JPS583158B2 - Thin film type low temperature liquefied gas tank - Google Patents

Description

Detailed Description of the Invention The present invention provides a thin-film type low-temperature liquefied gas for storing so-called low-temperature liquefied gas, which is obtained by liquefying substances that are gaseous at normal temperature, such as natural gas and petroleum gas, at approximately normal pressure. related to tanks.

The structure of this type of tank generally consists of a rigid outer shell,
A heat insulating layer provided inside the outer shell, and a thin-film inner tank provided inside the outer shell, that is, an inner tank made of thin plates that easily bends due to internal pressure and comes into close contact with the inner surface of the heat insulating layer. However, although this inner tank does not have sufficient plate thickness to withstand internal pressure, it includes a so-called semi-thin membrane type inner tank that has a plate thickness that allows it to substantially stand on its own when no internal pressure is applied at room temperature.) The internal pressure exerted by the low-temperature liquefied gas filled in the inner tank is transmitted to the outer shell via the heat insulating layer, and the inner pressure is taken care of by the outer shell.

In this case, the thin film inner tank is subjected to thermal stress when changing from a normal temperature unloaded state to a low temperature unloaded state to a low temperature loaded state, or vice versa, as the low temperature liquefied gas is loaded or discharged. , thereby performing complex transformations.

Therefore, such a thin film inner tank has conventionally been constructed to a size that includes an amount of surplus approximately equal to the amount of shrinkage at low temperatures, and this surplus is used to absorb the shrinkage when loading low-temperature liquefied gas. Stress concentration is avoided by not applying a restraining force to the inner tank itself that should prevent deformation due to thermal stress.

In order to provide a surplus to the thin film inner tank, it is sufficient to make the inner tank larger in advance by the surplus, but in addition to this, it is also possible to make the inner tank larger in the vertical direction (height direction).
BACKGROUND OF THE INVENTION Thin-film inner tanks have been known in the past, in which the inner tank is constructed of a thin plate with a collage extending over the inner tank, thereby providing a surplus to the inner tank.

In this case, the outer circumferential surface of the thin film inner tank is in contact with the inner circumferential surface of the heat insulating layer in a substantially slidable manner even under normal temperature and no-load conditions, including during construction, etc., and the outer circumferential surface of the thin film inner tank is in contact with the inner circumferential surface of the heat insulating layer in a substantially slidable manner, and the inner circumferential surface of the thin film inner tank is in contact with the inner circumferential surface of the heat insulating layer in a substantially slidable manner, and in the circumferential direction and height direction. It is in a state where it can move completely freely without being restricted in any way.

However, especially in the case of a thin film inner tank with vertically extending collage, the thermal deformation is absorbed by the collagen, so the thin film inner tank is useful for uniformizing the movement of the collage, preventing deformation in the circumferential direction, and building construction. From the viewpoint of welding workability during welding, etc., it is preferable that the welding member is slidably locked only in the vertical direction at a plurality of points spaced apart in the circumferential direction.

An object of the present invention is to provide a thin-film type low-temperature liquefied gas tank proposed based on the above-mentioned viewpoints.

According to the present invention, such a purpose is to provide a thin-film type low-temperature liquefied gas tank comprising an outer shell having a rigid structure, a compression-resistant heat insulating layer provided inside the shell, and a thin film inner layer further provided inside the shell. In this case, concave grooves extending substantially perpendicularly to the inner circumferential surface of the vertical wall portion of the heat insulating layer are provided at intervals in the circumferential direction, and the thin inner layer is formed by bonding a plurality of constituent plates. a component plate configured such that both side edges of the component plate are bent substantially perpendicularly outward to form folded pieces, each of the folded pieces being adjacent to each other at a connecting portion of each of the constituent plates; The corner portions of the bent pieces overlapped with each other and adjacent to each other are welded together to form a protruding piece that extends substantially vertically, and each of the protruding pieces slides into the groove in the longitudinal direction thereof. This is achieved by a thin-film tank for low-temperature liquefied gas, which is characterized in that it is freely engaged.

The attached FIG. 1 is a longitudinal sectional view of a tank for low-temperature liquefied gas according to the present invention, FIG. 2 is an enlarged sectional view taken along the line ■-■ in FIG. 1, and FIG. FIG. 4 is an enlarged sectional view showing details, and a perspective view showing the tank wall structure shown in FIG. 2.

In these figures, 1 is a rigid outer shell;
is constructed of concrete, etc., and a portion of it is buried underground.

A heat insulating layer 2 with a compression-resistant structure is provided inside the outer shell 1, and a metal roof structure 3 is arranged on the upper part of the outer shell 1 to close the upper opening in an air-liquid tight state. ing.

Note that a roof heat insulating layer 4 is also provided inside the roof structure 3.

In this embodiment, the heat insulating layer 2 is as follows. It is constructed of a frame body 5 made of a wooden frame or the like, with a heat insulating material 6 such as powdered perlite or glass wool filled between the frames.

Further, a plurality of rectangular face plywood boards 7 are pasted on the inner peripheral surface of this heat insulating layer 2. In this case, each face plywood board 7 is pasted to each other with a predetermined gap in the lateral direction, and each of the gaps vertical direction (
A concave groove 9 extending in a straight line in the tank height direction is defined.

Therefore, the grooves 9 are provided at intervals in the circumferential direction for each sheet of face plywood 7.

Inside the heat insulating layer 2 whose inner peripheral surface is defined by the face plywood 7, there is provided a suspended inner tank 10 having a thin film structure made of a low temperature resistant material such as a nickel steel plate or an aluminum plate.

This inner tank 10 includes a flat bottom plate portion 10a placed on the bottom plate of the heat insulating layer 2, and a vertical wall portion 10c connected via a curved corner portion 10b continuous to the outer peripheral edge of the bottom plate portion 10a.
The vertical wall portion 10C is suspended from the roof structure 3 via a hanging member 11.

The vertical wall portion 10c is composed of a plurality of rectangular vertical wall constituent plates M each formed with a plurality of vertically extending corrugations c, which are joined together by welding. Both side edges are bent substantially perpendicularly to one side (outside), and each of these folded pieces connects the folds of the adjacent constituent plates M at the connecting parts (joining parts) of each constituent plate M. It overlaps with the bent piece and is welded to each other at the base (see FIG. 3), forming a substantially vertically extending projecting piece 12.

Each of the projecting pieces 12 engages with the groove 9 in a slidable manner in the longitudinal direction thereof.

In this case, it is necessary to use the component board M and the face plywood 7 having the same width.

Next, a procedure for constructing a thin-film type low-temperature liquefied gas tank having the above-described structure will be explained.

(l) Execute outer shell 1 (2) A heat insulating layer 2 is applied to the inner peripheral surface of the outer shell 1.

At this point, substantially vertically extending grooves 9 are provided at circumferentially spaced intervals on the inner circumferential surface of the vertical wall thereof.

(3) Collagation and bending of the side edges are performed on a thin plate material (vertical wall component plate) M having a width of about 1 to 1.5 m.

(4) Assemble the bent piece of the thin plate material processed in step (3) onto the inner circumferential surface of the vertical wall of the heat insulating layer 2 while inserting it into the groove 9 provided in the heat insulating layer 2.

(5) In step (4), tack welding is performed on the joints of the thin plate materials arranged along the inner peripheral surface of the vertical wall portion of the heat insulating layer 2.

(6) Perform main welding of the seam portion.

TIG welding, plasma welding, etc. are suitable for this main welding.

(7) Repeat steps (4) to (6), and
0 vertical wall portion 10c is completed.

(8) Lay the flat bottom plate portion 10a of the thin film inner tank 10 on the bottom plate of the heat insulating layer 2.

When the vertical wall portion 10c and the flat bottom plate portion 10a of the inner tank are completed, the bottom plate portion 10a of the inner tank and the corner portion are welded together.

When welding thin plate materials, depending on the material of the heat insulating layer, asbestos paper or the like may be pasted on the groove to protect it from welding heat.

Figures 5-6 show another embodiment of the invention, in which the insulation layer 2 is made of a material such as a rigid polyurethane foam which is itself compression resistant and does not require a frame. It is configured.

In this case, the groove 9 may be provided directly on the inner peripheral surface of the vertical wall portion of the heat insulating layer 2.

As described above, according to the present invention, since the thin plate material with a width of about 1 to 1.5 m is inserted into the groove of the heat insulation layer and assembled, the movement of the extra length of the collage in each area can be made uniform. It is also possible to equalize the movement of each thin plate material during a pressure test, and avoid unexpected deformation of the thin plate inner tank.

In addition, deformation of the thin plate in the circumferential direction can be prevented, and the verticality of the vertical wall of the inner tank has good verticality, making it easier to perform welding between the vertical wall of the inner tank and the bottom plate of the inner tank than in the past. can.

Furthermore, when constructing the inner tank, each thin plate material is inserted into a groove and temporarily fixed to the heat insulating layer, so it is necessary to use special jigs for welding to connect the thin plate materials. Without,
This can be done easily and reliably.

In the above-described embodiment, the protruding piece was inserted into the groove of the heat insulating layer when welding the inner tank, but the present invention is not limited to this. You can also insert it into the groove.

In this case as well, it is possible to equalize the movement of the collage of each constituent plate.

Although the present invention has been described in detail with respect to specific embodiments above, it is understood that the present invention is not limited to these embodiments only, and that various embodiments are possible within the scope of the present invention. will be clear to those skilled in the art.

[Brief explanation of drawings]

Figure 1 is a longitudinal cross-sectional view showing one embodiment of a thin film type low temperature liquefied gas tank according to the present invention, and Figure 2 is a vertical sectional view showing the line 1 of Figure 1.
3 is an enlarged sectional view showing the details of the arrow A in FIG. 2, FIG. 4 is a perspective view showing the tank wall structure shown in FIG. 2, and FIG. FIG. 6 is a cross-sectional view showing an embodiment of the thin-film type low-temperature liquefied gas tank according to the present invention;
The figure is a perspective view thereof. 1... Outer shell, 2... Heat insulation layer, 3...
... Roof structure, 4 ... Roof insulation layer, 5.
... Frame body, 6 ... Insulation material, 7 ...
・Face plywood, 8... Backing plate, 9... Concave groove, 10... Thin film inner tank, 11... Hanging member, 12... ...Protruding piece, M... Vertical wall component plate (thin plate material).

Claims (1)

[Claims] 1. In a thin film type low temperature liquefied gas tank comprising a rigid outer shell, a compression-resistant heat insulating layer provided inside the shell, and a thin film inner layer provided inside the shell, the heat insulating layer is Recessed grooves extending substantially perpendicularly to the inner circumferential surface of the vertical wall portion are provided at intervals in the circumferential direction, and the thin film inner layer is formed by joining a plurality of constituent plates, and the inner circumferential layer is formed by joining a plurality of constituent plates, and the inner circumferential layer is formed by joining a plurality of constituent plates. the edges are bent substantially vertically outwardly to form folded pieces, each folded piece overlapping a folded piece of an adjacent constituent plate at the junction of each said constituent plate; The corner portions of adjacent bends are welded to each other to form a substantially vertically extending protruding piece, and each of the protruding pieces is engaged with the groove so as to be slidable in the longitudinal direction thereof. A thin-film type low-temperature liquefied gas tank characterized by: