the method of, and in apparatus for, purifying water
Year: 1887

page_text: We AMOS HERBERT HOBSON, Analytical and Consulting Chemist and CHARLES
HENRY ROSHER, Civil Engineer, both of 5 Westminster Chambers, Victoria 'Street
in the City of Westminster do hereby declare the nature of this invention to be as
follows:-
Our Invention relates to improvements in the method of, and in apparatus for,
purifying water; and the invention is principally designed for dealing with large
bodies of water, such as are used in public baths and manufacturing establishments,
but is also partly applicable for purifying water for drinking and potable purposes.
The Invention as applied to cleansing the water of a swimming bath comprises the
treatment of the water by chemical precipitation filtration and aeration carried out by
means of apparatus wherein the filtering medium is kept constantly efficient whilst the
filter is working, as hereafter described.
The filter which operates per ascensum, is constructed of an outer and inner tank or
vessel with a space between them. Within the inner vessel upon a perforated false
bottom covered with asbestos cloth or fibre or other fabric or finely divided substance
rests the bed of filtering medium. The walls of the inner vessel rise some distance
above the filter bed for a purpose hereafter described, and are provided with an
outwardly projecting lip or flange over which the filtered water flows. The unfiltered
water is supplied under the pressure of a sufficient head, to the chamber beneath the
perforated false bottom through a vertical pipe which may pass down centrally through
the filter bed to the space below, and into this pipe a precipitating or clarifying
solution is injected which is intimately mixed with the unfiltered water and forms a
gelatinous precipitate whereby organic matters (such as would be imparted to
the water by the human body or by certain manufacturing operations) in suspension
in the water are precipitated in the chamber beneath the filter bed. The filter is in
this way relieved of some of the mechanical part of the work of filtration and is not
liable to become clogged. It consequently has chiefly the chemical purifying action
to perform and in order to maintain the filtering medium for a much longer time in an

page_text: efficient condition air is injected or otherwise introduced along with the unfiltered
water and is carried by it through the filtering medium, thereby continually restoring
to the latter its chief purifying agent, which soon becomes exhausted in cases where
the filtering medium is constantly kept covered by water. The water before being
admitted to the filter is passed through a strainer to remove solid matters, the strainer
being arranged so as to be readily removed and cleansed when required, and the water
on its way to the filter is caused to work a turbine or other motor which drives a fan
or blowing apparatus. The water after passing through the filter collects in the space
above it, the weight of this supernatant water serving to prevent the disturbance of
the filtering medium by the water in its upward passage. The excess of filtered
water overflows the lip or flange at the top of the inner vessel and falls in the annular
spaco around it, in the form of a thin sheet or cascade which may be broken up into
small particles by dashers or otherwise. The water in falling, dissolves or absorbs air
which is forced in through a perforated pipe at the bottom of the annular space by the
fan or blower above mentioned and the ascending current of air meeting the falling
stream of water which thus becomes thoroughly acrated, the purified and aerated
water collecting at the bottom of the annular space whence it is drawn off for use.
In cases where there is not a sufficient head of water to drive the turbine, the fan or
blower would be worked by other means.
Suitable pipe connections are provided for enabling the precipitation chamber to be
washed out and the passage of the water to be reversed through the filter, whenever it
is necessary to cleanse the same.
Filters for drinking and potable water, would be constructed and operate in a
similar way, so far as the filtration and aeration of the water is concerned, the
precipitation and the forcible injection of air being however omitted, the water
being aerated merely by dripping in a divided condition through the annular space
between the inner and outer vessels to which the air has free access. If the water
supply to the filter be constant as where large quantities of filtered water are required,
the inlet may be connected directly to the bottom of the chamber beneath the filtering
medium, and the filtered water be drawn off from the annular space to the
reservoir for filtered water which, in that case, would not be contained in the filter
itself.
Domestic filters would be similarly constructed, except that they would have a
reservoir for unfiltered water above communicating by a pipe leading down through
the filtering medium to the chamber beneath. Below the bottom of this chamber and
beneath the annular space which surrounds said chamber, is a reservoir for filtered
water and the inner vessel containing the filtering medium is in this case, supported
by being connected to the sides of the water vessel by means of a trough like
bottom to the annular space, said trough being perforated and serving to break up
the water falling in the annular space and allow it to drip into the reservoir for filtered
water, below.

page_text: COMPLETE SPECIFICATION.
Improvements in the Method of and in Apparatus for Purifying
Water.
We, AMOS HERBERT HOBSON, Analytical and Consulting Chemist, and CHARLES
HENRY ROSHER, Civil Engineer, both of 5, Westminster Chambers, Victoria Street, in
the City of Westminster, "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:
Our invention relates to improvements in the method of, and in apparatus
for, purifying water; and the invention is principally designed for dealing with
large bodies of water such as are used in public baths and manufacturing
establishments but is also partly applicable for purifying water for drinking and
potable purposes.
The Invention, as applied to cleansing the water of a swimming bath, comprises the
treatment of the water by chemical precipitation, filtration, and aeration, carried out
by means of apparatus wherein the filtering medium is kept constantly efficient whilst
the filter is working, as hereafter described.
Reference is to be had to the accompanying drawings forming part of this
specification wherein figure 1 is a vertical section of the filter shewing the connections
with the swimming bath etc. Figures 2 and 3 are sections of an intercepting trap
interposed between the bath and filter. Figures 4 and 5 are a vertical section and
part sectional plan of a modified form of filter; and figures 6 and 7 are vertical and
horizontal sections of a filter for domestic purposes. The same letters of reference
indicate the same parts in all the figures.
Referring to figures 1 to 3, the filter A, which operates per ascensum, is contained
within a double tank B, C; with intervening space D. Within the inner tank B
upon a perforated false bottom resting on angle iron ribs a and covered with
asbestos cloth or fibre or other fabric or finely divided substance, rests the bed A of
filtering medium.
The walls of the inner vessel B rise some distance above the filter bed for a purpose
hereafter described, and are provided with an outwardly projecting lip or flange b over
which the filtered water flows and falls into the space D. The unfiltered water is supplied
under the pressure of a sufficient head to the chamber E beneath the filter bed through a
vertical pipe F which preferably passes down centrally through the filter bed to tho
chamber E so as to be available also as a central support for the filter bed. This
pipe F terminates within the chamber E in a head f with perforated walls, by which
the water is distributed uniformly through the chamber E. The pipe F connects with
the draw off pipe G and overflow pipe H communicating with the tank I of the
swimming bath and controlled by cocks h i.
Into this pipe F a precipitating or clarifying solution is injected from a tank K
above, through a pipe & terminating in a nozzle within the pipe H so that the solution
will be intimately mixed with the unfiltered water and form a gelatinous precipitate

page_text: whereby organic or other matters in suspension in the water are precipitated in the
chamber E beneath the filter bed. The filter is in this way relieved of some of the
mechanical part of the work of filtration and is not liable to become clogged. It
consequently has chiefly the chemical purifying action to perform, and in order to
maintain the filtering medium for a much longer time in an efficient condition air is
injected or otherwise introduced along with the unfiltered water and is carried by it
through the filtering medium, thereby continually restoring to the latter its chief
purifying agent, which soon becomes exhausted in cases where the filtering medium
is constantly kept covered by water. For this purpose an air pipe L is led into
the pipe F and terminates within the latter in a nozzle through which air is
inhaled by the inductive action of the water or blown by a fan worked by a turbine
or other motor. Where a sufficient force or head of water can be obtained; the
water, on its way to the filter, may be made to work a turbine or other motor for
driving the blowing apparatus.
The water before being mixed with the precipitating solution is passed through an
intercepting trap M. containing a strainer m to remove solid matters, the strainer being
arranged as shown in figures 2 and 3, so as to be readily removed and cleansed when
required. For this purpose, the wire gauze strainer m is placed in a vertical position
at the lower part of the trap M which it divides transversely, and it is carried by
a frame m forming at the upper part a partition or curtain interposed between the
inlet and outlet, the said frame being fitted in vertical guides at the sides of the
trap from which it is readily removable. The trap is provided at the bottom with
an outlet pipe on the inlet side of the strainer for cleaning out the deposit.
The water after passing through the filter, collects in the space above the filter bed,
the weight of this supernatant water serving to prevent the disturbance of the filtering
medium by the water in its upward passage. The excess of filtered water overflows
the lip or flange and falls in the annular space D in the form of a thin sheet or
cascade which may be broken up into small particles. The water in filling comes
in contact with, and dissolves or absorbs, air which may be renewed by
forcing air in through a perforated pipe N at the bottom of the annular space D by
the fan or blower above mentioned, the ascending current of air meeting the falling-
stream of water which thus becomes thoroughly acrated. This additional aeration
is not however essential, and may be omitted. The purified and aerated water is
drawn off at the bottom of the annular space D for use. In cases where there is not
a sufficient head of water to drive the turbine, the fan or blower would be worked
by other means.
A pipe O is connected to the bottom of the precipitation chamber E for enabling
the latter to be washed out and the passage of the water to be reversed through
the filter whenever it is necessary to cleanse the same, the outlet through the pipe O
being normally closed.
Filters for drinking and potable water are constructed and operate in a similar way
to that before described, so far as the filtration and aeration of the water is concerned,
the precipitation and the forcible injection of air being however omitted and the water
being aerated merely by dripping in a divided condition through the annular space D
to which the air has free access. If the water supply to the filter be constant, as
where large quantities of filtered water are required, the inlet may be connected
directly to the bottom of the chamber E beneath the filtering medium, and the filtered
water be drawn off from the annular space D to the reservoir for filtered water which,
in that case, would not be contained in the filter itself.
Figures 6 and 7 represent a domestic filter similarly constructed, except that it has
a reservoir P for unfiltered water above the filter and communicating by a pipe F
leading down through the filter to the chamber E beneath. The bottom of the
reservoir P is in the form of a nozzle which makes a joint with, and projects into,
the pipe and an air inlet pipe L leads down through the cover of the reservoir P
and terminates centrally within the nozzle in order that the water in passing through
the latter shall induce an inflow of air to mingle with and aerate the water. Below
the chamber E and the annular space D is a reservoir B into which the filtered water

page_text: drips from the annular space D through holes in the bottom thereof. The vessel B is
suitably supported within the chamber C which is made in one with the reservoir R.
A valve attached to a float S in the reservoir R is fitted to close the lower end of
the pipe F when the reservoir R is full, in order to prevent overflow through the air
holes c in case of an excessive supply. The reservoir R is provided with a draw off
cock, and a cleaning out cock is fitted to the chamber E.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :
1. A filter having an inlet and settling chamber beneath the filter bed, a water
space above, and an overflow lip or equivalent dripping device, in a surrounding drip
chamber for receiving the filtered water, substantially as specified.
2. In combination with an upwardly acting filter, the method of maintaining the
efficiency of the filtering medium while working by introducing air into the water
before it traverses the filter bed, substantially as specified.
3. In combination with an upwardly acting filter having a settling chamber
beneath the filter bed, the method of precipitating matters in suspension by the
injection of a fining solution into the water on or before entering the settling
chamber, as described.
The combined strainer and intercepting trap substantially as specified.
Dated this 24th day of September 1ddd.
A. H. HOBSON.
C. H. ROSHER.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.