JPH0731754B2 - Fire alarm - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fire alarm device adapted to detect a fire by detecting temperature, smoke density, etc. due to the fire with an analog sensor.

[0002]

2. Description of the Related Art In recent years, in order to solve the problems of false alarms and fire detection delays in so-called on / off type fire alarm devices, which used a fire detector with a threshold value to make a fire decision, the temperature, smoke density, The practical application of a so-called analog fire alarm device in which a CO gas concentration or the like is detected by an analog sensor and sent to a receiver and a fire is judged based on the detection data on the receiver side is being promoted.

By the way, the detection data obtained from the analog sensor installed in the alarm area of such an analog fire alarm device is the shape of a room in the alarm area even if the fire conditions are the same, that is, the floor area and the ceiling height. It is expected that the diffusion state of smoke and CO gas from the fire source position with respect to the sensor installation position and the temperature rise at the sensor installation position will differ depending on the temperature.

Therefore, the inventors of the present invention have proposed a device capable of processing a fire judgment without being affected by the height of installation even if the height of the ceiling where the sensor is installed is different (Japanese Patent Application No. Sho. 59-14026).

[0005]

However, not only the height of the sensor installation but also the floor area of the sensor installation area is a major factor in the shape of the sensor installation area. Depending on the size of the area, the change in the detection data obtained from the sensor over time,
If the fire is judged by uniformly processing the detection data that changes with time depending on the floor area, there is a possibility that both early detection of the fire and prevention of false alarms cannot be achieved.

[0006] For example, in a small room, a high smoke density is detected even by cigarette smoke and the like, so that false alarms are more likely to occur than in a large room. Since it takes a long time to spread the data, there is a large time delay in the detection data, and there is a problem that it takes more time to judge a fire than in a small room. The present invention has been made in view of such conventional problems, and even if the floor area of the warning area controlled by the analog sensor that detects the change in the physical phenomenon due to the fire is different, the influence of the floor area is affected. An object of the present invention is to provide a highly reliable fire alarm device capable of performing a fire determination process without receiving a fire.

[0007]

[Means for Solving the Problems] In order to achieve this object, the inventors of the present application continued data analysis research of a fire experiment conducted by changing the room area, and found that the floor area and the detection It was found that there was a predetermined correlation with the data, and based on this correlation, the fire judgment threshold was corrected by a predetermined correction coefficient determined by the floor area, and the fire judgment of the sensor data was made. is there.

That is, the fire alarm device according to the present invention includes analog sensors 1a to 1a which detect analog changes in physical phenomena in the surrounding environment due to the occurrence of a fire and output analog detection signals.
1n, the warning area setting means 5 for setting the floor area of the warning area under the control of the analog sensors 1a to 1n, and the floor area changes according to the warning floor area set by the warning area setting means (area setting part) 5. Even if a threshold value for performing a fire determination is corrected and calculated so that the time until a fire determination is the same, a threshold value correction unit (threshold value correction circuit) 20 and a correction threshold value calculated and set by the threshold value correction unit 20 are set. A fire judging means (fire judging circuit) 4 for making a fire judgment of a detection signal by using it, and an alarm display means (alarm display section) 8 for making an alarm display by the fire judgment output of the fire judging means 4 are provided. To do.

[0009]

According to the correction of the threshold value for making a fire judgment based on the floor area according to the present invention, the floor area of the warning area controlled by the sensor is different, and even if the fire is of the same scale, the floor area is different. Even if the temporal changes in the detected data are different, the threshold can be corrected to make a fire judgment approximately the same time after the fire started, and even if you smoke a cigarette in a small room, a false fire judgment will be made. It is possible to reliably prevent such a situation, and even in a large room, it is possible to make an early fire judgment as in a small room without causing a time delay.

[0010]

1 is a block diagram showing an embodiment of the present invention. First, the configuration will be described. 1a, 1b, ... 1
n is an analog sensor, for example, a smoke concentration sensor, a temperature sensor, a CO gas sensor, or the like is used, and is installed on the ceiling surface of a room that is a warning area and outputs an analog signal according to the smoke concentration, temperature, and CO gas concentration. To do.

Reference numeral 2 denotes a sampling circuit, which sequentially samples the analog detection signals output from the plurality of analog sensors 1a to 1n at regular time intervals and outputs them. 3 is A
The D / D converter converts analog detection signals sequentially obtained from the sampling circuit 2 into digital signals (hereinafter referred to as "sensor data"). 4 is a fire judgment circuit,
Using the correction threshold value set by the threshold value correction circuit 20, A /
Fire judgment of the sensor data from the D converter 3 is performed. The threshold value for the fire determination circuit 4 is given from the threshold value correction circuit 20, and the threshold value correction circuit 20 serves as a reference set in advance based on the warning floor area S of the sensor installation area set by the area setting unit 5. The threshold value is corrected and given to the fire determination circuit 4.

For the fire judgment in the fire judgment circuit 4, for example, a function approximation based on a plurality of temporally continuous sensor data, for example, a quadratic function approximation is used to predict the time until reaching a predetermined risk level. A predictive calculation process for determining a fire when the predicted time is equal to or shorter than a predetermined time set as a correction threshold by the threshold correction circuit 20.
Alternatively, the sensor data is compared with a correction threshold value obtained by correcting a predetermined threshold value by the threshold value setting circuit 20, and a fire determination process of determining a fire when the correction threshold value is exceeded is performed.

An alarm display unit 8 receives a fire judgment output from the fire judgment circuit 7 and displays a fire alarm by a warning bell or a fire indicator lamp. Next, the principle of threshold value correction based on the warning floor area performed by the threshold value correction circuit 20 of FIG. 1 will be described. FIG. 2 shows the time variation of smoke density when the same fire condition, for example, smoldering cotton, is used in rooms with different floor areas.

In FIG. 2, the time change of increasing smoke density is obtained as a substantially linear change, and the straight line 10 is the time change in a narrow room, and the straight lines 11 and 12 are widened in this order. It shows the change over time. As is clear from the experimental data in FIG. 2, the smaller the floor area, the greater the temporal change in smoke concentration, and the larger the room, the less temporal change in smoke concentration. As a result, the warning area under the control of the sensor It is necessary to correct the fire judgment threshold according to the floor area of the fire.

FIG. 3 is a characteristic graph showing the relative value of the sensor output obtained by conducting a fire experiment by changing the room area in five steps. That is, the sensor is installed at a constant height of 2.5 m, and the floor area is based on a span of 4.3 m × 6.7 m blocked by a beam in the building. The floor area is varied in 5 steps up to 58 m × 3.48 m, and the sensor output when the floor area is different is obtained to obtain the characteristic graph of FIG.

The characteristic graph of FIG. 3 shows the relative values of the sensor output with respect to the room area for each of smoke concentration, temperature and CO gas concentration. Here, the temperature, smoke concentration, and CO gas concentration tend to converge to a constant value as the room area increases, and the sensor output that converges is set as a reference value 1 when the room is assumed to be infinitely wide. Seeking relative value.

The characteristic curves of temperature, smoke concentration and CO gas concentration shown in FIG. 3 are approximate curves obtained by the method of least squares based on the sensor data of each measurement point, and each characteristic curve is expressed by the following equation. be able to. RT = 1.0exp (−0.08S) +1 (1) RS = 4.2exp (−0.15S) +1 (2) RG = 9.6exp (−0.11S) +1 (3) However, S floor area [m ² ] Therefore, in order to apply the same fire determination process even if the room area is different, the relative values RT, RS, and RG obtained by the equations (1) to (3) are It suffices to multiply by a reference threshold value as a correction coefficient.

Therefore, a reference threshold value to be corrected is set in the threshold value correction circuit 20, and this reference threshold value is obtained as a convergence value when the room area is made infinite in the characteristic graph of FIG. An appropriate threshold value to be set, for example, smoke density, is set to 10% / m. When the correction calculation circuit 20 receives the setting of the warning floor area S under the control of the sensor from the area setting unit 5 with respect to this reference threshold value, the correction calculation circuit 20 receives the first (1)
The relative values RT, RS, and RG are calculated based on the equations (3) to (correction threshold) = (reference threshold) × (relative value), and the correction threshold is obtained and set in the fire determination circuit 4.

Incidentally, the relative values RT, RS, RG with respect to the floor area S are previously obtained as the correction coefficients from the equations (1) to (3) without performing the operations of the equations (1) to (3), By storing these correction coefficients in the memory with the floor area S as an address, the floor area S may be given to uniquely obtain the correction coefficients. Next, the operation of the embodiment shown in FIG. 1 will be described.

First, the area setting unit 5 causes the analog sensor 1 to
Warning areas S1, S2, ...
..Set Sn. This setting of the guard area sets the floor area of the room when only one analog sensor is installed in one room, and in the case of a room with a beam on the ceiling, it is surrounded by a beam. Since one analog sensor is installed in the enclosed ceiling part, the floor area corresponding to the part surrounded by this beam is set.

When the warning floor area is set by the area setting unit 5, the threshold correction circuit 20 sets a correction threshold value corresponding to each of the warning areas S1 to Sn. That is, the relative values RT and R are set by including the guard areas set in the equations (1) to (3) according to the types of sensors such as temperature, smoke concentration, and CO gas concentration.
S and RG are obtained, and the relative threshold value is multiplied by this relative value to set each of the correction threshold values.

When the correction threshold value setting process for each sensor is completed in this way, the sampling circuit 2 causes the analog sensor 1
The analog detection data obtained from a to 1n are sequentially sampled at regular intervals, converted into digital data by the A / D converter 3, and supplied to the fire determination circuit 4. The fire judgment circuit 4 judges a fire by comparing the predicted time until reaching the danger level obtained by the function approximation method from the sensor data with the corrected threshold time, or by comparing the sensor data with the correction threshold, When a fire is judged, a fire alarm is issued from the alarm display section 8.

As another embodiment of the present invention, in addition to the above-described correction of the reference threshold value according to the floor area, Japanese Patent Application No. 59-140 is also available.
In No. 26, by multiplying the reference threshold value by the correction coefficient of the sensor installation height which has been already proposed by the inventors of the present application, it is possible to make a fire judgment that is not affected by the floor area and the sensor installation height. As the correction coefficient for eliminating the influence of the sensor installation height, for example, the correction coefficient y according to the characteristics of FIG. 4 is used for smoke density, and the temperature of FIG.
The correction coefficient y according to the characteristic curve is used.

That is, the threshold value is corrected by multiplying the reference threshold value according to the type of sensor by the correction coefficient based on the floor area of the present invention and the correction coefficient y according to the sensor installation height shown in FIGS. By making a fire judgment based on the corrected correction threshold, a fire judgment that is not affected by the floor area of the warning floor and the height of sensor installation, in other words, the shape of the room where the sensor is installed, is made. You can

In the above embodiment, the case where the fire is judged by correcting the threshold value in the receiver is taken as an example. However, the present invention is not limited to this, and a conventional on / off type fire is used. Regarding the threshold value setting in the sensor, the threshold value corrected according to the floor area may be set by the sensor itself as in the embodiment of FIG.

[0026]

As described above, according to the present invention, the threshold value for fire judgment is corrected by the predetermined correction coefficient determined by the floor area, and the fire judgment is made by comparing with the sensor data. Regardless of the floor area of the place, it is possible to make a fire judgment approximately the same elapsed time from the fire occurrence, even if it is a large room, there is no time delay in the fire judgment, and a fire occurs almost like a narrow room Therefore, it is possible to make a fire judgment in a short time, and it is possible to reliably prevent an erroneous fire judgment even if a cigarette is smoked in a small room or the like.

Further, even in a large room, there is no difference in the judgment time until a fire judgment is made, compared with a small room, so just by installing one sensor in a large room, a fire judgment equivalent to a narrow room can be made. Therefore, it is possible to reduce the number of sensors installed in the warning area.

[Brief description of drawings]

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

[Fig. 2] A graph showing the time variation of smoke density when a fire experiment is performed by changing the room area.

FIG. 3 is a characteristic graph diagram showing relative values of sensor outputs with respect to room area.

FIG. 4 is a graph showing a relationship between a sensor installation height and a correction coefficient in a smoke sensor.

FIG. 5 is a graph showing a relationship between a sensor installation height and a correction coefficient in a temperature sensor.

[Explanation of symbols]

 1a-1n: Analog sensor 2: Sampling circuit 3: A / D converter 4: Fire determination circuit 5: Area setting part 8: Warning display part 20: Threshold correction circuit

Claims (1)

[Claims] 1. An analog sensor for analogly detecting a change in a physical phenomenon of the surrounding environment due to a fire and outputting an analog detection signal, and a security area for setting a floor area of a security area controlled by the analog sensor. According to the setting means and the warning floor area set by the warning area setting means, the threshold value for making the fire judgment is corrected and set so that the time until the fire judgment becomes the same even if the floor area changes. Threshold correction means, fire judgment means for making a fire judgment of the fire detection signal using the correction threshold calculated and set by the threshold correction means, and alarm display means for making an alarm display by the fire judgment output of the fire judgment means. A fire alarm device characterized by being provided with.