JP3131489B2 - Fire detection method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting a fire, and more particularly to a method and an apparatus for detecting a fire capable of accurately detecting a specific substance generated at the time of an initial fire. Things.

[0002]

2. Description of the Related Art Conventionally, as a method of detecting a fire, a method of monitoring heat and smoke in a monitoring area and discriminating a fire when a predetermined threshold value or a rising rate is reached is generally used. If you are trying to find a fire in a computer room or a room with semiconductor manufacturing equipment, stretch the sampling pipe to collect air inside the room, and use a particle counter or dust monitor to monitor the air in the sampled air. A fire was detected based on the light reflection of the particles. However, the detection method based on the light reflection of the air particles as described above often causes misinformation due to dust. In recent years, it has been necessary to detect fires before they become important due to the combustion gas and smell generated in the initial fire, especially the smoldering fire (a state in which smoke is not observed at a temperature of about 200 ° C and only a burning smell is generated). For example, a method of detecting a fire based on a change in the resistance value of a semiconductor element due to these released gases is being studied.

[0003]

However, in the above method, it is difficult to selectively detect only the smell at the time of the initial fire. SUMMARY OF THE INVENTION It is an object of the present invention to solve the conventional problems as described above and to provide a fire detection method and apparatus capable of accurately detecting a fire, particularly a specific substance generated at the time of an initial fire.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors were able to solve the above-mentioned conventional problems. That is, a first aspect of the present invention is to ionize air sampled from a monitored area, accelerate the air, fly a certain distance, measure the flight time, and measure the measured flight time by at least one of the fire-generated times. It is an object of the present invention to provide a fire detection method, characterized in that a fire is determined when a flight time of a substance measured under the same conditions as above is determined. The second aspect of the present invention is that a fire caused in advance by a fire 1
More than one substance is ionized, accelerated, fly a certain distance, measure the flight time, register the obtained flight time in the registration means, and measure the flight time of the air sampled from the monitored area. Measuring under the same condition, comparing the flight time with the flight time of the substance registered in the registering means, and determining that the fire occurs when at least one of the two flight times coincides with each other; It provides a detection method. A third aspect of the present invention is an ionizing means for ionizing air sampled from a monitoring area, an accelerating means for accelerating an air component ionized by the ionizing means, and measuring a flight time of a constant distance of the accelerated air component. Detecting means, a registering means capable of registering one or more flight times of a substance generated by a fire, and comparing the flight time detected by the detecting means with the flight time registered in the registering means. And a discriminating means for discriminating a fire when at least one of the two flight times coincides with each other.

Hereinafter, the present invention will be described in more detail. The present invention is to detect an initial fire, particularly a smoldering fire, with very high accuracy by measuring a specific substance generated at the time of an initial fire using a mass spectrometer.

In the present invention, means for detecting a specific substance generated in an initial fire can be generally performed using a mass spectrometer, particularly a TOF (Time of Flight) mass spectrometer. Normally, a TOF mass spectrometer is composed of an ionization unit, a flight unit, and a detection unit.

In the present invention, the air sampled from the monitored area is first ionized in the ionization section. The ionization performed in the ionization unit can be performed by various methods. Among them, an atmospheric pressure ionization method, which is a so-called soft ionization method, in which ⁶³ Ni is used, and a sample is ionized by β rays emitted from the Ni, is used. It is suitable because various air components can be analyzed. Subsequently, the ionized air component is accelerated in the flight section. The acceleration can be performed by various methods. For example, a method in which a voltage is applied in a pulsed manner between two electrodes to accelerate the electrodes and the like can be given. The time of flight of the ionized and accelerated air components depends on the mass thereof, and the time of flight is measured for each component by a detector in the detecting means. The detector of the detecting means used in the present invention is actually a collecting electrode, but is not particularly limited, and various types can be used.

Subsequently, T which can be used in the present invention
An example of an OF mass spectrometer will be described with reference to the drawings. FIG.
FIG. 3 is a diagram schematically illustrating an example of an ionization unit and a flight unit of the TOF mass spectrometer. The air introduced from the sampling pipe 17 is first ionized by the ionization unit 18.
A voltage is applied between the collecting electrode 22 and the counter electrode 23 in a pulsed manner, and the ionized air component is accelerated by the electric attraction at that time. The accelerated air component reaches the collecting electrode 22 while being narrowed down by the focus ring 21 through the flight section 20. In this case, the flight time of a certain distance from the counter electrode to the collecting electrode is detected by the detector. Is done.

The fire detection according to the present invention can be performed as follows. First, the TOF mass spectrometer measures in advance the flight time of a substance (sunk substance) which is considered to be easily sunk by the initial fire, and registers the obtained flight time in the registration means. Similarly, the time of flight of the air component (sample gas) sampled from the monitored area is measured, and when this matches at least one of the times of flight registered in the registration means, the fire is determined by the determination means.
Since the flight time is affected by the ambient temperature and atmospheric pressure, in order to correct this, a gas of a reference substance (reference gas) is mixed into the sample gas, and the mixture is applied to a TOF mass spectrometer. Preferably, a difference or a ratio between the respective flight times is calculated, and this value is registered in the registration means. Of course, similarly, the flight time of the smoked substance is corrected and registered in the registration means. In the embodiments described below,
Two reference gases, namely, TNT and cocaine gases, were mixed, but in addition to these reference gases, preferred reference gases include naphthalene and the like. However, the molecular weight is large, the vapor pressure is stable,
There is no particular limitation as long as it is physically stable.

FIG. 2 is a block diagram of a fire detecting device according to the present invention.
It was shown to. In FIG. 2, 1 is a microprocessor MP
U, 2 is a ROM in which a program for detecting a fire is stored, 3 is a ROM, in which a substance name of combustibles and data relating thereto are stored, 4 is a flight time M corresponding to the substance name in the ROM 3, A ROM in which the number N is stored, 5 is a working RAM, and 6 is an R for storing a substance name to be monitored.
AM and 7 are TOF mass spectrometers 1 by the data analysis unit 10.
RAM for storing the peak value selected from 1, 8
Is an indicator such as a display (an alarm unit such as a buzzer may be provided), 9 is an operation unit such as a numeric keypad or a reader, and 10 is data that is processed from the TOF mass spectrometer 11 and only required flight time A data analysis unit to be selected; 11, a TOF mass spectrometer having a sampling tube 17; 12, a signal transmission / reception unit including a serial-parallel converter for transmitting a signal to a fire receiver or the like (not shown); 13, 14, 1
Reference numerals 5 and 16 are interfaces.

FIG. 3 shows the contents stored in the ROM 3 and the ROM 4. Basically, the substance name is stored in the ROM 3 and the flight time is stored in the ROM 4. For example, in the ROM 3, the number A of the substance A and its flight time N
ROM 4 in which ₁ and flight times M ₁₁ , M ₁₂ ,... Are stored.
Is the leading address AD ₁ is stored in similarly, the head address AD ₂ of the material B and the number N ₂ of the flight time flight time M _21, M _22, · · · are stored, substance C and the start address AD _3, substance D and the leading address AD _4, etc. are stored. The ROM 4, first time of flight number N ₁ at the address AD ₁ is, is then flight time M _11, M ₁₂ · · · are stored, the number N ₂ of the flight time to the position of the subsequent address AD ₂ The flight times M ₂₁ , M ₂₂ ... Are stored. Similarly, the number N of the flight times and the flight time M are continuously stored for the substance in the ROM 3.

FIG. 4 and FIG.
Shows a flowchart of a program to be incorporated in the program. First, it is assumed that the variable R has been reset to 0 in advance. When the substance stored in the ROM 3 is designated from the operation unit 9, YES is determined in step S1, the variable R is incremented, and the number R of the designated substance is set (S2). The substance stored in the ROM 3 is read from the operation unit 9 and the contents are stored in the RAM 6 (S
3). Steps S2 and S3 are repeated each time designation is performed. When the designation is completed, NO in step S1
Is read, and all the peak values detected by the mass spectrometer 11 are read from the data analysis unit 10 and stored in the RAM 7 (S4). Next, r is reset (S5), after r is incremented (S6), reads the start address AD ₁ and material A from the RAM 6 (S7), the first number N ₁ from the position of the address AD ₁ of ROM4 Read (S
8). Subsequently, n is reset (S9), and after n is incremented (S10), the flight time M peculiar to the substance A is obtained.
₁₁ is read (S11), and the RAM 7
(S12). If there is a peak, YES is determined in step S13, and step S14 is determined.
In, n returns to S10 must match the N, searches similarly for another flight time M _12. On the other hand, n = N,
That is, if a predetermined number of flight times unique to the substance A are detected, a fire display is displayed on the display unit 8 (S15). And RA
The substance name is read from M6 (S16), and the substance name is displayed on the display section 8 (S17). Here, if r = R, the process returns to S1, and if r does not match R, the process returns to S6. On the other hand, in step S13, the flight time peculiar to the substance A is stored in the RAM.
If it is determined that the peak value does not fall within the range of 7, the process proceeds to step S18, and the same process is performed for the next substance B. Then, after searching all the specified substances, the peak value detected by the mass spectrometer 11 is read from the data analysis unit 10 again, and the flight time is searched in the same manner.

[0013]

The present invention will be described below with reference to examples. Example 1 A sample was used as a cellulose powder, and the product was smoked. Details of the test are shown below. First, on a ceramic heater, the cellulose powder was heated and calcined at 300 ° C., and introduced directly into the ionization means via a tube for collecting generated substances. The collected substances were converted to ⁶³ Ni using ionization means.
The sample was introduced into the above-mentioned TOF mass spectrometer using two electrodes as acceleration means and a collecting electrode as detection means. The electrodes are in positive mode or negative mode,
Each was tested. In addition, as a reference gas, T
NT and cocaine gases were mixed.

The TOF mass spectrometer used and its measurement conditions were as follows: TOF mass spectrometer, ion scan model 100 manufactured by Barrier, applied voltage, positive mode: 17
The measurement was performed at 80 V, 1950 V in negative mode, sample flow rate, 300 ml / min, applied pulse width, and 25 ms.

FIG. 6 and FIG. 7 show the results. In both figures, the vertical axis indicates the peak intensity and the horizontal axis indicates the flight time.
FIG. 6 shows the result when the electrode is in the positive mode. Flight time 8.60ms (No.16), 9.00m
s (No. 14), 10.10 ms (No. 15), 11.
50 ms (No. 17), 12.30 ms (No. 1)
8), 12.90 ms (No. 13), 16.15 ms
(No. 19) and 16.55 ms (No. 10) have peaks at respective positions. Among them, No. 10 and No. 1
5 is the reference cocaine and TNT, respectively. The peak of the baked substance of cellulose is No. 13,
14, 18, and 19. The other peaks, No.
No. 16 and No. 17 are the background by the used Teflon tube. FIG. 7 shows the result when the electrode is in the negative mode. 7.97 flight time
ms (No. 14), 9.27 ms (No. 12), 9.4
0 ms (No. 13), 10.69 ms (No. 9), 1
2.49 ms (No. 11), 13.86 ms (No. 1)
0), 14.22 ms (No. 1), 16.17 ms (N
A peak is observed at each position of o.8). Among them, No. 1
And No. 11 are cocaine and TNT, respectively, based on the respective standards.
Nos. 8 and 11. The other peaks, No.
9, 12, 13, and 14 are backgrounds of degradation products of cocaine and TNT. Tables 1 and 2 show the difference and the ratio between the flight time of the reference gas and the flight time at each peak obtained from the above results.

[0016]

[Table 1]

[0017]

[Table 2]

From the above results, in the case of this embodiment, Nos. 13, 14, 18, 19,
In the negative mode, the flight times of Nos. 8 and 11, preferably the correction values (difference or ratio) by the reference gas as shown in the above table are registered in the registration means, and the flight times of the air sampled from the monitored area are registered. (Or correction value) falls under any one or more of these,
The fire is determined by the determination means. The flight time of the air component changes under applied voltage and other conditions, and it is preferable to measure the flight time under various setting conditions. In the present embodiment, the case where cellulose is baked has been described, but if other substances such as various fibers and plastics are baked, the flight time is measured in the same manner and registered in the registration means. In the initial fire, when these substances are burned, it can be determined that the fire has occurred.

[0019]

According to the present invention, there is provided a fire detecting method and apparatus capable of accurately detecting a specific substance generated particularly at the time of an initial fire, whereby a fire is detected during the initial fire and damage is prevented. The least difficult to stop.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating an example of a TOF mass spectrometer that can be used in the present invention.

FIG. 2 is a block diagram of a fire detection device according to the present invention.

FIG. 3 is a diagram showing contents stored in a ROM 12 and a ROM 13;

FIG. 4 is a ROM 1 of a block diagram of a fire detection device of the present invention.
FIG. 2 is a diagram showing a flowchart of a program incorporated in the first embodiment.

FIG. 5 is a ROM1 of a block diagram of a fire detection device of the present invention.
FIG. 2 is a diagram showing a flowchart of a program incorporated in the first embodiment.

FIG. 6 is a diagram showing a mass spectrum obtained when a substance generated when the cellulose powder is smoked is subjected to a TOF mass spectrometer in a positive mode.

FIG. 7 is a diagram showing a mass spectrum obtained when a substance generated when the cellulose powder is calcined is applied to a TOF mass spectrometer in a negative mode.

[Explanation of symbols]

 Reference Signs List 17 sampling tube 18 ionization section 19 ion source 20 flight section 21 focus ring 22 collecting electrode 23 counter electrode

Claims (3)

(57) [Claims] 1. The method according to claim 1, wherein the air sampled from the monitored area is ionized, accelerated, and flown over a certain distance to measure the time of flight, and the measured time of flight measures at least one of the substances generated by the fire. A fire detection method, wherein a fire is determined when the flight time matches the flight time measured under the same conditions as described above. 2. The method according to claim 1, wherein one or more substances generated by the fire are ionized, accelerated, fly over a certain distance, measure the flight time, and register the obtained flight time in a registration means. Measuring the time of flight of the air sampled from the monitored area under the same conditions, comparing the time of flight with the time of flight of the substance registered in the registration means, and when at least one of the two times of flight coincides A fire detection method, characterized in that a fire is detected. 3. An ionizing means for ionizing air sampled from a monitoring area, an accelerating means for accelerating an air component ionized by the ionizing means, and measuring a flight time of the accelerated air component over a predetermined distance. Detecting means, a registration means capable of registering one or more flight times of a substance generated by a fire, and comparing the flight time detected by the detection means with the flight time registered in the registration means, Determining means for determining that a fire has occurred when at least one of the two flight times coincides with each other.