A method for installing and positioning a LNG liquid cargo tank radar liquid level gauge

Abstract

The application discloses a kind of LNG liquid cargo tank radar liquid level gauge installation positioning method, and the flange level is ensured by spirit level from front and back two directions along flange diameter measurement adjustment, laser positioning sleeve is prepared for placing laser emission instrument, and the center point is determined by the method of rotating laser equipment to 0 °, 90 °, 180 °, 270 ° respectively dotting connecting line.Processing and preparation laser positioning sleeve are used to place laser emission instrument, and the center point is determined by rotating laser equipment to 0 °, 90 °, 180 °, 270 ° respectively dotting connecting line.Machining is used to make pipe clamp positioning sleeve, accurate positioning of pipe clamp is carried out, measurement error of steel ruler is reduced, and installation progress is accelerated.After installation, retest is carried out by laser, the center hole of all positioning templates is ensured to be passed through by laser, and correct installation is ensured.The application effectively improves work efficiency, and the center is determined by the method of rotating laser and 4-point intersection positioning, which is accurate and reliable.Compared with the way of pulling steel wire, it is more accurate and has lower labor intensity.Compared with the way of using physical trial fitting, the damage risk of waveguide tube and other parts can be reduced.

Description

Technical Field

[0001] This invention relates to the field of radar level gauges for LNG cargo tanks, and in particular to a method for installing and positioning a radar level gauge for LNG cargo tanks. Background Technology

[0002] Most liquid cargo tanks are equipped with radar level gauges to detect the liquid level inside the tank and determine the actual liquid volume. The level gauges require high positioning and installation accuracy, typically necessitating on-site installation guidance from the manufacturer's service engineers. However, components such as the radar tube support and base must be completed before the tank's hydraulic test; welding work related to the tank is prohibited after the test. Furthermore, radar piping and shielding devices must be installed after the hydraulic test to prevent damage and contamination. Therefore, the entire installation process is lengthy, requiring repeated appointments with the manufacturer's service engineers. The manufacturer's long service period means that the service engineer's availability directly impacts the tank's construction timeline. Summary of the Invention

[0003] The purpose of this invention is to provide a method for installing and positioning radar level gauges for LNG cargo tanks. This method uses a level and laser for positioning, which speeds up the installation process, reduces errors, and reduces the time dependence on service engineers. Service engineers only need to perform a pressure test and then confirm the final installation.

[0004] This invention is achieved through the following technical solution:

[0005] A method for installing and positioning a radar level gauge for an LNG cargo tank includes the following steps:

[0006] Step S1: Orientation positioning. Based on the installation requirements of the shielding device and the direction of the waveguide bevel, determine the orientation of the shielding device and the adapter flange, and mark them accordingly.

[0007] Step S2: Flange welding. Assemble the tank flange. Use a spirit level and a level to measure and adjust the flange diameter from both the front and back and left and right directions to ensure the flange is level. After ensuring that the level requirement is met, complete the welding. After welding, re-measure using the same method.

[0008] Step S3: According to the direction markings on the adapter flange, install the adapter flange onto the tank flange and temporarily secure it with 4 bolts;

[0009] Step S4: Fabricate a laser positioning sleeve according to the actual dimensions of the radar mounting holes on the adapter flange and the laser instrument;

[0010] Step S5: Machining a pipe clamp positioning sleeve according to the actual outer diameter of the waveguide. The outer diameter of the positioning sleeve is consistent with the outer diameter of the waveguide, and a 3mm diameter through hole is machined in the center.

[0011] Step S6: Insert the laser positioning sleeve into the radar tube hole of the adapter flange, and then install the laser device onto the laser positioning sleeve and fix it with bolts.

[0012] Step S7, Radar Center Determination: Turn on the laser, adjust the beam size, and display a clear light spot on the bottom of the tank; attach a piece of white paper at the laser spot position; rotate the laser positioning sleeve and the laser instrument synchronously, and mark the laser spots displayed at 0°, 90°, 180°, and 270° on the white paper respectively; connect the four points at intervals, and the intersection of the lines is the theoretical center point;

[0013] Step S8: Adjust the laser so that the laser point hits the theoretical center point exactly; repeat step S7 to re-measure. The theoretical center drawn the second time should basically coincide with the theoretical center drawn the first time.

[0014] Step S9, Pipe clamp positioning: Clamp the pipe clamp positioning sleeve with the pipe clamp, and assemble the positioning pipe clamps one by one from bottom to top. The positioned pipe clamps need to be spot welded to fix them. When positioning the pipe clamps, the laser should be able to pass completely through the 3mm hole in the middle of the positioning sleeve.

[0015] Step S10: After the pipe clamp installation and welding are completed, a laser retest is performed. The laser should be able to pass through the center hole of all pipe clamp positioning sleeves and directly irradiate the theoretical center point at the bottom to ensure correct installation.

[0016] Step S11: Install the welded bottom plate. A level should be used to measure and position the plate to ensure it is level.

[0017] Step S12: Install the bottom shielding device according to the direction markings;

[0018] Step S13: Remove the laser device and temporary fixing bolts;

[0019] Step S14: Install the radar waveguide, tighten the flange bolts, pipe clamp bolts, etc., and install the bottom waveguide bevel after cutting the template according to the actual layout dimensions.

[0020] Furthermore, the radar level gauge mainly consists of a radar level gauge, an adapter flange, a tank flange, a radar waveguide, a fixed pipe clamp, a shielding device, and a base plate.

[0021] The beneficial effects of this invention are:

[0022] 1. Improve work efficiency.

[0023] 2. The center is determined by a rotating laser and a 4-point cross-positioning method. As long as it is within the laser range, any laser emitter can be used, and it is not affected by the accuracy of the laser.

[0024] 3. Laser positioning is used, ensuring precision and reliability. It is more accurate and less labor-intensive than using steel wires. Compared to physical assembly, it reduces the risk of damage to the waveguide and other components. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the radar level gauge structure according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the laser positioning sleeve structure according to an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the pipe clamp positioning sleeve structure according to an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of laser installation and center measurement according to an embodiment of the present invention.

[0029] In the attached diagram: 1-Radar level gauge; 11-Radar level meter; 12-Adaptor flange; 13-Tank flange; 14-Radar waveguide; 15-Fixing clamp; 16-Shielding device; 17-Base plate. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0031] It should be noted that all directional indicators (such as up, down, left, right, front, back, upper end, lower end, top, bottom, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0032] In this invention, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination should be considered non-existent and not within the scope of protection claimed by this invention.

[0034] A method for installing and positioning a radar level gauge for an LNG cargo tank includes the following steps:

[0035] Step S1: Orientation positioning. Based on the installation requirements of the shielding device and the direction of the waveguide bevel, determine the orientation of the shielding device and the adapter flange, and mark them accordingly.

[0036] Step S2: Flange welding. Assemble the tank flange. Use a spirit level and a level to measure and adjust the flange diameter from both the front and back and left and right directions to ensure the flange is level. After ensuring that the level requirement is met, complete the welding. After welding, re-measure using the same method.

[0037] Step S3: According to the direction markings on the adapter flange, install the adapter flange onto the tank flange and temporarily secure it with 4 bolts;

[0038] Step S4: Fabricate a laser positioning sleeve according to the actual dimensions of the radar mounting holes on the adaptable flange and the laser instrument; for example... Figure 2 As shown. The dimensions D1, D2, T, d1, and d2 of the laser positioning sleeve are configured according to the actual requirements of the laser instrument used, and the dimension D is configured according to the radar tube hole of the matching flange with a tolerance of +0.1 to +0.15 mm.

[0039] Step S5: Machining a positioning sleeve according to the actual outer diameter of the waveguide. The outer diameter of the positioning sleeve is consistent with the outer diameter of the waveguide, and a 3mm diameter through hole is machined in the center. Figure 3 As shown.

[0040] Step S6: Insert the laser positioning sleeve into the radar tube hole of the adapter flange, and then install the laser device onto the laser positioning sleeve and fix it with bolts.

[0041] Step S7, Radar Center Determination: Turn on the laser, adjust the beam size, and display a clear light spot on the bottom of the tank; place a piece of white paper at the laser spot location; rotate the laser positioning sleeve and laser instrument synchronously, marking the laser spots displayed at 0°, 90°, 180°, and 270° on the white paper respectively; connect the four points at intervals, and the intersection of the lines is the theoretical center point; refer to... Figure 4 .

[0042] Step S8: Adjust the laser so that the laser point hits the theoretical center point exactly; repeat step S7 to re-measure. The theoretical center drawn the second time should basically coincide with the theoretical center drawn the first time.

[0043] Step S9, Pipe clamp positioning: Clamp the pipe clamp positioning sleeve with the pipe clamp, and assemble the positioning pipe clamps one by one from bottom to top. The positioned pipe clamps need to be spot welded to fix them. When positioning the pipe clamps, the laser should be able to pass completely through the 3mm hole in the middle of the positioning sleeve.

[0044] Step S10: After the pipe clamp installation and welding are completed, a laser retest is performed. The laser should be able to pass through the center hole of all pipe clamp positioning sleeves and directly irradiate the theoretical center point at the bottom to ensure correct installation.

[0045] Step S11: Install the welded bottom plate. A level should be used to measure and position the plate to ensure it is level.

[0046] Step S12: Install the bottom shielding device according to the direction markings;

[0047] Step S13: Remove the laser device and temporary fixing bolts;

[0048] Step S14: Install the radar waveguide, tighten the flange bolts, pipe clamp bolts, etc., and install the bottom waveguide bevel after cutting the template according to the actual layout dimensions.

[0049] This invention uses a level to measure and adjust the flange diameter from both front, back, left, and right directions to ensure flange levelness. A laser positioning sleeve is machined and fitted to house the laser emitter. The center point is determined by rotating the laser device to 0°, 90°, 180°, and 270° and connecting the points. Pipe clamp positioning sleeves are machined for precise pipe clamp positioning, reducing errors from steel ruler measurements and accelerating installation. After installation, a laser re-measurement is performed to ensure the laser passes through the center holes of all positioning templates, guaranteeing correct installation.

[0050] Reference Figure 1 Specifically, in this embodiment, the radar level gauge 1 mainly consists of a radar level gauge 11, an adapter flange 12, a tank flange 13, a radar waveguide 14, a fixed pipe clamp 15, a shielding device 16, and a base plate 17.

[0051] Compared with existing technologies, the beneficial effects of this invention are as follows:

[0052] 1. Improve work efficiency.

[0053] 2. The center is determined by a rotating laser and a 4-point cross-positioning method. As long as it is within the laser range, any laser emitter can be used, and it is not affected by the accuracy of the laser.

[0054] 3. Laser positioning is used, ensuring precision and reliability. It is more accurate and less labor-intensive than using steel wires. Compared to physical assembly, it reduces the risk of damage to the waveguide and other components.

[0055] The technical solutions provided by the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the embodiments of the present invention. The descriptions of the embodiments above are only for helping to understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for installing and positioning a radar level gauge for an LNG cargo tank, characterized in that, Includes the following steps: Step S1: Orientation positioning. Based on the installation requirements of the shielding device and the direction of the waveguide bevel, determine the orientation of the shielding device and the adapter flange, and mark them accordingly. Step S2: Flange welding. Assemble the tank flange. Use a spirit level and a level to measure and adjust the flange diameter from both the front and back and left and right directions to ensure the flange is level. After ensuring that the level requirement is met, complete the welding. After welding, re-measure using the same method. Step S3: According to the direction markings on the adapter flange, install the adapter flange onto the tank flange and temporarily secure it with 4 bolts; Step S4: Fabricate a laser positioning sleeve according to the actual dimensions of the radar mounting holes on the adapter flange and the laser instrument; Step S5: Machining a pipe clamp positioning sleeve according to the actual outer diameter of the waveguide. The outer diameter of the positioning sleeve is consistent with the outer diameter of the waveguide, and a 3mm diameter through hole is machined in the center. Step S6: Insert the laser positioning sleeve into the radar tube hole of the adapter flange, and then install the laser device onto the laser positioning sleeve and fix it with bolts. Step S7, Radar Center Determination: Turn on the laser, adjust the beam size, and display a clear light spot on the bottom of the tank; attach a piece of white paper at the laser spot position; rotate the laser positioning sleeve and the laser instrument synchronously, and mark the laser spots displayed at 0°, 90°, 180°, and 270° on the white paper respectively; connect the four points at intervals, and the intersection of the lines is the theoretical center point; Step S8: Adjust the laser so that the laser point hits the theoretical center point exactly; repeat step S7 to re-measure. The theoretical center drawn the second time should basically coincide with the theoretical center drawn the first time. Step S9, Pipe clamp positioning: Clamp the pipe clamp positioning sleeve with the pipe clamp, and assemble the positioning pipe clamps one by one from bottom to top. The positioned pipe clamps need to be spot welded to fix them. When positioning the pipe clamps, the laser should be able to pass completely through the 3mm hole in the middle of the positioning sleeve. Step S10: After the pipe clamp installation and welding are completed, a laser retest is performed. The laser should be able to pass through the center hole of all pipe clamp positioning sleeves and directly irradiate the theoretical center point at the bottom to ensure correct installation. Step S11: Install the welded bottom plate. A level should be used to measure and position the plate to ensure it is level. Step S12: Install the bottom shielding device according to the direction markings; Step S13: Remove the laser device and temporary fixing bolts; Step S14: Install the radar waveguide, tighten the flange bolts and pipe clamp bolts, and install the bottom waveguide bevel after cutting the template according to the actual layout dimensions.

2. The method for installing and positioning a radar level gauge for an LNG cargo tank according to claim 1, characterized in that: The radar level gauge consists of a radar level gauge, an adapter flange, a tank flange, a radar waveguide, a fixed pipe clamp, a shielding device, and a base plate.

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