JP5767181B2 - On-off valve unit - Google Patents

Description

  The present invention relates to an on-off valve unit of a water discharge / sprinkling facility for fire and disaster prevention that can reduce impact pressure due to water hammer.

  Sprinkler fire-fighting equipment, water gun equipment, water sprinkler equipment, etc., for fire and disaster prevention water discharge / sprinking equipment, an open / close valve is provided in the middle of the piping for the equipment, and an opening such as a water spray gun or water spigot is provided at the end of the pipe. It is done. Among these firefighting disaster prevention water spraying and sprinkling facilities, dry-type firefighting disaster prevention equipment in which the primary side (upstream side) of the on-off valve in the piping is filled and pressurized, and the secondary side (downstream side) is a gap In the piping, the pressurized water on the primary side flows into the secondary side vigorously after the opening / closing valve is opened, and at the moment when the water is filled up to the opening on the secondary side, the flow velocity is drastically reduced and water hammer occurs. It is known that the magnitude of the impact pressure due to this water hammer depends on the difference in water flow velocity before and after the secondary side pipe is filled and the propagation speed of the pressure wave in the water. In order to reduce the impact pressure due to such a water hammer, an on-off valve is known in which the opening of the valve is reduced to suppress the flow rate (initial flow rate) until the secondary side pipe is filled with water ( Patent Documents 1 and 2).

  However, in order to control the initial flow rate to the secondary side, this on-off valve is temporarily stopped at the half-open position and fully opened at the timing when the secondary side pressure increase is detected. Therefore, if the dry piping from the on-off valve to the opening is long, or if the opening of the half-opening is set small, it will take a long time from standby to water discharge, and the fire will spread or spread during that time There's a problem. In addition, if a malfunction occurs in the mechanism that detects the pressure increase on the secondary side, the half-open state is maintained, and there is a concern on safety consequences that a sufficient water discharge amount cannot be obtained.

JP 2002-13663 A JP-A-5-253314

  DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-described conventional situation, and can reduce the impact pressure due to water hammer when performing water discharge, and has a short time until the start of water discharge from a standby state. An on-off valve unit is provided.

  The on-off valve unit of the present invention is an on-off valve unit that is provided on a pipe of a fire-fighting disaster prevention water discharge / sprinkling facility that has an on-off valve, the secondary side pipe of the on-off valve is dry and has an opening for water discharge. A throttle portion provided on a primary side and / or a secondary side of the on-off valve and having a reduced cross-sectional area of the pipe flow path; an intake port provided on a secondary side of the throttle portion; An aeration mechanism having a check valve that prevents backflow from the mouth is provided.

In the on-off valve unit of the present invention, the primary side and / or the secondary side of the on-off valve are provided on the secondary side of the throttle part with a narrowed cross-sectional area of the water discharge / sprinkling equipment piping for fire fighting and disaster prevention. An aeration mechanism having an intake port and a check valve that prevents backflow from the intake port is provided. For this reason, when the on-off valve is driven and fire water flows into the secondary side pipe, the secondary side of the throttle portion of the air mixing mechanism provided on the primary side and / or the secondary side of the on-off valve is large. The pressure is lower than the atmospheric pressure, air flows into the pipe from the intake port, and bubbles are mixed into the water for fire fighting. Thus, the fire-fighting water containing bubbles travels toward the opening provided on the secondary side, reaches the opening, and is discharged from the opening. Here, the flow speed of the fire-fighting water upstream of the opening is suddenly decelerated after reaching the opening, so that an impact pressure due to water hammer is generated. However, many bubbles existing in the pipe contract due to the impact pressure, so that the impact pressure is absorbed. For this reason, propagation of the impact pressure due to water hammer when performing water discharge is suppressed, and the impact pressure can be reliably reduced.
In addition, since a mechanism for stopping the opening of the on-off valve at the half-open position is not provided and the valve is fully opened from the beginning, the time until the water is discharged from the standby state is short, and a prescribed water discharge amount can be obtained from the initial stage of water discharge.
Furthermore, due to the presence of the check valve, water can be supplied and discharged as usual without air bubbles being mixed after the secondary side pipe is filled.

  It is preferable that the cross-sectional area of the narrowest part of the narrowed portion is 30% or more and less than 80% of the cross-sectional area of the pipe flow path of the portion that is not restricted. If the cross-sectional area of the narrowest part of the throttle part is 30% or more of the cross-sectional area of the pipe channel of the non-squeezed part, the pressure loss is small and the water supply capacity is reduced due to the provision of the throttle part. Since it is small, sufficient water can be discharged from the opening. Further, if the cross-sectional area of the narrowest portion of the throttle portion is less than 80%, the effect of reducing the pressure on the secondary side of the throttle portion can be sufficient, and air from the intake port can be sufficiently taken in. . For this reason, the amount of bubbles generated in the water for fire fighting increases, and as a result, the effect of reducing the impact pressure of water hammer is sufficient.

  Here, when the air mixing mechanism is provided on the secondary side of the on-off valve, it is preferable that the throttle portion is a jet that gradually narrows the inner diameter of the pipe. The jet has a high ability to take in air and has an excellent effect of reducing the impact pressure of water hammer. Further, even if the intake port is arranged near the jet, a large amount of air can be taken in, so that the on-off valve unit can be downsized.

  Furthermore, it is preferable to provide a cylindrical diffuser having an inlet having an inner diameter that is larger than the opening diameter of the jet outlet and less than the inner diameter of the pipe, in the vicinity of the jet outlet. As a result, even if the piping on the secondary side of the on-off valve unit is a long distance or rises in the vertical direction, for example, when water head pressure is generated, air can be taken in stably and sufficient water can be taken in. The effect of reducing the impact pressure of the impact can be achieved. More preferable is a tapered shape in which the diffuser has a larger diameter toward the downstream side.

  In addition, when the air mixing mechanism is provided on the secondary side of the on-off valve and the throttle part is an orifice that suddenly reduces the inner diameter of the pipe, the distance from the on-off valve to the orifice is 1 of the inner diameter of the pipe. It is preferably 5 times or more. Since the region where the distance from the on-off valve is 1.5 times the pipe inner diameter or more is a laminar flow region, air intake from the intake port is stable, and the impact reduction effect of water hammer is also stable. Because.

  Furthermore, the on-off valve can be an automatic valve. If it is like this, other power sources, such as electric power and compressed air, are not required for control of an on-off valve main body, but an on-off valve main body can be opened and closed only with the water pressure of the on-off valve primary side.

  Here, the automatic valve is preferably a simultaneous opening valve. In this way, the time from the start of water discharge until the water discharge speed becomes maximum can be extremely shortened. In addition, the pressure loss of the valve body can be reduced.

  The automatic valve preferably includes a pilot mechanism that detects the pressure on the secondary side and adjusts the opening degree. If it is like this, it will become possible to control the pressure of a secondary side uniformly also with respect to the change of the number of openings and the amount of discharged water.

  Moreover, it is preferable that the automatic valve has an activation valve, and the time from when the activation valve is opened until the valve opening is fully opened is within 15 seconds. In this way, it is possible to extinguish the protection target at an early stage or to prevent the fire from spreading to the protection target.

It is sectional drawing which showed the standby state of the on-off valve unit of Example 1. FIG. It is sectional drawing which showed the state immediately after starting of the on-off valve unit of Example 1. FIG. It is sectional drawing which showed the water discharge state of the on-off valve unit of Example 1. FIG. It is a schematic diagram of the simulation fire-fighting disaster prevention equipment for evaluating the characteristic of an on-off valve unit. It is a graph which shows the time-dependent change of the water hammer pressure of the on-off valve unit (with an air mixing mechanism) of an Example. It is a graph which shows the time-dependent change of the water hammer pressure of the on-off valve unit (without an air mixing mechanism) of a comparative example. It is a graph which shows the relationship between the opening degree of an orifice, and a water hammer pressure, and the relationship between the opening degree of an orifice, and a pressure loss. (A) is sectional drawing which showed the standby state of the on-off valve unit of Example 2. FIG. (B) is a modification of the second embodiment provided with a diffuser. It is a graph which shows the relationship between the secondary side pressure loss and air suction flow volume in Example 2 and its modification. It is sectional drawing which showed the standby state of the on-off valve unit of Example 3. It is sectional drawing of the pilot valve 40 part of the on-off valve unit of Example 3.

  The on-off valve unit of the present invention can be installed as long as it is a piping for a fire-fighting disaster prevention water discharge / sprinkling facility having an on-off valve, the secondary side of the on-off valve being dry and having an opening for water discharge. Such fire-fighting disaster prevention water spraying / sprinkling equipment includes, for example, a fire extinguishing system in which an on-off valve is opened in the event of a fire and supplying fire-fighting water to a water spray gun or sprinkler faucet provided at the end of a pipe, or radiant heat of fire Watering equipment for protecting the equipment from the above.

  The on-off valve used in the on-off valve unit of the present invention is not particularly limited, but is preferably an automatic valve that can control the pressure on the secondary side. If it is an automatic valve, the pressure and flow rate can be adjusted automatically.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.
Example 1
<Configuration>
In FIG. 1, the on-off valve unit 1 of Example 1 is shown. This on-off valve unit 1 is inserted in the middle of a pipe 2 of a water discharge / sprinkling facility for fire fighting disaster prevention. A water discharge opening 3 is provided at the tip of the pipe 2, and the other end is connected to a water pump (not shown). The on-off valve unit 1 includes an automatic valve 4 and an air mixing mechanism 5 provided on the secondary side of the automatic valve 4.

  The automatic valve 4 is a simultaneous opening valve, and is provided with a communication hole 8 for communicating the primary side flow path 6 and the secondary side flow path 7. A valve seat 9 is formed at the upper edge of the communication hole 8, and a valve body 10 is pressure-bonded to the valve seat 9 by receiving pressure on the primary side. The valve body 10 is coaxial and is attached to the tip of the spindle 11. It is fixed. The spindle 11 penetrates upward in the valve communicating with the primary side flow path 6 and enters the piston chamber 12, further penetrates the upper end of the piston chamber 12 and protrudes upward, and a handle 13 is attached to the tip. Yes. A piston 14 is coaxially fixed at the center of the spindle 11 and divides the piston chamber 12 vertically. The piston 14 can move up and down in the piston chamber 12 together with the spindle 11. The spindle 11 is moved up and down in conjunction with the vertical movement of the piston 14 and the rotation of the handle 13. One end side of the start pipe 16 is connected to the primary side flow path 6, and the other end side communicates with the lower part in the piston chamber 12 through the start valve 17.

  Further, in the secondary pipe 2 of the automatic valve 4, an orifice 18 having a flow passage section narrowed to 50% toward the secondary side is provided, and an intake pipe is provided on the secondary side of the orifice 18. 19 is connected, and a check valve 20 is attached to the tip of the intake pipe 19. The orifice 18, the intake pipe 19, and the check valve 20 are the aeration mechanism 5. The distance between the automatic valve 4 and the narrowest portion of the orifice 18 is twice the inner diameter of the pipe 2.

  In the automatic valve 4, the time from when the start valve 17 is opened until the valve opening is fully opened is within 15 seconds.

<Effect>
(Standby)
In the on-off valve unit 1 of Example 1 configured as described above, in the standby state, the primary-side flow path 6 is filled with fire-fighting water in a pressurized state, and the secondary-side flow path 7 is empty. It is said that. The start valve 17 is closed, and the piston chamber 12 is empty. For this reason, the valve body 10 is pressure-bonded to the valve seat 9 by pressure received from the fire water in the primary flow path 6 and the communication hole 8 is closed, whereby the secondary flow of the fire water in the primary flow path 6 is closed. Movement to road 7 is blocked.

(At startup)
As shown in FIG. 2, when the start valve 17 is changed from the closed state to the open state, the fire water in the primary side flow path 6 flows into the piston chamber 12 through the start pipe 16. Since the pressure receiving area of the piston 14 is larger than the pressure receiving area of the valve body 10, the piston 14 is pushed up by the pressure of the fire water flowing into the piston chamber 12, and the spindle 11 rises together with the valve body 10. As a result, the fire-fighting water in the primary channel 6 flows into the secondary channel 7 through the communication hole 8 and passes through the orifice 18. Here, the pressure on the secondary side of the orifice 18 becomes lower than the atmospheric pressure, and air enters the pipe 2 from the intake pipe 19 through the check valve 20 and is mixed with fire-fighting water to form bubbles.

(During water discharge)
As shown in FIG. 3, the fire-fighting water containing bubbles further travels in the pipe 2 and finally reaches the opening 3 to be discharged. Since the opening 3 is narrower than the inner diameter of the pipe 2, the fire-fighting water containing bubbles that have reached the opening 3 suddenly slows down, and an impact pressure is generated by water hammer. This impact pressure (compression wave) propagates in the direction opposite to the traveling direction of the fire-fighting water containing bubbles. However, this impact pressure is absorbed by the contraction of the bubbles contained in the water for fire fighting, and the propagation of the impact pressure is reduced.

  Therefore, according to the on-off valve unit 1 of the first embodiment, it is possible to reliably reduce the water hammer pressure when water is discharged. Further, the valve element 10 is separated from the communication hole 8 at once, and the opening degree is fully opened from the beginning. Furthermore, since the time from the opening of the start valve 4 to the opening degree of the valve opening is as short as 15 seconds, it is in a standby state. It takes a short time to discharge water. Further, the presence of the check valve 20 can prevent the fire water from flowing backward from the intake pipe 19 after the secondary side flow path 7 is filled.

(Comparative Example 1)
The on-off valve unit of Comparative Example 1 is the same as the on-off valve unit of Example 1 except that the air mixing mechanism 5 is not provided, and the same components are denoted by the same reference numerals and detailed. The detailed explanation is omitted.

  In the on-off valve unit of Comparative Example 1, since the air mixing mechanism is not provided, the start valve 17 is opened to open the automatic valve 4 and the fire water in the primary side flow path 6 flows into the secondary side flow path 7. Even if letting it, air bubbles are not mixed in the fire water. For this reason, even if the speed of the fire-fighting water at the moment of reaching the opening 3 changes suddenly and a water hammer in the direction opposite to the traveling direction of the fire-fighting water occurs, the impact pressure due to this water hammer cannot be absorbed. For this reason, the impact pressure propagates to the entire pipe including the secondary side flow path 7 and the primary side flow path 6.

-Evaluation test-
In order to confirm the effect of the on-off valve unit of the present invention, a simulated watering facility shown in FIG. 4 was produced and an evaluation test was performed. In this simulated watering equipment, the on-off valve unit 1 of the first embodiment is connected to one end of a secondary side pipe 21, and a watering pipe 22 is connected in a T shape to the other end.
However, the distance from the automatic valve 4 to the orifice 18 is two types, 0 and 9.5d (d is the inner diameter of the simulated watering equipment pipe 2), and the opening of the orifice 18 (that is, the flow path of the narrowest part of the orifice 18). The cross-sectional area / flow-path cross-sectional area of the simulated watering equipment pipe 2)) was set to four types of 0.4, 0.6, 0.8, and 1.0, and a total of eight on-off valve units were produced. Note that an opening degree of 1.0 indicates that no orifice is attached.

  The sprinkling pipe 22 is provided with five openings on the left and right sides, a total of ten openings 23 projecting upward at equal intervals. The lengths of the secondary side pipe 21 and the sprinkling pipe 22 are both 11 m, and the primary side of the automatic valve 4 is connected to the primary side pipe 24. Pressure gauges P1 and P2 are installed on the primary side and the secondary side of the automatic valve 4, respectively, and a pressure gauge P3 is connected to one end of the sprinkling pipe 23. The pressure gauge P3 is connected to the data logger 25 so that the pressure can be recorded over time.

  For the on-off valve unit of Comparative Example 1, the same simulated watering equipment was produced and its evaluation test was performed.

The measurement conditions are as follows.
-Primary pressure before opening of automatic valve 4: 1.0 MPa
-Initial flow rate immediately after opening the automatic valve 4: 3900 L / min
-The amount of water discharged from one opening 23: 186 L / min (at 0.75 MPa)
・ Primary side piping 24: JIS10K 100A SGP pipe (no plating)
・ Secondary side piping 21: JIS10K 100A SGP pipe (no plating)
Length 11m
・ Watering pipe 22: JIS10K 80A SGP pipe (no plating)
Length 5.5m x 2

(Result)
Changes with time of the water hammer pressure recorded by the data logger 5 are shown in FIGS. Here, FIG. 5 shows a result of the opening / closing valve unit of the air mixing mechanism in which the distance from the automatic valve 4 to the orifice 18 having the opening degree of 0.6 is 9.5 d. FIG. 6 shows the result of the on-off valve unit having no air mixing mechanism.

  As shown in FIG. 6, in the on-off valve unit of the comparative example that does not have the air mixing mechanism, the pressure suddenly rises and a large water hammer pressure of 2.5 MPa is generated at the maximum. On the other hand, in the on-off valve unit of the embodiment having the air mixing mechanism, as shown in FIG. 5, the pressure rises more slowly than in the comparative example having no air mixing mechanism, and the maximum value of the water hammer pressure is also high. 1.6 MPa, a reduction of 36%.

  The “relation between the opening of the orifice 18 and the water hammer pressure” is shown in FIGS. A curve of “water hammer pressure characteristic in the case of only an orifice” in the figure is a water hammer pressure characteristic by opening of the pure orifice 18 measured without intake. The water hammer pressure is lower as the opening of the orifice 18 is smaller. This is because the flow rate is reduced by the orifice 18.

Next, the measurement results in a state where the distance from the automatic valve 4 to the orifice 18 is 0 and intake is possible are shown in the figure (a: rhombus plot). As can be seen from the results, it is almost the same value as the “water hammer pressure characteristic in the case of only the orifice”, which is reduced by suppressing the flow rate of the orifice 18, and it can be seen that the effect of the air mixing mechanism is not obtained. This is presumably because the flow becomes turbulent at a position close to the automatic valve 4 and the air mixing mechanism is not operating properly.

On the other hand, the measurement result in a state where the distance from the automatic valve 4 to the orifice 18 is 9.5 d and intake is possible is shown in the figure (b: square plot). In this case, the water hammer value is lower than when the distance from the automatic valve 4 to the orifice 18 is 0, and the water hammer pressure is lower as the opening of the orifice 18 is smaller. I understand that it is obtained. Therefore, from experience, it is preferable to install the orifice 18 at a position 1.5 times or more from the automatic valve 4 in a laminar flow state, more preferably 2 times or more, and most preferably 5 times or more.

  On the other hand, the relationship between the “opening of the orifice 18 and the pressure loss of the on-off valve unit” is shown in FIG. 7 (c: broken line (pressure loss value is 0.1 times the vertical axis display value)). Thus, the smaller the opening of the orifice 18, the larger the tendency.

  From the above results, it can be seen that there is a trade-off between reducing the opening of the orifice 18 and mixing bubbles to reduce the water hammer pressure and reducing the pressure loss of the on-off valve unit body. It was. For this reason, it is preferable that the opening degree is 30% or more and less than 80% in consideration of both. More preferred is 40% or more and less than 70%, and most preferred is 45% or more and less than 65%.

(Example 2)
The on-off valve unit of the second embodiment is obtained by replacing the orifice 18 in the on-off valve unit 1 of the first embodiment with a jet 30 as shown in FIG. The jet 30 is provided at a position immediately after the downstream side of the automatic valve 4. In this way, the intake air amount can be increased even with the same water flow rate as in the case of the orifice. The jet 30 has a cylindrical shape whose inner diameter gradually decreases from the primary side to the secondary side. Others are the same as the on-off valve unit of the first embodiment, and the same components are denoted by the same reference numerals and detailed description thereof is omitted.

  In the on-off valve unit of the second embodiment, since the inner diameter of the jet 30 is gradually reduced from the primary side toward the secondary side, the pressure on the secondary side decreases due to the flow of fire-fighting water like the orifice 18. Thereby, air is taken in from the intake pipe 19 and air bubbles are mixed into the water for fire fighting. For this reason, the foam absorbs water hammer pressure like Example 1, and can reduce the water hammer pressure at the time of discharging water reliably. Further, the jet 30 has a high ability to take in air, and has an excellent effect of reducing the impact pressure of water hammer. Further, although the intake port 20 is provided close to the jet 30, a sufficient amount of air could be taken in. For this reason, the on-off valve unit can be miniaturized.

  As a modification of the second embodiment, as shown in FIG. 8B, a cylindrical diffuser 31 having an inlet having an inner diameter larger than the opening diameter of the jet outlet and smaller than the inner diameter of the pipe in the vicinity of the outlet of the jet 30. May be provided. If this is the case, even when the length from the jet 30 to the opening 3 is long and the pressure loss between them is large, the ability to take in air is high, so that it was possible to sufficiently reduce the impact pressure of water hammer. (See FIG. 9). Furthermore, it is preferable that the diffuser has a tapered shape with a larger diameter toward the downstream.

(Example 3)
The third embodiment is an on-off valve unit having a pilot mechanism that detects the pressure of the secondary side pipe of the on-off valve unit and adjusts the opening, and as shown in FIG. 10, the control chamber 41 of the pilot valve 40 and the pipe 2 is connected by a pressure detection pipe 42, and the valve chamber 43 of the pilot valve 40 is connected to the starting pipe 16. The pilot valve 40 and the pressure detection pipe 42 are a pilot mechanism.

As shown in FIG. 11, a valve body 44 and a valve seat 45 are provided in the valve chamber 43, and the upper end of the valve body 44 is slidably inserted into the control chamber 41 side so as to be vertically slidable. The upper end of the valve body 44 is connected to a diaphragm 46 in the control chamber 41, and the upper side of the diaphragm 46 is connected to a coil spring 47. An adjustment handle 48 that protrudes from the upper end of the control chamber 41 and adjusts the urging force of the coil spring 47 is provided.
Others are the same as the on-off valve unit of the first embodiment, and the same components are denoted by the same reference numerals and detailed description thereof is omitted.

  In the on-off valve unit of the third embodiment configured as described above, when the start valve 17 is opened to open the on-off valve 4 and fire water is introduced into the pipe 2, the pressure in the pipe 2 is changed to the pressure detection pipe 42. Is transmitted to the lower part of the diaphragm 46 of the control chamber 41 of the pilot valve 40, and overcomes the urging force of the coil spring 47 to push up the diaphragm 46. As a result, the valve body 44 in the valve chamber 43 approaches the valve seat 45, the amount of water flow decreases, and the pressure in the piston chamber 12 of the on-off valve 4 decreases. When the pressure in the piston chamber 12 is lowered, the piston 14 is lowered and the opening degree of the on-off valve 4 is lowered. Thereby, the inflow amount of the water for fire fighting into the piping 2 decreases, and a pressure falls. In this way, when the pressure on the secondary side of the on-off valve is fed back to the lower portion of the diaphragm 46 of the control chamber 41 of the pilot valve 40 by the pressure detection pipe 42 and the pressure drops too much, conversely, by the biasing force of the coil spring 47 The valve body 44 moves away from the valve seat 45, increases the amount of water flow, and increases the opening degree of the automatic valve 4 again. By such a feedback function, the pressure on the secondary side of the on-off valve is stabilized, and as a result, fire water can be stably supplied.

  About the other, the effect similar to the on-off valve unit of Example 1 can be show | played.

In the first to third embodiments, the air mixing mechanism 5 is installed on the secondary side of the automatic valve 4, but it may be installed on the primary side or on both the primary side and the secondary side.
The present invention is not limited to the description of the embodiments of the invention. Various modifications are also included in the present invention as long as those skilled in the art can easily conceive without departing from the scope of the claims.

DESCRIPTION OF SYMBOLS 1 ... On-off valve unit 4 ... Automatic valve 3 ... Opening 2 ... Piping 18, 30 ... Restriction part (18 ... Orifice, 30 ... Jet)
19 ... Inlet (intake pipe)
20 ... Check valve 5 ... Air mixing mechanism 40, 42 ... Pilot mechanism (40 ... Pilot valve, 42 ... Pressure detection piping)
17 ... Start valve 31 ... Diffuser

Claims (6)

An on-off valve unit provided on the pipe of a fire-fighting water discharge / sprinkling facility for fire-fighting and disaster prevention, comprising an on-off valve, the secondary side pipe of the on-off valve being dry and having an opening for water discharge,
A throttle portion provided on the secondary side of the on-off valve and having a reduced cross-sectional area of the pipe flow path, an intake port provided on the secondary side of the throttle portion, and a check that prevents backflow from the intake port And an aeration mechanism having a valve ,
The throttle portion is a jet, and an on-off valve having a cylindrical diffuser having an inlet having an inner diameter that is larger than an opening diameter of the jet outlet and smaller than an inner diameter of the pipe is provided in the vicinity of the jet outlet. unit.   2. The on-off valve unit according to claim 1, wherein the flow path cross-sectional area of the narrowest portion of the throttle portion is 30% or more and less than 80% of the cross-sectional area of the pipe flow path of the non-throttle portion. The on-off valve unit according to claim 1 or 2 , wherein the on-off valve is an automatic valve. 4. The on-off valve unit according to claim 3 , wherein the automatic valve is a simultaneous open valve. The on-off valve unit according to claim 3 or 4 , wherein the automatic valve includes a pilot mechanism that detects the pressure on the secondary side and adjusts the opening degree. The automatic valve has a starting valve, according to any one of claims 3 to 5 times from the opening of the activation valve to the valve opening degree is fully opened is equal to or is within 15 seconds Open / close valve unit.

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