KR101434146B1 - Connecting structure of insulating barrier - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-temperature or high-temperature liquid tank, for example, a heat insulating barrier joint structure of a cargo hold of a liquefied natural gas carrier. More particularly, the present invention relates to a thermal barrier bonding structure capable of minimizing the stress of a bonding portion. The heat insulating barrier bonding structure according to the present invention is characterized in that a face sheet joined to the surface of a plurality of heat insulating panels arranged at regular intervals and a face sheet bonded to the surface of two adjacent heat insulating panels so as to cover the gaps between the heat insulating panels And a strip bonded to the bonded face sheet. Wherein the face plate and the strip have different structural stiffnesses. The heat insulating barrier bonding structure according to the present invention uses a sheet having structural rigidity suitable for strips covering the gap between the face plate joined to the heat insulating panel and the heat insulating panel so as to prevent thermal deformation of the lamination portion of the strip and Thermal stress can be minimized.

Description

{CONNECTING STRUCTURE OF INSULATING BARRIER}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-temperature or high-temperature liquid tank, for example, a heat insulating barrier joint structure of a cargo hold of a liquefied natural gas carrier. More particularly, the present invention relates to a thermal barrier bonding structure capable of minimizing the stress of a bonding portion.

Cryogenic liquids such as Liquefied Natural Gas (LNG), Liquid Argon, Liquid Nitrogen, and Liquid Oxygen are used in storage tanks with an insulating structure to minimize evaporative losses. Stored or transported.

An example of a cryogenic liquid storage tank is a cargo containment system of an LNG carrier. LNG cargo holds are designed to store and transport cryogenic LNG at -165 ° C. It has a spherical type and a membrane type. Membrane type tanks with larger capacity and easier to manufacture than spherical type tanks Is preferred.

A gas transport system and a technigaz system developed by the company Gas Transport Et Technigaz (GTT, France) in France are used for the cooling system of the membrane type LNG carrier have. The Gaz Transport system is called GTT No96, and the Technigaz system is called the GTT Mark-III system.

Invar (36% nickel steel), which has a very low coefficient of thermal expansion, is used as the material of the first and second barriers of the Gaz transport system. A heat insulating box filled with pearlite is used between the first and second walls.

A stainless steel sheet having a corrugated shape is used as a first barrier of the Technigaz system to absorb shrinkage and expansion due to thermal deformation and a second barrier is made of aluminum foil Triplex, in which glass fiber composite is bonded on both sides, is used. And a polyurethane foam serving as a heat insulating material is mounted between the first and second barrier walls. On one side of the polyurethane foam, a protection plate made of a plywood or a composite material is bonded.

Although the gas evacuation rate (BOR) of the gas transport system and the technigaz system are known to be similar, the cost of stainless steel sheets and triplexes is relatively low compared to the in-bar membrane, the construction is simple and the insulation effect of the polyurethane foam The Technicon system is preferred. As a related art, refer to Korean Patent Laid-Open Publication No. 10-2012-0061402 (published on Jun. 13, 2012).

The second barrier wall of the Gaz Transport system or the Technique system consists of a face plate bonded to the surface of the thermal insulation and a strip bonded to the face plate to cover the gap between the thermal insulation. In the conventional Gaz transport system or Technique system, the material of the face plate and the strip is not used separately, thereby causing high thermal deformation and thermal stress in the second barrier.

It is an object of the present invention to provide a novel adiabatic barrier bonding structure capable of stably maintaining sealing performance by minimizing thermal deformation and thermal stress by using sheets having different stiffnesses from each other using face plates and strips.

According to an aspect of the present invention, there is provided an adiabatic barrier bonding structure comprising: a face sheet bonded to a surface of a plurality of adiabatic panels arranged at regular intervals; and two adjacent adiabatic members covering a gap between the adiabatic panels, And a strip joined with a face material bonded to the surface of the heat insulating panels. Wherein the face plate and the strip have different structural stiffnesses.

It is preferable that the structural rigidity of the face plate and the strip having a large structural rigidity is 100 times or more of the structural rigidity of the small structural rigidity.

Further, it is preferable that the structural rigidity of the strip is larger. This is because it is difficult to fabricate the strip integrally. Therefore, when a large thermal deformation occurs in the overlapping portion, the overlapping portion having a relatively low fracture displacement may be broken.

For example, the face plate may be made of an aluminum sheet, and the strip may be made of a stainless steel sheet.

Further, a metal sheet having the same composition is used, and the face plate is a metal sheet subjected to annealing, and the strip may be a hardened metal sheet. The strip may be cured by heat treatment, work hardening, precipitation hardening, solid solution hardening, dispersion hardening or a combination thereof.

Further, it is possible to use a sheet having a corrugation formed on the face material, and a sheet having no curved portion formed on the strip.

Further, for the difference in structural rigidity, a sheet having a thinner thickness than the strip may be used for the face plate.

The heat insulating barrier bonding structure according to the present invention uses a sheet having structural rigidity suitable for strips covering the gap between the face plate joined to the heat insulating panel and the heat insulating panel so as to prevent thermal deformation of the lamination portion of the strip and Thermal stress can be minimized.

Also, through this, the sealing performance and the structural reliability of the thermal barrier bonding structure can be improved.

1 is a cross-sectional view schematically showing a cryogenic liquid storage tank having a thermal barrier bonding structure according to the present invention.
2 is a cross-sectional view schematically showing the adiabatic barrier bonding structure shown in Fig.
3 is a cross-sectional view showing another embodiment of the thermal barrier bonding structure according to the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the width, length, thickness, etc. of components may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

1 is a cross-sectional view schematically showing a cryogenic liquid storage tank having a thermal barrier bonding structure according to the present invention.

1, the cryogenic liquid storage tank includes a tank inner wall 110 having a storage space for storing cryogenic liquid therein, a tank inner wall 110 for preventing heat transfer between the tank inner wall 110 and the storage space, And a heat insulating structure 120 joined to the heat insulating structure 120. The heat insulating structure 120 is composed of heat insulating panels 121, 122 and 123, a primary barrier 124 and a secondary barrier 125 arranged in a multilayered manner.

The heat insulating panels 121, 122 and 123 are divided into an outer heat insulating panel 121 coupled to the tank inner wall 110 and an inner heat insulating panel 122 and a bridge thermal insulating panel 123 covering the outer heat insulating panel 121. [ . The bridge-insulating panel 123 is disposed between the inner insulating panels 122 to cover the gap between the two outer insulating panels 121.

The heat insulating panels 121, 122 and 123 are formed by sandwiching a heat insulating material 126, 127, or 128 such as polyurethane foam or the like and having reinforcing members 129, 130, . The outer heat insulating panel 121 is fixed to the tank inner wall 110 by an adhesive 115 or a stud bolt (not shown), and the inner heat insulating panel 122 and the bridge heat insulating panel 123 are bonded to each other And is fixed to the outer heat insulating panel 121 by a method.

The primary barrier 124 is for sealing the storage space so that the cryogenic liquid stored in the storage space is not leaked. An anchor strip (not shown) installed on the inner heat insulating panel 122 or the bridge heat insulating panel 123, And a plurality of barrier sheets 132 made of a metal and welded and fixed. The barrier sheet 132 constituting the primary barrier 124 may be made of various metal materials such as stainless steel or aluminum that does not cause deterioration of physical properties due to brittleness at a cryogenic temperature.

The primary barrier 124 has a plurality of corrugations 133 for suppressing the generation of thermal stress due to heat shrinkage. The corrugated portion 133 is formed to be convex in the storage space direction. The corrugated portion 133 prevents the welded portion from being damaged by the stress caused by the hot water generated when the primary barrier 124 contacts the cryogenic liquefied natural gas.

The secondary barrier 125 covers the outer heat insulating panel 121 to seal the cryogenic liquid secondarily when the primary barrier 124 is broken. The secondary barrier 125 is composed of a plurality of face members 135 covering the upper surface of the outer heat insulating panel 121 and a plurality of strips 134 covering the gap between the outer heat insulating panels 121. The strip 134 is made of a metal or a mixed material of a metal and a composite material and is bonded to the face plate 135 of the outer heat insulating panel 121 by an adhesive layer 138 such as a polymer adhesive or a film adhesive.

2 is a cross-sectional view schematically showing a thermal barrier bonding structure according to the present invention. 2, the thermal barrier bonding structure according to the present invention includes a face plate 135 bonded to the surfaces of a plurality of outer heat insulating panels 121 arranged at regular intervals, and a face plate 135 bonded to the outer heat insulating panels 121 As shown in FIG. The face plates 135 and the strips 134 are joined by means of gluing, welding or mechanical fastening. Since it is difficult to manufacture the strip 134 as an integrated type in construction, it is common to use a plurality of strips in a stacked manner. The bonding layer 138 and the strip overlapping portion of the face member 135 and the strip 134 are relatively weak to the thermal stress generated by the heat shrinkage of the outer heat insulating panel 121 by the cryogenic liquid.

The strips 134, face plates 135 and outer heat insulating panels 121 have a constant structural stiffness and heat shrinkage due to their shapes and materials and each element has an effect on surrounding elements by its structural stiffness and heat shrinkage amount. And is deformed until force equilibrium is achieved. The thermal stress caused by this equilibrium of force acts on each element. And the zero stress generated in the bonding layer 138 of the face material 135 and the strip 134 and in the strip overlap portion is an important factor for determining the secondary barrier reliability.

When the cryogenic liquid, for example liquefied natural gas, is stored inside the cryogenic liquid storage tank, tensile stress is applied to the strip 134 due to heat shrinkage of the outer heat-insulating panel 121. At this time, if both the face plate 135 and the strip 134 have low structural rigidity, a large thermal deformation occurs in the strip 134, and the strip 134 may be damaged. Further, breakage of the strip overlapping portion may occur.

Conversely, if the face members 135 and the strips 134 both have a high structural rigidity, thermal deformation of the strips 134 is reduced, but a large thermal stress is applied to the bonding layer 138 connecting the face plates 135 and the strips 134 Breakage of the bonding layer 138 of the face material 135 and the strip 134 having a relatively weak yield strength may occur.

A finite element method (FEM) and a spring model are used to calculate the structural rigidity of the face plate 135 and the strip 134 required for the design of the thermal barrier bonding structure. And the thermal stress and deformation amount according to the structural stiffness of the face member 135 were calculated.

The finite element analysis is used to calculate the structural stiffness and the heat shrinkage of the outer heat insulating panel 121 to which the face member 135 is attached. As the stiffness and the yield stress of the face member 135 increase, It was confirmed that the structural rigidity and the heat shrinkage amount of the outer heat insulating panel 121 were increased. Since the face member 135 attached to the outer heat insulating panel 121 is relatively rigid as compared with the outer heat insulating panel 121, the outer heat insulating panel 121 is formed of the same material as that of the outer heat insulating panel 121 The structural stiffness and the amount of heat shrinkage do not greatly affect the structural rigidity and the amount of heat shrinkage and the structural rigidity and the heat shrinkage amount of the outer heat insulating panel 121 to which the face member 135 is attached depend greatly on the physical properties of the face member 135.

As a result of the finite element analysis, the structural stiffness and heat shrinkage of the outer heat insulating panel 121 having the calculated face member 135 were utilized in calculating the equilibrium of force equations through the spring model.

Table 1 below shows the calculation results of the thermal stress and deformation amount depending on the types of the strips 134 and the face plates 135. As can be seen from Table 1, a sheet of 0.2 t of stainless steel (SUS304-O) having a high structural rigidity was used as the material of the strip 134, and aluminum (Al1050- O) 0.3t of sheet is used, the thermal stress and deformation amount are minimized.

The strip 134 having a high structural rigidity is minimized in thermal deformation and the laminate 135 having a low structural rigidity bonded thereto is subjected to a suitable thermal deformation so that the strip 134 and the joining layer 138 of the face plate 135 Thermal stress is minimized. In addition, the thermal stress of the overlapping portion of the strip 134 is also minimized. At this time, it is preferable that the structural rigidity of the strip 134 is 100 times or more of the structural rigidity of the face material 135.

Structural stiffness can be controlled by changing the shape and material.

For example, a steel material having high rigidity and yield strength can be used as the strip 134, and aluminum having a relatively low stiffness and yield strength can be used as the face material 135. [

Also, the same metal material is used, but the yield strength can be controlled by different heat treatment conditions. For example, the strip 134 can increase the yield strength through work hardening and the face plate 135 can lower the yield strength through loosening.

3, a convex wrinkle portion 136 may be formed on the face plate 135 in the direction of the outer heat insulating panel 121, or the face plate 135 may be thinned so that the face plate 135 has a low structural stiffness . At this time, it is also possible to form the corrugations 137 in the strip 134 so that the structural rigidity is larger than that of the face plate 135.

It is also possible to use a sheet having a low structural stiffness as the strip 134 and a sheet having a high structural rigidity as the face plate 135, contrary to the above. However, in the case of a non-integral strip, it is preferable that the structural rigidity of the strip 134 is made larger than the structural rigidity of the flange 135 in order to minimize the thermal deformation of the strip overlap portion.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: liquid storage tank 110: tank inner wall
120: heat insulating structure 121: outer heat insulating panel
122: Inner insulation panel 123: Bridge insulation panel
124: primary barrier 125: secondary barrier
132: barrier sheet 133:
134: strip 135: face plate
138: bonding layer

Claims (8)

A face plate joined to a surface of a plurality of heat insulating panels arranged at regular intervals,
And a strip which is joined to a face plate bonded to a surface of two adjacent heat insulating panels so as to cover a gap between the plurality of the heat insulating panels,
Wherein the strip has a greater structural rigidity than the face material. The method according to claim 1,
Wherein the strip has a structural rigidity greater than 100 times greater than the face material. The method according to claim 1,
Wherein the face plate is made of an aluminum sheet, and the strip is made of a stainless steel sheet. delete delete The method of claim 1, wherein
Wherein the face material is a sheet having a corrugation formed therein. The method according to claim 1,
Wherein the face material is a sheet thinner than the strip. The method according to claim 1,
Wherein the thermal barrier bonding structure is a secondary barrier of a cryogenic liquid storage tank.

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