JPS6044559B2 - Tank liquid receiving pipe discharge end structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure in which a liquid receiving pipe suspended inside a tank for storing natural liquefied gas, etc. has a branched discharge end, and in particular, This invention relates to a liquid receiving pipe discharge end structure of a tank in which the branch discharge ends do not touch the inner wall surface of the tank, but the discharge directions intersect with each other within the inner wall surface area to eliminate dynamic pressure.

As is well known, various types of storage tanks have been developed and improved, and a large number of them have been put into operation.

In recent years, tank capacity has become larger from the perspective of mass stockpiling, and from the standpoint of safety, underground and semi-underground types are increasingly being adopted. Therefore, as a natural design, the head pressure of the receiving pipe tends to gradually increase.

By the way, the structure of the liquid receiving pipe into the tank that has been generally devised in the past is as shown in FIG. A circulation cylinder 5 is disposed at the lower end 4', and the circulation cylinder 5
The receiving liquid 6 was being discharged from the upper and lower ends.

Further, in the embodiment shown in FIG. 2, the lower end 4' of the receiving pipe 4 is opened directly facing the tank bottom wall 2', so that the liquid 6 is discharged.
Alternatively, as shown in FIG. 3, the roof 3 may be
It branches into multiple receiving pipes at the top, each end 4', 4'...
・It was common to form the mixture into a stirred shape.

However, since most of the conventional receiving pipe discharge ends 4' of this kind include a portion that directly faces the inner wall surface of the bottom wall 2' and side wall 2'' of the tank 2, the following problems occur. There was a problem.

Firstly, as mentioned above, due to the increasing size of the tank 2 and the competing conditions with the underground type, the head of the receiving pipe 4 is large and the dynamic pressure is high. There is a drawback that the influence over time is undesirable, and in recent membrane type tanks, the blowout energy applied to the internal membrane is not only applied to the inner wall surface.
This has led to the emergence of defects that have an adverse effect on the safety of nearby structures.

The purpose of the present invention is to solve the problem of the discharge end of the hanging receiving pipe into the tank based on the above-mentioned prior art, and the liquid jetted from the discharge end collides in an area as close as possible without reaching the inner wall surface of the tank. It is an object of the present invention to provide an excellent tank liquid receiving pipe discharge end structure which eliminates the energy of the ejector and prevents any adverse safety effects on the inner wall surface of the tank and nearby structures.

The structure of the present invention in accordance with the above object is such that the stored liquid fed into the tank by the receiving pipe is branched into multiple lines from the discharge end and spouted out, thereby preventing the liquid from reaching the inner wall of the tank. The gist of this is that each branched jet liquid stream collides with each other to eliminate the jetting energy, thereby preventing the adverse effects of dynamic pressure on the tank inner wall surface and nearby structures.

Next, an embodiment of the present invention will be described below based on the drawings from FIG. 4 onwards.

Note that the same parts as those in the embodiments of FIGS. 1, 2, and 3 will be described using the same reference numerals. A semi-underground tank 2 constructed on the ground 1 is for storing natural liquefied gas such as LNG, and a receiving pipe 4 extends downward from the dome roof tank 3 of the tank 2, and its lower discharge end The portion 4'' is branched at a portion that does not reach the lower end 2'' of the tank, and is formed in a U-shape so as to face each other, and the spouting ends 4'', 4'' may be on the same straight line, Also, make sure that the jetting directions intersect,
Furthermore, the intersection points are located within the tank inner wall surfaces 2'', 2''.

Therefore, when operating the tank 2, especially when receiving liquefied natural gas 6 from the receiving pipe 4 after the tank is constructed, the lower jetting ends 4'', 4'' are configured to cross oppositely, so that The ejector energy due to the dynamic pressure associated with ejection is canceled out by the consumption of collision energy and does not reach the inner wall surfaces 2'', 2''. Therefore, it is stored without adversely affecting the membrane etc.

Of course, in the illustrated embodiment, the ejection ends 4'', 4'' are not limited to one pair, but may be two or three pairs, and do not need to be on the same straight line.

In addition, in the embodiment shown in FIG.
``'' do not face each other on the same straight line, but are bent upward and the jets are directed so as to form intersection points that do not intersect in the hanging parts leading to the jetting ends 4'''', 4''''. It is formed so that the energy of the blowing machine does not have an adverse effect on the tank inner wall surfaces 2'', 2''.

It goes without saying that the number of branched jet ends is not limited to two in this embodiment, and the embodiments of the present invention are not limited to the two embodiments described above.

Further, the tank to which the present invention is applied is not only a membrane type double shell low temperature tank, but also a tank provided with a liquid receiving pipe of the same purpose. According to the invention as described above,
In the liquid receiving pipe hanging down into the tank, the hanging discharge end of the receiving pipe is provided with a plurality of branches, so that the plurality of branched discharge ends do not face the tank inner wall surface and Basically, when the stored liquid is received in the tank, the energy due to the dynamic pressure of the received liquid is applied to the inner wall of the tank, especially in the direction of intersecting each other at one point. There is little adverse effect on the inner wall surface of the inner tank, such as the membrane, and therefore, there is an excellent effect of eliminating the possibility that weak spots will develop on the inner wall surface of the tank over time or that unexpected stress will be applied to nearby structures.

In addition, as in recent years, when the tank capacity is large and underground type is used, and the head of the receiving pipe becomes large, the impact energy of the liquid jet dynamic pressure at the time of receiving is also large. The huge underground tank has a great advantage because it allows you to plan for the disappearance and absorption of the energy.
Furthermore, considering the difficulty of maintenance in underground tanks, the removal of adverse effects on the inner wall of the tank is an extremely significant advantage.

Furthermore, since the structure is simply to branch the hanging discharge ends so that the ejection directions intersect in a predetermined manner, it is easy to manufacture, the cost is low, and maintenance is not required.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are explanatory diagrams of the structure of the receiving pipe discharge end into a tank based on the prior art, Figure 4 and the following are explanatory diagrams of embodiments of the present invention, and Figure 4 is an overall outline of one embodiment. FIG. 5 is a partially enlarged explanatory diagram, and FIG. 6 is an explanatory diagram of another embodiment corresponding to FIG. 5. 2...Tank, 4...Reception pipe, 4''
,4″...discharge end.

Claims (1)

[Claims] 1. In a structure in which the end of a liquid receiving pipe suspended in a tank is branched into a plurality of branches, the end of the liquid receiving pipe is branched into a plurality of branches, does not directly face the inner wall surface of the tank, and A liquid receiving pipe discharge end structure for a tank, characterized in that the discharge directions of the branch discharge ends are formed so as to intersect with each other at one point within an inner wall surface of the tank.