Year: 1887

page_text: Date of Application, 18th June, 1887
Complete Left, 10th Mar., 1888
Complete Accepted, 13th Apr., 1888
We, JOHN WOOD, of 82 Leith Walk, and ROBERT WOOD, of 4, Ferrier Street,
both in Leith, in the County of Mid Lothian, North Britain, Engineers, do hereby
declare the nature of this Invention to be as follows, that is to say:
Our said Invention relates to pulp-straining apparatus of the kind in which the
pulp is, by a pulsating action, drawn through strainer plates fixed on the sides of a
rotating casing, the pulp passing through being delivered through a hollow trunnion
at one end of the rotating casing.
These rotating strainers have usually been made with four sides, but we have
observed that the action with each side is most effective when the side is uppermost
and horizontal, the action being much less with the plates when undermost, owing to
the tendency of the pulp to fall away by its gravity. By our Invention we make a
very effective machine and one which is much less costly (the strainer plates being the
most costly part of the machine) by making the rotating strainer or casing with three
sides only. The rotation of the three-sided casing may be effected in the ordinary
way, or the gearing may be constructed so that the motion is slower when each side
is uppermost and horizontal than during the interval when a side is moving into that
position.
The pulsating action is produced by a pump acting on air through a hollow trunnion
at the end opposite to that at which the strained pulp is delivered. The trunnion
through which the air works has connected to it a bag of rubber or a casing with
rubber sides through which the pulsating action is communicated to the pulp inside
of the rotating strainer. It is difficult to prevent leakage of water into the interior
of the pulsating bag or casing and when there is an accumulation of water therein the
action is rendered imperfect. We prevent any such imperfect action arising from a
little leakage by placing one or more small scoops within the pulsating bag or casing
TD 077

page_text: at a point or points as distant as possible from the axis so that when any scoop is in
its lowest position any water will drain into it. In connection with each scoop there
is a pipe or passage leading into the hollow trunnion, and when by the rotation each
scoop gets to its highest position the water it may have taken up will drain through
the pipe or passage into the trunnion. The trunnion is shaped internally so that any
water delivered into it finds its way out at the end into a space beneath the pump from
which space it may be withdrawn periodically through a stopcock.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Straining Paper Pulp and the like.
We, JOHN WOOD of 82 Leith Walk, Leith, in the County of Mid Lothian, North
Britain, Engineer, and ROBERT WOOD, formerly of 4 Ferrier Street, Leith, aforesaid,
but now of 12 Green Street East, Darwen, in the County of Lancaster, 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, that is to say :-
Our said Invention relates to pulp-straining apparatus of the kind in which the pulp
is, by a pulsating action, drawn through strainer plates fixed on the sides of a rotating
casing, the pulp passing through being delivered through a hollow trunnion at one
end of the rotating casing.
These rotating strainers have usually been made with four sides, but we have
observed that the action with each side is most effective when the side is uppermost
and horizontal, the action being much less with the plates when undermost owing to
the tendency of the pulp to fall away by its gravity. By our Invention we make a
very effective machine and one which is much less costly (the strainer plates being
the most costly part of the machine) by making the rotating strainer or casing with
three sides only. The rotation of the three-sided casing may be effected in the
ordinary way, or the gearing may be constructed so that the motion is slower when
each side is uppermost and horizontal than during the interval when a side is moving
into that position.
The pulsating action is produced by a pump acting on air through a hollow
trunnion at the end opposite to that at which the strained pulp is delivered. The

page_text: trunnion through which the air works has connected to it a bag of rubber or a casing
with rubber sides through which the pulsating action is communicated to the pulp
inside of the rotating strainer. It is difficult to prevent leakage of water into the
interior of the pulsating bag or casing and when there is an accumulation of water
therein the action is rendered imperfect. We prevent any such imperfect action
arising from a little leakage by placing one or more small scoops within the pulsating
bag or casing at a point or points as distant as possible from the axis so that when
In connection with
any scoop is in its lowest position any water will drain into it.
each scoop there is a pipe or passage leading into the hollow trunnion, and when
by the rotation each scoop get to its highest position the water it may have
taken up will drain through the pipe or passage into the trunnion. The trunnion
is shaped internally so that any water delivered into it finds its way out at the
end into a space beneath the pump from which space it may be withdrawn periodically
through a stopcock.
And in order that our said Invention and the manner of performing the same
may be properly understood we hereunto append a sheet of explanatory drawings
showing a simple and convenient modification of our improved pulp-straining
apparatus.
Figure, 1, on the accompanying sheet of drawings is a sectional side elevation, and
figure, 2, is a transverse section of our improved apparatus. Figure, 3, is a sectional
end elevation showing gearing for imparting varying speed to the rotating strainor.
In these drawings the same reference numerals are used to mark the same or like
parts wherever they are repeated.
The rotating strainer, 4, is made with only three sides but is otherwise of the usual
construction, being constructed with hollow trunnions, 5, 6, which pass through stuffing
boxes, 7, 8, in the ends of the vat, 9. One, 5, of these trunnions serves for the delivery
of the strained pulp into the service-box, 10, and the other, 6, communicates through
another stuffing box, 11, with the interior, of the pump, 12. The trunnion, 6, has
fixed on it a spurwheel, 13, of varying radius and gearing with a similar spurwheel, 14,
on a second-motion shaft, 15, which receives its motion by a worm, 16, and worm-
wheel, 17, from any suitable source. The action of the spurwheels, 13, 14, is such as
to cause the rotation of the three-sided strainer, 4, to be slower when each side is
uppermost and horizontal than during the interval when a side is moving into that
position, this varying motion rendering the action of the strainer, 4, more effective as
hereinbefore described.
The pulsating action is produced by a pump, 12, acting on air through the hollow
trunnion, 6, which trunnion has connected to it one end of a bag, 18, of rubber the
other end of which is closed by a plate, 19, connected to and supported by brackets, 20,
formed or fixed on the inside of the rotating strainer, 4. The central part of the
bag, 18, is occupied as usual by a closed shell or box, 21, of wood or other suitable
material to diminish the quantity of air required inside the bag, 18, through which
the pulsating action is communicated to the pulp inside the rotating strainer, 4. One
end, 22, of the box, 21, is tapered and rounded and the box, 21, and bag, 18, are of a
similar form to the rotating strainer, 4, as seen in figure, 2. To prevent imperfect
action arising from any leakage of water into the interior of the bag, 18, which may
take place a small scoop, 23, is fixed at one end of the strainer, 4, so as to extend
inside the bag, 18, at one of its corners and when the scoop, 23, is in its lowest position
water will drain into it. A pipe, 24, leads from the scoop, 23, through the hollow
trunnion, 6, and when by rotation the scoop, 23, gets into its highest position the
water in it will drain into a space, 25, beneath the pump, 12, from which space it may
be withdrawn periodically through a stopcock, 26.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed we declare that what we
claim is :-
1. The improved combination of parts of apparatus for straining paper pulp and
the like substantially as hereinbefore described.

page_text: 2. Making rotating strainers of pulp straining apparatus with only three sides
substantially as and for the purposes herein before described.
3. The imparting of varying motion to rotating pulp strainers substantially as and
for the purposes hereinbefore described.
4. The removing of water from the interior of the pulsating bag used in pulp
straining apparatus by a scoop within the bag and a draining pipe leading therefrom
substantially as herein before described.
EDMUND HUNT,
Applicants' Agent.