JP4816931B2 - Container airtightness inspection method and container airtightness inspection system used in the method - Google Patents

Description

  The present invention relates to an airtightness inspection method for containers filled with contents such as volatile liquids and gases, and an airtightness inspection system for containers used in the method.

  Conventionally, a method for detecting gas leakage in a cylinder filled with a gas such as LPG has been proposed (see Patent Document 1). In this gas leakage inspection method, a cylinder valve is covered with a cap, and the gas in the cap is sucked and led to a gas detector. Thereby, the gas leaking from the valve can be detected by the gas detector, and the suitability of the airtightness of the cylinder can be determined based on the detection result.

In addition, a method for inspecting the hermeticity of a sealed package containing food, medicine, cosmetics and the like has been proposed (see Patent Document 2). In this method, a container filled with a breathable elastic body (for example, urethane resin) is sealed in a sealed package body in which an inert gas (for example, helium gas) is sealed together with an object to be packaged such as food, medicine, and cosmetics. In addition, the elastic body presses the hermetic package in the container, and the gas in the container is guided to the gas analysis unit. Thereby, the inert gas which leaks from the sealed packaging body compressed by the elastic body can be detected by the gas analysis unit, and the suitability of the hermeticity of the sealed packaging body can be determined based on the detection result.
Japanese Patent Laid-Open No. 10-332098 JP 2004-257717 A

  However, in the inspection method as described above, a cap or another container is put on each inspection object container (cylinder, sealed package), and a predetermined gas is included in the gas sucked from the cap or another container. In order to find a hermetic defect due to a very small defect such as a pinhole, it is determined whether or not the individual container to be inspected is appropriate. The gas suction operation must be performed for a relatively long time, and it is difficult to perform an efficient inspection.

  The present invention has been made to solve such a conventional problem, and it is possible to detect a hermetic failure due to an extremely small defect such as a pinhole while preventing a decrease in inspection efficiency as much as possible. An airtightness inspection method and an airtightness inspection system for a container used in the method are provided.

In the container airtightness inspection method according to the present invention, a plurality of containers containing contents are stored in a case, and the container is fixed by covering the open upper surface of the case with an upper lid having a shutter plate covering a through hole. And gas in the case containing a plurality of containers is sucked with a nozzle that spreads the shutter plate and enters the case, and detects the gas resulting from the contents of the container from the sucked gas It has a configuration including a gas detection step and a determination step of determining appropriateness of airtightness of the plurality of containers accommodated in the case based on a detection result in the gas detection step.

  With such a configuration, if gas due to the contents leaks from at least one of the plurality of containers accommodated in the case, the gas stays in the case without immediately diffusing, and from the case Since the gas to be sucked contains the gas, it is possible to determine the suitability of the airtightness of a plurality of containers accommodated in the case based on the detection result of the gas. .

  Further, the container airtightness inspection method according to the present invention may include a storage step of temporarily storing the case in which the plurality of containers are accommodated before the gas detection step.

  With such a configuration, even if the flow rate of gas leaking from a very small defect such as a pinhole in any of a plurality of containers accommodated in the case is small, the case is stored in the case while the case is being stored. Therefore, more leaked gas is accumulated, so that it is possible to more accurately determine the poor airtightness of the container based on the gas detection result in the gas detection process.

  Further, in the container airtightness inspection method according to the present invention, before the gas detection step, each container is set such that the temperature of the contents of each of the plurality of containers accommodated in the case is higher than the temperature at the time of filling. It can be set as the structure which has a heating process which heats.

  With such a configuration, before the gas detection step, the temperature of the contents of each of the plurality of containers accommodated in the case becomes higher than the temperature at the time of filling. Expansion and vaporization of the contents of the container are promoted. For this reason, when there is a defect in the container, gas leakage from the defect is promoted, and even if the defect is a very small defect such as a pinhole, the container It becomes possible to determine the airtightness more accurately.

  As long as the temperature of the contents of each of the plurality of containers in the case is higher than the temperature at the time of filling, the execution timing of the heating step is not particularly limited. The heating process may be performed before the container housing process, that is, the container may be housed in the case after being heated, or may be performed after the container housing process. That is, you may make it heat the some container accommodated in the case, for example with the case.

  Further, the container airtightness inspection method according to the present invention may include a step of moving the case so that its posture changes between the container housing step and the gas detection step.

  With such a configuration, since the posture of the case containing a plurality of containers is changed before reaching the gas detection step, defects formed in the containers in the case are at least temporarily before reaching the gas detection step. It is possible to increase the possibility that the gas is likely to leak. For this reason, even if the defect formed in the container is an extremely small defect such as a pinhole, it is possible to more accurately determine the poor airtightness of the container based on the gas detection result in the gas detection process. Become.

  In the container airtightness inspection method according to the present invention, the step of moving the case may include a case reversing step of turning the case upside down.

  With such a configuration, since the case containing a plurality of containers is turned upside down before reaching the gas detection step, defects formed in the containers in the case are at least temporarily before reaching the gas inspection step. Can increase the possibility of gas leaking. For this reason, even if the defect formed in the container is an extremely small defect such as a pinhole, it is possible to more accurately determine the poor airtightness of the container based on the gas detection result in the gas inspection process. Become.

  Furthermore, in the airtightness inspection method for a container according to the present invention, the case reversing step can be configured to invert the case up and down several times.

  With such a configuration, the gas inspection process can be performed on the case in which the plurality of containers are in the original direction (direction in the container housing process).

A container airtightness inspection system according to the present invention includes a transport mechanism for transporting a case containing a plurality of containers containing contents, and a case detection means for detecting that the case is at a preset inspection position. A nozzle drive mechanism that drives the nozzle between a set position and a retracted position at the inspection position; and a suction mechanism that is installed at the inspection position and sucks the gas in the case through the nozzle inserted into the case; Gas detection means for outputting a detection signal corresponding to the amount of gas caused by the contents of the container contained in the gas sucked by the suction mechanism;
A determination unit that determines suitability of airtightness of the plurality of containers accommodated in the case based on a detection signal output from the gas detection unit; and the case detection unit includes the case at the detection position. A transport stop control means for stopping transport of the case by the transport mechanism when detected, and after the case stops at the inspection position, the nozzle drive mechanism moves the nozzle from the retracted position to the set position. Nozzle drive control means for driving the nozzle and inserting the nozzle into the case, and operation control means for effectively operating the suction mechanism in a state where the nozzle is inserted into the case. Can do.

  With such a configuration, when it is detected that the case containing the plurality of containers is in the inspection position in the process of being conveyed by the conveyance mechanism, the conveyance of the case is stopped and the nozzle is moved to the set position. And inserted into the case. In this state, the gas detection unit and the determination unit perform the above-described gas detection process and determination process.

  According to the container airtightness inspection method and the airtightness inspection system used in the method according to the present invention, in order to detect gas due to the contents of the container leaking from extremely small defects such as pinholes, On the other hand, even if a relatively long inspection time is required, it is possible to judge the suitability of the airtightness of a plurality of containers in a case as a whole. It becomes possible to find an airtight defect due to an extremely small defect.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In the container airtightness inspection method according to an embodiment of the present invention, a bottle container filled with methanol (volatile liquid fuel) serving as a fuel for a fuel cell is an inspection object.

  First, as shown in FIG. 1, a predetermined number (plural) of bottle containers 10 that have undergone a fuel (methanol) filling process are stored in the case 100 (container storing process). The case 100 is formed of, for example, a synthetic resin, and the upper surface is open. The upper lid 100a is put on the opened upper surface and fixed. For example, a through hole 101 as shown in FIG. 2 (a) is formed in a substantially central portion of the upper lid 100a, and two flexible shutter plates 110a and 110b are provided on the back surface of the upper lid 100a. It is attached so as to cover the through hole 101. These shutter plates 110a and 110b are constituted by rubber plates having appropriate elasticity. As will be described later, when the nozzle 33 for sucking the gas in the case 100 is inserted into the through hole 101 from the front side of the upper lid 100a, the nozzle 33 has two shutter plates 110a and 110b as shown in FIG. Is spread and enters the case 100.

  As described above, the case 100 in which the plurality of bottle containers 10 filled with fuel are accommodated is temporarily stored, for example, in units of several to several tens in a predetermined storage location (storage process). If the bottle container 10 has any defect while the case 100 is being stored in this manner, fuel gas (fuel gas generated by volatilization of liquid fuel) due to the internal fuel (methanol) leaks from the defect. . The fuel gas remains in the case 100 without immediately diffusing.

  The case 100 stored in the storage location is sequentially supplied to an inspection system as shown in FIG. In FIG. 3, a case 100 in which a plurality of bottle containers 10 to be inspected are accommodated is conveyed in a predetermined direction A by a conveyor 20 (conveyance mechanism). A photoelectric switch 25 for detecting that the case 100 is in the inspection position is installed at a predetermined conveyance position of the conveyor 20.

  In addition, an air cylinder 30 (nozzle drive mechanism) is installed at the inspection position so as to be disposed above the conveyor 20, and the combustible gas sensor 31 and the air pump 32 ( The suction mechanism) moves up and down. A nozzle 33 extending downward is provided at the tip of the air pump 32, and the gas sucked from the tip of the nozzle 33 by the air pump 32 is guided to the combustible gas sensor 31. The combustible gas sensor 31 has a strong detection sensitivity with respect to a fuel gas generated by volatilization of the fuel (methanol) filled in the bottle container 100, and the fuel gas contained in the introduced gas is detected. A detection signal having a level corresponding to the density (amount) is output. The air cylinder 30 passes the nozzle 33 provided in the air pump 32 through the retracted position above the case 100 at the inspection position and the through hole 101 (see FIG. 2) formed in the upper lid 100a of the case 100. The flammable gas sensor 31 and the air pump 32 are moved up and down so as to be reciprocated between the set position inserted into the inside.

  An air cylinder 21 is installed at a predetermined position below the conveyor 20. The air cylinder 21 moves up and down between a position where the stopper 22 protrudes above the conveyor 20 and a position where the stopper 22 is buried below the conveyor 20. With the stopper 22 protruding above the conveyor 20, the case 100 conveyed by the conveyor 20 is reliably stopped at the inspection position.

  The control system in this inspection system includes a control unit (CPU) 50, an analog / digital converter (A / D converter) 51, an input / output circuit 52, and a setting / display unit 53. The control unit 50 acquires the detection signal from the combustible gas sensor 31 as a digital signal via the A / D converter 51. A signal from the photoelectric switch 25 is supplied to the control unit 50 via the input / output circuit 52. Then, the control unit 50, based on the input signal and the detection signal, the exclusion device 60 and other driving devices (the solenoid valve for operating the air cylinders 30 and 21; the air pump 32; Control signals are generated for the conveyor 20 and the like, and the control signals are supplied to the exclusion device 60 and other driving devices via the input / output circuit 52. The setting / display unit 53 outputs a signal based on the operation of the operator to the control unit 50, and displays various information based on the display signal from the control unit 50.

  The control unit 50 performs processing according to the procedure shown in FIG.

  As described above, the case 100 sequentially put into the conveyor 20 through the storage process is conveyed toward the inspection position by the conveyor 20. In such a situation, the control unit 50 determines whether or not the case 100 in which the bottle container 10 to be inspected is in the inspection position based on the detection signal from the photoelectric switch 25 (S1). . When it is determined that the case 100 is in the detection position based on the detection signal from the photoelectric switch 25 when the case 100 conveyed by the conveyor 20 reaches the inspection position (YES in S1), the control unit 50 The air cylinder 21 is operated to cause the stopper 22 to protrude above the conveyor 20 (S2) and to stop the conveyor 20 (S3). As a result, the case 100 stops at the inspection position.

  Thereafter, the control unit 50 drives the air cylinder 30 to lower the combustible gas sensor 31 and the air pump 32 so that the nozzle 33 is at the set position (S4). Accordingly, the nozzle 33 is inserted into the case 100 through the through hole 101 (see FIG. 2) formed in the upper lid 100a of the case 100 that stops at the inspection position. In this state, the control unit 50 operates the air pump 32 (S5). Thereby, the gas in the case 100 is sucked from the tip of the nozzle 33 by the air pump 32 and guided to the combustible gas sensor 31. The combustible gas sensor 31 outputs a detection signal having a level corresponding to the concentration of the fuel gas contained in the introduced gas (gas detection step).

  After starting the operation of the air pump 32, the control unit 50 activates an internal timer and determines whether or not the timer has reached a predetermined time based on the detection signal from the combustible gas sensor 31. Then, the fuel gas concentration D is calculated, and it is determined whether or not the gas concentration D has reached the reference concentration Do (S6, S7, S8) (determination step). The control unit 50 repeatedly executes this processing (S6, S7, S8) for the predetermined time.

  When the fuel gas concentration D reaches the reference concentration Do (NO in S7, YES in S8) in the course of the process, the control unit 50 is airtight of any of the plurality of bottle containers 10 accommodated in the case 100. Assuming that the property is not appropriate, a predetermined exclusion process (S9) is executed. In this exclusion process, an exclusion control signal is given to the exclusion device 60. Then, the control unit 50 stops the air pump 32 (S10) and drives the air cylinder 30 to raise the combustible gas sensor 31 and the air pump 32 so that the nozzle 33 is pulled out of the case 100 and is in the retracted position (S11). Further, the air cylinder 21 is driven to bury the stopper 22 below the conveyor 20 (S12). Thereafter, the control unit 50 drives the conveyor 20 (S13), and determines whether or not the next case 100 has reached the inspection position (S1).

  When the conveyor 20 is driven, the case 100 is conveyed further downstream from the inspection position. Then, as described above, when the exclusion device 60 to which the exclusion control signal is given from the control unit 50 detects the case 100 on the conveyor 20, it excludes the case 100 from the conveyor 20, for example, by pushing it out.

  In the process of the control unit 50 described above (S6, S7, S8), the concentration D calculated based on the detection signal from the combustible gas sensor 31 reaches a point when the timer time reaches a predetermined time (S7). If the reference concentration Do is not reached (NO in S8), the control unit 50 determines that all the bottle containers 10 in the case 100 have no leak of fuel gas and the airtightness is appropriate. The above-described processes (S10 to S13) are executed without executing the exclusion process (S9). As a result, the case 100 is transported from the inspection position through the installation position of the exclusion device 60 to the next downstream process (for example, a loading process) by the conveyor 20.

  In the method for inspecting the airtightness of the bottle container 10 as described above, if the fuel gas leaks from at least one of the plurality of bottle containers 10 accommodated in the case 100, the fuel gas does not diffuse immediately and the case 100. Since the fuel gas is contained in the gas that is collected in the case 100 and sucked from the case 100, the plurality of containers 10 accommodated in the case 100 based on the detection result (gas concentration D) of the fuel gas The suitability of the airtightness can be determined collectively. Then, in order to detect fuel gas leaking from extremely small defects such as pinholes, for example, even if the determination time of airtightness suitability (predetermined time in S7) in the process of FIG. In addition, since the plurality of bottle containers 10 in the case 100 are collectively determined as to whether or not the airtightness is appropriate, it is possible to prevent a decrease in the inspection efficiency as much as possible.

  Furthermore, since the case 100 containing the plurality of bottle containers 10 is temporarily stored, the fuel gas leaking from a very small defect such as a pinhole in any of the plurality of bottle containers 10 housed in the case 100 Even if the flow rate is small, more fuel gas leaks in the case 100 while the case 100 is being stored. For this reason, even if the determination time of the airtightness propriety in the process mentioned above is comparatively short, the airtightness defect of the some bottle container 10 can be determined accurately.

  Note that the storage time of the case 100 in the storage process can be determined as appropriate based on the assumed defect size, the nature of the leaking gas, the detection accuracy of the combustible gas sensor 31, and the like.

  Further, before reaching the step of detecting the fuel gas contained in the gas in the case 100 (gas detection step), for example, a processing step as shown in FIG. 5 may be performed.

  The bottle container 10 that has undergone the fuel filling process is conveyed to the container accommodation process by the bottle conveying conveyor 20a. The bottle transporting conveyor 20a is provided with a heating device 70 so that the bottle container 10 transported by the bottle transporting conveyor 20a is heated before reaching the container housing process (heating process). A predetermined number of bottle containers 10 coming out of the heating device 70 are sequentially stored in the case 100 (container storing step). Thus, the case 100 in which the predetermined number (plurality) of bottle containers 10 are accommodated is put into the case transport conveyor 20b and transported toward the inspection position.

  When each bottle container 10 is heated by the heating device 70, the temperature of the fuel (methanol) in the plurality of bottle containers 10 accommodated in the case 100 is higher than the temperature at the time of filling (for example, 5 ° C. to 20 ° C.). It is high (for example, 20 ° C. to 50 ° C.). And the several bottle containers 10 in case 100 thrown into case conveyance conveyor 20b maintain the fuel which is the content at comparatively high temperature.

  Two reversing devices 80 are installed at predetermined positions up to the inspection position of the case conveyor 20b. The reversing device 80 on the upstream side reverses the case 100 conveyed by the case conveying conveyor 20b upside down (case reversing step). Therefore, the case 100 coming out of the reversing device 80 is conveyed in a state where the upper and lower sides with the upper lid 100a on the lower side are reversed. Then, the reversing device 81 on the downstream side reverses the upper and lower sides of the case conveyed by the case transporting conveyor 20b in the inverted state (case reversing step). Accordingly, the case 100 coming out of the reversing device 81 is transported toward the inspection position in an original state with the upper lid 100b on the upper side.

  When the case 100 reaches the inspection position where the air cylinder 30 is installed in this way, it is accommodated in the case 100 at the inspection position in accordance with the control similar to the control unit 50 described above (see the processing flow of FIG. 4). Further, processing (gas detection process, determination process) related to the airtightness inspection of the plurality of bottle containers 10 is executed.

  As described above, when each bottle container 10 is heated and accommodated in the case 100, the temperature of the fuel in the plurality of bottle containers 10 accommodated in the case 100 conveyed by the case conveyance conveyor 20b is higher than the temperature at the time of filling. Therefore, the expansion and vaporization of the fuel in each bottle container 10 in the case 100 is promoted before the case 100 reaches the detection position. For this reason, when the bottle container 10 has a defect, the fuel gas leaks from the defect, and even if the defect is an extremely small defect such as a pinhole, the detection of the fuel gas at the inspection position is performed. Based on the results, it becomes possible to more accurately determine the airtightness of each bottle container 10.

  The timing of heating each bottle container 10 may be any temperature as long as each bottle container 10 accommodated in the case can be maintained at a relatively high temperature until it reaches the inspection position. After housing, each bottle container 10 may be heated by heating the entire case 100. However, in the case where the entire case 100 is heated in this way, the case 100 becomes a heat insulating material and takes time to increase the temperature of the contents (fuel) of the bottle container 10, so that efficient heating is possible. As described above, each bottle container 10 is preferably heated before being accommodated in the case 100.

  Further, as described above, when the case 100 is transferred to the inspection position while being inverted, a defect formed in the bottle container 10 in the case 100 in the process of transferring the case 100 is likely to leak fuel gas at least temporarily. There is a high probability of being turned. For this reason, even if the defect formed in the bottle container 10 is an extremely small defect such as a pinhole, it is possible to more accurately determine the airtightness of each bottle container 10 based on the detection result of the fuel gas at the inspection position. Will be able to.

  In the example (see FIG. 5) in which the bottle container 10 is heated and the case 100 is inverted (see FIG. 5), the case 100 is not particularly stored after the bottle container 10 is accommodated in the case 100. The case 100 may be temporarily stored after the heated bottle container 10 is accommodated in the case 100. In this case, the length of the case transport conveyor 20b can be shortened and the transport speed can be set fast.

  Further, in the inspection method described with reference to FIGS. 1 to 4, the storage step can be omitted by securing a relatively long determination time (see S7 in FIG. 4). Even in this case, since a plurality of bottle containers 10 in the case 100 are collectively checked for proper airtightness, it is possible to prevent a reduction in inspection efficiency as much as possible.

  As described above, the present invention has the effect that it is possible to find an airtight defect due to an extremely small defect such as a pinhole while preventing a decrease in inspection efficiency as much as possible, such as a volatile liquid or a gas. The present invention is useful as a method for inspecting airtightness of a container filled with contents and an airtightness inspection system for a container used in the method.

It is a figure which shows the container accommodation process and storage process in the airtightness test | inspection method of the container which concerns on one Embodiment of this invention. It is a figure which shows the partial structure of the upper cover of the case used at a container accommodation process. It is a figure which shows the system which performs the gas detection process and determination process in the airtightness inspection method of the container which concerns on one Embodiment of this invention. It is a flowchart which shows the process sequence in the control unit in the system shown in FIG. It is a figure which shows another example of the process process until it reaches a gas detection process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bottle container 20 Conveyor 20a Bottle conveyance conveyor 20b Case conveyance conveyor 21 Air cylinder 22 Stopper 25 Photoelectric switch 30 Air cylinder 31 Flammable gas sensor 32 Air pump 33 Nozzle 50 Control unit 51 Analog-digital converter (A / D converter)
52 Input / Output Circuit 53 Setting / Display Unit 60 Exclusion Device 70 Heating Device 80, 81 Inversion Device 100 Case 100a Top Cover 101 Through Hole 110a, 110b Shutter Plate

Claims (7)

A container housing step of housing a plurality of containers containing contents in a case, and covering and fixing an upper lid having a shutter plate covering a through hole on the opened upper surface of the case ;
A gas detection step of sucking the gas in the case containing a plurality of containers with a nozzle that spreads the shutter plate and enters the case, and detects gas resulting from the contents of the container from the sucked gas When,
And a determination step of determining suitability of the plurality of containers accommodated in the case based on a detection result in the gas detection step.   The container airtightness inspection method according to claim 1, further comprising a storage step of temporarily storing the case in which the plurality of containers are accommodated before the gas detection step.   The heating step of heating each container so that the temperature of the contents of each of the plurality of containers accommodated in the case becomes higher than the temperature at the time of filling before the gas detection step. The method for inspecting airtightness of a container according to 1 or 2.   4. The container airtightness inspection method according to claim 3, wherein the heating step is performed before the container storing step.   The container airtightness inspection method according to any one of claims 1 to 4, further comprising a step of moving the case so as to change its posture between the container housing step and the gas detection step.   6. The container airtightness inspection method according to claim 5, wherein the step of moving the case includes a case reversing step of turning the case upside down.   7. The container airtightness inspection method according to claim 6, wherein in the case reversing step, the case is flipped up and down several times.

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