IMPROVEMENTS IN MACHINERY FOR WASHING FIBROUS PULP OR MATERIAL FOR THE MANUFACTURE OF PAPER
Year: 1872

page_text: LETTERS PATENT to George Davidson, of Mugie Moss Paper Works,
Aberdeen, Scotland, for the Invention of "IMPROVEMENTS IN MACHINERY
FOR WASHING FIBROUS PULP OR MATERIAL FOR THE MANUFACTURE OF
PAPER."
Sealed the 3rd December 1872, and dated the 22nd June 1872.
PROVISIONAL SPECIFICATION left by the said George Davidson at
the Office of the Commissioners of Patents, with his Petition, on
the 22nd June 1872.
I, GEORGE DAVIDSON, of Mugie Moss Paper Works, Aberdeen,
Scotland, do hereby declare the nature of the said Invention for "Iм-
PROVEMENTS IN MACHINERY FOR WASHING FIBROUS PULP OR MATERIAL FOR THE
MANUFACTURE OF PAPER," to be as follows:-
This Invention has for its object improvements in machinery for
washing fibrous pulp or material for the manufacture of paper.
At the present time it is usual to wash paper pulp by means of a
drum, the periphery of which is of wire gauze. This drum is mounted
so that the lower part of its periphery dips into the pulp, and then the

page_text: water contained in the pulp runs through the gauze into the drum.
There are scoops within the drum which lift the water, and it is
discharged around the axis of the drum at one or both ends over the
sides of the tank. I substitute for this arrangement a flat sieve which
I cause alternately to dip into the pulp and to rise out of it. The
bottom of the sieve (or both bottom and sides) is of wire gauze, which
is covered on the upper side with flaps of vulcanized india-rubber or
other suitable material arranged like louvre boards. When the sieve
dips into the pulp the water runs through the gauze, the flaps not
opposing its passage. When the sieve is raised the flaps fall on the
gauze and prevent the water passing back through it, and the water is
poured out of the sieve over the side of the tank or rag engine.
I prefer to connect the sieve by one of its ends to a rocking axis in
such manner that when in the pulp the gauze is in a horizontal position
or nearly so, and when the sieve rises it becomes inclined and the water
within it runs towards the axis over the flaps which overlap, so that
the water has no tendency to pass between them. When the sieve is
thus mounted its motion assists the circulation of the pulp.
When the gauze becomes clogged it is easy to remove it with the
frame upon which it is fixed, and the gauze is thus readily cleared by a
stream of water.
In some cases in washing fibrous materials for the manufacture of
paper I exhaust the air to remove the water more rapidly. For this
purpose I enclose the sieve at the top, and when it is dipped into the
pulp I exhaust the air from it; this causes the water to pass through
much more rapidly than it otherwise would, and the water is then
delivered in the way already described.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Davidson in the Great Seal Patent Office
on the 20th December 1872.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of June, in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said George Davidson, Her special license
that I, the said George Davidson, my executors, administrators, and
assigns, or such others as I, the said George Davidson, my executors,
administrators, and 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
FOR WASHING FIBROUS PULP OR MATERIAL FOR THE MANUFACTURE OF PAPER,"
upon the condition (amongst others) that I, the said George Davidson,
my executors or administrators, by an instrument in writing under my,
or their, or one of their hands and seals, 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 Scal
Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said George Davidson, 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 thereof, that is to say :-
This Invention has for its object improvements in machinery for
washing fibrous pulp or material for the manufacture of paper.
At the present time it is usual to wash paper pulp by means of a drum,
the periphery of which is of wire gauze: This drum is mounted so that
the lower part of its periphery dips into the pulp, and then the water
contained in the pulp runs through the gauze into the drum.
There are
scoops within the drum which lift the water, and it is discharged around
the axis of the drum at one or both ends over the sides of the tank. I
substitute for this arrangement a flat sieve, which I cause alternately to
dip into the pulp and to rise out of it. The bottom of the sieve (or both
bottom and sides) is of wire gauze, which is covered. on the upper side
with flaps of vulcanized india-rubber or other suitable material arranged
like louvre boards. When the sieve dips into this pulp the water runs

page_text: Figure 1 is a vertical section of my washer, shewing the position of
washer board or frame A having the wire cloth a', and the louvre flaps a³,
which I prefer to be of vulcanised india-rubber attached to it. The
board A is itself attached to the wooden tray B, so that it may be readily
removed when it becomes necessary to clean the wire cloth.
Figure 2 is a plan of the washer, the dotted lines shewing the overlap
of the louvre flaps; part of the rocking shaft C is also shewn in this
Figure. This shaft is firmly fastened to the tray B by the arms D,
shewn in Figure 1. Each louvre flap is fixed along one of its edges to
one of the bars of the washer board or frame A, and is free on the other
side.
Figure 3 represents the front side elevation of an ordinary paper mill
rag engine, shewing my washer placed in it, and the method of driving
the same. It is driven from the shaft of the rag engine roll E by the
pinion F geared into the wheel G, which is carried upon the stud H, and
has fixed into it the stud pin I working in the connecting rod K which
drives the lever L through the stud pin M, giving thereby to the shaft C
a rocking motion which alternately dips the washer into the pulp in the

page_text: rag engine, and again raises it, so that the water lifted in the washer
is emptied out of it into the spout N, and run by it over the side of the
rag engine.
The washer, as described in these three Figures is in its simplest form
in so far as it only has one washer board A. These "louvre washer
boards "
(as I call them) may, however, be increased in number, as
shewn in vertical section and plan at Figures 4 and 5, where the louvre
frames are inclined in opposite directions, so as to obtain a more extended
surface. The india-rubber louvre flaps are only represented in one
division of Figure 5.
The louvre washer boards are fitted into the washer trays by grooves,
in which they slide. By this means a board can at any moment be
withdrawn for cleaning or repairing it, and a spare board put in its
place, so that the machine need not at any time be stopped for repairs
or cleaning.
Sometimes I make the board or frame to which the louvre flaps are
fastened separate from the board or frame to which the wire cloth is
fastened. The two, however, being fastened together to form a "louvre
washer board" the object of making them so is that they can be
separated to facilitate the washing and repairing of the wire cloth.
What I claim is, the construction of "washers" to be used for washing
fibrous pulp or material for the manufacture of paper with louvre flaps,
substantially as described.
In witness whereof, I, the said George Davidson, have hereunto set
my hand and seal, this Eighteenth day of December, in the
year of our Lord One thousand eight hundred and seventy-two.