IMPROVEMENTS IN THE MANUFACTURE OF PAPER PULP FROM VEGETABLE FIBRES, AND IN APPARATUS THEREFOR, WHICH APPARATUS IS ALSO DESIGNED TO BE EMPLOYED IN MAKING CHLORIDE OF LIME FOR BLEACHING PULP, AND IN OTHER SIMILAR PROCESSES
Year: 1871

page_text: *PROVISIONAL SPECIFICATION left by William Riddell at the Office
of the Commissioners of Patents, with his Petition, on the 7th
December 1871.
I, WILLIAM RIDDELL, of Crosby Hall Chambers, Bishopsgate Street,
in the City of London, and of Hurstbourne. Mill, near Whitchurch,
in the County of Hants, Civil Engineer, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF PAPER
PULP FROM VEGETABLE FIBRES, AND IN APPARATUS THEREFOR, WHICH APPARATUS
IS ALSO DESIGNED TO BE EMPLOYED IN MAKING CHLORIDE OF LIME FOR BLEACHING
PULP, AND IN OTHER SIMILAR PROCESSES," to be as follows:-
In the manufacture of paper pulp according to my Invention, I take
wood, esparto grass, or other suitable vegetable fibrous substances, and
soak the same in cream of lime (hydrate of lime), or boil or steam them;
in some cases I may boil them in cream of lime. They are then
bleached either by the ordinary process or by first gassing them, and
then treating them with a solution of chloride of lime.
Esparto and other similar fibres after being steamed by the process
described in the Specification of an Invention for which I have obtained

page_text: Letters Patent, bearing date the Sixth day of April, in the year of
our Lord One thousand eight hundred and seventy-one, No. 923, arc
afterwards washed in warm water and then boiled in cream of lime,
and again washed with warm water. They are then pulped in a pulping
engine, and bleached first by gassing, with chlorine gas, washing and
afterwards steeping in a weak solution of chloride of lime.
The gassing may be accomplished by any suitable apparatus, but
I prefer to use my improved gassing apparatus which is constructed
as follows:-The said apparatus has a spiral conductor arranged within
a drum or case. The gas or liquid is admitted into the lower part
of this conductor through an aperture at its centre, and the fibres to be
treated are admitted to the same part thereof through a hopper at the
top. By the revolutions of the drum containing this spiral conductor
the fibres are carried forward from the hopper to the delivery aperture,
and during this passage they are continually turned over, and thereby
every portion of the fibre is equally and thoroughly exposed to the
action of the chlorine gas or liquid. The unused or unspent gas is
conducted through water containing lime or into a chamber containing
dry lime and is thereby condensed.
The aforesaid spiral conductor is constructed in the following manner :-
Its central part is a shaft or core of wood, preferably of about twelve
inches in diameter and about twenty feet long. On this shaft I turn a
spiral groove or channel extending from end to end of the same. Into
this groove I fit pieces of wood to form a thread or spiral, the pitch
thereof being about six inches, and the depth about two feet. Over this
thread I place planks or strips of wood, which are well fitted together
and fastened with screw hoops like a barrel. The interior of this barrel,
together with the thread and also the core, may if required have a
metallic covering, and in some cases the apparatus may be made of iron
or other metal.
The wooden barrel containing the thread or worm is supported to turn
freely upon antifriction rollers, and is provided at one end with a row
of cogs round the barrel forming a toothed wheel, which is geared into
another toothed wheel or pinion whereby the said barrel is operated.
At the end where the gas or liquid is admitted the shaft is made
hollow and provided with a tube or pipe. The latter has at its outer
extremity a stuffing box whereby it is coupled to a stationary pipe,
which is connected to a reservoir or chamber containing the chlorine
b. i

page_text: gas or liquid. These pipes conduct the said gas or liquid into the
centre of the wooden core, whence it is admitted through a lateral
aperture into the first coil of the spiral conductor. The hopper for
admitting the fibres is also placed over the same coil.
When the apparatus is used for the manufacture of chloride of lime,
the chlorine gas is admitted as above described through the central pipe
into the spiral conductor, and the lime is admitted through the hopper.
And in other like chemical processes or operations the substances used
will be admitted to the conductor through the same passages.