AU654610B2 - Components for grading fibrous material - Google Patents

Description

S F Ref: 229546

AUSTRALIA

PATENTS ACT 1990 646 0 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

r r r Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: ASSOCIATED PROVISIONAL [31] Application No(s) PL0437 Ankal Pty Limited Level 7 114-120 Castlereagh Street Sydney New South Wales 2000

AUSTRALIA

Andrew Ferdinand Kaldor Spruson Fer3uson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Components for Grading Fibrous Material APPLICATION DETAILS [33] Country

AU

[32] Application Date 16 January 1992 The following statement is a full description of this invention, including the best method of performing it known to melus:- 5815/5

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-2- COMPONENTS FOR GRADING FIBROUS MATERIAL This invention relates to apparatus for the separation of dry material into distinct phases, and more particularly for the separation of fibrous bark from core material of chopped or crushed stalks of a crop such as Kenaf. This technology is related to the subject matter of Australian Provisional Patent Application No. PK 4363 and Australian Patent 600068 Patent 5,019,248) all of which are incorporated herein by reference.

BACKGROUND ART In the case of the Kenaf plant it is composed of stalks having a fibrous bark and core, of which the former possesses long fibres capable of producing a high quality paper pulp, while the latter is of lesser quality short fibre composition. In some areas of the world the process of recovering the bark fibre comprises cutting and bundling of the 15 stalks, which are dried in the field and then retted with the bark fibre being scutched from the central woody stem. This is a time-consuming task and the bark fibre that is obtained is not in the best form for paper pulping.

Proposals have been made for machine processing of the harvested stalks and this has entailed firstly crushing, grinding or chopping of the stalks, and subsequently separation of the bulk material into separate phases. A modified crushing mill similar to that utilised in the sugar cane industry has been utilised for the first stage of processing. In another instance a forage harvester has been used to gather the crop for baling in a finely chopped condition. However, it has not been possible to achieve efficient, high quality grading with conventional separation apparatus.

OBJECTS AND SUMMARY OF THE IhVENTION It is an object of the invention to provide an Improved separation for grading fibrous material which is efficient and achieves a high degree of separation of the phases of the material.

There is disclosed herein a separation body comprising: inner and outer concentric, perforated, cylindrical chambers rotatable about an inclined axis, an inlet to an upper end of the body, an outlet from the w3w~r end of the body, and an imperforate collar around an upper portion of the inner cylinder adjacent to said inlet.

RLF/0047m -3 BRIEF DESCRIPTION OF THE DRANINGS A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: Fig. 1 is a side elevation, partly in broken section, of a three compartment separation apparatus; Fig. 2 is a diagrammatic representation in perspective of the internal construction of the apparatus; Fig. 3 is a diagrammatic representation in end elevation thereof; Fig. 4 is a perspective .iew of an anti-clogging collar; Fig. 5 is a schematic cross section of a separation body with an imperforate collar located on the inner compartment entry.

Fig. 6 is a schematic diagram of a device comprising multiple single compartment separators; and Fig. 7 is a schematic representation of a vacuum box and vacuums separation area.

ith reference to Figs. 1 to 3 it will be seen that a separation apparatus consists of a hollow, cylindrical, perforated body 10 rotatable upon a series of support wheels 11 of which wheel 11A is supplied with driving power via the shaft 12, gear, or other means in order to effect rotation of the body 10. Additional wheels 11 may also be supplied with driving power. The support wheels 11 are, for example, fixed upon an upper beam 13 carried by a frame 14 in such a way that the beam 13 is downwardly inclined from an input end 15 of the apparatus.

The entire body 10 may be enclosed by a housing 16 provided with a 25 removable cover 17. The main body of the housing 16 is divided into three separate longitudinally arranged sections 16A, 16B and 16C with the floor 18 of each section opening into a respective belt, air or auger conveyor 19 (or other means) which at its cutput end discharges through a chute 20 onto a belt conveyor 21 for gathering and disposal of a solid phase of material resulting from separation, as will be described hereafter. A second belt conveyor 22 collects material of a different phase, in a manner described hereafter, to deposit this phase upon a third conveyor 23 for its disposal.

The perforated body 10 consists of an inner cylinder 24 and includes a cylindrical wall composed of steel mesh, say of a mesh gauge of 5cm X 5cm. As represented in the drawings two or more, preferably three separate compartments 25A, 25B and 25C are provided within the perforated cylinder 24 by spaced annular partitions 26 which may be solid RLF/0047m -4 or alternatply formed of steel mesh of say 5cm X 5cm gauge.

Communication between compartments 25 is effected through the central openings 27 in the partition walls 26. The perforated cylinder 24 is enclosed by an outer cylinder 28 comprising a wall 29 of steel mesh of a gauge of say 2.5cm X 2.5cm. Intermediate gaps 30 are provided In the wall 29 whereby the cylinder 28 is in three longitudinal sections 28A, 28B and 28C. Imperforate, annular plates 31 and 32 enclose the opposite ends of both the perforate cylinders 24 and 28. Bulk material input, under air pressure may be applied via ducting 33 through the central opening 34 in the end plate 31. An equalizer may be used so that the bulk material drops into the opening under the effect of gravity. In the alternative a conveyor may be used to deposit the material into the opening. A discharge duct 36, which is preferably imperforate, although shown otherwise, is secured to the central opening 37 in the discharge 15 end plate 32. It is envisaged that two, or even more, similar outer cylinders, concentric with each other and of different diameters, may be incorporated to enhance separation in some instances.

Within the perforate cylinder 24 are fixed, flat, rectangular baffles 38, comprising steel mesh of say 5cm X 5cm gauge, spaced circumferentially and internally around each of the compartments 25A, and 25C, and extending between partitions 26 and, therefore, the full length of each compartment 25. The disposition of the baffles 38 within any compartment 25 is more clearly represented in Fig. 3, where six baffles 38 are shown secured along one of their sides to the interior of 25 the perforate cylinder 24 with the broad face 39 of each forwardly inclined from a radial alignment with the axis of the body 10, as viewed in respect of the direction of its rotation as indicated by the arrow 40. It will be noted from Fig. 1 that the gaps 30 in the outer perforate wall 29 correspond to gaps 41 in the housing 16, and that these gaps 41 overli, the conveyor 22.

When a bulk of crop, such as Kenaf, which has been pulverised, crushed, or chopped, is to be supplied to the apparatus for separation into separate phases, it will be preferably transported to the site in the form of bales or modules which are then advanced upon a conveyor or other means to rotating shredders or module or bale breakers which discharge a continuous stream of bulk crop into the entry to the rotatable body 10. In one instance the body 10 has been inclined at a downward angle of about 20 degrees and caused to rotate about its axis at RLF/0047m a speed of 24 revolutions per minute. Although, the inclination of degrees is preferred rotation speeds of from 10 to 35 revolutions per minute could be employed. As a result the baffles 38 impart a tumbling action to the bulk material within the first compartment 25A. Due to the forward inclination of the baffles 38 the material is carried to its maximum height before being allowed to fall under gravity during rotation of the cylinders 24 and 28. In one instance the inclination of the baffles 38 is approximately 30-35 degrees, but this is not a strict requirement. In one embodiment, a successful arrangement comprises an outer cylinder diameter of 3.25m, an inner cylinder diameter of 2.25m and a baffle tip diameter of 1.85m.

The bulk material of Kenaf in this compartment 25A is generally composed of three phases, firstly a mixture of relatively fine particles of core material and fibrous bark material, as well as a relatively small 15 quantity of large chunks of core material. The larger particles will readily separate from the bark fibre and pass through the mesh of the inner perforate cylinder 24 from where it will travel down the inside of the outer cylinder 28 to be discharged at the first gap 30 to fall through an opening 41 between the sections of the housing 16 onto the conveyor 22. Further separation occurs in succeeding compartments and 25C for discharge of large core particles mixed with some bark at other positions onto the conveyor 22. As this phase of the bulk material is undesirable for pulping, it may be returned to the bale breaker 44 via the conveyor 23, or to other pulverising machinery, for subsequent 25 re-input to the separation apparatus or further separated into primarily bark and core components.

Due to the elevation via the baffles 38 within the inner cylinder 24 of the bark fibre admixed with fine particles of core material separation of these two phases principally occurs during falling of the admixture under gravity. The small core particles pass through the mesh of both the inner and outer cylinders 24 and 28 and is gathered within the respective sections of the housing 16 for supply to the conveyor 21.

The output from this conveyor 21 is, therefore, pure relatively Fine particles of Kenaf core material suitable for paper pulping.

Due to the inclination of the body 10 the bark fibre is advanced from compartment to compartment by dropping from a baffle 38 through the central opening 27 of any partition 26 until it is discharged from the outlet duct 36 as pure, high quality fibre. The more compartments RLF/0047m -6provided in the body 10 the greater the purity of the recovered fibre, but it has been found that three-stage separation, as shown in Figures 1 and 6, is effective to obtain acceptable quality of phases without over complication of structure. Any suitable conveyor or storage hopper 47 may be utilised for collection of the discharged bark fibre phase.

In some instances choking of the space between the cylinders 24 and 29 may occur, and to prevent this, and also to assist In separation of the two principal phases, fans 8--may be provided in the housing 16 to direct air substantially radially through the cylinder 28.

In the alternative, choking between cylinders can be ameliorated by providing an imperforate collar 101 around an upper portion of the inner cylinder 24 adjacent a partition 26. This feature is shown in Figures 4 and 5. With or without the use of a solid rather than perforated partition 26, the collar 101 minimizes the accumulation of fibres which cause choking between cylinder, 24, 28 at the upper end 102 of a compartment 103. It will be appreciated that the anti-choking collar 101 may be applied to any inner cylinder regardless of whether single or multiple inner cylinders are used or whether the device employs one or more single compartment bodies (for example as shown in Figure 5) or multiple compartment separation bodies (as shown in Figure 2).

previously mentioned, separation can occur in a relatively large S.....single body, multiple compartment devices as shown in Figures 1 and 2 or in arrangements of 1, 2 or more single compartment separator bodies. A modular arrangement of three single compartment separator bodies is shown 25 in Figure 6. In the multiple body example, the separation which occurs in each body is roughly comparable to the separation which occurs in each compartment of the device shown in Figures 1 and 2. Thus, each chamber or single compartment body delivers fine material 110 which passes through both inner and outer cylinders, bark fibres which are discharged from the bottom end of the inner cylinder 111 and reclaimable masses of core which pass through the inner cylinder but not the outer are therefore discharged from the gap 112 between inner and outer cylinders.

As shown in Figure 1, the handling of collectable materials can be done with belt conveyors. However, the separated phases (as well as the initial loading) can be accomplished using air conveying such as vacuum conveying, or using both belt and air conveying. For example, as shown in Figure 6, the reclaimable material 112 from the gap can be fed by belt conveyor (not shown) to a vacuum feeder/separator 115. As shown in conveyor (not shown) to a vacuum feeder/separator ll5. As shown in LF/0047m -7- Figure 7, the feeder/separator collects the reclaim material 112 on for example a belt 116 in a vacuum box 117 and delivers it to a vacuum separation are 118 where an air flow from a vacuum feeder 119 and a hinged flap 120 further separate less desirable fibres 121 upwardly away from other fibres 122. A similar device 123 may optionally be applied to the singular or combined core fibre output 110 for separating fine bark material 125 from the heavier fine core material 110.

A preferred embodiment has been described in the foregoing passages and it should be understood that other forms, modifications and refinements are feasible within the scope of this invention.

S

*m~ RLF/0047m

Claims (1)

1. 8- The claims defining the invention are as follows: 1. A separation body comprising: inner and outer concentric, perforated, cylindrical chambers rotatable about an inclined axis, an inlet to an upper end of the body, an outlet from the lower end of the body, and an imperforate collar around an upper portion of the inner cylinder adjacent to said inlet. 2. The separation body of claim 1 wherein at least one of the inner and/or outer chambers has at least one internal lonigitudinal baffle, the baffle extending radially inwardly from an internal surface thereof. 3. The separator body of claim 1 or claim 2 wherein there is defined a gap space between the inner and outer cylinders, which gap 15 space discharges through an opening located on a lower end wall of the body. 9* 9 f *1 C 9 4. A system comprising a of the preceding claims, wherein inlet of an adjacent body. 5. The system of claim 4 separation body are colinear. 6. The system of claim 4 rotation of each body, a fibrous discharge from the outlet of one another body, while a more solid perforated chambers. series of separation bodies of any one the outlet of one body leads to the wherein respective axes of each or claim phase of body and phase is 5 being adapted such that upon material is conveyed in turn to conveyed into the inlet of discharged through said of claims 1 to 3 or the system as hereinbefore described with 7. The separation body of any one of any one of claims 4 to 6 substantially reference to the accompanying drawings. DATED this THIRTEENTH day of JANUARY 1993 Ankal Pty Limited Patent Attorneys for the Applicant SPRUSON FERGUSON RLF/0047m COMPONENTS FOR GRADING FIBROUS MATERIAL S ABSTRACT OF THE DISCLOSURE A separator for the separation of fibrous bark from core material of chopped or crushed stalks of a crop such as Kenaf comprises two or more hollow bodies (10) for rotation on inclined axes, each having a perforated wall, an upper inlet and lower outlet ends. Provided alongside each inlet is an inlet collar (101). Within at least one of the bodies is provided a plurality of longitudinally extending, circumferentially spaced baffles With rotation of each body while downwardly inclined from the inret to the outlet, a fibrous phase of the material is conveyed in turn to discharge from the outlet end of one body and conveyed into the inlet of another body, while a more solid phase is discharged through the perforated walls of the bodies. a. o •Figs. 3 and 6 o *o S I. S RLF/0047m