Year: 1896

page_text: I, WOLF DEPRIES, of No. 4 Danes Inn, Strand, London, Engineer, do hereby
declare the nature of this invention to be as follows:-
It is often advantageous in the filtration of liquids to accelerate the operation by
delivering the liquid from the apparatus under a pressure exceeding that due to
gravitation.
For this purpose it has been customary either to create the desired pressure
either by using a force pump for supplying the apparatus with water to be filtered,
or by creating a partial vacuum in the chamber which receives the filtered water,
a part of the atmospheric pressure thus acting in the same way as that of the
pump, the vacuum being broken so as to allow the filtered water to be poured off
from the vessel or drawn off through a tap.
The first of these methods necessitates that the entire apparatus should be of a
weight and strength capable of resisting the pressure, besides having a joint of
the same resistance between the cover and the body of the reservoir of the unfil-
tered liquid. In adopting the second mentioned method it is impossible to
withdraw the filtered liquid before removing the atmospheric pressure; and it
thus becomes necessary after drawing off the liquid, to again create a vacuum in
the reservoir of filtered liquid, before filtration under atmospheric pressure
can be recommenced.
My invention has for object to avoid the inconveniences attaching to both
these methods.
It consists essentially in causing the filtrate to flow or drip within a tube or
closed chamber of any kind which is joined hermetically to the filtering vessel,
and in establishing a communication between this tube or chamber and an exhaust
pump provided with a branch for delivering the water. This pump may be an
ordinary pump or a lift and force pump; the essential point being that it must
both communicate with the collector which receives the filtered water, and be
furnished with a branch controlled by a suitable valve for delivery of filtered
water. This branch may allow the water to flow into portable receivers, or it
may be placed in or over a fixed receptacle of the filtrate. The lever by which
the pump is worked may at the same time operate a second pump for delivering
the unfiltered water to the filter or for raising the filtered water, if desirable, to
any height without reducing the effective pressure under which filtration takes
place; or this lever may if desired operate the auxiliary pumps for both pur-
poses. The two or the three pumps, or two of them, may be mounted on a common
axis; a construction which presents advantages for instance in the case of a
well-filter. When the form of the filtering substance or substances makes it
desirable, I may fit them with a hermetical joint within the chamber which
separates the filtered from the unfiltered water, and in this case this chamber or
diaphragm may form the upper part of the collecting vessel, or I may employ
tubular collectors, or others of suitable form as ordinarily used.

page_text: In cases where the filtering material or materials are hollow the partial vacuum
is produced therein at the same time as in the collector. I may allow filtration
under pressure of a vacuum to take place whilst the pump is not in action; and
for this purpose I may furnish the pump for filtered water with a valve, or a
delivery pipe or any other convenient accessory.
I, WOLF DEFRIES, of The Lawn, Thames Ditton, in the County of Surrey, (late
of No. 4 Danes Inn, Strand, London), 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:-
It is often advantageous in the filtration of liquids where within wide limits
the efficiency of filtration is independent of the pressure under which it is con-
ducted, to accelerate the operation by delivering the liquid from the apparatus
under a pressure exceeding that due to gravitation.
For this purpose it has been customary either to create the desired pressure
by using a force pump for supplying the apparatus with water to be filtered,
or by creating a partial vacuum in the chamber which receives the filtered water,
a part of the atmospheric pressure thus acting in the same way as that of the
pump, and the vacuum being broken so as to allow the filtered water to be poured
off from the vessel or drawn off through a tap.
The first of these methods necessitates that the entire apparatus should be of a
weight and strength capable of resisting the pressure, besides having a joint of
the samo resistance between the cover and the body of the reservoir of the unfil-
tered liquid. In adopting the second mentioned method it is impossible to
withdraw the filtered liquid before removing the atmospheric pressure; and it
thus becomes necessary after drawing off the liquid, to again create a vacuum in
the reservoir of filtered liquid, before filtration under atmospheric pressure
working against a partial vacuum can be recommenced.
My invention has for object to avoid the inconvenience attaching to both
these methods, and as will be seen on the accompanying drawing.
It consists essentially in causing the filtrate to flow or drip within a tube or
closed chamber B of any kind which is joined hermetically to the filtering vessel A,
and in establishing a communication between this tube or chamber B and an
exhaust pump E provided with a branch F for delivering the water. This pump
may be an ordinary pump or a lift or force pump; the essential point being that
it must both communicate with the collector which receives the filtered water,
and be furnished with a branch controlled by a suitable valve f for delivering
filtered water. This brauch may allow the water to flow into portable receivers,
or it may be placed in or over a fixed receptacle of the filtrate. The lever G by
which the pump E is worked may at the same time operate a second pump C for
delivering the unfiltered water to the filter or for raising the filtered water, if
desirable, to any height without reducing the effective pressure under which
filtration takes place; or this lever (+ may if desired, operate auxiliary pumps for
both purposes. The two or the three pumps, or two of them, may be mounted on

page_text: a common axis, a construction which presents advantages for instance in the case
of a well-filter. The reservoir of unfiltered water containing the filter is furnished
with an overflow or ball-cock D to keep the level of water as nearly constant as
may be desired.
When the form of the filtering substance or substances makes it desirable, I may
fit them with a hermetical joint within the chamber which separates the filtered
from the unfiltered water, and in this case this chamber or diaphragm may form the
upper part of the collecting vessel, or I may employ tubular collectors, or others
of suitable form, as ordinarily used. In cases where the filtering material or
materials are hollow the partial vacuum is produced therein at the same time as
in the collector.
I usually desire filtration under atmospheric pressure working against a vacuum
to take place whilst the pump is not in action; especially in those cases where
there is an intermittent demand upon the filter, such for instance as with a village
pump; and in such case I provido a large closed filtered water reservoir and a
valve on the pump to prevent overflow by syphonage. In this way each person
who draws water necessarily increasing the vacuum to such extent as he removes
water, leaves the filter working at a proportionately increased rate until the supply
of water is restored ready for the next comer.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declaro that what
I claim is:
1. A filter provided or connected with an air-tight filtered water chamber and
with a pump arranged to exhaust air and draw water from the same arranged
and operating for the purposes and substantially as described.
2. In combination with a filter as described in the last paragraph a pump on the
same axis or operated by 'he sanio lever as the exhaust pump in combination with
an overflow or ball-valve on the unfiltererd water reservoir containing the filter
for the purpose and as described.