JP2561220Y2 - Evaporative gas discharge nozzle structure of low temperature liquefied gas tank - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dispensing nozzle which is opened in a gas phase of a low-temperature liquefied gas tank and discharges evaporative gas.
In particular, the present invention relates to an evaporative gas discharge nozzle structure of a low-temperature liquefied gas tank that prevents suction of a stored liquid due to sloshing or the like.

[0002]

2. Description of the Related Art In recent years, low-temperature liquefied gas tanks for storing low-temperature liquefied gases such as LPG and LNG have been often buried underground.
Such an all-underground low-temperature liquefied gas tank can be easily buried by making the roof part low and flat instead of protruding in a dome shape, and at the same time can effectively use land on the ground.

In general, a low-temperature liquefied gas tank is composed of a tank having an open top and a bottomed cylindrical shape, and a roof covering the opening of the tank. A liquid phase low-temperature liquefied gas (hereinafter simply referred to as low-temperature liquefied gas or liquid storage) is stored in the tank body, and the space from the liquid surface to the roof is a gas-phase low-temperature liquefied gas (hereinafter referred to as evaporative gas). Filled to form the gas phase. In such a low-temperature liquefied gas tank, the maximum amount of the stored liquid is set according to the size, structure, and the like, and the liquid level at that time is referred to as the maximum liquid level.

On the roof of a low-temperature liquefied gas tank,
A discharge nozzle having an opening is provided in the gas phase portion in the tank so as to be inserted from the outside. The discharge nozzle is connected to an evaporative gas compressor or the like provided outside via a pipe. The discharge nozzle discharges the evaporative gas in the tank by the suction operation of the evaporative gas compressor. In this way, the discharge nozzle is for discharging only the evaporative gas, so that the opening thereof is positioned higher than the position of the highest liquid level so as not to be immersed in the liquid storage, and is therefore provided by being inserted through the roof. Have been.

[0005]

However, some low-temperature liquefied gas tanks have a low roof, like the above-mentioned all-underground low-temperature liquefied gas tank, and therefore have a small gap between the maximum liquid level and the roof. There is. Even in such a case, if the opening of the dispensing nozzle is positioned higher than the position of the highest liquid level, it goes without saying that there is usually no problem.

However, in a tank such as a low-temperature liquefied gas tank containing a liquid stored in a large tank, when the entire tank is vibrated due to an earthquake or the like, the stored liquid causes sloshing, and the liquid level is large. It is known to cause swell. Therefore, when the sloshing occurs when the storage amount is sufficiently large, the liquid level may instantaneously exceed the maximum liquid level and approach the roof.

As described above, when the liquid level in the tank rises due to sloshing or the like, in a tank in which the distance between the highest liquid level and the roof portion is small as described above, the opening of the discharge nozzle is immersed in the liquid storage. I can't help being done. If the opening of the discharge nozzle is immersed in the storage liquid in this way, the momentum of the sloshing and the suction force of the evaporative gas compressor combine to push the storage liquid into the discharge nozzle, and the storage liquid passes through the pipe. It may reach the evaporative gas compressor.

On the other hand, since the operation of the evaporative gas compressor is hindered when the liquid phase is sucked, it is preferable that the stored liquid reaches the evaporative gas compressor through the pipe due to sloshing or the like as described above. Absent. However, in the case of a tank having a small gap between the highest liquid level and the roof as described above, there is a problem that inflow of the stored liquid due to sloshing or the like is inevitable.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide an evaporative gas discharging nozzle structure of a low-temperature liquefied gas tank which prevents suction of a stored liquid due to sloshing or the like.

[0010]

In order to achieve the above-mentioned object, the present invention is directed to an opening of a dispensing nozzle, which rises to a liquid storage surface when a liquid level in a tank rises due to sloshing or the like. And a vent hole for releasing a negative pressure in the discharge nozzle closed by the float valve when the liquid storage surface is lowered from the opening in the discharge nozzle. .

[0011]

With the above arrangement, when the liquid level in the tank rises due to sloshing or the like, the float valve floats on the rising liquid storage surface and closes the opening. By closing the opening of the discharge nozzle, the stored liquid is prevented from entering the discharge nozzle.

In addition, even if the opening of the dispensing nozzle is closed as described above, since the gas vent hole for releasing the negative pressure in the dispensing nozzle is provided, the liquid level subsequently drops from the opening. At this time, the float valve can be lowered to open the opening without being sucked by the negative pressure in the discharge nozzle.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

A low-temperature liquefied gas tank 1 shown in FIG.
Is a tank body 2 formed of a side plate forming a body portion and a bottom plate forming a bottom portion, the upper portion being opened and formed into a bottomed cylindrical body.
And a roof 3 that covers the opening of the tank body. A low temperature liquefied gas such as LPG and LNG is stored in the tank body as a storage liquid W, and the space from the liquid surface S to the roof 3 is filled with the evaporative gas G to form a gas phase. In the figure, an arrow Smax indicates the maximum liquid level of the storage liquid W that can be stored in the low-temperature liquefied gas tank 1.

On the roof 3 of the low-temperature liquefied gas tank 1, there is provided a discharge nozzle 4 having an opening in the gaseous phase portion, which is inserted from the outside. The discharge nozzle 4 is connected via a pipe 5 to an evaporative gas compressor or the like provided outside. The discharge nozzle 4 discharges the evaporative gas G from the tank by the suction operation of the evaporative gas compressor.

As shown partially in FIG. 2 (a), the discharge nozzle 4 is formed in a tubular shape having a predetermined diameter, is suspended from the roof 3 and has a horizontally circular opening 4 at its lower end.
a is formed. The opening 4a has a maximum liquid level Smax.
It is located at a higher position. Pins 5 that are located above the opening 4a and that extend radially outward are provided on both sides of the outer peripheral portion of the dispensing nozzle 4. Dispensing nozzle 4
Below the opening 4a, a disc-shaped lid plate 6 facing and separated from the opening 4a and having a diameter larger than that of the opening 4a.
Is provided. On both sides of the peripheral portion of the cover plate 6, guides 7 extending upward and having a closed slit at the top are provided.
Is provided. The pins 5 are respectively inserted through the slits of the guides 7 on both sides, and the lid plate 6 is suspended and supported by the dispensing nozzle 4 by the engagement between the guides 7 and the pins 5. The length of the guide 7 is set between the pin 5 and the opening 4.
Therefore, when there is no external force, the lid plate 6 is located apart from the opening 4a. When an external force is applied from below, the lid plate 6 is guided by the guides 7 and the pins 5 and rises. , And is configured to contact the opening 4a. The cover plate 6 is made of a material that is lighter than the specific gravity of the liquid storage W or has a larger bottom area with respect to its own weight, and is configured to float as the liquid storage surface rises. That is, the float valve 8 is formed in which the cover plate 6 is a valve body and the opening 4a is a valve seat. The float valve 8 can float on the liquid storage surface S and close the opening 4a when the liquid storage surface S in the tank rises due to sloshing or the like.

On the other hand, as shown in FIG. 3 (a), on the side surface of the dispensing nozzle 4 which is inserted into the roof portion 3 and droops into the low-temperature liquefied gas tank 1, the inside and outside of the dispensing nozzle 4 are brought close to the roof portion 3. Is provided with a gas vent hole 9 communicating with the gas outlet. The opening area of the gas vent hole 9 is formed smaller than the opening area of the opening 4a and is not sufficient for discharging the evaporative gas G. However, when the float valve 8 is closed, the discharge nozzle 4 When the pressure is more negative, the opening area is sufficient to release the negative pressure.

The discharge nozzle 4 is provided with a baffle plate 10 extending from the inner peripheral wall and covering the gas vent hole 9 from above to inside.

Next, the operation of the embodiment will be described.

In the low-temperature liquefied gas tank 1, the discharge nozzle 4 and the float valve 8 are located at a position sufficiently higher than the maximum liquid level Smax. Are open, the operation such as the discharge of the evaporative gas G can be achieved without any trouble.

When the liquid storage surface S is substantially at the maximum liquid level Smax and a large swell as shown by Ss in the figure occurs due to sloshing or the like, when the rising liquid surface reaches the cover plate 6 of the float valve 8. , Buoyancy or the pressing force of the reservoir
Rises up and is guided by the guide 7 and the pin 5.
When the upper surface of the cover plate 6 is pressed against the opening 4a as shown by 6s in FIG. 1, the float valve 8 is closed. Since the float valve 8 is closed, when the liquid level still rises thereafter, the liquid does not enter the discharge nozzle 4 despite the discharge nozzle 4 being immersed in the liquid storage. . Thereafter, when the liquid level drops, the lid plate 6 drops by its own weight or the suction force of the stored liquid, and the float valve 8 is opened. At this time, since the opening 4a is in the gas phase, the liquid does not enter.

Further, during the discharging operation of the evaporative gas compressor, the float valve 8 is closed, the pressure in the discharging nozzle becomes more negative than the gas pressure in the gas phase, and thereafter, the liquid storage surface S drops from the opening 4a. When the gas vent hole 9 is in the discharging nozzle 4
Since the negative pressure inside is released, the float valve 8 is not adsorbed by the negative pressure. That is, the opening of the float valve 8 is smoothly achieved.

Further, when the liquid storage surface rises sharply due to sloshing or the like and reaches the gas vent hole 9, the liquid may enter the discharge nozzle 4 from the gas vent hole 9. However, the opening area of the gas vent hole 9 is formed to be smaller than the opening area of the discharge nozzle 4, so that the amount of the inflow liquid storage is limited, and the slightly inflowing liquid flows through the gas vent hole 9 from above. When it hits the baffle 10 covering the inside, its momentum is changed downward. As a result, the inflowing liquid flows down onto the float valve 8 and further flows down with the opening of the float valve 8.

As described above, according to the evaporative gas discharge nozzle structure of the low-temperature liquefied gas tank of the present invention, suction of the stored liquid by sloshing or the like is prevented, and the stored liquid reaches the evaporative gas compressor through the piping. Disappears.

Next, another embodiment of the present invention will be described.

FIG. 2B shows an example in which the float valve 8 has another configuration. At the lower end of the dispensing nozzle 4, a plurality of support bones 11 a extending radially outward are provided with openings 4.
is supported, a plurality of vertical bones 11c are extended downward from the outer bone 11b at intervals along the circumferential direction, and the lower end of each vertical bone 11c has a circumferential and radial inner end. A plurality of bottom bones 11d extending toward each other are provided so as to communicate with each other or with the bottom bones 11d. An opening 4a is provided inside the skeletal structure 11 formed by these bones.
A disk-shaped lid plate 6 having a larger diameter than that is housed in a vertically movable manner. The lid plate 6 is used for the bottom bone 11d when the liquid storage surface is low.
When the liquid storage surface is placed on the liquid storage surface and rises due to sloshing or the like, it can float on the liquid storage surface and close the opening 4a.

An elastic material is interposed between the valve seat side, that is, the dispensing nozzle 4 or a structure fixed to the dispensing nozzle 4, and the valve body, that is, the cover plate 6, to facilitate opening of the float valve 8. You can also. For example, as shown in FIG. 2A, the float valve 8 is configured by interposing a spring material 12 or the like between the pin 5 and the cover plate 6, and the spring material 12 is attached when the float valve 8 is closed. To maintain the repulsive force for opening the float valve 8. This repulsive force is added to the gravity of the cover plate 6 and the dispensing nozzle 4
The float valve 8 is opened even if the pressure inside is negative.

Next, as another embodiment of the gas vent hole 9,
As shown in FIG. 3B, a gas discharge nozzle 13 having a smaller diameter than the discharge nozzle 4 can be inserted into the discharge nozzle 4, and the gas discharge nozzle 13 can be attached with an inclination. The opening of the degassing nozzle 13 has a degassing hole 9.
Is formed, and the liquid flowing in from this flows down in the discharge nozzle 4 due to its inclination. Therefore, this example
An effect equivalent to that of the previous embodiment shown in FIG.

[0029]

[Effects of the Invention] The present invention exhibits the following excellent effects.

(1) Since the suction of the stored liquid at the time of sloshing is prevented, no trouble occurs in the operation of the evaporative gas compressor.

(2) Since the suction of the stored liquid at the time of sloshing is prevented, the maximum liquid level can be provided close to the roof, and the volume efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a low-temperature liquefied gas tank according to an embodiment of the present invention.

FIG. 2 is a detailed perspective view of a float valve showing one embodiment and another embodiment of the present invention.

FIG. 3 is a detailed sectional view of a gas vent hole showing one embodiment of the present invention and another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Low temperature liquefied gas tank 4 Discharge nozzle 4a Opening 8 Float valve 9 Gas vent hole

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hidenori Suzuki 3-2-1-16 Toyosu, Koto-ku, Tokyo Ishikawa Shima Harima Heavy Industries, Ltd.

Claims (1)

(57) [Scope of request for utility model registration] 1. A dispensing nozzle having a low-temperature liquefied gas, which is inserted through a roof of a tank for storing a low-temperature liquefied gas, has an opening in a gas phase portion in the tank, and discharges evaporative gas therefrom. At the opening of the nozzle, a float valve that floats on the liquid storage surface and closes the opening when the liquid storage surface in the tank rises due to sloshing or the like is provided. An evaporative gas discharge nozzle structure for a low-temperature liquefied gas tank, wherein a gas vent hole is formed for releasing a negative pressure in the discharge nozzle closed by the float valve when the float valve further descends.