JPH114901A - Fire prevention methods - Google Patents

Abstract

(57) [Summary] [Problem] To prevent a fire from occurring in a place where fuel and energy that can ignite it coexist but are always unmanned or in a very dangerous place once a fire occurs, and Realize a safe fire prevention method even if a person enters the room for a short time. SOLUTION: Although the oxygen concentration in the air in a fire prevention chamber 1 is burned by hydrogen or a fuel containing hydrogen in a fuel tank 3 in a combustion chamber 2, a human can breathe. Is reduced to a range that does not last, and that condition is constantly maintained to prevent fire.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fire prevention method for keeping the concentration of oxygen in the air below a certain value and keeping the room indoors at all times so that a fire or explosion does not occur essentially. .

[0002]

2. Description of the Related Art Conventional fire prevention techniques include eliminating a fire, suppressing the energy of the fire to a certain value or less, and when a fire occurs, quickly detect it and extinguish it within a small fire. It was a way to say. However, with conventional methods, it has not been possible to completely prevent a fire or explosion from occurring in an unforeseen accident if energy is used where there is sufficient fuel and oxygen.

[0003]

It is known that when the concentration of oxygen in the atmosphere becomes about 10 to 12% or less, combustion does not occur even if fuel and ignition energy are present. Utilizing this principle, carbon dioxide fire extinguishers have been used in parking lots and the like. However, this method, which has recently been revealed, is not a highly recommended method due to the fact that highly concentrated carbon dioxide is toxic to the human body.

[0004] The carbon dioxide fire extinguisher can extinguish a fire, but at the same time, if a person is present at that place, the disadvantage is that the person also dies. In the past, several painful accidents occurred in the past, when a carbon dioxide fire extinguisher was activated in a parking lot and a person died. Instead of dying from oxygen deficiency, humans die from the toxicity of carbon dioxide. A relatively harmless halon fire extinguishing system was devised for this purpose. However, this has the disadvantage that halon is expensive and that halon pollutes the global environment.

[0005] The present invention is very dangerous in a place where fuel and energy that can ignite coexist but are always unmanned, for example, an automatically operated electrostatic painting factory or a drying room, or once a fire occurs. It is an object of the present invention to provide a fire prevention method that always keeps the indoor state essentially free from fire at a place such as a nuclear power plant, and that is safe even if a human enters for a short time in an emergency.

[0006]

If the concentration of carbon dioxide is reduced and only the oxygen concentration is reduced, even if the oxygen concentration is reduced to less than half, it does not happen that human life is immediately dangerous by itself. Absent. For example, increasing the concentration of nitrogen in the air in a room, thereby reducing the concentration of oxygen to such a degree that combustion does not occur, does not cause the person in the room to die immediately,
Some activity is possible. Even if the oxygen concentration is 9 to 14%, human beings are not able to judge or become uplifted, but they do not die within a few minutes, but the concentration of carbon dioxide gas is 10%. If you do, you will die within minutes.

On the other hand, when the oxygen concentration becomes about 10%, the flame is extinguished or the fire loses its momentum. In other words, it has the effect of fire prevention. Generally speaking, if the concentration of carbon dioxide in the indoor air is kept within 5% and the oxygen concentration is kept above 10%, short-term human activities in the room are possible and fire The effect of prevention is demonstrated.

The present invention provides several means for reducing oxygen concentration in a manner that balances life safety and fire suppression, and provides a means of sustaining the environment achieved by these means. The first measure is to burn hydrogen or a fuel rich in hydrogen, while suppressing the increase in carbon dioxide gas.
In this method, oxygen in the air is consumed by combustion to reduce the oxygen concentration.

The second means is a method of reducing oxygen concentration by adsorbing oxygen in air using an oxygen adsorbent. A third measure is to provide a device for preventing excessive reduction of oxygen in the room to ensure the safety of human life.

A fourth means is a partially open room, a method of preventing mixing of reduced oxygen air with external air in order to maintain the low oxygen concentration achieved by such means. It is to take.

[0011]

FIG. 1 shows a typical embodiment of the first means of the present invention. 1A is a plan view of a fire prevention room, and FIG. 1B is a side view of the fire prevention room, 1 is a fire prevention room, 2 is a combustion room, 3 is a fuel tank, 4 is a burner for burning fuel,
Reference numeral 5 denotes an ignition device, reference numeral 6 denotes a fuel cock, reference numeral 7 denotes an intake port of the combustion chamber 2, reference numeral 8 denotes an exhaust port of the combustion chamber 2, reference numeral 9 denotes an automatic intake valve connected to outside air attached to the intake port 7, and reference numeral 10 denotes an inside of the combustion chamber 2. Mesh to prevent the flame of the fire from igniting the fuel in the fire prevention room 1, 11
Is an air discharge valve provided in the lower part of the fire prevention room 1, and 12 is a combustion detector.

The fuel tank 3 contains hydrogen or a fuel containing a large amount of hydrogen. The fuel is supplied to the burner 4 through a fuel cock 6. The fuel is ignited by an ignition device 5 and burns on the burner 4. When hydrogen is used as fuel, oxygen becomes water vapor, so that oxygen can be reduced without increasing harmful carbon dioxide gas. The combustion chamber 2 is usually provided below the fire prevention room. This is because the exhaust from combustion is light and goes upward. The air in the fire prevention chamber 1 enters the combustion chamber 2 from the intake port 7 and supplies oxygen to the burner 4.
Air containing oxygen and water vapor generated by the combination of hydrogen and oxygen due to combustion is exhausted from the exhaust port 8 into the fire prevention room 1.

A wire mesh 10 is attached to the inlet 7 and the outlet 8 so that the flame of the burner 4 does not ignite flammable gas that may be in the fire prevention chamber 1 outside the combustion chamber 2. This wire mesh is a method used in coal mines to prevent ignition when using a flame lamp in places where flammable gas is present.

The oxygen in the fire prevention room 1 is consumed by the combustion of hydrogen, and the oxygen concentration in the room decreases. In the case of a closed chamber, when about 10% of oxygen, which is half of about 20% of oxygen contained in air by burning hydrogen, is consumed by combustion of hydrogen, combustion is almost immediately stopped due to lack of oxygen. It becomes impossible.

The burned hydrogen combines with oxygen to form steam. If the temperature of the room or the temperature of the wall of the room is low, the water vapor saturates and liquefies into water, so that the air pressure is reduced accordingly.
Automatic intake valve 9 to keep the air pressure inside and outside the room balanced
Works and air enters from the outside of the fire prevention room 1 to balance the air pressure. In such a case, the hydrogen must be further burned.

Conversely, when the room temperature is high enough not to liquefy the water vapor, one molecule of oxygen is burned to become two molecules of water vapor, so the indoor pressure increases. It is not preferable that the air pressure in the fire prevention room 1 rises too much. In this case, the air in the room must be released. Therefore, when the pressure in the fire prevention room 1 becomes higher than the outside pressure, the air discharge valve 1 automatically discharges the room air to the outside.
1 is provided.

Since the water vapor is light and tends to accumulate on the ceiling of the room, the air discharge valve 11 is preferably installed at the lower part of the room. In this case, the excess air flows out from the lower part of the room, so that the air containing a large amount of oxygen goes out, and instead the water vapor accumulates in the room, so that the oxygen concentration can be reduced quickly. For the above reasons, when consuming oxygen with a fuel containing hydrogen, it is desirable to raise the temperature in the room so that the generated water vapor does not liquefy and become water. When replacing half of the oxygen in normal air with water vapor, it is desirable to maintain the room temperature at 50 ° C. or higher.

Almost the same purpose can be achieved by using a hydrogen-rich fuel such as methane or butane or methanol or ethanol instead of pure hydrogen. For example, burning one molecule of ethanol reduces two molecules of oxygen in the air, and instead produces one molecule of carbon dioxide and three molecules of water vapor. By burning such a fuel that also contains carbon but contains a lot of hydrogen, the oxygen concentration can be reduced to a level sufficient for fire prevention before the concentration of carbon dioxide becomes a concentration that is dangerous to human life. .

Of course, in this case, too, water vapor is generated, so that it is desirable to keep the room temperature high. If the carbon dioxide gas generated in this case is adsorbed using a carbon dioxide adsorbent, the degree of safety is further improved.

When the oxygen concentration in the room becomes lower than a certain level, the combustion of hydrogen is automatically stopped. Therefore, the supply of hydrogen must be stopped immediately after the flame of hydrogen is extinguished so that an explosion due to hydrogen gas does not occur. Must. For this purpose, a combustion detector 12 for detecting whether or not combustion is continuing is provided. When the combustion stops, the combustion detector 12 operates to detect the stop of the combustion, and the fuel cock 6 operates to stop the supply of fuel to the burner 4 to prevent an accident such as an explosion. When using hydrogen as a fuel, automatic stoppage of fuel is an important operation, because if unburned hydrogen is supplied in excess, there is a risk of explosion.

When the temperature in the fire prevention room 1 is low and water vapor adheres to the walls of the room, etc., the air pressure in the room is reduced. Works to take in air from outside. In this case, a mixture of indoor air and outdoor air is supplied to the combustion chamber 2. If such a process is continued for a long time, oxygen in the room is replaced with nitrogen.

The combustion chamber 2 may be provided inside the fire prevention chamber 1 or may be provided outside through a duct. FIG. 2 is a side view showing an example of a duct provided outside the fire prevention room 1, and 21 indicates a duct. Since the method of reducing oxygen by combustion uses oxidative combustion by itself, the combustion stops automatically when oxidative combustion proceeds to some extent. In order to further reduce the oxygen concentration, a nonflammable gas, for example, nitrogen or an inert gas such as argon, which has been conventionally used, is used.
A method of replacing the air in the target room or using the second means is also used.

The second means is a method of placing a substance which selectively adsorbs oxygen in a target room. FIG. 3 shows an embodiment of a fire prevention method according to the second means. In FIG. 3, reference numeral 31 denotes an oxygen adsorbent placed in the combustion chamber 2 in the duct 21. What is generally called a reducing agent is suitable as the oxygen adsorbent as the oxygen adsorbent 31. The most common of these is metal powder. Powdered metal that has an increased area in contact with air is easily oxidized, and the heat generated during the oxidation is used in portable hand warmers. The oxygen adsorbent 31 is put together on a well-ventilated shelf in a well-ventilated storage method.

Although the air is warmed by the heat generated during the oxidation of the adsorbent and the ventilation in the duct 21 is performed, the ventilation may be forcibly performed. And fire prevention room 1 by oxidation
Although the oxygen in the interior of the fire prevention room 1 decreases due to the decrease in the oxygen, the outside air is taken in by the automatic intake valve 9 to adjust the air pressure.

When the oxygen adsorbent 31 is oxidized, heat is generally generated. Therefore, a wire mesh 10 for preventing ignition is provided so as not to cause the ignition. Unlike the case of fuel combustion, the oxygen adsorbent 31 has an oxygen concentration of 10
Since the oxygen may still be adsorbed even when divided by%, a third measure is taken so as not to bring about a decrease in oxygen enough to make short-time human activity impossible.

FIG. 4 is a diagram showing an embodiment of the third means. In FIG. 4, reference numeral 41 denotes an oxygen concentration measuring device. Reference numeral 42 denotes an automatic shutter that operates in accordance with the magnitude of the concentration indicated by the oxygen concentration measuring device 41, automatically operates when the oxygen concentration reaches a predetermined value, and controls the air flow from the fire prevention chamber 1 to the combustion chamber 2 A shutter that blocks the passage. When the oxygen concentration reaches a predetermined value, typically 10%, the shutter 42 closes and blocks the flow of air between the combustion chamber 2 and the fire prevention chamber 1. The operation of the shutter 42 prevents the oxygen from further decreasing. When the shutter 42 operates, the supply of air to the burner 4 is stopped, so that combustion in the burner 4 becomes impossible, although there is some time delay. When the burner 4 stops burning, the combustion sensor 12
Operates to stop the fuel cock 6 from supplying fuel, thereby preventing a disaster such as an explosion due to excessive fuel supply.

The fourth means is a means for preventing mixing of the air in the room, in which the concentration of oxygen has been once lowered, with the outside air rich in oxygen. In a closed room, there is no problem because there is no air exchange, but in a semi-open room, such as a room where goods always enter and leave, in a semi-open room, the air in the room with reduced oxygen concentration and the normal outside air I want to reduce the interaction with as much as possible.

As a fourth means, air curtains are provided in multiple stages in the room, as a fourth means, as well as to make the entrance of the minimum size suitable for the goods entering and exiting the room. FIG. 5 is a diagram showing an embodiment using an air curtain of the fourth means. 5
1 is an air outlet, 52 is a suction port, 53 is a blower, 54 is a curtain, 55 is a belt conveyor, and 56 is a product that enters and exits the fire prevention room 1 on a belt conveyor. A plurality of outlets 51 and inlets 52 are provided alternately on the ceiling surface and the floor surface, respectively, and a pair of upper and lower sides forms an air curtain.

The air curtain may be blown out from the ceiling and sucked out from the floor, or the air may flow in the opposite direction. When providing a plurality of air curtains, two air curtains adjacent to each other are installed so that the directions of the winds are opposite. In this way, the air in the room between the two air curtains, the air that was sucked into the air curtain and the air that was not sucked together, swirled up and down and constantly rotated To be.

The air sucked from the suction port 52 of the air curtain is blown out from the blowing port 51 of the adjacent air curtain. As indicated by the arrows in FIG. 5, the air curtains 51 and 52 and the curtain 54 work together to rotate the air in the fire prevention room 1 at the same place to prevent mixing of the air inside and outside, thereby preventing the fire prevention room 1 from mixing. 1 serves to maintain the state of air having a low oxygen concentration. The curtain 54 is a normal curtain made of cloth or plastic, and is provided for the purpose of allowing goods to pass therethrough but blocking other parts to prevent air flow. The air curtain and the curtain 54 prevent the fire prevention room 1 and the outside air from interacting together.

[0031]

According to the present invention, since the concentration of oxygen in a room can be reduced while suppressing the generation of carbon dioxide harmful to the human body, a fire can be prevented, and a room can be safely entered for human inspection. It is possible to get a preventive method,
The effect on disaster prevention is great.

[Brief description of the drawings]

FIG. 1A is a plan view showing an embodiment of the present invention, and FIG.

FIG. 2 is a side view showing an example of a duct.

FIG. 3 is a diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram showing a third embodiment of the present invention.

FIG. 5 shows a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fire prevention room 2 Combustion chamber 3 Fuel tank 10 Wire mesh 31 Oxygen adsorbent 41 Oxygen concentration measuring instrument 42 Shutter 51 Blow-out port 52 Suction port 53 Blower

Claims (8)

[Claims] 1. A fire prevention method characterized by reducing the oxygen concentration in the air in a fire prevention room to a range in which humans can breathe but not burn, thereby suppressing the fire. 2. The fire prevention method according to claim 1, wherein the oxygen concentration is reduced without increasing the carbon dioxide gas. 3. The fire prevention method according to claim 1, wherein the oxygen concentration is reduced to a range of 9 to 12%. 4. The method according to claim 1, wherein the oxygen in the fire prevention chamber is consumed to reduce the oxygen concentration by burning hydrogen or a fuel containing a large amount of hydrogen in the combustion chamber provided with a means for preventing ignition. Fire prevention method according to any of the above. 5. The fire prevention room, wherein air in the fire prevention room is circulated to the combustion chamber in which the oxygen adsorbent is accumulated, and oxygen is adsorbed by the adsorbent to lower the oxygen concentration in the fire prevention room. The fire prevention method according to any one of claims 1 to 3. 6. The fire prevention method according to claim 5, wherein the adsorbent is a reducing agent. 7. A device for monitoring the oxygen concentration in a fire prevention room, and a device for interlocking with the device for preventing the oxygen concentration from becoming too low. The fire prevention method according to any one of claims 4 to 6, wherein an air passage leading from the air to the combustion chamber is shut off. 8. The fire prevention room according to claim 1, wherein a plurality of air curtains are provided in the fire prevention room to prevent an exchange between air in the fire prevention room and air outside the room. The fire prevention method described.