KR-102963299-B1 - HEAD PLATE FIT-UP DEVICE FOR LIQUEFIED GAS STORAGE TANK AND WELDING METHOD OF HEAD PLATE FOR LIQUEFIED GAS STORAGE TANK USING THE HEAD PLATE FIT-UP DEVICE

KR102963299B1KR 102963299 B1KR102963299 B1KR 102963299B1KR-102963299-B1

Abstract

The present invention relates to a mounting device for welding a liquefied gas storage tank end plate, which is divided into a dome-shaped crown portion and a plurality of knuckle portions having a predetermined curvature in the circumferential direction of the crown portion. The device comprises: a footrest structure having one or more layers and supporting the inner side of the plurality of knuckle portions; a pressurizing unit for pressing the outer surface of the knuckle portions; and a guide unit for supporting the pressurizing unit and simultaneously guiding the movement of the pressurizing unit in the circumferential direction of the end plate.

Inventors

곽명섭

Assignees

한화오션 주식회사

Dates

Publication Date: 20260511
Application Date: 20210712

Claims (13)

A mounting device for welding end plates of a liquefied gas storage tank, which is divided and formed into a dome-shaped crown portion and a plurality of knuckle portions having a predetermined curvature in the circumferential direction of the crown portion, A footrest structure having one or more layers and supporting the inner side of the plurality of knuckle parts; A pressure unit for pressing the outer surface of the above-mentioned knuckle portion; and A mounting device for a liquefied gas storage tank end plate, comprising a guide unit for supporting the above-mentioned pressurizing unit and simultaneously guiding the movement of the above-mentioned pressurizing unit in the circumferential direction of the end plate.
In Article 1, A mounting device for a liquefied gas storage tank, wherein the edge end of each layer of the above-described foot structure is configured to be adjustable in length in a direction toward the inner surface of the knuckle portion corresponding to the diameter of the above-described end plate.
In Article 1, The above guide unit is, A ring-shaped base frame arranged to surround the above-mentioned footrest structure; A support frame positioned on the base frame and supporting the pressurizing unit; and A mounting device for a liquefied gas storage tank, comprising a driving unit for rotating the support frame in the circumferential direction of the base frame.
In Paragraph 3, The above driving unit is, A driving motor installed on one side of either the base frame or the support frame; A pinion gear coupled to the drive shaft of the above-mentioned drive motor; and A mounting device for a liquefied gas storage tank comprising a rack installed on one side of the base frame and the other of the support frame so as to mesh with the pinion gear.
In Paragraph 4, The support frame has a ring shape to surround the footrest structure, and The above-mentioned drive motor is installed at a point on the inner circumference of the base frame and is configured so that the drive shaft faces upward. The above rack is a mounting device for the end plate of a liquefied gas storage tank installed on the inner circumference of the support frame so as to mesh with the above pinion gear.
In Paragraph 3, The above guide unit is, A mounting device for a liquefied gas storage tank, further comprising a plurality of frame support members provided between the base frame and the support frame.
In Paragraph 3, The above-mentioned pressurizing unit is, A pressure roller section equipped with one or more rollers that rotate in close contact with the outer surface of the above-mentioned knuckle section; A lifting cylinder connected to the above-mentioned pressure roller part for adjusting the height of the above-mentioned pressure roller part; and A mounting device for a liquefied gas storage tank, comprising an angle adjustment unit connected to one side in the longitudinal direction of the lifting cylinder unit to adjust the rotation angle of the lifting cylinder unit.
In Article 7, The above lifting cylinder part is, A mounting device for a liquefied gas storage tank, hinged to the above support frame and configured to rotate in the forward and backward directions.
In Paragraph 8, The above angle adjustment unit is, A mounting device for a liquefied gas storage tank, wherein the other end is hinge-connected to the support frame at a position spaced apart from the lifting cylinder.
In Article 9, The above lifting cylinder section and the above angle adjustment section comprise a multi-stage hydraulic cylinder that extends and retracts in the longitudinal direction, forming a mounting device for the end plate of a liquefied gas storage tank.
In Article 10, The above-mentioned pressure roller part is, A mounting device for a liquefied gas storage tank, further comprising a roller support that is extended from the upper end of the lifting cylinder portion toward the knuckle portion and supports the rotation axis of the roller.
In Paragraph 11, The above-mentioned pressure roller section is a pair of knuckle sections positioned respectively on two adjacent knuckle sections among a plurality of knuckle sections, forming a mounting device for the end plate of a liquefied gas storage tank.
A welding method for a head plate formed by dividing it into a dome-shaped crown portion and a plurality of knuckle portions having a predetermined curvature in the circumferential direction of the crown portion, A knuckle tack welding step in which the plurality of knuckle portions are arranged adjacent to each other in the circumferential direction of the above-mentioned end plate and tack welded along a weld seam formed by the edges of the plurality of knuckle portions coming into contact with each other; It includes a head plate main welding step in which the edge of the crown portion is positioned to come into contact with the upper end of the plurality of tack-welded knuckle portions, and main welding is performed on the plurality of tack-welded knuckle portions and the crown portion. In the above knuckle tack welding step, A method for welding end plates of a liquefied gas storage tank, using a mounting device according to claim 1 to support the inner side of the plurality of knuckle parts and simultaneously press another knuckle part adjacent to one of the plurality of knuckle parts from the outside.

Description

Head Plate Fit-Up Device for Liquefied Gas Storage Tank and Welding Method of Head Plate for Liquefied Gas Storage Tank Using the Head Plate Fit-Up Device The present invention relates to a method for manufacturing a liquefied gas storage tank, and more specifically, to a head plate mounting device for a liquefied gas storage tank for welding a head plate which is coupled to both ends in the longitudinal direction of a shell body having a hollow cylinder shape and is divided into a dome-shaped crown portion and a plurality of knuckle portions having a predetermined curvature in the circumferential direction of the crown portion, and a method for welding a head plate of a liquefied gas storage tank using the head plate mounting device. The International Maritime Organization (IMO) regulates the emission of nitrogen oxides (NOx) and sulfur oxides (SOx) from ships to prevent air pollution. Since 2020, it has been implementing environmental regulations to reduce the sulfur content of ship fuel oil from the existing 3.5% to 0.5%, leading to an increase in orders for LNG-fueled ships (LFS). Recently, there has been an increasing demand for LFS fueled by LNG, an eco-friendly fuel, for a wider variety of ship types, including not only LNG carriers that transport LNG as cargo but also container ships and tankers. By obtaining official certification from classification societies in various countries, it is meeting the demand for transition to eco-friendly energy due to environmental regulations. Engines capable of using natural gas such as LNG as fuel in these vessels include ME-GI (Main engine Electronic control Gas Injection) engines and DFDE (Dual Fuel Diesel Electric) engines. The ME-GI engine consists of two strokes and adopts a diesel cycle that injects high-pressure natural gas at around 300 bar directly into the combustion chamber near the top dead center of the piston. The DFDE engine consists of four strokes and adopts the Otto cycle, in which natural gas with a relatively low pressure of about 6.5 bar or 18 bar is injected into the combustion air inlet and compressed as the piston rises. In the case of DFDE engines following the Otto cycle, fuel efficiency may be lower compared to ME-GI engines following the diesel cycle, but there is an advantage that the amount of nitrogen oxides produced during combustion is low because the combustion temperature of the fuel is not high. Meanwhile, since natural gas is in a gaseous state at room temperature and pressure and has a very large volume, there are severe space constraints for storage. Therefore, by utilizing the characteristic of maintaining a liquid state at an extremely low temperature of approximately -163°C at normal atmospheric pressure, cryogenic LNG can be stored in a liquid state at atmospheric pressure in a special storage tank treated with insulation. These storage tanks can be classified into membrane type and independent type depending on whether the load of the cargo acts directly on the insulation material; membrane type storage tanks are divided into No. 96 and Mark III types, and independent type storage tanks can be divided into Type A, Type B, and Type C according to the regulations of the International Maritime Organization. Type A storage tanks have a primary barrier and a secondary barrier that completely surrounds it to prevent a large-scale leak of liquefied gas, and Type B storage tanks have a partial secondary barrier structure to safely collect leaked liquefied gas in accordance with the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC code). Type C storage tanks are pressure vessels that have only a primary barrier, ensuring safety and reliability so that a secondary barrier is not required. They have the advantage of shortening construction time because they are manufactured externally and then installed on the ship, and they are separated from the ship's inner hull, making maintenance easier. The aforementioned technical configuration is provided as background technology to aid in understanding the present invention and does not constitute prior art widely known in the technical field to which the present invention belongs. Figure 1 is a schematic diagram illustrating a typical liquefied gas storage tank. FIG. 2 is a block diagram showing a method for manufacturing a liquefied gas storage tank according to one embodiment of the present invention. FIG. 3 is a block diagram illustrating the manufacturing process of a shell body in a method for manufacturing a liquefied gas storage tank according to one embodiment of the present invention. FIG. 4 is a block diagram illustrating a method for welding end plates of a liquefied gas storage tank according to one embodiment of the present invention. FIG. 5 is a schematic diagram illustrating the configuration of a end plate mounting device for a liquefied gas storage tank according to one embodiment of the present invention. FIG. 6 is a s