APPARATUS AND METHOD FOR DE-VULCANISATION OF RUBBER
20220315725 · 2022-10-06
Inventors
Cpc classification
B29B17/02
PERFORMING OPERATIONS; TRANSPORTING
Y02W30/62
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B29B2017/0286
PERFORMING OPERATIONS; TRANSPORTING
C08J2319/00
CHEMISTRY; METALLURGY
C08J11/10
CHEMISTRY; METALLURGY
C08J2321/00
CHEMISTRY; METALLURGY
B29B2017/0484
PERFORMING OPERATIONS; TRANSPORTING
B29B2017/0203
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
The invention provides an apparatus for de-vulcanisation of rubber from a rubber component, preferably a rubber tire. The apparatus comprises a cleaning device configured to clean and/or sanitize the rubber and a mixing device having at least one rotor configured to de-vulcanise the cleaned and/or sanitized rubber.
Claims
1. An apparatus for de-vulcanisation of rubber from a rubber component, the apparatus comprising: a cleaning device configured to clean or sanitize the rubber; and a mixing device having at least one rotor configured to de-vulcanise the cleaned or sanitized rubber.
2. The apparatus of claim 1, wherein the cleaning device is configured to clean or sanitize the rubber by applying heat or applying pressure to the rubber.
3. The apparatus of claim 1, wherein the at least one rotor has at least one blade which is configured to apply mechanical stress to the cleaned or sanitized rubber to de-vulcanise the cleaned or sanitized rubber.
4. The apparatus of claim 3, wherein the at lease one blade is configured to apply the mechanical stress to the cleaned or sanitized rubber in a substantially tangential direction.
5. The apparatus of claim 1, wherein the mixing device is further configured to add at least one chemical additive to the cleaned or sanitized rubber, and wherein the at least one chemical additive is suitable to break cross-links of the cleaned or sanitized rubber.
6. The apparatus of claim 5, wherein the at least one chemical additive is a de-vulcanisation agent representing between 1% and 15% of the weight of the cleaned or sanitized rubber.
7. The apparatus of claim 1, wherein the cleaning device is an autoclave.
8. The apparatus of claim 1 in a combination with an apparatus for removing rubber from the rubber component; and an apparatus for reworking of non-vulcanised rubber or de-vulcanised rubber configured to produce recycled rubber comprising the non-vulcanised rubber or the de-vulcanised rubber.
9. A method for de-vulcanisation of rubber from a rubber component, the method comprising: cleaning or sanitizing the rubber by using a cleaning device; and de-vulcanising the cleaned or sanitized rubber by using a mixing device having al least one rotor.
10. The method of claim 9, wherein the step of cleaning or sanitizing the rubber comprises application of heat or application of pressure to the rubber.
11. The method of claim 9, wherein the step of de-vulcanising comprises applying mechanical stress to the cleaned or sanitized rubber.
12. The method of claim 11, wherein the mechanical stress is applied to the rubber in a substantially tangential direction.
13. The method of claim 9, wherein the step of de-vulcanising comprises adding at least one chemical additive to the cleaned or sanitized rubber to break the cross-links of the cleaned or sanitized rubber, wherein the least one chemical additive is a de-vulcanisation agent, and representing between 1% and 15% of the weight of the cleaned or sanitized rubber and suitable to aid breaking cross-links of the cleaned or sanitized rubber.
14. The method of claim 9 further comprising: prior to de-vulcanising, removing the rubber from the rubber component; and subsequent to the de-vulcanising, reworking the rubber to produce recycled rubber.
15. The apparatus of claim 1, wherein the rubber component is a rubber tire.
16. The apparatus of claim 6, wherein the at least one chemical additive is a de-vulcanisation agent representing 5% of the weight of the cleaned or sanitized rubber.
17. The method of claim 13, wherein the at least one chemical additive is a de-vulcanisation agent representing 5% of the weight of the cleaned or sanitized rubber.
18. The method of claim 9, wherein the rubber component is a rubber tire.
19. The method of claim 2, wherein the heat applied to the rubber is in a range between 100 and 120 degree Celsius.
20. The method of claim 10, wherein the heat applied to the rubber is in a range between 100 and 120 degree Celsius.
Description
BRIEF DESCRIPTION OF THE FIGURES
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[0093] In general, the reworking apparatus 400 can be fed with de-vulcanised rubber, which has been de-vulcanised by the apparatus 300 for de-vulcanisation, or with rubber that has not been vulcanized before and thus not been de-vulcanised by the apparatus 300 for de-vulcanisation.
[0094] The above mentioned apparatus 200, 300, 400 of the system 1 are next described separately in more detail. However, the below description of the individual apparatus 200, 300, 400 apply to the apparatus 200, 300, 400 in the system 1 for recycling of non-vulcanised rubber or de-vulcanised rubber of a rubber component.
[0095] The methods described herein may also be combined in the same manner as the apparatus. That is, the methods relating to removing, de-vulcanisation, and reworking may be combined to one method, wherein the de-vulcanisation method is optional, because it is only needed for recycling of vulcanized rubber.
[0096] Removing Apparatus
[0097] As shown in
[0098] The sensor 210 comprises a transmitter 211 disposed on one side of the rubber component 8 and configured to emit the electromagnetic signal 20 towards the rubber component 8, and a receiver 212 disposed at another side of the rubber component 8 and configured to receive the electromagnetic signal 21 refracted at the rubber component 8.
[0099] Alternatively, the sensor 210 comprises a transmitter 211 disposed on one side of the rubber component 8 and configured to emit the electromagnetic signal 20 towards the rubber component 8, and a receiver (not shown) disposed at the same side as the transmitter 211 of the rubber component 8 and configured to receive the electromagnetic signal 21 reflected at the rubber component 8.
[0100] The terahertz frequency is between 0.3 and 30 THz, preferably between 0.3 and 10 THz, more preferably between 0.3 and 6 THz and most preferably between 0.3 and 3 THz.
[0101] The remover device 220 is configured to remove the rubber until a residual thickness of the outer rubber layer of 1 mm, preferably 600 μm, more preferably 300 μm.
[0102] The sensor 210 is configured to evaluate refraction or reflection peaks in the received electromagnetic signal by performing a time-domain analysis to determine the thickness of the outer rubber layer on top of the textile components. Also, the sensor 210 is configured to continuously determine the thickness of the outer rubber layer on top of the textile components during removing and to cause the remover device 220 to stop removing if the determined thickness of the outer rubber layer is below a predetermined threshold.
[0103] The predetermined threshold is 1 mm, preferably 600 μm, more preferably 300 μm.
[0104] Furthermore, the remover device 220 comprises a rotor 221 having at least one blade 222 and one support hub 223. The at least one blade 222 is detachably mounted on the support hub 223. The least one blade 222 may be a stainless steel disk with a plurality of cutting teeth along an outer circumferential surface thereof.
[0105] The at least one stainless steel disk is configured to be removably clamped onto the support hub 223, preferably by conical inserts.
[0106] The at least one blade is provided in plurality of two, three, four, five or more. The distance between the blades is between 21 and 2 mm, preferably between 18 and 4 mm, more preferably between 10 and 4 mm, and most preferably about 6 mm. The number of blades is between 2 to 25, preferably 5 to 20, more preferably 5-15, even more preferably 5-10 and most preferably 10.
[0107] The apparatus 200 of the present invention preferably further comprises a positioning system 230 configured to position the rotor 221 with respect to the outer cirumferencial surface of the rubber component, based on the determined thickness of the outer rubber layer on top of the textile components.
[0108]
[0109] In general, a characteristic of the waves in the THz frequency band is their interaction with the structure and composition of materials. Using this characteristic, it is then possible to obtain information about the internal structure of a sheet of material by analyzing the behavior of the electromagnetic beam when it crosses that sheet.
[0110] According to certain embodiments of the present invention it is preferred to precisely measure the overall thickness and the relative position of the internal textile cords 9 within the rubber component 8.
[0111] In
[0112] The measurement system (sensor 210) is based on the properties of electromagnetic waves that, when passing through a sheet of material, may be partially refracted (a variation in the reflection index is detected).
[0113] For example, a transmitter antenna sends a sequence of electromagnetic pulses that are focused as a beam on the surface of the sample to be measured through a set of lenses.
[0114] Considering the multilayer structure of rubberized fabric as illustrated in
[0115] Due to the various refractions, a receiver antenna captures pulses having covered different distances. Through a special time-domain analysis of the peaks of the signals, this information is used to estimate the thickness of materials.
[0116] The relationship between time (t), the thickness of the sample to be measured (D) and the reflection index (n) is expressed by the following formula, where v and c represent the speeds of the electromagnetic wave in the material and vacuum respectively:
[0117]
[0118] The method comprises the steps of S210 transmitting an electromagnetic signal with a terahertz frequency onto the rubber component, S220 receiving the electromagnetic signal refracted or reflected at the rubber component, S230 determining the thickness of the outer rubber layer on top of the textile components based on the received electromagnetic signal, and S240 removing the rubber from the rubber component based on the determined thickness of the outer rubber layer on top of the textile components.
[0119] De-Vulcanisation Apparatus
[0120] According to another aspect, the present invention provides an apparatus 300 for de-vulcanisation of rubber from a rubber component 8. The rubber component 8 can be e.g. used rubber tires and/or rubber production waste. As schematically shown in
[0121] According to this embodiment the cleaning device is an autoclave. The cleaning device 310 is configured to clean and/or sanitize the rubber by applying heat and/or pressure to the rubber. The heat can be in a temperature range between 80 and 180 degree Celsius. Preferably the heat is in a range of 100 to 120 degree Celsius.
[0122] The pressure can be in a range between atmospheric pressure and 5.0 bar. Preferably the pressure is in a range between atmospheric pressure and 2.7 bar.
[0123] The at least one rotor 321 of the mixing device 320 has at least one blade which is configured to apply mechanical stress to the cleaned and/or sanitized rubber to de-vulcanise the cleaned and/or sanitized rubber. The blade is configured to apply the mechanical stress to the cleaned and/or sanitized rubber in a substantially tangential direction. The at least one rotor 321 has four blades. Preferably, two of the four blades are configured to apply the mechanical stress to the rubber, while the two other blades of the rotor 321 are smaller and configured to support mixing of materials/substances.
[0124] With reference to
[0125] Each of the rotors 321 comprises two long blades 322a, 322c and two short blades 322b, 322d (in general referred to as 322), where only one long blade and one short blade 322 on each rotor 321 is visible in
[0126] The mechanical (tangential) stress is applied by the rotors 321 that are counter-rotating. In particular, the tangential stresses (shear stress) are applied by the four blades 322 (two big and two small) on each rotor 321, therefore the area of major effectiveness of the action on the rubber is in the centre between the two axis' of the rotors 321.
[0127] In addition, the tangential stresses that occurs to the rubber between the rotor blades 322 and the chamber itself may also be be used for the de-vulcanisation process. In particular, the walls 323, 324 of the apparatus 300 may also create tangential stress (shear stress) in combination with the rotating blades 322.
[0128] In a preferred embodiment, baseline data of the apparatus 300 may be set as follows: electric motor maximum torque: 177 Nm; gearbox reduction ratio: i=26.97; and maximum transmittable torque: 4774 Nm.
[0129] During de-vulcanisation, the rotors 322 may receive a maximum torque of 2000-2250 Nm.
[0130] The energy absorption may vary with relation to compound mixes.
[0131] Another baseline data of the apparatus 300 that may be relevant to delineate the performance parameters of the set-up, is the “power density” of the mixer (mixing device 320): the electric motor may have a rated power of 25 kW; and the reaction chamber may have a nominal capacity of 3.6 litres. In this regard, it is noted that the nominal capacity may differ from the capacity ultimately usable, that is e.g. 2.5 litres. Therefore, the power density available may be 10 kW/litre.
[0132] Applying the same parameterisation for the energy absorption range, as considered above for the torque, the resulting values may be 4.2-4.7 kW/litre.
[0133] Beyond that, the mixing device 320 is further configured to add at least one chemical additive to the cleaned and/or sanitized rubber which aids breaking the cross-links of the cleaned and/or sanitized rubber. Preferably, the at least one chemical additive is a de-vulcanisation agent. The de-vulcanisation agent represents between 1% and 15% of the weight of the cleaned and/or sanitized rubber and is suitable to aid breaking cross-links of the cleaned and/or sanitized rubber. Preferably the de-vulcanisation agent represents 5% of the weight of the cleaned and/or sanitized rubber. Preferably, the two smaller blades of the rotor 321 enable a homogeneous mixing of the chemical additive and the rubber.
[0134]
[0135] Reworking Apparatus
[0136]
[0137] The gear pump 410 comprises at least one mesh or grid at its output which is configured to filter inhomogenities, e.g. scortches, dirt, impurities, grains etc. The mixer-extruder 420 comprises a mixer 421. The mixer 421 is configured to add to the rubber at least one element of the group consisting of: additives, fillers, polymers, plasticizers or activators. Preferably, the mixer 421 is also configured to add to the rubber at least one accelerator and at least one crosslinker to produce recycled rubber. Preferably, the accelerator is at least one of CBS and ZBEC. Preferably, the crosslinker is sulphur 95%.
[0138] The mixer-extruder 420 preferably comprises an extruder head 422 configured to extrude the recycled rubber. The extruder head 422 is coupled to the output end of the mixer-extruder 420. The extruder head 422 may also be coupled directly to the mixer-extruder 420, such that no means for transportation, e.g. conveyors, or other output means, e.g. sheeting mills, are necessary.
[0139]
[0140] The step of homogenizing the rubber comprises the step of adding to the rubber at least one element of the group consisting of: additives, fillers, polymers, plasticizers and activators. Further, the step of homogenizing the rubber comprises the step of adding to the rubber at least one accelerator and at least one crosslinker. The accelerator preferably is at least one of CBS or ZBEC. The crosslinker is preferably sulphur 95%.
[0141] The system according to the present invention enables recycling of rubber, e.g. of rubber from used rubber components or rubber production waste. The recycled rubber is of high quality and has similar material properties as rubber produced from natural rubber.
[0142] This is achieved due to the process of removing the rubber with the aid of the apparatus for removing rubber, according to the present invention. In particular, only the rubber that covers the textile components of the rubber components is removed to be recycled. Therefore, the present application detects the position of the textile components via electromagnetic signals and stops the remover device, before the textile components are touched. Therefore, the removed material does not include textile or other non-rubber components, thereby avoiding inhomogeneities. With the apparatus for de-vulcanisation of rubber, according to the present invention, cleaned and sanitized rubber is produced as an intermediate product. This cleaned and sanitized rubber is de-vulcanised by the apparatus as of the present invention such that rubber which can be reprocessed is produced. Advantageously, this rubber does not contain non-rubber material, e.g. textile components.
[0143] The apparatus for reworking non-vulcanised rubber or de-vulcanied rubber enables to directly extrude recycled rubber, without the need of other extraction means. The recycled rubber is of high quality enabling a use in various contexts and fields.
[0144] The aforementioned features which may have been described solely with respect to the respective apparatus 200, 300, 400 apply to the respective methods as well. Their description in relation to the respective methods has simply be omitted to avoid any unnecessary repetitions.
[0145] As the present invention may be embodied in several forms without departing from the scope or essential characteristics thereof, it should be understood that the above-described embodiments are not limited by any of the details of the foregoing descriptions, unless otherwise specified, but rather should be construed broadly within the scope as defined in the appended claims, and therefore all changes and modifications that fall within the present invention are therefore intended to be embraced by the appended claims.
[0146] Furthermore, in the claims the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single unit may fulfil the functions of several features recited in the claims. The terms “essentially”, “about”, “approximately” and the like in connection with an attribute or a value particularly also define exactly the attribute or exactly the value, respectively. Any reference signs in the claims should not be construed as limiting the scope.
[0147] The present invention also relates to the following items: [0148] 1. Apparatus for removing rubber from a rubber component, preferably a rubber tire, wherein the rubber component comprises an outer rubber layer on top of textile components, the apparatus comprising: [0149] a sensor configured to transmit an electromagnetic signal with a terahertz frequency onto the rubber component, to receive an electromagnetic signal refracted or reflected at the rubber component, and to determine the thickness of the outer rubber layer on top of the textile components based on the received electromagnetic signal; and [0150] a remover device configured to remove the rubber from the outer rubber layer based on the determined thickness of the outer rubber layer on top of the textile components. [0151] 2. The apparatus of item 1, wherein the sensor comprises: [0152] a transmitter disposed on one side of the rubber component and configured to emit the electromagnetic signal towards the rubber component; and [0153] a receiver disposed at another side of the rubber component and configured to receive the electromagnetic signal refracted at the rubber component or a receiver disposed at the one side of the rubber component and configured to receive the electromagnetic signal reflected at the rubber component, [0154] wherein preferably the terahertz frequency is between 0.3 and 30 THz, preferably between 0.3 and 10 THz, more preferably between 0.3 and 6 THz and most preferably between 0.3 and 3 THz. [0155] 3. The apparatus of item 1 or 2, wherein the remover device is configured to remove the rubber until a residual thickness of the outer rubber layer of 1 mm, preferably 600 μm, more preferably 300 μm. [0156] 4. The apparatus of any one of items 1 to 3, wherein the sensor is configured to evaluate refraction or reflection peaks in the received electromagnetic signal by performing a time-domain analysis to determine the thickness of the outer rubber layer on top of the textile components and/or [0157] wherein the sensor is configured to continuously determine the thickness of the outer rubber layer on top of the textile components during removing and to cause the remover device to stop removing if the determined thickness of the outer rubber layer is below a predetermined threshold and [0158] wherein preferably the predetermined threshold is 1 mm, preferably 600 μm, more preferably 300 μm. [0159] 5. The apparatus of any one of items 1 to 4, wherein the remover device comprises a rotor having at least one blade and one support hub, wherein preferably the at least one blade is detachably mounted on the support hub and [0160] wherein preferably the at least one blade is a stainless steel disk with a plurality of cutting teeth along an outer circumferential surface thereof and [0161] wherein preferably the at least one stainless steel disk is configured to be removably clamped onto the support hub, preferably by conical inserts. [0162] 6. The apparatus of item 5, wherein the at least one blade is provided in plurality of two, three, four, five or more and/or the distance between the blades is between 21 and 2 mm, preferably between 18 and 4 mm, more preferably between 10 and 4 mm, and most preferably about 6 mm and [0163] wherein preferably the number of blades is between 2 to 25, preferably 5 to 20, more preferably 5-15, even more preferably 5-10 and most preferably 10. [0164] 7. The apparatus of item 5 or 6, further comprising a positioning system configured to position the rotor with respect to the outer cirumferencial surface of the rubber component, based on the determined thickness of the outer rubber layer on top of the textile components. [0165] 8. System for recycling of non-vulcanised rubber or de-vulcanised rubber of a rubber component, preferably a rubber tire, the system comprising: [0166] an apparatus for removing rubber from the rubber component according to any one of items 1 to 7; and [0167] an apparatus for reworking of non-vulcanised rubber or de-vulcanied rubber configured to produce recycled rubber. [0168] 9. The system of item 8, further comprising an apparatus for de-vulcanisation of the rubber. [0169] 10. A method for removing rubber from a rubber component, preferably a rubber tire, having textile components, wherein the rubber component comprises an outer rubber layer on top of textile components, the method comprising: [0170] transmitting an electromagnetic signal with a terahertz frequency onto the rubber component; [0171] receiving the electromagnetic signal refracted or reflected at the rubber component; [0172] determining the thickness of the outer rubber layer on top of the textile components based on the received electromagnetic signal; and [0173] removing the rubber from the rubber component based on the determined thickness of the outer rubber layer on top of the textile components. [0174] 11. The method of item 10, wherein the terahertz frequency is between 0.3 and 30 THz, preferably between 0.3 and 10 THz, more preferably between 0.3 and 6 THz and most preferably between 0.3 and 3 THz and/or wherein removing the rubber comprises removing the rubber until a residual thickness of the outer rubber layer of 1 mm, preferably 600 μm, more preferably 300 μm is reached. [0175] 12. The method of item 10 or 11, wherein determining the thickness of the outer rubber layer on top of the textile components comprises evaluating refraction or reflection peaks in the received electromagnetic signal by performing a time-domain analysis. [0176] 13. The method of any one of items 10 to 12, wherein determining the thickness of the outer rubber layer on top of the textile components comprises continuously determining the thickness of the outer rubber layer on top of the textile components during removing and stopping the removing if the determined thickness of the outer rubber layer is below a predetermined threshold and [0177] wherein preferably the predetermined threshold is 1 mm, preferably 600 μm, more preferably 300 μm and/or [0178] wherein removing the rubber from the rubber component comprises removing only the rubber from the rubber component. [0179] 14. A method for recycling of non-vulcanised or de-vulcanised rubber from a rubber component, preferably a rubber tire, the method comprising: [0180] a method for removing rubber according to any one of items 10 to 13; and [0181] a method for reworking the rubber to produce recycled rubber. [0182] 15. The method of item 14, further comprising a method for de-vulcanisation of rubber. [0183] 16. Apparatus for reworking of non-vulcanised rubber or de-vulcanied rubber from a rubber component, preferably a rubber tire, to produce recycled rubber, the apparatus comprising: [0184] a gear pump configured to receive and filter the rubber to produce filtered rubber; and [0185] a mixer-extruder configured to homogenize and extrude the filtered rubber to produce recycled rubber. [0186] 17. The apparatus of item 16, wherein the gear pump comprises at least one mesh or grid at its output which is configured to filter inhomogenities. [0187] 18. The apparatus of item 16 or 17, wherein the mixer-extruder comprises a mixer. [0188] 19. The apparatus of item 18, wherein the mixer is configured to: [0189] add to the rubber at least one element of the group consisting of: additives, fillers, polymers, plasticizers or activators; and [0190] add to the rubber at least one accelerator and at least one crosslinker to produce recycled rubber. [0191] 20. The apparatus of item 19, wherein the accelerator is at least one of CBS and ZBEC, and the crosslinker is sulphur 95%. [0192] 21. The apparatus of any one of items 16 to 20, wherein the mixer-extruder comprises an extruder head configured to extrude the recycled rubber. [0193] 22. The apparatus of item 21, wherein the extruder head is coupled to an output end of the mixer-extruder. [0194] 23. System for recycling of non-vulcanised rubber or de-vulcanised rubber from a rubber component, preferably a rubber tire, the system comprising: [0195] an apparatus for removing rubber from the rubber component; and [0196] an apparatus for reworking of non-vulcanised rubber or de-vulcanied rubber configured to produce recycled rubber according to any one of items 16 to 22. [0197] 24. The system of item 23, further comprising an apparatus for de-vulcanisation of rubber configured to de-vulcanise the rubber, preferably the removed rubber. [0198] 25. A method for reworking non-vulcanised rubber or de-vulcanised rubber from a rubber component, preferably a rubber tire, to produce and extrude recycled rubber, the method comprising: [0199] filtering the rubber; [0200] homogenizing the filtered rubber to produce recycled rubber; and [0201] extruding the recycled rubber. [0202] 26. The method of item 25, wherein homogenizing the rubber comprises the steps of: [0203] adding to the rubber at least one element of the group consisting of: additives, fillers, polymers, plasticizers and activators; and [0204] adding to the rubber at least one accelerator and at least one crosslinker. [0205] 27. The method of item 26, wherein the accelerator is at least one of CBS and ZBEC; and the crosslinker is sulphur 95%. [0206] 28. A method for recycling of non-vulcanised rubber or de-vulcanised rubber from a rubber component, preferably a rubber tire, the method comprising: [0207] a method of removing rubber from a rubber component; and [0208] a method for reworking the rubber to produce recycled rubber according to any one of items 25 to 27. [0209] 29. The method of item 28, further comprising a method for de-vulcanisation of rubber, preferably the removed rubber, to produce de-vulcanised rubber.