LNG storage tank water pressure test equipment and method

Abstract

The present invention discloses a water pressure test device and method for LNG storage tanks, which belongs to the technical field of LNG storage tanks. A water pressure test device and method for LNG storage tanks, comprising an outer tank and an inner tank wall panel, further comprising a cleaning kit, which is arranged inside the inner tank wall panel, the cleaning kit comprising a prefabricated rail rod, an annular hanging rail, a dredging nozzle and a wall panel cleaning machine, the annular hanging rail being slidably connected to the prefabricated rail rod through a vertical support shaft, and the wall panel cleaning machine being installed on the outer surface of the annular hanging rail. In order to solve the problem that it still takes a lot of manpower and time to effectively clean the inner wall of the tank body during the drainage process, the wall panel cleaning machine is controlled to rotate along the annular hanging rail, and the inner wall of the storage tank is cleaned downward in sequence. The sewage generated by the cleaning will flow down along the inner wall to the bottom of the tank, and then the sewage will be flushed to the central area of the bottom of the tank through the high-pressure nozzle on the dredging nozzle, and the cleaning operation of the silt at the bottom of the tank can also be completed at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of LNG storage tanks, and in particular to a LNG storage tank water pressure test device and method. Background Art

[0002] LNG storage tanks are specialized equipment for storing liquefied natural gas. When the natural gas entering the LNG tank is cooled to -168°C, it is liquefied. This liquefaction saves storage and transportation space. Therefore, LNG storage tanks are extremely important equipment in the natural gas storage and transportation process.

[0003] However, due to the special structure of LNG storage tanks, all of their pipe openings and manholes are on the tank top, and the tank water filling test requires tens of thousands of tons of water. Whether it is water intake or drainage, it can only be carried out using the appropriate pipe openings on the tank top, which brings trouble to the water filling test.

[0004] Moreover, it takes a lot of manpower and time to effectively clean the inner wall of the tank during the drainage process; therefore, it does not meet the existing needs, and a LNG storage tank water pressure test device and method are proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide an LNG storage tank water pressure test device and method, which controls the wall panel cleaning machine to rotate along the circular hanging rail, and cleans the inner wall of the storage tank downward in sequence. The sewage generated by cleaning will flow down along the inner wall to the bottom of the tank, and then the sewage will be flushed to the central area of the tank bottom through the high-pressure nozzle on the dredging nozzle. At the same time, the cleaning operation of the silt at the bottom of the tank can also be completed, which can solve the problems in the existing technology.

[0006] To achieve the above object, the present invention provides the following technical solution: an LNG storage tank water pressure test equipment, comprising an outer tank and an inner tank wall plate,

[0007] It also includes a cleaning kit, which is arranged inside the inner tank wall panel. The cleaning kit includes a prefabricated rail rod, an annular hanging rail, a dredging nozzle and a wall panel cleaning machine. The annular hanging rail is slidably connected to the prefabricated rail rod through a vertical support shaft. The wall panel cleaning machine is installed on the outer surface of the annular hanging rail. The dredging nozzle is installed on the bottom of the prefabricated rail rod by screws. The back of the dredging nozzle and the wall panel cleaning machine are both provided with water pipe interfaces. The inner surface of the oblique side of the dredging nozzle is provided with high-pressure nozzles distributed in a ring shape.

[0008] Preferably, the outer surface of the wall panel cleaning machine is provided with a spray plate, the outer surface of the spray plate is provided with an array nozzle, and cleaning turntables are provided at both ends of the spray plate, and the cleaning turntable is connected to the wall panel cleaning machine through a motor for rotation.

[0009] Preferably, the wall panel cleaning machine is slidably connected to the annular hanging rail through a pulley groove, and folding shovels are provided at both ends of the wall panel cleaning machine, and the folding shovels are connected to the wall panel cleaning machine through an electrically controlled rotating shaft.

[0010] Preferably, an inner tank ring plate is provided below the inner tank wall plate, a concrete ring beam is provided on the outer side of the bottom of the inner tank ring plate, and a wall corner protection layer is installed between the concrete ring beam and the outer tank.

[0011] Preferably, an upper insulation layer and a lower insulation layer are provided below the inner tank ring plate, a second bottom plate is provided between the upper insulation layer and the lower insulation layer, and an air barrier bottom plate is provided below the lower insulation layer.

[0012] Preferably, marking angle steels are provided on all four sides of the interior of the outer tank, and there are a plurality of marking angle steels, and a concrete wall is provided inside the outer tank.

[0013] A method for testing LNG tank water pressure testing equipment comprises the following steps:

[0014] Step 1: 8 permanent settlement observation marks are evenly distributed around the outer tank, i.e. starting from 0°, one observation point is set every 45°. 25 observation points are marked on the lower surface of the outer tank foundation. The observation reference point should be set at any position 100m away from the tank body;

[0015] Step 2: Weld steel to the corner protection plate at 8 locations inside the tank corresponding to the outer tank markings as inner tank settlement observation marks, and paint fluorescent paint 300mm below the angle steel;

[0016] Step 3: Use water inlet equipment to flush water into the storage tank through the N2 inlet pipe. The water filling speed should be controlled at no more than 0.6m / h. The inner tank needs to be filled with water continuously. The settlement observation of each key point should stop filling with water for one hour. After obtaining correct observation data, continue filling with water until the test water level is reached.

[0017] Step 4: Analyze the water level rise record. If it rises too fast, close the water inlet valve and control the rising speed to below 0.6m / h.

[0018] Step 5: When the water filling process is completed, drain the test water out of the tank. Before draining, observe the settlement, start the drainage equipment, use the deep well pump to drain the water out of the tank, open the return pipe valve, and drain the water to the designated sewer;

[0019] Step 6: When the water level is drained to 3 / 4 of the height and after it is emptied, observe the settlement rebound of the inner and outer tanks respectively and make records. When the water is drained to a shallower level, use the stirring method to discharge the sediment as much as possible from the water pump. After draining all the water, clean the bottom of the tank.

[0020] Preferably, in step three, the water level height mark should be marked in advance on the outside of the pump well pipe with a marker, with a grid every 500mm, and the scale value clearly marked. The pump well platform and ladder should be used for observation, and a small tape measure should be used to measure and record the reading accurately to ±2mm.

[0021] Preferably, in step 4, during the test, regular inspections are required, including whether the concrete ring beam has cracks, whether the plywood, Teflon, and glass cloth have protrusions, and the tightness of the welds under the water level.

[0022] Preferably, in step 4, when the liquid level in the tank reaches the test water level, the tank body welds, including the fillet welds between the tank wall and the bottom, are checked for watertightness by visual inspection for 24 hours, and no leakage is found.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. In the present invention, after the test is completed, the vertical support shaft on the inner side of the annular hanging rail is installed on the surface of the prefabricated rail rod, and the dredging nozzle is installed at the bottom of the prefabricated rail rod at a height of 30-50 cm from the bottom plate of the inner tank. After the installation is completed, the soft water pipe is connected to the dredging nozzle and the wall panel cleaning machine on the outer side of the annular hanging rail respectively. The pipe connecting the wall panel cleaning machine needs to reserve a certain length to meet the lifting and sliding requirements of the annular hanging rail and the wall panel cleaning machine. Finally, the annular hanging rail is raised to the highest point of the inner tank, and the wall panel cleaning machine is controlled to rotate along the annular hanging rail to clean the inner wall of the storage tank downward in turn. The sewage generated by the cleaning will flow down along the inner wall to the bottom of the tank, and then the sewage will be flushed to the central area of the tank bottom through the high-pressure nozzle on the dredging nozzle, and the cleaning operation of the siltation at the bottom of the tank can also be completed at the same time.

[0025] 2. In the present invention, the cleaning turntable on the surface of the wall panel cleaning machine can be attached to the inner wall of the inner tank. During the cleaning process, the cleaning liquid is first sprayed on the inner wall surface through the spray plate. During the sliding of the wall panel cleaning machine, the residues on the inner wall surface are washed away by the high-speed rotating cleaning turntable. During the movement, the folding shovels at both ends of the wall panel cleaning machine will be flipped outward and unfolded, and also attached to the surface of the inner wall. The folding shovel in the forward direction can scrape off some larger and loose residues before cleaning, which can improve the efficiency of subsequent rotary flushing, and the scraper in the other end direction can scrape off the flushing residues attached to the inner wall after flushing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the overall front view of the present invention; Figure 2 This is a schematic structural diagram of the cleaning kit of the present invention;

[0027] Figure 3 It is a structural schematic diagram of the wall panel cleaning machine of the present invention; Figure 4This is a schematic diagram of the inner tank wall structure of the present invention;

[0028] Figure 5 This is a schematic diagram of the outer tank structure of the present invention; Figure 6 This is a schematic diagram of the inner tank structure of the present invention;

[0029] Figure 7 It is a schematic diagram of the settlement change observation of the present invention.

[0030] In the figure: 1. Outer tank; 2. Inner tank wall panel; 3. Corner protection layer; 4. Concrete wall; 5. Inner tank ring plate; 6. Cleaning kit; 201. Concrete ring beam; 301. Marking angle steel; 501. Upper insulation layer; 502. Second layer bottom plate; 503. Lower insulation layer; 504. Air barrier bottom plate; 601. Prefabricated rail rod; 602. Ring hanging rail; 603. Dredging nozzle; 604. Wall panel cleaning machine; 6011. Vertical support shaft; 6031. High-pressure nozzle; 6041. Pulley groove; 6042. Spray plate; 6043. Cleaning turntable; 6044. Folding shovel plate. DETAILED DESCRIPTION

[0031] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention. Figure 1-2 The present invention provides an embodiment of an LNG storage tank hydraulic test device, comprising an outer tank 1 and an inner tank wall panel 2, and also comprising a cleaning kit 6, which is arranged inside the inner tank wall panel 2, the cleaning kit 6 comprising a prefabricated rail rod 601, an annular hanging rail 602, a dredging nozzle 603 and a wall panel cleaning machine 604, the annular hanging rail 602 being slidably connected to the prefabricated rail rod 601 via a vertical support shaft 6011, the wall panel cleaning machine 604 being mounted on the outer surface of the annular hanging rail 602, the dredging nozzle 603 being mounted on the bottom of the prefabricated rail rod 601 via screws, the back of the dredging nozzle 603 and the wall panel cleaning machine 604 being provided with a water pipe interface, and the inner surface of the oblique side of the dredging nozzle 603 being provided with a ring-shaped distribution of high-pressure nozzles 6031;

[0032] After the test is completed, the water inside the storage tank is drained, and then the prefabricated rail rod 601 is placed inside the inner tank. The number of prefabricated rail rods 601 and the radius size of the annular hanging rail 602 and the dredging nozzle 603 need to be selected according to the actual size of the inner tank. At least three sets of prefabricated rail rods 601 are required. The prefabricated rail rods 601 are fixed in the inner tank at equal intervals. After the prefabricated rail rods 601 are fixed, the vertical support shaft 6011 on the inner side of the annular hanging rail 602 is installed on the surface of the prefabricated rail rod 601, and the dredging nozzle 603 is installed at the bottom of the prefabricated rail rod 601 at a height of 30-50 cm from the bottom plate of the inner tank. After the installation is completed, the soft water pipe The siding cleaning machine 604 is respectively connected to the dredging nozzle 603 and the outside of the annular hanging rail 602. A certain length of the pipe connecting the siding cleaning machine 604 needs to be reserved to meet the lifting and lowering requirements of the annular hanging rail 602 and the sliding requirements of the siding cleaning machine 604. Finally, the annular hanging rail 602 is raised to the highest point of the inner tank, and the siding cleaning machine 604 is controlled to rotate along the annular hanging rail 602 to clean the inner wall of the storage tank downward in turn. The sewage generated by cleaning will flow down along the inner wall to the bottom of the tank, and then the sewage will be flushed to the central area of the bottom of the tank through the high-pressure nozzle 6031 on the dredging nozzle 603. At the same time, the cleaning operation of the silt at the bottom of the tank can also be completed.

[0033] The outer surface of the wall panel cleaning machine 604 is provided with a spray plate 6042, and the outer surface of the spray plate 6042 is provided with an array of nozzles. A cleaning turntable 6043 is provided at both ends of the spray plate 6042. The cleaning turntable 6043 is rotationally connected to the wall panel cleaning machine 604 via a motor. The wall panel cleaning machine 604 is slidingly connected to the annular hanging rail 602 via a pulley groove 6041. A folding shovel plate 6044 is provided at both ends of the wall panel cleaning machine 604. The folding shovel plate 6044 is connected to the wall panel cleaning machine 604 via an electrically controlled rotating shaft.

[0034] The cleaning turntable 6043 on the surface of the wall panel cleaning machine 604 can be attached to the inner wall of the inner tank. During the cleaning process, the cleaning liquid is first sprayed on the inner wall surface through the spray plate 6042. As the wall panel cleaning machine 604 slides, the high-speed rotating cleaning turntable 6043 is used to rinse off the residue on the inner wall surface. During the movement, the folding scrapers 6044 at both ends of the wall panel cleaning machine 604 will flip outward and unfold, also attached to the surface of the inner wall. The folding scraper 6044 in the forward direction can scrape off some large and loose residues before cleaning, which can improve the efficiency of subsequent rotary rinsing. The scraper on the other end can scrape off the washing residue attached to the inner wall after rinsing. Figure 3An inner tank ring plate 5 is installed below the inner tank wall plate 2. A concrete ring beam 201 is installed on the outside of the bottom of the inner tank ring plate 5. A wall corner protection layer 3 is installed between the concrete ring beam 201 and the outer tank 1. An upper insulation layer 501 and a lower insulation layer 503 are installed below the inner tank ring plate 5. A second bottom plate 502 is installed between the upper insulation layer 501 and the lower insulation layer 503. An air barrier bottom plate 504 is installed below the lower insulation layer 503. Marking angle steels 301 are installed on all four sides of the inner tank 1. There are multiple marking angle steels 301. A concrete wall 4 is installed inside the outer tank 1. Please refer to Figure 4-7 Based on the above-mentioned LNG storage tank water pressure test equipment, this embodiment proposes a detection method for the LNG storage tank water pressure test equipment, including the following steps:

[0035] Step 1: 8 permanent settlement observation marks are evenly distributed around the outer tank 1, that is, starting from 0°, an observation point is set every 45°. 25 observation points are marked on the lower surface of the foundation of the outer tank 1. The observation reference point should be set at any position 100m away from the tank body;

[0036] Step 2: Weld steel to the corner protection plate at 8 positions inside the tank corresponding to the mark 1 on the outer tank as the inner tank settlement observation mark, and paint fluorescent paint on the 300mm below the angle steel and on the angle steel to facilitate observation and attract the attention of operators;

[0037] Step 3: Use water inlet equipment to flush water into the storage tank through the N2 inlet pipe. The water filling speed should be controlled at no more than 0.6m / h. The inner tank needs to be filled with water continuously. The settlement observation of each key point should stop filling with water for one hour. After obtaining correct observation data, continue filling with water until the test water level. During the water filling process, there must be sufficient exhaust ports to ensure that the outer tank is not pressurized. The two manholes remain open. Water inlet system settings:

[0038] a. Install a temporary pump in the new fire pump room. Connect the pump outlet to the fire protection pipe system of the storage tank. Use temporary pipes to connect the unconnected parts of the fire protection system pipes and fill the storage tank with water. Use the fire pump in the old tank to pump water from the old fire water pool through the old fire protection pipes into the new fire protection system pipes and then fill the storage tank. Step 4: Analyze the water level rise records. If it is rising too fast, close the water inlet valve and control the rise rate to below 0.6m / h. Step 5: After the water filling process is completed, drain the test water out of the tank. Before draining, conduct a settlement observation, start the drainage equipment, drain the water out of the tank with a deep well pump, open the return pipe valve, and drain the water to the designated sewer. During the drainage process, there must be sufficient air intakes and at least one manhole must remain open.

[0039] Drainage system setup: Since the deep well pump cannot drain all the water about 350mm below the surface (about 758t), a 10m³ water collection tank is installed at the bottom of the deep well pump. A small submersible pump is used to pump the remaining water into the water collection tank and then the deep well pump is used to pump it out.

[0040] c. The water that cannot be pumped out by the submersible pump is about 100mm deep and needs to be manually cleared into the water collection tank.

[0041] d. Finally, use a large vacuum cleaner to clean the water on the bottom plate

[0042] Step 6: When the water level is drained to 3 / 4 of the height and after it is emptied, observe the settlement rebound of the inner and outer tanks 1 respectively and make a record. When the water is drained to a shallower level, use the stirring method to make the sediment be discharged from the water pump as much as possible. After the water is drained, clean the bottom of the tank;

[0043] S1: original observation before water filling begins;

[0044] S2: Every time the water volume increases by 1 / 4 (3.87m3), 1 / 2 (7.73m3), 3 / 4 (11.6m3) and full (15.463m3) or every 24 hours of water filling;

[0045] S3: Start draining;

[0046] S4: drain to 3 / 4 of the water depth;

[0047] S5: The water in the tank is drained.

[0048] Subsidence observation results:

[0049]

[0050] Test results:

[0051] 1) The hydraulic tests of two 50,000m³ LNG storage tanks were successfully completed, indicating that the water filling and drainage systems are suitable, and the selected temporary water filling and drainage pumps are operating normally and performing well;

[0052] 2) During the test, welds below the test water pressure were inspected and found to be leak-free. The concrete ring beam was in good condition. After draining the water, the bottom plate welds were vacuum-tested and all passed.

[0053] 3) Settlement observation results show that there is no abnormal settlement of the outer tank and the inner tank.

[0054] In step 3, the water level should be marked on the outside of the pump well pipe in advance with a marker pen, with a grid every 500mm. The scale value should be clearly marked, and the water level should be observed using a pump well platform and ladder. The water level should be recorded with a small tape measure to an accuracy of ±2mm.

[0055] In step 4, during the test, regular inspections are required to check whether there are cracks in the concrete ring beam, whether there are protrusions in the plywood, Teflon, and glass cloth, and the tightness of the welds under the water level;

[0056] When the liquid level in the tank reaches the test water level, check the tank welds for 24 hours, including the fillet welds between the tank wall and the bottom, and check their watertightness with the naked eye. The results show that there is no leakage.

[0057] Working principle: After the test is completed, the water inside the storage tank is drained, and then the prefabricated rail rod 601 is placed inside the inner tank. The bottom of the prefabricated rail rod 601 is connected and fixed to the tank body by bolts. The number of prefabricated rail rods 601 and the radius size of the ring hanging rail 602 and the dredging nozzle 603 need to be selected according to the actual size of the inner tank. At least three sets of prefabricated rail rods 601 are required. The prefabricated rail rods 601 are fixed in the inner tank at equal intervals. After the prefabricated rail rods 601 are fixed, the inner side of the ring hanging rail 602 is fixed. The vertical support shaft 6011 is installed on the surface of the prefabricated rail rod 601, and the dredging nozzle 603 is installed at the bottom of the prefabricated rail rod 601 at a height of 30-50 cm from the bottom plate of the inner tank. After the installation is completed, the soft water pipe is connected to the dredging nozzle 603 and the wall panel cleaning machine 604 outside the annular hanging rail 602 respectively. The pipe connecting the wall panel cleaning machine 604 needs to reserve a certain length to meet the lifting and sliding requirements of the annular hanging rail 602 and the wall panel cleaning machine 604. Finally, the annular hanging rail 602 is raised When the cleaning machine 604 reaches the highest point of the inner tank, the cleaning machine 604 is controlled to rotate along the annular hanging rail 602. The cleaning turntable 6043 on the surface of the cleaning machine 604 can be attached to the inner wall of the inner tank. During the cleaning process, the cleaning liquid is first sprayed on the inner wall surface through the spray plate 6042. During the sliding process of the cleaning machine 604, the high-speed rotating cleaning turntable 6043 is used to wash away the residue on the inner wall surface. During the movement, the folding shovels 6044 at both ends of the cleaning machine 604 will flip outward. Unfolded and also attached to the surface of the inner wall, the folding shovel 6044 in the forward direction can scrape off some larger and loose residues before cleaning, which can improve the efficiency of subsequent rotary flushing, and the scraper in the other end direction can scrape off the flushing residues attached to the inner wall after flushing. The sewage generated by cleaning will flow down along the inner wall to the bottom of the tank, and then the high-pressure nozzle 6031 on the dredging nozzle 603 will flush the sewage to the central area of the bottom of the tank, and at the same time, the cleaning operation of the silt at the bottom of the tank can also be completed.

[0058] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0059] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A detection method for LNG storage tank water pressure test equipment, the LNG storage tank water pressure test equipment includes an outer tank and an inner tank wall panel, and also includes a cleaning kit, which is arranged inside the inner tank wall panel, the cleaning kit includes a prefabricated rail rod, an annular hanging rail, a dredging nozzle and a wall panel cleaning machine, the annular hanging rail is slidably connected to the prefabricated rail rod through a vertical support shaft, the wall panel cleaning machine is installed on the outer surface of the annular hanging rail, the dredging nozzle is installed at the bottom of the prefabricated rail rod by screws, the back of the dredging nozzle and the wall panel cleaning machine are both provided with water pipe interfaces, the inner surface of the oblique side of the dredging nozzle is provided with a ring-shaped high-pressure nozzle; the outer surface of the wall panel cleaning machine is provided with a spray plate, the outer surface of the spray plate is provided with an array nozzle, and both ends of the spray plate are provided with cleaning rotary The disc, the cleaning turntable and the wall panel cleaning machine are connected to each other through a motor rotation; the wall panel cleaning machine is slidably connected to the annular hanging rail through a pulley groove, and folding shovels are provided at both ends of the wall panel cleaning machine, and the folding shovels are connected to the wall panel cleaning machine through an electrically controlled rotating shaft; an inner tank ring plate is provided under the inner tank wall plate, and a concrete ring beam is provided on the outer side of the bottom of the inner tank ring plate, and a wall corner protection layer is installed between the concrete ring beam and the outer tank; an upper insulation layer and a lower insulation layer are provided under the inner tank ring plate, and a second bottom plate is provided between the upper insulation layer and the lower insulation layer, and an air barrier bottom plate is provided under the lower insulation layer; marking angle steels are provided on all sides of the interior of the outer tank, and there are multiple marking angle steels, and a concrete wall is provided inside the outer tank; it is characterized in that, The detection method comprises the following steps: Step 1: 8 permanent settlement observation marks are evenly distributed around the outer tank, i.e. starting from 0°, one observation point is set every 45°. 25 observation points are marked on the lower surface of the outer tank foundation. The observation reference point should be set at any position 100m away from the tank body; Step 2: Weld steel to the corner protection plate at 8 locations inside the tank corresponding to the outer tank markings as inner tank settlement observation marks, and paint fluorescent paint 300mm below the angle steel; Step 3: Use water inlet equipment to flush water into the storage tank through the N2 inlet pipe. The water filling speed should be controlled at no more than 0.6m / h. The inner tank needs to be filled with water continuously. The settlement observation of each key point should stop filling with water for one hour. After obtaining correct observation data, continue filling with water until the test water level is reached. Step 4: Analyze the water level rise record. If it rises too fast, close the water inlet valve and control the rising speed to below 0.6m / h. Step 5: When the water filling process is completed, drain the test water out of the tank. Before draining, observe the settlement, start the drainage equipment, use the deep well pump to drain the water out of the tank, open the return pipe valve, and drain the water to the designated sewer; Step 6: When the water level is drained to 3 / 4 height and after it is emptied, observe the settlement rebound of the inner and outer tanks respectively and make records. When the water is drained to a shallower level, use the stirring method to discharge the sediment from the water pump. After draining all the water, clean the bottom of the tank.

2. The detection method of the LNG storage tank water pressure test equipment according to claim 1, characterized in that: In step three, the water level height mark should be marked in advance on the outside of the pump well pipe with a marker, with a grid every 500mm, and the scale value clearly marked. It should be observed using the pump well platform and ladder, and measured with a small tape measure to record the reading accurately to ±2mm.

3. The detection method of the LNG storage tank water pressure test equipment according to claim 1, characterized in that: In step 4, during the test, regular inspections are carried out to check whether there are cracks in the concrete ring beam, whether there are protrusions of the plywood, Teflon, and glass cloth, and the tightness of the welds under the water level.

4. The detection method of the LNG storage tank water pressure test equipment according to claim 1, characterized in that: In step 4, when the liquid level in the tank reaches the test water level, check the tank welds, including the fillet welds between the tank wall and the bottom, for 24 hours and visually inspect their watertightness.

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