US1553976A - Method of manufacturing paper pulp - Google Patents

Description

Sept. .15, 1925,

V. BERNOT ET AL METHOD OF MANUFACTURING PAPER PULP Filed Jan. 27, 1.921

Patented Sept. l5, 1925.

UNITED STATES 1,553,976l PATENT OFFICE.

VIQTO'R BERNOT AND PIERRE RAYMOND FOURNIER, 0F BOULOGNE-SUR-SEINE, FRANCE, ASSIGNORS T0 SOCIT LA PAILLE INDUSTRIELLE, 0F NOYON, FRANCE.

METHOD 0F MANUFACTURING PAPER PULP.

Application mea January 27, 1921. serial No. 440,476.

To all whom t may concern: p

Be it known that We, VICTOR BERNOT, a citizen of they Repub-lic of France, and residing at Boulogne-sur-Seine. 14 bis Rue de Sevres, in t-he Republic of France, and PIERRE RAYMOND FOURNIER, a citizen of the Republic of France, and residing at Boulogne-sur-Seine, 14 bis Rue de Sevres, have invented certain new and useful Improvemen-ts in Methods of Manufacturing Paper Pulp, of which the following is a specification.

This invention relates -to a method and apparatus for the manufacture of paper pulp. The current method of manufacture of paper pulp comprises a series of successive operations such as sorting the raw material in the shape of natural or artificial vegetable fabrics, Washing or dust removal, cutting up, lye treatment, washing after the same, separation of fibres, bleaching; and subsequent Washing. The most important of these operations are the lye treatment and the separation of fibre. The first of these operations serves to dissolve as much as possible the foreign bodies which surround and connect the fibres of pure cellulose, and is usually carried out in a digester at a pressure of about 3 kilogrammes per square centimeter, the Operation lasting from' 2 to 8 hours, or often more. After Washing for 1 to 4hours in a Washing apparatus, the lye-treated rlaterial is submitted to a fibre separating process, for the purpose of separating the fibres Which are still collected in larger or smaller masses. This mechanical operation is generally carried out in a drum containing fixed and moving blades. The paper pulp which is thus Obtained is only in the partially finished condition, inasmuch as it is not homogeneous and requires to be refined in order toi be used for'the manufacture of high grade paers. p The process of manufacture as thus carried' out requires successive treatments of the material, and cannot be considered as a continuous process. It requires a considerable amount of la'boi' and complicated and cumbersome apparatus, while the successive chemical and mechanical Operations are of long duration, the yield being only moderate owing to the factthat the long duration of the chemical operations has a tendency to cause the partial hydrolysis of the fibres. Moreover, the mechanical treatment of the non-homogeneous substances has an unduly energetic and prejudicial action i upon the fibres which are already separated but as an insufficient effect upon the aggregates of fibres which have not been sufficiently separated by the .lye treatment.

In our invention these inconveniences are obviated. vAccording to this invention, a continuous process is employed whereby the material is continuously introduced, lyetreated, ^and has the fibres thereof separated in a continuous current of lye bath. The

separate fibres which are carried along by this current are filtered out and removed Important advantages will result there-` from which Will be hereinafter set forth.

The accompanying drawings which are given by Way of example show a diagrammatic view of a series of apparatus Wherein the present process is applied.

Figure 1 is a diagrammatic view of the Whole series of apparatus.

Figure 2 is a longitudinal section of a lye-treating apparatus and alfibre-s'eparating apparatus suitably combined.

Figure 3 is an elevational View of one of the perforated plates.

The lye-treating apparatus comprises a horizontal cylinder 1 Whereon is disposed a feed hopper 2 employed for the continuous feeding of the ve etable matter to be treated 4by the lye-bat The said cylinder contains ashaft 3 having formed or secured thereon a screw conveyor 4 for propolling the material under treatment from the` end adjacent the feeding hopper to theopposite end of the device. A portion of the said screw-member is preferably adapted to cooperate with the internal edge.

of the feeding aperture which' acts as a cutting blade in order to cut up the raw material into large fragments upon the introduction of the same into the cylinder.

Within a' recess 5 provided in the wall of the cylinder is disposed a member 6 in the form of a wheel which is loosely rotatable upon the shaft thereof 7 and engages the threads o-f the screw member 4. The said wheel serves to prevent the free movement of the material about the said screw, member which might take place in spite of the fluid nature thereof, and the material is now obliged to move forward as the screw rotates. The said cylinder which is chiefiy -used for the lye treatment, is heated, if

" duration for the movement of the material whereby the latter shall be sufficiently penetrated by the` lye ybathl upon attaining the end of the cylinder 1.

For all the material under operation, wood excepted, the duration of the lye treatment does not usually exceed 30 minutes. The matter which arrives at the end 9 of the cylinder still retains substantially the same shape as it had at the feeding end, and the separation of the material is carried out chiefiy in the fibre-separatingapparatus. It may however be advantageous to dispose adjacent the perforated end- 9 of the cylinder 1 a rotary knife 10 for a rough cutting up of the fibrous matter, the said knife cooperating with the bottom part 9 somewhat after the manner of the knife member and perforated type of meat cutter.

The fibre-separating apparatus comprises a cylinder 11 preferably disposed in alignment with the lye-treating cylinder and having therein a series of stationary partitions 12a, 12b, 12 etc. forming various chambers, 10 for instance, such as 13, 13b', .13 etc. the said partitions being provided with the apertures 14a, 14b etc.l of decreasing width, the apertures 14a having for instance several centimeters width whereas lthe apertures 14k are reduced to very narrowslits for the purpose of allowing only the individual fibres to pass through, Within the said chambers are disposed the rotary stirring members 15, 15" 15k which are secured to the shaft 16 disposed according to the axis of the cylinder 11. The said shaft is situated preferably within the shaft 3, this latter being made hollow to this effect, and it also carries the rotary knife 10. A

.small space, for instance 2' millimeters, is

preferably provided between the partitions plate of the current 12 and the stirring members 15vto prevent the shearing of the libres and tocause the latter to be separated from each other by the effect of easy friction within the body of the lye bath and without rough handling.

The shafts 3 and 16 are actuated for instance by belting disposed u on the pulleys 17 and 18 or by gearing or t e like, 1n such manner as to effect the rotation of the stirring members 15 at a much higher speed than that of the screw 4, whereby the forward movement of the lye bath and the material shall be much slower than that of out through the slits of the partition 12k.

It is obvious that the fibres which are more readily separated will pass off more quickly than the fibres which adhere closely together, and each. class of fibres is caused to remain in the separating apparatus only for the time which is strictly necessary to produce'the separating action.

Upon leaving the fibre-separating cylinder, the paste drops into one or more filter presses 19 of any suitable construction whereby the cellulose fibres are retained and separated from the lyebath. It should be remarked that in the present apparatus the lye is not submitted to a high pressure as in the usual digesters.' The lye bath `which is discharged from the filter press'or presses kis conducted through the piping 20 to a pump 21 or other elevating device which returns the same to the hopper 21 The fibres remaining in the filtering devices are discharged therefrom at more or less frequent intervals or by a continuous process, according to the character of the apparatus employed, and the libres are then ready for the washing process. After a sufficient washing, they constitute a pulp which is suitable for paper manufacture.

The present method affords various advantages as compared with known methods, which may be set forth as follows:

A single chemical and mechanical operation is substituted for the two different operations of lye treatment and fibre separation.

The production of' clean and separated fibres, representing paper paste, is now carried out in a continuous manner, this affording'a very considerable advantage as concerns cost of operation.

The apparatus takesup but a small space and requires a minimum of hand labor.

The lye bath is used in a systematic and complete manner, resulting in a minimum w cost of lye substances.

in suspension in the liquid is edgected Without rough handling and without useless deterioration of the fibres.

The herein described combined chemical and mechanical action is so elective that the same apparatus may be used for the treatment of the greater part of natural or artiicial vegetable substances with equal facility, and textile products containingoily substances, such as greasy Waste, can be directly transformed into paper paste Without any previous Washing.

The quantity of material under treatment at any given moment is relatively small, whencev it follows that a large or small amount of substance may be treated with equal facility and with the same relative economy, and a great variety of substances can be treated successively without requiring any stoppage or cleaning of the apparatus, whereby paper paste of various qualities may be produced in a continuous manner.

`Inasnfi'iuch as the fibre separation is obtained with the minimum amount of lye bath, the fibres will not show a tendency to agglomerate into small masses, and moreover, in case a hot treatment is to be carried out, the loss of heat-Will be a minimum by reason of the fact that only a small quantity 'sof material is placed under treatment.

Claim:

A process for the manufacture of paper paste in an endless current of suitable liquid, wherein the raw brous substances are introduced in a continuo/us manner at a given point of the said current and are caused to pass through the libre-removing elements ater having vbeen saturated With the said liquid, the bres being removed from the current a second point in the stream of liquid in the form of a pulp Which is ready for use, `whereby the liquid does not pass again through the same points before all the fibres are removed.

In testimony that We claim the foregoing as our invention, we have signed our names.

VIC'IR BERNOT. PIERRE RAYMOND FOURNIER.

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