JPH058478B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention determines the type of fire based on temperature information, and when it is determined that the fire is ignitable, the detection sensitivity of the smoke detection unit is set high to quickly detect the fire. This invention relates to a smoke detection device capable of detecting fire.

(Prior Art) Conventionally, in scattered light smoke detectors that detect smoke caused by a fire, a light receiver receives scattered light emitted from a light emitter and caused by smoke, and a fire is determined based on the received light output. The results of various experiments have shown that the scattering coefficient varies depending on the type of smoke, such as the size of smoke particles, and in other words, the smoke detection sensitivity varies depending on the type of fire, such as ignitability or smoldering. Confirmed.

To explain specifically, Figure 4 shows experimental data showing the output of a scattered light type smoke detector against the light attenuation rate [%/m] when a pseudo fire condition is set, and graph A shows the output of a scattered light type smoke detector when a simulated fire condition is set. When set to smoky state,
Graph B shows the characteristics when wood is set to a smoldering state, and graph C shows the characteristics when volatile heptane (N-NEPTANE) is burned. Fourth
As is clear from the figure, in graph A, the output level E is reached when the light attenuation rate S1 [%/m] is set as the fire level, whereas in graph B, the light attenuation rate S2 is higher than the fire level S1. [%/m], furthermore, in graph C, the output level E is reached at the light attenuation rate S3 [%/m], which is a value significantly higher than the fire level S1, and the smoke detection sensitivity depends on the fire type. Changes are observed.

(Problem to be solved by the invention) In other words, when a flaming fire is set by burning volatile heptane, it is expected that the smoke particles generated will be smaller compared to a smoldering fire. , as shown in graph C, it affects the scattered light coefficient in the smoke detection part, and the smoke detection sensitivity is significantly reduced.
It is expected that there will be a time delay in fire detection and the damage caused by fire will increase.

(Means for Solving the Problems of the Invention) The present invention has been made in view of the above problems.
It is an object of the present invention to provide a smoke detection device that quickly and reliably detects smoke generated by a fire regardless of the type of fire such as a smoldering fire or a flaming fire.

In order to achieve this object, the present invention provides a smoke detection section comprising a smoke detection means for detecting smoke caused by the occurrence of a fire and a determination section for determining a fire based on a signal output from the smoke detection means, and a detection sensitivity of the smoke detection section. The smoke detection device is equipped with a sensitivity setting section that sets the temperature, and includes a temperature detection section that detects the temperature rise due to the occurrence of a fire in an analog manner, and a discrimination section that discriminates the type of fire according to the detection output from the temperature detection section. The sensitivity setting section is driven based on the discrimination output from the discrimination section to change the set sensitivity of the smoke detection section.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

First, the configuration will be explained. Reference numeral 1 is a scattered light type smoke detection means, which detects smoke caused by the occurrence of a fire. 2
is a light emitting circuit, which includes an oscillation circuit that oscillates in a predetermined synchronization therein, and outputs a light emission pulse based on the oscillation output from the oscillation circuit. 3 is a light emitting element;
It emits light intermittently based on the light emitting pulse from the light emitting circuit 2. A light receiving element 4 is installed at a position where the light emitted from the light emitting element 3 does not directly enter, and receives light scattered by the smoke of the light emitted from the light emitting element 3. Reference numeral 5 denotes a light receiving circuit, which includes a variable gain amplifier 5a and amplifies the light receiving output from the light receiving element 4 to a predetermined amplification degree. Reference numeral 6 denotes a judgment section which forms a smoke detection section together with the smoke detection means 1, and has a threshold level L2 set therein for determining a fire, and compares the received light output from the light receiving circuit 5 with the threshold level L2 to detect a fire. to decide. 7 is a display section equipped with display means such as LEDs and lamps, and indicates a fire based on the signal output from the judgment section 6. 8 detects the temperature rise due to the occurrence of a fire in an analog manner and performs a predetermined synchronization.
It is a temperature detection section that outputs temperature information every T ₀ ,
9 is a storage section that stores temperature information from the temperature detection section 8; 10 is an arithmetic processing section that calculates the amount of change based on the stored information from the storage section 9.

The arithmetic processing unit 10 will be explained in detail with reference to FIG. 2.The arithmetic processing unit 10 is set in advance to a calculation start level L1 lower than the level at which it can be determined that there is a fire, and the temperature detection Every time the temperature information d from the unit 8 is obtained, it is compared with the calculation start level L1, and when the value of the temperature information d exceeds the calculation start level L1, the calculation of the amount of change is started. That is, as shown in FIG. 2, the temperature information d9 with a value exceeding the calculation start level L1 is obtained from the storage unit 9 stored over a period of time t- ₃ , which is a predetermined period of time from the current time t0. Storage data d3, d4, d5,...d
9 is extracted, and the amount of change in each piece of the extracted storage data is calculated. Reference numeral 11 denotes a discrimination unit that discriminates the type of fire, which has a threshold value X ₀ set therein, and which uses the value of the amount of change from the arithmetic processing unit 10 and the threshold value X ₀ .
Based on the comparison result, the type of fire, that is, a flaming fire or a smoldering fire, is determined. Reference numeral 12 denotes a sensitivity setting section, which sets the detection sensitivity of the smoke detection section according to the discrimination output from the discrimination section 11. That is, the amplification degree of the amplifier 5a built in the light receiving circuit 5 is set to a predetermined amplification degree. Specifically, the amplification degree is set to G1 during normal times, and when the determination unit 11 determines that there is a fire on the ground, the sensitivity setting unit 1
Based on the signal output from 2, the amplification degree G2 is set to a higher value than the amplification degree G1.

Next, the operation of the present invention will be explained with reference to FIGS. 1 and 2.

First, to explain the operation when a smoldering fire occurs, when smoke generated from smoldering of wood etc. enters the smoke detection means 1, the light emitted from the light emitting element 3 is scattered by the smoke. The scattered light enters the light receiving element 4. The amplification degree of the amplifier 5a built in the light receiving circuit 5 is set in advance to a predetermined amplification degree G1, and the light receiving output from the light receiving element 4 is adjusted to a predetermined amplification degree G1.
The signal is amplified to 1 and output to the judgment section 6. In the judgment unit 6, the signal output from the light receiving circuit 5 and the threshold level L2 are determined.
If the output value from the light receiving circuit 5 exceeds the threshold value L2, it is determined that there is a fire, and the display unit 7 is driven to command a fire display.

Next, the operation when a flaming fire occurs will be explained. When gasoline or the like is combusted, a rapid temperature rise occurs, so the temperature detection section 8 also detects temperature changes in an analog manner. As shown in FIG. 2, the calculation processing unit 10 compares the temperature information d1, d2, d3, ... from the temperature detection unit 8 with the calculation start level L1 every time it is obtained, and at the current time _t0. When temperature information d9 from the temperature detection unit 8 that exceeds the calculation start level L1 is obtained,
The stored data d3, d4, d5, . . . d9 stored over a time period t- ₃ , which is a predetermined period of time back from the current time t0, is extracted as a signal output to the storage unit 9. The amount of change between each piece of extracted stored data is calculated. That is, x1=d 5-d3 x=2d 7-d5 x3=d 9-d7 (1) The amount of change x1, x2, x calculated in equation (1)
3 is given to the discrimination unit 11 and compared with the threshold value X ₀ . That is, x1>X ₀ x2<X ₀ x3>X ₀ (2) As shown in equation (2), the value of the amount of change x1 is the threshold
X ₀ or more, the value of the amount of change x2 is less than or equal to the threshold value X ₀ ,
Furthermore, if the value of the amount of change x3 is greater than or equal to the threshold value X ₀ , it is determined that it is noise because the amount of change that exceeds the threshold value X ₀ cannot be obtained continuously, and the signal output to the sensitivity setting unit 12 is prohibited. The setting amplifier G1 continues without changing the amplification degree of the amplifier 5a built in the light receiving circuit 5.

Next, as the fire spreads and as shown in FIG. The stored data from the storage unit 9 that has been stored over a period of time t4, which is a predetermined period of time back from the obtained time t7, is extracted, and the amount of change x4, x between each piece of stored data is extracted.
5, calculate x6. This amount of change x4, x5, x
6 is compared with the threshold value X ₀ in the discriminator 11 .

x4＞X ₀ x5＞X ₀ x6＞X ₀ (4) As shown in equation ( ₄ ), if the amount of change exceeding the threshold value and outputs a signal to the sensitivity setting section 12. The sensitivity setting section 12 sets the amplification degree of the amplifier 5a built in the light receiving circuit 5 to be high, that is, from G1 to G2, in accordance with the discrimination output from the discrimination section 11. On the other hand, the light-receiving element 4 connected to the light-receiving circuit 5 receives the scattered light from the smoke that has entered the smoke detection means 1, and the light-receiving output from the light-receiving element 4 is sent to the amplifier 5a built in the light-receiving circuit 5. The signal is further amplified to an amplification degree of G2 and provided to the determination section 6. If the value of the light receiving output from the light receiving circuit 5 exceeds the threshold value L2, the determining section 6 determines that there is a fire, and drives the display section 7 to instruct a fire display.

FIG. 3 is an explanatory diagram showing another example of determining the type of fire in FIG. 1. In this embodiment, a moving average process is applied to the temperature information from the temperature detection unit 8, and the type of fire, that is, a smoldering fire or a flaming fire, is determined based on the averaged processed data. It is characterized by what it did. As shown in FIG. 3A, when the temperature information d1, d2, d3, ... obtained from the temperature detection section 8 at every predetermined synchronization _T0 is given to the arithmetic processing section 10, the information as shown in equation (5) is obtained. Execute moving average processing.

D1 = (d1 + d2 + d3) / 3 D2 = (d2 + d3 + d4) / 3 D3 = (d3 + d4 + d5) / 3 ... ... (5) As shown in Fig. 3B, the processed data D1, D2, D3, ... are sequentially stored in the storage unit 9. Further, the calculation processing section 10 calculates the amount of change per unit time based on the processed data from the storage section 9. As shown in Figure 3B, time t-3 shows a rapid temperature change.
To explain specifically using the period from to t ₀ as an example, x1=Δ(D11−D10)/Δt x2=Δ(D12−D11)/Δt x3=Δ(D13−D12)/Δt (6) As shown in equation (6), the amount of change x1, x2, x3 per unit time between each processed data is given to the discrimination unit 11 and compared with the threshold value _X0 .

x1＞X ₀ x2＞X ₀ x3＜X ₀ (7) As shown in equation (7), the amount of change x1 and x2 are the thresholds
If X is greater than or equal to ₀ and the amount of change x3 is less than or equal to the threshold value X ₀ , then the amount of change that exceeds _the threshold value
That is, since there are two or more of the three smoke detectors, it is determined that there is a flaming fire, and a signal is output to the sensitivity setting section 12 to instruct it to change the set sensitivity of the smoke detection section to a higher value. The smoke detection section detects smoke that has entered the smoke detection means 1 with high sensitivity by switching the sensitivity based on a command from the sensitivity setting section 12.

In the above embodiment, the temperature information from the temperature detection section 8 is given to the arithmetic processing section 10 to calculate the amount of change.
Although the determination unit 11 is configured to determine the type of fire based on the amount of change from the arithmetic processing unit 10,
A threshold level R ₀ for determining a flaming fire is set in the determination unit 11, and the temperature information from the temperature detection unit 8 is directly provided to the determination unit 11, and the temperature information from the temperature detection unit 8 and the threshold level R ₀ are set. The configuration may be such that it is determined that the fire is flammable when the value of the temperature information from the temperature detection section 8 exceeds the threshold value _R0 .

Further, in the embodiment shown in FIG. 1, the light receiving circuit 5 is provided with a variable gain amplifier 5a, and the sensitivity setting section 1
2, the detection sensitivity of the smoke detection section is changed by changing the amplification degree of the amplifier 5a based on the command from the amplifier 5a. However, as another example, the value of the threshold level L2 set in the judgment section 6 may be changed. The threshold value L2 may be configured to be variable and may be configured to change the threshold value L2 based on a command from the sensitivity setting unit 12. That is, when the determining section 11 determines that there is a flaming fire, the threshold L2 set in the determining section 6 is set to a low value based on the command from the sensitivity setting section 12, thereby reducing the light receiving circuit 5. The detection sensitivity of the smoke detector can be changed without changing the amplification degree.

In addition, in the embodiment shown in FIG. 1, a so-called scattered light type smoke detection means that detects smoke based on scattered light caused by invading smoke is used as the smoke detection means 1. It may also be constructed using a so-called ionization type smoke detection means.

Furthermore, in the embodiment shown in FIG. 1, a composite smoke detection device including a smoke detection section and a temperature detection section was explained as an example, but a scattered light type smoke detector and an analog type temperature sensor were also described. are installed in the same monitoring area, and the detection information from the scattered light smoke detector and analog temperature sensor is received by a receiver installed in the center, and a judgment unit 6, The display unit 7, the storage unit 9, the arithmetic processing unit 10, the discrimination unit 11, and the sensitivity setting unit 12 may each be built in, and the receiver side may be configured to control the fire judgment and the sensitivity setting of the smoke detection unit. .

(Effects of the Invention) As described above, according to the present invention, the smoke detection unit includes a smoke detection unit that detects smoke caused by the occurrence of a fire, and a determination unit that determines a fire based on a signal output from the smoke detection unit. In a fire detection device equipped with a sensitivity setting section that sets the detection sensitivity of the smoke detection section, there is a temperature detection section that detects the temperature rise due to the occurrence of a fire in an analog manner, and a fire detection section that detects a fire according to the detection output from the temperature detection section. A determination unit is provided to determine the type of smoke, and the sensitivity setting unit is driven according to the determination output from this determination unit to change the sensitivity setting of the smoke detection unit. Smoke generated by a fire can be detected quickly and reliably, resulting in the effect that the reliability of the smoke detection device is greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is an explanatory diagram showing an example of fire type discrimination shown in FIG. 1, and FIG. 3 is an illustration showing an example of fire type discrimination shown in FIG. Fig. 4 is an explanatory diagram showing an example of the present invention, and shows experimental data when a fire condition is set in a simulated manner. 1: smoke detection section, 2: light emitting circuit, 3: light emitting element,
4: Light receiving element, 5: Light receiving circuit, 6: Judgment section, 7:
Display section, 8: Temperature detection section, 9: Storage section, 10: Arithmetic processing section, 11: Discrimination section, 12: Sensitivity setting section.

Claims (1)

[Scope of Claims] 1. A smoke detection section comprising a smoke detection means for detecting smoke due to the occurrence of a fire and a judgment section for determining a fire based on a signal output from the smoke detection means, and a detection sensitivity of the smoke detection section. In a fire detection device equipped with a sensitivity setting section for setting the temperature, the temperature detection section detects the temperature rise due to the occurrence of a fire in an analog manner, and the discrimination section determines the type of fire according to the detection output from the temperature detection section. A fire detection device characterized in that the sensitivity setting section is driven based on the discrimination output from the discrimination section to change the set sensitivity of the smoke detection section.