Improvements in Machines for Pulping Up Paper and Paper Materials.
Year: 1899

page_text: Date of Application, 30th May, 1899-Accepted, 16th Sept., 1899
COMPLETE SPECIFICATION.
Improvements in Machines for Pulping Up Paper and Paper Materials.
I, CASIMIR WURSTER, of Abbey Road, St. John's Wood, London, N.W.,
Chemist, 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:-
For pulping up paper and paper substitutes the "Kollergang" (edge runners)
or Stones" (discs) are nearly exclusively in use, although the Stones show
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a great number of disadvantages. In the first place they require a great deal
of motive power, which is in a bad proportion to the work done and secondly
the "Kollergang" grinds up and shortens not only the fibres but with them
also all hard and soft foreign matter contained in the paperstock.
For years experiments have been made with other machines with a view to
supplant the "Stones" but none of the new implements have given entire satis-
faction so far, as most of them shew the same disadvantages as the "Kollergang."
In this respect there might especially be mentioned the combined digester
& agitator and also the disintegrating machine both of which are usually em-
ployed in paper making. Both these machines take no account of the vast
amount of foreign matter and impurities which is always contained in old paper
stock and which interferes with the proper working of the machine and at the
same time is ground up more or less and thus deteriorates the resulting paper
pulp. This is more especially the case in the combined digester & agitator,
where the pieces of rags and strings which make up a large percentage of the
impurities of the old paper, get torn and ground up and spoil the paper pulp.
In the "disintegrator" the fibres of the paper also get shortened and ground up,
which is equivalent to a deterioration of the pulp. The "disintegrator" also
requires a large excess of motive power.
With both these machines the paper stock has to be soaked in water for some
considerable time before it is used and the resulting pulp is too wet for trans-
port. Especially the combined digester & agitator only produces very wet pulp
which contains a multiple of the amount of water wanted for handling the
pulp properly.
The object of the present machine is to combine the advantages of the older
appliances, but to do away with their faults. This object is attained by dividing
the work of the machine into two distinct operations, first a simple kneading of
the paper and afterwards the actual pulping up of the mass.
Referring to the accompanying drawings, Figures 1 and 2 show the present
machine in plan view and cross section respectively. The machine consists of
a trough a the cross section of which has the shape of two circles touching each
other. About one third of the two cylinder casings which form the sides of this
trough is cut away at the upper part so that the trough is open at the top. In
the centres of the two cylinders, shafts b and c are provided, one of which is
driven by a pulley d and drives the other by means of the wheel gearing e f.

page_text: The two shafts are preferably coupled in such a way that they revolve with
different speeds.
To the sides of the trough a two or more lids or covers g h are jointed which
are formed in such a way as to complete the two cylinder walls, and to shut up
the machine when they are closed.
On the whole length of the shafts b and c and at a certain distance from each
other a number of paddles or blades ii are fastened which are made of such
length as to neither touch the walls of the trough nor the blades of the opposite
shaft. These blades are shaped like screw propellers such as are used in steam-
ships and are fastened in such a way on the shafts and c that together they
form approximately an Archimedian screw the axis of which coincides with the
shafts. On the covers gh there are arranged a certain number of stationary
blades or spikes k k which are fastened in such a way that they project into the
open spaces left between the blades i i.
The working of the machine is as follows:-
To start working, the covers are first thrown back and the paper stock is fed
into the machine in the dry state, water being sprinkled into the machine at
the same time, the paper stock may be fed in after having previously been
soaked.
As the opposite blades do not touch each other, in this first operation a knead-
ing only of the stock takes place, and no proper pulping up action is produced
and thus the advantage is gained over the older machines that the stock can be
supplied to the machine in a dry state. As the two shafts revolve with different
speeds the blades i i where they approach each other in the middle of the trough
although going in the same direction have a different velocity. The result will
be that the blades of the one shaft will squeeze off a part of the pulp from the
blades of the other shaft. The helical shape and position of the blades produce
a slow propelling action of the kneaded stock towards the other end of the trough.
In this way the whole stock is continuously thrown about, mixed and kneaded,
but strings and rags are not torn or ground up. The larger and harder foreign
substances do not combine with the kneaded stock but rise to the surface of the
kneaded mass and can be easily picked out by hand. Strings and rags fasten
round the blades and shafts and can also be taken away by hand when the
machine is stopped for this purpose.
By this preliminary kneading, most of the impurities and foreign matter of
the paper stock are got rid of and the real pulping up can then be proceeded
with. For this purpose the covers are now closed, and the kneaded stock not
only continues to be thrown about as before, but is also squeezed through the
interstices between the stationary blades of the covers by each turn of the rotat-
ing blades and thus the disintegrating and pulping up action takes place.
In this second phase the machine works very much like a combined digester
& agitator, but through its horizontal position, allowing of it being worked first
with open covers, the disadvantages of the ordinary digester & agitator, especially
the tearing up of strings and rags, are avoided. For this reason the new pulping
machine is also more economical, since the grinding up of the strings, rags
and other hard substances requires a great deal of power. But the new machine
also produces a much dryer pulp, and will also pulp up very hard, sized papers
which escape being pulped up in the ordinary "disintegrator." My new machine
also avoids another disadvantage of the ordinary "disintegrator" viz.: The shorten-
ing of the fibres themselves. Moreover it combines in this respect the advan-
tage of the digester & agitator with that of the ordinary disintegrator not pos-
sessed by the former of working continually.
If continuous working is preferred, the one end of the trough towards which
the blades propel the pulp is provided with an opening m and the cover h
situated next to this end is kept closed from the beginning of the operation and
the other cover is kept open the whole time.
When working continuously the propeller action of the blades ii comes into

page_text: action. By means of this arrangement the paper stock fed into the machine is
at the same time kneaded and continually transported forward towards the
further end of the trough.
The pitch of the screw and the size of the opening m at the end of the trough
are regulated so as to allow the stock enough time to be thoroughly kneaded
in the first open part of the trough and the foreign matter and impurities to be
picked out before the stock is conveyed into the second or closed part of the
trough, where the stock is subjected to the action of the combined stationary
and rotating blades and is ultimately delivered as pulp through the opening m
in the end in form of a continuous string.
In this way of working the two different operations of kneading and of pulp-
ing up of the stock are locally separated while in the first instance the two
operations were temporarily separated.
By this method of continuous working also all stopping for the purpose of
emptying the machine after each charge is rendered unnecessary.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
--
1. A machine for pulping up paper and paper materials which consists in a
trough open at the top, two substantially parallel and horizontal shafts geared
together, means for driving said shafts, a series of blades fixed on each of said
shafts, and two or more lids or covers removably fastened to the edges of the
said trough and arranged to shut it up when closed, said covers being provided
with a number of stationary blades or spikes arranged to project into the spaces
left between the aforementioned blades fixed on the shafts the whole substan-
tially as and for the purpose described.
2. In the machine described and claimed above, connecting the two shafts by
a gearing which causes them to rotate with different velocities substantially
as described.
3. In the machine described and claimed above, forming the abovementioned
blades ii of a shape substantially resembling the shape of ships propeller blades
and fixing them on the shafts at such distances from each other and in such
positions, that they substantially coincide with a helical surface having an axis
coinciding with the centre lines of said shafts, for the purpose of transporting
the stock automatically from one end of the trough to the other, substantially as
described.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.