JP5102155B2 - Leak point detector - Google Patents

Description

  The present invention is, for example, a leak point detector that can be used for a leak test of various devices having a closed container such as a tank or a piping circuit for fluid delivery, such as a leak test of a refrigerant circulation circuit in a manufacturing process of a refrigerator or a cooler. About.

As an example of a leak point detector that can be used for a leak test of various devices having a tank or a fluid piping circuit such as a leak test of a refrigerant circulation circuit in a manufacturing factory such as a refrigerator or a cooler, the technology described in Patent Document 1 Can be mentioned as known examples.
The leak point detector (gas analyzer) described in Patent Document 1 includes a leak point search gas pipe (gas suction pipe), and a reference gas gas pipe for sucking a reference gas (for example, the atmosphere) around the search point. An infrared gas analyzer having a cuvette to which these gas pipes are selectively connected; and a solenoid valve for selectively connecting a leak point search gas pipe and a reference gas gas pipe to the cuvette of the infrared gas analyzer; A gas suction pump is used, and the gas led to the cuvette is switched by a solenoid valve, and due to the difference in the amount of infrared absorption due to the difference in the components of the gas sucked by the leak point search gas pipe and the gas sucked by the reference gas pipe The leak point is detected. In Patent Document 1, an infrared-active test gas is introduced into a device to be inspected, and a test gas contained in a gas sucked by a leak point search gas pipe is detected from a measurement value of an infrared absorption amount by an infrared gas analyzer. Thus, a technique for detecting a leak point is disclosed.
Special table 2004-515777 gazette

However, the above-described leak point detector described in Patent Document 1 has a configuration that requires two pipes for gas suction, a solenoid valve, and a control circuit for switching control of the solenoid valve, has a complicated structure, and costs. There was a problem that it was too expensive. In addition, the electromagnetic valve has a mechanical structure and has a drawback that it has a shorter life compared to other components such as electronic components.
In addition, this leak point detector is configured to alternately switch the connection of the leak point search gas pipe and the reference gas gas pipe to the cuvette in a short time by a solenoid valve, but the gas suction pump is continuously operated. Therefore, the life of the pump and the life of the battery power source were also affected.
Regarding battery power, if a small battery such as a dry battery (for example, one that conforms to IEC 80086 or JIS 8500) is used, it must be replaced in a short period of time. If a relatively large battery such as a lead-acid battery is used, the weight is large. This greatly affects the portability of the leak point detector.

  In view of the above problems, the present invention has an object to provide a leak point detector that can easily reduce the cost, extend the service life of a pump and a battery power source, and can stably secure the detection accuracy of the detection target gas. .

In order to solve the above problems, the present invention provides the following configuration.
1st invention introduces the test gas which has infrared activity into the inspection object member which is the airtight container or flow path piping, leak inspection which is used for the test which detects the leak location from the inspection object member of the test gas An infrared gas analyzer comprising a light emitter and a light receiver opposed to a cuvette, one leak point search gas pipe connected to the cuvette of the infrared gas analyzer, and the leak point search A leak point detector comprising: a pump for introducing gas from the tip of a gas pipe to the cuvette; and a pump drive control circuit for switching on / off the drive of the pump at a preset cycle. provide.
The second aspect of the invention further includes the infrared intensity received by the light receiver of the infrared gas analyzer during driving of the pump and the infrared intensity received by the light receiver during the drive stop time of the pump immediately before the start of pump driving. And a comparison detection unit for outputting a test gas detection signal when the infrared intensity during driving of the pump is lower than the infrared intensity immediately before the start of driving. I will provide a.
3rd invention comprises the alerting | reporting part which outputs the alerting | reporting information for alert | reporting that the test gas was detected based on the test gas detection signal output from the said comparison detection part, It is characterized by the above-mentioned. The leak point detector according to the second aspect of the present invention is provided.
According to a fourth aspect of the present invention, the driving of the pump by the pump driving control circuit is switched on and off in a period of 0.5 to 1 second per cycle with a pump driving stop time of 0.3 to 0.5 seconds. A leak point detector according to any one of the first to third aspects is provided.
5th invention is provided with the movement operation part in which the front-end | tip part of the said leak point search gas pipe extended from the said cuvette can be manually moved, Any 1st-4th characterized by the above-mentioned An inventive leak point detector is provided.

The leak point detector according to the present invention can be suitably used for detecting a leak point that generates a small amount of leak gas of, for example, several g / year.
The pump drive control circuit is configured to switch on / off the drive of the pump at a preset cycle, and the infrared intensity received by the receiver of the infrared gas analyzer during the drive of the pump and the above-mentioned immediately before the start of the pump drive It is possible to grasp the presence of a leak point (detect a leak point) from comparison with the infrared intensity received by the light receiver during the pump drive stop time.
For example, a storage unit is provided for storing the intensity of infrared rays received by the light receiver of the infrared gas analyzer during the stoppage of the drive immediately before the start of the pump. Then, when the pump enters the drive state (drive time) from the drive stop state, the infrared absorption amount stored in the storage unit and the intensity of the infrared ray received by the receiver of the infrared gas analyzer during the pump drive are obtained. Compare.

  Further, according to the leak point detector of the present invention, there is only one leak point search gas pipe for sucking gas from around the inspection target member by driving the pump and introducing it into the cuvette of the infrared gas analyzer. Since the gas pipe for reference gas provided in the leak point detector of the prior art (Patent Document 1) is not provided, the received light intensity of the infrared light in the light receiver when the pump is stopped and the infrared light in the light receiver when the pump is driven Both the measurement and comparison of the received light intensity are performed on the gas introduced from the leak point search gas pipe into the cuvette of the infrared gas analyzer. Gas is introduced into the cuvette only from the leak point search gas pipe.

Further, in the present invention, when the leak point is a minute leak point where the leak amount of the test gas is as small as several g / year, the drive stop time is set between the pump drive times by the pump on / off control. As a result, a retention part in which the test gas leaked from the leak point stays can be generated near the leak point. A minute leak point can be detected efficiently by sucking the test gas in the staying portion when the pump is driven after the drive stop time has elapsed due to the on / off control.
With respect to detection of a leak point with a leak amount of about several g / year, if the pump drive stop time is 0.3 to 0.5 seconds as in the fourth aspect of the invention, suction by pump drive is performed. After the stagnation part disappears due to the operation, the stagnation part having a size that can reliably detect the leak point can be generated again during the drive stop time, and a minute leak point can be detected efficiently.

  In the case of gas suction from the vicinity of the leak point where the amount of leak is as small as several g / year, the test gas concentration in the cuvette is after the test gas stay near the leak point disappears due to suction operation by driving the pump. The gas in the cuvette of the infrared gas analyzer is lowered by being replaced with the gas introduced into the cuvette after the staying portion disappears (see FIG. 4). Replacing the gas in the cuvette of the infrared gas analyzer with the gas introduced into the cuvette after disappearance of the staying portion contributes to ensuring the detection accuracy of the test gas introduced into the cuvette after the replacement.

For example, in the case of the fourth invention, the driving of the pump is switched on and off at 0.5 to 1 second per cycle. The pump drive stop time is 0.3 to 0.5 seconds. The pump drive time is in the range of 0.2 to 0.5 seconds, the pump drive stop time is 0.3 to 0.5 seconds, and the pump drive on / off switching time is 0.00. 5 to 1 second is secured.
The time from the start of gas suction from the vicinity of the leak point to the time when the test gas concentration in the cuvette reaches the maximum value due to the suction of the test gas constituting the staying portion (see FIG. 4) is the volume of the cuvette of the infrared gas analyzer. Depends on the pump capacity (aspiration amount). In other words, the leak point detector according to the fourth aspect of the invention has a pump drive stop time of 0.3 to 0.5 seconds and a pump drive on / off switching time of 0.5. In this configuration, the volume of the cuvette of the infrared gas analyzer and the capacity (aspiration amount) of the pump are set so as to satisfy ˜1 second.

Since the leak point detector according to the present invention switches the driving of the pump on and off in 0.5 to 1 second per cycle, the pump is intermittently operated. Therefore, the life of the pump can be extended.
When the electric pump is driven by a battery power source, the pump is intermittently operated by intermittently supplying power from the battery power source to the pump. In this case, the battery power consumption can be reduced and the life of the battery power supply can be extended.

According to the fifth aspect of the present invention, it is possible to efficiently perform a leak point search operation for the inspection target member by moving the moving operation unit.
The moving operation unit may incorporate not only the tip of the leak point search gas pipe extending from the cuvette but also one or more of an infrared gas analyzer, a pump, and a pump drive control circuit, for example. It is also possible to provide the comparison operation unit according to the second invention and the notification unit according to the third invention in the movement operation unit, and to provide a battery power source for driving the electric pump in the movement operation unit.

  According to the leak point detector of the present invention, there is only one leak point searching gas pipe for sucking gas from around the member to be inspected by driving the pump and introducing it into the cuvette of the infrared gas analyzer. Since the gas pipe for reference gas provided in the leak point detector of the technology (Patent Document 1) is not provided, the configuration is simple. Also, unlike the prior art, there is no need for a solenoid valve that switches the connection of two pipes to the cuvette of the infrared gas analyzer, and a control circuit for switching control of the solenoid valve, thus simplifying the structure and reducing the cost. Can also be realized easily. There is no need to consider the life of the solenoid valve. Since the pump is switched on and off, the service life can be extended as compared with the case of continuous operation. The battery power source for driving the electric pump can also be extended. In addition, since a sufficient operating time can be secured with a small and light battery power source, a leak point detector excellent in portability can be easily obtained.

  Hereinafter, an embodiment of a leak point detector embodying the present invention will be described with reference to the drawings.

  FIG. 1 is a model diagram illustrating a configuration of a leak point detector 10 according to the present invention. FIG. 2 is an example of a leak point detector 10 including a detector main body 21 and a moving operation unit 22 that can be manually moved. FIG. 4 is an operation chart for explaining the operation of the leak point detector 10, and FIG. 5 is a diagram showing an example of the configuration of the comparison detection unit 15 of the leak point detector 10.

The leak point detector 10 is used for a leak test of various devices (devices to be inspected) having an airtight container such as a tank or a piping circuit for fluid transmission. For example, a refrigerant in a manufacturing process of a refrigerator or a cooler Used for leak test of circulation circuit.
In the leak test, a test gas G having infrared activity is introduced into a test target member 1 (see FIGS. 1 and 2) which is a sealed container or a flow pipe, and the test gas G leaks from the test target member 1. Is detected by using the leak point detector 10. The leak point detector 10 according to the present invention can be used for searching for the leak point R. The leak point detector 10 according to the present invention can be suitably used particularly for searching for a small leak point R that is difficult to confirm visually. By using this leak point detector 10, the presence or absence of a leak point of the inspection target member 1 can be inspected.
In addition, as the inspection target member 1, in addition to those requiring airtightness, those requiring watertightness may be employed. For example, an underground installation closure that stores a connection point of a communication cable installed underground may be a target.

As test gas G, it has infrared activity, for example, Freon gas and other halogen gas are employable.
In addition, when the gas introduced at the time of use of a member to be inspected has infrared activity, it is also possible to perform a leak test by treating the introduced gas itself at the time of use as a test gas.

  As shown in FIG. 1, the leak point detector 10 includes one leak point search gas pipe 11, an infrared gas analyzer 12 having a cuvette 12 a into which gas is introduced from the leak point search gas pipe 11, a leak The infrared intensity received by the point search gas pipe 11 and the pump 13 for introducing the outside air into the cuvette 12 a, the pump drive control circuit 14, and the light receiver 12 c (described later) of the infrared gas analyzer 12 is obtained from the infrared gas analyzer 12. The comparison detection unit 15 that is input and the notification unit 16 that outputs notification information for notifying that the test gas has been detected are provided.

The infrared gas analyzer 12 receives the infrared light output from the light emitter 12b, the light emitter 12b that outputs infrared light for measuring the amount of infrared absorption of the gas in the inner space 12s of the cuvette 12a, and the cuvette 12a. And a light receiver 12c.
The light emitter 12b and the light receiver 12c are disposed opposite to each other via the inner space 12s of the cuvette 12a.

The leak point search gas pipe 11 communicates with the cuvette 12 a of the infrared gas analyzer 12. The leak point search gas pipe 11 may be directly connected to and communicated with the cuvette 12a of the infrared gas analyzer 12, but may be connected to and communicated with the cuvette 12a via a flexible hose or the like.
The leak point detector 10 includes an exhaust pipe 17 extending from the cuvette 12a, and a pump 13 is connected to the exhaust pipe 17.

The pump 13 sucks the gas in the cuvette 12 a of the infrared gas analyzer 12. The suction force of the pump 13 acts on the leak point search gas pipe 11 communicating with the cuvette 12 a via the cuvette 12 a of the infrared gas analyzer 12.
In this leak point detector 10, by driving a pump 13 provided in the exhaust pipe 17, gas suction from the tip of the leak point search gas pipe 11 opposite to the cuvette 12 a and the leak point search gas pipe are performed. 11 is introduced into the cuvette 12a.
The installation position of the pump 13 is not limited to the exhaust pipe 17, and for example, in the middle of the leak point search gas pipe 11 or in the longitudinal direction thereof (end on the cuvette 12a side, opposite to the cuvette 12a) Any of the end portions of these may be used.

,
The pump drive control circuit 14 and the comparison detection unit 15 are provided in a control unit 18 for overall drive control of the leak point detector 10.

In the control unit 18 of the illustrated example, the pump drive control circuit 14 presets the drive of the pump 13 by controlling the drive of the switch 132 provided in the drive power supply circuit 131 of the electric pump 13. It performs the function of switching on and off in cycles.
The switch 132 opens and closes the driving power supply circuit 131.

The driving of the pump 13 is switched on and off by the pump driving control circuit 14 at, for example, 0.5 to 1 second per cycle.
The drive stop time of the pump 13 is 0.3 to 0.5 seconds. However, it goes without saying that it is set in a range shorter than the time required for one cycle.
By securing the drive stop time of the pump 13 for 0.3 seconds or longer, the stagnation part G near the leak point R (see FIG. 1) is sucked into the leak point search gas pipe 11 and disappears, and then the minute leak point R In the vicinity of (see FIG. 1), a retention portion G1 where the test gas G leaked from the leak point stays can be generated again. By sucking the test gas in this retention portion, the minute leak point R is reduced. It can be detected efficiently.

As shown in FIG. 5, the comparison detection unit 15 includes a storage unit 15a that stores the infrared intensity received by the light receiver 12c of the infrared gas analyzer 12 when the pump 13 is in a drive stop state, and a drive stop state. A comparison unit that compares the infrared intensity measured by the light receiver 12c of the infrared gas analyzer 12 with the infrared intensity stored in the storage unit 15a when the pump 13 is started. As a result of the comparison of the infrared intensity at 15b and the comparison unit 15b, the infrared intensity received by the light receiver 12c of the infrared gas analyzer 12 during driving of the pump 13 is lower than the infrared intensity stored in the storage unit 15a. An output unit 15c that outputs a test gas detection signal when the test gas concentration is high.
The infrared output of the light emitter 12b of the infrared gas analyzer 12 is constant.

The storage unit 15a updates and stores the infrared intensity received by the light receiver 12c of the infrared gas analyzer 12 every time the pump 13 whose driving is turned on / off by the pump drive control circuit 14 is stopped. However, the storage unit 15a stores the infrared intensity received by the light receiver 12c during the drive stop time of the pump 13 immediately before the start of driving. At this time, if there is already stored data (infrared intensity), it is updated to a new one to be stored.
The comparison unit 15b receives the infrared intensity received by the light receiver 12c of the infrared gas analyzer 12 and the infrared intensity stored in the storage unit 15a during the driving of the pump 13 which has started driving from the driving stop state, that is, the driving start. The measured value of the infrared intensity received by the light receiver 12c of the infrared gas analyzer 12 during the previous drive stop time of the pump 13 is compared.
As shown in FIG. 1, the output unit 15 c specifically outputs a drive command for the notification unit 16 as a test gas detection signal here. The notification unit 16 is driven based on this drive command and outputs notification information.

  In FIG. 1, the notification unit 16 is specifically a speaker device that outputs notification information by voice. The notification information is information for notifying the user of the leak point detector 10 of the detection of the test gas and the detection of the leak point R, and is not limited to voice information. The notification unit 16 is not limited to a speaker device, and may be, for example, a lamp that is turned on by a drive command, a liquid crystal display device that outputs notification information as image information (including character information), and the like.

The infrared gas analyzer 12 is configured to output a signal corresponding to the infrared absorption amount of infrared that has passed through the gas in the cuvette, in place of the configuration that outputs a signal corresponding to the infrared intensity received by the light receiver 12c. Also good.
In this case, the comparison detection unit 15 stores the storage unit 15a that stores the infrared absorption amount when the pump 13 is in the drive stop state, and the pump 13 when the drive in the drive stop state is started. The comparison unit 15b for comparing the infrared absorption amount measured during the driving and the infrared absorption amount stored in the storage unit 15a during the drive stop time of the pump 13 immediately before the start of driving, and the infrared absorption by the comparison unit 15b When the amount of infrared absorption measured while the pump 13 is driven is larger than the amount of infrared absorption stored in the storage unit 15a (the test gas concentration is high), the test gas detection signal is output. And an output unit 15c.

The leak point detector 10 according to the present invention may be a stationary type installed at a desired position, but may be a portable type that can be carried by the user, as will be described later.
In the case of the stationary type, for example, the leak point can be searched by moving the inspection target member with respect to the leak point search gas pipe 11 of the leak point detector.

A leak point detector 10A shown in FIG. 2 is an example of a portable leak point detector (first example of a portable leak point detector), and a drive power supply circuit 131 for driving the pump 13 (see FIG. 1). , A battery power source 133 (see FIG. 1), a detector main body 21 in which the control unit 18 (see FIG. 1) is incorporated in a housing, and a moving operation unit 22 that can be manually moved. .
The moving operation unit 22 includes an operation unit main body 221 in which the infrared gas analyzer 12, the pump 13, and the exhaust pipe 17 connected to the pump 13 are incorporated in a casing, and an intake pipe 222 protruding from the operation unit main body 221. It has. The intake pipe 222 functions as the leak point search gas pipe 11 of the leak point detector 10, and as shown in FIG. 3, the infrared gas analyzer in the casing 223 of the operation unit main body 221 is connected via the connection pipe 24. Twelve cuvettes 12a are communicated. FIG. 3 illustrates a configuration in which the casing 223 of the operation unit main body 221 is a plastic integrated product integrated with the intake pipe 222.
However, the connection form between the intake pipe 222 and the cuvette 12a of the infrared gas analyzer 12 is not limited to the configuration illustrated in FIG. 3. For example, a portion of the intake pipe 222 that extends into the operation portion main body 221 is directly communicated with the cuvette 12a. It is also possible to adopt a configuration such as that described above.

The detector body 21 is portable and can be carried by a user using a carrying aid such as the hanging strap 211.
The movement operation unit 22 is connected to the detector main body 21 via a flexible signal line cable 23 and can be easily moved and operated manually.

  The leak point detector 10A shown in FIG. 2 has a structure in which an intake pipe 222 that is narrower than the casing protrudes from one end in the axial direction (one end in the longitudinal direction) of the elongated cylindrical casing of the detector body 21. For example, it is easy to insert the intake pipe 222 into a narrow space in the apparatus 2 (inspection apparatus) in which the inspection target member 1 is incorporated to perform a leak test and search for a leak point.

  As the infrared gas analyzer 12 of the leak point detector 10, for example, a configuration in which a light emitter 12 b and a light receiver 12 c are disposed opposite to each other in the longitudinal direction of a cylindrical cuvette 12 a having a length of several tens to 200 mm is adopted. Can do. As the infrared gas analyzer 12, the smaller the volume of the cuvette 12a, the quicker the gas in the cuvette 12a can be replaced each time the pump 13 is driven by the on / off control. This is preferable. This contributes particularly effectively to the detection of a very small amount of test gas.

In the operation chart shown in FIG. 4, the horizontal axis is time.
Here, detection of a leak point at which a leak of a small amount of test gas of about several g / year existing in the inspection target member will be described.
In FIG. 4, “suction” indicates a state where the pump 13 is driven, and “stop” indicates a state where the drive of the pump 13 is stopped. However, “suction” specifically refers to when the driving current is supplied to the pump 13, and “stop” specifically refers to when the driving current is not supplied to the pump 13.

  The leak point detector 10 drives the pump 13 to drive the test gas leaked from the leak point in the vicinity of the leak point together with the gas (air) existing around the leak point from the tip of the leak point detector 10. The suction and introduction into the cuvette 12a increases the test gas concentration in the cuvette 12a.

  The infrared gas analyzer 12 emits infrared light from the light emitter 12b, receives light at the light receiver 12c, and inputs an infrared intensity measurement value received by the light receiver 12c to the control unit 18 (more specifically, a comparison detection unit). 15) is always performed.

  The comparison detection unit 15 stores the measurement value of the infrared intensity input from the infrared gas analyzer 12 in the storage unit 15a when in the “stop” driving stop state of FIG. Specifically, the storage unit 15a has a drive stop time (a time in the “stop” drive stop state of FIG. 4) preset in the control unit 18 (specifically, the pump drive control circuit 14). At the end, immediately before entering the “suction” state, the infrared intensity received by the light receiver 12c of the infrared gas analyzer 12 is stored. Further, in the repeated cycle (cycle) of “suction” and “stop”, the measured value of the infrared intensity stored in the storage unit 15a is updated every time the “stop” driving stop state in FIG. 4 is entered.

When the leak point detector 10 enters the “suction” driving state in FIG. 4, the leak point detector 10 starts inputting the measured value of the infrared intensity received by the light receiver 12 c of the infrared gas analyzer 12 to the comparison detector 15. Further, the comparison detection unit 15 starts comparison between the measurement value of the infrared intensity stored in the storage unit 15a and the measurement value (infrared intensity) input from the infrared gas analyzer 12 (more specifically, the comparison unit) Comparison at 15b).
When the measurement value of the infrared intensity input from the infrared gas analyzer 12 to the comparison detection unit 15 is smaller (lower) than the measurement value of the infrared intensity stored in the storage unit 15a, a notification is given from the output unit 15c of the comparison detection unit 15. A drive command is output to the unit 16, and the notification unit 16 that has received the drive command outputs notification information.

The leak point detector 10 may start a repeated cycle of “suction” and “stop” from the “stop” state (drive stop state) when the main power switch (not shown) is turned on and started. It is also possible to start from the “suction” state (driving state).
When starting from the former “stop” state, the infrared gas analyzer 12 emits infrared light from the light emitter 12b, receives light at the light receiver 12c, and controls the measured value of the infrared intensity received by the light receiver 12c. 18 (specifically, input to the comparison detection unit 15) is performed, and the measured value (infrared intensity received by the light receiver 12c) is stored in the storage unit 15a.

By the way, in the case of a leak point where a small amount of test gas leaks about several g / year, the test gas that leaks from the leak point and stays in the vicinity of the leak point is stored in the leak point search gas pipe 11 of the leak point detector 10. By sucking from the tip, it can be detected efficiently.
Hereinafter, gas suction, leak gas detection, and leak point detection by the leak point detector 10 from the vicinity of the leak point will be described.
In this case, since the amount of the test gas flowing out from the leak point is very small, the tip of the leak point search gas pipe 11 of the leak point detector 10 is brought close to this leak point, and the gas existing near the leak point is removed. When the test gas G staying part G1 (see FIG. 1), which is present near the leak point before suction, disappears, the amount of the test gas introduced into the cuvette 12a by suction stays in a very small amount.

As shown in FIG. 4, immediately after the start of suction (symbol a in FIG. 4, start of driving of the pump), the test gas constituting the staying part G1 is introduced into the cuvette 12a, and the test gas concentration in the cuvette 12a is reduced. It rises (the infrared intensity received by the light receiver 12c of the infrared gas analyzer 12 is lowered).
When the test gas staying portion G1 existing near the leak point before the suction disappears, the test gas concentration in the cuvette 12a begins to decrease (the infrared intensity received by the light receiver 12c of the infrared gas analyzer 12 increases). For this reason, a peak value of the test gas concentration appears (reference symbol b in FIG. 4). In other words, if the suction is continued even after the suction of the test gas staying in the vicinity of the leak point is completed, the suction of air containing almost no test gas, or substantially only the air is sucked, and the cuvette The test gas in 12a is purged and the test gas concentration decreases. By the end of the time of “suction” state (drive time), all the gas inside the cuvette 12a is replaced with the gas sucked after disappearance of the stay part G1, that is, the air containing almost no test gas (FIG. 4). Middle sign c).

The time per cycle of the “suction” and “stop” cycle of the leak point detector 10 is the time of the “suction” state, the suction of the test gas staying near the leak point, and the subsequent test gas. It is set so that the replacement with almost no air can be completed.
The retention of the test gas in the vicinity of the leak point has a limit in increasing the retention amount due to the diffusion of the test gas into the air. As a result of intensive studies by the present inventors, for example, when a pump 13 with an exhaust amount (suction amount) of 100 to 300 mL / min is used, a leak of a small amount of test gas of about several g / year occurs near the leak point. It was understood that the generated staying part G1 disappeared within 0.2 seconds from the start of suction.

In the present invention, the pump drive time (“suction” time in FIG. 4) is secured for 0.2 seconds or more, and the gas in the cuvette 12a is supplied to the retention portion by the suction duration time after the retention portion G1 disappears. The gas sucked after G1 disappears can be replaced. The length of the suction continuation time is preferably equal to or longer than the time from the start of suction to the disappearance of the staying portion G1 (however, it is preferable to set it as short as possible).
In the case of detecting a leak point where a leak of a small amount of test gas of about several g / year occurs, the “suction” time (pump driving time) in FIG. In this driving time (“suction” time in FIG. 4), the suction of the test gas staying in the vicinity of the leak point and the subsequent replacement with the air containing almost no test gas can be surely completed. As a result, when the driving is resumed after the pump 13 is stopped, the test gas can be detected with high accuracy, and a leak point of a small amount of test gas of several g / year is generated. Suitable for detection.

  When the pump 13 enters the “stop” drive stop state from the “suction” drive state in FIG. 4 (symbol d in FIG. 4), the introduction of the test gas to the cuvette 12 a is stopped. Test gas concentration does not increase.

When the pump 13 enters the “suction” drive state from the “stop” drive stop state in FIG. 4 (symbol a in FIG. 4), the suction is resumed.
As described above, at the end of the drive stop time, immediately before entering the drive state, the storage unit 15a of the comparison detection unit 15 stores the infrared intensity received by the light receiver 12c of the infrared gas analyzer 12. In the driving state, the measurement value of the infrared intensity stored in the storage unit 15a and the measurement value of the infrared intensity input from the infrared gas analyzer 12 to the comparison detection unit 15 after the start of driving are sent to the comparison detection unit 15. Compare. If the measurement value of the infrared intensity input from the infrared gas analyzer 12 to the comparison detection unit 15 after the start of driving becomes higher than the measurement value of the infrared intensity stored in the storage unit 15a, the notification information is output from the notification unit 16. The

  By securing the drive stop time, a test gas retention portion G1 is formed near the leak point. For this reason, the leak point can be reliably detected.

The measured value of the infrared intensity stored in the storage unit 15a while the drive was stopped was received by the light receiver 12c of the infrared gas analyzer 12 in a state where a gas (air) containing a small amount of test gas was introduced into the cuvette 12a. Infrared intensity. The comparison of the infrared intensity in the comparison detection unit 15 is performed using the measured value of the infrared intensity stored in the storage unit 15a as the background while the driving is stopped.
Therefore, for example, when the leak point detector 10 is slowly moved along the inspection target member and the leak point search operation is performed, if the leak gas is detected, the leak point detector 10 moves at and near this detection position. By continuing, the leak point can be detected efficiently. When the distance from the leak point at the tip of the leak point search gas pipe 11 increases and the amount of test gas suction decreases, the test gas concentration in the cuvette 12a decreases and the output of the notification information from the notification unit 16 stops. Therefore, it can be seen that the distance from the leak point at the tip of the leak point search gas pipe 11 is increased. The position of the leak point can be grasped within a range where the output of the notification information from the notification unit 16 continues. Thereby, even a minute leak point with a small leak amount can be detected efficiently.
Similarly, when the leak point search gas pipe 11 is inserted into the space in the inspection target device 2 and the leak point search operation is performed, the leak point can be detected efficiently.

  Needless to say, the leak point detector 10 can be used not only to detect a minute leak point having a leak amount of about several g / year, but also to detect a leak point having a larger leak amount.

In addition, the leak point detector 10 requires only one leak point search gas pipe 11 as a pipe for sucking gas from around the inspection target member 1 and introducing it into the cuvette 12a of the infrared gas analyzer 12. Since a solenoid valve for switching the connection with a plurality of pipes is unnecessary, the cost can be reduced.
Furthermore, the pump 13 can be operated half as compared with the case of a configuration in which suction is alternately performed from two pipes as in the prior art (Patent Document 1), so that the life of the pump 13 can be extended. Further, it is possible to extend the life of the battery power source for driving the pump 13 and to reduce the size thereof. Even when a small and light battery power source is used, a sufficient operating time can be secured, and a leak point detector excellent in portability can be obtained.

(Another aspect: second example of portable leak point detector)
In the above-described embodiment, as an example (first example) when configured to be portable, an infrared gas analyzer 12, a pump 13, and an exhaust pipe in which the pump 13 is connected to a moving operation unit 22 that can be manually moved. However, the present invention is not limited to this. For example, the detector main body 21 includes a drive power supply circuit 131 for driving the pump 13, a battery power supply 133, and the control unit 18. Like the leak point detector 10B (second example of the portable leak point detector) shown in FIG. 7, the infrared gas analyzer 12 and the exhaust pipe 17 may be incorporated in the detector main body. The leak point detector 10B described here includes a detector main body 21a and a movement operation unit 22a. In addition, the same code | symbol is attached | subjected to the same component as the 1st example of a portable leak point detector.

In this leak point detector 10B, the detector body 21a has a drive power supply circuit 131 for driving the pump 13, a battery power supply 133, a control unit 18, an infrared gas analyzer 12, a pump 13, and an exhaust pipe 17 incorporated in a housing. It is.
As shown in FIGS. 6 and 7, the moving operation unit 22a of the leak point detector 10B includes a distal end of a gas introduction hose 25 in which the operation unit main body 221 is extended from the infrared gas analyzer 12 of the detector main body 21a. The intake pipe 222 functioning as the leak point search gas pipe 11 of the leak point detector 10 is communicated with the gas introduction hose 25, and the suction force of the pump 13 is connected to the intake pipe 222 by the gas introduction hose 25. It is comprised so that it may act via. For example, as shown in FIG. 8, the tip of the gas introduction hose 25 is attached to the housing 223 of the operation unit main body 221 and communicates with the intake pipe 222 through the housing 223.
However, the connection mode in which the gas introduction hose 25 and the suction pipe 222 are connected in communication with each other is not limited to this, and can be changed as appropriate. It is the same as the first example of the portable leak point detector described above that the gas sucked from the tip of the intake pipe 222 by the suction force of the pump 13 is introduced into the infrared gas analyzer 12.

  In the case of this leak point detector 10B, the movement operation unit 22a can be easily reduced in size and weight. Thereby, the operativity of the movement operation part 22a can be improved, and the work efficiency of the search of a leak point can be improved.

The inventors of the present invention prototyped and tested a leak point detector having the configuration described as the second example of the portable leak point detector described above.
A pump having a suction amount of 200 mL / min was used.
In addition, the pump drive control circuit switches the pump on and off at 1 Hz.
When the leak point search gas pipe 11 was moved at a search moving speed of 1 cm / sec and the detection of the leak point of 1 g / year of Freon gas (R22) was tested, the leak point was detected.
Also, the leakage point of Freon gas (R22) at 1 g / year, 2 g / year, and 3 g / year was detected, and when the output of the infrared light receiving intensity at the light receiver from the infrared analyzer was examined, the output from the infrared analyzer was It was confirmed that a linear relationship was obtained with respect to the leak amount from the leak point.

It is a model figure explaining the structure of the leak point detector of 1 embodiment which concerns on this invention. It is a whole view explaining an example of the leak point detector (1st example of a portable leak point detector) provided with the detector main body which can be carried, and the movement operation part which can be manually moved. It is a figure which shows an example of the connection form of the intake pipe and cuvette in the movement operation part of the leak point detector of FIG. It is an operation | movement chart explaining operation | movement of the leak point detector which concerns on this invention. It is a figure which shows an example of a structure of the comparison detection part of the leak point detector of FIG. It is a model figure explaining the structure of the 2nd example of the portable leak point detector which concerns on this invention. It is a whole view explaining the structure of the 2nd example of the portable leak point detector which concerns on this invention. It is a figure which shows an example of the connection form of the intake pipe and cuvette in the movement operation part of the leak point detector of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Inspection object member, 2 ... Inspection object apparatus, 10, 10A, 10B ... Leak point detector, 11 ... Gas pipe for leak point search, 12 ... Infrared analyzer, 12a ... Cuvette, 12b ... Light emitter, 12c ... Light receiver, DESCRIPTION OF SYMBOLS 13 ... Pump, 131 ... Drive power supply circuit, 132 ... Switch, 133 ... Battery power supply, 14 ... Pump drive control circuit, 15 ... Comparison detection part, 15a ... Memory | storage part, 15b ... Comparison part, 15c ... Output part, 16 ... Notification unit, 17 ... exhaust pipe, 18 ... control unit, 21, 21a ... detector body, 211 ... hanging string, 22, 22a ... moving operation unit, 221 ... operation unit body, 222 ... intake pipe, 23 ... signal line cable 24 ... Connection pipe, 25 ... Tube for gas introduction.

Claims (5)

A leak point detector used in a test for detecting a leakage location of the test gas from the inspection target member by introducing a test gas having infrared activity into the inspection target member which is a sealed container or a flow pipe,
An infrared gas analyzer in which a light emitter and a light receiver are arranged opposite to each other on a cuvette, one leak point search gas pipe communicated with the cuvette of the infrared gas analyzer, and the cuvette from the tip of the leak point search gas pipe A leak point detector comprising: a pump for introducing gas into the pump; and a pump drive control circuit for switching on / off the driving of the pump at a preset cycle.   Further, the infrared intensity received by the receiver of the infrared gas analyzer during driving of the pump is compared with the infrared intensity received by the receiver during the drive stop time immediately before the start of pump driving. The leak point detector according to claim 1, further comprising a comparison detection unit that outputs a test gas detection signal when the infrared intensity during driving is lower than the infrared intensity immediately before the start of driving.   And a notification unit that outputs notification information for notifying that a test gas has been detected based on a drive command output as a test gas detection signal output from the comparison detection unit. Item 3. The leak point detector according to Item 2.   The pump drive by the pump drive control circuit has a pump drive stop time of 0.3 to 0.5 seconds, and is switched on and off at 0.5 to 1 second per cycle. Item 4. The leak point detector according to any one of Items 1 to 3.   The leak point detection according to any one of claims 1 to 4, wherein a distal end portion of the leak point search gas pipe extending from the cuvette is provided in a movable operation portion that can be manually moved. vessel.

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