JP3044473U - Seal inspection device for hermetically sealed products - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To detect and inspect defects such as defective seals that occur after filling the contents of hermetically sealed products. SOLUTION: An object 20 which is being transported in water is compressed at a same speed as a transporting machine by a squeezing mechanism, whereby bubbles leaking from a defective portion are collected by a bubble collecting cover 12 and ultrasonic bubble detection is performed. Provided is an inexpensive and highly reliable inspection device which is introduced into the sensor 11 and detects and inspects the presence or absence of bubbles here.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a device for inspecting a seal defect such as a pin hole of a packaging container that is hermetically filled with contents such as foods, cosmetics or medicines.

[0002]

[Prior art]

 As a conventional inspection device for sealing defects such as pinholes in hermetically sealed packaging containers, a voltage is applied to the test object by a positive electrode placed in the system while the test object is being transported by a carrier machine, 2. Description of the Related Art A so-called voltage application type pinhole inspection device, which is a principle that captures electrical changes between arranged negative electrodes, is well known.

[0003] Furthermore, a test object is housed in a pressure-tight sealed inspection container, and a positive pressure or a negative pressure is applied to the inspection container. There is a pressure type pinhole inspection device that detects and inspects.

[0004]

[Problems to be solved by the device]

 The voltage application type pinhole inspection device is based on the detection principle that the packaging material is a non-conductive material such as resin and the content is a conductive substance. In the case of aluminum vapor-deposited products or metal-based packaging materials whose surface is covered with aluminum foil, which is often used for packaging products, there is a drawback in that it cannot withstand use because the skin is conductive. Furthermore, the contents were dry substances, non-conductive materials, etc. were also undetectable.

Further, the pressurization type pinhole inspection device is characterized as a versatile device in which there are no restrictions on the material to be inspected, but it requires a precision-machined pressure-resistant container, etc. In particular, this system for the purpose of continuous automatic inspection processing of this method requires batch processing of pressure changes in each pressure vessel with a continuous mechanism, which results in high cost. I had an unavoidable fate.

[0006]

[Means for Solving the Problems]

 The present invention conveys a subject being transported in water while pressurizing it with a pressure within a safe range so as not to rupture, collects bubbles rising from a defective subject with a bubble collection cover, and introduces them into the sensor conduit. The presence of bubbles is detected by comparing the ultrasonic signal change in the conduit with that of uniform water.

Regarding the technique of detecting the bubbles contained in the liquid by ultrasonic waves, there have been many known methods from JP-B-33-6903 to JP-B-58-2620, but the latter is particularly preferable. Disturbance noise is eliminated by the double-check technique by detecting multiple units of transmission and reception. Based on this technique, the present invention applies it as a seal inspection device for hermetically sealed packages as a system, which collects bubbles rising in a water tank with a bubble collection cover and applies them to a bubble detection sensor. It provides the applicable equipment.

[0008]

[Embodiment of the invention]

 The present invention is an umbrella-like foam-collecting cover for air bubbles generated from a defective portion of a defective specimen when passing through a transport device arranged underwater in a water tank and a squeezing mechanism that freely compresses the specimen in parallel. Introduce it into the conduit of the bubble detection sensor, and provide a means to detect the presence of bubbles by detecting and comparing the signal change with homogeneous water while transmitting and receiving ultrasonic signals in the water in the conduit. In addition, a means for discharging the detected defective object to the outside of the system in the middle of the subsequent carrier by a signal based on the specific time difference calculated from the detection position and the carrier speed is provided. (Corresponding to claim 1)

It is well known from the experience of the inventor that the rising bubbles adhere to the inner surface of the foam collecting cover and stay there, and when the long-time use causes the generation of scale, the adhered bubbles are irregularly separated and the bubble sensor is removed. May mischief to prevent normal detection of. To avoid this, the foam collection cover and the bubble sensor are connected by an electric pump so that water is forcibly absorbed regardless of the presence or absence of rising bubbles from the foam collection cover, and the treated water discharged from the pump discharge pipe is returned to the water in the water tank. Means for forming a water circulation system and preventing adherence and retention of bubbles will be provided. (Claim 2)

As a control method for discriminating and confirming whether a bubble to be inspected or a disturbance bubble, it is controlled whether the bubble passing through the conduit of the bubble detection sensor is a single bubble or a continuous bubble group. Another method is to identify and confirm by detecting the detection frequency or detection time width of bubbles detected within a specified time by a timer in the circuit. (Corresponding to claim 3)

[0011]

【Example】

 Embodiments will be described with reference to the drawings. FIG. 1 shows the relative relationship between a main body 10 and a subject 20 of a seal inspection device for hermetically sealed packages according to the first, second and third embodiments of the present invention. The sensor body 10 includes a circulating water system such as an electric pump 21 and a discharge pipe 23, which are directly connected to a foam collection cover 12 and a bubble sensor 11 by a suction pipe 22, and an underwater carrier 31 and a subject squeezing mechanism including a free roller provided in parallel. It consists of 33, 34 and 35.

The subject squeezing mechanism is for transporting the subject 20 while compressing the subject 20 from the initial thickness h to the inspection thickness δ, and adjusts the gap δ formed with the upper surface of the carrier 31. A plurality of adjustment handles 35 and support rods 37 suspend and fix the clearance above the frame on the water surface so that the clearance can be adjusted.

FIG. 2 shows the relationship between the sensor main body 10 arranged in the water tank 32 and the underwater carrier 31, and the behavior of the subject 20 according to claims 1, 2 and 3 of the present invention. It is a clear view. FIG. 3 is a block diagram for explaining the control circuit of the bubble sensor.

The subject 20 is carried by an underwater carrier 31 arranged in a water tank 32, and is transported from the first stage free roller 33 of the subject squeezing mechanism provided next to the flat part at the bottom to the roller 33 ′ of the next stage and thereafter. After that, because of the gap formed on the upper surface of the conveyor 31 supported by these roller groups and the conveyor band supporting plate 37, the initial thickness h is the inspection gap δ adjusted to the safety side so that the subject does not burst. It enters in the direction A while being compressed.

When a defective object having a defect such as a defective seal passes directly under the bubble sensor 11 among the objects 20 continuously conveyed by the conveyor 31, the object 20 is lightly compressed by a free roller. Therefore, the air or gas inside leaks out from the defect and becomes upward rising bubbles. The bubbles are collected by the umbrella-shaped foam collecting cover 12 that has been awaited, and ascend and pass through the conduit 18 of the bubble sensor 11. In this case, the rising bubbles are forcibly absorbed by the electric pump 21, so that the bubbles do not adhere and stay in the system.

During the operation, the inside of the conduit 18 is always set to two sets which are integrally shaped with the outer peripheral portion of the conduit 18 and are spaced apart from each other based on the ultrasonic output transmitted from the ultrasonic oscillator 1 in the control circuit 30. The transmitting oscillators 2a and 2b are excited to emit a certain amount of ultrasonic energy into the water in the conduit to form an ultrasonic sound field.

When no bubbles are present in the water, the energy transmitted from the transmission oscillators 2a and 2b to the reception oscillators 3a and 3b arranged at opposite positions is always constant. Therefore, a corresponding voltage is induced in the receiving oscillators 3a and 3b.

On the other hand, when even one bubble exists in the water, the ultrasonic energy emitted from the oscillators 2a and 2b is scattered and absorbed by the bubble, so that the reception energy is attenuated accordingly. However, the output voltage is also lower than when there is no bubble. Thus, if a bubble enters the conduit 18, the presence of the bubble is detected by the difference between the voltage at which the attenuation decreases and the voltage when no bubble is present.

These difference signals are subjected to amplification processing in the high frequency amplification sections 4a and 4b in the control circuit 30 and shaping of signals in the signal shaping sections 5a and 5b, and then to the two sets of transmitting and receiving oscillators. The double check function eliminates external noise and detects the presence / absence of air bubbles in the comparator section 6 at the same time, and after low-frequency amplification, the output section 7 sends it as a signal to complete the function. Since the function of the control circuit during this period is a known technique, detailed description of the configuration and function of each unit will be omitted.

When the subject 20 enters the water in the water tank 32, bubbles may be attached to the outer periphery of the subject 20, and the bubbles may be irregularly peeled during transportation and enter the bubble sensor 11. Similarly, it may cause misidentification and malfunction.

A timer in the control circuit discriminates between the noise bubble of the single bubble and the bubble to be continuously generated for detection by detecting the detection frequency or the detection time width of the bubble detected within a certain specified time. It has a built-in control circuit to check and is equipped with a means to be guarded against misidentification due to noise bubbles.

As for the control circuit, there are a control circuit for automatic operation, which is the basis of the whole, and a control circuit for removing a defective object, which are within the scope of common sense. Therefore, detailed description is omitted.

[0023]

[Effect of the invention]

 The present invention is embodied in the form described above and has the following effects.

The conventional voltage application type pinhole inspection device has been put to practical use in a fairly wide range when the material of the object is a non-conductive material, but it is completely functional when the object is a conductive material because of its detection principle. There was a drawback not. The same was true when the contents were non-conductive substances.

On the other hand, the inspection device of the present invention has nothing to do with these attributes, and there is no problem in the seal inspection in the case of the aluminum vapor deposition film packaging material or the metal material which is often used in foods. It can be applied. Regarding the contents, the constraint condition is extremely small except for the condition of coexistence with gas and the fact that it is better to use a relatively soft substance.

Further, the crying point of the voltage application type pinhole inspection device is that in the case where the packaging material is a thin resin film, the inspection machine often makes a mischief of punching with its own applied voltage. . This is the fate of this method, and there was a limit to 100% improvement. On the other hand, in the inspection apparatus of the present invention, there is no concern about the packaging material thickness problem due to proper operation of the subject squeezing mechanism.

Further, the pressurization type pinhole inspection device is also not affected by the material of the packaging material in the same way, but this system is used for a device with a high degree of mechanical processing such as a group of many precision processed sealed inspection containers. Being structured, it requires a significant investment cost.

The inspection device of the present invention requires a corresponding manufacturing cost such as a bubble sensor unit and a control circuit. Judging from the experience of the inventor, the inspection device of the present invention is almost the same as that of the pressure type inspection device when compared by the same processing capacity. The cost will be reduced by an order of magnitude and the amount of investment will be in time, and the most important effect will be exhibited.

Since the inspection device of the present invention is mainly for in-water inspection in principle, the image of the device is a negative material because it is generally a wet type, but as a recent trend of food packaging products, sterilization is a major factor. There are many packs, and since the sterilization treatment is performed in hot water of the retort immediately after packaging, a cooling process is required continuously.If this cooling water tank and the inspection water tank of the present invention are combined, the cost can be increased at a low cost. Not limited to the food industry only.

Most of the above description assumes that the object product of the device of the present invention is a mixture of the content and air or gas even in a small amount, but in the case of food, there is no gas mixture. However, in the case of heat sterilization with hot water, in the case of liquid contents, the liquid content is gas-liquid separated due to heating close to boiling, and the packaged product becomes swollen and gas is present, so the inspection method using the squeezing mechanism is fully effective. I want to add what I can do.

Further, in the case of the voltage application method, if the amount of gas contained in the package is too much and the skin of the packaging material and the contents are severely separated, the detection effect may be significantly impaired in principle. Was in reality. On the other hand, in the device of the present invention, the amount of gas mixed in the package is not so much a problem, and conversely there is no problem in detecting a large amount of gas.

Further, as described above, the seal inspection method by the bubble detection of the present invention has the erasing means by double-checking the disturbance noise such as the impact applied to the sensor, and the object brought in by the subject. A single sensor with a control circuit that prevents disturbance can be used to reliably eliminate false positives due to bubbles that are not detected.

[Submission date] July 9, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

The subject squeezing mechanism is for transporting the subject 20 while compressing the subject 20 from the initial thickness h to the inspection thickness δ, and includes a plurality of gaps δ for adjusting the gap δ formed on the upper surface of the carrier. The adjustment handle 35 and the support rod 36 suspend and fix the gap from the frame on the water surface so that the clearance can be adjusted.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

[0017] Here, the energy when not exist air bubbles in the water to be transmitted transmitting transducer 2a, receiving transducer 3a which arranged in opposed position location from 2b, and 3b are always constant. Therefore receiving transducer 3a, the 3b, constant voltage corresponding thereto is induced.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

On the other hand, when there is even one bubble in the water, the ultrasonic energy emitted from the transducers 2a and 2b for transmission is scattered and absorbed by the bubble, so that the received energy is attenuated accordingly. , The output voltage is also lower than that without bubbles. Thus, when bubbles enter the conduit 18, the presence of bubbles is detected by the difference between the voltage of this attenuation decrease and the voltage when there is no bubble.

[Brief description of the drawings]

FIG. 1 is a side view showing a relationship between a sensor main body and a subject of a seal inspection device for hermetically sealed packages according to claims 1, 2, and 3 of the present invention.

FIG. 2 is a side view for explaining the entire seal inspection device for hermetically sealed products according to the first, second and third claims of the present invention.

FIG. 3 is a block diagram for explaining a control circuit of a bubble sensor of the present invention.

[Description of sign]

 1 Ultrasonic Oscillator 2 Transmitter Oscillator 3 Receiver Oscillator 4 High Frequency Amplifier 5 Signal Shaping 6 Comparison Part 7 Low Frequency Amplifier & Output 10 Sensor Body 11 Bubble Sensor 12 Bubble Cover 18 Conduit 20 Subject 21 Electric Pump 22 Suction pipe 23 Discharge pipe 30 Control circuit 31 Conveyor 32 Water tank 33 Free roller for squeezing 34 Compressing mechanism frame 35 Gap adjusting handle 36 Support rod 37 Conveyor band adjustment support plate

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 9, 1997

[Procedure amendment 4]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

[Fig. 2]

Claims (3)

[Utility model registration claims] 1. The presence of even a small amount of air bubbles in a liquid causes a change in the acoustic properties of the mixed liquid as compared with a homogeneous liquid without air bubbles. This property change is regarded as a change in ultrasonic signal in the liquid in the conduit. In a method for detecting bubbles in a captured liquid, a packaged product (20, hereinafter referred to as a test object) in which the contents being conveyed and moved by a conveyer (31) placed in water in a water tank are hermetically filled.
Both sides of the wide part of the product are transported while being compressed by a compressing mechanism (33, 34, 35 and 36) that can be moved together with a transporter while applying appropriate compression within a safe range that does not rupture. The rising bubbles generated by the leakage of air or gas from the section are captured by the foam collection cover (12) arranged above the transport surface of the submersible carrier (31), and introduced into the connecting conduit (18),
An air bubble sensor (11) for transmitting ultrasonic waves from one of the conduits, receiving the ultrasonic waves on the other side, amplifying and shaping the received signal, and detecting air bubbles leaking from the subject (20) by detection comparison with homogeneous water. ), And a discharge mechanism that discharges a defective sample detected as a result of air bubble detection to the outside of the system on the way of the subsequent transport machine based on a specific time difference by a signal. apparatus. 2. A foam collecting cover (12), a bubble sensor (11), and an upper portion of the conduit 18 of the bubble sensor and an electric pump (21) are integrally connected by a suction pipe (22). ) After forcibly sucking up the water on the lower surface and passing this water through the bubble sensor, the discharge pipe (23) of the electric pump
The seal inspection device for a hermetically sealed package according to claim 1, wherein a so-called water circulation system for returning the water from the container to the water in the water tank is configured. 3. The conduit (1) of the bubble detection sensor (11)
8) By a timer arranged in the control circuit for identifying whether a bubble passing through is a single bubble, a small bubble group close to this, or a large number of bubbles passing continuously, The hermetically sealed package seal inspection device according to claim 1, further comprising a control circuit for determining and specifying a limit bubble amount based on a detection frequency or a detection time width of bubbles passing within a set time.