JP5314387B2 - Leak detection system and leak detection method for sealed container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a leak detection system capable of substantially shortening the leak detection time when detecting the leak from a sealed container to be measured at a high temperature. <P>SOLUTION: The leak detection system 1 includes: leak inspection piping 2; a pressure setting means (pressure control valve 6 or the like) setting the pressure of an inspection space at a prescribed pressure different from the atmospheric pressure by allowing an inspection fluid to flow into the inspection space including the inside of the leak inspection piping 2 and the inside of the sealed container 100 to be measured connected to a terminal end of the leak inspection piping 2; and a leak determination means (determination unit 20) determining the presence of leak of the sealed container 100 to be measured on the basis of flow rate characteristics of the inspection fluid flowing through the inspection space after the prescribed pressure is set by the pressure setting means and flow rate characteristics when a reference sealed container without leak is connected in place of the sealed container 100 to be measured. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a leak detection system and a leak detection method for an airtight container.

  Conventionally, in various industrial fields, sealed containers have been used for the purpose of stabilizing and protecting contents. Such airtight containers may include those that cause air leaks due to poor sealing at the time of manufacture or damage to the container itself. For this reason, at present, various methods for detecting air leaks in a sealed container have been proposed.

  For example, a sealed container to be measured, which is a target for leak detection, is placed inside a leak detection chamber, the pressure inside the chamber is measured after the chamber is sealed, and the air leak in the measured sealed container is determined based on the change in the measured pressure. There has been proposed a so-called direct pressure type leak detection method for determining the presence or absence of a leak (see, for example, Patent Document 1). However, in such a direct pressure type leak detection method, accurate pressure detection is difficult because the pressure inside the chamber, which is a criterion for determination, is greatly influenced by changes in the measurement environment (for example, temperature and humidity outside the chamber). It may become.

In recent years, therefore, a leak detection method called a so-called differential pressure type has been proposed. In the differential pressure type leak detection method, two sealed tanks are connected through a pipe, a measured sealed container is placed inside one sealed tank, and the pressure inside both sealed tanks is set to be the same. This is a method of determining that an air leak has occurred in the sealed container to be measured when the pressure difference inside these two sealed tanks after a predetermined time has exceeded a predetermined threshold value. Such a differential pressure type leak detection method determines the presence or absence of an air leak based on the collapse of the pressure balance between the two sealed tanks, so that the leak detection result is not greatly affected by changes in the measurement environment. It is considered a thing.
JP 2005-99671 A

  However, when the differential pressure type leak detection method is employed to detect a leak in a closed container to be measured that has been heated to a high temperature, there are the following problems. When a high-temperature sealed container is placed inside the sealed tank, the measured sealed container is cooled during the leak judgment, and pressure fluctuations due to temperature changes of the measured sealed container occur inside the sealed tank. However, accurate pressure detection may be difficult due to this pressure fluctuation. For this reason, when performing leak detection on a heated container to be measured that has been heated, the high temperature container to be measured is cooled to room temperature, and the room temperature container to be measured is placed inside the sealed tank. Since it was necessary to perform leak detection by arranging the leak detector, it was difficult to reduce the leak detection time.

  The present invention has been made in view of such circumstances, and provides a leak detection system (method) capable of greatly reducing the leak detection time when performing leak detection of a high-temperature sealed container to be measured. With the goal.

  To achieve the above object, a first leak detection system according to the present invention has a leak of a first sealed container to be measured that has an opening and is sealed by a lid on the opening. A first detection space that is a detection system and includes a leak inspection pipe, an inside of the leak inspection pipe, and an inside of a first measured sealed container having an opening connected to the end of the leak inspection pipe. Pressure setting means for setting the pressure in the first inspection space to a predetermined pressure different from the atmospheric pressure by allowing the inspection fluid to flow in or out, and the flow rate of the inspection fluid flowing through the first inspection space A flow meter for detecting the flow rate, a flow rate characteristic of the flow rate detected by the flow meter after setting the predetermined pressure by the pressure setting means, and a flow rate characteristic when a leak-proof reference sealed container is connected instead of the first measured sealed container ,On the basis of the And leakage determination means determines the presence or absence of leakage of the first measured closed container, in which comprises a.

  The first leak detection method according to the present invention is a method for detecting a leak of a first measured closed container that has an opening and is sealed by a lid on the opening. Then, by connecting the opening of the first measured sealed container to the end of the leak testing pipe, the first inspection space including the inside of the leak testing pipe and the first measured sealed container is obtained. A first step of forming, and a second step of setting the pressure of the first inspection space to a predetermined pressure different from the atmospheric pressure by allowing the inspection fluid to flow into or out of the first inspection space. The flow characteristics of the inspection fluid flowing through the first inspection space after setting the predetermined pressure in the second step, and the flow characteristics when a leak-proof reference sealed container is connected instead of the first measured sealed container And based on the first measured sealed container A third step of determining whether the over-click, but with a.

  When such a configuration and method are employed, the flow rate characteristics of the inspection space after setting the predetermined pressure when the first measured closed container (for example, a container such as a PET bottle) sealed by the lid is connected to the leak inspection pipe, Based on the flow rate characteristic (reference flow rate characteristic) of the inspection space after setting the predetermined pressure when the reference closed container without leak is connected, the leak of the sealed container to be measured can be detected. It has been confirmed that the flow rate characteristic of the inspection space after setting the predetermined pressure when the measured sealed container is connected is substantially uniform even when the temperature of the measured sealed container changes. Therefore, by determining the presence or absence of a leak with reference to such flow characteristics, leak detection can be performed relatively accurately even with a heated high-temperature sealed container to be measured. As a result, the step of cooling the high-temperature sealed container to be measured to room temperature can be omitted, so that the leak detection time can be greatly shortened.

  The second leak detection system according to the present invention is a system for detecting a leak in a second sealed container to be measured that has been sealed in advance, and has an opening and a second sealed container to be measured inside. A second inspection space including a leak inspection chamber, a leak inspection pipe, an inside of the leak inspection pipe, and an inside of the leak inspection chamber having an opening connected to an end of the leak inspection pipe. On the other hand, the flow of the inspection fluid flowing through the second inspection space and the pressure setting means for setting the pressure of the second inspection space to a predetermined pressure different from the atmospheric pressure by flowing in or out the inspection fluid. A flow meter to detect, a flow rate characteristic of a flow rate detected by the flow meter after setting a predetermined pressure by the pressure setting means, and a flow rate characteristic in the case where a reference sealed container having no leak is arranged instead of the second measured sealed container, In Zui it is intended to include a leakage determination unit determines the presence or absence of leakage of the second measured closed container, the.

  A second leak detection method according to the present invention is a method for detecting a leak in a second measured sealed container that is sealed in advance, and the second measured sealed container is placed inside the leak test chamber. The first inspection space that includes the inside of the leak inspection pipe and the inside of the leak inspection chamber is formed by arranging and connecting the opening of the leak inspection chamber to the end of the leak inspection pipe. A step, a second step of setting the pressure of the second inspection space to a predetermined pressure different from the atmospheric pressure by allowing the inspection fluid to flow into or out of the second inspection space, and the second step On the basis of the flow characteristics of the inspection fluid flowing through the second inspection space after the predetermined pressure is set and the flow characteristics when a leak-free reference sealed container is arranged instead of the second measured sealed container , Second measured A third step of determining the presence or absence of leakage of the closed container, but with a.

  When such a configuration and method are employed, the flow rate of the inspection space after setting a predetermined pressure when a second sealed container to be measured (for example, a container such as a can) is placed inside the leak test chamber. Based on the characteristics and the flow rate characteristics (reference flow rate characteristics) of the inspection space after setting the predetermined pressure when a leak-free reference sealed container is arranged, it is possible to detect the leak of the measured sealed container. It has been confirmed that the flow rate characteristic of the inspection space after setting the predetermined pressure when the measured sealed container is connected is substantially uniform even when the temperature of the measured sealed container changes. Therefore, by determining the presence or absence of a leak with reference to such flow characteristics, leak detection can be performed relatively accurately even with a heated high-temperature sealed container to be measured. As a result, the step of cooling the high-temperature sealed container to be measured to room temperature can be omitted, so that the leak detection time can be greatly shortened.

  In the leak detection system, the time flow curve of the inspection fluid after setting the predetermined pressure by the pressure setting means is adopted as the flow characteristic, and the time flow curve when the measured sealed container is connected or arranged is connected to the reference sealed container. Alternatively, it is possible to employ a leak determination unit that determines that a leak has occurred in the sealed container to be measured when it is not included in the predetermined region centered on the time flow curve when arranged. As the time flow rate curve, one representing a time history of the instantaneous flow rate (integrated flow rate) of the test fluid from the time when the pressure of the test space is set to a predetermined pressure by the pressure setting means can be adopted.

  Further, in the leak detection system, the instantaneous flow rate (integrated flow rate) of the inspection fluid when a predetermined time elapses from the time when the pressure of the inspection space is set to the predetermined pressure by the pressure setting means is adopted as the flow characteristic, If the instantaneous flow rate (integrated flow rate) when the container is connected or arranged is not included in the specified flow range centered on the instantaneous flow rate (integrated flow rate) when the reference sealed container is connected or arranged, the measured sealed container Leak determination means for determining that a leak has occurred may be employed.

  The leak detection system may further include determination result output means for outputting the presence / absence of the leak determined by the leak determination means as a signal.

  When such a configuration is adopted, the user can confirm whether there is a leak in the sealed container to be measured.

  In the leak detection system, a thermal flow meter can be employed as the flow meter. Also, a flow sensor that includes a substrate having a recess on at least one surface and a detection element bridged on the recess of the substrate and detects a flow rate or a flow rate of the fluid based on a temperature change of the detection element. A thermal flow meter can be employed.

  When such a configuration is adopted, the flow rate characteristic can be detected by using a thermal flow meter that employs a flow sensor that has a configuration capable of high-speed response and capable of being on the flow meter side in a low-pressure environment. Therefore, it is possible to determine the presence or absence of leakage in the sealed container to be measured very accurately.

  According to the present invention, it is possible to provide a leak detection system (method) capable of greatly reducing the leak detection time when performing leak detection of a high-temperature sealed container to be measured.

  Hereinafter, a leak detection system according to an embodiment of the present invention will be described with reference to the drawings.

[First embodiment]
As a first embodiment of the present invention, a leak of a first measured sealed container (hereinafter referred to as a “first sealed container”) such as a PET bottle configured to be sealed with a lid on an opening is detected. The leak detection system 1 will be described. First, the configuration of the leak detection system 1 according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 1, the leak detection system 1 includes a leak inspection pipe 2 and a shutoff valve 3 for shutting off air (inspection fluid) supplied to the leak inspection pipe 2 from an air supply source (not shown). The flow meter 4, the pressure sensor 5, the pressure control valve 6, and the bypass pipe 7 connected to the leak inspection pipe 2 to bypass the pressure control valve 6 are provided in the leak inspection pipe 2. The initial supply mass flow controller 8, the buffer tank 9, various devices in the system, and a determination device 20 that determines whether there is a leak in the first sealed container 100 are provided.

  The opening / closing operation of the shut-off valve 3 is controlled by the determiner 20. When the shut-off valve 3 is closed, a closed space (hereinafter referred to as “first inspection space”) is formed by the inside of the pipe (the leak inspection pipe 3 and the bypass pipe 7) and the inside of the first sealed container 100. It will be. The determiner 20 detects a leak in the first sealed container 100 based on the air flow in the first inspection space.

  The flow meter 4 detects the flow rate of air flowing through the first inspection space. Information on the flow rate detected by the flow meter 4 is transmitted to the determiner 20 and used for leak determination. The flow meter 4 in the present embodiment is a thermal flow meter having a thermal flow sensor having a semiconductor diaphragm. Here, the configuration of the thermal flow sensor 40 will be described with reference to FIGS. 2 and 3.

  2 and 3, the thermal flow sensor 40 includes a substrate 41 provided with a cavity 42 (concave portion), an insulating film 43 disposed on the substrate 41 so as to cover the cavity 42, and an insulating film 43. It has a heater 44 provided, a first resistance temperature sensor 45 and a second resistance resistance element 46 disposed on both sides of the heater 44, an ambient temperature sensor 47, and the like.

  The portion of the insulating film 43 covering the cavity 42 constitutes a heat insulating diaphragm. The ambient temperature sensor 47 measures the temperature of air in the first examination space. The heater 44 is disposed at the center of the insulating film 43 covering the cavity 42, and heats the air flowing through the first inspection space so that the temperature is higher than the temperature measured by the ambient temperature sensor 47. The first temperature measuring resistance element 45 functions as a detection element that detects the temperature on one side of the heater 44, and the second temperature measurement resistance element 46 functions as a detection element that detects the temperature on the other side of the heater 44.

  Here, when the air in the first examination space is stationary, the heat applied by the heater 44 diffuses symmetrically to both sides of the heater 44. Accordingly, the temperatures of the first temperature measuring resistance element 45 and the second temperature measuring resistance element 46 are equal, and the electric resistances of the first temperature measuring resistance element 45 and the second temperature measuring resistance element 46 are equal. On the other hand, when the air in the first examination space flows in the direction of the arrow shown in FIGS. 2 and 3, for example, the heat applied by the heater 44 is downstream of the second temperature measuring resistance element 46. Carried to the side. Accordingly, the temperature of the second resistance thermometer element 46 becomes higher than the temperature of the first resistance thermometer element 45, and thereby the electric resistance of the first resistance thermometer element 45 and the second resistance thermometer resistance There is a difference between the electrical resistance of the element 46.

  The difference between the electrical resistance of the first resistance temperature sensor 45 and the electrical resistance of the second resistance temperature sensor 46 has a correlation with the flow velocity and flow rate of air in the first examination space. For this reason, the flow velocity and flow rate of the air flowing through the first inspection space are calculated from the difference between the electrical resistance of the first resistance temperature sensor 45 and the electrical resistance of the second resistance temperature sensor 46. Even when air flows in the direction opposite to the direction of the arrows shown in FIGS. 2 and 3, the flow velocity and flow rate of the air can be calculated based on the same principle.

As a material of the substrate 41 shown in FIGS. 2 and 3, silicon (Si) or the like can be used. As a material of the insulating film 43, silicon oxide (SiO ₂ ) or the like can be used. The cavity 42 is formed by anisotropic etching or the like. Further, platinum (Pt) or the like can be used for each material of the heater 44, the first temperature measuring resistance element 45, the second temperature measuring resistance element 46, and the ambient temperature sensor 47, and can be formed by a lithography method or the like. .

  The pressure sensor 5 is provided at a position upstream of the flow meter 4 of the leak test pipe 2 and detects the pressure of the air flowing through the leak test pipe 2. Information related to the pressure detected by the pressure sensor 5 is transmitted to the determination device 20 and used for controlling the pressure control valve 6. The pressure control valve 6 controls the pressure of the air flowing through the leak inspection pipe 2 by the opening / closing operation of the pressure control valve 6 being controlled by the determiner 20. As the pressure control valve 6, a small flow rate control mass flow controller (which controls a small flow rate as compared with the initial supply mass flow controller 8) can be adopted.

  The bypass pipe 7 is for leading the air supplied from the air supply source to the first sealed container 100 without passing through the pressure control valve 6 and is used in the initial stage of air supply. The initial supply mass flow controller 8 adjusts the flow rate of the air supplied from the air supply source, and is controlled by the determiner 20. In the present embodiment, the initial supply mass flow controller 8 is used to supply a predetermined flow rate of air so that the pressure in the first examination space reaches an approximate target value close to a predetermined target value, and then the pressure control valve 6. Is used to control the pressure in the first examination space to reach a predetermined target value.

  The buffer tank 9 is disposed on the downstream side of the pressure control valve 6 of the leak inspection pipe 2. By storing a large volume of air inside the buffer tank 9, the pressure in the inspection space after setting a predetermined pressure is caused by the leak. It functions to suppress a sudden drop (buffer function) and contributes to improving the accuracy of leak inspection. In addition, the buffer tank 9 also functions to suppress the occurrence of hunting during pressure control by the pressure control valve 6. Further, in the present embodiment, the supercharging countermeasure mass flow controller 10 is provided for the purpose of preventing an excessive increase in the pressure inside the first sealed container 100 due to an excessive supply of air from the air supply source. Adopted. The supercharging countermeasure mass flow controller 10 is provided in a branch pipe 11 that branches from a position downstream of the pressure control valve 6 of the leak inspection pipe 3. When a large amount of air is introduced from the air supply source, the supercharging countermeasure mass flow controller 10 is operated by the control of the determination unit 20 so that the pressure inside the first sealed container 100 is suppressed to a predetermined threshold value or less. It has become.

As shown in FIG. 1, the determiner 20 includes a central control unit 21 that controls various devices and information processing, a memory 22 that records various information such as detection results and determination results, and various information such as determination results and alarms. It has a display unit 23 for displaying, an operation unit 24 for inputting various types of information regarding determination, and the like. The memory 22 stores various data (for example, data such as a time-flow curve C ₀ described later) used for determining the leak of the first sealed container 100. The display unit 23 outputs a leak determination result (presence or absence of leak) as image information, and functions as a determination result output unit in the present invention.

  Prior to the leak determination process of the first sealed container 100, the central control unit 21 controls the initial supply mass flow controller 8 and the pressure control valve 6 so that the pressure in the first examination space is higher than the atmospheric pressure by a predetermined pressure (predetermined). Target value). Specifically, the central control unit 21 controls the initial supply mass flow controller 8 so as to cause a predetermined flow rate of the inspection fluid to flow into the first inspection space, whereby the pressure detected by the pressure sensor 5 is set to the target value. To a predetermined approximate target value close to. Then, the central control unit 21 controls the pressure control valve 6 from the time when the pressure detected by the pressure sensor 5 reaches the approximate target value, thereby causing the pressure detected by the pressure sensor 5 to reach the target value. The shut-off valve 3 is closed. The determination device 20 (central control unit 21), the initial supply mass flow controller 8 and the pressure control valve 6 constitute pressure setting means in the present invention.

Further, the central control unit 21 has a flow rate characteristic of the flow rate detected by the flow meter 4 and a reference flow rate characteristic when a leak-free reference sealed container is connected to the leak inspection pipe 2 instead of the first sealed container 100. Based on the above, the presence or absence of leakage of the first sealed container 100 is determined. That is, the central control unit 21 functions as a leak determination unit in the present invention. In the present embodiment, as a flow rate characteristic, a temporal flow rate curve as shown in FIG. 4 (the instantaneous flow rate of air flowing through the first examination space after the pressure in the first examination space is set to the predetermined pressure P _0). The curve representing the time history of the

The time flow rate curve C ₀ (reference flow rate characteristic) when a leak-free reference sealed container is connected to the leak inspection pipe 2 is as shown in FIG. 4 when a predetermined time elapses from the leak determination start time (t ₁ ). At (t ₂ ), it converges to a straight line with zero flow rate. On the other hand, as shown in FIG. 4, the time-flow curve C _L in the case where a leaked sealed container to be measured is connected to the leak inspection pipe 2 shows that even if a predetermined time elapses from the leak determination start time (t ₁ ). Does not converge to a straight line with zero flow rate. Therefore, in the present embodiment, a specific area A ₀ (area shown by hatching in FIG. 4) centered on the time flow curve C ₀ corresponding to the reference sealed container is set, and from the leak determination start time (t ₁ ). It is determined that a leak has occurred in the first sealed container 100 when the time-flow curve corresponding to the first sealed container 100 is not included in the specific area A ₀ at the time point (t ₂ ) after the predetermined time has elapsed. It is said.

Experiments have shown that the time-flow curve used in this leak judgment does not depend on the temperature of the sealed container to be leaked (ie, it has a constant shape regardless of the temperature of the sealed container to be measured). Yes. Therefore, when the leak determination is performed using such a time flow curve, the leak determination time can be significantly shortened (for example, the leak determination is performed within the times t _{1 to} t ₂ shown in FIG. 4). Become.

The time pressure curve (curve representing the time history of the pressure in the first examination space after the pressure in the first examination space is set to the predetermined pressure P ₀ ) shown in FIG. 4 will be described. When a leak-free reference sealed container is connected to the leak inspection pipe 2, the pressure in the first inspection space is substantially constant even when a predetermined time elapses (t ₂ ) from the leak determination start time (t ₁ ). Maintained at the value. For this reason, as shown in FIG. 4, the time pressure curve C _P0 in the case of connecting a reference closed container without leak does not _deviate greatly from the straight line of the pressure P ₀ even if a predetermined time elapses from the leak determination start time. . On the other hand, when a leaked sealed container to be measured is connected to the leak inspection pipe 2, the pressure in the first inspection space gradually decreases from the leak determination start time (t ₁ ). Therefore, as shown in FIG. 4, the time pressure curve C _PL when a leaked measurement sealed container is connected gradually departs from the straight line of the pressure P _{0 when} a predetermined time elapses from the leak determination start time. It will be.

  Next, a leak detection method according to the present embodiment (a method for detecting a leak in the first sealed container 100 using the leak detection system 1) will be described using the flowchart of FIG.

First, the opening part 110 of the 1st airtight container 100 is connected to the terminal 2a of the leak inspection piping 2 of the leak detection system 1 (airtight container connection process: S1). Next, the central control unit 21 of the determination device 20 of the leak detection system 1 controls the initial supply mass flow controller 8 and the pressure control valve 6 based on the operation of the operation unit 24 by the user and the like, thereby performing the first inspection. Air is introduced into the space, and the pressure in the first examination space is set to a predetermined pressure P ₀ higher than atmospheric pressure (pressure setting step: S2). In the pressure setting step S2, the central control unit 21 controls the initial supply mass flow controller 8 in the initial stage of air supply (from the air supply start time t ₀ shown in FIG. 4 to a time t ₀ ′ after a predetermined time has elapsed). As a result, a predetermined flow rate of air is supplied to cause the pressure in the first examination space to reach a predetermined approximate target value. Thereafter, the central control unit 21 performs the fine adjustment of the pressure by controlling the pressure control valve 6 in the final stage (from the time point t ₀ ′ shown in FIG. 4 to the leak determination start time point t ₁ ) to perform the first adjustment. The pressure in the inspection space is made to reach the target value (predetermined pressure P ₀ ).

Subsequently, the central control unit 21 of the determiner 20 of the leak detection system 1 determines the air flow characteristics (first sealed container) in the first examination space detected by the flow meter 4 based on the operation of the operation unit 24 or the like. (Time flow rate curve corresponding to 100) and a reference flow rate characteristic when a reference airtight container without leak is connected instead of the first airtight container 100, the presence or absence of leakage of the first airtight container 100 is determined ( Leak determination step: S3). In the leak determination step S3, the central control unit 21 determines that the time flow rate curve corresponding to the first sealed container 100 corresponds to the reference sealed container at the time (t ₂ ) when a predetermined time has elapsed from the leak determination start time (t ₁ ). When it is not included in the specific area A ₀ (FIG. 4) centering on the time flow curve C ₀ to be determined, it is determined that a leak has occurred in the first sealed container 100.

  Thereafter, the central controller 21 of the determiner 20 displays the presence / absence of the leak determined in the leak determination step S3 on the display unit 23 based on the operation of the operation unit 24 (determination result display step: S4), Complete all steps. The sealed container connection step S1, the pressure setting step S2, and the leak determination step S3 correspond to the first step, the second step, and the third step in the present invention, respectively.

  In the leak detection system 1 according to the embodiment described above, the flow rate of the first inspection space after setting a predetermined pressure when the first sealed container 100 (for example, a container such as a PET bottle) sealed by the lid is connected. It is possible to detect a leak of the first sealed container 100 based on the characteristics and the flow characteristic (reference flow characteristic) of the first inspection space after setting the predetermined pressure when a reference closed container without leak is connected. it can. It has been confirmed that the flow rate characteristic of the first inspection space after setting the predetermined pressure when the measured sealed container is connected is substantially uniform even when the temperature of the measured sealed container changes. Therefore, by determining the presence or absence of a leak with reference to such a flow rate characteristic, leak detection can be performed relatively accurately even with the heated high-temperature first sealed container 100. As a result, the step of cooling the high temperature first sealed container 100 to room temperature can be omitted, and the leak detection time can be greatly shortened.

  Further, in the leak detection system 1 according to the embodiment described above, since the leak determination result of the first sealed container 100 can be displayed on the display unit 23, the user confirms whether there is a leak in the first sealed container 100. can do.

  Further, in the leak detection system 1 according to the above-described embodiment, it is necessary for the leak determination using the flow meter 4 having the thermal flow sensor 40 capable of high-speed response and capable of the flow meter side in a low pressure environment. Since the flow rate of the first inspection space is detected, the presence or absence of a leak in the first sealed container 100 can be determined very accurately.

[Second Embodiment]
As a second embodiment of the present invention, a description will be given of a leak detection system 1A for detecting a leak of a second measured sealed container (hereinafter referred to as “second sealed container”) such as a canned can that has been sealed in advance. To do. The leak detection system 1A according to the present embodiment has a leak inspection chamber 12 connected to the end of the leak inspection pipe 2 of the leak detection system 1 according to the first embodiment, and other configurations are the first embodiment. Is substantially the same. For this reason, about the overlapping structure, the same code | symbol as 1st Embodiment is attached | subjected and suppose that detailed description is abbreviate | omitted.

  As shown in FIG. 6, the leak detection system 1 </ b> A according to the present embodiment includes a leak inspection pipe 2, a leak inspection chamber 12 connected to the end 2 a of the leak inspection pipe 2, and a second sealed container 200. And a determiner 20A that determines whether or not there is a leak. The leak detection system 1A includes a shutoff valve 3, a flow meter 4, a pressure sensor 5, a pressure control valve 6, an initial supply mass flow controller 8, a buffer tank 9, and a supercharging countermeasure mass flow controller 10. The configuration is substantially the same as that described in the first embodiment.

  The leak test chamber 12 is a sealed tank for housing the second sealed container 200 therein, and has an opening 13 connected to the end 2 a of the leak test pipe 2. When the shut-off valve 3 is closed, a closed space (hereinafter referred to as “second inspection space”) is formed by the inside of the pipe (the leak inspection pipe 3 or the bypass pipe 7) and the inside of the leak inspection chamber 12. The Rukoto. The determiner 20A detects a leak in the second sealed container 200 based on the air flow in the second inspection space.

  As shown in FIG. 6, the determination unit 20A includes a central control unit 21A that controls various devices and information processing, a memory 22A that records various information such as detection results and determination results, and various information such as determination results and alarms. It has a display unit 23A for displaying, an operation unit 24A for inputting various information related to determination, and the like, and the basic configuration is common to the determination unit 20 of the first embodiment. Various data used for the leak determination of the second sealed container 200 are stored in the memory 22A.

  Prior to the leak determination process of the second sealed container 200, the central control unit 21A controls the initial supply mass flow controller 8 and the pressure control valve 6 to set the pressure in the second inspection space to a predetermined target value. Specifically, the central control unit 21A controls the initial supply mass flow controller 8 so that a predetermined flow rate of air flows into the second inspection space, whereby the pressure detected by the pressure sensor 5 is close to the target value. A predetermined approximate target value is reached. Then, the central control unit 21A controls the pressure control valve 6 from the time when the pressure detected by the pressure sensor 5 reaches the approximate target value, thereby causing the pressure detected by the pressure sensor 5 to reach the target value. The shut-off valve 3 is closed. The determination device 20A (central control unit 21A), the initial supply mass flow controller 8 and the pressure control valve 6 constitute pressure setting means in the present invention.

  Further, the central control unit 21A has a flow rate characteristic of the flow rate detected by the flow meter 4 and a reference flow rate characteristic when a leak-free reference sealed container is disposed inside the leak test chamber 12 instead of the second sealed container 200. Based on the above, the presence or absence of leakage of the second sealed container 200 is determined. That is, the central control unit 21A functions as a leak determination unit in the present invention. As in the first embodiment, the central control unit 21A in the present embodiment includes a time flow curve (reference flow characteristics) when a leak-free reference sealed container is disposed inside the leak inspection chamber 12, and a second sealed container. Based on the time flow curve corresponding to 200, the leak determination of the second sealed container 200 is performed.

  Next, a leak detection method according to the present embodiment (a method for detecting a leak in the second sealed container 200 using the leak detection system 1A) will be described with reference to the flowchart of FIG.

  First, the second sealed container 200 is disposed inside the leak test chamber 12 of the leak detection system 1A, and the opening 13 of the leak test chamber 12 is connected to the end 2a of the leak test pipe 2 (closed container placing step). : S11). Next, the central control unit 21A of the determination device 20A of the leak detection system 1A performs the second inspection by controlling the initial supply mass flow controller 8 and the pressure control valve 6 based on the operation of the operation unit 24A by the user. Air is introduced into the space, and the pressure in the second inspection space is set to a predetermined pressure higher than the atmospheric pressure (pressure setting step: S12). In the pressure setting step S12, the central control unit 21A supplies a predetermined flow rate of air using the initial supply mass flow controller 8 in the initial stage of air supply to reach the predetermined approximate target value of the pressure in the second inspection space. Thereafter, the pressure in the second inspection space is made to reach the target value (predetermined pressure) by finely adjusting the pressure using the pressure control valve 6 in the final stage.

  Subsequently, the central control unit 21A of the determination unit 20A of the leak detection system 1A determines the air flow characteristics (second sealed container) in the second examination space detected by the flow meter 4 based on the operation of the operation unit 24A and the like. (Time flow rate curve corresponding to 200) and a reference flow rate characteristic in the case where a reference airtight container having no leak is arranged instead of the second airtight container 200, the presence or absence of leakage of the second airtight container 200 is determined ( Leak determination step: S13). Thereafter, the central control unit 21A of the determiner 20A displays the presence / absence of the leak determined in the leak determination step S13 on the display unit 23A based on the operation of the operation unit 24A (determination result display step: S14), Complete all steps. The sealed container arrangement step S11, the pressure setting step S12, and the leak determination step S13 correspond to the first step, the second step, and the third step in the present invention, respectively.

  In the leak detection system 1A according to the embodiment described above, the flow rate of the second inspection space after setting the predetermined pressure when the second sealed container 200 (for example, a container such as a canned can) that is sealed in advance is disposed. It is possible to detect a leak of the second sealed container 200 based on the characteristics and the flow characteristic (reference flow characteristic) of the second inspection space after setting the predetermined pressure when the reference closed container without leak is arranged. it can. It has been confirmed that the flow rate characteristic of the second inspection space after setting the predetermined pressure when the measured sealed container is connected is substantially uniform even when the temperature of the measured sealed container changes. Therefore, by determining the presence or absence of a leak with reference to such flow characteristics, leak detection can be performed relatively accurately even with the heated high-temperature second sealed container 200. As a result, since the process of cooling the high temperature second sealed container 200 to room temperature can be omitted, the leak detection time can be greatly shortened.

  Further, in the leak detection system 1A according to the embodiment described above, since the leak determination result of the second sealed container 200 can be displayed on the display unit 23, the user confirms whether there is a leak in the second sealed container 200. can do.

  Further, in the leak detection system 1A according to the embodiment described above, it is necessary for the leak determination using the flow meter 4 having the thermal flow sensor 40 capable of high-speed response and capable of the flow meter side in a low pressure environment. Since the flow rate of the second inspection space is detected, the presence or absence of leakage in the second sealed container 200 can be determined very accurately.

  In each of the above embodiments, an example in which one shutoff valve 3 is provided on the upstream side of the buffer tank 9 has been shown, but on the downstream side of the buffer tank 9 (between the buffer tank 9 and the object to be measured). Can be provided with a second shut-off valve (or other fluid shut-off mechanism). Then, prior to removing the first sealed container 100 or the leak test chamber 12 from the end 2a of the leak test pipe 2 when replacing the object to be measured, the second shut-off valve is used to supply the test fluid. Supply can be stopped. As the second shut-off valve, for example, a mass flow controller provided instead of the flow meter 4 can be employed.

  Thus, when the supply of the inspection fluid is stopped using the second shut-off valve when the object to be measured is replaced, the outflow of the inspection fluid from the leakage inspection pipe 2 can be stopped to a small amount. A pressure drop inside the inspection pipe 2 can be suppressed. When restarting the leak inspection after exchanging the object to be measured, the second shut-off valve is opened and the inspection fluid is supplied again, and at the same time, the pressure control valve 6 and the initial supply mass flow controller 8 are used. By controlling the pressure, the pressure in the examination space can reach the target value in a very short time. Accordingly, the supply time of the inspection fluid after the object to be measured can be greatly reduced, so that the inspection time when performing a leak inspection of a plurality of different objects to be measured can be greatly reduced. Become.

  Further, in each of the above embodiments, an example has been shown in which a leak test is performed in a state where the shut-off valve 3 is closed and a closed space is formed, but in a state where the shut-off valve 3 is not closed (that is, supply of the inspection fluid) Leak inspection can also be performed. As described above, when the leak inspection is performed while the supply of the inspection fluid is continued, the buffer tank 9 can be omitted.

  Further, in each of the above embodiments, the example in which the supply of the inspection fluid is stopped using the shut-off valve 3 has been shown. However, the supply of the inspection fluid using the pressure control valve 6 and the initial supply mass flow controller 8 is shown. Can also be stopped. Further, a mass flow controller (hereinafter referred to as “third mass flow controller”) is adopted as the pressure control valve 6, and the supply of the inspection fluid is stopped using the third mass flow controller and the initial supply mass flow controller 8. Also good.

  Further, in each of the above embodiments, an example was shown in which a predetermined flow rate of air was introduced into the inspection space, and the leak inspection was performed after setting the pressure of the inspection space to a predetermined pressure higher than the atmospheric pressure. It is also possible to carry out a leak inspection after flowing a predetermined flow rate of air from the inspection space and setting the pressure in the inspection space to a predetermined pressure lower than the atmospheric pressure.

  Further, in each of the above embodiments, an example is shown in which a curve representing a time history of “instantaneous flow rate” of air flowing through the examination space after setting a predetermined pressure is adopted as a time flow rate curve. A curve representing a time history of “integrated flow rate” of air flowing through the examination space after setting a predetermined pressure may be adopted as the time flow rate curve.

In each of the above embodiments, the time flow curve corresponding to the measured sealed container has a specific region (A ₀ in FIG. 4) centered on the time flow curve (C ₀ in FIG. 4) corresponding to the reference sealed container. However, the leak determination method is not limited to this.

For example, the “instantaneous flow rate” of air at a predetermined time (for example, t ₃ in FIG. 4) when the measured sealed container is connected or arranged is “the instantaneous flow rate” of the air at the predetermined time when the reference sealed container is connected or arranged. When it is not included in the predetermined flow rate range (ΔQ in FIG. 4) centering on “instantaneous flow rate”, it can be determined that a leak has occurred in the sealed container to be measured. Also, the “integrated flow rate” of air at a predetermined time when the measured sealed container is connected or arranged is a predetermined value centered on the “integrated flow rate” of air at the predetermined time when the reference sealed container is connected or arranged. When not included in the flow rate range, it may be determined that a leak has occurred in the sealed container to be measured. Further, the time derivative at a predetermined time point (for example, t ₂ in FIG. 4) of the time flow curve corresponding to the sealed container to be measured is compared with the time derivative at the predetermined time point of the time flow curve corresponding to the reference sealed container. When the difference between the two exceeds a predetermined threshold value, it can be determined that a leak has occurred in the sealed container to be measured.

  Moreover, in this embodiment, although the example which employ | adopted the thermal type flowmeter provided with the thermal type flow sensor which has a semiconductor diaphragm as a flow meter was shown, it replaced with this thermal type flow sensor, and another system (ultrasonic type) was shown. Or an electromagnetic type) may be employed. In addition, the present invention can be variously modified and implemented without departing from the scope of the invention.

It is a block diagram which shows the structure of the leak detection system which concerns on 1st Embodiment of this invention. It is a perspective view which shows the flow sensor of the flowmeter of the leak detection system shown in FIG. FIG. 3 is an end view of the flow sensor of FIG. 2 when viewed from the III-III direction. It is a graph for demonstrating the time flow rate curve used for the leak determination of the leak detection system shown in FIG. It is a flowchart for demonstrating the leak detection method which concerns on 1st Embodiment of this invention. It is a block diagram which shows the structure of the leak detection system which concerns on 2nd Embodiment of this invention. It is a flowchart for demonstrating the leak detection method which concerns on 2nd Embodiment of this invention.

Explanation of symbols

1.1A ... Leak detection system 2 ... Pipe for leak inspection 2a ... Terminal 4 ... Flow meter 6 ... Pressure control valve (pressure setting means)
8 ... Mass flow controller for initial supply (pressure setting means)
DESCRIPTION OF SYMBOLS 12 ... Chamber for leak inspection 13 ... Opening part 20 * 20A ... Determination device (Pressure setting means, leak determination means)
23.23A. Display section (judgment result output means)
40 ... thermal flow sensor 41 ... substrate 42 ... cavity (recess)
45... First temperature measuring resistance element (detection element)
46: Second temperature measuring resistance element (detection element)
100: 1st airtight container (1st airtight container to be measured)
110: opening 200 ... second sealed container (second measured sealed container)

Claims (9)

A system for detecting a leak in a first measured sealed container that has an opening and is configured to be sealed by applying a lid to the opening,
Piping for leak inspection;
An inspection fluid flows into a first inspection space including the inside of the leak inspection pipe and the inside of the first measured sealed container having the opening connected to the end of the leak inspection pipe, or A pressure setting means for setting the pressure in the first examination space to a predetermined pressure different from the atmospheric pressure by flowing out;
A flow meter for detecting a flow rate of the inspection fluid flowing through the first inspection space;
Based on the flow rate characteristic of the flow rate detected by the flowmeter after the predetermined pressure setting by the pressure setting means, and the flow rate characteristic in the case of connecting a reference closed vessel without leak instead of the first measured closed vessel Leak determining means for determining whether or not there is a leak in the first measured sealed container ,
Wherein as a flow characteristic, time flow curve of the test fluid in the predetermined pressure setting after by the pressure setting means Ru is employed,
A leak detection system for sealed containers. A system for detecting a leak in a second sealed container to be measured that is sealed in advance,
A leak inspection chamber having an opening and having the second sealed container to be measured disposed therein;
Piping for leak inspection;
An inspection fluid is allowed to flow into or out of a second inspection space including the inside of the leak inspection pipe and the inside of the leak inspection chamber having the opening connected to the end of the leak inspection pipe. The pressure setting means for setting the pressure in the second inspection space to a predetermined pressure different from the atmospheric pressure,
A flow meter for detecting a flow rate of the inspection fluid flowing through the second inspection space;
Based on the flow rate characteristics of the flow rate detected by the flow meter after the predetermined pressure setting by the pressure setting means, and the flow rate characteristics in the case where a reference sealed container without leak is arranged instead of the second measured sealed container And a leak determination means for determining whether there is a leak in the second measured sealed container ,
Wherein as a flow characteristic, time flow curve of the test fluid in the predetermined pressure setting after by the pressure setting means Ru is employed,
A leak detection system for sealed containers. The leakage determination unit, when the time rate curve in the case where the pre-Symbol measured closed container connected or arranged is not included in a predetermined region around the time flow curve in case of connecting or arranging the reference sealed container Determining that a leak has occurred in the measured sealed container,
The leak detection system of the airtight container of Claim 1 or 2. The time flow curve represents a time history of the instantaneous flow rate of the inspection fluid from the time when the pressure of the inspection space is set to the predetermined pressure by the pressure setting means.
The leak detection system of the airtight container of Claim 3. The time flow rate curve represents a time history of the integrated flow rate of the inspection fluid from the time when the pressure of the inspection space is set to the predetermined pressure by the pressure setting means.
The leak detection system of the airtight container of Claim 3. A determination result output means for outputting as a signal the presence or absence of a leak determined by the leak determination means;
The leak detection system of the airtight container as described in any one of Claim 1 to 5 . The flow meter is a thermal flow meter,
The thermal flow meter includes a substrate having a recess on at least one surface thereof, and a detection element bridged on the recess of the substrate, and a fluid flow rate or flow rate based on a temperature change of the detection element. Having a flow sensor for detecting,
The leak detection system of the airtight container as described in any one of Claim 1 to 6 . A method of detecting a leak of a first sealed container to be measured configured to have an opening and to be sealed by a lid on the opening,
A first inspection including the inside of the leak inspection pipe and the inside of the first measured airtight container by connecting the opening of the first airtight container to be measured to the end of the leak inspection pipe. A first step of forming a space;
A second step of setting the pressure of the first inspection space to a predetermined pressure different from the atmospheric pressure by flowing an inspection fluid into or out of the first inspection space;
When the flow rate characteristic of the inspection fluid flowing through the first inspection space after the predetermined pressure is set in the second step and a reference closed container that does not leak in place of the first measured closed container are connected A third step of determining the presence or absence of leakage of the first sealed container to be measured based on the flow rate characteristic in
As the flow properties, we adopt time flow curve of the test fluid after the predetermined pressure set by the pressure setting means,
A method for detecting leaks in sealed containers. A method of detecting a leak in a second sealed container to be measured that has been sealed in advance,
The second sealed container to be measured is disposed inside the leak test chamber, and an opening of the leak test chamber is connected to the end of the leak test pipe to thereby connect the inside of the leak test pipe and the leak A first step of forming a second inspection space including the inside of the inspection chamber;
A second step of setting the pressure of the second inspection space to a predetermined pressure different from the atmospheric pressure by flowing an inspection fluid into or out of the second inspection space;
When a flow rate characteristic of the inspection fluid that circulates in the second inspection space after setting the predetermined pressure in the second step, and a reference closed container that does not leak in place of the second measured closed container And a third step of determining the presence or absence of leakage of the second sealed container to be measured based on the flow rate characteristics in
As the flow properties, we adopt time flow curve of the test fluid after the predetermined pressure set by the pressure setting means,
A method for detecting leaks in sealed containers.

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