Improved Method of and Means for Protecting Apparatus used in the Manufacture of Sulphite Cellulose.
Year: 1888

page_text: Date of Application, 10th Dec., 1888
Complete Specification Left. 7th Sept., 1889-Accepted. 7th Dec.. 1889
PROVISIONAL SPECIFICATION.
Improved Method of and Means for Protecting Apparatus used in the
Manufacture of Sulphite Cellulose.
We, Dr. Jur FERDINAND SALOMON, of 59 Mohrenstrasse, Berlin, and HERMANN
BRÜNGGER, of Cunnersdorf, Reg. Bez. Liegnitz, Factory Manager, do hereby declare
the nature of this invention to be as follows:-
The present applicants have proposed to prevent the destructive action of sulphite
lye upon boiling apparatus used in the manufacture of cellulose by the so called
sulphite process by causing the formation of a protective scale from the sulphite lye
upon the parts exposed to such destructive action. According to the present
invention the protective scale may be produced by means of solutions of other salts
than those in the lye.
With this object there is introduced into the boiling vessels a solution of salts such
that on being separated from the solution they will form a coating or scale (similar
to boiler scale) which is not dissolved by the liquid employed in the manufacture of
cellulose.
Of the salts suitable for this purpose there may be mentioned for instance sulphate
of lime, sulphate of baryta, and sulphate of strontian.
:-
This invention may be carried into practice as follows:-
.
When rotary boilers are employed, all the parts which are to be protected by a
coating precipitated or deposited from the lye itself, are made with double walls in
order to enable said parts to be heated by means of a heating medium introduced
into the intermediate space thus produced.
In order to be able to let off the steam or gases generated in the boiler during
heating, it is desirable to provide a valve and discharge pipe where convenient.
The intermediate spaces between the double walls of the manholes and other
unions are put in communication with those between the double walls of the
boiler by connecting pipes or passages and are supplied with heating steam by a
pipe from a suitable source.
Rotary motion may be imparted to the boiler. by means of rollers and has for its
object to enable all the parts of the boiler shell and the manholes and other unions
which are to be protected, to be brought into contact with and heated by the steam
during the boiling process.
Rotating boilers with single walls may be provided externally with a covering of
masonry which contains openings corresponding to the manholes and other unions
and preferably also with a discharge pipe and valve for discharging any vapours or
gases that may be formed.
The heating of the boiler shell is effected by means of hot gases such as products
of combustion or hot air, which are introduced into the intermediate space between
the boiler and masonry, so that the boiler shell is heated to the requisite
temperature.
The heating of the shell is continued during the duration of the boiling process
and serves at the same time as the heating agent for effecting the boiling process
itself.
Non rotating (fixed) boilers with single walls are provided in a similar manner
with a covering of masonry.
The boiler provided with a pipe leading to a closed vessel situated within the
covering of masonry.
A discharge pipe and discharge valve may be provided where convenient.
When non rotating or fixed boilers with single walls are employed, these boilers
must be completely filled with the salt or gypsum solution in order to be able to
produce the scale on the entire surface of the boiler.

page_text: The closed vessel bereinabove referred to serves to receive the liquid which
overflows as a result of the increase in volume of the contents of the boiler conse-
quent on the rise in temperature.
This vessel and the pipe connecting it with the boiler are preferably provided
with valves which are so loaded that the pressure remains in the same somewhat
lower than in the boiler proper. The heating of the boiler shell and the heating of
'the subsequent contents of the boiler is effected as in the rotary boilers with-simple
walls.
Before using the boiler for the manufacture of cellulose it is filled for example
with a saturated gypsum solution sufficiently to enable the entire inner
surface of the boiler to be wetted or brought into contact with the liquid
during, the subsequent rotation of the boiler shell. Fixed boilers are preferably
filled full.
'
The boiler is then closed and the contents of the boiler are heated so that all the
parts of the boiler that are to be provided with a protective scale are brought into
contact with steam or hot gases up to boiling point.
During the heating of the boiler and until the scale is completely formed, the
boiler if capable of rotation may be rotated slowly.
When the solution in the boiler has reached boiling point valves arranged on the
manhole covers or elsewhere, are opened, from time to time to allow the steam
generated in the boiler to escape; in consequence the solution becomes more
concentrated and gypsum is precipitated and is deposited upon the inner surface of
the boiler in the form of a hard, durable, protective scale which is insoluble in
sulphite lye.
5.
When
gypsum ceases to be precipitated from the solution, and if the scale be still too
thin, the process is repeated, or fresh gypsum is added until the desired thickness of
the scale is obtained.
The formation of a protective scale in boilers without steam jacket is effected in
the same manner as in those with steam jacket. When the scale is quite formed the
apparatus is then put to its proper use.
This process and the apparatus described is applicable not only to the manufacture
of cellulose from wood, but also to the manufacture of cellulose both from wood as
also from all other suitable fibrous substances.
Thus the sulphite cellulose" hereinabove mentioned must be taken to mean a
cellulose which is produced either from wood or from any other suitable fibrous
substance.
In the production of the protective scale by heating the walls of the boiler, and in
the subsequent introduction of the sulphite lye, the boiling apparatus is preferably
provided with a valve through which the gases evolved during the formation of the
scale may be removed or allowed to escape.
Dated this 10th day of December 1888...
FERDINAND SALOMON,
Per L. W.
HERMANN BRÜNGGER,
Per L. W.
COMPLETE SPECIFICATION.
Improved Method of and Means for Protecting Apparatus used in the
Manufacture of Sulphite Cellulose.
We, Dr. Jur FERDINAND SALOMON, of 59, Mohrenstrasse, Berlin, and HERMANN
BRUNGGER, Cunnersdorf, Reg. Bez. Liegnitz, Factory Manager, 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
:-
In the specification of an application for Letters Patent No. 13396 of 1888, we
have described an invention for a method of preventing the destructive action of
sulphite lye upon boiling apparatus used. in the manufacture of cellulose by the so

page_text: called "sulphite process," by depositing a protective coating or film on the internal
surface of the boiling vessel by heating from the outside the bare internally exposed
iron or steel wall of the said vessel and then admitting sulphite solution or lye into
contact with the so heated internal surface of the said vessel and exposing it to the
action of heat from without in such a manner as to cause the formation of a pro-
tective scale from the sulphite lye upon the parts exposed to such destructive action.
Now according to the present invention a protective scale is produced by means of
solutions of salts other than those in the lye. With this object there is introduced
into the vessels used for boiling purposes, a solution of a salt or salts such that on
being separated from the solution it or they will form a coating or scale (similar
to boiler scale) which will not be dissolved by the liquid employed in the manufac-
ture of cellulose.
Of the salts suitable for this purpose there may be mentioned for instance sulphate
of lime, sulphites of baryta or strontia.
This invention may be carried into practice as follows:-
When rotary boilers are employed all the parts including the manhole and other
unions which are to be protected by a coating precipitated or deposited from the lye
itself, are made with double walls B as shewn for example in Fig. 1 of the accom-
panying drawings in order to enable the said parts to be heated by means of à
heating medium introduced into the intermediate space thus produced.
In order to be able to let off the steam or gases generated in the boiler A
during heating, it is desirable to provide a valve L and discharge pipe K where
convenient.
The intermediate spaces between the double walls of the manholes C and other
unions are placed in communication with the intermediate spaces between the double
walls of the boiler by connecting pipes or passages D and are supplied with heating
steam by a pipe F from a suitable source.
Rotary motion may be imparted to the boiler by means of rollers E and has for its
object to enable all the parts of the boiler shell and the manhole and other unions which
are to be protected, to be brought into contact with and heated by the steam during
the boiling process.
Rotating boilers with single walls may be provided externally with a covering of
masonry as shown for example in Fig. 2 of the accompanying drawings furnished.
with openings G and H corresponding to the manhole unions C and preferably also
with a discharge pipe K and valve L as shown, for discharging any vapours or gases
that may be formed. The heating of the boiler shell is effected by means of hot
gases, such as products of combustion or hot air, which are introduced into the
intermediate spaces between the boiler and masonry so that the boiler shell is heated to
the requisite temperature.
The heating of the shell is continued during the duration of the boiling process
and serves at the same time as the heating agent for effecting the boiling process
itself.
Non-rotating or fixed boilers with single walls are provided in a similar
manner with a covering of masonry as shown for example in Fig. 3.
Such boilers must be completely filled with the solution of gypsum or other
salt employed in order to be able to produce the scale over the entire
surface of the boiler. The boiler A is provided with a pipe leading to a
closed vessel J situated within the covering of masonry as shown. This closed
vessel serves to receive the liquid which overflows as a result of the increase in
volume of the contents of the boiler consequent on the rise in temperature. The
closed vessel J and the pipe connecting it with the boiler, are preferably provided
with valves V V which are so loaded that the pressure in the closed vessel shall be
somewhat lower than in the boiler proper. The heating of the boiler shell and the
subsequent heating of the contents of the boiler is effected as in the rotary boilers
with a single wall. The boiler may be provided with a discharge pipe and discharge
valve where convenient.
.
Before using a rotary boiler for the manufacture of cellulose it is charged, for

page_text: example with a saturated gypsum solution, anfficiently to enable the entire inner
surface of the boiler to be wetted or brought into contact with the liquid during the
subsequent rotation of the boiler shell. Before charging the boiler with the salt
solation the boiler may be preheated or not. Fixed boilers are preferably filled up.
The boiler is then closed, and the contents of the boiler are heated so that all the
parts of the boiler that are to be provided with a protective scale, are brought into
contact with steam or hot gases up to boiling point.
During the heating of the boiler and until the scale is completely formed, the
boiler if capable of rotation may be rotated slowly.
:
When the solution in the boiler has reached boiling point, the valve L arranged on
the manhole covers or other suitable place, are opened from time to time to allow the
steam generated in the boiler to escape; in consequence the solution becomes more
concentrated and gypsum is precipitated and is deposited upon the inner surface of
the boiler in the form of a hard, durable, protective scale which is insoluble in
sulphite lye.
When gypsum ceases to be precipitated from the solution, and if the scale be still
too thin, the process is repeated, or fresh gypsum is added until the desired thickness
of the scale is obtained.
The formation of a protective scale in boilers without steam jacket is effected in a
similar manner to that described for boilers having a steam jacket. When the
scale is quite formed the apparatus is then put to its proper use.
Boiling apparatus having a protective coating or film deposited in the manner
herein before described is applicable not only to the manufacture of cellulose from
wood, but also to the manufacture of cellulose from all other suitable fibrous
substances.
Thus the "sulphite cellulose" hereinabove mentioned must be taken to mean a
cellulose which is produced either from wood or from any other suitable fibrous
substance or substances.
In the production of the protective scale by heating the walls of the boiler, and in
the subsequent introduction of the sulphite lye, as described in our said former
specification, the boiling apparatus so protected may advantageously be provided with
a valve through which the gases evolved during the formation of the scale may be
removed or allowed to escape.
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 we claim is :-
1. The herein described method of producing a protective scale or coating on the
bare internal wall or surface of a steel or iron boiler employed in the manufacture of
sulphite cellulose as hereinabove defined, which consists in introducing into the
boiler, being preheated or not, a solution of gypsum or other salt or salts which,
when heated, will produce on the said internal wall or surface a deposit such as will
not be attacked by heated sulphite lye, and afterwards heating the boiler until the
formation of the desired scale or coating is completed.
2. For the purpose of allowing escape of gases or vapours during the production
of a protective scale or coating whether according to the Patent No. 13396 of 1888 or
according to claim 1 of this specification, providing the boiling apparatus with a valve
as set forth.
3. For the boiling of sulphite substances the use of a boiler or vessel constructed of
iron or steel and having on its internal surface a protective coating or scale produced
from a substance (such as a solution of gypsum or other salt or salts) other than
the sulphite solution to be treated.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.