Hollow body heating unit for plastic container manufacturing machines

Abstract

The present invention relates to a heating unit (1), which has at least two adjacent emission components (3), each emission component (3) having a stacked body formed by stacking a heat radiation emission area and an area not suitable for emitting heat radiation, characterized in that the emission components (3) are arranged at the same height, along the movement path (T) of the hollow body (2) in the heating unit (1), the heat radiation emission area of ​​the first emission component (3) is followed by the area not suitable for emitting heat radiation of the second emission component (3).

Description

Technical Field

[0001] The field of the invention is that of the design and manufacture of machines for making plastic containers.

[0002] More precisely, the invention relates to a heating unit which allows a plastic hollow body to be heated to or above the glass transition temperature before a container is formed from the hollow body. Background Art

[0003] In order to produce a plastic container from a hollow body, the hollow body must be heated until the plastic material of which it is composed reaches or exceeds the glass transition temperature at which the plastic material can be easily deformed while limiting the risk of breakage of the plastic material.

[0004] In the case of a bottle-shaped container, the hollow body is heated and then introduced into a molding unit where it is generally blown by injecting a pressurized fluid.

[0005] In order to heat the hollow bodies, these are passed in a row into a heating unit and heated in the heating unit by a heating assembly.

[0006] The heating unit usually consists of a plurality of heating assemblies which are juxtaposed to one another to form a heating radiation emitting wall for heating and softening the plastic material of the hollow body.

[0007] The heating assembly carries subassemblies, each of which has an emitting component.

[0008] For example, the emitting component may use laser technology or halogen technology.

[0009] Typically, the heating assembly has a base on which a plurality of emitter subassemblies are mounted one on top of the other.

[0010] The emitting subassemblies each have a support member on which the emitting components are mounted.

[0011] In particular, the emitting element extends over a width which is smaller than the width of the support, so that the technical area is arranged on both sides of the emitting element.

[0012] In other words, these technical areas are formed by a portion of the support that is free of emitting components.

[0013] These technical areas simultaneously allow cooling of the emitting components and also enable them to be connected to an energy source.

[0014] The conventionally known assembly therefore has, along the direction of travel of the hollow body facing it, a series of heat radiation emitting areas which are surrounded by non-heat radiation emitting areas.

[0015] Therefore, on the emission wall, a non-thermal radiation emission column is seen. Therefore, when the hollow body passes in front of the emission wall, it encounters the non-thermal radiation emission area over its entire height.

[0016] These non-thermal radiation emitting columns therefore influence the heating uniformity of the hollow body.

[0017] To compensate for this, the furnace generally has two opposing emitting walls to form a channel in which the hollow body travels.

[0018] The emitting walls may in particular be offset relative to one another so that an emitting region of a first wall is opposite a non-emitting region of a second wall.

[0019] Another technique consists in pivoting the hollow body about itself along its path in the heating unit. This makes it possible to expose a surface that was not exposed to the radiation at a first time to the radiation at a second time.

[0020] While these techniques may improve and homogenize the heating of the hollow body, they are not without drawbacks.

[0021] In fact, the use of two emitting walls increases the energy consumption of the heating unit.

[0022] In addition, the rotation of the hollow body requires a guide mechanism that guides the rotation of the hollow body, for example mechanically, which can be controlled by a computer. Such a guide then requires an expensive and substantial design of the guide components.

[0023] Furthermore, the design and arrangement of the rotation and / or guidance system of the hollow body is still complicated in order to carry out preferential heating, ie heating in which one part of the hollow body is heated more or less than other parts of the same hollow body.

[0024] Finally, in order to obtain uniform heating, it may be useful to heat some parts of the hollow body more strongly, such as the bottom and the part close to the neck of the hollow body. In fact, the central part is the part of the hollow body that is heated the most, which is caused in particular by the heat conduction of the plastic material.

[0025] It may therefore be useful to heat the upper and lower parts more strongly so that the hollow body output from the heating unit has a constant or quasi-constant temperature over its entire height. Summary of the invention

[0026] The present invention is particularly intended to remedy these drawbacks of the prior art.

[0027] More precisely, the invention aims to propose a heating unit that allows obtaining a uniform heating of the hollow body or, conversely, a precise preferential heating of the hollow body.

[0028] The present invention also aims to provide such a heating unit which can extend the service life of the emission subassembly.

[0029] The invention further aims to provide such a heating unit which can be easily maintained and / or replaced.

[0030] These objects and others which will be apparent hereinafter are achieved by means of the present invention, which is directed to a heating unit for heating a series of hollow bodies, having at least two adjacent emission assemblies, each emission assembly having a stack of thermal radiation emission areas and non-thermal radiation emission areas, characterized in that the emission assemblies are arranged at the same height, along the movement path of the hollow bodies in the heating unit, the thermal radiation emission areas of the first emission assembly are followed by the non-thermal radiation emission areas of the second emission assembly. The emission assemblies are adjacent to each other along the movement path of the hollow bodies, the emission areas and non-emitting areas being stacked one on top of another in the height direction, i.e. in a direction transverse to the movement path of the hollow bodies in the heating unit.

[0031] The pattern produced by the emitting and non-emitting areas along the movement path of the hollow body in the heating unit is therefore a kind of checkerboard.

[0032] Depending on the desired type of heating, ie uniform heating or preferential heating, it is possible to have completely alternating arrangements of emitting and non-emitting areas, or for the emitting areas of two adjacent assemblies to at least partially overlap along the path of the hollow body.

[0033] Advantageously, each launch assembly has a plurality of launch subassemblies, each launch subassembly having a support and a launch component, the support having a launch surface, and the launch component being mounted on the launch surface.

[0034] The emission surface is then directed towards the hollow body running in the heating unit, so that an emission wall is formed.

[0035] Therefore, the emitting component is mounted on the emitting surface, for example simply fixed to the emitting surface or embedded therein.

[0036] Preferably, each support has a first height HS, and the emitting component has a second height HE smaller than the first height HS.

[0037] This height difference allows the creation of non-emitting areas which allow the emitting component to be cooled over its entire length.

[0038] In fact, the separation of the emitting components from one another allows them to be cooled simultaneously from the rear, but also from above and below. As a result, the service life of the emitting components is extended.

[0039] According to one embodiment, the emitting section of each emitting subassembly has a specific emitting member.

[0040] This allows for a checkerboard type pattern to be produced and also allows for increased cooling of the emitting components.

[0041] The checkerboard type pattern can also be produced in detail to provide optimal heating uniformity, or conversely to provide the desired precise heating to obtain either hotter or cooler areas on the hollow body.

[0042] Preferably, the emitting member has a plurality of diodes which are arranged in a rod shape.

[0043] Thus, cooling of the components, especially the emitting means, is facilitated as a checkerboard-type pattern is produced.

[0044] Advantageously, for each emitting subassembly, the emitting member is centred on the emitting surface.

[0045] Thus, cooling of the emitting member may be ensured by the support carrying the emitting member, and by the lower subassembly and / or the upper subassembly.

[0046] As a variant, for each emission subassembly, the emission component is located near the lower edge or the upper edge of the emission surface.

[0047] According to this variant, the cooling of the emitting members remains equivalent with respect to the centering of the emitting components on the emitting surface, and the arrangement of the subassemblies is intuitive and easy allowing to produce a checkerboard-type pattern on two adjacent assemblies.

[0048] In practice, on a first assembly, the subassembly may be mounted in a first orientation, whereas on an adjacent subassembly the subassembly is mounted in the opposite orientation, for example pivoted by 180°.

[0049] According to a preferred embodiment, the emitting surface is provided with a heat radiation reflecting coating.

[0050] The reflective coating allows the thermal radiation to be redirected towards the hollow body so as to favour heating of the hollow body, but also avoids heating of the support, thus ensuring cooling of the emitting component.

[0051] Secondly, the present invention relates to a heating unit for heating a series of hollow bodies, which has at least two adjacent emitting components, each emitting component has a stacked body composed of a heat radiation emitting area and an area not suitable for emitting heat radiation, characterized in that the emitting components are arranged at the same height, along the movement path of the hollow body in the heating unit, the heat radiation emitting area of ​​the first emitting component is followed by the area not suitable for emitting heat radiation of the second emitting component.

[0052] Advantageously, the emission assemblies adjoin one another along the movement path of the hollow body, the emission area and the non-emission area being arranged one above the other in height direction, ie in a direction transverse to the movement path of the hollow body in the heating unit.

[0053] The pattern produced by the emission areas and areas not suitable for emitting thermal radiation along the movement path of the hollow body in the heating unit is therefore a kind of checkerboard.

[0054] Depending on the desired type of heating, ie uniform heating or preferential heating, it is possible to have completely alternating emission areas and areas not suitable for emitting thermal radiation, or so that the emission areas of two adjacent assemblies at least partially overlap along the path of the hollow body.

[0055] Advantageously, each launch assembly has a plurality of launch subassemblies, each launch subassembly having a support and a launch component, the support having a launch surface, and the launch component being mounted on the launch surface.

[0056] The emitting surface is then directed towards the hollow body running in the heating unit so as to form an emitting wall.

[0057] Therefore, the emitting component is mounted on the emitting surface, for example simply fixed to the emitting surface or embedded therein.

[0058] Preferably, each support has a first height HS and the emitting element has a second height HE which is smaller than the first height HS.

[0059] This height difference allows the creation of a zone that is not suitable for emitting thermal radiation, which can cool the emitting component over its entire length.

[0060] In fact, the separation of the emitting components from one another allows them to be cooled simultaneously from the rear, but also from above and below. As a result, the service life of the emitting components is extended.

[0061] According to one embodiment, the emitting section of each emitting subassembly has a specific emitting member.

[0062] This allows a checkerboard type pattern to be produced and also allows for increased cooling of the emitting components.

[0063] The checkerboard type pattern can also be produced in detail to provide optimal heating uniformity, or conversely to provide the desired precise heating to obtain either hotter or cooler areas on the hollow body.

[0064] Preferably, the emitting member has a plurality of diodes arranged in a rod shape.

[0065] Thus, cooling of the components, especially the emitting means, is facilitated as a checkerboard-type pattern is produced.

[0066] Advantageously, for each emitting subassembly, the emitting member is centred on the emitting surface.

[0067] Thus, cooling of the emitting member may be ensured by the support carrying the emitting member, and by the lower subassembly and / or the upper subassembly.

[0068] As a variant, for each emission subassembly, the emission component is located near the lower edge or the upper edge of the emission surface.

[0069] According to this variant, the cooling of the emitting member remains equivalent with respect to the centering of the emitting components on the emitting surface, and the arrangement of the subassemblies is intuitive and easy allowing to produce a checkerboard-type pattern on two adjacent assemblies.

[0070] In practice, on a first assembly, the subassembly may be mounted in a first orientation, whereas on an adjacent subassembly the subassembly is mounted in the opposite orientation, for example pivoted by 180°.

[0071] According to a preferred embodiment, the emitting surface is provided with a heat radiation reflecting coating.

[0072] The reflective coating allows the thermal radiation to be redirected towards the hollow body, so as to favour its heating, while also avoiding heating of the support, thus ensuring cooling of the emitting component. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Other features and advantages of the present invention will emerge more clearly from reading the following description of a preferred embodiment of the present invention given as an illustrative but non-limiting example with reference to the accompanying drawings, in which:

[0074] Figure 1 is a schematic top perspective view of a heating unit according to the present invention;

[0075] Figure 2 is a perspective schematic diagram showing one component of a heating unit according to the present invention;

[0076] Figure 3 is a rear perspective schematic diagram of a transmitting subsystem of an assembly according to the present invention;

[0077] Figure 4 is a schematic cross-sectional view of a transmitting subsystem of an assembly according to the present invention according to a first embodiment;

[0078] Figure 5 is a schematic cross-sectional view of a transmitting subsystem of an assembly according to the present invention according to a second embodiment;

[0079] Figure 6 is a schematic cross-sectional view of a transmitting subsystem of an assembly according to the present invention according to a third embodiment;

[0080] Figure 7 is a partial front view schematic diagram of a heating wall of a heating unit according to the present invention;

[0081] Figure 8 is a schematic diagram showing Figure 7 A variation of the heating wall shown. DETAILED DESCRIPTION

[0082] Figure 1 The heating unit 1 according to the invention is shown, which serves to heat a plastic hollow body 2 to or above the glass transition temperature of the plastic material of the hollow body 2 .

[0083] The passage of the hollow bodies 2 in the vicinity of and in the heating unit 1 is carried out as follows. Upstream and downstream of the heating unit 1, the hollow bodies 2 travel in a straight line, i.e. one after the other. The hollow bodies 2 can be arranged in a staggered manner when the hollow bodies pass through the heating unit 1. Thus, the flow of hollow bodies 2 upstream of the heating unit 1 is divided into two streams when entering the heating unit 1 and then reunited to leave the heating unit 1.

[0084] The heating unit 1 consists of a plurality of components 3 which are butted together to form a heating radiation emitting wall.

[0085] More precisely, if Figure 1 As shown, the heating unit 1 has a channel 4 which is formed by two heating radiation-emitting walls and for the plastic hollow body 2 to pass through.

[0086] Reference Figure 2 , a component 3 of the heating unit 1 is shown.

[0087] The assembly 3 comprises a base 5 on which a plurality of emission subassemblies 6 are mounted in parallel.

[0088] More precisely, the emission subassemblies 6 are stacked one on top of the other.

[0089] like Figure 3 As shown, the transmitting subassembly 6 has:

[0090] - support 7;

[0091] - a launching unit 8;

[0092] - Electrical connections 9 for electrically connecting the emission subassembly 6 to a source of electrical energy.

[0093] The electrical connection 9 , for example in the form of a particular cable, engages the support 7 from the rear of the emission subassembly 6 , allowing connection to a source of electrical energy.

[0094] The support 7 has a rear surface 71 for bearing against the base 5 of the assembly and a emitting surface 72 , opposite to the rear surface 71 , for receiving the emitting member 8 .

[0095] The support member 7 also has an upper surface 73 and a lower surface 74 opposite to each other. Figure 2 As shown, when a plurality of emission subassemblies 6 are stacked on top of each other, the upper surface 73 of the first support 7 can receive the lower surface 74 of the second support 7 .

[0096] In addition, the support 7 has an internal pipe network that allows a cooling fluid, such as distilled water, to circulate.

[0097] The emitting component 8 is composed of a specific emitting member, for example, in the form of an emitting rod. In particular, the emitting component 8 is in the form of a laser diode rod.

[0098] More precisely, the emitting component 8 has a plurality of light emitting semiconductor devices, such as vertical cavity surface emitting lasers (VCSELs) (the acronym for Vertical-Cavity Surface-Emitting Laser), which are arranged in parallel to form the emitting rod.

[0099] like Figure 2 and 3 As shown, the emitting element 8 extends over the entire width of the support element 7 .

[0100] In particular, the support has a first width L1 and the emitting member 8 has a second width L2 , the second width L2 being substantially equal to the first width L1 of the support 7 .

[0101] Likewise, the support member 7 has a height HS and the emitting element 8 has a height HE.

[0102] Advantageously, the height HE of the emitting member 8 is less than the height HS of the support 7. For example, the height HE of the emitting member 8 is half the height HS of the support 7.

[0103] Figure 4 , 5 6 show three embodiments of the emission subsystem of the heating unit 1 according to the invention.

[0104] according to Figure 4 In the first embodiment shown, the support element 7 has a groove 75 for receiving the emitting element 8 .

[0105] More precisely, the groove 75 is opened in the emission surface 72 of the support 7 in the direction of the rear surface 71 .

[0106] like Figure 4 As shown, when the emitting component 8 is connected to the supporting member 7 , the emitting component is assembled in the groove 75 and is flush with the emitting surface 72 of the supporting member 7 .

[0107] Advantageously, the slot 75 is positioned centrally on the emitting surface 72 of the support 7. Thus, the emitting member 8 is housed in the support 7, which has an upper portion 76 and a lower portion 77 respectively located above and below the emitting member 8.

[0108] According to this embodiment, the support 7 can dissipate the heat generated by the emitting component 8 to the outside of the assembly 3 or to the base 5 of the assembly 3 by means of the upper part 76 and the lower part 77. This heat transfer is carried out in particular by heat conduction inside the support 7 and by heat absorption by the cooling fluid.

[0109] according to Figure 5 The second embodiment shown and Figure 6 In the third embodiment shown, the emitting member 8 is directly mounted on the emitting surface 72 of the support 7 , and the support 7 does not have the groove 75 .

[0110] Therefore, the emitting member 8 is supported by the support 7 only via the emitting surface 72 of the support 7 .

[0111] Thus, when the emitting element 8 emits heating radiation, the heat dissipated by the emitting element 8 can be discharged by the emitting surface 72 more easily than it can be dissipated in a volume having a height greater than the height of the emitting element 8 alone.

[0112] According to a second embodiment, the emission means 8 are located in the middle of the emission surface 72 of the support 7 .

[0113] More specifically, the emitting member 8 is located at a height h1 and h2 from the upper surface 73 and the lower surface 74 of the supporting member 7, respectively.

[0114] In other words, the heights h1 and h2 are equal to each other.

[0115] according to Figure 6 In the third embodiment shown, the emitting member 8 is located near the lower edge or the upper edge of the emitting surface 72 .

[0116] In other words, the emitting member 8 is located near the upper surface 73 or the lower surface 74 of the support 7 .

[0117] More precisely, if Figure 6 As shown, the emitting component 8 is located near the lower surface 74 of the supporting member 7 and is separated from the upper surface 73 by a height h3 , which is equal to or approximately equal to two-thirds of the height HS of the supporting member 7 .

[0118] Therefore, when the emitting component 8 is working, ie emitting heat radiation, advantageously, the heat generated by the emitting component 8 is discharged toward the upper surface 73 of the support 7 through heat conduction between the support 7 and the emitting component 8 .

[0119] Reference Figure 7 , partially showing the launch wall. The launch wall is composed or formed by a plurality of components 3 connected side by side.

[0120] like Figure 2 and 7 As shown, a spacing height 10 is produced between two transmitting elements 8 arranged one above the other.

[0121] This spacing height 10 allows the heat emitted by the emitting element 8 to be dissipated.

[0122] Advantageously, the spacing height 10 is equal to the height of the emitting member 8 .

[0123] like Figure 2 , 7 As shown in FIG. 8 and / or FIG. 9 , the assembly 3 thus has a vertical pattern, which is formed by alternating emission areas 11, i.e., areas formed by the emission components 8, and non-emission areas 12, i.e., areas formed by the spacing heights 10. In other words, the so-called “non-emission area 12” refers to an area that is not suitable for emitting thermal radiation.

[0124] Reference Figure 7 , these transmitting components 3 are arranged to form a checkerboard.

[0125] More precisely, along the movement path T of the hollow body 2 in the heating unit 1 , a spacing height 10 of a first component 3 is followed by an emission region 11 of an adjacent second component 3 .

[0126] Advantageously, this checkerboard-type pattern is repeated over the entire wall of the heating unit 1 or on each wall of the heating unit 1 .

[0127] This checkerboard-type pattern allows, along the path T of the hollow body 2 in the heating unit 1 , the removal of vertical areas not suitable for emitting thermal radiation, ie areas 12 not suitable for emitting thermal radiation over the entire height of the assembly 3 .

[0128] In practice, the area 12 not suitable for emitting thermal radiation, i.e. the spacing height 10, extends parallel to the path T of the hollow body 2 and is small enough so that the heat conduction in the material allows a substantially uniform heating to be produced over the entire periphery of the hollow body 2. In addition, in order to obtain a completely uniform heating, it is possible to combine a checkerboard pattern with a rotation of the hollow body 2 as it passes through the heating unit 1.

[0129] Advantageously, the width of a module 3 is equal to the peripheral development of the hollow body 2. However, this value can be adjusted according to the rotation speed of the hollow body 2, it being understood that the entire periphery of the hollow body 2 is irradiated by the same module as it moves.

[0130] In other words, for the same component 3, the hollow body 2 is exposed to an equal emission time at every point of its periphery.

[0131] Likewise, the number of assemblies 3 per wall is advantageously even. Considering the heating radiation emitting wall, the rotation speed of the hollow body 2 (for example five revolutions per second), which varies according to the width of the assembly 3 on each wall of the heating unit 1, allows to achieve a completely uniform heating of the hollow body 2, since, over the periphery of the hollow body 2, each point of the hollow body 2 receives the same irradiation exposed to the radiation of the emitting means 8.

[0132] In other words, according to Figure 7 , the heating of the hollow body 2 is uniform from the perspective of the heating unit 1 .

[0133] Conversely, taking the hollow body 2 into account, heating uniformity can be achieved by means of preferential heating of the hollow body 2 .

[0134] Reference Figure 8 The uniformity of the heating of the hollow body 2 results from the fact that a portion of the hollow body 2 along the height of the hollow body is over-irradiated and / or under-irradiated.

[0135] In fact, in the central part of the hollow body 2 , the heat is generally higher than at its ends (at its neck and its bottom), even if the amount of heating radiation to which the hollow body is subjected is the same at every point of the hollow body 2 .

[0136] This is explained in particular by the temperature expansion in the plastic material of the hollow body 2 due to heat convection.

[0137] Therefore, the central part receives heat from the ends in addition to heat from thermal radiation, and the thermal curve along the height of the hollow body 2 can be Gaussian (at its height, the ends of the preform are cooler than the center of the preform).

[0138] To compensate for this, provision can be made for the ends of the hollow body 2 to be overheated.

[0139] This overheating can be achieved by increasing the power of the heat radiation emitted by the emitting member 8 to the end region, or by overlapping the emitting regions 11 of two adjacent components 3, such as Figure 8 shown.

[0140] In fact, the overlap of two adjacent emission areas results in a prolonged exposure of the hollow body 2 to the thermal radiation, thereby intensifying the heating of the plastic material.

[0141] Thus, by simply overlapping the emission areas of two adjacent components 3, the end of the hollow body 2 can be overheated. The convection of heat in the hollow body 2 can maintain uniform heating when output from the heating unit 1.

[0142] According to a preferred embodiment, the emitting surface 72 of the support 7 is coated with a thermal radiation reflecting coating.

[0143] According to another embodiment, the region 12 which is not suitable for emitting thermal radiation can be covered with a thermal radiation reflecting coating.

[0144] As an illustrative example, the reflective coating is a thin layer of gold.

[0145] In particular, the gold layer can reflect the laser radiation of the emitting element 8 without the carrier 7 being overheated.

[0146] The presence of a spacing height 10 above and / or below the emitting element 8 can provide the emitting element 8 with a longer service life by means of better cooling.

[0147] In fact, the emitting element 8 is cooled simultaneously from above, from below and from the rear, in contrast to the prior art, in which the emitting element 8 was cooled only from the side and from the rear.

[0148] Therefore, in the heating unit 1 according to the invention, the heat exchange area between the emitting member 8 and the support 7 is larger than in the heating unit according to the prior art.

[0149] According to an alternative embodiment not shown, the assembly 3 has no base 5 but merely comprises a stack of emission subassemblies 6 stacked together.

[0150] In this case, a plate common to all emission subassemblies 3 is arranged in the heating unit 1, forming a base on which all emission subassemblies 6 are fixed.

Claims

1. A heating unit (1) for heating a series of hollow bodies, comprising at least two adjacent emission assemblies, each emission assembly comprising a stack of a heat radiation emission area (11) and an area (12) not suitable for emitting heat radiation, characterized in that: The emission components are arranged such that, at the same height, along the moving path (T) of the hollow body (2) in the heating unit (1), the heat radiation emission area (11) of the first emission component is followed by the area (12) of the second emission component that is not suitable for emitting heat radiation; and the width of an emission component is equal to the peripheral expansion size of the hollow body (2).

2. The heating unit (1) according to claim 1, characterized in that Each emitting assembly has a plurality of emitting subassemblies (6), each emitting subassembly has a support (7) and an emitting component (8), the support has an emitting surface (72), and the emitting component is mounted on the emitting surface (72).

3. The heating unit (1) according to claim 2, characterized in that: Each support member (7) has a first height (HS), and the emitting element (8) has a second height (HE) which is smaller than the first height (HS).

4. The heating unit (1) according to claim 2 or 3, characterized in that: The emitting component (8) of each emitting subassembly (6) has an emitting member.

5. The heating unit (1) according to claim 4, characterized in that The emitting member has a plurality of diodes arranged in a rod shape.

6. The heating unit (1) according to claim 2, characterized in that For each emitting subassembly (6), the emitting component (8) is centered on the emitting surface (72).

7. The heating unit (1) according to claim 2, characterized in that For each emitting subassembly (6), the emitting component (8) is located near the lower edge or the upper edge of the emitting surface (72).

8. The heating unit (1) according to claim 2, characterized in that The emitting surface (72) is provided with a thermal radiation reflecting coating.

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