GB2142351A - Extraction apparatus and method - Google Patents

Abstract

Apparatus for extracting reinforcing yarns or fibres from a solid material such as waste reinforced plastics hose, comprises rotating blades (4) to comminute the solid material to release the yarn or fibre and a fan (9) to create an air stream to carry the released yarn or fibre away from the blades to a collector such as a filter (12). A secondary collector, such as a settlement tank (14), may be used downstream of the filter to improve separation efficiency, and additional fibre may be extracted, for example by a cyclone separator (19), from the comminuted solid material which falls from the blades. <IMAGE>

Description

SPECIFICATION Extraction apparatus and method The present invention relates to an apparatus and method for extracting reinforcing yarn or fibre from solid materials reinforced thereby such as, for example, yarn reinforced tubing.

According to the present invention in one aspect there is provided an apparatus for extracting yarn or fibre from a solid material containing such yarn or fibre as reinforcement which includes comminuting means for releasing said yarn or fibre from said solid material and means for creating a gas stream for carrying the released yarn or fibre away from the comminuting means to a collection means.

Conveniently, the comminuting means is present within a chamber having a gas inlet and a gas outlet for passage of the gas stream, and preferably the collection means is a filter positioned upstream of the comminuting means. In embodiments of the present invention having a filter as collection means, it is preferred for such filters to be capable of alternating their position in such manner that, immediately after moving, the wad or yarn or fibre collected thereby can be dropped into a collection unit. It has been found that a compacted wad, which almost fills the filter used, falls away easily therefrom. Advantageously, the means for creating a gas stream is a fan, and preferably in embodiments where the comminuting means is situated within a chamber having a gas inlet and outlet, the fan is situated upstream of the collection means.

The comminuting means themselves are preferably rotating blades, and for the purposes of the present invention it has been found to be particularly convenient to use a commercially available granulator which has a gas inlet and a gas outlet which has been modified by the incorporation therein of a collection means such as a filter and also a fan. Such a granulator may also include a gas balance valve which enables the gas volume and velocity to be adjusted to provide the desired separation.

It will be understood that in some circumstances some yarn or fibre will pass through the collection means of the apparatus of the present invention, and additionally yarn or fibre will not be collected at all for a short period in embodiments thereof having an alternating filter during that time when a collected wad is being dumped into a collection unit. Consequently, it is advantageous in order to increase the yield of recovery of yarn or fibre for the apparatus of the present invention to further include a second yarn or fibre collection means situated upstream of the aforementioned, or first, collection means.

Most preferably this second collection means is additionally upstream of the means for creating a gas stream. Generally, the second collection means takes the form of a hollow container which is in gas flow connection with the gas stream, the container having a gas bag situated thereover or thereon to allow for the escape of excess gas pressure. Any yarn or fibre carried into this second collection means will settle therein and is collected at convenient intervals. In embodiments of the apparatus of the present invention where a chamber of the aforementioned type is used to house the comminuting means, it is preferred for the second yarn collection means to be connected to the gas outlet thereof by a gas flow pipe.

In the apparatus of the present invention, the yarn or fibre which is separated from the solid material by the comminuting means is carried away therefrom by a gas stream, while the solid material is not so carried. Generally, particularly for continuous operation, the apparatus of the present invention is adapted to allow removal of the comminuted solid material from the actual comminuting zone.

Most preferably, the apparatus is so arranged that such comminuted solid material falls away from the comminuting zone by the simple action of gravity. In cases where a chamber is used having a gas inlet and a gas outlet it is convenient for the apparatus to be so arranged that the comminuted solid material falls out of said chamber via the gas inlet.

Comminuted solid material issuing from the apparatus of the present invention may be simply collected at that stage, although it has been found that in a majority of applications, a small amount of yarn or fibre, and also dust, is associated with the comminuted material at that stage. Accordingly, in order to improve recovery yield, it is preferred for the apparatus of the present invention to include secondary means for separating yarn or fibre from the comminuted material. Most preferably, this secondary means is constituted by a cyclone separator. Preferably the cyclone separator has a hopper at its bottom end for discharge of comminuted solid material and a yarn or fibre collector in communication with the top thereof in order to collect the thus separated yarn.Most preferably, embodiments of the present invention having such a cyclone separator include transfer means for transferring comminuted material issuing from the commi nuting to the cyclone separator. Conveniently this takes the form of a transfer tray into which the comminuted solid material falls, the transfer tray being in gas flow communication with the cyclone separator by the provision of a communicating gas flow pipe therebetween.

Provided within the gas flow pipe is a means for creating a gas stream therealong, such as a fan, which is preferably positioned upstream of the transfer tray and downstream of the cyclone separator. The gas flow created by this means should be suffficient to carry the comminuted particles to the cyclone separator together with associated yarn or fibre. In such an arrangement, the yarn or fibre collector which is in communication with the top of the cyclone separator should be such that excess gas pressure may be removed therefrom.

It will be appreciated that in most circumstances, the gas referred to above will conveniently be air.

The present invention will be further illustrated with reference to the sole accompanying drawing which shows a schematic crosssectional view of a preferred apparatus of the present invention.

Referring to the drawing, in which the arrows show the direction of the passage of gas, a granulator generally designated 1 has a chamber 2. Situated within the chamber 2 are comminuting means 3, which in this case are constituted by a pair of rotating blades 4. In communication with the chamber 2 and the outside of the granulator 1 is a material feed passage 5 through which material to be comminuted, for example yarn reinforced PVC tubing 6, can be fed to the comminuting means 3. The chamber 2 of the granulator 1 has a gas outlet 7, a gas inlet 8 and a fan 9 adjacent the outlet 7. In the arrangement shown, the fan 9 is upstream of the comminuting means 3. The granulator 1 also has a water gauge 10 to enable measurements of the gas flow created by the fan 9, and a gas balance valve 11 to allow the gas velocity and volume within the chamber 2 to be adjusted.

Associated with the granulator 1, and positionable intermediate the fan 9 and the comminuting means 3 is a slidable tray and filter assembly 1 2. The tray and filter assembly is slidable between a first position (solid lines) and a second position (chain lines). In its second position, the tray and filter 12 extends across the whole width of the chamber 2. A flow pipe 1 3 connects the outlet 7 of the chamber 2 to a yarn collector 14 which has a gas bag 1 5 thereover. The gas bag 1 5 is such that gas can escape therefrom in order to avoid a build up of gas pressure therewithin.

Positioned to one side of the granulator 1 is a yarn collection unit 1 6 which, in fact, is positioned such that it is directly underneath the tray and filter 1 2 when the latter is in its first position. A transfer tray 1 7 is positioned under the gas inlet 8 of the chamber 2, and a gas flow pipe 18 connects the tray 1 7 to a cyclone separator 1 9. Along the length of the pipe 18 is a fan 20 which is upstream of the tray 1 7 and downstream from the cyclone separator 1 9. The cyclone separator 1 9 has a hopper 21 which itself has a bag filling valve 22 underneath which is positioned a bag filling arrangement 23.A gas flow pipe 24 connects the top of the cyclone separator 19 to a further yarn collector 25 which is gas permeable to allow escape of gas therefrom whereby pressure build up is avoided.

To operate the apparatus of the present invention, the tray and filter assembly 1 2 is positioned as shown in the drawings by chain lines, and the comminuting means 3, the fan 9 and the fan 20 are turned on. The material to be comminuted 6 is then fed via the feed means 5 into the chamber 2 in the vicinity of the comminuting means 3. The comminuting means 3 thereby comminutes the material 6 which is fed in, thus creating comminuted solid particles and yarn pieces which have been released from the surrounding solid. The yarn pieces are carried in by the gas stream created by the fan 9 toward the direction of that fan, while the solid particles and any other yarn which may and still be associated therewith fall under the influence of gravity from the comminuting means 3 into the tray 1 7 via the gas inlet 8 of the chamber 2.The separated yarn within the chamber 2 is carried by the gas stream into contact with the tray and filter assembly 1 2 which collects the vast majority of the separated yarn carried by the gas stream. After a time, the filter 1 2 collects a wad of yarn. When such a wad is collected, the tray and filter assembly 1 2 is moved by sliding to its first position as shown by solid lines in the drawing whereby the wad 26 is released therefrom whereupon it falls into the yarn collection unit 16. It has been found that a compacted wad almost filling the filter 1 2 releases itself thereffrom most conveniently although if the wad is left too long the efficiency of the system may be impaired.The time required to form the ideal wad of yarn in any given circumstances will depend upon the rate of comminution of the material to be comminuted. As soon as the wad 1 6 is released from the filter 12, the filter and tray assembly is slid back to the position shown by chain lines in the drawing where the collection of yarn thereby can be recommenced. It has been found in practice to be advantageous for the tray and filter assembly to automatically slidable by employing, for example, a control unit employing a solenoid valve. If solid material other than yarn is found to be present in a collected wad, then the gas stream created by the fan 9 is too powerful and gas must be bled into the chamber 2 by means of the gas balance valve 11. As has been aforementioned, some yarn passes through the filter 1 2 when the filter 12 is across the chamber 2, and the majority of yarn released during that time when the filter 1 2 is dumping a wad 1 6 will also pass upwardly through the chamber.

The released yarn latterly referred to is carried by the gas stream out of the outlet 7, along the pipe 13, and into the yarn collector 14.

This yarn settles at the bottom of collector 14 and may be collected as and when required.

As aforementioned, the comminuted solid material together with some yarn pieces fall, under the influence of gravity, out of the chamber 2 and into the transfer tray 1 7. The fan 20 along the length of the gas flow pipe 1 8 creates a gas stream which is sufficiently powerful to carry not only the yarn pieces but also the comminuted solid particles from the transfer tray 1 7 to the cyclone separator 19.

In the cyclone separator 19, the yarn pieces are carried by the gas stream into the yarn collector 25 via pipe 24. This yarn settles at the bottom of the collector 25 and can be collected as and when desired. The comminuted solid particles however, because of their comparatively greater weight, fall out of the influence of the gas stream and into the hopper 21. Solid material may then be transferred to the bag filling means 23 simply by opening the bag filling valve 22. If the hopper 21 is filled with comminuted solid particles, a bag may be filled without turning off the fan 20 since the solid particles act as a seal, but if the hopper does not contain that amount of solid, the fan 20 must be turned off during the filling of a bag.

It may be seen that the apparatus of the present invention enables convenient, and if desired continuous, extraction of reinforcing yarn or fibre from solid material reinforced thereby. The yarn or fibre and the solid material which have been separated thereby may then be reprocessed and re-used thus providing fresh raw material from a product which is normally discarded after its use.

Claims (14)

1. An apparatus for extracting yarn or fibre from a solid material containing such yarn or fibre as reinfforcement, including comminuting means for releasing said yarn or fibre from the solid material, and means for creating a gas stream for carrying the released yarn or fibre away from the comminuting means to a collector.

2. An apparatus according to Claim 1, wherein the comminuting means is present within a chamber having a gas inlet and a gas outlet for passage of the gas stream.

3. An apparatus according to Claim 1 or 2, wherein the collector is a filter positioned upstream of the comminuting means.

4. An apparatus according to Claim 3, wherein the filter is movable out of the gas stream for removal of the yarn or fibre collected thereon.

5. An apparatus according to any preceding claim, wherein the means for creating a gas stream is a fan.

6. An apparatus according to any preceding claim, wherein the comminuting means are rotating blades.

7. An apparatus according to any preceding claim, comprising a second yarn or fibre collector upstream of the first yarn or fibre collector.

8. An apparatus according to Claim 7, wherein the second collector comprises a settlement collector.

9. An apparatus according to any preceding claim, comprising secondary yarn or fibre separating means adapted to receive the comminuted material from which yarn or fibre has been carried away by the gas stream.

10. An apparatus according to Claim 9, wherein the secondary yarn or fibre separating means is a cyclone separator.

11. An apparatus for extracting yarn or fibre from a solid material, substantially as described with reference to, or as shown in, the drawing.

1 2. A method of extracting yarn or fibre from a solid material containing such yarn or fibre as reinforcement, which comprises comminuting said solid material to release the yarn or fibre and, at the same time, carrying away the released yarn or fibre in a gas stream to a collector.

13. A method according to Claim 12, wherein the gas stream is passed through a filter to collect the fibre.

14. A method of extracting yarn or fibre from a solid material, substantially as described.