sheet or sheets of
practically non-corroding perforated or reticulated material such as copper wire
gauze upon the said false bottom. I sometimes use a suitably perforated pipe or
pipes as an extra aid in the washing of the filtering material or to reach portions
thereof which are not reached by the upward flow from the perforated false
bottom.
The second head of this third part of my invention consists of improvements
relating to the washing or cleansing of the top fine layer of oxidizing or nitrifying
or the like filter beds and of improvements relating to the supplying of the water
thereto. provide the said filter bed with a suitably perforated pipe or pipes,
preferably of galvanised iron, which said pipe or pipes reach across the filter bed
and are arranged to be moved up and down or around the same, the said perforated
pipe or pipes is or are placed at a suitable depth or depths down in the filtering
material and is or are connected with a supply of suitable water in such a way that
the said water issues from the said perforated pipe or pipes in jets with sufficient
force to scour or wash the aforesaid fine top layer of the filter bed, the dirty water
rising to the top of the filter bed and being drawn away therefrom by suitable
means. The said perforated pipe or pipes are moved up or down or around in the
filter bed during the aforesaid washing or scouring operation, during which I prefer
to have an upward flow of water through the bed obtained from other filter or
filters which are working downwards. I sometimes arrange that the same
perforated pipe or pipes which are used as aforesaid for scouring or washing the
top fine layer of the said filter bed shall be also used for spreading or showering
upon or over the filter bed the water which is to be filtered, for this purpose I
provide or arrange means by which the said perforated pipe or pipes can be raised
up to the required height and also if necessary moved up and down or around the
filter bed; it will be evident that when perforated pipes are arranged for spreading
or showering upon a filter bed the water to be filtered I may arrange to lower them
so that they may also be used for washing or scouring the filter bed. 1 sometimes
place spikes or the like on the aforesaid perforated pipe or pipes used for scouring
or washing a filter bed and provide means whereby the said spiked perforated pipe
or pipes may be revolved when used for scouring a filter bed. I sometimes omit
the perforations and employ a revolving movable spiked pipe or the like for
loosening a sand during the ordinary upward washing of the filter bed.
The third head of this third part of my invention relates to arrangements in
connection with the continuous aerating of filter beds similar for instance to that
described in my Specification No. 18216 of A.D. 1892, and cousists of the
forination of a water seal at the exit of the filtered water from the filter bed, by
this means I am enabled to utilise the water collecting pipes at the bottom of the
filter bed as air spreading pipes, connecting the same with the air (or with a supply
of oxygen or other suitable gas) so as to obtain either an up or down draught of
air without the great risk that the air will either be sucked in or blown out through

page_text: the filtered water exit instead of through the other series of air pipes arranged at
a higher level for that purpose.
Dated this First day of August 1894.
F. PULLEN CANDY.
Improvements in Apparatus for Use in connection with the
Treatment of Sewage and Impure Waters.
I FRANK PULLEN CANDY of No. 56 Nightingale Lane Balham London 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 :-
The first part of my invention relates to the removal of "sludge" from the
bottom of a precipitation tank or the like without necessity for emptying the
tank for that purpose.
The said first part of my invention consists first of a suitable flexible sludge
delivery conduit or pipe or conduits or pipes which I will call the flexible pipe
in conjunction with a movable perforated or slotted sludge collecting conduit or
pipe or sludge collector the said flexible pipe being arranged as hereinafter
described and being in communication with the sludge collector and with a
receptacle or the like to which the sludge is delivered.
The said first part of my invention consists secondly, of a precipitation tank
having a false bottom the said false bottom being arranged so that it lays or
rests upon the real bottom when the tank is working but can be raised by a
float or floats or by chains and a windlass or by other means to the top of the
tank when required, carrying the sludge with it. The sludge can then be run off
or pumped from the said false bottom by means of a pipe or otherwise, with or
without previous draining. In order to retain the sludge on the false bottom
it may be provided with sides or raised edges the tops of which should be above
the level of the water in the tank when the sludge is being removed from the
said false bottom. When I move a false bottom by means of a float or floats I
preferably arrange so that when I wish to sink the false bottom I can let water
into the Hoat or floats and when I wish to raise the false bottom I can withdraw
the water from the said float or floats by pumping or otherwise, the place of the
water in the float or floats being preferably taken by air. The said float or floats
may consist of an air tight compartment or air tight compartiments formed at the
lower part of or below the false bottom or at the sides thereof.
Instead of providing for raising a false bottom as before described, I sometimes
hinge or pivot the said false bottom or its equivalent in any suitable manner or
manners to the bottom or sides, or their equivalent, of the precipitation tank, so
that the said false bottom can be floated or otherwise raised so that it assumes
such a slanting or upright position that the sludge shall then run or fall down the
said false bottom to a position from whence it can be readily and easily removed
or withdrawn by a suitably arranged pipe or pipes or in other convenient manner.
I sometimes supplement the running or falling motion of the sludge down the said
false bottom when slanting, by means of a roller or scraper or rollers or scrapers or
the like suitably moved or caused to move over the whole or part of the false
bottom and sometimes provide the said false bottom with a ledge or projection
at the pivot or hinged end thereof which said ledge or projection is also hinged or
pivoted and is so arranged that it can be raised when required so as to retain
the sludge at one point. The said ledge or projection is lowered after the sludge
has been removed from the tank. As a modification I sometimes arrange to
Jower one or more false bottoms or projecting ledges suitably placed in and hinged

page_text: or pivoted to the precipitation tank. The act of lowering the atoresal one
or more false bottoms or projecting ledges causes the sludge collected thereon
to fall to the bottom of the tank from when it can be easily removed as before
described.
may use more than one false bottom or the like arrangement bofore enumerate l
in or for a precipitation tank and I may arrange the aforesaid false bottom or
bottoms or the like arrangement so that they cover a part or parts only of the
bottom of the precipitation tank, and I may vary the details of arrangement of a
false bottom or bottoms or the like. and I may apply the aforesaid arrangement or
arrangements to a rectangular flat bottomed to a round conical bottomel or to
other shaped tank and may form a gutter or depression or gutters or depressions at
any suitable part of the tank if necessary.
Tanks having false bottoms arranged therein and hinged or pivoted thereto as
bereinbefore described are illustrated in Figures 1, 2, 3, 4, 5, 6, 7, 8 and 9 of the
accompanying drawings in all of which figures the tanks are marked a the
false bottoms are marked the hinges by which the false bottoms are connected to
the tanks are marked and the pipes for withdrawal of sludge from the tanks are
marked c.
Figure illustrates in vertical section a rectangular tank in which a false
bottom provided with raised sides or edges 62 is so arranged as to be capable of
being raised as indicated in broken lines in order to cause the sludge which has
been deposited on it to collect and be confined between it and the portion of
the tank near its hinged cnd whence the said sludge passes or is removed as
required by means of the pipe e which in the arrangement illustrated in the
said figure is perforated on its under side to admit of inflow of the sludge.
Figure 2 is a like view of a tank furnished with wo false bottoms or a false
bottom formed in two parts.
Figure 3 is a like view of a tank furnished with two false bottoms and having a
gutter or depression a formed therein for the sludge to pass into when the false
bottoms are raised.
Figure 4 is a like view of a tank furnished with a false bottom having hinged to
it a flap forming a ledge or projection which flap being brought to the
position indicated in broken lines when the floor is raised and retained in that
position by any suitable means admits of the said floor being lowered without
liberation of the sludge.
Figure 5 is a like view of a tank furnished with a false bottom formed in two
parts to the upper sides of which at or near their hinged edges are hinged
Haps between which the sludge is confined as hereinbefore described with
reference to Figure 4 when the floors are lowered after being raised.
A circular couical bottomed tank having a false bottom hinged thereto and
arranged so that it may be lowered to cause the sludge collected thereon to fall
to the bottom of the tank is illustrated in plan in Figure 6 and in vertical
section in Figure 7. In this arrangement the false bottom is formed in four
parts hinged at b₁ band connected to rods d d having hooks d¹ d¹ formed on
them for engagement with the upper edge of the tank in order to support the
false bottom when in its raised position. The position of the parts of the false
bottom when lowered is indicated by the broken lines in Figure 7.
Figure 8 is a plan and Figure 9 is a vertical section of a rectangular tank
furnished with a false bottom formed in four parts and hinged to the tank at bb.
In using this arrangement the sludge is discharged from the false bottom into the
lowermost part of the tank by raising the several parts of the floor one at a time or
two of the parts on opposite sides may be raised at the same time. The false
bottom may be raised by means of chains connected to it or by other convenient
means.
The said first part of my invention consists thirdly, of a perforated sludge
collecting pipe or conduit having the pipe for conducting sludge therefrom attached
thereto at or about the middle of its length or having a sludge conducting pipe

page_text: attached to it at or near its two ends or having more than two sludge conducting
pipes attached at about equal distances apart. By this means a perforated sludge
pipe can be employed of very much less flow capacity than that which must be
used when the sludge conducting pipe is attached at or near one of the ends thereof
as has been heretofore done.
In removing the sludge from the tank according to the first head of the first part
of my invention the sludge is collected by the aforesaid moveable perforated
sludge pipe and passes through the aforesaid flexible pipe and is thence delivered
by a further pipe or conduit or pipes or conduits or the like if necessary to any
convenient spot the sludge being caused to pass from the tank through the sid
pipes by the pressure of water in the tank or by pumping or by any other suitable
means support the flexible pipe, by means of a float or Hoats or in other suitable
manner, when necessary. The flexible pipes I prefer to use consist of a stout coil
of wire covered with sufficiently waterproof material.
Referring to the first head of the first part of my invention I connect one end of
the aforesaid flexible pipe to the aforesaid perforated sludge pipe preferably at or
near one of its ends and preferably by means of a swivel or movable joint (the
said perforated sludge pipe I will presume reaches across the width of the
bottom of the precipitation tank and is movable up and down the length
thereof) and I connect the other end of the flexible pipe preferably also by
means of a swivel or movable joint with an exit pipe or conduit which I will
call the exit pipe the point of connection between the said flexible pipe and the
said exit pipe being preferably a far as possible from the point of connection
between the said flexible pipe and the said perforated pipe the said points of
connection being also in or about in a plane running through the centre of the
tank and parallel with the length of the said perforated pipe. This method is
especially suitable to a large square or oblong and comparatively shallow tank for
instance a tank fifty feet long by thirty feet wide and six feet deep or longer. Or
I connect one end of the flexible pipe preferably by a swivel or moveable joint to
the said perforated pipe and preferably at the top part or side thereof and I
connect the other end of the said flexible pipe to or with an exit pipe placed
at or about an end of the tank which is parallel with the said perforated pipe.
The points of connection of the flexible pipe are preferably in a plane running
through the centre of the tank at right angles with the length of the perforated
pipe. This method is applicable to smaller tanks than the method beforedescribed
under the first head. In both the aforesaid methods I prefer to place the point of
connection between the flexible pipe and the perforated pipe as near the perforated
pipe as suitable and the point of connection between the flexible pipe and the exit
pipe about eighteen inches or two feet below the water level of the tank. The
exit pipe I provide with a valve of a suitable kind by opening or closing which the
passage of the sludge from the tank may be permitted or prevented.
I support the flexible pipe by a float or floats or by other means when the length
of the said pipe is such as would otherwise cause it to have a tendency to bend
too sharply at any point and thus close or partly close the aperture in the pipe and
when the flexible pipe would otherwise drag on the tank bottom. When I employ
floats for the purpose I preferably make them in the form of a drum or cylinder
having in it an orifice through which the flexible pipe passes the said drum being
in halves which are bolted or otherwise fastened together. By this means a float
can at any time be easily put on or taken off from the flexible pipe. The length
of the flexible pipe is such that it will allow the perforated pipe to be moved up
and down the whole distance required to be cleaned of the tank.
The second part of my invention relates to improved means or methods of moving
the perforated sludge collecting pipe or conduit up and down the tank.
The first head of the said second part of my invention consists in suspending or
slinging the said perforated pipe at its required position of about an inch or less above
the bottom of the tank from a support or supports placed above the water level of
the tank and having attached wheels or runners which travel on rails or on other

page_text: suitable surface placed upon or formed from the wall or walls of the precipitation
tank or at other suitable position. The said support or supports and the perforate
pipe are moved along in any convenient manner.
The second head of the said second part of my invention consists in driving or
rotating the wheel or wheels which support or carry the perforated pipe and by this
means I give the required backward or forward motion to the said perforated pipe.
The motive power is preferably manual and the operator may stand upon a platform
attached to or connected with the said wheel or wheels.
The third head of the said second part of my invention consists in moving the
perforated sludge collecting pipe up and down the precipitation tank by means of a
suitable lazy tongs arrangement two opposite hinged points of which are connected
together directly or indirectly in such manner that they may be thereby brought
together and forced apart thus moving up or down the tank the perforated sludge
collecting pipe which is attached to one end of the said lazy tongs arrangement the
other end of the said lazy tongs arrangement being suitably attached to the bottom
or sides or their equivalent of the said tank I sometimes make one or both of the
hinged or pivoted parts of the lazy tongs arrangement hollow and withdraw the
sludge therethrough from the said perforated sludge collecting pipe.
The fourth head of the said second part of my invention consists of one or more
guide rollers or wheels the axle or hub of which is at or about at right angles to
the length of the perforated sludge collecting pipe to which it or they are attache.l
or connected. The said one or more guide rollers or wheels are employed for the
purpose of keeping the said perforated sludge pipe from skewing across the
precipitation tank in which it is placed and the said guide roller or rollers are
adapted so as to engage if necessary with or against the sides of the rails or the
sides of the walls of the said tank or with or against other suitable part of the tank.
I sometimes provide these said guide roller or rollers or wheel or wheels with
springs or buffers and I sometimes also provide the wheels ou which the said
perforated sludge pipe runs with springs or buffers.
Figure 10 of the accompanying drawings is a plan and Figure 11 is a vertical
longitudinal section (taken on the line XX Figure 10) of a precipitation tank
showing one of the arrangements hereinbefore described of the flexible pipe by
which sludge is conveyed from the travelling perforated sludge collecting pipe to
the sludge outlet of the tank and one of the arrangements herein before described
for preventing skewing of the sludge pipe while being moved over the bottom of
the tank. Referring to the said figures e is the tank. is the travelling perforated
sludge pipe which is suspended from a girder 9 fortning part of a carriage provided
with wheels h h resting on rails ii mounted on the tank walls which carriage is
drawn backwards and forwards in the tank as required by means of au endless
chain connected to a windlass j mounted on one of the end walls of the tank and
passing over a pulley & secured to the opposite wall of the tank. is the flexible
pipe which is connected to the perforated pipe at l' by means of a swivel joint
and to the sludge outlet e of the tank by means of a similar joint. The valve for
controlling the passage of sludge through the sludge outlet is arranged at or near
the point of connection of the flexible pipe with the said outlet. e is the inlet
channel and e is the inlet trough from which the sewage or water to be treated
passes into the passage e' on its way to the tank. is the overflow trough into
which the water after treatment passes on its way from the tank.
guide rollers by which skewing of the sludge pipe is prevented which rollers are
carried by arms m' m' affixed to the pipe and bear against the side walls of
the tank.
mm are the
The third part of my invention relates to improvements in filtering apparatus and
iu filter beds.
The first head of this part of my invention relates to improvements in the
perforated false bottom of a filtering apparatus adapted to clean the filtering
material by a reversed or upward flow of water and consists of a strong plate for
ts

page_text: instance a cast iron plate having in it the required number and arrangement of
holes or perforations which are of a considerable size e.g. about three eighths of atr
inch in diameter. Into these holes I insert or I attach in a practically water tight
mauner plugs or the like of practically non-corroding material these plugs having
through them a small hole or holes of about one eighth to one twentieth of an inch
in diameter which small holes may be formed in the said plugs either before or after
their insertion into or attachment with the before mentioned large holes. I
manufacture the said plugs of lead or of copper or of aluminium or of delta metal or
other alloy or of india rubber or of vulcanite or of suitable wood or of cork or of
other similarly suitable material or materials. I may fix the said plugs by casting
them into the holes in which case the small holes through the plug may also be
formed at the same time by means of a core or the like or I may attach the said
plugs by screwing them into the said large holes or by driving or forcing them in
with or without the aid of a cementing or the like material or I may cement them
in or attach in other suitable manner. When I employ a soft india-rubber plug or
a cork plug I form the small hole therein of a firmly inserted tube of metal or of
other material and when I use a wooden plug I prefer to char the sides of the small
hole there-through. Or I sometimes insert therein a tube of metal or other suitable
material. When I drive or force a plug into the said large hole I prefer to first
insert into the small hole through the said plug a closely fitting but easily
withdrawn suitable piece of wire or the like to keep the said small hole from
becoming closed.
Figure 12 of the accompanying drawings represents in section a portion of the
false bottom of a filtering apparatus in which is inserted a plug having a small hole
formed therein as hereinbefore described. Referring to the said figure is the
false bottom. o is the plug and o' is the small hole in the said plug.
Figure 13 represents a tool suitably formed for use in driving the plugs into the
holes in the false bottom and for preventing closure or contraction of the holes in
the plugs while they are being so driven. When the said tool is to be used the
part pis engaged with the hole o' in the plug and the part y fits in the conical
recess above the said hole.
Or I sometimes drill or form the small holes before spoken of in the iron false
bottom itself of the filtering apparatus and coat the sides of the said small holes
with a suitable metal or composition which will prevent the said small holes from
becoming choked by rusting or corroding. I sometimes cast or form large holes in
the said iron false hottom but which said large holes are not cast or formed entirely
through the said false bottom. By this means I only require to drill or form the
said small holes through a less distance of metal than I otherwise should.
1 sometimes also form the said small holes through the said false bottom of the
filtering apparatus at a slant instead of at right angles to the said false bottom and
I sometimes arrange the slant of the said small holes so as to produce a rotating
or the like motion of the filtering material when the same is being cleaned by the
upward flow of water.
The said first head of the said third part of my invention consists further of
improvements in the shape of the upper surface of the perforated false bottom of a
filtering apparatus such as before described whereby freer drainage away of the
filtered water from the bottom part of the filter bed is obtained. I form the said
upper surface in a series of narrow but deep gutters placed closely together each
of which gutters to be effective must lead to one or more of the perforations in the
said false bottom. I also preferably form a recessed collecting conduit around the
edges of the perforations in the said false bottom. I place above the said indented
false bottom a layer of coarse filtering material preferably of such a size that the
particles of the said coarse material shall not become inserted or fall into the said
gutters in the said perforated false bottom. I sometimes place a sheet or sheets of
practically non-corroding perforated or reticulated material such as copper wire
gauze upon the said false bottom. I sometimes use a suitably perforated pipe or

page_text: pipes as an extra aid in the washing of the filtering material or to reach portions
thereof which are not reached by the upward flow from the perforated false
bottom.
The second head of the said third part of my invention consists of improvements
relating to the washing or cleansing of the top fiue layer of oxidizing or nitrifying
or the like filter beds and of improvements relating to the supplying of the water
thereto. I provide the said filter bed with a suitably perforated pipe or pipes
preferably of galvanised iron which said pipe or pipes reach across the filter bed
and are arranged to be moved up and down or around the same the said perforated
pipe or pipes is or are placed at a suitable depth or depths down in the filtering
material and is or are connected with a supply of suitable water in such a way that
the said water issues from the said perforated pipe or pipes in jets with sufficient
force to scour or wash the aforesaid fine top layer of the filter bed the dirty water
rising to the top of the filter bed and being drawn away therefrom by suitable
means. The said perforated pipe or pipes are moved up or down or around in the
filter bed during the aforesaid washing or scouring operation during which I prefer
to have an upward flow of water through the bed obtained from other filter or
filters which are working downwards.
Figure 14 is a vertical section of the upper portion of a filter showing the
arrangement therein of a perforated pipe so mounted that the horizontal portion
thereof in which the perforations are formed is embedded in the layer of fiue
material which constitutes the uppermost stratum of the filter bed and is capable
of being moved around therein. In the said figure the filter bed is marked ŕ and
the perforated pipe s. t is a pipe by which water is conveyed to the perforated
pipes which pipe t is so connected to the pipe s that the latter can be moved as
required without motion of the pipe t. The arrangement illustrated in Figure 10
of the drawings accompanying my Specification No. 8671 of 1894 is suitable
for giving the required motion to the pipe s or any other convenient arrangement
of mechanisin may be used for the purpose.
I sometimes arrange that the same perforated pipe or pipes which are used
as aforesaid for scouring or washing the top fine layer of the said filter bed shall
be also used for spreading or showering upon or over the filter bed the water which
is to be filtered. For this purpose I provide or arrange means by which the said
perforated pipe or pipes can be raised up to the required height and also if
necessary moved up and down or around the filter bed. It will be evident that
when perforated pipes are arranged for spreading or showering upon a filter bed
the water to be filtered I may arrange to lower them so that they may also be
used for washing or scouring the filter bed. I sometimes place spikes or the like
on the aforesaid perforated pipe or pipes used for scouring or washing a filter bed
and provide means whereby the said spiked perforated pipe or pipes may be
revolved when used for scouring a filter bed. I sometimes omit the perforations
and employ a revolving movable spiked pipe or the like for loosening the sand
during the ordinary upward washing of a filter bed.
The third head of the said third part of my invention relates to arrangements in
connection with the continuous aërating of filter beds similar for instance to that
described in my Specification No. 18216 of A.D. 1892 and consists in the formation
of a water seal at the exit of the filtered water from the filter bed. By this means
I am enabled to utilise the water collecting pipes at the bottom of the filter bed as
air spreading pipes connecting the same with the air (or with a supply of oxygen
or other suitable gas) so as to obtain either an up or down draught of air without
the great risk that the air will either be sucked in or blown out through the filtered
water exit instead of through the other series of air pipes arranged at a higher
level for that purpose.
Figure 15 of the accompanying drawings is a section of a portion of the lower
part of a filter showing the water outlet with a water seal applied thereto as
herein before described being a portion of the side wall of the filter and va
portion of the bottom thereof. to is the collecting channel and is the water seal.

page_text: arranged in the outlet for the filtered water which water seal may consist of an
ordinary stoneware "trap."
said
Having now particularly described and ascertained the nature of my
invention and in what manner the same is to be performed I declare that I
claim
First. The arrangement in a precipitation tank of a false bottom for receiving
the precipitate the said false bottom being capable of being raised for the purpose
of removing the precipitate therefrom substantially as hereinbefore described.
Secondly. The arrangement in a precipitation tank of a false bottom or false
bottoms capable of being raised in such a manner as to cause precipitate deposited
thereon to pass to and be confined between a portion thereof and the tank walls or
between portions of the said false bottoms substantially as described.
Thirdly. The combination of a flap or flaps with a precipitation tank floor
capable of being raised substantially as and for the purpose hereinbefore described
with reference to Figures 4 and 5 of the accompanying drawings.
Fourthly. The combination with a precipitation tank of a false bottom so
formed and arranged that the precipitate deposited thereon may be discharged
therefrom into the portion of the tank below it substantially as herein before
described and illustrated in Figures 6 and 7 of the accompanying drawings.
Fifthly. The combination of a float or buoy substantially as and for the purpose
hereinbefore described with a flexible pipe arranged to conduct sludge from a
travelling sludge collector mounted in a precipitation tank.
Sixthly. The means hereinbefore described for conducting sludge from a
travelling sludge collector mounted in a precipitation tank that is to say a flexible
pipe connected with the said sludge collector by means of a swivel joint and
arranged to deliver the sludge as required.
Seventhly. The means hereinbefore described for conducting sludge from a
travelling sludge collector mounted in a precipitation tank to a fixed outlet that is
to say a flexible pipe connected with the said sludge collector and also connected
by means of a swivel joint with a fixed outlet.
Eighthly. The arrangements hereinbefore described for supporting and moving
a sludge collector in a precipitation tank which arrangements consist essentially of
a carriage supported above the tank bottom on wheels from which carriage the
sludge collector is suspended and through the medium of which carriage the said
sludge collector may be moved as required over the surface of the tank bottom.
Ninthly. The combination with a wheel carriage for supporting a movable
sludge collector in a precipitation tank as hereinbefore described of arrangements
admitting of the application or communication of power to the wheels of the said
carriage for the purpose of imparting motion thereto as required in order to move
the said sludge collector over the bottom of the tank.
Tenthly. The combination with a sludge collector designed for application to or
arrangement in a precipitation tank substantially as herein before described of
guides arranged and capable of acting substantially as herein before described and
illustrated at m m¹ in Figures 10 and 11 of the accompanying drawings.
Eleventhly. The arrangement of plugs of incorrodible material or material but
little liable to corrosion in holes in the false bottom of filtering apparatus designed
to be cleaned by upward flow of water the said plugs being pierced either before
or after insertion in the said holes substantially as herein before described.
Twelfthly. The combination of tubes of incorrodible or practically incorrodible
material with plugs of india rubber or cork or other readily compressible material
substantially as herein before described and the arrangement of such plugs in holes
in the false bottom of filtering apparatus as and for the purpose herein before
described.
Thirteenthly. The improvement herein before described in filters having
provision for the cleansing of the bed of filtering medium by upward flow of water
therethrough which consists in so forming the passages through which the upward

page_text: currents of water pass to the said bed that a rotating or swirling movement of the
filtering medium is produced by the entering water.
Fourteenthly. The arrangement of perforated water conveying pipes in the
layer of fine material in the bed of a filter so that the said pipes may be moved up
and down or around in the said layer substantially as and for the purpose herein-
before described.
Fifteenthly. The combination of a water seal with the water outlet of an
aërating filter substantially as and for the purpose hereinbefore described.
Dated the First day of June 1895.
F. PULLEN CANDY.