JP2007222534A - Fire extinguishing/preventing device, and fire extinguishing/preventing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fire extinguishing/preventing device and a fire extinguishing/preventing method for preventing quick spread of burning in a compartment fire and efficiently preventing the fire in a short period of time. <P>SOLUTION: An air compressor 1 takes in air in the atmosphere and compresses the air. The compressed air in the air compressor 1 is fed to a nitrogen separating membrane unit 3 by opening an open/close valve 2. The fed compressed air is separated by the nitrogen separation membrane unit 3 to oxygen-enriched air and NEA (nitrogen-enriched air), and the separated NEA is fed to an NEA nitrogen concentration control device 4. The flow rate of NEA is adjusted by an electromagnetic flow adjusting valve 4a inside the NEA nitrogen concentration control device 4. At the same time, the oxygen concentration in air forced out of the compartment is measured by an outside oxygen sensor 6 and a compartment oxygen concentration measuring device 7, and the measured oxygen concentration is inputted in a flow control box 4b. The flow control box 4b controls the electromagnetic flow adjusting valve 4a based on the inputted value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

 The present invention relates to a fire extinguishing / fire prevention device and a fire extinguishing / fire prevention method for preventing the occurrence of rapid combustion expansion in a compartment fire.

 When a fire occurs in a completely sealed compartment, unless the compartment is destroyed, the internal oxygen concentration continues to decrease due to combustion, leading to natural fire extinguishing. On the other hand, it is common for some buildings to have some openings. In such a fire in a compartment that is provided with a relatively small opening and a small amount of air continues to flow in the event of a fire, there is a phenomenon in which combustion in the compartment rapidly expands in the course of the fire. At that time, the rising pressure destroys the compartment, and there is a risk that people who are active around it will be damaged. Regarding the above-mentioned compartment fire, a water spray fixed fire extinguishing facility as shown in Patent Document 1 has been presented. However, this method requires prior installation of the facility, and an effect cannot be expected in a space with many watering obstacles.

In particular, in a fire in a closed section where a large amount of combustible material is stored, external air may flow in or flammable gas may be generated by water injection for extinguishing. Explosion accidents that seem to be the cause often occur. On August 19, 2003, two firefighters were killed by the explosion in a fire that occurred in the RDF storage in Mie Prefecture (see Non-Patent Document 1). In the fire of a garbage disposal machine that occurred at a supermarket in Yamato City, Kanagawa Prefecture on November 5, the same year, 11 firefighters and others were seriously injured (see Non-Patent Document 2). Because there are many such cases, the US Federal Crisis Management Agency (FEMA) sounded a warning that water and bubbles should not be used to extinguish this type of fire (see Non-Patent Document 3).
Thus, current water-based fire extinguishing equipment not only does not prevent the occurrence of the sudden expansion of combustion during a compartment fire, but it may also induce it.

FIG. 2 shows changes in temperature, oxygen concentration, and the like at the time of occurrence of rapid combustion expansion measured in an experiment of burning wood cribs in an 8 m ³ section conducted by the applicant of the present application. From this experimental result, it can be seen that the conditions for the rapid expansion of combustion are as follows.
(1) Flameed combustion in the compartment stops due to a decrease in oxygen concentration or the like.
(2) There is a high temperature range in combustible materials and thermal decomposition continues.
(3) The oxygen concentration in the compartment is maintained at a constant level by the inflow of external air.
If all of the above three conditions are met, there is a possibility that sudden expansion of combustion may occur. Therefore, removing any of these conditions is effective for suppressing generation.

When viewing the above three conditions from the viewpoint of fire fighting activities, condition (1) is advantageous for fire fighting activities, and condition (2) is difficult to control outside the compartment. It is desired to suppress the rapid expansion of combustion by not satisfying (3). As a technique related to this, there is known a conventional technique in which air with a high nitrogen concentration is injected into a compartment to reduce the oxygen concentration in the compartment and extinguish the fire.
JP 2002-017883 A Fire Magazine Editorial Subcommittee, “Large-scale fires that occurred in August and September 2003”, Fire, Vol.53, No.5, p.5-7, (2003.10) Fire Magazine Editorial Subcommittee, “Fire News”, Fire, Vol. 53, No. 6, p. 67, (2003.12) Suzuki, “About Silo Fire”, Fire, Vol.55, No.2, p.35-41, (2005.4)

 When the above sudden combustion expansion phenomenon occurs, there is a danger that the compartment will be destroyed by the suddenly rising pressure, and the people around the compartment will be damaged. Extinguishing fires efficiently in time was an important issue for fire fighting activities.

 The present invention has been made to solve such a problem, and provides a fire extinguishing / fire prevention device and a fire extinguishing / fire prevention method capable of preventing combustion sudden expansion of a compartment fire and efficiently suppressing combustion in a short time. Objective.

 The present invention has been made to solve the above problems, and the invention according to claim 1 includes a nitrogen-enriched air generating means for generating nitrogen-enriched air having a higher nitrogen concentration than air in the atmosphere, and Adjusting means for adjusting the nitrogen concentration of the nitrogen-enriched air, inflow means for flowing the adjusted nitrogen-enriched air into the compartment, and external oxygen concentration measuring means for measuring the oxygen concentration of the air discharged from the compartment And a flow rate control means for controlling the adjusting means based on the oxygen concentration.

 The invention according to claim 2 is characterized in that the first flow rate control means controls the adjusting means so as to increase the nitrogen concentration of the nitrogen-enriched air stepwise. It is a fire extinguishing / fire prevention device described.

 The invention according to claim 3 is a first step of generating nitrogen-enriched air having a higher nitrogen concentration than air in the atmosphere, a second step of measuring the oxygen concentration of air discharged from the compartment, And a third step of adjusting the nitrogen concentration of the nitrogen-enriched air based on the oxygen concentration measured in the second step to flow into the compartment.

 The invention according to claim 4 is the fire extinguishing / fire prevention method according to claim 3, wherein the third step adjusts the nitrogen concentration of the nitrogen-enriched air stepwise. is there.

 The flow rate control means includes an external oxygen concentration measuring means for measuring the oxygen concentration of the air discharged from the compartment, and a control means for controlling the adjusting means based on the oxygen concentration. And a fire extinguishing / fire prevention device according to claim 1 or 2.

 ADVANTAGE OF THE INVENTION According to this invention, while preventing the generation | occurrence | production of combustion rapid expansion in division fire, it becomes possible to suppress fire efficiently in a short time.

 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of a fire extinguishing / fire prevention device in the present embodiment. 1 includes an air compressor 1 that compresses air, an on-off valve 2 that adjusts the supply amount of air compressed by the air compressor 1, and nitrogen and oxygen in the compressed air. And a nitrogen separation membrane unit (corresponding to a nitrogen-enriched air generating means) 3 for generating NEA (Nitrogen Enriched Air), and a NEA nitrogen concentration control device for adjusting the nitrogen concentration of NEA 4, an oxygen concentration meter 5 that measures the oxygen concentration of NEA that is output from the NEA nitrogen concentration control device 4, an external oxygen sensor 6 that detects oxygen in the air pushed out from or inside the compartment, and from the compartment It is comprised from the division oxygen concentration measuring apparatus 7 which measures the oxygen concentration in the extruded air.

 The NEA nitrogen concentration control device 4 includes an electromagnetic flow rate adjustment valve (equivalent to an adjustment means and an inflow means) 4a for adjusting the flow rate so that the oxygen concentration of NEA becomes a predetermined concentration, and an output of the compartment oxygen concentration measurement device 7. The flow rate control box (corresponding to the flow rate control means) 4b is configured to send a command to the electromagnetic flow rate control valve 4a so as to change the oxygen concentration of NEA to a predetermined value. The electromagnetic flow rate adjusting valve 4a controls the flow rate of NEA flowing from the nitrogen separation membrane unit 3 so that the nitrogen concentration of NEA increases (the oxygen concentration decreases).

 Next, the operation of the fire extinguishing / fire prevention apparatus of the present embodiment will be described below. The air compressor 1 takes in air in the atmosphere and compresses it. The compressed air in the air compressor 1 is sent to the nitrogen separation membrane unit 3 by opening the opening / closing valve 2. In the nitrogen separation membrane unit 3, the supplied compressed air is separated into oxygen-enriched air and NEA, and NEA is passed through the NEA nitrogen concentration controller 4. The flow rate control box 4b in the NEA nitrogen concentration control device 4 adjusts the flow rate of NEA by means of the electromagnetic flow rate control valve 4a so that NEA becomes the set oxygen concentration of 12% in the first step.

 At the same time, the external oxygen sensor 6 and the compartment oxygen concentration measuring device 7 are used to measure the oxygen concentration in the air pushed out of the compartment and input it to the flow control box 4b. When the oxygen concentration input to the flow rate control box 4b reaches a predetermined value, the flow rate control box 4b issues a command to the electromagnetic flow rate adjustment valve 4a, and the NEA injected into the compartment is the oxygen concentration set in the second step. The flow rate of NEA is gradually reduced to 10%. The NEA adjusted by the electromagnetic flow rate adjusting valve 4 a is sent into the compartment through the oximeter 5. The oxygen concentration meter 5 measures the NEA oxygen concentration and feeds it back to the flow rate control box 4b in order to check whether the adjusted NEA oxygen concentration is in accordance with the adjustment.

 As described above, the flow rate and oxygen concentration of NEA injected into the compartment can be optimally adjusted. Therefore, by gradually reducing the oxygen concentration of NEA injected into the compartment, a separation membrane device having the same capacity generates NEA with a larger flow rate, effectively preventing the inflow of fresh air from the outside. Can be prevented. As a result, the oxygen concentration in the compartment can be lowered efficiently, so that it is possible to prevent the sudden expansion of the combustion of the compartment fire and to efficiently suppress the combustion in a short time.

 FIG. 3 is a diagram showing the relationship between the nitrogen concentration of NEA generated by a certain nitrogen separation membrane unit product and the flow rate of NEA. FIG. 3 shows measured values under conditions of a temperature of 25 ° C. and a pressure of 0.7 MPa. As described above, the nitrogen separation membrane is a membrane unit having the same ability, and the lower the nitrogen concentration of the product gas NEA (closer to air), the greater the flow rate of NEA. Therefore, in the case where NEA having a low oxygen concentration is injected from the initial stage of injection by injecting NEA having a low oxygen concentration (high nitrogen concentration) stepwise according to the oxygen concentration in the compartment as in the above embodiment. It can be confirmed that there is an effect of reducing the oxygen concentration in the compartment to the target value in a short time compared to.

 FIG. 4 shows the relationship between the nitrogen concentration of NEA injected into the compartment by the nitrogen separation membrane, the injection time until the target concentration (hereinafter referred to as the set oxygen concentration) is achieved, and the flow rate of NEA that can be supplied from the nitrogen separation membrane. As the nitrogen concentration of NEA injected into the compartment increases, the flow rate of NEA decreases. In addition, when NEA of each nitrogen concentration is injected, the injection time until each set oxygen concentration (12.5%, 15%, 17%) is achieved takes a minimum value at different nitrogen concentrations. Therefore, it can be confirmed that it is efficient to increase the nitrogen concentration of NEA stepwise as indicated by the thick line L in order to quickly reduce the oxygen concentration in the compartment.

 In addition, as an application example of the fire extinguishing / fire prevention device of this embodiment, the fire extinguishing / fire prevention device of this embodiment is mounted on a self-propelled vehicle such as a fire engine, and in addition to the fire extinguishing / fire prevention device of this embodiment, NEA is installed. The NEA injection hose for injecting into the compartment and a monitoring device for monitoring the status of the fire space such as temperature, pressure and smoke can be utilized in combination. Here, the engine of a self-propelled vehicle such as a fire truck is used as a power source, and NEA is produced from air in the atmosphere and injected into the compartment.

 By using the configuration of the above utilization example, when a fire occurs in a warehouse or the like that stores solid combustibles, the fire truck of this utilization form quickly moves to the site to obtain the necessary oxygen concentration (for example, 12%) The adjusted NEA can be produced at the fire site, and a required amount of NEA can be sent into the compartment from the opening of the compartment such as a warehouse. In addition, when the oxygen concentration in the compartment is reduced to the target value and there is no danger of sudden expansion of combustion, the after-fire is extinguished with water or the like.

It is a block diagram which shows the structure of the fire-extinguishing and fire prevention apparatus concerning embodiment of this invention. It is a figure which shows the change of the temperature at the time of generation | occurrence | production of the rapid combustion expansion in an in-compartment combustion experiment, oxygen concentration, etc. It is a figure which shows the relationship between the nitrogen concentration in NEA in a nitrogen separation membrane, and the flow volume of NEA. It is the figure which showed the relationship between the nitrogen density | concentration in NEA inject | poured into a division by a nitrogen separation membrane, and the injection | pouring time and flow volume of NEA.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Air compressor, 2 ... Open / close valve, 3 ... Nitrogen separation membrane unit, 4 ... NEA nitrogen concentration control device, 5 ... Oxygen concentration meter, 6 ... External oxygen sensor, 7 ... Compartment oxygen concentration measuring device, 4a ... Electromagnetic type Flow control valve, 4b ... Flow control box

Claims (5)

A nitrogen-enriched air generating means for generating nitrogen-enriched air having a higher nitrogen concentration than air in the atmosphere;
Adjusting means for adjusting the nitrogen concentration of the nitrogen-enriched air;
Inflow means for flowing the adjusted nitrogen-enriched air into the compartment;
Flow rate control means for controlling the adjusting means based on the oxygen concentration of the air discharged from the compartment;
Fire extinguishing and fire prevention device characterized by comprising  2. The fire extinguishing / fire-fighting apparatus according to claim 1, wherein the first flow rate control unit controls the adjustment unit to increase a nitrogen concentration of the nitrogen-enriched air in a stepwise manner. A first step of generating nitrogen-enriched air having a higher nitrogen concentration than air in the atmosphere;
A second step of measuring the oxygen concentration of the air exhausted from the compartment;
A third step of adjusting the nitrogen concentration of the nitrogen-enriched air based on the oxygen concentration measured in the second step to flow into the compartment;
Fire extinguishing / fire prevention method characterized by comprising.  The fire extinguishing / fire prevention method according to claim 3, wherein the third step adjusts the nitrogen concentration of the nitrogen-enriched air in a stepwise manner. The flow rate control means includes an external oxygen concentration measuring means for measuring the oxygen concentration of air discharged from the compartment,
Control means for controlling the adjusting means based on the oxygen concentration;
The fire extinguishing / fire prevention device according to claim 1 or 2, characterized by comprising:

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