IMPROVEMENTS IN THE MANUFACTURE OF PAPER.
Year: 1858

page_text: LETTERS PATENT to George Bertram, of Edinburgh, in the County of
Mid Lothian, Engineer, and William McNiven, Polton Mill, Lasswade,
in the same County, Manager, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF PAPER.".
PROVISIONAL SPECIFICATION left by the said George Bertram and
William McNiven at the Office of the Commissioners of Patents, with
their Petition, on the 4th February 1858.
We, GEORGE BERTRAM, of Edinburgh, in the County of Mid Lothian,
Engineer, and WILLIAM MCNIVEN, Polton Mill, Lasswade, in the same
County, Manager, do hereby declare the nature of the said. Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF PAPER;" to be as follows, that is to
say:-
This Invention relates to what is technically known by paper makers as
the "knotting machine," or pulp strainer, as used in the paper manufacture
for straining or "knotting" the pulp as a cleansing process prior to its actual
conversion into paper; and it bears more or less upon an Invention of
"Improvements in the Manufacture of Paper," for which British Letters
Patent were granted to George Bertram and William McNiven on or about
the Eighth day of November, One thousand eight hundred and fifty-six.

page_text: movement.
The present Invention may be judiciously carried out in practice under
three several leading forms, in addition to. minor modified arrangements which
particular circumstances may require. In one of these, where a cylindrical
straining sieve is used, such, for example, as the arrangement described in the
Final Specification of the previous Patent of 1856, a" bellows" or expanding
and contracting apparatus is placed in the interior of the cylindrical sieve.
This "bellows," or expanding and contracting apparatus consists of a duplex or
other set of cylindrical discs, each pair being connected by means of leather or
other flexible material; so as to. form expanding and contracting apparatus re-
sembling the circular or cylindrical bellows of the smith's shop. These two or
other sets of bellows' movements are disposed with their axes coincident with
the horizontal axis of the cylindrical sieve, and their working discs are connected
by means of a spindle passing outwards with a crank or other reciprocatory
The interior of the bellows apparatus communicates by a suitable
duct with the external atmosphere. The effect of this arrangement is that
the alternate expanding and collapsing movement of the bellows apparatus
keeps the sieving medium clear of deposit, so that the pulp has always a more
effective straining medium before it in passing from the source of supply into
the interior of the cylinder. The strained pulp is withdrawn from the interior
of the cylinder at a lower level than the height of the pulp in the supplying
vat. The expanding and collapsing or contracting arrangement may be made
and worked in various ways, so as to obtain the necessary alterations of bulk
in the interior of the cylinder. Instead of this arrangement, a stationary or
fixed frame may be used with a sieve or strainer bottom in it, the strained
pulp being passed upwards through the sieving or straining medium by the
action of a, bellows or expanding and, contracting motion, such, as has, been
already described herein. In the, present instance the bellows are arranged
to work in a chamber beneath the sieve bottom; and in a third plan a fixed
sieve bottom and frame are used with a bellows arrangement beneath, causing
the strained pulp to pass down through the bottom. In arrangements where
the pulp is strained upwards through a sieve bottom or through a cylindrical
sieve, the under or inner surface of the sieving medium, or that surface
against which the pulp first comes, may be kept clear of deposited matter, by
the use of a traversing brush or mechanical cleanser.

page_text: 1
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George. Bertram and William McNiven in the Great Seal
Patent Office on the 4th August 1858..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
BERTRAM, of Edinburgh, in the County of Mid Lothian, Engineer, and WILLIAM
M NIVEN, Polton Mill, Lasswade, in the same County, Manager, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of February, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us, the
said George Bertram and William.M° Niven, Her special license that we, the
said George Bertram and William Mo Niven, our executors, administrators,
and assigns, or such others as we, the said George Bertram and William
McNiven, our 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 THE MANU-
FACTURE OP PAPER," upon the condition (amongst others) that we, the said
George Bertram and William M°Niven, by an instrument in writing under
our hands and seals, or under the hand and seal of one of us, should par-
ticularly 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that we, the said George Bertram and William
Mo Niven, 'do hereby declare the nature of our said Invention, and in what
manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement, reference being had to the accom-
panying Drawings and to the letters and figures marked thereon, that is to.
say:-
Our said 'Invention relates to what is technically known by paper makers
as the "knotting machine," or pulp strainer, as used in the maper manu-
facture for straining or "knotting" the pulp as a cleansing process.prior to
its actual conversion into paper; and it bears more or less upon an Invention
of "Improvements in the Manufacture of Paper," for which British Letters
Patent were granted to us on or about the Eighth day of November, One

page_text: "
thousand eight hundred and fifty-six. The present Invention may be judi-
ciously carried out in practice under three several leading forms, in addition
'to minor modified arrangements which particular circumstances may require.
In one of these, where a cylindrical straining sieve is used, such, for example,
as the arrangement described in the Final Specification of the previous Patent
of One thousand eight hundred and fifty-six, a "bellows" or expanding and
contracting apparatus is placed in the interior of the cylindrical sieve. This
"bellows or expanding and contracting apparatus consists of a duplex or
other set of cylindrical discs, each pair being connected by means of leather
or other flexible material, so as to form expanding and contracting apparatus
resembling the circular or cylindrical bellows of the smith's shop. These two
or other sets of bellows' movements are disposed with their axes coincident
with the horizontal axes of the cylindrical sieve, and their working discs are
connected by means of a spindle passing outwards, with a crank or other
reciprocatory movement. The interior of the bellows apparatus communi
cates by a suitable duct with the external atmosphere. The effect of this
arrangement is that the alternate expanding and collapsing movement of the
bellows apparatus keeps the sieving medium clear of deposit, so that the pulp
has always a more effective straining medium before it in passing from the
source of supply into the interior of the cylinder. The strained pulp is with-
drawn from the interior of the cylinder at a lower level than the height of
the pulp in the supplying vat. The expanding and collapsing or contracting
arrangement may be made and worked in various ways, so as to obtain the
necessary alternations of bulk in the interior of the cylinder. Instead of this
arrangement a stationary or fixed frame may be used, with a sieve or strainer
bottom in it, the strained pulp being passed upwards through the sieving or
straining medium by the action of a bellows or expanding and contracting
motion, such as has been already described herein. In the present instance
the bellows are arranged to work in a chamber beneath the sieve bottom,
nd in a third plan a fixed sieve bottom and frame are used, with a bellows
arrangement beneath, causing the strained pulp to pass down through the
bottom. In arrangements where the pulp is strained upward through a sieve
bottom, or through a cylindrical sieve, the under or inner surface of the
sieving medium, or that surface against which the pulp first comes, may be
kept clear of deposited matter by the use of a traversing brush or mechanical
cleanser.
And in order that our said Invention' may be properly understood, we shall
now proceed to describe the several illustrative Figures on the explanatory Sheet
of Drawings which we have hereunto appended for the purpose of showing

page_text: certain modifications under which our improvements may be judiciously carried
out in practice.
Figure 1 on our Sheet of Drawings is a longitudinal vertical section of one
arrangement of our improved knotting machine; Figure 2 is a section, corre-
sponding to Figure 1; but taken at right angles thereto, that is to say, across
the machine instead of in the direction of its length; Figure 3 is a plan; and
Figure 4, an end view, corresponding to Figure 1. According to this modi-
fication of our improvements, the vat A or holder in which the impure pulp
is contained is a cast-iron vessel, the bottom of which is of a semicircular
figure, and forms an incline that extends from one end of the machine to
the other, as shown in the longitudinal section, Figure 1. At the lower
end of the inclined bottom an aperture is made in the end standard, which
aperture is fitted with a plug B, or with a valve or cock, by opening
which, the vessel A may be washed or otherwise cleaned out when neces-
sary: Within the vat A is arranged a strainer, through the interstices
of which the finer particles of the impure or uncleansed pulp are drawn
by means of an air-displacing process. The strainer consists of two brass
end plates or discs C formed with tubular or hollow gudgeons D, which are
supported in brass bushes that are fitted into circular apertures cast in the
ends of the vat A, the gudgeons D being ground into the bushes, so as to
rotate therein without leakage. The end plates C are connected to each other
by brass rods or bars E, upon which are arranged the segmentally shaped
perforated plates F, these from the cylindrical strainer through which the pulp
is drawn. The plates F are made of brass, and are cast with transverse ribs
on their under sides, as shown in Figure 1 of our Drawing. . In the thinner
part of the metal between these ribs are made series of slits or narrow longi-
tudinal openings, to admit of the passage of the pulp to the interior of the
strainer. In this arrangement the periphery of the cylindrical strainer is
made up of three of the strainer plates F, and there are three series of these
plates disposed with their ends abutting against each other, to make up thé
length of this part of the apparatus. The ends and abutting parts of the
strainer plates F are secured to the framing of the strainer by means of copper
hoops G, which bind and retain the plates thereon. Outside, the plates F and
upon their abutting longitudinal edges are fixed three radial floatboards or
wings H, which serve to agitate and prevent the settlement of the pulp when
the strainer is put in motion. Rotatory motion is communicated to the
strainer from a steam engine or other prime mover through the shaft I and
pinion J to the spur wheel K that is keyed upon the right-hand tubular
gudgeon D. In this manner a slow rotatory movement is imparted to the

page_text: strainer, and at the same time the air is rarefied and put into rapid motion
from the interior thereof, so that the pulp is forced through the interstices of
the plates F, partly by the external atmospheric pressure, and by the means
made use of for keeping the interstices of the plates F clear of deposit.
This effect is obtained by using flexible air vessels, similar in construction
to the circular bellows in ordinary use; in this modification there are
three of these air vessels arranged equidistant and parallel to the end
plates C.. Each of these air vessels consists of a pair of end plates or
discs L and M, which are connected to each other by a flexible belt or ring
N formed of vulcanised or mineralised india-rubber, or other air-proof
material. In the first or right-hand air vessel, shown in Figure 1, the end
plate C of the strainer forms one of the discs of that vessel. The flexible
belts N, which form the central or main portion of each air vessel, are
secured to the end plates by rings or hoops of copper, which are riveted or
bolted to the rims of the end plates C, L, and M, so that each forms a perfectly
air and water tight chamber. The right-hand end plates M of the two inner
or: left-hand air vessels are held concentrically within the strainer by the
radial supporting arms O, which are made with concave or forked ends to
admit of their sliding to and fro upon the longitudinal bars E. The opposite
or left-hand end plates L are made fast to discs or centres P, which are
arranged upon the central shaft Q; these centres are fixed in their proper
positions by nuts, which are fitted to threads cut upon the shaft Q. The end
plate L of the innermost or left-hand air vessel is secured to the shaft Q by a
simple nut, as shown in the sectional view, Figure 1, of our Drawing. The
end plates L of the two outermost or right-hand air vessels are made with
tubular centres, which project laterally therefrom; to each of these tubular
parts are secured the ends of two intermediate flexible tubes R. The other
extremities of the tubes R are in like manner secured to two copper tubes S,
which are riveted or otherwise fastened to the plates M of the two inner or
left-hand.air vessels. In this manner the three air vessels are connected to
each other, while the shaft Q passes throughout the series; the outer end of
this shaft passes through a brass bush fitted in the right-hand tubular gudgeon
D of the strainer. A short and rapid reciprocatory movement is imparted to
the shaft Q by means of the connecting rod T; which is actuated from a crank
or cam U on the shaft V; this shaft is driven by means of an endless belt
that derives its motion from a steam engine or other prime mover, and
imparts it to the cone pulleys W on the shaft V; but the shaft V is fast to the
end plates of the air vessels, and must therefore rotate with the strainer as well
as-give motion to the air vessels; this compound motion is obtained by making

page_text: the end of the connecting rod T where it is attached to the shaft Q with a
swivel joint to allow of the rotation of the shaft, at the same time that it is
receiving its reciprocatory movement from the crank. The unstrained pulp is
allowed to flow into the vat A until it covers the periphery of the strainer,
which is put in motion as well also as the shaft Q. The motion of the shaft Q
causes the air vessels to rapidly collapse and expand, the collapsing action
having the effect of rarefying or attenuating the volume of air contained within
the strainer. The consequence of this rarefaction is, that the pulp is forced
through the interstices of the strainer by the external atmospheric pressure.
And when the expansion of the air vessels takes place the air is suddenly put
in motion and forced outwards; the effect of this is to drive off from the
periphery of the strainer the film of particles that may have adhered; thereto.
In this manner the interstices of the strainer are kept constantly free and open
for the passage of the finer particles of pulp to pass through them, resulting in
the production of a very clear and superior quality of pulp. The cleansed.
pulp which has passed through the plates F flows off through the left-hand
tubular gudgeon D, the passage of which is controlled by a valve X into the
box or receiver Y. From the receiver Y the pulp passes through the pipe Z
into the "breast" a of the vat, from whence it flows on to the wire cloth of
the paper-making machine in the ordinary manner. The machinery for
effecting the straining of pulp by this mode of aerial displacement may also be
varied in its arrangement, and adapted to the modifications described in the
first part of this Specification.
Having now described and particularly ascertained the nature of our said
Invention, and the manner in which the same is or may be used or carried
into effect, we may observe, in conclusion, that we do not confine or restrict
ourselves to the precise details or arrangements which we have had occasion
to describe or refer to, as many variations may be made therefrom without
deviating from the principles or main features of our Invention; but what we
consider to be novel and original, and therefore claim as the Invention secured
to us by the herein-before in part recited Letters Patent, is,-
First, the general arrangement and construction of machinery or apparatus
for straining or preparing pulp for the manufacture of paper, as herein-before
described.
Second, the system or mode of straining, cleansing, or preparing pulp in
which the passage of the particles of pulp through the strainer is effected or
facilitated by the displacement or motion of the air contained within or in
immediate proximity to the strainer, as herein-before described.
Third, the system or mode of rarefying and agitating the air for the purpose

page_text: of drawing the particles of pulp through the interstices of the strainer plates,
and removing the film of unstrained particles therefrom, as herein-before
described.
Fourth, the use and application of flexible air vessels or any mere equivalent
therefor to the purpose of straining pulp, or facilitating the straining process,
as herein-before described.
Fifth, the use and application of curved or segmentally shaped strainer
plates in the formation or construction of cylindrical strainers or apparatus for
cleansing pulp, as herein-before described.
In witness whereof, I, the said George Bertram, on behalf of myself and
of the said William McNiven, have hereunto set my hand and seal, this
Second day of August, One thousand eight hundred and fifty-eight.
GEO. BERTRAM. (L.S.)