JPH1073171A - Emergency valve for water tank - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the number of valves used to increase reliability, to reduce the installation space, and to simplify the manufacture by omitting the use of piping material having a complicated structure. A first inflow port (P1) communicating with an upstream main pipe (1A) of a water distribution main pipe (1), a first outflow port (P2) communicating with a downstream main pipe (1B) of the water distribution main pipe (1), and a communication with an inlet (2A) of a water storage tank (2). A valve body 1 which forms a second outflow port P3, a second inflow port P4 communicating with the outlet 2B of the water storage tank 2 and a pilot port P5 communicating with the water distribution main pipe 1, and is inserted therein.
Urging means 15 for urging 4 in a direction against the pilot pressure
A cylindrical valve box 13 provided with a pressure chamber 16
The valve body 14 is moved to the other end side of the valve box 13 against the urging of the urging means 15 by the pilot pressure of the above, and the water tank 2 is made to function as a part of the water pipe. By the urging of the urging means 15, the valve body 14 is moved to one end side of the valve box 13 to prevent inflow of sewage into the water storage tank 2, and drinking water for emergency water supply is stored in the water storage tank 2. In addition to securing water, the water distribution main pipe 1 is required to have sufficient water flow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water storage tank which is installed in a pipeline between a water distribution main pipe of a water supply facility and an earthquake-resistant water storage tank, and is operated when an abnormal situation such as breakage of the water distribution main pipe occurs. The present invention relates to an emergency valve for a water storage tank that prevents inflow of sewage into a water tank and ensures water flow through a water distribution main pipe.

[0002]

2. Description of the Related Art Conventionally, for example, an inflow which connects an upstream main pipe 1A of a water distribution main pipe 1 and an inlet 2A of an earthquake-resistant water storage tank 2 (hereinafter simply referred to as a water storage tank 2) in a water supply facility as shown in FIG. An inflow valve 4 interposed in the pipe 3, an outflow valve 6 interposed in an outflow pipe 5 for communicating the outlet 2 </ b> B of the water storage tank 2 with the downstream main pipe 1 </ b> B of the water distribution main pipe 1, and an inflow valve 4 in the inflow pipe 3. Upstream position and downstream position of the outflow valve 6 in the outflow pipe 5,
That is, the bypass valve 8 is connected to the bypass pipe 7 that connects the primary side 3A of the inflow pipe 3 and the secondary side 5B of the outflow pipe 5.
An emergency valve for a water tank using a plurality of valves 4, 6, 8 is known. In the drawings, V1, V2, and V3 indicate water control valves.

In the conventional emergency valve for a water storage tank having the above-described structure, the bypass valve 8 and the water control valve V are normally used as shown in FIG.
1 is closed, the inflow valve 4 and the outflow valve 6 and the water control valve V2,
V3 is opened. For this reason, as shown by the arrow in FIG. 2 and is stored. Further, the water that has flowed out of the water storage tank 2 flows down along the route of the primary side 5A of the outflow pipe 5 → the outflow valve 6 → the secondary side 5B of the outflow pipe 5 → the downstream main pipe 1B of the water distribution main pipe 1. In this state, the water storage tank 2 functions as a part of the water pipe.

[0004] For example, when an abnormal situation such as breakage of the water distribution main 1 occurs due to an earthquake or the like and the water pressure of the water distribution main 1 drops below a set value, the water pressure is detected and as shown in FIG. The inflow valve 4 and the outflow valve 6 are closed, and the bypass valve 8 is opened. For this reason, as shown by the arrow in FIG. 8, water flows from the upstream main pipe 1A of the water distribution main pipe 1 → the primary side 3A of the inflow pipe 3 → the bypass pipe 7 → the secondary side 5B of the outflow pipe 5 → the water distribution main pipe 1 Flows down the path of the downstream main pipe 1B. Thereby, the inflow of sewage into the water storage tank 2 is prevented, drinking water for emergency water supply is secured in the water storage tank 2, and the water supply main pipe 1 is connected to the water distribution main pipe 1 by securing water flow. A usable state such as a fire hydrant (not shown) can be obtained.

[0005] However, the conventional emergency valve for a water storage tank requires three valves of the inflow valve 4, the outflow valve 6, and the bypass valve 8, and the number of used valves increases, and the probability of malfunctioning increases accordingly. For this reason, if at least one of the three valves malfunctions at the time of occurrence of an abnormal situation, even if the inflow of sewage into the water storage tank 2 can be prevented, the inflow of the water distribution main pipe 1 is not ensured, or Even if the water distribution of the water distribution main pipe 1 can be ensured, inconvenience that the inflow of sewage into the water storage tank 2 cannot be prevented occurs. In addition, a large installation space is required.

Therefore, there has been proposed an emergency valve for a water tank in which the above-mentioned disadvantages have been solved by reducing the number of valves used and reducing the probability of malfunction of the valve. As shown in FIGS. 9 and 10, this type of emergency valve for a water tank includes one emergency shutoff type butterfly valve 9. The butterfly valve 9 is interposed between the distribution pipe 10A on the water distribution main pipe side and the distribution pipe 10B on the water storage tank side. Distribution pipe 10 on the water distribution main side
A is connected to the primary side 3A of the inflow pipe 3 and the secondary side 5B of the outflow pipe 5 via the T-shaped pipe 11, and the branch pipe 10B on the water storage tank side is connected to the secondary side of the inflow pipe 3 via the T-shaped pipe 12. The side 3B and the primary side 5A of the outflow pipe 5 are connected. In addition, the distribution pipe 1 on the water distribution main side
0A is divided into an upper passage 5B1 and a lower passage 3A1, as shown in FIG.
B is partitioned into an upper passage 5A1 and a lower passage 3B1. And the primary side 3 of the inflow pipe 3 is provided in the T-shaped pipe 11.
A and lower passage 3A in distribution pipe 10A on the water distribution main side
1 is provided, and a partition wall 11A is provided for communicating the secondary side 5B of the outflow pipe 5 with the upper passage 5B1 of the distribution pipe 10A on the water distribution main pipe side.
Partition wall which makes the secondary side 3B communicate with the lower passage 3B1 of the water splitter pipe 10B and the primary side 5A of the outflow pipe 5 and the upper passage 5A1 of the water splitter pipe 10B. 12A is provided. In the figure, V
Reference numeral 1 denotes a water control valve.

With such a configuration, the butterfly valve 9 is normally opened as shown in FIGS.
The water control valve V1 is closed. Therefore, as shown by arrows in FIGS. 9 and 10, water is supplied to the upstream main pipe 1 </ b> A of the water distribution main pipe 1.
→ Primary side 3A of the inflow pipe 3 → T-shaped pipe 11 → Lower passage 3A1 under the water distribution main pipe 10A → Butterfly valve 9 → Lower passage 3B1 under the water distribution pipe 10B → Inflow pipe 3 Flows into the water storage tank 2 through the path of the secondary side 3B. The water that has flowed out of the water storage tank 2 is discharged from the primary side 5A of the outflow pipe 5 to T.
Passage 12A → Upper passage 5A1 of branch pipe 10B on the reservoir side
→ Butterfly valve 9 → Upper passage 5B1 of distribution pipe 10A on the water distribution main side → T-shaped pipe 11 → Secondary side 5B of outflow pipe 5 → Downstream main pipe 1B of water distribution main pipe 1 flows down. In this state, the water storage tank 2 functions as a part of the water pipe.

For example, when an abnormal situation such as breakage of the water distribution main 1 occurs due to an earthquake or the like and the water pressure of the water distribution main 1 falls below a set value, this water pressure is detected and the water pressure is detected as shown in FIGS. As shown, the butterfly valve 9 closes. For this reason, as shown by arrows in FIGS. 11 and 12, the water flows from the upstream main pipe 1A of the water distribution main pipe 1 → the primary side 3A of the inflow pipe 3 → the T-shaped pipe 11 → the distribution pipe 10A on the water distribution main pipe side. Lower passage 3A1
→ Before the butterfly valve 9 → Upper passage 5B1 of the distribution pipe 10A on the water distribution main side → T-shaped pipe 11 → Secondary side 5B of the outflow pipe 5
→ It flows down the route of the main pipe 1B on the downstream side of the water distribution main pipe 1. Thereby, the inflow of sewage into the water storage tank 2 is prevented, drinking water for emergency water supply is secured in the water storage tank 2, and the water supply main pipe 1 is connected to the water distribution main pipe 1 by securing water flow. A usable state such as a fire hydrant (not shown) can be obtained.

[0009] However, the above-mentioned emergency valve for a water tank devised to reduce the number of used valves is provided with a distribution pipe 10A on a water distribution main side divided into an upper passage 5B1 and a lower passage 3A1.
And the water dividing tank 10B on the water storage tank side divided into the upper passage 5A1 and the lower passage 3B1, and the lower passage 3A1 of the primary side 3A of the inflow pipe 3 and the distribution main pipe 10A on the water distribution main side. And a T-shaped pipe 11 provided with a partition wall 11A for communicating the secondary side 5B of the outflow pipe 5 and the upper passage 5B1 of the distribution pipe 10A on the water distribution main side, and the secondary side 3B of the inflow pipe 3 and the water storage tank. Lower passage 3B in the side branch pipe 10B
1 and a T-shaped pipe 12 provided with a partition wall 12A for communicating the primary side 5A of the outflow pipe 5 with the upper passage 5A1 of the water splitting pipe 10B on the water storage tank side. In addition, the distribution pipe 10A on the water distribution main pipe side, the distribution pipe 10B on the water storage tank side, the T-shaped pipe 11 and the T-shaped pipe 12 have complicated structures, and therefore are difficult to manufacture.

[0010]

That is, the conventional emergency valve for a water tank requires a large number of valves to be used, causes inconvenience in that water cannot be supplied to a water distribution main pipe when an abnormal situation occurs, Since the probability of occurrence of inconveniences that cannot prevent inflow of sewage is high, it is inferior in reliability and has the drawback that a large installation space is required. Since complicated piping materials such as branch pipes and T-shaped pipes have to be used, they have a drawback that they are difficult to manufacture.

Accordingly, the present invention reduces the number of valves used, reduces the probability of occurrence of the above-described inconvenience in the event of an abnormal situation, improves reliability, reduces installation space, and has a complicated structure. It is an object of the present invention to provide an emergency valve for a water storage tank that can be easily manufactured by omitting use of piping materials such as a simple branch pipe and a T-shaped pipe.

[0012]

In order to achieve the above object, an emergency valve for a water tank according to the first aspect of the present invention has a cylindrical valve box and an axially movable valve inside the valve box. A valve body freely inserted therein, and a peripheral wall portion of the valve box has a first inflow port communicating with an upstream main pipe of the water distribution main pipe at a position spaced apart in the axial direction thereof, and a water distribution main pipe. A first outflow port communicating with the downstream main pipe is formed, and is separated from the first inflow port and the first outflow port in a circumferential direction of the valve box, respectively, and at positions separated from both ends in the axial direction. A second outflow port and a second inflow port are respectively formed to communicate with the inlet and the outlet of the water storage tank, and the valve box is provided with a water pressure of the water distribution main pipe as a pilot pressure, and a shaft is inserted into the valve body. And a pilot port for applying a moving force to one side in the direction. An urging means for urging the valve body toward the other side in the axial direction against the pilot pressure is provided, and in a region where the water pressure of the water distribution main pipe exceeds a set value, the urging means is actuated by the pilot pressure. The valve main body is moved to one side in the axial direction of the valve box against the force of the valve body to communicate the first inflow port with the second outflow port, the first outflow port with the second inflow port, and the water distribution main pipe In a region where the water pressure is equal to or lower than a set value, the valve body is moved toward the other axial side of the valve box by the urging of the urging means to connect the first inflow port and the first outflow port. It is characterized by being.

The emergency valve for a water tank according to the second aspect of the present invention includes a cylindrical valve box, and a valve body that is axially movably mounted inside the valve box. A first inflow port communicating with the upstream main pipe of the water distribution main pipe and a first outflow port communicating with the downstream main pipe of the water distribution main pipe are formed in the peripheral wall portion of the valve box at an axial interval. A second outflow port is formed at a position away from the first inflow port in the circumferential direction of the valve box and away from one end side in the axial direction, leading to the inlet of the water storage tank;
A second inflow port communicating with an outlet of the water storage tank is formed at a position away from the first outflow port in a circumferential direction of the valve box, and at a position away from the other end in the axial direction. A pilot port is provided at one end to introduce the water pressure of the water distribution main pipe as pilot pressure into the inside and load the valve body, and the other end of the valve box in the axial direction opposes the pilot pressure. An urging means for urging the main body is provided, and in a region where the water pressure of the water distribution main pipe exceeds a set value, the valve body is moved in the axial direction of the valve box against the urging of the urging means by the pilot pressure. Moved to the other end side, the first inflow port and the second outflow port, and the first outflow port and the second
An inflow port is communicated, and in a region where the water pressure of the water distribution main pipe is equal to or lower than a set value, the valve body is moved to one axial end side of the valve box by the urging of the urging means, and the first inflow port and the first inflow port are moved to the first inflow port. It is characterized in that it is configured to communicate with the outflow port.

According to the first and second aspects of the present invention, a single valve including a valve box and a valve body which is axially movably mounted inside the valve box is used. In addition, the use of piping materials such as diverting pipes and T-shaped pipes with complicated structures is omitted, and it is interposed between the water distribution main pipe and the water storage tank, and it operates urgently when an abnormal situation such as breakage of the water distribution main pipe occurs As a result, it is possible to prevent inflow of sewage into the water storage tank and to secure water flow through the water distribution main pipe.

[0015]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a partial cross section of one embodiment of the present invention in a normal state. The same or corresponding parts as in the conventional example are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 1, an emergency valve V for a water tank has one cylindrical valve box 13 and this valve box 1.
3 and a valve body 14 which is movably mounted in the axial direction. The valve body 14 is constituted by a spool valve,
It has a large-diameter piston portion 14A at one end in the axial direction, a large-diameter first valve portion 14B at the other axial end, and a large-diameter second valve portion 14C at a substantially central portion in the axial direction. These are integrally formed via a pair of small diameter portions 14D, 14D, and have an outer diameter that can be water-sealed between the outer peripheral surface and the inner peripheral surface of the valve box 13.

Inside the valve box 13, an annular first stopper 13A, an annular second stopper 13B and an annular third stopper 13C are provided, and a large-diameter piston portion 14 is provided.
A is located in the pressure chamber 16 at one axial end of the first annular stopper 13A, and the large-diameter first valve body 14B is located within the biasing chamber 17 at the other axial end. The second valve body portion 14C having a diameter is located in the inflow chamber 18 between the first annular stopper 13A and the second annular stopper 13B. An outflow chamber 19 is formed between the annular second stopper 13B and the annular third stopper 13C.

On the other hand, the valve box 13 has a first inflow port P1 penetrating the peripheral wall thereof and leading to the inflow chamber 18;
A first outflow port P2 communicating with the pressure chamber 16 is formed through a peripheral wall 180 ° in a circumferential direction from a position where these ports P1 and P2 are formed.
A second outflow port P3 leading to a position biased toward the first stopper 13A side and a second inflow port P4 leading to a position biased toward the third stopper 13C side in the urging chamber 17. A pilot port P5 penetrating through one end of the valve box 13 and communicating with the pressure chamber 16 is provided.
A biasing means 15 composed of a spring is inserted into the biasing chamber 17, and constantly biases the valve body 14 composed of a spool valve toward one axial end.

The water tank emergency valve V is provided between the water distribution main pipe 1 and the water tank 2 in the water supply facility. That is, the upstream main pipe 1A of the water distribution main pipe 1 is connected to the first inflow port P1 via the primary side 3A of the inflow pipe 3, and the downstream main pipe 1B of the water distribution main pipe 1 is connected to the secondary side 5B of the outflow pipe 5. , The inlet 2A of the water storage tank 2 is connected to the second outflow port P3 via the secondary side 3B of the inflow pipe 3, and the outlet 2B of the water storage tank 2 is connected to the outflow pipe 5 Is connected to the second inflow port P4 via the primary side 5A. An upstream main pipe 1A of the water distribution main pipe 1 is connected to a pilot port P5 via a pilot pipe 20. In the figure, V1 indicates a water control valve.

With such a configuration, the water pressure of the water distribution main pipe 1 exceeds the set value in normal times, and this water pressure is introduced into the pressure chamber 16 from the pilot port P5 as the pilot pressure. A load is applied to the large-diameter piston portion 14A, and the valve body 14 is
To the other end in the axial direction. Thereby, as shown in FIG. 1, the first inflow port P <b> 1 is formed via the portions of the inflow chamber 18 and the pressure chamber 16 biased toward the first stopper 13 </ b> A.
And the second outflow port P3 communicate with each other, and the urging chamber 17
Of the first outflow port P2 and the second inflow port P through the portion deviated toward the third stopper 13C side and the outflow chamber 19 in FIG.
4 communicates. Therefore, as shown by the arrow in FIG. 1, the water flows from the upstream main pipe 1 </ b> A of the water distribution main pipe 1 to the primary side 3 of the inflow pipe 3.
A → first inflow port P1 → inflow chamber 18 → portion of pressure chamber 16 biased toward first stopper 13A → second outflow port P3 → flows into water storage tank 2 via secondary side 3B of inflow pipe 3 It will be stored. Further, the water flowing out of the water storage tank 2 is discharged from the primary side 5A of the outflow pipe 5 → the second inflow port P4 → a part of the biasing chamber 17 biased toward the third stopper 13C → the outflow chamber 1
9 → the first outflow port P2 → the secondary side 5B of the outflow pipe 5 → the downstream main pipe 1B of the water distribution main pipe 1 flows down. In this state, the water storage tank 2 functions as a part of the water pipe.

For example, when an abnormal situation such as breakage of the water distribution main pipe 1 occurs due to an earthquake or the like, the water pressure of the water distribution main pipe 1 falls below a set value, and the pilot pressure of the pressure chamber 16 becomes low, the urging means 15 is turned on. As shown in FIG. 2, the second valve body portion 14C comes into contact with the first stopper 13A and the first
The valve body 14 is moved to one axial end of the valve box 13 until the valve body 14B comes into contact with the third stopper 13C. Thereby, the first inflow port P1 and the first outflow port P2 communicate via the inflow chamber 18 and the outflow chamber 19 in a short-circuited manner. For this reason, as shown by the arrow in FIG. 2, the water flows from the upstream main pipe 1A of the water distribution main pipe 1 → the primary side 3A of the inflow pipe 3 → the first inflow port P1 → the inflow chamber 18 → the outflow chamber 19 → the first outflow. It flows down along the route of port P2 → secondary side 5B of outflow pipe 5 → downstream main pipe 1B of water distribution main pipe 1. Therefore, the inflow of sewage into the water storage tank 2 is prevented, drinking water for emergency water supply is secured in the water storage tank 2, and the fire hydrant connected to the water distribution main pipe 1 by securing the water distribution of the water distribution main pipe 1. A usable state such as (not shown) can be obtained.

As described above, the water tank emergency valve V according to the present invention reduces the number of valves used to one to prevent the water distribution of the water distribution main pipe 1 from being ensured in the event of an abnormal situation.
Reduces the probability of inconvenience that cannot prevent the inflow of sewage into the facility, increases reliability,
The installation space can be reduced, and restrictions on space can be eased. Moreover, the distribution pipe 10A on the water distribution main pipe 1 side and the distribution pipe 1 on the water storage tank 2 side shown in the conventional example of FIGS.
By omitting the use of piping materials having complicated structures such as OB, T-shaped pipe 11 and T-shaped pipe 12, the water distribution main pipe 1 may be damaged by being interposed between the water distribution main pipe 1 and the water storage tank 2. When the abnormal situation occurs, it can be operated urgently to prevent the inflow of sewage into the water storage tank 2 and to secure the water flow through the water distribution main pipe 1, so that the production is simple.

In the above embodiment, the urging means 15
3, a rod 21 projecting outward from the other axial end of the valve box 13 to the first valve main body portion 14B of the valve main body 14, as shown in FIG.
1 is connected to a long hole 22a by a pin at its upper end, and a lever 22 is rotatably pin-connected at its tip to the valve box 13, and a counterweight 23 attached to the lever 22 so as to be movable in the axial direction. The urging means 15 may be constituted by. In FIG. 3, the same or corresponding parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the above embodiment, the valve box 13 and
The water tank emergency valve V is constituted by the valve main body 14 constituted by a spool valve. As shown in FIGS. 4 and 5, the emergency valve V is mounted on the valve box 13, the valve rod 14E, and one axial end of the valve rod 14E. Large diameter piston part 14A, valve stem 14E
Large-diameter first valve body 1 mounted near the other end in the axial direction
4B, a valve body having a large-diameter piston portion 14F attached to the other axial end of the valve stem 14E and a large-diameter second valve body portion 14C attached to a substantially central portion of the valve stem 14E in the axial direction. 14 may constitute a water tank emergency valve V. In this case, as shown in FIG. 6, the valve body 14 from which the large-diameter piston portion 14F is omitted is used, and the valve rod 14E is protruded from the other axial end of the valve box 13 to the outside. A biasing means 15 is provided by a lever 22 which is pin-connected to the elongated hole 22a and whose tip is rotatably pin-connected to the valve box 13 and a counterweight 23 which is attached to the lever 22 so as to be movable in the axial direction. May be configured.

[0024]

As described above, according to the first and second aspects of the present invention, the number of valves to be used is reduced to one, and when an abnormal situation occurs, the water distribution through the water distribution main pipe cannot be secured. In addition, it is possible to reduce the probability of occurrence of inconvenience that the inflow of sewage into the water storage tank cannot be prevented, to improve the reliability, and to reduce the installation space and ease the space restrictions. In addition, by omitting the use of piping materials with a complicated structure and installing it in the pipeline between the water distribution main pipe and the water storage tank, it can be operated urgently in the event of an abnormal situation such as breakage of the water distribution main pipe, and As it can prevent the inflow of sewage into the tank and ensure water flow through the distribution mains,
Easy to make.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a normal state of the present invention.

FIG. 2 is a configuration diagram showing one embodiment of the present invention when an abnormal situation occurs.

FIG. 3 is a diagram corresponding to FIG. 1 showing a modification of the urging means.

FIG. 4 is a configuration diagram showing another embodiment of the present invention in a normal state.

FIG. 5 is a configuration diagram showing another embodiment of the present invention when an abnormal situation occurs.

FIG. 6 is a view corresponding to FIG. 4, showing a modification of the urging means.

FIG. 7 is a configuration diagram showing a conventional example in a normal state.

FIG. 8 is a configuration diagram showing a mode when an abnormal situation occurs in a conventional example.

FIG. 9 is a configuration diagram showing a form of another conventional example in a normal state.

FIG. 10 is an enlarged sectional view taken along the line AA of FIG. 9;

FIG. 11 is a configuration diagram showing a mode when an abnormal situation occurs in a conventional example.

FIG. 12 is an enlarged sectional view taken along line BB of FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water distribution main pipe 1A Upstream main pipe 1B Downstream main pipe 2 Seismic storage tank (water storage tank) 2A Inlet 2B Outlet 13 Cylindrical valve box 14 Valve body 15 Energizing means 16 Pressure chamber (One end in the axial direction of the valve box) P1 First inflow port P2 First outflow port P3 Second outflow port P4 Second inflow port P5 Pilot port V Emergency valve for water storage tank

Claims (2)

[Claims] 1. A valve body comprising: a cylindrical valve box; and a valve main body which is mounted inside the valve box so as to be movable in an axial direction, and the peripheral wall portion of the valve box is spaced apart in the axial direction. A first inflow port communicating with the upstream main pipe of the water distribution main pipe and a first outflow port communicating with the downstream main pipe of the water distribution main pipe are formed at the closed position, and from the first inflow port and the first outflow port. A second outflow port and a second inflow port are formed at positions spaced apart from each other in the circumferential direction of the valve box and at both ends in the axial direction, respectively, and communicate with the inlet and the outlet of the water storage tank, respectively. A pilot port for introducing the water pressure of the water distribution main pipe into the inside as a pilot pressure to apply a moving force to the valve body in one axial direction, and the valve body in the other axial direction against the pilot pressure. Biasing means for biasing toward In a region where the water pressure of the water distribution main pipe exceeds a set value, the valve body is moved to one side in the axial direction of the valve box against the urging of the urging means by the pilot pressure, and the first inflow port and the first inflow port are moved. (2) The outflow port and the first outflow port communicate with the second inflow port, and in a region where the water pressure of the water distribution main pipe is equal to or lower than a set value, the urging means biases the valve body to the other end in the axial direction of the valve box. An emergency valve for a water storage tank, which is configured to move toward the side to communicate the first inflow port and the first outflow port. 2. A valve body comprising: a cylindrical valve box; and a valve body which is axially movably mounted inside the valve box, and a peripheral wall portion of the valve box has an interval in its axial direction. And a first inflow port communicating with the upstream main pipe of the water distribution main pipe and a first outflow port communicating with the downstream main pipe of the water distribution main pipe are formed. The first inflow port is separated from the first inflow port in the circumferential direction of the valve box, and A second outflow port communicating with the inlet of the water storage tank is formed at a position distant to one end in the axial direction, a position in the circumferential direction of the valve box away from the first outflow port, and a position distant to the other end in the axial direction. A second inflow port communicating with an outlet of the water storage tank is formed, and a pilot port for introducing the water pressure of the water distribution main pipe into the inside as an pilot pressure at one axial end of the valve box to load the valve body. Is provided at the other end in the axial direction of the valve box to oppose the pilot pressure. An urging means for urging the valve body is provided, and in a region where the water pressure of the water distribution main pipe exceeds a set value, the valve body is moved to the valve box against the urging of the urging means by the pilot pressure. To the other end in the axial direction to communicate the first inflow port with the second outflow port and the first outflow port with the second inflow port, and in the region where the water pressure of the water distribution main pipe is equal to or lower than a set value, the urging is performed. An emergency valve for a water tank, wherein the urging means moves the valve body to one axial end of the valve box to communicate the first inflow port and the first outflow port.