WO1997028541A1

WO1997028541A1 - Reclaiming casing from elongate members

Info

Publication number: WO1997028541A1
Application number: PCT/AU1997/000057
Authority: WO
Inventors: George Veres
Original assignee: WATER JET TECHNOLOGIES PTY Ltd
Current assignee: WATER JET TECHNOLOGIES PTY Ltd
Priority date: 1996-02-02
Filing date: 1997-02-03
Publication date: 1997-08-07
Anticipated expiration: 1998-08-02
Also published as: AUPN787496A0

Abstract

A method of recovering the elastomeric casing from core material (55) of a multilayer elongate member (49) comprising feeding the member (49) through an array of high pressure liquid jets (57) directed at the external surface of the member (49), and effecting relative movement between the jets (57) and the member (49) so that the complete periphery of the member (49) is subjected to the high pressure jets (57) to thereby remove the casing in a particulate from the core material (55) of the member (49).

Description

RECLAIMING CASING FROM ELONGATE MEMBERS.

This invention relates to a method and apparatus for reclaiming the elastomeric material such as polymers or rubber from the casing of cables and like elongated members. The reclaiming of casing also enables reclaiming of the metal conductive core material.

It is customary for cables, such as electrical cables to have a casing of an elastomeric material such as natural or synthetic rubber or like polymeric materials, that casing material, in addition to the conductor material, is of significant commercial value, if separated from the electrical conductors and other components about which or in which the casing is located, such recovered materials has a significant commercial value.

Electrical cables are frequently available at the point of manufacture, where faults in the manufacturing process have occurred, and substantial quantity of such cable are rejected and cannot be released for sale. Also, in the demolition of buildings, there are substantial quantities of cable having a rubber or elastomeric material casing which could be reclaimed. If these materials can be effectively separated and reduced to a form suitable for re-use either in cables or for some other purpose there is a substantial commercial value therein and waste of a valuable resource is avoided. It is therefore the object of the present invention to provide a method and apparatus for removing the casing from elongate members, such as electrical cables, in a manner so that the removed casing material, and preferably also the conductive core material, can be recycled, and so that the removal process is economically viable having regard to the potential commercial value of the reclaimed material.

With this object in view, there is provided a method of recovering the elastomeric casing from core material of a multi-layer elongate member comprising feeding the member through an array of high pressure liquid jets directed at the external surface of the member, and effecting relative movement between the jets and the member so that the complete periphery of the member is subjected to the action of the high pressure jets to thereby remove the casing in a particulate form from the core material of the member. Conveniently, the array of jets and/or the elongate member are subjected to a controlled relative movement either individually or in unison as the jets are operating so that the complete periphery of the member is subjected to treatment by the jets. Also, to improve the effectiveness of the respective jets, they may rotate or oscillate about an axis normal to the direction of the elongate member passing therebetween.

The size of the particles of the casing material produced by the above method can be varied by varying both or either one of the rate of feed of the elongate member past the jets and/or the degree of movement of the jets relative to the elongate member such as about the axis of the elongate member and/or about the axis normal to the elongate member.

There is also provided by the present invention, an apparatus for recovering the elastomeric casing from an elongate member comprising means to feed said member along a predetermined path, and an array of high pressure jets connectable to a high pressure liquid source and located relative to said path of the elongate member to impinge jets of said liquid onto the external surface of the elongate member about the periphery thereof to thereby separate the casing material in a particle form from the core of said elongate member.

Conveniently, the array of jets are arranged in a generally circular formation with the axis thereof corresponding to the longitudinal axis of the elongate member being processed.

Preferably the array of jets are supported to rotate about the axis of the elongate member either in a complete circular motion or in an oscillatory arcuate motion about the axis. In one embodiment, each or some of the high pressured jets are arranged and supported to oscillate in a part rotary motion about the axis thereof, preferably in a plane at right angles to the axis of the elongate member.

In another specific embodiment, the array of jets are all mounted on a common support structure which rotates about the axis of the elongate member or alternatively, may oscillate back and forth about the axis in an arcuate motion, preferably within a range of 30° to 120° of oscillation. The invention will be more readily understood from the following description of two respective forms of the apparatus and of the method used in the separation of the casing material from the core of an elongate member such as a cable encased in a covering of elastomeric material. In the drawings:

Figure 1 is a diagram of the structure of a single core high voltage electrical conductor.

Figure 2 is a diagram of the structure of a three phase electrical conductor. Figure 3 is a diagrammatic representation of the method for removing the insulating casing from the elongate metal member by the use of high pressure liquid jets;

Figure 4 is a side view of one embodiment of an apparatus for removing the polymeric insulating material from an electrical cable. Figure 5 is a sectional view along line A - A in Figure 4.

Figure 6 is a sectional view along the line B - B in Figure 5.

Figure 7 is a diagrammatic illustration of an alternative apparatus for processing relatively short lengths of electrical cable.

Referring now to the drawings and in particular to Figure 1 , there is illustrated therein the construction of a single core high tension electrical cable having a central aluminium conductor 10 made up of a plurality of individual conductors helically wound together. The conductor 10 is located centrally in a cylindrical casing 11 of polyethylene mounded in situ about the conductor 10.

The casing 11 is enclosed in a multi layer shielding which may be of varying number of layers of varying constructions. In the cable illustrated there are five outer layers commencing with a spirally wound copper wire shield 12 about the outer face of the polyethylene 11 and a helically wound copper strip 13 wound about the copper wire shield. A helically wound paper layer 14 is provided around the copper strip 13 with a cylindrically wound aluminium strip thereabout forming a further shield with an outer wear resistant polymer coating 16 forming the outer wall of the cable. Subject to the use to which the cable is to be applied and the environment in which it will operate, the number and arrangement of the various coverings 12 to 16 will vary with the limit normally being the outer layer of polymer 16 being directly applied to the exterior of the polyethylene casing. The removal of the outer polymer layer 16 may be performed by the use of high pressure liquid jets. However the remaining protective layers 12 to 15 are removed in individual unwinding operations or may be removed in a longitudinal splitting operation where a suitable cutter cuts through the various layers down to but not including the polyethylene layer and are then peeled away from the central polyethylene layer 11.

Single cables having three conductors incorporated therein are widely used and commonly referred to as three phase cables. An example of the construction of such a cable is illustrated in Figure 2 of the drawings.

Each of the three aluminium conductors 20 are enclosed in their individual polyethylene casing 21 , and the three conductors are each individually housed in spirally wound paper casing 23 which in turn are enclosed in respective pairs of aluminium strip 24 spirally wound in respective opposite directions about the respective individual conductors. The three conductors 20 are then in turn encased in to steel strip casings made up of respective spirally wound metal strips 25, the spirals being wound in opposite directions. The three assembled conductors held together by the respective steel strips, are then enclosed in an outer protective polymer layer 27.

Between the three conductors when assembled in a side by side longitudinal relationship, normally have provided between each two conductors a filler hose 28 so as to provide an appropriate support for the materials wound about the three assembled cores 23 so as to give a generally smooth continuous external surface to the outer polymer casing of the cable.

Referring now to Figure 3 of the drawings, the elongate member or cable 30 is typically a single conductor electrical cable such as previously described with reference to Figure 1 , having a multi strand wire core 31 and a casing 32 of elastomeric material having the desired insulation characteristics such as rubber or one of the well known elastomers such as polyethylene. As shown in Figure 3 the cable has had all the outer protection as previously described with reference to Figure 1 removed leaving only the conductor core 31 and main insulator casing 32.

The cable 30 is supported and fed forward at a controlled rate by the rollers 33, and if required, additional other rollers or formations of rollers may be used. The array of high pressure jets units 36 consisting of four individual jet units 36 are arranged in a circular formation about the cable 30 in a right angle cross formation. Each jet unit 36 has a nozzle portion 37 which houses one or preferably a plurality of nozzles (not shown), through which high pressure liquid, such as water, can be selectively delivered. Each of the jet units 36 are coupled to a source of high pressure liquid, such as water, and conveniently may be supplied from a single high pressure pump (not shown) operating at a pressure up to the order of 2 to 2.5 Bar, subject to the nature and thickness and physical nature of the insulation casing 32 to be removed. Preferably, the four or multiple number of jet units are mounted in a unitary carrier (not shown) which in turn may be supported to rotate about an axis coincident with the axis of the cable 30. Alternatively, the assembly may be arranged to oscillate in a part rotary motion about that axis, through an angle which may range between 30 and 120°, more conveniently between 35 and 110°.

In addition, each of the jet units 36 may be supported in the carrier for rotation about the axis of the jet unit. This motion may be generated by a suitable angling of the jets with respect to the axis of rotation of the jet unit, so that no external drive system is required. Preferably each of the jet units 36 has a plurality of nozzles each issuing an individual stream of high pressure liquid to impinge upon the casing of the cable and to breakdown the casing into a particulate form.

In practice, the assembly of jets are arranged within an appropriate housing so that the casing material, in the particle form generated by the action of the high pressure jets, is collected with the liquid issued from the jets. This is subsequently processed to separate the particles from the liquid, and then further processing the particles, as may be appropriate, such as by further grinding, to reduce the particle size to suit the proposed subsequent use of the recovered material.

Referring now to Figures 4, 5 and 6 there is depicted therein one form of the equipment which may be used to carry our the present invention in the processing of electrical cable which is available in substantial lengths, such as in coils of a size as the cable is produced by the manufacturer.

The process chamber 50 is of a generally cylindrical form supported on a steel structure 51 having an arrangement of support legs 52 so that the chamber 50 is orientated with the axis thereof substantially horizontal. As can be seen more readily in Figure 6, the cable 49 to be processed enters the chamber 50 from one end thereof, and the central metal conductor component 55 of the cable is discharged from the opposite end of the chamber on the central axis thereof, such as through the aperture 53. The high pressure liquid and the removed insulator casing material is discharged from the bottom of the chamber 50 via the duct 54, and is passed to a suitable separator whereby the recovered insulating material is separated from the water so that the latter may be further cleaned and then recycled.

As can be seen in Figures 5 and 6 there is provided in the chamber 50 two axially spaced banks of high pressured jet nozzles 57 and 58, each bank consisting of four co-planer nozzles 59 arranged in equally spaced peripheral relationship as shown in Figure 6. The respective banks of nozzles are connectable to a suitable source of high pressure liquid (not shown), such as water, preferably at a pressure of 2 to 2.5 Bar. The nozzles 59 in each of the two banks 57, 58 are arranged in respective common radial planes, however it can be desirous in some situations to arrange the respective banks 59 in radial arrays that are 45° out of phase.

Provision is made in the mounting blocks 59 so that the spacing of the nozzles 59 from the nominal external surface of the electrical cable 49 to be processed may be adjusted so that the radial spacing of the nozzle to the point of impact of the liquid jet with the cable being processed is such that the complete periphery of the cable is affectively exposed to the impact of the high pressure liquid issuing from the jets. Hence in a single pass through the chamber 50 the total peripheral extent of the cable is reduced to the required particle size leaving only the central metal conductor 55.

As the liquid jet issuing from the respective nozzle is of a generally conical form with the diameter thereof increasing with the increase in length of the jet from the nozzle, the adjustment of the spacing of the end of the nozzle from the surface of the cable being passed through the chamber is adjusted to suit cables of different nominal diameters. In this regard it will also be appreciated that the distance between the surface of the cable to be processed and the nozzle also influences the effectiveness of the cutting action of the jet stream. Thus the nozzles are individually mounted in the chamber so that nozzles having different jet configurations and performance may be installed to suit the particular size and type of cable being processed.

There is shown in Figure 7 a diagrammatic representation of a further method and apparatus for the removing of the casing from an elongate member which is particularly suitable for use in the processing of members which may be of a relatively short length in comparison with continuous elongate members of a length running into tens or hundreds of metres in length.

The apparatus includes three endless conveyors comprising a feed conveyor A having spaced pulleys 62, 63 and 64 and belt 60 which cooperates with the portion 61 of the primary conveyor B consisting of the pulleys 68, 69, 70 and 71 and the secondary conveyor C comprising the pulleys 72, 73, 74, 75, 76, 77 and 78. It will be noted that in this construction, the pulleys 68, 69 and 70 are double pulleys and cooperate respectively with the conveyor belts 61 and 66 respectively. The material to be processed is fed in between the feed conveyor A and the primary conveyor B as indicated at the arrow X. Having regard to the configuration of the feed conveyor A and the guide plate 80, various lengths of elongate members and various sizes may be fed into the processing mechanism, unless they are of such a size as to be not capable of passage by the conveyors.

The material fed by the conveyors A and B pass beneath the ultra high pressure jet unit 81 which may be a single or multiple number of jets so that the casing component of the material is separated in a particulate form the remainder of the article and the separated casing material is collected in the hopper 86 from which it can be extracted by the conveyor such as an auger conveyor 87. After the casing material has been removed from one side of the elongate member being processed, the member after leaving the UHP jet 81 , is received between the sections 83 and 84 of the belts of conveyor B and C in the area where the belts pass around the pulleys 68 and 69 respectively. The member is then carried whilst held between these conveyor belts up to the pair of UHP jets 88 and 89 where they are passed therebeneath so that the side of the elongate member opposite to that exposed to the UHP jet 81 is now exposed to the pair of UHP jets 88 and 89 on the opposite side. The material separated from the core of the elongate member by the UHP jets 88 and 89 is collected in the hopper 90 and can be conveyed therefrom such as by the screw conveyor indicated at 91. The conveyor belt 60 then passes around the pulleys 75, 74, 73 and 72 to be represented at the exit from the single UHP jet 81.

This process and apparatus is particularly suitable for processing relatively short lengths of elongate material having a rubber or plastic casing thereabout, such as electrical cables, but is particularly appropriate for processing relatively short lengths of such cables which may be successively fed into the machine, not being in a unitary continuous form. Also, because the material is fed via a conveyor with appropriate belts, it will accept material of differing sizes within reasonable limits of variation.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A method of recovering the elastomeric casing from core material of a multi-layer elongate member comprising feeding the member through an array of high pressure liquid jets directed at the external surface of the member, and effecting relative movement between the jets and the member so that the complete periphery of the member is subjected to the action of the high pressure jets to thereby remove the casing in a particulate form from the core material of the member.

2. A method as claimed in claim 1 , wherein the jets are arranged in an array about the periphery of the member, and the member is passed centrally through the array.

3. A method as claimed in claim 2, wherein at least two arrays of jets, each array comprising a plurality of jets arranged in an annular formation about the elongate member.

4. A method as claimed in any one of claims 1 to 3, wherein the liquid is supplied to the jets at a pressure up to the order of 2 to 2.5 Bar.

5. A method as claimed in any one of claims 1 to 4, wherein the elongate member is an insulated electrical cable having a metal conductive core encased in a polymeric material.

6. A method as claimed in claim 5, wherein the polymeric material is polyethylene.

7. An apparatus for recovering the elastomeric casing from an elongate member comprising means to feed said member along a predetermined path, and an array of high pressure jets connectable to a high pressure liquid source and located relative to said path of the elongate member to impinge jets of said liquid onto the external surface of the elongate member about the periphery thereof to thereby separate the casing material in a particle form from the core of said elongate member.

8. An apparatus as claimed in claim 7, wherein the jets are arranged to in use form at least part of an arcuate array about the path of the elongate member.

9. An apparatus as claimed in claim 8, wherein the jets are arranged to form two circular arrays about the path of the elongate member, said arrays being spaced in the direction of movement of the elongate member.

10. An apparatus as claimed in claim 9, wherein the position of the respective jets relative to the axis of the circular array is adjustable.

11. An apparatus as claimed in any one of claims 9 or 10, wherein the arrays of jets are located in a chamber adapted to permit the elongate member to pass therethrough, and wherein the liquid issuing from the jets and the particulate casing material is collected.