JPH11183303A - Container leak detection method and leak detection device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] When a container is filled with pressurized gas and gas leakage is detected using a sound wave sensor to detect leakage of the container, noise other than gas leakage is accurately cut. SOLUTION: When detecting leakage of a container by detecting gas leakage from a container filled with a pressurized gas accommodated in a sound insulation space by a sound wave sensor, the leak detection device detects an output level of the sound wave sensor. Determining means, timing means, and determining means for determining that there is a leak in the container when the output of the sound wave sensor continues at a predetermined level for a predetermined time or more,
Instantaneous sounds such as drops of water drops are accurately cut as noise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting leaks of containers, and more particularly to a method and apparatus for detecting leaks of containers automatically and continuously on-line.

[0002]

2. Description of the Related Art In a container for filling a fluid, a container in which a pressurized gas is enclosed is required to ensure the airtightness of the container. As such a container, for example, there is a stainless steel barrel container filled with beer. FIG. 6 shows the appearance of a keg container for filling beer, and FIG. 7 shows the internal structure near the keg opening.

[0003] The barrel 100 is provided with a base 102 at an upper portion of a container body 101 and a cylindrical portion 103 extending from the container body 101 at a lower portion. The base 102 includes a valve for introducing and discharging beer, and a valve mechanism for sealing a pressurized gas inside. FIG. 7 shows these valve mechanisms. A fitting 103 is fixed to the base 102 by screwing, and a joint between the base 102 and the fitting 103 is a seal ring 104.
Sealed by The fitting 103 has a bush 105 screwed into the base 102 and a down tube 106 whose tip extends to near the bottom of the container body 101.
A gas passage chamber 107 is formed between the two.

[0004] The down tube 106 is provided with a coil spring 108.
The elastic seal member provided at the upper end thereof abuts against the inner wall of the bush 105 to constitute the gas valve 109. When the down tube 106 is pushed downward, the inside and outside of the barrel container communicate with each other. Has become. A beer valve 1 urged upward by a compression coil spring 110 is provided at the upper end of the down tube 106.
11 is provided, and when the beer valve 111 is pushed down, the upper end and the lower end of the down tube communicate with each other,
It has a structure in which beer can be injected into and out of the keg container.

[0005] As described above, the barrel container 100 is
02 and fitting 103, gas valve 1
09, the beer valve 111, the seal ring 104, etc., have a hermetically sealed structure so that the filling gas and beer do not leak inside. If the valve mechanism is deformed or cracks are formed in the welded portion or the like, a completely sealed state cannot be maintained and the quality of the content of beer is affected. For this reason, such barrels are inspected for leaks before filling with the contents.

As a method of inspecting the leak of the barrel, a visual inspection, a method of detecting a light leak using a lighting device, or a method of introducing a gas such as helium into the barrel and leaking the gas is used. There is a method of detecting leakage of a container by detecting the presence / absence of any of them, but all of these methods require labor and time for the operation, and have a problem in detection accuracy. Therefore, the present applicant has already developed and proposed a leak detecting device for a container using an ultrasonic measuring device (Japanese Patent Laid-Open No. 7-103844).
issue).

FIG. 8 shows an example of the leak detection device disclosed herein. The leak detection device 200 is provided in the middle of the transport path of the transport conveyor 101, and an inspection stopper 105 for stopping the barrel 100 transported to the inspection position is provided at the inspection position of the transport path. Upstream of the installation position of the leak inspection device 200, the barrel container 100
Is provided for stopping the operation.
The barrel container 100 conveyed to the leak detection position has its container opening washed with cleaning water in advance in a washing step. The barrel container 100 has the gas valve 109 of the fitting 103 shown in FIG. Open and compressed air is injected.

[0008] The leak detection device 200 includes a gantry 210, a lift cylinder 206 located below the transport conveyor 101 and pushing up the barrel container at the inspection position, and a gantry 2
The apparatus includes a box-shaped fixed sound insulation device 207 provided on the upper part of the apparatus 10 and a sound wave sensor 208 attached to the fixed sound insulation device 207. In the leak detection device 200, the barrel 100 conveyed to the inspection position is lifted by the lift cylinder 206 so that its mouth enters the fixed sound insulation device 207.

As the sound wave sensor 208, for example, an acoustic transducer such as a microphone or a piezo element is used. The generated ultrasonic waves are transmitted to the sound wave sensor 208 as shown in FIG.
The signal is picked up by an amplifier, converted into an electric signal, and amplified by a preamplifier 212.
13 is a predetermined frequency band, that is, a frequency band in which leak information of the barrel container is distributed is, for example, 36 kHz to 4 kHz.
It is selected to pass only 5 KHz. The leak information that has passed through the band pass filter 213 passes through a waveform shaper 214 and is counted by a frequency counter 215, sent to a frequency display unit 216, and sent to a level detection unit 217.
And the presence or absence of leakage is displayed on the display means 218.

[0010]

By the way, in the leak container detecting device using the leak detecting device based on the ultrasonic measurement, the leak of the pressurized gas filled in the container is detected by the ultrasonic wave. The detection is performed by a sensor, but in order to accurately detect the sound of the gas leak, it is necessary to accurately distinguish the sound generated by a cause other than the gas leak. For this reason, when detecting gas leakage from a container filled with a pressurized gas, means for accommodating the container in the sound insulation device and shutting off external sound is used as described above. However, even when the container is housed in the sound insulation device, a sound other than a gas leak may be generated, and if this is determined as a gas leak sound, an erroneous determination result will be given. For example, before entering the leak inspection, the container mouth is washed with the washing water, but when entering the leak inspection process, the washing water adheres to the container, and the attached water droplets drop and the sound of the dropping noise is generated. In some cases, this may be erroneously determined as a gas leak sound.

The present invention has been made in view of the above problems, and has as its object to provide a leak detection method and apparatus capable of accurately distinguishing the output detected from a sound wave sensor from noise caused by noise other than gas leak. It is an issue.

[0012]

According to the present invention, there is provided an object of the present invention for cutting out instantaneous noises generated in a sound insulation device accommodating an inspection container other than sounds caused by leakage such as sound of water drops. This solves the problem by accurately detecting gas leakage. According to a first aspect of the present invention, there is provided a container leak detection method for housing a container filled with a pressurized gas in a sound insulation space and detecting gas leakage by using a sound wave sensor to detect leak of the container. When the output from is higher than the reference level and continues for a predetermined period of time, it is determined that a leak has occurred in the container.

According to a second aspect of the present invention, there is provided means for accommodating a container filled with pressurized gas in a sound insulation space, and a sound wave sensor for detecting gas leakage from the container filled with pressurized gas contained in the sound insulation space. A leak detection device for a container that detects gas leak of the container by a sound wave sensor and detects leak of the container, wherein the leak detection device determines an output level of the sound wave sensor, a timer, and the sound wave. When the output of the sensor is equal to or higher than a predetermined level and continues for a predetermined time or more, a determination unit that determines that the container has a leak is provided.

According to each of the above-described aspects, it is possible to detect only a sound that continues for a predetermined time or more and cut off a sound that is instantaneously generated as noise. If there is a gas leak, the leak sound is generated continuously, and by cutting off the instantaneous sound, the gas leak can be detected accurately and the detection accuracy of the leak of the container is improved. This becomes possible.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a leak container detecting device in which a container leak detecting device according to an embodiment of the present invention is incorporated.
FIG. 1A is a plan view, and FIG. 1B is a front view. The leak container detecting device of the present embodiment is composed of four divided stations, and is composed of a standby station 1, a pressurizing station 2, an inspection station 3, and an evacuating station 4 in order from the loading side of the barrel 100. .

The stand-by station 1 is a stand-by state for starting a pressurizing step in the next pressurizing station 2. The stand-by station 1 makes the keg containers stand by until the pressurizing devices 21 to 23 of the pressurizing station become empty. It is a place to keep. A common conveyor 10 is provided between the standby station 1 and the pressurizing station in the next process, and a stopper 11 is installed near the conveyor of the standby station. The barrel container 100 to be prepared can be appropriately parked for a necessary time.

The pressurizing station 2 is a station for injecting pressurized gas into the barrel container as a preparation stage for leak inspection, and includes three pressurizing devices 21, 22, 23. Each pressure device 21 * (* is marked as representing 21 to 23)
As shown in FIG. 1B, a container holding device 24 is provided above the conveyor 10, and a pressurized gas filling device 25 is provided below the conveyor 10. The container holding device 24 converts the barrel 100 introduced with its mouth downward into a cylinder 24.
a, and is held down by a holding plate 24b driven by a. In addition, the gas filling device 25 includes the barrel container 1
No. 00 is filled with a pressurized gas, and is provided with a nozzle and a gas source which can be raised toward a container port located downward. The pressurizing station 2 is provided with a nozzle (not shown) for ejecting washing water at a container opening,
Before filling the cask container 100 with the pressurized gas, the mouth of the container is cleaned.

The inspection station 3 downstream of the pressurizing station has three leak inspection devices 31 arranged in series,
32 and 33 are provided. Each leak detecting device 31 * corresponds to the container leak detecting device of the present invention, and FIG.
It is the same in principle as the leak detection device described with reference to FIG. 10 and has a sound insulation device provided with a sound wave sensor. Each of the leak detection devices 31 * is connected to the conveyor 30
It has. The leak detection device 31 * also includes a sound insulation device 35 above. The sound insulation device 35 is supported by the gantry 24, and can be moved up and down by driving means 35a. As shown in FIG. 2, the sound insulation device 35 has a box-shaped structure, is made up of inner and outer boxes made of stainless steel and an inner sound insulation material, and has a plurality of sound wave sensors 36 attached to the wall. The signal processing detected by the sound wave sensor 36 will be described later in detail.

Each of the leak detecting devices 31 * also has a sound insulating table 37 provided with a conveyor. The sound detecting device 31 and the sound insulating table 37 form a sound insulating space by accommodating the loaded barrel 100 therein. I am trying to do it.
The rejection station 4 located downstream of the inspection station 3 sends a normal barrel container and a barrel container for which leakage has been detected based on the inspection result at the inspection station 3 to the regular transport path 4.
2 and a distributing device 41 for distributing the defective product to the defective product transport path 43. FIG. 3 shows a block circuit for processing a detection signal from the sound wave sensor 36.

The electric signal output from the sound wave sensor 36 is amplified by a preamplifier 50 and input to a waveform shaper 52 through a band pass filter 51. The band-pass filter 51 is selected so as to pass only from 36 KHz to 45 KHz, as in the case described above with reference to FIG. The waveform-shaped detection signal is subjected to processing described later in a microprocessor unit (MPU) 53, and it is determined whether or not the container has a leak based on the detection signal.
The determined result is input to, for example, the control unit of the sorting device 41 of the rejection station 4 and used for sorting containers.

FIG. 4 is output from the waveform shaping circuit 52.
An example of a waveform is shown. In this embodiment, one container
The inspection time T is set to 2 seconds. And detected
When the output signal is within the detection time T, the reference level S
If the time t exceeds the level,
Then a predetermined time t_s(In this example, we set it to 0.2 seconds.
The sound from the gas leak from the container
To determine that there is a leak in the container.
I have to. The predetermined time t_sIs a processing circuit operation professional
The setting value can be made variable by correcting the gram.
Wear. This time t _sIs the inspection speed, inspection equipment is located
The set value depending on the surrounding environment (especially ambient noise).
You. Therefore, in FIG.
Detection signals at inspection time (a), (b) and (c)
Is equal to or higher than the set reference level S.
It is less than the set 0.2 seconds, it is judged as noise
Not determined as a leak signal. Detection signal at next inspection time
(D) is a level S or more and 0.2 seconds or more
Therefore, it is regarded as a signal due to gas leakage, and if there is leakage in the container,
judge.

FIG. 5 shows a flow of a determination process performed by the MPU in the signal processing circuit shown in FIG. When the sound insulation box is lowered and the container to be inspected fits in the sound insulation box, the inspection by the sound wave sensor 36 is started, and the measurement of the inspection time T is started by the first timer built in the MPU (step S30).
0). Next, it is determined whether the output from the sensor 36 is higher than the set reference level S (step S30).
2). If it is determined that the level is higher than the reference level, a second timer built in the MPU is started, and a time t during which the level is high is measured (S304). If the time t is longer than the set time ts = 0.2 seconds, a leak is determined, a leak detection signal for the container is output (S308), and the process ends.

On the other hand, in step 306, when the detection time of the level high is shorter than the set value ts = 0.2 seconds,
It is determined whether the detection output is lower than the level S (S3).
10). If the level is low, the inspection time T
It is determined whether or not the time is within the set time Ts = 2 seconds (S312). If 2 seconds have elapsed, a normal determination signal is issued assuming that there is no leak in the container (S314). If the level is high in step 310, the process returns to step 306 again and the duration of the level high is counted.
In step 312, if it is within the inspection time,
Returning to step 302, the process is repeated during the inspection time Ts. If the output of the sound wave sensor is equal to or lower than the reference level S in step 202, the process of determining whether or not the inspection time is within the inspection time in step 313 is repeated. And
It ends.

As described above, in this embodiment, the output time of the sound wave sensor is measured at a predetermined level or more, and the gas leakage of the container is determined based on the output time. The noise of the instantaneous sound can be cut, and it is possible to prevent the erroneous determination of a normal container as a leaky container.

[0025]

As described above, according to the present invention, a gas leak from a container housed in a sound insulation device is detected by a sound wave sensor to detect a gas leak sound. Since the output time of the level is measured and the gas leak of the container is determined, the noise of the instantaneous sound due to the drop of the water drop from the container can be cut, and the leak of the normal container by mistake can be prevented. It is possible to prevent erroneous determination as a container having a defect.

[Brief description of the drawings]

FIG. 1 is a view showing a leaking container detecting device in which a leak detecting device for a container according to an embodiment of the present invention is used. (A) is a plan view, and (b) is a front view.

FIG. 2 is a diagram showing a sound insulation device of the leak detection device.

FIG. 3 is a block circuit diagram for performing signal processing from a sound wave sensor.

FIG. 4 is a diagram showing an output signal from a sound wave sensor.

FIG. 5 is a diagram showing a processing flow performed by a microprocessor.

FIG. 6 is an external view of a keg container for beer to be inspected.

FIG. 7 is a diagram illustrating details of a mouth portion of the barrel container.

FIG. 8 is a diagram showing a leak detection device using a conventional ultrasonic sensor.

FIG. 9 is a block diagram of a related art for processing a signal detected from a sound wave sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stand-by station 2 Pressurizing station 21-23 Pressurizing device 3 Inspection station 31-33 Leakage detecting device 35 Sound insulation device 36 Sound wave sensor 10, 30 Conveyor 4 Expulsion station 41 Sorting device

Claims (2)

[Claims] 1. A container leakage detection method for receiving a container filled with a pressurized gas in a sound insulation space and detecting gas leakage using a sound wave sensor to detect leakage of the container. A container leak detection method, wherein when the output is equal to or higher than a reference level and continues for a predetermined time, it is determined that a leak has occurred in the container. 2. A container for storing a container filled with pressurized gas in a sound insulation space, and a sound wave sensor for detecting gas leakage from the container filled with pressurized gas stored in the sound insulation space, In a container leak detection device that detects gas leakage with a sound wave sensor and detects leakage of the container, the leak detection device determines an output level of the sound wave sensor, a timing unit, and an output of the sound wave sensor is predetermined. A container leak detecting device, comprising: a judging means for judging that there is a leak in the container when the level is equal to or higher than a predetermined time.