IMPROVEMENTS IN THE MANUFACTURE OF PAPER
Year: 1856

page_text: LETTERS PATENT to George Bertram, of Edinburgh, in the County of
Mid Lothian, Engineer, and William McNiven, Manager, Polton Mill,
Lasswade, of the same County, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF PAPER."
Sealed the 6th January 1857, and dated the 8th November 1856.
PROVISIONAL SPECIFICATION left by the said George Bertram and
William McNiven at the Office of the Commissioners of Patents, with
their Petition, on the 8th November 1856.
We, GEORGE BERTRAM, of Edinburgh, in the County of Mid Lothian,
Engineer, and WILLIAM MCNIVEN, Manager, Polton Mill, Lasswade, of the
same County, 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 improved arrangements of parts as well as the
mechanical action or working of what is technically known by paper-makers
as the "knotting machine," or pulp strainer, by which improved arrangements
and action a more effective knotting or pulp straining action is secured than
has hitherto been the case. The improved apparatus takes two general forms.
Under one of these forms the sieve or pulp-straining plate is disposed so as to
form the flat bottom of a vibrating frame, arranged to work upon a fixed
entre at one end, whilst it is connected at its opposite end to an eccentric

page_text: cam, crauk, or other movement, to give the frame a vertical vibratory action;
or instead of setting the strainer or sieve frame upon a fixed centre, it may be
worked from both ends, either with a horizontal, or see-saw, or other move-
ment. The strainer plate is surrounded on its lower face with a flexible bag-
like piece of vulcanized caoutchouc or other suitable flexible material. This
flexible bag forms the connection between the bottom of the sieve frame and
the bottom of a stationary chamber, in which the sieve frame vibrates. In
this way whatever pulpy matter falls through the strainer plate is conducted
by the flexible bag directly down upon that portion only of the bottom of the
surrounding chamber which is embraced by the lower end of the bag. In
the bottom of this fixed chamber there is a horizontal slide valve, governing
the entrance to the upper end of a duct, by which the cleansed pulp is drawn
off for use in the after process of actual paper making. The crude pulp is
supplied to the vibrating strainer by its open top, and the rapid shaking
vibratory movement communicated to the sieve frame, in conjunction with tho
action of the flexible bag at the bottom of the frame, produces a most efficient
suction or forcing pressure upon the pulpy mass. This action forces the
cleansed pulp rapidly through the strainer plate, whilst none of the pulp can
escape out into the open portion of the surrounding chamber, but is retained
within the area inclosed by the flexible bag.
Under another form this improved apparatus involves the use of a cylindrical
sieve or strainer. Instead of being flat, as in the former instance, the sieve is
formed into a hollow cylinder or permeable drum, disposed so as to revolve
horizontally in an open fixed chamber containing the pulpy mass to be strained.
The two end spindles of this cylinder are tubular, and one is connected with a
pump or exhaust apparatus of any convenient kind, whilst the other is similarly
connected with a steam or air pressure pipe. The strained pulp is drawn off
from the outer chamber through the interstices of the cylindrical strainer, and
is thence conducted through the tubular cylinder to the apparatus where it is
to be converted into paper. Whilst this exhausting action is going on air or
steam is allowed to enter by the other end spindle, and provision is thus made
that a powerful shake or regurgitation may be given to the pulp during its
extraction.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Bertram and William M Niven in the Great Seal
Patent Office on the 7th May 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, wc, GEORGE
BERTRAM, of Edinburgh, in the County of Mid Lothian, Engineer, and
WILLIAM MCNIVEN, Manager, Polton Mill, Lasswade, of the same County,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of November, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto us, the said
George Bertram and William McNiven, Her special license that wo, the
said George Bertram and William M°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
MANUFACTURE OF PAPER," upon the condition (amongst others) that we, the
said George Bertram and William McNiven, by an instrument in writing
under our bands and seals, or under the hand and seal of one of us, 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that we, the said George Bertram and William
M 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 in writing, reference being had to
the accompanying Drawings, and to the letters and figures marked thereon,
that is to say:-
Our said Invention relates to improved arrangements of parts as well as
the mechanical action or working of what is technically known by paper-
makers as the "knotting machine," or pulp strainer, by which improved
arrangements and action a more effective knotting or pulp-straining action is
secured than has hitherto been the case. The improved apparatus takes two
:

page_text: general forms. Under one of these forms the sieve or pulp-straining plate is
disposed so as to form the flat bottom of a vibrating frame, arranged to work
upon a fixed centre at one end, whilst it is connected at its opposite end to an
eccentric cam, crank, or other movement, to give the frame a vertical vibratory
action; or instead of setting the strainer or sieve frame upon a fixed centre,
it may be worked from both ends, either with a horizontal, or see-saw, or other
movement. The strainer plate is surrounded on its lower face with a flexible
bag-like piece of vulcanised caoutchouc or other suitable flexible material.
This flexible bag forms the connection between the bottom of the sieve frame
and the bottom of a stationary chamber, in which the sieve frame vibrates. In
this way whatever pulpy matter falls through the strainer plate is conducted
by the flexible bag directly down upon that portion only of the bottom of the
surrounding chamber which is embraced by the lower end of the bag. In the
bottom of this fixed chamber there is a horizontal slide valve, governing
the entrance to the upper end of a duct, by which the cleansed pulp is drawn
off for use in the after process of actual paper making. The crude pulp is
supplied to the vibrating strainer by its open top, and the rapid vibratory
movement communicated to the sieve frame, in conjunction with the action
of the flexible bag at the bottom of the frame, produces a most efficient
suction or forcing pressure upon the pulpy mass. This action forces the
cleansed pulp rapidly through the strainer plate, whilst noue of the pulp can
escape out into the open portion of the surrounding chamber, but is retained
within the area inclosed by the flexible bag.
Under another form this improved apparatus involves the use of a cylindrical
sieve or strainer. Instead of being flat, as in the former instance, the sieve is
formed into a hollow cylinder or permeable drum, disposed so as to revolve
horizontally in an open fixed chamber containing the pulpy mass to be strained.
The two end spindles of this cylinder are tubular, and one is connected with a
pump or exhaust apparatus of any convenient kind, whilst the other is similarly
connected with a steam or air pressure pipe. The strained pulp is drawn off*
from the outer chamber through the interstices of the cylindrical strainer, and
is thence conducted through the tubular cylinder to the apparatus where it is
to be converted into paper. Whilst this exhausting action is going on air or
steam is allowed to enter by the other end spindle, and provision is thus made
that a powerful shake or regurgitation may be given to the pulp during its
extraction.
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

page_text: showing certain modifications under which our improvements may be judiciously
carried out in practice.
Figure 1 on our Sheet of Drawings is an end elevation of a "knotting
machine," or pulp strainer, as arranged according to our improvements.
Figure 2 is a vertical section, and Figure 3 a plan, corresponding to Figure 1.
Figure 4 is a longitudinal elevation of another modification or arrangent of
a "knotting machine," or pulp strainer, being on the rotatory principle.
Figure 5 is a vertical section, and Figure 6 a plan of the same, corresponding
to Figure 4. In the arrangement of the knotting machine, shown in Figures
1, 2, and 3 of our Sheet of Drawings, an oblong rectangular frame or case A,
made either of iron, wood, or other suitable material, forms a chest or vat in
which the strained pulp is received. The interior of the frame A is formed
into two chambers, one of which B is parallel with the sides of the frame the
other chamber C is formed by the horizontal plate D, which extends from the
plate which encloses the chamber B to the opposite side of the machine. In
this last chamber C the sieve or strainer through which the pulp passes is
fitted; it consists of a brass frame E, in the lower part of which the sieve F
is fitted. The frame or strainer E extends nearly the whole length of the
chamber C each of its upper corners has a projecting horn or eye, by means
of which it is attached to the horizontal longitudinal side rods G. The ends
of the side rods G are connected by means of the vertical rods II to the
cross heads I, and these cross heads are attached by means of the rods J to
the eccentrics K. The eccentrics K are fast on the horizontal shaft L, which
passes in a longitudinal direction beneath the chamber C, and to this shaft a
rotatory motion is given from a suitable prime mover, either by means of a
belt pulley arrangement or bevil gearing. In order to prevent the weight of
the strainer E, and the pulp contained within it when in action, from being
thrown upon the eccentrics K at each end of the machine, a curved steel
spring M is attached by means of screws and nuts to a bracket N, which
projects from the ends of the frame A. The lower ends of the rods II, which
pass through the cross heads I, rest upon the outer ends of the curved springs
M, the tensional pressure of which against the rods or cross heads is regulated
by means of the screws and nuts which attach the spring to the brackets N.
The effect of attaching the strainer to the cross heads will be, that a vertical
shaking movement or a rising and falling action will be communicated to the
strainer when the eccentrics are put in motion by means of the shaft L. The
pulp to be strained is forced through the meshes of the sieve F by means of
atmospheric pressure produced in the following manner:-To the under sido
of the frame E of the sieve or strainer is attached one edge of a picco or

page_text: pieces of vulcanized caoutchouc or other suitable flexible material. This belt
or piece of caoutchouc O is carried round the frame E, and fastened thereto in
an air-tight manner by means of strips of copper fastened to the frame by
screws or rivets. The lower edge of the belt of caoutchouc is fastened to the
horizontal plate D, which forms the bottom of the chamber C, and in which
the strainer is fitted. The edge of the caoutchouc is firmly secured by means
of clamps of wood or metal; these clamps P are fastened to the plate D;
by bolts and nuts. The belt of caoutchouc thus encloses the space below the
strainer, so that when the strainer is filled with pulp in a semi-fluid state it
forms an air-tight or nearly air-tight chamber. When a vertical vibratory
motion is given to the strainer, the finer portions of the pulp are forced through
the slits or openings in the sieve or strainer by the pressure of the atmosphere
on the surface of the senii-fluid pulp when the strainer is lifted, this action
causing a partial vacuum below the strainer. The upward motion of the
strainer will obviously cause a layer of the pulp to be deposited upon the
surface of the sieve or strainer through which the finer particles of the pulp
pass, but the downward motion of the strainer causes the air contained within
the chamber to be forced through the slits or openings in the sieve, and the
film of the pulp is thereby removed. Thus, by the alternate elevation and
depression of the strainer, the pulp is rapidly and effectively passed through
the interstices of the sieve. The chamber or space below the strainer is fitted
with one or more pipes or ducts, by means of which the cleansed pulp is
conveyed into the chamber B of the vat. The entrance to each of these
pipes or ducts is governed by a horizontal slide valve, which is actuated by a
spindle passing through the sides of the vat, and furnished with a handle,
by means of which the workman opens or shuts the valve as required. In
our Sheet of Drawings one of these pipes or ducts Q is shown in the
sectional view, Figure 2. The pipe is carried downwards and into the lower
part of the chamber B; the horizontal slide valve R is shown closing the
upper end of the pipe or duct Q. The pulp flows down the pipe Q and into
the chamber B, in which is fitted an agitator or "hog" S, to which a rotatory
motion is given, in order to keep the pulp in an uniform state of suspension
in the water. From the chamber B the pulp flows over the "breast" T
of the vat towards the wire cloth of the machine, by means of which
it is converted into paper. Instead of thus working the strainer, the action
may be given from one side only, whilst the strainer frame is supported on
fixed centres on the other.
Another modification of our improvements in machinery or apparatus
for straining or cleansing pulp is shown in Figures 4, 5, and 6 of our

page_text: Sheet of Drawings. In this arrangement the sieve or strainer is formed
into a hollow cylindrical or polygonal drum. The exterior of this drum is
covered with sieve plates of the ordinary kind, so that the entire periphery
of the drum is permeable for the finer particles of the pulp to pass through
into its interior. In this arrangement the vat U may be made of wood,
cast iron, or other suitable material; it consists of a deep chamber V, in
which the strainer W is fitted. In the illustrative Figures the strainer is
showa of a square form in its cross section; the corner bars X, forming the
frame of the drum, are attached to and supported by the metal crosses Y, fitted
on the tubular spindle Z. The hollow spindles or gudgeons Z pass through the
ends of the vat U, and are fitted with stuffing boxes and plugs, by means of
which the drum or strainer may be connected with the pipes a and b, and
the junctions kept air and steam tight. The periphery of the drum alone is
made of sieve plates c; the ends of the drum are made solid. The pipe a, which
communicates at one end with the interior of the drum or strainer through its
hollow shaft or gudgeon, serves to convey steam or air into the strainer. The
other pipe 6 is carried upwards, and communicates by means of a double
branched piped with a vat or reservoir e, and with an air pump f, by means.
of which the interior of the strainer is exhausted of air. The pipe d is fitted
with valves for discharging the pulp into the reservoir or vat e, whence it flows;
through the pipe g to the chamber h, and over the "breast" to the machine.
The unstrained pulp is placed in the vat U, and a rotatory motion is given to
the strainer by means of a belt pulley arrangement, or other means of commu-
nicating motion thereto. The pumpf is then put in motion and the air drawn
off from the interior of the strainer; this has the effect of causing the pulp to
be forced through the interstices of the strainer by reason of the increased or
unbalanced atmospheric pressure on its exterior. Instead of obtaining this
partial exhaustion of the interior of the strainer in this way, it may be pro-
duced by means of a fan or exhauster fitted to the pipe communicating with
one end. of the strainer. The exhaustion of the strainer may also be effected
by means of bellows, or other suitable apparatus for producing suction, or the
removal of the air from the interior of the strainer. Instead of arranging
the strainer in a horizontal position, as shown in our Sheet of Drawings, it
may be fitted either in a perpendicular. or angular direction, and be made
either stationary or moveable, as may be most convenient. In the arrange-
ment herein-before described the motion communicated to the strainer is
rotatory, but in some cases it may be preferable to give it a partially rotatory
or an oscillating movement, which may be effected by means of cams, eccentrics,
or other convenient mechanical arrangements, fitted to the hollow spindles or

page_text: gudgeons of the strainer. The effect of partially exhausting the air from the
interior of the strainer may be increased by introducing steam or air under
pressure through the pipe a, which will cause the pulp to be driven through
the pipe
with increased velocity, and thereby facilitate the operation of
cleansing the pulp.
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 arrangement and construction of machinery or apparatus for
straining and cleansing pulp to be used for the manufacture of paper, as
herein-before described.
Second, the system or mode of straining pulp by means of machinery or
apparatus in which the strainer with its frame has a vertical vibratory motion
imparted to it by means of eccentrics, or other mechanical equivalent, as
herein-before described.
Third, the system or mode of arranging and constructing vats for straining
pulp, in which a flexible diaphragm is fastened to the frame of the strainer and
to the bottom of the chamber or vat, as herein-before described.
Fourth, the arrangement and construction of hollow or tubular strainers,
whether of a cylindrical or polygonal shape, and either stationary or moveable,
as herein-before described.
Fifth, the system or mode of straining or cleansing pulp by means of hollow
or tubular strainers, and used in conjunction with an exhausting apparatus, or
with an exhausting and forcing apparatus, as herein-before described.
In witness whereof, I, the said George Bertram, on behalf of myself
and the said William M°Niven, have hereunto set my hand and seal,
this Fifth day of May, One thousand eight hundred and fifty-seven.
CHODAR DEOTD LY
GEORGE BERTRAM. (L.C.)