JP3237724B2 - Suspension structure of internal turning ladder of low temperature storage 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 suspension structure for an internal turning ladder of a low-temperature storage tank, which can safely support a turning ladder permanently installed in the low-temperature storage tank while interrupting the transmission of cold heat at a low temperature. is there.

[0002]

2. Description of the Related Art A low-temperature storage tank for storing a low-temperature liquid such as LPG (liquefied petroleum gas) or LNG (liquefied natural gas) has a protective wall integrated with a tank body for preventing a leak in case of a leak. Some use an outer tank, and there are two types: an above-ground type, in which the entire tank is installed on the ground, and an underground type, in which the tank body is buried underground and only the roof is positioned on the ground.

Conventionally, in a low-temperature storage tank using such a concrete outer tank, a suspended ceiling (suspended deck) is provided inside a roof that covers the upper part of the concrete outer tank, and a cold insulator is attached to the suspended ceiling to cool the roof. It is being done that the roof itself is constructed of room temperature wood.

[0004] In recent years, it has been considered to adopt a cooling method for a roof inner surface in which a roof is constructed of a low-temperature material and a cooling material is attached to the inner surface of the roof.

[0005] When such a roof inner surface cooling structure is used, the cost is increased due to the construction of the roof with low-temperature materials, so it is necessary to reduce the cost by reducing the weight, and it is necessary to make the roof bones as thin as possible. It is necessary to keep the outer surface of the roof free of frost by using insulation.

[0006] On the other hand, when checking the cooling material on the inner surface of the roof, a temporary scaffold is required, but it is difficult to temporarily install it in the tank after construction, and a permanent turning ladder is mounted inside the roof. It is possible.

[0007]

In developing such a turning ladder, there are various problems to be solved.

For example, when an annular rail that supports the base end of the turning ladder at the center of the roof and allows the turning end of the turning ladder to be mounted, it is necessary to prevent the transmission of cold heat, and the strength and prevention of frost adhesion are required. In order to achieve both, a hollow cylindrical support having a small cross-sectional area must be used.

On the other hand, if the low-temperature liquid is stored in a state where the turning ladder is permanently installed, the turning ladder, the annular rail and the like are thermally contracted. It is necessary to provide a heat shrink absorbing structure by, but if this heat shrink absorbing structure is provided at both ends of the support,
The annular rail is not fixed, and moves along with the turning of the turning ladder, so that turning of the turning ladder becomes impossible, and there is a problem that the turning ladder swings and work becomes difficult.

Further, even if the heat shrinkage absorbing structure is provided, if a large frictional force is generated between the slot and the pin by the load of the turning ladder, the heat shrinkage is not absorbed, and the support may be damaged due to a bending load applied. is there.

Therefore, if the size of the roof bones and supports is increased to improve the strength, the weight and cost of the roof are increased, and the heat is easily transmitted.

On the other hand, when the fixed position of the turning ladder for storing in a low temperature state is determined and only the support of that portion is strengthened, or if both ends are supported by pins so that a bending load is not applied, the supporting portion of the turning ladder is prevented. There is a problem in that the load distribution due to heat shrinkage changes, which adversely affects the support of other parts of the annular rail.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems associated with the development of such a turning ladder, and is directed to a low-temperature storage tank capable of safely supporting a turning ladder that is permanently installed in the low-temperature storage tank in a low-temperature state while blocking the transmission of cold heat. It is an object of the present invention to provide a suspension structure for an internal turning ladder.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, a cold insulator is attached to an inner surface of a roof, a base end is supported at a center of an upper portion of a storage tank for storing low-temperature liquid, and a ladder is turned along the inner surface of the roof. In the suspension structure of the internal turning ladder, the trolley traveling annular rail that supports the ladder tip to the roof bone is supported via a hollow cylindrical support that suppresses cooling and heat transfer, and a long hole is provided between these supports and the annular rail. And a heat shrink absorbing structure with pins, and a roof through a hollow cylindrical storage support that supports the load of the ladder to reduce frictional force when the ladder is stored at a low temperature and to enable movement by the heat shrink absorbing structure. The bone and the ladder are connected so that a bending load is not applied.

[0015]

According to the suspension structure of the internal turning ladder of the low-temperature storage tank, a hollow cylindrical support is attached to the roof bone to support the annular rail through the heat shrinkage absorbing structure of the long hole and the pin. Sometimes the ladder load is separately provided so that the heat shrinkage absorbing structure can move, and both ends are connected by pins etc. and supported by the storage support where bending load is not applied, and a large force is applied to the support that supports the annular rail The ladder can be safely supported inside the roof while blocking the transmission of cold heat at low temperatures.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. 1 to 5 show an embodiment of a suspension structure of an internal turning ladder of a low-temperature storage tank according to the present invention. FIG. 1 is a partially enlarged side view and a front view, and FIG. 2 is an overall side view and a plan view of the turning ladder. 3 is a support structure diagram of the annular rail, FIG. 4 is a detailed diagram of the support, and FIG. 5 is a detailed diagram of a base end portion of the turning ladder.

Hanging structure 1 of the internal turning ladder of this low-temperature storage tank
In FIG. 0, the base end of the turning ladder 12 is rotatably supported at the center of the tank roof 11, and the tip of the turning ladder 12 is suspended from a trolley 14 running along an annular rail 13 attached to the tank roof 11. It can be turned and lowered.

The tank roof 11 on which such a turning ladder 12 is installed is made of a low-temperature material, and has an internal cold insulation structure in which a cold insulator 15 is attached to the inner surface of the tank roof 11.

As shown in FIGS. 2 and 5, a hollow cylindrical support shaft 16 is fixed to the center of the tank roof 11 to support the base end of the turning ladder 12, and a circle is formed at the lower end of the support shaft 16. A plate-shaped central stage 17 is attached, and the periphery of the central stage 17 is fixed at regular intervals via a hollow cylindrical support 19 and a support rod 20 attached to a roof bone 18.

By using a hollow cylindrical support shaft 16 and support 19 for fixing the center stage 17,
The cross-sectional area is reduced while ensuring the strength, so that cold heat is prevented from being transmitted to the tank roof 11.

The mounting structure of the annular rail 13 mounted on the tank roof 11 to support the tip of the turning ladder 12 is such that the upper end of a hollow cylindrical support 21 is welded to the roof bone 18 as shown in FIG. At the lower end of the support 21, the annular rail 13 is inserted into the long hole 23 of the bracket 22.
The pin 25 attached to the bracket 24 is mounted and connected.
6.

The use of the hollow cylindrical support 21 also for the attachment of the annular rail 13 prevents transmission of cold heat as much as possible while ensuring strength. In addition, since the upper end of the support 21 is welded to the roof bone 18 and the heat shrinkage absorbing structure 26 is provided only at the lower end, the annular rail 13 can be held concentrically with the tank roof 11 and can swing greatly. , The trolley 14 can be prevented from becoming unable to travel.

In such a structure for supporting the turning ladder 12, the tank roof 11 itself needs to be constructed using a low-temperature material, so that the weight is reduced and a thin roof bone 18 is used. Supports 19 and 21
Are also formed using a hollow cylindrical tube having a small diameter.

The structure of these supports 19 and 21 is shown in FIG.
The fixed shaft 28 is welded to the mounting plate 27 that is welded to the roof bone 18, and the fixed plate 2 that is welded to the fixed shaft 28 as shown in FIG.
9, the flange 31 of the hollow cylindrical body 30 is locked.
2, a bracket 22 and the like are welded.

Therefore, even in the exposed state where the cooling material is not attached to the annular rail 13, the route through which the cold heat is transmitted to the roof bone 18 of the tank roof 11 depends on the bracket 24 → pin 25 → long hole 23 → bracket 22 → Flange 32 →
Since the hollow cylindrical body 30 → the flange portion 31 → the fixed plate 29 → the fixed shaft 28 → the mounting plate 27, the amount of transmitted cold heat is suppressed by the hollow cylindrical body 30 having a small cross-sectional area. Frost can be prevented.

Next, as shown in FIG. 2, the turning ladder 12 which is turnably supported via the center stage 17 and the annular rail 13 has a turning ring 33 which turns along the outer periphery of the center stage 17 and a step-like turning ring. And a ladder portion 35 having a floor plate 34 are integrally connected. Then, the turning ring 33 is placed on a horizontal roller 36 attached to the outer periphery of the central stage 17 and
7, so that the base end of the turning ladder 12 can turn.

The tip of the turning ladder 12 is shown in FIGS.
As shown in FIG. 5, the tank roof 1 is suspended by a chain 38 attached to two trolleys 14 that can travel along the annular rail 13.
1, the swivel ladder 12 can be swung.

In the suspension structure 10 of the internal turning ladder of the low-temperature storage tank, when a low-temperature liquid such as LNG (-162 ° C.) is stored in the tank, a low-temperature gas (−162 ° C. in LNG) substantially equal to the storage temperature is stored. ) Causes thermal contraction.

At the time of this heat shrinkage, the heat shrinkage absorbing structure 26 of the support 21 of the annular rail 13 in the portion where the turning ladder 12 is in a stopped state functions, and the pin 25 extends along the elongated hole 23.
Moves smoothly, the bending load is not applied to the support 21 and the turning ladder 12 can be supported as it is even in a low temperature state.

However, the long holes 23 of the heat shrinkage absorbing mechanism 26
The self-weight of the turning ladder 12 is applied between the pin 25 and the pin 25, and a large frictional force acts on the pin 25 along the slot 23.
Cannot move, and a large bending load may be applied to the support 21.

On the other hand, since the tank roof 11 is made of a low-temperature material as an internal cold insulation structure, it is necessary to reduce the weight. The roof bone 18 is also made thin, and the transmission of cold heat is prevented as much as possible to prevent frost formation. It is not possible to make the support 21 large so as to withstand the bending load because of the necessity to prevent it.

Therefore, a fixed position of the turning ladder 12 in a low temperature state is determined, and a suspension structure for separately supporting the own weight of the turning ladder 12 is provided.

As the suspension structure at the time of low temperature, a hollow cylindrical storage support 40 is attached to a thick ring 39 of the roof bone 18 of the tank roof 11, and the tip of the turning ladder 12 is suspended via a chain 41. .

The storage-time support 40 has a hollow cylindrical shape like the supports 19 and 21 described above so as to minimize the transmission of cold heat, and the specific structure is the same as that described with reference to FIG. Therefore, the description is omitted.

The storage support 40 and the chain 41
Since the turning ladder 12 is supported through
The storage support 40 can support the load of the turning ladder 12 so that only the tensile load is applied without the bending load.

Since the weight of the revolving ladder 12 is supported by the storage support 40 and the chain 41, the oblong hole 23 of the heat shrinkage absorbing structure 26 of the annular rail 13 is provided.
The frictional force between the pin and the pin 25 is reduced so that the relative movement can be smoothly performed.
Is prevented from being subjected to a bending load, and can be stored without trouble even in a low temperature state.

According to the present invention, the heat shrinkage absorbing mechanism 26 functions by supporting the load of the turning ladder 12 with the separately provided storage support 40, and two of the supports 21 of the annular rail 13 are provided. It is conceivable that the annular rail 13 has a similar function, but the support state of a part of the annular rail 13 is different, so that the load distribution due to the heat shrinkage becomes uneven, and the support 21 of the other part of the annular rail 13 is bent. The structure of the present invention is most suitable for storing the turning ladder at a low temperature, because a bad influence of a load or the like is exerted on the turning ladder.

The present invention is not limited to the suspension structure of the internal turning ladder of the underground tank for storing LNG, but may be applied to the suspension structure of the internal turning ladder of the underground tank for storing low-temperature liquid or the above-ground tank. it can.

Further, the present invention is not limited to the above-described embodiment, and each component may be changed without departing from the gist of the present invention.

[0040]

According to the suspension structure of the internal turning ladder of the low-temperature storage tank according to the present invention, as described above in detail with one embodiment, a hollow cylindrical support is attached to the roof bone and the long hole and the pin are connected to each other. Since the annular rail is supported via the heat shrink absorbing structure, and the ladder load is separately supported so that the heat shrink absorbing structure can move at the time of heat shrink, so that it is supported by the storage support where bending load is not applied, A large force can be prevented from being applied to the support for supporting the annular rail, and the turning ladder can be safely supported inside the roof while blocking the transmission of cold heat in a low temperature state.

[Brief description of the drawings]

FIG. 1 is a partially enlarged side view and a front view of a suspension structure of an internal turning ladder of a low-temperature storage tank according to an embodiment of the present invention.

FIG. 2 is an overall side view and a plan view of a turning ladder according to one embodiment of a suspension structure of an internal turning ladder of a low-temperature storage tank of the present invention.

FIG. 3 is a support structure diagram of an annular rail according to an embodiment of the suspension structure of the internal turning ladder of the low-temperature storage tank according to the present invention.

FIG. 4 is a detailed view of a support according to an embodiment of the suspension structure of the internal turning ladder of the low-temperature storage tank of the present invention.

FIG. 5 is a detailed view of a base portion of the turning ladder according to one embodiment of the suspension structure of the internal turning ladder of the low-temperature storage tank according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 Suspension structure of internal turning ladder of low-temperature storage tank 11 Tank roof 12 Turning ladder 13 Ring rail 14 Trolley 15 Cooling material 16 Support shaft 17 Central stage 18 Roof bone 19 Support 20 Support rod 21 Support 22, 24 Bracket 23 Long hole 25 Pin 26 Heat shrinkage absorbing mechanism 27 Mounting plate 28 Fixed shaft 29 Fixing plate 30 Hollow cylindrical body 31, 32 Flange part 33 Swivel ring 34 Floor plate 35 Ladder part 36 Horizontal roller 37 Vertical roller 38 Chain 39 Ring 40 Storage support 41 Chain

Continuation of the front page (72) Inventor Seishi Horiguchi 3-2-16-1 Toyosu, Koto-ku, Tokyo Ishikawa-jima-Harima Heavy Industries, Ltd. Toyosu General Office (56) References JP-A-63-138993 (JP, A) Opened 63-94253 (JP, U) Opened 58-73790 (JP, U) Opened 56-62988 (JP, U) Opened 5-66154 (JP, U) Opened 43-7463 (JP, U) JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B65D 88/00-90/20 F17C 1/00-13/12

Claims (1)

(57) [Claims] 1. A hanging structure of an internal turning ladder for supporting a base end at a center of an upper portion of a storage tank for storing a low-temperature liquid by attaching a cold insulator to a roof inner surface and turning a ladder along the roof inner surface, wherein a ladder tip is attached to a roof bone. The supporting trolley traveling circular rail is supported via hollow cylindrical supports that suppress the transfer of cold heat, and a heat shrinkage absorbing structure with long holes and pins is provided between these supports and the circular rail to store the ladder at low temperature. Sometimes, the roof bone and the ladder are connected via a hollow cylindrical storage support that supports the load of the ladder to reduce the frictional force and allow the heat shrinkage absorbing structure to move so that bending load is not applied. The suspension structure of the internal turning ladder of the low-temperature storage tank.