JPH0596163U - Excessive flow prevention device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an excessive flow prevention device which has a simple structure and can be manufactured at low cost. [Structure] A flow rate control device is arranged in the water supply pipe of the water supply, and when the flow rate in the water supply pipe reaches a predetermined limit flow rate, the flow rate control device (14) is operated to limit the flow passage area and limit the maximum flow rate Do not exceed The flow rate control device has a movable restricting member (15) provided so as to face the internal flow path. A differential pressure generator (12) is provided in series with the flow rate controller, and the upstream side and the downstream side of the differential pressure generator are respectively
A conduit (1) is provided to the two liquid chambers of a cylinder device (16) whose interior is divided into two chambers by a displaceable partition means (17).
8 and 20) to communicate. Then, a connecting member (30) is provided so as to interlock the limiting member with the displacement of the partition device.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an excessive flow prevention device, and more particularly to an excessive flow prevention device used in water supply facilities, and more specifically, in a large-scale water supply device, when the amount of water used reaches a predetermined limit flow rate, The present invention relates to an excessive flow prevention device that limits the maximum amount of water to the limited flow rate and stabilizes water supply without impairing practical convenience.

[0002]

[Prior Art]

 Water supply is a system that originally supplies tap water to each household through a water supply pipe branched from the distribution pipe. In this case, the water supply system from the water supply pipe to the indoor water-using equipment is usually connected directly to the water distribution pipe. In recent years, even in the case of high demand such as in apartments and general buildings, the method of directly connecting to the water distribution pipe has been adopted instead of the conventional water tank method.

In this case, when designing a water supply device such as a water supply pipe, the peak flow rate is set to, for example, 80% of the maximum amount of water used by all the water use devices at the downstream end, and the peak flow rate is set to 80%. It is customary to design the water supply equipment according to the flow rate. By the way, in the case of direct water supply, the amount of water used directly affects the condition inside the distribution pipe. Therefore, if a large number of devices are used at the maximum usage amount at one time and the usage amount exceeds the above-mentioned set peak flow rate, a situation may occur in which the water supply pressure is insufficient on the downstream side of the distribution pipe.

[0004]

[Problems to be solved by the device]

 Therefore, the applicant, in Japanese Patent Application No. 3-22104, limits the maximum water supply to the limit flow rate when the amount of water used exceeds a predetermined limit flow rate without impairing practical convenience. , Provided an overflow prevention system to stabilize the water supply. However, in this system, a flow rate control device and a flow rate control device that directly controls the flow rate of the water supply pipe are installed, and a control device that operates the flow rate control device based on the signal from the flow rate measurement device is used. This control device can be configured by using an electronic circuit device or the like, but in that case, it becomes a relatively expensive system. Therefore, the purpose of this proposal is to provide an overflow prevention device that can be constructed at a relatively low cost.

[0005]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, in the excessive flow prevention device of the present invention, the flow rate adjusting device is provided in a flow path formed in the flow rate adjusting device and facing the flow path. And a flow rate limiting member operable to adjust the flow passage area. Then, a differential pressure generating device provided in the water supply pipe in series with the flow rate control device, a cylinder device having a housing and a displaceable partition means for partitioning the housing into two chambers, and a differential pressure generating device The upstream side and the downstream side each have a communicating means for connecting to one of the two chambers of the cylinder device, and a connecting member for interlocking the flow rate limiting member with the displacement of the partition means is provided. With this configuration, it is possible to limit the flow rate by directly moving the partition member using the pressure difference between the two sides of the differential pressure generating device, thereby interlocking the flow rate limiting member.

[0006]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a schematic configuration when an excessive flow prevention device according to a first embodiment of the present invention is arranged in a water supply pipe to an apartment house, 1 is a water pipe, 2 is a water pipe 1 It is a water supply pipe for the multi-dwelling housing 3 and the water supply capacity of the water supply device such as this water supply pipe is designed based on the peak flow rate determined as described above. Reference numeral 10 is an excessive flow prevention device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the configuration of the excessive flow prevention device 10. This device 10 is provided with an orifice 12 as a throttle device for generating a differential pressure arranged in the middle of the water supply pipe 2, and this orifice 12 And a sluice valve 14 provided in series with the flow rate restricting member 15 and a diaphragm 17 mounted on the sluice valve 14 and capable of moving the inside into two chambers A and B. It is provided with a partitioned cylinder device 16 and a pair of conduits 18, 20 as communication means for fluidly connecting the upstream side and the downstream side of the orifice 12 in the water supply pipe 2 to the chambers A, B of the cylinder device 16, respectively. ..

A Venturi tube or the like can be used instead of the orifice 12. In any case, when the shape of the orifice 12 is determined, it is generated between the upstream side and the downstream side of the orifice 12 by its throttling action. The pressure difference is a function of flow velocity. Since the flow rate is the product of the flow passage area and the flow velocity, once the shape of the orifice 12 is determined, the relationship between the flow rate and the pressure difference is determined.

A flow path 22 communicating with the water supply pipe 2 is formed in the sluice valve 14, and the valve body 15 as a flow rate restricting member has a valve body accommodating portion 23 provided on a side portion of the flow path 22. The flow path area in the sluice valve 14 is changed by being received in the interior of the sluice, facing the flow passage 22, and moving in the direction traversing the flow passage 22 in the present embodiment. Instead of the sluice valve, a valve whose flow rate can be adjusted by operating some member such as a globe valve can be used.

In this embodiment, the cylinder device 16 is mounted on the valve body storage portion 23 via the box-shaped bracket 24, but the bracket 24 is not always necessary. The cylinder device 16 is formed by upper and lower housing members 26 and 28, and the inside thereof is divided into two chambers, A and B, by a diaphragm 17 whose outer peripheral portion is sandwiched and fixed between the flange portions of the upper and lower housing members 26 and 28. It is divided. The chambers A and B are connected to the upstream side, that is, the high pressure side and the downstream side, that is, the low pressure side, of the orifice 12 by conduits 18 and 20, respectively. Therefore, the pressure force on the upstream side of the orifice 12 and the pressure force on the downstream side of the orifice 12 act on both sides of the diaphragm 17, and the diaphragm 12 is displaced according to the pressure difference, and its position is the elastic force and the pressure difference of the diaphragm 12 generated at that time. And are in a balanced position. Of course, instead of the diaphragm, it is possible to use a pierce peal that is sealed with honey. Further, instead of utilizing the elastic force of the diaphragm 17, a return spring may be used.

The stem 30 whose one end 32 is screwed onto the upper portion of the valve body 15 and fixed by the nut 36 passes through the upper wall of the valve body storage portion 23, penetrates through the bracket 24, and extends into the cylinder device 16. The other end 34 is attached to the center of the diaphragm 17 by a pair of retainers 38, 40 and nuts 42, 44. Therefore, since the valve element 15 is interlocked with the displacement of the diaphragm 17, the flow rate of the sluice valve 14 is determined by the position of the diaphragm.

As described above, a differential pressure according to the flow rate in the water supply pipe 2 is generated on both sides of the orifice 12, the diaphragm 17 and the valve body 15 are displaced according to the differential pressure, and the flow path in the sluice valve 22 is changed. Set the area. Therefore, if the shape of the orifice 12 is determined, the flow velocity and the differential pressure generated when the flow amount equivalent to the above-mentioned peak flow amount is determined. Due to the pressure difference, the area of the flow passage defined when the diaphragm 17 and the valve body 15 move is of a size that enables the maximum flow rate corresponding to the peak flow rate in relation to the flow velocity obtained earlier. The displacement amount of the diaphragm 17 and the shape of the valve body 15 may be determined so as to have the area. The orifice and the sluice valve may be arranged in the reverse order of this embodiment.

Next, a second embodiment of the excessive flow prevention device according to the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view showing the structure of the excessive flow prevention device 50. This device 50 is provided with an orifice 52 arranged in the middle of the water supply pipe 2 as a throttle device for generating a differential pressure, and an orifice 52 connected in series with the orifice 52. And a sluice valve 54 provided with a flow rate limiting member 56. The sluice valve 54 has a flow passage 58 communicating with the water supply pipe 2 inside thereof, and has a cavity portion 60, which is hollow and opens at an upper edge portion 62, in the upper portion thereof. A cylinder device 64 is fixedly attached to the upper edge 62 of the cavity 60 by appropriate means. This cylinder device has a housing 65 formed by upper and lower housing members 66 and 68, and the inside of the housing 65 is partitioned by partition means 70 into upper and lower liquid chambers 78 and 80. The partition means 70 is composed of a diaphragm 72 whose outer peripheral edge is sandwiched by the flange portions 67 and 69 of the upper and lower housing members 66 and 68, and a piston 74 which is integrated with the diaphragm 72 using a retainer 76. The stem or piston rod 82 is screwed at its lower end to the flow rate restricting member 56, extends upward in the cavity 60, penetrates the guide bush 86 mounted on the bottom wall 84 of the lower housing member 68, and then the inside of the housing 65. And is secured to the partition means 70 by means of a nut 88 at its upper end. Reference numeral 90 denotes a coil spring that biases the partition means 70, the flow rate limiting member 56, and the piston rod 82 upward.

The upper liquid chamber 78 communicates with the water supply pipe 2 at a position upstream of the orifice 52 via a conduit 94 as shown in the drawing. On the other hand, the lower liquid chamber 80 is a sluice valve via a plurality of through holes 92 provided in the bottom wall 84 of the lower housing member 68, the cavity 60, and the communication flow passage 57 formed in the flow rate limiting member 56. It communicates with the flow path 58 of 54. That is, in the second embodiment, one of the conduits in the first embodiment is omitted, and the flow passage 58 of the sluice valve 54, that is, the downstream side of the orifice 52, has a communication flow passage formed in the flow rate limiting member 56. 57, the cavity 60, and a plurality of through holes 92 provided in the bottom wall 84 of the lower housing member 68, which communicate with the lower liquid chamber 80.

Also in this embodiment, if the dimensions of the orifice 52 and the like are determined, the upstream side of the orifice 52 and the flow path 58 of the sluice valve 54, that is, the downstream side of the orifice 52 are determined depending on the flow rate of the water in the water supply pipe 2. A constant pressure difference is created between them, which causes the partition means 70 to move. Therefore, the surface area of the flow path defined when the partition means 70, that is, the flow rate restricting member 56 moves due to the differential pressure generated when a flow rate equivalent to the above-mentioned peak flow rate flows is previously obtained. The moving amount of the partition wall means 70, the shape of the flow rate restricting member 56, the strength of the panel 90, etc. are set so that the area is large enough to allow the maximum flow rate corresponding to the peak flow rate in relation to the flow velocity. It should be set.

In each of the above embodiments, the orifice or the venturi is used as the means for generating the differential pressure, but instead of these, the check valve used in the ordinary water supply pipe is used. It is possible to use valves, water taps or water meters. This is because these devices have an inherent head loss for a given flow rate. In such a case, it is of course possible to use these existing instruments as they are, and it is not necessary to newly provide an orifice or the like.

Next, a third embodiment of the present invention will be described with reference to FIG. The overflow prevention device 100 of the third embodiment has the same structure as that of the above-described second embodiment except that a flow control device 110 is further provided. Therefore, the same members are designated by the same reference numerals. The detailed description is omitted.

The flow control device 110 is arranged between the conduit 94 and the upper liquid chamber 78 in the housing 65, and controls the fluid communication between the conduit 94 and the upper liquid chamber 78.

The flow control device 110 in this embodiment is provided with two check valves, and a flow path 114 communicating between the conduit 94 and the upper liquid chamber 78 is formed in the valve box 112. There is. The flow path 114 is divided into two parallel first and second flow path portions 116 and 118 on the way. A check valve 120 that allows a flow from the conduit 94 side to the upper liquid chamber 78 and blocks a flow in the opposite direction is disposed in the first flow path portion 116, and the second flow path portion 118 has an upper liquid flow path 118. A check valve 130 is arranged to allow the flow from the chamber 78 side to the conduit 94 and prevent the flow in the opposite direction.

The check valve 120 has a valve seat 122 made of rubber or the like as shown in the drawing, and a movable valve body 124 biased toward the valve seat 122 by a spring 126. The strength of the spring 126 is such that when the hydraulic pressure on the conduit 94 side is a predetermined value from the hydraulic pressure on the upper liquid chamber 78 side, that is, when the flow rate corresponding to the peak flow rate flows, the upstream side and the downstream side of the orifice 52, that is, the flow rate. The strength is set so that the valve body 124 is opened only when the pressure difference between the channel 58 and the passage 58 is increased.

The check valve 130 has almost the same structure as the check valve 120, but the spring 136 that biases the valve body 134 toward the valve seat 132 is extremely weak as compared with the spring 126. In some embodiments, this spring 136 may be omitted.

In the excessive flow prevention device of the present embodiment configured as described above, the pressure on the upstream side of the orifice 52 is in the direction of opening the valve body 124 via the conduit 94 and in the direction of closing the valve body 134. Act on. The pressure on the downstream side of the orifice 52 is lowered through the communication flow path 57 formed in the flow rate limiting member 56, the cavity 60, and the plurality of through holes 92 provided in the bottom wall 84 of the lower housing member 68. To the upper liquid chamber 78 through the partition wall means 70 to close the valve body 124 and open the valve body 134. Therefore, when the flow rate does not reach the peak flow rate, both valves 120 and 130 are closed, the partition means does not move, and the area of the flow path 58 of the gate valve 54 is not limited at all. When the flow rate reaches the peak flow rate, a predetermined differential pressure is generated between the upstream side and the downstream side of the orifice 52, and the differential pressure acts on the valve element 124, so that the valve 120 opens and the upstream side pressure increases. The partition means 70 is moved downward by acting on the liquid chamber 78, and the flow restricting member 56 of the partition valve 54 restricts the area of the flow path 58 to a predetermined value, thereby restricting the flow rate from exceeding that value. When the flow rate decreases, the difference between the hydraulic pressures acting on both sides of the partition means 70 decreases, so that the partition means 70 is returned upward by the action of the return spring 90. At that time, the valve element 134 is opened to allow the liquid to flow from the upper liquid chamber 78 side to the conduit 94 side.

FIG. 5 shows an excessive flow prevention device according to a fourth embodiment of the present invention. This embodiment differs from the third embodiment in the position where the flow control device 150 is provided. Therefore, common members are given the same numbers and their explanations are omitted.

The flow control device 150 of the present embodiment has the same basic configuration as the flow control device 110 of the third embodiment and is provided with two check valves 151 and 152, but unlike the third embodiment, The fluid communication between the side liquid chamber 80 and the cavity 60, that is, the downstream side of the orifice 52 is controlled. That is, as shown, the check valves 151 and 152 are provided corresponding to the through holes 92 formed in the bottom wall 84 of the lower housing member 68.

That is, the check valve 151 shown in a simplified diagram in the figure corresponds to the check valve 120 of the third embodiment, allowing the flow from the lower liquid chamber 80 to the cavity 60, but not the reverse flow. Block. The spring used for the check valve 151 for urging the valve element toward the valve seat has a predetermined strength and a predetermined differential pressure between the lower liquid chamber 80 and the cavity 60. The valve 120 is opened only when the pressure is generated to allow the flow from the lower liquid chamber 80 toward the cavity 60.

On the other hand, the check valve 152 corresponds to the check valve 130 of the third embodiment, and allows the flow from the cavity 60 to the lower liquid chamber 80 but blocks the reverse flow. The spring that biases the valve body toward the valve seat is extremely weak or omitted.

In the present embodiment configured as described above, when the flow rate is less than or equal to the peak flow rate, the pressure upstream of the orifice 52 is passed through the conduit 94 to the upper liquid chamber 78 and further to the partition means 70. It acts on the lower liquid chamber 80 via. On the other hand, the pressure on the downstream side acts on the cavity 60 via the communication channel 57 of the flow rate limiting member 56. Both valves 151 and 152 are closed.

When the flow rate reaches the peak flow rate, a predetermined differential pressure is generated between the upstream side and the downstream side of the orifice 52, so that the valve 151 is opened. Therefore, water flows from the lower liquid chamber 80 to the cavity 60, the partition means 70 moves downward, the flow rate limiting member 56 limits the area of the flow path 58 to a predetermined value, and the flow rate further increases. To prevent. Then, when the flow rate decreases, the valve 152 opens.

[0029]

[Effect of the device]

 As described above, in the present invention, the differential pressure generated on both sides of the differential pressure generating device is used to displace the partition means arranged in the cylinder device, and the movement of the partition means causes the flow regulating device to move. Since the maximum permissible flow rate is set by interlocking with the flow rate limiting member, it is possible to provide an excessive flow rate preventer that is extremely structurally simple and inexpensive.

As the differential pressure generating device, it is possible to use a check valve, a water stop valve, a device such as a meter attached to the water pipe, and when using these existing devices, a new differential pressure generating device must be installed. No need to attach.

Any one of the upstream side and the downstream side of the differential pressure generating device and the communication with the corresponding liquid chamber are controlled using a flow control device, and the partition means is moved to a predetermined position only when a predetermined differential pressure is generated. If the flow rate is set to a lower level, the flow path is not limited at all when the flow rate is equal to or lower than the limit flow rate, and a more preferable outflow state of water is obtained.

Furthermore, if one of the communication means is branched from the flow path of the flow rate control device and acts on one of the liquid chambers, one of the conduits can be omitted and the cost can be further reduced. The laying work itself becomes simple.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a schematic configuration when an excessive flow prevention device according to an embodiment of the present invention is arranged in a water supply pipe to an apartment house.

FIG. 2 is a cross-sectional view showing the configuration of an excessive flow prevention device 10 of the first embodiment.

FIG. 3 is a cross-sectional view showing the configuration of an excessive flow prevention device 50 of a second embodiment.

FIG. 4 is a cross-sectional view showing the configuration of an excessive flow prevention device 100 of a third embodiment.

FIG. 5 is a sectional view showing the configuration of an excessive flow rate prevention device 140 of a fourth embodiment.

[Explanation of symbols]

 10, 50, 100, 140 Excessive flow rate preventing device 12, 52 Orifice (throttle device, differential pressure generating device) 14, 54 Gate valve (flow rate adjusting device) 15, 56 Flow rate limiting member 16, 64 Cylinder device 17, 70 Partition means 18, 20, 92 Conduit 22, 58 Flow path 30, 82 Stem (connecting member)

Claims (14)

[Scope of utility model registration request] 1. A water supply pipe is provided with a flow rate adjusting device capable of adjusting a flow rate in the water supply pipe, and when the flow rate in the water supplying pipe reaches a predetermined limit flow rate, the flow rate adjusting device is operated to operate the flow rate adjusting device. Limit the maximum flow rate in the water supply pipe to the above limit flow rate,
In an excessive flow prevention device for preventing a flow rate equal to or more than the limited flow rate, the flow rate adjusting device is provided in a flow path formed in the flow rate adjusting device and facing the flow path, A flow restricting member operable to adjust the flow passage area, wherein the excessive flow prevention device is a device installed in the water supply pipe in series with the flow adjusting device, wherein A differential pressure generating device that is configured to generate a pressure difference between the upstream side and the downstream side of the device according to the flow rate when passing, and the housing and the inside of the housing are divided into two liquid chambers, Any one of the two liquid chambers of the cylinder device including a cylinder device provided with a partition means that is displaceable in the housing due to a pressure difference between the two liquid chambers, and an upstream side and a downstream side of the differential pressure generating device, respectively. Crab fluid connection Passing means and said flow restrictor excessive flow prevention device, characterized in that a connecting member for interlocking the displacement of said partition wall means. 2. The excessive flow rate preventing device according to claim 1, wherein the communicating means is always in fluid communication with the corresponding liquid chambers on the upstream side and the downstream side of the differential pressure generating device, respectively. Over flow prevention device. 3. The excessive flow rate preventing device according to claim 1, wherein one of the communicating means is always in communication with a corresponding liquid chamber, and the other of the communicating means is the other communicating means and a liquid chamber corresponding thereto. It is possible to communicate with the corresponding liquid chamber through a flow control device that controls the opening and closing of the communication between the flow control device and the flow control device, and the flow control device has a predetermined value between the upstream side and the downstream side of the differential pressure generating device. Only when the above-mentioned differential pressure is generated, the movement of the partition wall means occurs in the direction in which the flow rate limiting member is moved in the direction in which the flow passage area is reduced, and the other communication means and its corresponding liquid. An excessive flow prevention device characterized by communicating with a chamber so that water flows. 4. The excessive flow rate preventing device according to claim 3, wherein the one communicating means communicates a downstream side of the differential pressure generating device with one of the liquid chambers, and the other communicating means has the differential pressure. The upstream side of the generator is connected to the other of the liquid chambers, and the flow control device includes two check valves arranged in parallel, and one of the check valves is connected to the other of the liquid chambers. The flow of water to the communication means of, and when the differential pressure of a predetermined value or more acts, allowing the flow of water from the other communication means to the other liquid chamber, the other of the check valve, An excessive flow rate preventing device, which allows a flow from the other liquid chamber to the other communicating means and prevents a flow of water from the other communicating means to the other liquid chamber. 5. The excessive flow rate preventing device according to claim 3, wherein the one communicating means communicates an upstream side of the differential pressure generating device with one of the liquid chambers, and the other communicating means uses the differential pressure. The downstream side of the generator is connected to the other of the liquid chambers, and the flow control device includes two check valves arranged in parallel, one of the check valves being connected from the other communication means to the other. Of the check valve to the liquid chamber, and when the differential pressure of a predetermined value or more acts, the flow of water from the other liquid chamber to the other communication means is allowed, and the other one of the check valves Is allowed to flow from the communicating means to the other liquid chamber and the flow of water from the other liquid chamber to the other communicating means is blocked. 6. The excessive flow prevention device according to claim 1, wherein the communication means is a conduit branching from the water supply pipe at a predetermined position of the water supply pipe and communicating with each of the liquid chambers. An excessive flow rate limiting device. 7. The excessive flow prevention device according to claim 1, wherein the cylinder device is mounted on the flow rate adjusting device via a hollow member, and the hollow member is provided in the flow path of the flow rate adjusting device. An excessive flow rate limiting device, wherein one of the communicating means includes the hollow member. 8. A flow control device for adjusting a flow rate in the water supply pipe is arranged in a water supply pipe of the water supply, and when the flow rate in the water supply pipe reaches a predetermined limit flow rate, the flow control device is operated to operate the flow control device. Limit the maximum flow rate in the water supply pipe to the above limit flow rate,
In an excessive flow prevention device for preventing a flow rate equal to or more than the limited flow rate, the flow rate adjusting device is provided in a flow path formed in the flow rate adjusting device and facing the flow path, The excessive flow prevention device further comprises a housing and two liquid chambers inside the housing, and the housing is formed by a pressure difference between the two liquid chambers. A cylinder device having a partition means displaceable therein, and a communication means capable of fluidly connecting two points separated in the flow direction of the water supply pipe to either one of the two chambers of the cylinder device. An excessive flow rate preventing device comprising a connecting member for interlocking the flow rate limiting member with the displacement of the partition means. 9. The excessive flow rate preventing device according to claim 8, wherein the communicating means is always in fluid communication with the corresponding liquid chambers on the upstream side and the downstream side of the differential pressure generating device. Over flow prevention device. 10. The excessive flow rate preventing device according to claim 8, wherein one of the communicating means is always in communication with a corresponding liquid chamber, and the other of the communicating means is the other communicating means and a liquid chamber corresponding thereto. It is possible to communicate with the corresponding liquid chamber through a flow control device that controls the opening and closing of the communication between the flow control device and the flow control device, and the flow control device has a predetermined value between the upstream side and the downstream side of the differential pressure generating device. Only when the above-mentioned differential pressure is generated, the movement of the partition wall means occurs in the direction in which the flow rate limiting member is moved in the direction in which the flow passage area is reduced, and the other communication means and its corresponding liquid. An excessive flow prevention device characterized by communicating with a chamber so that water flows. 11. The excessive flow rate preventing device according to claim 10, wherein the one communicating means communicates a downstream side of the differential pressure generating device with one of the liquid chambers, and the other communicating means has the differential pressure. The upstream side of the generator communicates with the other of the liquid chambers,
The flow control device includes two check valves arranged in parallel, and one of the check valves blocks a flow of water from the liquid chamber of the other to the communication means of the other, and a predetermined value or more. When the differential pressure is applied, the flow of water from the other communication means to the other liquid chamber is allowed, and the other one of the check valves allows the flow from the other liquid chamber to the other communication means. An excessive flow rate preventing device, which permits the flow of water from the other communicating means to the other liquid chamber. 12. The excessive flow rate preventing device according to claim 10, wherein the one communicating means communicates an upstream side of the differential pressure generating device with one of the liquid chambers, and the other communicating means uses the differential pressure. The downstream side of the generator communicates with the other of the liquid chambers,
The flow control device includes two check valves arranged in parallel, and one of the check valves blocks a flow from the communication means of the other to the liquid chamber of the other, and a difference of a predetermined value or more. When pressure is applied, the flow of water from the other liquid chamber to the other communication means is allowed, and the other of the check valves allows the flow from the other communication means to the other liquid chamber, An excessive flow rate preventing device, which blocks the flow of water from the other liquid chamber to the other communication means. 13. The excessive flow rate preventing device according to claim 8, wherein the communication means is a conduit branching from the water supply pipe at a predetermined position of the water supply pipe and communicating with each of the liquid chambers. An excessive flow rate limiting device. 14. The excessive flow prevention device according to claim 8, wherein the cylinder device is mounted on the flow rate adjusting device via a hollow member, and the hollow member is provided in the flow path of the flow rate adjusting device. An excessive flow rate limiting device, wherein one of the communicating means includes the hollow member.