IMPROVEMENTS IN RAG ENGINES FOR BEATING PAPER PULP
Year: 1886

page_text: I JOHN HENRY HORNE of Lawrence, in County of Essex, State of Massachu-
setts, United States of America, machinist, do hereby declare the nature of my
invention for "IMPROVEMENTS IN RAG ENGINES FOR BEATING PAPER PULP" 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 improvements in rag-engines, which are employed in
pulping fibrous material, prior to its being converted into a thin continuous sheet
in the process of making paper; such engines are usually composed of a tub or vat
having straight sides, semi-circular ends, and longitudinally divided by a partition
or mid-feather.-Within the tub is located a beating-roll armed with a series of
peripheral bars or cutters and a bed-plate, likewise furnished with knives, the two.
cooperating together and compelling the stock in process of beating to travel
continuously around and within the tub, pass between the stationary and revolving
knives and thereby be reduced to pulp for the purpose above premised.
One great difficulty hitherto in the construction of these engines, whatever may
be the path of travel given to the material contained in them, consists in the fact,
that the various fibres or bunches of fibre, after being placed within the engine,
maintain concentric paths of movement with respect to each other. Thus a piece
of stock, located near the sides of the tub or one placed near the mid-feather will
continue to travel in concentric paths until the engine is emptied; except in case
manual labor is applied with a paddle to disturb their courses and compel them to
deviate therefrom.
.
Hence it is obvious that the fibre travelling the more rapidly will be reduced
more quickly and the "stuff" is of uneven quality.
My invention relates primarily to the especial form and cross-section of the
tub; secondly, to the arrangement and construction of the back-fall and thirdly,
to the position of the screen and the manner of washing the stock while being
operated upon in the engine.-The essential object of my invention is to effect a
change in the course of the material in the engine automatically and obliquely to
the longitudinal axis of the engine during each complete passage thereof around the
tub, and thereby thoroughly mix the stock. Thus the particles, which are nearest
the mid-feather in one passage about the tub and which therefore travelled the
fastest are directed and changed obliquely across the engine prior to their passage
about the roll and hence they will emerge and are located near the side.-Such

page_text: stock will consequently travel the slowest during the next passage around the tub,
since it remains contiguous to the retaining walls of the tub.
This mixing and stirring of the material within the tub is effected primarily by
the shape of the tub in cross section, the width of which is equal to the active face
of the roll, the latter located in one end thereof. Thus to effect the desired change
in the path of movement of the stock, the proportions of the tub are altered and
in cross section the two passages formed in the tub by the mid-feather are twice as
deep, as they are wide. Again the stock is permitted to fill the entire width of the
engine just prior to its entrance beneath the roll and also immediately after leaving
the same. Hence the mid-feather terminates a short distance before reaching the
roll and the stock, as it approaches the latter as before premised, is permitted to
spread out and fill the entire width of the engine.
In other words in its course about the mid-feather, the stock as a body may be
said to have a vertical position, though travelling horizontally, until the termination
of the mid-feather allows it to spread out and assume a horizontal position. The
movement or path of travel of the stock can be most aptly compared to the
direction and course taken by a cross-belt in travelling between two pulleys, one
horizontally and the other vertically disposed.
After the passage of the stock between the roll and the bed-plate, the particles
composing it are directed upon and over the back-fall, which here extends entirely
across the engine, but contracts as it extends away from the roll, until it unites
with the mid-feather, whence it is continued downward, between the latter and the
side of the engine to the bottom of the tub. This contraction of one half its width
again restores the mass of stock to a general vertical position and the latter is so
maintained until just prior to its return passage beneath the roll.
Thus it will be evident that the fibres composing the material in process of
being pulped can not travel in continuous concentric paths of movement, but are
changed and forced obliquely of the engine, whereby, a thorough mixing of the
stock is automatically effected.
The drawings accompanying this specification represent in Fig. 1 a plan, and
Fig. 2 a sectional elevation of an engine for beating paper-pulp embodying my
improvements.-In Fig. 1 the cap or cover is removed from the roll. Fig. 3 is a
. cross-section of the engine-tub on line, of Fig. 1, looking in direction of
arrow 1; while Fig. 4 is a similar section on line y y in direction of arrow 2.
In said drawings A represents an engine-tub composed of the bottom B,
sides Ċ C and semi-circular ends D D¹; said tub being longitudinally provided
with a mid-feather E, which does not extend close to the face of the roll F; the
latter being located in the extreme end of the tub, and mounted upon and driven
by the shaft G.-From the cross-section of the engine, shown in Figs. 3 and 4, it
will be seen that the proportions of the tub are materially altered from those
hitherto employed in machines of this class. Thus the material as a body, is
vertically disposed, but travels in general horizontal paths of movement; this
vertical position is maintained the entire length of the mid-feather upon each side
thereof; or from the point of juncture of the back-fall with the bottom B to where
the mid-feather terminates in front of the roll.
The tub is divided by the mid-feather E into a U shaped channel formed by the
passages a a¹, which I term the supply and discharge respectively. Now in the
arrangement shown it is evident that the two currents of stock approaching and
leaving the roll must be kept separate and distinct, and furthermore to obtain
the full benefit of the active surface of said roll, the stock must be spread out
before passing between it and the bed-plate S, on the under side of the roll; while
upon the top side of the latter or when the material emerges and leaves it, an
opposite converging effect must be produced to return said stock to its confined
discharge passage a¹.
To effect this object I have constructed a back-fall H, which is disposed as usual,
sloping away from the roll and tightly fits the passage a¹ as shown; this back-fall
extends entirely, across the tub by means of the triangular piece b, the upper edge

page_text: of which is in close proximity to the periphery of the roll, see Fig. 2-But this
-back-fall now only partially prevents the flow of stock leaving the beating roll
from entering the supply passage a and opposing the flow of stock towards said
roll; therefore I have provided and disposed a partition c, or deflector-plate, which is
not only angularly disposed with respect to the longitudinal axis of the roll, but is
obliquely situated as to the bottom of the tub, while the upper edge is flush with
the top sides of the latter and the mid-feather.
Thus the position of this deflector plate c serves two purposes; located at the
termination of the passage a and sloping obliquely towards the bottom of the roll,
when the stock approaches and impinges against the under side of said plate, the
material is deflected, crowded downwards and rapidly passes into the chamber d
extending beneath the back-fall H; this chamber, as before stated, being of
the full width of the engine. Thus stock, close to the mid-feather, when
entering the chamber d is crowded towards and spreads to the back side C¹, passes
under the roll and emerges and continues its course near the side of the tub C¹,
where its motion is now very slow.
The second purpose effected by the deflector plate c is in converging and
directing the material, as it passes from the roll, downwards and compels it to
enter the discharge passage a'; gradually changing the general position of the
mass from a horizontal plane, while passing around the roll, to a vertical plane
during its passage around and about the mid-feather.
Thus it is very evident that the stock by this arrangement is thoroughly mixed
and its circulation changed at each successive complete passage about the tub, and
it is apparently impossible for any fibre or lock of fibres to maintain the same path
of travel during two successive passages; and therefore to those conversant in the
process of pulping, it is equally clear that the stock will be more evenly reduced,
hence less time is required in emptying an engine since by the methods heretofore
practised the entire contents must be retained until the longest fibres have been
properly reduced.
In connection with the engine I have introduced a washer, which is located in a
convenient place beneath the back-fall; this washer consists of a reticulated plate
or screen of fine wire e, angularly but vertically disposed within the tub as shown
in Fig. 1-This screen is arranged to extend behind the mid-feather and is thereby
protected from the rush of stock about the end of the mid-feather, which might
tend to injure or destroy it. The water supply enters at f, while the discharge
is shown at g; the valve h admitting and the valve i discharging more or less
water to suit the requirements, either to wash out and remove the superfluous
chemicals, or to render the contents of the engine thick or thin.
In emptying the engine it will doubtless be found very convenient, if not
necessary, to cleanse the chamber d, in which case the valve i is closed, while the
intermediary valve; is open; thus water is free to flow into the engine by the
pipe k through the screen e and thoroughly remove any fine pulp, which may
remain in or about the roll and bed-plate.
The operation of this engine is as follows:-the roll being properly adjusted
with respect to the bed-plate, water is admitted and the requisite amount of
fibrous material or "half stock" is then supplied.-The stock is now advanced by
the suction caused by the roll, towards the latter and as it strikes the deflector-
plate c it is crowded downwards and then suddenly allowed to spread out the
entire width of the engine and enter in a horizontal position between the bed-plate
and the roll at all points; thus the entire face of the roll is active. The stock
is carried up and about the roll and is discharged therefrom upon that part of the
back-fall, contiguous to the knives of the roll and which here extends the entire
width of the tub. Upon delivery on this back-fall said stock is directed and
impelled by the back-fall and upper surface of the deflector-plate o towards and
into the passage a', where the general position assumed by the mass of fibre is
vertical.

page_text: Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed, I declare what
I claim is :-
1. In a rag-engine a pulp way in combination with a beater-roll, a bed-plate
and a mid-feather arranged in said tub, the latter being provided with passages of
uniform capacity in any cross-section, said passages being of such shape that the
pulp approaches the roll in a body of greater height than width, and immediately
before reaching the roll is converted into a body of greater width than height but
returns to its first condition after passing over the roll, the result being that the
moving column of pulp is given a spiral motion, substantially as set forth.
2. The improvement in rag-engines consisting in a tub, containing a beater-roll
and its cooperating bed-plate, located in one end of the tub, in combination with
said tub, which is longitudinally divided by a mid-feather into two passages, in
width equal to one half the active face of the roll or thereabouts, but at their
termination contiguous to the face of the roll equal in width to the latter, sub-
stantially as described.
3. In a rag-engine a tub baving a mid-feather, in combination with a beater-roll
arranged in said tub at one end thereof, said mid-feather dividing said tub, as
shown, and thereby forming a channel, which is U shaped for the greater part of
its length and leaving a space between the end of the mid-feather and said roll
and which is of the entire width of the tub, substantially as set forth.
4. A rag-engine composed of the beater-roll with its co-operating bed-plate,
located at one end of the vat, and the vat, longitudinally divided by the mid-
feather and back-fall into a channel, which is U shaped for the greater part of its
length, the body of which in cross-section is one half the width of the tub, while
the ends thereof, terminating in front of the roll are the full width of the vat,
· substantially as herein stated.
5.-The combination with the bed-plate, a beating-roll, the active face of which
is equal to the width of the engine and the tub in which they operate upon the
stock circulating substantially in horizontal paths of movement, of the back-fall
extending across the upper part of the tub and in front of the roll, whereby the
stock passing beneath and partially around the roll is concentrated and directed
within a passage but half the width of the tub, substantially for purposes set
forth.
'
6. The improved vat for paper-pulp engines composed of the retaining wall CC¹
D D¹, the mid-feather E terminating some distance from the face of the roll, the
back-fall H with its portion b extending across the vat in front of the roll, and the
deflector-plate c, all operating substantially as described.
7. In combination with a rag-engine the washer e, formed beneath the back-
fall and provided with a reticulated plate, substantially for purposes herein stated.
8.The combination with the inlet-pipe k and the valves ij, of the tub A and
its washer e, located substantially as herein stated and operating for purposes set
forth.
samanth dow of July AD 1886.