IMPROVEMENTS IN STRAINERS FOR STRAINING PAPER PULP
Year: 1872

page_text: LETTERS PATENT to James McMurray, of the Royal Paper Mills,
Wandsworth, in the County of Surrey, Paper Manufacturer, for
the Invention of "IMPROVEMENTS IN STRAINERS FOR STRAINING PAPER
PULP."
Sealed the 29th April 1873, and dated the 2nd November 1872.
PROVISIONAL SPECIFICATION left by the said James Mc Murray at
the Office of the Commissioners of Patents, with his Petition, on
the 2nd November 1872.
I, JAMES MCMURRAY, of the Royal Paper Mills, Wandsworth, in the
County of Surrey, Paper Manufacturer, do hereby declare the nature of
my said Invention for "IMPROVEMENTS IN STRAINERS FOR STRAINING PAPER
PULP," to be as follows:-
This Invention relates to a peculiar construction and arrangement of
rotatory strainer for straining paper pulp, whereby a considerable saving
in the first cost of construction is effected, less power is required for
driving the same, it is more regular and efficient in its action, as no

page_text: "knots
"
can be formed by reason of the absence of ratching surfaces in
contact with the pulp. The general arrangement is simple and not
liable to derangement, and the process of washing up, as compared with
the ordinary knotters, is greatly facilitated.
The main body of the improved strainer consists of a long rectangular
hollow metal case, the sides of which are provided with fine slits or
perforations for straining the pulp, as in the ordinary "knotter.". This
hollow perforated case consists of a skeleton frame, each longitudinal
bar of which is situate at one of the corners or angles of the "knotter"
or perforated case. The perforated sides consist of a number of separate
plates (say 3 on each side, which plates are each formed with projecting
tongues at suitable intervals along their opposite edges. These tongues
engage under corresponding tongues made at corresponding intervals
along the inner faces of raised fillets on each of the longitudinal corner
bars of the frame. The ends of the several perforated side plates, and
the inner faces of the end plates, the hollow perforated case are
respectively tongued and grooved so as to admit of their fitting accurately
.together when in position. The side plates are easily inserted and
removed by first dropping them between the tongues on the fixed fillets,
and then sliding them home longitudinally so as to interlock the two
sets of projecting tongues. On removing these plates they are first slid
back horizontally till their projecting tongues come between the tongues
on the fillets, whom they are free to be lifted out of the frame. The
several plates on each side or face of the "knotter" or hollow perforated
case are locked in position by a transverse perforated slide at one end of
the knotter, such slide being made to fit accurately by a tongue and
groove joint between the end of the last plate on the side and the fixed
end of the knotter. In order that these slides in the several faces
of the knotter may be retained in their places, and in their turn
retain the removeable perforated plates in position, one end of each slide
is made to project over the end of the next one, and the master slide,
or that which must first be removed before the rest can be withdrawn,
projects at both ends over the two adjoining slides. This master slide
is secured in its place by a single screw, and thus one screw is made to
hold in place the whole of the plates and slides in lieu of the great
number of screws which have heretofore been found necessary for this
purpose. A hollow trunnion is attached to each end of the knotter,
which trunnions work in bearings situate outside in lieu of inside the

page_text: vat as heretofore, hence the clogging up of the bearings by the pulp
becoming worked into them is entirely obviated.
Inside the above-described knotter there is or are placed one, two,
or more double truncated cones or pyramids, mounted axially upon a
central spindle, to which a rapid longitudinal reciprocating motion is-
imparted by an eccentric or otherwise in order to produce the desired
amount of suction inside the knotter by the reciprocating motion of the
said cones. When more than one cone is employed a division plate or
diaphragm is fitted between them and is attached to the frame of the
knotter, an opening being left in the centre of the said plate sufficiently
large for the flow of the pulp through it. A stop in the form of an inner
projecting ledge or rib is also fixed to the inside of the knotter opposite
to the largest diameter of the double cones.
The spindle which carries the cones revolves along with the trunnions
which carry the knotter, and is passed at one end through one of the
trunnions, whilst its other end is supported in a bearing mounted on
vibrating springs attached to the end of the knotter, the said springs
yielding to the longitudinal vibrating motion of the cone spindle.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James M. Murray in the Great Seal Patent Office
on the 2nd May 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
M MURRAY, of the Royal Paper Mills, Wandsworth, in the County of
Surrey, Paper Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Second day of November, 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 James M. Murray, Her special license
that I, the said James McMurray, my executors, administrators, and
assigns, or such others as I, the said James Mc Murray, 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

page_text: vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
STRAINERS FOR STRAINING PAPER PULP," upon the condition (amongst others)
that I, the said James Mc Murray, my executors or administrators, by
an instrument in writing under my hand and seal, 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 ỲE, that I, the said James McMurray, do hereby declare
the nature of my 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 accompanying
Drawings, and to the letters and figures marked thereon, that is to
say :-
My said Invention relates to a peculiar construction and arrangement
of rotatory strainer for straining paper pulp, whereby a considerable
saving in the first cost of construction is effected, less power is required
for driving the same, its action is more regular and efficient, as no
"knots
can be formed by reason of the absence of rubbing surfaces
in contact with the pulp. The general arrangement is simple and not
liable to derangement, and the process of "washing up," as compared
with the ordinary knotter, is greatly facilitated.
"
"
The main body of my improved rotatory knotter or strainer consists
of a long rectangular hollow metal case, the sides of which are provided
with fine slits or perforations for straining the pulp, as in the ordinary
"knotter." This hollow perforated case consists of a skeleton frame,
each longitudinal bar of which is situate at one of the corners or angles
of the end plates of the "knotter or perforated case. The perforated
sides consist of a number of separate plates (three or more on each
side), which plates are each formed with projecting tongues at suitable
intervals along their opposite edges. These tongues engage under corre-
sponding tongues made at corresponding intervals along the inner faces
of raised fillets on each of the longitudinal corner bars of the frame.
The ends of the several perforated side plates, and the inner faces of the
end plates of the hollow perforated case are respectively tongued and
grooved so as to admit of their fitting accurately together when in
.

page_text: position. The side plates are easily inserted and removed by first
dropping them between the tongues on the fixed fillets, and then
sliding them home longitudinally so as to interlock the two sets of
projecting tongues. On removing these plates they are first slid back
horizontally till their projecting tongues come between the tongues
on the fillets, when they are free to be lifted out of the frame. The
several plates on each side or face of the "knotter" or hollow perforated
case are locked in position by a transverse perforated slide at one end
of the knotter, such slide being made to fit accurately by a tongue
and groove joint between the end of the last plate on the side and the
fixed end of the knotter. In order that these slides in the several faces
of the knotter may be retained in their places, and in their turn retain
the removeable perforated plates in position, one end of each slide is
made to project over the end of the next one, and the master slide, or
that which must first be removed before the rest can be withdrawn,
is secured in its place by a single screw, and thus one screw is made
to hold in place the whole of the plates and slides, in lieu of the great
number of screws which have heretofore been found necessary for this
purpose. A hollow trunnion is attached to each end of the knotter,
which trunnions work in bearings situate outside in lieu of inside the
vat as heretofore, hence the clogging up of the bearings by the pulp
becoming worked into them is entirely obviated.
Inside the above-described knotter there is or are placed one, two,
or more double truncated cones or pyramids, mounted axially upon a
central spindle, to which a rapid longitudinal reciprocating motion is.
imparted by an eccentric or otherwise in order to produce the desired
amount of suction inside the knotter by the reciprocating motion of the
said cones.
When more than one cone is employed a division plate
or diaphragm is fitted between them and is attached to the frame of
the knotter, an opening being left in the centre of the said plate
sufficiently large to allow of the flow of a portion of the pulp through
it, another portion of the pulp flowing between the outer edge of the
said diaphragm and the inside of the knotter plates. A stop in the form
of an inner projecting ledge or rib is also fixed to the corner bars inside
of the knotter opposite to the largest diameter of the double cones.
The spindle which carries the cones revolves along with the trunnions
which carry the knotter, and passes at one end through one of the
trunnions, whilst its other end is supported in a bearing mounted on

page_text: DL DEWTrays improveMENTS IN DERUINETS FOr Laper Laup.
vibrating springs attached to the inside of the end plate of the knotter,
the said springs yielding to the longitudinal vibrating motion of the cone
spindle.
And in order that my 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.
Figure 1 of my Drawings represents a longitudinal section of my
improved knotter in the pulp vat; Figure 2 is a transverse section
of the same taken along the line 1-2; Figure 3 is a similar view
taken along the line 3-4; and the rest of the Figures are enlarged
details, showing more clearly the mode of construction of the knotter.
A is the pulp vat in which the knotter B revolves, the hollow
trunnions C, C¹, of the knotter passing through shallow stuffing boxes
D, D¹, fitted to the outside of each end of the vat; E, E¹, are the two
bearings carried in standards outside the vat for supporting the weight
of the knotter, which is rotated by spur gearing engaging with the spur.
wheel F keyed on to the end of the trunnion C, or it may be rotated in
any other convenient manner.
The framing of the knotter consists of two end plates G, G¹, provided
with the before-mentioned hollow trunnions C, C¹, and connected at the
four corners by the longitudinal corner bars H, H, which are secured to
the end plates by screws a, as shown clearly in Figures 4 and 5. Each
bar has two longitudinal rebates or recesses 6 formed along it at right
angles to each other (see Figure 6) for the purpose of receiving the sides
of the main knotter plates I, I, two, three, or more of such plates being
employed to form each side of the rectangular shaped knotter. The slits
or perforations in these plates may be of the ordinary construction, but
in order to facilitate the insertion and removal of the said plates for
washing up or otherwise, and to secure them firmly in their places in the
knotter frame, I form a longitudinal rebate along each edge of the plates
(see Figure 7), and provide a number of projecting tongues c, c, of any
convenient length therein, leaving intervals or openings d between the
several tongues. On one side of the longitudinal rebate in the corner
bars H, I form other tongues or projections c³, c', of a length corres-
ponding to the intervals or openings d between the tongues c on the

page_text: knotter plates, or slightly less, the length of the intervals or openings d'
between the tongues c¹ on the corner bars being slightly greater than the
lengths of the tongues c on the knotter plates. When inserting the
knotter plates in the frame it is simply necessary to bring the tongues c, c,
thereon over the spaces d', d', on the bars and to drop the plate into the
rebates of the two bars on the same side of the frame, then by sliding
the said plate longitudinally along the said rebates the two sets of
tongues c and c¹ will become interlocked and the plate held fast. A
narrow groove at e is made in the inner face of the end plate G of the
knotter, with which a corresponding tongue on the end of the knotter
plate enters, when the said plate is slid home. The opposite end of the
same knotter plate has a similar groove made in it for the reception of a
corresponding tongue on the next plate when pushed home, and so on
throughout any number of knotter plates, thus preserving a perfectly
close joint between the end of the first knotter plate introduced and the
end plate of the knotter frame and between the adjoining ends of the
several knotter plates afterwards inserted.
In order to finally lock all the main knotter plates in their places after
they have been duly inserted and slid home I employ narrow knotter
plates I, I, which are slid in transversely between the ends of the last
plates inserted and the inner face of the end G¹ of the knotter frame.
tongues ff, being formed along the edges of the said transverse sliding
plates to enter corresponding grooves in the end of the last inserted
knotter plates and in the end G¹ of the knotter frame. These transverse
sliding plates act as locking plates, and they are so arranged that each of
the four transverse sliding plates round the knotter shall when slid home
transversely serve to lock the previously inserted plate I' in its place by
overlapping or entering a recess at 9 made in the rear end of such plate,
as shewn clearly on an enlarged scale in Figure 4. The transverse sliding
plate last inserted is secured in position by a single screw / passing
through the plate and into one of the corner bars (see Figure 4). By
removing this one screw the whole of the transverse sliding plates I can
be successively slid out, after which the large knotter plates I, I, can
also be readily removed by first sliding them back sufficiently far to
unlock the tongues c and c³, and then lifting them out of the rebates in
the corner bars H of the knotter frame.
g
In order to produce the requisite amount of suction through the per-
forated knotter plates, I place inside the knotter two or more double

page_text: cones or truncated cones K, K, mounted axially upon a central longitu-
dinal spindle L, which is supported at one end in a ring i secured to the
end of four radially disposed bent springs M, M, attached to the inner
face of the end plate G₁ of the knotter, such ring being secured in position
by nuts on the end of the spindle L. The opposite end of the spindle
works through a metal bush k inserted in the end of the hollow
trunnion C, and is connected by a collar N with the forked end of a
crank rod O, a portion of which only is shewn in Figure 1. This rod is
connected to a crank or eccentric having about a quarter or half an inch
throw, which imparts a rapid longitudinal reciprocating motion to the
spindle L and cones mounted thereon, whilst at the same time the said
cones and spindle revolve along with the knotter, the springs M allowing
of the longitudinal vibratory motion of the spindle L.
In order to prevent the strained pulp inside the knotter from gaining
access to the interior of the hollow trunnion C, I connect the end plate G
of the knotter with the end of the cone K by a short length of
India rubber or other flexible tubing, which is secured to projecting
bosses m, n, respectively secured to the inner face of the end plate G and
the end of the adjoining cone K, such tube allowing of the vibration of
the cones. Between the two cones I introduce a metal diaphragm P
secured at its corners to the inner sides of the four corner bars H, H, a
central aperture o being made in such diaphragm, and a clearance p left
between it and the under sides of the knotter plates I, to allow of the
free flow of the pulp from one part to the other of the knotter; a stop
frame Q is also fixed to the corner bars H, so as to surround the largest
part of each cone, and a pin or projecting rib q is made round this part
of each cone, leaving a clearance of about 3/8ths of an inch inside the
said stop frames, whereby the suction produced by the vibration of the
cones is increased.
Having now described and particularly ascertained the nature of my
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 :-
First. The construction and use of revolving knotters or strainers,
having their parts combined and arranged together substantially in the
manner and for the purpose herein-before described and illustrated by my
Drawings.

page_text: Second. The peculiar mode of securing the knotter or straining plates
to a knotter frame by interlocking tongues and transverse sliding locking
plates, as herein-before described and illustrated by my Drawings.
Third. The application and use of longitudinally vibrating cams dis-
posed inside a revolving knotter or strainer, substantially as and for the
purpose herein-before described and illustrated by my Drawings.
In witness whereof, I, the said James McMurray have to this my
Specification set my hand and seal, this Thirtieth day of April,
One thousand eight hundred and seventy-three.
JAMES MCMURRAY. (L.S.)