AN IMPROVEMENT IN BLEACHING AND DISINTEGRATING THE FIBRES OF STRAW BOILED IN CAUSTIC SODA
Year: 1880

page_text: LETTERS PATENT to Friedrich Carl Glaser, of Berlin, in the Kingdom of
Prussia, and Empire of Germany, Engineer and Patent Agent, for an Invention
of "AN IMPROVEMENT IN BLEACHING AND DISINTEGRATING THE FIBRES OF
STRAW BOILED IN CAUSTIC SODA." A communication from Julius Kauffmann,
of Croellwitz, near Halle, Prussia, Germany.
PROVISIONAL SPECIFICATION left by the said Friedrich Carl Glaser at
the Office of the Commissioners of Patents on the 3rd March 1880.
$$
FRIEDRICH CARL GLASER, of Berlin, in the Kingdom of Prussia and Empire of
Germany, Engineer and Patent Agent. AN IMPROVEMENT IN BLEACHING AND
DISINTEGRATING THE FIBRES OF STRAW BOILED IN CAUSTIC SODA." A commu-
nication from Julius Kauffmann, of Croellwitz, near Halle, Prussia, Germany.
"
This Invention relates to a process of bleaching and of baring or stripping and
separating or disintegrating by the aid of gaseous chlorine the fibres of straw
boiled in caustic soda.
The straw of rye, wheat, oats, and barley, after being separated from weeds by a
slight or superficial picking, is cut by means of a chopping knife or cutter into
pieces, of say, from 1/, to %, of an inch (1 to 1, "cents.") in length. The straw
thus cut up is then introduced into a rotary boiler, and boiled for, say, four hours,
according to the ordinary process, under a pressure of from 4 to 41, atmospheres,
and under the action of, say, 29 lbs. (13 "kilogrammes") of caustic soda at
71 degrees, and of, say, 48 lbs. (22 "kilogrammes "), calcined soda at 90 degrees
rendered caustic, for-every 220-lbs. (100 kilos) of straw. After the boiling the
lye water is drawn off, and the boiled straw freed from the dirty lye by a double
introduction and drawing off of cold water. It is then carried to the washing
engine where it is washed for, say, an hour, by means of a washing cylinder or
drum, the sieve or sifter of which has about 60 openings to the square inch.
The washed straw is then dried by a centrifugal force hydro-extractor, in such a
manner that it will contain about 70 per cent. of water, which is necessary for the
action of the gaseous chlorine.
To attain this object so as to work upon a large scale and obtain not very

page_text: close or solid cakes of straw, it is necessary that the sieve or sifter of the hydro-
extractor through which the water is expelled, should not have more than fifty
holes to the square inch.
"
The cakes of straw thus formed are then exposed to the action of the gaseous
chlorine in leaden chambers of the ordinary kind, in which they are placed by
layers upon hurdles or open shelves, so as to avoid a compact juxta position. If the
gaseous chlorine is produced by chlorhydric-acid, there will be used for every
220 lbs. (100 kilogrammes") of unboiled straw, the quantity of chlorine obtained
from, say, 50 lbs. ("23 kilos.") of chlorbydric acid at 22 degrees "Beaumé," and of
a corresponding quantity of pyrolusite containing 70 per cent. of peroxide of
manganese. If the pyrolusite is of inferior quality containing a large quantity of
iron, capable of absorbing chlorhydric acid for the formation of oxide and chloride of
iron the dose of this substance must be increased.
After this bleaching operation, the acids which have become transformed must
be eliminated by means of washing in a washing engine. Then if by the bleaching
with the gas, a complete reduction of the fibres has not been produced, this may be
obtained mechanically by the aid of well known special machines and apparatus,
and either before or subsequent to the after bleaching, in which there is used for
220 lbs. ("100 kilos.") of straw, about 4 lbs. ("2 kilos.") of chloride of lime at
35 degrees.
Explanation. As pine wood or fir is chemically freed from its coloring principle
and transformed into fibres as well as into cellulose, the object of the intense action
of the gaseous chlorine is to destroy the mucilage of the straw as well as the
incrusting matters which have not been destroyed by the boiling with caustic soda,
and consequently to strip or expose and open the fibres.
To obtain a long and supple fibre from straw, it is very important to limit the
mechanical working to the action of a cutting and crushing surface.
The above described process distinguished by the production of a long elastic
and extremely white fibre, which permits a greater utilisation in the paper,
prevents the sizing in the presses during the work at the paper machine, and does
not give to the paper a brittle appearance.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Friedrich Carl Glaser in the Great Seal Patent Office on the 4th
August 1880.
FRIEDRICH CARL GLASER, of Berlin, in the Kingdom of Prussia and Empire of
Germany, Engineer and Patent Agent. "AN IMPROVEMENT IN BLEACHING AND
DISINTEGRATING THE FIBRES OF STRAW BOILED IN CAUSTIC SODA." A commu-
nication from Julius Kauffmann, of Croellwitz, near Halle, Prussia, Germany.
This Invention relates to a process of bleaching and of baring or stripping and
separating or disintegrating by the aid of gaseous chlorine or chloric gas the fibres
of straw boiled in caustic soda.
The straw of rye, wheat, oats, and barley, after being separated from weeds by a
slight or superficial picking, is cut by means of a chopping knife or cutter into
pieces, of say, from / to % of an inch (1 to 14 "cents.") in length. The straw
thus cut up is then introduced into a rotary boiler and boiled for, say, four hours,
according to the ordinary process, under a pressure of from 4 to 4 atmospheres,
and under the action of, say, 29 lbs. ("13 kilogrammes") of caustic soda at
71 degrees, and of, say, 48 lbs. ("22 kilogrammes") of calcined soda at 90 degrees,
rendered caustic for every 220 lbs. ("100 kilogrammes") of straw. After the
boiling the lye water is drawn off, and the boiled straw freed from the dirty lye
by a double introduction and drawing off of cold water. It is then carried to the
washing engine, where it is washed for, say, an hour, by means of a washing
cylinder or drum, the sieve or sifter of which has about 60 openings to the square
inch.
The washed straw is then dried by a centrifugal force, bydro-extractor, in such a
manner, that it will contain about 70 per cent. of water, which is necessary for the
action of the gaseous chlorine.
To attain this object so as to work upon a large scale and obtain not very solid
or close cakes of straw, it is necessary that the sieve or sifter of the hydro-extractor
through which the water is expelled, should not have more than fifty holes to the
square inch,
The cakes of straw thus formed are then exposed to the action of the gaseous
chlorine in leaden chambers of the ordinary kind, in which they are placed by
layers upon hurdles or open shelves, so as to avoid a compact juxtaposition. If
the gaseous chlorine is produced by chlorhydric acid, there will be used for every
220 lbs. ("100 kilogrammes") of unboiled straw, the quantity of chlorine obtained
from, say, 501/, lbs. ("23 kilogrammes") of chlorhydric acid at 22 degrees "Beaumé,"
and of a corresponding quantity of pyrolusite containing 70 per cent. of peroxide
of manganese. If the pyrolusite is of inferior quality containing a large quantity
of iron capable of absorbing chlorhydric acid for the formation of oxide and
chloride of iron, the dose of this substance must be increased.
After this bleaching operation, the acids which have become transformed must
be eliminated by means of washing in a washing-engine. Then, if by the bleaching
with the gas, a complete reduction of the fibres has not been produced, this may be
obtained mechanically by the aid of well known special machines and apparatus,
and either before or subsequent to the after bleaching, in which-there-is-used for
220 lbs. (100 kilogrammes-") of straw, about 44 lbs. (" 2 kilogrammes") of chloride
of lime at 35 degrees.
°
Explanation. As pine wood or fir is chemically freed from its coloring principle
and transformed into fibres, as well as into cellulose, the object of the intense action
of the gaseous chlorine is to destroy the mucilage of the straw, as well as the
incrusting matters which have not been destroyed by the boiling with caustic soda,
and consequently to strip or expose and open the fibres.

page_text: To obtain a long and supple fibre from straw it is very important to limit the
mechanical working to the action of a cutting and crushing surface.
The above described process is distinguished by the production of a long elastic
and extremely white fibre, which is deprived of all incrustating component parts,
and in its chemical composition gives clean cellulose.
Having now described and ascertained the nature of the Invention communicated
to me as aforesaid, and in what manner the same is or may be performed, I would
have it understood that I do not limit myself to the precise details hereinbefore set
forth, as they may be modified while retaining the essential parts of this improved
process, and that
I claim as secured to me by the hereinbefore in part recited Letters Patent,-
The use of free gaseous chlorine or chloric gas for the production of chemically
clean bleached cellulose, from mixtures of straw fibres boiled in caustic soda,
substantially as herein before described.
In witness whereof, I, the said Friedrich Carl Glaser, have hereunto set my
hand and seal, this Ninth day of July, in the year of our Lord One
thousand eight hundred and eighty.