Method and apparatus for inspecting a container comprising blown-in dust

Abstract

The invention relates to a method for inspecting a container (10), comprising the following steps: - providing an unfilled container (10); - introducing a powdery substance into the interior of the container; - optically inspecting the container by means of an inspection device (6).

Description

[0001] manual

[0002] The present invention relates to a method and apparatus for inspecting containers, particularly plastic preforms, especially transparent plastic preforms.

[0003] It is known from the prior art that a plastic material preform is heated and, in this heated state, supplied to expand from the blow molding machine to form a plastic bottle. In this case, it is also known that this type of plastic material preform is transparent, and typically transparent plastic material preforms and other containers are generally inspected using optical methods, which are designed to detect residues, foreign substances, etc., that are visually distinguishable from the background or transparent substrate material.

[0004] Other characteristics (such as size, quantity, material, and these foreign substances) play an important role in how this type of foreign substance can be identified.

[0005] In part, the prior art has the disadvantage that liquids or highly viscous transparent foreign substances, or at least partially transparent foreign substances, are almost entirely undetectable or completely undetectable. Typical examples are oily or aqueous impurities with particulate binding and sticky properties. Therefore, the object of the present invention is to improve the possibility of inspecting such containers. This is achieved according to the invention through the subject matter of the independent claims. Advantageous embodiments and improvements are the subject matter of the dependent claims.

[0006] In the method for inspecting containers according to the invention, initially unfilled containers are provided. A powdered substance is introduced into these unfilled containers, entering the interior of the container. This is followed by optical inspection of the containers using an inspection device.

[0007] Therefore, the present invention assumes that at least one inspection of the powdered substance is possible, particularly when the powdered substance remains adhered to the inner wall of the container (such as a plastic preform). In this way, it can be inferred that there is a corresponding free-flowing substance or a normally undesirable substance within the container.

[0008] The supply of powdery substances or dust with certain properties leads to increased particle formation in contaminated areas of the container, and these areas are optically more distinguishable from adjacent areas. In particular, this particle formation can be identified on the walls of the container, and especially on those walls that subsequently expand.

[0009] In the preferred method, the volume of the substance introduced into the container is less than 40% of the container's interior, preferably less than 30%, preferably less than 20%, preferably less than 10%, and preferably less than 5% of the interior space. This means that only a very small amount of powdery substance is introduced compared to the interior of the container.

[0010] Therefore, the powdered substance is not, in particular, the filling material for the container to be filled, but rather a test substance, which is preferably removed from the container at least partially again or discharged together with the container into which the test substance was introduced.

[0011] It is possible to perform manual testing using the human eye. However, the idea here is to propose an automated inspection method, in which the possible processes are conceivable.

[0012] Therefore, in a preferred embodiment, the conveying device delivers the container to the insertion station, which introduces the powdered material into the container, and / or the conveying device delivers the container with the powdered material to the inspection equipment.

[0013] In this case, multiple conveying devices can also be set up, which transport containers in various conveying sections. Thus, for example, the first conveying device that transports the containers to the insertion station can be selected from a group of conveying devices including chain conveyors, sorting rollers, conveyor rails, conveyor stars, conveyor trays, linear motor conveyors, etc. Preferably, this conveying device transports the selected containers, particularly preforms made of plastic material.

[0014] Another conveying device can transport containers from the insertion station to the inspection device. This conveying device can also be selected from a set of conveying devices, which includes chain conveyors, sorting rollers, conveyor rails, conveyor stars, conveyor trays, linear motor conveyors, etc.

[0015] The conveying device may have gripping elements for grasping the container. In a preferred embodiment, the insertion station moves with the container during container conveying. For example, the insertion station may be arranged on a movable and, in particular, rotatable carrier. It is also conceivable to arrange multiple such insertion stations on such a movable carrier.

[0016] Preferably, the container is further conveyed by the inspection device via a conveying device. This conveying device, and possibly another conveying device, may be selected from a set of conveying devices, including chain conveyors, sorting rollers, conveyor rails, conveyor stars, conveyor trays, linear motor conveyors, etc.

[0017] However, the insertion stations can also be arranged in a fixed manner along the container's transport path, and the container is transported through the insertion station.

[0018] In another preferred method, the inspection device examines the container wall for any powdery substance adhering to it. As mentioned above, this can serve as an indication of the presence of materials that are not visible in the container, but this results in the powdery substance adhering to it. Therefore, the presence of this powdery substance on the container wall can be used to infer that an (undesired) substance is present in these containers.

[0019] In the preferred method, the container is a plastic container. However, the method described herein can also be applied to other materials. Therefore, the container can also be a glass container.

[0020] In another preferred method, the container is a prefabricated plastic component.

[0021] Particularly preferably, the container is made of a material that is at least partially, and preferably completely, transparent, especially a material that is transparent to light in the visible spectrum.

[0022] In another preferred embodiment, the powdered material is injected into the interior of the container. This achieves distribution of the material within the container and, preferably, also ensures uniform adhesion to the inner wall of the container.

[0023] Preferably, the injection nozzle and return pipe are placed on the container opening in a shape-fit or sealed manner.

[0024] Particularly preferably, the test dust is rinsed with sufficient energy in the absence of the described adhesion, such that preferably no or only minimal test dust remains in the container.

[0025] In another preferred embodiment, the powdered substance is corundum or a substance containing corundum. Corundum is characterized by its extremely high hardness.

[0026] In another preferred method, the powder has a particle size of at least 10 μm, preferably at least 30 μm, and more preferably at least 50 μm. In another preferred embodiment, the powder has a particle size of less than 400 μm, preferably less than 300 μm, more preferably less than 200 μm, and particularly preferably less than 150 μm. This particle size has proven advantageous for easy adhesion to the inner wall of a plastic container.

[0027] In another preferred embodiment, the powdered substance is food-compatible. This is important because even in another method, the possibility of small residues of the substance remaining in the container cannot be ruled out.

[0028] In another preferred method, the container containing the powdery material is separated or cleaned. For example, the powdery material or test dust may be blown into a portion of the container that must be discarded after automated optical inspection, because even in the case of good results, the test dust cannot be completely removed in a subsequent dust collector.

[0029] In this case, a certain degree of random sampling is performed, and it is checked whether, for example, prefabricated parts contaminated by such substances exist within a certain range of plastic prefabricated parts.

[0030] In another method, test dust is injected into each container so that only the contaminated containers are discharged under inspection control, thereby, particularly preferably, the powdery material can be adequately removed in a subsequent dust removal step.

[0031] Therefore, in this method, all plastic prefabricated parts or containers are inspected and subsequently cleaned.

[0032] The present invention also relates to an apparatus for inspecting containers, the apparatus having a conveying device for conveying containers along a predetermined conveying path, an insertion device for introducing powdered material into the containers, and an inspection device disposed downstream of the insertion device along the conveying path for inspecting containers containing powdered material.

[0033] Therefore, in terms of equipment, it is proposed that powdery substances, especially dust, be first introduced (e.g., blown into) into containers using an insertion device, and then these containers are inspected. Thus, in particular, the inspection device is used to inspect containers containing powdery substances, and especially to check whether certain surface areas have been impacted by the powdery substances, particularly the circumferential walls of the containers, in order to infer the presence of undesirable substances inside the containers.

[0034] In another preferred embodiment, the device has a manufacturing apparatus for manufacturing containers. Alternatively, a storage apparatus for storing containers can be provided.

[0035] In another preferred embodiment, the device has a discharge device arranged downstream of the inspection unit along the conveying path, the discharge device being adapted and intended for discharging containers from the container stream. All defective containers may be rejected, particularly in response to the results of the inspection unit. The discharge device can also discharge all containers containing powdery substances.

[0036] In another preferred embodiment, the insertion device has a nozzle for blowing in the powder. Particularly preferably, the insertion device has a reservoir in which the powdered material is disposed. Furthermore, the insertion device may have elements such as a sieve that allow the powdered material to enter the plastic container in fine granules.

[0037] In another preferred embodiment, the inspection device is an optical inspection device. The inspection device preferably inspects the container using either reflected light or transmitted light. Preferably, recording is performed both before and after injection (or normal insertion). Therefore, variations (in the appearance or result of the blown-in) are particularly effective for evaluation. Particularly preferably, the incident light inspection is color recording.

[0038] The inspection device preferably inspects the containers during container transport. The containers are preferably individualized. In this way, targeted discharge of specific containers is preferably possible.

[0039] Particularly preferably, the insertion device is a powder metering device. Preferably, such an insertion device, and especially a powder metering device, introduces powdered material into a gas mass stream, and particularly a (sterile) air mass stream.

[0040] Preferably, the insertion device or powder metering device is designed such that the introduction of powdered material can occur intermittently and / or within a predetermined time period. For example, powdered material can be added to the gas mass stream intermittently and / or at predetermined time periods. Additionally or otherwise, the gas mass stream can be operated intermittently and / or at predetermined time periods.

[0041] In this way, powdered materials can be introduced into individual plastic preforms.

[0042] Preferably, the gas used in the insertion device is selected from a group of gases including CO2, N2, air, sterile air, gaseous disinfectant, and mixtures thereof.

[0043] Alternatively, it is conceivable to mechanically drop the powder into (particularly suspended) the plastic preform in the first step, and to preferably create a distribution on the inner surface of the preform using small air pulses in the second step. An optical evaluation can be performed in an optional third step, followed, preferably, by rinsing with a gas or liquid cleaning step in an optional fourth step.

[0044] Preferably, the powdered substance and / or rinsing medium are compatible with the subsequent product to be filled. Compatibility is understood to mean that the powdered substance does not affect the intended characteristics of the product to be filled, such as its shelf life or its odor. Furthermore, the rinsing medium may also be a gaseous rinsing medium.

[0045] Further advantages and implementation schemes are shown in the accompanying drawings.

[0046] In the attached diagram:

[0047] Figure 1 A block diagram representation of the device according to the present invention is shown.

[0048] Figure 1 A block diagram of an apparatus 1 for inspecting a container 10 according to the present invention is shown. Here, reference numeral 22 indicates equipment for producing plastic preforms, such as an injection molding machine. The plastic preforms produced in this equipment can be conveyed to the insertion device 4 via a conveying device.

[0049] Alternatively, the plastic preform can also be stored in storage device 24 (such as a container) and also transferred from storage device to insertion device 4.

[0050] Reference numeral 2 schematically indicates a conveying device that transports plastic preforms from the insertion device of the inspection device to this location. Here, equipment 1 has multiple such conveying devices that transfer plastic preforms or conventional containers from one station to another.

[0051] Dust is introduced into a container within the insertion device. In this context, the insertion device may, for example, have a nozzle that blows a specific amount of powdery material into the container.

[0052] The container 10, filled with the powdered substance, is now conveyed from the insertion device to the inspection device. This allows for visual inspection of the container and determines whether the powdered substance has been deposited on the inner surface of the container.

[0053] Reference numeral 12 indicates a discharge device for removing certain containers from the product stream, as shown by arrow P1. All containers with introduced powdery material can be discharged. However, only those containers already identified as defective, such as those detected by inspection equipment as having powdery material deposits on their inner walls, can be rejected.

[0054] Reference numeral 14 indicates a cleaning device, such as a blower, that removes powdery material from a container. In this process, the powdery material can be blown out of the container, for example. It is also conceivable that the container be inverted and conveyed, for example, with the opening facing downwards, for this cleaning purpose.

[0055] In addition, cleaning can also be done with the help of liquids.

[0056] Reference numeral 16 indicates a heating device for heating a plastic preform, and reference numeral 18 indicates a molding device for molding the plastic preform into a plastic container.

[0057] Reference numeral 20 indicates a control device for controlling the entire system. This control device 20, for example, can control the discharge device to discharge certain containers 10 from the product stream.

[0058] and Figure 1 Alternatively, the insertion device can be arranged in a separate conveying branch, and all containers passing through the insertion device are subsequently discharged.

[0059] The applicant reserves the right to claim protection for all features essential to the invention disclosed in the application documents, provided that they are novel, individually or in combination, relative to the prior art. It should also be noted that features that may be advantageous in themselves are also depicted in the various figures. Those skilled in the art will readily recognize that specific features described in the figures can be advantageous even without employing additional features from those figures. Furthermore, those skilled in the art will recognize that advantages can also arise from combinations of several features shown in a single or different figures.

[0060] List of reference numerals

[0061] 1 Equipment

[0062] 2 Conveying device

[0063] 4. Insertion device

[0064] 6. Inspection device

[0065] 10 containers

[0066] 12 Discharge device

[0067] 14. Cleaning equipment and blowing equipment

[0068] 16 Heating device

[0069] 18 Forming device

Claims

1. A method for inspecting a container (10), the method comprising: - Provide an unfilled container (10); - Introduce the powdered substance into the interior of the container; - The container is optically inspected by means of an inspection device (6), wherein The inspection device (6) checks whether the powdery substance is adhered to the wall of the container (10). This serves as an indication of the presence of a material that is not visible in the container. The powdery substance adheres to the wall of the container, thereby allowing the inference from the presence of the powdery substance on the wall of the container that an unwanted substance is located in the container.

2. The method according to claim 1, Its features are, The volume of the substance introduced into the interior of the container (10) is less than 20% of the interior of the container (10).

3. The method according to any one of claims 1-2, Its features are, The conveying device (2) conveys the container to the insertion device (4), which introduces the powdered substance into the container, and / or the conveying device (2) conveys the container with the powdered substance to the inspection device (6).

4. The method according to claim 1, Its features are, The container (10) is a plastic container.

5. The method according to claim 1, Its features are, The powdered substance is introduced into the interior of the container (10).

6. The method according to claim 1, Its features are, The powdery substance is corundum or contains corundum.

7. The method according to claim 1, Its features are, The powdered material has a particle size of at least 10 µm, and / or the powdered material has a particle size of up to 400 µm.

8. The method according to claim 1, Its features are, The container (10) containing the powdered substance is separated and / or cleaned.

9. An apparatus for inspecting a container (10), the apparatus having a conveying device (2) for conveying the container (10) along a predetermined conveying path, an insertion device (4) for introducing a powdery substance into the container, and an inspection device (6) arranged downstream of the insertion device (4) along the conveying path for inspecting the container containing the powdery substance, the inspection device (6) inspecting whether the powdery substance is adhered to the wall of the container (10), which serves as an indication of the presence of a material invisible in the container, the powdery substance adhering to the wall of the container, thereby enabling the inference from the presence of the powdery substance on the wall of the container that an unwanted substance is located in the container.

10. The device according to claim 9, Its features are, The device has a discharge device (12) arranged along the conveying path after the inspection device (6), the discharge device being adapted to discharge the container from the container flow.

11. The device according to any one of claims 9 to 10, Its features are, The insertion device is a powder metering device.

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