Improvements in or connected with the Process of Bleaching Fibrous Materials in the Manufacture of Paper.
Year: 1894

page_text: Date of Application, 10th Feb., 1894
Complete Specification Left, 10th Nov., 1894-Accepted, 15th Dec., 1894
*PROVISIONAL SPECIFICATION.
Improvements in or connected with the Process of Bleaching
Fibrous Materials in the Manufacture of Paper.
We, BENJAMIN CAWTHORN, of Ford Paper Works, Hylton R.S.O. Foreman
Paper Maker, and JAMES PORTEUS CORNETT, of Claxheugh near Sunderland,
Paper Mill Manager, both in the County of Durham, do hereby declare the nature
of this invention to be as follows:-
:-
This invention relates to improvements in or connected with the process of
bleaching fibrous materials in the manufacture of paper.
As at present most generally practiced the bleaching is, effected in the potching
engine the roll in the latter being raised from the plate to the required distance
after the fibres have been sufficiently reduced thereby. In this arrangement the
roll is used firstly to beat or reduce the fibrous material and afterwards to more
or less continue this action but principally to propel and agitate the pulp in the
vat while being bleached. Much power is thus uselessly spent in rotating the roll
for the purpose of effecting the uniform bleaching of the material.
In our improved process of bleaching we propose to use by preference though
we may vary the form of such engine such an apparatus as is described in
J. P. Cornett's Patent Specification No. 14,191 A.D. 1893 wherein the fibres
after being treated in the boilers are at once sufficiently reduced for bleaching
purposes. From such or an equivalent breaking or beating device we propose
to take the stuff after duly straining the water therefrom in a cone save-all or
washer direct to a bleaching. battery and to there bleach it as hereinafter
foreshadowed.
Thus we propose to construct for example one or a pair or more of chests fitted
with internal agitating devices with valve-controlled outlets at or towards their
bases. Into such chests the requisite quantity of bleaching liquor may be
measured and the fibre may be introduced till the chests are more or less full
the agitating arms or devices being kept in motion if necessary during the filling.
These chests we propose to connect by pipes and pumping or blowing apparatus
with a battery of bleaching tanks of any suitable size shape or capacities each of
the latter being provided with valve-controlled basal or other outlets communi-
cating with mains or other piping leading to a pumping or blowing plant adapted
to deliver through suitable conduits into a trough or other conduit or series of such
arranged over or near and adapted to empty itself or themselves at will into any
one or more of the bleaching tanks constituting the battery.
Thus the partially bleached stuff (both liquor and fibre) in one chest may be
extracted therefrom and transferred as above described to or over the top of or
into No. 1 tank this being effected at the requisite temperature by the introduction
of a steam jet or otherwise to assist the action of the bleach. Another chest may
meantime have been similarly prepared and when this is ready the contents of the
first or other tank may be transferred as above foreshadowed to or over the top of
or into the next tank while the tank just emptied may be in like manner filled
from either a chest or a recently filled tank. Suitable intervals may intervene
between the several operations.
There will thus be a more or less continuous filling and emptying of the chests
accompanied by a more or less continuous agitation mixing and transmission of
the stuff from chests to tanks and from tanks to tanks till the process is complete
and the stuff is prepared for the supply chest for the press-pâte or next process.

page_text: It will be observed that in the improved process described there will necessarily
be constant exposures of fresh surfaces of fibrous material for the bleaching agent
to act upon as the stuff is successively agitated in its course from the mixing or
filling chest to the last tank of the series and this as compared with any previous
process where liquor has been caused to percolate through a series of tanks more
or less choked with fibrous material and in which the bleach has little opportunity
of thorough commixture with the fibres is a novel and important economical
consideration.
Dated this 9th day of February 1894
A. CRAWHALL CHAPMAN,
3, St. Nicholas Buildings, Newcastle-on-Tyne, Patent Agent.
COMPLETE SPECIFICATION.
Improvements in or connected with the Process of Bleaching
Fibrous Materials in the Manufacture of Paper.
We, BENJAMIN CAWTHORN, of Ford Paper Works, Hylton R.S.O., Foreman
Paper Maker, and JAMES PORTEUS CORNETT, of Claxheugh, near Sunderland,
Paper Mill Manager, both in the County of Durham, 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 :-
This invention relates to improvements in or connected with the process of
bleaching fibrous materials in the manufacture of paper.
As at present most generally practiced the bleaching is effected in the potching
engine the roll in the latter being raised from the plate to the required distance
after the fibres have been sufficiently reduced thereby. In this arrangement the
roll is used firstly to beat or reduce the fibrous material and afterwards to more or
less continue this action but principally to propel and agitate the pulp in the vat
while being bleached.
Much power is thus uselessly spent in rotating the roll for the purpose of
effecting the uniform bleaching of the material.
In our improved process of bleaching we propose to use by preference though
we may vary the form of such engine such an apparatus as is described in
J. P. Cornett's Patent Specification No. 14,191, A.D. 1893 wherein the fibres
after being treated in the boilers are at once sufficiently reduced for bleaching
purposes. From such or an eqvivalent breaking or beating device we propose to
take the stuff after duly straining the water therefrom in a cone save-all or washer
direct to a bleaching battery and there to bleach it as bereinafter foreshadowed.
Thus we propose to construct for example one or a pair or more of chests fitted
with internal agitating devices with valve-controlled outlets at or towards their
bases.
Into such chests the requisite quantity of bleaching liquor may be measured and
the fibre may be introduced till the chests are more or less full the agitating arms
or devices being kept in motion if necessary during the filling.
These chests we propose to connect by pipes and pumping or blowing apparatus
with a battery of bleaching tanks of any suitable size shape or capacities each of
the latter being provided with valve-controlled basal or other outlets communi-
cating with mains or other piping leading to a pumping or blowing plant adapted
to deliver through suitable conduits into a trough or other conduit or series of such
arranged over or near and adapted to empty itself or themselves at will into any
one or more of the bleaching tanks constituting the battery.
Thus the partially bleached stuff (both liquor and fibre) in one chest may be
extracted therefrom and transferred as above described to or over the top of or
into No. 1 tank this being effected at the requisite temperature by the introduction

page_text: of a steam jet or otherwise to assist the action of the bleach. Another chest may
meantime have been similarly prepared and when this is ready the contents of the
first or other tank may be transferred as above foreshadowed to or over the top
of or into the next tank while the tank just emptied may be in like manner filled
from either a chest or a recently filled tank.
Suitable intervals may intervene between the several operations.
There will thus be a more or less continuous filling and emptying of the chests
accompanied by a more or less continuous agitation, mixing and transmission of
the stuff from chests to tanks and from tanks to tanks till the process is complete
and the stuff is prepared for the supply chest for the press-pâte or next.
process.
66
"
It will be observed that in the improved process described there will necessarily
be constant exposures of fresh surfaces of fibrous material for the bleaching agent
to act upon as the stuff is successively agitated in. its course from the mixing or
filling chest to the last tank of the series and this as compared with any previous
process where liquor has been caused to percolate through a series of tanks
more or less choked with fibrous material and in which the bleach has little
opportunity of thorough commixture with the fibres is a novel and important
economical consideration.
We will fully describe our invention with reference to the accompanying
drawings in which Figure 1 shows in side elevation and Figure 2 in plan view
apparatus constructed to bleach fibrous materials as hereinafter described and in.
the following description like marks of reference designate like parts.
Referring to the drawings A is a cone save-all or washer for straining the
water from the broken fibres after they have been treated in the boilers and in:
such a breaking or beating engine or the equivalent thereof as is hereinabove
alluded to. B is a trough arranged with means in any convenient manner so that
the material may issue therefrom either to a vat or chest such as is shown at C
and C¹ or instead of chests or vats of this particular form bleaching vats as now
used or any other suitable measuring and mixing vessel may be employed. 3 is an
overhead shaft with pinions 4 gearing with mitre wheels 5 adapted to drive
spindles 6 in chests C, C¹.
These spindles are fitted with arms 7 to agitate the material in the chests.
The bases of the latter are furnished with openings and valves 8 and pipes 9
leading to a centrifugal or other pumping plant 10 the delivery pipe 11 from
which is carried upwards to deliver into tank T. The base of this tank is
similarly provided with an opening and valve 12 and in like manner tanks T¹ T'
TT are each provided with a basal opening and a valve 12 and a branch pipe
communicating with a main pipe M which leads to another centrifugal or other
equivalent pumping plant P.
The latter is arranged to deliver up pipe N to a trough or conduit () and the
liquid material so delivered can thence be run into any one of the tanks T T¹
T T T as desired suitable plugs or valves being arranged in the trough over
each tank for this purpose.
In the practical bleaching of the fibrous material according to the apparatus
shown in the drawings, firstly the requisite quantity of bleaching liquor will be
measured into one of the chests C C¹.
Suppose chest C to be soused then the fibre may be introduced till the chest is
full during and after which filling process the agitating arms 7 will be kept in
motion for a certain time so as to aid in partially bleaching the material. Valve 8
of chest C will then be opened and pump 10 will extract the contents from chest C
and deliver them into tank T. As soon as tank T is full its valve 12 may be
opened and pump P will extract through pipe M the contents of tank T and
deliver them via conduit O into say tank T.
Meantime chest C' may have been similarly prepared for bleaching and when
tank T is empty its valve 12 will be closed and the contents of chest C¹ may then
be transferred by pump 10 to tank T. The contents of tank T' may then be

page_text: transferred in like manner by pump P to tanks T2 T3 T4 and as each of these
tanks is again afterwards emptied in succession they may be refilled by transferring
or pumping the contents of the previous or another tank thereinto in the manner
described.
Though we have described and shown a certain number and design of chests
and tanks and manner of working the same the plant and mode of working same
may be varied to suit circumstances but in all cases there must be a sufficient
number of tanks to enable the pumping process to act on the partially bleached
stuff for a sufficient length of time to thoroughly bleach the fibres and after this is
done the pump may finally deliver the bleached stuff to the "press pâte" or to a
supply chest as found convenient.
We are aware that "steep-bleaching" in vessels either with or without agitating
devices is old and we are also aware that "steep-bleaching" in a series of vessels
has been described but in the latter the liquor only has been transferred from
vessel to vessel and in no case has the bleaching been effected on the improved
principle as hereinabove shown.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. The improved process of bleaching fibrous materials in the manufacture of
paper consisting in firstly exposing the broken fibres to the action of the bleaching
liquor in a vat or vessel or chest provided with agitating arms to effect a partial
bleaching of the fibre the intermediate and final bleaching of the fibres being
effected by the intermittent agitation and exposure of fresh surfaces of fibre to the
bleach while the partially bleached stuff (both liquor and fibre) is being with-
drawn and transferred by suitable pumping or blowing plant from vat or chest to
tank and thence from tank to tank in succession till the operation is complete
substantially as herein set forth.
2. The combination of apparatus forming the improved bleaching battery
arranged designed and adapted to perform the function of bleaching fibrous
materials in stages substantially as described and illustrated in the drawings
hereto annexed.
Dated this 9th day of November 1894.
A. CRAWHALL CHAPMAN,
3, St. Nicholas Buildings, Newcastle-on-Tyne, Patent Agent.