FI69774C - SAETT OCH ANORDNING FOER ATT SOENDERDELA PLAST- OCH / ELLER GUMMIMATERIAL - Google Patents

Abstract

A method of disintegrating plastics and/or rubber material, such as the plastics and/or rubber casings of metal cores, for the purpose of recovering the metal from scrap cables for example. The material to be disintegrated is cooled to a temperature at which it becomes brittle. The embrittled material is then subjected in at least one station to mechanical oscillations which cause the material to disintegrate. The oscillations suitably have a frequency in excess of 30 Hz and an amplitude of about 2-3 mm. The oscillations can be imparted with the aid of a vibratory device with which the embrittled material is brought into contact.

Description

1 69774

Method and apparatus for biennialing plastic and / or rubber materials

The present invention relates to a method for grinding a plastic-5 and / or rubber material, such as plastic and / or rubber sheaths fitted to metal cores, wherein the material to be comminuted is cooled to a temperature where it becomes brittle and then subjected to comminuting mechanical vibrations. The invention also relates to a device for carrying out the method.

Efforts have long been made to provide a simple and rapid separation of rubber and plastic sheaths from metal cores, such as electrically conductive copper and aluminum cores, copper tubes, and the like, which not only allows complete separation of the sheath material from the metal core, but also simple and easy separation of components. so that both the metal and the sheath material can be reused.

In the past, the most widely used method has been to burn the mantle-20 base material. However, this method gives e.g. polluting air pollutants and is now banned. Besides, it also did not allow for the reuse of the sheath material. In connection with another known method, electrical cables are cut, i.e.

25 these are cut into such small parts that the insulating material largely falls automatically from the conductors. However, this method is relatively time consuming and expensive and causes major separation problems.

Both British Patents 30,303,167 and 1,407,996 describe methods in which the jacket base material is first cooled to a temperature at which it becomes brittle, after which it is subjected to mechanical treatment. One serious disadvantage of the device according to the first-mentioned patent 1,303,167 is its relatively complicated structure, comprising both an impact unit and a subsequent separation bar. If, for example, in some cases insufficiently cooled material enters this device, it will block the tough, sticky mass completely and this mass will be very difficult to remove. The risk of overheating of the cooled material also exists because a substantial portion of the kinetic energy produced by the hammer is converted into thermal energy in the jacket material. As a result of the need to use relatively short conductors, major separation problems still arise, especially in the case of thin metallic conductors, as a result of which the obtained metal and plastic material, respectively, do not have the desired quality (purity), which greatly reduces its value.

According to the aforementioned British Patent 1,407,996, a continuous conductor length is fed, the successive parts of which are treated periodically by means of a combined impact cutting head. This device has e.g. the following disadvantages. The processing speed remains low due to the intermittent mode of operation and the fact that only one wire can be processed at a time. The method is best suited for 20 thick cables, while it is hardly applicable to very thin cables or cables containing several separately insulated conductors. Furthermore, the impactor must be precisely adjusted to that cable dimension. The cable must also protrude in relatively large lengths.

The main object of the present invention is to provide a method and apparatus as described in the introduction which, while eliminating the above-mentioned drawbacks, allows plastic and / or rubber sheaths to be separated from metal cores, lengths, dimensions and number of cores in each article, and also allows handling of several objects. simultaneously.

The method according to the invention is characterized in that, as a result of cooling, the brittle material is subjected to comminuting mechanical vibrations so as to pass through a slit-like passage between two oscillating plates 3 69774 which are in contact with the material as it passes the plates. The vibrations consist of pressure waves or pulses of constant frequency, each of which does not have sufficient energy to crush the material, but which, when passed through it in the form of a substantially continuous mechanical vibration, results in it breaking down as a result of the vibrations occurring therein. . It is preferred that the amp-10 of the oscillations have a lithium of about 2-3 mm and a frequency exceeding 30 cycles per second.

The vibrations can be produced by means of a device characterized in that the means for subjecting the brittle material to mechanical vibrations comprise a vibrating plate arranged at a small distance from the solid base to form a slit-like passage through which the brittle material is intended to pass in contact with both the vibrating plate and the base. with. Furthermore, by utilizing the spring-suspended vibrating plate 20, the gap automatically adapts to the particular cable dimensioning, so that the same device can be used for alternating dimensions without the need for readjustment. Experiments have shown that the mechanical vibrations described above are efficiently transmitted in the cable or cable sheath between different insulating layers, so that the method according to the invention also effectively separates the insulating material from many conductor cables containing several different insulating sheaths and also handles bundles. The use of the invention further provides a substantially complete separation of metal and plastic, which, as described above, greatly increases the value of the products obtained.

In a particularly preferred embodiment of the device according to the invention, a vibrating plate suspended from springs arranged at opposite end edge portions thereof is used and the vibrations are applied to the plate closer to the springs attached to its other end edge part than to other springs, the plate being arranged so as to bring in the gap between the first end edge portion and the fixed base. This causes, among other things, that in connection with the diapers which are difficult to handle, the energy is stored in the rear springs, which energy is transferred at a certain exchange ratio to the front edge of the plate and causes an increased counterforce. It is further preferred that at least said front edge portion forms a certain angle with respect to the substrate, which makes it possible to provide continuous processing of the cable in a tapered gap, which is particularly important in the case of multiconductor cables.

Other features and characteristics of the invention will be apparent from the claims.

The invention will be explained in more detail below with reference to the accompanying drawing, in which Figure 1 is a plan view of an apparatus for shredding cable sheaths using the method of the present invention; Figure 2 is a fragmentary view of a vibrator according to the invention included in the apparatus of Figure 1.

In Fig. 1, the number 1 generally denotes a part of the orienting means provided with the cutting device 2. The alignment means comprises a plurality of rollers 3 cooperating with each other to orient the incoming cable 4. Such orientation means are well known and will not be explained in detail here.

o In practice, the alignment means 1 is turned 90 with respect to the one shown, so that the oriented and cut cable pieces 5 30 are oriented transversely behind the feed direction of the next cooling duct 6, as shown in the drawing.

The cooling duct 6 consists of an elongate insulating chamber 7 connected to a funnel-shaped inlet section 35 for disconnected cable splints 5. A rotary dosing-feeding device 9 is arranged in the inlet part 8 for feeding batches of cable pieces 5 into the cooling duct. The dosing feeder 9 cooperates with the piston member 10 for further feeding the cable pieces through the cooling duct. To facilitate this further transport of the cable pieces, the cooling channel 5 can form an angle with the horizontal.

A number of lines 11 open into the cooling duct 6, through which flowing nitrogen is fed from the tank 12. In order to provide efficient cooling of the cable pieces 5, a number of fans 13 are arranged to increase the gas circulation in the cooling duct 10. The number 14 denotes a suction blower for controlled evacuation of gas. Utilization of the dosing supply device 9 prevents uncontrolled wastage of the cooling medium.

The temperature of the cooling duct 6 is known by means of one or more temperature sensors 15, the number 16 denoting a converter which transmits an electrical signal corresponding to the known temperature, which is compared to a set temperature reference value 18 in the unit 17. The control unit 17 provides a control signal controlling 19. With this control device, the temperature in the different blocks of the cooling duct can be kept at the desired level.

From the cooling duct 6, pieces of cable 5, the sheaths of which are now brittle as a result of cooling, are fed to a device for comminuting sheathed sheath material. The shredding device comprises a vibrating unit 20, into which the rigid cable pieces 5 are fed by means of a piston member 21.

It can be seen from Figure 2 that the vibrating unit 20 comprises a vibrating plate 22 suspended by two front and two rear springs 23 and 24, respectively. These springs are in turn fixed to beams 25 which are pivotable at their rear ends about a fixed shaft 26. The front ends of the beams 25 are connected to each other by a rod 27 which, in connection with the height adjustment of the front ends of the beams, slides and is lockable 35 in the desired position in the slit-shaped openings in the stationary holders 28.

6 69774 A vibrator is arranged on the vibrating plate 22, which in this example is shown comprising two unbalanced flywheels 29 driven by an electric motor (not shown). By adjusting the weights and balance of the flywheels as well as the speed of rotation of the wheels, oscillations having the desired amplitude and frequency can be produced in a known manner. The vibrator may be located closer to the front springs 23 than to the rear 24.

The designation 30 denotes a stationary base, which at the rear end of the vibrator is transformed into a lattice formed of longitudinal rails 31. Below the grid 31, a container is arranged to receive the shredded sheath material, while at the end of the rail there is a container 33 for collecting the metal cores 34 of the cable pieces.

When using the shredder, a batch of oriented and cut cable pieces 5, cooled so that their sheaths are brittle, is fed by means of a piston member 21 into the slit-shaped opening between the vibrating plate 22 and the stationary base 30. The decreasing height of the gap-20 between the plate and the substrate provides for the sequential treatment of the sheath of the inserted cables as they pass through the gap. As a result of the sheath material being completely rigid, the vibrations produced by the vibrating plate 22 provide good propagation through the sheath material throughout the cables, which means that both the outer sheath and the individual sheaths around the individual conductors are effectively shredded by the vibrations in the material. The device also allows the processing of thin conductors in bundles, i.e. these can be fed in several layers.

30 As a result of the spring suspension shown on the plate 22 and the placement of the vibrator on the plate, difficult-to-handle or thick wires or large wire bundles are fed as the front end of the plate compresses the springs 23 and expands the springs 24. The energy then stored on the plate 22 with a dependence downwardly determined at a downward ratio 69774 in the form of a force acting on the front end of the plate. The increased reaction force thus obtained facilitates the operation of the plate as it shreds the sheath material of the imported cable pieces. In connection with the experiments, the vibrator has been placed on the plate 22 with good results, so that the ratio of the distances between the vibrator and the front and rear springs, respectively, has been 1: 4.

The spring suspension shown in the vibrating plate 22 thus allows the shredder to be utilized in connection with cables of varying diameters and provides an increased reaction force against thick cables or cables with a difficult-to-handle sheath. If very thick cables have to be handled, the front end of the plate 22 can be raised by means of the adjusting members 27 and 28.

The rotation of the vibrator flywheels 29 in the direction shown by those A provides automatic forward feeding of the cables 5 in the gap between the plate 22 and the base 30. Further, the oscillating movement of the plate 22 provides a blowing effect which effectively compresses the fine-sheathed sheath material through the grid formed of the rails 31 and down into the container 32.

Very good results have been obtained in the experiments using an amplitude of 2-3 mm and a frequency of 50 Hz for the oscillations of the plate 22. Despite this relatively low amplitude, good shredding power has also been achieved with relatively thick cable sheaths, which shows that in this case it is not a matter of conventional crushing but that the relatively high frequency is also crucial. The frequency should not be e.g. from a mechanical point of view, less than about 30 Hz, while frequencies above 50 Hz can also be used. The frequency of 50 Hz has been used in the experiments performed, as this is simple to achieve in practice when using an electric motor. As mentioned above, it is not a matter of conventional crushing of the material-35, but also the low power required. In the experiments described above, the vibrator has been used with a power of only 500 W with good results. However, higher power must be used to increase capacity. However, this remains very low in all conditions per kilogram of comminuted material compared to the power required in conventional equipment.

The low power further ensures that there is no risk of the jacket material overheating as the cable pieces pass through the vibrator. In practice, the heating has proved to be so low that several vibrators can be arranged in succession if desired.

A very essential advantage of the present invention is that a substantially 100% separation of the sheath material from the metal cores is achieved, as a result of which the value of both the obtained metal 15 and the sheath material is increased. The capacity also becomes very high because several pieces of cable are handled simultaneously and along their entire length. Furthermore, the device becomes very simple both in handling and structure, because e.g. no further adjustments are normally required for cable measurements on phase 20 TVs.

In connection with the embodiment shown, the cut cable pieces 5 are fed in the transverse direction. The length of the pieces is preferably about 1 meter. However, both longer and shorter cables can be treated according to the same principle.

It is also possible to feed several continuous cable lengths axially through the vibrator according to the invention. The cable can then possibly run from roll to roll as it passes through the cooling channel and the vibrating device according to the invention. In this case, the metal core is obtained with a continuous length of 30 and can possibly be used again without remelting.

The embodiment of the cooling duct described above can only be seen as an example, as this can be modified as desired. Furthermore, nitrogen gas can be exchanged for another gas depending on the desired cooling temperature determined by the jacket material. However, this is well known to those skilled in the art and will not be explained further here. The vibrating unit can also be modified in many respects and can, for example, be made movable with respect to a fixed base.

The utilization of vibrations for grinding plastic and / or rubber material according to the invention can be exploited not only for grinding cable sheaths but also for removing sheaths, e.g. from plastic-coated copper pipes and the like. Other objects can also be fine, such as car tires and the like. These are then first divided into smaller parts, which are cooled and then pass through a vibrating device according to the invention as a result of cooling in order to grind the brittle rubber material.

The invention can also otherwise be modified in several respects, in which case all embodiments have in common the utilization of mechanical vibrations by cooling to grind the brittle rubber and / or plastic material. The vibrations can then be produced by means of a vibrating device or in another way, e.g. by strong air pressure pulses or the like.

Claims (6)

A method of disintegrating plastic and / or rubber materials, such as metal and / or rubber casings applied to metal cores, the material to be disintegrated being cooled to a temperature at which it becomes brittle, and then subjected to disintegrating mechanical oscillations, characterized in that the material which is broken down by cooling is imparted to the disintegrating mechanical oscillations by passing through a slit-shaped passage between two relatively oscillating plates which abut the material during its passage of the plates. 2. A method according to claim 1, characterized in that the material is subjected to oscillations having an amplitude of about 2 ... 3 mm and a frequency exceeding 30 periods / second. 3. Device for disintegrating plastic and / or rubber materials, such as onto metal and / or rubber casings 20, including metal (6) for cooling the material to be decomposed to a temperature at which it becomes brittle and (20) thereafter subjecting the material to disintegrating mechanical oscillations, characterized in that the means (25) for exposing the brittle material to mechanical oscillations comprise a vibrating plate (22) arranged at a small distance from a solid support (30), therebetween to form a slit-shaped passage through which the brittle material is intended to pass in contact with the vibrating plate as well as the substrate. 4. Device according to claim 3, characterized in that the vibrations of the plate (22) have an amplitude of about 2 ... 3 mm and a frequency exceeding 30 periods / second. 5. Device according to claim 3 or 4, characterized in that the vibrator plate (22) is provided.