JPH109421A - Pressure perception type pilot valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the pilot valve for return and interception for a flow passage selector valve by one valve, in an emergency water tank equipment. SOLUTION: A valve element 25 in a valve casing 20 divided in three can be contacted alternatively to first/second valve seats 26a, 26b. A valve rod 23 is moved vertically along with a diaphragm 32 and this movement is decided by the pressure from a pilot port 27 and the energized force of a spring 35. The energized force is adjusted by a bolt 37 and the valve element 25 regulates a pilot pressure 27 contacting/separating to/from the valve seats 26a, 26b. This adjust pressure makes a changeover pressure of the open/close of the flow passages 27a of the first/second ports 21a, 21b and the open/close of the flow passages 27b of the second/third ports 21b, 21c and the open/close changeover of both flow passages 27a, 27b can be carried out simultaneously. When both flow passages 27a, 27b make the open/close flow passages of pilot valve for return and interception of the flow passage selector valve in an emergency water tank equipment, the operation of both valve can be carried out by one valve V1 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow path switching valve which is installed in a pipe connecting an emergency water storage tank and a water main pipe used in an earthquake disaster or the like to change respective flow paths. The present invention relates to a device and a pressure sensing type pilot valve used for the device.

[0002]

2. Description of the Related Art Conventionally, emergency water tanks (tanks) are provided in roads, schoolyards or underground parks, for example, in order to secure living water for local residents in the event of a disaster such as an earthquake or to provide water for fire extinguishing. It is buried.

[0003] In this emergency water storage tank equipment, generally, as shown in Fig. 8, a bypass pipe P is provided in a water main pipe S, a water storage tank (tank) T is interposed in the bypass pipe P, and a bypass pipe P is provided. Emergency shut-off valves 1 and 1 are provided on the outflow and inflow side of P, respectively, and an emergency open valve 2 is installed in the water main S between the bypass pipes P.
Is provided. In the figure, 3 is a fire hydrant, 4 is a manual pump, and 5 is an air valve.

In normal times, the emergency shutoff valves 1 and 1 are opened, the emergency release valve 2 is closed, and water flows as indicated by arrows a, b, c and d to store water in the water storage tank T. ,
Rotation is prevented by preventing water from stagnating in the water storage tank T. On the other hand, in an emergency (emergency) such as an earthquake,
The emergency shutoff valves 1 and 1 are closed, the emergency release valve 2 is opened, the flow of the water main S is secured, the water storage tank T is cut off from the water main S, and the water from the water storage tank T due to the siphon phenomenon is generated. Prevent runoff and secure water.

In this emergency water storage tank facility, various techniques for controlling the emergency shutoff valve 1 and the emergency release valve 2 by the water pressure of the water main S have been developed. For example, Japanese Utility Model No. 3018335 The gazette discloses one example. Further, as a similar prior art, as shown in FIG. 9, there is an emergency shutoff valve 1 and an emergency release valve 2 provided with two pilot valves 6 and 7.

In the prior art, for example, in the case of an emergency shutoff valve 1, two emergency return and shutoff pilot valves 6, 7 are attached to the emergency shutoff valve 1 interposed in a bypass pipe P, and the pilot Valves 6 and 7 are respectively provided with diaphragms 6a and 7a, springs 6b for pushing the diaphragms,
7b, a valve element 6c interlocked with the diaphragm via a valve stem,
7c and its valve seats 6d and 7d. During normal times when the water pressure is equal to or higher than the required pressure, the water pressure is applied to both pilot valves 6 and 7 as shown in FIG.
The diaphragms 6a and 7a compress the springs 6b and 7b, and the valve element 6c moves away from the valve seat 6d, and the valve element 7c presses against the valve seat 7d to apply no water pressure to the cylinder valve 11a of the emergency shut-off valve 1. For this reason, the cylinder valve 11a
The internal and external pressures are P ₁ > P ₂ , and the pressure is separated from the valve seat 12,
The shutoff valve 1 is open.

On the other hand, when the water pressure drops due to an earthquake or the like and becomes lower than the urging force of the springs 6b, 7b, as shown in FIG. 1B, the pilot valves 6, 7 are attached to the springs 6b, 7b. Due to the force, the valve element 6c contacts the valve seat 6d, the valve element 7c separates from the valve seat 7d, and the water pressure is applied to the cylinder 11 (P ₁ ≒ P ₂ ). In this case, the diameter D ₂ of the emergency shut-off valve 1 of the valve seat diameter D ₁ and the cylinder 11 D ₁
<There is relationship _{D 2, π / 4 · D} 1 2 · P 1 <π / 4 · D
₂ ² · P ₂ + W (weight of cylinder valve 11a)
The cylinder valve 11a contacts the valve seat 12 to close the pipe P.

[0008]

As described above, the provision of the two pilot valves 6 and 7 requires a large installation space, complicates the piping of the pressure guiding tube t, and reduces the cost. Will be higher. Also, two valves 6,
7, the failure occurrence rate is also high.

Further, it is necessary to correlate the set pressures of the pilot valves 6 and 7, and the adjustment is complicated. If there is a problem in the adjustment, the required operation is not performed. That is, where the set pressure of both pilot valves 6 and 7 should be 5 kg / cm ² , only the set pressure of return pilot valve 6 is adjusted to 4 kg / cm ^{2 because} the pressure of spring 6b is weak and too low. When the line P falls below the normal pressure to a set pressure (5 kg / cm ² ), the shutoff pilot valve 7 operates normally (from closed to open) and the pressure water in the line P Is supplied into the cylinder 11. However, since the return pilot valve 6 does not operate because the water pressure has not dropped to the set pressure of 4 kg / cm ² (it remains open), even if pressure water is supplied, the pressure water is almost directly discharged to the outside. Will be discharged. For this reason, even if the pressure in the cylinder 11 increases slightly, it does not reach the predetermined pressure, so that the cylinder valve 11a does not reliably press against the valve seat 12 and the shutoff valve 1
Does not completely close, and the water on the upstream side continues to leak to the downstream side of the valve 1.

At this time, the pressure of the cylinder 11 is
Although determined by the difference between the supply and discharge of the pressurized water, the fluid pressure (water pressure), flow rate, valve (cylinder valve 11) opening degree of the pipe P,
And the like, the degree of opening of the valve 1 and the like are not constant, become unstable, and the amount of leakage to the downstream side does not become stable.
The piping system becomes extremely unstable and malfunctioning. Such an unstable state may occur when there is a difference in the length of the pressure guiding tube t of the valves 6 and 7 or when there is a leak. For this reason, it is necessary to consider the length and leakage of the pressure guiding tube t for the set pressure of both valves 6 and 7, and the adjustment is complicated.

On the other hand, if the set pressure of the shutoff pilot valve 7 is too low, for example, 4 kg / cm ² , the water pressure in the pipeline P drops to 5 kg / cm ² , and even if the return pilot valve 6 is closed, Since the shutoff pilot valve 7 does not operate (does not open), the pressure water is not supplied into the cylinder 11, and in this case also, the shutoff valve 1 does not close and enters an unstable open state.

In the above both unstable states, when the water pressure in the pipeline P further decreases to 4 kg / cm ² , the return pilot valve 6 or the shutoff pilot valve 7 is activated (closed or opened) at that time. ), All the pressure water is in cylinder 11
To shut off the shut-off valve 1 stably and reliably.

In accordance with the present invention, the present invention provides a pilot valve which is easy to adjust the pressure by eliminating complicated and long pressure introducing pipes as much as possible and which has less troubles. It is a main object to provide a flow path switching valve device in the used emergency water storage tank equipment.

[0014]

In order to achieve the above object, the present invention is such that the return and shutoff pilot valves are formed in a single valve box. According to the invention, the first valve seat and the flow of the second and third ports are provided in the flow path of the first and second ports in the valve box having the first, second and third three ports. A second valve seat is formed in each of the passages, the two valve seats are positioned on the same axis, and a valve stem is provided on the axis, and the valve stem alternately comes into contact with and separates from the valve seats on the valve stem. And a cylinder in which the valve rod is inserted is mounted on the valve box, and a diaphragm interlocked with the valve rod is provided in the cylinder, a pilot pressure is applied to the diaphragm, and the diaphragm is controlled by the pilot pressure. Provide a spring that biases in the direction opposite to the The pilot pressure or is had a configuration approaching and moving away from the valve body to move the valve stem through the diaphragm by the spring in the axial direction alternately from both the valve seat.

The pressure sensing type pilot valve thus configured adjusts the pilot pressure at which the valve body comes into contact with or separates from the valve seat by adjusting the biasing force of the spring. This adjustment pressure is a switching pressure for opening and closing the flow path between the first port and the second port and for opening and closing the flow path between the second port and the third port. That is, by adjusting the urging force of the spring, the two channels can be simultaneously opened and closed. For this reason, if the two flow paths are the open / close flow paths of the return and shut-off pilot valves, the action of both valves can be performed by one valve (see the embodiments of the invention described later).

According to a second aspect of the present invention, in the first aspect of the present invention, the valve box includes a first piece having a first port, a second piece having a second port,
The valve body is divided into a third piece having a third port, and the second piece is interposed between the first and third pieces and bolted to form the valve box. Each of the valve seats is formed, and the valve element is provided inside the second piece.

In this way, the manufacture of each piece becomes easy, and if each piece is bolted with a seal interposed therebetween, it becomes a valve box, which is easy to assemble. In addition, the valve body also moves linearly and opens and closes by pressing against the valve seat in the direction of movement, so that the operation is reliable and the sealing performance is good.

The invention according to claim 3 or 4 relates to a flow path switching valve device using the above-mentioned pressure sensing type pilot valve, and the invention according to claim 3 relates to an emergency water storage tank in a water main. A flow path switching valve is provided between the water main pipe and the bypass pipe to open and close the communication between the water main pipe and the bypass pipe so that the flow of the water main pipe does not pass through the bypass pipe. In the emergency water storage tank equipment provided, a pressure sensing pilot valve according to claim 1 or 2 is attached to the flow path switching valve, and the flow path switching is performed by the pilot valve using the water pressure of the water main as the pilot pressure. The valve is operated.

As a configuration for operating the flow path switching valve, for example, in the case of the shut-off valve 1 in FIG. 9, the pipe pressure is introduced into the first port or the third port, and the second port is connected to the cylinder 1
1, the third port or the first port is opened, and the valve body is moved by the pilot pressure (pipe line pressure) to open and close both valve seats. The application of pressure is switched, and the flow path switching valve is operated (see an embodiment described later).

According to a fourth aspect of the present invention, in the third aspect of the present invention, the shut-off valve 1 and the on-off valve 2 shown in FIG. 9 can be formed by a single valve. The flow path switching valve having the following configuration (A) is connected with a bypass pipe or a water main pipe at the first and fourth ports of the flow path switching valve, and a water main pipe or a bypass pipe at the second and third ports. Then, the piston in the following cylinder of the flow path switching valve is moved by application of the pilot pressure through the pilot valve,
In normal times when the water pressure of the water main is high, the valve body is separated from the first and third valve seats of the flow path switching valve, and the valve body comes into contact with the second valve seat. , The first and third valve seats respectively contact the valve body and the second
The valve body is separated from the valve seat.

Configuration (A) "A valve rod that slides on the same axis is provided in a valve box, and partition walls crossing the valve rod are provided at three axial positions of the valve rod. First, second, third, and fourth chambers are sequentially divided in the axial direction, ports are formed in the respective chambers, and communication holes through which the valve stem penetrates are formed in the partition walls. A first valve seat is provided on the periphery of the communication hole between the first chamber and the second chamber, and a second valve seat is provided on the periphery of the communication hole between the second chamber and the third chamber.
A third valve seat is provided on the periphery of the communication hole of the valve seat, the third chamber and the fourth chamber, and a valve body is provided on the valve rod to open and close the communication hole by coming into contact with and separating from the valve seat. Each valve element is the first
And when it comes into contact with the third valve seat, it separates from the second valve seat, and when it comes into contact with the second valve seat, it separates from the first and third valve seats. Provide an inserted cylinder and a piston in the cylinder that is linked to the valve stem. "

In the flow path switching valve device configured as described above, for example, the water pressure of the water main is introduced into the pilot port and the first port of the pressure sensing type pilot valve, and the second port is connected to the cylinder of the flow path switching valve. At the same time, the third port is opened to the outside (see an embodiment described later). With such piping, by the above action by the pilot valve,
The water pressure of the water main is appropriately applied to the cylinder, and the valve stem of the flow path switching valve automatically moves through its piston,
The above two states are alternatively performed, and a normal or emergency operation is performed. In particular, even when the flow path switching valve is brought into an emergency state due to a temporary decrease in the water pressure, when the water pressure is restored, the water path is automatically returned to a normal state, and the water in the storage tank stagnates and rots. Not even.

[0023]

DETAILED DESCRIPTION OF THE INVENTION One embodiment of a pressure sensitive pilot valve V ₁ shown in FIGS. 1 to 3, in that figure, 20
Is a valve box having a first port (port) 21a.
(Divided body) 20a, a second piece (divided body) 20b having a second port (mouth) 21b, and a third piece (divided body) 20c having a third port (mouth) 21c, which will be described later. 20d that forms part of the cylinder 30
At the same time, the pieces 20a, 20b, 20c and the lid 20d are integrated with each other by being tightened by the bolt 22 with the O-ring 21 interposed therebetween. An appropriate number of bolts 22 are provided at equal circumferential positions.

A valve stem 23 is inserted into the center of the valve box 20.
The valve stem 23 is slidably fitted in a sliding hole 24 of the third piece 20c via an O-ring 24a, and the sliding (moving) causes the valve body 25 fixed to the valve stem 23 to move. Move in the axial direction. From the first port 21a to the second port 21
b of the first piece 20a of the flow path 27a to the first valve seat 2
6a, a second valve seat 26b is formed in the third piece 20c of the flow path 27b from the second port 21b to the third port 21c, and rubber sheets 25a, 25b on the upper and lower surfaces of the valve body 25 are formed. In accordance with the movement of the valve body 25, it alternately comes into contact with and separates from the two valve seats 26a, 26b. That is, the valve body 25
, The two flow paths 27a and 27b are selectively opened and closed. A valve body 25 that comes into contact with and separates from both valve seats 26a, 26b
Are one rubber sheet 25a and the other rubber sheet 25b
It may be divided into sides.

A cylinder 30 is formed by screwing a covered tubular body 31 into the lid 20d, and a diaphragm 32 such as Velofram (trade name of Fujikura Rubber Co., Ltd.) is stretched in the cylinder 30. ing. The periphery of the diaphragm 32 is sandwiched between the third piece 20c and the lid 20d to define the inside of the cylinder 30, and the valve stem 23 penetrates the center of the cylinder. A piston 33 and a retainer 34 are fixed to the penetrated valve stem 23 with a diaphragm 32 interposed therebetween. Therefore, the valve stem 23 moves up and down via the piston 33 according to the deflection of the diaphragm 32.

A spring 35 is provided inside the cylindrical body 31. The lower end of the spring 35 is in contact with the piston 33 and the other end thereof is in contact with (received) a spring receiver 36. The spring receiver 36 is provided on the cylindrical body 3 in accordance with the screwing amount of the bolt 37.
1 to move the spring 35 in and out. Therefore, the urging force of the spring 35 is adjusted by the screwing amount of the bolt 37, and the movement of the valve rod 23, that is, the valve body 25 is moved to the valve seat 26.
The pressure applied to the diaphragm 32 that comes into contact with and separates from the a and 26b can be adjusted. The application is performed through a pilot port 27 formed in the third piece 20c.

The embodiment of the pressure sensing type pilot valve V ₁ has the above configuration. As shown in FIG. 2, when a pilot pressure p such as tap water pressure is applied to the diaphragm 32, the pressure p When the pressure is higher than the pressure set by the spring 35, the diaphragm 32 is bent upward by the pressure p, the valve rod 23 is also raised, and the valve body 25 is moved to the second valve seat 26b as shown in FIG. Pressure contact, 1st port 2
The flow path 27a between 1a and the second port 21b is open, and the flow path 27b between the second port 21b and the third port 21c is closed.

In this state, if for some reason, such as an earthquake, the water pressure of the water main S falls and the pilot pressure p decreases and becomes lower than the pressure set by the spring 35, as shown in FIG. As a result, the diaphragm 32 bends downward, the valve rod 23 also descends, and the valve body 25 separates from the second valve seat 26b, comes into pressure contact with the first valve seat 26a, and the flow path 27a
Is closed, and the flow path 27b is opened.

In this embodiment, a pilot pressure p may be applied to the side of the spring 35 in the cylinder 30 so that the spring 35 urges the piston 33 upward in the extended state. At this time, the valve body 25 is pressed against the second valve seat 26b by the urging force of the spring 35.

Next, the pressure sensing type pilot valve V ₁
3 to 7 show an embodiment in which the embodiment of FIG. 8 is used for the emergency water storage tank equipment of FIG. 8, and FIGS. 3 and 4 show the shut-off valve 1 (FIG. 3) and the release valve 2 (FIG. 4) of FIG. ), And the configuration of the valves 1 and 2 is the same as that described above.
The description is omitted.

[0031] In the case of cut-off valve 1 shown in FIG. 3, by introducing a pressure conduit (bypass pipe) P to a pilot port 27 and the third port 21c of the pilot valve V _1, a second port 21
b to the cylinder 11 and the first port 21
Release a.

In this valve device, the diaphragm 32 flexes upward due to the hydraulic pressure p to press the valve body 25 against the second valve seat 26b in normal times, as shown in FIG.
Is open, and the inside of the cylinder 11 is open to the outside. Therefore, from P ₁ > P ₂ , the cylinder valve 11 a rises, the valve seat 12 is opened, and the shutoff valve 1 is in the open state.
Tap water circulates in the pipeline P.

On the other hand, the water pressure p decreases due to an earthquake or the like,
When the pressure becomes lower than the set pressure by the spring 35, the spring 35
As shown in FIG. 3B, the diaphragm 32 bends downward to separate the valve body 25 from the second valve seat 26b, and the first valve seat 2
6a. For this reason, the water pressure p in the pipe P is applied from the second port 21b into the cylinder 11, and the cylinder valve 11a descends and presses against the valve seat 12 to close the pipe P in the same manner as described above.

When the water pressure in the pipeline P returns and becomes equal to or higher than the set pressure, the diaphragm 32 bends upward and the pilot valve V
₁ returns to open the pipe P as shown in FIG.

[0035] In the case of an open valve 2 shown in FIG. 4, introducing pipe water pressure p of (water main) S to the pilot port 27 and the first port 21a of the pilot valve V _1, a second port 21
b to the cylinder 11 and the third port 21
Release c.

This valve device operates in a reverse manner to the case of the shut-off valve 1 described above, and normally, the diaphragm 32 is operated by the hydraulic pressure p.
Is bent upward to press the valve body 25 against the second valve seat 26b, the first valve seat 26a is opened, the hydraulic pressure p is applied in the cylinder 11, the cylinder valve 11a is lowered, and The pipe S is closed by pressure.

On the other hand, due to an earthquake or the like, the water pressure p decreases,
When the pressure becomes lower than the set pressure by the spring 35, the spring 35
As shown in FIG. 3B, the diaphragm 32 bends downward to separate the valve body 25 from the second valve seat 26b, and the first valve seat 2
6a. Therefore, the water pressure in the pipe S is not applied to the inside of the cylinder 11, but is opened to the outside through the third port 21c, the cylinder valve 11a rises and separates from the valve seat 12, and the pipe S is opened.

When the water pressure in the pipe S returns and becomes equal to or higher than the set pressure, the diaphragm 32 bends upward and the pilot valve V
₁ returns to the state shown in FIG.

FIG. 5 shows an embodiment in which the shut-off valve 1 and the opening valve 2 in FIG. 8 are formed by one flow path switching valve V ₂ , in which FIG. (Port) 41a and one divided body 40a having a second port (port) 41b, another divided body 40b having a third port (port) 41c and a fourth port (port) 41d, and one divided body 40a And two lids 40a.
And 40b, and one of the divided bodies 40a and the lid 40c are integrated by a bolt 43 with a packing (seal) 42 interposed therebetween. The bolt 43 is provided at an appropriate position around the periphery.

A valve stem 44 is inserted into the center of the valve box 40.
The valve stem 44 is supported movably in the axial direction by a lid 40c and bearings 45a, 45b on the bottom surface of the other divided body 40b. Further, inside the valve box 40, partition walls 46a, 46b, 46c crossing the valve stem 44 are provided, and the first chamber 47a of the first port 41a, the second chamber 47b of the second port 41b, and the third chamber 41b of the third port 41c are provided. It is divided into four chambers of a third chamber 47c and a fourth chamber 47d of a fourth port 41d.

The partition walls 46a, 46b, 46c are formed with communication holes 48a, 48b, 48c through which the valve rod 44 penetrates, and the peripheral edges of the holes 48a, 48b, 48c have first, second, and third valves. The seats 49a, 49b, and 49c are provided. The valve stem 44 is provided with valve bodies 50a, 50b that come into contact with and separate from the valve seats 49a, 49b, 49c, and the lower valve body 50b contacts the second valve seat 49b as shown by the solid line in FIG. When in contact with each other, the upper valve body 50a is separated from the first valve seat 49a, and the lower valve body 50b is
When the third valve seat 49c abuts away from the valve seat 49b, the upper valve body 50a comes into contact with the first valve seat 49a. Valve seats 49a, 49b, 4 of the valve bodies 50a, 50b
A seal 51 is provided on the contact surface with 9c to ensure watertightness.

The upper portion of the lid 40c of the valve box 40 is cylindrical, and a cylinder with a lid is screwed into the cylindrical portion to form a cylinder 52. The upper end of the valve rod 44 is inserted into the cylinder 52. The piston 53 is fixed to the end. This piston 53 is pushed downward by a spring 54. The spring 54 is controlled by an adjusting screw 55 to a spring receiver 56.
And the urging force is determined by the screwing amount of the screw 55.

The second port 21b of the pilot valve V ₁ on the opposite side of the spring 54 of the cylinder 52 is connected, the manual valve 57a in the conduit t, 57 b are Ben設usually
The one manual valve 57a is opened, and the other manual valve 57a is opened.
b is closed. To the pilot port 27 and the first port 21a of the pilot valve V ₁ was introduced pressure water mains S, the third port 21c is open.

[0044] In this connected state, the normal state is water pressure in the water main S also has a predetermined value, the water pressure applied to the cylinder 30 of the pilot valve V _1, as in the figure solid lines,
The diaphragm 32 flexes upward, and the valve body 25 is moved to the second valve seat 2.
6b. For this reason, the water pressure of the water main pipe S is applied to the cylinder 52 from the first port 21a through the second port 21b, and the piston 53 compresses the spring 54 and moves upward as indicated by the solid line in FIG. (Dead center position), the valve rod 44 is also positioned upward, the valve element 50b abuts on the second valve seat 49b, and the valve element 50a maintains a state separated from the first valve seat 49a. In this state, the first chamber 47a and the second chamber 47
b, the third chamber 47c and the fourth chamber 47d communicate with each other, and the water in the water main S is filled with the first port 41a and the second port 41b or the third port 41 as shown by the solid line or the dotted line in FIG.
It flows between c and the fourth port 41d, and passes through the water storage tank T.

On the other hand, during an emergency such as an earthquake, the water pressure in the water main S drops. This water pressure drop, as shown in chain line figure, the diaphragm 32 of the pilot valve V ₁
Is bent downward by the spring 35, and the valve body 25 is moved to the second valve seat 26.
b and presses against the first valve seat 26a. Therefore, the inside of the cylinder 52 is opened to the outside through the second port 21b and the third port 21c, and the piston 53 is lowered by the spring 54 (bottom dead center position) as shown by the chain line in FIG. And the valve body 50b separates from the second valve seat 49b and contacts the third valve seat 49c, and the valve body 50a
It contacts the valve seat 49a. In this state, the second chamber 47b and the third chamber 47c communicate with each other, and the first and fourth chambers 47a and 47d are shut off from the second and third chambers 47b and 47c.
The water in the water main S flows between the second port 41b and the third port 41c as indicated by the solid line or the dotted line in the figure, and the water in the water storage tank T does not flow out.

In the closed state of the water storage tank T, when the water pressure of the water main S increases and returns to a required value, as described above,
Water pressure in the cylinder 52 is applied through the pilot valve V _1, by the required pressure, the piston 53 returns to the condition shown in FIG solid line is moved upward. That is, even if the water pressure in the water main S is temporarily reduced for some reason, the state automatically returns to the state of flowing water to the water storage tank T.

Incidentally, in an emergency, the above-mentioned shutoff operation between the water storage tank T and the water main pipe S can be performed by closing one manual valve 57a and opening the other manual valve 57b. The manual valves 57a and 57b may be electromagnetic valves. Also,
Both valve 57a, 57 b may be made by one of the valve 57 similar to the pilot valve V ₁ configured as shown in FIG. That is, as shown by the solid line or the chain line in FIG.
Accordingly, the valve body 57c can be selectively connected to and separated from the two valve seats 57d.

The embodiment shown in FIG. 7 employs a single-acting piston-type hydraulic cylinder driving system instead of the spring-back hydraulic cylinder driving system in the embodiment of FIG. That is, the cylinder 52 has a different diameter in the middle, a cylindrical piston 58 is provided inside the cylinder 52 via seals 59a and 59b, and the pressure water of the water main pipe S is supplied to one port of the cylinder 52. Introduce,
It is obtained by connecting the second port 21b of the pilot valve V ₁ to the other ports. That pilot valve V ₁ was pressure water mains S is introduced to the pilot port 27 and the third port 21c, the first port 21a is open.

[0049] This embodiment, when normal, as in the figure solid lines, the valve body 25 of the pilot valve V ₁ is pressed against the second valve seat 26b, the cylinder 52 is applied directly to the water supply pressure, the pilot valve V Not applied via ₁ . For this reason, the piston 58 rises as shown by the solid line, the valve rod 44 also moves upward, and each of the valve bodies 50a and 50b also becomes a solid line state, and tap water flows through the water storage tank T as shown by a solid line or a chain line as described above. Flows.

On the other hand, in an emergency, as in FIG chain line, the valve body 25 of the pilot valve V ₁ is pressed against the first valve seat 26a,
Water pressure is applied to both sides of the piston 58 in the cylinder 52. At this time, the piston 58 descends as indicated by a dashed line and the valve rod 44 also moves downward due to the difference in the application area of the water pressure on both side surfaces of the piston (upper and lower diameters of the cylinder 52).
0a and 50b are in a chain line state, and the water storage tank T is cut off from the water main pipe S.

[0051]

The present invention is constructed as described above, and as a pilot valve for a flow path switching valve in an emergency water storage tank facility, it is possible to perform a return operation and a shutoff operation with a single valve. Adjustment of the set pressure is easy and trouble is reduced. In addition, the fact that the number of valves can be reduced also reduces the number of piping of the pressure guiding tube, which is advantageous in terms of cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment of a pressure-sensitive pilot valve.

FIG. 2 is an operation explanatory view of the embodiment.

FIG. 3 is an operation explanatory view of one use mode of the embodiment.

FIG. 4 is an operation explanatory view of another usage mode of the embodiment.

FIG. 5 is a cross-sectional view of another embodiment.

FIG. 6 is a cross-sectional view of another embodiment.

FIG. 7 is a cross-sectional view of another embodiment.

FIG. 8 is an explanatory view of an emergency water storage tank facility.

FIG. 9 is a diagram illustrating the operation of a conventional example.

[Explanation of symbols]

P bypass pipe p Water pressure (pressurized water) S mains T reservoir (tank) V ₁ pilot valve V ₂ channel switching valve 1 emergency shutoff valve 2 emergency release valve 11 cylinder 11a cylinder valve 12 valve seat 20 valve body 20a , 20b, 20c Valve box split piece 21a First port 21b Second port 21c Third port 23 Valve rod 25 Valve body 26a, 26b Valve seat 27 Pilot port 30 Cylinder 32 Diaphragm 35 Spring 40 Valve box 41a, 41b, 41c, 41d Port (port) 44 Valve stem 46a, 46b, 46c Partition wall 47a First chamber 47b Second chamber 47c Third chamber 47d Fourth chamber 48a, 48b, 48c Communication hole 49a First valve seat 49b Second valve seat 49c Third Valve seat 50a, 50b Valve body 52 Cylinder 53, 58 Piston 54 Spring

Claims (4)

[Claims] 1. First, second and third three ports 21
a, 21b, 21c in the valve box 20
The first valve seat 26 is provided in the flow path 27a of the ports 21a and 21b.
a, a second valve seat 26b is formed in the flow path 27b of each of the second and third ports 21b and 21c.
a and 26b are located on the same axis, and the valve stem 23
The valve stem 23 is provided with a valve body 25 which alternately comes into contact with and separates from the two valve seats 26a, 26b. The valve box 20 includes a cylinder 3 into which the valve stem 23 is inserted.
And a diaphragm 32 interlocking with the valve rod 23 is provided in the cylinder 30 so that the diaphragm 3
2 applies a pilot pressure to the diaphragm 2 and urges the diaphragm 32 in a direction opposite to the pilot pressure.
When the pilot pressure exceeds a set value, the valve rod 25 is moved in the axial direction of the valve rod 23 via the diaphragm 32 by the pilot pressure or the spring 35 to alternately move the valve body 25 between the two valve seats 26a and 26b. A pressure-sensitive pilot valve that comes in contact with and separates from the pilot valve. 2. The valve box 20 is provided with a first piece 20a having a first port 21a, a second piece 20b having a second port 21b, and a third piece having a third port 21c. 20c, the first and third pieces 2
The valve box 20 is configured by interposing the second piece 20b between the first and second parts 0a and 20c and tightening the bolt 22.
Each of the valve seats 26a, 26b is attached to the third piece 20a, 20c.
And the valve element 2 in the second piece 20b.
5. The pressure sensing type pilot valve according to claim 1, wherein the pressure sensing type pilot valve is provided. 3. A bypass pipe P provided with an emergency water storage tank T in the water main pipe S, and its communication is opened and closed between the water main pipe S and the bypass pipe P, and The flow path switching valve V that makes the flow pass through and bypasses the bypass pipe P
In emergency water tank equipment in which a _2, and attaching a pressure sensitive pilot valve V ₁ of the claims 1 or 2, wherein in the flow path switching valve V _2, the pressure of the water mains S as the pilot pressure, flow path switching valve device in the emergency reservoir equipment being characterized in that so as to operate said flow path switching valve V ₂ by the pilot valve V _1. 4. The flow path switching valve V ₂ has the following configuration (A)
And then, first, the fourth port 41a of the flow path switching valve V _2,
Bypass pipe P or water main S to 41d, second, third port 41b, 41c to connect the mains S or bypass pipe P, the piston in the following cylinder 52 of the passage switching valve V ₂ 5
3 is moved by the application of the pilot pressure via the pilot valve V _1, and in normal times when the water pressure of the water main S is high, the first and third valve seats 49 a of the flow path switching valve V ₂ ,
The valve bodies 50a and 50b are separated from the valve body 49c, respectively, and the valve body 50b abuts on the second valve seat 49b. In the emergency when the water pressure is low, the valve bodies 50a and 50b are respectively provided on the first and third valve seats 49a and 49c. The flow path switching valve device according to claim 3, wherein the valve element (50b) is separated from the second valve seat (49b) while being in contact therewith. Configuration (A) “A valve rod 44 that slides on the same axis is provided in a valve box 40, and partition walls 46 a and 46 traversing the valve rod 44 are provided.
b, 46c are provided at three axial positions of the valve stem 44,
The inside of the valve box 40 is divided into first, second, third, and fourth four chambers 47a, 47b, 47c, and 47d in the axial direction, and ports 41a, 41b, and 41 are respectively provided in the respective chambers.
c, 41d are formed, and communication holes 48a, 48b, 48c through which the valve rod 44 penetrates are formed in the respective partition walls, and first communication holes 48a between the first chamber 47a and the second chamber 47b are formed around the communication holes 48a.
Communication hole 48 between valve seat 49a, second chamber 47b and third chamber 47c
b, the second valve seat 49b, the third chamber 47c and the fourth chamber 47d
The third valve seat 49c is provided on the periphery of the communication hole 48c, respectively.
The valve stem 44 is provided with valve bodies 50a, 50b which are in contact with and separate from the respective valve seats to open and close the communication holes, and the respective valve bodies are brought into contact with the first and third valve seats 49a, 49c. ,
When separated from the second valve seat 49b and comes into contact with the second valve seat 49b, it is separated from the first and third valve seats 49a and 49c, and the valve rod 44 is inserted into the valve box 40. The cylinder 52 is provided, and a piston 53 interlocked with the valve rod 44 is provided in the cylinder 52. "