JPH0516157Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an explosion structure for a tank that stores crude oil or other flammable liquid.

[Conventional technology]

A tank for storing flammable liquids such as crude oil and LPG has a cone-shaped or dome-shaped roof with the center part protruding upward at the upper end of the peripheral wall 1 installed on the ground, as shown in the schematic cross section in Figure 4. A plate 2 is stretched and configured to store a flammable liquid O such as crude oil inside.

In tanks that store this type of flammable liquid, if the internal pressure suddenly increases due to the effects of radiant heat from a fire near the tank and the entire tank is destroyed, the stored flammable liquid will leak into the vicinity. This will burn up and cause major secondary disasters. Therefore, in the event of an explosion, a structure is required in which only the roof plate 2 is torn off and the explosion is released upwards.

On the other hand, strong wind currents flowing above the tank generate a large negative pressure on the top surface of the tank roof plate 2, but the roof plate 2 has the necessary strength so that it will not be torn off by this negative pressure. installation is required.

Conventionally, as an attachment means that satisfies the above requirements, as shown in an enlarged cross section of FIG. By fixing the ends of the welds around the entire circumference in an airtight state with fillet welds 4, and by making the leg length l of these welds 4 smaller than the thickness of the roof plate 2, the welds 4 can The tank was designed to break first and explode upwards, so that the entire tank would not be destroyed.

[Problem that the invention attempts to solve]

However, in the above-mentioned structure in which the roof plate 2 is attached by welding 4, it is desirable to make the leg length l of the weld 4 as small as possible in order to make the roof plate 2 easily peel off in the event of an explosion. From this point of view, there is a contradictory requirement that it is desirable to have a sufficient leg length l of the four welded parts, and the leg length l of the four welded parts is
Welding work to shorten the roof plate and ensure airtightness requires highly skilled techniques, making it difficult to attach the roof plate 2.

This invention drastically improves the problems of the conventional technology described above, and uses a bolt-based attachment structure instead of welding the roof panels, making the installation process easier while ensuring that the roof panels will not peel off in the event of an explosion. The purpose of this design was to provide a detonation structure for tanks.

[Means for solving problems]

In order to solve the problems of the above conventional technology,
This idea consists of a peripheral wall part established on a foundation, a roof plate placed over this peripheral wall part, a flange part formed horizontally at the upper end of the peripheral wall part, and bolts formed on this flange part. a hole, a bolt hole formed in a notch shape at a position corresponding to the bolt hole of the flange in the peripheral edge of the roof plate so as to open to an outer peripheral end of the peripheral edge, the flange and the roof plate; A bolt that is passed between the two bolt holes with a gasket interposed between the bolt and the peripheral edge of the bolt, and fixes the roof sheet to the peripheral wall by tightening the flange portion and the peripheral edge of the roof sheet. - When the pressure in the tank interior space surrounded by the peripheral wall and the roof plate increases and a tensile force is generated that pulls the peripheral edge of the roof plate toward its center, the peripheral wall Before being destroyed, the roof plate peripheral wall moves toward its center to overcome the frictional force caused by the tightening of the bolts and nuts, and the bolts and nuts are pulled out along the notches of the notched bolt holes. The fastening state of the bolt/nut is set so that the fastening state is released.

[Effect]

In the event that the pressure inside the tank suddenly increases and an explosion occurs, the bolts will be pulled out along the notch-shaped bolt holes in the roof plate because the roof plate will bulge upward and its diameter will shrink. As a result, part or all of the peripheral edge of the roof plate separates from the upper end of the surrounding wall, and the blast wave is released upward from this area, preventing the entire tank from being destroyed, and the blast wave is directed horizontally. In addition, the outflow of flammable liquid due to destruction of the peripheral wall is prevented, and the occurrence of secondary disasters is prevented.

〔Example〕

Embodiments of this invention will be described below with reference to FIGS. 1 to 3, with the same reference numerals assigned to the same members as those in FIG. 5.

FIG. 1 shows an enlarged cross-section of the joint between the peripheral wall 1 and the roof plate 2 of a tank according to this invention, and FIG. 2 shows a plan view of the same.

In the above embodiment, the horizontal flange portion 3a of the top angle 3 fixed to the upper end of the peripheral wall portion 1 by welding or the like projects outward from the tank.
Bolt holes 5 and 6 are formed correspondingly at a certain interval in the circumferential direction in the peripheral edge 2a of the roof sheet 2 which is overlapped with the flange 3a and the peripheral edge 2a of the roof sheet 2. The roof plate 2 is fixed to the peripheral wall 1 by screwing and tightening nuts 9 onto bolts 8 inserted into the bolt holes 5 and 6 with a gasket 7 interposed therebetween to maintain airtightness. .

Bolt holes 6 in the roof panel 2 in the illustrated embodiment
The bolts 8 have a slit structure that opens at the outer peripheral end of the peripheral edge 2a of the roof sheet 2, and when the roof sheet 2 bulges upward and deforms when subjected to internal pressure, the bolts 8
The peripheral edge 2a of the roof plate 2 can be easily removed from the roof plate 2. In the figure, 19 is a washer for preventing rainwater from entering.

Next, the action will be explained.

When the pressure inside the tank suddenly increases, leading to an explosion, the pressure inside the tank causes the pressure to concentrate on the inner surface of the central part of the roof plate 2 due to its medium-height shape, causing it to expand upward as shown by the chain line in Figure 4. The roof sheet 2 is deformed, and the peripheral edge 2a of the roof sheet 2 receives a large tensile force toward the center. At this time, the tensile force q of the roof plate 2 in the direction of the arrow in FIG. 1 is 16P×D/4, assuming tanθ=1/16.
(Here, P is the internal pressure and D is the internal diameter of the peripheral wall 1), so it is 16 times the upward force due to the internal pressure applied to the peripheral edge 2a of the roof shingle 2, and this force causes the peripheral edge 2a of the roof shingle 2 to move toward the center. This force causes the roof plate 2 to
The bolt hole 6 overcomes the frictional force caused by the tightening of the bolt 8 and comes off from the bolt 8, and is ejected upward from this detached part. Therefore, the peripheral wall portion 1 is not destroyed, and the occurrence of a secondary disaster in which the flammable liquid inside flows out into the vicinity and causes a fire is prevented.

[Effect of idea]

As explained above, this idea involves inserting bolts into bolt holes formed in the flange at the upper end of the surrounding wall and bolt holes formed in the shape of a notch in the peripheral edge of the roof plate, and tightening them with nuts. Since it is fixed, when the pressure inside the tank increases and the peripheral edge of the roof plate is pulled toward its center, the bolt can be pulled out along the notched bolt hole in the peripheral edge of the roof plate.
It is possible to release the fastened state between the surrounding wall surface and the roof plate. Therefore, even if the pressure inside the tank were to rise abnormally and cause an explosion, the peripheral edge of the roof plate would come off from the surrounding wall, and the blast would be emitted upwards from this detached part, causing the blast to flow horizontally. This prevents the explosion from causing damage to nearby facilities, etc., and since the surrounding wall is not destroyed, there is no leakage of flammable liquid inside the tank, which prevents secondary disasters due to leakage of flammable liquid. can do. Furthermore, since there is no need to weld the peripheral wall and the roof plate, no skill is required to install the roof plate, and the welding must be carried out in such a way that continuous airtightness can be maintained over the entire circumference. In addition, it was easy to tear and had to be done carefully to maintain the necessary strength, but with this invention, by appropriately selecting the bolt pitch and tightening force, it was possible to obtain the necessary mounting strength while creating a structure that was easy to remove. In terms of maintaining airtightness, complete airtightness can be easily achieved by simply interposing a gasket between the flange of the peripheral wall and the peripheral edge of the roof sheet. It has excellent effects.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of the main part showing an embodiment of this invention, Fig. 2 is a plan view thereof, Fig. 3 is a schematic longitudinal sectional view showing an example of a tank to which this invention is applied, and Fig. 4. is a partially enlarged cross-sectional view showing a conventional roof plate mounting structure. 1... Peripheral wall portion, 2... Roof plate, 2a... Peripheral edge of roof plate, 3... Top flange, 3a... Flange portion, 5, 6... Bolt hole, 7... Gasket, 8... Bolt .

Claims (1)

[Scope of Claim for Utility Model Registration] A peripheral wall established on a foundation, a roof plate placed over the peripheral wall, a flange formed horizontally at the upper end of the peripheral wall, and a flange formed on the flange. a bolt hole formed in the peripheral edge of the roof plate; a bolt hole formed in a notch shape at a position corresponding to the bolt hole of the flange part in the peripheral edge of the roof plate so as to open to the outer peripheral end of the peripheral edge; and the flange part. and the circumferential edge of the roof plate, with a gasket interposed between the two bolt holes, and by tightening the flange and the circumferential edge of the roof plate, the first roof plate is attached to the circumferential wall. bolts and nuts for fixing the tank, and when the pressure in the tank interior space surrounded by the peripheral wall and the roof sheet increases and a force is generated that pulls the peripheral edge of the roof sheet toward its center, Before the peripheral wall part is destroyed, the roof plate peripheral wall part moves toward its center to overcome the frictional force caused by the fastening of the bolts and nuts, and the bolts and nuts fit into the notches of the notched bolt holes. 1. A tank detonation structure, characterized in that the tightened state of the bolt and nut is set so that the tightened state can be removed by pulling the bolt and nut along the side.