IMPROVEMENTS IN MACHINERY OR APPARATUS FOR STRAINING PAPER PULP
Year: 1870

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn
Fields, in the County of Middlesex, Gentleman, for the Invention
of "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR STRAINING PAPER
PULP." A communication from abroad by Jules Mathieu, of Paris,
in the Empire of France, Engineer.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition,
on the 23rd February 1870.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
5 of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR STRAINING
PAPER PULP," a communication from abroad by Jules Mathieu, of Paris,
.
in the Empire of France, Engineer, to be as follows:-
This Invention relates to pulp strainers employed in the preparation
of paper pulp, and consists of an apparatus wherein the pulp is strained
by centrifugal action. The surrounding cylindrical casing or straining

page_text: surface is composed of perforated metal or stout wire cloth, and is
disposed either vertically, horizontally, or obliquely, as found most con-
venient. Within this casing and concentrically thereto works a shaft
which carries a number of radiating metal blades or brushes made
adjustable towards or from the straining surface, so as to suit the
particular kind of pulp operated upon. A rapid rotatory motion is
imparted to the said shaft, whereby the pulp is driven by centrifugal
force through the straining surface, whilst those particles of straw or
other larger and more solid substances fall to the bottom inside the
apparatus, and finally pass out through openings for that purpose.
The shaft may be made hollow for the admission of water along with
the pulp into the strainer, or it may be solid, and the water be admitted
by pipes and cocks specially provided for the purpose.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 23rd August 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN HENRY
JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of February, in the
year of our Lord One thousand eight hundred and seventy, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Henry Johnson, Her special
license that I, the said John Henry Johnson, my executors, adminis-
trators, and assigns, or such others as I, the said John Henry Johnson,
my executors, administrators, or assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN MACHINERY OR APPARATUS FOR STRAINING PAPER PULP," a
communication from abroad by Jules Mathieu, of Paris, in the Empire
of France, Engineer, upon the condition (amongst others) that I,
the said John Henry Johnson, my executors or administrators, by an

page_text: instrument in writing under my hand and scal, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Henry Johnson, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the Drawing'
hereunto annexed, and to the letters and figures marked thereon, that
is to say:-
The said Invention relates to pulp strainers employed in the pre-
paration of paper pulp, and consists of an apparatus wherein the pulp
is strained by centrifugal action action. The surrounding cylindrical
casing or straining surface is composed of perforated metal or stout wire
cloth, and is disposed either vertically, horizontally, or obliquely, as found
most convenient. Within this casing and concentrically thereto works
a shaft which carries a number of radiating metal blades or brushes
made adjustable towards or from the straining surface, so as to suit the
particular kind of pulp operated upon. A rapid rotatory motion is
imparted to the said shaft, whereby the pulp is driven by centrifugal
force through the straining surface, whilst those particles of straw or
other larger or more solid substances fall to the bottom inside the
apparatus, and finally pass out through openings for that purpose.
The shaft may be made hollow for the admission of water along with
the pulp into the strainer, or it may be solid, and the water be admitted
by pipes and cocks specially provided for the purpose.
And in order that the said Invention may be fully understood, I shall
now proceed more particularly to describe the same, and for that purpose
shall refer to the several Figures on the annexed Sheet of Drawings,
the same letters of reference indicating corresponding parts in all the
Figures.
These Drawings shew as examples two types which may be employed,
together with a plan of the general arrangement of the plant.
Figure 1 is a vertical section taken through the centre, and Figure 2
a horizontal section taken along the line 1, 2, (Figure 1) of a vertical
strainer constructed according to this Invention.

page_text: The apparatus is composed of a casing E of perforated sheet metal or
stout wire gauze mounted in a frame C; in the interior of the casing
there is disposed a shaft A, which is caused to revolve, and carries three
wheels a, to which pallets are attached, the latter being provided either
with brushes or simply with metallic blades 7. The distance between
the brushes or blades and the casing is regulated by means of nuts and
counter nuts c, e¹. The pulp to be purified or strained is introduced into
the casing through the aperture D, and is distributed over the surfaces d,
.and the centrifugal force due to the high velocity which is imparted-to-
the shaft A, and consequently to the pallets, drives the pulp through the
holes or meshes-in-the casing. The size of these holes or meshes is
-determined by the nature of the pulp, so as not to admit of the passage
of the non-lexiviated particles of straw, pieces of wood, or other
extraneous matters which are discharged through the apertures O, 0¹,
provided at the lower part of the apparatus. The strained pulp falls
into a box which is disposed under the apparatus, and thence into any
suitable conduit to convey it to its destination, say, to the paper machine
in the case of stuff, or to the draining press in the case of half stuff.
The shaft A of the strainer, which in the Drawing is shown hollow,
may, however, be solid; when made hollow it admits of a certain
quantity of water being introduced towards the lower parts of the
apparatus, which facilitates the outlet of the pulp.
Figure 3 is a longitudinal vertical section, and Figure 4 is a corre-
sponding sectional plan, and Figure 5 a transverse section, taken along the
line 3, 4, (Figure 3) of a strainer disposed at an angle. This apparatus
is composed of parts in all respects similar to those described in reference
to Figures 1 and 2, any further description will therefore be unnecessary.
Figure 6 shews an example of the general arrangement of the plant.
H, H¹, are the worms which introduce the pulp to the strainers E, E¹,
whence it is discharged into the conduits C, C¹, through which it is
conducted to a press P. This arrangement of the plant will of course.
be varied according to the space at disposal and other circumstances.
Having now described and particularly ascertained the nature of the.
said Invention, and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that what I consider
to be novel and original, and therefore claim as the Invention secured
to me by the herein-before in part recited Letters Patent is, the system
of straining by centrifugal force, by which the pulp is caused to pass,

page_text: and becomes strained through a casing of perforated sheet metal or stout
wire gauze, whilst the residuum or waste particles are received at the
lower part of the apparatus, as herein-before described and illustrated
by the Drawings.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and seal, this Twenty-second day
of August One thousand eight hundred and seventy.
J. HENRY JOHNSON. (L.S.)