Year: 1886

page_text: I, WALLACE CHRISTOPHER NICKELS 55 Ockendon Road, Essex Road Islington
London N. Middlesex, Engineer do hereby declare the nature of this invention to
be as follows:-
=
Filtering funnels are usually made either with smooth or ribbed or corrugated
sides. When smooth, the filter paper presses closely to the side and filtration is
therefore slow, especially when the liquid to be filtered is thick.
The object of the corrugations, is to accelerate filtration by providing air spaces
between the filter paper and the sides of the funnel.
Sometimes this is effected by suspending small glass rods with tops bent into a
hook in the funnel.
However both these methods render the filter paper liable to breakage, especially
when it has to be washed with alkaline liquors.
I have found that by using a double funnel these disadvantages are removed
and filtration greatly accelerated.
The outer funnel is made with smooth sides, and has ridges or projections
thereon, which serve as a bearing for the second or inner funnel, which has plain
sides, which are perforated or drilled with holes.
The distance of the inner funnel from the outer is immaterial, but I find to
of an inch is the best.
The filter paper being placed in the inner funnel, is filled with the liquid to be
filtered; it runs through the paper; thence through the perforations or holes and
has a free exit between the two funnels.
In no case must the perforation of the inner funnel be large enough to cause
breakage of the filter paper by its being forced through them; I find 7 of an inch
the best size.
I may either make the double funnel in one, or I may make the inner perforated
funnel detachable, with longitudinal ribs or projections on the outside so that it
can be placed in ordinary funnels, but it must be kept to of an inch from the
outside funnel: or I may make the inner funnel detachable and have the pro-
jections or ribs made on the outside funnel, so as to keep the former the necessary
distance from the latter funnel.
When an ordinary funnel is used in connection with a vacuum pump, there is a
great danger of breaking the filter paper at the apex; to remedy this it is usual to
insert a cone of platinum,

page_text: If my double funnel is made with the space between the two funnels at the top
closed with a stopper for cleaning; it may be used in connection with an air pump
with the utmost advantage, the whole surface of the inner funnel being exposed to
the vacuum; there is no risk of breaking the paper, and filtration is wonderfully
rapid.
In some cases it is desirable to wash the back of the filter paper, while in the
funnel, usually this is tedious, risky and unsatisfactory.
With the double funnel the space between the two funnels can be filled with
wash water, which finds its way through the back of the filter paper and material
on it, into the interior .of the funnel and thence out through the bottom; thus
acting precisely like a washing filter press.
The principle of my invention has long been applied to filter presses; filtration
is very slow where the filter cloth rests upon the ribs of the filter press (corre-
sponding to the sides of an ordinary funnel) but when these ribs are covered with
a perforated metal sheet (corresponding to my inner perforated funnel) filtration is
greatly quickened.
My double funnel therefore gives quicker filtration; enables filter paper and
substance to be washed quicker; diminishes risk of breaking filter paper.
Can be used in a flask or vessel into which it fits tightly as the space between
the outer and inner funnel; allows the air in the vessel to escape; an ordinary
funnel must fit loosely into the vessel.
23 30

page_text: 7
Improvements in Filtering Funnels..
I, WALLACE CHRISTOPHER NICKELS, of 23 Cleveland Road, Downham Road;
Islington, London, 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 :-
-
Filtering funnels are usually made either with smooth, ribbed, or corrugated
sides; when smooth, the filter paper presses closely to the sido and filtration is
therefore slow, especially when the liquid to be filtered is thick.
The object of the corrugations, is to accelerate filtration by providing air spaces
between the filter paper and the sides of the funnel.
Sometimes this is effected by suspending small glass rods with tops bent into a
hook in the funnel.
However both these methods render the filter paper liable to breakage, especially
when it has to be washed with alkaline liquors.
I have found that by using a double funnel these disadvantages are removed,
and filtration greatly accelerated.
The outer funnel is made with smooth sides and has ridges or projections thereon
which serve as a bearing for the second or inner funnel which has plain sides, the
same being perforated or formed with holes.
The distance of the inner funnel from the outer one is immaterial, but I find it
advantageous to have about one sixteenth to one quarter of an inch space between
the two.
The filter paper or other filtering medium being placed in the inner funnel, it is
filled with the liquid to be filtered; it filters through the paper; thence through
the perforations or holes and finds a free.exit at the bottom, as in the case of an
ordinary funnel.
In no case must the perforations of the inner funnel be large enough to cause
breakage of the filter paper, by its being forced through them; I find that holes of
about one sixteenth to one eighth of an inch are of suitable size.
I either make the double funnel in one as represented in Figures 1 and 2 of the
drawings annexed or I make the inner perforated funnel detachable; with longi-
tudinal ribs or projections on the outside, so that it can be placed in ordinary
funnels, but it must be kept one sixteenth to one quarter of an inch from the
outside funnel. Or I make the inner funnel detachable, and have the projections
or ribs made on the inner surface of the outside funnel, so as to keep the two a
suitable distance apart.
When an ordinary funnel is used in connection with a vacuum pump, there is
great danger of breaking the filter paper at the lower or bottom end of the cone;
to prevent this it is usual to insert a hollow cone of platinum.
Now if my improved double funnel is made with the space between the two
funnels at the top, closed and with a stopper for cleaning as shown by Figures 3
and 4 of the drawings, it may be used in connection with an air pump, with
advantage, the whole surface of the inner funnel being exposed to the vacuum;
there is very little risk of breaking the paper, and filtration is extremely rapid.

page_text: In some cases it is desirable to wash the back of the filter paper while in the
funnel; usually this is tedious, attended with risk and uncertain,
With the double funnel the space between the two funnels can be filled with
wash water, which finds its way through the back of the filter paper and material
upon it into the interior of the funnel and thence out through the bottom, thus
acting in a similar manner to a washing filterpress.
My improved double funnel has the following advantages viz quicker filtration;
it also enables the filter paper and any substance thereon to be washed more
quickly; diminishes risk of breaking filter paper, enables filter paper and precipitate
thereon to dry much more quickly in an air or water bath; by reason of current
of hot air passing through the space between inner and outer funnel.
It can be used in a flask or vessel into which it fits tightly, as the space between
the outer and inner funnel allows the air in the vessel to escape; an ordinary
funnel must fit loosely into the vessel, or it will not filter.
.
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:
The improved construction of filtering funnels by forming them double with a
space between the two the inner funnel being.so perforated as to support the filter
paper or other filtering medium substantially in the manner and for the purpose
herein before fully described and represented in the drawings annexed.