An isolation tool for LNG liquid cargo tank body pipeline interface and construction method

Abstract

The application relates to the technical field of pipeline construction, and discloses an isolation tool for an LNG liquid cargo tank body pipeline interface and a construction method. The construction tool comprises an expansion part, an inflation part, a connecting pipe and a one-way air release valve. The outer diameter of the expansion part is smaller than the inner diameter of the inlet pipeline in the initial state, and the maximum outer diameter of the expansion part is larger than the inner diameter of the modified pipeline after expansion. The inflation part is used for inflating the expansion part. The expansion part and the inflation part are communicated through the connecting pipe. The one-way air release valve is arranged on the connecting pipe. The expansion part collects and cleans the sundries generated in the pipeline modification process, effectively avoids the sundries from falling into the liquid cargo tank and causing damage to the liquid cargo tank, the construction tool has a simple structure, low procurement and manufacturing costs, is truly low-cost and high-return, greatly improves the construction efficiency, and saves the construction cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pipeline construction, in particular to a separation tool for LNG liquid cargo tank pipeline interface and a construction method. BACKGROUND

[0002] The working condition of an LNG ship is very harsh. It is a ship specially used for storing and transporting liquefied gas at a low temperature of-163 DEG C, commonly known as "super cold car on the sea". The core of LNG equipment is the LNG storage tank liquid cabin, which generally includes an inner container, an outer shell, a pipeline system, etc., and has a complex structure and extremely high requirements for design and manufacturing. Since it is a cabin for storing low-temperature products and a pressure vessel, every step of the process must be strictly inspected, and the process requirements are very high and the inspection is very strict. During the operation of the ship, the liquid cargo cabin interface pipeline may need to be modified for some reason. Since the liquid cargo cabin interface pipeline is connected to the liquid cargo cabin, sparks and welding slag will inevitably be generated during the modification and construction of the liquid cargo cabin interface pipeline. When the high-temperature sparks and welding slag fall into the liquid cargo cabin, they will cause serious damage to the special metal of the liquid cargo cabin wall. It will take a lot of time and cost to repair the damaged cabin wall and report. SUMMARY

[0003] The purpose of the present application is to provide a separation tool for LNG liquid cargo tank pipeline interface and a method of application. The tool can isolate and seal the modified pipeline, and can avoid the situation that sparks and welding slag fall into the liquid cargo cabin and cause damage to the liquid cargo cabin.

[0004] In order to achieve the above-mentioned purpose, in one aspect, the present application provides a separation tool for LNG liquid cargo tank pipeline interface, comprising:

[0005] An expansion part, the outer diameter of which in the initial state is smaller than the inner diameter of the inlet pipeline, and the maximum outer diameter of which after expansion is greater than the inner diameter of the modified pipeline;

[0006] An inflation part, used for inflating the expansion part;

[0007] A connecting pipe, through which the expansion part and the inflation part are communicated;

[0008] A one-way air release valve, provided on the connecting pipe.

[0009] Preferably, a separation skirt is provided on the side of the expansion part.

[0010] Preferably, the expansion part is an expansion air bag, and the inflation part is a hand-held inflation air bag.

[0011] Preferably, the expansion air bag and the hand-held inflation air bag are both made of high-temperature resistant and heat resistant rubber material.

[0012] Preferably, the connecting pipe is detachably connected with the inflation part.

[0013] In another aspect, the application provides a method for constructing the isolation tool, comprising:

[0014] extending the inflation part into the modified pipeline below the weld;

[0015] inflating the inflation part through the inflation part to make the inflation part adhere to the inner wall of the modified pipeline;

[0016] cutting along the weld using a cutting tool and removing the cut part out of the isolation tool;

[0017] positioning and assembling a new interface pipeline and welding the new interface pipeline with the weld of the modified pipeline;

[0018] removing the debris falling on the inflation part and taking out the isolation tool.

[0019] Preferably, the distance between the inflation part and the weld of the modified pipeline is greater than or equal to 100 mm.

[0020] Preferably, after the step of cutting along the weld using a cutting tool and removing the cut part out of the isolation tool, the method further comprises:

[0021] polishing and chamfering the cut part.

[0022] Preferably, after the step of polishing and chamfering the cut part, the method further comprises:

[0023] removing the debris falling on the inflation part.

[0024] Preferably, the method further comprises performing non-destructive testing on the new weld of the modified pipeline according to inspection requirements.

[0025] By the above technical solution, the debris generated during the pipeline modification process is collected and cleaned by the inflation part, effectively avoiding the situation that the debris falls into the liquid cargo tank and causes damage to the liquid cargo tank. The construction tool has a simple structure, low procurement and manufacturing cost, and truly low cost and high return, greatly improving the construction efficiency and saving the construction cost.

[0026] Other features and advantages of the application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, and are used together with the following specific embodiments to explain the application, but do not constitute a limitation on the application. In the drawings:

[0028] Figure 1 A structural diagram of the construction tool of the present application is shown;

[0029] Figure 2 A modification comparison diagram of the liquid cargo tank inlet pipe of the embodiment of the present application is shown;

[0030] Figure 3 An installation diagram of the construction tool of the embodiment of the present application is shown;

[0031] Figure 4 A debris removal diagram after pipe cutting of the embodiment of the present application is shown;

[0032] Figure 5 A new interface pipe installation diagram of the embodiment of the present application is shown;

[0033] Figure 6 A debris removal diagram after the new interface pipe installation of the embodiment of the present application is shown. DETAILED DESCRIPTION

[0034] The specific embodiments of the present application are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application.

[0035] Example 1

[0036] In this embodiment, since the GCU is installed and the liquid cargo tank inlet pipe is modified, the inlet pipe needs to be changed from an elbow to a tee, the elbow needs to be cut off, and then a new interface pipe, i.e. a tee pipe, is installed.

[0037] Please refer to Figure 1 In one aspect, the present embodiment provides an isolation tool for LNG liquid cargo tank body pipe interface, which comprises an expansion part 1, an inflation part 2, a connecting pipe 3, and a one-way air release valve 4.

[0038] The expansion part 1 is specifically selected from an expansion air bag made of high-temperature-resistant and heat-resistant rubber, which is used to isolate the liquid cargo tank interface pipe from the liquid cargo tank. In order to ensure the feasibility of the operation and the sealing isolation effect, the expansion air bag size needs to be designed according to the actual modified pipe, and the outer diameter of the expansion air bag under normal circumstances needs to be smaller than the inner diameter of the modified pipe, and the maximum outer diameter after inflation needs to be greater than the inner diameter of the modified pipe. In order to make the expansion part 1 better receive the debris, such as iron filings and welding slag, falling during the modification process, a skirt 5 is arranged on the side of the expansion part 1. The expansion air bag is circular after being filled with air, and the skirt 5 can well fill the gap left above between the modified pipe and the expansion air bag (see Figure 3 ), thereby forming a receiving surface in the shape of a swallowtail. In addition, a plurality of anti-skid lines can be arranged on the sidewall of the expansion air bag, which can increase the friction between the expansion air bag and the sidewall of the modified pipe, and avoid the expansion air bag from sliding down due to excessive load.

[0039] Please refer to Figure 2 and Figure 3 In this embodiment, since the elbow is a reducing pipe, the inner diameter of the modified pipeline gradually increases from the inlet, and the outer diameter of the inflatable air bag before inflation needs to be smaller than the inner diameter of the inlet pipe section A, and the maximum outer diameter after inflation should be greater than the inner diameter of the inlet pipe section B.

[0040] The inflation part 2 can be a hand-knitting inflatable air bag made of high-temperature-resistant and heat-resistant rubber, which is used to inflate the expansion part 1. The hand-knitting inflatable air bag is a common inflatable air bag in the prior art that can achieve free inflation and deflation, and will not be described here.

[0041] The connecting pipe 3 is a hose, and the expansion part 1 and the inflation part 2 are connected through the connecting pipe 3. The length of the connecting pipe 3 is reserved with sufficient margin according to the actual length of the modified pipeline, which is more convenient during operation. Further, in order to facilitate operation, the connecting pipe 3 and the inflation part 2 are detachably connected, so that after the expansion part 1 is fully inflated, the inflation part 2 is removed for subsequent operation. Specifically, the connection can be made through a quick connector. In this case, the inflation part 2 can be inflated using an inflator, which is faster.

[0042] Furthermore, the expansion part 1 and the connecting pipe 3 can also be detachably connected, and the connection method is the same as the above connection method, so that different sizes of inflatable air bags can be replaced according to different modified pipelines, without the need to replace the entire tooling, thereby improving the practicality of the tooling.

[0043] The one-way air release valve 4 is provided on the connecting pipe 3. In the normal state, air can enter the inflatable air bag from the inflation air bag, but cannot flow out of the inflatable air bag. When deflation is needed, the one-way air release valve 4 can be opened to allow air in the inflatable air bag to flow out.

[0044] Application Example

[0045] The present embodiment provides a construction method of the above isolation tooling, which comprises:

[0046] S1: preparation and confirmation work before construction.

[0047] Confirm the modification scheme, prepare several saw blades for cutting the pipe section, a small vacuum cleaner, a sander, a welding machine that meets the welding requirements of the modified pipeline WPS, and the above construction tooling.

[0048] S2: Implementation steps of the liquid cargo tank interface pipe section modification tooling scheme

[0049] a: The inflatable air bag of the construction tooling is inserted along the flange of the liquid cargo tank inlet pipe section A in the Figure 3 until the inflatable air bag is located at a distance of Figure 3The middle of the pipe weld is not less than 100mm below the straight pipe section.

[0050] b: press the inflatable air bag to inflate the air bag until it is inflated to tightly fit the inner wall of the modified pipeline.

[0051] c: use a saw blade to saw off the connection between the concentric reducer and the straight pipe section at the original ship weld in Figure 3 . Move the sawed-off elbow, concentric reducer and flange aside. When moving the sawed-off elbow and concentric reducer, be careful not to damage the connecting pipe 3 and the inflatable air bag to cause the inflatable air bag to leak. (The inflatable air bag remains in the pipe). When the connecting pipe 3 and the inflatable air bag are detachably connected, the inflatable air bag can be detached after being inflated, and then the sawed-off material is pulled out along the connecting pipe 3, which is more convenient to operate.

[0052] d: according to the requirements of WPS, use a grinder to grind and chamfer the sawed weld.

[0053] e: after grinding and chamfering, use a small vacuum cleaner to remove iron filings, welding slag and debris. (see Figure 4 ) (Carefully check to ensure that the welding slag, iron filings and debris are completely removed).

[0054] f: after removing the impurities with the vacuum cleaner, open the one-way air release valve to slowly release the air in the inflatable air bag, and take out the inflatable air bag. (Before pulling out the inflatable air bag from the pipe, the air valve should be opened to release the air in the inflatable air bag to keep it at the normal size without inflation, so as not to damage the inflatable air bag).

[0055] g: assemble and position the new tee.

[0056] h: put the inflatable air bag into the same or similar position mentioned in step a along the upper opening of the assembled tee, (as shown in Figure 5 ) and then press the inflatable air bag to inflate the air bag until it is inflated to tightly fit the inner wall of the modified pipeline.

[0057] i: pass argon gas and weld according to the requirements of WPS. (During welding, strictly follow the requirements of WPS for argon gas passing and welding construction).

[0058] j: after welding, use a small vacuum cleaner to clean and remove the impurities in the pipe. (see Figure 6 ) (Carefully check to ensure that the welding slag, iron filings and debris are completely removed).

[0059] k: open the air release valve to release the air in the inflatable air bag and take out the inflatable air bag.

[0060] l: perform non-destructive testing on the welds of the modified pipeline according to the inspection requirements to ensure the quality of the welds.

[0061] Through the technical scheme, the sundries generated in the pipeline modification process are collected and cleaned by the expansion part 1, the situation that the sundries fall into the liquid cargo tank to cause damage to the liquid cargo tank is effectively avoided, the construction tool structure is simple, the purchase and manufacturing cost is low, the true low-cost high return is realized, the construction efficiency is greatly improved, and the construction cost is saved.

[0062] The preferred embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application. In addition, it should be noted that, in the above-described specific embodiments, various specific technical features can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present application will not further describe various possible combination manners.

[0063] In addition, various different embodiments of the present application can also be combined in any manner, as long as they do not deviate from the idea of the present application, and they should also be considered as disclosed content of the present application.

Claims

1. An isolation tool for LNG liquid cargo tank vessel piping interface, characterized in that, The utility model relates to a kind of welding joint modification tooling, including: Expansion part, the outer diameter of initial state, it is less than the inner diameter of inlet pipeline, after expansion, its maximum outer diameter is greater than the inner diameter of modified pipeline; Inflatable part, the inflatable part is used to inflate the expansion part; Connecting pipe, the expansion part and inflatable part are communicated by the connecting pipe; One-way air release valve, the one-way air release valve is arranged on the connecting pipe; The expansion part is inflatable bag, and the inflatable part is hand-kneading inflatable bag;The side of the expansion part is provided with isolation skirt;Inflatable bag is full of gas after being circular, and the gap left above between isolation skirt and inflatable bag is filled, to form a receiving surface similar to swallow-tail shape;Multiple anti-skid lines are further provided on the sidewall of the inflatable bag.

2. The insulation tool for LNG cargo tank piping interface according to claim 1, characterized in that, The expansion part and the inflatable part are made of high-temperature-resistant and heat-resistant rubber material.

3. The insulation tool for LNG cargo tank piping interface according to claim 1, characterized in that, The connecting pipe and the inflatable part are detachably connected.

4. A method of applying an isolation kit as claimed in any one of claims 1 to 3, characterised in that, Including: The expansion part is inserted into the modified pipeline below the weld seam; The inflatable part is inflated to the expansion part by the inflatable part to adhere to the inner wall of the modified pipeline; Cutting tool is used to cut along the weld seam, and the cut part is removed from the isolation tooling;The cutting part is polished and chamfered, and the debris falling on the expansion part is removed; New interface pipeline is assembled and positioned, and welded with the weld seam of the modified pipeline; The debris falling on the expansion part is removed, and the isolation tooling is taken out; According to the inspection requirement, the new weld of the modified pipeline is nondestructively tested.

5. The method of installing an isolation kit of claim 4, wherein, The distance between the expansion part and the weld seam of the modified pipeline is greater than or equal to 100 mm.

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