Improvements in Apparatus for Straining or Screening Paper Pulp.
Year: 1890

page_text: Date of Application, 11th Nov., 1890
Complete Specification Left, 11th Aug., 1891-Accepted, 11th Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Straining or Screening
Paper Pulp.
A communication from abroad by PETER R. THOM, of Appleton, in the County of
Outagamic and State of Wisconsin, United States of America.
I, WILLIAM PHILLIPS THOMPSON F.C.S. M.I.M.E. of the Agency for
Foreign Patent Solicitors 6, Lord Street Liverpool & 6, Bank Street
Manchester both in the County of Lancaster & 323 High Holborn in the County
of Middlesex Civil Engineer do hereby declare the nature of this invention to be
as follows:-
After paper pulp has been properly thinned in the mixing-box, it is run over
screens and strained through into a vat or vats beneath, in order that impurities,
lumps, shreds and sand, or anything which would injure the quality of the paper,
may be removed.
From the vat it is drawn off and taken to the wire.
In pulp-screens generally used nowadays one end of the screen
knocker-cams by which the screen is lifted vertically at that end, but not at the
supported upon
other end, and is therefore tipped and has besides the vertical, a horizontal motion
imparted to it, knocking it against the ends of the vat, jarring and wrenching the
frame or underlying vat and causing much noise. This horizontal motion is
unnecessary and in fact is undesirable and interferes with the perfectness of the
suction which is one of the accompaniments of the vertical movement, and also
tends to shake or jar through any shreds or lumps which have partly wedged
between the slits in the plates of the screen and to aid other shreds and lumps to
enter the slits. Another objection to the use of these knocker-cams is that there
may be lost motion, owing to imperfect wear, or to other causes.
It has been attempted also to make pulp-screens work in a strictly vertical line
by the use of eccentrics or of rock-shafts having cranks projecting horizontally, or
thereabouts, at the normal. Whenever an eccentric is used it must be revolved at
high speed to give the proper vibrations; whenever a rock-shaft with its cranks
spread horizontally is used, it can give but a single up and down movement for
ench oscillation.
The object of the present invention is to keep the screen permanently in a level
position and impart to it a strictly vertical movement, improving the suction and
obviating noise, besides obtaining a greater capacity and much cleaner stock,
avoiding the strings and lumps that were frequently passed through by the old
machine and lessening the wear and tear due to the horizontal movement in such
machine.
To this end the screens are mounted in boxes which slide in vertical guide-ways,
and raised by means of a link movement applied at the centre of each side of the
screen.
A suitable supporting frame preferably of metal carries a vat, above which is
placed a screen provided with screen-plates, as usual in this class of machines. One
or more vertical guide-brackets are strongly bolted to the sides of the vat and
receive closely fitting boxes in which short pintles from the screen are supported.
These boxes rest upon springs of rubber, or of any suitable construction, and are
permitted an up and down movement within their guides of about one eighth of
n inch, carrying the screen with them, but entirely preventing it from end wise
novement.
Mounted in bearings near the foot of the frame and centrally beneath the screen,
s a transverse shaft, having at each end two vertical crank-arms in line with each
ther, of exactly the same length, and vibrating to each side of the vertical. These

page_text: crank-arms have wrist-pins which support links, also of equal lengths, the upper
ends of these links being strapped to outsetting journals secured to the sides of the
screen at the exact longitudinal centre thereof.
Now it will be obvious that if the rock-shafts be oscillated, a toggle-movement
will be produced between the cranks and the links which will result in alternately
raising and lowering the screen in an exact vertical line, twice to each oscillation
of the rock-shaft, since the crank-arms will pass the dead centre in their to and fro
movement each time the shaft has a full oscillation. Therefore to one end of the
rock-shaft is secured an arm having a wrist-pin at its upper end, which, by means
of connecting-rods is coupled with a wrist-pin upon a disk carried by a rotating
driving-shaft. This driving shaft of course will be mounted in suitable bearings
It
and have power applied by means of a pulley or by any other suitable means.
will be evident now that when power is so applied, the rock-shaft at the foot of the
frame will be moved and the links alternately raised and lowered equally at each
end of the machine, carrying the screen up and down. In such movement of the
screen the elastic seats to its boxes will prevent any wear, shock or noise, while the
guide-brackets will prevent endwise movement and will keep it perfectly level
and true.
When it is desired to operate two screens at once, each will be mounted upon
links borne by cranks and transverse rock-shafts, precisely as in the before recited
manner. The cranks, however, beneath the screen will be connected by a coupling-
rod or bar and an additional transverse rock-shaft will be mounted in bearings, on
the same level as the bearings of the other shaft, and to one end of this latter rock-
shaft will be fixed the before mentioned actuating arm. This actuating arm will
be connected by a wrist-pin or by an intermediate crank and wrist-pin with the bar
which couples the operating cranks beneath the screens, the upper end of the
actuating arm will, as before, be coupled by a connecting-rod with the disk upon
the driving-shaft, so that when the actuating arm is moved, motion will be imparted
to both screens at once.
Dated this 10th day of November 1800.
WM. P. THOMPSON & Co.,
Agents for the Applicant.
Improvements in Apparatus for Straining or Screening
Paper Pulp.
A communication from abroad by PETER R. THOM, of Appleton, in the County of
Outagamie and State of Wisconsin, United States of America.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, and 6 Bank Street,
Manchester both in the County of Lancaster and 323 High Holborn in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
After paper pulp has been properly thinned in the mixing-box, it is run over
screens and strained through into a vat or vats beneath, in order that impurities,
lumps, shreds and sand or anything which would injure the quality of the paper,
may be removed. From the vat it is drawn off and taken to the wire.
In pulp screens generally used nowadays, one end of the screen is supported upon
knocker-cams by which the screen is lifted vertically at that end, but not at the other
end, and is therefore tipped and has besides the vertical, a horizontal motion imparted
to it, knocking it against the ends of the vat, jarring and wrenching the frame or
underlying vat and causing much noise. This horizontal motion is unnecessary and
in fact is undesirable and interferes with the perfectness of the suction which is one

page_text: of the accompaniments of the vertical movement, and also tends to shake or jar
through any shreds or lumps which have partly wedged between the slits in the
plates of the screen and to aid other shreds and lumps to enter the slits. Another
objection to the use of these knocker-cams is that there may be lost motion, owing
5 to imperfect wear, or to other causes.
It has been attempted also to make pulp-screens work in a strictly vertical line
by the use of eccentrics or of rock-shafts having cranks projecting horizontally, or
thereabouts, at the normal. Whenever an eccentric is used, it must be revolved at
high speed to give the proper vibrations; whenever a rock-shaft with its cranks
O spread horizontally is used, it can give but a single up and down movement for each
oscillation.
The object of the present invention is to keep the screen permanently in a level
position and impart to it a strictly vertical movement, improving the suction and
obviating noise, besides obtaining a greater capacity and much cleaner stock, avoiding
the strings and lumps that were frequently passed through by the old machine and
lessening the wear and tear due to the horizontal movement in such machine.
To this end, the screens are mounted in boxes which slide in vertical guide-ways,
and raised by means of a link movement applied at the centre of each side of the
screen, as will be hereinafter described.
In the drawings :-
Figure 1 represents, in side elevation, a single screen having the present
improvement applied thereto.
Figure 2 is a side elevation of a double screen constructed according to this
invention.
Figure 3, a top-plan view of said screen; and
Figure 4, an end elevation thereof.
A represents a metal supporting-frame for the superposed vat B, above which is
placed the screen C, provided with screen-plates C₁, as usual in this class of
machines. One or more vertical guide-brackets D are strongly bolted to the sides
of the vat and receive closely fitting boxes d, in which short pintles from the screen
are supported. These boxes rest upon springs of rubber, or of any suitable
construction, and are permitted an up and down movement within their guides of
about one-eighth of an inch, carrying the screen with them, but entirely preventing
it from endwise movement.
Mounted in bearings near the foot of the frame and centrally beneath the
screen, is a transverse shaft F, having at each end two vertical crank-arms F', in
line with each other, of exactly the same length and vibrating to each side of the
vertical. These crank-arms have wrist-pins, which support links G, also of equal
lengths, the upper ends being strapped to out-setting journals g secured to the sides
of the screen at the exact longitudinal centre thereof.
Now it will be obvious that if the rock-shafts be oscillated, a toggle movement
will be produced between the cranks and the links which will result in alternately
raising and lowering the screen in an exact vertical line, twice to each oscillation
of the rock-shaft, since the crank-arms will pass the dead centre in their to-and-fro
movement each time the shaft has a full oscillation. Therefore to one end of the
rock-shaft is secured an arm H, having a wrist pin at its upper end, which by
means of connecting rods J, is coupled with a wrist-pin k upon the disc K, carried
by the driving-shaft L. This driving-shaft of course will be mounted in suitable
bearings and for that purpose is shown as provided with journals I, but the bearings
hemselves have been omitted as unnecessary to an understanding of this invention.
Power may be applied to this driving-shaft by means of a pulley M, or by any
ther suitable meana. It will be evident now that when power is so applied, the
ock-shaft at the foot of the frame will be moved and the links alternately raised
nd lowered equally at each end of the machine, carrying the screen up and down.
n such movement of the screen, the elastic seats to its boxes will prevent any
ear, shock or noise, while the guide-brackets will prevent end wise movement and
ill keep it perfectly level and true.

page_text: When it is desired to operate two screens at once, each will be mounted upon
links borne by cranks and transverse rock-shafts, precisely as in the before recited
manner and as indicated in the 2nd and 3rd figures of the drawings.
The cranks, however, beneath the screen will be connected by a coupling rod or
bar N, and an additional transverse rock-shaft II will be mounted in bearings o,
and on the same level as the bearings of the other shaft, and to one end of this
rock-shaft will be fixed the before mentioned actuating arm. This actuating arm
will be connected by a wrist-pin p, or by an intermediate crank P and wrist-pin p*
with the bar which couples the operating cranks beneath the screens, the upper
end of the actuating arm will, as before, he coupled by a connecting-rod with the
disc upon the driving-shaft, so that when the actuating-arm is moved, motion will
be imparted to both screens at once.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. The combination substantially as hereinbefore set forth, of the vat, the pulp-
screen, vertical guides for said screen at each side thereof and near its ends, a
transverse rock-shaft centrally beneath the screen and provided with vertical crank-
arms at each side of the frame, vibrating to each side of the vertical, links con-
necting said cranks to journals from the centre of the screen, and means for
oscillating said rock-shaft.
2. The combination, substantially as hereinbefore set forth, of the vat, two or
more screens mounted therein, vertical guides for said screens at each side thereof,
transverse rock-shafts, centrally beneath each screen provided with crank-arms at
each end, a rod connecting the cranks of each rock-shaft at one side of the
supporting frame, links connecting each crank with the centre of the respective
screens and means for reciprocating said rod.
3. The combination, substantially as herein before set forth, of the vat, the
superposed screen, the vertical guide-brackets, the elastic cushions therein, and the
boxes sliding in said guide brackets and carrying the screen.
4. The combination, substantially as hereinbefore set forth of the vat, the screen,
the vertical guides at each side of the screen, the transverse rock-shaft centrally
beneath the screen, the crank at each end of the rock-shaft, the links connecting
said cranks with journals from the centre of the screen, the actuating arm fixed to
said rock-shaft, the driving shaft and its disc, and the connecting-rod coupling a
wrist-pin upon said disc with a wrist-pin upon the upper end of the actuating arm.
Dated this 10th day of August 1891.
WM. P. THOMPSON & Co.,
Agents for the Applicant.