JP7623934B2 - Resin bottle inspection device and inspection method - Google Patents

Description

The present invention relates to an apparatus and method for inspecting for defects such as pinholes during the manufacturing process of plastic bottled beverages.

Currently, PET bottle beverages are subject to the risk of defects such as leakage caused by pinholes due to poor molding of the bottle, so pinholes are detected during inspection at the time of production.

A known example of a conventional inspection device is a PET bottle leak inspection device 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 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 from a compressed air source into the PET bottle through the head in this state. After a predetermined amount of compressed air is supplied into the PET bottle, the inside of the PET bottle is sealed, and while the main rotor transports the PET bottle along a circular orbit, the pressure inside the PET bottle is measured after a predetermined time has passed using a pressure sensor connected to the head, and a leak from the PET bottle is detected.

JP 2012-103020 A

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.

In addition, if a resin bottle has a hole in the body, after it has been filled with a beverage or the like, defects in the resin bottle can be detected by using an existing bottle inspection device to detect a decrease in the amount of liquid due to leakage from the hole.

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

The object of the present invention is to provide a resin bottle inspection device and inspection method that can detect the presence or absence of defects in resin bottles with high accuracy while having a simple configuration.

The inspection device according to the present invention is characterized in that it is equipped with a conveying means for conveying the resin bottle in an upright state after 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.

According to this configuration, by compressing the resin bottle in the vertical direction, the change in the liquid level inside the bottle can be detected, making it possible to more accurately detect the presence or absence of defects in the resin bottle.

For example, if a hole exists in the headspace of a plastic bottle, defects in the plastic bottle can be detected by detecting the rise in liquid level caused by air escaping during compression. Also, if a hole exists in a body part of the plastic bottle other than the headspace, the plastic bottle can be compressed to encourage the beverage to leak from the hole, making it easier to detect a decrease in liquid volume due to liquid leakage, and as a result, the accuracy of detecting defects in plastic bottles is improved.

Furthermore, since it is only necessary to provide a compression means and a detection means, the device configuration is not complicated, it is easy to incorporate into existing manufacturing lines, and equipment costs can be kept low.

The inspection device according to the present invention is preferably provided with a determination means for determining whether or not there is a hole in the resin bottle based on the position of the liquid level.

With this configuration, by providing a separate determination means, it becomes possible to more accurately and quickly determine whether or not there is a hole.

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

According to this configuration, the presence or absence of a hole in the head space portion 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 portion other than the head space portion 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 where they are in the resin bottle.

In the inspection device according to the present invention, 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 decreases toward the downstream side in the conveying direction of the resin bottle, and the resin bottle is compressed by the compression means pressing more strongly against the upper surface of the cap of the resin bottle as the resin bottle moves.

The compression means of this configuration can reliably compress the resin bottle while transporting it without impeding its movement, making it possible to detect defects more efficiently. In addition, since the compression means is located above the transport means, there is no need to provide a dedicated installation space.

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

This configuration allows the resin bottle to be compressed more reliably while being transported more smoothly.

The inspection device according to the present invention is preferably provided with a preliminary detection means for detecting the position of the liquid level in the resin bottle before compression by the compression means.

With 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, further improving the accuracy of defect detection.

The inspection method according to the present invention is characterized in that it includes a transport step in which the resin bottle is transported in an upright position after the liquid filling step and the capping step, a compression step in which the resin bottle is compressed in the vertical direction, and a detection step in which the position of the liquid level in the resin bottle after the compression start point is detected.

According to this method, by compressing the resin bottle in the vertical direction, the change in the liquid level inside the bottle can be detected, making it possible to more accurately detect the presence or absence of defects in the resin bottle.

FIG. 2 is a schematic side view of the inspection device. 1A and 1B are diagrams for explaining the position of the liquid level when there is a hole in the head space of a plastic bottle 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. 1A and 1B are diagrams illustrating the position of the liquid level when a resin bottle beverage has a hole in the body part other than the head space part, 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.

[Embodiment]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 conveying direction of the resin bottles P.

(Resin bottle beverage production line)
The plastic bottle beverage production line in this embodiment includes a blow molding machine, a plastic bottle transport means, cleaning equipment, beverage filling equipment, a capping device, an inspection device, a labeller device, a filled bottle inspection device, and the like.

The resin bottles molded by the blow molding machine are transported to a cleaning facility by a transport means such as a belt conveyor, where the cleaning process is carried out. The washed resin bottles are then transported to a beverage filling facility where the filling process is carried out, after which a capping device carries out a capping process in which the bottle caps are attached.

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

(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 a hole H is present in the resin bottle P.

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 the 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.

The conveying means 2 can be a known belt conveyor that supports the bottom surface of the resin bottle P while conveying it.

The preliminary detection means D3 includes a third imaging device 6 and an image processing device such as a computer (not shown). The third imaging device 6 includes a lighting device 6a and a camera 6b, and is positioned upstream of the compression means 3 described below. 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 transmitted light from the resin bottle P. Then, as shown in FIG. 2(a) or FIG. 3(a), the image obtained 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.

The compression means 3 is provided above the conveying means 2 along the extension direction of the conveying means 2, and is inclined so that the distance from the conveying means 2 decreases toward the downstream side of the conveying direction of the resin bottle P. In other words, the compression means 3 functions as a pressing means that gradually presses down the resin bottle P from above during conveyance, and as the resin bottle P is conveyed, the compression means 3 presses down more firmly against the top surface of the cap of the resin bottle P, thereby compressing the resin bottle P.

The compression means 3 can be constructed 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.

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 to an extent that no deformation due to compression remains in the resin bottle P that has passed through the compression means 3.

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 disposed at the end portion of the compression means 3. The end portion of the compression means 3 refers to the most downstream portion of both ends 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 the transmitted light from the resin bottle P. Then, as shown in FIG. 2(b) or FIG. 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.

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 the transmitted light from the resin bottle P. Then, as shown in FIG. 2(c) or FIG. 3(c), the image obtained is processed by an image processing device to detect the position of the liquid level S in the resin bottle P after the compression by the compression means 3 is released. Note that an existing filled bottle inspection device may be used for the first detection means D1.

The determination means first measures the distance T between the liquid level S detected by the backup detection means D3 and the bottom end 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 that is a distance T from the bottom end 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 that is a distance T minus the amount of compression C from the bottom end of the bottle cap BC is set as a second reference line S2 (see FIG. 2(b) or FIG. 3(b)).

Then, if the liquid level S detected by each of the first detection means D1 and the second detection means D2 does not change the distance T between the liquid level S detected by the backup detection means D3 and the bottom end of the bottle cap BC, the determination means determines that there is no hole H (defect) in the resin bottle P.

On the other hand, the determination means determines that the resin bottle P has a hole H (defect) 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.

When a hole H exists in the head space portion HS of the resin bottle P, as shown in FIG. 2(b), when the resin bottle P is compressed, air escapes from the hole H, causing the liquid level S to rise above the second reference line S2. Then, as shown in FIG. 2(C), when the compression by the compression means 3 is no longer performed, 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 backup detection means D3 (see FIG. 2(a)), i.e., the position of the first reference line S1. Therefore, when 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 head space portion HS of the resin bottle P.

In addition, if a hole H exists in the body part of the resin bottle P other than the head space 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 beverage L in the resin bottle P is likely to leak from the hole H due to compression. Therefore, as shown in FIG. 3(C), when compression by the compression means 3 is eliminated, an amount of air equivalent to the leaked beverage L enters through the hole H, and as a result, the liquid level S falls 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 the body part of the resin bottle P other than the head space portion HS.

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

(Testing Method)
The method for inspecting the resin bottle P in this embodiment includes the following steps:
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 judging the presence or absence of a hole H in the resin bottle P. 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.

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 that is a distance T minus the amount of compression C from the bottom end of the bottle cap BC when the resin bottle P is compressed is set as the second reference line S2 (see FIG. 2(b) or FIG. 3(b)). In addition, a line that is a distance T from the bottom end of the bottle cap BC of the resin bottle P after the compression is released is set as the first reference line S1 (see FIG. 2(c) or FIG. 3(c)).

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.

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 compression in the second detection process is above the second reference surface S2, it is determined that the resin bottle P has a hole H (defect).

Other embodiments
1. In the above-described embodiment, the preliminary detection means D3 or the preliminary detection process may not necessarily be provided when the first reference line S1 and the second reference line S2 are determined in advance, for example, when the position of the liquid level S after the filling process is already known from a past filling result.

2. The first detection means D1 or the first detection process in the above-described embodiment does not necessarily have to be provided, and the configuration may include only the second detection means D2 or the second detection process.

3. Since the proportion of the headspace portion HS in the entire resin bottle P is significantly smaller than the portion other than the headspace, the possibility of a hole occurring is significantly low or is considered to be almost nonexistent. In such a case, the second detection means D2 or the second detection process in the above-mentioned embodiment does not necessarily have to be provided, and a configuration including only the first detection means D1 or the first detection process may be used.

4. The judgment means or judgment process in the above-mentioned embodiment may not necessarily be provided, for example, in cases where an inspector makes the judgment directly.

The embodiments disclosed in this specification are merely examples, and the present invention is not limited to these embodiments. They may be modified as appropriate without departing from the scope of the present invention.

The present invention can be suitably used in the field of technology related to the production of plastic bottled beverages.

1 Inspection device 2 Conveying means 3 Compression means 4 First imaging device 5 Second imaging device 5a Lighting device 5b Camera 6 Third imaging device 6a Lighting device 6b Camera D1 First detection means (detection means)
D2 Second detection means (detection means)
D3 Auxiliary detection means T Distance C Compression amount S Liquid level S1 First reference line S2 Second reference line P Resin bottle BC Bottle cap HS Head space portion H Hole L Beverage

Claims (6)

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. The inspection device according to claim 1, further comprising a determination means for determining whether or not a hole exists in the resin bottle based on the position of the liquid surface. The inspection device according to claim 1 or 2, wherein the detection means detects the position of the liquid level in the resin bottle when compression by the compression means is completed and after compression is released. The inspection device according to any one of claims 1 to 3, further comprising a preliminary detection means for detecting the position of the liquid surface in the resin bottle before compression by the compression means. 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. 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.

Images