Method for managing a shutdown of an extrusion machine

Abstract

The invention relates to a method for managing a stoppage of an extrusion machine used to extrude an elastomer mixture whose composition includes at least one vulcanizing agent, the extrusion machine delivering the elastomer mixture in the form of a profiled product, the extrusion machine comprising a body and an extrusion member driven in motion inside this body, the body comprising at least one inlet through which the elastomer mixture is introduced, the body comprising an outlet equipped with a tool for shaping the elastomer mixture, the movement of the extrusion member inside said body driving the elastomer mixture towards the outlet of said body.When the extrusion machine stops, resulting in the extrusion die ceasing to move, and while a non-zero amount of elastomer mixture remains inside the machine, the management process provides for cooling at least a portion of the non-zero amount of elastomer mixture still present inside the machine. Figure in the abstract: none.

Description

Title of the invention: Method for managing a shutdown of an extrusion machine

[0001] The present invention relates to the management of shutdowns of an extrusion machine used to extrude an elastomer mixture whose composition includes a vulcanizing agent.

[0002] For example, in the tire manufacturing industry, various extrusion machines are used to produce different finished or semi-finished products useful for making tire blanks. These tire blanks include all the components of the future tire before curing. A majority of these finished or semi-finished products take the form of strips, bands, or sheets made from an elastomeric compound whose composition includes a vulcanizing agent, an elastomeric compound being a compound that includes at least one elastomer.

[0003] Due to the presence of a vulcanizing agent in an elastomeric compound and the temperature rise of this compound during extrusion, the vulcanization reaction may begin inside the extruder. When this reaction is only partially initiated, the compound inside the extruder is extracted and discarded because it no longer meets the required qualities for manufacturing a tire blank. For example, the compound will contain aggregates, also known as scouring. When this vulcanization reaction is more extensive, the compound may require the extruder to be stopped and disassembled for removal. In some cases, the accidental vulcanization of an elastomer mixture inside an extruder can damage extruder components, such as the mixture movement mechanism inside the extruder body.

[0004] Also, elastomeric mixtures whose composition includes a vulcanizing agent and which are intended to be extruded may contain one or more products intended to delay the initiation of a vulcanization reaction inside an extruder.

[0005] However, when it is envisaged to extrude an elastomer mixture whose composition includes a vulcanizing agent and one or more products intended to delay the vulcanization reaction, it remains necessary to control the flow rate of the extruder and the time spent by the elastomer mixture inside the extruder to avoid the appearance of soot and the disposal of part of the elastomer mixture.

[0006] Document FR2966373 proposes a method for regulating an extruder that determines, based on the characteristics and composition of the elastomer mixture, the maximum extruder flow rate required to prevent the formation of spatter. The method described in document FR2966373 also determines the maximum usable flow rate when restarting after a brief extruder shutdown.

[0007] According to a first drawback, the control method described in document FR2966373 does not allow for the management of long extruder shutdowns, for example, exceeding several seconds. In particular, the control method described in document FR2966373 does not allow for the control of the evolution of the vulcanization reaction of the mixture inside the extruder body when the extruder is stopped.

[0008] The present invention aims to provide a solution for managing long shutdowns of an extrusion machine when this machine contains an elastomer mixture whose composition includes a vulcanizing agent.

[0009] To this end, the invention relates to a method for managing a stoppage of an extrusion machine used to extrude an elastomer mixture whose composition includes at least one vulcanizing agent, the extrusion machine delivering the elastomer mixture in the form of a profiled product, the extrusion machine comprising a body and an extrusion member driven in motion inside this body, the body comprising at least one inlet through which the elastomer mixture is introduced, the body comprising an outlet equipped with a tool for shaping the elastomer mixture, the movement of the extrusion member inside said body driving the elastomer mixture towards the outlet of said body.

[0010] According to the invention, when the extrusion machine stops, causing the movement of the extrusion element to stop, and while a non-zero quantity of elastomer mixture is still present inside the extrusion machine, the management process provides for cooling at least a part of the non-zero quantity of elastomer mixture that is still present inside the extrusion machine.

[0011] In more detail, during a stoppage of the extrusion machine which causes a stoppage of the movement of the extrusion element and while a non-zero quantity of elastomer mixture is still present inside the extrusion machine, the management process provides for lowering the temperature of at least one of these components of the extrusion machine: the body, the extrusion element, or the shaping tool.

[0012] For example, the body, the extrusion element and / or the shaping tool being components of the extrusion machine traversed by at least one regulating channel allowing the circulation of a heat transfer fluid, during a stoppage of the extrusion machine resulting in a stoppage of the movement of the extrusion element and while a non-zero amount of elastomer mixture is still present inside the extrusion machine, the management process provides that the temperature of the heat transfer fluid circulating in at least one of the control channels is lowered to a value lower than the temperature of the component of the extrusion machine which is traversed by this control channel.

[0013] The lower-temperature heat transfer fluid cools the extrusion machine component in which it is located, thereby cooling the elastomer mixture still inside the extrusion machine when it is stopped. By cooling the mixture still present inside the extrusion machine, the vulcanization reaction of the elastomer mixture inside the extrusion machine is slowed down.

[0014] Advantageously, but not necessarily, the management process according to the invention may also provide that: - the temperature of the heat transfer fluid circulating in at least one control channel is lowered as soon as the extrusion machine is stopped or when the duration of the extrusion machine stoppage exceeds a time interval estimated based on the temperature of the elastomer mixture at the time the extrusion machine is stopped and the vulcanization time of the elastomer mixture at that temperature, - during a stoppage of the extrusion machine, the temperature of the heat transfer fluid circulating in at least one control channel of the extrusion machine body is lowered to a value lower than the temperature of that body, - the body of the extrusion machine comprising different sections and at least one of these sections being traversed by a regulating channel allowing the circulation of a heat transfer fluid, when the extrusion machine is stopped, the temperature of the heat transfer fluid circulating in the regulating channel of at least one section is lowered to a value lower than the temperature of that section, - the heat transfer fluid circulating in at least one regulating channel has a temperature of no more than 70°C as long as the duration of the extrusion machine shutdown is less than a time interval estimated based on the temperature of the elastomer mixture at the time the extrusion machine shuts down and the vulcanization time of the elastomer mixture at that temperature, for example, less than 75% of the vulcanization time of the elastomer mixture present in the extrusion machine, - when the duration of the extrusion machine shutdown is less than a time interval estimated based on the temperature of the elastomer mixture at the time the extrusion machine shuts down and the vulcanization time of the elastomer mixture at that temperature, for example, less than 75% of the vulcanization time of the elastomer mixture present in the extrusion machine, the temperature of at least one The temperature of a component of the extrusion machine is lowered to a value between 50°C and 70°C through the circulation of a heat transfer fluid within this component. - A heat transfer fluid with a temperature of no more than 50°C circulates in at least one control channel when a shutdown of the extrusion machine lasts longer than a time interval estimated based on the temperature of the elastomer mixture at the time the extrusion machine is stopped and the vulcanization time of the elastomer mixture at that temperature, for example, longer than the vulcanization time of the elastomer mixture present in the extrusion machine; - A heat transfer fluid with a temperature between 30°C and 50°C, and preferably between 35°C and 45°C, circulates in at least one control channel when a shutdown of the extrusion machine lasts longer than a time interval estimated based on the temperature of the elastomer mixture at the time the extrusion machine is stopped and the vulcanization time of the elastomer mixture at that temperature.for example, greater than the vulcanization time of the elastomer mixture present in the extrusion machine, - during a stoppage of the extrusion machine having a duration greater than a time interval estimated according to the temperature of the elastomer mixture at the time of the stoppage of the extrusion machine and the vulcanization time of the elastomer mixture at this temperature, for example greater than the vulcanization time of the elastomer mixture present in the extrusion machine, the temperature of at least one component of the extrusion machine is lowered to a value between 30°C and 50°C by means of the circulation of a heat transfer fluid in this component, - the vulcanizing agent is sulfur or a sulfur donor.

[0015] The invention also relates to a method of manufacturing a product from at least one profiled elastomer mixture product, this manufacturing method being implemented by a manufacturing machine fed by an extrusion machine whose stops are managed by a management method according to the invention.

[0016] In this manufacturing process, the product made by the manufacturing machine is, for example, a tire blank.

[0017] In this manufacturing process, the extrusion machine can, for example, continuously feed the manufacturing machine. Alternatively, the extrusion machine can, for example, sequentially feed the manufacturing machine. In both cases, the shutdowns of the extrusion machine can be managed using the management method according to the invention.

[0018] Other features and advantages of the invention will become apparent in the following description. This description, given by way of example and not limitation, refers to the accompanying drawings in which: - [Fig.1] schematically represents a first example of an extrusion machine whose stops can be managed using the management method according to the invention, - [Fig.2] schematically represents a second example of an extrusion machine whose stops can be managed using the management method according to the invention, - [Fig.3] illustrates in the form of a graph and various curves an example of managing a stop of an extrusion machine using the management method according to the invention.

[0019] The invention relates to a method for managing the shutdowns of an extrusion machine used to extrude an elastomer mixture whose composition includes at least one vulcanizing agent, an elastomer mixture being a mixture which includes at least one elastomer.

[0020] First example of an extrusion machine

[0021] Figure 1 schematically illustrates a first extrusion machine 10 whose stops can be managed using the method according to the invention. This extrusion machine 10 comprises a body 12 and an extrusion element 14 driven in motion within this body. The body 12 and the extrusion element 14 extend along a longitudinal axis AL. For example, the body 12 is cylindrical around the longitudinal axis AL and the extrusion element 14 is a screw with a helical thread. The extrusion element 14 is, for example, driven in rotation by a motor 16. Optionally, the extrusion machine 10 may comprise several extrusion elements, for example, two screws, housed within the body 12.

[0022] The body 12 includes at least one inlet 18 through which the elastomer mixture M is introduced. For example, this inlet 18 may be in the form of a hopper. For example, this inlet 18 may include a feeding device 20 for the elastomer mixture M. This feeding device 20 draws the elastomer mixture M into the body 12 and prevents the elastomer mixture M from exiting the body 12 when the extrusion member 14 is in motion. This feeding device 20 may, for example, be in the form of a tamping roller driven in rotation by a motor. Preferably, the motor 16 driving the rotating extrusion member is mounted on the body 12 near the inlet 18.

[0023] The body 12 also includes an outlet 22 equipped with a shaping tool 24 for the elastomer mixture M. The movement of the extrusion member 14 inside the body 12 drives the elastomer mixture towards the outlet 22 of said body. This shaping tool 24 extrudes the elastomer mixture M into a profiled product P, for example, with a constant cross-section. This shaping tool 24 takes, for example, the form of a profiling head through which at least one opening of variable cross-section passes along the longitudinal axis AL, and which progressively confers its profiled product shape to the exiting elastomer mixture M. of the extrusion machine. Alternatively, the shaping tool 24 can take the form of a four-sided blade mounted in a support block, a three-sided blade associated with a roller, or two rollers, at least one of which is a profiled roller.

[0024] Preferably, the inlet 18 of the body 12, the motor 16 and the feeding device 20 are located at a first end El of the extrusion machine 10, while the shaping tool 24 is located at the other end E2 of the extrusion machine.

[0025] In order to measure the temperature of the mixture inside the body 12 of the extrusion machine, a first temperature probe 26 can, for example, be installed in the body 12 of the extrusion machine. This first temperature probe 26 is installed so as to be in contact with the elastomer mixture M located in the body 12 of the extrusion machine. This first temperature probe 26 is connected to a control unit 28 of the extrusion machine so as to transmit to it a signal representative of the temperature of the elastomer mixture M located in the body 12 of the extrusion machine.

[0026] In order to measure the temperature of the elastomer mixture M as it passes through the shaping tool 24, a second temperature probe 30 can, for example, be installed in the shaping tool 24. This second temperature probe 30 is installed so as to be in contact with the elastomer mixture M located in the shaping tool 24. This second temperature probe 30 is also connected to the control unit 28 of the extrusion machine so as to transmit to it a signal representative of the temperature of the elastomer mixture located in the shaping tool 24.

[0027] The control unit 28 can also be connected to the motor 16 in order to control the movement of the extrusion member 14 in the body 12. Optionally, the control unit 28 can also be connected to the intake device 20 in order to control its operation.

[0028] To enable the implementation of the process according to the invention, the body 12, the extrusion element 14, the infeed device 20 and / or the shaping tool 24 are components of the extrusion machine, preferably traversed by at least one regulating channel R1, R2, R3, R4, R5, R6 allowing the circulation of a heat transfer fluid. Preferably, at least the body 12 is traversed by a regulating channel R3. Optionally, the body 12, the extrusion element 14, the infeed device 20 and / or the shaping tool 24 may be traversed by several regulating channels. These regulating channels R1, R2, R3, R4, R5, R6 are supplied with heat transfer fluid by one or more regulating units 32 allowing the heat transfer fluid to circulate in the regulating channel(s). Advantageously, a control unit 32 also allows control of the temperature of the heat transfer fluid circulating in the control channel(s) to which it is connected. For example, the operation of the control unit(s) 32 is controlled by the control unit 28. The control channel(s) R1, R2, R3, R4, R5, R6 allow, for example, the body 12, the extrusion element 14, the infeed device 20 and / or the shaping tool 24 to be brought to their ideal operating temperature for the start of an extrusion cycle. During an extrusion cycle, the control channel(s) R1, R2, R3, R4, R5, R6 maintain the components of the extrusion machine and the elastomer mixture M at the desired temperature.

[0029] Second example of an extrusion machine

[0030] Figure 2 schematically illustrates a second extrusion machine 110 whose stops can be managed using the method according to the invention. This second extrusion machine 110 comprises a body 112 and an extrusion element 114 driven in motion within this body. The body 112 and the extrusion element 114 extend along a longitudinal axis ALI. For example, the body 112 is cylindrical around the longitudinal axis ALI and the extrusion element 114 is a screw with a helical thread. The extrusion element 114 is, for example, driven in rotation by a motor 116. Optionally, the second extrusion machine 110 may comprise several extrusion elements 114, for example, two screws, housed within the body 112.

[0031] The body 112 includes at least one inlet 118 through which the elastomer mixture M is introduced. For example, this inlet 118 may be in the form of a hopper. For example, this inlet 118 may include a feeding device 120 for the elastomer mixture M. This feeding device 120 draws the elastomer mixture M into the body 112 and prevents the elastomer mixture M from exiting the body 112 when the extrusion member 114 is in motion. This feeding device 120 may, for example, be in the form of a tamping roller driven in rotation by a motor. Preferably, the motor 116 driving the rotating extrusion member is mounted on the body 112 near the inlet 118.

[0032] The body 112 of this second extrusion machine 110 differs from the body 12 of the first extrusion machine 10. In fact, the body 112 of this second extrusion machine 110 comprises different sections T1, T2, T3. These different sections T1, T2, T3, for example, facilitate the maintenance of the extrusion machine 110.

[0033] The body 112 also includes an outlet 122 equipped with a shaping tool 124 for the elastomer mixture M. The movement of the extrusion element 114 inside the body 112 drives the elastomer mixture towards the outlet 122 of said body. This shaping tool 124 allows the elastomer mixture M to be extruded into a profiled product P, for example, with a constant cross-section. This shaping tool 124 takes, for example, the form of a profiling head through which a variable section opening which allows the elastomer mixture M coming out of the extrusion machine to gradually give its profiled product shape.

[0034] Preferably, the inlet 118 of the body 112, the motor 116 and the feeding device 120 are located at a first end Eli of the extrusion machine 110, while the shaping tool 124 is located at the other end E12 of the extrusion machine.

[0035] In order to measure the temperature of the mixture inside the body 112 of the extrusion machine, first temperature probes 26-1, 26-2, 26-3 can, for example, be installed respectively in sections T1, T2, T3 of the body 112 of this second extrusion machine 110. These first temperature probes 26-1, 26-2, 26-3 are installed so as to be in contact with the elastomer mixture M located in the body 112 of the extrusion machine. These first temperature probes 26-1, 26-2, 26-3 are connected to a control unit 128 of the extrusion machine so as to transmit to it a signal representative of the temperature of the elastomer mixture M located in the body 112 of the extrusion machine.

[0036] In order to measure the temperature of the elastomer mixture M as it passes through the shaping tool 124, a second temperature probe 130 can, for example, be installed in the shaping tool 124. This second temperature probe 130 is installed so as to be in contact with the elastomer mixture M located in the shaping tool 124. This second temperature probe 130 is also connected to the control unit 128 of the extrusion machine 110 so as to transmit to it a signal representative of the temperature of the elastomer mixture located in the shaping tool 124.

[0037] The control unit 128 can also be connected to the motor 116 in order to control the movement of the extrusion member 114 in the body 112. Optionally, the control unit 128 can also be connected to the feeding device 120 in order to control its operation.

[0038] To enable the implementation of the process according to the invention, the sections T1, T2, T3 of the body 112, the extrusion member 114, the infeed device 120 and / or the shaping tool 124 are components of the extrusion machine, preferably traversed by at least one regulating channel R11, R12, R13, R14, R15, R16, R17, R18, R19, R20 allowing the circulation of a heat transfer fluid. Preferably, each section of the body 112 is traversed by at least one regulating channel. Optionally, the sections of the body 112, the extrusion member 114, the infeed device 120 and / or the shaping tool 124 may be traversed by several regulating channels. These regulating channels R11, R12, R13, R14, R15, R16, R17, R18, R19, R20 are supplied with heat transfer fluid by one or more regulating units 132, allowing the heat transfer fluid to circulate in the regulating channel(s). Advantageously, a The control unit 132 also allows for the control of the temperature of the heat transfer fluid circulating in the control channel(s) to which it is connected. For example, the operation of the control unit(s) 132 is controlled by the control unit 128. The control channel(s) R11, R12, R13, R14, R15, R16, R17, R18, R19, R20 allow, for example, bringing the body sections 112, the extrusion element 114, the infeed device 120 and / or the shaping tool 124 to their ideal operating temperature in preparation for starting an extrusion cycle. During an extrusion cycle, the regulation channel(s) R11, R12, R13, R14, R15, R16, R17, R18, R19, R20 maintain the components of the extrusion machine and the elastomer mixture M at the desired temperature.

[0039] Management method

[0040] As long as an extrusion machine 10,110 is in operation with parameters appropriate to the elastomer mixture M to be extruded and the elastomer mixture M continues to be extruded by the extrusion machine, the vulcanization reaction of the elastomer mixture M which may begin in certain areas located inside the extrusion machine is not significant enough to cause production hazards such as a blockage of the extrusion element 14 or a discard of the profiled product P.

[0041] However, during a stoppage of an extrusion machine 10,110 between two extrusion cycles or due to a production hazard originating from the extrusion machine or from a machine located upstream or downstream of it in the production chain, the vulcanization reaction of the elastomer mixture M which may initiate in certain areas located inside the extrusion machine may be significant enough to cause a blockage of the extrusion element 14,114 or a discard of the profiled product P generated by the extrusion machine.

[0042] The management method according to the invention makes it possible to slow down the evolution of the vulcanization reaction of the elastomer mixture M which is initiated in certain areas located inside the extrusion machine during a stoppage of the extrusion machine between two extrusion cycles or due to a production hazard.

[0043] In more detail, when the extrusion machine 10, 110 stops, resulting in the extrusion element 14, 114 ceasing to move, and while a non-zero quantity of elastomer mixture M is still present inside the extrusion machine, the management process provides for cooling at least a portion of the non-zero quantity of elastomer mixture M that is still present inside the extrusion machine. Preferably, the management process provides for cooling the elastomer mixture M that is still present in the hottest area(s) of the extrusion machine.

[0044] To this end, during a stoppage of the extrusion machine resulting in a stoppage of the movement of the extrusion member 14,114 and while a non-zero quantity of elastomer mixture M is still present inside the extrusion machine, the management process provides, for example, for lowering the temperature of at least one of these components of the extrusion machine: the body 12,112, the extrusion member 14,114, or the shaping tool 24,124. For example, the management process provides for lowering the temperature of the component(s), such as, for example, the extrusion member 14,114 and the shaping tool 24,124, in which the elastomer mixture M rises in temperature most rapidly during a stoppage of the extrusion machine.

[0045] Advantageously, the body 12,112, the extrusion element 14,114, and / or the shaping tool 24,124 are components of the extrusion machine preferably traversed by at least one regulating channel (RI,...,R20) allowing the circulation of a heat transfer fluid. Also, when the extrusion machine 10,110 stops, resulting in the extrusion element 14,114 stopping, and while a non-zero quantity of elastomer mixture M is still present inside the extrusion machine, the control method provides that the temperature of the heat transfer fluid circulating in at least one of the regulating channels (RI,...,R20) is lowered to a value lower than the temperature of the extrusion machine component traversed by that regulating channel.

[0046] Depending on the size of the extrusion machine, the quantity of elastomer mixture M present inside it and the composition of the elastomer mixture, and in particular the quantity of vulcanizing agent contained in this elastomer mixture, the temperature of the heat transfer fluid circulating in at least one control channel (RI,...,R20) is lowered as soon as the extrusion machine 10,110 is stopped or when the duration of the stop of the extrusion machine 10,110 is greater than a time interval estimated as a function of the temperature of the elastomer mixture at the time of the stop of the extrusion machine and the vulcanization time of the elastomer mixture at this temperature.

[0047] For example, the temperature of the heat transfer fluid circulating in at least one control channel (RI,...,R20) is lowered as soon as the extrusion machine 10,110 is stopped, or when the vulcanization reaction of the elastomer mixture is very rapid, or when the extrusion machine has a high extrusion flow rate.

[0048] The vulcanization time of an elastomeric mixture comprising a vulcanizing agent varies depending on the temperature of the elastomeric mixture. For a given temperature, this vulcanization time corresponds to the time required for the vulcanization reaction of the elastomeric mixture to be complete. For example, for an elastomeric mixture comprising a vulcanizing agent For vulcanization intended for tire manufacturing, the vulcanization time can range from a few minutes to several tens of minutes when this elastomer mixture is heated to temperatures between 100°C and 140°C. The following list gives real examples of vulcanization times for a given temperature of different elastomer mixtures with different compositions but all containing at least one vulcanizing agent: 15 min at 138°C, 6 min at 115°C, 4 min at 130°C, 3 min at 130°C, 5 min at 130°C.

[0049] For example, when the extrusion machine is stopped, the management process provides that the temperature of the heat transfer fluid circulating in at least one control channel R3,R4 of the body 12 of the extrusion machine 10 is lowered to a value lower than the temperature of this body 12. The temperature of the body 12 can be measured using the first temperature probe 26 if it is permanently present, or determined using a temperature probe temporarily placed on the body 12 during preliminary tests.

[0050] In the case where the body of the extrusion machine comprises different sections T1,T2,T3 and at least one of these sections is traversed by a control channel R13,R14,R15,R16,R17,R18 allowing the circulation of a heat transfer fluid, during a stop of the extrusion machine 110, the management process provides for example that the temperature of the heat transfer fluid circulating in the control channel R13,R14,R15,R16,R17,R18 of at least one section T1,T2,T3 is lowered to a value lower than the temperature of that section. The temperature of a section T1,T2,T3 of the body 112 can be measured using the first temperature probes 26-1,26-2,26-3 if these are permanently present, or determined using temperature probes temporarily placed on the body 112 during preliminary tests.

[0051] Depending on the size of the extrusion machine, the quantity of elastomer mixture M present inside it, and the composition of the elastomer mixture, and in particular the quantity of vulcanizing agent contained in this elastomer mixture, the control method may provide that the heat transfer fluid circulating in at least one control channel (RI,...,R20) has a temperature of no more than 70°C, and for example between 50°C and 70°C, as long as the duration of the extrusion machine shutdown is less than a time interval estimated based on the temperature of the elastomer mixture at the time the extrusion machine is stopped and the vulcanization time of the elastomer mixture at that temperature. For example, the control method may provide that the heat transfer fluid circulating in at least one control channel (RI,... .,R20) has a temperature at most equal to 70°C, and for example between 50°C and 70°C, as long as the duration of the machine shutdown. extrusion time is less than 75% of the vulcanization time of the elastomer mixture present in the extrusion machine.

[0052] When a stoppage of the extrusion machine has a duration greater than a time interval estimated according to the temperature of the elastomer mixture at the time of the stoppage of the extrusion machine and the vulcanization time of the elastomer mixture at this temperature, for example greater than the vulcanization time of the elastomer mixture present in the extrusion machine, the management process provides that a heat transfer fluid having a temperature not exceeding 50°C, for example between 30°C and 50°C, and preferably between 35°C and 45°C, circulates in at least one control channel (RI,...,R20).

[0053] Ideally, during a stoppage of the extrusion machine lasting longer than an estimated time interval based on the temperature of the elastomer mixture at the time of the extrusion machine stoppage and the vulcanization time of the elastomer mixture at that temperature, for example longer than the vulcanization time of the elastomer mixture present in the extrusion machine, the management process provides that the temperature of at least one component of the extrusion machine is lowered to a value between 30°C and 50°C by means of the circulation of a heat transfer fluid in that component.

[0054] For example, during a stoppage of the extrusion machine having a duration greater than a time interval estimated according to the temperature of the elastomer mixture at the time of the stoppage of the extrusion machine and the vulcanization time of the elastomer mixture at this temperature, for example greater than the vulcanization time of the elastomer mixture present in the extrusion machine, the management process provides that the temperature of the body 12 or of at least one section T1,T2,T3 of the body 112 is lowered to a value between 30°C and 50°C by means of the circulation of a heat transfer fluid in this body or this section(s).Preferably, during a shutdown of the extrusion machine lasting longer than an estimated time interval based on the temperature of the elastomer mixture at the time of the shutdown and the vulcanization time of the elastomer mixture at that temperature, and for example longer than the vulcanization time of the elastomer mixture present in the extrusion machine, the management process provides that the temperature of all components of the extrusion machine including one or more control channels is lowered to a value between 30°C and 50°C by means of the circulation of a heat transfer fluid.

[0055] Use of the method according to the invention

[0056] The management method according to the invention can, for example, be used to manage the shutdowns of an extrusion machine 10,110 used to extrude an elastomer compound M intended for the manufacture of a tire. The composition of a compound Elastomer M intended for such use includes, for example, at least one vulcanizing agent, this vulcanizing agent being sulfur or a sulfur donor. More specifically, the management method according to the invention can, for example, be used to manage the downtime of an extrusion machine 10,110 used to manufacture a profiled product P used for making tire blanks.

[0057] As illustrated in [Fig.1], an extrusion machine 10 managed using the management process according to the invention can be used to feed a manufacturing machine M1 to produce a product such as a tire blank EP.

[0058] Alternatively, and as illustrated in [Fig.2], an extrusion machine 110 managed using the management process according to the invention can be used to feed a manufacturing machine M2 enabling the transformation of the profiled product P into another semi-finished product such as a reinforced profiled product or a reinforced sheet.

[0059] The invention also relates to a method for manufacturing a product, such as a tire blank, which is implemented by a manufacturing machine M1,M2 fed by an extrusion machine 10,110 whose stops are managed using the management method according to the invention.

[0060] Advantageously, the management method according to the invention makes it possible to manage both the stoppages of an extrusion machine continuously feeding a manufacturing machine and the stoppages of an extrusion machine sequentially feeding a manufacturing machine. When an extrusion machine continuously feeds the manufacturing machine, the stoppages of the extrusion machine are, for example, due to the stoppage of the manufacturing machine, for example during a production changeover. A manufacturing machine can also operate sequentially; in this case, the stoppages of the extrusion machine are due to the sequential operation of the manufacturing machine.

[0061] Example of managing shutdowns of an extrusion machine

[0062] Figure 3 illustrates an example of managing a shutdown of an extrusion machine 10,110 according to the management method of the invention. Time is shown on the x-axis and divided into different successive time phases (PI, ..., P8). From the bottom to the top of the graph, the first curve A represents the start-up of the extrusion element 14,114; the second curve B represents the temperature of at least one component of the extrusion machine or an average of the different temperatures of the different components of the extrusion machine. Curve C represents the temperature of the elastomer mixture M inside the extrusion machine. Curve D represents the evolution of the vulcanization reaction of the elastomer mixture M inside the extrusion machine, the vulcanization reaction being in its initial state when curve D is at its highest point. and this vulcanization reaction moving towards its final state in the elastomer mixture M as the curve D descends within the graph illustrated in [Fig.3].

[0063] In a first time phase PI, the extrusion unit 14,114 is at rest, the component(s) of the extrusion machine as well as the elastomer mixture are maintained at a minimum heating temperature, for example 70°C, for example by means of the regulating channels running through the components of the extrusion machine and one or more heat transfer fluids circulating in these channels. Consequently, in this first phase PI, the vulcanization reaction of the elastomer mixture M tends to evolve towards its final state.

[0064] In a second temporal phase P2, the extrusion unit 14,114 remains stationary. The component(s) of the extrusion machine and the elastomer mixture are gradually brought, for example by means of control channels running through the components of the extrusion machine and one or more heat transfer fluids circulating in these channels, to a nominal operating temperature, for example 90°C, which is higher than the minimum heating temperature. In this second phase P2, due to the heating of the extrusion machine and the elastomer mixture, the vulcanization reaction of the elastomer mixture M tends to progress more rapidly towards its final state.

[0065] In a third temporal phase P3, the extrusion element 14,114 is set in motion and fresh elastomer mixture M is introduced into the extrusion machine. In this third phase, the component(s) of the extrusion machine, as well as the elastomer mixture, are maintained, for example by means of regulating channels running through the components of the extrusion machine and one or more heat transfer fluids circulating in these channels, at their nominal operating temperature, for example 90°C. Due to the introduction of fresh elastomer mixture M into the extrusion machine, the vulcanization reaction in the elastomer mixture present in the extrusion machine tends to return to its initial state.

[0066] In a fourth temporal phase P4 corresponding to the nominal operation of the extrusion machine, the extrusion element 14,114 reaches its nominal operating point, for example, a given rotational speed when this element is a screw. In this third phase, fresh elastomer mixture M is continuously introduced into the extrusion machine, and the component(s) of the extrusion machine, as well as the elastomer mixture, are maintained, for example, by means of regulating channels running through the components of the extrusion machine and one or more heat transfer fluids circulating in these channels, at their nominal operating temperature, for example, 90°C. Due to the continuous introduction of When a new M elastomer mixture is placed in the extrusion machine, the vulcanization reaction in the elastomer mixture stabilizes in its initial state.

[0067] At the end of the fourth phase P4, the extrusion machine stops. This stoppage occurs gradually, as the movement of the extrusion element also stops progressively. Consequently, fresh elastomer mixture M continues to enter the extrusion machine, but in decreasing quantities, until the extrusion element comes to a complete stop.

[0068] In a fifth temporal phase P5, corresponding to the complete cessation of the extrusion process, no new elastomer mixture M can be introduced into the extrusion machine. The elastomer mixture M that is trapped in the extrusion machine, as well as the component(s) of the extrusion machine, are at their nominal operating temperature, for example, 90°C. Consequently, the vulcanization reaction of the quantity of elastomer mixture M trapped in the extrusion machine begins and leaves its initial state. In order to slow down the progress of the vulcanization reaction of the quantity of elastomer mixture M trapped in the extrusion machine, the control method provides for cooling this non-zero quantity of elastomer mixture M that is still present inside the extrusion machine.For example, the management process involves lowering the temperature of at least one of the extrusion machine components using control channels running through the component(s) to be cooled. In the example shown in [Fig. 3], the heat transfer fluid(s) lower the temperature of the component(s) and the elastomer compound trapped in the extrusion machine to the minimum heating temperature, for example, 70°C. The heat transfer fluid(s) are not used to lower the temperature of the component(s) and the elastomer compound trapped in the extrusion machine further in order to allow for a faster restart of the extrusion machine after it has stopped and to save time and energy.

[0069] During the sixth temporal phase P6, corresponding substantially to the shutdown period of the extrusion machine, the extrusion unit is stopped and the component(s) of the extrusion machine, as well as the elastomer mixture trapped within the extrusion machine, are maintained at the minimum heating temperature, for example, 70°C. Consequently, and as illustrated in [Fig. 3], the vulcanization reaction of the quantity of elastomer mixture M trapped within the extrusion machine continues to progress towards its final state, but at a slower pace.

[0070] The seventh and eighth temporal phases P7 and P8 correspond respectively to the second and third temporal phases P2 and P3.

[0071] In the seventh temporal phase P7, the extrusion unit 14,114 is still stopped, the component(s) of the extrusion machine as well as the mixing The elastomers are gradually brought, for example by means of regulating channels running through the components of the extrusion machine and one or more heat transfer fluids circulating in these channels, to their nominal operating temperature, for example 90°C. In this seventh phase P7, due to the heating of the extrusion machine and the elastomer mixture, the vulcanization reaction of the elastomer mixture M tends to evolve more rapidly towards its final state.

[0072] In the eighth temporal phase P8, the extrusion element 14,114 is set in motion and fresh elastomer mixture M is introduced into the extrusion machine. In this eighth phase, the component(s) of the extrusion machine, as well as the elastomer mixture, are maintained, for example by means of regulating channels running through the components of the extrusion machine and one or more heat transfer fluids circulating in these channels, at their nominal operating temperature, for example 90°C. Due to the introduction of fresh elastomer mixture M into the extrusion machine, the vulcanization reaction in the elastomer mixture present in the extrusion machine tends to return to its initial state.

[0073] Variants

[0074] More generally, in the fourth time phase P4 corresponding to the nominal operation of the extrusion machine, the component(s) of the extrusion machine as well as the elastomer mixture are brought progressively to a nominal operating temperature which can be between 80°C and 100°C.

[0075] More generally, during the fifth temporal phase P5, corresponding to the complete shutdown of the extrusion unit's movement, the control process may provide that the temperature of the extrusion machine component(s) and the elastomer mixture trapped within the extrusion machine can be lowered to a value between 50 and 70°C. During a prolonged shutdown of the extrusion machine, for example, for several minutes, the control process may provide that the temperature of the extrusion machine component(s) and the elastomer mixture trapped within the extrusion machine can be lowered to a value between 30°C and 50°C.This reduction in the temperature of the component(s) of the extrusion machine and the elastomer mixture to a value between 30°C and 50°C can be carried out after an initial plateau at a value between 50 and 70°C, or directly from the nominal operating temperature which can be between 80°C and 100°C.

[0076] For certain extrusion machines having a higher extrusion flow rate and in which a larger quantity of elastomer mixture is blocked during In the event of a stoppage of the extrusion machine, the management process may provide for directly lowering the temperature of the component(s) of the extrusion machine and of the elastomer mixture blocked in the extrusion machine to a value between 30°C and 50°C.

Claims

Demands

1. A method for managing a shutdown of an extrusion machine used to extrude an elastomeric mixture whose composition includes at least one vulcanizing agent, the extrusion machine delivering the elastomeric mixture in the form of a profiled product, the extrusion machine comprising a body and an extrusion element driven in motion within this body, the body comprising at least one inlet through which the elastomeric mixture is introduced, the body comprising an outlet equipped with a tool for shaping the elastomeric mixture, the movement of the extrusion element within said body driving the elastomeric mixture towards the outlet of said body, the management method being characterized in that, during a shutdown of the extrusion machine resulting in a stoppage of the movement of the extrusion element and while a non-zero quantity of elastomeric mixture is still present inside the extrusion machine,The management process involves cooling at least a portion of the non-zero quantity of elastomer mixture M that is still present inside the extrusion machine.

2. A method for managing a stoppage of an extrusion machine according to claim 1, wherein, during a stoppage of the extrusion machine resulting in a stoppage of the movement of the extrusion member and while a non-zero quantity of elastomer mixture is still present inside the extrusion machine, the management method provides for lowering the temperature of at least one of these components of the extrusion machine: the body, the extrusion member, or the forming tool.

3. A method for managing a shutdown of an extrusion machine according to claim 2, wherein the body, the extrusion element and / or the shaping tool are components of the extrusion machine traversed by at least one regulating channel allowing the circulation of a heat transfer fluid, during a shutdown of the extrusion machine resulting in a cessation of the movement of the extrusion element and while a non-zero quantity of elastomer mixture is still present inside the machine In extrusion, the management process provides that the temperature of the heat transfer fluid circulating in at least one of the control channels is lowered to a value lower than the temperature of the component of the extrusion machine which is traversed by this control channel.

4. Method of managing a shutdown of an extrusion machine according to claim 3, wherein the temperature of the heat transfer fluid circulating in at least one control channel is lowered as soon as the extrusion machine is stopped or when the duration of the shutdown of the extrusion machine is greater than a time interval estimated as a function of the temperature of the elastomer mixture at the time of the shutdown of the extrusion machine and the vulcanization time of the elastomer mixture at that temperature.

5. Method of managing a shutdown of an extrusion machine according to any one of claims 3 or 4, wherein, during a shutdown of the extrusion machine, the temperature of the heat transfer fluid circulating in at least one control channel of the body of the extrusion machine is lowered to a value lower than the temperature of that body.

6. Method of managing a stoppage of an extrusion machine according to any one of claims 3 to 5, wherein, the body of the extrusion machine comprising different sections and at least one of these sections being traversed by a control channel allowing the circulation of a heat transfer fluid, during a stoppage of the extrusion machine, the temperature of the heat transfer fluid circulating in the control channel of at least one section is lowered to a value lower than the temperature of that section.

7. A method for managing a shutdown of an extrusion machine according to any one of claims 3 to 6, wherein the heat transfer fluid circulating in at least one control channel has a temperature of at most 70°C as long as the duration of the shutdown of the extrusion machine is less than a time interval estimated as a function of the temperature of the elastomer mixture at the time of the shutdown of the extrusion machine and the vulcanization time of the elastomer mixture at that temperature, for example less than 75% of the vulcanization time of the elastomer mixture present in the extrusion machine.

8. A method for managing a shutdown of an extrusion machine according to claim 7, wherein, when the duration of the shutdown of the If the extrusion machine is less than an estimated time interval based on the temperature of the elastomer mixture at the time the extrusion machine is stopped and the vulcanization time of the elastomer mixture at that temperature, for example less than 75% of the vulcanization time of the elastomer mixture present in the extrusion machine, the temperature of at least one component of the extrusion machine is lowered to a value between 50°C and 70°C by circulating a heat transfer fluid in that component.

9. A method for managing a shutdown of an extrusion machine according to any one of claims 3 to 8, wherein a heat transfer fluid having a temperature of at most 50°C circulates in at least one control channel when a shutdown of the extrusion machine has a duration greater than a time interval estimated as a function of the temperature of the elastomer mixture at the time of the shutdown of the extrusion machine and the vulcanization time of the elastomer mixture at that temperature, for example greater than the vulcanization time of the elastomer mixture present in the extrusion machine.

10. A method for managing a shutdown of an extrusion machine according to claim 9, wherein a heat transfer fluid having a temperature between 30°C and 50°C, and preferably between 35°C and 45°C, circulates in at least one control channel when a shutdown of the extrusion machine has a duration greater than a time interval estimated as a function of the temperature of the elastomer mixture at the time of the shutdown of the extrusion machine and the vulcanization time of the elastomer mixture at that temperature, for example greater than the vulcanization time of the elastomer mixture present in the extrusion machine.

11. A method for managing a shutdown of an extrusion machine according to claim 9 or 10, wherein, during a shutdown of the extrusion machine lasting longer than a time interval estimated based on the temperature of the elastomer mixture at the time of the shutdown and the vulcanization time of the elastomer mixture at that temperature, for example, longer than the vulcanization time of the elastomer mixture present in the extrusion machine, the temperature of at least one component of the extrusion machine is lowered to a value between 30°C and 50°C thanks to the circulation of a heat transfer fluid in this component.

12. A method for managing a shutdown of an extrusion machine according to any one of the preceding claims, wherein the vulcanizing agent is sulfur or a sulfur donor.

13. A method for manufacturing a product from at least one profiled elastomer compound product, this manufacturing method being implemented by a manufacturing machine fed by an extrusion machine whose stops are managed by a management method according to any one of claims 1 to 12.

14. A manufacturing method according to claim 13, wherein the product made by the manufacturing machine is a tire blank.

15. A manufacturing method according to claim 13 or 14, wherein the extrusion machine continuously feeds the manufacturing machine, the stops of the extrusion machine due to the stoppage of the manufacturing machine being managed using the management method according to any one of claims 1 to 12.

16. A manufacturing method according to claim 13 or 14, wherein the extrusion machine sequentially feeds the manufacturing machine, the stops of the extrusion machine due to the sequential operation of the manufacturing machine being managed using the management method according to any one of claims 1 to 12.

Images