AN IMPROVED MANUFACTURE OF SOLVENTS FOR TREATING WOOD AND OTHER VEGETABLE FIBRE FOR THE PRODUCTION OF PULP
Year: 1881

page_text: LETTERS PATENT to David Otto Francke, of Korndal Mölndal, in the
Kingdom of Sweden, for an Invention of "AN IMPROVED MANUFACTURE OF
SOLVENTS FOR TREATING WOOD AND OTHER VEGETABLE FIBRE FOR THE
PRODUCTION OF PULP."
"AN
PROVISIONAL SPECIFICATION left by the said David Otto Francke at the
Office of the Commissioners of Patents on the 17th December 1881.
DAVID OTTO FRANCKE, of Korndal Mölndal, in the Kingdom of Sweden.
IMPROVED MANUFACTURE OF SOLVENTS FOR TREATING WOOD AND OTHER
VEGETABLE FIBRE FOR THE PRODUCTION OF PULP."
In a Provisional Specification filed by me on the 11th October 1881, No. 4419,
I described a method of treating fragments of wood or other vegetable fibre for the
production of pulp. My present Invention relates to the manufacture of solvents
suitable for such treatment. The solvents which I employ are acid sulphites of
alkalies or alkaline earths, that is to say, solutions of such sulphites along with
excess of sulphurous acid. As one of the cheapest materials available, I prefer to
employ lime, of which I produce the acid sulphite in the following manner :-
I charge a tower or vertical column with fragments of limestone which may be.
more or less pure, and which may contain other alkaline earths, such as magnesia.
On this limestone I cause a shower of water to descend while sulphurous acid
fumes produced by burning sulphur or sulphides, such as pyrites, are caused to pass
through the tower. The liquid which collects at the bottom of the tower is the
acid sulphite required, which I find most suitable when it has a strength of 4°
to 5° Beaumé. Instead of alkaline earths the soluble alkalies, soda or potassa, may
be employed as bases of the solutions. For this purpose I charge the tower or
column with inert porous materials, such as coke or fraginents of brick or porous
stone, and while the sulphurous acid fumes are passed through it I cause a shower
to descend consisting of a solution of caustic soda or potassa having a strength
of 1° to 2° Beaumé. Instead of employing caustic alkalies, their carbonates may
be used as above described in solutions proportionally stronger.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said David Otto Francke in the Great Seal Patent Office on the 4th
April 1882.
"AN
DAVID OTTO FRANCKE, of Korndal Mölndal, in the Kingdom of Sweden.
IMPROVED MANUFACTURE OF SOLVENTS FOR TREATING WOOD AND OTHER
VEGETABLE FIBRE FOR THE PRODUCTION OF PULP."
In the Specification to Letters Patent granted to me on the 11th October 1881,
No. 4419, I described a method of treating fragments of wood or other vegetable
fibre for the production of pulp. My present Invention relates to the manufacture
of solvents suitable for such treatment. The solvents which I employ are acid
sulphites of alkalies or alkaline earths, that is to say, solutions of such sulphites
along with excess of sulphurous acid. As one of the cheapest materials available,
I prefer to employ lime, of which I produce the acid sulphite in the following
manner Icharge a tower or vertical column with fragments of limestone which may
be more or less pure, and which may contain other alkaline earths, such as magnesia.
On this limestone I cause a shower of water to descend, while sulphurous acid
fumes produced by burning sulphur or sulphides, such as pyrites, are caused to
pass through the tower. The liquid which collects at the bottom of the tower
is the acid sulphite required, which I find most suitable when it has a strength
of 4° to 5° Beaumé. Instead of alkaline earths the soluble alkalies, soda or potassa,
may be employed as bases of the solutions. For this purpose I charge the tower
or column with inert porous materials, such as coke or fragments of brick or porous
stone or loose twigs, and while the sulphurous acid fumes are passed through it I
cause a shower to descend consisting of a solution of caustic soda or potassa having
a strength of 1° to 2° Beaumé. Instead of employing caustic alkalies their
carbonates may be used as above described in solutions proportionally stronger.
Having thus described the nature of my Invention and in what manner the
same is to be performed, I would have it understood that I make no claim to the
process of treating wood or other vegetable fibre with sulphites of alkalies or
alkaline carths for the production of pulp, in the manner described in my
Specification No. 4419, of 1881, above referred to, but I claim,-
The manufacture of solvents for treating wood and other vegetable fibre for the
production of pulp, substantially as herein described.
In witness whereof, I, the said David Otto Francke, have hereunto set my
hand and seal, this Thirty-first day of March, in the year of our Lord One
thousand eight hundred and eighty two.
DAVID OTTO FRANCKE. (L.S.)