IMPROVEMENTS RELATING TO THE TREATMENT OF VARIOUS MATERIALS BY THE EMPLOYMENT OF FILTER PRESSES
Year: 1878

page_text: LETTERS PATENT to Alexander Browne, of the Firm of Browne and Company,
Patent Agents, of 5, Southampton Buildings, Holborn, in the County of
Middlesex, for the Invention of "IMPROVEMENTS RELATING TO THE TREATMENT
OF VARIOUS MATERIALS BY THE EMPLOYMENT OF FILTER PRESSES." A com-
munication from abroad by George Bourdon, of Paris, France.
Sealed the 27th August 1878, and dated the 1st March 1878.
PROVISIONAL SPECIFICATION left by the said Alexander Browne at the
Office of the Commissioners of Patents on the 1st March 1878.
ALEXANDER BROWNE, of the Firm of Browne and Company, Patent Agents, of
"IMPROVEMENTS
5, Southampton Buildings, Holborn, in the County of Middlesex.
RELATING TO THE TREATMENT OF VARIOUS MATERIALS BY THE EMPLOYMENT OF
FILTER PRESSES." (A communication from abroad by George Bourdon, of Paris,
France.)
Filter presses are used in the manufacture of sugar, but have heretofore been little
applied in chemical manufactures, mainly because of inconveniences arising from the
construction of the presses.
According to this Invention filter presses are applied to various substances, such
as washing waters from wool and other materials, in sugar refineries, for treatment
of sewage and glairy liquids, in soap making, for phosphate precipitates and
muriatic acid, in the treatment of wine lees.
The liquids may be either acid or alkaline, and limpid or glairy. The filter
press must be modified accordingly.
For acid liquids the filter press is coated with paraffine where in contact with the
liquid;
it may be put on hot, but it is better, in order to form a long lasting
glaze, that the part should be heated to a bigh temperature.
The acid products may be limped. In that case the cloths should be steeped in a
preserving substance, and capable of making the apertures in the material as fine as
possible.

page_text: If the liquids are glairy they must be mixed with paper pulp or other analogous
material on which the liquid has only a feeble influence. In this case more
ordinary cloths may be employed than for limpid liquids.
For alkaline liquids it is desirable to use cloths that are not affected by them; for
this purpose the threads in the cloth are of metallic wire or enclosed in india-
rubber or other suitable material. Ordinary pumps are not suitable, but pumps
with bellows of india-rubber or other acid-resisting material are suitable, or wooden
pumps.
For most of the above materials the liquid has to be filtered repeatedly. For
this purpose the central conduit in the press is done away with, and the liquid
runs from the first chamber into the following between the two cloths, and so on as
often as desired.
In certain cases the press cake is of little value, the liquid alone being valuable;
thus, for instance, in treating caustic soda and potash, the charcoal in refineries,
wine lees, and aniline dyes, in such cases the cakes should be as dry as possible,
and for this purpose, according to this Invention, a pump working under a pressure
of at least 20 atmospheres is employed. All the liquid that escapes is collected
during the undoing of the filtering frames.
In other cases where the cake is the valuable part (for instance, in phosphate,
precipitates in the treatment of wash waters from wool and sewage) the cake in as
dry a state as possible is put in a hydraulic press for expressing the liquid remaining.
The filter press represents in that case only a first stage in the process.
In the treatment of wine lees, contact of the same with iron must be avoided.
In the construction of the filter press only oak or tinned copper must be exposed to
it. If muriatic acid is used in the tinning it will rapidly become detached by the
influence of the wine. The bags or cloths should be of cotton with close meshes,
and for a complete filtration should be coated with paste or good lees. Only with
these precautions a filter press can be employed for wine.
Waters resulting from washing of wool are first treated with acids as weak as
possible. They take up the alkaline sults, and free the fatty matters which are
mixed with the inert matters, such as carbon or sawdust. The whole is well
stirred, and by a pump or extractor conveyed to a filter press, which ought to be
coated internally with paraffine. The liquids running off contain salts with
alkaline base. The greasy matters form cakes, which are taken away, and tho
useful parts extracted in the usual manner. As to the limpid liquids they are used
again for washing fresh wool. This water is treated as before described, and brought
to the filter press for extraction of fatty and insoluble matters, and for rendering
limpid a liquid charged still more with salts of alkaline base. This liquid may thus
be methodically charged, and it will always be right to operate the solution of
the matters contained in the wool to saturation. A solution is finally obtained
sufficiently rich for evaporation, leaving as residues salts of potash or soda.
To avoid the decomposition of greasy matter into sulphates not having a
saponificant character and of less value than the oxydes of potash or soda, which
exist in a state of combination in the salts resulting from the washing, the
precipitation is preferably done by oxyde of calcium or any other salt capable of
being substituted for saponificant oxydes of potassium or sodium.
Each passage through the filter press gives a limpid liquid more caustic, and
which is treated by evaporation when the water has become sufficiently rich in
potash or quite deprived of the brick ashes which are retained in the press cakes.
These very alkaline liquids should be filtered through tissues not attacked by the
alkalies; for this purpose cloths are employed, as above described, or, better still,
made of wire gauze covered or not by a textile (not woven material), such as jute,
that withstands the action of the alkalies.
The system of methodical charging of liquids in the treatment of the wool wash
waters is almost only possible by the employment of the filter press, for decantation
will not do, all the liquid will not be obtained, and there will be a sensible loss.
If on the contrary the ordinary filtering process is used it takes much time to be

page_text: commercially possible, and the insoluble matters will always retain a quantity of
liquid. The filtering under pressure corrects these evils. It is in a general way
applicable to all chemical products for giving a result equivalent to that described
with regard to wool-washing water.
Whenever a liquid, by reason of re-action, contains insoluble matter and soluble
salts, the filter press may be employed for treating, so as to separate the liquids
which are rendered limpid. These limpid liquids may serve afresh as solvents,
instead of the water first employed, and when the re-action takes place they will
contain insoluble matters of the nature of the preceding ones, and a very strong
proportion of soluble salte, which are separated afresh by the filter press. The
liquid obtained will thus always be very limpid, and contain an increasing quantity
of soluble salts.
With certain materials, such as phosphate precipitates or manure from waste water
or sewage, it is well to get the press cakes as dry as possible, and it may not be
worth while to utilize the liquids (which might be done by hydraulic pressure); in
such cases they may be dried off by heat.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Browne in the Great Seal Patent Office on the 31st
August 1878.
ALEXANDER BROWNE, of the Firm of Browne and Company, Patent Agents, of
5, Southampton Buildings, Holborn, in the County of Middlesex. "IMPROVEMENTS
RELATING TO THE TREATMENT OF VARIOUS MATERIALS BY THE EMPLOYMENT OF
FILTER PRESSES." (A communication from abroad by George Bourdon, of Paris,
France.)
Filter presses are used in the manufacture of sugar, but have heretofore been
little applied in chemical manufactures, mainly because of inconveniences arising
from the construction of the presses.
According to this Invention filter presses are applied to various substances, such
as washing waters from wool and other materials, in sugar refineries, for treatment
of sewage and glairy liquids, in soap making, for phosphate precipitates and
muriatic acid, in the treatment of wine lees.
The liquids may be either acid or alcaline, and limpid or glairy. The filter press
must be modified accordingly.
For acid liquids the filter press is coated with paraffine where in contact with
the liquid; it may be put on hot, but it is better, in order to form a long lasting
glaze, that the part should be heated to a high temperature.
The acid products may be limpid. In that case the cloths should be steeped in a
preserving substance, and capable of making the apertures in the material as fine as
possible.

page_text: If the liquids are glairy they must be mixed with paper pulp or other analogous
material on which the liquid has only a feeble influence. In this case more
ordinary cloths may be employed than for limpid liquids.
For alcaline liquids it is desirable to use cloths that are not affected by them;
for this purpose the threads in the cloth are of metallic wire or enclosed in india-
rubber or other suitable material. Ordinary pumps are not suitable, but pumps
with bellows of india-rubber or other acid-resisting material are suitable, or wooden
pumps.
For most of the above materials the liquid has to be filtered repeatedly. For
this purpose
the central conduit in the press is done away with, and the liquid runs
from the first chamber into the following between the two cloths, and so on as often
as desired.
In certain cases the press cake is of little value, the liquid alone being valuable;
thus for instance in treating caustic soda and potash, the charcoal in refineries,
wine lees, and aniline dyes, in such cases the cakes should be as dry as possible,
and for this purpose, according to this Invention, a pump working under a pressure
of at least 20 atmospheres is employed. All the liquid that escapes is collected
during the undoing of the filtering frames.
In other cases where the cake is the valuable part (for instance, in phosphate
precipitates in the treatment of wash waters from wool and sewage) the cake in as
dry a state as possible is put in a hydraulic press for expressing the liquid re-
maining. The filter press represents in that case only a first stage in the
process.
In the treatment of wine lees, contact of the same with iron must be avoided. In
the construction of the filter press only oak or tinned copper must be exposed to it.
If muriatic acid is used in the tinning it will rapidly become detached by the
influence of the wine. The bags or cloths should be of cotton with close meshes,
and for a complete filtration should be coated with paste or good lees. Only with
these precautions a filter press can be employed for wine.
Waters resulting from washing of wool are first treated with acids as weak as
possible. They take up the alcaline salts, and free the fatty matters which are
mixed with inert matters, such as carbon or sawdust. The whole is well stirred,
and by a pump or extractor conveyed to a filter press, which ought to be coated
internally with paraffin. The liquids running off contain salts with alcaline base.
The greasy matters form cakes, which are taken away, and the useful parts ex-
tracted in the usual manner. As to the limpid liquids they are used again for washing
fresh wool. This water is treated as before described, and brought to the filter press
for extraction of fatty and insoluble matters, and for rendering limpid a liquid
charged still more with salts of alcaline base. This liquid may thus be methodically
'charged, and it will always be right to operate the solution of the matters contained
in the wool to saturation. A solution is finally obtained sufficiently rich for
evaporation, leaving as residues salts of potash or soda.
To avoid the decomposition of greasy matter into sulphates not having n
saponificant character and of less value than the oxydes of potash or soda, which
exist in a state of combination in the salts resulting from the washing, the precipita-
tion is preferably done by oxyde of calcium or any other salt capable of being
substituted for saponificant oxydes of potassium or sodium.
Each passage through the filter press gives a limpid liquid more caustic, and
which is treated by evaporation when the water has become sufficiently rich in
potash, or quite deprived of the brick ashes which are retained in the press cakes.
These very alcaline liquids should be filtered through tissues not attacked by the
alcalies. For this purpose cloths are employed as above described, or, better still,
made of wire gauze covered or not by a textile, not woven, material, such as jute,
that withstands the action of the alcalies.
The system of methodical charging of liquids in the treatment of the wool-wash
waters is almost only possible by the employment of the filter press, for decantation

page_text: will not do, all the liquid will not be obtained, and these will be a sensible loss. If
on the contrary the ordinary filtering process is used it takes much time to be
commercially possible, and the insoluble matters will always retain a quantity of
liquid. The filtering under pressure corrects these evils. It is in a general way
applicable to all chemical products for giving a result equivalent to that described
with regard to wool-washing water.
Whenever a liquid, by reason of re-action, contains insoluble matter and soluble
salts, the filter press may be employed for treating, so as to separate the liquids,
which are rendered limpid. These limpid liquids may serve afresh as solvents,
instead of the water first employed, and when the re-action takes place they will
contain insoluble matters of the nature of the preceding ones and a very strong
proportion of soluble salts, which are separated afresh by the filter press. The liquid
obtained will thus always be very limpid, and contain an increasing quantity of
soluble salts.
With certain materials, such as phosphate precipitates or manure from waste
water or sewage, it is well to get the press cakes as dry as possible, and it may not
be worth while to utilize the liquids (which might be done by hydraulic pressure); in
such cases they may be dried off by heat.
And baving thus described and ascertained the nature of this Invention I declare
that I claim,
Firstly. The application of the filter press in the above-named trades as one of
the important elements of manufacture, as set forth.
Secondly. The modes and means, substantially as described, for rendering such
application of the filter press possible.
Thirdly. The adaptation of the filter press for the new manufactures, sub-
stantially as set forth.
Fourthly. The mode of treatment of wool-washing water or other equivalents in
which the filter press permits of charging the water of soluble salts, sepa ating
successively precipitates and the insoluble matters, and in general the application
of the filter press in the chemical trades for charging the liquid of soluble salts,
all substantially as set forth.
Fifthly. The employment of the filter press in these various trades, and also in
filtration by pressure, for the purpose of producing a primary press cake which can
be compressed in the hydraulic press, and solidified by desiccation, as set forth.
In witness whereof, I, the said Alexander Browne, have hereunto set my
hand and seal, this Thirty-first day of August, in the year of our Lord One
thousand eight hundred and seventy-eight.
A BROWND