Assembly method for an assembled oil storage tank structure

Abstract

The present invention discloses an assembling method for an assembled oil storage tank structure, including Step 1: foundation construction; Step 2: prefabrication of the oil storage tank; Step 3: assembly of the tank bottom plate; Step 4: installation of auxiliary equipment; Step 5: assembly of the top ring of the tank wall; Step 6: assembly of the tank top; Step 7: assembly of the remaining tank walls; and Step 8: assembly of the bottom layer of the tank wall and the tank bottom plate. The oil storage tank assembled by this method has high installation accuracy, convenient installation accuracy detection, is convenient for adjusting the position and attitude of the installation components, has improved stability, low construction cost, and low repair rate of the welded oil storage tank.

Description

Technical Field

[0001] The present invention relates to the technical field of on-site assembly of metal oil tanks, and particularly relates to an assembly method for an assembled oil storage tank structure. Background Art

[0002] With the expansion of production scale and technological upgrading in various industries, especially in industries such as chemical, food, pharmaceutical, petroleum, and natural gas, the demand for metal tanks has been continuously increasing due to their corrosion resistance, easy cleaning, high strength, etc. Since metal tanks are large in volume and weight, they are usually assembled on-site. The most difficult and labor-intensive steps during on-site assembly are on-site alignment and welding operations, mainly including the alignment of storage tank wall panels, the position adjustment of storage tank wall panels and the bottom plate, and the reservation and setting of shrinkage joints. Currently, on-site installation mainly involves multiple workers cooperating for splicing and welding operations, which requires a high level of coordination and cooperation ability and increases the construction cost. The invention patent with the authorization announcement number CN115106623B discloses a method for assembling the side wall of a large BOP process storage tank, which includes the following steps: 1) Installing a storage tank ring-shaped operation platform vehicle; 2) Enclosing, aligning, and longitudinally welding the first ring of wall panels under the tank top; 3) Installing a storage tank synchronous hydraulic lifting device; 4) Enclosing the second ring of wall panels under the tank top; 5) Integrally lifting the first ring of wall panels under the tank top; 6) Aligning and longitudinally welding the enclosing plates of the second ring of wall panels under the tank top; 7) Welding the circumferential seams of the first and second rings of wall panels under the tank top; 8) Repeating steps 4) - 7) until the overall welding of the storage tank side wall is completed. It effectively reduces the demand for senior welder talents and reduces the workload of construction workers working at heights. While improving the construction efficiency of the storage tank, it ensures the welding quality, and the overall working efficiency is increased to 3 times the existing construction efficiency, accelerating the application of automatic welding technology in the third-generation nuclear power market. However, the ring-shaped operation platform vehicle used in its construction is complex to install and has high requirements for installation accuracy, increasing the construction cost. Summary of the Invention

[0003] The object of the present invention is to provide an assembly method for an assembled oil storage tank structure. The oil storage tank assembled by this method has high installation accuracy, convenient installation accuracy detection, is convenient for adjusting the position and attitude of installation components, has smooth lifting, low construction cost, and low repair rate of the welded oil storage tank.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] An assembly method for an assembled oil storage tank structure, the assembly method includes the following steps:

[0006] Step 1, foundation construction, constructing multiple foundation piles at the bottom of the oil storage tank installation area, laying a perlite concrete cushion layer in this area, and laying an asphalt sand insulation layer on the top of the perlite concrete cushion layer; setting azimuth marks on the asphalt sand insulation layer;

[0007] Step 2: Prefabrication of the storage tank. Divide the tank bottom plate into multiple edge plates and middle web plates; the tank wall is composed of multiple wall plates spliced together. Mark the cutting lines, standard lines, and three-equal-part alignment lines of the plate length on the steel plate, and mark the dimensions and numbers on the wall plates; the tank top plate includes multiple gore plates and stiffeners fixedly arranged on the inner wall of the gore plates. After cutting the gore plates, they are integrally formed using a vault forming jig.

[0008] Step 3: Assembly of the tank bottom plate. First, lay the backing plates on the foundation. After laying the backing plates into a circle, lay the edge plates on the backing plates. When laying, use spacer limit blocks to adjust the interval between adjacent two edge plates. After the overall adjustment is completed, use a gantry clamp for fixation; then lay the middle web plates. The middle web plates are laid one by one from the center of the tank bottom to both ends. After the middle row is laid, based on the middle row, lay row by row to both sides. Each row of middle web plates is laid from the middle to both sides in sequence; after the overall laying of the tank bottom plate is completed, weld the splicing seams of adjacent two middle web plates; the lap weld between the edge plate and the middle web plate is temporarily not welded as a shrinkage joint.

[0009] Step 4: Installation of auxiliary equipment. Install a positioning component at the center position of the tank bottom. The positioning component is used to measure the position and levelness of each wall plate relative to the center of the tank bottom; install a lifting component on the tank bottom and inside the tank wall. The lifting component is used to lift the assembled tank wall; the positioning component includes a support column fixedly installed at the center of the tank bottom plate and a support seat rotatably arranged on the support column. A level and a laser displacement sensor are fixedly installed on the support seat. Two photosensitive elements are horizontally arranged on the inner side of each wall plate. The photosensitive elements are used to receive the optical signals of the level and the laser displacement sensor and convert them into electrical signals.

[0010] Step 5: Assembly of the top ring tank wall. Through the positioning of the positioning component, draw the inner and outer circumferential lines of the top ring tank wall on the tank bottom plate. Along the inner side of the inner circumferential line, arrange several adjustable positioning parts at intervals. Assemble the wall plates according to the number marks and corresponding azimuth marks. When assembling, use the positioning component and a square to detect the position, levelness, and perpendicularity of the wall plate installation. When the perpendicularity, radian, and circumference of the entire ring of the tank wall meet the requirements, spot-weld the vertical seams of adjacent two wall plates, leaving one vertical seam as a vertical shrinkage joint. After the spot welding is completed, perform overall welding of the vertical seams, and finally weld the vertical shrinkage joint; the adjustable positioning part includes an L-shaped support bottom plate fixedly installed on the tank bottom plate and two adjusting bolts adjustably installed on the L-shaped support bottom plate. It also includes an adjusting rod hinged between the wall plate and the tank bottom plate. Adjust the perpendicularity of the wall plate by adjusting the length of the adjusting rod.

[0011] Step 6: Crown assembly. First, assemble two gore plates at the axisymmetric positions, perform tack welding after uniform adjustment, then assemble the other gore plates, and adjust the lap width to 60 mm. After the assembly of the gore plates is completed, perform welding in a backward welding manner, and then weld the intermittent welds on the inner side of the crown and the connecting welds of the rib plates. Finally, weld the angle steel at the skirt and install the accessories of the crown opening machine on the crown.

[0012] Step 7: Assembly of the remaining tank walls. Install an internal expansion ring on the inner side of the top ring of the tank wall. The internal expansion ring is fixedly installed on the inner side of the wall plate by using portal plates. Install the sub-top ring of the tank wall on the outer side of the top ring of the tank wall at the corresponding positions, leaving a live opening. Connect the internal expansion ring with the lifting assembly, lift the top ring of the tank wall above the position where the two rings of the tank wall are to be assembled through the lifting assembly, assemble the sub-top ring of the tank wall in the manner of Step 3. After the welding of the sub-top ring of the tank wall is completed, splice the top ring of the tank wall and the sub-top ring of the tank wall through the lifting assembly, perform spot welding fixation after adjusting their positions and postures, and conduct inspection on the shape and dimensions of the tank wall. After passing the inspection, weld the circumferential weld between the top ring of the tank wall and the sub-top ring of the tank wall. The third and fourth rings of the tank wall from top to bottom are lifted, assembled and installed according to the above operations until the assembly of the bottom layer of the tank wall is completed.

[0013] Step 8: Assembly of the bottom layer of the tank wall and the tank bottom plate. After the installation of the bottom layer of the tank wall is completed, perform the opening, connection pipe and roof installation of the construction tank body. First, perform spot welding on the bottom layer of the tank wall and the tank bottom plate, measure the dimensions and shape of the tank body and then perform full welding. After the welding is completed, weld the shrinkage seams between the edge plates and the middle plates and between the edge plates. After the welding is completed, conduct vacuum inspection.

[0014] Preferably, draw the cutting lines and standard lines of each edge plate and middle plate on the steel plate, and perform number marking on each edge plate and middle plate. One end of the edge plate is arc-shaped, and the dimension of the edge plate along the radius direction of the tank bottom is greater than or equal to 700 mm. The middle plate is rectangular, the width of the middle plate is greater than or equal to 1000 mm, and the length is greater than or equal to 2000 mm.

[0015] Preferably, in Step 3, the middle plate and the edge plate are temporarily welded through a temporary positioning plate to control the welding deformation amount.

[0016] Preferably, in Step 3, before laying the tank bottom plate, an anti-corrosion coating should be applied on the lower surface of the tank bottom plate, and the area within 50 mm from the edge of each tank bottom plate is not coated.

[0017] Preferably, in Step 4, the lifting assembly includes a lifting column fixedly installed on the tank bottom plate and a chain block installed at the top of the lifting column. The hook of the chain block is connected to the wall plate, and the wall plate is lifted through the chain block.

[0018] Preferably, in the fifth step, after the top ring tank wall is assembled and welded, a skirt angle steel is installed at the top of the top ring tank wall. The butt weld of the skirt angle steel is staggered from the vertical seam of the wall plate, and the lap joint between the skirt angle steel and the wall plate is temporarily fixed by spot welding.

[0019] Preferably, in the seventh step, the internal expansion ring is 200 mm away from the lower opening of the top ring tank wall. The internal expansion ring is composed of channel steel in 1 / 4 type and is connected into a whole ring by 15-ton screw jacks.

[0020] Preferably, in the eighth step, for the welding of the large fillet weld between the bottom layer of the tank wall and the tank bottom plate, first weld along the same direction inside and outside the tank simultaneously by using the method of segmental backward welding or skip welding. After welding, 100% magnetic particle or penetrant inspection is carried out. Then, the filling and capping layers are welded in segments along the same direction by four symmetrically distributed angle submerged arc automatic welding machines. During operation, weld the inner side first and then the outer side.

[0021] Preferably, before welding, reinforcement supports shall be carried out inside the bottom layer of the tank wall. The distance between adjacent two reinforcement support points is less than or equal to 1200 mm, and the reinforcement supports shall be removed after the shrinkage seam of the tank bottom is welded.

[0022] In the present invention, by adopting the above steps, the storage oil tank can be welded layer by layer with high precision, effectively reducing the requirements for the operation level of welding workers, avoiding the high-altitude operation of operators, and improving the construction safety. For the laying and welding of the tank bottom plate, first weld the middle web plate, and then weld between the edge plates after the tank wall is welded and welded with the edge plates. And use temporary positioning plates and gantry clamps for fixation, which is convenient for controlling the deformation during welding.

[0023] The set positioning component is used to measure the position and levelness of each wall plate relative to the center of the tank bottom, and cooperate with a square to measure the perpendicularity of the wall plate installation. It can quickly measure each installed wall plate, avoiding the disadvantages of the traditional repeated adjustment of measuring instruments for one measurement, and improving the measurement efficiency and accuracy. The set adjustable positioning part can, on the one hand, position and limit the installation of the wall plate, and on the other hand, can also adjust the position and angle of the wall plate installation. It has two functions in one device, reducing the use of auxiliary adjustment equipment and also reducing the number of adjusting personnel, thus reducing the construction cost.

[0024] During this construction process, the method of synchronous lifting by multiple chain blocks is adopted for lifting. The operation is simple and the cost is low. The number of chain blocks can be adaptively adjusted according to the size of the storage oil tank, and the versatility is good. It avoids the disadvantages of oil leakage and difficult synchronous control during hydraulic lifting, and is also convenient for being carried out of the storage oil tank after disassembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the construction process of the present invention;

[0026] Figure 2 Schematic cross-sectional view of the basic structure of the present invention;

[0027] Figure 3 Top view schematic of the edge plate structure of the present invention;

[0028] Figure 4 Top view schematic of the middle web plate structure of the present invention;

[0029] Figure 5 Top view schematic of the wall plate structure of the present invention;

[0030] Figure 6 Schematic of the laying state of the edge plate of the present invention;

[0031] Figure 7 Schematic of the working state of the positioning component of the present invention;

[0032] Figure 8 Schematic of the lifting state of the lifting component of the present invention;

[0033] Figure 9 Schematic of the structure of the adjustable positioning member of the present invention;

[0034] In the figure: 1, foundation pile; 2, perlite concrete cushion; 3, asphalt sand insulation layer; 4, edge plate; 5, middle web plate; 6, wall plate; 7, backing plate; 8, spacer limit block; 9, gantry clamp; 10, wedge; 11, positioning component; 12, lifting component; 13, adjustable positioning member; 14, square; 110, support column; 111, support base; 112, level; 113, laser displacement sensor; 114, photosensitive element; 120, lifting column; 121, chain block; 130, L-shaped support bottom plate; 131, adjusting bolt; 132, adjusting rod. Specific embodiments

[0035] The present invention will be further described below with reference to the accompanying drawings:

[0036] As Figures 1 to 9 shown, an assembling method for an assembled storage tank structure, the assembling method comprising the following steps:

[0037] Step 1, Foundation construction: Construct multiple foundation piles 1 at the bottom of the storage tank installation area, lay a perlite concrete cushion 2 in this area, lay an asphalt sand insulation layer 3 on the top of the perlite concrete cushion 2, and set orientation marks on the top of the asphalt sand insulation layer 3. The orientation marks include 0°, 90°, 180°, and 270° identifications. When laying the perlite concrete cushion 2, the laying thickness of each layer is 100 mm, and the layered thickness can be controlled by staking. Each layer of the perlite concrete cushion 2 is tamped by vibration, ramming, or compaction. In this embodiment, the thickness of the perlite concrete cushion 2 is 200 mm. The asphalt in the asphalt sand insulation layer 3 should be selected according to the medium temperature in the storage tank. When the medium temperature in the oil tank is lower than 80 °C, 60# A (or 60# B) road petroleum asphalt or 30# A (or 30# B) building petroleum asphalt is used; the asphalt sand is mixed by 92% - 90% medium and coarse sand and 8% - 10% hot asphalt; in this embodiment, the thickness of the asphalt sand insulation layer 3 is 50 mm, and it slopes from the center to the periphery with a slope of 120:1.

[0038] Step 2, Prefabrication of the storage tank: The storage tank includes a tank bottom plate fixedly arranged on the top of the asphalt sand insulation layer 3, a tank wall plate hermetically and fixedly arranged on the tank bottom plate, and a tank top plate fixedly arranged on the top of the tank wall plate. Multiple accessories are arranged on the tank wall plate and the tank top plate. The accessories include an oil inlet, an oil outlet, a manhole, a visual observation piece, etc.

[0039] Divide the tank bottom plate into multiple edge plates 4 and middle plates 5. One end of the edge plate 4 is arc-shaped, and the dimension of the edge plate 4 along the radius direction of the tank bottom is greater than or equal to 700 mm. After the circumferential splicing of multiple edge plates 4, it is adapted to the outer shape of the tank wall. The middle plate 5 is rectangular, the width of the middle plate 5 is greater than or equal to 1000 mm, and the length is greater than or equal to 2000 mm. The distance between any adjacent welds on the tank bottom plate is greater than or equal to 200 mm. When manufacturing the edge plate 4 and the middle plate 5, cutting lines and standard lines of each edge plate 4 and middle plate 5 need to be marked on the steel plate, and number marks are made on each edge plate 4 and middle plate 5; the number marks are marked with paint in the upper left corner of the steel plate. During assembly, the installation positions of the edge plate 4 and the middle plate 5 can be quickly determined according to the number marks, improving the assembly efficiency. The middle plate 5 is cut by a special semi-automatic cutting machine, and the edge plate 4 is cut manually or by a numerical control cutting machine in the prefabrication yard and then polished. The dimensional deviations of the edge plate 4 and the middle plate 5 need to be within the preset range. The deviation of the edge plate 4 is controlled according to Table 1; the deviation of the middle plate 5 is controlled according to Table 2.

[0040] Table 1 Edge plate deviation

[0041]

[0042]

[0043] Web plate deviation in Table 2

[0044]

[0045] The tank wall is divided into multiple rings from top to bottom. Each ring of the tank wall is composed of multiple wall plates 6 spliced together. When manufacturing the wall plates 6, the cutting lines, standard lines, and three-equal-part alignment lines of the plate length of each wall plate 6 need to be marked on the steel plate, and the size and number markings are carried out on the wall plates 6. The width of the wall plate 6 is greater than or equal to 1000 mm, and the length is greater than or equal to 2000 mm; the deviation of the wall plate 6 is controlled according to Table 3.

[0046] Wall plate deviation in Table 3

[0047]

[0048] One plate should be left as a sealing plate for each ring of wall plates 6. One side of the sealing plate is lengthened by more than 200 mm for the sealing length. After the longitudinal joint assembly dimension of the whole ring of plates (measuring the outer circumference with a tape measure) is determined, the excess plate length is cut off. After the wall plates 6 are cut, the bevel is processed with a planer, angle grinder or special semi-automatic cutting machine according to the bevel type required by the welding scheme. When the wall plates 6 are rolled into an arc with a rolling machine, the length of the pressing head is not less than 300 mm, and the part of the plate outside the rolling bed is supported by a bracket. After the wall plates 6 are rolled into shape, they are immediately placed on the platform and inspected with a template. The arc-shaped wall plates 6 are inspected with a 2-meter-long arc-shaped template in the horizontal direction, and the gap shall not be greater than 4 mm; in the vertical direction, they are inspected with a straight template with a length of not less than 1 meter, and the gap shall not be greater than 1 mm. After the wall plates 6 are processed qualified, they are placed on a special transportation fixture adapted to the radian of the wall plates 6 for stacking, transportation and lifting, effectively preventing deformation.

[0049] The tank top plate includes multiple gore plates and stiffeners fixedly arranged on the inner wall of the gore plates. After the gore plates are cut, they are integrally formed with a vault forming fixture. After the stiffeners are pressed into an arc, they are inspected with an arc-shaped template, and the gap shall not be greater than 2 mm.

[0050] Step 3, assembling the tank bottom plate. Before laying the tank bottom plate, an anti-corrosion coating should be applied to the lower surface of the tank bottom plate, and the area within 50 mm of the edge of each tank bottom plate is not painted. Before laying the tank bottom plate, first draw the outer contour line, cross center line and the indexing line of the weld bead of the edge plate 4 on the surface of the asphalt sand insulation layer 3, and use red paint to mark the indexing value on the ring beam, and measure with a theodolite and a tape measure.

[0051] First, lay the backing plates 7 on the foundation. After the backing plates 7 are laid into a circle, lay the edge plates 4 on the backing plates 7. When laying, use the spacer limit blocks 8 to adjust the interval between adjacent two edge plates 4 to make the interval between adjacent two edge plates 4 consistent, and use the skew iron 10 to adjust the levelness of the edge plates 4. After the adjustment of the whole circle of edge plates 4 is completed, use the portal fixture 9 for fixation.

[0052] Then lay the middle web plate 5. The middle web plate 5 is laid piece by piece from the center of the tank bottom to both ends. After the middle row is laid, based on the middle row, it is laid row by row to both sides. Each row of the middle web plate 5 is laid from the middle to both sides in sequence; after the overall laying of the tank bottom plate is completed, the splicing seams of two adjacent middle web plates 5 are welded; the lap weld between the edge plate 4 and the middle web plate 5 is not welded temporarily as a shrinkage joint. All the tank bottom welds need to be subjected to vacuum inspection according to the requirements of the design and construction specifications.

[0053] Step 4: Install auxiliary equipment. Install the positioning component 11 at the center position of the tank bottom. The positioning component 11 is used to measure the position and levelness of each wall plate 6 relative to the center of the tank bottom. The positioning component 11 is fixedly installed on the support column 110 at the center of the tank bottom plate and the support seat 111 rotatably arranged on the outer wall of the support column 110 through a bearing. A level 112 and a laser displacement sensor 113 are fixedly installed on the support seat 111 through fasteners. Two photosensitive elements 114 are horizontally arranged on the inner side of each wall plate 6. The photosensitive elements 114 are used to receive the optical signals of the level 112 and the laser displacement sensor 113 and convert them into electrical signals, and transmit the electrical signals to the controller and display them on the display of the controller, improving the measurement accuracy and efficiency and avoiding the cumbersome process of repeatedly installing and adjusting with a theodolite in the traditional way. In this embodiment, the support seat 111 is a liftable structure, specifically including a support base and an electric slide table installed on the support base. The level 112 and the laser displacement sensor 113 are installed on the electric slide table, and the height of the level 112 and the laser displacement sensor 113 is controlled by controlling the electric slide table, increasing the measurement range and enabling rapid measurement.

[0054] Install the lifting component 12 on the tank bottom and inside the tank wall. The lifting component 12 is used to lift the assembled tank wall. The lifting component 12 includes a lifting column 120 fixedly installed on the tank bottom plate and a chain block 121 installed at the top of the lifting column 120. The hook at the bottom of the chain block 121 is connected to the wall plate 6, and the wall plate is lifted synchronously as a whole through the chain block 121. The chain block 121 is selected for manual lifting operation, which is simple to operate. The number of chain blocks 121 can be adjusted adaptively according to the size of the storage oil tank, and it has good versatility. It avoids the disadvantages of oil leakage and difficult synchronous control during hydraulic lifting, and is also convenient to be removed and carried out of the storage oil tank.

[0055] Step 5: Assembly of the top ring tank wall. Through the positioning of the positioning component 11, draw the inner circumferential line and outer circumferential line of the top ring tank wall on the tank bottom plate. At intervals along the inner side of the inner circumferential line, arrange several adjustable positioning members 13. Assemble the wall plates 6 according to the numbered markings and corresponding azimuth markings. During assembly, use the positioning component 11 and the square 14 to detect the position, levelness, and perpendicularity of the installation of the wall plate 6. When the perpendicularity, radian, and circumferential length of the entire ring of tank wall meet the requirements, spot-weld the vertical seams between adjacent two wall plates 6, leaving one vertical seam as the vertical shrinkage seam. After spot-welding is completed, perform overall welding of the vertical seams, and finally weld the vertical shrinkage seam.

[0056] The allowable horizontal deviation of the upper openings of adjacent two wall plates: ≤2 mm; the allowable horizontal deviation between any two points on the entire circumference: ≤6 mm; the allowable vertical deviation of the wall plates: ≤3 mm; the allowable deviation of the butt joint misalignment of the vertical welds of the wall plates: ≤1 mm.

[0057] The adjustable positioning member 13 includes an L-shaped support bottom plate 130 fixedly installed on the tank bottom plate and two adjusting bolts 131 adjustably installed on the L-shaped support bottom plate 130 through threads. The two adjusting bolts 131 abut against the inner wall of the wall plate 6, and the position and angle of the wall plate 6 are adjusted through the two adjusting bolts 131. It also includes an adjusting rod 132 hingedly installed between the wall plate 6 and the tank bottom plate. The operator adjusts the perpendicularity of the wall plate 6 by adjusting the length of the adjusting rod 132. The adjustment is simple and convenient. It can not only perform position and angle adjustment, but also maintain the posture of the wall plate 6 after adjustment, facilitating subsequent welding operations. The adjusting rod 132 includes a screw rod and a sleeve adjustably connected through threads. One end of the screw rod is installed on the tank bottom plate through a hinge support, and one end of the sleeve is installed on the inner wall of the wall plate 6 through a hinge support. The length of the adjusting rod 132 is adjusted by rotating the screw rod and the sleeve to achieve the adjustment of the perpendicularity of the wall plate 6. The top view of the L-shaped support bottom plate 130 is trapezoidal.

[0058] After the assembly and welding of the top ring tank wall are completed, install the angle bar at the top of the top ring tank wall. The butt weld of the angle bar is staggered from the vertical seam of the wall plate 6 by a distance greater than 200 mm; the lap joint between the angle bar and the wall plate 6 is temporarily fixed by spot-welding. The angle bar is 16 mm higher than the top of the wall plate, and the local allowable deviation higher than the wall plate: ≤4 mm; the angle bar is closely attached to the wall plate, and the gap between them is not greater than 2 mm; during welding, first weld the butt weld of the angle bar. To prevent deformation, first spot-weld the internal lap welds, and finally spot-weld the external continuous welds. The lap welds are welded after the tank top plate is welded.

[0059] Step 6: Crown installation and assembly. First, assemble two melon skin plates at the axisymmetric positions. After adjusting evenly, carry out tack welding. Then assemble the other melon skin plates and adjust the lap width to 60 mm. When installing the melon skin plates, place their central support members on the top of the support column 110. An installation flange is reserved at the top of the support column 110, which can quickly determine the center position of the crown according to the position of the support column 110, with relatively high splicing efficiency.

[0060] After the melon skin plates are paired up, carry out welding in a backward welding method. Then weld the intermittent welds inside the arch top and the connecting welds of the rib plates. Finally, weld the angle steel at the skirt and install the accessories of the crown opening machine on the crown. The lap width between two adjacent melon skin plates is 60 mm, and the allowable deviation is ±5 mm.

[0061] Step 7: Assembly of the remaining tank walls. Install an internal expansion ring on the inner side of the top ring of the tank wall. The internal expansion ring is fixedly installed on the inner side of the wall plate 6 by using a portal plate. The internal expansion ring is 200 mm away from the lower opening of the top ring of the tank wall. The internal expansion ring is composed of channel steels in 1 / 4 type and is connected into a complete circle by using 15-ton screw jacks.

[0062] Install the second top ring of the tank wall at the corresponding position on the outer side of the top ring of the tank wall, leaving a live opening. Connect the internal expansion ring with the lifting assembly. Lift the top ring of the tank wall above the position where the two rings of tank walls are paired up through the lifting assembly. Assemble the second top ring of the tank wall in the way of Step 3. After the welding of the second top ring of the tank wall is completed, splice the top ring of the tank wall and the second top ring of the tank wall through the lifting assembly. Detect the position and attitude of the top ring of the tank wall and the second top ring of the tank wall through the positioning assembly 10 and adjust manually. After the position and attitude of the two are adjusted to be qualified, carry out tack welding and fix it. Conduct an inspection on the shape and size of the tank wall. After the inspection is qualified, weld the circumferential welds of the top ring of the tank wall and the second top ring of the tank wall. Lift, pair up and install the third and fourth rings of the tank walls from top to bottom in the above-mentioned operation until the assembly of the bottom layer of the tank wall is completed. The longitudinal welds of each ring of the wall plates should be staggered one by one in the same direction in each ring, and the spacing should be 1 / 3 of the plate length and not less than 500 mm. For the angularity of the vertical welds, use a 1-m long arc-shaped template to check, and the angularity ≤ 10 mm. The local concavo-convex deformation of the tank wall ≤ 13 mm.

[0063] The welding of the circumferential welds of the tank wall must be carried out after all the longitudinal welds of the upper and lower two rings of the wall plates are welded completely, and try to avoid using the positions within 300 mm on both sides of the T-joint part as the starting and ending points of welding. The welding of the circumferential welds of the wall plates adopts manual arc welding, and the repair of the welds adopts manual arc welding. First, weld the outer weld pass of the circumferential weld, and then weld the inner weld pass. The inner weld pass is subjected to automatic carbon arc air gouging for root cleaning and then welded after grinding with a grinding wheel. After the longitudinal and circumferential welds of the tank wall are welded and inspected to be qualified, all the longitudinal and circumferential welds inside the tank wall should be ground to be flush with the base metal, and no weld reinforcement should be left.

[0064] Step 8: Assemble the bottom course of the tank wall and the tank bottom plate. After the installation of the bottom course of the tank wall is completed, carry out the opening, nozzle connection and installation of the tank roof of the constructed tank. First, spot-weld the bottom course of the tank wall and the tank bottom plate, and then carry out full welding after measuring the dimensions and shape of the tank body; after welding is completed, weld the shrinkage seams between the edge plate 4 and the middle plate 5 and between the edge plate 5 and the edge plate 5; temporarily weld between the middle plate 5 and the edge plate 4 through a temporary positioning plate to control the welding deformation. After welding is completed, conduct a vacuum test. The distance between the longitudinal weld of the bottom course of the tank wall and the butt weld of the tank bottom edge plate shall not be less than 200 mm.

[0065] For the welding of the large fillet weld between the bottom course of the tank wall and the tank bottom plate, first carry out welding simultaneously in the same direction inside and outside the tank by means of sectional backward welding or skip welding, and conduct 100% magnetic particle or penetrant inspection after welding; then the filling and capping layers are welded in sections along the same direction by four angle submerged arc automatic welding machines symmetrically distributed; during operation, weld the inside first and then the outside. Before welding, reinforcement supports shall be carried out inside the bottom course of the tank wall, and the distance between adjacent two reinforcement support points shall be less than or equal to 1200 mm, and the reinforcement supports shall be removed after the shrinkage seam of the tank bottom is welded. The surface of the large fillet weld shall ensure smooth transition, and the inside weld shall be concave, otherwise it shall be formed by grinding with a grinding wheel.

[0066] The above embodiments are only several descriptions of the concept and implementation of the present invention, and do not limit it. Under the concept of the present invention, the technical solutions without substantial transformation are still within the protection scope.

Claims

1. A method for assembling an assembled oil storage tank structure, characterized in that: The assembling method comprises the following steps: Step 1: foundation construction: construct multiple foundation piles at the bottom of the oil storage tank installation area, lay a perlite concrete cushion layer in the area, lay an asphalt sand insulation layer on top of the perlite concrete cushion layer; set position marks on the asphalt sand insulation layer; Step 2: prefabricate the oil storage tank, divide the tank bottom plate into multiple edge plates and middle plates; the tank wall is composed of multiple wall panels, and the cutting line, standard line, and three-equal grouping lines of the plate length of each wall panel are marked on the steel plate, and the size and number are marked on the wall panel; the tank top plate includes multiple melon skin plates and reinforcing ribs fixed on the inner wall of the melon skin plates. After the melon skin plates are cut, they are integrally formed using an arch forming mold; Step 3: Assemble the tank bottom plate. First, lay the pad on the foundation. After the pad is laid into a circle, lay the edge plate on the pad. When laying, use the spacing limit block to adjust the interval between two adjacent edge plates. After the overall adjustment is completed, use the gantry clamp to fix it; then lay the middle plate. The middle plates are laid piece by piece from the center of the tank bottom to both ends. After the middle row is laid, the middle row is used as the basis to lay rows on both sides. Each row of middle plates is laid from the middle to both sides in sequence; after the overall laying of the tank bottom plate is completed, the joint seams of the two adjacent middle plates are welded; the lap welds between the edge plate and the middle plate are used as contraction seams and are not welded for the time being; Step 4: Installation of auxiliary equipment: Install a positioning assembly at the center of the tank bottom. The positioning assembly is used to measure the position and horizontality of each wall panel relative to the center of the tank bottom; install a lifting assembly on the tank bottom and inside the tank wall. The lifting assembly is used to lift the assembled tank wall; the positioning assembly includes a support column fixedly installed at the center of the tank bottom plate and a support seat rotatably arranged on the support column. A level and a laser displacement sensor are fixedly installed on the support seat. Two photosensitive elements are horizontally arranged on the inside of each wall panel. The photosensitive elements are used to receive light signals from the level and the laser displacement sensor and convert them into electrical signals; Step 5, assembling the top ring tank wall, through the positioning of the positioning component, draw the inner circumference line and the outer circumference line of the top ring tank wall on the tank bottom plate, and place several adjustable positioning parts along the inner side of the inner circumference. The wall panels are assembled according to the number marks and corresponding orientation marks. During assembly, the positioning component and the square ruler are used to detect the installation position, horizontality and verticality of the wall panels. When the verticality, arc and circumference of the entire circle of the tank wall meet the requirements, the vertical seams of the two adjacent wall panels are spot welded, leaving a vertical seam as a vertical contraction seam. After the spot welding is completed, the vertical seams are welded as a whole, and finally the vertical contraction seams are welded; the adjustable positioning parts include an L-shaped support bottom plate fixedly mounted on the tank bottom plate and two adjusting bolts adjustably mounted on the L-shaped support bottom plate, and also include an adjusting rod hingedly mounted between the wall panel and the tank bottom plate, and the verticality of the wall panel is adjusted by adjusting the length of the adjusting rod; Step 6: Roof assembly: first assemble two melon skin boards at the axially symmetrical position, adjust them evenly and then weld them, then assemble other melon skin boards and adjust the overlap width to 60mm; after the melon skin boards are assembled, they are welded by step-back welding, and then the intermittent welds on the inner side of the arch and the connecting welds of the ribs are welded; finally, the hemming angle steel is welded and the roof opening machine accessories are installed; Step seven, assemble the remaining tank walls, install the inner expansion ring on the inner side of the top ring tank wall, and use the gantry plate to fix the inner expansion ring on the inner side of the wall plate; install the secondary top ring tank wall on the outer side of the top ring tank wall according to the corresponding position, and reserve a live opening; connect the inner expansion ring with the lifting assembly, lift the top ring tank wall to above the assembly position of the two rings of tank walls through the lifting assembly, and assemble the secondary top ring tank wall according to the method of step three. After the welding of the secondary top ring tank wall is completed, the top ring tank wall and the secondary top ring tank wall are spliced ​​by the lifting assembly, and the position and posture of the two are adjusted and then spot welded and fixed. The tank wall is checked for shape and size. After the inspection is qualified, the annular weld of the top ring tank wall and the secondary top ring tank wall is welded; the third and fourth rings of tank walls from top to bottom are lifted and assembled and installed according to the above operations until the bottom tank wall is assembled; Step eight, assemble the bottom tank wall and the tank bottom plate. After the installation of the bottom tank wall is completed, construct the tank body opening, pipe connection and top plate installation; first spot weld the bottom tank wall and the tank bottom plate, measure the size and shape of the tank body and then perform full welding; after welding, weld the shrinkage seams between the edge plate and the middle plate and between the edge plates; after welding, perform vacuum inspection.

2. The method for assembling an assembled oil storage tank structure according to claim 1, characterized in that: The cutting lines and standard lines of each edge plate and middle plate are drawn on the steel plate, and each edge plate and middle plate is numbered and marked; one end of the edge plate is arc-shaped, and the dimension of the edge plate along the radius direction of the tank bottom is greater than or equal to 700mm; the middle plate is rectangular, and the width of the middle plate is greater than or equal to 1000mm, and the length is greater than or equal to 2000mm.

3. The method for assembling an assembled oil storage tank structure according to claim 1 or 2, characterized in that: In the step three, the middle plate and the edge plate are temporarily welded via a temporary positioning plate to control the welding deformation.

4. The method for assembling an assembled oil storage tank structure according to claim 1, characterized in that: In the step three, before the tank bottom plate is laid, an anti-corrosion coating should be applied to the lower surface of the tank bottom plate, and the area within 50 mm of the edge of each tank bottom plate shall not be painted.

5. The method for assembling an assembled oil storage tank structure according to claim 1 or 4, characterized in that: In step 4, the lifting assembly includes a lifting column fixedly mounted on the tank bottom plate and a fall chain mounted on the top of the lifting column, and the hook of the fall chain is connected to the wall panel to lift the wall panel through the fall chain.

6. The method for assembling an assembled oil storage tank structure according to claim 1, characterized in that: In step five, after the top ring tank wall is assembled and welded, an edge angle steel is installed on the top of the top ring tank wall. The butt weld of the edge angle steel is staggered with the vertical seam of the wall panel, and the lap seam between the edge angle steel and the wall panel is temporarily fixed by spot welding.

7. The method for assembling an assembled oil storage tank structure according to claim 1, characterized in that: In step seven, the inner expansion ring is 200 mm away from the lower opening of the top ring tank wall. The inner expansion ring is composed of channel steel divided into 1 / 4 types and connected into a complete circle by a 15-ton screw jack.

8. The method for assembling an assembled oil storage tank structure according to claim 1, characterized in that: In the step eight, the welding of the large angle weld between the bottom tank wall and the tank bottom plate is first performed by simultaneously using the segmented back-welding or skip welding method along the same direction inside and outside the tank, and a 100% magnetic powder or penetration inspection is performed after welding; then the filling and covering layers are symmetrically distributed and segmentedly welded along the same direction by four angular submerged arc automatic welding machines; during the operation, the inside is welded first and then the outside.

9. The method for assembling an assembled oil storage tank structure according to claim 8, characterized in that: Before welding, reinforcement support must be provided on the inner side of the bottom tank wall. The distance between two adjacent reinforcement support points should be less than or equal to 1200mm. The reinforcement support must be removed after the tank bottom shrinkage seam welding is completed.

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