IMPROVEMENTS IN THE MANUFACTURE OF FILTERING PAPER
Year: 1881

page_text: LETTERS PATENT to Samuel Henry Johnson, F.C.S., of Engineering Works,
Stratford, in the County of Essex, for an Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF FILTERING PAPER."
PROVISIONAL SPECIFICATION left by the said Samuel Henry Johnson at
the Office of the Commissioners of Patents on the 3rd November 1881.
SAMUEL HENRY JOHNSON, F.C.S., of Engineering Works, Stratford, in the
County of Essex. "IMPROVEMENTS IN THE MANUFACTURE OF FILTERING
PAPER."
This Invention has for its object the manufacture of filtering paper by mixing
carbon with paper pulp and forming it into sheets. For this purpose animal or
vegetable carbon may be employed, but the former being more active is usually to
be preferred.
The animal charcoal may be prepared either by calcining bones, blood, or other
animal substances, and in the case of bone charcoal it will be rendered much more
active and suitable for the purposes of this Invention by dissolving and washing
out from it the phosphate of lime by means of hydrochloric acid. In the case of
carbon derived from blood its activity is much increased by ignition of the blood
with carbonate of potash.
These methods of preparation of the carbon employed are known, and do not
form part of my Invention.
To obtain the best results such quantity of the carbon should be added to the
paper pulp, as it will admit without unduly injuring its tenacity for the purpose
it is intended to be employed.
The sheets of paper so prepared are not sized, and in all respects are prepared
as is customary in the preparation of filtering paper.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Samuel Henry Johnson in the Great Seal Patent Office on the
2nd May 1882.
SAMUEL HENRY JOHNSON, F.C.S., of Engineering Works, Stratford, in the
County of Essex. "IMPROVEMENTS IN THE MANUFACTURE OF FILTERING
PAPER."
This Invention has for its object the manufacture of filtering paper by mixing
carbon with paper pulp and forming it into sheets.
For this purpose animal or vegetable carbon may be employed, but the former
being more active is usually to be preferred.
The animal charcoal may be prepared either by calcining bones, blood, or other
animal substances, and in the case of bone charcoal it will be rendered much more
active and suitable for the purposes of this Invention by dissolving and washing
out from it the phosphate of lime by means of hydrochloric acid. In the case of
carbon derived from blood its activity much increased by ignition of the blood
with carbonate of potash.
These methods of preparation of the carbon employed are known, and do not
form part of my Invention.
To obtain the best results such quantity of the carbon should be added to the
paper pulp, as it will admit without unduly injuring its tenacity for the purpose it
is intended to be employed.
The sheets of paper so prepared are not sized, and in all respects are prepared
as is customary in the preparation of filtering paper.
The carbon which is most active for my purpose is that produced by drying
down blood with carbonate of potash and igniting it in closed retorts.
The finished paper should contain from 5 to 20 per cent. of the carbon by
weight; such quantities can be introduced into the pulp without unduly weakening
the paper.
The carbon can be added after the pulp has been thoroughly washed in the
beater engine.
The best pulp for the purpose is that with long fibre, as it retains a larger
proportion of the carbon.
The usual process for the manufacture of filtering paper is in other respects
followed.
The paper may be made in various thicknesses as at present.
What I claim is the manufacture of filtering paper by mixing carbon with paper
pulp and forming it into sheets, substantially as described.
In witness whereof, I, the said Samuel Henry Johnson, have hereunto set my
hand and seal, this First day of May, in the year of our Lord One thousand
eight hundred and eighty two.
CAMIL
JAUNSON 101