An Automatic or Self-cleansing Filter.
Year: 1895

page_text: Date of Application, 17th Oct., 1895
Con plete Specification Left, 16th July, 1896-Accepted, 5th Sept,
1896
An Automatic or Self-cleansing Filter.
I, JAMES WILSON, of '39 ''Borrodaile Road, Wandsworth in the -County of
Surrey, Plumber, do hereby declare the nature of this invention to 'be as
follows:-
My invention has for its principal-object the rapid filtration of water to 'fit it
for use in manufactures but it may be used under other circumstances more
especially where rapid filtration is required.
The filter bed may be of any suitable material "I prefer very finely granulated
coke prepared by grinding; it is spread in a layer several inches thick on a plate
of perforated metal or upon wire cloth. Over the filter bed another por forated
plate is fixed.
१
The water to be filtered 18 drawn from a cistern, it is distributed uniformly-over
the surface of the upper perforated plate, it passes through the filter and so 'to %
storage tank
An approximately umform head is maintained in the cistern, it is supplied
through two pipes, one of which is constantly running whilst the other is fitted
with a ball cock which shuts when the water is at the proper working level.
When the filter is clean it is able to carry off the whole supply but as it becomes
choked the water accumulates above the filter 'bed.
An automatic siphon discharges the water which thus accumulates, as soon as it
reaches a certain depth, for then the filter bed requires to be cleansed. The
cleansing is effected by reversing the direction of the flow through the 'filter bed and
this reversal is brought about by the action of the above mentioned siphon. The
water delivered by the siphon fills and overflows a box or receptacle in which is a
float and the float in rising by suitable connections closes two valves, namely a
valve by which the water passes from the cistern on its way to the filter bed and
a valve which the water, alter filtration, passes on its way to the storage tank. On
the closing of the outlet from the cistern the cistern fills up rapidly, more especially
as its mouth is narrow and then another siphon which this cistern contains comes
into action. By this second siphon the cistern is rapidly discharged down a pipe
which leads the water into the closed space beneath the filter 'bed. This water
forces its way upwards through the filter bed carrying the mud or deposit before
it. The foul water passes off by the first mentioned siphon, which is still in action,
and by its all-drained away. When the flow from the siphons ceases the before
mentioned box or receptacle soon empties through a small open outlet and then'the'
float ialling the two valves which it controls-open.
.
This takes place whilst the space beneath the filter is full of unfiltered water
which should not be allowed to mix with that which has been filtered. To prevent
this the following meaus are employed; a second box or receptacle also- containing
alfloat is arrangeil alongside the 'hrst box and is filled by the overflow from it.
The floatin-rising lifts a reliet valve and holds it open so that any water then
passing down the filtered water-channel is diverted and is run off to waste. "This
second box or receptacle does not empty so rapidly as the first, the outlet *from it
being smaller. Consequently the opening of the valve for the escape of water
from beneath the filter bed takes place before the relief valve closes and the

page_text: unfiltered water escapes by it. When the valves have all returned to their original
positions the filtration proceeds as before
Dated this 16th day of October 1895.
An Automatic or Self-cleansing Filter.
I JAMES WILSON of 39 Borrodaile Road Wandsworth in the County of Surrey
Plumber 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:-
According to my invention the washing of the filter bed is brought about by an
automatic siphon which discharges the water when it accumulates above the
filter bed.
The water delivered by the automatic siphon raises a float which closes the inlet
and outlet valves by which the water passes on to and from the filter bed and the
automatic siphon also determines the discharge of a measured quantity of water
upwards through the filtering bed to cleanse the filter
The washing water is diawn from a measuring cistern by another automatic
siphou; these of the float causes this automatic siphon to operate, and the water
passes from the cistern through the filtering bed in an upward direction.
There is another float which is raised in the same way as the float previously
mentioned, it controls a valve by which the portion of the washing water which
remains below the filter bed is allowed to escape before filtered water is again
collected.
The floats are contained in troughs or open boxes having inlets and outlets
regulated by slides.
In order that my said invention may be fully understood and readily carried into
effect I will proceed to describe the diawings annexed.
Figures 1 and 2 are elevations of an automatic self cleansing filter in accordance
with my invention. Figure 1 is partly in section.
Figure 3 is a plan.
Figures 4 and 5 are respectively sections on the lines 4-4 and 5-5 in
Figure 1
Figure 6 shows a modification of the valve by which the filtered water
passes and
Figure 7 is a vertical section of the upper part of the apparatus showing a
modification which is made when it is desned to wash the filter with a panel water
thau that which is passed through the filter.
The filter bed a may be of finely granulated gas coke free from dust, it is
contained within a comical or pyramidal casing a', it rests on a bottom plate a³ of
perforated sheet metal or wire cloth and some distance above it there is another
similar plate or wire cloth a³. The perforations in both plates or cloths are
sufficiently fine to retain the filtering material The water to be filtered enters
from a side pocket 6 by the opening into the open though c and passes through
the perforated plate a³ which forms a bottom to this trough. In one method of
using the filter which I will first describe the water descends into the pocket & from
the cisternd which measures the washing water and which is continuously
supplied by a pipe d'. The filtered water passes off by a pipe e and after passing
certain valves is delivered at e¹. For a time the filter is able to carry off the whole
of the water supply but when it becomes somewhat clogged the water accumulates
in the trough c in which there is an automatic siphon of a well known type contained
in a side chamber and consisting of a bell covering an outlet pipe f¹. When the

page_text: 1
water in the trough has sen sufficiently to cover the open end of the pipe fit
causes the siphon to operate and the water is rapidly drawn 'out of the trough until
it is empty, and the lower edge of the bell becomes uncovered. The emptying of
the trough occupies some-little tune and in this interval the washing of the filtering
material takes place, and other changes are brought about.
The water delivered by the siphon is received first into a pocket'g thence it
over flows an adjustable neu g¹ consisting of a plate which can be slidden up and
down the outer side of the open boxes in which are floats ³ h* The water
passes from the pocket g into these boxes and buth floats rise and several valves aic
thereby operated upon The float is connected as shown with thres valves;
d2 and 3 are exil valves by which the water descends from the cistern, and 213
the outlet valve by which the filtered water leaves the filter, all these valves when
the float rises fall to their seats At the time when this takes place the
Cistern dis nearly full, two outlet valves are provided to ensure that it shall be iso,
the lower valve will not deliver the full supply so the water level in the cistein
ises until the upper valve d³ is reached and there remains stationary until 'the
valves close In this cistein there is another automatic siphon and when the
outlet valves are closed the water soon lises in the cistern sufficiently to bring this
siphon into action, more especially as the cistern is contracted at the upper part
Also to render the action more prompt a second supply may be provided controlled
by a ball cock which opens as soon as the water commences to se in the cistern
on the closing of the outlets, such an additional supply will not however in most
cases be needed.
The siphon comes into action before the siphon previously mentioned
censes to operate and discharges the whole contents of the cistein d down the
pipe an escaping from the pipe by the vent tube / The pipe delivers 'the
water under the filter bed, it is distributed by the baffle plate a and it rushestup
through the bed thereby cleansing the same and carrying the mud up through the
perforated plate a³. This goes on until the cistein has been emptied by one
siphon and the trough c by the other.
The water which first descends from the trough fills the pochet y and the
boxes h and then the foul water which has washed the filter bed follows aud
reaching the raised outlet m flows away by it Over the outlet m is a bell m'
constituting another automatic siphon by which the porket gis completely emptied.
The outlet pipe m is telescopie and its mouth together with the adjustable
wen are so set as to draw off the duty water as soon as, it' arrives. When
the flow from the tough ceases the boxes h h empty by the regulated
outlets and ; fist the float ³ falls and opens the valves and d³ and
but the float is slower to descend Now this float ¹ controls a valve n and 'it
holds it open whilst the unfiltered water below the filter bed as discharged by a
passage o which also receives the water which passes out by the apertures 45 and hº.
This water may either be allowed to run to waste or it may be collected and
alter waids hltered.
ว
When the valve a closes filtered water again commences to flow from the exit
at e and hltening-goes on as before...
'
In place of the two valves and n I may employ the double valve shown by
Figure 6. When the valve is down the filtered water passes over it and is
delivered at e, when it is up, being lifted by the float hit allows the water from
beneath the filter bed to pass away by the pipe o
'
'
When the water to-be filtered is not fit to wash the filter bed, as for example
sewage, then the apparatus is worked, in a somewliat different manneı The
valves d² and d³ are disconnected and are kept constantly, closed and cistern d is no
longer supplied continuously but intermittently through a smalbauxiliary cistern p
(see Figure 7) The water for washing,the filter is supplied by the ball cock pl
hich closes when the cisterns are full." 2 is a.valve which allows water to pass
from the auxiliary into the main cistein, it is connected with a ballsfloat in the
main cistern and closes hen this cistein has received its supply. The valve pis
.

page_text: also connected with a lever which at its other end' is coupled with the float h
in such manner that the use of the float causes the valve p³ to be lifted and the
contents of the auxiliary cistern to be discharged into the main cistern; thus the
siphon is brought into operation and' the contents of both cisterns are discharged
beneath the filter bed.
The sewage or impure water to be filtered enters the pocket b by a valve at s
and this valve being coupled with the float by means of a lever and cord drops
to its seat when the float ses so that this inlet is closed during the washing
operation. is an overflow pipe with which, by way of precaution, the cistern dis
provided, a valve is provided to close it; this valve is lowered to its seat by the
rise of the float h³.
Foi filters of large size I provide two or more filter beds side by side with
washing arrangements common to the pair or series.
Or with a single filter bed wben of large size I may, for the better distribution
of the washing water, divide the space beneath the filter bed into two or more
sections.
It is obvious that the apparatus will if required filter liquids other than water.
Having now particularly, described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claun is:-
1 The combination of a filter bed, means for supplying liquid to be filtered
to the upper side of the filter bed and for withdrawing the filtered liquid' from the
under side thereof, an automatic siphon which withdraws quid from the upper
surface of the filter bed when it ceases to pass through as rapidly as it is supplied
and moans by which the descent of liquid through the said automatic siphon
arrests the supply to the upper surface of the filter bed and the escape from the
under surface thereof aud di ects a flow of liquid upwards through the filter bed.
.
2 The combination of a filter bed, means for supplying liquid to and with-
drawing filtered liquid from the filter bed, means for discharging liquid when it
accumulates above the filter bed; a cistern containing' a measured quantity of
liquid for washing the filter bed, means by which the descent of liquid from above
the filter bed airests the supply of liquid above the filter bed and discharges the
contents of the cisteru upwards through the filter bed:
3. The combination of a filter bed, means for supplying liquid to and with-
drawing filtered liquid from the filter bed, an automatic siphon which discharges
hquid when it accumulates above the filter bed, a cistern containing a measured
quantity of liquid for washing the filter bed, means by which the descent of liquid
through the said automatic siplion arrests the supply of liquid above the filter bed,
and discharges the contents of the cistern upwards through the filter bed.
4. The combination of a filter bed, means for supplying liquid to and with-
diawing filtered liquid from the filter bed, an automatic siphon which discharges
liquid when it accumulates above the filter bed, a cistern containing a measured
quantity of liquid for washing the filter bed, a float raised by the liquid delivered
by the said automatic siphon, valves connected with the float and means by which
the rise of the float effects the discharge of the cistern' upwards through the
filter bed.
5. The combination of a filter bed, means for supplying liquid to and with
drawing filtered liquid from the filter bed, au automatic siphon which discharges
liquid when it accumulates above the filter bed; means by which the descent of
liquid through the said automatic siphon airests the supply of liquid above the
filter bed, and directs a flow of liquid up through the filter bed to wash the same
and a valve controlled by a float raised by the liquid' discharged by the siphon
which allows the washing liquid to escape from below the filter bed and prevents it
from mixing with the filtered water
6. The combination of a filter bed, means for supplying liquid to and with-
diawing filtered liquid from the filter bed, an automatic siphon' which discharges

page_text: liquid when it accumulates above the filter bed, a trough receiving liquid from the
automatic siphon, regulated passages by which the liquid enters and leaves the
trough, and a float in the trough controlling valves which regulate the passage of
the liquid.
JAMES WILSON.