Year: 1895

page_text: We, COUNT RUDOLF WESTPHALEN of I Reichsrathstrasse 13 and BARON
FRANZ VON KUHN, of VIII Auerspergstrasse 13 both of Vienna, in the Empire
of Austria, do hereby declare the nature of this invention to be as follows:
This invention relates to an improvement in such filters as are provided with a
filtering material consisting of fine fibres loosely interposed between two perforated
bottoms (upper and lower sieve), one of which retains the coarser impurities, whilst
the other allows the outflow of the purified liquid that has passed through the
filtering material.
The filters of this system, whilst possessing many advantages, have the incon-
venience of discharging but small quantities of filtered product, owing to the fine
fibres constituting the filtering material, becoming to a certain extent felted above
the lower sieve bottom and thus filling up the perforations of the latter, with the
result that the discharge then becomes comparatively slow.
In order to obviate this defect, we have invented an improvement consisting in
reducing the section of the discharge aperture to a size considerably smaller than
that of the filtering surface proper.
Correspondingly to the relation between the sections of the admission and
discharge apertures, a thin filtering layer will form itself on the lower sieve, and
above that layer the greater part of the filtering material will be distributed, so to
say, in suspension within the liquid to be filtered, whilst not ceasing to form an
important element of the active filtering body.
The filtering material is cleaned in the simplest manner by removing the upper
sieve, pouring water into the filter, constantly stirring the filtering material in order
to wash it, until the water flows out muddy, thereafter removing the fibrous
material, pressing the water out of it, then, if opportunity is afforded, drying it
in the sun or on a fire; in the latter case absolute certainty will be procured that
all the germs retained by the filtering mass have been destroyed.
The accompanying drawing shows diagrammatically a central vertical section of a
filter improved according to our invention.
The vessel A receives the liquid to be filtered; between the two perforated
bottoms a and a' is loosely interposed the filtering material 6 consisting of fine
fibres, preferably asbestos, and filling only a part of the interval between the two
bottoms.
Below the lower sieve, the vessel A gradually tapers into a funnel shaped
cavity A', the discharge aperture c of which has a section considerably smaller
than the sum of all the perforations in the upper sieve a through which the liquid
to be filtered has to pass before reaching the filtering layer. This narrowing of
the section of the discharge aperture e prevents the fine fibres of the filtering
inaterial from agglomerating (felting) too strongly, and consequently the liquid
runs rapidly through the apparatus without the quality of the filtrate being in the
least impaired.
At the same time a condition essential to the good working of the filter is that
the upper sieve a¹ should be kept at a suitable unvarying distance from the lower

page_text: bottom a, so as not to disturb the position of the filtering mass resting on the latter
or floating in suspension above it up to a certain height.
Dated this 30th day of March 1895.
HARRIS & MILLS.
23 Southampton Buildings, London, W.C., Agents.
A Filter for Liquids.
We, COUNT RUDOLF WESTPHALEN, of I Reichsrathstrasse 13, and BARON
FRANZ VON KUHN, of VIII Auerspergstrasse 13, both of Vienna, in the Empire
of Austria, 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 :-
This invention relates to an improvement in such filters as are provided with
a filtering material consisting of fine fibres loosely interposed between two
perforated bottoms (upper and lower sieves), one of which retains the coarser
impurities whilst the other allows the outflow of the purified liquid that has passed
through the filtering material:
The filters of this system, whilst possessing many advantages, have the incon-
venience of discharging but small quantities of filtered product owing to the fine
fibres constituting the filtering material becoming to a certain extent felted above
the lower sieve bottom and thus filling up the perforations of the latter, with the
result that the discharge then becomes comparatively slow.
In order to obviate this defect we have invented an improvement consisting in
reducing the section of the discharge aperture to a size considerably smaller than
that of the filtering surface proper.
Corresponding to the relation between the sections of the admission and
discharge apertures, a thin filtering layer will form on the lower sieve, and above
that layer the greater part of the filtering material will be distributed, so to say,
in suspension within the liquid to be filtered, whilst not ceasing to form an
important element of the active filtering body.
The filtering material is cleaned in the simplest manner by removing the upper
sieve, pouring water into the filter, constantly stirring the filtering material in
order to wash it until the water flows out muddy, thereafter removing the fibrous
material, pressing the water out of it, then, if opportunity is afforded, drying it
in the sun or on a fire; in the latter case absolute certainty will be procured that
all the germs retained by the filtering mass have been destroyed.
The drawing accompanying our Provisional Specification shows diagramatically
a central vertical section of a filter improved according to our invention.
The vessel A receives the liquid to be filtered; between the two perforated
bottoms a and a¹ is loosely interposed the filtering material consisting of fine
fibres, preferably asbestos, and filling only a part of the interval between the two
bottoms.
Below the lower sieve the vessel A gradually tapers into a funnel-shaped
cavity A, the discharge aperture c of which has a sectional area considerably
smaller than the sum of all the perforations in the upper sieve a through which the
liquid to be filtered has to pass before reaching the filtering layer. This narrowing
of the sectional area of the discharge aperture c prevents the fine fibres of the
filtering material from agglomerating (felting) too strongly and consequently the
liquid runs rapidly through the apparatus without the quality of the filtrate being
in the least impaired.
At the same time a condition essential to the good working of the filter is that
the upper sieve a' should be kept at a suitable unvarying distance from the lower

page_text: bottom a so as not to disturb the position of the filtering mass resting on the latter
or floating in suspension above it up to a certain height.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that
what we claim is :-
1. In filters having their filtering material, consisting of fine fibres, loosely
interposed between two perforated bottoms or sieves, a receiving cavity A'
situated beneath the lower bottom a and the discharge aperture of which has
a sectional area much smaller than the sum of all the perforations in the upper-
sieve in such a manner that a great part of the filtering material remains floating
in suspension in the liquid to be filtered, substantially as described.
2. The improved filter for liquids substantially as herein shown and described.
Dated this 24th day of August 1895.
HARRIS & MILLS,
23 Southampton Buildings, London, W.C., Agents.
HARRIS & MILLS,
23 Southampton Buildings, London, W.C., Agents.