JP5356888B2 - Tank for liquefied gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To display a liquid level accurately and stably, by reducing the fluctuation in the liquid level display caused by generation of bubbles in a connecting tube, when using a differential pressure type level gauge for a tank for liquified gas. <P>SOLUTION: The differential pressure type level gage 10 is connected to the tank 1 for liquified gas through each connecting tube 11, 13 on the low-pressure side and on the high-pressure side. A tip part 14, including an opening end 14a of a high-pressure side connecting tube 13, is inserted horizontally to the inside of a periphery of a bottom part of the tank 1. It is particularly preferable, that a plurality of small holes 14b, penetrating a wall surface of the connecting tube 13, be provided on an upper half part of the tip part 14 of the connecting tube 13. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The invention according to the claims relates to a liquefied gas tank into which liquid nitrogen, liquid hydrogen, or the like is placed, to which a differential pressure type level gauge is connected via a pressure guiding tube.

  In a liquefied gas tank containing liquid nitrogen, liquid hydrogen, or the like, a differential pressure type liquid level gauge is frequently used as a means for knowing the amount of liquefied gas inside. FIG. 10 shows a general usage mode of the differential pressure type level gauge 60 in the liquefied gas tank 6. As shown in the figure, the tank 6 has an inner tank 6a and an outer tank 6b, and a vacuum layer 6c as a heat insulating layer is provided between both tanks. The differential pressure type liquid level gauge 60 is attached to the outside of the tank 6, and the low pressure side and high pressure side pressure guiding pipes 61 and 63 with respect to the upper gas phase and the lower liquid phase bottom of the inner tank 6 a of the tank 6, respectively. Connected at. The difference in pressure between the pressure guiding pipes 61 and 63 is detected by the liquid level gauge 60 and displayed as the liquid level height. The use of such a differential pressure level gauge in a liquefied gas tank is described in, for example, Patent Documents 1 and 2 below.

  In the conventional differential pressure type liquid level gauge, including the examples of Patent Documents 1 and 2, the high pressure side pressure guiding pipe that connects the differential pressure detecting unit and the liquid phase bottom is shown in FIG. 11 or FIG. ) Is attached. That is, as shown in FIG. 11, a vertical portion 64d is provided at the distal end portion 64 of the high-pressure side pressure guiding tube 63, and the vertical portion 64d is inserted into the inner tank 6a of the tank 6 and opened upward, or FIG. As shown in FIG. 4B, the inverted U-shaped tube 64f is connected to the tip of the vertical portion 64d inserted into the inner tub 6a. In the example of FIG. 11, impurities are likely to enter the pressure guiding tube 63 from the opening end 64 e, but this is modified in the example of FIG.

Japanese Utility Model Publication No. 55-139425 JP 2000-310396 A

  In the liquefied gas tank, since the liquid level gauge is provided outside the tank, heat is input from the surface of the pressure guiding tube toward the inside thereof, and as a result, gas is introduced into the high pressure side pressure guiding tube connected to the liquid phase. Occur. That is, as shown in FIG. 11, a gas portion Y is formed near the liquid level gauge in the high pressure side pressure guiding pipe 63, and bubbles Z are generated in the liquefied gas in the vicinity of the distal end portion 64 due to heat input from the introduction pipe. . The same applies to the example of FIG. 12 (a), where a gas portion Y is formed from the top of the inverted U-shaped tube 64f to the liquid level gauge, and at the tip of the inverted U-shaped tube, Bubbles Z are generated in the liquefied gas.

  In the conventional liquefied gas tank in which the high-pressure side pressure guiding tube is provided as shown in FIGS. 11 and 12 (a), the pulsation is generated in the differential pressure detected by the differential pressure level gauge, so that the displayed liquid level is unstable. Tend to fluctuate. This phenomenon is unique to a liquefied gas tank, which cannot occur in a general liquid tank that is kept in a liquid phase at room temperature, but is presumed to be related to the generation of bubbles. That is, in the example of FIG. 11, when bubbles Z are generated in the vertical portion 64d of the pressure guiding tube 63 and the amount thereof changes, the pressure transmitted to the liquid level gauge also varies. In particular, when the bubbles Z become large or the bubbles Z are connected to each other to form a slag, the change in pressure becomes large. In the example of FIG. 12A, when a large amount of gas accumulates in the inverted U-shaped pipe 64f and escapes from the opening end 64g, the detected differential pressure (liquid level) changes as shown in FIG. 12B. it is conceivable that.

  The invention according to the claims makes it possible to reduce the above-described differential pressure fluctuation when a differential pressure type liquid level gauge is used for a liquefied gas tank, and to enable accurate and stable liquid level display.

The invention according to the claim is a liquefied gas tank to which a differential pressure type level gauge is connected via high pressure side and low pressure side pressure guiding pipes, and a tip portion including an open end of the high pressure side pressure guiding pipes, It is characterized by being inserted horizontally (including a case where it is almost horizontal, the same applies hereinafter) inside the vicinity of the bottom of the tank. For example, as shown in FIGS. 1 and 2, the tip of the high-pressure side pressure guiding tube inserted into the liquefied gas tank (in the case of a tank of two tanks, the inner tank) is leveled, and at least the portion inside the inner wall of the tank That is, there are no vertical parts or inverted U-shaped parts inside the tank. In addition, the pressure guiding pipe on the low pressure side connected to the gas phase in the tank may be provided with a tip including an open end in an arbitrary direction in the gas phase, and then connected to the differential pressure type level gauge via an arbitrary path. .
The above “near the bottom”, “inside”, and “almost horizontal” are as follows.
1) Near the bottom: This is the area near the bottom that is above the bottom of the tank and that does not cause any particular problems for the installation of the impulse tube. However, the distance X from the bottom surface of the tank to the pressure guiding tube is at least five times the tank bottom surface thickness t in order to avoid interference between the tank bottom surface and the welded portion of the pressure guiding tube.
2) Inside: Inserting the tip of the high pressure side impulse line into the tank not only so that the tip protrudes into the tank, but also the tip is flush with the inner surface of the tank. Includes inserting.
3) Nearly horizontal: Including not only horizontal but also slanted upward by 1 ° to 10 °.
When the high-pressure side pressure guiding tube or the like is attached as described above, fluctuations in the differential pressure between both the high-pressure side and low-pressure side pressure guiding tubes are suppressed, and the liquid level display by the differential pressure type liquid level gauge becomes accurate and stable. This has been confirmed by the test described later, but can be considered as follows. That is, if the tip of the high pressure side pressure guiding tube is horizontal, the head of the liquefied gas in the pressure guiding tube hardly changes even if bubbles are generated or the amount thereof is changed. If the tip of the pressure guiding tube is vertical as shown in FIG. 11, the head changes greatly depending on the amount of bubbles in the vertical portion, but if the tip of the pressure guiding tube is horizontal, the width of the change is small. . In addition, if there is an inverted U-shaped part at the tip of the vertical part as shown in FIG. 12, pressure fluctuation occurs due to gas accumulation or removal, but if the tip of the pressure guiding tube is horizontal, the gas Will not accumulate.
Further, as shown in FIG. 11 and FIG. 12A, when the vertical portion of the pressure guiding tube tip portion continues further downward from the bottom of the tank, the pressure drifts (displaces) due to the position of the liquid surface at that portion. As a result, it is necessary to correct the liquid level display by the liquid level gauge. However, if there is no vertical part at the tip, the pressure at the tip is accurately detected. You can know the correct liquid level. In addition, when the tip is horizontal, unlike the example of FIG. 11, there is no possibility that impurities enter from the opening end.

It is preferable that a plurality of small holes penetrating the wall surface of the pressure guiding tube are provided in the upper half (or a part thereof) at the tip of the high pressure side pressure guiding tube. The small hole is provided in the upper half near the opening end of the pressure guiding tube, for example, as shown in FIG.
If there is such a small hole, bubbles generated in the pressure guiding tube are quickly discharged into the tank through the small hole and are not easily accumulated in the pressure guiding tube. If bubbles do not easily accumulate in the pressure guiding tube, it is difficult for pressure changes in the pressure guiding tube due to the bubbles to escape, so that fluctuations in the differential pressure transmitted to the differential pressure level gauge are further suppressed.

It is also preferable that a short pipe having both ends opened is connected to the opening end of the tip portion of the high-pressure side pressure guiding tube with a longitudinal axis (vertical or almost vertical). The short pipe has a length of about 2 to 5 times the inner diameter, for example, as shown in FIG.
In the vertically oriented short pipe opened at both ends, when the bubbles generated in the pressure guiding pipe move upward and exit from the opening at the upper end, the liquefied gas flows from the opening at the lower end and tends to flow in the short pipe. Thereby, the bubbles in the pressure guiding tube are continuously and smoothly discharged without staying, and the pressure fluctuation in the pressure guiding tube due to the discharge is further reduced.
In order to continuously and smoothly discharge the bubbles in the high pressure side pressure guiding tube without stagnating, the vicinity of the tip of the pressure guiding tube is slightly upward as shown in FIG. It may be inclined. That is, the tip is inclined in a range of about 15 ° or less so that the portion close to the opening end is on the top.

A pot (concave portion) having a vertical (vertical or nearly vertical) wall surface is provided in a part of the bottom of the tank, and the tip of the high-pressure side pressure guiding tube extends from the vertical wall surface of the pot. It is also preferable that it is inserted into the tank. FIGS. 2A and 2B are examples.
When the pot portion as described above is provided at the bottom of the tank, the tip of the high-pressure side pressure guiding tube can be provided at an appropriate position on the tank bottom regardless of the shape of the tank. For example, even if the tank is horizontally long as shown in FIG.

The high-pressure side pressure guiding tube and the differential pressure type liquid level gauge may not have a damper for suppressing pressure fluctuation.
When a differential pressure type level gauge is installed in the liquefied gas tank, conventionally, a damper is provided in the high pressure side pressure guiding tube or differential pressure type level gauge to suppress changes in the liquid level display due to pressure fluctuations. It was. However, in the liquefied gas tank according to the invention, as described above, the fluctuation of the differential pressure is suppressed and the liquid level display is stabilized. If a damper is not provided, the structure for attaching the differential pressure type level gauge to the tank is greatly simplified, and the required cost is significantly reduced.

It is meaningful that the tank is filled with liquid nitrogen, liquid hydrogen, liquid oxygen, liquid helium or LNG.
These liquefied gases have a low boiling point of −160 ° C. or lower, and when a differential pressure type liquid level gauge is attached outside the tank, bubbles are actively generated inside the high pressure side pressure guiding tube. Therefore, if a pressure guiding tube is provided as in the prior art, the differential pressure fluctuation in the differential pressure type liquid level gauge is more severe, and it is difficult to obtain an accurate and stable liquid level display. Therefore, in the tank for the liquefied gas as described above, it can be said that the configuration of the invention exhibits a particularly significant operational effect.

  According to the liquefied gas tank of the invention, fluctuations in pressure transmitted to the differential pressure level gauge through the high pressure side and low pressure side pressure guiding pipes are suppressed, and therefore the liquid level display by the differential pressure level gauge is accurate and stable. Become. There is an advantage that it is not necessary to correct the drift caused by the length of the vertical portion and the like, and there is no risk of impurities entering from the opening end of the high pressure side impulse line.

Furthermore, by providing a pot having a vertical wall surface at the bottom of the tank, and inserting the tip of the high pressure side pressure guiding tube from the wall surface, the pressure guiding tube can be appropriately provided regardless of the shape of the tank. An indication can be obtained.
Further, if a damper for suppressing pressure fluctuation is not attached to the high pressure side pressure guiding tube and the differential pressure type liquid level gauge, the configuration can be simplified and the equipment cost can be reduced.
This is particularly significant when the above configuration is adopted for a tank for liquid nitrogen, liquid hydrogen, liquid oxygen, liquid helium or LNG.

FIG. 1A is a cross-sectional view showing an example of a liquefied gas tank according to the invention, and FIGS. 1B and 1C are views showing a tip portion of a high-pressure side impulse line as a detail in FIG. is there. FIG. 2A is a cross-sectional view showing another example of the liquefied gas tank according to the invention, and FIG. 2B is a view showing a tip portion of a high-pressure side impulse line as a detail of a portion b in FIG. is there. 3A and 3B are cross-sectional views showing an example different from the example of FIGS. 1 and 2 with respect to the distal end portion of the high-pressure side pressure guiding tube. It is sectional drawing and the specification list which show the outline | summary of an installation about the experiment conducted using the various types of high pressure side impulse lines. FIG. 5 is a diagram showing a result of an experiment performed by the facility of FIG. 4 and showing a differential pressure detected when a type 1 tube is used at the tip of the high pressure side pressure guiding tube. FIG. 5 is a diagram showing a result of an experiment performed by the facility of FIG. 4 and showing a differential pressure and the like detected when a type 2 tube is used at the tip of the high-pressure side pressure guiding tube. FIG. 5 is a diagram showing a result of an experiment performed by the facility of FIG. 4 and showing a differential pressure detected when a type 3 tube is used at the tip of the high pressure side pressure guiding tube. FIG. 5 is a diagram showing a result of an experiment performed by the facility of FIG. 4 and showing a differential pressure detected when a type 4 (invention) is used at the tip of a high-pressure side pressure guiding tube. It is a result of the experiment conducted by the facility of FIG. 4, and is a diagram showing the liquid level accuracy detected when each of the tip portions is used. It is sectional drawing which shows the conventional general tank for liquefied gas. It is sectional drawing which shows the form of the front-end | tip part of the high voltage | pressure side impulse line used for the conventional tank for liquefied gas. FIG. 2A is a cross-sectional view showing the form of the tip of a high-pressure side pressure guiding tube used in a conventional liquefied gas tank, which is different from that of FIG. 10, and FIG. It is a schematic diagram which shows the change of the differential pressure | voltage which generate | occur | produces when using a pressure pipe.

  1 to 9 show an embodiment of the invention. First, FIG. 1 to FIG. 3 respectively show the configuration of a liquefied gas tank according to the invention.

  A liquefied gas tank 1 shown in FIG. 1 has a vertical cylindrical shape for holding a liquefied gas X such as liquid nitrogen or liquid hydrogen, and is provided as an inner tank 1a and an outer tank 1b and a heat insulating layer therebetween. And a vacuum layer 1c. In order to know the amount of the internal liquefied gas, a differential pressure type liquid level gauge 10 is attached to the outside of the tank 1 and connected to the inside of the inner tank 1a by the pressure guiding pipes 11 and 13 on the low pressure side and the high pressure side. That is, the low pressure side pressure guiding tube 11 is passed through the vacuum layer 1c from a portion close to the liquid level gauge 10, and penetrates the wall surface of the inner tank 1a so that the tip 12 opens to the upper part of the gas phase. Yes. One high pressure side pressure guiding tube 13 is also arranged in the vacuum layer 1c from the vicinity of the liquid level gauge 10, and the front end portion 14 penetrates the wall surface of the inner tank 1a and opens to the bottom of the liquid phase. Yes. Similar to the example shown in FIG. 10, the liquid level gauge 10 detects the difference in pressure transmitted to both the pressure guiding pipes 11 and 13 and displays the differential pressure as the liquid level of the liquefied gas X. As the pressure guide tubes 11 and 13, thin tubes (metal tubes or the like) having a diameter (inner diameter) of about 5 to 15 mm are used in order to reduce heat input to the liquefied gas.

In the example of FIG. 1, the distal end portion 14 of the high-pressure side pressure guiding tube 13 is horizontal, and the vertical wall surface of the inner tank 1 a in the tank 1 is penetrated and attached. The protruding length from the wall surface of the inner tank 1a to the opening end 14a is, for example, about 0 to 100 mm. The front end portion 14 that is leveled is connected to the liquid level meter 10 by continuing a vertical portion whose side closer to the level meter 10 is higher, and the side closer to the opening end is on the upper side as in the example of FIG. Such vertical parts are not provided.
1B, a plurality of small holes 14b penetrating the wall surface of the pressure guiding tube 13 are formed in a part of the upper half portion of the tip portion 14 of the pressure guiding tube 13 near the opening end 14a. Yes. The small holes 14b have a diameter of about 1 to 3 mm, and the number thereof is about 5 to 30, for example.

In this example, since the distal end portion 14 of the pressure guiding tube 13 is horizontal, the pressure in the pressure guiding tube 13 hardly changes even if bubbles are generated or the amount of bubbles is changed. Therefore, the variation in the differential pressure between the high pressure side pressure guiding tube 13 and the low pressure side pressure guiding tube 11 is small, and the liquid level display by the differential pressure type liquid level gauge becomes accurate and stable.
Further, since there are a plurality of small holes 14 b in the tip end portion 14, the generated bubbles are smoothly discharged into the tank 1 through the small holes 14 b and are not easily accumulated in the pressure guiding tube 13. Therefore, the pressure change in the pressure guiding tube 13 due to the escape of the bubbles is small, and the fluctuation of the differential pressure transmitted to the level gauge 10 is further suppressed. Since the fluctuation of the differential pressure is suppressed by the action of the distal end portion 14 of the pressure guiding tube 13, it is not necessary to attach a damper for suppressing pressure fluctuation to the pressure guiding tubes 11, 13 or the differential pressure type level gauge 10.

  The liquefied gas tank 2 shown in FIGS. 2A and 2B also holds the liquefied gas X, and has a horizontal cylindrical shape with a horizontal center line. This tank 2 is also composed of an inner tank 2a, an outer tank 2b, and a vacuum layer 2c as a heat insulating layer. A differential pressure type liquid level gauge 20 is attached to the outside and is connected to the gas phase and the liquid phase bottom in the inner tank 2a by low pressure side and high pressure side pressure guiding pipes 21 and 23, respectively, as in the example of FIG. The diameters of the pressure guiding tubes 21 and 23 are the same as in the example of FIG.

In this example, as shown in FIG. 2 (b), a pot 2d having a vertical wall surface is provided in a part of the bottom of the tank 2, and the distal end portion 24 of the high-pressure side impulse line 23 is placed inside by passing through the vertical wall surface. It protrudes into the tank 2a. The front end portion 24 placed in the inner tank 2a is horizontal including the opening end 24a, so that about 0 to 100 mm protrudes into the inner tank 2a. The horizontal tip 24 is connected to the liquid level gauge 20 by continuing a horizontal portion as shown in FIG. A vertical portion or the like such that the side close to the opening end 24 a is on the upper side is not provided in the pressure guiding tube 23.
Also in the tip portion 24 of the pressure guiding tube 23, as shown in FIG. 2B, a plurality of small holes 24b penetrating the wall surface of the pressure guiding tube 23 are formed in the upper half of the portion near the opening end 24a. . The diameter and number of the small holes 24b are the same as in the example of FIG.

  In the example of FIG. 2 also, since the tip 24 is horizontal and there are a plurality of small holes 14b in the upper half, the pressure change in the pressure guiding tube 13 is suppressed, and the differential pressure transmitted to the differential pressure level gauge 10 Therefore, the liquid level display by the liquid level gauge 10 is accurate and stable.

In order to smoothly release bubbles generated in the high pressure side pressure guiding tube into the tank, the tip of the high pressure side pressure guiding tube is not only made as shown in FIGS. 1B and 2B but also in FIG. It is also preferable to do as a) or (b).
In the example of FIG. 3A, short pipes 34 c that are open at both ends are connected to an open end 34 a at the tip 34 of the high-pressure side pressure guiding pipe 33 in the vertical direction. The short tube 34c may have an inner diameter that is approximately the same as that of the pressure guiding tube 33 and has a length that is approximately 2 to 5 times the inner diameter. In the short pipe 34c, the flow of the liquefied gas is generated with the upward movement of the bubble Z. Therefore, the bubble Z in the pressure guiding tube 33 is continuously discharged smoothly, and the pressure fluctuation in the pressure guiding tube 33 is effectively reduced. It is suppressed.

  In the example of FIG. 3B, the tip end portion 44 of the high-pressure side pressure guiding tube 43 is inclined upward by about 1 to 10 ° so that the portion near the opening end 44a is substantially horizontal. This also makes it easy for the bubbles Z to be continuously and smoothly discharged, and the pressure fluctuation in the pressure guiding tube 43 accompanying the movement of the bubbles Z is reduced.

  4 to 9 show an experiment conducted for confirming the measurement accuracy of the differential pressure type level gauge. First, FIG. 4 is a longitudinal sectional view of a small liquefied gas tank 3 used in the experiment, along with the specifications of the low pressure impulse line 51 and the high pressure side impulse line 53. The illustrated tank 3 has an inner tank 3a having a diameter of 200 mm and a height of 400 mm accommodated in an outer tank 3b and provided with a vacuum layer 3c therebetween. The inner tank 3a stores liquid nitrogen as a test solution. . A low pressure impulse line 51 is connected to the gas phase portion in the inner tank 3a, and a high pressure impulse line 53 is connected to the liquid phase part at the bottom of the inner tank 3a. Omitted).

Tables 1 and 2 show an outline of the experimental apparatus main body and the measurement system used. Point sensors for temperature measurement are arranged at a large number of locations in the inner tank 3a, and the measurement accuracy by the differential pressure type liquid level gauge is evaluated based on the data from the point sensors.

Four types of high pressure side pressure guiding pipes 53 are prepared as tip portions to be attached to the liquid phase bottom of the inner tank 3 a, and any one of them is connected to the pressure guiding pipe 53 for use. The four types are as shown in FIG. That is,
Type 1: Front end 54A in which an inverted U-shaped tube with a bending radius of 70 mm is connected to the tip of the vertical portion
Type 2: Tip portion 54B in which an inverted U-shaped tube having a bending radius of 30 mm is connected to the tip of the vertical portion.
Type 3: Front end portion 54C having a vertical portion following the opening end facing upward
Type 4: Horizontal tip 54D attached to the side wall of the inner tank 3a (according to the present invention)

FIG. 5 to FIG. 8 show differential pressure fluctuations (that is, changes in the liquid level display) of the differential pressure type liquid level gauge when the above-mentioned types are connected as the distal end portion of the high pressure side pressure guiding tube 53.
When Type 1 and Type 2 tip parts (54A and 54B) are used, the differential pressure is about 1-2 minutes as shown in FIGS. 5 and 6, respectively, and about 0.1-0.5 kPa. It oscillated greatly with the amplitude of. The period / amplitude seems to be affected by the movement of bubbles based on the bending shape of the tip, and the period when using Type 1 with a large bending radius is about twice that of Type 2 with a small bending radius. is there. Further, when the type 3 tip (54C) was used, as shown in FIG. 7, it vibrated with an amplitude of about 0.05 kPa with a shorter period than in the case of types 1 and 2. However, when the tip part (54D) of the type 4 according to the invention is used for the high pressure side pressure guiding tube 53, as shown in FIG. 8, the vibration of the differential pressure is extremely small as compared with other types. In the case of this type 4, it is considered that the liquid level accuracy is good because bubbles are quickly removed, and the type 3 type picks up the liquid level vibration due to the bubbles in the vertical part, so the accuracy is lower than the type 4 type. Imagine.

  FIG. 9 shows measured values of the liquid level drift (deviation) indicated by the differential pressure type liquid level gauge when the above-mentioned types of tip portions are used. Separately from the experiments of FIGS. 5 to 8, in the tank 3 of FIG. 4, the liquid surface height of the inner tank 3 a is set to 300 mm, and the tip of each type is connected to the tip of the high-pressure side impulse line 53. The result of FIG. 9 was obtained by drawing the display data of the differential pressure type level gauge in the case of.

Table 3 shows the average value of the drift of the display liquid surface shown in FIG. When the type 4 tip (54D) according to the invention was used, more favorable results were obtained with respect to drift than when other tips were used.

1 ・ 2 ・ 3 Tank for liquefied gas 2d Pot 10 ・ 20 Differential pressure level gauge 11 ・ 21 ・ 51 Low pressure side pressure guiding tube 13 ・ 23 ・ 33 ・ 43 ・ 53 High pressure side pressure guiding tube 14 ・ 24 ・ 34 ・ 44 ・ 54 (54A-54D) Tip portion 14a / 24a / 34a / 44a Open end 14b / 24b Small hole 34c Short tube

Claims (5)

A tank for liquefied gas to which a differential pressure type level gauge is connected via a pressure guiding pipe,
The liquefied gas tank has an inner tank and an outer tank,
The tip including the open end of the high pressure side pressure guiding tube penetrates the wall surface of the inner tank and protrudes into the inner tank, and is inserted horizontally or almost horizontally into the inside of the vicinity of the bottom of the inner tank ,
A liquefied gas tank , wherein a plurality of small holes penetrating the wall surface of the pressure guiding tube are provided in an upper half portion at a distal end portion of the high pressure side pressure guiding tube . A tank for liquefied gas to which a differential pressure type level gauge is connected via a pressure guiding pipe,
The liquefied gas tank has an inner tank and an outer tank,
The tip including the open end of the high pressure side pressure guiding tube penetrates the wall surface of the inner tank and protrudes into the inner tank, and is inserted horizontally or almost horizontally into the inside of the vicinity of the bottom of the inner tank,
A liquefied gas tank, characterized in that a short pipe having both ends opened is vertically connected to an open end at a tip of the high pressure side pressure guiding pipe . A pot having a vertical wall surface is provided at a part of the bottom of the inner tank, and the tip of the high-pressure side impulse line is inserted into the inner tank from the vertical wall surface of the pot. The liquefied gas tank according to claim 1 or 2 . The liquefied gas tank according to any one of claims 1 to 3 , wherein the high-pressure side pressure guiding tube and the differential pressure type liquid level gauge do not have a damper for suppressing pressure fluctuation. The liquefied gas tank according to any one of claims 1 to 4 , wherein any one of liquid nitrogen, liquid hydrogen, liquid oxygen, liquid helium or LNG is contained.

Images