DE9114085U1 - Device for pulverizing old tires and other rubber and plastic objects - Google Patents

Description

DR. G. HARTMANN Patent Attorney

DIPLOM-C H ^- E MIKER EUROPEAN PATENT ATTORNEY

Registered with the German and European patent authorities PA DR. G. HARTMANNhPienzenauorstrasse2fD-8000 MÖNCHEN

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MUNICH,

27 December 1991

Applicant: Walter Iten

Dörfli 20 CH-6343 Risch-Rotkreuz

Device for pulverizing old tires and other rubber and plastic objects

The invention relates to a device for pulverizing old tires and other rubber or plastic objects, in which the old tires or other objects are pulverized as a whole in one operation by dry grinding 3 5 and then sent for further use.

The ever-growing mountains of tires and plastics represent a major threat to the environment. Although there are ways to recover the valuable raw materials they contain, their technical application has so far failed due to lack of economic viability. Reusing used tires and other plastic items by completely renewing them may make sense, but it is not an environmentally friendly solution in the long term.

As is well known, only 2% of car tires and other rubber and plastic items can be destroyed in waste incineration plants because of the high combustion temperature of around 2000 ⁰ C required and because of their high pollutant content. On a smaller scale, conventional shredding plants shred tires into palm-sized pieces that can be burned more easily.

It is also already known that old tires can be shredded into larger pieces in shredding plants using knife-like devices in order to be able to store them more easily in landfills.

Attempts have already been made to industrially process old tires and other rubber and plastic items. However, high energy, labor, equipment and construction costs have not yet allowed for economic utilization.

Since 1990, there have been strict regulations in place for incineration plants in Germany regarding the emission of dioxin and furan, which must not exceed 0.1 ng per m ³ of exhaust air. This new regulation requires extremely expensive flue gas cleaning systems and old plants must be converted accordingly by 1993. The question of what happens to the highly toxic filters and their residues also remains unanswered.

To get an idea of the environmental problems this creates, you have to remember that in Germany alone more than 550,000 metric tons of used tires were produced in 1990. Landfills and other disposal options no longer exist and interim storage facilities have long since reached their capacity limits. In the USA, 1,200,000 metric tons of new tires are produced annually. These are not biodegradable and have an extremely high chemical resistance, so that their lifespan is almost unlimited.

A process for pulverizing old tires is already known from DE-OS 2 417 711, in which the old tires are first shredded in a coarse chipping machine and then shredded again in a fine chipping machine and the metal parts are removed using magnets. A pulverizing machine then processes the metal-free old tires into powder with the desired grain size.

The disadvantage of this process is that several machines are required in series, which require relatively high investment costs, take up a lot of space and require complex control systems to ensure trouble-free operation of the machines connected in series.

DE-OS 30 48 405 describes a process in which the tread of an old tire is converted into rubber powder by grinding, while the associated carcass is separated and used as reinforcement in the construction industry. The tire must be cut up before grinding and fed into a grinding machine. The carcass and the steel insert remain after the process has been completed and must be recycled separately.

The disadvantage of this process is that only a portion of the old tire is pulverized for further use and the carcass and steel insert must be recycled separately for special purposes. In addition, this process is complicated and involves a lot of effort.

A device for shredding vulcanized rubber is known from Swiss Patent Specification 43 806, in which rubber pieces are shredded in a rotating container, the inside of which has sharp projections. If you want to shred old tires in such a device, the metal parts must first be removed from the old tire, which involves great technical and economic effort.

The object of the invention was therefore to create a method and a device for pulverizing old tires and other rubber or plastic objects that are technically simple and economical and provide reusable end products.

It was found that this object can be achieved according to the invention by introducing the old tires or rubber or plastic objects under pressure by means of a conveyor and delivery shaft into a process chamber with one or more oscillating and rotating grinding bodies in it, in which a problem-free and trouble-free pulverization of the old tire or the plastic object takes place with cooling by means of cold air in a closed circuit, even if it contains metal parts. The rubber or plastic parts and any textile and metal parts present are then separated from one another and sent for further technical utilization.

The invention relates to a method for pulverizing old tires or other rubber or plastic objects, in which the old tires or other objects are pulverized as a whole in one operation by dry grinding or grinding and then fed for further use, which is characterized in that

a) the old tires or other objects are transported in a closed conveyor shaft and then are fed upright or lying down on driven spiked rollers in a narrowing delivery shaft, individually or in series next to one another, into a closed process chamber, whereby each old tire or other object is increasingly deformed (compressed) in the delivery shaft that narrows towards the process chamber,

b) each pressed old tyre or other object entering the process chamber is pressed against one or more cylindrical grinding wheels, preferably double grinding wheels, each oscillating and rotating on an axis and ground into a powder while cooling with cold air of e.g. -20 ⁰ C in a closed circuit,

c) the powder accumulating in the process chamber is removed and separated in a separating device into rubber powder parts or plastic powder parts and, if necessary,

Metal powder parts and textile powder parts are separated electrostatically and by air sifting and transferred to silos for storage of the different powder parts.
35

The delivery shaft used in stage (a) preferably has left and right or top and bottom

Individually or jointly driven spiked rollers extending over the entire width or height of the conveyor shaft feed the feed material into the process chamber under pressure.
5

The spiked rollers are preferably driven by a chain drive using pinions, or the individual spiked rollers are driven by electronically controllable electric motors.
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The feeding speed of the old tires or other objects is preferably continuously and infinitely adjustable.

The grinding body(s) in the process chamber is (are) preferably arranged so as to be rotatable on a rotation axis and to be able to move back and forth laterally perpendicular to the conveyor shaft and is designed as a so-called oscillating rotary grinding body(s).

The cylindrical grinding body(s) used according to the invention preferably consists of several segments made of different materials, in particular sintered materials with a surface made of silicon, electrocorundum, silicon carbide, cubic boron nitride and/or industrial diamonds and/or the segments have different surface grains for grinding different components of the old tire or the other objects.

Preferably, the segments of the grinding body(s) are connected to one another via rubber seals arranged between them, preferably neoprene plates.

The grinding bodies that can be used according to the invention can also consist of a cast metal or steel roller that has parallel,

replaceable diamond grinding belts with preferably a dovetail-shaped cross-section.

According to a preferred embodiment of the invention, the rubber or plastic powder particles and the metal powder particles are separated from one another in the separating device by electrostatic means and by air sifting.

The invention further relates to a device for carrying out the method described above, which is characterized by

a closed conveyor and delivery shaft with driven spike rollers for introducing the old tires or rubber or plastic objects under pressure into the process chamber,

a process chamber with one or more axially mounted, rotatable cylindrical grinding bodies arranged therein, which can be moved in an oscillating manner perpendicular to the conveyor shaft along the axis of rotation, and

a device for separating the rubber or plastic powder particles, the textile fabric powder particles and any metal powder particles from each other.

According to a preferred embodiment of the invention, the grinding body(s) in the process chamber consists of several cylindrical segments made of different materials and/or with different surface grains, with rubber seals, preferably neoprene plates, being arranged between the individual segments if the segments consist of a ceramic material.

In another embodiment of the invention, the grinding body(s) in the process chamber consists of one or more cylindrical, rotatably mounted grinding bodies arranged along the

Cast metal or steel roller(s) that can be moved back and forth in an oscillating manner on the axis of rotation, on whose circumferential surface replaceable industrial diamond grinding belts with a dovetail-shaped cross-section are attached, arranged horizontally or vertically parallel to one another.

According to the invention, it is possible, even in small and medium-sized companies, to recover the raw materials contained in old tires or rubber and plastic objects in a technically simple and economical manner, whereby the invention enables a precise separation of rubber, steel and textile particles.

In the device according to the invention, car, truck and other special and extreme tires can be ground into their segments or into the finest segment powders with a particle diameter of about 0.1 mm by means of a pro-mechanical drive. The heat generated during the grinding is dissipated by cooling with cold air, which has a temperature of -20 ⁰ C, for example, in a closed circuit. The cold air supplied from outside is blown into the process chamber, where it heats up, extracted from there again and cooled down outside the process chamber to the initial temperature (e.g. -20 ⁰ C) before being fed back into the process chamber in the circuit.

The device according to the invention is extremely easy to operate and one person is sufficient to monitor it. The system according to the invention can be continuously on and off, so that it works economically even with very small quantities. On the other hand, the system according to the invention allows the pulverization of steel belt tires in quantities of up to 220 kg/min with little energy consumption. The total energy consumption of a small system is less than 100 kW/h.

The system according to the invention makes it possible to completely recover the raw materials contained in old tires and other rubber and plastic objects in an environmentally friendly manner. The particle fineness and material purity that can be achieved in this way means that the material obtained can be reused for high-quality technical products.

The powder obtainable according to the invention can be reused for the production of corresponding objects (tires, molded bodies). It is particularly suitable for the production of impact-resistant underbody protection for motor vehicles and for the production of elastic bumpers on vehicles, in particular the outside of ship hulls.

The invention is explained in more detail below using the example of the pulverization of used tires with reference to the accompanying drawings. They show: 20

Fig. 1 shows the sequence of the overall process according to the invention in a plant according to the invention with its essential parts in a schematic representation;
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Fig. 2 shows the feeding and pulverizing device of the overall system according to the invention in an enlarged view;

0 Fig. 3 a schematic representation of the conveying and

Delivery shaft of the device according to the invention in an enlarged view;

Fig. 4 shows the schematic structure of the delivery shaft of the device according to the invention in

again enlarged representation;

Fig. 5 shows the essential parts of the process chamber of the device according to the invention, in which the rubber or plastic objects are pulverized;

Fig. 6 shows an embodiment of the grinding bodies arranged in the process chamber in a schematic representation on an enlarged scale; and

Fig. 7 shows another embodiment of the grinding bodies arranged in the process chamber in schematic

ical representation on an enlarged scale.

In the exemplary embodiment of the method according to the invention in the device according to the invention shown in Fig. 1, the numbers 1 and 2 (bordered part top left in Fig. 1) designate the device for introducing the old tires delivered by truck and the adjoining process chamber with grinding devices. The powder accumulating in the process chamber 2 is separated after transport by means of the conveyor devices 3 and 4 in the separating device 5 (magnetic separation) into metal or steel powder on the one hand, which is collected in the containers 6, and into abrasive body dust, textile material powder and rubber powder on the other hand, which are transported by means of the conveyor device 7 into the container 8, from which they are transported via the device 11 (wind sifting) by means of a blower 12 into the loading silos 13 after the heaviest particles (e.g. ceramic dust) have been removed at 10 and the light powder components (e.g. textile parts) at 9, from which they are transported away separated according to material properties, e.g. as rubber powder, in the transport devices 14 and 15 for further use.

The order of powder separation by e.g. magnetic separation and air separation can also be reversed.

Fig. 2 shows an enlarged view of the feeding device with subsequent pulverization device according to the present invention in a schematic representation on an enlarged scale.

In the embodiment shown, old tires 23 of different sizes are fed from above through two separately feedable conveyor shafts 21, 22 into two parallel delivery shafts 24, 25, in which the tires 23 are fed by means of driven transport rollers into the downwardly tapering delivery shafts 24, 25 under pressure and with increasing deformation into the process chamber 26 with one or more grinding bodies 27 arranged therein.

From Fig. 3, in which the conveyor shaft and delivery shaft are shown schematically in section on an enlarged scale, the conveyor device 30 can be seen, with the help of which the tires 33 are transported in the conveyor shaft 31 to the end of the conveyor shaft 31, whereby an undesirable rolling back of the conveyed tires is prevented by suitable retaining devices 32 at suitable intervals. When they reach the end of the conveyor shaft 31, the tires are held back by means of a suitable sensor device (not shown) until the tires conveyed under pressure in the delivery shaft 34 into the process chamber have been ground by the two grinding bodies 37, 38. The lock at the end of the conveyor shaft (31) is then released by means of a suitable sensor device (not shown), so that further tires can reach the delivery shaft 34.

In the embodiment shown, the two cylindrical grinding bodies 37, 38 arranged in the process chamber are on axes arranged parallel to one another

arranged to rotate, with both grinding bodies 37, 38 rotating in opposite directions to each other and in opposite directions to the tire fed into the feed shaft 34. At the same time, the two grinding bodies 37 and 38 are displaced against each other in the axial direction, so that an overall oscillating rotational movement is created, which ensures that the tire fed through the feed shaft 34 comes into contact with constantly changing surfaces of the grinding bodies 37, 38.

Fig. 4 shows the delivery shaft of the device according to the invention in an enlarged view. The delivery double shaft 41, 42 shown, which tapers towards the process chamber, has spiked rollers 43 on the opposing surfaces, which are individually driven by electric motors and ensure that the tire to be ground is transported under pressure into the process chamber. In this case too, the spiked rollers on the opposing surfaces of the delivery shaft 41, 42 rotate in opposite directions to one another in such a direction that the supplied tire is transported into the process chamber.

Fig. 5a shows a schematic representation of the introduction of the tire to be ground into the space between the counter-rotating grinding bodies 51, 52, of which the grinding body 52 has the shape shown in Fig. 6.

Fig. 5b shows the two grinding bodies 51, 52 shown in cross section in Fig. 5a in a representation in longitudinal section, from which the oscillation movement of the two grinding bodies 51 and 52 against each other can be seen.

Fig. 5c shows one of the two grinding bodies 51, which is mounted on a rotatable axis 53 and can be moved by means of a motor 54 that runs on rails.

The grinding bodies that can be used according to the invention can be set in rotation with axle motors (not shown) and can be moved against each other in the axial direction with drive motors (also not shown). The grinding bodies can consist of a drum roller made of steel or cast metal, which can be made from one piece or from several parts. Such drum rollers generally have a diameter of between 200 and 1000 mm, preferably about 800 mm. They can be made up of segments that are 50 to 200 mm, preferably 100 to 150 mm wide, with a segment generally weighing about 120 kg. The individual segments can be connected to each other by suitable toothing or doweling so that they do not move against each other when the drum roller rotates.

The length of the drum roller is usually 300 to 3000 mm, preferably 1500 mm.

The cylindrical grinding bodies that can be used according to the invention can consist of a ceramic material with a suitable surface grain. In this case, the cylindrical grinding body can consist of individual block segments, between which rubber seals, preferably neoprene seals, with a thickness of preferably 2 mm are arranged in order to avoid undesirable wear of the ceramic material due to movement of the individual block segments against each other. The surface of the grinding bodies made of ceramic material preferably consists of silicon, electrocorundum or silicon carbide. Their surface can also be galvanically coated, for example with cubic boron nitride and/or industrial diamonds.

The two cylindrical grinding bodies, as preferred according to the invention, rotate against each other, as a rule, with a surface speed of, for example, 5 to 30 m/s, preferably 10 to 15 m/s. The oscillating

The length of the grinding wheel, i.e. the distance over which the two grinding wheels move against each other in the axial direction, is usually about 100 cm (measured from the center of the grinding wheel).
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The distance between the counter-rotating cylindrical grinding wheels is usually about 0.5 to 10 mm, preferably 1 to 3 mm, especially 2 mm.

If the grinding bodies used according to the invention are made up of segments, their width is generally between 50 and 200 mm, preferably between 100 and 150 mm. A grinding body preferably consists of 3 to 15, particularly preferably 7 segments, whereby if the grinding bodies consist of ceramic material, rubber seals, preferably neoprene seals, with a thickness of preferably 2 mm, are arranged between the individual segments.

The drum roller 61 shown in Fig. 6a can be made of steel or cast metal. It is usually hollow inside. Before use, it is surface-treated by galvanic plasma coating for spraying on industrial diamonds and/or cubic boron nitride to achieve a surface grain of 4/10 to 8/10, preferably 8/10 (with cubic boron nitride) or of 0.5 to 1.5 carats, preferably 1 carat, when a coating with industrial diamonds is used.

0 However, it is advisable not to coat the entire surface of the round roller 61, but to provide grooves 64 with a dovetail-shaped cross-section in the surface, into which strip-shaped tools 62 with a suitable surface coating 65, as shown in Fig. 6b, can be inserted. In this way, the coating of the surface of the drum roller 61 can be applied in the event of any

Damage can be repaired locally without having to remove the entire drum roller.

Fig. 6c shows a ready-to-use drum roller 63 with coated tools 62 inserted into the grooves.

In the surface of a drum roller 61, as shown in Fig. 6a, depending on the size, up to 100 strip-shaped tools 62 can be inserted into the grooves 64, whereby these strip-shaped tools 62 can extend over the entire length of the drum 61 or only over a part of it.

The embodiment of the grinding bodies usable according to the invention shown in Fig. 7 shows a cast steel wheel 71 with a special coating 72. In this case, the special coating of the highly stressed surfaces can be applied by galvanic coating, which can be reinforced by plasma spraying, powder flame spraying and/or arc spraying.

The cast steel wheel 71 with galvanic surface coating 72 shown in section in Fig. 7 A-A expediently consists of individual grinding wheels (Fig. 7 B-B) which have been coated on their peripheral surface to a thickness of preferably 2 mm in the manner described above. The individual grinding wheel discs 73 shown in Fig. 7 B-B are pushed onto the running axle 74 and preferably interlocked with one another by means of a tongue and groove. The running axle 74 with the pushed-on grinding wheel discs 73 is then pushed onto the fixed axle 75, on which it is rotatably mounted.

Although the invention has been explained in more detail above using preferred embodiments, it is by no means limited to them. Rather, within the scope of the

Any changes and modifications within the scope of the present invention may be made without departing from the scope of the present invention.

Claims (1)

Protection claims 1. Device for pulverising old tyres or other rubber or plastic objects, in which the old tyres or other objects are pulverised as a whole in one operation by dry grinding and then submitted for further use, characterised by a closed conveyor shaft with an adjoining delivery shaft with driven spiked rollers for introducing the old tires or rubber or plastic objects into the process chamber under pressure, a process chamber with one or more axially mounted rotatable cylindrical grinding bodies arranged therein which can be displaced against each other perpendicular to the feed shaft, and a device for separating the rubber or plastic powder particles, the textile fabric powder particles and any metal powder particles from each other, preferably by air sifting and electrostatically. 2. Device according to claim 1, characterized in that the feed shaft has driven spiked rollers on the left and right or above and below extending over the entire width or the entire height of the shaft in order to feed the feed material under pressure into the process chamber. 3. Device according to claim 1 or 2, characterized in that the spiked rollers are driven on pinions by means of a chain drive together or individually by electronically controllable electric motors. l8 4. Device according to one of claims 1 to 3, characterized in that the grinding body(s) in the process chamber is (are) mounted so as to be laterally movable back and forth on the axis of rotation perpendicular to the conveyor shaft and oscillate against each other. 5. Device according to one of claims 1 to 4, characterized in that the grinding body(s) in the process chamber consists of several segments made of different materials and/or with different surface grains and that in the case of ceramic-bonded grinding wheels, neoprene plates are arranged between the individual segments. 6. Device according to one of claims 1 to 5, characterized in that the grinding body(s) in the process chamber has replaceable industrial diamond grinding belts arranged horizontally or vertically parallel to one another on the peripheral surface. 8. Method according to one of claims 1 to 6, characterized in that the grinding body has interchangeable industrial diamond grinding tools arranged parallel to one another on its peripheral surface. 9. Method according to one of claims 1 to 8, characterized in that in the separating device the rubber or plastic powder particles and the metal powder particles are separated from one another by electrostatic means and by air separation. 10. Device for carrying out the method according to one of claims 1 to 9, characterized by a closed conveyor shaft with an adjoining delivery shaft with driven spiked rollers for introducing the old tires or rubber or plastic objects into the process chamber under pressure, a process chamber with one or more axially mounted rotatable cylindrical grinding bodies arranged therein which can be displaced relative to one another perpendicular to the feed shaft, and a device for separating the rubber or plastic powder particles, the textile fabric powder particles and any metal powder particles from one another, preferably by air sifting and electrostatically. 11. Device according to claim 10, characterized in that the feed shaft has driven spiked rollers on the left and right or above and below extending over the entire width or the entire height of the shaft in order to feed the feed material under pressure into the process chamber. 12. Device according to claim 10 or 11, characterized in that the spiked rollers are driven on pinions by means of a chain drive jointly or individually by electronically controllable electric motors. 13. Device according to one of claims 10 to 12, characterized in that the grinding body(s) in the process chamber is (are) mounted so as to be laterally movable back and forth on the axis of rotation perpendicular to the conveyor shaft and oscillate against each other. 14. Device according to one of claims 10 to 13, characterized in that the grinding body(s) in the process chamber consists of several segments made of different materials and/or with different surface grains and that, in the case of ceramic-bonded grinding wheels, neoprene plates are arranged between the individual segments. 15. Device according to one of claims 10 to 14, characterized in that the grinding body(s) in the process chamber has (have) replaceable industrial diamond grinding belts arranged horizontally or vertically parallel to one another on the peripheral surface.