KR20170131039A - Liquefied gas storage tank - Google Patents

Abstract

A liquefied gas storage tank is disclosed. According to an embodiment of the present invention, the liquefied gas storage tank comprises: a barrier surrounding liquefied gas; an insulating panel surrounding the barrier; an anchor strip fixated to the insulating panel; and a fixing member coupled to an upper surface of the insulating panel by penetrating through the anchor strip, and fixing the anchor strip to the insulating panel. The anchor strip has an insertion hole into which the fixing member is inserted and one or more buffer holes formed to surround the insertion hole. According to an embodiment of the present invention, a load applied to the fixing member such as a rivet fixing the barrier to the insulating panel can be reduced by difference of thermal expansion coefficient of the barrier and the insulating panel, and damage to the insulating panel can be prevented.

Description

[0001] LIQUEFIED GAS STORAGE TANK [0002]

The present invention relates to a liquefied gas storage tank, and more particularly to a liquefied gas storage tank in which a barrier and an insulating panel are secured by an anchor strip.

Liquefied natural gas (LNG) is a liquid state material in which natural gas containing methane as a main component is cooled to -163 ° C or lower and its volume is reduced to 1/600. LNG storage tanks that store LNG are made of structures and materials that can withstand cryogenic temperatures due to gas liquefaction. The LNG storage tank is formed in a double-sealed structure including, for example, a primary barrier, an upper insulation panel, a secondary barrier, and a lower insulation panel. The primary barrier contacts the LNG to seal the LNG first. The secondary barrier functions to seal the leaked LNG to prevent the LNG from touching the inner hull when the LNG leaks from the primary barrier. The upper insulating panel may comprise a polyurethane insulating foam and a plywood member bonded to the upper surface of the insulating foam. For the installation of the primary barrier, the anchor strip is riveted to the upper surface of the flywood member. The primary barrier is welded to the anchor strip.

When LNG is shipped to a cargo hold, the temperature of the cargo hold is lowered, causing the primary barrier adjacent to the LNG and the plywood member to shrink. The extent to which the primary barrier and plywood member shrinks depends on the thermal expansion coefficient. The thermal expansion coefficient of the flywood member is 5.5 × 10 ^-6 m / mK. When the primary barrier and the anchor strip are made of SS304L, the thermal expansion coefficient is about 16.9 × 10 ^-6 m / mK, which is about three times that of the plywood member. The larger the thermal expansion coefficient, the greater the length change with the same temperature change. Therefore, the primary barrier and anchor strip tend to shrink more than the ply wood member, while the plywood does not shrink as much as the thermal barrier. In this process, a large load of several thousand N may be applied to the rivets securing the primary barrier to the flywood member, which may result in breakage of the plywood and the heat-insulating foam, which are relatively weak in strength.

The present invention can reduce a load acting on a fixing member (for example, a rivet) for fixing a barrier to a heat insulating panel due to a difference in thermal expansion coefficient between the barrier and the heat insulating panel, Provide a tank.

The problems to be solved by the present invention are not limited to the above-mentioned problems. Other technical subjects not mentioned will be apparent to those skilled in the art from the description below.

A liquefied gas storage tank according to one aspect of the present invention includes a barrier surrounding a liquefied gas; An insulating panel surrounding the barrier; An anchor strip fixed on the heat insulating panel; And a fixing member coupled to the upper surface of the heat insulating panel through the anchor strip and fixing the anchor strip on the heat insulating panel, wherein the anchor strip includes: an insertion hole into which the fixing member is inserted, And a strip body having one or a plurality of buffer holes formed to surround the balls.

The plurality of buffer holes may be formed at regular intervals along the circumferential direction around the insertion hole.

The strip body may have buffer legs formed between the plurality of buffer holes and buffering the fixing member in a planar direction of the strip body.

The anchor strip may further include a buffer member inserted into the buffer hole.

When the barrier is contracted, the insertion hole is eccentric in the direction opposite to the contraction direction of the barrier with respect to the plurality of buffer holes, thereby reducing a load acting on the insulating panel by the fixing member.

According to the embodiment of the present invention, it is possible to reduce a load applied to a fixing member (for example, a rivet) for fixing the barrier to the heat insulating panel due to a difference in thermal expansion coefficient between the barrier and the heat insulating panel, A liquefied gas storage tank is provided.

The effects of the present invention are not limited to the effects described above. Unless stated, the effects will be apparent to those skilled in the art from the description and the accompanying drawings.

1 is a partially cutaway perspective view showing a liquefied natural gas storage tank 10 according to an embodiment of the present invention.
2 is an enlarged cross-sectional view of the portion 'A' of FIG.
FIG. 3 is an enlarged cross-sectional view of the 'B' portion of FIG. 2. FIG.
4 is a plan view of an anchor strip constituting a liquefied gas storage tank according to an embodiment of the present invention.
FIG. 5 is a view for explaining an operational effect of the liquefied gas storage tank according to the embodiment of the present invention.
6 to 9 are plan views of an anchor strip constituting a liquefied gas storage tank according to various embodiments of the present invention.

Other advantages and features of the present invention and methods of achieving them will be apparent by referring to the embodiments described hereinafter in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and the present invention is only defined by the scope of the claims. Although not defined, all terms (including technical or scientific terms) used herein have the same meaning as commonly accepted by the generic art in the prior art to which this invention belongs. A general description of known configurations may be omitted so as not to obscure the gist of the present invention. In the drawings of the present invention, the same reference numerals are used as many as possible for the same or corresponding configurations. To facilitate understanding of the present invention, some configurations in the figures may be shown somewhat exaggerated or reduced.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises", "having", or "having" are intended to specify the presence of stated features, integers, steps, operations, components, Steps, operations, elements, parts, or combinations thereof, whether or not explicitly described or implied by the accompanying claims.

The liquefied gas storage tank according to the embodiment of the present invention can be used to store liquefied gas such as liquefied natural gas (LNG), liquefied petroleum gas (LPG), and the like. The liquefied gas storage tank according to an embodiment of the present invention includes an insulating panel and an anchor (not shown) through which a fixing member (e.g., a rivet) is inserted to prevent an excessive load from being applied to the heat insulating panel due to a difference in thermal expansion coefficient between the insulating panel and a barrier welded thereto. One or a plurality of buffer holes are formed around the insertion hole of the strip. According to the embodiment of the present invention, when the barrier wall is contracted, the insertion hole is eccentric in the direction opposite to the contraction direction of the barrier with respect to the plurality of buffer holes, the load applied to the heat insulating panel by the fixing member is reduced, . Hereinafter, a liquefied gas storage tank according to an embodiment of the present invention will be described by taking a liquefied natural gas storage tank as an example. It should be noted, however, that the liquefied gas storage tank of the present invention may be applied to store liquefied gas such as liquefied petroleum gas in addition to liquefied natural gas.

1 is a partially cutaway perspective view showing a liquefied natural gas storage tank 10 according to an embodiment of the present invention. 2 is an enlarged cross-sectional view of the portion 'A' of FIG. The LNG storage tank 10 is provided with a primary barrier 11, a primary insulation panel 12, a secondary barrier 15 and a secondary insulation panel 16 from the space where the LNG is stored toward the inner hull 20 And has a double-layered structure in which layers are sequentially stacked.

The secondary insulation panel 16 may be provided as an insulating board positioned between the secondary barrier 15 and the inner hull 20. In one embodiment, the secondary insulation panel 16 includes a lower protection plate 162 fixed to the inner hull 20 by a fixing member (not shown), and a lower insulation member 161 attached to the lower protection plate 162 Lt; / RTI > The secondary insulation panel 16 may be installed in the inner hull 20 via a mastic 17. [

The primary insulation panel 12 is formed so as to surround the primary barrier 11. The primary insulating panel 12 may be provided as a heat insulating board positioned between the primary barrier 11 and the secondary barrier 15. [ The primary heat insulating panel 12 is composed of an upper heat insulating member 121 provided on the secondary barrier 15 by bolts or the like and an upper protective plate 122 attached to the upper heat insulating member 121 .

The upper heat insulating member 121 and the lower heat insulating member 161 are formed of a material having excellent heat insulating property such as polyurethane foam to provide heat insulation between the inner hull 20 and the LNG. The upper shielding plate 122 and the lower shielding plate 162 may be formed of plywood to give mechanical stiffness to the primary insulating panel 12 and the secondary insulating panel 16, respectively.

The secondary insulation panels 16 are made of a pre-designed area and placed on the inner hull 20 at a distance from each other. The spacing of the secondary insulating panels 16 can be set within a range that absorbs the shrinkage and expansion of the heat insulating board. The primary insulation panels 12 are disposed on the secondary barrier 15 at a distance from each other. The spacing of the primary insulating panels 12 may be set within a range that absorbs shrinkage and expansion of the heat insulating board. The gap between the primary insulating panels 12 and / or between the secondary insulating panels 16 can be filled with a heat insulating material having elasticity such as glass wool.

In one embodiment, the secondary barrier 15 may include a primary secondary barrier 151 and an auxiliary secondary barrier 152. The primary secondary barrier 151 and the secondary secondary barrier 152 are provided in a triplex formed of a metal composite laminate having a metal foil on both sides of a glass-fiber composite . The primary secondary barrier 151 is disposed on the upper surface of the secondary insulation panel 16. The primary secondary walls 151 disposed on the adjacent secondary insulating panels 16 are arranged side by side at regular intervals. The auxiliary secondary barrier 152 is formed to seal the gap of the primary secondary walls 151. The main secondary barrier 151 is fixed to the secondary insulation panel 16 by bolts or the like or is welded to the anchor strip provided on the upper surface of the secondary insulation panel 16 or by other methods Can be fixed on the secondary insulation panel 16. The secondary secondary barrier 152 may be attached on the primary secondary barrier 151 by an adhesive or the like.

The primary barrier 11 is formed to surround the LNG to seal the LNG. The primary barrier 11 may be provided as a membrane formed of a metal resistant to low-temperature brittleness such as aluminum alloy, Invar, nickel steel, and stainless steel sheet. The primary barrier 11 may have a corrugation 11a to accommodate the expansion and contraction of the LNG storage tank as the temperature changes. The primary barrier 11 can be installed on the primary insulation panel 12 by a method of welding with the anchor strip 13 provided on the upper surface of the primary insulation panel 12. [ The anchor strip 13 can be fixed to the upper surface of the primary heat-insulating panel 12 by a fixing member 14 such as a rivet.

FIG. 3 is an enlarged cross-sectional view of the 'B' portion of FIG. 2. FIG. 4 is a plan view of an anchor strip constituting a liquefied gas storage tank according to an embodiment of the present invention. 1 to 4, the fixing member 14 is coupled to the upper protection plate 122 through the anchor strip 13 through the insertion hole 132 formed in the strip body 131, thereby fixing the anchor strip 13 ) Is fixed on the primary heat insulating panel (12). The fixing member 14 may be provided by a fixing means such as, for example, a rivet or a bolt.

The primary barrier 11 and the anchor strip 13 have a property of shrinking more than the upper protection plate 122 when the LNG is shipped because the thermal expansion coefficient is about three times larger than the upper protection plate 122. The upper protection plate 122 is provided with a shrinkage load acting on the upper end of the fixing member 14 inserted into the anchor strip 13 and a shrinkage load acting on the lower end of the fixing member 14 inserted into the upper protection plate 122 The load is applied by the difference value.

In order to prevent a damage to the upper protective plate 122 due to a load applied to the upper protective plate 122 due to a difference in thermal expansion coefficient between the primary barrier 11 and the upper protective plate 122, A plurality of buffer holes 133 are formed so as to surround the insertion holes. A plurality of buffer holes 133 are formed in the circumferential direction about the insertion holes 132 so that the fixing member 14 can be deformed in an arbitrary direction on the plane of the anchor strip 13 And may be formed at regular intervals. Between the plurality of buffer holes 133, cushioning legs 134 for buffering the fixing member 14 in the plane direction of the strip body 131 are formed.

In the embodiment shown in Fig. 4, four buffer holes 133 having an arc shape are formed, but the shape, size, and number of the buffer holes 133 are not limited to the types of liquefied gas, And can be variously modified accordingly. Also, the width, length, and shape of the cushion bridge 134 can be variously changed according to the applied environment and the material of the cargo hold.

FIG. 5 is a view for explaining an operational effect of the liquefied gas storage tank according to the embodiment of the present invention. 3 and 5, when an excessive load is generated in the primary wall 11 in the shrinking direction, the anchor strip 13 can easily deform the insertion hole 132 and the fixing member 14 inserted therein . Therefore, when the primary barrier 11 is contracted, the insertion hole 132 is eccentric in the direction opposite to the contraction direction of the primary barrier 11 with respect to the plurality of buffer holes 133. As a result, the load acting on the primary heat insulating panel 12 is reduced by the fixing member 14.

6 to 9 are plan views of an anchor strip constituting a liquefied gas storage tank according to various embodiments of the present invention. In the description of the embodiments of FIGS. 6 to 9, the same or similar elements as those of the above-described embodiments may be omitted from the overlapping description. 6 to 8, the number and shape of the buffer hole 133 and the buffer leg 134 can be variously modified.

Referring to FIG. 8, a buffer member 135 may be inserted into the buffer hole 133. The buffer member 135 may be provided as a material having elasticity such as melamine foam. The buffer member 135 can prevent the buffer leg 134 from being damaged due to an excessive load. The buffer member 135 may be fitted in the buffer hole 133 or may be fixed with an adhesive. In the embodiment of FIG. 9, the buffer hole 133 is formed by a ring-shaped hole surrounding the insertion hole 132, and the position of the insertion hole 132 is determined by the ring- It can be deformed.

However, when the secondary barrier is welded and fixed to the anchor strip provided on the upper surface of the secondary insulation panel, the liquefied gas storage tank according to the present embodiment is provided with the secondary It is also possible to prevent damages to the secondary insulation panel by forming a buffer hole in the anchor strip provided on the insulation panel. In the case of the secondary barrier, since the amount of heat shrinkage is relatively smaller than that of the primary barrier, the number, size, and width (diameter) of the buffer holes and the buffering legs of the anchor strip formed on the upper surface of the secondary insulation panel, The anchor strip can be designed differently from the anchor strip formed on the upper surface of the anchor strip.

It is to be understood that the above-described embodiments are provided to facilitate understanding of the present invention, and do not limit the scope of the present invention, and it is to be understood that various modifications are possible within the scope of the present invention. It is to be understood that the technical scope of the present invention should be determined by the technical idea of the claims and the technical scope of protection of the present invention is not limited to the literary description of the claims, To the invention of the invention.

10: liquefied gas storage tank 11: primary barrier
11a: corrugation part 12: primary insulation panel
121: upper heat insulating member 122: upper shield plate
13: anchor strip 131: strip body
132: insertion hole 133: buffer hole
134: buffer bridge 135: buffer member
14: fixing member 15: secondary barrier
151: primary secondary barrier 152: secondary secondary barrier
16: secondary insulation panel 162: bottom protection plate
161: lower heat insulating member 20: inner hull

Claims (5)

A barrier surrounding the liquefied gas;
An insulating panel surrounding the barrier;
An anchor strip fixed on the heat insulating panel; And
And a fixing member coupled to the upper surface of the heat insulating panel through the anchor strip to fix the anchor strip on the heat insulating panel,
The anchor strip comprises:
An insertion hole into which the fixing member is inserted; and a strip body having one or more buffer holes formed to surround the insertion hole. The method according to claim 1,
Wherein the plurality of buffer holes are formed at regular intervals along the circumferential direction about the insertion hole. The method according to claim 1,
The strip body comprises:
And buffer legs formed between the plurality of buffer holes to buffer the fixing member in a planar direction of the strip body. The method according to claim 1,
Wherein the anchor strip further comprises a buffer member inserted into the buffer hole. The method according to claim 1,
Wherein the inserting hole is eccentric in a direction opposite to a contraction direction of the barrier with respect to the plurality of buffer holes to reduce a load acting on the heat insulating panel by the fixing member upon contraction of the barrier.

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