Improvements relating to the Filtration of Water and to Apparatus therefor.
Year: 1888

page_text: Date of Application, 24th Oct., 1888
Complete Specification Left, 24th July, 1889-Accepted, 21st Sept., 1889
Improvements relating to the Filtration of Water and to Apparatus
therefor.
I, GEORGE DAVID GERSON, Doctor of Philosophy, of Hamburg in the Empire
of Germany, Chemist, do hereby declare the nature of this invention to be as
follows:-
My invention comprises improvements in the method and apparatus_for_con-
tinuously purifying water, which is effected by first separating by means of a filter,
matters mechanically suspended in the water to obtain clear water for industrial
purposes, and then converting the latter by means of a second filtration into water
suitable for drinking purposes which becomes of a quality not inferior to spring-
water.
The primary filtration is effected under a pressure of about a 5 metre water-column
while the secondary filtration may take place under a pressure of 0.8 metre. The
primary filtration is effected through duly impregnated pumice-stones of different
size and sponges, or through the latter alone, and both these porous substances are
previously treated by an insoluble iron-salt, such as ferro-tannate, in order to remove
all impurities from the filtering materials soluble in water. For the secondary filtra-
tion only layers of impregnated pumice stones of different granulation are required.
The treatment of the sponges with ferro-tannate is also for the purpose of separating
their organic properties without the loss of their natural elasticity.
For this reason the sponges and the pumice-stones are submerged for four to ten
days in a solution of an iron-salt preferably of sulphate of iron, or ferrum sexi-
chloricum, or perchloride of iron, until thoy are fully impregnated and after any
adhering crystals are carefully washed off a dilute solution of tannic acid is poured
over the filtering materials until tannate of iron is formed throughout the same.
tannate of iron, forming an insoluble antiseptic precipitate in the press of the
filtering materials serves to prevent the development of any organic fermentative
germs.
The
In comparison with carbon the filtering materials employed by my process have the
advantage, that they are easily cleaned by reversing the flow of water in the filter
instead of revivifying their filtering or purifying qualities by the glowing-process, as
is necessary with vegetable or animal charcoal, commonly employed in filtering water
or other liquid.
These advantages for purifying water are considerably increased by the arrange-
ment of the apparatus therewith employed, as it allows a permanent working,
notwithstanding that the washing-out of the filtering materials or the renewal of the
same is required within certain periods.
In order to gain such advantages, I make use of duplicate-filtering apparatus in
each set of filters for both the primary and secondary filtering systems.
The apparatus employed for the primary filtration consist preferably of two
cylindrical upright vessels carried by trunnions supported on suitable pillar-blocks,
allowing the filters to be turned in the vertical plane. The impregnated filtering
sponges are placed between two sieves or perforated plates the lower one of which
being fitted loosely within the vessel and may be moved in the axial direction of the
latter by a screw extending through a stuffing-box below the lower end of the vessel; for
the purpose of pressing the sponges properly together, and to squeeze out the residual
impurities detained from the water. This pressing-out of the sponges is of great
advantage, as the cleaning of the same by properly cleaned water, which passes the
filtering materials in opposite direction of the flow of the water to be purified, will
be considerably facilitated.

page_text: The apparatus to be used for the secondary filtration are essentially of the same
construction, with the only difference, that the mechanism for pressing the filtering
material is omitted.
The operation of the apparatus is as follows:-
The water supplied from the main pipe of the water works or reservoir under a
certain pressure, enters near the bottom of the first set of filters through a pipe, and
a three-way-cock and two branches. The water passes upward through the impregnated
sponges, and where it is desired also through a layer of pumice-stones to the upper
pipes, which conduct the partly purified water to the second set of filters, placed at a
level below that of the primary filters.
After the water has passed the prepared pumice-stones of the second set of filters,
it is fit for drinking purposes, perfectly pure and clean.
Wherever local circumstances will allow, I prefer to arrange both sets of filters
(the primary and secondary) under equal pressure, it is then necessary however to
place the receptacle for the filtered water of the first set at about half the height of
the useful water-column.
Whenever the renewal of the filtering material is required either one of the filters
may be separated from the other by turning the three-way-cocks correspondingly,,
and then turning the one filter around its trunnions after which the upper cover can
be easily removed. During this time it is not necessary to discontinue the filtration,
as the water is in the mean time purified by the filter which is intact.
Dated this 24th day of October 1888
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements relating to the Filtration of Water and to Apparatus
therefor.
I, GEORGE DAVID GERSON, Doctor of Philosophy, of Hamburg, in the Empire of
Germany, Chemist, 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 relates to improvements in the method of and apparatus for purifying
water, and the object of the same is to provide means for continuously purifying water
by first separating matters mechanically suspended therein to obtain clear water for
industrial purposes, and then converting the latter by means of a second filtration
into water suitable for drinking purposes which becomes of a quality not inferior to
spring water.
The apparatus for carrying the invention into practice is illustrated in the accom-
panying drawings in which
Figure 1 shows an elevation of a pair of primary filters, partly in section.
Figure 2 represents the arrangement of a complete set of filters as employed for
continuous working.
Figure 3 is an elevation of a modification of the primary filters, also partly in
section, and
Figure 4 shows a side view of the same.
The primary filtration is effected under a pressure of about 5 metrè water-
column, while the secondary filtration may already take place under a pressure
of 0.8 metre.
In order to allow a permanent working notwithstanding that the washing out of
the filtering materials or the renewal of the same is required within certain periods
I make use of a series of filtering apparatus in each set of filters, for both the primary
and secondary filtering systems.
The apparatus employed for the primary filtration consists preferably of two or
more cylindrical upright vessels a a' carried by trunnions ³ ³ supported on

page_text: suitable pillar-blocks allowing the filters to be turned in a vertical plane. The.
filtering material in these filters consists of sponges c, preferably impregnated with
tannate of iron, forming an insoluble antiseptic precipitate in the pores of the filtering
materials and preventing the development of any organic fermentative germs, placed
between two sieves or perforated plates de the lower one being fitted loosely within.
the vessels a a¹ and may be moved in the axial direction of the latter by a screw f
extending through a stuffing-box below the lower end of the vessel, for the
purpose of pressing the sponges properly together and to squeeze out the residual
impurities detained from the water. This pressing out of the sponges is of great
advantage as the cleaning of the same by properly cleaned water which passes the
filtering materials in opposite direction of the flow of the water to be purified, will be
considerably facilitated. Upon the upper perforated plate e may be placed in certain
cases layers of pumice-stones of different sizes and previously treated by an insoluble
iron salt, such as tannate of iron.
The apparatus to be used for the secondary filtration are essentially of the same
construction with the only difference that the mechanism for pressing the filtering
materials is omitted in these secondary cylindrical vessels, only layers of impreg-
nated pumice-stones of different granulation being required.
The operation of the apparatus, Figures 1 and 2 is as follows:-
The water supplied from the main pipe i, of the water-works or reservoir / under
a certain pressure enters through the three-way cock the hollow trunnions ³ ³
and the branches near the bottom of the first set of filters a a¹. The water
passes upward through the impregnated sponges e and where it is desired also
through layers of pumice-stones to the upper pipes, which conduct the partly
purified water through the opposite bollow trunnions 3, 3, the branches k, ³, the
three-way cock 1, pipe ', three-way cock P, the hollow trunnions 13, 14 and the branch
pipes, near the bottom to the second set of filters bb' placed at a level below.
that of the primary filters.
The water passes again upward through the prepared pumice-stones and the
pipes m m to the hollow trunnions m³ m³, the branches m', m³ the three-way cock n
and the discharge-pipe o to a reservoir p.
After the water has passed the prepared pumice-stones of the second set of filters
it is fit for drinking purposes perfectly pure and clear.
Wherever local circumstances will allow, I prefer as a special improvement to
arrange both sets of fillers, (the primary and secondary) under equal pressure by
placing the receptacle p, for the filtered water of the second set level with the
primary set. By this arrangement the pressure in each set of filters is about half.
the height of the useful water column.
Whenever the filtering material needs to be cleaned this can be effected by previously.
filtered water, when reversing the flow of the water in the filter in a direction opposite:
to that which is employed for filtering purposes.
If it is intended to clean the filtering substances, for instance, in the vessel. a first
the cock g is opened and the three-way cock regulated so as to conduct the:
water from the main pipe i only into the vessel a and the three-way cock / so.
as to allow the water from the filter a' to enter into the vessel a through the upper
pipe k. This mode of cleaning the filtering substances within the apparatus itself
may be considerably improved by aid of the mechanism for squeezing out the sponges,
while the impurities are thus washed off from the filtering materials by the reversed
current of the water and drawn off through the cock y...
For cleaning the filtering material in the secondary filtering apparatus, for instance,
the vessel 6', the three-way cock is turned so as to allow the water coming from the
primary filtering apparatus only to enter the vessel b as at the same time the three-
way cock n is so regulated, that it conducts the water, previously filtered through the
vessel b, only into the vessel b¹ through the branch m¹ the impurities can be drawn off
through the cock g' at the bottom of the vessel b.
In most cases however I would prefer to employ the filtered water stored in the
reservoir p for cleaning the filtering substances in the vessels for the secondary

page_text: filtration, and for this reason the discharge pipe o can be brought in communica-
tion with the reservoir by means of a cock g at the bottom of the reservoir.
The water is then conducted through the pipe-system m² m² m, or mim³ m² in reversed
direction through the filtering substances in the apparatus and the impurities drawn.
off as aforesaid.
Whenever the renewal of the filtering materials is required either one of the filters
may be separated from the other. by. turning the respective three-way cock corre-
spondingly and then turning, the ono filter. around its hollow, trunnions, which are for
this reason.connected with the respective conducting pipes and, three-way cock. by
means of stuffing boxes, after, which the upper, cover may be easily removed. During
this time it is not necessary to discontinue the filtration entirely, as the water. is in the
mean time purified by the filters which. remain intact.
Instead of employing the trunnions of the filtering vessels. as conducting, pipes as
set forth, the three-way cock may be placed directly between the two. branches **
and and the three-way cock between the branches kand k as shown in figures 3
and 4. The water then passes through the pipe i, three-way cock i¹, branches, &,
filters a and a', branches k and k¹, three-way cock.l and. to the pipe 1, leading to the
second set of filters, the pipe-system, of which is similarly arranged as that of the
described primary filtering vessels, as will be easily understood by aid of the foregoing
references to figure 2 of the drawing. The filters are cleaned exactly, in the same
way as those shown in figures 1 and 2, by previously filtered water when reversing
the flow of the water in the filters in a direction opposite to that employed for filtering.
Only when the renewal of the filtering materials is required, the respective filtering-
vessel must be disconnected from the two three-way cocks. and or 12 and n in order
to allow the vessel to be turned around its trunnions.
I am aware that, prior to my invention,. filtering apparatus have been made
operating in conjunction with duly impregnated and prepared sponges. and pieces of
pumice-stones, in separate filtering vessels, 1 therefore do not claim such,a combina-
tion or system broadly..
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 what I
claim is
First. In apparatus for filtering water by primary and secondary filtration, the
combination of turnable primary and secondary filtering vessels a al and b b' arranged
in series, with the three-way cocks i¹land n.and the conducting pipes, substantially
as and for the purpose specified..
Second. In apparatus for filtering water, by primary and secondary filtration the
combination of turnable primary and secondary filtering vessels a a¹ and b b¹ arranged
in series, with the three-way. cocks and n;.the conducting pipes and hollow
trunnions, substantially as and for the purpose, set forth.
Third. In combination with the filtering vessels, serving for the primary filtration,
the perforated plates e and d,.the screw f, the stuffing-box f and a support containing
the female-thread-fitting to the screw, substantially as and for the purpose specified.
Dated this 24th day of July 1889.
HASELTINE, LAKE & Co.,
45,, Southampton Buildings, London, Agents for the Applicant.