Improvements in and relating to Means and Apparatus for Filtering.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in and relating to Means and Apparatus for Filtering.
We, PAUL DAME, of 40, Rue de Rivoli, Paris, France, Chemist, Dr. HENRI
POTTEVIN, of 33, Rue Dutot, Paris, aforesaid, Chemist, and ALBERT PIAT, of 85,
Rue Saint Maur, Paris aforesaid, Founder, do hereby declare the nature of this
invention to be as follows:
This invention has for objects to improve the apparatus, means, and processes
employed in filtering liquids, to remove from the said liquids the micro-organisms
contained therein in suspension, and to prevent the said micro-organisms from
breeding in or on the actual filtering plate. The filtering plates or layers em-
ployed heretofore, whether of felt, of tissues or fabrics, or fibres or porcelain; of
stone ware, or even of cellulose, have not given the results that should be pro-
duced in the interests of public health and for ensuring the good quality and
the preservation of liquids.
Our primary aim is to manufacture a filtering plate which has a variable degree
of porosity, which is, at the same time unchangeable, unbreakable, and incapable
of deformation, which is, if required, absorbent and sterilizing, in addition to being
capable of filtering, which can be made at a low cost so that it can be discarded
and a new one substituted for it without great expense as soon as it is supposed
that its operation is becoming less efficient, which filters so perfectly that its
filtration can be considered as equal, in itself, to actual sterilization and which,
finally, allows of a simple and easy construction of filter, whether for household
use or for use on a large scale.
Figs. 1, 2, and 3 of the accompanying drawings are respectively an elevation
and two sections according respectively to the lines x and y z of a small filter
for household use constructed according to this invention and provided with one of
cur filtering plates having its edges and borders rendered impervious according
to our manufacture.
Fig. 4 is a detail-view, showing to a larger scale the position and the form of
the impervious peripheral joint or packing. We cover the edges and borders of
our filtering plates with either movable or fixed joints or packings such as this,
which are never separated from the plates, even when the latter are thrown away
after use.
"
Our filtering plate, the mode or process of preparation of which forms an im-
portant feature of this invention, is made of a pure cellulose of "special essence
produced from flax or hemp. In the case of filters for commercial use having a
large volume of delivery a certain quantity of cellulose of another kind may be
added to this flax or hemp cellulose, with the object of increasing to a greater or
less degree the filtering property or power of the plate. With this pure cellulose,
and according to the nature of the liquid to be filtered, we incorporate in the paste

page_text: before pouring it into the moulds, an insoluble antiseptic or absorbent product or
material which aids the said paste in sterilizing or clarifying the liquid to be
filtered these insoluble substances, when water is the liquid to be filtered, are
simply neutral, and tend by their presence, to increase the degree of porosity of
the plate, which is also done by the sterilizing or clarifying materials. We shall
now proceed to describe our process for preparing our plates, starting with the
tow as raw material from which our new cellulose is to be produced.
We divide the tow very finely, after treating with acids and washing in alkaline
water. We wash this tow in pure water, mix it in water, and pass the mixture
into a paper-pulp engine.
The kind of paste or pulp thus produced is poured in the desired quantity into
a tube which serves as a mould and which is open at both ends and rests with one
end upon a washer or disc of filtering-felt, whilst another piece of felt lightly
weighted by means of a metal washer or disc is placed upon the underlying
material. The lower felt washer or disc is supported by a filtering-grating or
strainer below which is a passage that communicates with a closed vessel in
which is a slight barometric vacuum; by this means a portion of the water con-
tained in the paste is drawn into this passage.
A certain quantity of water escapes, so that as soon as, by this means, the
magma of cellulose has been brought to a certain degree of dryness or consistency,
the upper washers or discs, both metallic and felt, are removed from each tube,
and the moulded block of cellulose is inverted and placed upon a third felt washer
or disc.
After this, the product is left uncovered to the air for a certain number
of hours, during which the disc or block of cellulose thus prepared becomes dry
and somewhat firm, and tends, by contracting, to become compact.
The cellulose discs thus obtained have already a sufficient degree of firmness to
allow of being readily manipulated. They are placed in a drying stove in which
each of them, weighted by means of a perforated metal washer or disc, is placed
upon another metal washer or disc, which is also perforated and which is in turn
supported on a strainer, screen, sieve, hurdle or grating. The discs are, in this
manner, subjected during several days to the heat of the stove and they dry slowly,
contracting and assuming a uniformly fine and homogeneous texture with a fracture
of a compact appearance similar to that of ivory or
corozo.
"3
The plates thus produced contract very considerably in all directions;
and they have a perfect filtering action, not only by virtue of the
extreme fineness of their pores but also by virtue of the special
property, possessed by cellulose produced from flax or hemp prepared
in the manner described, of preserving its homogeneity and texture whether
the plates are in a dry state or are wet and have been used for filtering for a long
period. Plates manufactured by the above-described processes, in contradis-
tinction to other similar plates of cellulose, do not swell, and do not choke up
their pores, or, if there is a slight addition of another quality of cellulose, they
swell very little.
When it is necessary to increase the porosity of the plates still further with
the object of increasing the amount and the duration of their delivery, we incor-
porate in the cellulose whilst it is in a state of paste or pulp, an insoluble foreign
substance in a state of fine powder. This substance, which enables a higher
degree of porosity to be imparted to the plate, is selected preferably from amongst
the antiseptic bodies or insoluble anti-microbic substances such as animal or
vegetable black or charcoal; tar or asphalts in powder, unless it is required for
filtering wines, beers and ciders, in which case these substances should be neutral;
such as kaolin or china clay, pumice-stone, infusorial earth.
The porosity of the filtering plate may be increased by the use of a sheet of
paper or the filtering tissue or fabric N₁₁ of less contractibility, than cellulose
paste, inserted in the course of manufacture between the lower felt washer or disc
of the mould and the cellulose paste, with the object of reducing the contraction

page_text: of the cellulose and of producing a less compact plate. The paper or tissue thus
inserted constitutes the surface at which the filtered liquid passes out; whilst
upon the other surface there may be applied, after manufacture, a simple sheet of
paper or filtering tissue N,11.
After the plates have been obtained by these processes in the desired shapes
and sizes, they are surrounded by a flat thin band of india-rubber, the two edges
of which apply themselves to the borders and the edge of each of the two faces.
This band forms a double joint on the borders of each plate by covering over the
edge.
In lieu of this band there may be employed a layer of a supple and impervious
material forming one piece with the plate. For this purpose, there may be used,
either a layer of collodion, india rubber, gutta percha, or gelatine osmolized or
osmotized with the object of giving greater thickness to the joint, cork in a
state of fine subdivision can be incorporated with these materials. This layer is
applied by immersing the edge in a suitable bath and drying the same.
Figs. 1, 2, 3, and 4 show sufficiently the manner of utilizing the filtering plates
employed by our process for the construction of a filter.
A and B are two plates of cast iron forming the bottom and the cover of a
household filter. The bottom plate A is generally fixed to the wall and to the
discharge-pipe. The other plate serving as a cover, is hinged to the bottom
plate. C and D are internal packings of tin. This metal is run into recesses
which are formed in the interior of the plates A and B, and are surrounded and
provided with holding devices or recesses of dovetail-shape, and the inner faces
are each provided with a recessed circular channel E or E¹ into which open small
vertical grooves For FI along which flows the liquid which is supplied through a
tubular union I or through which also flows the liquid which, after having been
filtered, passes out through a tubular union J. K is a tubular union for emptying
the filter. The filtering plate H is surrounded in a permanent manner with an
impervious peripheral packing H¹ and it is engaged and held between two strain-
in discs which serve to keep it in place and retain the grosser impurities. The
packing His intended to serve as a joint for the borders and the edge of the
plate. These discs, which hold the plate H tightly between them, and which can
be made of filtering stoneware, are generally of perforated sheet metal or of a
metallic cloth, and they are covered with gummed taffeta. The tightening of the
two cast-iron plates A-B upon the edges of the filtering plate is effected by
means of a hand wheel L that is screwed on the end of a bolt M, which is rotatable
about a pin N and can be inserted into a notch O. By means of this arrange-
ment, the filter can be rapidly opened, inspected, and cleaned, and the plate H
provided with its adhering joint or packing H¹ can be readily replaced and the
apparatus closed again.
To produce a filter of great filtering power for use on a commercial scale, it is
sufficient to arrange filtering plates of large dimensions provided with their
peripheral joint, large enough whilst obviating the risk of being broken,
sufficiently thick, and of any suitable number, in sliding frames prepared in the
same manner as the plates A and B and arranged and provided with means for
being tightened against one another after the manner of the disc of a filter-press,
the whole combined and operating in the same manner as in the case of the
plates A and B of the domestic filter illustrated in Figs. 1, 2, 3 and 4.
The plates prepared as herein before described, are placed with their packings,
from which they must never be separated, in a stove at 170°. Then they are
enclosed hermetically in impervious envelopes or bags.
1000
F. WISE HOWORTH.
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicants.

page_text: Improvements in and relating to Means and Apparatus for Filtering.
We, PAUL DAME, of 40, Rue de Rivoli, Paris, France, Chemist, Dr. HENRI
POTTEVIN, of 33, Rue Dutot, Paris aforesaid, Chemist, and ALBERT PIAT, of 85,
Rue Saint Maur, Paris aforesaid, Founder, 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 has for objects to improve the apparatus, means, and processes
employed in filtering liquids, to remove from the said liquids the micro-organisms
contained therein in suspension, and to prevent the said micro-organisms from
breeding in or on the actual filtering plate. The filtering plates or layers em-
ployed heretofore, whether of felt, of tissues or fabrics, or fibres or poreclain, of
stone ware, or even of cellulose, have not given the results that should be pro-
duced in the interests of public health and for ensuring the good quality and
the preservation of liquids.
Our primary aim is to manufacture a filtering plate which has a variable degree
of porosity, which is at the same time unchangeable, unbreakable. and incapable
of deformation, which is, if required, absorbent and sterilizing in addition to being
capable of filtering, which can be made at a low cost so that it can be discarded
and a new one substituted for it without great expense as soon as it is supposed
that its operation is becoming less efficient. which filters so perfectly that its
filtration can be considered as equal, in itself, to actual sterilization and which.
finally, allows of a simple and easy construction of filter, whether for household
use or for use on a large scale.
Figs. 1, 2 and 3 of the drawings filed with our Provisional Specification are
respectively an elevation and two sections according respectively to the lines a
and y z of a small filter for household use constructed according to this invention
and provided with one of our filtering plates having its edges and borders ren-
dered impervious according to our manufacture.
Fig. 4 is a detail-view. showing to a larger scale the position and the form of
the impervious peripheral joint or packing. We cover the edges and borders of
our filtering plates with either movable or fixed joints or packings such as this,
which are never separated from the plates, even when the latter are thrown away
after use.
دو
Our filtering plate, the mode or process of preparation of which forms an im-
portant feature of this invention, is made of a pure cellulose of "special essence
produced from flax or hemp. In the case of filters for commercial use having a
large volume of delivery a certain quantity of cellulose of another kind may be
added to this flax or hemp cellulose, with the object of increasing to a greater or
less degree the filtering property or power of the plate. With this pure cellulose,
and according to the nature of the liquid to be filtered, we incorporate in the paste
before pouring it into the moulds, an insoluble antiseptic or absorbent product or 4
material which aids the said paste in sterilizing or clarifying the liquid to be
filtered these insoluble substances, when water is the liquid to be filtered, are
neutral and simply increase the degree of porosity of the plate, which is also
done by the insoluble substances when they aid in sterilizing or clarifying. We
shall now proceed to describe our process for preparing our plates. starting with 4
the tow as raw material from which our new cellulose is to be produced.
water.
We divide the tow very finely, after treating it with acids and washing in alkaline
We wash this tow thus treated in pure water, mix it with water, and
pass the mixture through a paper-pulp engine.

page_text: The kind of paste or pulp thus produced is poured in the desired quantity into
a tube which serves as a mould and which is open at both ends and rests with one
end upon a disc of filtering-felt, whilst another piece of felt lightly
weighted by means of a metal disc is placed upon the underlying
material. The lower felt disc is supported by a filtering grating or
strainer, below which is a passage that communicates with a closed vessel in
which is a slight barometric vacuum; by this means a portion of the water con-
tained in the paste is drawn into this passage.
A certain quantity of water escapes, so that as soon as, by this means, the
magma of cellulose has been brought to a certain degree of dryness or consistency,
the upper discs, both metallic and felt, are removed from each tube, and the
moulded block of cellulose is inverted and placed upon a third felt disc. After
this, the product is left uncovered to the air for a certain number of hours, during
which the disc or block of cellulose thus prepared becomes dry and somewhat
firm, and tends, by contracting, to become compact.
The cellulose discs thus obtained have already a sufficient degree of firmness to
allow of being readily manipulated. They are placed in a drying stove in which
each of them, weighted by means of a perforated metal disc, is placed upon an-
other metal disc, which is also perforated and which is in turn supported on a
strainer or grating. The cellulose discs are, in this manner, subjected during
several days to the heat of the stove and they dry slowly, contracting and assuming
a uniformly fine and homogeneous texture with a fracture of a compact appear-
ance similar to that of ivory or corozo."
The plates thus produced contract very considerably in all directions;
and they have a perfect filtering action, not only by virtue of the
extreme fineness of their pores but also by virtue of the special
property, possessed by cellulose produced from flax or hemp prepared
in the manner described, of preserving its homogeneity and texture whether
the plates are in a dry state or are wet and have been used for filtering for a long
reriod. Plates manufactured by the above-described processes, in contradis
tinction to other similar plates of cellulose, do not swell, and do not choke up
their pores, or, if there is a slight addition of another quality or cellulose, they
swell very little.
When it is necessary to increase the porosity of the plates still further, with
the object of increasing the amount and the duration of their delivery, we incor-
porate in the cellulose whilst it is in a state of paste or pulp, an insolubie foreign
substance in a state of fine powder. This substance, which enables a higher
degree of porosity to be imparted to the plate, is selected preferably from amongst
the antiseptic bodies or insoluble anti-microbic substances such as animal or
vegetable charcoal or tar or asphalts in powder, unless it is required for filtering
wines, beers, and ciders, in which case the substance should be neutral; as kaolin
or china clay, pumice-stone, and infusorial earth.
The porosity of the filtering plate may be increased by the use of a sheet of
paper or the filtering tissue or fabric N₁₁ of less contractibility than cellulose
paste, inserted in the course of manufacture between the lower felt disc of the
mould and the cellulose paste, with the object of reducing the contraction of the
cellulose and of producing a less compact plate. The paper or tissue thus in-
serted constitutes the surface at which the filtered liquid passes out; whilst upon
the other surface there may be applied, after manufacture, a simple sheet of
fitering paper or tissue N,1.
After the plates have been obtained by these processes in the desired shapes
and sizes, they are each surrounded by a flat thin band of india-rubber, the two edges
of which apply themselves to the borders and the edge of each of the two faces.
This band forms a double joint on the borders of each plate by covering over the
edge, and is never separated from the plate, even when the latter is thrown away
after use.

page_text: In lieu of this band there may be employed a layer of a supple and impervious
material forming one piece with the plate. For this purpose, there may be used
either a layer of collodion, india-rubber, gutta-percha or osmolized gelatine; with
the object of giving greater thickness to the joint cork in a state of fine sub-
division can be incorporated with these materials. This layer is applied by im-
mersing the edge in a suitable bath and drying the same.
Figs. 1, 2, 3, and 4 show sufficiently the manner of utilizing the filtering plates
produced by our process, for the construction of a filter.
A and B are two plates of cast iron forming the bottom and the cover of a
household filter. The bottom plate A is generally fixed to the wall and to the
discharge-pipe. The other plate serving as a cover, is hinged to the bottom
plate. C and D are internal packings of tin. This metal is run into recesses
which are formed in the interior of the plates A and B and are surrounded and
provided with holding devices or recesses of dovetail-shape, and the inner faces
of the packings C and D are each provided with a recessed circular channel E
or E into which open small vertical grooves F or F along which flows the liquid
which is supplied through a tubular union I or through which flows the liquid
which, after having been filtered, passes out through a tubular union J. K is a
tubular union for emptying the filter. The filtering plate H is surrounded in a per-
manent manner with an impervious peripheral packing H¹ and it is engaged and
held between two straining discs which serve to keep it in place and retain the
grosser impurities. The packing H¹ is intended to serve as a joint for the bor-
ders and the edge of the plate. These discs, which hold the plate H tightly
between them, and which can be made of filtering stoneware, are generally of
perforated sheet-metal or of a metallic cloth, and they are covered with gummed
taffeta. The tightening of the two cast-iron plates A and B upon the edges of the
filtering plate is effected by means of a hand-wheel L that is screwed on the end
of a bolt M, which is rotatable about a pin N and can be inserted into a notch 0.
By means of this arrangement, the filter can be rapidly opened, inspected, and
cleaned, and the plate H provided with its adhering joint or packing H¹ can be
readily replaced. and the apparatus closed again.
To produce a filter of great filtering power for use on a commercial scale, it is
sufficient to arrange filtering plates of large dimensions provided with their
peripheral joints, large enough whilst obviating the risk of being broken,
sufficiently thick, and of any suitable number, in sliding frames prepared in the
same manner as the plates A and B and arranged and provided with means for
being tightened against one another after the manner of the discs of a filter-press,
the whole combined and operating in the same manner as in the case of the
plates A and B of the domestic filter illustrated in Figs. 1. 2. 3 and 4.
The plates prepared as herein before described, are placed with their packings,
from which they must never be separated, in a stove at 170°. Then they are
enclosed hermetically in impervious envelopes or bags.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that what
we claim is: -
1. A filtering-plate H made of highly refined flax or hemp cellulose which is
mixed with water, then moulded, and finally agglomerated by drying and con-
traction, substantially as herein before described.
2. A plate H according to the preceding claim in the paste of which there has
been incorporated an insoluble neutral substance with the object of increasing the
degree of porosity of the plate.
3. A plate H according to Claim 1 in the paste of which there has been incor-
porated an insoluble antiseptic or absorbent material with the objects of increasing
the degree of porosity of the plate and of co-operating with the filtering proper to
produce sterilization or clarification.

page_text: 4. A filtering-plate H according to Claim 1, 2, or 3, provided with an impervious
peripheral packing H¹ formed either of a thin band of india-rubber having turned-
over edges or by a suitable adhesive supple layer for the purpose of forming a
tight joint substantially as described.
5. A filtering-plate H according to Claim 1, 2, 3, or 4, to which there is applied
in the course of manufacture a sheet of paper or fabric N₁ of less contractibility
than cellulose paste, interposed between the lower felt disc of the mould and the
cellulose paste poured into the said mould, the said paper or fabric being applied
with the object of diminishing the contractibility of the pure cellulose and forming
the face of the plate at which the filtered liquid is to pass out, whilst upon the
other face there is applied a sheet of paper or tissue N₁", which may be simply
applied after manufacture, substantially as hereinbefore described.
G. A filtering-plate H according to Claim 1, 2, 3, or 4, to which, after the said
plate has been manufactured, there is applied upon the face at which this filtered
liquid is to enter the plate a sheet of filtering paper or tissue N,"
7. The insertion of a filtering-plate H according to Claim 1, 2, 3, 4, 5, or 6
between two perforated straining or filtering supports resting upon grooved or
fluted surfaces of cast tin, one belonging to the bottom and the other to the cover
of a domestic filter, the said bottom and cover being hinged together and provided
with hinged tightening bolts, substantially as herein before described with reference
to and shown in Figs. 1, 2, 3, and 4 of the drawings referred to.
8. The insertion of filtering-plates of large size and similar to that referred to
in Claim 1, 2, 3, 4, 5, or 6, between successive perforated and filtering or straining
supports which in their turn rest against the grooved faces of sliding discs pro-
vided on each of their said faces with a layer of cast tin formed with vertical
grooves communicating with a peripheral channel, one of the grooved faces receiv-
ing the liquid to be filtered, and the other receiving and discharging the filtered
liquid, and the said discs being arranged, and provided with means for being
tightened, against one another after the manner of the discs of a filter-press in
such a way as to constitute a filter for commercial use having great filtering
power or capacity, substantially as hereinbefore described.
1011
1000
F. WISE HOWORTH.
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicants.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicants.