WO2024112022A1

WO2024112022A1 - Dual tank having displacement-absorbing structure

Info

Publication number: WO2024112022A1
Application number: PCT/KR2023/018624
Authority: WO
Inventors: 하재진; 이창환; 박현준
Original assignee: 주식회사래티스테크놀로지
Priority date: 2022-11-25
Filing date: 2023-11-20
Publication date: 2024-05-30
Also published as: KR102638970B1

Abstract

The present invention relates to a dual tank having a displacement-absorbing structure. The purpose of the present invention is to provide a dual tank having a displacement-absorbing structure, the dual tank using an elastic structure to absorb the contraction displacement caused by a sudden and extreme difference in temperature between the interior and the exterior of the dual tank during the flow of a cryogenic fluid into same.

Description

Double tank with displacement absorption structure

The present invention relates to a double tank having a displacement absorption structure, and more specifically, to a double tank having a manhole structure that can absorb shrinkage displacement caused by the temperature difference between the inside and outside when low-temperature fluid flows into the tank.

A pressure tank is a container that accommodates fluid under pressure and is manufactured to withstand pressure for the purpose of storing, reacting, and separating liquid or gas. It is generally used to transport or store oxygen, nitrogen, argon, and natural gas with a critical temperature of -50°C or lower in liquid form. In particular, since liquefied gas is at a cryogenic temperature of -150℃ or lower, cryogenic containers must be insulated to prevent an increase in liquid temperature due to heat immersion from the outside, that is, an increase in container pressure, and the material of the container must be a material that does not cause low-temperature embrittlement. must be used.

Unlike regular containers, cryogenic containers have a double-walled structure with an inner tank and an outer tank. The inner tank is a low-temperature tank in which low-temperature fluid is stored, and the outer tank installed along the outer circumference of the low-temperature tank is a protection tank that protects the low-temperature tank. Opening and closing parts are installed on the outer circumference of the protection tank and the low-temperature tank to allow fluid injection. .

The conventional double pressure tank structure will be described with reference to FIG. 1. As shown in FIG. 1, the conventional double tank is formed in a dual structure in which the inner tank 10 is accommodated in the outer tank 20 at a preset interval, and each of the inner tank 10 and the outer tank 20 has An inner tank through hole 15 and an outer tank through hole 25 are formed, and a passage portion 30 is formed around the inner tank through hole 15 to communicate with the inner space of the inner tank 10 and the external environment. At this time, the outer surface of the passage portion 30 and the outer shell hole 25 are connected so that the space between the inner shell 10 and the outer shell 20 can be sealed. The space between the inner tank 10 and the outer tank 20 forms an insulating layer by maintaining a vacuum.

Normally, as shown in the overall drawing of FIG. 1, the inner through hole 15 and the outer through hole 25 are closed by separate lids, but in case of fluid inflow, as shown in the dotted oval in FIG. The lids are opened. At this time, since one end of the passage portion 30 is coupled to the outer surface of the inner tank 10 and the side of the passage portion 30 is coupled to seal the outer tank through hole 25 while penetrating the outer tank through hole 25, the inner tank 10 ) and the outer tank 20 are still kept in a sealed state.

Meanwhile, when fluid flows into the inner space of the inner tank 10, the fluid flows in at a very low temperature of -150°C, so the internal temperature of the inner tank 10 rapidly decreases, causing shrinkage of the inner tank 10. When the inner tank 10 is contracted, the passage portion 30 is pulled toward the center of the inner tub 10. As described above, since the side of the passage portion 30 is coupled to the outer tub hole 25, the inner tub ( 10) When shrinking, stress is concentrated at the joint between the passage portion 30 and the outer hole 25. This naturally causes cracks to occur, which causes a major problem in that the vacuum and insulation of the space between the inner tank 10 and the outer tank 20 cannot be maintained stably.

[Prior art literature]

[Patent Document]

(Patent Document 1) Republic of Korea Patent Publication No. 10-2014-0131372 (“LNG tank”, November 12, 2014)

Therefore, the present invention was created to solve the problems of the prior art as described above, and the purpose of the present invention is to use an elastic structure to prevent shrinkage displacement caused by a sharp temperature difference between the inside and outside during the process of introducing ultra-low temperature fluid into a double tank. To provide a double tank having a displacement absorption structure to absorb.

A double tank 100 having a displacement absorbing structure of the present invention to achieve the above-described object includes an inner tank 110 in which an internal space is formed; An outer tank (120) in which the inner tank (110) is accommodated in an internal space at a preset interval; A passage portion 130 extending from the inner tank 110 through the outer tank 120 to the external environment to communicate with the internal space of the inner tank 110 and the external environment; An inner connection portion 121 formed to surround a lower side of the passage portion 130 and fixedly coupled to the outer tub 120; An outer connection portion 122 formed to surround an upper side of the passage portion 130 and fixedly coupled to the passage portion 130; An elastic part 140 made of an elastic material and provided between the inner connection part 121 and the outer connection part 122; an insulating layer 150 formed by vacuuming the space between the inner tank 110 and the outer tank 120; may include.

At this time, in the double tank 100, the displacement generated along the extending direction of the passage portion 130 in the passage portion 130 as the inner tank 110 shrinks or expands due to temperature changes is caused by the elastic portion. It may be configured to be applied to (140).

In addition, in the double tank 100, the passage portion 130 and the outer connection portion 122 are fixedly coupled to each other, and the passage portion 130 and the inner connection portion 121 are slidably coupled to each other, so that the inner tank 100 Displacement generated in the passage portion 130 according to contraction or expansion of 110 may occur as a change in the gap between the inner connection portion 121 and the outer connection portion 122.

In addition, the double tank 100 has an outer tank 125 formed on the outer tank 120 at a portion where the passage portion 130 penetrates the outer tank 120, and the inner circumferential surface of the outer tank 125 and the The side surfaces of the passage portion 130 may be formed in close contact.

Additionally, in the double tank 100, the inner connection portion 121 may surround the outer tank hole 125 and protrude from the outer surface of the outer tank 120 toward the external environment.

In addition, the elastic portion 140 has one end connected to the other end of the inner connection portion 121 and an inner extension portion 141 extending along the extension direction of the passage portion 130, and the other end of the outer connection portion 122. The outer extension part 142, which is connected to one end and extends along the extension direction of the passage part 130, is connected between the inner extension part 141 and the outer extension part 142, and is formed in a curved elastic shape. It may include a deformation portion 145.

In addition, the elastic portion 140 has a convex shape including a point where the elastic deformable portion 145 protrudes beyond the inner extension portion 141 and the outer extension portion 142 in the radial direction of the passage portion 130. It can be formed in a curved shape.

Additionally, the elastic portion 140 may be formed so that the inner circumferential surface of the elastic deformable portion 145 contacts and supports the side surface of the passage portion 130.

Additionally, the elastic portion 140 may include the inner extension portion 141, the outer extension portion 142, and the elastic deformation portion 145 integrally formed.

According to the present invention, the manhole with an elastic structure effectively absorbs the shrinkage displacement caused by the rapid temperature difference between the inside and the outside during the process of ultra-low temperature fluid flowing into the double tank, which ultimately has the great effect of preventing the occurrence of cracks in the tank and the connection part. There is. Of course, this crack generation suppression effect also has the effect of maintaining the vacuum between the walls of the double tank more stably.

In addition, according to the present invention, the manhole structure itself for absorbing shrinkage displacement is not very complicated and can be easily realized, so there is an economic effect of saving resources such as time, cost, and manpower required for production. In addition, it has the advantage of high compatibility as it can be easily applied by replacing and installing the manhole structure of the present invention in an existing double tank.

Figure 1 is a cross-sectional view of a conventional double tank.

Figure 2 is an external view and a cross-sectional view of the main part of the double tank of the present invention.

3 shows the main structure of the present invention and the prior art.

Figure 4 shows the temperature gradient of main parts of the present invention and the prior art.

Figure 5 shows displacement due to thermal deformation of main parts of the present invention and the prior art.

Figure 6 shows stress due to thermal deformation of main parts of the present invention and the prior art.

** Explanation of symbols **

100: Double tank

110: Internal care 120: External care

121: inner connection part 122: outer connection part

125: Oejo Tonggong

130: Passage part 140: Elastic part

141: inner extension 142: outer extension

145: elastic deformation part 150: insulation layer

Hereinafter, a double tank having a displacement absorption structure according to the present invention having the above-described configuration will be described in detail with reference to the attached drawings.

Figure 2 shows an external view (upper view of Figure 2) and a cross-sectional view (lower view of Figure 2) of the main part of the double tank of the present invention. Referring to Figure 2, the double tank 100 of the present invention basically includes an inner tank 110, an outer tank 120, a passage portion 130, an elastic portion 140, and an insulating layer 150. An inner connection part 121 and an outer connection part 122 are formed in the outer tub 120 to connect it to the elastic part 140. Each part will be described in more detail below.

The inner tank 110, the outer tank 120, and the insulation layer 150 are the same as the inner tank, outer tank, and insulation layer of a conventional double tank. That is, the inner tank 110 has an internal space and stores fluid such as fuel in the internal space. The outer tank 120 is formed to accommodate the inner tank 110 in an internal space at a predetermined distance. In this way, the wall surface is formed in a double structure by providing the inner tank 110 and the outer tank 120 in order to prevent external heat intrusion into the inner tank 110 as much as possible. That is, the space between the inner tank 110 and the outer tank 120 is evacuated, thereby forming the heat insulating layer 150.

The passage portion 130 extends from the inner tank 110 through the outer tank 120 to the external environment and serves to communicate the internal space of the inner tank 110 with the external environment. Although not shown in FIG. 2, as in FIG. 1, one end of the passage portion 130 is formed to surround the inner tank hole formed in the inner tank 110 and is fixedly coupled to the inner tank 110. In addition, as indicated by a dotted line in the lower drawing of FIG. 2, an outer shell through hole 125 is formed on the outer shell 120 at a portion where the passage portion 130 penetrates the outer shell 120, and the inner circumferential surface of the outer shell hole 125 And the side surfaces of the passage portion 130 are brought into close contact.

Conventionally, as shown in FIG. 1, the inner peripheral surface of the outer barrel hole 125 and the side surface of the passage portion 130 were fixedly coupled, thereby maintaining the sealing of the heat insulating layer 150. Meanwhile, as the inner tank 110 is filled with a very low temperature fluid, thermal deformation such as shrinkage of the inner tank 110 occurs. At this time, since one end of the passage portion 130 is fixedly coupled to the inner tub 110, the inner tub 110 contracts, causing displacement in the passage portion 130. However, as described above, in the related art, since the side of the passage portion 130 is fixedly coupled to the inner peripheral surface of the outer shell hole 125, the tensile force is concentrated between the inner shell coupling portion and the outer shell coupling portion of the passage portion 130, In particular, stress is sharply concentrated at the outer shell coupling portion of the passage portion 130. This naturally causes damage to the part, and when this part is damaged, the sealing of the insulation layer 150 cannot be maintained, causing various problems such as greatly increasing the storage instability of the fluid stored in the low-temperature tank 110.

In the present invention, in order to solve this problem, the connection structure between the inner shell 110 / the outer shell 120 / the passage portion 130 is improved and the elastic portion 140 is provided to form the elastic portion 140. Ensure that the displacement is applied concentrated. To explain in more detail, first, in the present invention, the inner connection portion 121 is formed to surround the lower side of the passage portion 130 and is fixedly coupled to the outer tub 120, and surrounds the upper side of the passage portion 130. It is formed and has an outer connection part 122 that is fixedly coupled to the passage part 130. At this time, the elastic part 140 is formed of an elastic material and is provided between the inner connection part 121 and the outer connection part 122.

When the inner tank 110 contracts or expands due to temperature changes, displacement occurs in the passage portion 130 along the direction in which the passage portion 130 extends, as described above. At this time, according to the connection structure of the present invention, the displacement generated in this way is concentrated and applied to the elastic part 140 due to the provision of the elastic part 140 capable of shape deformation. To be more specific, in the present invention, the passage portion 130 and the outer connection portion 122 are fixedly coupled to each other, and the passage portion 130 and the inner connection portion 121 are slidably coupled to each other.

Accordingly, the displacement generated in the passage portion 130 as the inner tank 110 contracts or expands occurs as a change in the gap between the inner connection portion 121 and the outer connection portion 122. However, since the elastic part 140, which can actually change shape, is provided between them, this displacement is directly applied to the elastic part 140. As the elastic part 140 absorbs all of the displacement, no displacement occurs in other parts, and thus excessive stress concentration in other parts can be suppressed.

Meanwhile, as described above, the passage portion 130 and the outer connection portion 122 are fixedly coupled to each other, and the passage portion 130 and the inner connection portion 121 are slidably coupled. More specifically, as shown, the inner connection portion 121 surrounds the outer tank hole 125 and protrudes from the outer surface of the outer tank 120 toward the external environment. This part can slide because a fine gap is formed. That there is. That is, the insulation layer 150 may not be properly sealed up to the vicinity of the inner connection portion 121. However, the outer connection part 122 is fixedly coupled to the passage part 130, and the gap is completely closed here. Accordingly, the insulation layer 150 can achieve complete sealing by fixing the passage portion 130 and the outer connection portion 122.

Of course, the elastic part 140 may be formed only of an elastic material, but it is preferable that the elastic part 140 be formed in a special shape as shown in order to absorb displacement more effectively. Specifically, as shown in the lower view of FIG. 2, the elastic portion 140 is an inner extension portion that has one end connected to the other end of the inner connection portion 121 and extends along the extension direction of the passage portion 130. (141), the other end is connected to one end of the outer connection portion 122, the outer extension portion 142 extending along the extension direction of the passage portion 130, the inner extension portion 141, and the outer extension portion ( 142) and may include an elastic deformation portion 145 formed in a curved shape.

In particular, the elastic deformation portion 145 includes a point where the elastic deformation portion 145 protrudes beyond the inner extension portion 141 and the outer extension portion 142 in the radial direction of the passage portion 130. It can be formed in a convex curved shape. That is, the radial outer shape of the elastic deformation portion 145 can be formed close to the donut outer shape. By doing this, it becomes possible to absorb displacement more smoothly not only materially but also in terms of shape.

In addition, the elastic deformation portion 145 is preferably formed so that the inner peripheral surface of the elastic deformation portion 145 is in contact with the side surface of the passage portion 130, as shown in the cross-sectional view of the lower view of FIG. 2. Of course, the inner and outer ends of the elastic deformation portion 145 may be directly connected to the inner extension portion 141 and the outer extension portion 142, respectively. However, in this case, undesirable side effects in the buckling direction may occur. There is a risk of deformation occurring. However, as shown in the cross-sectional view in the lower view of FIG. 2, when the inner circumferential surface of the elastic deformable portion 145 is formed in a shape that is in contact with the side of the passage portion 130 and supported, the support portion acts as a kind of leg to maintain this buckling direction. Transformation can be effectively suppressed.

Additionally, of course, it is preferable that the inner extension part 141, the outer extension part 142, and the elastic deformation part 145 of the elastic part 140 are formed as one piece. The elastic part 140 may be made of a material such as rubber, which is widely used as an elastic material, and the elastic part 140 can be easily made into an integrated form using a mold or the like.

According to the present invention, even if thermal deformation such as contraction or expansion of the inner shell 110 occurs, the elastic portion 140 is provided between the inner shell connection portion and the outer shell connection portion of the passage portion 130. , the elastic portion 140 suppresses stress concentration by absorbing all displacement.

Figures 3 to 6 are the results of actually performing thermal deformation structural analysis to confirm the extent to which this effect actually occurs. Figure 3 shows the main structure of the present invention and the prior art, and Figure 4 shows the temperature gradient of the main parts of the present invention and the conventional art. In general, in the case of a double tank storing low-temperature fluid, the outer tank part can be set to about 300K because it is in a room temperature environment, and the inner tank part can be set to about 20K because it stores low-temperature fluid.

Figure 5 compares the displacements generated by thermal deformation of main parts of the present invention and the prior art. As explained previously, significant shrinkage occurs in the inner tank as it decreases to low temperature. At this time, in the case of the present invention (top view), since the passage part is connected to the outer tank by an elastic part, the passage part naturally moves toward the center of the inner tank as the inner tank shrinks (downward direction in the drawing). However, in the conventional case (lower drawing), since the passage portion is fixedly coupled to the outer tank and there is no shape deformation in the outer tank, the passage portion is firmly held by the outer tank due to the rigidity of the structure, and eventually displacement occurs in the passage portion. I never do that.

Figure 6 compares the stress generated by thermal deformation of main parts of the present invention and the prior art. As described above, in the present invention, when shrinkage of the inner tank occurs, displacement naturally occurs in the passage portion, and this displacement is absorbed by the elastic portion capable of shape deformation. Accordingly, as shown in the top view of FIG. 5, in the present invention, the stress is almost entirely formed close to 0, that is, it can be said that almost no stress concentration occurs in the structure. On the other hand, in the case of the related art, as described above, a state is formed in which the passage is tightly held and pulled on both sides, so a significant stress is generated from the passage. In particular, as can be seen in the lower view of FIG. 5, a stress exceeding 200 MPa occurs at the outer end of the connection area between the passage part and the outer shell connection part. Considering that the allowable stress of stainless steel 304, which is generally widely used as a material for such passage parts, is 205 MPa, it can be seen that in the conventional case, there is a very high risk of damage because the elastic part as in the present invention is not provided.

The present invention is not limited to the above-described embodiments, and its scope of application is diverse, and anyone skilled in the art can understand it without departing from the gist of the invention as claimed in the claims. Of course, various modifications are possible.

According to the present invention, the occurrence of cracks in the tank and the connection can be prevented through a simple structure during the process of ultra-low temperature fluid flowing into the double tank, thereby providing an economical product that can save resources such as time, cost, and manpower required for production. It works. In addition, it has the advantage of high compatibility as it can be easily applied by replacing and installing the manhole structure of the present invention in an existing double tank.

Claims

An inner bath (110) in which an internal space is formed;

An outer tank (120) in which the inner tank (110) is accommodated in an internal space at a preset interval;

A passage portion 130 extending from the inner tank 110 through the outer tank 120 to the external environment to communicate with the internal space of the inner tank 110 and the external environment;

An inner connection portion 121 formed to surround a lower side of the passage portion 130 and fixedly coupled to the outer tub 120;

An outer connection portion 122 formed to surround an upper side of the passage portion 130 and fixedly coupled to the passage portion 130;

An elastic part 140 made of an elastic material and provided between the inner connection part 121 and the outer connection part 122;

an insulating layer 150 formed by vacuuming the space between the inner tank 110 and the outer tank 120;

A double tank comprising:
The method of claim 1, wherein the double tank 100,

Characterized in that the displacement generated in the passage portion 130 along the extending direction of the passage portion 130 is applied to the elastic portion 140 as the inner tank 110 contracts or expands due to temperature changes. Double tank.
The method of claim 2, wherein the double tank 100,

The passage portion 130 and the outer connection portion 122 are fixedly coupled to each other, and the passage portion 130 and the inner connection portion 121 are slidably coupled,

A double tank, characterized in that the displacement generated in the passage part 130 according to the contraction or expansion of the inner tank 110 is generated as a change in the gap between the inner connection part 121 and the outer connection part 122.
The method of claim 3, wherein the double tank 100,

An outer shell hole 125 is formed on the outer shell 120 at a portion where the passage portion 130 penetrates the outer shell 120,

A double tank, characterized in that the inner circumferential surface of the outer barrel hole (125) and the side surface of the passage portion (130) are in close contact with each other.
The method of claim 4, wherein the double tank 100,

A double tank, characterized in that the inner connection portion 121 surrounds the outer tank hole 125 and protrudes from the outer surface of the outer tank 120 toward the external environment.
The method of claim 2, wherein the elastic portion 140 is:

An inner extension portion 141, one end of which is connected to the other end of the inner connection portion 121 and extending along the direction of extension of the passage portion 130,

An outer extension portion 142, the other end of which is connected to one end of the outer connection portion 122 and extending along the extension direction of the passage portion 130,

An elastic deformation part 145 is connected between the inner extension part 141 and the outer extension part 142 and is formed in a curved shape.

A double tank comprising:
The method of claim 6, wherein the elastic portion 140 is:

Characterized in that the elastic deformation portion 145 is formed in a convex curved shape including a point protruding from the inner extension portion 141 and the outer extension portion 142 in the radial direction of the passage portion 130. Double tank.
The method of claim 7, wherein the elastic portion 140 is:

A double tank, characterized in that the inner peripheral surface of the elastic deformation part (145) is formed to contact and support the side surface of the passage part (130).
The method of claim 6, wherein the elastic portion 140 is:

A double tank, characterized in that the inner extension part 141, the outer extension part 142, and the elastic deformation part 145 are formed as one piece.