JPH0156439B2 - - Google Patents

Description

[Detailed description of the invention] The present invention predicts and calculates the degree of danger based on analog detection data such as temperature, gas concentration such as CO, smoke concentration, etc. to determine fire, and at the same time monitors the amount of change in the detection data. The present invention relates to a fire alarm device that detects a fire by detecting a fire.

Conventional fire alarm systems generally use a receiver to determine the on-off signal of a fire detector to notify a fire, and because they rely on the fire detector to determine whether there is a fire, they cannot detect causes other than fire. There was a problem that false alarms were likely to occur due to fire alarms, and if the detection sensitivity of the fire detector was lowered to prevent false alarms, a time delay would occur in fire detection.

For this reason, in recent years, progress has been made in the development of so-called analog fire alarm systems in which analog detection data from a fire detector is sent to a receiver, and the receiver makes a fire judgment.

The inventor has already filed a patent application for this type of device.
58-029976 (Japanese Unexamined Patent Publication No. 59-157789) has proposed a fire alarm device. In this proposal, due to the progression of physical changes in the surrounding environment due to the occurrence of fire,
The degree of danger is defined as the time it takes for the environment to reach a dangerous state for humans in the near future. In other words, future changes are predicted by mathematically known linear function approximation or quadratic function approximation based on past detection data obtained up to the present time, and this function approximation is used to predict future changes from the present time until a preset critical level is reached. The remaining time is defined as the risk level. Temperature is a dangerous environmental condition for humans.
Figure 1 shows fire data showing a linear and rapid rise in temperature caused by liquid organic solvents that are easily ignited. Figure 2 shows fire data showing a linear and rapid rise in temperature due to liquid organic solvents that are easily ignited. Detection data from the fire detector, Figure 3 shows that the temperature gradually rose after the fire broke out.
This is fire data that shows a rapid rise in temperature after a certain period of time has elapsed.For example, in the fire data shown in Figure 1, a dangerous temperature T _D that is dangerous to humans is set.
The time R1 required to reach the dangerous temperature T _D is defined as the degree of danger in the fire data shown in Figure 1.

Here, the dangerous temperature T _D that becomes dangerous to humans in the event of a fire is the fire detection temperature that is currently standardized as the operating point temperature of fixed temperature fire detectors.
60°C is used. In addition, when detecting smoke concentration, the dangerous smoke concentration is 5%/m for type 1, 10%/m for type 2, and 3.
Either 15%/m of seeds is used.

Therefore, the smaller the risk value, the higher the risk to humans. Therefore, this fire alarm system converts changes in physical phenomena in the surrounding environment into a multi-order approximation formula based on analog detection data from the fire detector, and calculates the remaining time until the dangerous temperature T _D is reached from the approximate formula. The degree of danger is determined, and a fire alarm is issued when the value of the degree of danger is shorter than a preset threshold, that is, a threshold time.

However, with the above device, all detection data, including normal base level detection data and non-fire detection data shown in Figure 2, are converted into an approximate formula to calculate the degree of danger. As the number of detectors increases, the calculation processing at the receiver increases, which may cause a time delay in fire detection when the temperature rises linearly and rapidly as shown in Figure 1. There was room left for.

The present invention has been made in view of the above-mentioned improvements, and it detects fires that cause a sudden linear temperature rise at an early stage, and cancels non-fire detection data and normal base level detection data. It is an object of the present invention to provide a fire alarm device that reduces the burden on a receiver that performs arithmetic processing on the degree of danger and reliably determines a fire through quick arithmetic processing.

In order to achieve this objective, the present invention calculates the difference between detection data such as temperature, gas concentration such as CO, smoke concentration, etc. detected by an analog detector as a difference value, and uses this difference value as a first threshold value and a second threshold value. compared to the threshold of
When the difference value exceeds the second threshold, a fire alarm is issued, and when the difference value is less than or equal to the first threshold, the detected data is canceled to reduce the computational processing burden on the receiver. exceeds the first threshold and the second
, the detection data from the detector is converted into an approximate formula, and the degree of danger is calculated from the approximate formula to make a fire judgment.

Embodiments according to the present invention will be described below based on the drawings.

FIG. 4 is a block diagram of a fire alarm system showing one embodiment of the present invention.

First, to explain the configuration, 1a, 1b, . and detection section 2
It has a built-in transmission circuit 3 that transmits the detected data. 4 is a receiver that incorporates a microcomputer and performs arithmetic processing based on the detection data from the detectors 1a, 1b...1n;
is connected to a plurality of analog detectors 1a, 1b, . . . 1n through a signal line 5. 6 is each detector 1a, 1b
...a receiving circuit that selects the detection data from 1n for each detector and sequentially receives it at fixed time intervals; 7 converts the analog value of the detection data received by the receiving circuit 6 into a digital value; A/
This is a D conversion circuit, and this A/D converted detection data is input to the storage circuit 8, and the detectors 1a to 1n
It is stored at the address specified for each time. Reference numeral 9 denotes an average value calculation circuit, which sequentially retrieves three detection data for each detector stored in the storage circuit 8 and calculates the average value of the three data values, and calculates sudden abnormal data due to noise etc. Prevent false alarms due to values. 10 is a difference value calculation circuit that calculates the amount of change for each predetermined period based on the average value calculated by the average value calculation circuit 9, using the difference between each average value as a difference value; The difference value indicating the difference value is output to the difference value determination circuit 11. The difference value determination circuit 11 has a second threshold α and a first threshold β lower than the second threshold α set in advance, and the difference value calculation circuit 10
It is compared with the difference value calculated in . To explain this comparison and judgment with reference to the drawings, Fig. 5 is a graph showing the difference value based on the fire data in Fig. 1, and Fig. 6 is a graph showing the difference value based on the detection data in Fig. 2. , and FIG. 7 is a graph showing difference values based on the fire data of FIG. 3. As shown in FIG. 5, when the difference value exceeds the second threshold value α, the alarm display circuit 14 is driven to display an alarm. As shown in FIG. 6, the difference value is the first threshold value β.
If it is below, it is determined that there is no fire, and the detected data as shown in FIG. 2 is deleted to reduce the computational processing burden on the receiver 4. Further, as shown in FIG. 7, when the difference value exceeds the first threshold value β and is less than the second threshold value α, the detected data stored in the storage circuit 8 is retrieved and output to the approximate expression calculation circuit 12. Then, approximate expression conversion is performed. Reference numeral 13 denotes a risk level determination circuit, which calculates the risk level R based on the approximate expression converted by the approximate expression calculation circuit 12, and compares it with a preset threshold R _s . If the value of the degree of danger R is smaller than the threshold R _s , that is, if the degree of danger is higher than the degree of danger set by the threshold R _s , the alarm display circuit 14 consisting of a buzzer, warning light, etc. is driven. Display a warning.

Next, the operation of the present invention will be explained with reference to the program flow diagram of FIG. Detector 1 in block a
The detection data from a, 1b, . The detection data for each detector is converted into a digital value by the A/D conversion circuit 7 and stored in the storage circuit 8. In block b, two pieces of detection data for each detector stored in the memory circuit 8 are sequentially taken out, and the average value of the three data values is calculated. For example, the detection data sampled and stored in the storage circuit 8 is D1, D2, D3...
Assuming that D _o , D _o+1 , D _o+2 . . . , the average values A1, A2, A3, A4, . . . A _o calculated in block b are expressed by the following equations.

A1=(D1+D2+D3)/3 A2=(D2+D3+D4)/3 A3=(D3+D4+D5)/3 A4=(D4+D5+D6)/3 〓 A _o = (D _o +D _o+1 +D _o+2 )/3 In block C, 2 based on the average values A1, A2, A3, A4, ... A _o calculated by the average value calculation circuit 9.
The amount of change is calculated every predetermined period by using the difference between the average values of the two as a difference value. For example, set the difference value to S1, S2, S3,
Assuming S4,...S _o , the calculation formula for the difference value is shown by the following formula.

S1=A4−A1 S2=A5−A2 S3=A6−A3 〓 S _o = A _o+3 −A _o Difference value S1 calculated by the difference value calculation circuit 10,
S2, S3, S4,...S _o are output to the difference value determination circuit 11 and compared with a preset threshold value. first,
In block d, a comparison is made with the first threshold value β. For example, if the detector 1a is installed in a cooking room or the like and the temperature gradually rises as shown in Figure 2, the difference value S at this time is smaller than the first threshold value β as shown in Figure 6. Then return to block a and select the next detector 1b.
Sample detection data from. Detector 1b
If the detection data from the sensor shows a linear and rapid temperature rise as shown in Figure 1,
As shown in FIG. 5, when the difference value S exceeds the first threshold value β, the process proceeds to block e, where it is compared with the second threshold value α. As shown in FIG. 5, when the difference value S exceeds the second threshold α, it is immediately determined that there is a fire, and the process proceeds to block h, where the alarm display circuit 14 is activated and an alarm is issued by sounding a buzzer or lighting a fire light. indicate.

Next, for example, if the temperature of the detector 1n suddenly rises after a certain period of time as shown in Figure 3, the difference value S at this time will be blocked by exceeding the first threshold value β as shown in Figure 7. The process proceeds from block e to block e, where it is compared with the second threshold value α. In FIG. 7, since the difference value S is less than or equal to the second threshold value α, the process proceeds to block f.

In this way, when the difference value S exceeds the first threshold value β and is less than or equal to the second threshold value α, the difference value determination circuit 1
Detector 1 stored in memory circuit 8 according to instructions from Detector 1
A plurality of past detection data from n to the present time are taken out and output to the approximate expression calculation circuit 12 to perform approximate expression conversion. The approximation expression conversion by the approximation expression calculation circuit 12 uses a plurality of detected data for linear function approximation or quadratic function approximation, for example, to convert the linear function expression (y=ax+c) or the quadratic expression (y=ax ² +
An approximate expression is obtained by performing mathematically known arithmetic processing to obtain the value of the coefficient in bx+c). In block f, the degree of risk R is calculated based on the approximate expression calculated by the approximate expression calculation circuit 12. That is, since changes in the detected data in the future can be predicted from the approximate expression, the remaining time from the present moment until reaching the predetermined dangerous temperature T _D is calculated as the risk level R.

The value of the risk level R determined as the remaining time from this current point until reaching the dangerous temperature T _D is compared with a threshold value R _S set in advance by the risk level determination circuit 13 . In other words, if the value of the risk level R in block g is greater than the threshold time R _S (if the remaining time until reaching the dangerous temperature T _D is longer than the threshold time)
Returning again to block a, the detection data from the next detector is sampled. Furthermore, if the value of the risk level R is less than the threshold value R _S (if the remaining time until reaching the dangerous temperature T _D is shorter than the threshold time), it is determined that there is a fire, and the process proceeds to block h, where the alarm display circuit 14 is driven. An alarm is displayed by sounding a buzzer and lighting a fire light. Here, the threshold value R _S is set to a time of about 2 to 3 minutes.

In the embodiment shown in FIG. 4, the A/D conversion circuit 7, storage circuit 8, average value calculation circuit 9, and difference value calculation circuit 10 shown in dotted lines are connected to the detectors 1a, 1b,
... ₁ If the configuration is built into the receiver 1
The burden of calculation processing can be further reduced.

As described above, according to the present invention, a difference value is calculated based on detection data sampled at predetermined intervals, and a fire alarm is issued by comparing it with a preset second threshold value. By making it
Fires that exhibit linear and rapid changes in physical phenomena can be detected at an early stage.

In addition, the detection data whose difference value is less than or equal to a preset first threshold value is deleted, and if the difference value exceeds the first threshold value and is less than or equal to the second threshold value, the detection data is deleted from the detector. The system converts the detected data into an approximate formula, calculates the degree of danger from the approximate formula, and issues a fire alarm by comparing it with a preset threshold, reducing the computational processing burden on the receiver. This has the effect of further improving the reliability of the fire alarm system by making it possible to reduce the amount of fire and process necessary detection data more quickly, and to make reliable fire judgments.

[Brief explanation of drawings]

Figure 1 shows fire data showing a linear and rapid rise in temperature, Figure 2 shows non-fire detection data showing a gradual increase in temperature in the cooking room, etc., and Figure 3 shows data after a certain period of time has passed since the fire broke out. Fire data showing a rapid temperature rise, Figure 4 is a block diagram showing an embodiment of the present invention, Figure 5 is a graph showing the difference between the fire data in Figure 1, and Figure 6 is Figure 2. 7 is a graph showing the difference value of the fire data in FIG. 3. FIG. 8 is a program flow diagram showing the operation of the fire alarm system in FIG. 4. . 1a, 1b,...1n: detector, 2: detection section,
3: Transmission circuit, 4: Receiver, 5: Signal line, 6: Receiving circuit, 7: A/D conversion circuit, 8: Memory circuit,
9: Average value calculation circuit, 10: Difference value calculation circuit, 1
1: Difference value judgment circuit, 12: Approximate expression calculation circuit, 1
3: Risk level judgment circuit, 14: Alarm display circuit.

Claims (1)

[Claims] 1. A detector that detects changes in physical phenomena in the surrounding environment due to the occurrence of a fire in an analog manner, and a receiver that samples detection data of the detector at predetermined intervals to determine whether there is a fire. A fire alarm device comprising: a difference value detection circuit that detects a difference value from the previous detection data every time the detection data is sampled; a second threshold that exceeds and is higher than the first threshold;
a difference value determination circuit that produces a determination output that instructs calculation of the degree of danger when the detected difference value exceeds the second threshold value, and outputs a fire alarm signal when the detected difference value exceeds the second threshold value; When the judgment output is obtained, a function approximation is performed based on the past detection data obtained up to the current point, and the remaining time from the current point until reaching a preset danger level is determined by the function approximation. What is claimed is: 1. A fire alarm system comprising: a risk level determination circuit that calculates the level of risk of a person and outputs a fire alarm signal when the level of risk falls below a predetermined time.