Improvements in the Preparation of Wood Pulp for the Manufacture of Paper, Cloth, Cordage, or any other Textile Fabric.
Year: 1889

page_text: Date of Application, 12th June, 1889-Accepted, 19th Oct., 1889
COMPLETE SPECIFICATION.
[Communicated from abroad by HUGO PATAKY and WILHELM PATAKY, both of
Koniggratzer Strasse, 41, Berlin, Germany, Civil Engineers.]
Improvements in the Preparation of Wood Pulp for the Manufacture
of Paper, Cloth, Cordage, or any other Textile Fabric.
I, FREDERICK JOHN CHEESBROUGH, of 15, Water Street, Liverpool, in the County
of Lancaster, Patent Agent, do hereby declare the nature of my said invention and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
The object of the invention is to reduce wood into stock with the least possible
manual labour and the least possible quantity of alkali, and it consists essentially in
crushing green wood between rollers, and subjecting the said green wood while being
crushed, to a stream of water preferably in the form of jets, so that the bark and fluid
constituents, such as glucose, gum, albumen etcetera shall be crushed and washed out
of the wood leaving but a small quantity of the objectionable constituents, which may
be readily removed by boiling the crushed wood in a weak alkaline solution,
substantially as hereinafter more particularly explained.
In all processes with which I am familiar, for the manufacture of wood pulp, old or
dried wood is used, and in order to abstract the constituents of the wood which would
render the pulp unsuitable for the manufacture of paper it is necessary to cut the wood
into small pieces and boil it for a long time at a very high temperature and under
great pressure in a very strong alkaline solution.
It has been discovered that freshly-cut or green wood in which the sap is still fresh
may be prepared into stock suitable for the manufacture of paper, cloth, cordage, or
any other textile fabric without the necessity of cutting the wood into small pieces, or
subjecting it to a lengthy process of boiling in a strong alkali solution under great
pressure, and at a high temperature such as I have stated is necessary in the processes
prior to my invention.
In my process I take freshly-cut or green wood cut into as long lengths as can be
comfortably handled, and pass the said lengths of wood between any suitable kind of
crushing rollers, the said rollers being arranged and adjusted so as to thoroughly break
down the cellular structure of the wood, which breaking down will effectually press
out nearly all the fluid constituents of the wood, water being employed for the
purpose of thoroughly washing the said crushed material as it leaves the crushing
rollers.
I prefer to arrange a series of jets immediately next to the rollers so as to cause the
water to impinge against the crushed material as it leaves the rollers, as I find that the
broken bark and other debris, as well as the objectionable liquid constituents of the
wood, are in this way more easily removed, but of course I do not wish to confine
myself to applying the water in the form of jets, as any plan by which the crushed
material may be washed with water as it leaves the rollers will answer.
If it is desired to use the stock thus prepared in the manufacture of cordage or
woven textile fabric, the said stock may be sufficiently cleansed by macerating it in
water sufficiently long to make it suitable for that purpose. Therefore it is not
absolutely necessary to submit it to a following operation of a boiling solution of caustic
alkali.
If, however, the stock is to be used for the manufacture of paper I place it in a
boiler containing a weak solution of caustic alkali, with preferably a small quantity of
an alkaline sulphite added, and boil it at a temperature of about 212 degrees Fahr.
for about six hours, which boiling will be found sufficient to remove all the silica or
other ingredient of the wood which might discolor or otherwise injuriously affect the
stock for paper making. After thus boiling the stock it may be reduced to pulp by

page_text: an ordinary beating engine or reducing machine, and the preparation of the pulp
continued in any of the well-known processes now employed in preparing the same.
I have found that about ten per cent. of caustic alkali to a given quantity of stock
will make a solution sufficiently strong to remove the silica and other objectionable
ingredients, and I have also found that by adding about one per cent. of an alkaline
sulphite to the solution, discoloration of the stock while boiling, is in a great measure
prevented; but I do not wish to confine myself to any exact proportion, nor do I wish
to limit myself to any specific length of time during which the boiling should take
place. The substantial advantage of my process resides in the fact that green wood
may be crushed and washed so as to remove the objectionable ingredients of the wood
to such an extent that a very weak solution of alkali is sufficient to complete the
cleansing operation.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is :
1. The within described process for preparing wood stock suitable for the
manufacture of paper, cloth, cordage, or any other textile fabric, which consists in
crushing freshly cut or green wood and washing it while being crushed, and, and
particularly for the manufacture of paper, in boiling it in a weak solution of caustic
alkali, substantially as described.
2. The within described process for preparing wood stock suitable for the
manufacture of paper, cloth, cordage, or any other textile fabric, which consists in
crushing freshly cut or green wood and washing it while being crushed, and,
particularly for the manufacture of paper, in boiling it in a weak solution of alkali,
with a small proportion of an alkaline sulphite added, substantially as described.
Dated this 11th day of June 1889
FREDERICK JOHN CHEESBROUGH.
By Cheesbrough & Royston,
15, Water Street, Liverpool, Patent Agents.