JP2001108140A - Automatic valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic valve with a short recovery time to the closing position and the residual water discharge work time. SOLUTION: The automatic valve includes a cylinder device having a pressurization chamber for operating a valve element for opening and closing a valve seat, a pressure passage communicated with the pressurization chamber, a pressure discharge passage for discharging the pressure in the pressurization chamber to move a piston to the closing position, a flow limiting device provided in the pressure discharge passage, and a discharge device which is connected to the pressure discharge passage on the upstream of the flow limiting device and is capable of discharging back pressure substantially without a limit at the time of releasing. An atmospheric open valve communicating the pressure discharge passage with the atmospheric air may be connected to the uppermost part of the pressure discharge passage. The pressure passage may be provided with a flow limiting device. It is also possible to provide the atmospheric open valve right in close proximity to the secondary side of a starting valve of the pressure passage, and to provide the atmospheric open valve with an air pressurizing means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic valve, and more particularly to an automatic valve suitable for use in a watering system that operates when a fire occurs in a tunnel for road traffic or the like.

[0002]

2. Description of the Related Art In a tunnel disaster prevention system, a fire prevention section is set by dividing a longitudinal direction of a tunnel at a predetermined distance of, for example, 25 m, and water is sprayed on a predetermined area in a specific fire prevention section when a fire occurs. FIG. 5 schematically shows a conventional watering system for watering the inside of the tunnel. The watering system includes a pressurized water supply source such as a pump 2 for supplying fire-extinguishing water in a water storage tank 1 and a water supply source. Connected to the pressurized water supply and extended into the tunnel 3
A main pipe 4 for supplying pressurized water therein, and a plurality of branch pipes 5 connected to the main pipe 4 in the tunnel 3 are provided.

The main pipe 4 is buried in an inspection path 6 provided on the side of the subgrade in the tunnel 3 and extends along the tunnel 3 in a total of, for example, five sections (only two sections are shown in FIG. 5). ) Extends over a plurality of receiving compartments.

A required number of branch pipes 5 are provided in each receiving section. The branch pipes 5 rise from the main pipes 4 provided in the inspection path 6 along the side walls of the tunnel 3 and extend to near the ceiling of the tunnel 3. A head 7 for spraying pressurized water into a predetermined area in the tunnel 3 is connected to each of the distal end portions of these branch pipes 5.

At the root of the branch pipe 5, that is, at a low position,
A gate valve 8 and an automatic valve 10 provided downstream of the gate valve 8
And a pressure detector 11 connected to the upstream side and the downstream side with the automatic valve 10 interposed therebetween. The automatic valve 10 is opened when necessary, such as at the start of a fire or water discharge test, to supply pressurized water to the head 7 for watering, or closed at normal times, such as at the time of fire suppression or the end of the test, to stop supply of pressurized water to the head 7. It is to let. One example of such an automatic valve 10 is shown in FIG.

In FIG. 6, an automatic valve 10 includes a main body 14 divided into a primary chamber A and a secondary chamber B by a partition 13 having a valve seat 12, a main valve 15 for opening and closing the valve seat 12, and a main valve 15. It has a cylinder 18 having a piston 17 connected to the valve 15 and urged by a spring 16 therein, and a cylinder device 33 for opening and closing the main valve 15. The primary side (water supply side) of the automatic valve 10 is connected via a strainer 19 with a built-in stop valve, a pilot valve 20, a manual start valve 22, an exhaust valve 21 and a start circuit having an orifice 23 and a pressure switch 24, that is, a pressurized flow path 25, The piston 17 in the cylinder 18 communicates with an open space on the right side in FIG. Further, the same pressurizing circuit 25 is provided with the needle valve 2
6. a pressure regulating circuit having a pressure regulating valve 27, a strainer 28 and a pressure switch 29;
And the secondary side of the automatic valve 10.

When the pilot valve 20 of the pressurizing circuit 25 is opened at the position shown in FIG.
(Open side space), and a leftward force acts on the piston 17 in FIG. The pressure receiving area of the piston 17 is
The piston 17 moves leftward in FIG. 6 against the force of the spring 16 and the automatic valve 10 moves to the open position. When the pilot valve 20 is closed, the supply of pressure to the pressurizing chamber 34 (open side space) of the piston 17 is stopped, and the piston 17 is pushed rightward in FIG. The pressure in the pressurizing chamber (opening space) of the piston 17 is gradually released to the secondary side of the automatic valve 10 via the pressure adjusting circuit 30. The pressure adjustment circuit 30 includes the needle valve 26
When the pressure in the pressurizing chamber (open side space) is released, the flow rate is restricted, and the main valve 15 is closed so that the main valve 15 is closed suddenly and a water hammer phenomenon does not occur, thereby causing an inconvenience in the watering system. This is to make the operation slow. On the secondary side of the automatic valve 10, an automatic drain valve (a valve that closes when pressurized) 31 and a test water discharge valve 32 are also provided.

In FIG. 5, a pressure detector 11 is connected to each of the upstream and downstream branch pipes 5 with such an automatic valve 10 interposed therebetween. Can be measured upstream and downstream of the automatic valve 10. These two pressure gauges 11 are for checking the pressure regulating function of the automatic valve 10.

[0009] In such a watering system, it is necessary to periodically perform a water discharge test as to whether or not the function is maintained. At the time of the water discharge test, traffic control in the tunnel 3 is performed, and an appropriate water collecting device (not shown) is carried into the tunnel 3 so that the fire extinguishing water discharged to the water discharge head 7 is not scattered. Driving the watering system from. The flow rate of the fire extinguishing water collected by the water collecting device was measured to confirm that a predetermined amount of water was discharged.

At the end of the water discharge test, the automatic valve 10 is closed and the automatic drain valve 32 on the secondary side of the automatic valve 10 is opened to stop supplying water to the watering system and to drain the fire extinguishing water. Further, the water collecting device is removed from the water discharge head 7 and carried out of the tunnel 3 to release the traffic regulation. As a result of such a water discharge test, if predetermined watering is not performed, it is necessary to investigate the cause, and in the case of a malfunction of the device, it is necessary to remove and replace the device such as the automatic valve 10.

[0011]

In such a sprinkling system, when the water discharge test is completed, it is necessary to quickly return to the standby state. Main valve for 1
The closing operation of No. 5 was performed only slowly, and it took time to recover to the standby state. Therefore, it is desired that the automatic valve 10 can be closed immediately after the end of the water discharge test. Also,
It is necessary to close the automatic valve 10 immediately even when erroneous water discharge occurs for some reason.

At the end of the water discharge test, the automatic valve 10 is closed to stop water supply to the watering system, and the automatic valve 1
It is necessary that the drain valve 32 on the secondary side of 0 is opened and the fire extinguishing water is drained. However, in the fluid circuit around the main valve in the automatic valve, there is a portion having a small flow path cross-sectional area such as an orifice. Therefore, even if the drain valve 32 is opened, water is supplied to the orifice portion having a small flow path cross-sectional area. Because of the stagnation, it takes time to drain water from the automatic valve.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the conventional automatic valve for a watering system, to obtain an automatic valve which can be quickly restored, and to have a simple structure. The purpose of the present invention is to obtain an automatic valve for a watering system that can perform drainage work in a short time.

[0014]

According to the present invention, there is provided a main body having a primary chamber and a secondary chamber defined by a partition having a valve seat, and a valve for opening and closing the valve seat. Body, a piston connected to the valve body and a cylinder forming a pressurized chamber for slidably housing the piston and pressing the piston, a cylinder device for opening and closing the valve body, and a primary chamber of the main body. A pressurizing flow path that communicates with the pressurizing chamber of the cylinder device and pressurizes the piston in the cylinder to move the piston to the open position, and discharges back pressure from the pressurizing chamber of the cylinder device to stop pressurizing the piston Exhaust pressure passage that moves the piston in the cylinder to the closed position, a flow restriction device connected to the exhaust pressure flow passage for restricting and discharging the back pressure, and connected to the exhaust pressure flow passage upstream of the flow restriction device. Being released when back pressure Automatic valve and a discharge device capable of discharging without qualitatively limit is obtained.

The discharge device may include a branch pipe branched from the discharge pressure flow path and an openable / closable control valve connected to the branch pipe.

An air release valve connected to the uppermost part of the exhaust pressure passage and communicating the exhaust pressure passage with the atmosphere can be provided.

Further, according to the present invention, a main body having a primary chamber and a secondary chamber defined by a partition having a valve seat, a valve body for opening and closing the valve seat, a piston connected to the valve body, and this piston A cylinder device slidably housed therein, and a cylinder device for opening and closing the valve body, and a primary chamber of the main body communicating with a pressurizing chamber of the cylinder device, and pressurizing a piston in the cylinder to move the piston to an open position. A pressurizing flow path to be moved, an exhaust pressure flow path to discharge the back pressure of the pressurizing chamber of the cylinder device to stop the pressurization of the piston and move the piston in the cylinder to the closed position, and to be connected to the exhaust pressure flow path. An automatic valve having a flow rate restricting device for discharging while restricting the back pressure and an air release valve connected to the uppermost part of the exhaust pressure flow path and communicating the exhaust pressure flow path to the atmosphere can be obtained.

Further, a flow rate limiting device can be provided in each of the pressurizing flow path and the exhaust pressure flow path.

Further, the air release valve may be provided near the secondary side of the starting valve of the pressurized flow path.

Further, the air release valve may be provided with air pressurizing means.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a schematic view showing an embodiment of the automatic valve according to the present invention. In FIG. 1, an automatic valve 42 has the same structure as the automatic valve 10 shown in FIG. 6, and has a primary chamber A of a main body 14 and a pressurizing chamber 3 of a cylinder device 33 including a piston 17 and a cylinder 18.
4 and pressurizes the piston 17 in the cylinder 18 to move the piston 17 to the open position. Stop pressurizing and press the cylinder 18
Pressure passage 35 for moving piston 17 in the closed position
And a pressure regulating circuit, that is, a flow rate limiting device 30 connected to the exhaust pressure passage 35 and exhausting the piston back pressure to the secondary chamber B while limiting the piston back pressure.

The difference between the automatic valve 42 of the present invention and that shown in FIG. 6 is that, in addition to the elements described above, the automatic valve 42 is connected to the exhaust pressure passage 35 on the upstream side of the flow restricting device 30 so that the back pressure is reduced when the valve is opened. Discharge device 3 capable of discharging the wastewater with substantially no limitation
6 is provided.

In the example shown in FIG. 1, the discharge device 36 includes a branch pipe 37 branched from the discharge pressure passage 35, and a control valve 38 connected to the branch pipe 37 which can be opened and closed manually and opened to the outside.
And an emergency closing valve 39 connected in parallel to the control valve 38 and capable of being opened and closed by remote control. If necessary, an air release valve (not shown in FIG. 1), which will be described later with reference to FIG. It can also communicate.

During normal times of the watering system, the main valve of the automatic valve 10 of the watering system, ie, the main valve 15, is fully closed, the main valve limit switch (not shown) is on, and the water collecting device (not shown) is on standby. In the state, the water collecting device limit switch is off, the remote start valve 20 is closed, the remote test valve 22 is closed, and the main valve 1 is closed.
The secondary side of 5 has no pressure, the pressure switch 29 is off, and the automatic drain valve 31 is open.

In this state, when a fire occurs, the remote start valve (pilot valve) 20 is opened by remote start, the pressurizing chamber 34 is pressurized, the main valve 15 is opened, and the main valve limit switch is turned off. Then, the main valve is opened. As a result, flowing water is started, the secondary side of the valve 15 is pressurized, the pressure switch 29 is turned on, and a flowing water signal is issued. At this time, the automatic drain valve 31 is closed. Water is discharged from the head 7 by the start of flowing water, but water is discharged at a predetermined pressure because the secondary side is regulated.

When the watering system is to be restored for extinguishing a fire, the remote start valve (pilot valve) 20 is closed by a remote stop signal. Then, the pressure in the pressurizing chamber 34 is reduced, and the main valve 15 is gradually moved to the closed position by the quick closing prevention function of the pressure adjusting circuit 30, the pressure on the secondary side of the main valve 15 is reduced. The signal stops. At this time, the water discharge from the head 7 also stops, and the main valve 15
Is completely closed, the main valve limit switch is turned on, the automatic drain valve 31 is open, residual water is discharged from the main valve 15, and the running water stop operation is completed.

At the time of the test, a remote test valve (not shown) for starting the water collecting device is opened by starting the remote test,
After moving the water collecting device to the water collecting position and confirming normal operation with the water collecting device limit switch (not shown), when it is determined that the water discharge test preparation is completed, the remote starting operation is started and the remote starting valve is started. (Pilot valve) 20 is opened. When the water collecting device is not in the normal position, the water collecting device limit switch does not turn on, it is determined that the water discharge test preparation is not completed, so that the water collecting device can be checked and placed in the required appropriate position. Take appropriate measures.

When the remote start valve 20 is opened, the pressurizing chamber 34 is pressurized, the main valve 15 is opened, the main valve limit switch is turned off, and the main valve 15 is opened. If the limit switch is not turned off, there is a possibility that the starting valve 22 or the like has an abnormality, and these are confirmed and necessary measures are taken. When the main valve 15 is normally opened, the flowing water is started, the secondary side B of the main valve 15 is pressurized, the pressure switch 29 is turned on, and a flowing water signal is issued. When the pressure switch 29 is not turned on, it is checked whether there is any abnormality in the pressure switch or the like, and necessary measures are taken so that a running water signal is issued. At this time, automatic drain valve 2
0 is closed. Water is discharged from the head 7 by the start of flowing water, but water is discharged at a predetermined pressure because the pressure is regulated on the secondary side.

When the watering system is to be restored after the water discharge test, the remote start valve (pilot valve) 20 is closed by the remote stop signal. Then, the pressure in the pressurizing chamber 34 is reduced, and the main valve 15 is gradually moved to the closed position by the quick closing prevention function of the pressure adjusting circuit 30, so that the secondary side of the main valve 15 is depressurized.
The pressure switch 25 is turned off, and the running water signal stops.
If the pressure switch 25 is not turned off, it is determined that there is an abnormality, and the pressure switch 25 and the main valve 15 are checked, necessary measures are taken, and the pressure switch 25 is turned off to stop the flowing water signal. At this time, the water discharge from the head 7 also stops, and when the main valve 15 is completely closed, the main valve limit switch is turned on, and the automatic drain valve 31 is open and the main valve 1 is closed.
5 discharges residual water, completes the running water stop operation, and
5 is restored. When the main valve limit switch does not turn on, it is necessary to check the main valve 15 and the like and to restore the main valve 15.

As described above, when the residual water is completely discharged from the automatic valve 42 after the end of the water discharge test, the automatic valve 42 of the present invention allows the discharge device 36 to be opened. When the discharge device 36 is opened, the discharge pressure of the pressurizing chamber 34 by the piston 17 enters the branch pipe 37 from the discharge pressure passage 35 without being subjected to the flow restriction operation by the flow restriction device 30, and passes through the control valve 38 to the outside. Since the water is drained, the back pressure can be discharged substantially without restriction. Therefore, the automatic valve 42 can be closed quickly. Further, even when erroneous water discharge occurs due to some cause, the automatic valve 42 can be immediately closed by opening the discharge device 36 in the same manner. Such a branch pipe 37 may branch from any position as long as the pressure in the pressurizing chamber 34 is released, and the automatic valve 42
In this configuration, a connection from the orifice 23 to the pressure regulating valve 27 and the pressurizing chamber 34 can be established.

Next, when the remote test stop signal is supplied to close the remote test valve 32 in order to restore the water collecting device, the water collecting device (not shown) returns to a predetermined recovery position, and the water collecting device is restored. The limit switch is turned on and the recovery of the water collecting device is confirmed. At this time, if the water collecting device limit switch does not turn on, the abnormality of the water collecting device is confirmed, and necessary measures are taken so that the water collecting device turns on. Complete restoration of the whole watering system is completed by restoration of the water collecting device.

Embodiment 2 The automatic valve 43 of the present invention shown in FIG.
0 is provided. This air release valve 40 is connected to the exhaust pressure passage 35.
(Not shown in FIG. 2 to clarify the relation with other embodiments), and along the flow path of the residual water when the residual water of the automatic valve 43 is discharged. Look,
It is provided upstream of the orifice 23, which is a means for restricting the flow rate. The atmosphere release valve 40 is provided near the secondary side of the start valve (pilot valve) 20 of the pressurized flow path 25.

The orifice 23 is a portion having a very small cross-sectional area of the flow passage, and the flow rate of the residual water is limited at this portion, and the flow of the residual water is extremely poor particularly at the time of drainage with a small pressure difference. However, when the air release valve 40 is opened upstream of the orifice 23 when the water discharge test is completed or after the sprinkling system is operated, air is introduced from the air release valve 40 and the flow of the residual water is smoothly performed. In particular, after the liquid level of the residual water passes through the orifice 23, since only air flows through the orifice 23, the flow rate of the residual water is not substantially restricted,
Residual water drains quickly.

FIG. 3 shows the air release valve 40 of the embodiment shown in FIG.
3 is a schematic diagram showing the relationship between the height position of the main valve 15, the pressurizing flow path 25, and the exhaust pressure flow path 35, and the functional relation of each element is the same as FIG. It is understood from FIG. 3 that the atmosphere release valve 40 of the present invention is connected to the uppermost part of the exhaust pressure passage 35 including the pressurization passage 25. The pressurizing flow path 25 is provided with an orifice 23,
Since the pressure regulating valve 30 is provided in 5, it is understood that a flow rate limiting device is provided in each of the pressurizing flow path 25 and the exhaust pressure flow path 35. The air release valve 40 is provided near the secondary side of the starting valve 20 of the pressurizing flow path 25 also here.

Embodiment 3 FIG. In the embodiment shown in FIG. 4, an air pressurizing means 41 is connected to an atmosphere release valve 40 provided at the highest position of the pressurizing and discharging channels 25 and 35. The air pressurizing means 41 is a compressor that compresses air and sends it into the flow path in the illustrated example. In addition to opening the air release valve 40 to release air, if compressed air is actively supplied to drain residual water, the operation of draining residual water from the automatic valve can be completed in a shorter time. At this time, if the pressurization by the compressor is too high, the valve will open, so it is necessary to feed the pressurized pressure.

[0036]

As described above, the automatic valve of the present invention is connected to a main body having a primary chamber and a secondary chamber defined by a partition having a valve seat, a valve element for opening and closing the valve seat, and a valve element. And a cylinder device for slidably receiving the piston and forming a pressurizing chamber for pressing the piston, and a cylinder device for opening and closing the valve body and a primary chamber of the main body communicating with the pressurizing chamber of the cylinder device. Pressurizing the piston in the cylinder to move the piston to the open position, and discharging the back pressure in the pressurizing chamber of the cylinder device to stop pressurizing the piston and close the piston in the cylinder. A drain pressure passage to be moved to the drain pressure passage, a flow restricting device connected to the drain pressure passage for discharging while restricting the back pressure, and a drain pressure passage connected upstream of the flow restricting device to reduce the back pressure when opened. Can be discharged with virtually no restrictions And a discharge device capable of.
Therefore, even at the end of the water discharge test or when erroneous water discharge occurs for some reason, the closing operation of the main valve is performed promptly and it takes time to recover to the standby state, regardless of the flow rate restriction action by the pressure adjustment circuit. Since there is no water discharge test, the automatic valve can be closed immediately after the discharge test.

Further, the discharge device can be provided with a branch pipe branched from the discharge pressure passage and an openable and closable control valve connected to the branch pipe. The present invention can be implemented, and the present invention can be easily applied to an existing automatic valve already installed on the site.

Further, since it is possible to provide an air release valve which is connected to the uppermost part of the exhaust pressure passage and communicates the exhaust pressure passage to the atmosphere, not only the return of the automatic valve to the closed position but also the automatic release The residual water discharge work of the valve can also be performed quickly.

Further, according to the present invention, a main body having a primary chamber and a secondary chamber defined by a partition having a valve seat, a valve body for opening and closing the valve seat, a piston connected to the valve body, and this piston A cylinder device slidably housed therein, and a cylinder device for opening and closing the valve body, and a primary chamber of the main body communicating with a pressurizing chamber of the cylinder device, and pressurizing a piston in the cylinder to move the piston to an open position. A pressurizing flow path for moving, a discharge pressure flow path for discharging pressure of the pressurizing chamber of the cylinder device to stop pressurizing the piston and move the piston in the cylinder to the closed position, An automatic valve having a flow restricting device for discharging while restricting the pressure, and an air release valve connected to the uppermost portion of the exhaust pressure passage and communicating the exhaust pressure passage to the atmosphere is obtained. Therefore, when the residual water is discharged from the automatic valve and restored after the water discharge test or the operation of the sprinkling system, if the air release valve is opened, the air is introduced from the atmospheric release valve and the flow of the residual water becomes smooth. As a result, the flow rate of the residual water is not substantially reduced, and the residual water is quickly discharged.

Further, since a flow restricting device can be provided in each of the pressurizing flow path and the exhaust pressure flow path, the automatic closing operation of the automatic valve can be more reliably slowed down, and various devices in the flow path are caused by the water hammer phenomenon. Can be prevented from being damaged.

Further, since the atmosphere release valve can be provided in the vicinity of the secondary side of the starting valve of the pressurized flow path, the time in which the fire extinguishing water has to pass through the orifice serving as the flow rate restricting means is shortened, and the residual water is reduced. The discharge operation time can be shortened.

Further, since the air release valve may be provided with an air pressurizing means, not only the air release valve is opened to simply release the air, but also the compressed air is actively supplied to drain the residual water. As a result, the operation time of the residual water drainage of the automatic valve can be further reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an automatic valve of the present invention.

FIG. 2 is a schematic sectional view showing another embodiment of the automatic valve of the present invention.

FIG. 3 is a schematic diagram showing a height positional relationship of the automatic valve shown in FIG. 2;

FIG. 4 is a schematic sectional view showing another embodiment of the automatic valve of the present invention.

FIG. 5 is a schematic diagram showing a watering system to which the automatic valve of the present invention can be applied.

FIG. 6 is a schematic sectional view showing an example of a conventional automatic valve.

[Explanation of symbols]

12 valve seat, 13 partition, A primary chamber, B secondary chamber, 1
4 Main body, 15 valve body, 17 piston, 18 cylinder, 25 pressurized flow path, 30 flow restriction device, 33 cylinder device, 34 pressurized chamber, 35 discharge pressure flow path, 36 discharge device, 37 branch pipe, 38 control valve, 40 Air release valve, 41 Air pressurizing means, 42, 43, 44 Automatic valve.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) F16K 31/363 F16K 31/363 F-term (Reference) 2E189 EA01 MB01 MB06 3H056 AA01 BB02 BB24 CA02 CA06 CB03 CB05 CC03 CC11 CD06 DD02 DD03 EE08 GG05 3H060 AA02 CC14 CC33 CC40 DA04 DC10 DD05 DD12 DF03 HH03 HH25

Claims (7)

[Claims] 1. A main body having a primary chamber and a secondary chamber defined by a partition having a valve seat, a valve body for opening and closing the valve seat, a piston connected to the valve body, and a slidable piston. A cylinder device that forms a pressurized chamber that presses a piston by being housed in the cylinder device, and a cylinder device that opens and closes the valve element; and communicates the primary chamber of the main body with the pressurized chamber of the cylinder device, A pressurizing flow path that pressurizes a piston to move the piston to an open position; and discharges back pressure of a pressurizing chamber of the cylinder device to stop pressurizing the piston and move the piston in the cylinder to a closed position. An exhaust pressure flow path to be moved; a flow restricting device connected to the exhaust pressure flow path for discharging while limiting the back pressure; and The back pressure And a discharge device capable of discharging the liquid with substantially no restriction. 2. The automatic valve according to claim 1, wherein the discharge device includes a branch pipe branched from the discharge pressure flow path, and an openable / closable control valve connected to the branch pipe. 3. The automatic valve according to claim 1, further comprising an air release valve connected to an uppermost portion of the exhaust pressure passage and communicating the exhaust pressure passage to the atmosphere. 4. A main body having a primary chamber and a secondary chamber defined by a partition having a valve seat, a valve body for opening and closing the valve seat, a piston connected to the valve body, and a slidable piston. A cylinder device for driving the valve body to open and close, and a primary chamber of the main body communicating with a pressurizing chamber of the cylinder device, and pressurizing a piston in the cylinder to move the piston to an open position. A pressurizing flow path for moving; a discharging pressure flow path for discharging back pressure of a pressurizing chamber of the cylinder device to stop pressurizing the piston to move a piston in the cylinder to a closed position; An automatic valve, comprising: a flow restricting device connected to the exhaust port for restricting and discharging the back pressure; and an air release valve connected to an uppermost portion of the exhaust pressure flow path and communicating the exhaust pressure flow path to the atmosphere. 5. The automatic valve according to claim 4, wherein a flow rate limiting device is provided in each of the pressurizing flow path and the exhaust pressure flow path. 6. The automatic valve according to claim 4, wherein the air release valve is provided near a secondary side of a start valve of the pressurized flow path. 7. The automatic valve according to claim 4, wherein an air pressurizing means is provided in the atmosphere release valve.