JPH0424599B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The disclosed technology is used for regular and non-regular applications to prevent unforeseen accidents such as cracks in spherical tanks used for storing gas such as propane gas. It belongs to the technical field of open inspection.

<Summary of the gist> The invention of this application is to fill the spherical tank body with water, purge the residual gas, and then remove the tank during regular or irregular opening inspections of spherical tanks for gas storage, etc. This invention relates to a method for inspecting a spherical tank, in which a work scaffold is installed inside the main body to perform non-destructive inspection, repair, painting, etc. on the tank main body, and an inspection device directly used in the method. In particular, after filling the spherical tank with water and purging the residual gas, the water level is first lowered to about 1.5 to 1.6 meters from the upper manhole, and materials for the floating scaffold are brought in through the upper manhole. is formed into a ring shape along the boundary between the water and the tank body, and a prefabricated connector or guard is attached to form a floating scaffold in the circumferential direction of the water surface, and predetermined inspection work is performed on the inner surface of the tank body. In this case, while lowering the water level, the number of floating scaffolds in the circumferential direction is increased using assembly materials, and in the process of lowering the water level, in which the circumferential length of the boundary between the tank body and the water surface is reduced, the floating bodies are sequentially disassembled into a ring shape. This invention relates to a method for inspecting a spherical tank, in which the floating scaffold is reduced and, after the water is finally discharged, the materials of the dismantled floating scaffold are taken out from a manhole at the bottom of the tank body, and a device for inspecting a spherical tank that is directly used for this method. be.

<Prior art> As is well known, in order to continuously supply a fixed amount of propane gas, etc. to demand customers, it is preferable to store a predetermined amount of gas under high pressure to ensure stable supply over a long period of time. Spherical tanks are the most suitable type of pressure vessel and are widely used.

As a safety measure, the spherical tank body is periodically or irregularly opened and non-destructive inspections are carried out from the inside, in order to prevent cracks from occurring during operation over time. Of course, during the inspection, we will remove the stored high-pressure gas and remove the gas remaining at the same pressure as atmospheric pressure inside the tank body. The tank body is filled with water, a so-called water-filling operation, to replace water and residual gas to purge the residual gas, and then a work scaffold is set inside the tank body and predetermined inspection work is carried out. .

Therefore, although the object of the work scaffolding in the prior art is the inspection of the internal wall surface of the tank body, that is, the two-dimensional inspection, a three-dimensional work scaffold is assembled and installed three-dimensionally inside the tank body. It was in a similar manner.

<Problem to be solved by the invention> Therefore, in order to carry the materials for the work scaffold from the outside of the tank body into the inside through the upper manhole, it is necessary to increase the number of materials needed to construct the three-dimensional work scaffold. Because of this, the workability of loading and unloading through the manhole is poor and it takes a long time, and the disadvantage is that the inspection work takes a long time, resulting in high costs. It was hot too.

Furthermore, since the work scaffold is assembled three-dimensionally within the tank body, there is little freedom in assembly work, and there is a drawback that there is a lack of freedom in reliable predetermined inspections.

<Object of the Invention> The object of the invention of this application is to solve the technical problems of work and inspection based on a three-dimensional work scaffold for two-dimensional inspection of the inner surface of the tank body of a spherical tank based on the above-mentioned prior art. The goal is to realize efficient inspection work at the one-dimensional intersection of the ring-shaped circumference of the tank body.
The present invention also provides an excellent spherical tank inspection method that utilizes water filling work required for residual gas purging to shorten the inspection work period and improve work efficiency, thereby benefiting the field of storage technology application in the energy industry, and the method. The purpose is to provide an inspection device that can be used directly.

<Means/effects for solving the problem> In order to solve the above-mentioned problem, the structure of the invention of this application, which is based on the scope of the above-mentioned patent claims, is to solve the above-mentioned problem. After draining the stored fluid inside and filling the inside with water to purge the remaining gas, the level of water filled up to the upper manhole level should be reduced to a level sufficient for initial work, i.e. 1.5 to 1.6 meters. After lowering the water level to a certain extent, the materials for the floating scaffold were brought in through the upper manhole, and the collapsible floating structure of these materials was integrated with the platform type scaffold body and assembled into the floating unit.
Next, a predetermined number of floating units are connected to each other using bellows-type connectors, etc., and a foldable guard is installed so that it faces the ring-shaped part where the water at the relevant level intersects with the tank body. They are connected to form a floating scaffold, and predetermined maintenance and inspection work such as non-destructive inspection of the inside of the tank body from the scaffold body of the floating scaffold is carried out, and during this period water is continuously or intermittently drained. Lower the water level, increase the number of floating units using floating scaffolding materials brought in from the upper manhole, and extend the circumference of the floating scaffolding by connecting the floating units with connecting bodies to expand the floating scaffolding so that the water level drops below half the level. From the point where the floating scaffold is broken, the floating scaffold is sequentially dismantled, the dismantled floating structure and the materials of the dismantled floating structure are released on the water surface, or they are allowed to sink, and the circumference of the floating scaffold is gradually reduced to create a floating scaffold. After all the water has been drained, all the floating scaffolding is dismantled and carried outside through the lower manhole, and the water draining process is used as it is to bring it back to the water surface. Technical measures have been taken to ensure that work such as inspection of the tank body at the ring-shaped intersection with the inner surface of the tank body can be carried out reliably.

<Embodiments> Next, embodiments of the invention of this application will be described below with reference to the drawings.

First, the method for inspecting a spherical tank, which constitutes one of the gist of the invention of this application, will be explained in sequence according to FIGS. 7 to 13. As shown in FIG. A spherical tank body 4 of the tank 3 is supported, and when performing an open inspection on the tank body 4, the gas stored at high pressure is removed and the residual gas, which is brought to the same pressure as the atmosphere, is Similarly to the embodiment, by injecting water 5 and increasing its level, residual gas purge is performed and water and residual gas are replaced.

When the residual gas purge is completed, the highest level of the water 5 has reached the upper manhole 6, but once the water reaches a level that can be used for normal inspection work, that is, about 1.5 to 1.6 meters from the manhole 6, the water 5 reaches the upper manhole 6. The level of water 5 is lowered as shown in FIG. The tank body 4 is floated close to the intersection of the water 5, and the upper inner surface of the tank body 4 between the upper manhole 6 and the water level of the water 5 is subjected to non-destructive inspection and painting work. In the process of lowering the surface level, the floating scaffold 7 is assembled by carrying in floating scaffold materials from the upper manhole 6 to increase its circumference, and the scaffold 7 is subjected to a predetermined inspection. As shown in the figure, the above process is repeated until the water surface level of the water 5 reaches the level of the diameter of the tank body 4 of the spherical tank 3, and the test is performed.

As shown in FIGS. 9 and 10, when the water is drained, the water surface level of the water 5 decreases, but at that time, the circumference of the floating scaffold 7, which has the maximum length, decreases.
The units of the floating scaffold 7 may be dismantled one by one and floated to the center of the water surface, or they may be allowed to settle and accumulate in the lower manhole 8 at the lower end of the tank body 4. As shown in Figure 11, the floating scaffold 7 is dismantled to shorten the circumference while gradually lowering the water surface level, predetermined inspection work on the inner surface of the tank body 4 is continued, and finally the water level is lowered.
After the materials have been discharged, as shown in FIG. 12, the materials of the floating scaffold 7 are accumulated around the lower manhole 9 at the bottom of the tank body 4, and each dismantled material is removed from the lower manhole 9. It is taken out to the outside, and the residual gas purge and inspection work is completed as shown in FIG. 13.

Therefore, to explain the floating scaffold 7 used in the above inspection method and its assembly and disassembly process,
In the embodiment shown in the figure, reference numeral 10 denotes a bag-type floating body that is connected in three rows in the width direction, and its diameter is the same as that of the upper and lower manholes 6 and 9 of the tank body 4.
It has a size that allows it to be inserted smoothly in the longitudinal direction, and the length is around 2 to 3 meters and is formed to be easy to assemble. Air is injected from the check valve of each floating body 10 through an air hose (not shown) to inflate it to form a raft-shaped floating body unit, and then a rectangular platform type formed in a predetermined manner from aluminum material is formed. Scaffolding bodies 11, 11... are carried in through the upper manhole 6, placed on the floating body 10 in a predetermined position, and assembled to the units of the floating body 10 via the hooks 12, 12....

In this way, each unit of the floating body 10 of the floating body scaffold 7 formed is connected to a bellows-type connecting body 14 made of soft PVC or cloth-lined rubber via the hook 15, and each unit is connected to each other. are connected in a raft shape and floated in a polygonal shape as much as possible along the ring-shaped boundary where the water surface of the water 5 and the tank body 4 intersect, as shown in FIGS.

Then, aluminum frame-shaped guards 13, 13, .

Depending on the design, as shown in Figures 1 and 4, in order to maintain the horizontal posture of the floating bodies 10, 10...
It is also possible to assemble the units of each floating body 10 of the floating body scaffold 7 via frames 16 made of aluminum or the like.

As mentioned above, each unit of the floating scaffolding 7 is connected to the upper manhole 6 in the process in which the water surface of the water 5 descends to the maximum diameter part (equator part) of the tank body 4, as shown in FIGS. 8 and 9. Materials such as the floating body 10, the scaffolding body 11, the guard 13, the connecting body 14, etc. are carried in from there, and the number of connections in the circumferential direction of the floating scaffolding 7 is increased to create a ring-shaped boundary between the water surface of the water 5 and the tank body 4. As the circumference of the floating scaffold 7 increases, the circumference of the floating scaffold 7 is increased and predetermined inspection work such as non-destructive inspection is carried out on the scaffold bodies 11, 11..., but in reality, as the water surface falls, the floating scaffold 7 increases in circumference. The circumferential length of the scaffold 7 is increased, and it is possible to conduct a thorough inspection by networking in one dimension in the circumferential direction of the floating scaffold 7 with respect to the two-dimensional plane of the inner wall surface of the tank body 4.

As shown in FIGS. 9 and 10, when the water surface of the water 5 falls below the maximum diameter part of the tank body 4, the circumferential length of the floating scaffold 7 naturally decreases; In this case, the connecting bodies 14 connected via the hooks 15 are removed, one floating scaffold 7 is dissociated one by one, and the floating scaffolds 7 are left floating on the water surface inside (closer to the center).
The work scaffolding 11 and the guard 13 may be dismantled and submerged below the water surface and lowered to the lower part of the tank body 4, and as the water surface descends, this process is repeated to sequentially contract the floating scaffolding 7, and finally the above-mentioned As shown in FIG. 12, after the water 5 is discharged,
The floating body 10, scaffold body 11, guard 13, etc. of each floating scaffold 7 can be dismantled and carried out from the lower manhole 9.

In addition, in the embodiment shown in FIGS. 5 and 6, a floating body 10' corresponding to the floating body 10 of the above-mentioned embodiment is the same as the floating body 1.
0' is filled with urethane, foamed polystyrene, etc. in an aluminum type shell with a diameter length that is approximately the same size as 0'. The rectangular scaffold bodies 11', 11'... are connected to each other via hooks, and a guard 1 is attached to one side of them in the same manner as in the above embodiment.
3 and 13 are planted to form a unit of floating scaffold 7', and the floating scaffolds 7' and 7' are connected to each other via a hook by a bellows type flexible PVC connecting body 14 as in the above embodiment. In this embodiment, as the water level of the water 5 falls, the floating scaffold 7'
The expansion/contraction process for increasing/decreasing the number of connections is substantially the same as in the above embodiment.

In order to avoid the floating scaffolds 7, 7' from swinging in the horizontal direction during the inspection work, as shown in FIG. You can deal with this by doing this.

It goes without saying that the embodiments of the invention of this application are not limited to the above-mentioned embodiments; for example,
Various methods can be used, such as placing a sheet made of soft PVC or the like on the water surface inside each floating scaffold to prevent jigs and other objects from sinking to the bottom of the tank body, or allowing open floating scaffolds to accumulate. The following aspects can be adopted.

<Effects of the Invention> As described above, according to the invention of this application, basically, in an open inspection of a spherical tank for gas storage, etc., the water surface and the tank body are measured by using the process of filling and discharging replacement water used for purging residual gas. An excellent effect is achieved in that the two-dimensional inner surface of the tank body can be thoroughly networked using the one-dimensional circumference of the intersection of the two-dimensional part and the inner surface of the tank body, allowing complete inspection.

Then, connecting bodies and guards are connected to the floating body brought in from the upper manhole of the tank body to form a polygonal floating scaffold along the ring-shaped boundary, and the scaffold body installed on the floating scaffold can be attached to a predetermined area. Therefore, the inner central space of the tank body is not used at all, and only the ring-shaped boundary between the water and the tank body can be used. There is no need to form a three-dimensional work scaffold, and there is no need to assemble the scaffold after the water has been completely drained, so the construction period can be shortened.
As a result, an excellent effect of reducing costs can be achieved.

In addition, compared to the conventional three-dimensional construction of work scaffolds, floating scaffolds have the advantage of being cheaper in terms of materials because they require significantly fewer materials.

In addition, the worker can inspect the inner surface of the tank body simply by moving on the scaffold body of the floating scaffold in the circumferential direction of the tank body inner surface, and the working conditions are good.
Therefore, excellent effects are achieved in that work efficiency is high and the work can be carried out efficiently and safely with little effort.

[Brief explanation of drawings]

The drawings are explanatory diagrams of an embodiment of the invention of this application, in which Fig. 1 is a schematic plan view of the floating scaffold, Fig. 2 is a side view of the same, and Fig. 3 is a plan view of the floating scaffold floating inside the tank body. Figure 4 is a partial cross-sectional side view, Figures 5 and 6.
The figure is a schematic side view and a plan view of another embodiment of the floating scaffold corresponding to FIGS. 1 and 2, and FIGS. 7 to 13 are schematic diagrams showing the process of inspecting the tank body using the floating scaffold. 3... Spherical tank, 4... Tank body, 7... Floating scaffold, 10... Floating body, 11... Scaffolding body, 14... Connecting body, 13... Guard, 6... Upper manhole, 9... Lower manhole.

Claims (1)

[Scope of Claims] 1. A method for inspecting a spherical tank, in which the tank body of the spherical tank is filled with water to purge residual gas, and then a work scaffold is installed inside the tank body to perform predetermined work on the tank body. After the residual gas is purged by filling with water, the water level is lowered to a predetermined level, and the assembly materials of the floating body forming the floating scaffold, which can be freely taken in and out from the upper and lower manholes, the connecting materials for the floating bodies, and the guard of the floating body are carried in from the upper manhole. Then, as the water level decreases, the floating scaffold is placed on the water surface along the circumferential boundary between the water surface and the tank body, and the above-mentioned materials are placed floating on the water surface in the shape of a raft. A method for inspecting a spherical tank characterized by continuing the prescribed inspection work by increasing the size of the structure, expanding the size of the structure, dismantling it, and reducing the size of the tank, and after discharging the water, the materials from which the floating scaffold has been dismantled are taken out from the lower manhole. 2. In a device for inspecting a spherical tank that is carried into and assembled inside the tank body of a spherical tank and performs prescribed inspection work on the inner surface of the tank body, a platform-type scaffolding body is equipped with a predetermined number of floating bodies that can be folded and reduced in size with buoyancy. The floating bodies are connected and assembled adjacent to each other through the water and the tank body, and are further connected by elastic connecting bodies along the circumferential boundary between the water and the tank body, and the floating body has a frame-shaped guard. A device for inspecting a spherical tank, characterized in that it is attached to form a floating scaffold.