JPS63304126A - Inspecting instrument for container - Google Patents

Abstract

PURPOSE:To exactly detect a defective without causing an erroneous detection due to a fluctuation of pressure in a branch supply path, by determining a threshold level for deciding non-defective or defective, based on each pressure detected value at the time when a normal container has been installed and detached to and from a compressed air supply means. CONSTITUTION:Compressed air generated by a compressor, etc., passes through a supply pipe 21, a pressure controller 22 and a pipe line 23 and led to an injection port 24. To the injection port 24, a pet bottle 25 being a container to be inspected is installed by a detaching/attaching device 26. In this state, pressure of air in the pet bottle 25 is detected by a semiconductor pressure sensor 27 connected through the pipe line 23. At the preparation stage of an inspection, pressure at the time when a normal bottle has been installed, and pressure in a state that no bottle is installed are measured, stores in memories 32, 33, and from the measured value, a threshold level is calculated and stored in a memory 34. By comparing the value of the memory 34 and pressure of the bottle to be inspected 25, a defective is decided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a container inspection device, and more particularly to a container inspection device that inspects the container by sending compressed air into the container.

[Conventional technology]

Container inspection devices are used to detect any abnormalities in manufactured containers. In order to detect pores, cracks, etc. in a container, a device is generally used that sends compressed air into the container and measures the air pressure at that time.

FIG. 4 shows a structural diagram of a bottle inspection device as an example of a conventional general container inspection device. Compressed air is supplied from a compressor or the like to the supply pipe 1 and given to the regulators 2 and 3. Air whose pressure is regulated by the regulator 2 is injected into the bed bottle 6 via the pipe line 4 and the inlet 5. Since the mouth of the bed bottle 6 is brought into close contact with the inlet 5 by the attachment/detachment device 7, the pressure set by the regulator 2 is applied inside the bed bottle 6. This compressed air is also transmitted to a differential pressure detector 9 via a pipe line 8. The differential pressure detector 9 is connected to two chambers 9 by an elastic membrane 10 made of natural rubber or synthetic rubber.
It is divided into chambers a and 9b, and the compressed air transmitted through the pipe line 8 is given to the first chamber 9a. On the other hand, air adjusted to a predetermined reference pressure by the regulator 3 is supplied to the second chamber 9b via the conduit 11.

In the end, the bed bottle pressure is applied to the first chamber 9a of the differential pressure detector 9, and the reference pressure is applied to the second part P9b.
The elastic membrane 10 moves according to the pressure difference between the two chambers.

A first contact 12 is provided in the first chamber 9a, and a second contact 13 is provided in the elastic membrane 10, forming a detection section 14 as shown by the broken line in the figure. If the bed bottle 6 is in a normal state without micropores or cracks, the bed bottle pressure and the reference pressure are approximately equal, so both contacts of the detection unit 14 are separated. However, if micropores or cracks are formed in the bed bottle 6, air escapes through the holes and a pressure loss occurs. Therefore, the bed bottle pressure decreases, the elastic membrane 10 moves toward the first chamber 9a as shown in FIG. 5, and both contacts of the detection section 14 come into contact. By electrically detecting contact between both contacts 12 and 13, it is possible to detect that the bottle 6 is defective.

[Problem that the invention seeks to solve]

However, the conventional container inspection apparatus described above has a problem in that it cannot accurately detect defects. That is, the pressure of the compressed air from the regulators 2 and 3 is a minute pressure of about 500 amAq, and this pressure is uneven. Therefore, if the air supply path is branched into two, separate pressure fluctuations will occur in each branch path, and this pressure fluctuation will prevent the differential pressure detector from operating properly, making it impossible to completely detect defective products. Situations may arise where this cannot be done.

Therefore, an object of the present invention is to provide a container inspection device that can accurately detect defects.

[Means for solving problems]

The present invention provides a container inspection device comprising: an air supply means for supplying compressed air through an injection port; an attachment/detachment means for attaching and removing a container from the injection port; and pressure of the air supplied by the air supply device. and the detection value P of the pressure sensor when the desorption device is detached from the container.
0, and the detection value P1 of the pressure sensor when a normal container is attached to the desorption device, and a coefficient α (0<α<1) determined by the operator's settings, p −p +α(P, - Po) T.

Determine the threshold value Pr expressed by the formula, compare the detection value P of the pressure sensor when the container to be inspected is attached to the desorption device with the threshold value PT, and determine that P8<P. A determination means for generating a defective detection signal when the determining means generates a defective detection signal; and a defective product rejection means for rejecting a container attached to the inlet as a defective product when the determining means generates a defective detection signal. .

[For production]

According to the container inspection device according to the present invention, only one compressed air supply path is required. The standard pressure when air is injected into a normal container from this one supply path is set in advance M1, and the pressure when air is injected into the container to be inspected from the same supply path is used as the standard. By comparing with the pressure, it is possible to judge whether the object to be inspected is good or bad.

Therefore, erroneous detection due to pressure fluctuations between two supply channels, which is the case with conventional devices, is eliminated, and defective products can be detected accurately.

〔Example〕

The present invention will be described below based on illustrated embodiments. FIG. 1 is a block diagram showing the configuration of a container inspection device according to an embodiment of the present invention. Compressed air generated by a device such as a compressor is supplied to the supply pipe 21, and the pressure of this compressed air is adjusted to about 500 auAq by a regulator 22, and is guided through a pipe line 23 to an inlet 24, and is then poured into a plastic bottle 25. is injected into. The mouth of the bed bottle 25 is tightly connected to the inlet 24 by an attachment/detachment device 26.

On the other hand, the pressure of the air inside the PET bottle 25 is detected by a semiconductor pressure chamber 27 connected via a conduit 23. This detected value is amplified by an amplifier 28, converted into digital data by an A/D converter 29, and provided to a determining means 30.

In this embodiment, the determining means 30 includes a CPU 31, memories 32 to 34, and a coefficient setter 35, and generates a defect detection signal when a defective product is detected. The defective product exclusion system 36 has the function of excluding the attached bottle as a defective product when a defect detection signal is input from the determining means 30.

FIG. 3 shows a specific example of the configuration of the transport and desorption system for the bed bottle 25. FIG. 3(a) is a top view of this system, and FIG. 2(b) is a side sectional view of this system taken along cutting line XX (both figures are on different scales for convenience of explanation). The bed bottles 25 are conveyed by the first conveyor 41 at regular intervals in the direction of the arrow in the figure. A turntable 43 is provided at the end of the first conveyor 41 and rotates in the direction of the arrow in the figure. This turntable 43 is provided with four support holes 44 and has a structure capable of supporting the bet bottle 25. The bed bottle 25 that has been conveyed on the first conveyor 41 is supported by the support hole 44 of the turntable 43 at stage a, and after moving to stage d via stages b and c, the bottle 25 is conveyed by the second conveyor 42. It is transported in the direction of the arrow.

The air pressure of the bed bottle 25 is measured at the stage b position. Stage b as shown in Figure 3(b)
At this time, the inlet 24 of the conduit 23 is brought into contact with the mouth of the bed bottle 25 by the attachment/detachment device 26 . Then, as described above, the air pressure inside the bottle is detected. If the defect detection signal is not output from the determination device 30,
This bottle passes through stages c and d and is transported by the second conveyor 42 as a good product. However, when a defect detection signal is output from the determination device 30, the bottle is removed at stage C by the defective product removal system 36, and the bottle is not transported by the second conveyor.

Next, the operation of this device will be explained. The operation of this device is divided into two stages: a preparation stage and an inspection stage. In the preparation stage, the detection value P1 of the pressure sensor 27 when a normal bottle is attached is measured. In this case, it is preferable to prepare a plurality of normal bottles and calculate the average. Also, the detection value P of the pressure sensor 27 when no bottle is attached at all. is also measured. In this case as well, it is preferable to calculate the average of multiple M1 constant results. As described above, this apparatus has a mechanism as shown in FIG. 3, and the bed bottle 25 is supplied to the position of the stage b for detecting pressure at predetermined time intervals (for example, 0.5 seconds). Therefore, if, for example, 10 normal bed bottles 25 (bottles previously determined to be non-defective by another method) are flowed onto the first conveyor 41, the pressure sensor 25
7, the measurement results shown in FIG. 2 are obtained. This graph has 10 peaks, and each of these peaks has 1
Corresponds to the pressure when air is injected into 0 bottles.

The valley formed between the peaks corresponds to the pressure when the bottle is in the detached state, that is, when the bottle is not attached to the inlet 24. Here, if the average value of the peaks is Pl and the average value of the valleys is P, then Pl and Po represent the average pressure values when the bottle is in the apparatus and when it is removed from the apparatus, respectively.

In reality, the measured value converted into digital data by the A/D converter 29 is given to the CPU 31, and the
Po and Pl are calculated by the PU 31 and stored in the memories 32 and 33, respectively.

Subsequently, the operator inputs the coefficient α from the coefficient setter 35. This coefficient α is a number having a value of 0<α<1, and is a coefficient for determining the threshold value PT. That is, C
The PU 31 calculates the threshold value PT by calculating P −P +α(P, −Po) O based on the values Po, Pl and coefficient α in the memory 32.33, and stores this in the memory 34.
to be memorized. This threshold value PT is P as shown in FIG. -P, and is a value that serves as a criterion for determining defective products in the inspection stage that will be performed later.

After the above F17i step is completed, the actual inspection step can be performed. That is, the bottle bottles 25 to be inspected are passed onto the first conveyor 41''-, and are taken up one after another by the turntable 43, and the pressure inspection is performed at stage b. The CPU 31 compares the pressure Ps measured at stage b with a threshold value P stored in the memory 34, and generates a defect detection signal when Ps is less than P. A normal bottle should show a value close to Pl, so if the measured pressure P is smaller than the threshold PT, the bottle has micropores that cause air leaks.
If there are cracks, etc., it can be determined that the product is defective. As a result, a defect detection signal is generated from the determining means 30, and the bottle is rejected by the defective product elimination system 36 when it reaches stage C. In this way, among the bottles to be inspected, non-defective products are conveyed to the second conveyor 42, and defective products are discharged from the turntable 43.

Note that the value of the coefficient α is preferably close to 1 in order to improve detection accuracy and detect even the slightest air leak, but as shown in the graph in Figure 2, there may be some fluctuation in the detected value. Therefore, in order to avoid erroneous detection of good products as defective products, it is preferable to set the value to a value as low as possible from 1.

In this way, the coefficient α can be set to an optimal value depending on the balance between detection accuracy and false detection rate.

Also, during the inspection, the pressure P in the valley is always maintained. Pay attention to this pressure P. Threshold value P for the next container inspection depending on the fluctuation of
By resetting T, even more accurate inspection can be performed. That is, the value of the valley immediately after inspecting the n-th container to be inspected is P. (n), then (
Threshold value P T for n + 1)th container
(n + 1) may be set to a value determined by the following equation.

P (n + 1) −P o (n) + α (P■
+Po) The present invention has been described above based on an example using a bed bottle, but the present invention is not limited to a bed bottle, but can also be applied to plastic containers, carton containers, paper cups, paper cans, pillared cups, stand bags, bags, etc. It can be applied to inspection of any container. Also, the first
The configuration of the determination means 30 in the figure is shown as one example, and the present invention is not limited to only such a configuration.

〔Effect of the invention〕

As described above, according to the present invention, in a container inspection device, the pressure inside the container when a normal container is attached and the pressure inside the container when it is removed are detected in advance, and these values and the object to be inspected are detected in advance. It is possible to detect whether the product is good or defective by comparing the internal pressure of the container, and the detection level can be set by the coefficient α, so that it is possible to accurately detect defects.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a container inspection device according to an embodiment of the present invention, FIG. 2 is a graph for explaining the operation of the device shown in FIG. 1 in the preparation stage, and FIG. ) and (b) are a top view and a side sectional view, respectively, of the transport/detachment system of the device shown in FIG. 1, FIG. 4 is a block diagram showing the configuration of a conventional container inspection device, and FIG. FIG. 3 is a partial diagram for explaining the operation of the device shown in FIG. 1... Supply pipe, 2.3... Regulator, 4...
Conduit, 5... Inlet, 6... Bed bottle, 7...
・Detachment device, 8... Pipeline, 9... Differential pressure detector, 10
. . . Elastic membrane, 11 . . . Conduit, 12. 13 . . . Contact, 14 . ...Inlet, 25
...PET bottle, 26...Detachment device, 27...
semiconductor pressure sensor, 28... amplifier, 29... A/
D converter, 30...determination means, 31...CPU
, 32-34...memory, 35...coefficient setter, 3
6... Defective product exclusion system, 41... First conveyor, 4
2... second conveyor, 43... turntable,
44...Support hole. Applicant's agent Yusuke Sato 1 Figure Time Quantitative Life Figure 2 ``8 (b) Figure 63 Figure 5 Procedural Amendment Letter July 78, 1986

Claims (1)

[Scope of Claims] 1. Air supply means for supplying compressed air through an injection port; Attachment/detachment means for attaching and detaching a container to and from the injection port; a pressure sensor that detects pressure; a detection value P_0 of the pressure sensor when the detachment device is detached from the container; a detection value P_1 of the pressure sensor when the detachment device is attached with a normal container; Coefficient α (0<α<
Based on 1), a threshold value P_T expressed by the formula P_T=P_0+α(P_1-P_0) is determined, and the detection of the pressure sensor when the container to be inspected is attached to the detachment device is determined. determining means for comparing a value P_S with the threshold P_T and generating a defective detection signal when P_S<P_T; and a determining means attached to the inlet when the determining means generates a defective detection signal. A container inspection device comprising: a defective product exclusion means for rejecting a container as a defective product. 2. The container inspection device according to claim 1, wherein the pressure sensor is a semiconductor pressure sensor provided in the middle of a compressed air transmission pipe. 3. The container inspection device according to claim 1 or 2, wherein the determination means uses an average of detection values for a plurality of normal containers as the detection value P_1.