JP2001124234A - Automatic valve and automatic selection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic valve capable of correctly regulating the pressure of the fire extinguishing water by correctly monitoring the secondary pressure, and preventing a water hammer phenomenon caused by closing a main valve. SOLUTION: The automatic valve comprises a cylinder device having a pressure chamber to operate a valve element to open/close a valve seat, a pressure flow passage communicated with the pressure chamber, a pressure discharge passage to discharge the pressure in the pressure chamber to shift a piston to the closing position, and a flow rate control device provided on the pressure discharge flow passage to regulate the flow rate according to the pressure in a secondary pipe connected to a secondary chamber of the main valve. The flow rate control device is provided with a monitored pressure switching valve which can be selectively switched between a first monitoring pipe communicated with the secondary pipe connected to a body and a second monitoring pipe communicated with the secondary chamber of the body. An opening of the discharge pressure flow passage is covered by the piston close to the closing position with a predetermined gap therein, and provided at the position to give the predetermined flow passage resistance.

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 which operates when a fire occurs in a tunnel for road traffic or the like, and an automatic selection valve suitable for use in the automatic valve. Things.

[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. 17 schematically shows a conventional watering system for watering the inside of a 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 pressurized water supply source. Tunnel 3 connected to the source and extending into 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 along the tunnel 3, for example, five sections as a whole (only two sections are shown in FIG. 17). ) Extends over a plurality of receiving compartments.

A required number of branch pipes 5 are provided in each receiving section, and the main pipes 4 provided in the inspection path 6 are provided.
And rises along the side wall of the tunnel 3 to near the ceiling of the tunnel 3. Each of the branch pipes 5 has a water discharge head for spraying pressurized water into a predetermined area in the tunnel 3. 7 is connected.

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 to supply pressurized water to the water discharge head 7 for spraying when necessary, such as at the start of a fire or a water discharge test, or closed to supply pressurized water to the water discharge head 7 at the time of fire suppression or the end of a test. Is to stop. One example of such an automatic valve 10 is shown in FIG.

In FIG. 18, an automatic valve 10 has a primary chamber A formed by a partition 13 having a valve opening around which a valve seat 12 is formed.
A main body 14 divided into a secondary chamber B, a main valve 15 for opening and closing a valve opening, and a cylinder 18 having a piston 17 connected to the main valve 15 and urged by a spring 16 therein.
A cylinder device 33 for opening and closing the main valve 15. The primary chamber A (water supply side) of the automatic valve 10 includes a strainer 19 with a built-in stop valve, a pilot valve 20, an exhaust valve 21,
Through a starting circuit having a manual starting valve 22 and an orifice 23, that is, a pressurizing flow path 25, the open space or pressurizing chamber 3 on the right side in FIG.
It communicates with 4. Further, the same pressurizing flow path 25 is connected to a pressure adjusting device 3 having a needle valve 26 and a pressure adjusting valve 27.
It communicates with the secondary chamber B of the automatic valve 10 through a pressure adjustment circuit provided with a zero or a pressure relief flow path 35.

When the pilot valve 20 of the pressurizing flow path 25 is opened at the position shown in FIG. 18, the primary pressure is gradually introduced into the pressurizing chamber 34 (opening space) of the cylinder 18 through the orifice 23 and In FIG. 18, a leftward force acts.
Since the pressure receiving area of the piston 17 is larger than the pressure receiving area of the main valve 15 and the pressure is the same, the piston 17 moves leftward in FIG. 18 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 (opening space) of the piston 17 is stopped, and the piston 17 is pushed rightward in FIG.
5 is moved to the closed position, and the pressurizing chamber 34 of the piston 17 is moved.
The pressure in the (open side space) is gradually released to the secondary side of the automatic valve 10 via the pressure adjusting device 30. When the pressure in the pressure chamber 34 (opening space) is released, the pressure regulating circuit, that is, the exhaust pressure passage 35, restricts the flow rate by the needle valve 26, the valve 15 is closed rapidly, and a water hammer phenomenon occurs to spray water. This is to make the closing operation of the main valve 15 slow so that no inconvenience occurs in the system. On the secondary side of the automatic valve 10, an automatic drain valve 31 and a test water discharge valve 32 are also provided.

In FIG. 17, a pressure detector 11 is connected to each of the upstream and downstream branch pipes 5 with such an automatic valve 10 interposed therebetween, and the pressure of the pressurized water flowing through the branch pipe 5 is increased. Can be measured upstream and downstream of the automatic valve 10. These two pressure gauges 11 are for confirming the pressure adjusting function of the automatic valve 10 from the reading.

[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. In the water discharge test, the water discharge head 7
The water spray condition was checked visually by visual observation. However, in recent years, at the time of the water discharge test, traffic control in the tunnel 3 was performed, and an appropriate water collecting device (not shown) was installed in the tunnel 3.
The fire extinguishing water that was carried into the water discharge head 7 and discharged was prevented from being scattered, and then by operating the water spraying system, the flow rate of the fire extinguishing water collected by the water collecting device was measured, and the predetermined water discharge amount was determined. It was confirmed that it had been released.

At the end of the water discharge test, the automatic valve 10 is closed to stop supplying water to the water discharge head 7, and the automatic drain valve 31 on the secondary side of the automatic valve 10 is opened 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 the automatic valve used in such a watering system, a pressure regulating valve 27 is connected to a secondary chamber B of the main valve 15 via a monitoring pipe to connect the secondary chamber B to the secondary chamber B. The pressure is monitored, and the pressure of the fire extinguishing water supplied by the automatic valve 10 is adjusted to be constant. The pressure in the secondary chamber B is not uniform when viewed in detail, and varies depending on the position in the secondary chamber B. For example, at a position close to the partition wall 13 or the valve seat 12, a flow stagnation occurs depending on the magnitude of the flow rate. As a result, the pressure in the secondary chamber B may not always be accurately monitored, and an error may occur in the pressure adjustment.

Further, the pressure regulating circuit 35 restricts the flow rate so as to gradually release the pressure of the pressurizing chamber (open side space) 34, the valve 15 closes suddenly, a water hammer phenomenon occurs, and the water sprinkling system Although the closing operation of the main valve 15 is made slow so as not to cause any inconvenience, it is also desired that the automatic valve be restored as quickly as possible.

Furthermore, if the fire extinguishing water can be supplied to the secondary side or the secondary side pipe 5 connected to the automatic valve 10 during the function test of the automatic valve, the secondary side pipe can be installed in the factory. The test can be performed without using water, and when installed in the watering system of a building or equipment, fire water is not discharged from the water discharge head, so the surroundings will be flooded and there will be difficulty in treating fire water. Not even. Therefore, the test of the automatic valve 10 alone without connecting the secondary pipe 5b to the automatic valve 10 can be performed, or the test can be performed with the secondary pipe 5b connected and incorporated in the watering system if necessary. It is desired to develop an automatic valve 10 that can also be used. It would be extremely convenient if such automatic valve connection switching could be performed automatically rather than manually.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the conventional automatic valve, and to provide an automatic valve capable of accurately monitoring the secondary pressure of the main valve and accurately adjusting the pressure of the extinguishing water to be supplied. It is also to provide an automatic valve that prevents the water hammer phenomenon due to the closing operation of the main valve, and it is also possible to test only the automatic valve without connecting the secondary pipe to the automatic valve It is also to provide an automatic valve that can perform a function test with the secondary pipe connected to the sprinkling system if necessary and installed in the sprinkling system. An object of the present invention is to provide an automatic selection valve which can be automatically operated.

[0015]

According to the present invention, there is provided an automatic valve comprising: a main body having a primary chamber and a secondary chamber defined by a partition having a valve opening;
A first valve body that opens and closes the valve opening from the primary chamber side, a piston connected to the valve body, and a cylinder that slidably accommodates the piston and forms a pressurized chamber that presses the piston; A cylinder device to be opened and closed, a primary chamber of the main body communicating with a pressurizing chamber of the cylinder device, a pressurizing flow path for pressurizing a piston in the cylinder and moving the piston to an open position, and a pressure of the pressurizing chamber of the cylinder device. And a flow-restriction device connected to the discharge-pressure flow passage for restricting the back pressure of the piston and discharging the exhaust gas while stopping the pressurization of the piston and moving the piston in the cylinder to the closed position. The flow restricting device is an automatic valve whose flow rate is adjusted in accordance with the pressure in the secondary pipe connected to the secondary chamber of the main body.

Further, the flow restricting device can selectively switch between a first monitoring pipe communicating with a secondary pipe connected to the main body and a second monitoring pipe communicating with a secondary chamber of the main body. With a simple monitoring pressure switching valve.

Further, the opening of the exhaust pressure passage communicating with the pressurizing chamber is provided at a position at least partially covered by the piston when the piston is near the closed position.

Further, the automatic valve according to the present invention includes 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, a piston connected to the valve element, and a piston. Equipped with a cylinder that slidably accommodates a piston, a cylinder device that opens and closes the valve, and a primary chamber of the main body that communicates with the pressurizing chamber of the cylinder device, pressurizes the piston in the cylinder to open the piston. A pressurizing flow path for moving, a discharging pressure flow path for discharging the 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, and a piston connected to the discharging pressure flow path A flow restricting device for discharging while limiting the back pressure of the piston, wherein the opening of the exhaust pressure passage communicating with the pressurizing chamber is at a position at least partially covered by the piston when the piston is near the closed position. It is what was kicked.

Further, at a position where the outer peripheral wall of the piston covers at least the opening of the exhaust pressure passage, the piston is separated from the cylinder wall with a predetermined gap to provide a predetermined flow resistance. .

Further, the piston has a small-diameter portion in the circumferential direction in a crown portion of the piston.

Further, the automatic valve according to the present invention has a main body having a primary chamber and a secondary chamber defined by a partition having a valve opening, a first valve body for opening and closing the valve opening from the primary chamber side, A first cylinder device that opens and closes a valve body, comprising a piston connected to a valve body and a cylinder that slidably accommodates the piston and forms a pressurization chamber that presses the piston, and the primary chamber of the main body. A first pressurizing flow path that communicates with the pressurizing chamber of the first cylinder device to pressurize the piston in the cylinder and move the piston to the open position; A first exhaust pressure passage for stopping the pressurization and moving the piston in the cylinder to the closed position; and a first exhaust pressure passage connected to the first exhaust pressure passage for adjusting a flow rate according to the pressure of the secondary chamber of the main body, and Flow control to discharge while limiting pressure A second valve body that opens and closes the valve opening from the secondary chamber side, a second piston connected to the second valve body, and a pressurizing unit that slidably accommodates the second piston and presses the second piston. A second cylinder device that has a cylinder that forms a pressure chamber and drives the second valve body to open and close; and a primary chamber of the main body that communicates with a second pressure chamber of the second cylinder device. A second pressure passage for pressurizing the piston to move the second piston to the open position;
A second exhaust pressure passage for discharging the pressure of the pressurizing chamber to stop pressurizing the second piston and moving the second piston in the second cylinder to the closed position, a flow restricting device, a secondary chamber of the main body, and When the first valve body is in the open position and the second valve body is in the open position, the flow restricting device is connected to the secondary chamber of the main body, and the first valve body is connected to the exhaust pressure chamber of the second cylinder device. When the second valve body is in the open position and the second valve body is in the closed position, there is provided a selection valve for communicating the flow rate restriction device with the exhaust pressure chamber of the second cylinder device.

Further, the selection valve may be an automatic valve for selectively connecting the flow restricting device to the higher one of the secondary chamber of the main body and the exhaust pressure chamber of the second cylinder device.

Further, the automatic selection valve of the present invention has a hollow columnar main body, first and second valve openings respectively provided at both ends in the axial direction of the main body at predetermined distances and each having a valve seat, And a piston slidably provided in the body to partition a space in the body into a first chamber and a second chamber; and a piston provided in the body so as to communicate with the first and second chambers defined by the piston. The first input opening and the second input opening are connected to both sides of the piston in the axial direction, and are provided between the first and second valve openings and spaced apart by a distance smaller than a predetermined distance of the valve openings. And first and second valve bodies selectively opening and closing the first and second valve openings, and an output opening communicating with both the first and second valve openings. .

The first and second valve openings may have valve seats on the secondary chamber side, and the first and second valve bodies connected to the piston may be provided in the secondary chamber.

Further, first and second springs having a predetermined stroke may be provided between the piston and the first and second valve bodies.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a schematic view showing an embodiment of the automatic valve 42 of the present invention. In FIG. 1, the automatic valve 42 has the same structure as the automatic valve 10 shown in FIG.
6. The piston 17 in the cylinder 18 is pressed to the open position by communicating with the pressurizing chamber 34 of the cylinder device 33 composed of the piston 17 and the cylinder 18 and utilizing the primary pressure supplied to the primary pipe 5a. The pressure in the pressurizing flow path 25, which is a starting circuit for moving, and the pressure in the pressurizing chamber 34 of the cylinder device 33 are discharged to stop pressurizing the piston 17, and the cylinder 1
Exhaust pressure passage 35 for moving piston 17 in 8 to the closed position
And a flow control device 30 connected to the discharge pressure passage 35 for discharging to the secondary chamber B while limiting the piston back pressure.

The automatic valve 42 of the present invention is different from that of FIG. 18 in that the pressurizing chamber 34 of the cylinder device 33 is connected to the regulator type pressure regulating valve 27 via the closing time regulating needle valve 26, that is, the flow regulating device. 30 and that the flow rate adjusting device 30 can adjust the flow rate according to the pressure in the secondary pipe 5b connected to the secondary chamber B of the main valve 15. That is, in the illustrated example, the monitoring pipe from the flow control device 30 is connected to the selectively switchable monitoring pressure switching valve 44 and communicates with the secondary pipe 5b connected to the main valve 15. It is configured to be selectively switchable between a first monitoring pipe 45 and a second monitoring pipe 46 communicating with the secondary chamber B of the main body 14.

In the example shown in FIG. 1, the first monitoring pipe 45 connected to the monitoring pressure switching valve 44 is connected not to the automatic valve body 14 but to the secondary pipe 5b connected to the automatic valve 42 through the strainer 47. The second monitoring pipe 46 is connected to the secondary chamber B of the main body 14 at a position relatively close to the valve seat 12 or the partition 13 via the strainer 28.

FIG. 1 shows a state of the automatic valve 42 according to the present invention at the time of fire monitoring. The valve 15 is fully closed, the remote start valve 20 is closed,
The manual start valve 22 is closed and the automatic drain valve 31 is open. The monitoring pressure switching valve 44 communicates with the first monitoring pipe 45 and the flow control device 30, and the second monitoring pipe 46 and the flow control device 3
0 is in the position where it was cut off.

FIG. 2 shows a state when a fire occurs in this state. The remote start valve (pilot valve) 20 is opened by the remote start, and the pressurizing chamber 34 is
Is pressurized, the main valve 15 is opened, and flowing water is started.
The secondary chamber B of No. 5 is pressurized. The water is discharged from the head 7 by the start of the flowing water. However, since the pressure is adjusted based on the pressure in the pipe 5 instead of the pressure in the secondary chamber B, the water is discharged at an accurate predetermined pressure.

When the watering system is restored for fire suppression, 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 function of preventing rapid closing of the needle valve 26, and the secondary side of the main valve 15 is reduced in pressure. At this time, the automatic drain valve 31 is open, the residual water is discharged from the secondary chamber B, the discharge of water from the head 7 is also stopped, and the running water stop operation is completed when the main valve 15 is completely closed.

FIG. 3 shows a state of the automatic valve 42 during a test. FIG. 3 shows a water discharge test in a state where the automatic valve is connected to the pipe 5b and incorporated in the watering system. The automatic valve 42 of the present invention monitors the pressure in the secondary chamber B by the second monitoring pipe 46. Therefore, the inspection at the factory can be performed without preparing the secondary side pipe 5 and connecting it to the automatic valve 42. In this case, the test water control valve 49 is closed, the test water discharge valve 32 is opened, and the manual activation valve 22 is opened.
Is opened, the pressurizing chamber 34 is pressurized, the main valve 15 is opened, and the flowing water is started. The fire extinguishing water flowing from the primary chamber A to the secondary chamber B of the main valve 15 is discharged from the test water discharge valve 32 to the outside.
Since the pressure of the flowing water is supplied from the second monitoring pipe 46 connected to the secondary chamber B to the pressure regulator 30 via the monitoring pressure switching valve 44, the valve opening is adjusted by the secondary pressure,
It can be confirmed that water is discharged at a predetermined pressure.

A water discharge test in a state where the automatic valve 42 is connected to the branch pipe 5 and incorporated in a watering system can of course be performed. In this case, the test water control valve 49 is opened, and the monitoring pressure switching valve 44 is opened.
By operating the first monitoring pipe 45 to the pressure regulator 30 to close the second monitoring pipe 46 and closing the test water discharge valve 32, the pressure in the secondary pipe 5b can be used for pressure adjustment. .

When the watering system is to be restored after the water discharge test, the manual start valve 22 is closed. Then pressurizing chamber 3
4, the valve 15 is gradually moved to the closed position by the function of preventing rapid closing of the needle valve 26, the pressure on the secondary side of the valve 15 is reduced, and the flow signal stops. At this time, the automatic drain valve 31 is open, the residual water is discharged from the main body 14, the discharge of water from the head 7 is also stopped, and when the main valve 15 is completely closed, the running water stop operation is completed and the main valve 15 is restored. I do.

Embodiment 2 FIG. 4 shows the details of the structure of the cylinder device 33 of the automatic valve 42 of the present invention shown in FIGS. 1 to 3, in particular, the opening 48 of the exhaust pressure passage 35 communicating with the pressurizing chamber 34 of the cylinder, the piston 17, and the like. Is shown. (Note that the opening 48 is also an opening of the pressurizing circuit 25.) That is, in the automatic valve 42, the exhaust pressure passage 35
The opening 48 of the main body 14 of the automatic valve 42 and the cylinder device 18
The opening 48 is directly open to the pressurizing chamber 34 even when the piston 17 is in the closed position as shown in FIG. Therefore,
When the automatic valve 42 is closed, the fire extinguishing water in the pressurizing chamber 34 is pushed out through the opening 48 by the movement of the piston 17. At this time, the resistance acting on the fire extinguishing water entering the opening 48 does not change. Therefore, when the piston 17, that is, the main valve 15 is closed, when the flow rate restriction device is not provided in the exhaust pressure circuit 35,
The main valve 15 closes rapidly and a water hammer phenomenon occurs.

The automatic valve 52 of the present invention shown in FIGS.
In order to solve this problem, the opening 50 of the exhaust pressure passage 35 communicating with the pressurizing chamber 34 is at least partially formed by the piston 17 when the piston 17 is near the closed position (FIG. 4). It is provided at a position to be covered. In the illustrated example, the opening 50 of the exhaust pressure passage 35 is connected to the main body 1 of the automatic valve 52.
When the piston 17 is located at a position that covers at least the opening 50 of the exhaust pressure passage 35, the outer peripheral wall 51 of the crown portion of the piston 17, that is, The outer peripheral wall 51 of the annular projection extending in the axial direction of the piston 17 is spaced apart from the inner wall of the cylinder 18 by a predetermined gap G in the radial direction, and a predetermined distance is set for the flow path reaching the opening 50 through the gap G. Is provided. Although not shown, a small circumferential portion such as an annular circumferential groove may be formed in the crown portion of the piston 17 and the predetermined gap G may be formed by the small diameter portion.

At the time of the closing operation of the automatic valve 52, the fire extinguishing water in the pressurizing chamber 34 is pushed out through the opening 50 by the movement of the piston 17 from the state shown in FIG. When the outer peripheral wall of the piston 17 reaches the opening 50, the opening 50 is covered with the predetermined gap G by the outer peripheral wall, and a flow path resistance is generated in the flow path from the pressurizing chamber 34 to the opening 50 in a state as shown in FIG. I do. Therefore, the subsequent movement of the piston 17 becomes slow, and even when the flow rate restricting device is not provided in the exhaust pressure passage 35, the occurrence of the water hammer phenomenon can be prevented.

Embodiment 3 7 to 12 show an automatic valve 60 according to another embodiment of the present invention.
Has a primary chamber A and a secondary chamber B defined by a partition 64 having a valve opening 63 that can be opened and closed from both sides by a first valve body 61 and a second valve body 62. FIG. 7 shows a normal state in which the first valve body 61 of the automatic valve 60 is closed and the second valve body 62 is open. FIG. 8 shows that the first valve body 61 and the second valve body 62 of the automatic valve 60 are closed. FIG. 9 shows a state in which both of the first valve body 61 and the second valve body 62 of the automatic valve 60 are closed (when the head is in a non-head water discharge state).
FIG. 10 shows a state where the first valve body 61 of the automatic valve 60 is open and the second valve body 62 is closed (during non-head water discharge).
FIG. 11 and 13 show an automatic selection valve 66 that can be used for the automatic valve 60 of the present invention.

The automatic valve 60 shown in FIGS. 7 to 10 has valve seats formed on both sides and can be opened and closed from both sides.
A main body 65 having a primary chamber A and a secondary chamber B partitioned by a partition 64 having a first valve body 61 for opening and closing the valve opening 63 from the primary chamber A side, and a valve opening 63 from the secondary chamber B side A second valve body 62 that opens and closes. The first valve body 61 includes a first cylinder device 6 for driving the first valve body 61 to open and close.
7 is connected, the first cylinder device 67 has a piston 68 connected to the first valve body 61, and a cylinder that slidably accommodates the piston 68 and forms a pressure chamber C that presses the piston 68. 69. Similarly, a second cylinder device 70 for driving the second valve body 62 to open and close is connected to the second valve body 62, and the second cylinder device 70 includes a piston 71 connected to the second valve body 62, There is provided a cylinder 72 which accommodates the piston 71 slidably and forms a pressurizing chamber D which presses the piston 71. This second
When the valve body 62 is closed, the flow path to the secondary pipe is shut off via the valve opening 63, and the valve body 62 communicates with the exhaust pressure chamber F via the hollow passage of the second valve body 62. When the first valve body 61 is opened, water flows into the exhaust pressure chamber F.

The automatic valve 60 also connects the primary chamber A of the main body 65 to the pressurizing chamber C of the first cylinder device 67, and pressurizes the piston 68 in the cylinder 69 to move the piston 68 to the open position. Pressurized flow path 73 and first cylinder device 6
7, a first exhaust pressure passage 78 for stopping the pressurization of the piston 68 and moving the piston 68 in the cylinder 69 to the closed position by discharging the pressure of the pressurizing chamber C, and is connected to the first exhaust pressure passage 78. And a flow rate restricting device 75 for adjusting the flow rate according to the pressure of the secondary chamber B of the main body 65 and discharging while restricting the piston back pressure.

Similarly, in the second cylinder device 70, the primary chamber A of the main body 65 is communicated with the pressurizing chamber D of the second cylinder device 70, and the piston 71 in the cylinder 72 is pressurized to open the piston 71. Pressurized flow path 7 moved to
6 and a second exhaust pressure passage 77 that exhausts the pressure in the pressurizing chamber D of the second cylinder device 70 to stop pressurizing the piston 71 and moves the piston 71 in the cylinder 72 to the closed position. ing.

The automatic selection valve 66 of the automatic valve 60 has a structure as shown in FIG.
8 (discharge pressure passage), connected to the secondary chamber B of the main body 65 by a first input pipe 79, and connected to the pressurization chamber D of the second cylinder device 70 by a second input pipe 80. I have. Its function is that when the first valve body 61 is in the open position and the second valve body 62 is in the open position, the flow restricting device 75
Is communicated with the secondary chamber B of the main body 65, and when the first valve body 61 is in the open position and the second valve body 62 is in the closed position, the flow restricting device 75 is connected to the pressurizing chamber D of the second cylinder device 70. This is to communicate with the exhaust pressure chamber F on the back.

The automatic selection valve 66 selects the higher one of the secondary chamber B of the main body 65 and the exhaust pressure chamber F of the second cylinder device 70, and selects the selected one via the output pipe 78. Automatically connected to the flow restricting device 75.

Embodiment 4 FIG. FIG. 11 shows an automatic selection valve 66.
Is schematically shown. In this figure, the automatic selection valve 66 has, for example, a hollow cylindrical main body 81, and a valve seat 82 provided at a predetermined distance at both axial ends of the main body 81 and facing inward in the axial direction. The first and second valve openings 83 and 84 are slidably provided in the main body 81 so that the space in the main body 81 is divided into the first primary chamber 85 and the second primary chamber 85.
And a primary chamber 86 and a piston 87 partitioned into a primary chamber 86.
The main body 8 is connected to the first primary chamber 85 and the second primary chamber 86 defined by the piston 87 so as to communicate with each other.
1, a first input opening 88 and a second input opening 8
9 are formed.

The automatic selection valve 66 is further connected to both axial sides of the piston 87, and is connected to the first and second valve openings 8 described above.
3 and 84 are provided at a predetermined distance smaller than the distance between the valve openings 83 and 84, and the first and second valve openings 83 and 84 are disposed axially inward, i.e., on the primary chamber side 8.
First and second valve bodies 9 selectively opened and closed from 5, 86
1 and 92 are provided. First and second valve bodies 91
And 92 have a pressure receiving area smaller than the pressure receiving area of piston 87. Also, the first and second valve openings 8
Downstream of 3 and 84 are first and second secondary chambers 93 and 94, respectively, which are joined and communicate with a single output opening 95. At this time, in order to increase the pressure receiving area of the piston 87, the diameter of the piston 87 is increased, and
May be increased only in the diameter of the central portion.

In such an automatic selection valve 66, the first
From the input opening 88 and the second input opening 89 to the first primary chamber 8
When a pressure having a different size is introduced into the fifth and second primary chambers 89, for example, in FIG. 11, when the larger pressure is supplied to the first input opening 88 on the left side in the figure, the piston 87 is moved to its The larger pressure is pressed to the right in FIG. 11 to bring the first valve body 91 to the open position and to move the opposite valve, ie, the second valve body 92, to the closed position.

Embodiment 5 Automatic selection valve 9 shown in FIG.
In FIG. 5, the automatic selection valve 66 of FIG. 11 has almost the same shape and performs a different function. In order to selectively take out the pressure on the low pressure side as an output, the first and second valve openings 96,
97 has a valve seat 82 on the side of the secondary chambers 93 and 94, and first and second valve bodies 99 and 100 connected to a piston 98 are provided in the secondary chambers 93 and 94. Other configurations are the same as those of the embodiment shown in FIG. For example, when a larger pressure is supplied to the first input opening 88 on the left side in the figure, the piston 98 is pressed to the right in FIG. 12 by the larger pressure, and the first valve body 99 is set to the closed position and The opposite valve, ie, the second valve body 100, is moved to the open position.

Embodiment 6 FIG. Automatic selection valve 1 shown in FIG.
02 has the same overall configuration as the automatic selection valve 66 of FIG. 11, and includes first and second springs 103 and 104 provided between the piston 87 and the first and second valve bodies 91 and 92. The only difference is that Spring 10
Numerals 3 and 104 depress the valve bodies 91 and 92 elastically against the valve openings 93 and 94 when the piston 87 is at the neutral position to close both. The springs 103 and 104 have a predetermined stroke, and even if the piston 87 slightly moves from the neutral position, the first and second valve bodies 91 and 92 are both maintained in the closed positions, and the piston 87 is moved to the predetermined position. When the piston moves beyond the distance, the valve body on the opposite side to the moving direction of the piston 87 moves to the open position.

In such an automatic selection valve 102, when no pressure is applied to the first primary chamber 85 and the second primary chamber 86 or there is no large difference in the applied pressure, the piston 87
When a large pressure difference is not applied to the
And 92 are pressed against the valve seat by springs 103,104. For example, when the pressure in the first primary chamber 85 increases and the pressure difference exceeds a predetermined value, the piston 87 is moved to the right in FIG. 13 while compressing the second spring 104 according to the pressure difference. When the movement distance of the piston 87 exceeds the stroke of the first spring 102, the first valve body 91 is separated from the valve seat of the first valve opening 93 while the second valve body 92 is maintained in the closed position. open. When the pressure of the second primary chamber 86 becomes higher than that of the first primary chamber 85, the piston 87 is similarly moved to the position shown in FIG.
, The first valve body 91 is closed, and the second valve body 92 is closed.
Opens.

FIG. 14 is a flow chart showing the operation and equipment state of the watering system of the present invention shown in FIGS. That is, in normal times, the main valve of the automatic valve 60 of the watering system, that is, the first valve body 61 is fully closed, the main valve limit switch 110 is on, the maintenance valve, that is, the second valve body 62 is fully open, and the maintenance valve limit switch 111 is off. The remote start valve 112 is closed, the remote test valve 113 is closed, the secondary side B of the main valve 15 has no pressure, the pressure switch 114 is off, and the automatic drain valve 115 is open.

In this state, when a fire occurs, a remote start valve (pilot valve) 112 is started by remote start.
Is opened, the pressurizing chamber C is pressurized, the main valve 61 is opened, the main valve limit switch 110 is turned off, and the main valve is opened. As a result, flowing water is started and the secondary side B of the main valve 61 is started.
Is pressurized, the pressure switch 114 is turned on, and a running water signal is issued. At this time, the automatic drain valve 115 is closed. In the figure of the automatic selection valve 102, the valve on the left side is opened to start flowing water. However, since the pressure is regulated on the secondary side, water discharge at a predetermined pressure is realized.

When the watering system is to be restored for extinguishing a fire, the remote start valve (pilot valve) 112 is closed by a remote stop signal. Then, the pressure in the pressurizing chamber C is reduced, and the main valve 61 is gradually moved to the closed position by the quick closing prevention function of the pressure adjusting circuit 75, the secondary side B of the main valve 61 is reduced in pressure, and the pressure switch 114 is turned off. The running water signal stops. At this time, the automatic drain valve 115 is opened, both valves of the automatic selection valve 102 are closed, and residual water is discharged from the main valve 61.
The water discharge from the water discharge head 7 also stops, and when the main valve 61 is completely closed, the main valve limit switch 110 is turned on,
The running water stop operation is completed.

FIG. 15 is a flowchart showing the operation and the equipment state of the watering system according to the present invention at normal times, at the time of a functional test and at the time of restoration. Figure 14 shows the normal device status.
Is the same as the device state shown in the flowchart of FIG.

At the time of the test, the remote test valve 113 is opened by starting the remote test, the pressurizing chamber D of the maintenance valve 62 is pressurized, and the maintenance valve 62 is closed. It is confirmed that the maintenance valve limit switch 111 has been turned on, and it is determined that the water discharge test preparation has been completed.

Next, the remote start valve 11 is used to start the remote test.
2, the pressurizing chamber D is pressurized, the main valve 61 is opened, the main valve limit switch 110 is turned off, the main valve is opened, the flowing water is started, and the secondary side B of the main valve 61 is opened. Is pressurized, the pressure switch 114 is turned on, and a running water signal is issued. At this time, the automatic drain valve 115 is closed, and the automatic selection valve 102 is open at the right side in the figure. The discharge of water at a predetermined pressure to the exhaust pressure chamber F regulated by the start of the flow of water into the exhaust pressure chamber F is realized.

In this way, the function test of the automatic valve of the present invention can be confirmed by the procedure shown in the flowchart of FIG.

FIG. 16 is a flowchart at the time of restoration of the watering system of the present invention. When restoring the watering system after the end of the functional test, the remote start valve 112 is closed by the remote stop signal. Then, the pressure in the pressurizing chamber C is reduced, and the valve 61 is gradually reduced by the rapid closing prevention function of the pressure adjusting circuit 75.
Is moved to the closed position, the pressure on the secondary side B of the main valve 61 is reduced, the pressure switch 114 is turned off, and the flowing water signal is stopped.
At this time, the automatic drain valve 115 is open and the automatic selection valve 10
The two valves are both closed. The residual water is discharged from the main valve 61, the water discharge is stopped, and when the main valve 61 is completely closed, the main valve limit switch 110 is turned on, and the operation of stopping the flowing water is completed and the main valve 61 is restored. If the main valve limit switch 110 is not turned on, it is necessary to check the main valve 61 and the like to restore the main valve 61.

[0058]

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 pressure in the pressurizing chamber of the cylinder device to stop pressurizing the piston and move the piston in the cylinder to the closed position. An exhaust pressure passage to be moved, and a flow restricting device connected to the exhaust pressure flow passage for discharging while restricting the piston back pressure, wherein the flow restricting device is provided in a secondary pipe connected to the secondary chamber of the main body. The flow rate is adjusted according to the pressure of That is an automatic valve. Therefore, it is possible to provide an automatic valve capable of accurately monitoring the secondary pressure of the present valve and accurately adjusting the pressure of the extinguishing water to be supplied.

Further, the flow restricting device can be selectively switched between a first monitoring pipe communicating with a secondary pipe connected to the main body and a second monitoring pipe communicating with a secondary chamber of the main body. Even when testing at a factory without connecting an automatic valve to the secondary pipe, the test is performed with the automatic valve connected to the secondary pipe and installed in the watering system. It can be adapted freely in any case.

Further, since the opening of the exhaust pressure passage communicating with the pressurizing chamber is provided at a position which is at least partially covered by the piston when the piston is near the closed position, the water hammer has a simple structure. The occurrence of the phenomenon can be more reliably prevented.

Further, the automatic valve according to the present invention comprises 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, a piston connected to the valve element, and a piston. Equipped with a cylinder that slidably accommodates a piston, a cylinder device that opens and closes the valve, and a primary chamber of the main body that communicates with the pressurizing chamber of the cylinder device, pressurizes the piston in the cylinder to open the piston. A pressurizing flow path for moving, a discharging pressure flow path for discharging the 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, and a piston connected to the discharging pressure flow path A flow restricting device for discharging while limiting the back pressure of the piston, wherein the opening of the exhaust pressure passage communicating with the pressurizing chamber is at a position at least partially covered by the piston when the piston is near the closed position. It is what was kicked. Therefore, with a simple configuration, the speed of movement of the main valve to the closed position can be made slow just before the closed position, and the water hammer phenomenon can be reliably prevented without greatly affecting the closing time of the automatic valve.

Further, at a position where the outer peripheral wall of the piston covers at least the opening of the exhaust pressure flow path, the piston is separated from the cylinder wall with a predetermined gap to provide a predetermined flow resistance. Therefore, the water hammer phenomenon can be prevented by reducing the moving speed of the piston with a simple and highly reliable configuration.

Further, since the piston is provided with a small-diameter portion in the circumferential direction at the crown portion of the piston, it is possible to prevent the water hammer phenomenon by reducing the movement speed of the piston with high reliability with a simple structure. .

Further, the automatic selection valve according to the present invention comprises a main body having a primary chamber and a secondary chamber defined by a partition having a valve opening, a first valve element for opening and closing the valve opening from the primary chamber side, A first cylinder device that opens and closes the valve body, and includes a piston connected to the valve body and a cylinder that slidably houses the piston and forms a pressurizing chamber that presses the piston; A first pressurizing flow path that communicates with the pressurizing chamber of the first cylinder device to pressurize the piston in the cylinder and move the piston to the open position; A first exhaust pressure passage for stopping the pressurization and moving the piston in the cylinder to the closed position; and a first exhaust pressure passage connected to the first exhaust pressure passage for adjusting a flow rate according to the pressure of the secondary chamber of the main body, and Flow control to discharge while limiting pressure A second valve body that opens and closes the valve opening from the secondary chamber side, a second piston connected to the second valve body, and a second piston that slidably accommodates the second piston and presses the second piston. A second cylinder device for forming a second pressure chamber, a second cylinder device for opening and closing the second valve body, and a primary chamber of the main body communicating with the second pressure chamber of the second cylinder device; A second pressurizing flow path for pressurizing the second piston to move the second piston to the open position, and discharging the pressure of the second pressurizing chamber of the second cylinder device to stop pressurizing the second piston. A second exhaust pressure passage for moving the second piston in the second cylinder to the closed position, a flow restricting device, a secondary chamber of the main body, and an exhaust pressure chamber of the second cylinder device;
When the valve element is in the open position and the second valve element is in the open position, the flow restricting device communicates with the secondary chamber of the main body, and the first valve element is in the open position and the second valve element is in the closed position. Sometimes a flow control device is provided with a selection valve for communicating the flow restricting device with the exhaust pressure chamber of the second cylinder device.

Therefore, in the function test of the automatic valve, the fire extinguishing water can be supplied without being supplied to the secondary side or the secondary pipe connected to the automatic valve, and the secondary side pipe is not used in the factory. When installed in a watering system of a building or equipment, fire water is not discharged from the water discharge head, the surrounding area is not flooded, and there is no difficulty in treating fire water. In addition, it is possible to switch between testing the automatic valve only without connecting the secondary pipe to the automatic valve, and performing the function test with the secondary pipe connected and installing it in the watering system if necessary. Can be selectively executed.

Further, the selection valve may be configured to automatically connect the flow restricting device selectively to the higher one of the secondary chamber of the main body and the exhaust pressure chamber of the second cylinder device. Therefore, it is possible to perform the test of the automatic valve alone, and also to perform the function test in a state where the secondary pipe is connected and installed in the watering system if necessary, instead of manually.

Further, according to the automatic selection valve of the present invention, a hollow column-shaped main body, and first and second valve openings provided at predetermined axially opposite ends of the main body and having respective valve seats are provided. A piston slidably provided in the main body to partition a space in the main body into a first chamber and a second chamber, and the main body so as to communicate with the first chamber and the second chamber defined by the piston. And a first input opening and a second input opening provided at both sides of the piston, and are provided between the first and second valve openings, and have a distance smaller than a predetermined distance of the valve opening. , A first and a second valve element for selectively opening and closing the first and the second valve openings from the inside in the axial direction, and an output opening communicating with both the first and the second valve openings. It has. Therefore, if this automatic selection valve is used, it is possible to automatically perform the selection switching of the pipeline to be performed according to the magnitude of the two pressures so as to output the larger one of the pressures. In this case, it became possible to perform a function test of an automatic valve without actually discharging fire extinguishing water from a water discharge head.

Further, the first and second valve openings have valve seats on the secondary chamber side, and the first and second valve bodies connected to the piston are provided in the secondary chamber. Therefore, it is possible to automatically perform the selection switching of the pipeline to be performed according to the magnitude of the two pressures so as to output the smaller one of the pressures. The function test of the automatic valve can be performed without actually discharging water.

Further, first and second springs having a predetermined stroke are provided between the piston and the first and second valve bodies. Therefore, when the pressure difference does not exceed a predetermined value, both of the two valve elements may be closed so that both inputs are not output.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a state of monitoring an automatic valve according to the present invention.

FIG. 2 is a schematic sectional view showing a state of the automatic valve according to the present invention at the time of fire.

FIG. 3 is a schematic cross-sectional view showing a state at the time of inspection of the automatic valve of the present invention.

FIG. 4 is a schematic sectional view showing an example of a cylinder device for an automatic valve according to the present invention.

FIG. 5 is a schematic view showing a cylinder device of another embodiment of the automatic valve according to the present invention in a closed position.

FIG. 6 is a schematic view showing a cylinder device of another embodiment of the automatic valve of the present invention in an open position.

FIG. 7 is a schematic sectional view showing a normal state of still another embodiment of the automatic valve of the present invention.

FIG. 8 is a schematic cross-sectional view showing a state at the time of a fire of still another embodiment of the automatic valve of the present invention.

FIG. 9 is a schematic cross-sectional view showing a state of a still further embodiment of the automatic valve according to the present invention during a function test standby.

FIG. 10 is a schematic sectional view showing a state of a further embodiment of the automatic valve according to the present invention during a function test.

FIG. 11 is a schematic view showing an embodiment of an automatic selection valve that can be used for the automatic valve of the present invention.

FIG. 12 is a schematic view showing another embodiment of the automatic selection valve of the present invention.

FIG. 13 is a schematic view showing still another embodiment of the automatic selection valve of the present invention.

FIG. 14 is a flowchart showing the operation of the automatic valve shown in FIG. 7 in the event of a fire.

FIG. 15 is a flowchart showing an operation of the automatic valve shown in FIG. 7 during a function test.

FIG. 16 is a flowchart showing the operation of the present invention when the automatic valve shown in FIG. 7 is restored.

FIG. 17 is a schematic diagram showing an example of a watering system using an automatic valve.

FIG. 18 is a schematic cross-sectional view showing a state when monitoring a conventional automatic valve.

[Explanation of symbols]

12 valve seat, 13 partition, A primary chamber, B secondary chamber, 1
4 body, 15 valve body, 17 piston, 18 cylinder, 25 pressurized flow path, 30 flow restriction device, 33 cylinder device, 34 pressurized chamber, 35 exhaust pressure flow path, 81 main body, 82 valve seat, 83, 84 valve opening, 85 Room 1
86 second chamber, 87 piston, 88, 89 input opening, 95a output opening, 91, 92 valve body, 95 automatic selection valve, 96, 97 valve opening, 93, 94 secondary chamber, 9
8 piston, 99, 100 valve body, 102 automatic selection valve, 103, 104 spring.

Claims (11)

[Claims] 1. A main body having a primary chamber and a secondary chamber partitioned by a partition having a valve opening, a first valve body for opening and closing the valve opening from the primary chamber side, and a piston connected to the valve body And a cylinder device for slidably housing the piston and forming a pressurizing chamber for pressing the piston, and a cylinder device for driving the valve element to open and close; and a primary chamber of the main body as a pressurizing chamber of the cylinder device. A pressurizing flow path that communicates and pressurizes a piston in the cylinder to move the piston to an open position; and discharges a pressure in a pressurizing chamber of the cylinder device to stop pressurizing the piston and to release the pressure in the cylinder. An exhaust pressure passage for moving the piston to a closed position, and a flow restricting device connected to the exhaust pressure flow passage for discharging while limiting the piston back pressure, wherein the flow restricting device is a secondary of the main body. Automatic valve whose flow rate is adjusted according to the pressure in the secondary pipe connected to the chamber. 2. The flow control device according to claim 1, wherein the flow rate restriction device is provided between a first monitoring pipe communicating with the secondary pipe connected to the main body and a second monitoring pipe communicating with the secondary chamber of the main body. The automatic valve according to claim 1, further comprising a monitoring pressure switching valve that can be selectively switched. 3. An opening of the exhaust pressure passage communicating with the pressurizing chamber is provided at a position at least partially covered by the piston when the piston is near a closed position. Automatic valve. 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 to be moved; a discharge pressure flow path to discharge the pressure of the pressurizing chamber of the cylinder device to stop pressurizing the piston and move the piston in the cylinder to a closed position; A flow restricting device for discharging while restricting the back pressure of the piston, wherein the opening of the discharge pressure passage communicating with the pressurizing chamber is provided when the piston is near a closed position. An automatic valve provided at a position at least partially covered by 5. In a position where an outer peripheral wall of the piston covers at least an opening of the exhaust pressure flow path, the piston is separated from a cylinder wall of the cylinder with a predetermined gap to provide a predetermined flow path resistance. The automatic valve according to claim 4, wherein 6. The automatic valve according to claim 4, wherein the piston has a small circumferential portion at a crown portion of the piston. 7. A main body having a primary chamber and a secondary chamber partitioned by a partition having a valve opening, a first valve body that opens and closes the valve opening from the primary chamber side, and connected to the first valve body. A first cylinder device that opens and closes the valve body, the first cylinder device including a piston that slidably accommodates the piston and pressurizes the piston by slidably housing the piston; A first pressurizing flow path that communicates with a pressurizing chamber of the cylinder device, pressurizes a piston in the cylinder to move the piston to an open position, and discharges a pressure of the pressurizing chamber of the first cylinder device to A first exhaust pressure passage for stopping the pressurization of the piston and moving the piston in the cylinder to a closed position, and a flow rate adjustment connected to the first exhaust pressure passage and corresponding to the pressure of the secondary chamber of the main body. To control the piston back pressure. A flow restriction device for discharging with the valve and a second valve body opening to open and close the secondary chamber side, the second piston connected to said second valve member and the second
A second cylinder device for slidably housing the piston and forming a second pressurizing chamber for pressing the second piston, and a second cylinder device for driving the second valve body to open and close; A second pressurizing flow path that communicates with a second pressurizing chamber of the second cylinder device and pressurizes a second piston in the second cylinder to move the second piston to an open position; A second exhaust pressure passage for discharging the pressure of the second pressurizing chamber to stop pressurizing the second piston and moving the piston in the second cylinder to a closed position; When the first valve element is in the open position and the second valve element is in the open position, the flow restricting device is connected to the secondary chamber of the main body. And the second valve is in the open position and the second valve is in the open position. Automatic valve body that includes a selection valve when in the closed position for communicating said flow restriction device to a discharge chamber of the second cylinder device. 8. The flow control device according to claim 7, wherein the selection valve selectively and automatically connects the flow restricting device to a higher one of a secondary chamber of the main body and a discharge chamber of the second cylinder device. Automatic valve as described. 9. A hollow column-shaped main body, first and second valve openings provided at predetermined distances at both ends in the axial direction of the main body and each having a valve seat, and slidably provided in the main body. A piston for dividing a space inside the main body into a first chamber and a second chamber; a first input opening provided in the main body so as to communicate with the first and second chambers defined by the piston; A second input opening, connected to both axial sides of the piston, provided between the first and second valve openings, and provided at a distance smaller than a predetermined distance of the valve opening; An automatic selection valve having first and second valve bodies for selectively opening and closing the second valve opening from the inside in the axial direction, and an output opening communicating with both the first and second valve openings. 10. A hollow column-shaped main body, first and second valve openings provided at predetermined distances at both ends in the axial direction of the main body and each having a valve seat, and slidably provided in the main body. A piston for dividing a space inside the main body into a first chamber and a second chamber; a first input opening provided in the main body so as to communicate with the first and second chambers defined by the piston; A second input opening, connected to both axial sides of the piston, provided between the first and second valve openings, and provided at a distance smaller than a predetermined distance of the valve opening; First and second valve bodies for selectively opening and closing the second valve opening, and an output opening communicating with both the first and second valve openings, wherein the first and second valve openings are Hold the valve seat on the secondary chamber side,
An automatic selection valve, wherein the first and second valve bodies connected to the piston are provided in the secondary chamber. 11. The automatic selection valve according to claim 9, wherein first and second springs having a predetermined stroke are provided between the piston and the first and second valve bodies.