DISCLAIMER AND MEMORANDUM OF ALTERATIONNOW
Year: 1881

page_text: DISCLAIMER AND MEMORANDUM OF ALTERATION proposed to be
entered by the aforesaid Carl Daniel Ekman pursuant to the Statutes in.that
case made and provided
WHEREAS since the filing of the Specification of the aforesaid Letters Patent
I the said Carl Daniel Ekman have ascertained that the Invention for which I
applied for Letters Patent is described and claimed in the Specification in terms
that are too wide and which comprise more than was new at the date of the said
Letters Patent. I am therefore desirous of disclaiming such parts of the said
Specification and of altering or amending the claims therein in the manner herein=
after set forth.
NOW KNOW YE that I. the said Carl Daniel Ekman by and with the leave of
Her Majesty's Solicitor General for the reasons aforesaid do alter and amend the
said Specification in manner following that is to say
:
I strike out the words "also in" which occur on line 13 of page 3 of the Queen's
Printer's Copy of the said Specification published at the Great Seal Patent Office
in One thousand eight hundred and eighty two I also strike out the whole of the
lines 15 to 18 inclusive of the said page 3-I also strike out the words." and the
resulting solution of an amber color which occur on the line 49 of page 4-I
also strike out the whole of the lines 50 to 55 inclusive of the said page 4-I also
strike out the words "Instead of using caustic soda chemicals are employed.which
have a far" which occur on line 8 of page 5-I also strike out the whole of the
line 9 of the said page 5 I also strike out the words "much cheaper" which

page_text: "
occur on line 10 of the said page 5 I also strike out the words "and the incrusting
matter obtained is in" which occur on line 16 of the said page 5-I also strike out
the whole of the lines 17 and 18 of the said page 5-I also strike out the whole of
the lines 29 to 35 inclusive I also strike out the word First" which occurs on
line 41 of the said page 5 I also strike out the word "herein before" which occurs
on line 42 of the said page 5 I also strike out the whole of the line 43 and the
words "off gas and steam during the operation which occur on line 44 of the said
page 5 and after the word "conditions" which occurs on line 42 of the said page 5
I insert the words "as to blowing off gas and steam substantially
و"
And in order that the effect of the Disclaimer and Memorandum of Alteration
as aforesaid may be clearly understood-I annex hereto a Copy of the said
Specification as it will appear when so altered and amended the preamble and
testing clause being omitted
My Invention of "An improved method of treating wood in order to obtain
fibre suitable for paper making and other purposes" has for its object the pro-
duction from wood of a fibre or fibres suitable for paper making and for other
purposes
And my Invention consists in boiling wood under pressure with a solution
containing sulphurous acid and magnesia in the proportions and under the
conditions hereinafter, stated blowing off gas and steam during the process of
boiling
It will be convenient to describe the process as applied to Swedish white fir of
good quality and fine grain previously freed from bark and knots and cut into
pieces of suitable for and size (say half to three quarters of an inch long) and sub-
sequently crushed between rollers so as to render the wood easily permeable by the
liquid solution in order to produce fibre of the best quality for paper making, but
the mode of preparation may be varied-White fir and trees of the same order are
especially suitable as they give long and strong fibre very clean and similar in its
properties for paper making to that of flax and this kind of wood is comparatively
cheap and abundant in many Countries.
The suitableness of other kinds of wood for the purpose depends much upon the
length and properties of its fibre as well as on the facility or difficulty found in
dissolving the incrusting matter so that in the selection of wood much will depend
on the purpose for which the pulp is required but in general that wood which is
very resinous is avoided because of the difficulty found in dissolving the incrusting
matter sufficiently to obtain good cellulose..
The raw-material- of wood- is- selected with- more-or-less-care according to the
purpose for which it is required but when a superior quality of pulp has to be
produced all exceptionally resinous and hard pieces of wood as well as those damaged
by rot are to be thrown out.
Wood in small pieces thus prepared (and if necessary duly sorted) is put into a
jacketted boiler lined with lead or a suitable compound thereof or other suitable
material and mounted on trunnions for the convenience of filling and emptying
The boiler may be vertical and cylindrical of about four feet diameter inside and
twelve feet between the two ends. The wood is put into the boiler until it is
within about two feet and the solution to within about four inches of the top end
of the boiler but the quantity of wood is limited only by the condition that it
should be completely covered with the solution during the whole of the boiling
process.
In the preparation of the boiling liquid or solution the proportions between the
sulphurous acid and the magnesia found to be most advantageous are about two
equivalents of the former to one of the latter (or approximately those which go to
form the salt commonly called bisulphate of magnesia.
The strength of the solution is such that it contains approximately one and
four tenths per cent of magnesia and four and four tenths per cent of sulphurous
acid.
The boiler is filled with this solution to such an extent that while the wood is

page_text: perfectly covered by it there is yet sufficient room left in the upper part to form a
steam space The wood is prevented from rising above the liquid during the boiling
by the pressure thereon of a perforated leaden plate After the boiler has been
charged with wood and the solution under the conditions stated a cover is bolted
on and made tight by ordinary means.
Steam of from ten to fifteen pounds pressure on the square inch is now passed
gradually into the jacket of the boiler the condensed water returning into the
generating boiler in the usual way-When the pressure in the boiler itself (not the
jacket) begins to exceed five pounds to the square inch a valve placed at the highest
part of the boiler for the purpose is opened so that a small quantity of gas and
steam escapes The pressure of steam in the jacket is gradually increased as the
steam pressure is seen to rise in the boiler itself and it is preferred that the pressure
in the jacket should not exceed that in the boiler by more than thirty pounds per
square inch.
As the pressure in the boiler increases more gas and steam are allowed to escape
from the before named valve the object being to prevent the burning or discoloura-
tion of the wood during the operation For boilers of the size above referred to the
boiling is or may be conducted so that after two hours the pressure in the inner
boiler is ten pounds and this is increased twenty pounds per hour for the two
following hours in the next hour fifteen pounds and in each of the two following
hours ten pounds When the pressure has reached eighty five or ninety pounds per
square inch or thereabouts the boiler is allowed to remain at that pressure for from
one to three hours the completion of the operation being indicated by the smell.-
In case of any burning or discolouration taking place (which is easily detected by
the odour emitted or by the colour of the liquid) steam is blown off the mass
turned out of the boiler and water thrown on it-But if there be no sign of burning
the mass may remain in the boiler for some time after steam has been blown off
The cover is then taken off the boiler turned on its trunnions and the fibre strained
off from the liquor-The fibre is washed and beaten in the usual manner and the
liquor may be treated in any suitable way in order to obtain a gummy matter
which for some purposes may be used as a substitute for ordinary dextrine also to
obtain other useful products or for the recovery of the chemicals.
If it be desired to obtain a fibre less approaching pure cellulose by dissolving
a smaller part of the incrusting matter of the wood a weaker solution and lower
pressure may be used
The solution employed may also be varied to a considerable extent it being
understood as a general rule that if the salt be more basic than that above
described the incrusting matter will be less completely dissolved and if more acid
(and waste is to be avoided) there is more liability to burning
The pressure above indicated may in some cases be varied
The completion of the boiling operation has in the foregoing description been
fixed at about eighty five to ninety pounds pressure because good results may be
relied upon within this limit and for practical purposes increase of pressure beyond
this point may be attended with disadvantage economically but I do not confine
myself to this limit because good results have been obtained at a pressure up to
one hundred and ten pounds and even above this
The fibre resulting from the above treatment of the wood is suitable for good
ordinary printing paper and may be made suitable for superior papers by means
of treatment with bleaching powder
The Invention can be easily applied to other kinds of wood besides the white fir
described by modifying the process according to the product required and the wood
used the quality of the fibre obtained depending upon the suitableness of the wood
and the other above named conditions
If the wood is very resinous (although its original fibre may be good) the
resulting material may only be useful for the coarser kinds of paper and similar
materials owing to the difficulty of removing the incrusting matter
The peculiar character of the Invention will be understood by considering the

page_text: "
advantages possessed by it over the usual method in which caustic soda is. employed
In boiling with caustic soda the separation of the fibre from the incrusting matter
depends as is well known on such matter being rendered soluble by oxidation. but
it is impossible to prevent the fibres themselves from being also oxidized to. some
extent thereby weakening and partially destroying them and diminishing the
quantity of pulp yielded by the wood On the other hand in the preparation of
pulp according to my Invention no oxidation of the fibre can occur when the
operation is properly conducted
Another advantage is that the boiling can be done at about half the pressure
required by the usual method which is of great importance in practice besides that
the fibre is less liable to be weakened in the process A third advantage is that by
this method fibre can be prepared which without any further chemical treatment is
sufficiently white to be used for ordinary kinds of paper and, is capable of
After a
supplying a strong good paper without admixture of other fibre
subsequent treatment with bleaching powder it is made suitable for the manufacture
of all the finer kinds of paper This fibre much resembles linen in its physical
and chemical properties for paper making and is therefore a very valuable material
for this purpose
And lastly cellulose of good quality can be prepared at a comparatively low cost
by the process herein before described
Having thus described the nature of the said Invention and in what manner
the same is to be performed I hereby declare that what I claim as of my said
Invention is
The boiling of wood under pressure with a solution containing sulphurous acid
and magnesia in the proportions and under the conditions and in the manner as
hereinbefore described
:
In witness whereof I the said Carl Daniel Ekman have hereunto set my
hand and seal this eleventh day of August in the year of our Lord One
thousand eight hundred and eighty two.
i
The application for leave to file this Disclaimer and Memorandum of Alteration
having been advertized in accordance with my direction, and Objections to the
same having been heard and disposed of by me,
I hereby grant my Fiat giving leave to the above named Carl Daniel Ekman
to file in the Great Seal Patent, Office with the Specification to which the same
relates the above written Disclaimer and Memorandum of Alteration:
Dated this 15th day of August 1882
TT
TARKER HERSCHELL
Solicitor General:

page_text: LETTERS PATENT to Carl Daniel Ekman, of Sweden, but now of 57, Old
Broad Street, in the City of London, for an Invention of "AN IMPROVED
METHOD OF TREATING WOOD IN ORDER TO OBTAIN FIBRE SUITABLE FOR
PAPER-MAKING AND FOR OTHER PURPOSES."
PROVISIONAL SPECIFICATION left by the said Carl Daniel Ekman at the
Office of the Commissioners of Patents on the 13th July 1881.
CARL DANIEL EKMAN, of Sweden, but now of 571, Old Broad Street, in the City
of London. "AN IMPROVED METHOD OF TREATING WOOD IN ORDER TO OBTAIN
FIBRE SUITABLE FOR PAPER MAKING AND FOR OTHER PURPOSES."
My Invention has for its object the production from wood of a fibre or fibres
suitable for paper making and for other purposes.
And my Invention consists in boiling wood under pressure with a solution
containing sulphurous acid and magnesia in the proportions, and under the
conditions hereinafter stated; also in blowing off gas and steam during the process
of boiling.
Potash and soda may also be employed for the purpose, but, I prefer to use
magnesia as being more economical, and having chemical properties which
render it peculiarly suitable, and therefore the Invention will be described
with especial reference to the use of magnesia, but the substitution of soda
either wholly or in part would involve the necessity of only slight modifications in
the process.
It will be convenient to describe the process as applied to Swedish white fir of
good quality and fine grain previously freed from bark and knots and cut into
suitable pieces and subsequently crushed, so as to render it easily permeable by the
liquid solution in order to produce fibre of the best quality for paper making.
Wood in small pieces thus prepared is put into a jacketted boiler lined with
lead or a suitable compound thereof, and mounted on trunnions for the convenience
of filling and emptying. The quantity of wood put into the boiler is limited only
by the condition that it should be completely covered with the solution during the
whole boiling process.

page_text: In the preparation of the boiling liquid or solution the proportions between the
sulphurous acid and the magnesia found to be most advantageous are about two
equivalents of the former to one of the latter (or approximately those which go to
form the salt commonly called bisulphite of magnesia).
The strength of the solution is such that it contains approximately one and four
tenths per cent. of magnesia and four and four tenths per cent. of sulphurous acid.
The boiler is filled with this solution to such an extent that while the wood is
perfectly covered by it there is yet sufficient room left in the upper part to form a
steam space.
The wood is prevented from rising above the liquid during the
boiling by the pressure thereon of a perforated leaden plate. The boiler after
being charged with wood and the solution under the conditions stated, a cover is
bolted on and made tight by ordinary means.
Steam of from ten to fifteen pounds pressure on the square inch is now passed
gradually into the jacket of the boiler, the condensed water returning into the
generating boiler in the usual way. When the pressure in the boiler itself (not
the jacket) begins to exceed five pounds to the square inch, a valve placed in the
highest part of the boiler for the purpose is opened so that a small quantity of gas
and steam escapes. The pressure of steam in the jacket is gradually increased as
the steam pressure is seen to rise in the boiler itself, and it is preferred that the
pressure in the jacket should not exceed that in the boiler by more than thirty
pounds per square inch.
As the pressure in the boiler increases more gas and steam are allowed to escape
from the before named valve, tho object being to prevent the burning of the wood
during the operation. When the pressure has reached eighty five pounds per
square inch or thereabouts the boiler is allowed to remain at that pressure for from
one to three hours, the completion of the operation being indicated by the smell.
In case of any burning taking place (which is easily detected by the odour emitted)
steam is blown off, the mass turned out of the boiler and water thrown on it.
But if there be no sign of burning the mass may remain in the boiler for some
time after steam has been blown off. The cover is then taken off, the boiler turned
on its trunnions, and the fibre strained off from the liquor. The fibre is washed
and beaten in the usual manner, and the liquor may be treated in any suitable
manner in order to obtain a gummy matter, which for some purposes may be used
as a substitute for ordinary dextrine; also other useful products or for the recovery
of the chemicals.
If it be desired to obtain a fibre less approaching pure cellulose by dissolving
a smaller part of the incrusting matter of the wood a weaker solution.and lower
pressure may be used.
The pressure above indicated may in some cases be varied. The fibre resulting
from the above treatment of the wood is suitable for good ordinary printing paper,
and may be made suitable for superior papers by means of treatment with bleaching
powder. And the resulting solution of an amber color contains a large quantity
of gummy matter resembling ordinary dextrine and other incrusting and soluble
matters which the wood contained, and which may be made more or less available
.for commercial purposes.
The resulting fibre may be suitable for coarser kinds of paper, mill boards,
papier maché, and similar materials, even if the separation of the cellulose from
the incrusting and other matter has not been so complete, as above described.
The Invention can be easily applied to other kinds of wood besides the white
fir described by modifying the process according to the product required, the
quality of the fibre obtained depending upon the suitableness of the wood.and.the
other above named conditions.
If the wood is very resinous (although its original fibre may be good), the
resulting material will only be useful for the coarser kinds of paper and similar
materials owing to the difficulty of removing the incrusting matter.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Carl Daniel Ekman in the Great Seal Patent Office on the
11th January 1882.
CARL DANIEL EKMAN, of Sweden, but now of 57, Old Broad Street, in the City
of London. "AN IMPROVED METHOD OF TREATING WOOD IN ORDER TO OBTAIN
FIBRE SUITABLE FOR PAPER MAKING AND OTHER PURPOSES."
My Invention of "An Improved Method of Treating Wood in order to obtain
Fibre Suitable for Paper Making and other Purposes," has for its object the
production from wood of a fibre or fibres suitable for paper making and for other
purposes.
And my Invention consists in boiling wood under pressure with a solution
containing sulphurous acid and magnesia in the proportions and under the
conditions hereinafter stated; also in blowing off gas and steam during the process
of boiling.
Potash and soda may also be employed for the purpose, but I prefer to use
magnesia as being more economical and having chemical properties which render
it peculiarly suitable, and therefore the Invention will be described with especial
reference to the use of magnesia.
It will be convenient to describe the process as applied to Swedish white fir of
good quality and fine grain previously freed from bark and knots and cut into
pieces of suitable form and size (say, of half to three quarters of an inch long), and
subsequently crushed between rollers so as to render the wood easily permeable by
the liquid solution in order to produce fibre of the best quality for paper making;
but the mode of preparation may be varied. White fir and trees of the same
order are especially suitable, as they give long and strong fibre, very clean, and
similar in its properties for paper making to that of flax; and this kind of wood
is comparatively cheap and abundant in many countries.
The suitableness of other kinds of wood for the purpose depends much upon the
length and properties of its fibre, as well as on the facility or difficulty found in
dissolving the incrusting matter, so that in the selection of wood much will depend
on the purpose for which the pulp is required. But in general that wood which
is very resinous is avoided, because of the difficulty found in dissolving the
incrusting matter sufficiently to obtain good cellulose.
The raw material of wood is selected with more or less care according to the
purpose for which it is required, but when a superior quality of pulp has to be
produced, all exceptionally resinous and hard pieces of wood as well as those
damaged by rot are to be thrown out.
Wood in small pieces thus prepared (and if necessary duly sorted), is put into a
jacketted boiler, lined with lead or a suitable compound thereof or other suitable
material, and mounted on trunnions for the convenience of filling and emptying. The
boiler may be vertical and cylindrical, of about four feet diameter inside and twelve
feet between the two ends. The wood is put into the boiler until it is within about
two feet, and the solution to within about four inches of the top end of the boiler,
but the quantity of wood is limited only by the condition that it should be
completely covered with the solution during the whole boiling process.
In the preparation of the boiling liquid or solution the proportions between the
sulphurous acid and the magnesia found to be most advantageous are about two
equivalents of the former to one of the latter (or approximately those which go to
form the salt commonly called bisulphite of magnesia).
The strength of the solution is such that it contains approximately one and four
tenths per cent. of magnesia and four and four tenths per cent. of sulphurous
acid.
The boiler is filled with this solution to such an extent that while the wood is
perfectly covered by it, there is yet sufficient room left in the upper part to form a

page_text: steam space. The wood is prevented from rising above the liquid during the
boiling by the pressure thereon of a perforated leaden plate. After the boiler has
been charged with wood and the solution under the conditions stated a cover is
bolted on and made tight by ordinary means.
Steam of from ten to fifteen pounds pressure on the square inch is now passed
gradually into the jacket of the boiler, the condensed water returning into the
generating boiler in the usual way. When the pressure in the boiler itself (not
the jacket) begins to exceed five pounds to the square inch, a valve placed at the
highest part of the boiler for the purpose is opened, so that a small quantity of gas
and steam escapes. The pressure of steam in the jacket is gradually increased as
the steam pressure is seen to rise in the boiler itself, and it is preferred that the
pressure in the jacket should not exceed that in the boiler by more than thirty
pounds per square inch.
As the pressure in the boiler increases, more gas and steam are allowed to escape
from the before named valve, the object being to prevent the burning or dis-
colouration of the wood during the operation. For boilers of the size above
referred to, the boiling is or may be conducted so that after two hours the pressure
in the inner boiler is ten pounds, and this is increased twenty pounds per hour for
the two following hours, in the next hour fifteen pounds, and in each of the two
following hours ten pounds. When the pressure has reached eighty five or ninety
pounds per square inch or thereabouts the boiler is allowed to remain at that
pressure for from one to three hours, the completion of the operation being
indicated by the smell. In case of any burning or discolouration taking place
(which is easily detected by the odour emitted or by the colour of the liquid)
steam is blown off, the mass turned out of the boiler, and water thrown on it. But
if there be no sign of burning, the mass may remain in the boiler for some time
after steam has been blown off. The cover is then taken off, the boiler turned on
its trunnions, and the fibre strained off from the liquor. The fibre is washed and
beaten in the usual manner, and the liquor may be treated in any suitable way in
order to obtain a gummy matter, which for some purposes may be used as a
substitute for ordinary dextrine, also to obtain other useful products, or for the
recovery of the chemicals.
If it be desired to obtain a fibre less approaching pure cellulose, by dissolving a
smaller part of the incrusting matter of the wood, a weaker solution and lower
pressure-may-be-used. -
-
'
The solution employed may also be varied to a considerable extent, it being
understood as a general rule that if the salt be more basic than that above described
the incrusting matter will be less completely dissolved, and if more acid (and waste
is to be avoided) there is more liability to burning.
The pressure above indicated may in some cases be varied.
The completion of the boiling operation has in the foregoing description been
fixed at about eighty five to ninety pounds pressure, because good results may be
relied upon within this limit, and for practical purposes increase of pressure beyond
this point may be attended with disadvantage economically; but I do not confine
myself to this limit, because good results have been obtained at a pressure up to
one hundred and ten pounds, and even above this.
The fibre resulting from the above treatment of the wood is suitable for good
ordinary printing paper, and may be made suitable for superior papers by means of
treatment with bleaching powder; and the resulting solution, of an amber color,
contains a large quantity of guinmy matter, resembling ordinary dextrine, and other
incrusting and soluble matters which the wood contained, and which may be made
more or less available for commercial purposes.
The resulting fibre may suitable for coarser kinds of paper, mill boards, papier
maché, and similar materials, even if the separation of the cellulose from the
incrusting and other matter has not been so complete as above described.
The Invention can be easily applied to other kinds of wood besides the white fir
described by modifying the process according to the product required and the wood

page_text: used, the quality of the fibre obtained depending upon the suitableness of the wood
and the other. above named conditions.
If the wood is very resinous (although its original fibre may be good) the resulting
material may only be useful for the coarser kinds of paper and similar materials,
owing to the difficulty of the removing the incrusting matter.
The peculiar character of the Invention will be better understood by considering
the advantages possessed by it over the usual method in which caustic soda is
employed. Instead of using caustic soda, chemicals are employed which have a far
less damaging effect on the fibres, and which, especially when magnesia is used, are
much cheaper. In boiling with caustic soda, the separation of the fibre from the
incrusting matter depends, as is well known, on such matter being rendered soluble
by oxidation, but it is impossible to prevent the fibres themselves from being also
oxidized to some extent, thereby weakening and partially destroying them, and
diminishing the quantity of pulp yielded by the wood. On the other hand, in the
preparation of pulp according to my Invention, no oxidation of the fibre can occur
when the operation is properly conducted, and the incrusting matter obtained is in
the form of a gummy matter of commercial value, instead of being converted, as by
the old method, into worthless products of the humus type.
Another advantage is that the boiling can be done at about half the pressure
required by the usual method, which is of great importance in practice, besides that
the fibre is less liable to be weakened in the process. A third advantage is, that by
this method fibre can be prepared which without any further chemical treatment is
sufficiently white to be used for ordinary kinds of paper, and is capable of supplying
a strong good paper without admixture of other fibre. After a subsequent treatment
with bleaching powder it is made suitable for the manufacture of all the finer
kinds of paper.
This fibre much resembles linen in its physical and chemical
properties for paper making, and is therefore a very valuable material for this
purpose.
A fourth advantage is that the solution which remains after boiling contains a
gum like substance, which at a small cost can be made to serve as a substitute for
dextrine for many purposes, and thereby produce economy in the manufacture.
Some portion also of the chemicals used in the solution may be recovered. A further
advantage consists in avoiding the injurious effect on vegetation and on animal
life produced, as is well known, by spent soda lye resulting from the ordinary method
or process.
And, lastly, cellulose of good quality can be prepared at a comparatively low cost
by the process hereinbefore described.
Having thus described the nature of the said Invention, and in what manner
the same is to be performed, I hereby declare that what I claim as of my said
Invention is,
First. The boiling of wood under pressure with a solution containing sulphurous
acid and magnesia in the proportions and under the conditions herein before
described; and, secondly, the use of a valve or equivalent arrangement for blowing
off gas and steam during the operation, as herein before described.
In witness whereof, I, the said Carl Daniel Ekman, have hereunto set my
hand and seal, this Tenth day of January, in the year of our Lord One
thousand eight hundred and eighty two
Witness,
WILLIAM SPENCE,
8, Quality Court,
Chancery Lane.
C. D. EKMAN. (LS.)