JP2006326661A - Gas purging device for weld part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas purging tool, which keeps an oxygen concentration low by filling an inert gas in the inner part of a container that is limited to the vicinity of a penetration bead welding part when conducting penetration bead welding of an end plate to the manhole body of a container to seal the container. <P>SOLUTION: An inner space 4 and an container inner space 5 other than a gas purging region are partitioned by opening the umbrella part of the gas purging tool within the manhole body. Ventilation is conducted between the container inner space 5 other than a gas purging region, which space is not charged with the inert gas, and a container outer space 54 through an inner cylinder 11 even after the partitioning, since a vent hole 53 is formed at an umbrella tip cap 18 of the gas purging tool. Thereby, the inner space 4, which is a gas purging region to be charged with the inert gas, does not become a passage for ventilation caused by the pressure difference between both spaces, so that the outflow of the inert gas from the inner space 4 and the inflow of air into the inner space 4, which are caused in the case of ventilation of the inner space 4, are prevented. Thus, the increase in oxygen concentration in the inner space 4 after charging of the inert gas is prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a gas purging device for a welded part that purges the periphery of a welded part facing the inside of the welded structure with an inert gas when welding the welded structure.

  Container manholes used in nuclear power plants and the like generally have a flange structure and are not closed by welding. However, after a trial run, for example, a manhole of a stainless steel container containing a high radiation dose solution in a spent fuel reprocessing facility, the end plate may be welded to the manhole body to close the container.

When closing the manhole, the end plate is welded from the outside to the manhole body, so a gas protection wall (purge dam) is formed in the container and the air is replaced with an inert gas so that the oxygen concentration is less than 1%. Welding is necessary. For this purpose, a jig for back wave welding is used for a container such as an opening (hereinafter referred to as a gamma hole) for inserting a radiation source (gamma ray irradiation device) into the container, for example, when performing a radiation transmission test. It must be possible to insert and retrieve from the final opening.

  The above gas purge jig can function as a purge dam while being able to be inserted and recovered from the outside of the container. For example, there is a pressure difference between the inside and outside of the spent fuel reprocessing facility and the inert gas. Even in an environment where the outflow of air and the inflow of air occur, it is necessary to ensure sufficient gas sealing performance. Furthermore, it must be able to be installed in a place where there is a structure around the end plate to be welded to the manhole body and a sufficient work area cannot be secured.

  As a method without using such a jig, a method of forming a purge dam by sticking water-soluble paper used for pipe welding to the manhole body is conceivable (for example, see Patent Document 1).

  This method is effective for small-diameter pipes, but when applied to a manhole body with a large inner diameter of 500 to 600 mm, it absorbs moisture inside the container and is easy to peel off. It is difficult to obtain wave welding, and a large amount of water-soluble paper is used, which may remain undissolved in the container. In addition, in order to prevent water-soluble paper from deteriorating due to the heat effect of welding and reducing water-solubility, it is necessary to charge and separate the installation location from the weld line. There may be no space for installation.

  On the other hand, the conventional gas purging jig for piping cannot be taken out from the gamma hole (inner diameter 50mm to 80mm) of the manhole end plate, and the manhole body is short, so this should be applied to manhole welding of containers. I can't.

JP-A-9-10933

  An object of the present invention is to maintain the oxygen concentration in the inert gas purge region as low as possible even when there is a pressure difference between inside and outside the container.

  Means for achieving the object of the present invention includes a first region that fills the space with the inert gas by inserting the space into the space formed in the welded structure and expanding the space, and the inert gas. An impermeable sheet that separates into a second region that is not filled; a frame that supports the sheet; an operating means that operates the frame to expand and contract the sheet; and the second region; It is a gas purging device for a welded portion including a ventilation path communicating with a space outside the welded structure and a flow path for supplying the inert gas to the first region.

  According to the present invention, even if each space in which a pressure difference is generated around the region filled with the inert gas during the welding operation is adjacent, the space can be ventilated between the spaces. Intrusion of air into the region filled with gas can be suppressed, and a decrease in the inert gas concentration in the inert gas filling region can be suppressed.

  Examples according to embodiments of the present invention will be described below with reference to the drawings.

  First, Example 1 will be described with reference to FIGS. Like a manhole in a stainless steel container containing a high radiation dose solution in a spent fuel reprocessing facility, the end plate may be welded to the manhole body after the trial run to close the container. This embodiment is an example when the end plate is welded to the manhole body.

  A stainless steel container 1a shown in FIGS. 1 and 2 is a cylindrical container for storing liquid or gas. This container 1a is installed in a room inside the building of the spent fuel reprocessing facility, and the inside of this room is negative with air-conditioning ventilation equipment compared to the outside of the room so that the atmosphere inside the room does not go out of the room. Maintained at pressure. A cylindrical manhole body 1b is provided on the upper side or side surface of the container 1a. The manhole body 1b has a diameter of 300 mm to 600 mm and is made of a stainless steel plate. The manhole body 1b is coupled to the container 1a by welding.

  The opening of the manhole body 1b is closed by the end plate 1c. The end plate 1c is coupled to the manhole body 1b along the welding line 2 by back wave welding. Thus, the manhole is formed by a welded structure between the manhole body 1b and the end plate 1c. The container 1a is also a welded structure.

  In this welding, a partition device (hereinafter referred to as a gas purge jig) in a gas purge region for replacing the air in the manhole inner space 4 with the inert gas 3 in order to weld the welding wire 2 from the outside of the manhole by reverse wave welding. . The end plate 1c has an insertion hole 1d called a gamma hole for inserting the gamma irradiation apparatus into the container. From this insertion hole 1d, the gas purge jig is inserted into the manhole body 1b.

  The gas purge jig will be described below. The gas purging jig is roughly composed of a sliding cylinder portion 6 and an umbrella portion 7 attached to the cylinder portion 6. As shown in FIG. 3, the cylinder portion 6 includes a hollow cylindrical outer cylinder 10 and a hollow cylindrical inner cylinder 11 that is passed through the outer cylinder 10 with a gap from the inner surface of the outer cylinder 10. It has.

  An operation side cylinder guide 12 is fixed to the outer cylinder 10 at the upper part, and an umbrella side cylinder guide 13 is fixed to the lower part with a set screw. The inner cylinder 11 is passed through the operation-side cylinder guide 12 and the tip-side umbrella-side cylinder guide 13 and is slidably supported so that it can slide in the outer cylinder 10 in the vertical direction. Between the operation side cylinder guide 12 and the inner cylinder 11 and the outer cylinder 10, an O-ring 19 is provided as a seal member for maintaining airtightness. A cylinder guide cap 15 is attached to the lower part of the umbrella-side cylinder guide 13 with a set screw 20, and the inert gas 3 flows from the gap between the lower end of the umbrella-side cylinder guide 13 and the inner cylinder 11 to the inner space 5 of the gas purge region outer container. To prevent leakage.

  The outer periphery of the umbrella side cylinder guide 13 has a cylindrical gap between the outer periphery of the umbrella side cylinder guide 13 and the cylinder guide cap 15 as a cylindrical slit. A cylinder guide cover 14 having a large inner diameter is fixed with a set screw 20.

  The operation side cylinder guide 12 is connected to a gas passage 21 in the operation side cylinder guide 12 as an inert gas injection port 26 from a hose from an inert gas pumping facility. The inert gas introduced from the inert gas inlet 26 passes through the gas passage 21 in the operation side cylinder guide 12, passes through the gas passage 22 that is a gap between the operation side cylinder guide 12 and the inner cylinder 11, and then the outer cylinder 10. And a gas passage 23 that is a gap formed between the inner cylinder 11 and the inner cylinder 11.

The inert gas that has passed through the gas passage 23 further passes through the gas passage 24, the horizontal gas passage 25 provided in the umbrella-side cylinder guide 13 through the gap between the umbrella-side cylinder guide 13 and the inner cylinder 11, The cylindrical slit 16 formed between the umbrella-side cylinder guide 13 and the cylinder guide cover 14 can diffuse into the manhole inner space 4.

  In addition, the umbrella-side cylinder guide cap 15 of the umbrella part 7 is provided with a packing 17 in contact with the gas protection sheet 42 when the umbrella part 7 is unfolded and opened at the attachment part. This packing 17 prevents the inert gas ejected from the cylindrical slit 16 from leaking into the gas purge region outer container internal space 5.

  In this manner, the inert gas is guided from the inlet 26 to the ejection cylindrical slit 16 while preventing leakage of the inert gas.

  The umbrella part 7 has the following configuration. That is, as shown in FIGS. 3, 4, and 5, the umbrella portion 7 has an umbrella frame. The umbrella-shaped frame includes a plurality of parent frames 40 arranged in a radial interval of 15 ° and a receiving frame 41. One end side portions of the parent frame 40 and the receiving frame 41 are connected by a rivet roller fixed rivet joint 52 and are connected to each other so as to be vertically rotatable around the joint.

  The other end portion of the parent frame 40 is pivotally attached to the umbrella side cylinder guide cap 15 so as to be vertically rotatable, and the other end portion of the receiving frame 41 is pivotally attached to the umbrella tip cap 18 so as to be vertically rotatable.

  The umbrella tip cap 18 is attached to the inner cylinder 11 so as to cover the lower end of the inner cylinder 11, and is fixed to the lower end portion of the inner cylinder 11 with a set screw. The umbrella tip cap 18 has a vent 53 that communicates with the inside of the inner cylinder 11. From this vent 53, the air in the container inner space 5 outside the gas purge region passes through the inner cylinder 11 as a vent passage and can exit to the container outer space 54 which is the space of the room where the container 1a is installed.

  In such a gas purge jig, the inner cylinder 11 is pushed downward while holding the outer cylinder 10, so that the parent frame 40 and the receiving frame 41 become straight, the umbrella-shaped frame extends, and the seat 42 is folded. As a result, the umbrella portion 7 is closed, and the reduced state shown in FIG. 2 is obtained. On the contrary, when the inner cylinder 11 is pulled upward while holding the outer cylinder 10, the parent frame 40 and the receiving frame 41 are refracted by the rivet joint 50, and the umbrella portion 7 is opened and unfolded as shown in FIG. Become.

  As shown in FIG. 1, the outer cylinder 10 is provided with a stopper 30 that is installed by fitting into the upper end portion of the insertion hole 1d and that positions the gas purge jig. The stopper 30 is fixed to the outer cylinder 10 by turning the fixing lever 31 of the stopper 30 after inserting the gas purge jig into the stopper 30 and the insertion hole 1d in a state where the umbrella portion is reduced to an appropriate position for forming the purge dam. Positioning is possible. The stopper 30 also functions as a fall prevention tool for the gas purge jig.

  FIG. 6 shows the shape of the outer periphery of the gas protection sheet 42. When the umbrella frame is unfolded and the umbrella portion 7 is opened, the gas protection sheet 42 has an outer diameter that is 20 mm to 30 mm larger than the diameter of the smallest circle that encloses the tips of the parent frame 40 and the receiving frame 41. Have That is, when the umbrella part 7 is expanded, the outer diameter of the seat 42 is formed larger than the outer diameter of the umbrella-type frame.

Therefore, as shown in FIG. 4, when the umbrella portion 7 is expanded and enlarged, the roller 51 rotatably fixed to the tip of the umbrella-type frame by the roller fixing rivet joint 52 is attached to the gas protection sheet 42. The outer peripheral side portion (sheet seal portion 43) is pressed against the inner wall (inner surface) of the manhole body 1b, and the gas protection sheet seal portion 43 is bent so that it hangs down and is in close contact with the inner wall of the manhole body 1b. By this close contact, the inert gas is prevented from leaking from the inner space 4 of the manhole which is the first area located above the gas protection sheet 42 to the inner space 5 of the container outside the gas purge area which is the second area. .

  FIG. 7 is an enlarged view showing a state in which the seat seal portion of the gas protection sheet 42 is bent and is in contact with the inner wall surface of the manhole body 1b. As shown in FIG. 6, the sheet seal portion 43 of the gas protection sheet 42 has a notch 44. In the case where the notch 44 is provided in the seat seal portion 43 of the gas protection sheet 42, when the umbrella portion 7 is opened, the gas protection sheet seal portion is formed as shown in FIG. Since the wrinkles 46 approach, a gap 47 is formed between the inner wall of the manhole and the gas protective sheet seal portion.

  This gap 47 serves as a gas leakage path from the manhole internal space 4 to the gas purge region outer container internal space 5, which causes a reduction in gas purge efficiency. The notch 44 shown in FIG. 6 is shown in FIG. 7B because the triangular notch absorbs wrinkles approaching the closing sheet 42 when the sheet seal portion 43 of the gas protection sheet is bent at a right angle. Thus, an effective purge dam can be formed without generating a gap.

  The frames of the cylinder part 6 and the umbrella part 7 are made of aluminum, so that the weight can be reduced and the handling is easy. The gas protection sheet 42 is made of glass fiber cloth with a silicon coating and has excellent heat resistance, and prevents sheet melting due to welding heat.

  Next, the first embodiment will be described from the aspect of operation. When welding the manhole body 1b and the end plate 1c with the weld line 2, the welding groove alignment at the weld line 2 is performed, and then the umbrella portion 7 of the gas purge jig is contracted as shown in FIG. In the state, the insertion hole 1d is inserted into the manhole body 1b to a predetermined position. The predetermined position is that the cylinder guide cover 14 is positioned below the welding line and above the lower end of the manhole body 1b.

In this way, the sheet 42 is positioned below the weld line 2. Therefore, the stopper 30 and the outer cylinder 10 are fixed by operating the fixing lever 31 of the stopper 30 inserted into the upper opening of the insertion hole 1d. As a result, the gas purge jig is positioned. Next, the inner cylinder 11 of the gas purge jig is pulled up to open the umbrella portion 7 (deployed state) to form a purge dam. The stopper 30 is provided with a hole through which a gas vent pipe 33 and an oximeter are passed, and the periphery of the hole is covered with tape to ensure a sealing property.

  Then, for example, argon gas is injected as an inert gas from the inert gas inlet 26 while measuring the oxygen concentration in the internal space 4 of the manhole body with an oxygen concentration meter 32 inserted from the stopper 30 as shown in FIG. The injected argon gas passes from the operation side cylinder guide gas passage 21 through the gas passage 22 by the gap between the operation side cylinder guide and the inner cylinder 11, and further, the cylinder by the gap between the inner cylinder 11 and the outer cylinder 10. It passes through the inner gas passage 23, further passes through the gas passage 24 formed by the gap between the umbrella side cylinder guide 13 and the inner cylinder, further passes through the umbrella side cylinder guide gas passage 25, and further, the cylinder guide cover 14 and the cylinder guide. It passes through the cylindrical slit 16 formed by the gap between the cap and the jet from the lower end of the cylindrical slit 16 into the inner space 4 of the manhole body, and the air in the inner space 4 of the manhole body is replaced with argon gas. .

  Argon has a molecular weight of 40. On the other hand, since the average molecular weight of air is 29, argon heavier than air gradually pushes air upward from the lower part of the inner space 4 of the manhole body, and the pushed-up air is inserted through the stopper 30. The gas is discharged from the degassing pipe 33 communicating between the inside of the hole 1 d and the container outer space 54 to the container outer space 54.

  The flow rate of argon is adjusted so that the oxygen concentration inside the manhole is lower than the prescribed concentration, and the operator performs TIG welding of the welding line 2 from the outside of the manhole. The manhole body 1b and the manhole end plate 1c are welded under conditions adjusted to have a U-shaped groove 70 as shown in FIG. Not only in the first layer of reverse wave welding, but also in the subsequent several layers of welding, welding is performed while replacing the inside of the manhole with argon gas to prevent deterioration of the quality of the weld due to the influence of oxygen from the inside of the manhole welding line. .

  Since the chamber in which the container 1a is installed is maintained at a negative pressure even during the welding, a pressure difference is generated between the pressure in the container inner space 5 outside the gas purge region and the container outer space 54. At this time, the air in the container internal space 5 outside the gas purge region passes through the internal space 4 of the manhole body, which is an inert gas purge region, and tries to move to the space in the container internal space 5 outside the gas purge region. When such air movement occurs, the inert gas 3 purged in the internal space 4 of the manhole body leaks into the adjacent space, and air enters the internal space 4. The gas concentration is about to fall.

  However, in the embodiment of the present invention, when a pressure difference occurs between the gas purge region outer container inner space 5 and the container outer space 54, the container outer space 54 and the gas purge region pass through the vent 53 and the inner cylinder 11. Since air is ventilated between the outer space 5 and the outer space 5 of the outer container, the phenomenon of air flowing between the outer space 54 and the outer space 5 of the gas purge region via the inner space 4 of the manhole body is generated. Can be prevented. Therefore, it is possible to prevent the inert gas 3 purged into the internal space 4 of the manhole body from being entrained by the ventilation and leaking into the adjacent container outer space 54 or the gas purge region outer container internal space 5.

  Furthermore, the pressure in the container internal space 5 outside the gas purge region and the pressure in the container external space 54 are averaged to prevent the inert gas 3 purged in the internal space 4 of the manhole body from leaking into the container internal space 5 outside the gas purge region, An effective purge dam can also be formed by averaging the pressure.

A sheet 42 serving as a gas protection sheet is stretched on the parent frame 40 of the umbrella frame so that the inert gas stagnates in the inner space 4 of the manhole body, and the sheet 42 is sewn to the parent frame 40 with a thread 45. It has been. Thereby, when the umbrella part 7 is developed, a circular purge dam is formed. The sheet 42 is made of a non-breathable material that is flexible and impermeable to inert gas or air.

  Further, even when the temperature of the container outer space 54 rises due to heat generated during welding and the pressure increases, air in the container outer space 54 enters from the hole at the tip of the inner cylinder 11 and passes through the inner cylinder 11. From the vent 53 provided in the umbrella tip cap 18, the gas flows into the container internal space 5 outside the gas purge region, and the action of equalizing the pressure in the container external space 54 and the gas purge region outside container internal space 5 works to make the inert gas effective. Can be kept purged.

  After the layers are stacked and welded until the surplus 72 reaches a predetermined height, the inner cylinder 11 of the gas purge jig is pushed in, the umbrella portion is folded, and the jig is taken out from the insertion hole.

  In this way, by expanding the sheet of the umbrella part of the gas purge jig in the hole body, the periphery of the welded part is maintained in an inert gas filling space filled with inert gas, and is provided on the umbrella tip cap 18 through the inner cylinder 11. The vent 53 reduces the pressure difference between the container internal space 5 outside the gas purge region and the container external space 54, suppresses gas leakage, and maintains a good gas concentration in the inert gas filling space. By keeping the gas concentration good, good back welding can be performed.

  Next, a second embodiment shown in FIGS. 9 and 10 will be described. In the first embodiment described above, the pressure difference between the container outer space 54 and the gas purge region outer container inner space 5 is equalized through the inner cylinder 11 from the vent 53 provided in the umbrella tip cap 18. Example 2 is caused by the pressure fluctuation in the chamber in which the container 1a is installed, the container outer space 54, the inner space 4 of the manhole body 4, and the large pressure fluctuation generated when welding the container inner space 5 outside the gas purge region. In order to prevent a decrease in gas concentration due to outflow of the inert gas 3 purged into the internal space 4 and inflow of air, a pressure equalizing device is attached to the outside of the gas purge jig of the first embodiment.

The pressure equalizing device is fixed to the lower end of the pressure equalizing pipe 55 and a circular pressure equalizing pipe 55 arranged so as to surround the outer periphery of the outer cylinder, and between the seat 42 on the parent frame 40 and the lower end of the pressure equalizing pipe 55. It comprises pressure equalizing pipe packing 56 for sealing. As shown in FIG. 10, the fixing jig 61 is attached to the outer cylinder 10, and the pressure equalizing pipe 55 is fixed to the gas purge jig with the fixing jig 61. Between the lower end surface of the horizontal flange provided at the upper end of the pressure equalizing pipe 55 and the upper end of the insertion hole 1d, the pressure equalizing pipe sealing material 60 prevents the gas from leaking from the portion where the pressure equalizing pipe 55 is attached to the insertion hole 1d. It has been subjected. A hole is formed in a part of the pressure equalizing pipe sealing material 60, and an inert gas injection hose 59, a gas vent pipe 33, and an oxygen concentration meter 32 are passed through the hole.

  A passage through which air can be ventilated between the pressure equalizing pipe 55 and the container outer space 54 as shown by an arrow in FIG. 10 is secured. A seal is provided between the fixing jig 61 other than the passage and the upper end of the pressure equalizing pipe 55.

  The pressure equalizing pipe packing 56 is fixed to the tip of the pressure equalizing pipe 55 with a pressure equalizing pipe packing presser 57. The pressure equalizing pipe packing presser 57 is fixed to the pressure equalizing pipe 55 with a pressure equalizing pipe packing presser screw 58.

When attaching the pressure equalizing device, the portion between the packing 17 of the gas protection sheet 42 attached to the parent frame 40 and the pressure equalizing pipe packing 56 is removed. Further, when the pressure equalizing pipe 55 is attached, the inert gas 3 is not injected from the inert gas inlet 26, but the inert gas injection hose in addition to the gas vent pipe 33 between the pressure equalizing pipe 55 and the gamma hole 1 d. The inert gas 3 can be injected into the internal space 4 of the manhole body by connecting the inert gas cylinder to the inert gas injection hose 59 while passing through the gas. Since the inert gas injection passage is newly secured in this way, the inert gas injection port 26 is removed from the operation side cylinder guide gas passage 21 of the operation side cylinder guide 12, and the operation side cylinder of the operation side cylinder guide 12 is removed. The guide gas passage 21 is open to the container outer space 54. Other configurations are the same as those of the first embodiment.

  In the present embodiment, the sheet 42 is developed in the manhole body 1b in the same manner as in the first embodiment, and the space between the internal space 4 of the manhole body and the internal space 5 outside the gas purge region is partitioned. When the sheet 42 is deployed, the sheet 42 and the pressure equalizing tube packing 56 are pressed against each other, and the space between the sheet 42 and the pressure equalizing tube packing 56 is sealed.

  Thereafter, an inert gas is injected into the inner space 4 of the manhole body through the inert gas injection hose 59, and the air in the inner space 4 of the manhole body is discharged to the container outer space 54 through the gas vent pipe 33. In this way, the atmosphere in the internal space 4 of the manhole body is replaced with the inert gas. While injecting an inert gas into the internal space 4 of the manhole body 1b, the welding line 2 is welded from the outside of the manhole body 1b.

  If there is a pressure difference between the container outer space 54 and the gas purge region outer container inner space 5, the pressure difference causes the container outer space 54 and the gas purge region outer container inner space 5 to pass through the inner cylinder 11 as in the first embodiment. Air movement occurs between them.

  Air movement also occurs in other passages. That is, when the pressure in the container internal space 5 outside the gas purge region is high, air enters the pressure equalizing pipe 55 from the removed portion of the gas protection sheet 42, and from the gap between the fixing jig 61 and the pressure equalizing pipe 55, Exit to space 54. When the pressure in the container outer space 54 is high, air enters the container inner space 5 outside the gas purge region in the reverse flow.

Furthermore, when the pressure in the gas purge region outer space 5 is high, the air that has entered the pressure equalizing pipe 55 from the portion where the gas protection sheet 42 has been removed is placed between the umbrella side cylinder guide 13 and the cylinder guide cover 14. From the formed cylindrical slit 16, the gas is passed through the gas passage 25 in the umbrella-side cylinder guide and is led to the gas passage 24 and the gas passage 23 in the cylinder formed between the outer cylinder 10 and the inner cylinder 11. The air that has passed through the gas passage 23 in the cylinder passes through the gas passage 22 that is the gap between the operation-side cylinder guide 12 and the inner cylinder 11, passes through the gas passage 21 in the operation-side cylinder guide 12, and exits to the container outer space 54. . When the pressure in the container outer space 54 is high, air enters the container inner space 5 outside the gas purge region in the reverse flow.

  In this way, by improving the air permeability of the container outer space 54 and the gas purge region outer container inner space 5, the pressure in the container outer space 54 and the gas purge outer container inner space 5 is equalized, and the inner space 4 of the manhole body 4 Therefore, the concentration of the inert gas 3 purged in the internal space 4 of the manhole body can be kept constant.

  Next, Example 3 shown in FIG. 11 will be described. The third embodiment is an example in which a part of the second embodiment is improved. In the second embodiment described above, the pressure equalizing tube 55 is fixed to the gas purge jig by the fixing jig 61. In the third embodiment, a pressure equalizing tube insertion mounting jig 62 is provided in the fixing jig 61, and a pressure equalizing tube pressing spring 63 is installed inside.

  The pressure equalizing tube insertion mounting jig 62 includes a disc 80 having an opening at the center, a short tube 81 whose upper end is fixed to the opening edge of the disc 80, and a short tube fixed to the lower surface of the disc. 81 and a circular spring case 82 disposed outside 81. Between the short pipe 81 and the spring case 82, a pressure equalizing pipe presser spring 63 is disposed with the spring stroke direction directed in the vertical direction.

  When the pressure equalizing tube insertion mounting jig 62 is inserted into the upper end of the pressure equalizing tube 55 as shown in FIG. 11, the lower end of the pressure equalizing tube holding spring 63 is received by a spring receiver 83 fixed to the outer periphery of the pressure equalizing tube 55. The upper end of the spring 63 is pressed downward by the lower surface of the disk 80. A pressure equalizing pipe sealing material 60 is provided between the upper end of the pressure equalizing pipe 55 and the disc 80 as in the second embodiment. Similar to the second embodiment, the inert gas injection hose 59 and the gas vent pipe 33 are passed through the pressure equalizing pipe seal member 60 from the container outer space 54 to the inner space 4 side of the manhole body.

  In the case of this embodiment, the inner cylinder 11 is lifted upward with respect to the outer cylinder 10 to open the umbrella portion 7 in the manhole body and unfold the seat 42. Thereafter, the fixing jig 61 is pushed down after the inner cylinder 11 is supported so as not to be lowered. Since the pressure equalizing tube insertion mounting jig 62 that pushes down the fixing jig 61 is also pushed down, the pressure equalizing tube pressing spring 63 is compressed. The pressure equalizing tube 55 is pressed downward by the reaction force generated by the compression of the pressure equalizing tube pressing spring 63, and the pressure equalizing tube packing 56 can be strongly pressed against the gas protection sheet 42 attached to the parent frame 40.

The fixing jig 61 clamps the outer cylinder 10 so that the pressing can be maintained, and the fixing jig 61 and the outer cylinder 10 are integrated. At the position where the pressure equalizing tube insertion mounting jig 62 is pushed down, the pressure equalizing tube sealing material 60 is provided between the pressure equalizing tube insertion mounting jig 62 and the upper end of the insertion hole 1d. In the structure of FIG. 11, it seems that there is a gap through which air escapes between the short pipe 81 and the pressure equalizing pipe 55 or between the pressure equalizing pipe 55 and the spring case 82, but actually, the short pipe 81 and the pressure equalizing pipe 55. Is set as a minimum gap that can move in the vertical direction with each other, so that the air in the pressure equalizing pipe 55 can escape to the container outer space 54 as indicated by the arrow in FIG. In this structure, it is difficult to pass through the gap between 81 and the pressure equalizing pipe 55.

  As described above, the pressure equalizing tube pressing spring 63 of the pressure equalizing tube insertion mounting jig 62 strongly presses the pressure equalizing tube packing 56 against the gas protection sheet 42 to improve the sealing performance, so that the inner space 4 of the manhole body is improved. The concentration of the purged inert gas 3 can be kept constant. Other matters are the same as in the second embodiment.

  Next, Example 4 shown in FIG. 12 will be described. The fourth embodiment is an example in which a part of the structure of the second embodiment is improved. The improvements are as follows. That is, with respect to the inner cylinder 11 of the second embodiment, the upper part of the operation side cylinder guide 12 is joined by the inner cylinder connecting part rivet joint 64 in a state where the umbrella part 7 is opened, and is configured to be bent. The bent portions are two as shown in FIG. 12, and can be directed downward so that the end of the inner cylinder makes a U-turn downward.

  In this embodiment, even if the inner cylinder 11 cannot be used as an air ventilation path between the container outer space 54 and the gas purge region outer container inner space 5 because the inner cylinder 11 is bent, the inner cylinder 11 and the outer cylinder 10 and the pressure equalizing pipe 55 are used as the ventilation path, so that the pressure in the container outer space 54 and the gas purge region outer container inner space 5 can be equalized, and the inner space 4 of the manhole body can be externally disposed in the outer space of the container. It is possible to avoid a ventilation path between the space 54 and the container internal space 5 outside the gas purge region.

  In this way, by providing the inner cylinder connecting portion rivet joint 64 in the inner cylinder 11 of the gas purge jig, the inner cylinder 11 of the gas purge jig can be bent stepwise. As described above, the inner cylinder 11 is gradually bent and becomes compact, so that there is a structure 65 around the end plate 1c of the manhole to be welded to the manhole body 1b. The structure allows jigs to be installed. Other matters are the same as in the second embodiment.

  The gas purging jig according to the present invention is used for forming a purge dam for stagnating an inert gas in a space on the back side of the welding when the end plate is welded to the manhole attached to the container and the manhole is closed. .

It is a longitudinal cross-sectional view in a manhole which shows the state which opened and set the umbrella part in the manhole of the container about the gas purge jig based on Example 1 of this invention. It is a longitudinal cross-sectional view in the manhole which shows the state which closed the umbrella part in the manhole of the container about the gas purge jig based on Example 1 of this invention. It is explanatory drawing of the gas purge jig | tool by Example 1 of this invention, (a) A figure is a longitudinal cross-sectional view of a cylinder part, (b) A figure is a principal part expanded sectional view of (a) figure. It is a longitudinal cross-sectional view of the part which the umbrella part front-end | tip of the gas purge jig | tool by Example 1 of this invention contact | connected the manhole inner wall. It is the top view which showed the relationship between the umbrella flame | frame, the gas protection sheet | seat, and the manhole main body in the state which opened and set the umbrella part in the manhole of the container about the gas purge jig based on Example 1 of this invention. It is a top view which shows the gas-protection sheet | seat outer peripheral part shape of the umbrella part of the gas purge jig based on Example 1 of this invention. It is explanatory drawing which shows the state which the gas-protection sheet seal part of the umbrella part of the gas purging jig based on Example 1 of this invention contacted the manhole inner wall, (a) A figure does not attach a notch to a gas-protection sheet (B) The figure shows the case where the notch was given to the sheet | seat for gas protection. In Example 1 of this invention, it is a longitudinal cross-sectional view of the welding part in the welding line of the end plate of a manhole. It is a longitudinal cross-sectional view in a manhole which shows the state which opened the umbrella part and set the gas purge jig based on Example 2 of this invention in the manhole of a container. It is a principal part expanded sectional view of FIG. It is a longitudinal cross-sectional view of the pressure equalization pipe insertion attachment jig part of the gas purge jig based on Example 3 of this invention. It is a longitudinal cross-sectional view in a manhole which shows the state which opened the umbrella part and set the gas purge jig based on Example 4 of this invention in the manhole of a container.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a ... Container, 1b ... Manhole main body, 1c ... Manhole end plate, 1d ... Gamma hole (insertion hole), 2 ... Welding line, 3 ... Inert gas, 4 ... Internal space of manhole main body, 5 ... Inside gas purge area outside container Space, 6 ... Cylinder part, 7 ... Umbrella part, 10 ... Outer cylinder, 11 ... Inner cylinder, 12 ... Operation side cylinder guide, 13 ... Umbrella side cylinder guide, 14 ... Cylinder guide cover, 15 ... Cylinder guide cap, 16 ... Cylindrical slit, 17 ... packing, 18 ... umbrella tip cap, 19 ... O-ring, 20 ... set screw, 21 ... operating side cylinder guide gas passage, 22, 24 ... gas passage, 23 ... gas passage in cylinder, 25 ... umbrella Side cylinder guide gas passage, 26 ... inert gas inlet, 30 ... stopper, 31 ... fixed lever, 32 ... oxygen concentration meter, 33 ... gas vent pipe, 40 ... parent frame, 4 ... receiving frame, 42 ... gas protection sheet, 43 ... gas protection sheet seal part, 44 ... notch, 45 ... thread, 46 ... wrinkle, 47 ... gap, 50 ... frame joint rivet joint, 51 ... roller, 52 ... Roller fixing rivet joint, 53 ... Vent, 54 ... Container outer space, 55 ... Pressure equalizing pipe, 56 ... Pressure equalizing pipe packing, 57 ... Pressure equalizing pipe packing presser, 58 ... Screw for pressure equalizing pipe packing press, 59 ... Inert gas Injection hose, 60 ... pressure equalizing pipe sealing material, 61 ... fixing jig, 62 ... pressure equalizing pipe insertion mounting jig, 63 ... pressure equalizing pipe presser spring, 64 ... inner cylinder joint rivet joint, 65 ... structure, 70 ... U shape Groove, 71 ... back wave, 72 ... surplus,
80 ... disc, 81 ... short tube, 82 ... spring case, 83 ... spring receiver.

Claims (5)

By inserting and expanding in a space formed in the welded structure, the non-ventilation separates the space into a first region filled with an inert gas and a second region not filled with the inert gas. Sex sheet,
A frame that supports the seat;
Operating means for operating the frame to enlarge and reduce the sheet;
An air passage communicating between the second region and a space outside the welded structure;
A gas purging device for a welded portion including a flow path for supplying the inert gas to the first region. In claim 1,
The frame comprises a parent frame and a receiving frame in which parts on one end side are connected to each other so as to freely rotate up and down,
The operating means is combined with an outer cylinder that supports the other end side portion of the parent frame so as to be rotatable up and down, and the other end side portion of the receiving frame is moved up and down in the outer cylinder. An inner cylinder that is rotatably supported,
A gas purging device for a welded portion in which the inside of the inner cylinder serves as the air passage.   2. The gas purging device for a welded portion according to claim 1, wherein the operation means is bent.   2. The gas purging apparatus for a welded portion according to claim 1, further comprising a pressure equalizing pipe that communicates between the second region and a space outside the welded structure on an outer periphery of the operation means. 3. The gas purge device for a welded portion according to claim 2, wherein a gap between the inner cylinder and the outer cylinder is a flow path for the inert gas.

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