JPS60151193A - Strength testing method of lng spherical tank - Google Patents

Abstract

PURPOSE:To perform the strength test of a tank in parallel with the construction of a hull by incorporating LNG spherical tanks in the hull under construction in a dock and offsetting the weight of the fresh water fed into the tank with the buoyancy due to the sea water guided into the dock. CONSTITUTION:Multiple LNG spherical tanks 1 are incorporated in a hull 8 under construction in a dock 7. The weight of the fresh water 4 fed in a tank 1 is offset by the buoyancy of the hull 8 floated by the sea water 9 guided into the dock 7, and the strength test of the LNG spherical tank 1 is performed. Due to this offsetting, the ground subsidence of the dock 7 bottom is prevented, the safety factor of the weight loaded on blocks 10 is secured, and fresh water 4 can be fed to test the strength of the LNG spherical tank 1 subject to feed water limitation in parallel with the construction of the hull requiring a long time in the dock 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for testing the strength of LNG spherical tanks loaded onto LNG carriers.

[Prior art]

After construction of the LNG spherical tank to be loaded onto this type of LNG carrier, it is necessary to fill the LNG spherical tank 1 with fresh water and to conduct a strength test by applying a predetermined pressure.

To carry out this strength test, the conventional method 1 shown in Fig.
As shown in the figure, an LNG spherical tank 1 manufactured in advance at a factory on land is tested at a test I to facility 3 installed on land 2, and then loaded onto a ship.

However, in this conventional method I, the LNG required for the strength test
Four layers of fresh water supplied into the spherical tank 1 is 13o per unit.
oo TON, there is a problem in that it is very difficult to construct the test facility 3 in order to obtain the ground strength to prevent the ground containing the test facility 3 from sinking, in terms of space and construction.

In order to solve this problem, as in the conventional method 2 shown in FIG. Is there a way to solve the problem of ground subsidence by using the top of the hull 5 to perform the strength test of the L and NG spherical tanks 1? Since the amount of water used for - is limited by water supply restrictions, - group L N G spherical tank 1
For example, as shown in Figure 2, it takes about two weeks to supply water to the interior of the tank, and for example, as shown in Figure 2, it takes about two weeks to complete the test, including the strength test of the five LNG spherical tanks 1 and the cleaning and drying of the tank interior after the test. Since it takes three months, there was a problem in that the period for applying the stickers to the ship's hull after launch and before delivery was extremely long.

[Purpose of the invention]

The present invention has been devised to solve these problems in view of the above-mentioned conventional situation, and is designed to conduct a strength test of an LNG spherical tank using a half-built hull in a ditch. 1. The purpose of the present invention is to provide a strength test method for LNG spherical tanks that can complete the strength test of NG spherical tanks before launching.

[Structure of the invention]

The strength test method of the LNG spherical tank of the present invention which achieves the above object is to load a plurality of LNG rik type tanks onto a ship being constructed in a conduit, and to carry out water supply into the LNG spherical tank. This test is characterized by performing a strength test of an LNG spherical tank by offsetting the ff1ffi of fresh water by the buoyancy of a ship under construction that is floated by seawater introduced into a conduit.

〔Example〕

FIGS. 3 and 4 show an embodiment of the present invention. In the present invention, as shown in FIGS. Hull 8 currently under construction
These multiple I, N G spherical tanks 1
The strength test I of the LNG spherical tank 1 is now conducted by canceling out the weight of the fresh water 4 supplied into the tank by the buoyancy of the hull 8 under construction, which is floated by the seawater 9 introduced into the conduit 7. There is.

In other words, the buoyancy of the hull 8 under construction can be adjusted by adjusting the water depth I of ljσ water 9 introduced into the ditch 7 and the ballast I and water 12 supplied to the ballast I and tank 11 of the hull 8.
L added to the board 10 that supports the hull 8 that is currently under construction.
The weight of the fresh water 4 in the NG spherical tank 1 is offset by 1 Tiffl, and by offsetting the weight of the fresh water, -C, the ground subsidence at the bottom of the ditch 7 is prevented, and the weight 1 loaded on the board 10 is
In addition to ensuring the safety factor of ik, fresh water 4 for the strength test of LNG spherical tank 1, which has limited water supply, is supplied to conduit 7.
(conducted in parallel with the construction of hull 8, which requires a long period of time)
be able to.

For this reason, multiple LNG spherical tanks 1 were installed before launching the hull 1.
The strength test can be completed.

In addition, in carrying out the strength test, due to water supply restrictions, fresh water 4 cannot be supplied at the time of multiple LNG spherical tanks 1, but the hull 8 that houses this type of LNG spherical tanks 1 must be equipped with water for each LNG tank. Since each G spherical tank 1 is provided with an independent ballast tank 11, water 12 is injected into the ballast tank 11 at a position corresponding to the LNG spherical tank 1 at the position where fresh water 4 is supplied. By doing so, the buoyancy of the hull 8 during construction due to the seawater 9 in the conduit 7 is offset only by the weight of the fresh water 4 in the LNG spherical tank 1, and the balance between the front and back and left and right sides of the hull 8 is ensured. Make it.

The strength test of the LNG spherical tank 1 loaded into the hull 8 was as follows:
Bow and stern bulkheads 13 and 14 of hull 8
Since the construction can be started from the middle of construction when the hull 8 has been constructed and the entire hull 8 has become box-shaped, strength tests of multiple T, N, and G spherical tanks 1 can be performed before the bow and stern are connected to the hull 8 and constructed. By making it terminate,
It becomes possible to proceed with the construction of the hull 8 and the strength test of the LNG spherical tank l in parallel.

Therefore, by the time the hull 8 is launched, the LNG spherical tank 10) strength test, which requires a long period of time due to water supply restrictions, can be completed, thereby shortening the period for attaching the hull after launch and before delivery. can do.

〔Effect of the invention〕

In summary, the strength testing method for LNG spherical tanks according to the present invention involves loading a plurality of LNG spherical tanks onto a ship being constructed in a ditch, and
The weight of fresh water supplied into the Jξ-shaped tank is offset by the buoyancy of the hull under construction, which floats due to the seawater introduced into the ditch, and the strength test of the NG spherical tank is carried out. The buoyancy of the buoyant force offsets the weight of the fresh water in the NG spherical tank, which is added to the board that supports the hull of the ship in the middle of construction in the culvert. In addition to ensuring a safety factor for the weight loaded on the board, it is possible to supply fresh water for strength testing of LNG spherical tanks, which have limited water supply, in parallel with the long-term construction of the ship's hull in the conduit. .

Therefore, it is possible to complete the strength test 1 of the LNG spherical tank before launching the ship, so that the period for installing the ship after launching and before delivery can be shortened.

[Brief explanation of drawings]

Figures 1 to 2 show conventional examples.
The figure shows a side view of a conventional strength test conducted on an LJ at sea, Figures 3 to 1 show an embodiment of the present invention, and Figure 3 shows a strength test in a ditch. FIG. 4 is a perspective view of FIG. 3. 1...LNG spherical tank, 4...Water, 7...Drainage, 8...Hull, 9...Seawater.

Claims (1)

[Claims] Multiple LNG spherical tanks are loaded onto the hull of a ship under construction in a culvert, and the weight of fresh water supplied into the LNG spherical tanks is used to float the hull under construction using seawater introduced into the culvert. A strength test method for LNG spherical tanks that tests the strength of LNG spherical tanks by offsetting buoyancy.