JPH09273648A - Emergency cutoff device of liquid storage tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent drinking water stored in a liquid storage tank from flowing out by sensing an earthquake by making use of waves by the slashing phenomenon to be generated with the earthquake. SOLUTION: Sensing mechanisms 5 (sensors 52, 53, 54) for sensing that the liquid level is abnormally raised caused by the sloshing phenomenon when the sloshing phenomenon is generated with an earthquake are provided on the peripheral edge of a liquid storage tank 2, the abnormal rising of the liquid level is sensed by the sensing mechanisms 5 (sensors 52, 53, 54) when the liquid level on the peripheral edge in the liquid storage tank 2 is raised to the set height or more, and an opening and closing valve (a solenoid valve 42) arranged on a supplying pipe 3 communicated with a takeoff port 2a opened on the lower part of the liquid storage tank 2 is operated in the closing position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emergency shutoff device for a storage tank for preventing liquid such as drinking water stored in the storage tank from flowing out due to an earthquake.

[0002]

2. Description of the Related Art Conventionally, there has been known an emergency shutoff valve which automatically shuts off water flow by closing a flow passage provided in the middle of a pipe when the pipe is damaged by an earthquake. For example, as described in Japanese Patent Laid-Open No. 5-248552, the occurrence of an earthquake is detected by a well-known earthquake sensor, and the detection signal activates the valve element of an emergency shutoff valve provided in the middle of the pipe. The water flow is automatically cut off.

[0003]

However, the above-mentioned earthquake detector may detect a vibration other than an earthquake, for example, a vibration caused by a large vehicle, and may malfunction. There is a possibility that the valve body of (3) may be activated to shut off the supply of liquid such as drinking water.

The present invention has been made in view of the above problems, and utilizes the sloshing phenomenon that accompanies an earthquake to detect an earthquake and prevent the outflow of drinking water or the like stored in a liquid storage tank. (EN) An emergency shutoff device for a liquid storage tank that can be reliably prevented.

[0005]

The present invention comprises a liquid storage tank for storing a liquid such as drinking water, an outlet opening at the bottom of the liquid storage tank, and an on-off valve communicating with the outlet. It consists of a supply pipe and a sensing mechanism that senses an abnormal rise in liquid level or hydraulic pressure due to the sloshing phenomenon when an earthquake causes a sloshing phenomenon. If one or more units are placed near it and the liquid level at the peripheral edge of the liquid storage tank rises above the set height, the sensing mechanism senses an abnormal rise in the liquid level or an abnormal rise in hydraulic pressure, and opens and closes as described above. The gist is that the valve is closed directly or indirectly.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of an emergency shutoff device 1 for a liquid storage tank of the present invention. The emergency shutoff device 1 in this embodiment is used for tap water, tap water, fire water, etc. A liquid storage tank 2 for storing various liquids, an outlet 2a opening in the lower portion of the liquid storage tank 2, a supply pipe 3 communicating with the outlet 2a and having an opening / closing valve 4, and sloshing accompanying an earthquake When a phenomenon occurs, it comprises a sensing mechanism 5 that senses the sloshing phenomenon and outputs a sensing signal, and a control panel 6 that receives the sensing signal from the sensing mechanism 5 and controls the on-off valve 4.

The liquid storage tank 2 is installed in a hospital, a school, a high-rise house, an apartment house or a factory. In this embodiment, an elevated water tank installed on the roof of a building is exemplified. . That is, this storage tank 2 is
1 is connected to a water receiving tank (not shown), and a liquid is pumped up via a pump 22 arranged in a pumping pipe 21. The overflow pipe 23 and the drain valve 24 are provided at the top and bottom of the liquid storage tank 2, respectively.
Is connected to the drain pipe 25. Further, the supply pipe 3 for supplying the liquid stored in the liquid storage tank 2 to a desired place is a piston type stop serving as an opening / closing valve 4 directly connected to an outlet 2a opening at a lower portion of a side wall of the liquid storage tank 2. It is connected to the valve 41.

The piston type stop valve 41 includes a valve body 41a, an air cylinder 41b having a piston rod connected to the valve body 41a, and the air cylinder 4
1b, a spring 41c for urging the valve body 41a to the closed position of the supply pipe 3, and a solenoid valve 41e arranged in an air pipe connecting the air cylinder 41b and the gas cylinder 41d. The valve 41e opens the air pipe by a control signal from the control panel 6. As a result, the air cylinder 41b is constantly supplied with compressed gas such as air or an inert gas (for example, helium gas or nitrogen gas) from the gas cylinder 41d, and the valve body 41a.
Is continuously held at a position where the supply pipe 3 is opened against the biasing force of the spring 41c.

By the way, a pressure sensor 51 as a sloshing sensing mechanism 5 is provided at the peripheral edge of the ceiling wall and the lower peripheral edge of the side wall of the liquid storage tank 2. Although not shown in detail, the pressure sensor 51 is a pressure converter that converts a hydraulic pressure into an electric signal, and outputs a detection signal to the control panel 6 when a hydraulic pressure above a set value is detected. Is. In addition, for example, as the pressure sensor 51, a small pressure transducer PGM-C (pressure receiving surface diameter 5.5 mm, measurement range ^{2 to} 10 kgf / cm ² ) manufactured by Kyowa Denki Co., Ltd. is preferably used.

Here, the sloshing will be described. Sloshing is a rocking phenomenon of the liquid in the container that occurs during an earthquake, and the rocking of the liquid is amplified as the earthquake continues. Although it cannot be generally stated depending on the positional relationship with the epicenter and the installation conditions of the liquid storage tank 2, for example, when the liquid storage tank 2 has a very elongated rectangular shape as shown in FIG. Often, large waves make a round trip in the longitudinal direction. Further, as shown in FIG. 2B, when the planar shape of the liquid storage tank 2 is close to a square or has a large installation area, large waves reciprocate between the opposite corners. As a result, a hydrostatic pressure larger than the hydrostatic pressure of the liquid stored in the liquid storage tank 2 at the normal high level H acts on the ceiling wall, the side wall, and the bottom wall, and the wave impact force is applied. . For example, in the case of 100 gal acceleration observed at Kansai Airport during the Great Hanshin-Awaji Earthquake, 4mW x 6mL x
When the static head is 2.1 m in the 2.5 mH storage tank 2,
At the maximum of sloshing, a water pressure of 4 mH was measured at the bottom.

Incidentally, instead of the sliding device using the air cylinder 41b constituting the piston type stop valve 41, a sliding device using a diaphragm can be used, and a hydraulic cylinder can also be adopted. Further, a butterfly valve or a ball valve of a cylinder valve type may be adopted, or a cylinder type valve using a rack and a pinion may be adopted.

Next, the operation of the emergency shutoff device 1 will be described. Normally, the liquid level of the liquid stored in the liquid storage tank 2 (high-placed water tank) fluctuates within a set range. That is, when the liquid level of the liquid stored in the liquid storage tank 2 is lowered to the low level L due to the consumption of the liquid, a sensor (not shown) detects the liquid level and operates the pump 22 to set the water receiving tank. The liquid stored in 1 is sent to the liquid storage tank 2 installed at a high place or the like via the pumping pipe 21. On the other hand, when the liquid is fed, the liquid level of the liquid stored in the liquid storage tank 2 rises, and when the liquid level reaches a high level H, the sensor detects the liquid level and stops the operation of the pump 22. Also,
The valve body 41a of the piston type stop valve 41 is usually
The liquid in the liquid storage tank 2 (high water tank) placed at a high position at the position where the supply pipe 3 is opened goes to a low place via the supply pipe 3.
It is supplied using the height difference.

When an earthquake occurs and a large wave due to the sloshing phenomenon associated with the earthquake reciprocates between the opposing side walls or between the opposing corners, the liquid stored in the liquid storage tank 2 is at a high level H. A hydrostatic pressure greater than the hydrostatic pressure acts on the ceiling wall, side walls and bottom wall. This abnormal rise in pressure is detected by the pressure sensor 51, and the detection signal is output to the control panel 6. The control panel 6 that receives this sensing signal
The solenoid of the solenoid valve 41e and the operation of the pump 22 are stopped. Here, the electromagnetic valve 41e returns to the position where the air pipe is closed, and the pump 22 stops the water supply from the water receiving tank to the liquid storage tank 2. Further, the control panel 6 turns on the alarm lamp 61 and sounds the alarm buzzer 62 to notify the abnormality. When the solenoid valve 41e returns to the position where the air pipe is closed, the supply of the compressed gas into the air cylinder 41b is cut off, and the valve body 41a closes the supply pipe 3 by the urging force of the spring 41c. Pressed into position.

As a result, when an earthquake causes a large wave due to the sloshing phenomenon and an abnormal rise in hydraulic pressure is detected, the supply pipe 3 and the equipment arranged outside the liquid storage tank 2 are damaged. Even if it does not occur, the piston type stop valve 41 will promptly close the supply pipe 3. In this way, the outflow of the liquid stored in the liquid storage tank 2 is reliably prevented, and the liquid is secured in the liquid storage tank 2 as long as the liquid storage tank 2 is not damaged, so that the demand for the liquid after the earthquake can be met. You can

Reference numeral B denotes a storage battery for a power failure, and when a power failure occurs due to an earthquake, the control panel 6 which receives a detection signal from the pressure sensor 51 lights an alarm lamp 61 and sounds an alarm buzzer 62 to store a liquid. Solenoid valve 4 when tank 2 is not operating normally
Notify that the solenoid of 1e and the pump 22 have stopped operating.

When an abnormal increase in hydraulic pressure due to an earthquake is detected, the solenoid valve 41e is opened by the operation of the power source or the storage battery B for power failure, and compressed gas is supplied into the air cylinder 41b to open the on-off valve 4. The configuration may be closed. That is, the compressed gas is supplied from the gas cylinder 41d to the air cylinder 41 only when an abnormal increase in hydraulic pressure is detected due to an earthquake.
It may be configured such that the on-off valve 4 is closed by supplying it to the inside of b.
Anything can be used here as long as it can store electricity.

If the supply pipe 3 near the liquid storage tank 2 is damaged, damage will spread to the liquid storage tank 2 and cracks will occur, and the liquid will easily flow out. It is desirable to provide the flexible tube 31 near the stop valve 41.

When the drinking water remaining in the liquid storage tank 2 is to be taken out after the earthquake, the liquid can be pumped out from the manhole of the liquid storage tank 2 or connected to the bottom of the liquid storage tank 2. Water can be taken by opening the drainage valve 24 that is installed.

Further, the solenoid valve 41e is opened (or closed) by using the storage battery B for power failure and the on-off valve 41 is opened by manual operation, so that the liquid can be easily taken out from the supply pipe 3 even at the time of power failure. You can

Next, a second embodiment of the emergency shutoff device 1 for a liquid storage tank according to the present invention will be described with reference to FIG. In addition, in 2nd Embodiment and the following embodiments, the same code | symbol shall be used for the same member as 1st Embodiment.

In this embodiment, a water receiving tank is exemplified as the liquid storage tank 2. An introduction pipe 27 having a constant water level valve 26 disposed therein is introduced into the liquid storage tank 2 through the ceiling wall of the liquid storage tank 2, and the constant water level valve 26 is provided in the liquid storage tank 2. The ball tap 26a is opened and closed in conjunction with the operation of the ball tap 26a.

Further, the on-off valve 4 arranged in the supply pipe 3 is
Although it is composed of the electromagnetic valve 42, it may be a motor valve.

On the other hand, in the liquid storage tank 2, as a sloshing detection mechanism 5, sensors 52 and 53 composed of electrode rods are provided.
Are provided on the opposite peripheral edges of the ceiling wall,
Sensors 54 made of electrodes are provided on the upper and lower peripheral edges of one side wall. In this example, the position of the liquid level is detected by detecting the energization or interruption of the current due to the change of the liquid surface of the conductive liquid.

The sensor 52 also serves as a sensor for detecting an abnormal liquid level during normal operation.

That is, since the constant water level valve 26 arranged in the introduction pipe 27 is designed to open and close in conjunction with the operation of the ball tap 26a provided in the liquid storage tank 2, the inside of the liquid storage tank 2 is The liquid level is normally maintained between H and L, which is within an appropriate range, by repeatedly consuming and returning to the original level. However, when the liquid level in the liquid storage tank 2 becomes too high and reaches H ', or when it becomes too low and reaches L', the abnormality is detected, the alarm lamp 61 is turned on, and the alarm buzzer is turned on. 62 is sounded to notify the abnormality. When the water level reaches L ″, the pump 22 is stopped.

Next, the operation of the emergency shutoff device 1 according to the second embodiment will be described.

The liquid stored in the liquid storage tank 2 is taken out by the pump 22 and supplied to the elevated water tank on the roof of the building or the elevated platform, and when the liquid level is lowered, the liquid level is reduced. The float 26b of the ball tap 26a is lowered,
The constant water level valve 26 that is interlocked with the ball tap 26a is opened. In this way, a liquid such as tap water is introduced into the liquid storage tank 2 via the introduction pipe 27 and the constant water level valve 26. Further, when it is detected that the liquid level in the elevated water tank or the like has risen to reach a certain level and the pump 22 stops operating via the control panel 6, liquid such as tap water is introduced into the introduction pipe 27 and the constant water level valve. By being introduced into the liquid storage tank 2 via 26, the liquid level in the liquid storage tank 2 gradually rises. Then, when the float 26b of the ball tap 26a rises following the rise of the liquid level and reaches the high level H, the constant water level valve 26 is closed and the introduction of the liquid thereafter is cut off.

When an earthquake occurs here and a large wave due to the sloshing phenomenon accompanying the earthquake reciprocates between the opposing side walls or between the opposing corners, the liquid stored in the liquid storage tank 2 is at a high level H. It rises abnormally beyond the liquid level at that time. This abnormal rise in liquid level is detected by the sensors 52, 53, 54.
Senses and outputs the sensed signal to the control panel 6. Upon receiving this detection signal, the control panel 6 supplies (or stops) the control signal to the solenoid of the solenoid valve 42 and the pump 22 to operate the solenoid valve 42 provided in the supply pipe 3 at the position to be closed. The pump 22 is stopped, the alarm lamp 61 is turned on, and the alarm buzzer 62 is sounded to notify the abnormality.

As a result, when an earthquake causes a large wave due to the sloshing phenomenon and an abnormal rise in the liquid level is detected, the supply pipe 3 and the equipment disposed outside the liquid storage tank 2 are damaged. Even if it does not occur, the electromagnetic valve 42 will promptly close the supply pipe 3. In this way, the outflow of the liquid stored in the liquid storage tank 2 is reliably prevented, and the liquid is secured in the liquid storage tank 2 unless the liquid storage tank 2 is damaged.

Furthermore, the emergency shutoff device 1 for the liquid storage tank of the present invention
3rd Embodiment of this is demonstrated based on FIG.

In the case of the emergency shutoff device 1 according to this embodiment, as the sloshing phenomenon sensing mechanism 5, sensors 52 and 53 composed of electrode rods are provided at two adjacent corners of the ceiling wall, and the opening / closing operation is performed. Solenoid valve 4 as valve 4
2 is provided in the supply pipe 3.

Also in this embodiment, when a large wave due to the sloshing phenomenon associated with an earthquake reciprocates between the opposite side walls or between the opposite corners, the liquid level that exceeds the liquid level at the high level H abnormally rises. As a result of the sensors 52 and 53 sensing and the electromagnetic valve 42 closing the supply pipe 3 via the control panel 6, the outflow of the liquid stored in the liquid storage tank 2 is reliably prevented.

A fourth embodiment of the emergency shutoff device 1 for a liquid storage tank according to the present invention will be described with reference to FIG.

In the case of the emergency shutoff device 1 according to this embodiment, as the sloshing phenomenon sensing mechanism 5, the sensors 52 and 53 made of electrode rods are arranged at the four corners of the ceiling wall, and as the on-off valve 4, Solenoid valve 42 is liquid storage tank 2
It is directly connected to the outlet opening on the side wall of the. In addition, in the case of this example, the planar shape of the liquid storage tank 2 is close to a square, and it is expected that the waves due to sloshing will reciprocate between the two opposite corner portions. In other words, the sensing mechanism 5 does not need to be arranged in all corners of the ceiling wall, and the corners in either direction are adjacent to each other at least so that waves can be sensed even if waves due to sloshing oscillate. It may be installed in two corners.

In addition, in this embodiment, ventilation pipes 7 are provided along the four corners of the ceiling wall. This ventilation pipe 7
Although not shown in detail, is composed of a pipe and a cap, and is erected on a hole formed in a corner portion of the ceiling wall. That is, the inside and outside of the liquid storage tank 2 are in communication with each other through the pipe and the hole. Here, when a negative pressure is generated inside the liquid storage tank 2 due to a large movement of waves due to sloshing, the air outside the liquid storage tank 2 is introduced into the liquid storage tank 2 through the ventilation pipe 7, and the negative pressure is increased. Since it is eliminated, it is possible to prevent the side wall and the ceiling wall from being deformed or collapsed due to the generation of the negative pressure.

The operation in this embodiment is the same as in the case of the third embodiment, and the description thereof is omitted.

Next, a fifth embodiment of the emergency shutoff device 1 for a liquid storage tank of the present invention will be described with reference to FIG.

In the case of the emergency shutoff device 1 according to this embodiment, a pressure sensor 51 is arranged at a corner portion of the ceiling wall as the sloshing phenomenon detection mechanism 5, and the open / close valve 4 is a cylinder valve type butterfly valve. 43 is arranged in the supply pipe 3. The cylinder valve type butterfly valve 43 has a solenoid valve 43 similar to the piston type stop valve 41 in the first embodiment.
The operation is indirectly controlled via e. That is, the butterfly valve 43 of the cylinder valve type has a valve body 43a.
An air cylinder 43b having a sliding plate connected to the valve body 43a, a spring 43c provided on the air cylinder 43b for urging the valve body 43a to the open position of the supply pipe 3, and an air cylinder 43b. Gas cylinder 4
It is composed of an electromagnetic valve 43e arranged in an air pipe connecting between 3d. Normally, the electromagnetic valve 43e closes the air pipe when a control signal from the control panel 6 is cut off. As a result, the valve body 43a is supplied to the supply pipe 3 by the urging force of the spring 43c.
Is open.

In the case of this embodiment, when a large wave due to the sloshing phenomenon associated with an earthquake reciprocates between the opposite side walls or between the opposite corners, when the liquid stored in the liquid storage tank 2 is at a high level H. A hydrostatic pressure greater than the hydrostatic pressure acts on the ceiling wall, side walls and bottom wall. This abnormal rise in pressure is detected by the pressure sensor 51, and the detection signal is output to the control panel 6. Control panel 6 that received this sensing signal
Supplies the control signal to the solenoid of the solenoid valve 43e to operate the solenoid valve 43e to the open position of the air pipe, and stops the supply of the control signal to the pump 22 to stop the pump 2
2 is stopped, the alarm lamp 61 is turned on, and the alarm buzzer 62 is sounded to notify the abnormality. For this reason,
Compressed gas is supplied from the gas cylinder 43c to the air cylinder 43b, and the valve body 43a operates to a position where the supply pipe 3 is closed against the biasing force of the spring 43c.

Therefore, if the pressure sensor 51 detects a liquid pressure above the set value due to the wave caused by the sloshing phenomenon, the supply pipe 3 is closed and the liquid stored in the liquid storage tank 2 is surely discharged. To be prevented.

On the other hand, when the inside of the liquid storage tank 2 is divided into a plurality of parts by the partition plate 8, as shown in FIG. 7, sloshing is applied to the adjacent corners of the ceiling wall of each divided tank. The sensing mechanism 5 may be provided. Since it is considered that sloshing due to an earthquake occurs at the same time in each tank, it is not always necessary to provide the sensing mechanism 5 for each of the divided tanks. The sensing mechanism 5 may be provided at the adjacent corners of the ceiling wall. Further, in the case where the supply pipe 3 provided with the opening / closing valve 4 is provided for each of the divided tanks, the sensing mechanism 5
When the sloshing phenomenon is detected by the control panel 6,
It is necessary to operate each on-off valve 4 at the open chain position of the supply pipe 3.

Further, the flow regulating walls 91, 9 are provided inside the liquid storage tank 2.
When two or the like are provided, the sloshing detection mechanism 5 may be provided at one or more corners of the ceiling wall formed by providing the straightening wall.
As shown in FIG. 8, a sloshing sensing mechanism 5 may be provided at a corner portion adjacent to one end of the liquid storage tank 2.

As the sloshing phenomenon sensing mechanism 5, the pressure sensor 51 described in the above embodiment is used.
It is not limited to only the sensors 52, 53, 54. For example, as the sensing mechanism 5, as shown in FIG. 9A, a float switch that senses a rise in liquid level above a certain level and turns a micro switch on and off may be adopted. ), A float switch that emits a detection signal when the float that moves up and down following the rise of the liquid level senses an abnormal rise of the liquid level may be employed, as shown in FIG. 9 (c). Alternatively, the distance between the sonic wave transmitter / receiver and the liquid surface may be measured by a sound wave, and a rise in the liquid level above a certain level may be sensed to output a sensing signal.
As shown in (d), a pair of opposing side walls or adjacent side walls are provided with wave transmitters for transmitting light or sound waves and wave receivers for receiving waves, respectively, to detect a rise in liquid level above a certain level. It may be one that outputs a sensing signal, and in any case, it may be one that senses an abnormal rise in the liquid surface or liquid pressure due to sloshing.

[0045]

As described above, according to the present invention, a liquid storage tank for storing a liquid such as drinking water, an outlet opening at the bottom of the liquid storage tank, and an opening / closing valve communicating with the outlet. And a sensing mechanism that senses an abnormal rise in liquid level or abnormal pressure due to the sloshing phenomenon when a sloshing phenomenon occurs due to an earthquake. If one or more parts are placed at or near the section, and the liquid level at the peripheral edge in the liquid storage tank rises above the set height, the sensing mechanism senses an abnormal rise in the liquid level or an abnormal rise in hydraulic pressure, Since the on-off valve is closed directly or indirectly, when an earthquake occurs and a large wave due to the sloshing phenomenon occurs, and an abnormal rise in liquid level or abnormal rise in hydraulic pressure is detected, promptly Open / close valve for supply pipe Even if the supply pipes and equipment installed outside the liquid storage tank are broken, the liquid stored in the liquid storage tank is reliably prevented from flowing out, and unless the liquid storage tank is damaged, the liquid storage tank Since the liquid is secured in, it is possible to meet the demand for the liquid after the earthquake.

Further, when a sloshing phenomenon occurs due to an earthquake, an abnormal increase in the liquid level or an abnormal increase in the liquid pressure due to the sloshing phenomenon is detected to close the on-off valve to prevent the outflow of the liquid. So, for example,
There is no risk of erroneous operation such as shutting off the supply of liquid such as drinking water even when there is no earthquake, by activating the valve body of the emergency shutoff valve by sensing the vibration of a large vehicle.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of an emergency shutoff device for a liquid storage tank according to the present invention.

FIG. 2 is a schematic diagram illustrating a wave caused by sloshing generated in a liquid storage tank.

FIG. 3 is a sectional view showing a second embodiment of an emergency shutoff device for a liquid storage tank according to the present invention.

FIG. 4 is a perspective view showing a third embodiment of an emergency shutoff device for a liquid storage tank according to the present invention.

FIG. 5 is a perspective view showing a fourth embodiment of an emergency shutoff device for a liquid storage tank according to the present invention.

FIG. 6 is a perspective view showing a fifth embodiment of an emergency shutoff device for a liquid storage tank according to the present invention with a part thereof omitted.

FIG. 7 is a schematic view showing a sixth embodiment of the emergency shutoff device for a liquid storage tank according to the present invention.

FIG. 8 is a schematic view showing a seventh embodiment of the emergency shutoff device for a liquid storage tank according to the present invention.

FIG. 9 is a schematic view showing another configuration of the sensing mechanism.

[Explanation of symbols]

 1 Emergency Shutoff Device 2 Storage Tank 2a Outlet 3 Supply Pipe 4 Opening / Closing Valve 41 Piston Stop Valve 42 Solenoid Valve 5 Sensing Mechanism 51 Pressure Sensor 52, 53, 54 Sensor 6 Control Panel

Claims (1)

[Claims] 1. A liquid storage tank for storing a liquid such as drinking water, an outlet opening at the bottom of the liquid storage tank, a supply pipe communicating with the outlet and having an opening / closing valve, and an earthquake When a sloshing phenomenon occurs due to the sloshing phenomenon, it consists of a sensing mechanism that senses an abnormal rise in liquid level or abnormal rise in hydraulic pressure due to this sloshing phenomenon. When the liquid level at the peripheral edge of the liquid storage tank rises above the set height, the sensing mechanism senses an abnormal rise in the liquid level or an abnormal rise in hydraulic pressure and closes the on-off valve directly or indirectly. An emergency shutoff device for a liquid storage tank.