Heating system for heating plastic material preforms

Abstract

A heating system for heating plastic material preforms upstream of a blow molding machine or a stretch blow molding machine, comprising a heating module configured to be crossed by a plurality of preforms advancing along a transfer line, the heating module comprising a plurality of heating elements arranged along a plane substantially parallel to a plane including the axes of the preforms configured to cross the heating module, the heating module comprising a first heating zone proximate to a support area of ​​the neck of the preform and comprising at least one first heating element of the plurality of heating elements, and at least one second heating zone adjacent to the first heating zone and arranged in a passage zone of the tubular body of the preform and comprising at least one second heating element of the plurality of heating elements, the heating system further comprising at least one first temperature sensor and at least one second temperature sensor.

Description

[Technical Field]

[0001] The present invention relates to a heating system for heating plastic material preforms, preferably arranged upstream of a blow molding machine or a stretch blow molding machine, the heating system being configured to be traversed by a plurality of preforms advancing along a transfer line. The present invention also relates to an oven comprising said heating system, a blow molding plant for blowing containers comprising said oven, and an associated process for heating preforms by means of said heating system. [Background technology]

[0002] It is known that the blow or stretch-blow process must be preceded by a temperature conditioning step of the preform in an oven, where the preform is heated to a predefined temperature for blowing by a specific heating module using multiple heating elements, e.g. infrared lamps. The purpose of heating the preform before the blow or stretch-blow molding step is to bring the preform material to the right temperature in order to obtain a high-quality molded container.

[0003] Typically, the heating modules are symmetrically arranged on two benches, defining two tunnels connected by a curved stretch. The heating elements of each heating module are arranged along a plane substantially parallel to the plane containing the axis of the preforms advancing along the respective benches. Preforms, moved by a transport chain with chucks, traverse the heating modules of the two tunnels.

[0004] During the preform's passage through these heating modules, the neck of the preform must remain substantially cool, i.e., below its softening temperature, so that it is not distorted by the subsequent blowing operation.

[0005] It is known that the heating of the body of the preform is achieved by the combined effects of: - thermal radiation (convection) penetrating the thickness of the body of the preform; - contact with the ambient air heated inside the furnace (conduction); - Heat diffusion to the preform wall by conduction (stabilization / temperature reversal).

[0006] It is also important to ventilate the interior of the heating module and the exterior surfaces of the preforms within it with a preset airflow to prevent the material on the exterior surface of the preform from becoming too hot and crystallizing while the material inside the preform is waiting to reach the blowing temperature. This ventilation maintains the ambient temperature of the heating module at a desired level, removes excess heat, for example from infrared radiation not captured by the preform, and moderates the temperature of the preform skin. This desired level of the internal temperature of the heating module is one that can optimize its energy performance. It is well known that this energy performance is correlated with the thickness of the preform. The ventilation flow rate must be sufficient to eliminate this correlation and is preferably well-distributed within the heating module to ensure homogeneous treatment of the entire surface of the preform wall that needs to be heated. Summary of the Invention [Problem to be solved by the invention]

[0007] Disadvantageously, temperature control of the preform immediately upstream of the molding machine is performed by a single temperature sensor attached to the last heating module of the furnace. In some cases, feedback control based on this single measurement point to adjust the power of the heating element of this last heating module results in a suboptimal temperature profile throughout the preform, especially at the periphery of the preform.

[0008] Therefore, a need is felt to provide a heating system that can overcome the above-mentioned drawbacks. [Means for solving the problem]

[0009] The object of the present invention is to provide a heating system for heating a preform upstream of a blow molding or stretch blow molding machine or press, which allows better regulation of the power of its heating elements, so that an optimal temperature profile can be obtained throughout the preform, and in particular along each zone of the body of the preform.

[0010] Another object of the present invention is to provide a furnace with several heating systems, in which at least one of said heating systems is provided according to the solution of the present invention in order to be able to better regulate the power of its heating elements and / or the power of the heating elements of further heating systems, also of known type, arranged upstream of the heating system of the present invention.

[0011] It is a further object of the present invention to provide an associated preform heating process using said heating system.

[0012] The present invention achieves these and other objects that will become apparent in the light of this description by a heating system for heating plastic material preforms upstream of a blow moulding machine or stretch blow moulding machine, said system comprising a heating module arranged to be traversed by a plurality of preforms advancing along a transfer line, the heating module includes a plurality of heating elements arranged along a plane substantially parallel to a plane containing an axis of the preform configured to traverse the heating module; The heating module is a first heating zone proximate a support area of ​​the neck of the preform and comprising at least one first heating element of the plurality of heating elements; at least one second heating zone disposed adjacent to the first heating zone in a passage zone of the tubular body of the preform, the second heating zone comprising at least one second heating element of the plurality of heating elements; Equipped with The system is at least one first temperature sensor disposed in the first heating zone external to the heating module; at least one second temperature sensor disposed in the at least one second heating zone external to the heating module; Further provided with an electronic control device configured to receive temperature data detected by both the at least one first temperature sensor and the at least one second temperature sensor, compare the temperature data with predetermined target temperatures of the first heating zone and the second heating zone, and act as a feedback by adjusting power of the at least one first heating element and the at least one second heating element; Both the at least one first temperature sensor and the at least one second temperature sensor are located immediately downstream of the heating module.

[0013] The second heating zone adjacent to the first heating zone is positioned below the first heating zone when the transfer line is configured to advance the preform with the neck opening facing upward, or is positioned above the first heating zone when the transfer line is configured to advance the preform with the neck opening facing downward.

[0014] Another aspect of the invention relates to an oven for heating plastic material preforms, configured to be positioned upstream of a blow molding machine or a stretch blow molding machine, the oven comprising a plurality of heating systems with respective heating modules arranged on at least one bench, the oven being configured to be traversed by the plurality of preforms, Each heating module includes a plurality of heating elements arranged along a plane substantially parallel to a plane containing an axis of a preform configured to advance along at least one bench; At least one of said heating systems is provided according to the solution of the invention, The electronic control device of the at least one heating system of the present invention is configured to receive the temperature data detected by both the at least one first temperature sensor and the at least one second temperature sensor, compare the temperature data with predetermined target temperatures of the first heating zone and the second heating zone of the heating module, and act as feedback by adjusting the power of the at least one first heating element and the at least one second heating element of the heating module and / or act as feedback by adjusting the power of multiple heating elements in one or more further heating systems of the furnace arranged upstream of the at least one heating system provided according to the present invention.

[0015] A further aspect of the invention is a blow moulding plant for blow moulding plastic material containers, comprising: the furnace; Blow molding machine or stretch blow molding machine The present invention relates to a blow molding plant comprising:

[0016] Finally, a final aspect of the invention relates to a process for heating plastic material pre-forms by means of the heating system of the invention, said process comprising: detecting a temperature of the preform in the first heating zone with the at least one first temperature sensor; detecting a temperature of the preform in the at least one second heating zone with the at least one second temperature sensor; Including, Temperature data detected by both the at least one first temperature sensor and the at least one second temperature sensor is received by the electronic control device, which compares the detected temperature data with predetermined target temperatures of the first heating zone and the second heating zone and acts as a feedback by adjusting power of the at least one first heating element and the at least one second heating element.

[0017] Advantageously, the heating system of the present invention is highly flexible, allowing for precise control of two or more heating zones where a defined thermal gradient is desired on the preform based on different preform geometries (e.g., preforms with different thickness zones along their longitudinal axis) or based on the length of the preform, thereby achieving a desired consistent distribution of plastic on the container despite thermal "turbulence" determined by varying air temperatures and "edge" effects that may affect the thermodynamic / thermal profile of the preform.

[0018] Further features and advantages of the present invention will become more apparent in light of the detailed description of illustrative, but non-exclusive, embodiments thereof.

[0019] The dependent claims describe particular embodiments of the invention.

[0020] In describing the present invention, reference is made to the accompanying drawings, which are provided as non-limiting examples. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic layout of a heating module bench of a furnace according to the present invention; [Figure 2] 1 is a schematic cross-sectional view of a first embodiment of a heating system according to the present invention; [Figure 3] FIG. 2 is a schematic cross-sectional view of a first modified example of the first embodiment. [Figure 4]FIG. 10 is a schematic cross-sectional view of a second modified example of the first embodiment. [Figure 5] 2 is a schematic cross-sectional view of a second embodiment of a heating system according to the present invention; [Figure 6] FIG. 10 is a schematic cross-sectional view of a first modified example of the second embodiment. [Figure 7] FIG. 10 is a schematic cross-sectional view of a second modified example of the second embodiment. [Figure 8] 1 is a diagram of a schematic layout of two heating module benches of a furnace according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The same reference numbers and letters in the figures indicate the same elements or components.

[0023] 2 to 7, an embodiment of a heating system 2 of the present invention for heating preforms 5 at the inlet of a blow molding machine or stretch blow molding machine 3 is shown.

[0024] The preforms to be heated are made of plastic materials such as PET, PP, PLA, PVC, although the system of the present invention can also be used to heat preforms made of different plastic materials or preforms made of some combination of these materials.

[0025] In all embodiments of the present invention, the heating system 2 comprises a heating module 4 configured to be traversed by a plurality of preforms 5 advancing along a transfer line 14 .

[0026] The heating module 4 is provided with a plurality of heating elements 12, 13 arranged along a plane substantially parallel to a plane containing the axis of the preform 5 across the heating module.

[0027] In a first embodiment of the heating system of the invention, the heating module 4 comprises (FIGS. 2 to 4): a first heating zone 10 located near the support area of ​​the neck of the preform and comprising at least one first heating element 12; and a second heating zone 11 arranged below the first heating zone 10 in the passage zone of the tubular body of the preform, for example a single second heating zone 11 comprising at least one second heating element 13;

[0028] 2 to 4, the transfer line is configured to advance the preforms with their neck openings facing upward. Alternatively, if the transfer line is configured to advance the preforms with their neck openings facing downward, it is not excluded that the second heating zone 11 is located above the first heating zone 10.

[0029] In this first embodiment, the heating system 2 further comprises: at least one first temperature sensor 8 arranged in a first heating zone 10 outside the heating module 4; at least one second temperature sensor 9 arranged in a second heating zone 11 outside the heating module 4, and an electronic control device 7 for receiving temperature data detected by both the at least one first temperature sensor 8 and the at least one second temperature sensor 9, for comparing the temperature data with predetermined target temperatures of the first heating zone 10 and the second heating zone 11, and for acting as feedback by adjusting the power of the at least one first heating element 12 and the at least one second heating element 13.

[0030] In the variant of FIG. 2, the heating system 2 comprises: - only one first temperature sensor 8 in the first heating zone 10, and - only one second temperature sensor 9 in the second heating zone 11;

[0031] In this variant, the electronic control device 7 receives temperature data detected by the first temperature sensor 8 and the second temperature sensor 9, compares the temperature data with predetermined target temperatures of the first heating zone 10 and the second heating zone 11, and acts as a feedback by adjusting the power of the first heating element 12 by means of a power regulator 18 and the power of the second heating element 13 by means of a power regulator 19. Alternatively, one power regulator 18 can be provided per heating element 12 and one power regulator 19 can be provided per second heating element 13.

[0032] In the variant of FIG. 3, the heating system 2 comprises: - only one first temperature sensor 8 in the first heating zone 10, and - three second temperature sensors 9 in the second heating zone 11;

[0033] Alternatively, a single first temperature sensor 8 and two or more second temperature sensors 9 may be provided; or two or more first temperature sensors 8 and a single second temperature sensor 9 may be provided; or two or more first temperature sensors 8 and two or more second temperature sensors 9 may be provided.

[0034] In this variant, the electronic control device 7 receives temperature data detected by a single first temperature sensor 8, or by the first temperature sensor 8 and the second temperature sensor 9, or by a single temperature sensor 9, compares said temperature data with predetermined target temperatures of the first heating zone 10 and the second heating zone 11, and acts as a feedback by adjusting the power of the first heating element 12 by power regulator 18 and the power of the second heating element 13 by power regulator 19. Alternatively, again, one power regulator 18 can be provided per heating element 12 and one power regulator 19 can be provided per second heating element 13.

[0035] In the variant of FIG. 4, the heating system 2 comprises a first temperature sensor 8 for each first heating element 12 and a second temperature sensor 9 for each second heating element 13 .

[0036] In this variant, the electronic control device 7 receives temperature data detected by the first temperature sensor 8 and the second temperature sensor 9, compares said temperature data with predetermined target temperatures of the first heating zone 10 and the second heating zone 11, and acts as a feedback by adjusting the power of the first heating elements 12 by respective power regulators 18 and the power of the second heating elements 13 by respective power regulators 19. Alternatively, a single power regulator can be provided for all first heating elements 12 and a single power regulator 19 can be provided for all second heating elements 13.

[0037] 2 to 4, by way of non-limiting example only, the first heating zone 10, proximal to the support area of ​​the neck of the preform, comprises two heating elements 12, while the second heating zone 11, in the passage zone of the tubular body of the preform, comprises six heating elements 13. There can be fewer than two or more than three heating elements 12, and fewer than six or more than six heating elements 13.

[0038] Advantageously, the temperature sensors 8 and 9 are arranged immediately downstream of the heating module 4 .

[0039] In particular, therefore, no components are provided between the outlet section of the heating module 4 and the temperature sensor.

[0040] For example, temperature sensors 8 , 9 may also be located upstream of a transfer wheel (not shown) or other transfer means that transfers the preforms from the heating module 4 to the blow moulding machine or stretch blow moulding machine 3 .

[0041] This configuration maximizes the feedback speed while minimizing the feedback power adjustment time of the heating elements 12, 13. Furthermore, this configuration improves the quality of the measurement both with respect to solutions in which the temperature sensor is integrated into the wall of the heating module facing the inside of the module, which may result in erroneous temperature measurements, and with respect to solutions in which the temperature sensor is placed further downstream relative to the heating modules, especially further downstream than the last heating module, which results in a longer path for the preforms between the furnace and the molding machine, and therefore a longer transit time between preform thermal conditioning and container molding.

[0042] Furthermore, the temperature sensors 8 and 9 face the outside of the heating module 4 to avoid measurements being taken on the preform while it is exposed to the radiation of the heating elements 12,13.

[0043] This configuration allows the use of any temperature sensor, for example any pyrometer or thermal camera, without the need to use a specific material that does not absorb radiation at the emission wavelength of the heating element.

[0044] Preferably, the outlet section of the heating module 4 is provided with a shield (not shown) to prevent the presence of residual heat radiation from the heating module from altering the temperature measurement and, accordingly, causing errors in the setting of the heating profile.

[0045] In a second embodiment of the heating system of the invention, the heating module 4 comprises (FIGS. 5 to 7): a first heating zone 10 located near the support area of ​​the neck of the preform and comprising at least one first heating element 12; a second heating zone 11 arranged below the first heating zone 10 in the passage zone of the tubular body of the preform, the second heating zone 11 comprising at least one second heating element 13; and a third heating zone 15 arranged below said second heating zone 11 in the bottom passage zone of the preform, said third heating zone 15 comprising at least one third heating element 16;

[0046] 5 to 7, the transfer line is configured to advance the preform with the neck opening facing upward. Alternatively, if the transfer line is configured to advance the preform with the neck opening facing downward, it is not excluded that the second heating zone 11 is located above the first heating zone 10 and the third heating zone 15 is located above the second heating zone 11.

[0047] In this second embodiment, the heating system 2 further comprises: at least one first temperature sensor 8 arranged in a first heating zone 10 outside the heating module 4; - at least one second temperature sensor 9 arranged in a second heating zone 11 outside the heating module 4, at least one third temperature sensor 17 arranged in the third heating zone 15 outside the heating module 4, and an electronic control device 7 for receiving temperature data detected by the at least one first temperature sensor 8, the at least one second temperature sensor 9, and the at least one third temperature sensor 17, comparing the temperature data with predetermined target temperatures of the first heating zone 10, the second heating zone 11, and the third heating zone, respectively, and acting as a feedback by adjusting the power of the at least one first heating element 12, the at least one second heating element 13, and the at least one third heating element 16.

[0048] In the variant of FIG. 5, the heating system 2 comprises: - only one first temperature sensor 8 in the first heating zone 10; - only one second temperature sensor 9 in the second heating zone 11, and - only one third temperature sensor 17 in the third heating zone 15;

[0049] In this variant, electronic control device 7 receives temperature data detected by first temperature sensor 8, second temperature sensor 9 and third temperature sensor 17, compares the temperature data with predetermined target temperatures of first heating zone 10, second heating zone 11 and third heating zone 15, respectively, and acts as a feedback by adjusting the power of first heating element 12 by power regulator 18, the power of second heating element 13 by power regulator 19 and the power of third heating element 16 by power regulator 20. Alternatively, one power regulator 18 for each heating element 12, one power regulator 19 for each second heating element 13 and one power regulator 20 for each third heating element 16 can be provided.

[0050] In the variant of FIG. 6, the heating system 2 comprises: - only one first temperature sensor 8 in the first heating zone 10; - two second temperature sensors 9 in the second heating zone 11, and - only one third temperature sensor 17 in the third heating zone 15;

[0051] Alternatively, the following may be provided: - only one first temperature sensor 8, three or more second temperature sensors 9 and only one third temperature sensor 17, or two or more first temperature sensors 8, only one second temperature sensor 9 and only one third temperature sensor 17, or - only one first temperature sensor 8, only one second temperature sensor 9 and two or more third temperature sensors 17, or two or more first temperature sensors 8, two or more second temperature sensors 9 and only one third temperature sensor 17, or two or more first temperature sensors 8, only one second temperature sensor 9 and two or more third temperature sensors 17, or - only one first temperature sensor 8, two or more second temperature sensors 9, and two or more third temperature sensors 17, or two or more first temperature sensors 8, two or more second temperature sensors 9, and two or more third temperature sensors 17.

[0052] In this variant, the electronic control device 7 receives temperature data detected by the single first temperature sensor 8 or multiple first temperature sensors 8, by the multiple second temperature sensors 9 or single temperature sensor 9, and by the multiple third temperature sensor 17 or single temperature sensor 17, compares the temperature data with predetermined target temperatures of the first heating zone 10, the second heating zone 11, and the third heating zone 15, respectively, and acts as a feedback by adjusting the power of the first heating element 12 by power regulator 18, the power of the second heating element 13 by power regulator 19, and the power of the third heating element 16 by power regulator 20. Alternatively, one power regulator 18 can be provided for each heating element 12, one power regulator 19 for each second heating element 13, and one power regulator 20 for each third heating element 16.

[0053] In the variant of Figure 7, the heating system 2 comprises a first temperature sensor 8 for each first heating element 12, a second temperature sensor 9 for each second heating element 13, and a third temperature sensor 17 for each third heating element 16.

[0054] In this variation, the electronic control device 7 receives temperature data detected by the first temperature sensor 8, the second temperature sensor 9, and the third temperature sensor 17, compares said temperature data to predetermined target temperatures for the first heating zone 10, the second heating zone 11, and the third heating zone 15, respectively, and acts as a feedback by adjusting the power of the first heating elements 12 by respective power regulators 18, the power of the second heating elements 13 by respective power regulators 19, and the power of the third heating elements 16 by respective power regulators 20. Alternatively, as shown in Figure 7, a single power regulator can be provided for all first heating elements 12, a single power regulator 19 can be provided for all second heating elements 13, and a single power regulator 20 can be provided for all third heating elements 16.

[0055] 5 to 7, by way of non-limiting example only, the first heating zone 10 near the support area of ​​the neck of the preform comprises two heating elements 12, the second heating zone 11 in the pass-through zone of the tubular body of the preform comprises four heating elements 13, and the third heating zone 15 in the pass-through zone of the bottom of the preform comprises two third heating elements 16. There can be fewer than two or more than three heating elements 12, fewer than four or more than five heating elements 13, and fewer than two or more than three heating elements 16.

[0056] Advantageously, as in the first embodiment of the invention, the temperature sensors 8 , 9 and 17 are arranged immediately downstream of the heating module 4 .

[0057] In particular, therefore, no components are provided between the outlet section of the heating module 4 and the temperature sensor.

[0058] For example, temperature sensors 8 , 9 , 17 may also be located upstream of a transfer wheel or other transfer means that transfers the preforms from the heating module 4 to the blow moulding machine or stretch blow moulding machine 3 .

[0059] Furthermore, the temperature sensors 8, 9, 17 face the outside of the heating module 4 to avoid measurements being taken on the preforms while they are exposed to the radiation of the heating elements 12, 13, 16. Preferably, the outlet section of the heating module 4 is provided with a shield (not shown) to avoid the presence of residual thermal radiation of the heating module altering the temperature measurements and thus causing corresponding errors in the setting of the heating profile.

[0060] In all embodiments of the present invention, the heating elements 12, 13, 16 may be infrared lamps arranged along a first plane substantially parallel to the plane containing the axis of the preform arranged to cross the heating module. As an alternative to infrared lamps, LED lamps, laser lamps, NIR lamps or other suitable heating elements may also be used.

[0061] Similarly, the temperature sensors 8, 9, 17 are arranged along a second plane substantially parallel to the plane containing the axis of the preform and are configured to traverse said heating module, along said first plane along which the heating elements 12, 13, 16 are arranged.

[0062] A further aspect of the invention relates to an oven 1 for heating plastics material preforms, shown diagrammatically in FIG. 1, arranged upstream of a blow moulding or stretch blow moulding machine 3.

[0063] Such a furnace 1 is arranged to be traversed by preforms 5 advancing along a transfer line 14 and comprises a plurality of heating systems 2, 2' with respective heating modules 4, 4' arranged on at least one bench.

[0064] At least one heating system, designated by reference number 2, is provided according to the invention in accordance with one of the variants described above.

[0065] The remaining heating system is of a conventional type and is designated by the reference numeral 2'. Each heating module 4' is provided with a number of heating elements 6 arranged along a plane substantially parallel to the plane containing the axis of the preform 5 advancing along the bench.

[0066] Such a heating module 4' can be provided according to any one of the solutions known from the prior art.

[0067] Advantageously, the electronic control device 7 of at least one heating system 2 according to the invention is configured to: receiving temperature data detected by both the at least one first temperature sensor 8 and the at least one second temperature sensor 9, and possibly also by the at least one third temperature sensor 17; - comparing said temperature data with predetermined target temperatures of said first heating zone 10 and said second heating zone 11, and possibly also said third heating zone 15, of the heating module 4; and - acting as a feedback by adjusting the power of the at least one first heating element 12 and the at least one second heating element 13, and possibly also the at least one third heating element 16, of the heating module 4, and / or acting as a feedback by adjusting the power of a plurality of heating elements 6 in the remaining heating system 2' of the furnace 1, which are arranged upstream of the at least one heating system 2 according to the invention.

[0068] The example of Figure 1 shows a furnace 1 with a single linear bench of heating systems 2, 2'. Arrow A indicates the direction of advance of the preforms 5 across the respective heating modules 4, 4'.

[0069] In this non-limiting example, the heating system 2 according to the invention is the last system on the bench and is located immediately upstream of the former 3, which may be a linear or rotary machine.

[0070] Alternatively, the heating system 2 according to the invention can be placed in an intermediate position within the bench.

[0071] In a furnace configuration (not shown) having two benches connected by a connecting stretch section, e.g. a curved or serpentine stretch section, the heating system according to the invention can be positioned immediately upstream of the stretch blow molding machine 3, immediately downstream of the second bench of the heating system and / or at an intermediate position to the second bench and / or at an intermediate position to the first bench.

[0072] To enhance control of the temperature of the preforms along the transfer line, a first detection device for detecting the temperature of the preforms may be located at the entrance of the first bench and a second detection device for detecting the temperature of the preforms may be located at the connecting segment.

[0073] More specifically, as shown diagrammatically in FIG. 8, the furnace 1 is equipped with two benches 30 , 31 connected by a connecting stretch 32 .

[0074] A second bench 31 proximal to the blow molding machine or stretch blow molding machine 3 is provided with a plurality of heating systems 2, 2' including respective heating modules 4, 4' configured to be traversed by the preforms 5 advancing along the transfer line 14.

[0075] At least one heating system, designated by reference number 2, is provided according to the invention according to one of the variants described above.

[0076] The remaining heating system is of a conventional type, designated by the reference numeral 2'. Each heating module 4' is provided with a plurality of heating elements 6 arranged along a plane substantially parallel to the plane containing the axis of the preform 5 advancing along the second bench 31.

[0077] Such a heating module 4' can be provided according to any one of the solutions known from the prior art.

[0078] Preferably, the heating system 2 according to the invention is the last system of the second bench 31 closest to the molding machine 3 .

[0079] A first bench 30 distal to the blow moulding or stretch blow moulding machine 3 is equipped with a number of heating systems 2'' each including a heating module 4'' of conventional type.

[0080] Each heating module 4 ″ is provided with a plurality of heating elements 6 ′ arranged along a plane substantially parallel to the plane containing the axis of the preform 5 advancing along the first bench 30 .

[0081] Such a heating module 4'' can be provided according to any one of the solutions known from the prior art.

[0082] Advantageously, at least one temperature sensor 33 , preferably a single temperature sensor 33 , is arranged in said connecting stretch 32 , preferably immediately downstream of the first bench 30 .

[0083] A further electronic control device 37 is configured to receive temperature data detected by said at least one temperature sensor 33, compare said temperature data with a predetermined target temperature of the preform at the outlet of the first bench 30 and act as feedback by adjusting the power of the heating elements 6' of the heating modules 4'' by respective power regulators.

[0084] Preferably, at least one further temperature sensor 34 , optionally a single further temperature sensor 34 , is placed at the entrance of the first bench 30 .

[0085] The further electronic control device 37 is further configured to receive temperature data detected by the at least one further temperature sensor 34, compare said temperature data with a predetermined target temperature of the preform at the inlet of the first bench 30, and optimize the power of the heating element 6' of the heating module 4'' before the preform passes over it.

[0086] In a preferred variant, the further electronic control device 37 cooperates with the electronic control device 7 and transmits temperature data detected by the at least one temperature sensor 33 to the electronic control device 7 in order to optimize the power of the heating elements 12, 13, 16, 6 of the heating modules 4, 4' of the second bench 31 before the preform passes through the heating modules.

[0087] A further aspect of the invention relates to a process for heating a plastics material pre-form by means of the heating system of the invention, said process comprising: - detecting the temperature of the preform in the first heating zone 10 by means of said at least one first temperature sensor 8; - detecting the temperature of the preforms in the at least one second heating zone 11 by means of the at least one second temperature sensor 9; - optionally detecting the temperature of the preforms in said at least one third heating zone 15 by means of said at least one third temperature sensor 17; wherein temperature data detected by both the at least one first temperature sensor 8 and the at least one second temperature sensor 9, and optionally further by the at least one third temperature sensor 17, is received by an electronic control device 7, which compares the detected temperature data with predetermined target temperatures of the first heating zone 10 and the second heating zone 11, and optionally a third heating zone 15, and acts as a feedback by adjusting the power of the at least one first heating element 12 and the at least one second heating element 13, and optionally the at least one third heating element 16.

[0088] A further aspect of the present invention relates to a process for heating plastic material preforms by means of a furnace as shown diagrammatically in Figure 8, in which process detection of the temperature of the preforms, preferably in the connecting stretch 32 immediately downstream of the first bench 30, by said at least one temperature sensor 33 is further provided, the temperature data detected by said at least one temperature sensor 33 being received by a further electronic control device 37 which compares said temperature data with a predetermined target temperature of the preform surface at the outlet of the first bench 30 and acts as feedback by adjusting the power of the heating elements 6' of one or more heating modules 4'' by means of a special power regulator.

[0089] Preferably, the further electronic control device 37 cooperates with the electronic control device 7 by transmitting temperature data detected by the at least one temperature sensor 33 to the electronic control device 7 so that the electronic control device 7 can optimize, at the second bench 31, the power of the heating elements 12, 13 and 16 of each heating module 4 of the heating system 2 and / or the power of the plurality of heating elements 6 in one or more of the further heating systems 2'.

[0090] Finally, optionally and preferably, said at least one further temperature sensor 34 detects the temperature of the surface of the preform at the inlet of the first bench 30 .

[0091] In this case, the temperature data detected by the at least one further temperature sensor 34 is received by a further electronic control device 37 which compares said temperature data with a predetermined target temperature of the surface of the preform at the inlet of the first bench 30 in order to optimize the power of the heating element 6' of the heating module 4''.

Claims

1. A heating system (2) for heating plastic material preforms upstream of a blow molding machine or stretch blow molding machine (3), comprising: a heating module (4) configured to be traversed by a plurality of preforms (5) advancing along a transfer line (14); the heating module is provided with a plurality of heating elements (12, 13) arranged along a plane substantially parallel to a plane including an axis of the preform arranged to traverse the heating module; The heating module (4) a first heating zone (10) proximate a support area of ​​the neck of the preform and comprising at least one first heating element (12) of the plurality of heating elements; at least one second heating zone (11) disposed adjacent to the first heating zone (10) in a passage zone of the tubular body of the preform, the second heating zone (11) comprising at least one second heating element (13) of the plurality of heating elements; Equipped with The heating system (2) comprises: at least one first temperature sensor (8) arranged in the first heating zone outside the heating module (4); at least one second temperature sensor (9) arranged in the at least one second heating zone outside the heating module (4); Further provided with an electronic control device (7) configured to receive temperature data detected by both the at least one first temperature sensor (8) and the at least one second temperature sensor (9), compare the temperature data with predetermined target temperatures of the first heating zone (10) and the at least one second heating zone (11), and act as a feedback by adjusting the power of the at least one first heating element (12) and the at least one second heating element (13); A heating system (2), wherein both the at least one first temperature sensor (8) and the at least one second temperature sensor (9) are located immediately downstream of the heating module (4).

2. 2. The system according to claim 1, wherein a first temperature sensor (8) for each first heating element (12) and a second temperature sensor (9) for each second heating element (13) are provided.

3. at least one third heating zone (15) disposed adjacent to the at least one second heating zone (11) in a bottom passage zone of the preform, the third heating zone (15) comprising at least one third heating element (16) of the plurality of heating elements; at least one third temperature sensor (17) arranged in the third heating zone outside the heating module (4); 2. The system of claim 1, further comprising: a power supply for supplying power to the at least one third heating element; and wherein the electronic control device is further configured to receive temperature data detected by the at least one third temperature sensor, compare the temperature data with at least one predetermined target temperature of the third heating zone, and act as a feedback by adjusting power of the at least one third heating element.

4. 4. The system according to claim 3, wherein a first temperature sensor (8) is provided for each first heating element (12), a second temperature sensor (9) for each second heating element (13), and a third temperature sensor (17) for each third heating element (16).

5. 5. The system according to claim 1, wherein the plurality of heating elements (12, 13) comprise infrared lamps, NIR lamps or laser lamps arranged along a plane substantially parallel to the plane containing the axis of the preform arranged to traverse the heating module.

6. 6. The system according to claim 1, wherein both the at least one first temperature sensor (8) and the at least one second temperature sensor (9) face the outside of the heating module (4).

7. 4. The system according to claim 3, wherein the at least one third temperature sensor (17) is arranged immediately downstream of the heating module (4), preferably facing the outside of the heating module (4).

8. 1. A furnace (1) for heating plastic material preforms, configured to be positioned upstream of a blow molding machine or a stretch blow molding machine (3), comprising: a plurality of heating systems (2, 2') arranged on at least one bench, each of which comprises a respective heating module (4, 4'), the heating systems being arranged so that a plurality of preforms (5) can traverse the heating systems; each heating module (4, 4') is provided with a plurality of heating elements (12, 13, 16) arranged along a plane substantially parallel to a plane containing an axis of the preform (5) adapted to advance along the at least one bench (31); At least one heating system (2) of the heating systems (2, 2') is provided according to any one of claims 1 to 7, The electronic control device (7) of the at least one heating system (2) comprises: receiving the temperature data detected by both the at least one first temperature sensor (8) and the at least one second temperature sensor (9); comparing the temperature data with predetermined target temperatures of the first heating zone (10) and the second heating zone (11) of the heating module (4); and Acting as a feedback by adjusting the power of the at least one first heating element (12) and the at least one second heating element (13) of the heating module (4) and / or acting as a feedback by adjusting the power of the heating elements (6) of one or more further heating systems (2') of the furnace (1) arranged upstream of the at least one heating system (2) provided according to any one of claims 1 to 7. The furnace (1) is configured to perform the following:

9. the plurality of heating systems (2, 2') including respective heating modules (4, 4') are arranged on a bench (31); a further bench (30) is provided, arranged upstream of said bench (31), equipped with a plurality of heating systems (2'') each equipped with a respective heating module (4'') and connected to said bench (31) by connecting stretches (32); each heating module (4'') is provided with a plurality of heating elements (6') arranged along a plane substantially parallel to the plane containing the axis of the preform (5) advancing along the further bench (30); at least one further first temperature sensor (33), preferably a single further first temperature sensor (33), is arranged in said connecting stretch (32), preferably immediately downstream of said further bench (30); 9. The furnace according to claim 8, wherein a further electronic control device (37) is configured to receive temperature data detected by the at least one further first temperature sensor (33), compare said temperature data with a predetermined target temperature of the surface of the preform at the outlet of the further bench (30), and act as a feedback by adjusting the power of the plurality of heating elements (6′) in one or more of the heating modules (4″).

10. 10. The furnace according to claim 9, wherein the further electronic control device (37) is configured to cooperate with the electronic control device (7) in such a way that the electronic control device (7) can optimize the power of the at least one first heating element (12) and the at least one second heating element (13) of the heating module (4) and / or the power of the plurality of heating elements (6) in one or more of the further heating systems (2') of the bench (31) by transmitting the temperature data detected by the at least one further first temperature sensor (33) to the electronic control device (7).

11. at least one further second temperature sensor (34), preferably a single further second temperature sensor (34) arranged at the inlet of said further bench (30), is provided; 11. The furnace according to claim 9 or 10, wherein the further electronic control device (37) is further configured to receive temperature data detected by the at least one further second temperature sensor (34) and compare the temperature data with a predetermined target temperature of the surface of the preform at the inlet of the further bench (30) to optimize the power of the plurality of heating elements (6') of the heating module (4'').

12. 1. A blow moulding plant for blow moulding plastic material containers, comprising: A furnace (1) according to any one of claims 8 to 11, a blow molding machine or a stretch blow molding machine (3); A blow molding plant comprising:

13. A process for heating plastic material pre-forms using a heating system (2) according to any one of claims 1 to 7, comprising: detecting the temperature of the preform in the first heating zone (10) by the at least one first temperature sensor (8); detecting the temperature of the preform in the at least one second heating zone (11) by the at least one second temperature sensor (9); Including, the temperature data detected by both the at least one first temperature sensor (8) and the at least one second temperature sensor (9) is received by the electronic control device (7), which compares the temperature data with predetermined target temperatures of the first heating zone (10) and the second heating zone (11) and acts as a feedback by adjusting the power of the at least one first heating element (12) and the at least one second heating element (13).

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