JP2022039214A - Foam fire extinguishing facility - Google Patents

Abstract

To provide a foam fire extinguishing facility equipped with mixing units capable of keeping a concentration of a diluted fire extinguishing agent constant with respect to a wide range of flow rates.SOLUTION: A foam fire extinguishing facility comprises: a plurality of foam discharge heads arranged in sections in an area; a pump for water supply; a first mixing unit and a second mixing unit that mix a foam fire extinguishing agent to inflow water to dilute the agent to a predetermined concentration, and supply the resultant out; a three-way switching valve with one inflow port and two discharge ports, capable of switching a water passage into which water flows; and a foam fire extinguishing agent storage tank storing the foam fire extinguishing agent and capable of supplying the foam fire extinguishing agent to the first mixing unit and the second mixing unit. In the foam fire extinguishing facility, the first mixing unit is configured to be able to flow out more diluted foam fire extinguishing agent as compared with the second mixing unit, one of the discharge ports of the three-way switching valve is set in such a manner that a cross-sectional area of the one discharge port is larger than that of the other discharge port, the first mixing unit is connected to the one discharge port, and the second mixing unit is connected to the other discharge port.SELECTED DRAWING: Figure 1

Description

The present invention relates to a foam fire extinguishing system using a foam fire extinguishing agent, and more particularly to a foam fire extinguishing system using a mixing device having a fire extinguishing agent flow regulator.

In the foam fire extinguishing equipment, a fire extinguishing agent mixing device that mixes water with the extinguishing agent to dilute it is provided, and it is necessary to keep the fire extinguishing agent concentration constant for a wide range of flow rates from a small flow rate to a large flow rate. Therefore, a flow rate detector is installed in the middle of the piping to send the fire extinguishing agent to acquire the flow rate information, the acquired flow rate information is passed to the controller, and the controller controls the solenoid valve in the middle of the piping according to the flow rate information and automatically opens. An invention has been proposed in which a valve is operated to switch a mixer that mixes a foam stock solution with running water for each of a small flow rate, a medium flow rate, and a large flow rate (Patent Document 1).

Japanese Unexamined Patent Publication No. 64-1-1570 Japanese Unexamined Patent Publication No. 2006-296918

However, the invention described in Patent Document 1 has a problem that an electrical control system is required, which complicates the system and leads to an increase in cost.

Therefore, a fire extinguisher flow regulator that adjusts the mixing concentration of the fire extinguisher stock solution of the fire extinguisher mixing device that supplies and mixes the fire extinguisher stock solution from the fire extinguisher storage tank to the running water sent to the discharge port for extinguishing the fire. A reduced diameter portion formed narrower than the flow path of the fire extinguishing agent stock solution located on the upstream side and a variable means for variably adjusting the diameter reduction ratio of the reduced diameter portion according to the supply flow rate of the fire extinguishing agent stock solution are provided. An invention has also been proposed in which the fire extinguishing agent concentration can be made constant over a wide range of flow rates by controlling the flow rate of the foam stock solution (Patent Document 2).
However, the fire extinguishing agent mixing device described in Patent Document 2 has a problem that the ability to keep the fire extinguishing agent concentration constant is not sufficient.

The present invention has been made by paying attention to the above-mentioned problems, and an object of the present invention is to provide a foam fire extinguishing system equipped with a mixing device capable of keeping the concentration of the diluted fire extinguishing agent constant for a wide range of flow rates. To provide.
Another object of the present invention is to discharge a constant concentration of diluted fire extinguishing agent from each head even if the number of installed foam emitting heads is different for each section in which the branch pipe branched from the main pipe for sending the fire extinguishing agent is arranged. The purpose is to provide a foam fire extinguishing system that can be used.

In order to solve the above problems, the present invention
Multiple foam emission heads arranged in each compartment in the area,
Water pump and
A first mixer and a second mixer that mix a foam fire extinguisher with the inflowing water, dilute it to a predetermined concentration, and send it out.
A three-way switching valve that has one inlet and two discharge ports and can switch the flow path of water flowing in from the inlet.
A foam fire extinguisher storage tank capable of storing foam fire extinguishing agent and supplying foam fire extinguishing agent to the first mixer and the second mixer.
A first pipe provided between the water pump and the first mixer and the second mixer, and
In a foam fire extinguishing system provided with a first mixer and a second pipe provided between the second mixer and the foam discharge head.
The first mixer is configured to allow more diluted foam fire extinguishing agent to flow out than the second mixer, and one discharge port of the three-way switching valve is set to have a larger cross-sectional area than the other discharge port. The first mixer is connected to the one discharge port, and the second mixer is connected to the other discharge port.

According to the foam fire extinguishing system having the above configuration, a three-way switching valve having one inlet and two discharge ports having different cross-sectional areas automatically opens the flow path by the differential pressure between the inflow port and the discharge port. It can work to switch. Then, the foam fire extinguisher and water are mixed in the mixer by inflowing water through the inflow port of the three-way switching valve and switching the flow path to one of two mixers having different outflow amounts. Since it can be diluted to a predetermined concentration and discharged, the concentration can be kept constant and a mixing device having a large usable flow rate range can be realized.

Further, even if the number of foam discharge heads (foam heads) installed is different for each section in which the branch pipe branched from the main pipe for sending the fire extinguishing agent is arranged, a constant concentration of diluted fire extinguishing agent is applied from each head. You will be able to release it.

Here, preferably, the three-way switching valve is
A cylinder having the one inlet and the two outlets,
A piston that has a space in which water flowing in from the inflow port can flow in and is housed inside the cylinder so as to be movable in the axial direction.
A first orifice plate having a flow passage communicating between the one discharge port and the space of the piston and provided on the side corresponding to the one discharge port.
A second orifice plate having a flow passage communicating between the one discharge port and the space of the piston and provided on the side corresponding to the other discharge port.
An urging means for urging the piston toward the one discharge port, and
The flow passage of the second orifice plate is set so that the flow path resistance is larger than that of the flow passage of the first orifice plate.
According to such a configuration, it is possible to realize a three-way switching valve that operates so as to automatically switch the flow path by the differential pressure between the inflow port and the discharge port with a relatively simple configuration, so that cost increase is suppressed. be able to.

Further, preferably, the flow rate range of the first mixer and the flow rate range of the second mixer are set so as to partially overlap each other.
According to this configuration, by changing the number of heads to be discharged, even if the flow rate changes continuously over a wide range, the foam extinguishing agent diluted to a constant concentration can be supplied to the heads by the two mixers. can.

Further, preferably, the ratio of the minimum flow rate to the maximum flow rate in the flow rate range of the first mixer is configured to be the same as the ratio of the minimum flow rate to the maximum flow rate in the flow rate range of the first mixer. do.
According to this configuration, when designing a mixer for a small flow rate and a mixer for a large flow rate, if one mixer is designed, the other mixer will only be proportionally reduced or expanded in size. Can be easily designed with.

Also, preferably, the foam emitting head is a closed type head.
In foam fire extinguishing equipment using closed foam heads, the number of frequently operating heads changes (increases) compared to foam fire extinguishing equipment using open foam heads, so the flow rate changes continuously over a wide range. Even so, the foam fire extinguishing equipment of the present invention capable of supplying the foam fire extinguishing agent diluted to a constant concentration to the head is extremely effective when applied to a system using a closed foam head.

According to the foam fire extinguishing system of the present invention, the concentration of the diluted fire extinguishing agent can be kept constant for a wide range of flow rates, and a mixing device can be realized. Further, even if the number of foam emission heads installed is different for each section in which the branch pipe branched from the main pipe for sending the fire extinguishing agent is arranged, the effect that the diluted fire extinguishing agent having a constant concentration can be discharged from each head. There is.

In the central sectional view which shows the embodiment of the three-way switching valve which constitutes the fire extinguishing agent mixing apparatus used in the foam fire extinguishing equipment of this invention, (A) shows the state which the flow rate of fire extinguishing water is small, and (B) is fire extinguishing water. Indicates a state in which the flow rate of is large. It is a figure which shows the relationship between the flow rate range of a mixer corresponding to a small flow rate, and the flow rate range of a mixer corresponding to a large flow rate with respect to the usable flow rate range of the whole mixing apparatus of embodiment. It is a system configuration diagram which shows the configuration example when the three-way switching valve of an embodiment is applied to the foam fire extinguishing equipment provided with the closed type foam head. It is a system configuration diagram which shows the configuration example in the case where the three-way switching valve of an embodiment is applied to the foam fire extinguishing equipment provided with the open type foam head. It is a system block diagram which shows the other example of the foam fire extinguishing equipment which provided with the fire extinguishing agent mixing apparatus which consists of a switching valve and a mixer.

Hereinafter, embodiments of the foam fire extinguishing system according to the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional structure of a three-way switching valve constituting the foam fire extinguishing system according to the present invention. FIG. 1A shows a state in which the amount of inflow to the three-way switching valve is small, and FIG. A state in which the amount of inflow to the switching valve is large is shown.
As shown in FIG. 1, the three-way switching valve 10 of this embodiment has a cylinder 11 as a valve body having a bottomed cylindrical shape and a plug 12 that closes an end portion of the cylinder 11 on the opening side (right side in the figure). A piston 14 movably arranged inside the cylinder 11 in the axial direction, and a compression spring 15 for urging the piston 14 to one side (to the right in the figure) are provided. The cylinder 11 is not limited to a cylindrical shape, and may be a square cylinder shape.

A female screw is formed on the inner peripheral surface of the opening side end of the cylinder 11, and the male screw formed on the outer peripheral surface of the plug 12 is screwed into the female screw on the inner peripheral surface of the cylinder 11 to form a cylinder. The plug 12 is coupled to the opening side end of 11.
Further, an inflow port 11a is formed in a portion of the outer peripheral wall of the cylinder 11 corresponding to the space sandwiched between the orifice plates 16A and 16B. Further, the plug 12 is formed with a small flow rate side discharge port 13A, and the bottom wall of the cylinder 11 is formed with a large flow rate side discharge port 13B having a diameter larger than that of the small flow rate side discharge port 13A.

On the other hand, circular orifice plates 16A and 16B are integrally provided at both ends of the piston 14, and the compression spring 15 is interposed between the orifice plate 16A and the plug 12 on the side close to the plug 12. .. An O-ring 17 is inserted between the outer peripheral surface of the cylinder 11 and the inner peripheral surface of the plug 12, and the watertightness between the cylinder 11 and the plug 12 is maintained.

Further, one or a plurality of openings 16a and 16b are formed in the orifice plates 16A and 16B, respectively, and the total cross-sectional area of the openings 16a is set to be smaller than the total cross-sectional area of the openings 16b. .. Further, the orifice plate 16A is formed so as to be thicker than 16B, and the length of the opening 16a is longer than the length of the opening 16b. As a result, the flow path resistance of the opening 16a becomes larger than the flow path resistance of the opening 16b.
The openings 16a and 16b of the orifice plates 16A and 16B are formed at positions facing the outside of the discharge ports 13A and 13B, that is, the inner surface of the plug 12 and the inner surface of the bottom wall of the cylinder 11.

In the three-way switching valve 10 of this embodiment, when the pressure of the liquid flowing in from the inflow port 11a of the outer peripheral wall of the cylinder 11 is smaller than the compressive force of the compression spring 15, as shown in FIG. 1A, The piston 14 is moved to the right and the orifice plate 16B comes into contact with the bottom wall of the cylinder 11 to close the opening 16b. As a result, the liquid that has flowed into the cylinder 11 from the inflow port 11a flows out from the small flow rate side discharge port 12A through the opening 16a of the orifice plate 16A.

On the other hand, when the pressure of the liquid flowing in from the inflow port 11a is larger than the compressive force of the compression spring 15, the piston 14 is moved to the left and the orifice plate 16A is plugged 12 as shown in FIG. 1 (B). The opening 16a is closed in contact with the inner surface of the. As a result, the liquid that has flowed into the cylinder 11 from the inflow port 11a flows out from the large flow rate side discharge port 13B through the opening 16b of the orifice plate 16B. A female screw for screwing the end of the pipe is formed on the inner peripheral surfaces of the inflow port 11a and the discharge ports 13A and 13B.

In this embodiment, as shown in FIG. 2, when the usable flow rate range of the entire mixing device using the three-way switching valve 10 and the mixer is 30 to 600 L / min (liters / minute), the three-way switching valve 10 A mixer having a flow rate range of 30 to 180 L / min is connected to the small flow rate side discharge port 13A for a small flow rate, and for example, a flow rate range 100 is connected to the large flow rate side discharge port 13B for a large flow rate. A mixer of ~ 600L / min is connected. By setting the flow rate range of the mixer corresponding to the small flow rate and the flow rate range of the mixer corresponding to the large flow rate to overlap with each other, it is possible to respond to continuous flow rate changes, and the diameter of the cylinder and the piston 14 can be adjusted. By appropriately setting the stroke amount, a desired flow rate can be obtained even when the piston 14 is moved to a position where the orifice plates 16A and 16B are separated from both the discharge ports 13A and 13B.

Further, in the present embodiment, the ratio of the minimum flow rate to the maximum flow rate in the flow rate range of the mixer corresponding to the small flow rate and the ratio of the minimum flow rate to the maximum flow rate in the flow rate range of the mixer corresponding to the large flow rate are both 6 It is set to double. Therefore, when designing a mixer for a small flow rate and a mixer for a large flow rate, if one mixer is designed, the other mixer can be easily designed by reducing or expanding the dimensions proportionally. can do.

FIG. 3 shows a configuration example of a closed-type foam fire extinguishing system using the three-way switching valve 10 of the above embodiment.
In the foam fire extinguisher equipment shown in FIG. 3, a pump 101 for sending water, a tank 102 for storing the foam extinguishing agent, and water sent by the pump 101 and a foam extinguishing agent supplied from the tank 102 are mixed and diluted. The mixers 103A and 103B, the above-mentioned three-way switching valve 10 provided on the upstream side of the mixers 103A and 103B, and the main pipe 104 for water supply connected between the pump 101 and the mixers 103A and 103B. A pressurized water side pipe 105 branched from the main pipe 104 and connected to the foam fire extinguishing agent storage tank 102, and a fire extinguishing agent side pipe 106 connected between the foam fire extinguishing agent storage tank 102 and the three-way switching valve 10 are provided.

As the mixers 103A and 103B, for example, Venturi type mixers are used, one of which is a small flow rate mixer and the other (103B) is a large flow rate mixer.
The inside of the foam fire extinguishing agent storage tank 102 is separated into a pressurized water region and a fire extinguishing agent region by a diaphragm, and the main pipe 104 passes through the pressurized water side pipe 105 on the inlet side of the three-way switching valve and the foam fire extinguishing agent storage tank 102. The extinguishing agent region of the foam extinguishing agent storage tank 102 is connected to the throttle portion of the mixers 103A and 103B via the extinguishing agent side pipe 106.
A check valve 107, a flexible pipe 108, a sluice valve 109, and the like are provided in the middle of the main pipe 104. Further, a check valve and a sluice valve are also provided in the middle of the pressurized water side pipe 105 and the fire extinguishing agent side pipe 106.

The foam fire extinguishing agent outflow side of the mixers 103A and 103B is arranged in each section via a main delivery pipe 111 for delivering the foam fire extinguishing agent diluted in the mixers 103A and 103B, and a plurality of closed foam heads 112 are provided. It is connected to the branch pipes 113A and 113B having the above. A control valve 114 and a water flow detector 115 are provided in the middle of the main delivery pipe 111.
The outlet of the closed foam head 112 is closed in normal times, and when a predetermined temperature is reached, the heat-sensitive portion operates to open the outlet to release the foam fire extinguishing agent.

Next, the operation of the foam fire extinguishing agent mixing device including the three-way switching valve 10 and the mixers 103A and 103B in the closed type foam fire extinguishing equipment will be described.
Normally, since the pressure of the liquid flowing from the inflow port 11a is low in the three-way switching valve 10, the piston 14 is pressed against the large flow rate side discharge port 13B by the spring restoring force of the compression spring 15, and the large flow rate side discharge port 13B is used. It is closed by the orifice plate 16B.
When running water is generated by the operation of the closed foam head 112, the pump 101 is started by being detected by the flowing water detector 115, and the sent out fire extinguishing water flows into the inflow port 12a of the three-way switching valve 10.

Here, when the number of actuated heads is small and the flow rate is small, the piston 14 is continuously pressed to the large flow rate side by the compression spring 15. As a result, the fire extinguishing water that has flowed into the three-way switching valve 10 flows out from the small flow rate side discharge port 13A via the opening 16a of the orifice plate 16A on the small flow rate side of the piston 14, and the mixer 103A (flow rate) corresponding to the small flow rate. Closed foam disposed in each compartment via the main delivery pipe 111 and branch pipes 113A, 113B as a diluted foam fire extinguishing agent that is mixed with the foam fire extinguishing agent in a range of 30 to 180 L / min) and has an appropriate mixing concentration. It is supplied to the head 112 and discharged.

On the other hand, when the flow rate increases due to the operation of the plurality of closed foam heads 112, and the pressure of the fire extinguishing water flowing in from the inflow port 11a becomes high in the three-way switching valve 10, the piston is beaten by the spring restoring force of the compression spring 15. 14 moves to the small flow rate side, the small flow rate side discharge port 13A is blocked by the orifice plate 16A, and the fire extinguishing water flows out from the large flow rate side discharge port 13B via the opening 16b of the orifice plate 16B on the large flow rate side. As a result, the dilution mixing in the mixer 103A corresponding to the small flow rate is stopped, and the dilution mixing of the foam fire extinguisher is started by the mixer 103B (flow rate range 100 to 600 L / min) corresponding to the large flow rate, and proper mixing is started. It is supplied and released to the closed foam head 112 as a diluted foam fire extinguisher having a concentration.

As described above, the foam fire extinguishing agent mixing device including the three-way switching valve 10 and the mixers 103A and 103B of the present embodiment obtains an appropriate diluted mixture concentration in a wide flow rate range (minimum / maximum flow rate ratio 20 times). Can be done. As a result, even if the fire range is widened and the number of operating foam emission heads is gradually increased, or the number of sections for emitting foam extinguishing agents is increased, a constant concentration of diluted fire extinguishing agent is released from each head 112. be able to.
After extinguishing the fire, the supply of the foam extinguishing agent is stopped by opening the control valve or the like, and when the pressure of the extinguishing water flowing in from the inflow port 11a of the three-way switching valve 10 drops, the piston 14 is again the spring of the compression spring 15. It will be restored to the state of being pressed against the large flow rate side by the restoration power.

FIG. 4 shows a configuration example of a normal non-closed foam fire extinguishing system using the three-way switching valve 10 and the mixer of the above embodiment. The foam fire extinguishing equipment shown in FIG. 4 has almost the same configuration as the closed foam fire extinguishing equipment shown in FIG.
The difference between the foam fire extinguishing equipment shown in FIG. 4 and the closed type foam fire extinguishing equipment shown in FIG. 3 is that in the foam fire extinguishing equipment water of FIG. The open foam heads 116 are connected to each other. Further, in each section, a plurality of sensing heads 117 having a fire sensing function are arranged, and a simultaneous release valve 118 is provided on the starting end side of the branch pipes 113A and 113B.
Then, the sensing head 117 is connected to the simultaneous opening valve 118 via the pipe 119, and when the sensing head 117 detects a fire, the simultaneous opening valve 118 of the corresponding section is opened, and the foam fire extinguishing agent is discharged from the foam head 116. It is released.

The operation of the foam fire extinguishing agent mixing device including the three-way switching valve 10 and the mixers 103A and 103B after the simultaneous release valve 118 is opened is the same as that of the closed type foam fire extinguishing equipment shown in FIG. When a fire breaks out in a section where the number of foam heads 116 installed is small, the piston 14 is pressed to the large flow rate side by the compression spring 15 because the flow rate is small. As a result, the fire extinguishing water flowing into the three-way switching valve 10 flows out from the small flow side discharge port 13A, is mixed with the foam fire extinguishing agent in the mixer 103A corresponding to the small flow rate, and is diluted to have an appropriate mixing concentration. It will be supplied to the foam head 116 as a foam fire extinguishing agent and released.

Further, when a fire breaks out in a section where a large number of foam heads 116 are installed, the piston 14 is pressed against the compression spring 15 to the small flow rate side due to the large flow rate, and the three-way switching valve 10 is reached. The inflowing fire extinguishing water flows out from the large flow side discharge port 13B, is mixed with the foam extinguishing agent in the mixer 103B corresponding to the large flow rate, is diluted, and is diluted to the foam head 116 as a diluted foam extinguishing agent having an appropriate mixed concentration. It is supplied and released.

As described above, the foam fire extinguishing agent mixing device including the three-way switching valve 10 and the mixers 103A and 103B of the present embodiment can obtain an appropriate diluted mixture concentration in a wide flow rate range even in a normal foam fire extinguishing system that is not a closed type. Obtainable. As a result, even if the number of foam discharging heads installed is different for each section in which the branch pipe branched from the main pipe for sending the fire extinguishing agent is arranged, it is possible to discharge the diluted fire extinguishing agent at a constant concentration from each head.
Further, since the three-way switching valve 10 has a simple structure and does not use a solenoid valve, it is possible to reduce the cost of the foam fire extinguishing equipment.
Further, when three types of mixers (small flow rate, medium flow rate, and large flow rate) are used as in Patent Document 1, two of the three-way valve switching valves 10 adapted to each flow rate are prepared. , As shown in FIG. 5, it is possible to correspond to three types of flow rates (mixer) by using them in cascade connection (small flow rate, medium flow rate, and large flow rate).

Although the present invention has been described above based on the embodiment, the present invention is not limited to the above embodiment and can be appropriately modified without departing from the gist thereof. For example, in the above embodiment, it has been described that the foam extinguishing agent storage tank 102 is configured to receive the pressure of the water sent from the water supply pump 101 and supply the foam extinguishing agent to the mixers 103A and 103B. Anything that can supply a foam fire extinguishing agent according to the water pressure of the pump is sufficient.

Further, in the above embodiment, the openings 16a and 16b of the orifice plates 16A and 16B are formed at positions facing the outside of the discharge ports 13A and 13B, that is, the inner surface of the plug 12 and the inner surface of the bottom wall of the cylinder 11. As described above, a part of the opening 16a of the orifice plate 16A and a part of the opening 16b of 16B may overlap with a part of the discharge ports 13A and 13B.
Further, in FIGS. 3 and 4, the three-way switching valve of FIG. 1 in which the flow path is automatically switched by using the differential pressure between the inlet side and the outlet side is used, but the flow rate of each discharge port is configured to be different. If it is, a solenoid valve may be used.

10 Three-way switching valve 11 Cylinder 12 Plug 13A Small flow rate side discharge port 13B Large flow rate side discharge port 14 Piston 15 Compression spring 16A, 16B Orifice plate 101 Pump 102 Foam fire extinguishing agent storage tank 103A, 103B Mixer 112 Closed foam head (foam) Discharge head)
115 Flow detector 116 Open foam head (foam discharge head)
117 Sensing head 118 Simultaneous release valve

Claims (5)

Multiple foam emission heads arranged in each compartment in the area,
Water pump and
A first mixer and a second mixer that mix a foam fire extinguisher with the inflowing water, dilute it to a predetermined concentration, and send it out.
A three-way switching valve that has one inlet and two discharge ports and can switch the flow path of water flowing in from the inlet.
A foam fire extinguisher storage tank capable of storing foam fire extinguishing agent and supplying foam fire extinguishing agent to the first mixer and the second mixer.
A first pipe provided between the water pump and the first mixer and the second mixer, and
A foam fire extinguishing system including a first mixer and a second pipe provided between the second mixer and the foam discharge head.
The first mixer is configured to allow more diluted foam fire extinguishing agent to flow out than the second mixer, and one discharge port of the three-way switching valve is set to have a larger cross-sectional area than the other discharge port. A foam fire extinguishing system, characterized in that the first mixer is connected to the one discharge port and the second mixer is connected to the other discharge port. The three-way switching valve is
A cylinder having the one inlet and the two outlets,
A piston that has a space in which water flowing in from the inflow port can flow in and is housed inside the cylinder so as to be movable in the axial direction.
A first orifice plate having a flow passage communicating between the one discharge port and the space of the piston and provided on the side corresponding to the one discharge port.
A second orifice plate having a flow passage communicating between the one discharge port and the space of the piston and provided on the side corresponding to the other discharge port.
An urging means for urging the piston toward the one discharge port, and
The foam fire extinguishing system according to claim 1, wherein the flow passage of the second orifice plate is set so that the flow passage resistance is larger than that of the flow passage of the first orifice plate. The foam fire extinguishing system according to claim 1 or 2, wherein the flow rate range of the first mixer and the flow rate range of the second mixer are set so as to partially overlap each other. 3. The ratio of the minimum flow rate to the maximum flow rate in the flow rate range of the first mixer is the same as the ratio of the minimum flow rate to the maximum flow rate in the flow range of the first mixer. Foam fire extinguishing equipment described in. The foam fire extinguishing system according to any one of claims 1 to 4, wherein the foam discharge head is a closed type head.

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