Resin bottle inspection device and inspection method

Abstract

To provide an inspection device for a resin bottle that can precisely detect the existence of defects in the resin bottle, even by a simple structure.SOLUTION: An inspection device for a resin bottle comprises: conveyance means 2 which conveys a resin bottle P in an upright state after a liquid charging process and a cap mounting process; compression means 3 which compresses the resin bottle P vertically; and detection means D1, D2 which detect a position of a liquid level in the resin bottle P after the start point of compression by the compression means 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for inspecting for defects such as pinholes in a manufacturing process for resin bottled beverages. [Background technology]

[0002] Currently, PET bottled beverages carry the risk of defects such as leakage caused by pinholes due to poor bottle molding, so pinholes are detected during inspection at the time of manufacturing.

[0003] A known example of a conventional inspection device is a leak inspection device for PET bottles, as shown in Patent Document 1 below. In this inspection device, a PET bottle before being filled with a beverage or the like is placed on a container stand of a main rotor, the head of the device is lowered to abut against the mouth of the PET bottle, the mouth of the PET bottle is sealed with a gasket on the head, and compressed air is supplied into the PET bottle from a compressed air source through the head. A predetermined amount of compressed air is then supplied into the PET bottle, sealing the inside of the PET bottle. The PET bottle is then transported along a circular orbit by the main rotor, and after a predetermined time has passed, the pressure inside the PET bottle is measured using a pressure sensor connected to the head to detect leaks from the PET bottle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-103020 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional inspection devices require at least a compressed air supply means, a means for sealing the resin bottle after the compressed air has been introduced, and a pressure sensor for detecting pressure changes inside the resin bottle, making the device configuration complex and requiring dedicated installation space, making it difficult to incorporate into existing production lines.

[0006] Furthermore, if there is a hole in the body of a plastic bottle, after it has been filled with a beverage or the like, defects in the plastic bottle can be detected by using an existing bottle inspection device to detect a decrease in liquid volume due to leakage from the hole.

[0007] However, when detecting defects using a bottle inspection device, there is a problem in that if the hole is very small or if the hole is formed in the headspace area where no beverage is present, liquid leakage is unlikely to occur, making it difficult to detect defects, and a more accurate inspection method is required.

[0008] An object of the present invention is to provide a resin bottle inspection device and inspection method that are simple in configuration but are capable of detecting the presence or absence of defects in resin bottles with high accuracy. [Means for solving the problem]

[0009] The inspection device of the present invention is characterized in that it is equipped with a conveying means for conveying the resin bottle in an upright position after it has undergone the liquid filling process and the capping process, a compression means for compressing the resin bottle in the vertical direction, and a detection means for detecting the position of the liquid level in the resin bottle after the compression by the compression means starts.

[0010] According to this configuration, by compressing the resin bottle in the vertical direction, changes in the liquid level inside the bottle can be detected, making it possible to more accurately detect whether or not there is a defect in the resin bottle.

[0011] For example, if a hole exists in the headspace of a resin bottle, defects in the resin bottle can be detected by detecting the rise in the liquid level due to air escaping during compression. Also, if a hole exists in a body part of the resin bottle other than the headspace, compressing the resin bottle can encourage leakage of the beverage from the hole, making it easier to detect a decrease in liquid volume due to liquid leakage, resulting in improved accuracy in detecting defects in resin bottles.

[0012] Furthermore, since it is only necessary to provide a compression means and a detection means, the device configuration does not become complicated, it can be easily incorporated into existing manufacturing lines, and the equipment costs can be kept low.

[0013] The inspection device according to the present invention preferably includes a determination means for determining whether or not a hole exists in the resin bottle based on the position of the liquid surface.

[0014] According to this configuration, by providing a separate determining means, it becomes possible to more accurately and quickly determine whether or not there is a hole.

[0015] In the inspection device according to the present invention, it is preferable that the detection means detects the position of the liquid surface in the resin bottle when the compression by the compression means is completed and after the compression is released.

[0016] According to this configuration, the presence or absence of a hole in the headspace of the resin bottle can be detected by detecting the position of the liquid level at the end of compression, and the presence or absence of a hole in the body part other than the headspace can be detected by detecting the position of the liquid level in the resin bottle after compression is released. Therefore, holes can be reliably detected regardless of the part of the resin bottle where they are present.

[0017] In the inspection device of the present invention, the compression means is preferably provided above the conveying means along the extension direction of the conveying means, and is inclined so that the distance from the conveying means becomes smaller as it moves downstream in the conveying direction of the resin bottle, so that as the resin bottle moves, the compression means applies more pressure to the top surface of the resin bottle's cap, thereby compressing the resin bottle.

[0018] The compression means according to this configuration can reliably compress the resin bottles while transporting them without interfering with their movement, allowing for more efficient defect detection. Furthermore, since the compression means is located above the transport means, there is no need to provide a dedicated installation space.

[0019] In the inspection device according to the present invention, it is preferable that the compression means is a belt that moves in accordance with the conveying speed of the resin bottle.

[0020] According to this configuration, the resin bottle can be compressed reliably while being transported more smoothly.

[0021] The inspection device according to the present invention preferably includes a preliminary detection means for detecting the position of the liquid surface in the resin bottle before compression by the compression means.

[0022] According to this configuration, by detecting the position of the liquid level before compression, the reference liquid level position can be accurately determined for each resin bottle, thereby further improving the accuracy of defect detection.

[0023] The inspection method of the present invention is characterized in that it includes a transporting process in which a resin bottle is transported in an upright position after having undergone a liquid filling process and a capping process, a compression process in which the resin bottle is compressed in the vertical direction, and a detection process in which the position of the liquid level in the resin bottle after the compression start point is detected.

[0024] According to this method, by compressing the resin bottle in the vertical direction, changes in the liquid level inside the bottle can be detected, making it possible to more accurately detect whether or not there is a defect in the resin bottle. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 2 is a schematic side view of the inspection device. [Figure 2] This figure explains the position of the liquid level when there is a hole in the headspace of a plastic bottled beverage, where (a) shows the state before compression, (b) shows the state at the end of compression, and (c) shows the state after compression is released. [Figure 3] This figure explains the position of the liquid level when there is a hole in the body part of a plastic bottled beverage other than the headspace part. (a) shows the state before compression, (b) shows the state at the end of compression, and (c) shows the state after compression is released. DETAILED DESCRIPTION OF THE INVENTION

[0026] [Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In this specification, the terms "upstream" and "downstream" refer to the direction in which the resin bottles P are conveyed.

[0027] (Resin bottled beverage production line) The resin bottle beverage production line in this embodiment includes a blow molding machine, a resin bottle conveying means, cleaning equipment, beverage filling equipment, a capping device, an inspection device, a labeler device, a filled bottle inspection device, etc.

[0028] Resin bottles molded by a blow molding machine are transported to a washing facility by a transport means such as a belt conveyor, where they are washed. The washed resin bottles are then transported to a beverage filling facility where they are filled, and then a capping device is used to attach a bottle cap to the bottle.

[0029] After the filling process and capping process, the resin bottles are transported in an upright position by transport means 2 and inspected by an inspection device. Resin bottles P with detected defects are rejected, while those without defects are transported to a labeling device where a label is affixed. The resin bottles with labels affixed are checked for fill volume by a filling inspection device, and those that meet the standards are packaged and shipped.

[0030] (Inspection equipment) As shown in Figure 1, the inspection device 1 in this embodiment includes a conveying means 2 that conveys the resin bottle P in an upright position after the liquid filling process and the capping process, a compression means 3 that compresses the resin bottle P in the vertical direction, a detection means that detects the position of the liquid level S in the resin bottle P after the compression start point by the compression means 3, a preliminary detection means D3 that detects the position of the liquid level S in the resin bottle P before compression by the compression means 3, and a judgment means (not shown) that judges whether or not there is a hole H in the resin bottle P.

[0031] The detection means in this embodiment includes a first detection means D1 that detects the position of the liquid level S in the resin bottle P after compression by the compression means 3 is released, and a second detection means D2 that detects the position of the liquid level S in the resin bottle P when compression by the compression means 3 is completed.

[0032] As the conveying means 2, a known belt conveyor or the like that conveys the resin bottle P while supporting the bottom surface thereof can be used.

[0033] The preliminary detection means D3 includes a third imaging device 6 and an image processing device (not shown) such as a computer. The third imaging device 6 includes a lighting device 6a and a camera 6b, and is positioned upstream of the compression means 3, which will be described later. When the resin bottle P reaches the imaging position, the lighting device 6a illuminates the resin bottle P, and the camera 6b captures an image of the light transmitted through the resin bottle P. Then, as shown in FIG. 2(a) or 3(a), the obtained image is processed by an image processing device to detect the position of the liquid level S in the resin bottle P before compression by the compression means 3.

[0034] The compression means 3 is provided above the conveying means 2 in the extension direction of the conveying means 2, and is inclined so that the distance from the conveying means 2 decreases the further downstream in the conveying direction of the resin bottles P. In other words, the compression means 3 functions as a pressing means that gradually presses down on the resin bottles P from above as they are conveyed, and as the resin bottles P are conveyed, the compression means 3 applies more pressure to the top surfaces of the caps of the resin bottles P, thereby compressing the resin bottles P.

[0035] The compression means 3 can be configured using, for example, a known belt. When a belt is used as the compression means 3, it is desirable that the speed of the belt is linked to the conveying speed of the conveying means 2.

[0036] The longitudinal length of the compression means 3 is, for example, about 1.5 m, and the inclination angle is set so that the compression amount C of the resin bottle P is, for example, about 3 mm to 5 mm. It is desirable to set the compression amount C of the resin bottle P so that no deformation due to compression remains in the resin bottle P that has passed through the compression means 3.

[0037] The second detection means D2 includes a second imaging device 5 and an image processing device such as a computer (not shown). The second imaging device 5 includes a lighting device 5a and a camera 5b, and is located at the end portion of the compression means 3. The end portion of the compression means 3 refers to the most downstream of both end portions of the compression means 3, and the most upstream portion is referred to as the tip portion. When the resin bottle P reaches the imaging position, the lighting device illuminates the resin bottle P, and the camera captures an image of the transmitted light from the resin bottle P. Then, as shown in FIG. 2(b) or 3(b), the obtained image is processed by an image processing device to detect the position of the liquid level S in the resin bottle P at the end of compression by the compression means 3.

[0038] The first detection means D1 includes a first imaging device 4 and an image processing device such as a computer (not shown). The first imaging device 4 includes a lighting device and a camera (not shown), and is positioned downstream of the compression means 3. When the resin bottle P reaches the imaging position, the lighting device illuminates the resin bottle P, and the camera captures an image of the light transmitted through the resin bottle P. Then, as shown in FIG. 2(c) or 3(c), the obtained image is processed by an image processing device to detect the position of the liquid level S in the resin bottle P after compression by the compression means 3 is released. Note that an existing filled bottle inspection device may be used as the first detection means D1.

[0039] The determination means first measures the distance T between the liquid level S detected by the auxiliary detection means D3 and the bottom edge of the bottle cap BC (see FIG. 2(a) or FIG. 3(a)). Then, in the image obtained by the first imaging device 4 of the first detection means D1, a line located at the distance T from the bottom edge of the bottle cap BC is set as a first reference line S1 (see FIG. 2(c) or FIG. 3(c)). Furthermore, in the image obtained by the second imaging device 5 of the second detection means D2, a line located at a distance T minus the amount of compression C from the bottom edge of the bottle cap BC is set as a second reference line S2 (see FIG. 2(b) or FIG. 3(b)).

[0040] Next, if the liquid level S detected by each of the first detection means D1 and the second detection means D2 does not change in the distance T between the liquid level S detected by the auxiliary detection means D3 and the lower end of the bottle cap BC, the judgment means judges that there is no hole H (defect) in the resin bottle P.

[0041] On the other hand, the judgment means judges that there is a hole H (defect) in the resin bottle P when the liquid level S detected by the first detection means D1 is below the first reference line S1 and / or when the liquid level S detected by the second detection means D2 is above the second reference line S2.

[0042] If a hole H exists in the headspace portion HS of the resin bottle P, as shown in Figure 2(b), when the resin bottle P is compressed, air escapes through the hole H, causing the liquid level S to rise above the second reference line S2. Then, as shown in Figure 2(C), when compression by the compression means 3 ceases, air equivalent to the amount of air that escaped enters through the hole H, causing the liquid level S to return to the same position as the liquid level S detected by the preliminary detection means D3 (see Figure 2(a)), i.e., the position of the first reference line S1. Therefore, if the liquid level S detected by the second detection means D2 is above the second reference line S2, it is determined that a hole H exists in the headspace portion HS of the resin bottle P.

[0043] Furthermore, if a hole H exists in a body portion of the resin bottle P other than the headspace portion HS, as shown in FIG. 3(b), when the resin bottle P is compressed, the liquid level S is at the same position as the second reference line S2, but the compression makes it easier for the beverage L inside the resin bottle P to leak through the hole H. Therefore, as shown in FIG. 3(C), when compression by the compression means 3 is released, an amount of air equivalent to the leaked beverage L enters through the hole H, causing the liquid level S to drop below the first reference line S1. Therefore, if the liquid level S detected by the first detection means D1 is below the first reference line S1, it is determined that a hole H exists in a body portion of the resin bottle P other than the headspace portion HS.

[0044] Furthermore, if there is no hole H in the resin bottle P, neither air nor beverage L will leak out when the resin bottle P is compressed, so the liquid level S will be at the same position as both the first reference line S1 and the second reference line S2.

[0045] (Testing method) The method for inspecting a resin bottle P in this embodiment includes: The process includes a transport step of transporting the resin bottle P in an upright position after the liquid filling step and the capping step, a preliminary detection step of detecting the position of the liquid level S in the resin bottle P before compression, a compression step of compressing the resin bottle P in the vertical direction, a detection step of detecting the position of the liquid level S in the resin bottle P after the compression start point, and a determination step of determining whether or not a hole H exists in the resin bottle P. Note that the detection step in this embodiment includes a first detection step of detecting the position of the liquid level S in the resin bottle P after compression is released, and a second detection step of detecting the position of the liquid level S in the resin bottle P at the end of compression.

[0046] In the determination process, first, the distance T between the liquid level S detected in the preliminary detection process and the bottom end of the bottle cap BC is set (see FIG. 2(a) or FIG. 3(a)). Then, in the second detection process, a line located a distance (distance T - compression amount C) from the bottom end of the bottle cap BC when the resin bottle P is compressed is set as a second reference line S2 (see FIG. 2(b) or FIG. 3(b)). Furthermore, a line located a distance T from the bottom end of the bottle cap BC of the resin bottle P after compression is released is set as a first reference line S1 (see FIG. 2(c) or FIG. 3(c)).

[0047] Next, if the liquid level S detected in each of the first and second detection processes is at the same position as both the first reference line S1 and the second reference line S2, it is determined that there is no hole H (defect) in the resin bottle P.

[0048] On the other hand, if the liquid level S detected after the compression is released in the first detection process is below the first reference surface S1, and / or if the liquid level S detected at the end of the compression in the second detection process is above the second reference surface S2, it is determined that there is a hole H (defect) in the resin bottle P.

[0049] Other Embodiments 1. In the above-described embodiment, the preliminary detection means D3 or the preliminary detection process does not necessarily have to be provided if the first reference line S1 and the second reference line S2 are predetermined, for example, if the position of the liquid level S after the filling process is already known from past filling results.

[0050] 2. The first detection means D1 or the first detection step in the above embodiment does not necessarily have to be provided, and a configuration may be adopted in which only the second detection means D2 or the second detection step is included.

[0051] 3. Since the proportion of the headspace portion HS in the entire resin bottle P is significantly smaller than the portions other than the headspace, the possibility of holes occurring is significantly low or is considered to be almost non-existent. In such cases, the second detection means D2 or the second detection process in the above-described embodiment does not necessarily have to be provided, and the configuration may include only the first detection means D1 or the first detection process.

[0052] 4. The determination means or determination step in the above-described embodiment may not necessarily be provided in cases where, for example, an inspector directly makes the determination.

[0053] It should be noted that the embodiments disclosed in this specification are merely examples, and the present invention is not limited to these embodiments, and can be modified as appropriate within the scope of the purpose of the present invention. [Industrial Applicability]

[0054] The present invention can be suitably used in the field of technology related to the production of plastic bottled beverages. [Explanation of symbols]

[0055] 1. Inspection equipment 2. Means of transportation 3 Compression methods 4. First imaging device 5 Second imaging device 5a lighting equipment 5b Camera 6. Third imaging device 6a Lighting equipment 6b Camera D1 First detection means (detection means) D2 Second detection means (detection means) D3 Preliminary detection means T distance C Compression amount S liquid level S1 1st reference line S2 2nd reference line P Resin Bottle BC Bottle Cap HS headspace part H hole L Beverage

Claims

1. a conveying means for conveying the resin bottle in an upright state after the liquid filling step and the capping step; A compression means for compressing the resin bottle in the vertical direction; a detection means for detecting a liquid level in the resin bottle after a compression start point by the compression means, The compression means is provided above the conveying means along the extension direction of the conveying means, and is inclined so that the distance from the conveying means becomes smaller as it moves downstream in the conveying direction of the resin bottle, so that as the resin bottle moves, the compression means applies greater pressure against the top surface of the resin bottle's cap, compressing the resin bottle.This is a resin bottle inspection device.

2. 2. The inspection device according to claim 1, further comprising a determination unit that determines whether or not there is a hole in the resin bottle based on the position of the liquid level.

3. 3. The inspection device according to claim 1, wherein the detection means detects the position of the liquid surface in the resin bottle when the compression by the compression means is completed and after the compression is released.

4. The inspection device according to any one of claims 1 to 3, further comprising a preliminary detection means for detecting a position of a liquid surface in the resin bottle before compression by the compression means.

5. 2. The inspection device according to claim 1, wherein the compression means is a belt that moves in accordance with the conveying speed of the resin bottle.

6. A method for inspecting a resin bottle using the inspection device according to any one of claims 1 to 5, comprising: a conveying step of conveying the resin bottle in an upright state after the liquid filling step and the capping step; a compressing step of compressing the resin bottle in an up-down direction; and a detection step of detecting the position of the liquid level in the resin bottle after the compression start point.

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