Insulation structure of lng carrier cargo tank and method for constructing the same

Abstract

An insulation structure of a cargo tank in an LNG carrier and a method of constructing the insulation structure includes a first metal foil attached and installed in between the top insulation panel and the bottom insulation panel, a second metal foil attached to and installed on the first metal foil that is positioned on an upper side of a gap formed between the bottom insulation panels, and a top bridge panel attached to and installed on an upper side of the second metal foil.

1 . An insulation structure of a cargo tank of an LNG carrier having a secondary barrier of a top insulation panel and bottom insulation panels, comprising:
 a first metal foil attached and installed in between the top insulation panel and the bottom insulation panels;   a second metal foil attached to and installed on the first metal foil at an upper side of a gap formed between the bottom insulation panels; and   a top bridge panel attached to and installed on an upper side of the second metal foil.   
     
     
         2 . The insulation structure of  claim 1 , wherein the first metal foil and the second metal foil are made of aluminum or stainless steel and are coated with a primer or silane. 
     
     
         3 . The insulation structure of  claim 1 , further comprising a protective films installed on adhesion parts formed on the first metal foil and the second metal foil and preventing a foreign substance from being attached. 
     
     
         4 . The insulation structure of  claim 1 , wherein adhesive members are pre-coated on adhesion parts formed on the first metal foil and the second metal foil, and the insulation structure further comprises protective films installed on the adhesive members and preventing a foreign substance from being attached. 
     
     
         5 . The insulation structure of  claim 4 , wherein the adhesive members comprises filler particles. 
     
     
         6 . The insulation structure of  claim 4 , wherein the adhesive members comprise an adhesive film in which an adhesive is coated on a surface of a synthetic resin film. 
     
     
         7 . The insulation structure of  claim 4 , wherein the adhesive members comprise a prepreg. 
     
     
         8 . The insulation structure of  claim 1 , wherein the second metal foil has a flat shape or a shape with an arc-shaped protruded groove in a middle area, the groove protruded downward along a lengthwise direction of the gap. 
     
     
         9 . A method of constructing an insulation structure of a cargo tank of an LNG carrier having a secondary barrier of a top insulation panel and bottom insulation panels comprising first metal foils attached and installed in between the top insulation panel and the bottom insulation panels, a second metal foil attached to and installed on the first metal foil at an upper side of a gap formed between the bottom insulation panels, and a top bridge panel attached to and installed on an upper side of the second metal foil, 
       the method comprising:
 attaching an adhesive film to a lower face of the second metal foil; 
 receiving the second metal foil at an adhesion location where the gap is covered in such a way that two opposite sides of the lower face of the second metal foil are respectively in contact with an adjacent pair of the first metal foils; 
 installing an adhesive jig on an upper face of the second metal foil; and 
 attaching the second metal foil to the first metals foil by heating and pressing the second metal foil with the adhesive jig. 
 
     
     
         10 . The method of  claim 9 , further comprising, prior to the attaching of the adhesive film, surface-treating a surface of the second metal foil. 
     
     
         11 . The method of  claim 10 , wherein the surface-treating is sand blasting or etching. 
     
     
         12 . The method of  claim 10 , further comprising, between the surface-treating of the surface of the second metal foil and the attaching of the adhesive film, coating a primer or silane on the surface of the second metal foil. 
     
     
         13 . The method of  claim 9 , wherein the adhesive jig comprises:
 pressing member configured to press the second metal foil downward; and   a heating pad installed in a lower part of the pressing member.   
     
     
         14 . The method of  claim 13 , wherein the pressing member includes an air bag. 
     
     
         15 . The method of  claim 13 , wherein the heating pad comprises a plane heater. 
     
     
         16 . The method of  claim 9 , wherein a width by which the first metal foils and the second metal foil make contact is between 70 mm and 90 mm. 
     
     
         17 . The method of  claim 9 , wherein the second metal foil is pressed to between 50 mbar and 350 mbar and heated to between 110° C. and 140° C. for 1 hour and 30 minutes to 2 hours by the adhesive jig. 
     
     
         18 . The method of  claim 17 , wherein the second metal foil is pressed to 300±1 mbar and heated to 130±1° C. by the adhesive jig. 
     
     
         19 . The method of  claim 15 , wherein a width and a length of the heating pad are respectively greater than those of the second metal foil. 
     
     
         20 . The method of  claim 19 , wherein the width and the length of the heating pad are greater than those of the second metal foil by 100 mm and 400 mm or more, respectively.