WO1995019876A1

WO1995019876A1 - Device for dismantling steel-wire tyres

Info

Publication number: WO1995019876A1
Application number: PCT/EP1994/000180
Authority: WO
Inventors: Alexander Radijewitsch Bedjuch; Anatoli Lukitsch Luzenko; Tatjana Wassiljewna Parubotscha; Waleri Grigorjewitsch Butko; Stanislaw Iwanjwitsch Odinez
Original assignee: De Spiller, Dmitrij; MÜLLER, Elmar; Wunderlich, Alfred
Priority date: 1994-01-24
Filing date: 1994-01-24
Publication date: 1995-07-27
Also published as: AU5970494A

Abstract

A process for dismantling tyres with metal parts by separating the combined components rubber and metal in which the metal is heated by electric current. The metal components are briefly taken by the electric current to such a state that the boundary layers between the metal crystals evaporate and the vapour pressure thus generated pushes the solid metal particles explosively out of the surrounding rubber bed. The rubber body freed of the metal components is then reduced and the metal particles are collected. Device for dismantling tyres with metal inserts with a conveyor (34) and a downstream device for electro-thermally destroying the metal inserts and with a reducing device. The device for electro-thermal destruction has a pulse generator or diverter (56) connected via a connecting circuit (54) to a separator (72) acting on the tyres to separate the metal particles thermomechanically.

Description

Device for removing tires with a wire cord

description

The invention relates to a system for the removal of tires with a wire cord.

The storage and use of old tires is a major problem, if not used to manufacture retreaded tires, not least from an environmental perspective. The greater the industrialization and economy and the smaller the territory of a country, the greater the problem.

In many countries, used tires are burned to solve this problem. The proportion of burnt used tires is up to 45% in Germany and the Netherlands and up to 40% in Japan (cf. "Tire Recycling Plant Tires Up" in the Magazine "Modern Tire Dealer", 1987, No. 8, page 6). However, a major disadvantage of burning used tires is that toxic, in particular sulfur-containing substances are produced during combustion, which escape into the atmosphere, which is to be condemned from an ecological point of view.

For this reason in particular, it is advantageous to put used tires into the recycling cycle and to use them as secondary raw materials for the production of elastic products, for example materials for road construction, for roofing or for the production of seals.

The precondition for the use of old tires as secondary materials is the separation of the steel cord components from the rubber. In this connection, reference should be made, for example, to DE-OS 29 00 655, which relates to a method for separating rubber and metal components from steel cord tires. In this known method, the D ^~ are rahtbestandteile of the tire by means of electrical induction for a short time to about 400 ° C heated. The tires then go through a crusher, which, however, is exposed to very high mechanical loads because the heating only reduces the firm bond between rubber and steel, but the shredding and subsequent separation take place in the crusher and in a subsequent, magnetically operating separation system.

From DE-PS 30 39 870 a method and a device for separating rubber and metal are known, in which the metal is heated to an annealing, in order to separate the bond between metal and rubber in this way. Here, too, the starting product, for example used tires, is crushed beforehand so that the metal and rubber parts can be separated from one another after heating. The methods and devices explained have the disadvantage that a high energy expenditure is required for the dismantling and grinding of the tire provided with wire cord and only low outputs can be achieved.

Attempts have therefore been made to cool old tires to such low temperatures with liquid nitrogen that the rubber changes into a brittle, glass-like state and can be ground. After grinding, the components are separated. In another method, which is described in the magazine "Gummibereitung", 1987, volume 63, No. 10, pages 97 to 100, the tire is shredded with wire cord before freezing, so that after the freezing the fragments into metal parts and rubber be unlocked. Since liquid nitrogen is expensive, the process costs are very high. In addition, a large part of the rubber sticks to the metal, so that the metal is unusable for further use.

The invention has for its object to provide a method and an apparatus for dismantling tires with metal inserts, in which a great performance is achieved despite a low specific energy consumption.

In a process for the dismantling of tires with metal inserts by separating the components rubber and metal which are connected to one another, this object is achieved according to the invention in that the metal inserts are briefly brought to such a state by means of electric current that the boundary layers between the metal crystals evaporate and the resultant layer Vapor pressure explosively pushes the metal particles out of the surrounding rubber bed in the solid state, and that the rubber body freed from the metal is then mechanically crushed while the metal particles are collected. An electrical current density of at least 10,000 A / mm ² is preferably used to separate the metal particles.

The electrical energy can be supplied to the metal inserts either by direct contact or inductively.

To carry out this method, according to the invention, a device with a conveying direction and a downstream device for the electrothermal destruction of the metal inserts as well as with a comminution device is suitable, whereby according to the invention it is provided that the device for the electrothermal destruction has a pulse arrester or pulse generator which is connected via a connection circuit a separating element acting on the tire for thermomechanical separation of the metal particles is connected.

In the method and the device according to the invention, the metal inserts are excited by the electric current by means of an electric pulse of very short duration, so that only the boundary layers of the metal crystals are brought to the evaporation temperature without the metal and the rubber heating up appreciably. In this way, a partial degradation of the metal crystals takes place within a few microseconds, which are thrown explosively out of their seat in the rubber due to the resulting vapor pressure in the solid state. The metal particles thrown out of the rubber bed have dimensions of a few μm and can then be collected in a collecting vessel. What remains is the pure rubber body, which has been freed of metal and can be shredded for further processing.

Experiments have shown that the method and the device according to the invention achieve a very high energy yield, so that the energy losses are negligibly small. It is advantageous if the separating element is accommodated in a protective space which protects the operator against mechanical injuries caused by parts being thrown out and against noise.

According to a further feature of the invention, the connection circuit has a commutator and a power supply device.

In a first embodiment of the invention, a cutting device for separating the tire bead is arranged in front of the separating member, the separating member consisting of two contact elements which can be connected to the exposed metal inserts and which are displaceable relative to one another. To adapt the contact elements to the tires to be machined, it is advantageous if the contact elements are two frusto-conical plates, the smaller base areas of which face one another.

Furthermore, the pulse generator or pulse arrester has capacitors connected in parallel and in series, which can be referred to as a capacitor bank.

In this embodiment of the invention, the used tires are processed in front of the separating member in the cutting device in such a way that the two sides of the tire are separated so that the ends of the metal cord are exposed. The two contact elements of the separating member can then be placed on the exposed metal inserts, whereupon a very short electrical energy surge is conducted into the wire inserts via the pulse arrester. Such a device is simple and economical to manufacture and operate without sacrificing reliability. The frusto-conical plates ensure that perfect contact with the wire cord, even if the cutting is not completely uniform the tire sides is achieved so that the risk of incomplete dismantling of the cord network is reduced in individual zones.

In another embodiment of the invention it is provided that the pulse arrester or pulse generator is formed on the basis of a memory or coupling circuit with LC elements, the isolating element being the primary winding of a transformer, the secondary winding of which is formed by the wire cord.

In this variant of the invention, the complete tire, from which the sides do not have to be cut beforehand, is held lying on a support member made of non-ferromagnetic material. The electrical energy is introduced inductively into the metal cord, so that here too the metal inserts are shredded in the manner described above, the tire also tearing into pieces so that the metal particles are thrown out of the wire channels. This variant has the advantage that there is no need to cut off the side parts beforehand and that the energy pulses act on the entire metal insert via the electromagnetic field, so that the problem of recycling cut off side parts and beads is eliminated.

The primary winding should be in the central axis of the tire. Such an arrangement is particularly advantageous for dismantling large tires.

According to a variant, which is particularly useful for dismantling small tires, the primary winding itself serves as a support member and is detachably wound around the tire.

The invention is explained below using exemplary embodiments which are illustrated in the drawing. Show it: Figure 1 is a schematic representation of a first

Embodiment of a device according to the invention,

Figure 2 shows the enlarged view of the device according to

FIG. 1 cutting device used,

Figure 3 shows the enlarged view in the device according to

FIG. 1 device used for the electrothermal destruction of the metal,

Figure 4 shows a variant of Figure 3 and

Figure 5 shows a variant of the support member used in Figure 4 and the primary winding.

In the device for dismantling used tires 10 shown in FIG. 1, a conveyor 12 is indicated, which is equipped with hooks 14 on which the tires 10 to be dismantled hang. The tires 10 are individually fed to a cutting device 16, which is shown in more detail in FIG. It can be seen there that the cutting device 16 consists of a shaft 18 rotating about a horizontal axis, to the end of which a disk 20 is fastened, on which the tire 10 is held. In the upper area of the cutting device 16, two circular knives 22 are arranged, which are fastened to rotating shafts 24 arranged at an angle to one another. The angle enclosed by the two rotary shafts 24 can be adjusted in order to adapt to the shape and size of the respective tires 10.

With the help of the two circular knives 22, the two side parts 26 with the beads 28 are separated from each tire 10, so that the tread area 30 with the metal cord inserts 32 is available for further processing.

FIG. 1 further shows that the tread area 30, which is separated off in the manner described, is transported into a protective space 36 by a conveying device 34, for example a horizontal chain or belt conveyor. The protective space 36 consists of a metal or reinforced concrete housing with a floor 38, side walls 40 and a ceiling 42. On the side walls 40 Flaps 44 are schematically indicated, through which a tread area 30 to be machined with metal inserts 32 enters the protective space 36 or is conveyed out of it after the machining. In addition, it is also possible to design the floor 38 or the ceiling 42 to be displaceable in order to enable the supply and discharge.

The protective space 36 contains the separating element 72 provided according to the invention for the thermomechanical separation of the metal particles. For this purpose, a frustoconical plate 46 is mounted on the floor 38 of the shelter 36 so that its smaller horizontal base faces upwards. Another frustoconical plate 46 is arranged over the lower plate 46 so that the two smaller bases face each other. The top plate 46 is attached to a vertical bar 48 which can be slid upwardly with the plate 46 attached thereto to place the cut tread portion 30 of a tire between the two frustoconical plates 46 so that the ends of the cut ends exposed on the cut surfaces Metal inserts 32 touch the truncated cone surfaces of the two plates 46.

Figures 1 and 3 further show that the lower plate 46 is grounded via an electrical line 50, while the upper plate is connected via a line 52 to a connection circuit 54 which has a commutator, not shown, and a power supply device which is connected to the mains can be connected.

According to FIG. 3, the connection circuit 54 is connected to a pulse arrester 56 or pulse generator, which has a capacitor bank consisting of capacitors 58 connected in parallel and in series. The connection circuit 54 can also be coupled to a charging device (not shown) and a device for igniting the discharges. After the tread area 30 of an old tire lies between the two frusto-conical plates 46, a short discharge pulse is generated by the pulse arrester 56, which, due to the large voltage and current density and the large resistance in the metal inserts 32, causes local evaporation at the boundary layers of the metal crystals, so that the resulting vapor pressure throws the still solid metal particles out of the tread area 30. The metal particles detach themselves from the rubber bed surrounding them, so that channels corresponding to the wire diameter are created, through which the metal particles on both sides of the tread area 30 reach the outside. In the shelter 36 they mostly fall to the floor 38, from where they fall into a collecting vessel 62 via means and drain bores 60 (not shown). The tread area 30, now freed from the metal inserts 32, is transported out of the protective space 36 after the upper plate 46 has been lifted and arrives at a belt conveyor 64, which provides for a transport to further crush the tread area 30. In the explosion-like separation of the metal inserts 32 from the tread area 30, this or the tire 10 in the variant explained below may already have been divided into rubber pieces 66 which reach the belt conveyor 64.

In the variant shown in FIG. 4, the side parts 26 are not separated from the tires 10. Rather, the tire 10 is placed within the protective space 36, not shown here, on a centrally open support member 68 made of non-ferromagnetic material. The pulse arrester 56 is formed here on the basis of a memory or coupling circuit with LC elements (capacitors 58 and coils 74). The very short pulses reach the primary winding 70 of a transformer via the connection circuit 54, the secondary effect of which is formed by the metal inserts 32 of the tire 10.

The primary winding 70 lies with a coaxial course in the central axis of the tire 10 and induces in the secondary winding (Metal inlays 32) a discharge pulse generated by the reactive LC memory circuit of the pulse arrester 56 of very high current intensity and short duration, whereby the metal inlays 32 are opened up in the manner described and at the same time the rubber is torn into pieces 66 from which the metal particles are thrown out explosively. The rubber pieces 66 freed from the metal are fed on the belt conveyor 64 for further processing.

As the variant in FIG. 5 shows, the primary winding 70 itself can serve as a support member if it is wound around the tire 10 in the manner shown. In this case, the primary winding 70 must be detachable, for example through separation openings 76 indicated in FIG. 5.

Claims

claims

1. A method for the dismantling of tires with metal inserts by separating the interconnected components rubber and metal, the metal being heated by electric current, characterized in that the metal inserts are briefly brought into such a state by means of the electric current that the boundary layers between the metal crystals evaporate and the resulting vapor pressure explosively pushes the metal particles out of the surrounding rubber bed in the solid state, and that the rubber body freed from the metal is crushed while the metal particles are collected.

2. The method according to claim 1, characterized in that an electrical current density of at least 10,000 A / mm ^{2 is} used to separate the metal particles.

3. The method according to claim 1 or 2, characterized in that the electrical energy is supplied by direct contact.

4. The method according to claim 1 or 2, characterized in that the electrical energy supply takes place inductively.

5. Device for the removal of tires with metal inserts, in particular according to one of the preceding claims, with a conveyor (34) and a downstream device for the electrothermal destruction of the metal inserts and with a comminution device, characterized in that the device for electrothermal destruction comprises a pulse generator or pulse arrester (56), which is connected via a connection circuit (54) to a separating element (72) acting on the tire for thermomechanical separation of the metal particles.

6. The method according to claim 5, characterized in that the separating member (72) is housed in a shelter (36).

7. The method according to claim 5 or 6, characterized in that the protective space (36) is assigned a collecting vessel (62) for the excreted metal particles.

8. The method according to any one of claims 5 to 7, characterized in that the connection circuit (54) has a commutator and a power supply device.

9. The method according to any one of claims 5 to 8, characterized in that a cutting device (16) for separating the groove sides (26) is arranged in front of the separating member (72) and the separating member (72) from two to the exposed metal inserts (32) connectable contact elements, which are displaceable relative to each other.

10. The method according to claim 9, characterized in that the contact elements are two frusto-conical plates (46), the smaller bases of which face each other.

11. The method according to claim 9 or 10, characterized in that the pulse arrester (56) has capacitors (58) connected in parallel and in series.

12. The method according to any one of claims 5 to 8, characterized in that the pulse arrester (56) is formed on the basis of a memory or coupling circuit with LC elements and that the isolating member (72) is the primary winding (70) of a transformer.

13. The method according to claim 12, characterized in that the tire (10) is held lying on a support member (68).

14. The method according to claim 12 or 13, characterized in that the primary winding (70) in the central axis of the tire (10).

15. The method according to claim 12 or 13, characterized in that the primary winding (70) serves as a support member and is detachably wound around the tire (10).