A New or Improved Method and Apparatus for Separating or Sorting Chips Used in the Manufacture of Wood-pulp, and Preparing them for the Digestor.
Year: 1896

page_text: Date of Application, 13th Mar., 1896-Accepted, 11th July, 1896
COMPLETE SPECIFICATION.
A New or Improved Method and Apparatus for Separating or
Sorting Chips Used in the Manufacture of Wood-pulp, and
Preparing them for the Digestor.
A communication by NATHANIEL MORRISON JONES and REGINALD STOWELL
TALBOT, both of Lincoln, in the County of Lincoln and State of Maine,
United States of America, Manufacturers of Paper-pulp.
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, 118 New Street, Birmingham in
the County of Warwick and 31 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:-
This invention relates to the method of and apparatus for separating or sorting
chips used in the manufacture of wood-pulp, such chips containing a considerable
portion of waste matter, unfit for pulp and composed chiefly of fragments of knot
wood which is very dense and filled with resinous matter.
The invention has for its object, first, the rapid, complete and simultaneous
moistening of the perfect or selected chips preparatory to the cooking in a digestor,
so they may the more rapidly absorb the acid and steam; and secondly, the
convenient and ready separation of the selected chips from the dirt and other
objectionable matter.
Heretofore it has been common to subject the chips to the action of steam at low
pressure, to moisten them; but this practice has been found to possess some
objectionable features, one being that the process is a slow one, another that the
action of the steam is not readily controllable, owing to the necessarily low
pressure employed, and another that the chips are necessarily in a more or less
compact mass, so that some portions of the chips do not receive the proper moisture
from the steam.
This invention, in one of the steps of the method, utilizes one of the agencies of
nature for the practical purpose of quickly and equally moistening wood-chips,
owing to the fact that the clear-wood chips, when submerged in liquid, such as
water, will rise to the top thereof. This immersion of the chips and their
subsequ. nt passage through the water, owing to the difference in the specific
gravities of the wood and water results in the chips becoming separated from each
other to such extent that all portions of their surfaces will become quickly and
uniformly moistened, the water also penetrating the pores of the wood completely,
owing to the chips being, in practice, of small size.
This latter action, however, occurs only in connection with the clear-wood chips,
while those made wholly or principally from the knotty portions contain so much
resinous matter that they not only do not absorb water but they also fail to rise to
the top of the liquid with the clear-wood chips, and they therefore become
separated from the latter. They are, in fact, of such relative specific gravity that
they fall to the bottom of a body of water, together with the dirt and other
relatively heavy objectionable matter, and thus become separated from the clear-
wood chips, the latter rising to the top of the body of liquid, from which they may
be renoved by hand or by some suitable form of apparatus, in a thoroughly
moistened condition, ready for "cooking" in the digester.

page_text: accompanying drawings forming a part of this specification.
Figure 1 represents a longitudinal section of an apparatus embodying the
invention.
Figure 2 represents a section on line 2-2 of Figure 1, looking towards the
right.
Figure 3 is a plan view of the parts below the line 3-3, Figure 1.
The same letters of reference indicate the same parts in all of the figures.
In the drawings a represents a tank, and b represents a rotary agitator or striker
which extends across the upper portion of the tank and is preferably composed of
a shaft and a series of independent arms radiating therefrom, the arms being
thickly arranged, so that when the agitator is rapidly rotated they will strike
practically all points along a line extending across the surface of a body of liquid c
contained in said tank the liquid extending to such height that the downwardly
projecting arms of the agitator enter the liquid. The agitator is so arranged that
it subdivides the surface of the liquid into a chip-receiving area and a chip-
delivering area. The chips are deposited in a mass in the chip-receiving area, and
are attacked by the agitator and forcibly scattered and submerged, the agitator
moving in the direction indicated by the arrow marked thercon. The agitator
therefore moves the liquid at and near the surface of the body c in such a direction
as to cause it to carry the chips into the chip-delivering area and cause them to
encounter the chip-elevator hereinafter described. The knot-wood chips and other
heavy matter, all of which will hereinafter be termed waste, have a tendency to
sink in the liquid, this tendency being increased by the moistening caused by the
forcing of the chips into the liquid by the agitator.
represents a waste-conveyor upon which the descending waste is deposited,
said conveyor being preferably an endless band provided with slats e and
supported by rolls or sprocket wheels ee, to which motion is imparted in any
suitable way. The conveyor e extends under the chip-receiving and delivering
areas and delivers the waste into the upper end of an inclined spout or chute to a
waste elevator g, which is an endless band running upon rolls or wheels gl g² and
arranged at a suitable angle so that it is adapted to raise the waste from the tank
and drop it into a waste conveyor g³ at one end of the tank, said conveyor having
a screw 9* or other means for progressively removing the waste that is deposited
in it.
i, represents a chip elevator, composed of an endless band, preferably of wire
cloth, supported by rollers or wheels i, 2, and arranged at an incline, the lower
portion of said chip elevator being at one end of the chip-delivering area of the
body of liquid, so that it receives the chips from said area and elevates them,
finally discharging them upon a conveyor, by which they may be removed to a
hopper k, which may be arranged over a shaker adapted to separate the free liquid
from the chips.
To insure the maintenance of an effective current by the agitator, a false bottom
or partition m, is provided below the upper portion of the conveyor e, said partition
extending across the tank, and constituting a barrier between the water composing
the chip-receiving and delivering areas and the water in the space below said areas,
so that a horizontal current moving continuously in one direction is maintained in
the chip-receiving and delivering areas, and eddies and counter currents in said
areas are prevented.
There is a sufficient communication between the end portions of the space
below the waste conveyor and the receiving and delivering areas to permit water
to flow downwardly, at x, and upwardly at a', the water returning from the outer
end of the delivering area under the false bottom of the outer end of the receiving
area.
One side of the spout f, is extended upwardly at f¹ sufficiently to prevent pieces
of waste matter from coming in contact with the chip-elevator. A casing into
which the spouty delivers its contents encloses the upwardly moving portion of
the waste elevator, and prevents the same from forming a current in the main body

page_text: of liquid, the object of this arrangement being to prevent currents which will
conflict with the current formed by the agitator as indicated by the arrow marked
on the liquid in Fig. 1. Said casing ensures the presence of a body of dead water
in the spout, so that there is no downward movement of water in said spout
sufficient to draw down floating chips from the delivering area.
It will be seen that the construction above described particularly the false
bottom end of the spout, f1 and the casing f insure an effective movement of the
water in the receiving and delivering area of the tank by the action of the
agitator, the water in said areas being shut off from the main body of water to
such an extent that the agitator moves all the water above the waste conveyor e,
in one direction and is therefore enabled to deliver the chips with certainty to the
chip-elevator.
The chip-elevator being made of wire cloth and arranged to a great extent over
the tank, enables the principal part of the water to be drained from the chips,
while they are being elevated. It is preferred to provide a sheet metal gutter o,
arranged to guide the water falling from the chip elevator back into the tank.
The spout is preferably made tapering from its upper end to its lower end, the
latter as well as the casing and waste elevator g, being comparatively narrow.
The object of making the waste elevator narrow is to make it lesa bulky and
heavy and enable it to be operated with less power. The proportion of waste is
comparatively small so that the waste elevator does not require to be made so wide
as the chip-elevator.
The chip-shaker as here shown consists of a series of screens p, p', p² each
having a wire cloth bottom. The bottom of the top screen being of a coarser
mesh than that of the second screen, which in turn is of coarser mesh than the
bottom of the third screen. The screens are inclined and rest upon a frame
work 2, upon which the bottom screen is adapted to slide. The screeus may be
rapidly reciprocated by means of a connecting rod or pitman r, connected suitably
to a driving shaft. The chips are assorted as to size by the different screens.
The screens p, p, and p are provided with delivering spouts p, p, p respectively,
to deliver the chips into different receptacles.
A rotary agitator p is adapted to stir the chips and prevent their close packing
in the screen p', said screen having a solid plate p' to support the chips under the
agitator.
s, represents a steam coil located in the tank at or near the botton thereof, its
object being to heat the water and thereby cause it to liberate the resinous matter
from the chips before they go to the digester.
f5 represents a strip of flexible material such as rubber belting affixed to the
upper edge of the spout, and bearing yieldingly against the under portion of the
waste conveyor e, as a means for preventing the water from carrying waste
matter under the conveyor e, and also as a scraper to remove pieces of waste
that may adhere to the conveyor. The current generated by the agitator passes
over the portion of the spout 1, through the meshes of the chip-elevator, and
from thence downwardly and then backwardly, through the spaces 4/4
(Figure 2) between the spout and the sides of the tank.
In Figure 3, a plan view of the waste conveyor and the false bottom is shown,
the ends of the false bottom, being shown as recessed to receive the rolls e,
supporting the waste conveyor. Extensions m of the false bottom project between
the ends of said rolls and the sides of the tank. Vertical partitions m exte id
downwardly to the ends of the strip, to prevent water from flowing downwanlly
from the delivering area and between the false bottom and the spout.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondents, I declare that what I claim is :-
1. The improved method of simultane usly moistening and sorting the clear
wood-chip from a mass of chips for cooking in a digester, the process consisting in

page_text: positively and completely submerging the mass in a liquid of greater specific
gravity than the clear wood chips; then permitting the clear wood chips
individually to scatter and rise through the liquid to the surface thereof, and
allowing the knotty chips and other refuse of the mass to remain at the bottom.
2. A chip assorting apparatus comprising a tank, a body of liquid therein, a
rotary agitator or striker subdividing the surface of the liquid into a chip-receiving
and a chip delivering area, said agitator forcibly submerging chips floating on the
receiving area and permitting the submergel chips to rise into the lelivering area,
and a conveyor arranged to remove floating chips from said delivering area, the
agitator and conveyor being separated by a space sufficient to permit the lighter
chips to rise without interfering with the settling of the heavier chips.
3. A chip assorting apparatus comprising a tank, a body of liquid therein, an
agitator or striker extending across the tank and sublividing the surface of the
liquid into a chip receiving and a chip delivering area, a substantially horizontal
submerged convey or located below said area, and adapted to receive and feed
forward knots or waste matter that sinks in the liquid, a spout or chute at the
delivering end of said conveyor, and a waste elevator arranged to receive matter
from said spout.
4. A chip assorting apparatus comprising a tauk, a body of liquid therein, an
agitator or striker extending across the tank and subdividing the surface of the liquid
into a chip receiving and a chip delivering area, a substantially horizontal
submerged conveyor located below said areas, and adapted to receive and feed
forward knots or waste matter that sinks in the liquid, a spout or chute at the
delivering end of said conveyor, a knot elevator arranged to receive the knots
from said spout and a chip elevator communicating with the chip delivering area of
the liquid.
5. A chip assorting apparatus comprising a tank, a body of liquid therein, an
agitator or striker extending across the tink and subdividing the surface of the
liquid into a chip receiving and a chip delivering area, a substantially horizontal
submerged conveyor located below said areas, and adapted to receive and feel
forward knots or waste matter that sinks in the liquid, a spout or chute at the
delivering end of said conveyor, a waste elevator arranged to receive knots from
said spout, and a waste conveyor, arranged to receive matter from said elevator.
6. A chip assorting apparatus comprising a tauk, a body of liquid therein, an
agitator or striker extending across the tank and subdividing the surface of the
liquid into a chip receiving and a chip delivering area, a substantially horizontal
submerged conveyor located below said area and adapted to receive and feed
forward knots and waste matter that sinks in the liquid, a spout or chute at the
delivering end of said conveyor, a knot elevator arranged to receive the knots from
said spout, a chip elevator communicating with the chip delivering area of the
liquid and a chip conveyor arranged to receive chips from chip elevator.
7. A chip assorting apparatus comprising a tank, a body of liquid therein, an
agitator or striker extending across the tank and subdividing the surface of the
liquid in to a chip receiving and a chip delivering area, a substantially horizontal
submerged conveyor located below said areas, and adapted to receive and feed
forward knots or waste matter that sinks in the liquid, a spout or chute at the
delivering end of said conveyor, a waste elevator arranged to receive knots from
said spout, a waste conveyor, arranged to receive matter from said elevator, and a
chip shaker arranged to receive chips from the chip conveyor.
8. A chip assorting apparatus comprising a tank, a body of liquid therein, an
agitator or striker extending across the tank and subdividing the surface of the
liquid into a chip receiving and a chip delivering area, a substantially horizontal
submerged conveyor located below said areas, and adapted to receive and feed
forward knots or waste matter that sinks in the liquid, and means for guiding the
liquid horizontally through said chip receiving and delivering areas.
9. A chip assorting apparatus comprising a tank, a body of liquid therein, an
agitator or striker extending across the tank and subdividing the surface of the

page_text: liquid into a chip receiving and a chip delivering area, a substantially horizontal
submerged conveyor located below said areas, and adapted to receive and feed
forward knots or waste matter that sinks in the liquid, and a partition or false
bottom under the said receiving and delivering areas, said partition being arranged
to permit liquid to flow from the delivering end of the delivering area, downwardly
to the space below the false bottom, and from said space upwardly into the
receiving end of the receiving area, and to maintain a horizontal progressive
current between said ends.
10. A chip assorting apparatus comprising a tank, a body of liquid therein, an
agitator or striker extending across the tank and subdividing the surface of the
liquid into a chip receiving and a chip delivering area, a substantially horizontal
submerged conveyor located below said areas, and adapted to receive and feed
forward knots or waste matter that sinks in the liquid, a partition or false bottom
under said receiving and delivering areas, a foraminous chip elevator at one end of
said elevating area, a waste elevator below the chip elevator, a casing enclosing
the operative part of the waste elevator, and a spout or chute connected with
said casing and arranged to receive gravitating matter from the waste conveyor.
Dated this 12th day of March 1896.
WM. P. THOMPSON & Co.,
Agents.