JP2010107452A - Leak detection system and method for sealed container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a leak detection system capable of substantially shortening the time period in which a sealed container to be measured as a leak detection object is exposed to a high-pressure or a low-pressure. <P>SOLUTION: The system 1 detects the leak from the sealed container 100 to be measured by allowing an inspection fluid to flow into an inspection space including the inside of the sealed container 100 to be measured and the inside of leak inspection piping 2 connected to the sealed container 100 to be measured to set a pressure in the inspection space at a prescribed target value different from the atmospheric pressure. The system includes: a flow rate control means (central control part 21) allowing the pressure in the inspection space at a prescribed approximate target value close to the target value by controlling in a mass flow controller 8 so that a prescribed flow rate of the inspection fluid flows into the inspection space; and a pressure control means (central control part 21) allowing the pressure of the inspection space to reach the target value by controlling a pressure control valve 6 on the basis of the pressure detected by the pressure sensor 5 from the time point when the pressure of the inspection space reaches the approximate target value. <P>COPYRIGHT: (C)2010,JPO&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. However, in such a direct pressure type leak detection method, since 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), accurate leak detection is possible. It can be difficult.

In recent years, therefore, a leak detection method called a so-called differential pressure type has been proposed (see, for example, Patent Document 1). 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-A-3-77041

  By the way, in the above-described differential pressure type leak detection method, in order to set the pressure in the examination space including the sealed tank in which the sealed container to be measured is arranged to a predetermined target value, the examination fluid is caused to flow into the examination space. It is necessary to increase the pressure in the inspection space (or to reduce the pressure in the inspection space by causing the inspection fluid to flow out of the inspection space). When performing such pressure setting, conventionally, the pressure in the examination space is gradually increased (decreased) by detecting the pressure in the examination space and controlling the opening of the pressure control valve based on the detected pressure. ) To reach the target value. However, when such a conventional pressure setting method is adopted, since it takes a considerable time to set the pressure, there is a problem in that the sealed container to be measured that is subject to leak detection is exposed to high pressure (low pressure) for a long time. .

  The present invention has been made in view of such circumstances, and provides a leak detection system (method) that can significantly reduce the time during which a sealed container to be measured is exposed to high pressure or low pressure. With the goal.

  In order to achieve the above object, a first leak detection system according to the present invention includes an inside of a first sealed container to be measured that is configured to have an opening and be sealed by a lid on the opening. The inspection fluid is caused to flow in or out of the first inspection space including the inside of the leak inspection pipe whose end is connected to the opening of the first sealed container to be measured. A system for detecting a leak of a first sealed container to be measured by setting a pressure in the space to a predetermined target value different from the atmospheric pressure, the flow of the inspection fluid flowing into or out of the first inspection space A mass flow controller that adjusts the flow rate and a mass flow controller that controls the flow of the test fluid at a predetermined flow rate to flow into or out of the first test space, thereby setting the pressure in the first test space to a predetermined value close to the target value. Approximate target value of The flow rate control means to reach, the pressure detection means for detecting the pressure in the first examination space, the pressure control valve for controlling the pressure in the first examination space, and the pressure in the first examination space reach the approximate target value Pressure control means for controlling the pressure control valve based on the pressure detected by the pressure detection means from the point of time, thereby causing the pressure in the first examination space to reach the target value.

  Further, a first leak detection method according to the present invention includes an inside of a first measured sealed container configured to have an opening and to be sealed by a lid applied to the opening, and the first covered object. The pressure of the first inspection space is increased by flowing the inspection fluid into or out of the first inspection space including the inside of the leak inspection pipe whose end is connected to the opening of the measurement sealed container. A mass flow method for detecting a leak in the first sealed container to be measured by setting a predetermined target value different from the atmospheric pressure, and adjusting a flow rate of the inspection fluid flowing into or out of the first inspection space A controller, a pressure detection means for detecting the pressure in the first inspection space, and a pressure control valve for controlling the pressure in the first inspection space are employed, and a predetermined flow rate of the inspection fluid is supplied to the first inspection space. Mass flow controller to flow in or out By controlling the flow rate, the flow rate control step for causing the pressure in the first examination space to reach a predetermined approximate target value close to the target value, and the pressure detection from the point in time when the pressure in the first examination space reaches the approximate target value. A pressure control step of controlling the pressure control valve based on the pressure detected by the means to cause the pressure in the first examination space to reach the target value.

  When such a configuration and method are employed, when the pressure of the first examination space including the inside of the first measured closed container (for example, a container such as a PET bottle) sealed by the lid is set to a predetermined target value. First, using a mass flow controller, a test fluid having a predetermined flow rate is caused to flow into (outflow) the first test space so that the pressure in the first test space quickly reaches a target value close to the target value. Thereafter, the pressure in the first examination space can be controlled using the pressure control valve to finally reach the target value. Therefore, compared with the case where the pressure in the first examination space is set to the target value by using the pressure control valve from the beginning, the time required for the pressure setting can be greatly shortened. As a result, it is possible to prevent the container subject to leak detection from being exposed to high pressure (low pressure) for a long time, and thus damage and breakage of the container can be prevented.

  Further, the second leak detection system according to the present invention includes a leak test chamber having a second sealed container to be measured, which is sealed in advance, and having an opening, and an opening of the leak test chamber. A leak inspection pipe whose end is connected to the second inspection space, and a flow of the inspection fluid into or out of the second inspection space including the inside of the leak inspection chamber and the inside of the leak inspection pipe, A system for detecting a leak in the second sealed container to be measured by setting the pressure in the second examination space to a predetermined target value different from the atmospheric pressure, and flowing into or out of the second examination space. By controlling the mass flow controller for adjusting the flow rate of the inspection fluid, and controlling the mass flow controller so that the predetermined flow rate of the inspection fluid flows into or out of the second inspection space, Flow rate control means for causing the pressure in the examination space to reach a predetermined approximate target value close to the target value, pressure detection means for detecting the pressure in the second examination space, and a pressure control valve for controlling the pressure in the second examination space And the pressure in the second examination space reaches the target value by controlling the pressure control valve based on the pressure detected by the pressure detection means from the time when the pressure in the second examination space reaches the approximate target value. Pressure control means.

  The second leak detection method according to the present invention includes a leak test chamber having a second sealed container to be measured, which is sealed in advance, and having an opening, and an opening of the leak test chamber. A leak inspection pipe whose end is connected to the first inspection space, and flowing the inspection fluid into or out of the second inspection space including the inside of the leak inspection chamber and the inside of the leak inspection pipe. A method of detecting a leak in the second sealed container to be measured by setting the pressure in the second inspection space to a predetermined target value different from the atmospheric pressure, and flowing in or out of the second inspection space A mass flow controller that adjusts the flow rate of the inspection fluid, a pressure detection means that detects the pressure of the second inspection space, and a pressure control valve that controls the pressure of the second inspection space, Inspection fluid A flow rate control step for controlling the mass flow controller so as to flow in or out of the second inspection space, thereby causing the pressure in the second inspection space to reach a predetermined approximate target value close to the target value; and a second inspection A pressure control step for controlling the pressure control valve based on the pressure detected by the pressure detection means from the time when the pressure in the space reaches the approximate target value, thereby causing the pressure in the second inspection space to reach the target value; Is included.

  When such a configuration and method are employed, the pressure in the second inspection space including the inside of the leak inspection chamber in which the second sealed container to be measured (for example, a container such as a canned can) is previously sealed is set to a predetermined value. When setting the target value, first, a mass flow controller is used to flow (extract) a test fluid at a predetermined flow rate into the second test space, and the pressure in the second test space is close to the target value. The target value can be reached quickly, and then the pressure in the second examination space can be controlled using the pressure control valve to finally reach the target value. Therefore, compared with the case where the pressure in the second inspection space is set to the target value using the pressure control valve from the beginning, the time required for the pressure setting can be greatly shortened. As a result, it is possible to prevent the container subject to leak detection from being exposed to high pressure (low pressure) for a long time, and thus damage and breakage of the container can be prevented.

  In the leak detection system, a pressure control valve may be provided in the leak inspection pipe, and a mass flow controller may be provided in a bypass pipe connected to the leak inspection pipe so as to bypass the pressure control valve.

  In the leak detection system, it is preferable that a buffer tank is provided at a position downstream of the pressure control valve of the leak inspection pipe.

  When such a configuration is adopted, since a buffer tank is provided on the downstream side of the pressure control valve, hunting occurs during pressure control by the pressure control valve (for example, feedback control based on the pressure detected by the pressure detection means). Can be suppressed.

  The leak detection system may further include a branch pipe that branches from a position downstream of the pressure control valve of the leak inspection pipe, and a second mass flow controller provided in the branch pipe.

  When such a configuration is adopted, the mass flow controller having a fast response speed is provided on the downstream side of the pressure control valve, so that the pressure control by the pressure control valve can be performed quickly and with high accuracy. Even when the inspection fluid flows excessively (outflows) into the inspection space, the mass flow controller can prevent the pressure in the inspection space from changing excessively.

  In addition, a third leak detection system according to the present invention includes an inside of a first container to be measured which is configured to have an opening and to be sealed by a lid on the opening, and the first object to be measured. The pressure of the first inspection space is increased by flowing the inspection fluid into or out of the first inspection space including the inside of the leak inspection pipe whose end is connected to the opening of the measurement sealed container. A mass flow that sets a predetermined target value different from the atmospheric pressure to detect a leak of the first sealed container to be measured and adjusts the flow rate of the inspection fluid flowing into or out of the first inspection space And a flow rate control means for controlling the mass flow controller so as to cause the inspection fluid having a predetermined flow rate to flow into or out of the first inspection space, thereby causing the pressure in the first inspection space to reach the target value. With Than is.

  Further, a third leak detection method according to the present invention includes an inside of a first measured sealed container that has an opening and is sealed with a lid on the opening, and a first object to be measured. The pressure of the first inspection space is increased by flowing the inspection fluid into or out of the first inspection space including the inside of the leak inspection pipe whose end is connected to the opening of the measurement sealed container. A mass flow method for detecting a leak in the first sealed container to be measured by setting a predetermined target value different from the atmospheric pressure, and adjusting a flow rate of the inspection fluid flowing into or out of the first inspection space A flow rate control that employs a controller to control the mass flow controller so that a predetermined flow rate of the inspection fluid flows into or out of the first inspection space, thereby causing the pressure in the first inspection space to reach the target value. Including processes .

  When such a configuration and method are employed, when the pressure of the first examination space including the inside of the first measured closed container (for example, a container such as a PET bottle) sealed by the lid is set to a predetermined target value. By using the mass flow controller, the inspection fluid having a predetermined flow rate can be caused to flow into (outflow) the first inspection space, so that the pressure in the first inspection space can quickly reach the target value. Therefore, compared with the case where the pressure in the first examination space is set to the target value by using the pressure control valve from the beginning, the time required for the pressure setting can be greatly shortened. As a result, it is possible to prevent the container subject to leak detection from being exposed to high pressure (low pressure) for a long time, and thus damage and breakage of the container can be prevented. Further, when such a configuration and method are employed, the pressure setting of the first inspection space can be realized without using a pressure control valve or a pressure sensor. Therefore, even when a response delay or failure of the pressure control valve or the pressure sensor occurs, it is possible to protect the container that is a leak detection target.

  Further, a fourth leak detection system according to the present invention includes a leak inspection chamber having a second sealed container to be measured, which is sealed in advance, and having an opening, and an opening of the leak inspection chamber. A leak inspection pipe whose end is connected to the second inspection space, and a flow of the inspection fluid into or out of the second inspection space including the inside of the leak inspection chamber and the inside of the leak inspection pipe, A system for detecting a leak in the second sealed container to be measured by setting the pressure in the second examination space to a predetermined target value different from the atmospheric pressure, and flowing into or out of the second examination space. By controlling the mass flow controller for adjusting the flow rate of the inspection fluid, and controlling the mass flow controller so that the predetermined flow rate of the inspection fluid flows into or out of the second inspection space, And flow control means to reach the pressure of the examination space to the target value, but with a.

  A fourth leak detection method according to the present invention includes a leak test chamber having a second sealed container to be measured, which is sealed in advance, and having an opening, and an opening of the leak test chamber. A leak inspection pipe whose end is connected to the first inspection space, and flowing the inspection fluid into or out of the second inspection space including the inside of the leak inspection chamber and the inside of the leak inspection pipe. A method of detecting a leak in the second sealed container to be measured by setting the pressure in the second inspection space to a predetermined target value different from the atmospheric pressure, and flowing in or out of the second inspection space By adopting a mass flow controller that adjusts the flow rate of the inspection fluid to be performed, and controlling the mass flow controller so that the predetermined amount of inspection fluid flows into or out of the second inspection space, It is intended to include a flow control process to reach the pressure of the examination space to the target value.

  When such a configuration and method are employed, the pressure in the second inspection space including the inside of the leak inspection chamber in which the second sealed container to be measured (for example, a container such as a canned can) is previously sealed is set to a predetermined value. When the target value is set, the mass flow controller may be used to cause a predetermined flow rate of the inspection fluid to flow into (outflow) the second inspection space so that the pressure in the second inspection space quickly reaches the target value. it can. Therefore, compared with the case where the pressure in the second inspection space is set to the target value using the pressure control valve from the beginning, the time required for the pressure setting can be greatly shortened. As a result, it is possible to prevent the container subject to leak detection from being exposed to high pressure (low pressure) for a long time, and thus damage and breakage of the container can be prevented. Further, when such a configuration and method are employed, the pressure setting in the second inspection space can be realized without using a pressure control valve or a pressure sensor. Therefore, even when a response delay or failure of the pressure control valve or the pressure sensor occurs, it is possible to protect the container that is a leak detection target.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the leak detection system (method) which can reduce significantly the time which the to-be-measured sealed container used as leak detection object is exposed to a high pressure or a low pressure.

  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 is provided on the substrate 41 provided with the cavity 42, the insulating film 43 disposed on the substrate 41 so as to cover the cavity 42, and the insulating film 43. The heater 44 has a first resistance temperature detector 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 resistance temperature detector 45 is used to detect the temperature on one side of the heater 44, and the second resistance temperature detector 46 is used to detect 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 examination space are calculated from the difference between the electrical resistance of the first resistance temperature detector 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. That is, the pressure sensor 5 functions as pressure detection means in the present invention. 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.

  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, and by storing a large volume of air therein, the pressure in the inspection space after setting a predetermined pressure (target value) is increased. It fulfills a function (buffer function) that suppresses a sudden drop caused by a leak and contributes to an improvement in the accuracy of the leak test. The buffer tank 9 also functions to suppress hunting during pressure control by the pressure control valve 6 (feedback control based on the pressure detected by the pressure sensor 5). 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 2. 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. The supercharging countermeasure mass flow controller 10 corresponds to the second mass flow controller of the present invention.

  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 reference flow rate characteristic described later) used for determining the leak of the first sealed container 100. The display unit 23 outputs the determination result of leak (presence / absence of leak) as image information.

  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 to set the pressure in the first examination space to a 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 air to flow into the first inspection space, whereby the pressure detected by the pressure sensor 5 is close to the target value. A predetermined approximate target value is reached. The flow rate that flows in at this time corresponds to the integrated flow rate of air for reaching the approximate target value. The approximate target value can be set to 90% of the target value, for example.

  Thereafter, 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. That is, the central control unit 21 functions as a flow rate control unit and a pressure control unit in the present invention. The central control unit 21 closes the cutoff valve 3 immediately after the pressure detected by the pressure sensor 5 reaches the target value.

  Further, the central control unit 21 performs the first sealing based on the flow rate characteristic of the flow rate detected by the flow meter 4 and the reference flow rate characteristic when a leak-free reference sealed container is connected instead of the first container 100. The presence or absence of a leak in the container 100 is determined. In the present embodiment, as a flow rate characteristic, a time flow rate curve (representing a time history of the flow rate of air flowing in the first examination space in the process in which the pressure in the first examination space recovers from a predetermined value to atmospheric pressure). Curve). It has been experimentally shown that such a time flow rate curve does not depend on the temperature of the sealed container to be leaked (that is, has a constant shape regardless of the temperature of the sealed container to be measured). Therefore, when such a time flow curve is employed to make a leak determination, the leak determination time can be shortened.

  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 based on the operation of the operation unit 24 by the user, etc., thereby conducting a first flow of air at a predetermined flow rate. The pressure detected by the pressure sensor 5 is made to flow into the space to reach a predetermined approximate target value close to the target value (flow rate control step: S2). Next, 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 air to further flow into the first examination space. The detected pressure at 5 reaches the target value (pressure control step: S3), and the shutoff valve 3 is closed. By these flow rate control step S2 and pressure control step S3, the pressure in the first inspection space is set to a predetermined target value.

  Subsequently, the central control unit 21 of the determination device 20 of the leak detection system 1 determines the flow rate characteristic of air in the first examination space detected by the flow meter 4 (time flow rate curve corresponding to the first sealed container 100), leak, and the like. Whether or not there is a leak in the first hermetic container 100 is determined based on the reference flow rate characteristics when a reference hermetic container without a gap is connected instead of the first hermetic container 100 (leak determination step: S4). Thereafter, the central control unit 21 of the determiner 20 displays the presence / absence of the leak determined in the leak determination step S4 on the display unit 23 based on the operation of the operation unit 24 by the user or the like (determination result display step: S5). ), The whole process is completed.

  In the leak detection system 1 according to the embodiment described above, the pressure in the first examination space including the inside of the first sealed container 100 (for example, a container such as a PET bottle) sealed by the lid is set to a predetermined target value. At the time of setting, first, the mass flow controller 8 for initial supply is used to cause a predetermined flow rate of air to flow into the first examination space so that the pressure in the first examination space quickly reaches a recent target value close to the target value. Thereafter, the pressure in the first examination space can be controlled using the pressure control valve 6 to finally reach the target value. Therefore, compared with the case where the pressure in the first examination space is set to the target value by using the pressure control valve 6 from the beginning, the time required for setting the pressure can be greatly shortened. As a result, it is possible to prevent the first sealed container 100 that is the target of leak detection from being exposed to high pressure for a long time, and thus it is possible to prevent damage and breakage of the first sealed container 100.

  Further, in the leak detection system 1 according to the above-described embodiment, the buffer tank 9 is provided at a position downstream of the pressure control valve 6 of the leak inspection pipe 2. The occurrence of hunting during feedback control based on the pressure detected by the sensor 5 can be suppressed.

  Further, in the leak detection system 1 according to the embodiment described above, the supercharging countermeasure mass flow controller 10 having a quick response speed is provided at the downstream side of the pressure control valve 6 of the leak inspection pipe 2. The pressure control by the control valve 6 can be performed quickly and with high accuracy. Further, even when air excessively flows into the first inspection space, the supercharging countermeasure mass flow controller 10 can prevent the pressure in the first inspection space from changing excessively. Become.

[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. 5, the leak detection system 1 </ b> A according to the present embodiment includes a leak test pipe 2, a leak test chamber 12 connected to the end 2 a of the leak test 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 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. 5, 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. The flow rate that flows in at this time corresponds to the integrated flow rate of air for reaching the approximate target value. The approximate target value can be set to 90% of the target value, for example.

  Thereafter, 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. That is, the central control unit 21A functions as a flow rate control unit and a pressure control unit in the present invention. The central control unit 21A closes the shutoff valve 3 immediately after the pressure detected by the pressure sensor 5 reaches the target value.

  Further, the central control unit 21A performs the second operation based on the flow rate characteristic of the flow rate detected by the flow meter 4 and the reference flow rate characteristic when a leak-free reference sealed container is connected instead of the second sealed container 200. The presence or absence of a leak in the sealed container 200 is determined. In the present embodiment, as a flow rate characteristic, a time flow rate curve (a curve representing a time history of the flow rate of air flowing through the second examination space in the process in which the pressure in the second examination space is restored from the predetermined value to the atmospheric pressure). ) Is adopted.

  Next, a leak detection method according to the present embodiment (a method of detecting a leak in the second sealed container 200 using the leak detection system 1A) will be described using 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 controls the initial supply mass flow controller 8 based on the operation of the operation unit 24A by the user, etc., so that a predetermined flow rate of air is subjected to the second inspection. The pressure detected by the pressure sensor 5 is made to flow into the space to reach a predetermined approximate target value close to the target value (flow rate control step: S12). Next, 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 further supplying the inspection fluid to the leak inspection pipe 2 (and the leak inspection pipe). The pressure is detected by the pressure sensor 5 to reach the target value (pressure control step: S13), and the shutoff valve 3 is closed. By these flow rate control step S12 and pressure control step S13, the pressure in the second inspection space is set to a predetermined target value.

  Subsequently, the central control unit 21A of the determination device 20A of the leak detection system 1A has a flow characteristic of air in the second inspection space detected by the flow meter 4 (time flow curve corresponding to the second sealed container 200), and Whether or not there is a leak in the second sealed container 200 is determined based on a reference flow rate characteristic when a reference sealed container without a leak is connected instead of the second sealed container 200 (leak determination step: S14). Thereafter, the central controller 21A of the determiner 20A displays the presence / absence of the leak determined in the leak determination step S14 on the display unit 23A based on the operation of the operation unit 24A by the user (determination result display step: S15). ), The whole process is completed.

  In the leak detection system 1A according to the embodiment described above, the second inspection space including the inside of the leak inspection chamber 12 in which the second sealed container 200 (for example, a container such as a canned can) that is sealed in advance is arranged. When the initial pressure is set to a predetermined target value, first, the initial flow mass flow controller 8 is used to flow a predetermined flow rate of air into the second inspection space to bring the pressure in the second inspection space close to the target value. The target value can be reached quickly, and then the pressure in the second examination space can be controlled using the pressure control valve 6 to finally reach the target value. Therefore, compared with the case where the pressure in the second inspection space is set to the target value by using the pressure control valve 6 from the beginning, the time required for the pressure setting can be greatly shortened. As a result, it is possible to prevent the leak-detected second sealed container 200 from being exposed to a high pressure for a long time, and thus it is possible to prevent damage and breakage of the container.

  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. Then, when restarting the leak inspection after replacing the object to be measured, by opening the second shut-off valve and supplying the inspection fluid again, and simultaneously controlling the pressure in the inspection space using the pressure control valve 6, 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. When resuming the leak inspection, the second shutoff valve is opened, and at the same time, the initial supply mass flow controller 8 is used to supply a predetermined flow rate of air (a flow rate different from the case where the second shutoff valve is not used) into the examination space. It is also possible to cause the pressure in the examination space to reach the target value recently, and then to control the pressure in the examination space using the pressure control valve 6 so that the pressure in the examination space reaches the target value.

  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”) in place of the pressure control valve 6 is provided in the leak inspection pipe 2, and an inspection fluid is prepared by using the third mass flow controller and the initial supply mass flow controller 8. May be stopped.

  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.

  Moreover, in each above embodiment, although the example which used the flow meter 4 only at the time of leak determination was shown, the flow meter 4 can be used also at the time of a pressure setting. That is, when air is introduced into the examination space using the initial supply mass flow controller 8, the flow rate of the air flowing through the examination space is detected by the flow meter 4, and the integrated flow rate from the inflow start point is calculated. The mass flow controller 8 for initial supply can be stopped when the flow rate reaches a predetermined value (a value at which the pressure in the examination space becomes an approximate target value).

  In each of the above embodiments, when the pressure in the examination space is set to a predetermined target value, flow control using the mass flow controller 8, pressure control using the pressure sensor 5 and the pressure control valve 6, Although the example which demonstrated the system (method) which employ | adopted both of this was shown, you may set the pressure of test | inspection space to a predetermined target value using only the mass flow controller 8. FIG. In such a case, a predetermined flow rate (target flow rate) necessary to reach the predetermined target value in the inspection space is calculated in advance, and the mass flow controller 8 is controlled after connection (arrangement) of the measurement target object. Thus, the inspection fluid having the target flow rate is caused to flow into the inspection space so that the pressure in the inspection space reaches a predetermined target value, and then the leak inspection is performed based on the flow rate characteristics and the like. When such a system (method) is employed, the pressure setting of the inspection space can be realized without using the pressure sensor 5 or the pressure control valve 6. Therefore, even when a response delay or failure of the pressure sensor 5 or the pressure control valve 6 occurs, it is possible to protect the container that is a leak detection target.

  In each of the above embodiments, an example in which a thermal flow meter including a thermal flow sensor having a semiconductor diaphragm is employed as a flow meter has been described. However, instead of such a thermal flow sensor, another method (super You may employ | adopt the flowmeter provided with the flow rate sensor of a sonic type and an electromagnetic type. 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 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 ... Leak inspection pipe 2a ... Terminal 4 ... Flow meter 5 ... Pressure sensor (pressure detection means)
6 ... Pressure control valve 7 ... Bypass piping 8 ... Mass flow controller for initial supply 9 ... Buffer tank 10 ... Mass flow controller for supercharging countermeasure (second mass flow controller)
DESCRIPTION OF SYMBOLS 11 ... Branch piping 12 ... Leak inspection chamber 13 ... Opening part 21 * 21A ... Central control part (flow rate control means, pressure control means)
100: 1st airtight container (1st airtight container to be measured)
110: opening 200 ... second sealed container (second measured sealed container)

Claims (11)

An end is connected to the inside of the first measured sealed container configured to have an opening and to be sealed by applying a lid to the opening, and to the opening of the first measured sealed container By causing the inspection fluid to flow into or out of the first inspection space including the inside of the leak inspection pipe, the pressure of the first inspection space is set to a predetermined target value different from the atmospheric pressure. A system for detecting a leak in the first container to be measured,
A mass flow controller for adjusting the flow rate of the inspection fluid flowing into or out of the first inspection space;
By controlling the mass flow controller so that a predetermined flow rate of the inspection fluid flows into or out of the first inspection space, the pressure in the first inspection space is set to a predetermined approximate target value close to the target value. Flow rate control means to reach,
Pressure detecting means for detecting the pressure in the first examination space;
A pressure control valve for controlling the pressure in the first examination space;
The pressure in the first examination space is controlled by controlling the pressure control valve based on the pressure detected by the pressure detection means from the time when the pressure in the first examination space reaches the approximate target value. Pressure control means for reaching a target value,
A leak detection system for sealed containers. A leak test chamber having an opening and a second sealed container to be measured, which is sealed in advance, and a leak test pipe whose end is connected to the opening of the leak test chamber; A pressure of the second inspection space is increased by flowing an inspection fluid into or out of the second inspection space including the inside of the leak inspection chamber and the inside of the leak inspection pipe. A system for detecting a leak of the second measured sealed container by setting a predetermined target value different from the atmospheric pressure,
A mass flow controller for adjusting the flow rate of the inspection fluid flowing into or out of the second inspection space;
By controlling the mass flow controller so that a predetermined flow rate of inspection fluid flows into or out of the second inspection space, the pressure in the second inspection space is set to a predetermined approximate target value close to the target value. Flow rate control means to reach,
Pressure detecting means for detecting the pressure in the second examination space;
A pressure control valve for controlling the pressure in the second examination space;
The pressure in the second examination space is controlled by controlling the pressure control valve based on the pressure detected by the pressure detection means from the time when the pressure in the second examination space reaches the approximate target value. Pressure control means for reaching a target value,
A leak detection system for sealed containers. The pressure control valve is provided in the leak inspection pipe,
The mass flow controller is provided in a bypass pipe connected to the leak inspection pipe so as to bypass the pressure control valve.
The leak detection system of the airtight container of Claim 1 or 2. A buffer tank provided at a position downstream of the pressure control valve of the leak inspection pipe;
The leak detection system for an airtight container according to claim 3. A branch pipe branched from a position downstream of the pressure control valve of the leak inspection pipe;
A second mass flow controller provided in the branch pipe,
The leak detection system of the airtight container of Claim 3 or 4. An end is connected to the inside of the first measured sealed container configured to have an opening and to be sealed by applying a lid to the opening, and to the opening of the first measured sealed container By causing the inspection fluid to flow into or out of the first inspection space including the inside of the leak inspection pipe, the pressure of the first inspection space is set to a predetermined target value different from the atmospheric pressure. A system for detecting a leak in the first container to be measured,
A mass flow controller for adjusting the flow rate of the inspection fluid flowing into or out of the first inspection space;
Flow rate control means for controlling the mass flow controller so that a predetermined flow rate of the inspection fluid flows into or out of the first inspection space, thereby causing the pressure in the first inspection space to reach the target value; Comprising
A leak detection system for sealed containers. A leak test chamber having an opening and a second sealed container to be measured, which is sealed in advance, and a leak test pipe whose end is connected to the opening of the leak test chamber; A pressure of the second inspection space is increased by flowing an inspection fluid into or out of the second inspection space including the inside of the leak inspection chamber and the inside of the leak inspection pipe. A system for detecting a leak of the second measured sealed container by setting a predetermined target value different from the atmospheric pressure,
A mass flow controller for adjusting the flow rate of the inspection fluid flowing into or out of the second inspection space;
Flow rate control means for controlling the mass flow controller so that a predetermined flow rate of the inspection fluid flows into or out of the second inspection space, thereby causing the pressure in the second inspection space to reach the target value; Comprising
A leak detection system for sealed containers. An end is connected to the inside of the first measured sealed container configured to have an opening and to be sealed by applying a lid to the opening, and to the opening of the first measured sealed container By causing the inspection fluid to flow into or out of the first inspection space including the inside of the leak inspection pipe, the pressure of the first inspection space is set to a predetermined target value different from the atmospheric pressure. A method for detecting a leak in the first measured sealed container,
A mass flow controller for adjusting a flow rate of the inspection fluid flowing into or out of the first inspection space; pressure detection means for detecting a pressure in the first inspection space; and a pressure in the first inspection space. Adopting pressure control valve to control,
By controlling the mass flow controller so that a predetermined flow rate of the inspection fluid flows into or out of the first inspection space, the pressure in the first inspection space is set to a predetermined approximate target value close to the target value. A flow control process to reach
The pressure in the first examination space is controlled by controlling the pressure control valve based on the pressure detected by the pressure detection means from the time when the pressure in the first examination space reaches the approximate target value. A pressure control step for reaching a target value,
A method for detecting leaks in sealed containers. An end is connected to the inside of the first measured sealed container configured to have an opening and to be sealed by applying a lid to the opening, and to the opening of the first measured sealed container By causing the inspection fluid to flow into or out of the first inspection space including the inside of the leak inspection pipe, the pressure of the first inspection space is set to a predetermined target value different from the atmospheric pressure. A method for detecting a leak in the first measured sealed container,
A mass flow controller that adjusts the flow rate of the inspection fluid that flows into or out of the first inspection space is employed, and the inspection fluid having a predetermined flow rate is allowed to flow into or out of the first inspection space. Including a flow rate control step of controlling the mass flow controller to cause the pressure in the first examination space to reach the target value,
A method for detecting leaks in sealed containers. A leak test chamber having an opening and a second sealed container to be measured, which is sealed in advance, and a leak test pipe whose end is connected to the opening of the leak test chamber; The pressure of the second inspection space is reduced by flowing the inspection fluid into or out of the second inspection space including the inside of the leak inspection chamber and the inside of the leak inspection pipe. A method of detecting a leak in the second measured sealed container by setting to a predetermined target value different from atmospheric pressure,
A mass flow controller for adjusting the flow rate of the inspection fluid flowing into or out of the second inspection space; pressure detecting means for detecting the pressure of the second inspection space; and the pressure of the second inspection space. Adopting pressure control valve to control,
By controlling the mass flow controller so that a predetermined flow rate of the inspection fluid flows into or out of the second inspection space, the pressure in the second inspection space is set to a predetermined approximate target value close to the target value. A flow control process to reach
The pressure in the second examination space is controlled by controlling the pressure control valve based on the pressure detected by the pressure detection means from the time when the pressure in the second examination space reaches the approximate target value. A pressure control step for reaching a target value,
A method for detecting leaks in sealed containers. A leak test chamber having an opening and a second sealed container to be measured, which is sealed in advance, and a leak test pipe whose end is connected to the opening of the leak test chamber; The pressure of the second inspection space is reduced by flowing the inspection fluid into or out of the second inspection space including the inside of the leak inspection chamber and the inside of the leak inspection pipe. A method of detecting a leak in the second measured sealed container by setting to a predetermined target value different from atmospheric pressure,
A mass flow controller that adjusts the flow rate of the inspection fluid flowing into or out of the second inspection space is employed, and the inspection fluid having a predetermined flow rate is allowed to flow into or out of the second inspection space. Including a flow rate control step of controlling the mass flow controller to cause the pressure in the second examination space to reach the target value,
A method for detecting leaks in sealed containers.

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