Device for heating plastic particles and device for producing plastic containers

Abstract

The utility model relates to a device (1) for heating plastic parisons (10) and to a device for producing plastic containers, the device (1) for heating plastic parisons (10) having a transport device (2) which transports plastic parisons along a predefined transport path (T), the transport device having a rotating transport means (20), the utility model relates to a device (1) for heating plastic parisons (10), comprising a transport means (22) on which a plurality of holding devices (22) for holding the plastic parisons (10) to be heated are arranged, characterized in that the device (1) has an inspection device (4) which is suitable and intended to inspect the holding devices (22) that are not equipped with plastic parisons.

Description

Technical Field

[0001] The utility model relates to a heating device, in particular to a device for heating a plastic preform and a device for producing a plastic container. Background Art

[0002] It is known in the prior art that plastic preforms are first heated in an oven and then expanded into plastic containers, in particular plastic bottles, by means of a blow molding machine, in particular a stretch blow molding machine. Various ovens are known for this purpose. For example, infrared ovens are known that have a conveyor device, such as a conveyor chain, which conveys the plastic preforms to be heated through a heating tunnel. For this purpose, holding devices are provided for holding the plastic preforms, which in turn are arranged on the conveyor chain.

[0003] In a special design, a heating mandrel (also called a holding mandrel) is provided, on which the plastic preform is suspended. Such ovens have a plurality of such holding devices, in particular heating mandrels. Thus, for example, 160 to 500 such heating mandrels can be provided in such ovens, which hold the plastic preform during the heating process. Since the heating mandrel with the plastic preform partially rotates, the concentricity must be maintained as accurately as possible. However, collisions or improper modifications can cause these mandrels to bend, which can lead to uneven movement of the plastic preform.

[0004] Since the heating mandrel no longer runs completely cleanly and smoothly, the plastic parison can be heated unevenly. This is particularly noticeable with very light plastic parisons and can cause the container to be blown unevenly or even cracked.

[0005] Even in the case of so-called preferential heating, ie the plastic preform is heated unevenly over its circumference, this can significantly disrupt the temperature distribution on the plastic preform. Utility Model Content

[0006] The object of the invention is therefore to improve the transport of plastic preforms and to achieve more uniform heating. According to the invention, this object is achieved by the subject matter of the independent patent claims. Advantageous embodiments and improvements are the subject matter of the dependent claims.

[0007] The device for heating plastic preforms according to the utility model has a conveying device, which conveys the plastic preforms along a predetermined conveying path. The conveying device has a rotating conveying tool, on which a plurality of holding devices for holding the plastic preforms to be heated are arranged.

[0008] According to the invention, the device has an inspection device which is suitable and intended for inspecting a holding device which is not provided with a plastic preform.

[0009] It is therefore proposed that a check is preferably carried out inside the oven, by which in particular the position and / or the orientation of the holding device is to be determined. Advantageously, the device has at least one heating device and preferably a plurality of heating devices.

[0010] These heating devices can be, for example, heating boxes arranged along the conveying path of the plastic preform. Particularly preferably, these heating devices are fixedly arranged. Here, they are particularly so-called heating boxes.

[0011] Particularly preferably, the heating devices each have irradiation devices, such as halogen lamps or the like, which apply infrared radiation to the plastic preforms.

[0012] Particularly preferably, these heating devices are arranged on one side of the conveying path. Particularly preferably, reflector devices reflecting the thermal radiation are arranged on the opposite side. In this way, the device has at least one heating channel through which the plastic preforms are conveyed.

[0013] Preferably, the at least one heating channel is designed so that the plastic preforms can be conveyed through the heating channel individually and preferably in a single row. Preferably, the width of the heating channel is less than six times the base diameter of the plastic preforms, preferably less than five times the diameter, preferably less than four times the diameter.

[0014] Preferably, the radiation which heats the plastic preform is infrared radiation.

[0015] In a preferred embodiment, the conveying means is a conveyor belt or a conveyor chain. In addition, a shielding device is preferably provided, which realizes heat shielding of the mouth of the plastic preform. Each holding device can have such a heat shielding plate.

[0016] In a preferred embodiment, the holding device can transport the plastic preforms individually. Particularly preferably, the holding device, in particular the holding device in which the plastic preforms are arranged, can be rotated about its longitudinal axis. In this way, the plastic preforms are also rotated about their longitudinal direction, in particular during their heating. In this way, uniform heating of the plastic preforms in their circumferential direction is achieved.

[0017] In a preferred embodiment, the conveying path of the plastic preforms has at least one, preferably two straight sections. Preferably, these straight sections are connected by a deflection area, in which the movement direction of the plastic preforms is reversed.

[0018] Particularly preferably, the inspection device has an image recording device which is suitable and intended to record a spatially resolved image of the holding device. Preferably, the inspection device is suitable and intended to inspect the holding device in a contactless manner.

[0019] Preferably, a comparison device is provided which compares the recorded image with a reference image, in particular in order to determine whether the holding device is arranged and / or extends centrally or eccentrically.

[0020] Here, the image recording device can record the image of the holding device to determine whether there is eccentricity. However, two images of the holding device in different rotational positions (for example, two images of the holding device rotated 180°) can also be recorded to more easily determine the eccentricity.

[0021] In order to assess the eccentricity, reference can be made to a specific reference point in the image (for example a reference point on a hexagonal screw), which reference point can be located in the center of the holding device.

[0022] Particularly preferably, the holding device has an annular flexible element, for example in the form of an O-ring.

[0023] In a preferred embodiment, the inspection device, in particular the image recording device, is arranged below the holding device. Therefore, it is particularly preferred that the image recording device records images in a vertically upward direction or is oriented in this direction.

[0024] Particularly preferably, the distance between the inspection device and the holding device is greater than 8 cm, preferably greater than 10 cm, particularly preferably greater than 12 cm. Particularly preferably, the distance between the inspection device and the holding device is less than 30 cm, preferably less than 20 cm.

[0025] In another preferred embodiment, the inspection device can be moved and / or adjusted in the longitudinal direction of the plastic preform. In this way, the same inspection device can be used more easily to inspect the holding device and (particularly in working operation) the plastic preform.

[0026] Preferably, the holding device is checked in a state control operation and the plastic preforms are checked in a production operation, wherein the state control operation is different from the production operation. Compared with the production operation, in the state control operation, for example, there are no preforms in the heating device and the heating device may be operated at a reduced conveying speed.

[0027] Thus, during production or production operation, the inspection device is preferably used to inspect the plastic preforms, while in the state control operation the same inspection device is used to inspect the holding device. In this case, the inspection device can preferably be designed to be movable in the direction of the holding device. This movement of the holding device can preferably be automated, wherein the positions can be stored in a recipe.

[0028] In another advantageous embodiment, the holding device is a holding projection and preferably a holding mandrel, which can be introduced into the mouth of the plastic preform to hold the mouth. Particularly preferably, the holding device has a clamping tool, which is suitable and intended for holding the plastic preform on the holding device.

[0029] The holding device is preferably a heating mandrel or a gripping device. The heating mandrel can preferably be introduced into the mouth of the plastic preform. In contrast, the gripping device preferably consists of at least two gripping elements that can be moved relative to each other and grip the plastic preform on the periphery, preferably above or below the support ring.

[0030] Preferably, the empty mandrel or the holding device (ie not occupied by a plastic preform) is recorded from below by means of a camera and the contour or surface of the mandrel and / or the holding device is preferably checked for concentricity relative to a reference position.

[0031] This operation can be carried out, for example, during production breaks or when starting up a machine, so that the availability of the device remains unaffected.

[0032] For example, existing hardware can be used as a camera, or additional hardware can be installed. For example, a camera that is also used for gate inspection can be used, or a camera for mouth recognition in the preferential heating (PH) process can also be used.

[0033] In addition, a camera can be used which is aimed from below at the conveyor or oven chain.

[0034] In a further preferred embodiment, the checking device is therefore suitable and intended to detect the concentricity of the holding device. Particularly preferably, the checking device is also suitable and intended to detect a measured value of the eccentricity.

[0035] The checking device is preferably suitable for detecting a characteristic value of the concentricity of the holding device. The measured characteristic value is then preferably compared with a target value, wherein a signal and / or a recommendation for action is output if the characteristic value deviates from the target value. The target value can preferably be a fixed value, but can also be a limited range. It is conceivable, for example, that the deviation from the target value is within ±2 mm, preferably within ±1.5 mm and particularly preferably within ±1 mm.

[0036] It is also preferably conceivable to readjust the maintenance intervals based on the information obtained (cloud; big data). The obtained data are collected and stored in a storage device, for example. New maintenance intervals are preferably calculated based on the obtained data, wherein the obtained data and the new maintenance intervals can also be shared with other machines via the cloud. These data can also preferably be used for statistical evaluations (for example to determine how deviations change).

[0037] In a further advantageous embodiment, the inspection device is arranged in the turning region of the conveyor, in which the direction of movement of the plastic preforms is reversed. The arrangement in this region has the advantage that the holding devices are spaced further apart from one another in this region than in the corresponding straight sections. Alternatively, the inspection device can be arranged in the inlet region of the device, in which the plastic preforms are introduced into the heating process.

[0038] It is also possible that an inspection device, for example in the form of a camera, is located at the location of the heating unit, for example at the location of an unequipped heating box. In this embodiment, the inspection device will be arranged in the oven itself, preferably in the center of the oven. The background to this is the conceivable option of placing a camera recognition device for the support ring marking in a preferential heating machine between the normal heating zone and the preferential heating zone (for example approximately in the middle of the back of the oven). This camera can be used at the same time to inspect the mandrel.

[0039] In a further advantageous embodiment, the device has an assignment device which assigns the images recorded by the image recording device to a specific holding device in an exact one-to-one manner.

[0040] For example, it can thus be determined that a specific image corresponds to a holding device 70. Ideally, the number of the identified mandrel or the identified holding device is therefore known to the device. In this way, this number can be reported to the user. By measuring the deflection of the holding device or the mandrel, it is preferably also conceivable to divide the concentricity into more or less critical deviations. In the case of strong reflections on metals, a coating of the clamp can be conceivable, but as described in detail below, the corresponding area is preferably not in contact with the plastic preform.

[0041] Therefore, the holding device preferably has a coating to improve the image recording. Particularly preferably, the holding device has a coating in its area that is inspected and / or observed by the image recording device. Particularly preferably, the holding device has an end face coating. This coating can be, for example, an antireflection coating. However, it can also be a highly reflective coating in reverse.

[0042] Particularly preferably, the coating is a matte coating, in particular on the bottom side. Particularly preferably, the coating does not come into contact with the plastic preform.

[0043] In another preferred embodiment, the holding device has a marking, in particular in an area that can be detected by the image recording device. The concentricity can be checked more easily with reference to the marking.

[0044] The inspection device is preferably suitable and intended for carrying out an inspection using a reflected light method.

[0045] Particularly preferably, a lighting device is provided, which illuminates the holding device, in particular for the purpose of recording an image. The lighting device is preferably a flashlight.

[0046] The utility model also relates to a method for heating a plastic preform, wherein a conveying device conveys the plastic preform along a predetermined conveying path, and wherein the conveying device has a rotating conveying tool, on which a plurality of holding devices for holding the plastic preform to be heated are arranged.

[0047] According to the invention, a checking device is provided which checks the holding device without any plastic preforms and preferably outputs a value which characterizes the concentricity of the holding device, in particular relative to a reference position.

[0048] For example, the inspection device can record and / or output an image of the holding device, from which the concentricity or eccentricity can be derived.

[0049] The inspection is preferably carried out during the movement of the plastic preforms at a reduced conveying speed compared to the working operation. In this case, the inspection device can record images of the holding devices while they are moving, but it is also possible to stop the individual holding devices in order to be able to record the images. It is also possible to stop the holding device and rotate it about its own axis, so that a plurality of images (at different rotational positions) can be recorded in order to be able to better determine the eccentricity.

[0050] Particularly preferably, the images of the holding devices are recorded and these images are associated with the respective holding devices. For example, a specific image can be associated with a mandrel 70 or a holding device. The assignment and the images are preferably saved.

[0051] Particularly preferably, the device monitors itself. In this case, the device can monitor itself permanently. In this case, a bent retaining device can be quickly detected and reported to the user. By assigning a number to the mandrel or retaining device, further troubleshooting can be omitted. The retaining device can then be observed, oriented or replaced.

[0052] By measuring the change, the device determines whether the spare part needs to be installed or replaced immediately or at the next maintenance interval. In the preferred method, the existing inspection device or camera is used, so that the manufacturer needs little or no subsequent installation hardware. This makes retrofitting easier.

[0053] In addition, the utility model also relates to an apparatus for producing plastic containers, which has a molding device, which has a blow molding wheel with a plurality of molding stations, wherein each molding station has: a blow molding mold, in which a plastic preform is molded into a plastic container; and at least one processing element for processing and in particular molding the plastic preform.

[0054] According to the invention, the apparatus has an inspection device which is suitable and intended for inspecting at least one processing element of the forming station.

[0055] Therefore, it is also proposed that the device for producing plastic containers has an inspection device as described above. Preferably, both the device for heating plastic preforms and the device for producing plastic containers have such an inspection device.

[0056] In a preferred embodiment, the at least one handling element is selected from the group of handling elements comprising a horizontal bar, a blow molding nozzle, a blow molding mold, a bottom mold, and the like.

[0057] In another preferred embodiment, the inspection device inspects the processing element in the open state of the blow mold. In particular, the side of the blow mold is in the open state. Therefore, preferably, the inspection of at least one processing element is performed when there is no plastic parison or plastic container in the blow mold.

[0058] The checking device is preferably suitable for and intended to determine a value characterizing the condition of the processing element. It may for example be a value from which it can be deduced whether for example a horizontal rod is bent.

[0059] The checking device is preferably suitable for and intended to determine a value characterizing the type of the processing element. It may for example be a value from which it can be deduced whether the correct horizontal rod is installed.

[0060] Particularly preferably, the checking device is suitable and intended to determine a value which characterizes the condition of the processing element and the type of the processing element. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Further advantages and embodiments are apparent from the accompanying drawings.

[0062] Figure 1 A schematic diagram of a device according to the utility model is shown;

[0063] Figure 2 A diagram of a holding device is shown;

[0064] Figure 3a a diagram showing a recorded image of the correct holding device; and

[0065] Figure 3b A diagram showing a recorded image of a faulty holding device. DETAILED DESCRIPTION

[0066] Figure 1 A schematic diagram of a device 1 for heating a plastic preform 1 according to the present invention is shown.

[0067] The apparatus has a separation device (such as a single-circulation star wheel 30 ) which separates the plastic preforms fed in rows through a feeding device 17 and conveys the separated plastic preforms 10 to a conveying device 2 .

[0068] The conveying device 2 conveys the plastic preforms 10 along a conveying path T. The conveying path T has two straight sections which are connected by a deflection region.

[0069] Reference numeral 20 denotes a rotating conveying tool, in particular a conveying chain, for example. A plurality of holding devices 22 for holding plastic preforms are arranged on the conveying tool.

[0070] Reference numeral 24 denotes a heating device, such as a heating box, which is arranged stationarily along the conveying path T. The heating device has a plurality of radiant heaters 26 which preferably extend along the conveying path T, wherein a plurality of radiant heaters 22 are preferably arranged one above the other in the longitudinal direction of the plastic preforms to be heated.

[0071] Reference numeral 12 designates a further conveying device which conveys away the heated plastic preforms 10 .

[0072] Reference numeral 4 denotes an inspection device for inspecting holding devices 22 that are not occupied by plastic preforms. This can be done, for example, outside the operating state of the device 1, during which no plastic preforms are arranged on the holding devices 22. The inspection device 4 preferably has an image recording device that records an image of the holding devices 22. The image recording device is in particular a camera.

[0073] The inspection device shown here is located in the deflection region of the transport path T, in which the direction of movement of the plastic preforms is reversed.

[0074] For this purpose, the image recording device 42 is preferably arranged below the holding device.However, the image recording device can also be arranged laterally beside the transport path T and can use deflection means, such as mirrors, for image recording.

[0075] Furthermore, the device 1 preferably has an allocation device (not shown) which respectively assigns those holding devices 22 on which an image has been recorded to the recorded image.

[0076] Figure 2 A diagram of a holding device 22 is shown. It has a (lower) end face 32, which is preferably inspected by an inspection device. Reference numeral 52 denotes a fastening tool, which preferably secures the individual elements of the holding device to each other.

[0077] When plastic preforms are conveyed, the lower area of ​​the holding device 22 enters the mouth of these plastic preforms. Reference numeral 36 denotes a clamping tool for holding the plastic preforms, such as a radially outwardly pushed protrusion. Reference numeral 34 denotes a flexible annular element, such as an O-ring.

[0078] Figure 3a and Figure 3b Two recorded images of the holding device are shown. In each case, the fastening tool 52 located in the center of the holding device 22 can be seen again. Reference numeral 54 denotes an end face, which is particularly used for observation or inspection. This end face can have a special coating to make observation or image evaluation easier.

[0079] Reference numeral 56 denotes the outer wall of the holding device. The outer wall 56, the tightening tool 52 and the end face 54 are preferably concentric with each other. Therefore, these elements can be used to detect concentricity or determine eccentricity.

[0080] Reference numeral 58 denotes a shielding plate, which is used to prevent the mouth of the plastic preform from being overheated. An annular gap 57 is formed between the shielding device 58 and the outer wall.

[0081] Figure 3a The correct holding device is shown. It can be seen that the fastening tool, the end face 45 and the outer wall 56 are concentric with the annular gap. Therefore, the holding device is aligned concentrically here and is therefore correct.

[0082] Figure 3b The holding device 22 shown is eccentric. Here, the end face of the holding device 22 is slightly offset to the left compared to its target position. Figure 3b The holding device 22 is shown to be defective.

[0083] Preferably, Figure 3a and Figure 3b The image recorded in the image is compared with a reference image, which can, for example, show a correct holding device.

[0084] The device 1 preferably also has an evaluation device which is suitable and intended to evaluate the recorded images. Therein, the evaluation device is preferably also suitable and intended to output a value characterizing a certain eccentricity.

[0085] Here, the value can be assigned to a specific holding device. Depending on the value, different measures can preferably be initiated.

[0086] The applicant reserves the right to claim all features disclosed in the application documents that are essential to the utility model, as long as these features are novel compared to the prior art individually or in combination. Further, it is to be noted that features that can be advantageous in themselves are also described in individual drawings. A person skilled in the art will immediately recognize that a certain feature described in a drawing can be advantageous even without using other features in the drawing. In addition, a person skilled in the art will recognize that advantages can also be obtained by combining several features shown in a single drawing or in different drawings.

Claims

1. A device for heating plastic preforms, comprising a conveying device (2) for conveying the plastic preforms along a predetermined conveying path (T), wherein: The conveying device has a rotating conveying tool (20) on which a plurality of holding devices (22) for holding the plastic preforms (10) to be heated are arranged. It is characterized in that The device (1) has an inspection device (4) which is suitable and intended for inspecting the holding device (22) which is not provided with a plastic preform.

2. The device for heating a plastic preform according to claim 1, It is characterized in that The inspection device (4) has an image recording device (42) which is suitable and intended to record a spatially resolved image of the holding device (22).

3. The device for heating a plastic preform according to claim 2, It is characterized in that The image recording device (42) is arranged below the holding device.

4. The device for heating a plastic preform according to claim 1, It is characterized in that The holding device is a holding mandrel which can be introduced into the mouth of the plastic preform.

5. The device for heating a plastic preform according to claim 1, It is characterized in that The inspection device (4) is suitable for detecting a concentricity characteristic value of the holding device.

6. The device for heating a plastic preform according to claim 1, It is characterized in that The inspection device (4) is arranged in a deflection region of the conveying device, in which the direction of movement of the plastic preforms is reversed.

7. The device for heating a plastic preform according to claim 1, It is characterized in that The device (1) has an assignment device which accurately associates the image recorded by the inspection device (4) with a specific holding device (22).

8. The device for heating a plastic preform according to claim 1, It is characterized in that The holding device has a coating to improve image recording.

9. A device for producing plastic containers, comprising a forming device having a blow moulding wheel with a plurality of forming stations, wherein each of the forming stations comprises: a blow mould in which a plastic parison (10) is formed into the plastic container; and at least one processing element for processing, It is characterized in that The apparatus has an inspection device which is suitable and intended for inspecting the at least one processing element of the forming station.

10. The apparatus for producing plastic containers according to claim 9, It is characterized in that The at least one handling element is selected from a group of handling elements comprising a horizontal rod, a blow molding nozzle, a blow molding mold, and a bottom mold.

11. The apparatus for producing plastic containers according to claim 9, It is characterized in that The inspection device inspects the processing element in a state where the blow mold is opened.

12. The apparatus for producing plastic containers according to claim 9, It is characterized in that The checking device is suitable and intended to determine a value characterizing the condition of the processing element.

13. The apparatus for producing plastic containers according to claim 9, It is characterized in that The checking device is suitable and intended to determine a value characterizing the type of the processing element.

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