JPH0875587A - Leak detection device of welded part - Google Patents

Abstract

PURPOSE: To obtain a leak detection device for a welded part which can easily detect leakage at a narrow part and at the same time improve the detection accuracy of leakage. CONSTITUTION: The device is provided with a sealing case 13 which is formed in a dish shape and has a flange surface around an opening, a case press means 20 for forming a compartment between a member to be welded and the sealing case 13 by pressing the flange surface of the sealing case 13 to the reverse side of the welding bead of the member to be welded, a gas cylinder 15 as a means for sealing a gas with a specific pressure into the compartment, and a gas detection probe 16 as a means for detecting gas which is provided while opposing the welding bead.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welded portion for detecting a leak in a welded portion arranged in a narrow space, such as an interphase flange portion of a three-phase split field assembly transformer, by an intermediate construction method. The present invention relates to a leak detection device.

[0002]

2. Description of the Related Art FIG. 6 shows, for example, JP-A-57-194328.
It is sectional drawing which shows the conventional leak detection method of the welding part shown by the gazette. In the figure, 1 is an object to be inspected by butt welding, 2 is a welded part of the object to be inspected 1 to be subjected to a leak test,
3 is a bromine phenol as a reagent for ammonia gas detection, which is applied to the surface 1a side of the inspection object 1 so as to cover the welded portion 2, 4a and 4b are separated along the welded portion 2 by a predetermined interval. The adhesive tape is adhered to the surface 1b side of the DUT 1.

Reference numerals 5a and 5b are double-sided tapes having adhesiveness on both sides, which are adhered on both adhesive tapes 4a and 4b, and 6 is affixed at both ends across these double-sided tapes 5a and 5b to cover the welded portion 2. A belt-shaped flexible sheet, 7a and 7b are adhesive tapes attached so as to press both ends of the flexible sheet 6, and 8 is formed between the back surface 1b of the inspection object 1 and the flexible sheet 6. The passage is connected to a gas supply means (not shown) for supplying ammonia gas as a leak test fluid.

Next, the test method will be described. First, ammonia gas is supplied from the gas supply means into the passage 8 formed by the flexible sheet 6 to fill the passage 8 under pressure. At this time, if there is a defect in the welded portion 2, since bromphenol 3 is applied to the surface 1a side, ammonia in the passage 8 leaks through the defective portion, and bromphenol 3 is introduced.
It dissolves in and shows a characteristic color reaction of purple blue. Ammonia gas leak is detected by this color reaction, and a defect in the weld 2 is detected.

[0005]

As described above, the conventional leak detection of a welded portion requires a work such as attaching a flexible sheet to the welded portion with an adhesive tape or applying a reagent, which is narrow. It is very difficult to detect leaks at various locations, and since both ends of the flexible sheet that forms the ammonia gas passage for leak tests are sealed with adhesive tape,
Since it is difficult to fill the gas with a high pressure, the detection accuracy becomes low, and further, there is a problem that even in the visual inspection, the eyes cannot be seen by a person and only the inspection can be performed with a mirror or the like.

The present invention has been made in order to solve the above problems, and facilitates the detection of leaks in narrow spaces, and enables the application of high-pressure leak test gas to detect leaks. It is possible to improve accuracy,
Further, an object of the present invention is to obtain a leak detecting device for a welded portion, which can prevent the influence on the surroundings even if the leak of the leak test gas occurs, and can easily perform the appearance inspection. Is.

[0007]

According to a first aspect of the present invention, there is provided a leak detecting device for a welded portion, which is a dish-shaped case and has a flange surface around the opening, and a flange surface of the case. Case pressing means for pressing the back side of the welding bead of the member to form a compartment between the member to be welded and the enclosing case, gas enclosing means for enclosing a gas of a predetermined pressure in the compartment, and a welding bead And a gas detecting means arranged so as to face each other.

According to a second aspect of the present invention, there is provided a leak detecting device for a welded portion, which includes a sealing case formed in a dish shape and having a flange surface around the opening, and a flange surface of the sealing case having a welding bead of a member to be welded. Case pressing means for forming a compartment between the member to be welded and the encapsulation case by pressing to the back side of the, a gas enclosing means for enclosing a gas of a predetermined pressure in the compartment, and a welding bead facing each other. And a shape detecting means for detecting the shape of the welding bead.

Further, according to a third aspect of the present invention, there is provided a leak detecting device for a welded portion according to the first or second aspect, wherein an annular groove is formed on the flange surface of the enclosing case along the flange surface and the inside of the groove is vacuumed. It is made pullable.

According to a fourth aspect of the present invention, there is provided the leak detecting device for a welded portion according to any one of the first to third aspects, wherein the enclosure case is formed of a hard elastic member.

A leak detecting device for a welded part according to a fifth aspect of the present invention is the device according to the first or second aspect, wherein the gas detecting means and the shape detecting means run along the welding bead.

The weld leak detecting device according to claim 6 of the present invention is applied to the weld between the interphase flanges of the three-phase split field assembly transformer according to any one of claims 1 to 5. is there.

[0013]

In the leak detecting device for the welded portion according to the first aspect of the present invention, the flange surface is pressed by the case pressing means to the back side of the weld bead of the member to be welded.
The gas sealing means seals high-pressure gas, and the gas detecting means detects gas leaking from the weld.

Further, in the leak detecting device for the welded portion according to the second aspect of the present invention, a high pressure is provided by the gas enclosing means in the enclosing case whose flange surface is pressed by the case pressing means to the back side of the weld bead of the member to be welded. While enclosing the gas, the gas detecting means detects the gas leaking from the welded portion, and the shape detecting means detects the external shape of the welding bead.

Further, in the leak detecting device for the welded portion according to the third aspect of the present invention, the gas leaking from the inside of the enclosing case is captured in the annular groove formed on the flange surface of the enclosing case, and is collected by vacuuming. To do.

Further, in the leak detecting device for a welded portion according to claim 4 of the present invention, since the enclosing case is formed of a hard elastic member, the back side of the welded member is hermetically sealed without interposing a seal member. Pressed.

Further, in the leak detecting device for a welded portion according to the fifth aspect of the present invention, the gas detecting means and the shape detecting means are caused to travel along the welding bead to increase the leak detecting speed to improve work efficiency. .

The leak detecting device for welds according to claim 6 of the present invention detects leaks in the weld between the interphase flanges of the three-phase split field assembly transformer.

[0019]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings by applying it to a welded portion between interphase flanges of a three-phase split field assembly transformer. 1 is a diagram showing a schematic configuration of a leak detection device for a welded portion in Embodiment 1 of the present invention, FIG. 2 is a diagram showing a configuration of a welded portion between interphase flanges of a three-phase split field assembly transformer shown in FIG. 1, 3 is a front view showing the structure of the case pressing means shown in FIG. 1, FIG. 4 is a plan view showing the details of the enclosed case shown in FIG. 1, a front view and a side view, and FIG. 5 is a diagram showing the enclosed case shown in FIG. It is sectional drawing which shows the state pressed on the welding bead back surface side of a welding member.

Generally, as shown in FIG. 2, a three-phase split field assembly transformer has windings (not shown) for each phase and each middle tank 9 for each phase.
a, 9b, 9c and lower tanks 10a, 10b, 10
After being stored in c and transported to the site, the interphase flanges 11a, 11b, 11c fixed to the upper parts of the respective lower tanks 10a, 10b, 10c are welded and integrated at each site, and then each tank 9a, 9b, 9c, 10a, 10
Field assembly is completed by removing b and 10c, mounting and combining iron cores between the windings, storing them in this tank (not shown), and enclosing the insulating medium.

Therefore, the interphase flanges 11a, 11
Airtightness is required for each of the welded portions 12a and 12b formed by welding between b and 11c. However, once the welding portion 12a, after being stored in the main tank,
When a leak is detected in 12b, the repair work becomes very difficult. Therefore, as shown in FIG.
Immediately after welding between 11b and 11c, leak detection of the welded portions 12a, 12b, and 12c is performed under conditions where the work is extremely narrow and difficult to work.

In the figure, reference numeral 13 designates a dish-shaped enclosure case, and a flange surface 13a is formed around the upper opening as shown in FIG. 4, and an exhaust port 13b is formed along this flange surface 13a. An annular groove 13c is provided, and a gas inlet 13d is provided at the bottom. Reference numeral 14 is a vacuum pump connected to the exhaust port 13b via a valve 14a, and 15 is a dual valve 1 connected to the gas charging port 13d.
It is a gas cylinder as a gas sealing means connected via 5a and 15b.

Reference numeral 16 is a gas detection probe as a gas detection means which is arranged above the welding bead of the welded portion 12a so as to be opposed thereto, and is connected to the gas detector 17. Reference numeral 18 is a visual sensor as shape detecting means, which is arranged above the welding bead of the welded portion 12a so as to face the same as the gas detection probe 16, and is connected to the video monitor 19. Then, these gas detection probe 16 and visual sensor 18
Is held by an automatic traveling device (not shown) and is arranged so as to be able to travel along the welding bead.

Reference numeral 20 denotes a case pressing means for holding the enclosed case 13 and pressing it against the back side of the welding beads of the interphase flanges 11a and 11b through the packing 26 as shown in FIG. 5, and as shown in FIG. A plurality of hydraulic cylinders 22 are mounted on the upper side, and a guide roller 23 for guiding the case pressing means 20 with the side surfaces of the lower tanks 10a, 10b as guides on the side surfaces of the frame 21 is provided between the lower tanks 10a, 10b. Further, moving rollers 24 for facilitating the movement of the case pressing means 20 are provided on the lower surface of the frame 21. Reference numeral 25 is a hydraulic unit that is connected to each hydraulic cylinder 22 and supplies a predetermined drive pressure, and 27 is a compartment formed between the interphase flanges 11a and 11b and the enclosure case 13.

Next, the operation of the leak detecting device for the welded portion constructed as described above will be described. First, the case pressing means 20 is inserted between the lower tanks 10a and 10b via the guide roller 23 and the moving roller 24, and
Above the welded portion 12a of the interphase flanges 11a and 11b,
An automatic traveling device (not shown) so that the gas detection probe 16 and the visual sensor 18 face the welding bead, respectively.
Attach. Next, the hydraulic unit 25 is driven to supply a driving pressure to each hydraulic cylinder 22, so that the sealed case 1
3 is pressed against the back surface side of the welded portion 12a of the interphase flanges 11a and 11b through a packing 26 to form a compartment 27.

The gas cylinder 1 is placed in the compartment 27.
After supplying gas from 5 through the gas charging port 13d and maintaining the inside of the compartment 27 at a predetermined pressure, an automatic traveling device (not shown) is moved along the welding bead at a speed of 2 to 3 cm / sec. The gas detection probe 16 and the visual sensor 1
8, the shapes of the gas leaking from the welded portion 12a and the welding bead are monitored, and if there is a gas leak or an abnormal shape, the gas detector 17 and the video monitor 19 detect it. On the other hand, when the gas sealed in the compartment 27 leaks from the packing 26, the gas is captured in the annular groove formed around and is vacuumed by the vacuum pump 14 to be collected.

As described above, according to the first embodiment, the structure as described above facilitates detection of leaks in a narrow space, and the use of the enclosed case 13 enables application of high-pressure gas. Therefore, it is possible to improve the detection accuracy of the leak, and by monitoring the shape of the welding bead by the visual sensor 18, it is possible to predict a location where there is a risk of leak, and to further improve the detection accuracy. Can be improved, and the enclosing case 13
By forming the annular groove 13c on the flange surface 13a of the above and vacuuming the same, it is possible to prevent adverse effects such as gas leaking from the inside of the compartment 27 to the outside and adversely affecting it. Moreover, automatic traveling is also possible. By moving the gas detection probe 16 and the visual sensor 18 by the device, the leak detection speed can be increased and the work efficiency can be improved.

Embodiment 2 FIG. In the first embodiment, the airtightness is maintained by interposing the packing 26 between the enclosing case 13 and the interphase flanges 11a and 11b. However, the enclosing case 13 itself is made of a hard elastic member. If formed, it becomes possible to maintain sufficient airtightness without interposing packing 26 or the like.

Example 3. Further, in each of the above-described embodiments, the case where the invention is applied to the welding portion between the interphase flanges of the three-phase split field assembly transformer has been described, but the present invention is not limited to this, and the welding bead is arranged in a narrow place. It is needless to say that it can be applied as long as it has a welded part and the same effects as those of the above-mentioned respective examples can be exhibited.

[0030]

As described above, according to the first aspect of the present invention, the encapsulating case formed in the shape of a dish and having the flange surface around the opening, and the flange surface of the encapsulating case of the welding bead of the member to be welded. Case pressing means for pressing the rear surface side to form a compartment between the member to be welded and the enclosing case, gas enclosing means for enclosing a gas of a predetermined pressure in the compartment, and a welding bead arranged opposite to each other. Since it is equipped with gas detection means, it is easy to detect leaks in narrow spaces and
It is possible to provide a leak detection device for a welded portion, which enables high-pressure leak test gas to be applied and improves the accuracy of leak detection.

According to the second aspect of the present invention, the enclosing case formed in a dish shape and having the flange surface around the opening, and the flange surface of the enclosing case are pressed against the back surface side of the welding bead of the member to be welded. Case pressing means for forming a compartment between the member to be welded and the enclosing case, a gas enclosing means for enclosing a gas of a predetermined pressure in the compartment, and a gas detector arranged to face the welding bead, respectively. Since it is equipped with a means and a shape detection means for detecting the shape of the weld bead, it facilitates the detection of leaks in narrow spaces and enables the application of high-pressure leak test gas to improve the accuracy of leak detection. Of course it can be improved,
It is possible to provide a leak detection device for a welded portion that can predict a location where a leak may occur in the future.

Further, according to claim 3 of the present invention, in claim 1 or 2, since the annular groove along the flange surface is formed on the flange surface of the enclosing case and the inside of the groove can be evacuated. In addition to facilitating the detection of leaks in narrow spaces and enabling the use of high-pressure leak test gas, it is possible to improve the accuracy of leak detection, as well as leakage from the enclosed case. It is possible to provide a leak detection device for a welded portion that can capture and recover gas.

According to a fourth aspect of the present invention, in any one of the first to third aspects, since the encapsulating case is formed of a hard elastic member, it is easy to detect a leak in a narrow space, and It is of course possible to improve the detection accuracy of the leak by enabling the application of a high-pressure leak test gas, and also to press airtightly without interposing a seal member on the back side of the welded member. It is possible to provide a leak detection device for a welded part.

Further, according to claim 5 of the present invention, in any one of claims 1 to 3, it is possible to travel along the welding bid, so that it is possible to easily detect a leak in a narrow space, and It is not only possible to improve the accuracy of leak detection by enabling the use of high-pressure leak test gas, but it is also possible to improve the work efficiency by increasing the leak detection speed. The leak detection device can be provided.

Further, according to claim 6 of the present invention, in any one of claims 1 to 5, the invention is applied to the leak detection of the welded portion between the interphase flanges of the three-phase split field assembly transformer, so that it is a narrow place. Leak detection in the
It goes without saying that high-pressure leak test gas can be applied to improve the leak detection accuracy, and leak detection is performed earlier than the pressurization test when assembling the entire transformer. It is possible to provide a leak detection device for a welded part.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a leak detection device for a welded portion according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a welded portion between interphase flanges of the three-phase split field assembly transformer shown in FIG.

FIG. 3 is a front view showing the configuration of the case pressing means shown in FIG.

FIG. 4 shows the details of the enclosing case shown in FIG.
(A) is a plan view, (B) is a front view, and (C) is a side view.

5 is a cross-sectional view showing a state in which the enclosure case shown in FIG. 4 is pressed against the back surface of the weld bead of the member to be welded.

FIG. 6 is a cross-sectional view showing a conventional leak detection method for a welded portion.

[Explanation of symbols]

9a-9c Middle part tank, 10a-10c Lower part tank, 11a-11c Interphase flange, 12a, 12b
Welded part, 13 enclosed case, 14 vacuum pump, 15
Gas cylinder (gas filling means), 16 gas detection probe
(Gas detection means), 18 visual sensor (shape detection means), 2
0 case pressing means, 27 compartments.

Claims (6)

[Claims] 1. An encapsulation case formed in a dish shape and having a flange surface around an opening, and a flange surface of the encapsulation case is pressed against the back surface side of a welding bead of a member to be welded, the member to be welded and the encapsulation case. A case pressing means for forming a compartment between the compartment, a gas enclosing means for enclosing a gas of a predetermined pressure in the compartment, and a gas detecting means arranged to face the welding bead. A leak detection device for welded parts. 2. An encapsulation case formed in a dish shape and having a flange surface around the opening, and a flange surface of the encapsulation case is pressed against the back surface side of the welding bead of the member to be welded, and the member to be welded and the encapsulation case. A case pressing means for forming a compartment between the compartment, a gas enclosing means for enclosing a gas of a predetermined pressure in the compartment, a gas detecting means and a welding bead arranged to face the welding bead, respectively. And a shape detecting means for detecting the shape of the welding part. 3. The leak detection of the welded portion according to claim 1, wherein an annular groove is formed on the flange surface of the enclosure case along the flange surface and the inside of the groove can be evacuated. apparatus. 4. The leak detecting device for a welded portion according to claim 1, wherein the enclosure case is formed of a hard elastic member. 5. The leak detecting device for a welded portion according to claim 1, wherein the gas detecting means and the shape detecting means are configured to run along the welding bead. 6. The welded member is an interphase flange of a three-phase split field assembly transformer.
The leak detection device for a welded part according to any one of 1.