CA1243986A - Apparatus for fractionating fiber suspensions - Google Patents

Apparatus for fractionating fiber suspensions

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Publication number
CA1243986A
CA1243986A CA000463583A CA463583A CA1243986A CA 1243986 A CA1243986 A CA 1243986A CA 000463583 A CA000463583 A CA 000463583A CA 463583 A CA463583 A CA 463583A CA 1243986 A CA1243986 A CA 1243986A
Authority
CA
Canada
Prior art keywords
vane
fiber
fractionating
area
shaft
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA000463583A
Other languages
French (fr)
Inventor
N.A. Lennart Wikdahl
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Application granted granted Critical
Publication of CA1243986A publication Critical patent/CA1243986A/en
Expired legal-status Critical Current

Links

Classifications

    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21DTREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
    • D21D5/00Purification of the pulp suspension by mechanical means; Apparatus therefor
    • D21D5/02Straining or screening the pulp
    • D21D5/04Flat screens
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21DTREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
    • D21D5/00Purification of the pulp suspension by mechanical means; Apparatus therefor
    • D21D5/02Straining or screening the pulp

Abstract

APPLICANT: N. A. LENNART WIKDAHL

TITLE: APPARATUS FOR FRACTIONATING FIBER SUSPENSIONS

ABSTRACT OF THE DISCLOSURE

An apparatus for fractionating fiber suspensions in-cludes a chamber converging towards its periphery and formed by two annular fiber fractionating means, preferably imple-mented as truncated cones, a collection trough arranged con-centric to and at the periphery of the chamber for fibers retained by the fiber fractionating means, and agitating means departing from a centrally arranged shaft and rotatable therewith, the means having vanes contiguous to the fiber fractionating means, the vanes having an engagement area coacting with the fiber fractionating means.

Description

L3~6 APPARATUS FOR FR~CTIONATING FIBER SUSPENSIONS
.

The present invention relates to an apparatus for fractionating aqueous fiber suspensions containing cellu-lose fibers, more specifically a fiber fractionating appa-ratus of the kind disclosed in the preamble to Claim 1.
In the present application and claims there is intended a division of an aqueous suspPnsion of cellulose fibers into two fractions, of which the fixst contains fibers slushed up in wat~r, which are substantially above a given size, and the second contains fibers substantially below a given size, the boundary between the fractions not being sharp but depending on the statistical character of the fractionating method.
Examples of such fiber fractionation are rough screening, fine screening and thickening. In rough screening the first fraction mainly contains larger fiber bundles, shives and larger particles, while the second fraction contains fibers of different sizes as well as fines. The reverse condition is obtained in thickening. The first fraction contains, generally speaking, all fibers except a portion of fines, while *he second fractïon only consists of liquid and fines.
The object of the present invention is to provide an apparatus for fiber fractionation in which the incomin~
fiber suspension is divided into two fractions.
Another object is to provide such fractionations as rough screening, fine-screening-and thickening with inter-mediate forms of fractioning of fibers in the same apparatus by merely changing the fractionating`means.
The intended object is achieved with a fiber frac-tion apparatus which includes an annular chamber convergin~
towards its periphery, formed by two annular elements pre-ferably implemented as truncated cones, of which at least one i5 a fiber fractionating means; a collection trough arranged concentric with the chamber and at its periphery for fibers retained by the elements, from a centrally !

~ 1 -3~

arranged rotatable shaft and agitation means rotatable with the shaft, the agitation means having vanes extending in the collec-tion trough and situated adjacent the fiher fraction-atin~ means, each vane having an engagement area engaging against the fiber fractionating means with which it coacts.
The essential features further characterizing the invention are apparent from the claimc:~and in the followiny different embodiments of the invention are described in conjunction with the accompanying drawing, on which Fig. 1 is a section of an embocliment, Fig. 2 is a cross section along the line II-II in Fig. 1, Fig. 3 is an embodiment of the present agitation means, and Figs. 4-7 illustrate contours of vanes used in the present invention.
The fiber fractionation apparatus according to Figs.1 and 2 has two stationary fractionating means 1,2 implemented as annular elements which are axially, laterally arranged relative each other and have the shape of the sweep of a truncated cone. The elements 1,2 are made in one piece and have perforations 23 in the form of xound holes. They are adapted such that they have the concave ~ides facing towards each other and are each removably attached at their outer edges to the inner edge of an annular support element S,6.
~he support elements 5,6 are axially laterally arranged and are connected with its outer edges to a surrounding cylindrical housing or casing 3. Together, the support elements 5,6 and the portion of the cylindrical housing 3 between them form an annular collection trough 4, which is open at the inner edge of the elements 5,6 towards a fiber fractionation chamber 22 which is disposed between the fiber fractionating means 5,6. The fiber fractionating means 1,2 are each removably attached to their respective portions of an inner, intermediate wall consisting of two cylinclrical parts 10,11 concentric with the c~lindrical casing, the parts 10,11 uniting the inner edges of the fiber fractionating means 1,2, each to the respective end wall 14,15 of the casing 3. One cylindrical part 10 of the intermediate wall is on its side facing away from the chamber 22 provided w:ith an inlet 9 for fiber suspension. The o-ther cylindrical part 11 of the intermediat~ wall is provided on its side facing towards the chamber 22 with a wall 12 sealing against the chamber 22. There is a lead-through in the wall 12 for a rotatable shaft 19, which is driven by a motor 18~pro~ecting into the room formed by the cylindrical portion 11 and the ~ l0 joining wall 12.
The rotatable shaft 19 carries two a~itatiny means 20 which are rotatable with the shaft. The agitating means 20 (Fig. 1) are attached to the shaft with the aid of a sleeve 30, which is adjustable axially on the shaft 19 ana non-rotatably connected to it with the aid of a screwed joint atthe free end of the shaft. Two pins 31 project from the sleeve 30, a central body 32 being attached to each pin. The central body is rotatable about and displaceable along the pin 31 for adjusting the position of the agitating means 20.
Two arms 33, directed towards each other, depart from the central body 32, a vane 35 being attached to each arm. Each vane has an orientation relative the fractionating means with which it coacts such that-it engages with an engagement area 33 against the fiber fractionating means, substantially in the direction of the ~eneratrix. The ~imensions of the vane 35 in the direction of the generatrix are such that the vane pro~ects into the collection trough 4, ana during rotation-of the shaft 19-has swept, after ~ne-complete revQlution, over the entire fiber fractionating means with which it coacts.
Further to the collection trough 4, the apparatus has three separated spaces 22,7r8. The first space is the fiber fractionating chamber 22, which is defined by the inlet 9 and the area between the fiber fractionating means 1,2. The chamber 2? is open towards the trough 4 which close to its lowest point has an opening 16 wi-th an outlet 17. The chamber 22 communicates via the openings of the fractionatin~

3~8~i means 1,2 with two connection spaces 7,8. One space 7 is defined b~ the cylindrical casing 3, the end wall 14, the part 10 of the in-termediate wall, the fractionating means 1 and the support elem~nt S which forms the right-hand side wall of the trough 4 in Fig. 1. The second collection space 8 is defined by the cylindrical casing 3, the end wall 15, the wall 12, the part 11 of the intermediate w~ll, the fraction~ting means 2 and the support~element 6. A common outlet 13 is connected to the two collection spaces 7,8 but they may each be provided with an outlet.
The casing 3, as will be seen from Fig. 2, is made in two halves, one upper and one lower half, of which the upper is connected by means of hinges 22 or the like to the lower half and is thus raisable.
In accordance with the invention, the conical angle for the fractionating means 1,2 should lie within the interval 90 - 180 and preferably have a value of between 120 and 150. It is particularly preferred that both of the fractionating means 1,2 have the same conical angle.
According to one embodiment, there is only one fractionating means, the other element being blank, i.e. it lacks perforations.
The fiber fractionating means 1,2 have pexforations 23 in the form of hc>les or slots. The holes are preferably round holes which are cylindrical or conical, the wider part of the conical holes facing -towards a recep$ion space 7 or 8. The slots may also widen towards the reception space, ~r have parallel side walls. The size of the perforations depend on the size of particles it is desired to pass through the fiber fractionating means, and varies within wide limits.
For thickening, at which only a parc of the fines passes through the openings, the perforations have a diameter, or a least diameter if they are conical, of O.2 - 1.5 mm, and with a perforated area, i.e. a quotient between the total area of the perforations and the total area of the frac-tionating means, of at least 50~. The upper limit is about 50~ for practical reasons. When USinCJ 510ts, they have a _ ,q _ 3~

~idth of 0.1 - O.5 mm. The open area is also in this case at least 30%. For screening, the openings have a diameter of 1 - 10 mm, or a width of 0.2 - 2 mm. The open area is between 5~ and 30~.
When using the described apparatus, the fiber suspen-s.ion is supplied through the inlet 9 and is distributed in the inner chamber 22 defined by the fractionating means 1,~.
- The shaft 19 with the agitating means 20 rotates in this chamber, the vanes 35 engaging with their engaging surface 36 against the fractionating means with which they coact, and during their movement prevent fibers and agglomerates, - retained by the fractionating means, from fastening on said means. The heavier fraction of the incoming material, which has not passed through the openings 23 of the fiber frac-tionating means, is fed out to the collection trough 4, where it leaves the apparatus through the opening 16 and outlet 17.
The finer fraction of the incoming material is caused to pass through the openings 23 of the fractionating means 1,2 into the collection spaces 7,8. The latter fraction leaves the collection space 7,8 via the common outlet 13.
Fig. 3 illustrates another embodiment of the agitating means 20 and its attachment to the shaft 19. The arms 33, carrying the vanes 35 via attachment means 34, depart from a central body 29. This body is thrust into a sleeve 28 which is rigidly attached to a sleeve 27. In the same way as the sleeve 30, the sleeve 27 is settable axially and non-rotatably connected to the shaft 19. The central body 29 i~ locked in a desired position with the aid of a nut 26 on the sleeve 28.
The vane 35 consists of a plastic material with a small coefficient of friction, e.g. plastics, and is fixed to the arm 33 via the fixing means 34 in the part closest to the shaft 19. Since the vane is only attached at one end and due to its plasticity, it can bear yieldingly against the fiber fractionating means during the rotation of the agitation means 20. The vane 35 has a dimension in the direction of the generatrix such that it extends into the collection trough 4~
It thereby reduces or eliminates the edge effe~t resulting in 3~

plugging up of the perforations nearest to the trouyh. The cross section of the vane in the direction of the generafrix is preferably constant.
Implementations of the vane 35 in profile, i.e. in cross section at right angle to the direction of the gene-ratrix, are illustrated in Figs. 4 - 7. The arrow P illus-trates the direction of movement of thle vane. The part of the vane 35 engaging against the fiber fractionating means is denoted by 36 and relates to the engagement area. The engage-ment area 36 has small dimension in the direction of movementof the vane in relation to the total dimension of the vane in the same direction, and is farthest forward on the vane. The art of the vane facing towards the fibre suspension may have or more discernable areas. The first area, which is connected to the engagement area, is denoted by 37. The angle between the area 36 and 37 is a riyht angle or preferably acute, e.g.
90 - 40. The area 37 can be flat, convex or concave. The part of the vane facing towards the fiber suspension can have any of the shapes illustrated in Figs. 1 - 4. What is essential is that the vane has a shape such that it is urged against the fiber fractionating means by the suspension it collides with on rotation of the agitating means 20.
Behind the engagement surface 36, seen in the direc-tion of movement of the vane, thexe is an area 38 at a
2~ distance from the fractionating means and facing towards it.
The distance between the area 38 and the iber fractionating means is 5% - 20% of the total dimension of the vane in its direction of rotation. The area between the area 36 and the area 38 has small extension as seen in the direction of rotation of the vane.
The rear side of the vane, between the area 38 and the portion of the vane factinq towards the fiber suspension, has also importance for the ability of the vane to keep the fractionating means clear. This is preferably a flat area 40, and the angle between it and the area 38 is a right angle or obtuse angle, e.g. 90 ~ 135.
The fiber Eractionating apparatus described hereinbe-39~

fore and illustrated in the drawing is of course onlv to beregarded as an emboAiment of the invention. Other embodi-ments within the scope of the main claim are therefore also conceivable. It is thus not necessary that the shaft of the apparatus is horizontal, as illustrated in the drawing. The shaft may also have another orientation in space, It is of course possible to use any conical angle for the fiber fractionating means within the scope of Claim 1, Neither is it necessary that the conical angle of the fractionating means is constant along the entire length of the generatrix.
On the contrary, it is sufficient that the angle between the geometric axis of the fractionating means and an optionally selected tangential plane to the fractionating means is ; within the preferred interval of 45 - 90 and particularly has a value between 60 and 75, which corresponds to a conical angle of 90 - 180 and 120 - 150, respectively.
This thus signifies that the generatrix of the fractionating means may also consist of a completely or partially curved line.
Finally it should be pointed out that the agitating means may have merely one arm, on which the vane engaging against the fiber fractionating means is attached. Turther-more, the arm or arms may be attached directly to the shaft 19 or via a slee~e axially adjustable on the shaft. The arms may also be adapted resiliently, so that the vanes are urged harder against the fractionating means for increasing the revolutionary rate of the shaft 19.

Claims (16)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Apparatus for fractionating fiber suspension comprising a chamber converging towards its periphery, which is formed by two annular elements formed as truncated cones, of which at least the first is a fiber fractionating means, a collection trough concentric with and disposed at the periphery of the chamber for fibers retained by the elements, agitating means departing from a centrally arranged shaft and rotatable there-with, which has vanes adjoining the fiber fractionating means, characterized in that each vane is resiliently arranged relative to the shaft and has a shape such that it is urged against the fiber fractionating means by the suspension it collides with on rotation of the agitating means.
2. Apparatus as claimed in claim 1, wherein each agitating means has at least one vane, each engaging against its fiber fractionating means substantially in the direction of the generatrices of the respective truncated cone and sweeping over the entire fiber fractionating means during a complete revolu-tion, and that its vanes extend into the collection trough.
3. Apparatus as claimed in claim 1, wherein the dimension of an area of engagement in the direction of rotation of the vane is short in relation to the total dimension of the vane in its direction of rotation.
4. Apparatus as claimed in claim 3, wherein the engagement area is farthest forward on the vane in relation to the direction of rotation of the vane.
5. Apparatus as claimed in claim 3, wherein the vane has an area facing towards the fiber fractionating means and situated behind the engagement area in relation to the direction of rotation of the vane, the area being at a distance from the fiber fractionating means, and in that the distance is 5% - 20% of the dimension of the vane in the direction of rotation of the vane.
6. Apparatus as claimed in claim 1, wherein the rear side of the vane forms an angle of 90° - 135° with the fiber fractionating means.
7. Apparatus as claimed in claim 3, wherein the front edge of the vane forms an angle of 90° - 40° with the engagement area.
8. Apparatus as claimed in claim 3, wherein each vane has at least one flat area and/or an area with continuous curvature, which forms an acute angle with the plane of the engagement area and when the vane rotates collides with the suspension, whereby the vane is urged harder and harder towards the franctionating means with which it coacts for increasing revolutionary rate.
9. Apparatus as claimed in claim 1, wherein the vane comprises a plastic material with small coefficient of friction.
10. Apparatus as claimed in claim 1, wherein the fiber franctionating means are provided with holes or slots with an open area of at most 30%.
11. Apparatus as claimed in claim 1, wherein the fiber fractionating means are provided with holes or slots with an open area of 20% - 50%.
12. Apparatus as claimed in claim 5, wherein the flat rear side of the vane forms an angle with the plane of the engagement area of 90° - 150°.
13. Apparatus as claimed in claim 1, wherein each agitating means includes a central body attachable to the shaft and at least one arm arranged on the central body with an attachment means for a vane on each arm.
14. Apparatus as claimed in claim 1, wherein each agitating means has at least one arm attachable directly or indirectly on the shaft with an attachment means for a vane.
15. A device for the fractionating of fiber suspensions, comprising a radially narrowing chamber created by two annular, formed as truncated cones, at least one of which is a fiber fractionating means, an annular collection trough for collecting fibers retained by the fiber fractionating means and arranged at the periphery concentrically with the chamber, and a centrally arranged rotatable shaft provided with agitation means rotatable with the shaft and having vanes arranged near the fiber fractionating means, characterized in that the annular elements are each made in one piece and are removably fastened at their peripheries.
16. A device according to claim 15, further comprising a support element for each annular element, said support elements being axially laterally arranged and are connected with their outer edges to a cylindrical housing.
CA000463583A 1983-09-30 1984-09-19 Apparatus for fractionating fiber suspensions Expired CA1243986A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8305404-9 1983-09-30
SE8305404A SE452177B (en) 1983-09-30 1983-09-30 DEVICE FOR FRACTIONING FIBER SUSPENSIONS

Publications (1)

Publication Number Publication Date
CA1243986A true CA1243986A (en) 1988-11-01

Family

ID=20352725

Family Applications (2)

Application Number Title Priority Date Filing Date
CA000463583A Expired CA1243986A (en) 1983-09-30 1984-09-19 Apparatus for fractionating fiber suspensions
CA000464012A Expired CA1254732A (en) 1983-09-30 1984-09-26 Drilling mud comprising a high surface area magnetite concentrate

Family Applications After (1)

Application Number Title Priority Date Filing Date
CA000464012A Expired CA1254732A (en) 1983-09-30 1984-09-26 Drilling mud comprising a high surface area magnetite concentrate

Country Status (8)

Country Link
EP (1) EP0138792A3 (en)
JP (1) JPS6099088A (en)
BR (1) BR8404859A (en)
CA (2) CA1243986A (en)
ES (1) ES536356A0 (en)
FI (1) FI76605B (en)
PT (1) PT79268B (en)
SE (1) SE452177B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE502688C2 (en) * 1994-04-21 1995-12-11 Kvaerner Pulping Tech Device for thickening and / or washing a suspension
NZ555693A (en) 2004-12-27 2010-10-29 Eisai R&D Man Co Ltd Matrix type sustained-release preparation containing donepezil
JP7075118B2 (en) * 2018-07-09 2022-05-25 株式会社大善 Moisture-containing pulp-based raw material processing machine

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE7901076L (en) * 1978-11-17 1980-05-18 Nils Anders Lennart Wikdahl TAKE REMOVING ADHESIVE SILGING FROM A SILVER PLATE IN A FILTER SUSPENSION SYSTEM AND A DEVICE FOR EXERCISING THE SET

Also Published As

Publication number Publication date
SE8305404D0 (en) 1983-09-30
JPH0561396B2 (en) 1993-09-06
EP0138792A3 (en) 1986-07-30
EP0138792A2 (en) 1985-04-24
SE8305404L (en) 1985-03-31
JPS6099088A (en) 1985-06-01
BR8404859A (en) 1985-08-13
ES8506837A1 (en) 1985-07-16
FI843807A0 (en) 1984-09-27
ES536356A0 (en) 1985-07-16
FI843807L (en) 1985-03-31
PT79268B (en) 1986-11-12
FI76605B (en) 1988-07-29
PT79268A (en) 1984-10-01
CA1254732A (en) 1989-05-30
SE452177B (en) 1987-11-16

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