Improvements in the Manufacture and Bleaching of Wood and other Pulps and Apparatus for that Purpose.
Year: 1889

page_text: Date of Application, 1st Feb., 1889
Complete Specification Leit, 29th Oct., 1889-Accepted, 30th Nov., 1889
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture and Bleaching of Wood and other
Pulps and Apparatus for that Purpose.
I, Charles RamSEY, of Now Wortley, Leeds, in the County of York, Chemist, do
hereby declare the nature of this invention to be as follows:-
My invention relates to the manufacture and bleaching of wood and other pulps
for papor making and such like purposes, and to apparatus for carrying out the
process.
For this purpose, I introduce the wood or other suitable vegetable material in
chips, fragments or small pieces, into a vertical cylindrical vessel which has a
perforated floor and under that a compartment from which a central vertical pipe
ascends nearly to the top of the vessel, this pipe having within it near its lower end
an injector nozzle. I charge the bottom compartiment of the vessel with saturated
lime water, and then by admitting steam to the injector nozzle I cause this liquid
to flow up the central pipe and to break into spray against the top of the vessel so
that it becomes distributed over the material in the vessel. The liquid percolating
through the material returns to the bottom compartment, is again caused to flow up
the pipe and so on continuously for 6 or 8 hours, until it is ascertained by sampling
that the material has undergone sufficient treatment.
The steam supply is then cut off, the liquid is withdrawn, and water is passed
through the material to wash it. The washing water having been withdrawn, tho
bottom compartment is charged with a solution of hypochlorite of magnesia which is
caused to circulate through the material by means of the injector jet, for about the
same timo as the lime water.
The material is then ready for being beaten up into pulp, but in many cases it is
desirable to have it whitened by bleaching, which I effect in a separate vessel pro-
vided with a revolving agitator. The pulp, having been fed into this vessel, is kept
agitated while a stronger solution of hypochlorite of magnesia is caused to circulate
through it by means of a rotary or other pump, for several hours.
The pulp being then washed is ready for use either directly for paper making or
for being pressed and dried for transport.
The bleaching above described may be applied not only to pulp prepared as I have
described but also to pulp prepared by other treatment.
Dated this 1st day of February 1889.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Manufacture and Bleaching of Wood and other
Pulps and Apparatus for that Purpose.
I CHARLES RAMSEY of New Wortley Leeds, in the County of York Chemist
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 :-
My invention relates to a process and apparatus for the manufacture and bleaching
of wood, straw rag and other pulps for paper making and such like purposes. The
process naturally divides itself into two parts or operations, the one being the
preparation of the crude pulp, the other the bleaching of the crude pulp. Usually
the crude pulp is first prepared and this is afterwards bleached.

page_text: In many cases, however, fibres, chips rags &c. adapted for pulp making may be
bleached in the first instance, and the bleached material may be afterwards made into
pulp. I shall describe these two operations separately, and in order that they may
be better understood I illustrate by the accompanying drawings an arrangement of
apparatus whereby the two operations can be conveniently carried on either separately
or consecutively.
Fig. 1 is a plan and Fig. 2 a vertical section of a pulping boiler. Fig. 3 is a plan
of two bleaching vessels one of them shewn in section and Fig. 4 is a vertical section
of one of them."
Referring first to Figs. 1 and 2, A is a boiler which is preferably mounted on
trunnions A so that it can be turned obliquely or inverted to give convenience for
repairs. In the centre of the boiler there is a vertical pipe A² open at the top and
terininating at the bottom in a perforated cone A. Within the pipe A2 is an inner
pipe A which is open at the top and the bottom and within its lower end there is a
jet nozzle A for steam. Near the bottom of the vessel A is a perforated floor A
and nearly close to the botton is a perforated filter plate A'. The vessel A is provided
with water gauges A³, a manhole A°, safety valve and pressure gauge A" and a dis-
charge outlet with valve A". A steam pipe B with valve leads to the jet nozzle A³,
and a blow off pipe B' with valve leads from the bottom of the boiler A. Above
the top of A are situated two or more tanks (conaining the chemical substances
which I employ these tanks communicating with the bottom of A. by a pipo ("
having a branch from each tank provided with a stopcock or valve.
I operate with this apparatus for making pulp in the following manner.
Having charged the vessel A up to nearly the top of the pipe A' with the wood
or other vegetable material in chips, fragments or small pieces, I let saturated lime
water flow from one of the tanks into the bottom of A till it rises a little above the
perforated floor Aº. I then admit steam to the jet nozzle A and thereby cause the
fime water to flow up the central pipe to impinge against the cover or against a
spreading plate under the cover, by which the current of lime water is broken and
distributed over the pulp material.
The liquid percolating through the interstices of the material returns to the bottom
compartment, is again caused to flow up the pipe and so on continuously for 6 or
8 hours until it is ascertained by sampling that the material has undergone sufficient
treatment. The steam supply is then cut off the liquid is run off by the pipe B' and,
if necessary, water can be passed through the material to wash it.
The washing water having been withdrawn, the bottom compartment is charged with
a solution of hypochlorite of magnesia formed by mixing sulphate of magnesia and
chloride of lime. These may be used in various proportions with water according to
the character of the material operated on. I find a good proportion for most
ordinary pulp materials to be a solution of the strength of about 3° Beaume, con-
sisting of about 70 per cent. of sulphate of magnesia to about 30 per cent. of chloride
of lime. This solution is caused to circulate by means of the steam jet for about
6 to 8 hours. The hypochlorite solution having been run off, the material may again
be washed with water and it can then be discharged by the outlet A" ready for being
beaten up into pulp. In most cases it is desirable to bleach the pulp material prepared as
above described, and for this purpose it may be run direct into either of the bleaching
vessels shewn by Figs. 3 and 4.
Each of those vessels D is of cylindrical form having within it a revolving
agitator D¹.
At one side of the vessel is formed a pocket having in front of it a perforated
plate D and having at its bottom a valve D³ which can be opened by a lever D'
mounted on the cover.
A tank E contains a strong solution of hypochlorite of magnesia which in this
case may have a strength of 1° to 2° Beaume, and may consist of equal parts sulphate
of magnesia and chloride of lime. This tank E communicates with the valve
opening D³ and through a rotary pump E³ and pipe E³ with either of the vessels D.

page_text: The pulp in D is kept agitated for several hours by the revolution of the agitator D'
while the hypochlorite of magnesia is kept circulating through it by means of the
pump E. The bleached pulp is then run off by the pipe Do.
Although I have described the bleaching in D as being applied to the crude pulp
delivered from A, pulps otherwise prepared, such as those prepared by treatment with
soda sulphate of soda, or sulphite of lime may be similarly bleached. Also fibres
fine chips, rags and the like can be bleached as described before being made
into pulp.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. The process for manufacturing bleached pulp by causing to circulate through
the pulp material, first lime water, then a solution of sulphate of magnesia and
chloride of lime, and afterwards agitating the material thus treated while a solution of
sulphate of magnesia and chloride of lime is caused to circulate through it substantially
as described.
2. The process for manufacturing unbleached pulp by causing to circulate through
the pulp material first lime water then a solution of sulphate of magnesia and chloride
of lime, substantially as described.
3. The process for bleaching pulp or pulp material by agitating it while a solution
of sulphate of magnesia and chloride of lime is caused to circulate through the
material, substantially as described.
4. For the manufacture and bleaching of pulp the combined apparatus consisting of
the pulp boiler and connections described with reference to Figs. 1 and 2, and the
bleaching vessels and connections described with reference to Figs. 3 and 4.
5. For bleaching pulp the apparatus described with reference to Figs. 3 and 4.
Dated this 29th day of October 1889.
ABEL & IMRAY,
Agents for the Applicant.