TYRE DISPOSAL

Abstract: A method of disposing of used tyres comprising the operations of removing the rubber component of used tyres from the associated casing, granulating the rubber, enclosing the granulated rubber in impervious chemically inert containers adapted to fit together to provide a stable, close packed integrated mass, and stacking the containers to form the integrated mass.

Description: TYRE DISPOSAL The present invention relates to a method for the disposal of used pneumatic tyres. In 1996 it was estimated that some 36 million car and truck tyres in the United Kingdom alone would reach the end of their working fives. Similar figures apply to other countries also. It can be appreciated that the disposal of such a large number of tyres is a serious problem, which has exercised the authorities for some time and which will increase in sympathy with the increase in motor vehicle use. At present, approximately a quarter of all used tyres are disposed of legally into landfill or are stockpiled, or are illegally dumped. Tyres disposed in landfill are supposedly cut into quarters so that when they are tipped into a landfill site they will interlock, at least to some extent, so reducing the space required to receive a given number of tyres. However, not only is the interlocking of the quartered tyres uncontrolled and therefore not perfect, but there are many air spaces in the mass of tyres which provide paths for both the passage of water and air through a mass of tyres. The former facilitates the possible leaching of contaminants from the tyres into aquifers and water courses and the latter the burning of the mass of tyres, should a fire be started in the mass of tyres, either accidentally, or not. Such fires can be a major problem as not only do they produce heavy smoke, but they can be very difficult to put out. One, at least, has been burning for many years. It is an object of the present invention to provide an improved method of preparing used tyres for disposal in landfill or by stockpiling. According to the invention there is provided a method of disposing of used tyres comprising the operations of removing the rubber component of used tyres from the associated casing, granulating the rubber, enclosing the granulated rubber in impervious chemically inert containers adapted to fit together to provide a stable, close packed integrated mass, and stacking the containers to form the integrated mass. Preferably there is included the operation of separating the edge beads of the tyres from the remainder of the tyre casings. Examples of suitable shapes for the containers are cubes or right prisms of square, hexagonal, or rectangular cross-section. Preferably the containers are adapted to provide channels therebetween when stacked and there is included the operation of filling the channels with an inert material. Not only does the inert material in the said channels help to stabilise the stacked containers, but it increases the fire resistance of the stacked containers as the passage of oxygen between the inevitable gaps between the containers is hindered. Preferably the containers have protruding ribs which are so positioned as to interlock and are in two sections, a main body portion and a sealable closure member, the main body portion of each container having a deformable zone at the top of the main body portion of the container. This has two advantages. Firstly, the weight of a second filled container upon a first filled container causes the upper region of the first container to deform until the weight of the second container is carried by the compression of the rubber in the first container, so preventing the formation of air space due to the settlement of the rubber granules in the first container and increasing the fire resistance of the stacked containers. Also, if the main body portion of each container has a recess formed around its lower periphery into which the deformable zone of a lower container can deform, then the mechanical stability of the stacked containers is improved. Suitable materials for the containers are ignition resistant, high impact, inert polystyrene and ignition resistant forms of the plastics known as A.B.S. According to the invention in a second aspect, there is provided a plant for the disposal of used tyres, comprising a receiving and sorting station for used tyres, an apparatus for removing the rubber element of the tyres from their associated casings, means for reducing the rubber to granules of approximately the same size and filling impervious chemically inert containers with the granulated rubber, the said containers being adapted to fit together to provide a stable, close-packed integrated mass and mans for sealing the filled containers. Preferably there is included means for removing the edge beads of the tyres from the remainder of the tyre casings. The invention will now be described, by way of example, with reference to the accompanying drawings, in which: - Figure 1 is a flow diagram of a process embodying the invention for disposing of discarded motor vehicle tyres, and also illustrates schematically a plant embodying the invention for disposing of used tyres. Figure 2 (a) is a schematic view of a container for granulated rubber from motor vehicle tyres for use in a process as described with reference to Figure 1. Figure 2 (b) shows how a portion of a container such as that described with reference to Figure 2 (a) can be modified to provide a lifting point. Figure 3 is a section in plan of a portion of a stack of containers such as described with reference to Figure 2 (a) or 2 (b). Figure 4 is a schematic view of a second form of container for use in a process as described with reference to Figure 1, and Figure 5 is schematic view of a third form of container for use in a process as described with reference to Figure 1. The stages of a process and the stations of a plant according to the invention for preparing tyres for disposal , as shown in Figure 1 are as follows :- 1. Removing the wires from the seating beads at the edges of the tyres and recovering the bead wires as scrap metal. 2. Removing the rubber from the remainder of the tyres. 3. Granulating the rubber to produce particles of approximately the same size. 4. Encasing the rubber in a sealed non-biodegradable container. Stage 4 of the process preferably includes the operation of vibrating the containers as they are filled so as to increase the packing density of the granules. There may be included also the operation of extracting residual air from the filled and closed containers prior to their final sealing. A suitable container for use in stage 4 of the process described above is shown in Figure 2. Referring to Figure 2 (a) and Figure 2 (b) a container 200 for use in the disposal of used motor vehicle tyres by a method such as that described above consists of an upper portion 201 and lower portion 202. The combined container 200 has a generally cubic shape, but each vertical face, as shown in Figure 2, is provided with two parallel longitudinal projections, 203 and a taper of some two degrees is provided to facilitate stacking. The projections 203 act as strengthening ribs and are so arranged that when the containers 200 are filled and stacked together, the projections 203 interlock as shown in Figure 3 to provide an integrated mass in which there is a pluraHty of vertical channels, designated 301 in Figure 3, which can be filled with an inert material. The upper surface 204 of the upper portion 201 of the container 200 is provided with two indentations 205. The bottom of the lower portion 202 of the container 200 is provided with similar protrusions, not shown in Figure 2. to provide vertical stability when filled containers are stacked upon one another. An upper region 206 of the sides 207 of the lower portion 202 of the container 200 is made to be weaker than the remainder of the sides 207 of the lower portion 202 of the container 200 so as to provide a crumple zone 208 so as to enable the weight of one filled container 200 to compact the granulated rubber in a lower container. The weakening can be achieved by, for example, providing corrugations around the upper region of the lower portion 202 of the container 200. The same effect can be provided by making the sides 209 of the upper portion 201 of the container weaker than the sides 207 of the lower portion 202 of the container 200. In order to facilitate the joining together of the upper and lower portions 201, 202, respectively, of the container 200, the upper edge of the lower portion 202 of the container 200 can be reheved to provide a ledge upon which the upper portion 201 of the container 200 can sit. Figure 2 (b) shows how the projections 203 on two opposed sides of the lower portion 202 of the container 200 can be shaped to provide lifting lugs 210. If one of the projections 203 is on the centre fine of its side of the lower portion 202 of the container 200, then only that projection needs to be shaped so as to provide a lifting lug. In use, the lower portion 201 of the containers 200 are filled to the brim with granulated rubber removed from old motor vehicle tyres, the upper portion 201 of the container is placed in position and the junction between them is sealed. If so desired, residual air can be extracted from the filled containers prior to the final sealing of the containers. The containers 200 are then stacked together in layers as shown in Figure 3 to form an integrated mass as described above. As each layer of containers 200 is completed an inert material such as earth or sand is poured into the channels 301 formed between the containers 200 if desired. This filling of the channels 301 between the containers 200 decreases the fire risk. When one layer of containers 200 is completed, another layer is placed upon it, the gaps 301 again filled, and so on. As each succeeding container 200 is placed on top of the preceding one, its weight causes the crumple zone of the preceding container 200 to deform to compact the granulated rubber and reduce the air space within it, again reducing the fire hazard. As described, initial vertical integration between the layers of containers 200 in the stack is provided by the indentations 205 in the tops of the sealed containers and the protrusions in the bottom thereof. An alternative way of achieving this is relieve the periphery of the bottom of each lower portion 202 of the container in the stack so that when the crumple zones 208 of the containers 200 in the stack, they deform into the reliefs around the bottoms of the lower portions 201 of the container 200. Preferably, the stack of containers 200 is built upon a prepared area of a land-fill site which is then back-filled. Again, this reduces the fire hazard. However, if so desired, the stack of containers can be built above ground. Figure 4 is a schematic view of a second form of container, which generally is similar to the container described above, but the interlocking projections are disposed differently. The upper portion of the container also is somewhat different in that it is provided with a single locating depression 401 into which the bottom portion of a superimposed container fits. Similar components have similar reference numerals. Figure 5 is a schematic view of a third form of container 500, which basically is the inverse of the two previous containers. The major portion 501 of the container 500 has a greater taper than those of the above described containers, and the closure portion 502 fits within the major portion 502 of the container and moves therein to provide a crumple zone. Again, although none is shown, longitudinal strengthening ribs can be provided. In use, the container 500 is filled, sealed and then inverted for stacking. All the above forms of container can be provided with recesses in the bottom face to receive the prongs of a fork lift truck to facilitate their movement and stacking. Suitable materials for the containers 200 are flame-resistant high impact polystyrene or the plastics material known as A.B.S. A further advantage of the present invention is that should a need for the rubber be found, it is a relatively simple matter to retrieve the rubber from the stack of containers 200.

Claims: CLAIMS A method of disposing of used tyres comprising the operations of removing the rubber component of used tyres from the associated casing, granulating the rubber, enclosing the granulated rubber in impervious chemically inert containers adapted to fit together to provide a stable, close paced integrated mass, and stacking the containers to form the integrated mass A method according to Claim 1 wherein there is included the operation agitating the containers as they are filled thereby to increase the packing density of the rubber granules in the containers A method according to Claim 1 or Claim 2 wherein there is included the operation of extracting residual air from filled containers prior to sealing them finally A method according to any of Claims 1 to 3 wherein there is included the operation of separating the edge beads of the tyres from the remainder of the tyre casings A method according to any of Claims 1 to 4 wherein the containers are adapted when stacked to provide continuous channels therebetween and there is included the operation of filling the channels between stacked containers with an inert non-combustible material A plant for the disposal of used tyres, comprising a receiving and sorting station for used tyres, means for removing the rubber element of the tyres from their associated casings, means for reducing the rubber to granules of approximately the same size and filling impervious chemically inert containers with the granulated rubber, the said containers being adapted to fit together to provide a stable close-packed integrated mass, and means for sealing the filled containers A plant according to Claim 6 wherein there is included means for removing the edge beads of the tyres from their associated casings A plant according to Claim 6 or Claim 7 wherein there is included means for agitating the containers as they are filled A plant according to any of Claims 6 to 9 wherein there is included means for extracting residual air from filled and closed containers A container for use in a method according to any of Claims 1 to 5 or a plant according to any of the Claims 6 to 9 wherein the containers comprise a main body portion and a closure portion the cross-sections of which are generally square, rectangular, hexagonal or octagonal so as to form a close-packed assembly when stacked A container according to Claim 10 wherein at least the containers are adapted to provide continuous channels there between when stacked A container according to Claim 1 1 wherein at least the ma body portion of the container is provided with a plurality of longitudinal projections adapted to interact with those of the main body portions of adjacent containers to interlock the containers and provide the said channels therebetween A container according to any of Claims 10 to 12 wherein the closure member of one container is adapted to engage with the bottom of a superimposed container in a stack of containers A container according to any of Claims 10 to 13 wherein there is included a longitudinally collapsible zone adapted to facilitate the vertical integration of stacked containers A container according to Claim 14 wherein the longitudinally collapsible zone is provided by a region of the vertical walls of one or other portions of the containers which is less rigid than the remainder A container according to Claim 15 wherein the lower periphery of the main body portion of one container has a recess into which the collapsible zone of a lower container in a stack can deform thereby to facilitate the fonnation of a vertically integrated mass of stacked containers 17. A container according to Claim 14 wherein the closure member is adapted to move longitudinally with the main body portion of the container thereby to provide the said collapsible zone. 18. A method of disposing of used tyres substantially as hereinbefore described and with reference to Figure 1 or Figures 2 to 5 of the accompanying drawings. 19. A plant for the disposal of used tyres substantially as hereinbefore described and with reference to Figure 1 or Figures 2 to 5 of the accompanying drawings. 20. A container for use in the disposal of used tyres substantially as hereinbefore described and with reference to the accompanying drawings.

Inventors: KEOGH HUGH MICHAEL, KEOGH, HUGH, MICHAEL
Applicants: KEOGH HUGH MICHAEL, KEOGH, HUGH, MICHAEL
Application year: 2000
Main classification: B29B17
IPC codes: B09B1, B09B3, B29B17, B65D21, B65D25, B65D85