KR102139503B1 - A method for insulation construction of liquified gas tank - Google Patents

Abstract

The present invention relates to a method for insulation construction of a liquefied gas tank, which performs an insulation construction on an external surface of the tank through a urethane foam spray, and promotes the integration of the external surface of the urethane foam with the internal surface of a metal plate in the construction process for covering the external surface of the urethane foam with the metal plate, thereby improving reliability of the insulation construction. According to the present invention, the method for insulation construction of a liquefied gas tank comprises: a step (S1) of evenly coupling base rods (210) to the external surface of the tank (100) in a vertical direction; a step (S2) of forming a plurality of lower insulation layers (300) on the external surface of the tank without covering an upper end of the base rods (210); a step (S3) of connecting a lower end of an extension rod (230) to an upper end of the base rods (210) for extending the length of the base rods (210); a step (S4) of forming an insulation foam on an upper surface of the lower insulation layer (300) by a foam free spray method to form an additional plurality of upper insulation layers (400); a step (S5) of placing metal plates (600) having through holes to be penetrated by the extension rod (230) at a certain interval from an upper surface of the upper insulation layer (400); a step (S6) of performing an injection towards a side of an interval space between the upper insulation layer and the metal plate by the foam free spray method to form an uppermost insulation foam layer by using polyurethane; a step (S7) of separating the extension rod (230) from the base rods (210); and a step (S8) of additionally injecting insulation foam into the space, from which the extension rod (230) is removed, by foam free spray to fill the space.

Description

Insulation method for liquefied gas tanks {A METHOD FOR INSULATION CONSTRUCTION OF LIQUIFIED GAS TANK}

The present invention relates to a construction method of a liquefied gas tank, and the outer surface of the tank is insulated through the urethane foam spray, and the outer surface of the urethane foam and the inner surface of the metal plate are integrated in the construction process of covering the outer surface of the urethane foam with a metal plate. It relates to a method of adiabatic construction of a liquefied gas tank that can improve the reliability of the adiabatic construction.

At present, there are two types of thermal insulation construction methods that are widely used in the construction and shipbuilding industries: the urethane foam is attached in a panel form and the urethane foam is sprayed. In particular, in shipbuilding industry, these two methods are used for the insulation method of LNG carriers classified as special vessels and LPG vessels.However, the method of attaching foam panels to tanks of LNG carriers storing -150 degree fuel is widely used. In addition, a foam spray method is applied to the tank of the LPG ship that stores -50 degrees of fuel.

On the other hand, urethane foam has the disadvantage of being easily damaged because it is easily corroded by ultraviolet rays (UV), and must be completed by adhering to the outer surface of the urethane foam using a finishing material to protect the foam surface.

The panel-type insulation used for tank insulation of LNG carriers is usually made of a urethane foam finishing material integrally with the urethane foam, which is manufactured and transported at the factory to be attached to the outer surface of the tank. This is because the finished panel is used, so there is no need for a separate finishing work, but the size of the finished panel is large and heavy, so the work is not easy, so the construction period is long and the cost of insulation increases.

On the other hand, there is a method of applying a urethane foam to the outer surface of the storage tank by applying a foam-free spray method to the insulation tank and completing the foam surface, that is, a separate finishing process, that is, applying FRP by applying urea of a resin type, but liquefied LNG fuel tank. When applied to FRP, the commonly used FRP is brittle in a low temperature environment and has a problem of easy breakage, and the metal plate or tin of steel material is the best choice, but the metal plate is not easily attached to the surface of the insulating foam. There is a problem with attaching.

In particular, as LNG engines are used as propulsion fuel for LNG carriers or LPG vessels in recent years, demand for small LNG fuel storage tanks that supply LNG fuel to LNG carriers is increasing. An economical and easy construction method for insulating a fuel tank of a small LNG carrier is required. The small LNG fuel tank is a cryogenic tank, but because it is small, it provides sufficient thermal insulation performance even with thermal insulation using a foam-free spray method. However, attempts have been made to apply thermal insulation of the foam-free spray method, but after the foam-free spray construction, In attaching the finishing material that protects the surface, it is confronted with the brittleness of FRP and the adhesion problem of steel materials.

Accordingly, the inventor of the present invention has devised a method for insulating a storage tank for a small LNG carrier capable of solving such a problem.

Prior Literature: Korean Patent Registration No. 10-1159175 (Registered on June 18, 2012)

An object of the present invention is to provide an insulating construction method of a liquefied gas tank that enables economical and easy adhesion of a urethane foam and a metal plate finishing material so that a metal plate can be used as a finishing material while insulating the outer circumferential surface of the tank with a urethane foam. do.

The present invention is to form a heat insulating layer and a metal plate finish by a support rod consisting of a base rod formed perpendicular to the outer circumferential surface of the tank and an extension rod detachably coupled from the top of the base rod.

In addition, the present invention is to apply a polyurethane foam to the outer circumferential surface of the tank by a foam-free spray method or to form a plurality of insulating layers by laminating a polyurethane insulating panel, after placing a metal plate spaced a predetermined distance from the top surface of the insulating layer and then the metal plate and the insulating layer By filling the polyurethane foam by injection with a foam-free spray method between the upper surfaces, the polyurethane foam is bonded between the metal plate and the upper surface of the upper insulating layer, and after removing the extension bar from the base bar, the polyurethane foam is additionally injected into the empty space. Filling completes the insulation.

The present invention considers that it is difficult to separately adhere the metal plate which is the finishing material after applying the insulating foam by the foam-free spraying method, and after the metal plate is installed after the metal plate is placed with the spaced apart on the upper surface of the upper insulating layer attached to the outer surface of the fuel tank. When a separate insulating foam spray is injected between spaces, adhesion of the sprayed insulating foam between the upper insulating layer and the metal plate is completely made, so that the metal plate can be easily attached to the upper surface of the upper insulating layer as a finishing material.

1 and 2 are views showing a construction method of the first embodiment according to the present invention
3 and 4 are views showing a construction method of the second embodiment according to the present invention
5 and 6 are views showing a construction method of the third embodiment for the repair construction of the existing insulation tank
7 is a cross-sectional view of the basic rod and the extension rod directly connected according to the present invention
8 is a view showing that a wooden plate is added to the top of the metal plate

The method for insulating a liquefied gas tank of the present invention will be described based on the first embodiment of FIGS. 1 and 2.

(1) step (S1) of evenly coupling the base rod 210 evenly to the outer surface of the tank 100;

-In order to evenly fix the base rod 210 to the outer surface of the tank 100, a welding or fastening method may be used. Preferably, the washer portion having a large area is fixed to the outer surface of the tank by welding on a T-shaped base rod 210 having a wide bottom surface and a vertical rod connected upward from the bottom surface.

(2) Next, forming a plurality of lower insulating layers 300 on the outer surface of the tank so that the base rod 210 is not covered (S2);

-The lower insulating layer 300 is preferably formed of a polyurethane insulating foam layer using a foam-free spray, but can be selectively replaced with a polyurethane insulating panel. However, when using a polyurethane insulation panel, there is a disadvantage that it is very cumbersome in transportation and work, such as the need to use a crane because the size is very large.

-The polyurethane insulating foam layer formed by foam-free spray has a height of about 3 cm at a time. Therefore, the number of layers of the insulating foam layer is determined according to the height of the base rod 210. At least 10 foam-free spray insulation works are required to perform a total of 40cm height insulation work. When a plurality of insulating foam layers are formed, adhesion between the insulating foam layers is strengthened by interposing a mesh 310 made of glass fibers between the insulating foam layers of each layer.

(3) connecting the lower end of the extension rod 230 to the upper end of the vertical rod 210 so as to extend the length of the base rod 210 (S3);

-It is possible to directly connect the base rod 210 and the extension rod 230. At this time, the upper end of the base rod and the lower end of the extension rod are combined to be separated from each other. The base rod 210 and the extension rod 230 may be directly connected as shown in FIG. 7, but preferably the washer connecting member (between the base rod 210 and the extension rod 230 as shown in FIGS. 2 and 4) 220) and are connected to each other by the connecting member 220. Specifically, a female screw portion 221a is formed at a lower portion of the connecting member 220 as a washer portion 221 and coupled with a male screw portion 211 provided at an upper portion of the base rod. An upper portion of the washer portion 221 of the connection member 220 is provided with a coupling portion 222 so as to be detachable from the lower portion of the extension rod 230.

The lower portion of the connecting member 220 is provided with a washer portion 221, and an upper portion is provided with a coupling portion 222. The connecting member is interposed between the upper insulating layer 300 and the lower insulating layer 400 and fixed, so that after construction is completed, shrinkage occurs by the cryogenic liquefied gas tank, and at this time, it serves to prevent deformation due to shrinkage. That is, the upper and lower surfaces of the washer portion of the washer connecting member are adhered to the lower insulating layer and the upper insulating layer to prevent warping and damage of the insulating panel or insulating foam due to shrinkage stress.

(4) forming an additional plurality of upper insulating layers 400 by applying a foam-free spray method on the upper surfaces of the lower insulating layers 300 (S4);

-The upper insulating layer 400 is preferably formed of a polyurethane insulating foam layer using a foam-free spray, as in the lower insulating layer 300, but can be selectively replaced with a polyurethane insulating panel. In addition, preferably, the adhesive strength is increased by interposing a glass fiber mesh between the lower insulating layer or the upper insulating layer.

(5) disposing a metal plate having a through hole to penetrate the extension rod 230 at a predetermined distance from the upper surface of the upper insulating layer 400 (S5);

-Various methods of arranging the upper insulating layer 400 and the metal plate in a spaced apart state are possible. For example, by separating the insulating block 620 having a predetermined thickness on the upper insulating layer 400 and placing the metal plate 600 to be supported on the insulating block 620, the space between the upper insulating layer and the metal plate ( 630). Preferably, the upper end of the extension rod 230 protruding through the through-hole of the metal plate 600 is fixed by a coupling member 240, but the upper end of the extension rod 230 is formed with a male thread, and is coupled The member 240 is formed with a female thread at the lower end and is fastened to the extension rod 230. In step S5, the wooden plate 800 is preferably added to the upper surface of the metal plate 600 to prevent the metal plate from swelling.

(6) forming an uppermost insulating foam layer 500 with polyurethane by injecting in a form-free spray manner to the side of the space between the upper insulating layer 400 and the metal plate 600 (S6);

-In order to form the uppermost insulating foam layer 500, a polyurethane insulating foam is injected and filled to form the uppermost insulating foam layer 500 in a space between the upper insulating foam layer and the metal plate. The insulation foam injected through the injection of the insulation foam is integrated by being simultaneously coupled to the surface of the lower upper insulating layer 400 and the surface of the metal plate 600.

(7) separating the extension rod 230 from the base rod 210 (S7);

-When the extension rod 220 is separated from the base rod 210, the remaining space exists after the extension rod is separated from the top insulation foam layer and the top insulation foam layer. If the extension rod is left unremoved, heat is transferred through the base rod and the extension rod, so that the cold air of the low temperature liquefied gas tank cannot be maintained. When the through hole of the metal plate is installed through the extension rod 230 and the coupling member 240 is coupled, the coupling member 240 must be separated together with the extension rod 230. If a connecting member is interposed between the extension rod 230 and the base rod 210, the extension rod 230 is separated from the connection member 220.

(8) forming a polyurethane insulating foam by additional injection and filling in the space where the extension rod is removed (S8);

-If the space where the extension rod is removed is left, the thermal insulation performance decreases through this, and thus the insulation performance is additionally reinforced by additionally injecting and filling a polyurethane insulation foam in the space where the extension rod 230 is removed.

In forming a plurality of lower insulating layers, it can be easily replaced by laminating a polyurethane panel as in the second embodiment of FIGS. 3 and 4 without applying a foam-free spray method. The second embodiment in which the construction method is indicated in steps (A) to (H) has the same ultimate and problem solving principle as the first embodiment.

The lower insulating layer and the upper insulating layer are formed by the above method, and an additional uppermost insulating foam layer is formed to bond between the metal plate and the upper insulating layer. Here, the lower insulating layer and the upper insulating layer are classified based on the base rod and the extension rod. That is, the lower insulating layer is formed around the base rod, and the upper insulating layer is formed around the extension rod. However, as a method of forming the lower insulating layer, it is preferable to form a polyurethane insulating foam by foam-free spraying, but it is also possible to use a polyurethane insulating panel.

On the other hand, when the repair, such as replacing the finishing material of the insulation tank using the existing FRP finishing material with a metal plate, proposes a third embodiment as shown in Figures 5 and 6.

That is, in the method of insulating the liquefied gas tank to repair the finishing material provided on the upper surface of the insulating layer formed on the outer surface of the tank 100,

(A) removing the finishing material covered on the top of the heat insulating layer (P1);

-Existing liquefied gas insulation tanks are used to form an insulation layer using an insulation panel or insulation foam, and often use FRP as a finishing material on the outer surface.

A case in which a finishing material must be newly formed on the upper surface of the heat insulating layer using a metal plate occurs, and in such a case, the maintenance work starts from removing the previously provided finishing material.

(b) forming a through hole to the outer surface of the tank at a predetermined interval in the heat insulating layer, inserting a base rod 210 into the through hole, and then additionally injecting and filling the heat insulating foam by a foam-free spray method (P2);

-Existing insulation layer is not removed, but a through hole is formed at a predetermined interval on the insulation layer to form a base rod to the bottom of the tank, and an insulating foam is filled between the through hole and the base rod by injection to fix the base rod.

(c) connecting the lower end of the extension rod 230 to the upper end of the base rod 210 so as to extend the length of the base rod 210 (P3);

-It is possible to connect the base rod and the extension rod directly, but it is preferable to connect them by a connecting member.

(d) forming an insulating foam on the upper surface of the thermal insulation layer 300 by a foam-free spraying method to form an additional plurality of upper thermal insulation layers 400 (P4);

-The upper insulation foam is formed on the upper surface of the insulation layer remaining in the existing tank by a foam-free spray method.

(e) disposing a metal plate 600 having a through hole to penetrate the extension rod 230 as a finishing material at a predetermined distance from the upper surface of the upper insulating layer 400 (P5);

(f) forming an uppermost insulating foam layer with polyurethane by injecting in a foam-free spray manner to the side of the space 630 between the upper insulating layer and the metal plate (P6);

(g) separating the extension rod 230 from the base rod 210 (P7);

(h) the step of additionally injecting and filling the insulating foam by a foam-free spray in the space where the extension rod 230 has been removed (P8); provides a method for insulating a liquefied gas tank.

In particular, the specific construction method of steps S5 to S8 of the first and second embodiments is considered in performing each step of steps P5 to P8.

100: tank
200: support rod
210: basic rod
220: connecting member
230: extension rod
240: coupling member
300: lower insulating layer, 310: mesh
400: upper insulating layer, 410: mesh
500: top insulation foam layer, 510: mesh
600: metal plate
610: through hole, 620: insulation block, 630: separation space
700: fiberglass mesh
800: woodblock

Claims (5)

Step (S1) of evenly coupling the base rod 210 evenly on the outer surface of the tank 100;
Forming a plurality of lower insulating layers 300 on the outer surface of the tank such that the upper end of the foundation rod 210 is not covered (S2);
Connecting the lower end of the extension rod 230 to the upper end of the base rod 210 so as to extend the length of the base rod 210 (S3);
Forming an insulating foam on the upper surface of the lower insulating layer 300 by a foam-free spraying method to form an additional plurality of upper insulating layers 400 (S4);
A step (S5) of disposing a metal plate 600 having a through hole through the extension rod 230 at a predetermined distance from the upper surface of the upper insulating layer 400;
Forming an uppermost insulating foam layer with polyurethane by injecting a foam-free spray to the side of the space 630 between the upper insulating layer and the metal plate (S6);
Separating the extension rod 230 from the base rod 210 (S7);
Step (S8) of additionally injecting the insulating foam by foam-free spray in the space where the extension rod 230 is removed (S8);
Insulating construction method of a liquefied gas tank comprising a.
In the method of insulating the liquefied gas tank to repair the finishing material provided on the upper surface of the insulating layer formed on the outer surface of the tank 100,
Removing the finishing material covered on the upper portion of the heat insulating layer (P1);
Forming a through hole to the outer surface of the tank at predetermined intervals in the heat insulating layer, inserting a base rod 210 into the through hole, and then additionally injecting and filling the insulating foam by a foam-free spray method (P2)
Connecting the lower end of the extension rod 230 to the upper end of the base rod 210 so as to extend the length of the base rod 210 (P3);
Forming a plurality of upper insulating layers 400 by forming an insulating foam on the upper surface of the insulating layer 300 by a foam-free spray method (P4);
A step (P5) of disposing a metal plate 600 having a through hole to pass through the extension rod 230 at a predetermined distance from the upper surface of the upper insulating layer 400 as a finishing material (P5);
Forming an uppermost insulating foam layer with polyurethane by injecting a foam-free spray method to the side of the space 630 between the upper insulating layer and the metal plate (P6);
Separating the extension rod 230 from the base rod 210 (P7);
A method of adiabatic construction of a liquefied gas tank comprising a step (P8) of additionally injecting and filling an insulating foam by a foam-free spray in the space where the extension rod 230 is removed.
The method according to claim 1 or 2,
In step S3 or step P3, the base rod 210 and the extension rod 230 are connected by a connecting member 220, wherein the connecting member 220 has a wide washer part 221 and an upper part vertically. By being made of a coupling portion 222, the lower portion of the washer portion 221 is combined with the upper end of the base rod 210, and the upper portion of the coupling portion 222 is separable from the lower portion of the extension rod 230. Insulation method of the liquefied gas tank, characterized in that the combination.
The method according to claim 1 or 2,
In step S5 or step P5, an insulating construction method of a liquefied gas tank, characterized in that a spacer 630 is formed by placing an insulating block 620 between the upper insulating layer 400 and the metal plate 600.
The method according to claim 1 or 2,
In step S5 or step P5, a method of insulating a liquefied gas tank characterized in that a metal plate 800 is added to the upper surface of the metal plate 600 to prevent the metal plate from swelling.

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