JP3255057B2 - Strengthening method of existing tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing the strength of an existing tank, and more particularly, to a method for discharging an existing tank that satisfies the earthquake resistance of the existing tank and that is required when the stored liquid is a flammable substance or a dangerous substance. The present invention relates to a method for reinforcing the strength of an existing tank, which can obtain an optimum strength as an explosion structure.

[0002]

2. Description of the Related Art Conventionally, small tanks having a capacity of less than 1000 KL have been known. FIG. 4 shows the structure of such a small tank. In this figure, a small tank is installed (layed) on a foundation 1 or fixed on the foundation 1 by an anchor or the like, a tank side plate 3 welded and fixed to the bottom plate 2,
A top angle 4 as a top plate member welded and fixed to the upper portion of the tank side plate 3 and a roof plate 5 welded and fixed to an upper portion of the top angle 4 are configured.

The tank side plate 3 has a thickness of, for example, 4.5 m.
m. The lower portion of the tank side plate 3 is joined to the upper peripheral portion of the bottom plate 2 by fillet welding (6) on both sides,
The leg length of the fillet weld (6) is about 4.5 mm. The upper part of the tank side plate 3 is joined to the lower part of the top angle 4 by butt welding (7) or fillet welding (not shown).

Further, the roof plate 5 has, for example, a thickness of 4.
It is composed of a 5 mm plate and has a gradient of about 1/5 to 1/6. The peripheral end of the roof plate 5 is joined to the upper part of the top angle 4 by one-side fillet welding (8), and the leg length of the fillet welding (8) is about 4.5 mm. In addition,
The leg length mentioned above means the distance from the root of the joint to the toe of the fillet weld, as defined in JIS Z 3001, and, in flat terms, means the width of the fillet weld line.

The size of the top angle 4 is L50.
× 50 × 6 or L65 × 65 × 6 is commonly used.

[0006]

By the way, such existing small tanks have the following problems. That is, with use and operation for a long period of time, the inner and outer surfaces of the tank side plate 3 are corroded, and the thickness of the plate is reduced.

[0007] For this reason, the horizontal force and the vertical force at the time of the occurrence of an earthquake increase the vertical stress of the tank side plate 3, which may cause deformation and breakage of the side plate. Meanwhile, in recent years,
There is an increasing demand for storing hazardous and combustible materials using small tanks. However, when dangerous goods are stored using existing small tanks,
When the tank internal pressure rises abnormally, the welded part of the roof plate 5 breaks and releases the internal pressure, and the part except the roof plate 5 of the tank does not break, and the dangerous substance liquid leaks from the tank. Explosive structures are required to ensure that they do not occur.

However, such conventional explosive structures are not considered in existing small tanks. That is, as described above, the size of the top angle 4 at the top of the tank side plate 3 is L50 × 50 × 6 or L65 × 65.
× 6, and the slope of the roof plate 5 is about 1/5 to 1/6, while the lower portion of the tank side plate 3 is joined to the peripheral portion of the upper surface of the bottom plate 2 by fillet welding on both sides (6).

In such a structure, when the structure of the roof plate 5 and the top angle 4 portion is compared with the structure of the lower portion of the tank side plate 3, the strength of the lower portion of the tank side plate 3 is as follows.
The strength is lower than the strength of the roof plate 5 and the top angle 4 portion, and furthermore, the strength of the welded portion between the tank side plate 3 and the bottom plate 2 tends to decrease due to corrosion. Lower tank side plate 3 lower part,
In other words, there is a risk that the portion of the tank other than the roof plate 5 will be destroyed and the dangerous substance liquid will leak from the tank, and the explosion release structure is insufficient.

As described above, in the existing small tank,
As a tank for storing dangerous and combustible materials, it is hard to say that it is safe because of its explosive structure. The present invention has been made in view of the above-described conventional problems, and it is possible to avoid the possibility of side plates being deformed or damaged at the time of an earthquake, and to store flammable or dangerous materials. It is an object of the present invention to provide a method for reinforcing the strength of an existing tank that can have a structure.

[0011]

That is, the invention according to claim 1 comprises a bottom plate mounted or fixed on a foundation, a tank side plate welded and fixed to the bottom plate, and a tank side plate welded and fixed to an upper portion of the tank side plate. A top plate member, and a roof plate welded and fixed to an upper portion of the top plate member. A method of reinforcing the strength of an existing tank, comprising: % Or more, weld both sides of the angle iron to the outer peripheral surface of the tank side plate.
An angle iron side plate fixing step of fixing the angle iron to the outer peripheral surface of the tank side plate in a substantially vertical direction, and before the angle iron side plate fixing step,
Alternatively, before attaching the angle iron in contact with the bottom plate to the tank side plate in the middle of the angle iron side plate fixing step, the upper surface level of the bottom plate is substantially at the outer end position of the bottom plate corresponding to the disposition position of the angle iron. The same plate installation step of welding and installing on a foundation in the same manner, and at least after the said plate installation step, the lower part of the angle iron is welded to the bottom plate and the upper surface of the same plate, and the angle iron plate fixing step of welding. (Performed in any order) including fixing the angle irons at a plurality of positions spaced at a predetermined pitch along the circumferential direction of the outer peripheral surface of the tank side plate.

The top plate member and the angle iron must not be welded. In this specification, the height of the tank side plate is based on the upper surface of the bottom plate and does not include the size of the top plate member. The invention according to claim 2 is characterized in that, when the flammable liquid is stored in the tank, at least before the angle steel side plate fixing step, the tank side plate includes a water replacement step of replacing the liquid in the tank with water. The angle iron is fixed at a plurality of positions spaced at a predetermined pitch along the circumferential direction of the outer peripheral surface.

According to a third aspect of the present invention, the two side edges of the angle iron are fixed to the tank so that the step of fixing the angle steel side plate is at least 70% or more of the height of the tank side plate with respect to the upper surface of the bottom plate. The angle iron is welded to the outer peripheral surface of the side plate, and the angle iron is fixed to the outer peripheral surface of the tank side plate in a substantially vertical direction.

According to a fourth aspect of the present invention, the two side edges of the angle steel are fixed to the tank so that the step of fixing the angle steel side plate is at least 80% or more of the height of the tank side plate with respect to the upper surface of the bottom plate. The angle iron is welded to the outer peripheral surface of the side plate, and the angle iron is fixed to the outer peripheral surface of the tank side plate in a substantially vertical direction.

According to a fifth aspect of the present invention, in the angle steel side plate fixing step, the upper plate member has a height of 150 mm below a vertex.
Is characterized in that both side edges of the angle iron are not welded to the outer peripheral surface of the tank side plate. The invention according to claim 6 is characterized in that, in the angle steel side plate fixing step, both side edges of the angle iron are not welded to the outer peripheral surface of the tank side plate in a range of 300 mm below the top of the top plate member.

The invention according to claim 7 is that, in the angle steel side plate fixing step, a triangle is formed by the angle iron and the tank side plate so that both side edges of the equal angle angle steel are formed.
It is characterized in that it is welded to the outer peripheral surface of the tank side plate 3. In the invention according to claim 8, in the angle steel side plate fixing step,
Both side edges of the angle iron are continuously welded to the outer peripheral surface of the tank side plate.

According to a ninth aspect of the present invention, an upper opening of the angle iron is provided after the angle iron side plate fixing step or after the uppermost angle iron is attached to the tank side plate during the angle iron side plate fixing step. The step includes a lid fixing step of welding and fixing a plate closing the opening, wherein the angle irons are fixed at a plurality of positions spaced at a predetermined pitch along the circumferential direction of the outer peripheral surface of the tank side plate.

According to a tenth aspect of the present invention, the method further comprises the step of fixing the aforesaid plate on the foundation with an anchor bolt after the aforesaid plate installing step, the method comprising the steps of: The angle irons are fixed at a plurality of positions separated from each other. The operation of the invention will be described.

According to the first aspect of the present invention, by taking the respective steps, it is possible to withstand even when the vertical stress of the tank side plate increases due to the horizontal force and the vertical force at the time of the occurrence of the earthquake. It is possible to avoid the possibility of deformation or breakage of the tank side plate, etc., and to weld the plate to each of a plurality of outer end positions of the bottom plate corresponding to the positions of the plurality of angle irons on the tank side plate, and In addition to being installed on the foundation, the lower portions of the angle irons are welded to the bottom plate at the positions corresponding to the positions of the angle irons and the upper surface of the plate, so that the joint between the tank side plate and the bottom plate is welded. The bonding strength can be increased.

In the invention according to claim 2, by replacing the liquid in the tank with water, the reinforcement work can be started without cleaning the inside of the tank. According to the third and fourth aspects of the invention, the strength of the tank side plate is further improved by fixing the angle iron to the tank side plate outer peripheral surface to a predetermined height in a substantially vertical direction with the upper surface of the bottom plate as a base point.

In the invention according to claims 5 and 6,
A predetermined range below the top of the top plate member, by not welding both side edges of the angle iron to the tank side plate outer peripheral surface,
If the tank internal pressure rises abnormally for any reason, the welded part of the roof shingle breaks and releases the internal pressure,
An explosion-proof structure in which the part of the tank other than the roof panel is not destroyed is more reliably secured.

In the invention according to claim 7, the triangle is formed by the angle iron and the tank side plate, so that the strength of the tank side plate is further improved. In the invention according to claim 8, since the both side edges of the angle iron are continuously welded to the outer peripheral surface of the tank side plate, the strength of the tank side plate is further improved as compared with intermittent welding.

According to the ninth aspect of the present invention, by closing the upper opening of the angle iron with the plate, it is possible to prevent rainwater or the like from entering the space between the angle iron and the tank side plate from the opening. You. In the invention according to claim 10, the fixing strength of the joint plate between the tank side plate and the bottom plate is further increased by fixing the plate on the foundation with the anchor bolt.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings. An embodiment of a method for reinforcing the strength of an existing tank according to the present invention will be described using an existing small tank as an example.
Note that the same components as those shown in the conventional example are denoted by the same reference numerals and description thereof is omitted.

1 to 3, the method of reinforcing the strength of the existing small tank as shown in FIG.
[3] The equilateral angle steel 9 is fixed at a plurality of positions spaced at a predetermined pitch along the circumferential direction of the outer peripheral surface of the tank side plate 3 including the step. [1] Both sides of the equilateral angle iron 9 are welded (11) to the outer peripheral surface of the tank side plate 3 so that the height is at least 60% or more of the tank side plate 3 with the upper surface of the bottom plate 2 as a base point. Angle iron side plate fixing step of fixing the angle iron 9 to the outer peripheral surface of the tank side plate 3 in a substantially vertical direction. [2] An equilateral angle contacting the bottom plate 2 before the angle iron side plate fixing step or in the middle of the angle iron side plate fixing step. Before the steel 9 is attached to the tank side plate 3, the abutment plate 10 is attached to the bottom plate 2 corresponding to the planned or implemented position of the equilateral angle iron 9.
The upper plate level of the bottom plate 2 is welded (14) to the outer end position at substantially the same position, and the lower plate of the equilateral angle steel 9 is placed at least after the lower plate. In the above step [1], at least 60% or more of the tank side plate 3 with respect to the upper surface of the bottom plate 2, preferably, is welded to the upper surface of the bottom plate 2 and the upper plate 10. The equilateral angle steel 9 is placed in a substantially vertical direction so as to have a height of 70% or more, more preferably 80% or more.
Fix to the outer peripheral surface.

The top angle 4 and the equilateral angle steel 9 must not be welded. Further, in the range of 150 mm below the apex of the top angle 4, more preferably in the range of 300 mm below the apex of the top angle 4, it is preferable not to weld both side edges of the equilateral angle iron 9 to the outer peripheral surface of the tank side plate 3. Therefore, since it is meaningless if the equilateral angle steel 9 is present beside the top angle 4, it is preferable to mount the equal angle angle steel 9 to the tank side plate 3 so that the top of the equal angle angle steel 9 does not reach the top angle 4.

It should be noted that the tank side plate 3 does not include the top angle 4, so the height of the tank side plate 3 is the height from the upper surface of the bottom plate to the position just before the top angle 4. Further, the equilateral angle iron 9 is L50 × 50 × 6.
~ L150 × 1 50 × 10, preferably L65 × 65
It is preferable to use × 6 to L75 × 75 × 9. The equilateral angle iron 9 may be added and fixed to the tank side plate 3 by welding. In this case, the equilateral angle irons 9 to be added are added by continuous welding. In this refilling operation, a new equilateral angle steel 9 may be added to the equilateral angle steel 9 welded and fixed to the tank side plate 3 by the side of the tank side plate 3, or the equilateral angle iron may be welded to the tank side plate 3 before welding. The steels 9 may be added together and made to have a predetermined length, and then welded and fixed to the tank side plate 3, and any addition method may be used.

The steps [1] to [3] are repeated to fix the equilateral angle irons 9 at a plurality of positions spaced at a predetermined pitch along the circumferential direction of the outer peripheral surface of the tank side plate 3. That is, the steps [1] to [3] are performed at each position where the equilateral angle steel 9 is fixed at a predetermined pitch. [1] to [3] above performed at each position for fixing the equilateral angle iron 9
There are many procedures for the step. For example, the following cases are cited.

[2] → [1] → [3] ・ [2] → [3] → [1] ・ [2] → [1] halfway → [3] → [1] remaining ・ [1] halfway → [2] → [1] remaining → [3] ・ [1] halfway → [2] → [3] → [1] remaining Logically, in addition to the above, [2] halfway or [3] halfway It is conceivable that the procedure of the process is infinite.

Therefore, when considering the entire plurality of positions for fixing the equilateral angle steel 9, the above steps [1] to [3]
Since it is not necessary to proceed simultaneously, there are many procedures of the steps, and it can be said that the steps [1] to [3] can be substantially performed in any order. The predetermined pitch at which the equilateral angle irons 9 are arranged along the circumferential direction of the outer peripheral surface of the tank side plate 3 is 300 to 1500 mm, preferably 500 to 800 m.
m.

In the present invention, it is more preferable to adopt the following mode. That is, when a flammable liquid such as a dangerous substance is stored in the tank, at least before the step [1], preferably preparation before executing the three steps [1] to [3]. It is preferable to include a step of replacing the liquid in the tank with water at the stage, since the washing of the tank can be omitted. In this case, it is preferable that the water be applied to the roof portion above the level of the top angle 4 (top plate member), preferably about 50 mm above the top angle 4.

When water replacement is not performed, it is necessary to remove the combustible liquid from the tank as usual, and then wash the inside of the tank with a cleaning liquid to remove combustible substances. When the equilateral angle iron 9 is fixed to the outer peripheral surface of the tank side plate 3 by welding, a triangle is formed by the equal angle angle steel 9 and the tank side plate 3 as shown in FIG. Is preferably continuously welded to the outer peripheral surface of the tank side plate 3 (11).

A notch 16 is preferably provided at the lower end of the equilateral angle iron 9 on the tank side plate 3 side. As a result, drainage is improved and periodic leak inspection near the fillet weld (6) between the bottom plate 2 and the tank side plate 3 is facilitated. Further, both side edges of the equilateral angle iron 9 and the tank side plate 3 Welding with the outer peripheral surface (11) and welding between the lower part of the equilateral angle steel 9 and the upper surface of the abutment plate (15) can be prevented from intersecting, and the reliability of welding is improved.

After the [1] angle iron side plate fixing step or after the [1] angle iron side plate fixing step, the uppermost equal angle iron 9 is attached to the tank side plate 3, the upper part of the equal angle iron 9 is removed. A plate 12 (for example, a plate thickness of 4.5 mm) that closes the opening 9A is welded and fixed to the opening 9A, and rainwater or the like flows from the opening 9A into the space between the equilateral angle iron 9 and the tank side plate 3. Preferably, it can be prevented from entering.

Further, after the step (3), the contact plate is preferably fixed on the foundation 1 with anchor bolts 13. The work may be performed at any time after the plate 10 is welded (14) to the outer end of the bottom plate 2. As described above, the two side edges of the equilateral angle iron 9 are welded to the outer peripheral surface of the tank side plate 3 at a plurality of positions spaced at a predetermined pitch along the circumferential direction of the outer peripheral surface of the tank side plate 3, respectively. 9 is fixed to the outer peripheral surface of the tank side plate 3 in a substantially vertical direction with the base plate 3 as a base point, so that the strength of the tank side plate 3 can be increased. The buckling strength of the tank side plate 3 can be increased by welding and fixing 9.

Accordingly, even when the vertical stress of the tank side plate 3 increases due to the horizontal force and the vertical force at the time of the occurrence of the earthquake, the tank side plate 3 can withstand the stress, and the tank side plate 3 is deformed or damaged. The fear can be avoided. Further, the contact plate 10 is welded and fixed to a plurality of positions on the outer end of the bottom plate 2 corresponding to the positions of the plurality of equilateral angle steels 9 on the tank side plate 3, and is installed on the foundation 1. The lower part of the steel 9 is welded to the upper surface of the bottom plate 2 and the upper surface of the abutment plate 10 at the positions corresponding to the positions where the plurality of equilateral angle irons 9 are provided, respectively, so that the joint strength of the joint between the tank side plate 3 and the bottom plate 2 is reduced. Can be enhanced.

Therefore, the roof plate 5 and the top angle 4
When the structure of the lower part of the tank side plate 3 is compared with the structure of the lower part of the tank side plate 3, the strength of the lower part
When the pressure inside the tank rises and the strength of the top angle 4 part increases, the roof plate 5 and the top angle 4 part which are lower in strength are broken, and the internal pressure is released,
It is possible to provide a reliable explosion release structure in which dangerous substance liquid does not leak from the tank.

That is, since the existing small-size tank reinforced with the strength becomes safe from the explosion release structure, safety can be ensured, and even combustible materials and dangerous materials can be stored. In the above-described embodiment, the strength reinforcing method of the present invention has been described by taking an existing small tank as an example. However, the present invention is not limited to a small tank and can be applied to other tanks.

In the above embodiment, the equilateral angle steel 9 is attached to the tank side plate 3, but the unequal angle angle steel may be used.

[0040]

As described above, according to the first aspect of the present invention, the strength of the tank side plate of the existing tank, particularly the buckling strength, can be increased, and the joint portion between the tank side plate and the bottom plate can be improved. As a result of being able to increase the bonding strength, it is possible to avoid the risk of deformation or breakage of the side plate at the time of the occurrence of an earthquake, and to provide an explosive structure capable of storing even flammable and dangerous materials.

In the invention according to the second aspect, reinforcement work is performed without cleaning the inside of the tank. In the invention according to claims 3 and 4, the strength of the tank side plate can be further improved. In the invention according to claims 5 and 6, when the tank internal pressure rises abnormally for any reason, the welded portion of the roof shingle is broken to release the internal pressure, and the portion of the tank other than the roof shingle is removed. A detonation structure that does not destroy can be more reliably secured.

In the invention according to claim 7, the strength of the tank side plate can be further improved. According to the invention according to claim 8, the strength of the tank side plate can be further improved. According to the ninth aspect of the present invention, it is possible to prevent rainwater or the like from entering the space between the angle iron and the tank side plate from the upper opening of the angle iron. According to the tenth aspect, the joint strength of the joint between the tank side plate and the bottom plate can be further increased.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a small tank for explaining an embodiment of a method for reinforcing the strength of an existing tank according to the present invention.

FIG. 2 is a view taken in the direction of arrow A in FIG.

FIG. 3 is a view showing the entire structure of the small tank according to the first embodiment;
(A) is a front view, (B) is a plan view

FIG. 4 is a longitudinal sectional view showing the structure of a conventional existing small tank.

[Description of Signs] 1 Foundation 2 Bottom plate 3 Tank side plate 4 Top angle 5 Roof plate 9 Equal angle angle steel 10 Applicable plate 13 Anchor bolt

Continuation of front page (56) References JP-A-59-51083 (JP, A) JP-A-57-30500 (JP, U) JP-A-55-88984 (JP, U) JP-A-52-11617 (JP) , U) Japanese Utility Model Showa 62-31098 (JP, U) Japanese Utility Model Showa 64-43296 (JP, U) Japanese Utility Model Showa 56-18379 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB Name) B65D 88/00-90/66

Claims (10)

(57) [Claims] 1. A bottom plate installed or fixed on a foundation, a tank side plate welded and fixed to the bottom plate, a top plate member welded and fixed to an upper portion of the tank side plate, and a top plate member welded to the upper portion of the top plate member A fixed roof plate, comprising: a reinforcing plate for reinforcing an existing tank, the reinforcing plate comprising: an upper surface of the bottom plate, and a height of at least 60% of the tank side plate. An angle steel side plate fixing step of welding an edge portion to the tank side plate outer peripheral surface and fixing the angle iron to the tank side plate outer peripheral surface in a substantially vertical direction; and before the angle iron side plate fixing step, or before fixing the angle iron side plate Before attaching the angle steel in contact with the bottom plate to the tank side plate in the middle of the process, this plate is welded to the outer end position of the bottom plate corresponding to the position where the angle steel is disposed, so that the upper surface level of the bottom plate is substantially the same. This plate installation process to be installed on At least after the contact plate installing step, fixing a lower part of the angle iron to the upper surface of the bottom plate and the contact plate, and fixing an angle steel contact plate. A method of reinforcing the strength of an existing tank, comprising fixing angle irons at a plurality of positions separated by a pitch. 2. When the flammable liquid is stored in the tank, at least before the step of fixing the angle steel side plate, a water replacement step of replacing the liquid in the tank with water is performed. 2. The method for reinforcing the strength of an existing tank according to claim 1, wherein the angle irons are fixed at a plurality of positions spaced at a predetermined pitch along the circumferential direction. 3. The angle steel side plate fixing step includes welding both side edges of the angle iron to the outer peripheral surface of the tank side plate so that the height is at least 70% or more of the tank side plate with respect to the upper surface of the bottom plate. The method for reinforcing the strength of an existing tank according to any one of claims 1 to 2, wherein the angle iron is fixed to the outer peripheral surface of the tank side plate in a substantially vertical direction. 4. The angle steel side plate fixing step includes welding both side edges of the angle iron to the outer peripheral surface of the tank side plate so that the height is at least 80% or more of the tank side plate with respect to the upper surface of the bottom plate. The method for reinforcing the strength of an existing tank according to any one of claims 1 to 2, wherein the angle iron is fixed to the outer peripheral surface of the tank side plate in a substantially vertical direction. 5. In the angle steel side plate fixing step, both side edges of the angle iron are not welded to the outer peripheral surface of the tank side plate within a range of 150 mm below the top of the top plate member. The method for reinforcing the strength of an existing tank according to any one of the above. 6. The angle plate steel side plate fixing step, wherein both side edges of the angle iron are not welded to the outer peripheral surface of the tank side plate within a range of 300 mm below the top of the top plate member. The method for reinforcing the strength of an existing tank according to any one of the above. 7. In the angle steel side plate fixing step, both sides of the equal angle angle iron are welded to the outer peripheral surface of the tank side plate 3 such that a triangle is formed by the angle iron and the tank side plate. Any one of claims 1 to 6,
The method for reinforcing the strength of existing tanks described in 1. 8. The method according to claim 1, wherein, in the angle steel side plate fixing step, both side edges of the angle iron are continuously welded to the outer peripheral surface of the tank side plate. Strengthening method of existing tank. 9. An opening at an upper portion of the angle iron, after the angle iron side plate fixing step or after the uppermost angle iron is attached to the tank side plate during the angle iron side plate fixing step. The angle iron is fixed at a plurality of positions separated at a predetermined pitch along the circumferential direction of the outer peripheral surface of the tank side plate, including a lid fixing step of welding and fixing the plate closing the plate. The method for reinforcing the strength of an existing tank according to any one of the first to third aspects. 10. A method according to claim 10, further comprising the step of fixing said plate on said foundation by anchor bolts after said step of setting said plate, at a plurality of positions separated at a predetermined pitch along the circumferential direction of the outer peripheral surface of the tank side plate. The method for reinforcing the strength of an existing tank according to any one of claims 1 to 9, wherein the angle iron is fixed.