Improvements in Water Filters for Household Use.
Year: 1896

page_text: Date of Application; 18th Mar., 1896 Accepted, 9th. My, 18º6
COMPLETE SPECIFICATION.
Improvements in Water Filters for Household Use.
1, FRANCISKUS HENDRIKUS EYDMAN of 161, Rotterdamsche Weg, Delft, in the
Kingdom of Holland, 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 filters employed at present for filtering water for household use have all
some fault or other. All confidence has been lost in the old filters in which the
filtering layer consisted of sand or of charcoal because they are incapable of keeping
back the bacteria, and only give to the water a delusive appearance of being pure,
which is the more dangerous because this appearance may conceal great dangers to
health. Even the more recent filters which are capable of supplying water free
from bacteria still leave much to be desired. Their yield is very restricted, if not
at the beginning, at least after a short period of use; whilst when the water under-
going filtration contains matters which cover the filtering surface with a layer this
layer becomes quickly impermeable to the water and thus renders the filter unfit
for further use. Recourse must then be had to a thorough cleansing of the filtering
surface, but as such cleansing is a difficult operation even to experienced persons,
and is therefore so to speak impossible of realization by ordinary individuals it is
quite obvious that such filters however correct their principle may be, can never
come into general use. but that their employment will always be extremely
limited.
Now my new filter for filtering water for household use has for its object to
place the advantages of the other systems within the reach of all persons whilst
avoiding the defects of such filters.
Like my filter for industrial purposes which has been patented in various
countries and which is designed for filtering large quantities, the present improved
filter for domestic use is also based on an automatic and continuous removal of the
impurities deposited by the water, but it does not comprise the application of
the principle of the said industrial filter, namely, the maintenance of the initial
velocity of the water to be filtered by means of the reduction of the cross-sectional
area of the passages in proportion to the diminution of the volume, because this is
superfluous in the case, of the present filter.
In the accompanying drawing which illustrates my new filter:-
Figure 1 is a view in transverse section. and
Figures 2 and 3 are views in section on lines mn and kl respectively in
Figure 1.
Throughout the views similar parts are marked with like letters of reference.
Referring to the drawing A is a chamber serving as a reservoir into which the
water to be filtered flows. B B' are covers for receiving the filtered water which
is discharged by the tap C. D, D are partitions arranged in the chamber and to
which there are corresponding ribs D' on the covers. E is the filtering medium or
layer held tight by means of plugs and screws between the covers B B and the
chamber A. The arrangement is such that the only path which the water can
take in order to pass from the chamber A into the covers B and B', lies in its
passage through the filtering composition E. The chamber A has two openings F, G.

page_text: These openings are situated so that the closed filter can be readily connected in
with the water pipe of any dwelling house. When the filter has been placed in
position, it is continuously subjected to the pressure existing in the said water pipe.
As all the water used in the house is compelled to flow through the chamber A
with a great velocity, it must flow along the filtering surface. In order to be
always able to maintain the greatest possible velocity, the filter (as regards the
dimensions of the aforesaid passages) should always be selected so as to be in
proportion to the dimensions of the cross sectional area of the main pipe supplying
the house, and the filter is placed preferably below the lowest tap in the house.
By reason of the pressure which is constantly existing in the filter, it yields, even
with the least porous filtering medium which does not allow any bacterium at all
to pass through, a quantity of potable water (for drinking) sufficient for daily use.
Every time water is taken, anywhere in the house, the said water flows with great
force and velocity through the chamber A and along the filtering surface, so that
the latter is always very clean without such cleansing having to depend on the
attention given by the servants who are not to be depended upon in this repect,
and who usually give very little heed to things that are so necessary to health.
However at the end of a certain period it will be necessary to renew the filter on
account of its having lost in some degree (however small such degree may be) of
its filtering properties. Now the filter can be rendered anew fit for use by renewing
the filtering medium, either by heating the filter, unopened, up to a temperature
of 260° Fahrenheit or more during a certain length of time, which is an easy and
quite inexpensive operation. If the filters situated in one parish are placed under
authorized bacterialogical inspection and control, and they are renewed as soon as
bacteria begin to appear in the filtered water, then we have here all that is necessary
in order to safeguard the public health in the matter of drinking water. The
selection of the filtering medium is of course of great importance. Organic
substances such as cloth, silk, felt, paper etc. form a dangerous field of cultivation.
Chinaware should be made strong enough to withstand the great pressure of the
service water pipe. I therefore preferably employ a filtering layer of asbestos
paper or asbestos cardboard of suitable thickness, enclosed on both sides between
asbestos textile fabrics of sufficient thickness, first for the purpose of imparting to
the cardboard or paper sufficient strength to resist the pressure of the water, and
second for the purpose of protecting it against the wear and tear that might be
caused by the passage of water having great force and velocity. For this last
purpose however a piece of fine metallic woven fabric might also be used. In
this case I mix with the pulp that is employed to form the asbestos paper or
cardboard, different quantities of protoxide of iron, sesqui-oxide of iron, sesqui-
oxide of manganese, and protoxide of manganese, or the hydrated compounds of
these substances or of mixtures thereof, with the object of utilizing their oxidising
properties for destroying organic bodies and for annihilating the bacteria.
The filter may be of round, square or elliptical shape, and of any desired
dimensions. It may be made of glass, stoneware or of metal. I however prefer
to make it of cast iron coated or lined with a non-metallic euamel. It may also be
employed for filtering other liquids.
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
claim is :-
'
(1.) The improved water filter, constructed and arranged to operate, substantially
as hereinbefore described.
(2.) A water filter adapted to be placed in the high pressure service pipe of
dwellings, consisting essentially of a chamber such as A having a sinuous passage
formed by partitions D and inlets and outlets F and G, of covers B and B to the
latter of which is attached a draw-off. cock or tap C, of sheets or layers E of
filtering material such as asbestos woven fabric, and asbestos paper or asbestos

page_text: cardboard, either alone or combined, of iron or of manganese with oxygen and its
hydrates, as and for the purpose set forth.
Dated this 18th day of March 1896.
ROBERT E. PHILLIPS, Assoc. M. Inst. C.E., M.I. Mech. E.,
Consulting Engineer and Patent Agent,
70, Chancery Lane, London, W.C., Associate Agent.