JPH03180733A - Gas leak inspection device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device for inspecting gas leakage, particularly a unit for inspecting leakage gas (carbon dioxide gas) from the top of the mouth of a draft beer barrel container, etc. The present invention relates to a gas leak testing method and a gas leak testing device.

[Conventional technology]

BACKGROUND ART Conventionally, for example, in draft beer barrel containers that require airtightness after being filled with fluid, a thorough gas leak inspection is usually performed at the shipping stage.

Conventionally, as a device for performing a gas leak test, for example, the 8th
A leak testing device for a beer barrel container 9 as shown in the figure has been proposed.

This device has an inspection head section 100, which is the main part of leak inspection.
The inspection head section 100 includes a seal member 101 and a cylindrical body 10 into which the seal member 101 is fitted.
2, a conductivity sensor 132 hanging inside the cylindrical body 102, and a supply pipe 110 for supplying pure water W into the cylindrical body 102.

That is, the tip of the inspection head 100 is provided with a ring-shaped seal member 101 that may come into direct contact with the mouth top surface 9a of the beer barrel container 9 as shown in the figure, and the rear part of this seal member 101 is The support body 102, the sealing member 101, and the mouth top surface 9a of the beer barrel container 9 form a so-called container. can be stored.

The rear end 102b of the cylindrical support body 102 is connected to the biasing spring 1
04, and the other end of the guide shaft 103 is connected to a frame 120.
is connected to the bottom surface of.

A conductivity measuring device 130 is fixed to the lower surface of the frame 120, and a conductivity sensor 13 is connected to the conductivity measuring device 130.
2 is hanging down.

Further, a supply pipe 110 for supplying pure water W is fixed to the frame 120 (the supply source of the pure water W is not shown). On the other hand, an air cylinder (not shown) is attached to the upper surface of the frame 120 via a cylinder rod 140, so that the entire inspection head 100 can move up and down.

According to such a conventional device, a cylindrical inspection head 100 is brought into contact with the mouth top surface 9a of a beer barrel container 9 to form a container, and pure water W is stored in the container. By measuring the conductivity of the pure water W, leakage of beer (leakage of carbon dioxide gas) is detected. Note that beer leakage occurs when there is a defect in the ring-shaped seal packing 9b.

[Problems to be Solved by the Invention] However, in the conventional inspection method, conductive impurities may be mixed into the pure water W, and cleaning of the mouth top surface 9a and the inspection head section 100, which is usually performed before and after inspection. If this is insufficient, a problem arises in that even normal barrels are erroneously detected as leaking barrels.

In addition, the distance between the cleaning device (not shown) for cleaning the mouth top surface 9a of the beer barrel 9 and the inspection device (inspection head section) is usually several meters or more because beer needs time to leak and accumulate. There is also the problem that space efficiency is poor as the two have to be separated from each other.

The present invention has been made in view of these circumstances, and its purpose is to solve the above problems, to provide a gas leakage detection unit that can reliably detect leakage gas, has a compact structure, and requires little maintenance. The aim is to provide the following.

[Means to solve the problem]

In order to solve the above problems, the inspection unit of the present invention has an inspection head that comes into contact with the inspection surface of the object to be inspected, and an outlet and an inlet that communicate with the inner cavity provided at the tip of the head, respectively. A circulation path formed by connecting pipes, a circulation device for forcibly circulating gas in the circulation path, and a gas leak connected to the circulation path for detecting the concentration of leaked gas in the circulation path. The gas leak detector is configured to include a detector and a calculation section that measures and calculates the leak gas concentration detected by the gas leak detector.

Further, the inspection method of the present invention includes: bringing the inspection head portion having the inner cavity into contact with the inspection surface of the object to be inspected to form a space portion including the inner cavity portion of the inspection head portion above the inspection surface; Forcibly circulating the gas in a circulation path provided in communication with the space, and measuring the leakage gas concentration in the circulation path,
The system is configured to perform calculations and determine whether or not the gas leakage of the object to be inspected is good or bad.

In addition, in this inspection method, before bringing the inspection head into contact with the inspection surface of the inspection object, the concentration of the inspection target gas in the atmosphere is measured in advance, and this measured value is used as a reference point, and the inspection is performed from this point. The system was configured to determine leakage based on the amount of increase in target gas concentration.

Further, the inspection head section is brought into contact with the inspection surface of the object to be inspected to form a space section including the inner cavity of the inspection head section above the inspection surface, and the space section is communicated with the space section. The gas in the circulation path provided is replaced with outside air or stable air containing the same concentration of the gas to be tested, and then the gas in the circulation path provided in communication with the space is forced. In addition to circulating the leak gas in the circulation path, the leak gas concentration in the circulation path is measured and calculated to determine whether the gas leak to be inspected is good or bad.

In addition, the inspection device of the present invention includes a transport device for placing and transporting a container to be inspected, and a transport device installed adjacent to a transport path of the transport device to center the transported container and temporarily hold it in a predetermined position. A gas leak inspection device that includes a centering unit for stopping the container, and a gas leak inspection unit that is located above the container aligned by the centering unit and comes into contact with the inspection surface of the inspection target to inspect for gas leaks. The centering unit includes a rotatable pivot arm that engages with a side surface of the container for positioning.
The gas leak inspection unit is formed by connecting circulation pipes to an inspection head that comes into contact with the inspection surface of the object to be inspected, and an outlet and an inlet that communicate with the inner cavity provided at the tip of the head. a circulation path, a circulation device for forcibly circulating gas in the circulation path, a gas leak detector connected to the circulation path for detecting the concentration of leaked gas in the circulation path, and a gas leak detector for detecting the concentration of leaked gas in the circulation path; and a calculation unit that measures and calculates the concentration of leak gas detected by the leak detector.

[Effect]

In the gas leak test of the present invention, an inspection head having a lumen is brought into contact with the inspection surface of the object to be inspected to form a space containing the lumen of the inspection head above the inspection surface,
The gas in the circulation path provided in communication with the space is forcibly circulated, and the leakage gas concentration in the circulation path is measured and calculated to determine whether the gas leakage of the object to be inspected is good or bad.

As a result, leakage gas can be detected reliably, and there is no need for time to collect leakage after cleaning the cap.
This eliminates the need for space between the cleaning device and the inspection device, making the structure itself more compact.

In addition, in this inspection, before bringing the inspection head into contact with the inspection surface of the inspection object, the concentration of the inspection target gas in the atmosphere is measured in advance, and this measurement value is used as a reference point, and the inspection target gas concentration from this point is measured. Leakage can be determined based on the amount of increase in concentration, or the inspection head may be brought into contact with the inspection surface of the object to be inspected to form a space above the inspection surface that includes the inner cavity of the inspection head, and the space may be The gas in the space and the circulation path provided in communication with the space is replaced with outside air or stable air containing the same concentration of the gas to be tested, and then,
By forcibly circulating the gas in the circulation path provided in communication with the space, measuring and calculating the leakage gas concentration in the circulation path, and determining whether the gas leakage of the object to be inspected is good or not. Measurement accuracy is further improved.

〔Example〕

Embodiments of the present invention will be specifically described below with reference to FIGS. 1 to 7. In this example, beer barrel containers (hereinafter referred to as
(referred to as seed container 9) is the container to be tested for leakage (inspection object).
It will be explained as follows.

FIG. 1 shows a plan view of a gas leak testing device 1 of the present invention, and FIG. 2 shows a front view thereof.

In these figures, a device 1 is provided with a conveying device having a belt with a chain 2°2.2 for conveying a seed container 9 from the right to the left, and a conveying device which is installed adjacent to the conveying path of the conveying device and is conveyed. A pair of arms 10 for temporarily stopping the barrel 9. A rotating arm 30 provided oppositely across the conveyance path on both sides of the conveyance path at approximately the center of the conveyance path.
a, 30a.

30b, a centering unit C having 30b, and a centered seed container 9 located above the center of the conveyance path.
A gas leakage testing unit L (FIGS. 1 and 3) is provided which tests for gas leakage from the seed container 9 while being in contact with the mouth top surface 9a of the seed container 9.

The transport device is configured as follows.

That is, at both ends of the device in the conveyance direction, a drive shaft 4a and a driven shaft 4b are provided with bearings 5a, respectively.

5a, 5b, 5b, and these shafts 4a, 4b have sprocket sockets 3a, 3, respectively.
a, 3a, 3b, 3b, and 3b are fitted at approximately equal intervals, and a belt with chain 2 is suspended endlessly from each of the sprockets 3a and 3b that form a pair in the conveying direction.

A drive sprocket 6 is fitted onto one end of the drive shaft 4a, and the drive sprocket 6 is driven by a drive motor 7.

A stopper unit S for temporarily stopping the seed container 9 being transported is usually provided on the entrance side of such a transport device. This unit S has a pair of rotating arms 10.10 placed opposite each other across a conveyance path, and these act together to perform functions such as locking and opening the seed container 9. There is. Contact rollers 13, 13 are rotatably mounted above the tip 7 portion 12.12 of the rotary arm 10.10.
One end of a pivot shaft 14.14 is vertically fitted into the arm base 11.11 of 10. This rotating shaft 14.14 is supported by a bearing 'L5゜■6,
A pulley 17 is fitted to the other end of the rotating shaft 14.14, and this pulley 7 is attached to the rotating shaft 14.14.
A drive belt is wound around it to rotate it.

By rotating this drive belt in the forward or reverse direction, the rotating arm 10.10 rotates within a predetermined angle range about the rotating shaft ↑4°14. When the arms 10.10 respectively rotate to the maximum toward the conveyance path side, the tip portions 12.12 of the arms come into contact with the outer circumferential side of the seed container 9, and temporarily lock the seed container. There is. Then, after a predetermined period of time has elapsed, the arms ↓0, 10 are rotated to the outside of the conveyance path, the locking with the seed container 9 is released, and the seed container 9 is conveyed again by the conveyance device.

Further in the transport direction of such a stopper unit S, a centering unit C is provided for centering and temporarily locking the seed container 9 being transported.

This unit C has - sets of rotating arms 30a on both sides of the conveyance path.

30b, a set of pivoting arms 30a,
30b are placed opposite each other across the conveyance path.

As shown in the figure, the pair of rotating arms 30a and 30b placed opposite each other across the conveyance path have the same configuration, so only one set installed on one side of the conveyance path will be described below.

That is, the arm base 31 of the rotating arms 30a, 30b
a, 31b have vertically rotating shafts 34a, 34b.
is passed through the shaft, and gears 40a and 40b are fitted to the upper end of the gear 40a.

40b are intermeshed with each other. In addition, rotation shaft 3
4a and 34b are each supported by a pair of bearings 35 and 36, a pulley 37 is fitted to the lower end of one of the shafts 34a, and a drive belt is wound around the pulley 37. The lower end of the other shaft 34b is supported by a bearing 39. The arm tip portions 32a of the rotating arms 30a, 30b rotate in accordance with the predetermined rotation of the rotating shafts 34a, 34b.

Shafts 41a and 41b are inserted through 32b, and contact rollers 33a are provided at the upper and lower ends of the shafts, respectively.

33b is rotatably attached.

By rotating the drive belt 38 in the forward or reverse direction, the rotating shaft 34a1 having the pulley 37 is connected to the rotating arm 30 via the gears 40a, 40b.
a and 30b respectively rotate within a predetermined angle range, and when the tips 32a and 32b of these arms 30a and 30b respectively rotate toward the conveyance path, they abut against the outer circumferential side of the tank container 9 and clamp the tank container. do. As described above, this set of rotating arms is installed in the same way as the other set across the conveyance path, so there are a total of four rotating arms 30a, 30a,
The outer circumferential side surface of the tank container 9 is clamped from four sides by the 30b, 30b, so that the tank container 9 is centered at a predetermined position on the conveyance path and held there until a gas leakage test described later is completed.

A gas leak inspection unit L is installed above the tank container 9 that is centered and locked in this manner.

The gas leak inspection unit L will be explained with reference to FIGS. 3 to 5.

FIG. 3 is a side view of FIG. 2, and FIGS. 4 and 5 are enlarged cross-sectional views of the inspection head section 60 of the unit L, and the inspection head section 60 further includes a piping system, detection, calculation section, etc. FIG.

In Fig. 3, the frame F is erected from both sides of the conveyance path.
4. A first cylinder 50 is vertically fixed via a cylinder bracket 51 to a substantially central portion of the frame F2, which is connected and installed on Fl.

A cylindrical inspection head section 60 is connected to the cylinder head of this cylinder 50.

The shape of the inside of the tip of the head section 60, that is, the inside of the tip of the head section 60 that comes into contact with the top surface 9a of the opening of the tank container 9 to be inspected (which has a sliding seal surface with a possibility of leakage) is as follows. , two members 62.6 as shown in FIG.
It is formed by a combination of 8.

That is, a ring-shaped protrusion 61 is provided inside the tip recess E of the head base 68, and a hem 62a is provided between the outer peripheral surface of the protrusion 61 and the inner peripheral surface of the recess tip recess E. A ring-shaped fitting member 62 is incorporated therein.

The portion where the top surface 9a of the mouth of the tank container 9 to be inspected comes into contact is at the l line shown in the figure. Therefore, when the top surface 9a of the tank container 9 comes into contact with the top surface 9a, a lumen part 64 is formed inside the head part 60.

Two communication holes 66a, 66 communicate with this inner cavity 64.
An outlet hole 67a and an inlet port 67b are formed at the ends of the communicating holes 66a and 66b, respectively, and these are provided with circulation vibros 9a and 69.
b are concatenated. The other ends of the circulation vibros 9a and 69b are each connected to a carbon dioxide gas detector 7, such as an infrared absorption sensor.
0, and as a result, the circulation pipes 67a, 6
7b forms a series of closed circulation paths. In such a circulation path, an air pump 74 is installed as a circulation device for forcibly circulating the air in the circulation path.
Further, a measurement calculation section 75 is connected to the carbon dioxide gas detector 70. Note that a sealing member such as a cap gasket (not shown) is usually provided at the portion where the head portion 60 and the mouth top surface 9a of the tank container 9 come into contact.

The operation of such gas leak inspection unit L will be briefly explained below.

The inspection head 60 located above the tank container 9 fixed by the positioning unit descends and comes into contact with the mouth top surface 9a of the tank container 9, thereby creating a small sealed space above the inlet top surface 9a. A space including a lumen 64 is formed.

Thereafter, by operating the air pump 74, the gas in the circulation path including the inner cavity 64 is forcibly circulated, and the leakage gas concentration in the circulation path is measured and calculated to determine whether the leak to be inspected is good or not. to judge. Incidentally, leakage of carbon dioxide gas occurs when there is a defect in the ring-shaped seal packing 9b provided at the mouth of the tank container shown in FIG.

Among such measurement methods, the following methods are particularly preferred.

(1) Automatic zero adjustment method Measure the monocarbon dioxide concentration in the atmosphere before or during the descent of the inspection head 60, use this measured value as a reference point, and determine leakage based on the amount of increase in carbon dioxide gas from that reference point. . That is, this is a method of canceling the carbon dioxide concentration in the atmosphere surrounding the tank container.

(2) Lower the air displacement layer inspection head section 60 and check the mouth top surface 9 of the beer barrel 9.
After making contact with a and forming a circulation path, open a part of the circulation path to create an exhaust system, replace the air in the circulation path with outside air or a gas with a similar carbon dioxide concentration, and then check the leakage. How to do a gas test.

This air replacement method cannot be achieved with the piping system shown in FIG. 4, and requires, for example, an additional communication hole 66c communicating with the inner cavity 64, as shown in FIG. One end of the circulation vibro 9c is connected to the communication hole 66c, and the other end of the circulation vibro 9c is connected to the atmosphere or a gas cylinder with a constant concentration. A solenoid valve Sv1 is provided in the middle of the circulation vibro 9c, and by switching this solenoid valve SVI, outside air etc. can be appropriately introduced into the system (circulation path).

Further, a solenoid valve Sv2 is provided in the middle of a series of closed system circulation paths formed by the circulation vibros 9a and 69b, and by switching this solenoid valve SV2, the circulation path is switched between a closed system and an exhaust system. It has become. In this air replacement method, after the inspection head 60 comes into contact with the mouth top surface 9a of the tank container 9, first the solenoid valve SVI is opened, and the solenoid valve SV2 is set to the exhaust side, so that the inside of the circulation path is kept in the air for a certain period of time. Replace the gas with outside air.

Thereafter, the solenoid valve Sv1 is closed, the solenoid valve SV2 is set to the circulation side, and the inspection is performed while the pump 74 is operated.

As described above, by using the automatic zero adjustment method or the air displacement method, it works effectively against changes in the carbon dioxide concentration in the surrounding atmosphere, and it is possible to detect even minute leaks with extremely high accuracy and reliability. can.

In addition, in order to regulate each operation of each unit of the apparatus of the present invention described above, detection sensors 95 and 96.97°98 are respectively arranged at predetermined positions along the conveyance direction as shown in FIG. ing.

Next, the operation of the apparatus of the present invention described above will be explained, including the contents detected by the detection sensors 95, 96, 97, and 98.

As shown in FIG. 1, the tank container 9 is carried into a conveyance path formed by endless bells l-2, 2, 2 that move in the direction of arrow (A). At this time, the rotating arm 10.10 of the stopper unit S protrudes toward the conveyance path. The tank container 9 is temporarily locked by ↓0. Then, the detection sensor 95 detects whether or not there is a tank container 9 to be processed on the transport path. In addition to this detection, ■ Confirmation that the entire device (system) is in an operable state (e.g., gas supply, air pressure of cylinder drive air source, etc.) is performed, and if both of these conditions are met, the cycle will start. The movable arms 10, 10 are each rotated outward from the conveyance path (in the direction of the arrow (1 port)), and are disengaged from the tank container 9, and the tank container 9 is transported again. At the same time when the detection sensor 96 detects the completion of passage of the tank container 9, the rotating arms 1. I try to do that.

The presence of the tank container 9 transported into the area of the centering unit C is confirmed by the detection sensor 97. Then, the four rotating arms 30a, 30a, 30b
, 30b respectively rotate toward the conveyance path side (arrow (d) direction), and the sides of the tank container are held and positioned at four locations. In this case, if the container has a barrel shape, the center position of the container to be locked will be the same regardless of the outer diameter of the container.

Next, the stroke of the first cylinder 50 installed in the leak gas inspection unit L advances. As a result, as described above, the inspection head 60 located at the top of the tank container 9 descends and comes into contact with the mouth top surface 9a of the tank container 9, thereby creating a small sealed space above the inlet top surface 9a. A space including a lumen 64 is formed.

Thereafter, by operating the air pump P, the gas in the circulation path including the inner cavity 64 is forcibly circulated, and the leakage gas concentration in the circulation path is measured and calculated to determine whether the leak to be inspected is good or not. to judge. In this case, as mentioned above (1
) automatic zero adjustment method or (2) air displacement method can be adopted.

When the gas leakage test of the tank container 9 is completed in this way, the first cylinder 50 installed in the test unit L is moved back, and the test head part 60 is separated from the top surface 9a of the inlet part.

At the same time, the four rotating arms 30a, 30a, 30b, and 30b, which were holding the sides of the tank container 9, respectively rotate to the outside of the transport path, and the opened tank container 9 is transported again, and detected by the detection sensor 98. The rear end of the tank container is detected. Upon receiving this detection signal, the detection sensor 95 performs (1) detecting whether or not there is a subsequent tank container 9 to be processed on the conveyance path, and (2) bringing the entire apparatus (system) into an operable state. Confirmation is made that there is (e.g. gas supply, air pressure of cylinder drive air source, etc.)
If both of these conditions are met, the pivot arm 10.1
0 rotates outward from the conveyance path (in the direction of arrow (b))
. As a result, the engagement with the subsequent tank container 9 is released, and the subsequent tank container 9 is again transported to the area of the centering unit C, and the same operation as described above is repeated.

By the way, among the devices of the present invention, centering unit C
Another embodiment of is shown in FIGS. 6 and 7.

6 and 7 are a plan view and a front view of the centering unit C, respectively.

In this case, the cylinder head 80a of the cylinder 80 is connected to one end of the first link 82, the other end of the first link 82 is connected to one end of the second link 84, and the second link 80 is connected to one end of the first link 82.
The other end of the third link 86 is connected to one end of the third link 86, and the other end of the third link 86 is fitted onto the rotating shaft 34b.

Note that the rotation shaft 3 is located approximately at the center of the first link 82.
4a is fitted, and this point serves as a fulcrum. With such a link configuration, the four arms can be rotated simultaneously using one drive R (cylinder 80), and the structure is extremely simple.

〔Effect of the invention〕

The gas leak testing method of the present invention includes: bringing an inspection head having a lumen into contact with an inspection surface of an object to be inspected to form a space containing the lumen of the inspection head above the inspection surface; Gas in a circulation path provided in communication with the space is forcibly circulated, and the leakage gas concentration in the circulation path is measured and calculated to determine whether the leakage of the object to be inspected is good or bad. moreover,
The gas leak testing unit and gas leak testing device of the present invention include:
A configuration is provided to perform such an inspection method.

Therefore, leakage gas can be detected reliably, and there is no need to take time to collect leaks after cleaning the cap.Therefore, the structure itself is compact because there is no need for space between the cleaning device and the inspection device. . In particular, this tendency becomes more pronounced when (1) automatic zero adjustment method or (2) air displacement is adopted.

[Brief explanation of drawings]

1 to 3 are respectively a plan view, a front view, and a side view of the gas leak inspection device of the present invention, and FIGS. 4 and 5 are enlarged sectional views of the inspection head portion of the unit L, respectively. 6 and 7, which are schematic diagrams in which the inspection head section includes a piping system, detection, calculation section, etc., are a plan view and a front view of the centering unit C, respectively.
FIG. 8 is a front view of a conventional beer barrel container 9 leakage testing device. DESCRIPTION OF SYMBOLS 1... Gas leak inspection device, 2... Belt with chain, 3a, 3b... Sprocket, 4a... Drive shaft, 4b... Driven shaft, 5
a, 5b...Bearing, 6...Drive sprocket, 7.
... Drive motor, 9... Seed container, ↓0... Rotating arm, Work 3... Contact roller, 14... Rotating shaft,
15.16...Bearing, ■7...Pulley, 30a, 3
0b... Rotating arm, 33a, 33b-- Contact roller, 35.36-... Bearing, 40a, 40b- Gear, 50...
...First cylinder, 60...Inspection head section, 64...
・Inner cavity, 67a...outflow port, 67b...inflow port,
69a, 69b... Circulation pipe, 70... Gas leak detector, 75... Arithmetic unit, 95.96, 97.98.
...Detection sensor, S...Stopper unit, C...Centering unit, L...Gas leak inspection unit.

Claims (1)

[Scope of Claims] 1. Circulation pipes are connected to an inspection head part that comes into contact with the inspection surface of the object to be inspected, and an outflow port and an inflow port that communicate with the inner cavity provided at the tip of the head part, respectively. a circulation path formed; a circulation device that forcibly circulates gas in the circulation path; a gas leak detector connected to the circulation path and configured to detect the concentration of leaked gas in the circulation path; A gas leak inspection unit comprising: a calculation section that measures and calculates the concentration of leak gas detected by a gas leak detector; 2. Bringing the inspection head portion having the inner cavity into contact with the inspection surface of the object to be inspected to form a space portion including the inner cavity portion of the inspection head portion above the inspection surface, and communicating with the space portion. A gas leakage inspection method characterized by forcibly circulating gas in a provided circulation path, measuring and calculating the leakage gas concentration in the circulation path, and determining whether or not the gas leakage of an object to be inspected is good or bad. . 3. In the gas leakage inspection method according to claim 2, before bringing the inspection head part into contact with the inspection surface of the inspection object,
1. A gas leakage inspection method characterized by measuring the concentration of a gas to be inspected in an atmosphere in advance, using this measured value as a reference point, and determining a leak based on the amount of increase in the concentration of the gas to be inspected from this point. 4. The gas leak inspection method according to claim 2, wherein the inspection head is brought into contact with the inspection surface of the object to be inspected to form a space including the inner cavity of the inspection head above the inspection surface;
The gas in the space and the circulation path provided in communication with the space is replaced with outside air or stable air containing the same concentration of the gas to be tested, and then the gas in the space is communicated with the space. A gas leakage inspection method characterized by forcibly circulating gas in a provided circulation path, measuring and calculating the leakage gas concentration in the circulation path, and determining whether or not the gas leakage of an object to be inspected is good or bad. . 5. A conveyance device for placing and conveying containers to be inspected; and a centering unit installed adjacent to the conveyance path of the conveyance device for centering the conveyed containers and temporarily stopping them at a predetermined position. and a gas leak testing unit that is located above the container aligned by the centering unit and that tests for gas leaks by coming into contact with the inspection surface of the inspection target, the centering unit comprising: , a rotatable rotating arm that engages with the side surface of the container and performs positioning; a circulation path formed by connecting a circulation pipe to an outflow port and an inflow port communicating with the internal cavity, a circulation device for forcibly circulating gas in the circulation path, and a circulation device connected to the circulation path; A gas leak inspection device comprising: a gas leak detector for detecting the concentration of leak gas in a circulation path; and a calculation section that measures and calculates the concentration of leak gas detected by the gas leak detector. .