FR2946275A1 - METHOD AND INSTALLATION FOR DECHICKS OF USED PNEUMATIC TIRES - Google Patents

Abstract

According to a method of shredding used tires, at least one rotating head (15) producing multiple ultra-high pressure jets to the surface (Se, Si) of a tire (P) to be shredded is used, and during a step shredding, the rotary head (15) is moved relative to the surface of the tire (P), the method being characterized by moving the rotating head (15) along a defined path according to the measured geometry of the tire ( P). Installation implementing the method.

Description

Process and installation of shredding used tires. FIELD OF THE INVENTION The invention relates to a method and a shredding plant of used tires, in particular by the use of ultra high pressure liquid jets. PRIOR ART Such a method and such an installation make it possible to separate the materials constituting a tire in order to recycle or reuse at least some of the materials. Such an installation is described in particular in document Dl (US 5,341,996). It includes a means for maintaining and rotating a tire, and a means for projecting fluid jets on the tire to be treated. The projection means comprises a plurality of projection heads each comprising an axis of symmetry. The projection means also comprises a means for orienting the axis of symmetry of the heads perpendicular to the surface of the tire to be treated and for rotating the heads about their axis of symmetry. On the periphery of the heads, on the same radius, are positioned a plurality of outlet nozzles which direct pressurized fluid jets in a direction perpendicular to the tire to be treated or at an angle in order to treat surfaces of the tire to be treated which do not pass directly under the projection heads. Such an installation makes it possible to separate the metal parts of the fabrics and rubbers of the tires used, but it is not very efficient. The particles of material torn from the carcass of the tires are rather coarse and consequently

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quite difficult to recycle. In addition, many passages are often required to remove all tissue and rubber particles. In addition, the system is set for tire models with similar dimensions. For tires outside this model, a different adjustment of the installation must be made. OBJECTS OF THE INVENTION The invention aims at providing a method of shredding used tires by using ultra-high pressure liquid jets which makes it possible to obtain good productivity, with an ability to adapt to many models. of tires.

The invention also aims to provide an installation implementing the method. SUMMARY OF THE INVENTION With these objectives in view, the subject of the invention is a method of shredding used tires according to which at least one rotating head producing multiple ultra-high pressure jets is used towards the surface of a tire to be shredded. and, during a shredding step, the head is moved relative to the tire surface. The head is moved along a defined path according to the measured geometry of the tire. By implementing such a method, tires of different geometries and sizes can be processed successively on the same installation. In addition, by following the profile of the tire, one can place the rotating head closer to the tire surface, which ensures the greatest efficiency during the chipping operation. Indeed, as soon as the distance between the head and the surface to be treated increases, the impact power of the jets decreases rapidly. The

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productivity of the facility is thus high. The rotation of the heads makes it possible to have circular paths to the jets and to scan, in combination with a movement of advance between the head and the tire, a band in which the jets make a spiral trace on the surface of the tire. In a particular way, an acquisition step is carried out before the shredding step, during which the external geometry of the tire to be shredded is measured and a trajectory of the head is deduced for the shredding operation. By separating the measurement and shredding operations, optimal conditions are maintained for carrying out the measurements. Indeed, the measurement operations are not disturbed by the difficult conditions of the shredding operation during which liquid and rubber or fabric particles are projected into the environment around the tire.

In a particular implementation, a series of measurement points of the tire surface is acquired, and a profile function is calculated as an interpolated curve between the points. Using an interpolated curve makes it easier to determine the trajectory for the rotating head. The interpolated curve is for example a spline. This type of modeling is widely used and is even implemented in some industrial automata.

According to an improvement, during the shredding operation, the head is oriented according to a normal to the interpolated curve. The jets produced by the head attack the surface at a controlled angle that ensures shredding efficiency.

In a complementary manner, a measurement of the geometry is also carried out during the acquisition step.

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inside the tire. This measurement of the geometry can then be used as explained below. For example, the inner thickness and the outer geometry are deduced from the local thickness of the tire and consequently the feed rate for the shredding operation. The speed of advance, at which the tire passes in front of the rotating head, must not exceed a limit value in order to allow time for the jets to shred the tire throughout its thickness. By determining the thickness of the tire to be treated, this limit can be calculated and the feed rate adjusted in order to optimize the cycle time while ensuring that the treatment is operated correctly and in a single pass.

The invention also relates to a tire shredding installation comprising at least one rotating head for producing multiple ultra-high pressure jets towards the surface of a tire to be shredded, and means for moving the head relative to the surface. of the tire. It further comprises means for measuring the geometry of the tire and means for determining a trajectory for the head defined as a function of the measured geometry. In particular, the measuring means comprise at least one movable arm carrying a non-contact distance measuring cell. By controlling the position of the arm, we know its position. Measuring the distance between the measuring cell and the surface of the tire, combined with the knowledge of the position of the arm, makes it possible to determine the position of a point on the surface of the tire. It is thus possible, by moving the arm, to scan a portion of the tire surface to determine its geometry. According to an improvement, the movable arm also supports one of the rotating heads. The same arm is thus used for the measurement and for the displacement of the head for the shredding operation. According to a constructive arrangement, the installation comprises a mandrel for mounting the rotary tire about its axis of symmetry, the movable arm being able to move in a radial plane containing the axis of rotation of the tire. The chuck is used to grip tires of different sizes. The rotation of the tire can be obtained by the rotation of the mandrel itself, or by the driving of the tire by rollers bearing on a circular surface of the tire. By the combination of the rotational movement of the tire and the displacement of the movable arm in a radial plane, it is possible to cover the entire surface of the tire.

According to a particular arrangement, the installation comprises two outer movable arms for measuring and shredding the outer surface of the tire, and an inner movable arm for measuring and shredding the inner surface of the tire. With these means, a high productivity is ensured in the shredding operation. In particular, the rotating head is pivotally mounted about a pivot axis perpendicular to the radial plane. It can thus orient itself with respect to the surface of the tire to follow a profile of the tire in the radial plane. BRIEF DESCRIPTION OF THE FIGURES The invention will be better understood and other features and advantages will appear on reading the description which follows, the description referring to the appended drawings in which: FIG. 1 is a perspective view of a installation according to the invention; - Figure 2 is a top view of the installation of Figure 1 Figure 3 is a perspective view of the end of a movable arm carrying a measuring cell and a rotating head. DETAILED DESCRIPTION A tire shredding installation 1, as shown in FIGS. 1 and 2, comprises a frame 11 on which cowls are mounted, in order to delimit a substantially closed enclosure 10. A mandrel 12 is pivotally mounted on the frame 11 about a vertical axis M. It is able to grip a tire P outside the enclosure 10 and to introduce it into the enclosure 10 by pivoting it substantially a half turn. The mandrel 12 comprises three spacers 120 which engage with an inner ring C1 of one of the flanks F1 of the tire P. The mandrel 12 does not maintain the other sidewall. Each spacer 120 comprises a motor 121 driving a roller 122. The three rollers 122 have axes of rotation G parallel to each other and comprise V-shaped grooves to receive the strapping C1 and to drive in rotation at a controlled speed the tire P around its axis of symmetry S, placed horizontally. The other sidewall F2 is not maintained by the mandrel 12, but by several grooved rollers, not shown, rotatably mounted about axes parallel to the axis of the mandrel 12 and mounted movable in translation to bear against the strapping C2 of said flank F2. The installation 1 comprises a first carriage 13 movable in translation in a horizontal direction D1 and perpendicular to the axis of the mandrel 12 when the mandrel 12 holds the tire P in the enclosure 10. The displacement of the first carriage 13 is motorized. Two outer movable arms 131, 132 are slidably mounted on the first carriage 13 in a direction D2 horizontal and perpendicular to the direction of translation of the first carriage 13, and set in motion by electric motors. Each arm comprises at its end a measuring cell 14 and a rotating head 15 mounted on the same support 133, 134, which support 133, 134 is pivotally mounted along a vertical axis V and motorized. Each measuring cell 14 is housed in a chamber, which chamber is closed on command by a flap 140 mounted slidably. The measuring cell 14 is able to make an optical distance measurement between its marker and a surface that it aims. Each rotating head 15 is rotatably mounted about a head axis T oriented in the same direction as the direction of sight of the cell. The rotating head 15 is able to generate jets of liquid in directions substantially parallel to the head axis T. The installation 1 further comprises an inner movable arm 16. The inner movable arm 16 also comprises a measuring cell 14 and a rotating head 15 mounted on the same pivoting support for shredding the tire surface P from the inside. The inner movable arm 16 comprises a first member 161 slidably mounted in a direction parallel to the axis of the mandrel 12 on a second carriage 17. The second carriage 17 is slidably mounted along a horizontal axis and perpendicular to the axis of the mandrel 12. The inner movable arm 16 further comprises a second member 162 pivotally mounted on the first member 161 about a vertical axis. The second member 162 is telescopic and carries at its end the pivoting support 163. The pivoting and elongation of the second member 162 allows to introduce and extract the support inside the tire P. Operation of the installation All the motorized elements are controlled by a

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central unit such as an industrial programmable controller, not shown, which controls the entire installation 1. The operation is fully automated and does not require human intervention.

A tire P is in front of the mandrel 12. The mandrel 12 advances and moves the spacers 120 to grip the tire P. Then the mandrel 12 pivots around a half-turn on the vertical axis M to bring the tire P working position. The flaps 140 of the measuring cells 14 open and the movable arms 131, 132, 16 are moved around the tire P to scan the entire profile of the tire P, outer side Se and inner side Si. During this phase, the pneumatic P is rotated by the rollers 122 of the mandrel 12 to verify that any deformation of the geometry of the tire P remain within acceptable tolerances. From a set of measurement points distributed on the profile, the automaton interpolates a curve in the form of a spline, that is to say a set of sections, each section being represented by a polynomial. He also deduces the thickness of the tire P at each point of the profile. After this acquisition step, the controller controls a shredding step. The shutters 140 are closed again. The rotating heads 15 are placed about 5 mm from the interpolated profile, with the axis of rotation T substantially perpendicular to the interpolated curve. The tire P is rotated by the mandrel 12 at a speed which is a function of the thickness calculated previously. The greater the thickness, the slower the feedrate to ensure that the entire thickness is treated in one pass. The liquid pressure is supplied to the rotating heads 15 which send multiple ultra-high pressure jets against the surface of the tire P, for example between 2000 and 4000 bar. The

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jets describe spirals on the surface of the tire P and cut fine particles of rubber and fabric that are discharged with the liquid and fall. The movable arms 131, 132, 16 move so that the rotating heads traverse the interpolated profile at a constant distance and always in a normal orientation to the profile. The metal carcass of tire P remains in place and is thus cleaned. When the entire surface of the tire P is treated, the movable arms 131, 132, 16 and the rollers are disengaged, the rotation of the rollers 122 is stopped and the mandrel 12 pivots a half turn to release the metal carcass tire P outside the enclosure 10. This is cleared and a new cycle can begin again.

Claims (13)

REVENDICATIONS1. A method of shredding used tires by using at least one rotating head (15) producing multiple ultra-high pressure jets to the surface (Se, Si) of a tire (P) to be shredded, and during a step of shredding, the rotating head (15) is moved relative to the surface of the tire (P), the method being characterized in that the rotating head (15) is moved along a defined path as a function of the measured tire geometry (P). ). 2. Method according to claim 1, wherein an acquisition step is performed before the shredding step, during which the external geometry (Se) of the tire (P) to be shredded is measured and a trajectory of the head is deduced therefrom. rotating (15) for the shredding operation. 3. Method according to claim 2, wherein a series of measuring points of the surface (Se, Si) of the tire (P) is acquired, and a profile function is calculated in the form of an interpolated curve between the points. . The method of claim 3, wherein the interpolated curve is a spline. 5. Method according to claim 3, wherein during the shredding operation, the rotating head (15) is oriented according to a normal to the interpolated curve. 6. The method of claim 2, wherein is further carried, during the acquisition step, a measurement of the inner geometry (Si) of the tire (P). 7. The method as claimed in claim 6, in which the local thickness of the tire (P) and the speed of advance for the shredding operation are deduced from the inner geometry (Si) and from the outer geometry (Se). . 11 A tire shredding apparatus having at least one rotating head (15) for producing multiple ultra high pressure jets to the surface of a tire (P) to be shredded, means for moving the head relative to the surface of the tire tire (P), characterized in that it further comprises measuring means (14) of the tire geometry (P) and means for determining a trajectory for the rotating head (15) defined according to the measured geometry. 9. shredding plant according to claim 8, wherein the measuring means comprise at least one movable arm (131, 132, 16) carrying a measurement cell (14) distance without contact. 10. Installation according to claim 8, wherein the movable arm (131, 132, 16) further supports one of the rotating heads (15). 11. Installation according to claim 10, characterized in that it comprises a mandrel (12) for mounting the tire (P) rotatable about its axis of symmetry (S), the movable arm (131, 132, 16) being fit to move in a radial plane containing the axis of rotation (S) of the tire (P). 12. Installation according to claim 10, characterized in that it comprises two outer movable arms (131, 132) for measuring and shredding the outer surface (Se) of the tire (P), and an inner movable arm (16) for measuring and shredding the inner surface (Si) of the tire (P). 13. Installation according to claim 10, wherein the rotating head (15) is pivotally mounted about a pivot axis (V) perpendicular to the radial plane.