LNG storage tank wall plate positioning method using electromagnetic positioning device

Abstract

The application discloses a LNG storage tank wall plate positioning method using an electromagnetic positioning device for positioning, and steps are as follows: 1, determining how many rings the LNG storage tank wall plate comprises and how many wall plate units each ring comprises; 2, setting an electromagnetic positioning device at each vertical welding seam position; 3, hoisting all the wall plate units needing to be welded in place, starting the electromagnetic suction device to adsorb all the wall plate units through corresponding electromagnets; 4, adjusting each telescopic device; 5, spot welding and fixing and then welding the vertical welding seams of all the aligned wall plate units to form a ring; 6, hoisting the wall plate units having completed welding and executing steps 2 to 5 again to form the next ring of wall plate units, and welding the upper end of the next ring of wall plate units and the lower end of the wall plate units above the ring having been hoisted to form a horizontal welding seam until completion. The application can improve the construction efficiency of LNG storage tank wall plate welding and eliminate the safety hazards of the prior art.

Description

Technical Field

[0001] This invention relates to the field of LNG storage tank construction technology, and in particular to a method for positioning LNG storage tank wall panels using an electromagnetic positioning device. Background Technology

[0002] Currently, large LNG cryogenic storage tanks are mainly divided into three types: single-containment tanks, double-containment tanks, and full-containment tanks. Full-containment tanks consist of an inner tank and an outer tank, which together form a complete storage tank. The inner tank is a self-supporting steel tank for storing liquid products, while the outer tank is a self-supporting steel or concrete tank with an arched roof. Since the storage temperature of LNG is -163℃, perlite particles need to be filled in the annular space between the outer tank and the inner tank to keep the LNG in the inner tank cold.

[0003] The cryogenic steel inner tank, cryogenic steel outer tank, and ambient temperature steel outer tank are designed using the allowable stress method. The materials for the cryogenic steel inner tank and cryogenic steel outer tank are austenitic stainless steel or 9% Ni steel. A single-containment tank currently mainly consists of a cryogenic steel inner tank, a bottom insulation layer, a foundation, a foundation heating system, a flexible insulation seal, a suspended ceiling, an ambient temperature steel tank roof, loose insulation filler, an ambient temperature steel outer tank (not suitable for liquefied natural gas), and a retaining wall. A double-containment tank consists of a cryogenic steel inner tank, a cryogenic steel outer tank, prestressed concrete, a bottom insulation layer, a foundation, a foundation heating system, a flexible insulation seal, a suspended ceiling (insulation layer), an ambient temperature steel tank roof, loose insulation filler, and an ambient temperature steel outer tank (not suitable for liquefied natural gas). The full-containment tank consists of a cryogenic steel inner tank, a cryogenic steel outer tank, a bottom insulation layer, a foundation, a foundation heating system, a flexible insulation seal, a suspended ceiling (insulation layer), a normal-temperature steel top, loose insulation filler, a concrete top, and a prestressed concrete outer tank. The membrane tank consists of a cryogenic steel inner tank, a prestressed concrete outer tank, a bottom insulation layer, a foundation, a foundation heating system, a flexible insulation seal, a suspended ceiling (insulation layer), and an inner insulation layer on the concrete outer tank.

[0004] In the existing technology, the domestic standard used for the installation of such large LNG storage tanks is mainly GB / T26978:2021 Design and construction of on-site assembled vertical cylindrical flat-bottomed steel liquefied natural gas storage tanks.

[0005] However, the existing installation method not only consumes a lot of manpower, but also the grinding of the U-shaped clip fixing position will cause large-area damage to the mother board of the wall panel, or even damage the mechanical properties of that part, affecting the use effect.

[0006] Therefore, how to improve the construction efficiency of LNG storage tank wall welding and eliminate the safety hazards of existing technologies has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of the above-mentioned deficiencies of the prior art, the present invention provides a method for positioning LNG tank wall panels using an electromagnetic positioning device, the purpose of which is to improve the construction efficiency of LNG tank wall panel welding and eliminate the safety hazards of the prior art.

[0008] To achieve the above objectives, the present invention discloses a method for positioning LNG tank wall panels using an electromagnetic positioning device, comprising an electromagnetic positioning device installed on the inner or outer side of the wall panel to be welded in the LNG tank; the electromagnetic positioning device includes at least four electromagnetic suction devices.

[0009] Multiple electromagnetic suction devices are mounted on a support, forming a rectangular array with at least two rows in the vertical direction and at least two columns in the horizontal direction;

[0010] Each of the electromagnetic suction devices includes a telescopic device and an electromagnet capable of extending and retracting in the horizontal direction.

[0011] The support includes guide rods corresponding to the number of columns in the rectangular array;

[0012] One end of each of the telescopic devices is connected to the corresponding guide rod in a sliding pair and can be fixed to the corresponding guide rod by fasteners. The other end of each device points horizontally toward the wall panel unit to be welded and is equipped with an electromagnet.

[0013] Each of the electromagnets is controlled by a controller installed on the bracket, and generates a corresponding electromagnetic force to attract the wall panel unit at the corresponding position according to the electrical energy output by the controller.

[0014] The welding steps are as follows:

[0015] Step 1: Based on the design requirements of the LNG storage tank, determine the number of rings that the wall panel of the LNG storage tank includes from top to bottom, and how many wall panel units each ring includes;

[0016] Step 2: The electromagnetic positioning device is installed at the vertical weld position between every two adjacent wall panel units of each ring;

[0017] The middle position between two or more guide rods of each electromagnetic positioning device is aligned with the corresponding vertical weld, so that all the electromagnetic suction devices located on both sides of the vertical weld correspond to two corresponding wall panel units.

[0018] Step 3: Hoist all the wall panel units that need to be welded into place, and set up U-shaped channel steel fixing expansion rings. Turn on the electromagnetic suction device to attract all the wall panel units through the corresponding electromagnets.

[0019] Step 4: Adjust each of the aforementioned telescopic devices so that all the wall panel units are aligned with the two sides of the outer and inner side walls of the LNG storage tank to meet the design requirements;

[0020] Step 5: Spot weld and fix. Then weld the vertical welds of all the aligned wall panel units to form a ring, and remove the U-shaped channel steel fixing expansion ring.

[0021] Step 6: Lift up the wall panel unit that has been welded, and repeat steps 2 to 5 to form the next ring of the wall panel unit. Weld the upper end of the next ring of the wall panel unit to the lower end of the wall panel unit that has been lifted up to form a transverse weld, until the wall panel welding is completed.

[0022] Preferably, the steps for welding the transverse weld are as follows:

[0023] Step 6.1: Adjust the position of all the electromagnetic suction devices on the corresponding guide rods, so that each electromagnetic suction device near the upper end of the corresponding guide rod is located above the transverse weld, and each electromagnetic suction device near the lower end of the corresponding guide rod is located below the transverse weld.

[0024] Step 6.2: Activate the electromagnetic suction device to attract the corresponding wall panel unit using the corresponding electromagnet;

[0025] Step 6.3: Adjust each of the aforementioned telescopic devices so that the two rings of the wall panel unit are aligned with the two sides of the outer and inner side walls of the LNG storage tank to meet the design requirements;

[0026] Step 6.4: Spot weld to fix and then weld the transverse welds on the already aligned portions of each pair of rings;

[0027] Step 6.5: Adjust the position of each electromagnetic positioning device around the transverse weld to the next welding position of the transverse weld, and repeat steps 6.2 to 6.4 until the welding of the corresponding transverse weld is completed.

[0028] Preferably, each pair of electromagnetic suction devices that are adjacent to each other and correspond to the same row of the rectangular array are provided with a horizontal connecting rod parallel to the horizontal direction, and are fixedly connected by the corresponding horizontal connecting rod.

[0029] Preferably, the telescopic device is an electric telescopic rod with graduations.

[0030] Preferably, each of the telescopic devices has a hole at one end connected to the corresponding guide rod that is in clearance fit with the corresponding guide rod, and the hole wall of the corresponding hole is provided with a set screw as a fastener.

[0031] Preferably, the lower end of the bracket is disposed on a circular track;

[0032] The annular track is arranged around the outer or inner wall of the LNG storage tank, and an unlockable locking device is provided between it and the support.

[0033] The beneficial effects of this invention are:

[0034] The application of this invention can improve the construction efficiency of LNG storage tank wall welding and eliminate the safety hazards of existing technologies.

[0035] Compared with existing technologies, this invention does not require welding many U-shaped fasteners, nor does it require cutting and grinding after welding. This can save a lot of labor costs, shorten the construction period, and reduce damage to the main body of the wall panel of large LNG storage tanks. For example, when the grinding depth of the main body of the wall panel of a large LNG storage tank reaches a certain value, it will cause the wall panel to become unusable.

[0036] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0037] Figure 1 A schematic diagram of the construction state according to an embodiment of the present invention is shown.

[0038] Figure 2 A schematic diagram of the electromagnetic positioning device in one embodiment of the present invention is shown.

[0039] Figure 3 A schematic diagram of the electromagnetic suction device in one embodiment of the present invention is shown. Detailed Implementation

[0040] Example

[0041] like Figures 1 to 3 As shown, an LNG tank wall panel positioning method using an electromagnetic positioning device is described; it includes an electromagnetic positioning device 8 installed on the inner or outer side of the wall panel to be welded in the LNG tank; the electromagnetic positioning device 8 includes at least four electromagnetic suction devices 1.

[0042] Multiple electromagnetic suction devices 1 are mounted on the bracket 9, forming a rectangular array with at least 2 rows in the vertical direction and at least 2 columns in the horizontal direction;

[0043] Each electromagnetic suction device 1 includes a telescopic device 2 capable of extending and retracting in the horizontal direction and an electromagnet 3.

[0044] The support 9 includes guide rods 4 corresponding to the number of columns in the rectangular array;

[0045] One end of each telescopic device 2 is connected to the corresponding guide rod 4 in a sliding pair and can be fixed to the corresponding guide rod 4 by fasteners 5. The other end points horizontally toward the wall panel unit 7 that needs to be welded and is equipped with an electromagnet 3.

[0046] Each electromagnet 3 is controlled by a controller 6 installed on the bracket 9. The controller 6 generates a corresponding electromagnetic force to attract the wall panel unit 7 at the corresponding position based on the electrical energy output by the controller 6.

[0047] The welding steps are as follows:

[0048] Step 1: Based on the design requirements of the LNG storage tank, determine the number of rings that the LNG storage tank wall panels include from top to bottom, and how many wall panel units are included in each ring;

[0049] Step 2: An electromagnetic positioning device 8 is installed at the vertical weld 10 position between every two adjacent wall panel units 7 in each ring.

[0050] Align the middle position between the two or more guide rods 4 of each electromagnetic positioning device 8 with the corresponding vertical weld 10, so that all electromagnetic suction devices 1 located on both sides of the vertical weld 10 correspond to two corresponding wall panel units 7 respectively.

[0051] Step 3: Hoist all wall panel units 7 that need to be welded into place, and set up U-shaped channel steel fixing expansion rings 12. Turn on the electromagnetic suction device 1 to attract all wall panel units 7 through the corresponding electromagnets 3.

[0052] Step 4: Adjust each telescopic device 2 to align the two sides of the outer and inner walls of all wall panel units 7 with the LNG storage tank to meet the design requirements.

[0053] Step 5: Spot weld and fix. Then weld the vertical welds 10 of all the aligned wall panel units 7 to form a ring, and remove the U-shaped channel steel fixing expansion ring 12.

[0054] Step 6: Lift up the wall panel unit 7 that has been welded, and repeat steps 2 to 5 to form the next ring of wall panel unit 7. Weld the upper end of the next ring of wall panel unit 7 to the lower end of the wall panel unit 7 that has been lifted up to form a transverse weld 11 until the wall panel welding is completed.

[0055] In some embodiments, the steps for welding the transverse weld 11 are as follows:

[0056] Step 6.1: Adjust the position of all electromagnetic suction devices 1 on the corresponding guide rods 4 so that each electromagnetic suction device 1 near the upper end of the corresponding guide rod 4 is located above the transverse weld 11, and each electromagnetic suction device 1 near the lower end of the corresponding guide rod 4 is located below the transverse weld 11.

[0057] Step 6.2: Activate the electromagnetic suction device 1 to attract the corresponding wall panel unit 7 through the corresponding electromagnet 3;

[0058] Step 6.3: Adjust each telescopic device 2 so that the two sides of the outer and inner side walls of the two ring wall units 7 are aligned with the design requirements.

[0059] Step 6.4: Spot weld to fix and then weld the transverse weld 11 of the already aligned parts of each pair of rings;

[0060] Step 6.5: Adjust the position of each electromagnetic positioning device 8 around the transverse weld 11 to the next welding position of the transverse weld 11, and repeat steps 6.2 to 6.4 until the welding of the corresponding transverse weld 11 is completed.

[0061] In some embodiments, each pair of electromagnetic suction devices 1 that are adjacent and in the same row of the corresponding rectangular array is provided with a horizontal connecting rod parallel to the horizontal direction, and they are all fixedly connected by the corresponding horizontal connecting rod.

[0062] In some embodiments, the telescopic device 2 is a graduated electric telescopic rod.

[0063] In some embodiments, each telescopic device 2 is provided with a hole at one end connected to the corresponding guide rod 4, which is matched with the corresponding guide rod 4 in a clearance fit, and the hole wall of the corresponding hole is provided with a set screw as a fastener 5.

[0064] In some embodiments, the lower end of the bracket 9 is disposed on a circular track;

[0065] A circular track is installed around the outer or inner wall of the LNG storage tank, and an unlockable locking device is provided between the track and the support 9.

[0066] The distance between the circular track and the outer or inner wall of the LNG storage tank is equal at every point.

[0067] In practical applications, the bottom of the support 9 of the electromagnetic positioning device 8 can be equipped with a wheeled support leg that allows for telescopic height adjustment. The support leg is made of 20# steel. The electromagnetic positioning device 8 is then moved to the vertical weld 10.

[0068] Typically, the electromagnetic positioning device 8 includes four electromagnetic suction devices 1, each with a suction force of 5KN. The positions of the four electromagnetic suction devices 1 are adjusted to always maintain a balanced state.

[0069] The magnitude of the current is controlled by the controller 6, i.e., the switch control box, which controls the current to control the suction force of the electromagnetic suction device 1 to adsorb each wall panel unit 7. Then, the already adsorbed wall panel unit 7 is adjusted to the design requirements by adjusting the telescopic device 2.

[0070] After all the vertical welds 10 are completed, move the electromagnetic suction device 1 to fix the transverse welds 11 between each pair of ring wall panel units 7.

[0071] Among them, the specifications of the U-shaped channel steel fixing expansion ring 12 are: material 20#B, 200*75*9.0mm;

[0072] When welding vertical weld 10, symmetrical welding shall be performed, including root pass, fill pass, and cover pass; the welding rod shall be ASME / AWS SFA / A5.11 ENiCrMo-6.

[0073] When welding transverse weld 11, symmetrical welding shall be performed, including root pass, fill pass, and cover pass; the welding rod shall be ASME / AWS SFA / A5.11 ENiCrMo-6.

[0074] After welding is completed, the vertical weld 10 and the horizontal weld 11 need to be subjected to visual and internal non-destructive testing, including visual inspection for porosity, cracks, etc., and non-destructive testing for radiographic testing and ultrasonic testing.

[0075] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for positioning LNG tank wall panels using an electromagnetic positioning device; characterized in that, Includes an electromagnetic positioning device (8) installed on the inner or outer side of the wall panel to be welded in the LNG storage tank; the electromagnetic positioning device (8) includes at least four electromagnetic suction devices (1); Multiple electromagnetic suction devices (1) are mounted on the bracket (9) to form a rectangular array with at least 2 rows in the vertical direction and at least 2 columns in the horizontal direction; Each of the electromagnetic suction devices (1) includes a telescopic device (2) capable of telescopic extension and retraction in the horizontal direction and an electromagnet (3). The support (9) includes guide rods (4) corresponding to the number of columns of the rectangular array; the lower end of the support (9) is set on a ring track; the ring track is arranged around the outer or inner wall of the LNG storage tank; One end of each of the telescopic devices (2) is connected to the corresponding guide rod (4) in a sliding pair and can be fixed to the corresponding guide rod (4) by fasteners (5). The other end of each device points horizontally to the wall panel unit (7) to be welded to the wall panel and is equipped with the electromagnet (3). Each of the electromagnets (3) is controlled by a controller (6) provided on the bracket (9), and generates a corresponding electromagnetic force to attract the wall panel unit (7) at the corresponding position according to the electrical energy output by the controller (6). The welding steps are as follows: Step 1: According to the design requirements of the LNG storage tank, determine the number of rings of the wall panel of the LNG storage tank from top to bottom, and how many wall panel units are included in each ring (7). Step 2: The electromagnetic positioning device (8) is installed at the vertical weld (10) position between every two adjacent wall panel units (7) of each ring. Align the midpoint between two or more guide rods (4) of each electromagnetic positioning device (8) with the corresponding vertical weld (10), so that all electromagnetic suction devices (1) located on both sides of the vertical weld (10) correspond to two corresponding wall panel units (7). Step 3: Hoist all the wall panel units (7) that need to be welded into place, and set up U-shaped channel steel fixing expansion rings (12). Turn on the electromagnetic suction device (1) to attract all the wall panel units (7) through the corresponding electromagnets (3). Step 4: Adjust each of the telescopic devices (2) so that all the wall panel units (7) are aligned with the two sides of the outer and inner walls of the LNG storage tank to meet the design requirements; Step 5: Spot weld and fix. Then weld the vertical welds (10) of all the aligned wall panel units (7) to form a ring, and remove the U-shaped channel steel fixing expansion ring (12). Step 6: Lift up the wall panel unit (7) that has been welded, and repeat steps 2 to 5 to form the next ring of the wall panel unit (7). Weld the upper end of the next ring of the wall panel unit (7) to the lower end of the wall panel unit (7) that has been lifted up to form a transverse weld (11) until the wall panel welding is completed. The steps for welding the transverse weld (11) are as follows: Step 6.1: Adjust the position of all the electromagnetic suction devices (1) on the corresponding guide rods (4) so ​​that each electromagnetic suction device (1) near the upper end of the corresponding guide rod (4) is located above the transverse weld (11) and each electromagnetic suction device (1) near the lower end of the corresponding guide rod (4) is located below the transverse weld (11). Step 6.2: Turn on the electromagnetic suction device (1) and use the corresponding electromagnet (3) to attract the corresponding wall panel unit (7). Step 6.3: Adjust each of the telescopic devices (2) so that the two rings of the wall panel unit (7) are aligned with the two sides of the outer side wall and the inner side wall of the LNG storage tank to meet the design requirements; Step 6.4, Spot weld to fix and then weld the transverse weld (11) of each pair of rings that have been aligned; Step 6.5: Adjust the position of each electromagnetic positioning device (8) around the transverse weld (11) to the next welding position of the transverse weld (11), and repeat steps 6.2 to 6.4 until the welding of the corresponding transverse weld (11) is completed.

2. The LNG tank wall positioning method using an electromagnetic positioning device according to claim 1, characterized in that, Each pair of electromagnetic suction devices (1) in the same row of the rectangular array is provided with a horizontal connecting rod parallel to the horizontal direction, and they are all fixedly connected by the corresponding horizontal connecting rod.

3. The LNG tank wall positioning method using an electromagnetic positioning device according to claim 1, characterized in that, The telescopic device (2) is an electric telescopic rod with a scale.

4. The LNG tank wall positioning method using an electromagnetic positioning device according to claim 1, characterized in that, Each telescopic device (2) is provided with a hole at one end connected to the corresponding guide rod (4) in a clearance fit with the corresponding guide rod (4), and the hole wall of the corresponding hole is provided with a set screw as the fastener (5).

5. The LNG storage tank wall positioning method using an electromagnetic positioning device according to claim 1, characterized in that, An unlockable locking device is provided between the annular track and the bracket (9).

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