Tank shutoff valve

Abstract

To provide a tank shutoff valve that can prevent the outflow of liquid in a tank with a low-cost structure even if the tank is submerged in water due to flooding or the like, the tank floats or moves, or the piping is damaged.SOLUTION: The tank shutoff valve shuts off the flow path of a pipe 11 provided in a tank that stores liquid M. The tank shutoff valve includes: a pressure detection chamber that is partially open to the atmosphere; a water detection unit 20 that detects flooding of the tank based on a change in pressure caused by the inflow of water W into the pressure detection chamber from the outside and the outflow of gas E from the pressure detection chamber to the atmosphere due to the inflow of water W; and a shutoff unit 30 that operates based on the flooding detected by the water detection unit 20 and shuts off the flow path 43 through which liquid M stored in the tank flows.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a tank shutoff valve that prevents the outflow of liquid stored in a tank in the event of a flood. [Background technology]

[0002] Conventionally, coastal areas such as ports have been provided with tanks for storing liquids, such as oil tanks for refueling fishing boats and other vessels (see, for example, Patent Documents 1 and 2). Such tanks are at risk of being damaged by floods such as tsunamis. Therefore, if the piping of a tank installed in a coastal area is damaged by floods such as a tsunami, there is a problem that the liquid stored inside the tank will leak out, and in order to prevent such leakage, shut-off valves or the like are provided on the piping. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-149449 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-227182 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, electric or pneumatic remote shutoff valves have been installed in piping near tanks. However, these electric and pneumatic shutoff valves are explosion-proof, which increases the costs of the valve itself and the electrical and pneumatic equipment, leaving room for improvement in this regard.

[0005] In view of the above circumstances, the present invention aims to provide a tank shutoff valve that can prevent the leakage of liquid from a tank with a low-cost structure even if the tank is submerged in water due to flooding or the like, causing the tank to float or move, or the piping to be damaged. [Means for solving the problem]

[0006] One aspect of the present invention is a tank shut-off valve that shuts off a flow path of a pipe provided in a tank that stores liquid, and is equipped with a pressure detection chamber that is partially open to the atmosphere, a water detection unit that detects water intrusion in the tank based on a change in pressure caused by the inflow of water into the pressure detection chamber from the outside and the outflow of gas from the pressure detection chamber to the atmosphere due to the inflow of water, and a shut-off unit that operates based on the water intrusion detected by the water detection unit and shuts off the flow path through which the liquid stored in the tank flows.

[0007] According to the present invention, flooding of the tank, tank shutoff valve, and its piping can be detected mechanically, rather than electrically, by the water detection unit detecting pressure changes due to the inflow of water and the outflow of gas into the pressure detection chamber. The water detection unit can then activate the shutoff unit to shut off the flow path when it detects flooding. Therefore, in this invention, the tank shutoff valve itself detects the water pressure in the pressure detection chamber when the water level rises due to a flood such as a tsunami, causing water to flow into the pressure detection chamber. This eliminates the need for conventional electrical and pneumatic equipment, and eliminates the need for explosion-proof specifications for this equipment, thereby reducing equipment costs. Thus, this invention can prevent the outflow of liquid from the tank with a low-cost structure, even if the tank, tank shutoff valve, and its piping are submerged due to a flood or other event.

[0008] In addition, in the present invention, it is preferable that the pressure detection chamber has an inlet that is open to the atmosphere and through which water flows in from the outside, and an outlet that is open to the atmosphere and through which gas flows out, which is provided above the inlet.

[0009] According to the present invention, when a flood such as a tsunami occurs, water flows into the pressure detection chamber from the inlet, and the gas in the pressure detection chamber can be released into the atmosphere from the outlet located above the inlet. Therefore, since water accumulates in the pressure detection chamber when a flood occurs, by detecting the pressure change caused by the water flowing into the pressure detection chamber, it is possible to detect flooding of the tank, the tank shut-off valve, and its piping.

[0010] The present invention may also be characterized in that the pressure detection chamber has an inlet that is open to the atmosphere and through which water flows in from the outside, an outlet that is open to the atmosphere and through which gas flows out of the pressure detection chamber, and a diaphragm that separates a first space on the inlet side from a second space on the outlet side, and the diaphragm detects the differential pressure between the first space and the second space.

[0011] According to this invention, when a flood such as a tsunami occurs and the water level rises, water flows into the first space of the pressure detection chamber through the inlet, and gas in the second space of the pressure detection chamber can be discharged to the atmosphere through the outlet located above the inlet. That is, when a flood occurs, the water pressure caused by the water flowing into the first space pushes the diaphragm separating the first space and the second space toward the second space, causing gas in the second space to be discharged through the outlet. The differential pressure between the first space and the second space can be detected from the amount of displacement of the diaphragm at this time, thereby making it possible to detect flooding of the tank, the tank shut-off valve, and its piping.

[0012] In addition, the present invention may be characterized in that the outlet is provided with a check valve that prevents the inflow of gas or liquid from the outside.

[0013] According to the present invention, since the check valve is provided at the outlet, gas in the pressure detection chamber can be reliably discharged to the outside, and gas or liquid from the outside can be prevented from flowing into the pressure detection chamber through the outlet. In other words, since only water flows into the pressure detection chamber from the inlet, it is possible to accurately detect only pressure changes caused by water flowing into the pressure detection chamber.

[0014] The present invention may also be characterized in that it further includes a hood portion formed to cover the water detection portion and preventing water from entering the pressure detection chamber when rain falls from above, while allowing water to enter the pressure detection chamber when water flows in from below.

[0015] According to the present invention, a hood portion is provided to cover the water detection portion, which prevents the pressure detection chamber from being flooded by rainwater falling from above, thereby preventing malfunction. Furthermore, the hood portion allows water flowing in from below to fill the pressure detection chamber without allowing it to flow out. This allows only water to flow into the pressure detection chamber from the inlet, making it possible to accurately detect only pressure changes caused by water flowing into the pressure detection chamber. [Effects of the Invention]

[0016] The tank shut-off valve of the present invention can prevent the liquid in the tank from leaking out with a low-cost structure, even if the tank is submerged in water due to flooding or the like, causing the tank to float or move, or the piping to be damaged. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a side view showing a configuration of a tank equipped with a shutoff valve according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the configuration of a shutoff valve, illustrating a non-shutoff state. [Figure 3] FIG. 2 is a cross-sectional view showing the configuration of a shutoff valve, illustrating a shutoff state. [Figure 4] FIG. 10 is a diagram showing a state before water flows into the pressure detection chamber. [Figure 5] FIG. 10 is a diagram showing a state after water has flowed into the pressure detection chamber. [Figure 6] FIG. 10 is a vertical cross-sectional view showing a shutoff valve provided with a filter and a strainer at the inlet. [Figure 7] FIG. 10 is a vertical cross-sectional view showing a shutoff valve having an air vent hole at the outlet. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tank shutoff valve according to an embodiment of the present invention will now be described with reference to the drawings.

[0019] FIG. 1 is a side view showing the configuration of a tank 10 equipped with a shutoff valve 1 according to an embodiment. The tank shutoff valve (hereinafter, shutoff valve 1) of the embodiment shown in Figure 1 shuts off the flow path of a pipe 11 provided in a tank 10 that stores a liquid M. The shutoff valve 1 is intended for tanks 10 installed in areas (coastal areas, etc.) that may be flooded due to any type of flooding, such as tsunamis, high tides, typhoons, heavy rain, the collapse of dams or levees, or overflows, and is a mechanical type that prevents leakage of the liquid M stored in the tank 10 even if the tank is flooded and the pipe 11 is damaged during a flood. Here, Figure 1 shows the state when a tsunami occurs.

[0020] As shown in FIG. 1, the tank 10 of this embodiment is, for example, a cylindrical oil tank. The tank 10 stores a liquid M, which may be, for example, fuel for ships such as fishing boats, hazardous materials such as gasoline or diesel, or chemicals. The tank 10 is installed on a base 12 provided on the ground. The tank 10 and the base 12 are fixed together using, for example, anchor bolts and nuts. The means for fixing the tank 10 to the base 12 may be reinforced using FRP or the like to integrate the tank 10 and the base 12 to prevent leakage. Alternatively, the tank 10 and the base 12 may not be fixed together.

[0021] A pipe 11 is provided below the tank 10. A liquid M, such as fuel, stored inside the tank 10 flows through the pipe 11. The pipe 11 supplies fuel to a ship or the like. One end of the pipe 11 is connected to the tank 10, and the other end is connected to a nozzle or the like for supplying fuel to the ship or the like. A manual gate valve 13, for example, that blocks the flow path of the pipe 11 is provided midway along the pipe 11. Under normal circumstances, the flow path of the pipe 11 is opened by the gate valve 13. A shutoff valve 1 for the tank 10 (tank shutoff valve) is provided downstream of the gate valve 13. In this embodiment, the shutoff valve 1 is provided midway along the pipe 11, which extends laterally. The shutoff valve 1 automatically shuts off the flow path of the pipe 11 in the event of flooding. The shutoff valve 1 may move together with the tank 10 and the pipe 11 in the unlikely event that the tank 10 is washed away.

[0022] Fig. 2 is a cross-sectional view showing the configuration of shutoff valve 1, illustrating the non-shutoff state. Fig. 3 is a cross-sectional view showing the configuration of shutoff valve 1, illustrating the shutoff state. 2 and 3, the shutoff valve 1 includes a water detection unit 20 that detects flooding of the tank 10, a shutoff unit 30 that shuts off the flow path 43 connected to the pipe 11, and a hood unit 50 formed to cover the water detection unit 20. The shutoff valve 1 is installed in a horizontal position such that the axial direction of the internal flow path 43 is approximately parallel to the pipe 11.

[0023] The shutoff unit 30 is provided in a valve box 40 having a flow path 43 through which the liquid stored in the tank 10 flows. The valve box 40 includes a first housing 41 to which the water detection unit 20 is attached, and a second housing 42 connected to the first housing 41 and to the piping 11. The first housing 41 is located above the second housing 42 when the shutoff valve 1 is installed. The water detection unit 20 is located on the side of the first housing 41.

[0024] 1, the flow path 43 has an inlet portion 431 on the left side of the page, an outlet portion 432 on the right side of the page, and a central communication portion 433 that is provided in the center of the flow path 43 and connects the downstream portion of the inlet portion 431 with the upstream portion of the outlet portion 432. Water W in the pipe 11 that passes through the flow path 43 of the shutoff valve 1 flows from left to right. That is, the water W in the upstream pipe 11 flows in from the inlet portion 431, passes through the central communication portion 433, and flows from the outlet portion 432 to the downstream pipe 11.

[0025] The shutoff unit 30 operates based on flooding detected by the water detection unit 20. The shutoff unit 30 includes a valve element support shaft 31 that moves back and forth in the vertical direction based on flooding detected by the water detection unit 20, a housing portion 32 that houses the valve element support shaft 31, and a valve element 33 that shuts off the flow path 43 by the reciprocating movement of the valve element support shaft 31.

[0026] The valve element 33 is fixed to one end (here, the lower end) of the valve element support shaft 31. That is, the valve element 33 moves up and down as the valve element support shaft 31 reciprocates up and down. The valve element support shaft 31 is equipped with a locking mechanism 34 that operates in conjunction with a coil spring 61 of the water detection unit 20. The valve element support shaft 31 is in a raised position (see FIG. 2) when the locking mechanism 34 is locked, and in a lowered position (see FIG. 3) when the locking mechanism 34 is unlocked. The valve element 33 supported by the valve element support shaft 31 opens the flow path 43 when the valve element support shaft 31 is in the raised position (locking mechanism 34 is in the locked position), and closes the flow path 43 when the valve element support shaft 31 is in the lowered position (locking mechanism 34 is in the unlocked position).

[0027] The valve element 33 is provided in the flow path 43 so as to be able to move up and down. The valve element 33 is provided so as to be able to open and close so as to block a central communication portion 433 of the flow path 43. A valve seat 433a against which the valve element 33 can open and close is provided on the outer peripheral edge of the opening of the central communication portion 433 which interfaces with the inlet portion 431. The outer diameter of the lower end of the valve element 33 is larger than the inner diameter of the opening of the central communication portion 433. The valve element 33 blocks the central communication portion 433 by being pressed against the valve seat 433a from above.

[0028] The locking mechanism 34 includes a biasing member (not shown) that biases the valve element 33 together with the valve element support shaft 31 in a direction pressing the valve element 33 against the valve seat 433a. The biasing member is supported at one end within the accommodation portion 32, and is incorporated so that the other end biases the valve element support shaft 31 and the valve element 33 in a direction pressing the valve element 33 against the valve seat 433a. As shown in FIG. 2, the locking mechanism 34 locks the valve element 33 in a state (open position P1) in which it is separated from the valve seat 433a against the biasing force of the biasing member, and releases the lock by bringing the valve element 33 into contact with the valve seat 433a via the lock operation piece 342 when the coil spring 61 of the water detecting unit 20 is pressed (closed position P2) as shown in FIG.

[0029] The lock mechanism 34 has a lock operating part 341 and a lock operating piece 342 that operates the lock operating part 341. The lock operating piece 342 moves forward and backward in the axial direction X (described below) in response to the detection operation of the water detection unit 20. By operating the lock operating piece 342, the lock operating part 341 raises the valve disc support shaft 31 and the valve disc 33 against the biasing force of the biasing member, locking the valve disc 33 at an open position P1 where the valve disc 33 is separated from the valve seat 433a. By operating the lock operating piece 342, the lock operating part 341 lowers the valve disc support shaft 31 and the valve disc 33 by the biasing force of the biasing member, releasing the lock at a closed position P2 where the valve disc 33 abuts against the valve seat 433a.

[0030] Here, in the water detection unit 20 and the hood unit 50, the diaphragm axis O passes through the center of the diaphragm 24 (described later) in a plan view. The direction parallel to the diaphragm axis O is called the axial direction X. In the axial direction X, the side of the valve disc support shaft 31 is called the inner side X1, and the opposite side is called the outer side X2. Furthermore, the direction perpendicular to the diaphragm axis O when viewed from the axial direction is called the radial direction.

[0031] 1, the hood portion 50 is formed to cover the water detection portion 20, and prevents water from falling from above from entering the pressure detection chamber 21, while allowing water W to enter the pressure detection chamber 21 when it flows in from the inlet 22 below. The hood portion 50 is divided into two portions in the axial direction X. The pair of divided hood portions 50 are fixed together while sandwiching the outer peripheral edge 24a of the diaphragm 24 (described later) over the entire circumference.

[0032] The hood portion 50 is formed in a substantially cylindrical shape coaxial with the diaphragm axis O. The hood portion 50 includes a first hood body 51 that defines the pressure detection chamber 21 that houses the water detection unit 20, and a second hood body 52 that houses the coil spring 61. The first hood body 51 is fixed to the first housing 41. The second hood body 52 is provided on the opposite side (outside X2) of the first housing 41 across the first hood body 51. The first hood body 51 includes a central cylinder 51A that is located in the center of the axial direction X and supports the diaphragm 24, an inner plate 51B that is located on the first housing 41 side of the central cylinder 51A, and an outer plate 51C that is located on the second hood body 52 side of the central cylinder 51A. In the hood portion 50, the central cylinder 51A has the largest inner diameter.

[0033] The second hood body 52 is cylindrical and arranged coaxially with the diaphragm axis O. The inner end of the second hood body 52 is an open end and communicates with the inside of the first hood body 51 (pressure detection chamber 21). The outer end of the second hood body 52 is closed by a lid body 53. A coil spring 61 arranged coaxially with the diaphragm axis O is housed inside the second hood body 52. ​​The inner diameter of the second hood body 52 is larger than the outer diameter of the coil spring 61. Within the second hood body 52, a reaction wall 54 that supports one end 61a of the coil spring 61 is provided on the inside X1 of the lid body 53.

[0034] Fig. 4 is a diagram showing a state before water W flows into the pressure detection chamber 21. Fig. 5 is a diagram showing a state after water W flows into the pressure detection chamber 21. 4 and 5, the water detection unit 20 includes a pressure detection chamber 21 that is partially open to the atmosphere. The water detection unit 20 detects flooding of the tank 10 based on a change in pressure caused by the inflow of water W from the outside into the pressure detection chamber 21 and the outflow of gas E from the pressure detection chamber 21 to the atmosphere as the water W inflows.

[0035] The pressure detection chamber 21 has an inlet 22 and an outlet 23. The inlet 22 is provided below the pressure detection chamber 21 and is open to the atmosphere, through which water W flows in from the outside. The inlet 22 is located on one of the left and right sides of the hood portion 50 when viewed from the axial direction X (the far side of the paper in Figures 3, 4, and 5), and opens downward. The inlet 22 is formed in an umbrella shape that increases in diameter as it extends downward. By making the inlet 22 umbrella-shaped in this way, the inflow of water W is stabilized and malfunctions in the detection of water W can be prevented. The outlet 23 is provided above the inlet 22 and is open to the atmosphere, through which gas E flows out of the pressure detection chamber 21. The outlet 23 opens upward. It is desirable to provide multiple inlets 22 so that water W can flow in against tsunamis coming from any direction, i.e., so that the inflow of water W is not restricted by valves or nearby structures or vortices.

[0036] The pressure detection chamber 21 has a diaphragm 24 that separates a first space 21A on the inlet 22 side from a second space 21B on the outlet 23 side in a horizontal direction (axial direction X) perpendicular to the up-down direction. The first space 21A is located on the first housing 41 side. The second space 21B is located on the opposite side of the diaphragm 24 from the first space 21A. The inlet 22 communicates with the first space 21A but does not communicate with the second space 21B. The outlet 23 communicates with the second space 21B but does not communicate with the first space 21A. By providing the outlet 23, when water W enters the first space 21A from the inlet 22, gas E can be released upward to prevent air from pooling in the first space 21A.

[0037] The diaphragm 24 is disposed within the pressure detection chamber 21 so as to divide the pressure detection chamber 21 laterally, and detects the differential pressure between the first space 21A and the second space 21B. The diaphragm 24 is fixed in place with its outer peripheral edge 24a sandwiched between a pair of divided hood portions (described below). The diaphragm 24 is formed from an elastic member, and divides the first space 21A and the second space 21B in a liquid-tight manner.

[0038] The central portion of the diaphragm 24 in a plan view is sandwiched and supported by a pair of support plates 62A, 62B. The first support plate 62A supports the diaphragm 24 from the first space 21A side. The second support plate 62B supports the diaphragm 24 from the second space 21B side. One end 342a of a lock operation piece 342 extending coaxially with the diaphragm axis O is fixed to the first support plate 62A. The lock operation piece 342 liquid-tightly penetrates the hood portion 50 and the pressure detection chamber 21, and the other end 342b is connected to the lock operation portion 341 inside the first housing 41 (see FIG. 2). The diaphragm 24 is movable back and forth in the axial direction X by the action of water W flowing into the first space 21A and the spring force of the coil spring 61.

[0039] The outer diameter of the second support plate 62B is smaller than the inner diameter of the central cylinder 51A of the hood portion 50. The other end 61b of the coil spring 61 presses against the outer surface 62a of the second support plate 62B from the outer side X2. That is, the diaphragm 24 supported by the second support plate 62B is maintained in a state in which it is biased toward the inner side X1 by the biasing force of the coil spring 61. When water W flows into the first space 21A, the water pressure causes the diaphragm 24 to displace toward the outer side X2 against the biasing force of the coil spring 61. When the water W flows out of the first space 21A, the water pressure in the first space 21A decreases, and the diaphragm 24 is displaced toward the outer side X2 against the biasing force of the coil spring 61.

[0040] The water detection unit 20 detects the inflow of water W into the first space 21A of the pressure detection chamber 21 by detecting the pressure difference between the first space 21A and the second space 21B. For example, as shown in FIG. 5, the water detection unit 20 detects the second head h2 after water W has flowed into the first space 21A (when a tsunami has occurred), and detects a water pressure change (pressure change) from the head difference Δh (= h2 - h1) between this and the first head h1 before water W flowed into the first space 21A (when no tsunami has occurred). When this water pressure change is detected, the first space 21A is filled with water W, and the resulting water pressure displaces the diaphragm 24 outward X2 against the bias of the coil spring 61. For example, the water pressure at which the shutoff valve 1 operates is set to be greater than 0 kPa and equal to or less than 2.0 kPa.

[0041] FIG. 6 is a vertical cross-sectional view showing the shutoff valve 1 in which a filter 25 and a strainer 26 are provided at the inlet 22. As shown in FIG. As shown in Fig. 6, the inlet 22 has a mesh filter 25 and a cylindrical strainer 26 with slits or small holes that cover the outer periphery of the filter 25. The filter 25 is conical. By providing the filter 25 and the strainer 26 at the inlet 22, it is possible to prevent drifting debris contained in the tsunami water W, such as wood chips, leaves, mud, and pebbles, from entering the first space 21A of the pressure detection chamber 21 while allowing the water W to pass through. This prevents the inlet 22 from becoming clogged with debris, leaves sticking to it, or the like, preventing the water W from flowing into the pressure detection chamber 21.

[0042] FIG. 7 is a vertical cross-sectional view showing the shutoff valve 1 in which an air vent hole 55 is provided at the outlet 23. As shown in FIG. As shown in Fig. 7, outlet 23 is provided with air vent hole 55 (check valve) that prevents the inflow of gas or liquid from the outside. Here, in Fig. 7, outlet 23 is provided in second hood body 52. ​​Air vent hole 55 has a shape that extends upward from outlet 23, turns back at U-shaped turning portion 55a, and then extends further downward. Because tip opening 55b of air vent hole 55 faces downward, it is possible to prevent water during rainfall from flowing into second space 21B through air vent hole 55.

[0043] The operation of the shutoff valve 1 having the above-described configuration will now be described. 5, when water W flows into the first space 21A of the pressure detection chamber 21 inside the hood portion 50 through the inlet 22 in the event of a flood, the diaphragm 24 is displaced toward the second space 21B (outer side X2) by the pressure of the water W. At this time, the pressure of the water W flowing into the first space 21A becomes greater than the spring force (biasing force) of the coil spring 61. Therefore, the diaphragm 24 is displaced toward the outer side X2 against the biasing force of the coil spring 61. At this time, the gas E in the second space 21B flows out through the outlet 23 to the outside.

[0044] When the diaphragm 24 moves outward X2 in the axial direction X, the lock operation piece 342 of the lock mechanism 34, which is fixed to the first support plate 62A that supports the diaphragm 24, also moves outward X2. Then, the movement of the lock operation piece 342 releases the lock of the lock operating portion 341 of the lock mechanism 34.

[0045] Next, when the locking mechanism 34 is unlocked, as shown in Figure 3, the valve element support shaft 31 and valve element 33 are lowered by the biasing force of a biasing member (not shown), and the valve element 33 is pressed against the valve seat 433a formed in the central communication part 433 of the flow path 43. In other words, the valve element 33 moves from the open position P1 (see Figure 2) to the closed position P2, and even if a power outage occurs during a flood such as a tsunami, the water W caused by the tsunami can be detected and the flow path 43 in the cutoff part 30 can be reliably shut off.

[0046] Thereafter, the manual gate valve 13 (see FIG. 1) is closed to prevent the liquid M, such as fuel, from flowing out of the tank 10. The shutoff valve 1 is removed from the piping 11 and replaced with a new one. The shutoff valve 1 may be reused by replacing the replacement parts.

[0047] Next, the operation of the shutoff valve 1 will be described in detail with reference to the drawings. The shutoff valve 1 according to this embodiment shuts off a flow path of a pipe 11 provided in a tank 10 that stores a liquid M. The shutoff valve includes a pressure detection chamber 21 that is partially open to the atmosphere, and is equipped with a water detection unit 29 that detects flooding of the tank 10 based on a change in pressure caused by the inflow of water W into the pressure detection chamber 21 from the outside and the outflow of gas E from the pressure detection chamber 21 to the atmosphere due to the inflow of water W, and a shutoff unit 30 that operates based on the flooding detected by the water detection unit 29 and shuts off a flow path 43 through which the liquid M stored in the tank 10 flows.

[0048] According to the shutoff valve 1 of this embodiment, flooding of the tank 10 can be detected mechanically, rather than electrically, by the water detection unit 20 detecting pressure changes due to the inflow of water W and the outflow of gas E into the pressure detection chamber 21. The detection of flooding by the water detection unit 20 can then activate the shutoff unit 30 to shut off the flow path 43. Therefore, in this embodiment, the shutoff valve 1 itself detects the water pressure in the pressure detection chamber 21 when the water level rises due to a flood such as a tsunami, causing water W to flow into the pressure detection chamber 21. This eliminates the need for conventional electrical and pneumatic equipment, and eliminates the need for explosion-proofing of these equipment, thereby reducing equipment costs. Thus, in this embodiment, even if the tank 10, the shutoff valve 1, and their piping 11 are submerged in water due to a flood or other event, the outflow of liquid M from the tank 10 can be prevented with a low-cost structure.

[0049] In addition, in this embodiment, the pressure detection chamber 21 has an inlet 22 that is open to the atmosphere and through which water W flows in from the outside, and an outlet 23 that is located above the inlet 22, is open to the atmosphere, and through which gas E flows out. Therefore, when a flood such as a tsunami occurs, water W flows into the pressure detection chamber 21 from the inlet 22, and the gas E in the pressure detection chamber 21 can be discharged into the atmosphere from the outlet 23 located above the inlet 22. Therefore, since water accumulates in the pressure detection chamber 21 when a flood occurs, by detecting the pressure change caused by the water W flowing into the pressure detection chamber 21, it is possible to detect flooding of the tank 10, the shutoff valve 1 and its piping 11.

[0050] In addition, this embodiment includes a diaphragm 24 that separates the first space 21A on the inlet 22 side from the second space 21B on the outlet 23 side. The diaphragm 24 detects the differential pressure between the first space 21A and the second space 21B. Therefore, when a flood such as a tsunami occurs and the water level rises, water W flows into first space 21A of pressure detection chamber 21 from inlet 22, and gas E in second space 21B of pressure detection chamber 21 can be discharged to the atmosphere from outlet 23 located above inlet 22. That is, when flooding occurs, the water pressure caused by the water W flowing into first space 21A presses diaphragm 24 separating first space 21A and second space 21B toward second space 21B, causing gas E in second space 21B to be discharged from outlet 23. The differential pressure between first space 21A and second space 21B can be detected from the amount of displacement of diaphragm 24 at this time, and thereby flooding of shutoff valve 1 can be detected.

[0051] In this embodiment, the outlet 23 is provided with an air vent hole 55 that prevents the inflow of gas or liquid from the outside. In this embodiment, the air vent hole 55 is provided in the outlet 23, so that the gas E in the pressure detection chamber 21 can be reliably discharged to the outside, and gas or liquid from the outside can be prevented from flowing into the pressure detection chamber 21 through the outlet 23. In other words, since only water W flows into the pressure detection chamber 21 from the inlet 22, only pressure changes due to water flowing into the pressure detection chamber 21 can be accurately detected.

[0052] In addition, this embodiment further includes a hood portion 50 that is formed to cover the water detection portion 20 and prevents water from entering the pressure detection chamber 21 when rain falls from above, while allowing water W to enter the pressure detection chamber 21 when water flows in from below. In this way, the hood portion 50 that covers the water detection unit 20 is provided, so that it is possible to prevent water from falling from above from flooding the pressure detection chamber 21, thereby preventing malfunction. Furthermore, by providing the hood portion 50, it is possible to fill the pressure detection chamber 21 with water W that flows in from below without allowing it to flow out. As a result, only water flows into the pressure detection chamber 21 from the inlet 22, so that it is possible to accurately detect only pressure changes caused by water flowing into the pressure detection chamber 21.

[0053] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents.

[0054] For example, in this embodiment, the water detection unit 20 uses the differential pressure between the first space 21A and the second space 21B to detect water, but this is just one example and other detection methods can be used. For example, it is also possible to use a water detection method that detects the spring force of the coil spring 61, which changes depending on the pressing force of the diaphragm 24. For example, as described above, the pressure difference between the water pressure and the spring force of the coil spring or the like may be set to a range greater than 0 kPa and less than or equal to 2.0 kPa. In other words, if the spring force is 1.0 kPa, the diaphragm 24 will be pressed toward the second space 21B when the water pressure of the water W flowing into the first space 21A exceeds 1.0 kPa.

[0055] Furthermore, in this embodiment, the inlet 22 is disposed on one of the left and right sides of the hood portion 50 when viewed from the axial direction X, but it may be disposed on both the left and right sides. That is, the number of inlet 22 is not limited to one, and multiple inlet 22 may be provided. Furthermore, the inlet 22 is not limited to opening downward, and may open sideways.

[0056] Furthermore, in this embodiment, the air vent hole 55 having the folded portion 55a bent downward is used as the check valve provided at the outlet 23, but the configuration is not limited to this. As another configuration of the check valve, for example, a check valve configured to be sealed at the tip of a pipe extending vertically upward from the outlet 23 with a material that can be ruptured by the pressure of the gas E pushed out from the second space 21B can be used. [Explanation of symbols]

[0057] 1 shutoff valve (tank shutoff valve), 10 tank, 11 piping, 20 water detection part, 21 pressure detection chamber, 21A first space, 21B second space, 22 inlet, 23 outlet, 24 diaphragm, 25 filter, 26 strainer, 30 shutoff part, 31 valve body support shaft, 33 valve body, 34 lock mechanism, 40 valve body, 43 flow path, 50 hood part, 55 air vent hole (check valve), 61 coil spring, 5 guide part, 433 central connecting part, 433a valve seat, E gas, M liquid, O diaphragm axis, X axial direction, W water

Claims

1. A tank shutoff valve that shuts off a flow path of a pipe provided in a tank that stores a liquid, a water detection unit that includes a pressure detection chamber that is partially open to the atmosphere and that detects flooding of the tank based on a change in pressure caused by an inflow of water into the pressure detection chamber from the outside and an outflow of gas from the pressure detection chamber to the atmosphere due to the inflow of water; a blocking unit that operates based on the flooding detected by the water detection unit and blocks the flow path through which the liquid stored in the tank flows; Equipped with Tank shutoff valve.

2. The pressure detection chamber is an inlet that is open to the atmosphere and through which water flows in from the outside; An outlet provided above the inlet, open to the atmosphere, and through which the gas flows out.

2. The tank shut-off valve according to claim 1.

3. The pressure detection chamber is an inlet that is open to the atmosphere and through which water flows in from the outside; an outlet that is open to the atmosphere and through which gas flows out of the pressure detection chamber; a diaphragm separating a first space on the inlet side from a second space on the outlet side, The diaphragm detects a differential pressure between the first space and the second space.

2. The tank shut-off valve according to claim 1.

4. The outlet is provided with a check valve to prevent the inflow of gas or liquid from the outside.

4. The tank shutoff valve according to claim 2 or 3.

5. a hood portion formed to cover the water detection portion and preventing water from entering the pressure detection chamber when rain falls from above, and allowing water to enter the pressure detection chamber when water flows in from below; 2. The tank shut-off valve according to claim 1.

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