JP2690317B2 - Fire alarm - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fire alarm device that judges a fire when the degree of change of a fire phenomenon such as heat, smoke, or gas exceeds a predetermined level. is there.

[Background Art] For example, Japanese Utility Model Publication No. 59-28333 and Japanese Utility Model Publication No. 58-4
No. 4465 discloses that the degree of temperature change, that is, the temperature change rate is monitored, and the receiver is set when the temperature change rate reaches a certain rate of increase or continues for a certain time at a rate of increase above a certain value. 1 shows a so-called differential fire detector configured to output a fire signal in an electric circuit.

In such conventional differential fire detectors, a constant temperature rise rate for fire discrimination, or a constant time during which the constant temperature rise rate is to be continued, is always constant regardless of the ambient temperature around the heat detection unit. It is set constant. For this reason, when heating is performed in a state in which the room temperature has dropped to, for example, about 0 ° C. in winter, the temperature of the sensor set on the ceiling rapidly rises and exceeds the set temperature rise rate. There is a drawback that the set time elapses and a malfunction occurs. Conversely, in an environment such as a boiler room where there is always a temperature of 40 to 50 ° C., even if a fire occurs, it is difficult to obtain a predetermined rise rate and a lapse of a certain period of time. There are drawbacks. As described above, the differential heat sensor cannot be used depending on the environmental temperature condition, and the room temperature heat sensor must be installed instead.

[Problems to be Solved by the Invention] As described above, in the conventional differential fire alarm device such as the differential heat sensor, a malfunction or a delay or a failure is likely to occur depending on environmental conditions. was there.

[Means for Solving Problems] The present invention has been made to solve the above problems, and sets a reference level by detection data of heat, smoke, gas, or the like for a predetermined time (a predetermined number of sampling times). Seeking,
The fire is discriminated by whether or not the difference between the reference level and the detection level such as the current temperature has reached a set value.

Furthermore, the set value (operation width) for fire determination is made to differ depending on environmental conditions such as environmental temperature.

Specifically, according to the present invention, means for obtaining a difference between the reference level and the latest detection level, means for determining whether or not the difference has reached a set value, and continuous detection levels for a predetermined time And second means for averaging the continuously read detection levels for a predetermined time in order to obtain the reference level. A fire alarm device is provided.

Further, according to the present invention, as the reference level obtained by the second means becomes larger (from the distant side to the approaching side with respect to the level indicating the fire abnormality), the set value becomes large to small. And a third means for changing the setting.

[Operation] The second means constantly averages detection levels for a predetermined time by using a weighted average or a moving average, and uses the average value as a reference level. The reference level obtained in this way follows the environmental changes with a delay, and is judged to be a fire when the difference between the latest detection level and the reference level reaches the set value.

Further, the third means sets, based on the reference level obtained by the second means, such that the level representing the fire abnormality increases from the larger side to the smaller side from the distant side to the approaching side. I am trying to change the value,
Thus, for example, in the case of a thermal type sensor, the possibility of malfunction is reduced by increasing the set value when the temperature rapidly rises due to heating from a low temperature state, and the reference level is high, that is, the ambient temperature is high. In this case, it is possible to detect a fire early by setting a small set value.

[Example] An example of the present invention will be described below with reference to the drawings, taking an example of a thermal type that detects a temperature as a physical quantity.

FIG. 1 is a block circuit diagram showing an example of a fire alarm device to which an embodiment of the present invention is applied. In the figure, RE is a receiver, DE _{11 to} DE ₁ n ... DEn _{1 to} DEnn are , A fire detector connected to the receiver RE by a pair of power supply and signal lines L _{1 to} Ln, respectively. Note that only the inside of the fire detector DE ₁₁ is shown in detail, but the same applies to other fire detectors.

In the fire detector DE ₁₁ , the MPU is a microprocessor, and the ROM 1 is a program storage area in a main memory associated with the microprocessor MPU, and fixedly stores a program described later with reference to the flowchart of FIG.

The ROM 2 fixedly stores a table of the operation width ΔV with respect to the average value Vav. RAM1 is a sensor output level storage area in the main memory for storing the average value vs. motion width table storage area in the main memory, RAM1 for rewriting and storing N detection output levels, that is, sensor output levels at any time. The work area in the main memory, FS is a fire phenomenon detection unit that detects a physical quantity related to a fire, and is a thermal detection unit in this embodiment.

TH is a thermistor as an example of a heat-sensitive element, AD is an analog-digital converter, TX is a fire signal transmission unit (in the polling system, it is a transmission / reception unit), IF1 and IF2 are interfaces, is there.

The operation of FIG. 1 will be described with reference to the flowchart of FIG.

First, the detection output level converted from the fire phenomenon detection unit FS to a digital signal by the analog / digital converter AD, that is, the sensor output level SLV is the interface IF1.
Is read into the work area RAM2 every few seconds, for example, every two seconds (step 201), and the sensor output level read into the RAM2 is then written into the sensor output level storage area RAM1 as the current level. . At that time, the oldest data is discarded (step 202).

The sensor output level storage area RAM1 is shown in FIG. 3, and the storage locations of N data (that is, sensor output levels) are shown. The latest data, that is, the sensor output level, is stored in the uppermost position of the storage area, the data stored up to that point are sequentially shifted downward by one, and the last data, that is, the lowest data. The data will be discarded. In this way, the latest N data are always stored.

When the latest sensor output level SLV is stored in the uppermost location of the sensor output level storage area RAM1, next N is stored in the sensor output level storage area RAM1.
The sensor output levels are summed (step 203), and the moving average sensor output level Vav is calculated by dividing the sum by N (step 204). The decimal point generated by the division is rounded down here.

Next, the operation level width ΔV corresponding to the average sensor output level Vav is read from the average value vs. operation width table storage area ROM2 and stored as V ₂ in the work area RAM2 (step 205).

An area ROM2 for storing the average value vs. motion width table is shown in FIG. One storage location is provided corresponding to each average value Vav represented by an integer, and each storage location is
The operation level width ΔV corresponding to each average value is stored. The relationship between the average value Vav and the operation level width ΔV is as shown in the graph of FIG.
The operation level width ΔV decreases as the temperature rises, which is suitable for fire monitoring. In the case of smoke or gas, the horizontal axis is the average smoke concentration (dust amount) or average gas concentration of the environment.

Therefore, the amount of environmental conditions such as temperature, dust, and gas is large,
When the average value Vav (that is, the reference level) is large, the operation level width ΔV (that is, the set value) is set to a small value in order to avoid the possibility of false alarm. When the amount of environmental conditions is small and the average value Vav is small, the operation level width ΔV is set to a large value to avoid the possibility of false alarm.

In step 205, the average value vs. operation level width table storage area ROM2 is read and the operation level width ΔV is stored in the work area RAM2 as V ₂ , and the average is calculated from the current sensor output level SLV read in step 201. It is determined whether the value obtained by subtracting the value Vav is larger than the operation level width ΔV (step 206). If the difference is smaller than the operation level width ΔV (N in step 206), the next sensor output level is read and the operation from step 201 is similarly executed. If the difference is not less than the operation level width ΔV (Y in step 206), the fire sending unit TX is operated via the interface IF2 and the fire signal is sent to the receiver RE (step 207). At this time the fire signal transmitter TX
May send its own address together with the fire signal.

A fire signal from the fire detector is received by the receiver RE, the receiver RE is judged whether it has received the fire signal from any of the line L ₁ Ln, and displays the generated fire alarm district fire . If the fire detector also sends out its own address, the location of the fire or the fire detector that has operated is also determined from the received address signal and displayed together.

In the above embodiment, the case where the present invention is applied to a fire alarm device in which a fire detector performs a fire determination and transmits a fire signal and / or an address signal to a receiver has been described. Is an analog fire alarm that sends a physical quantity signal of the detected fire phenomenon, and performs a fire discrimination based on the physical quantity signal sent from the analog fire sensor with a receiver or a relay device, so-called analog fire alarm The present invention can be applied to an apparatus.

As described above, when the present invention is applied to a fire alarm device that performs fire discrimination by a receiver or a relay, the fire detectors DE _{11 to} DEnn in FIG. 1 are analog fire detectors (fire sensors), For each fire sensor, ROM2 for storing average value vs. operating width table and RAM1 for storing sensor output level
Is omitted, and the transmission unit TX serves as a transmission / reception unit that transmits and receives signals to and from the receiver RE. Then, the program storage ROM 1 stores a program for sending data of the detection output level of the fire phenomenon detection unit FS to the receiver RE via the transmission / reception unit TX when a call is received by polling from the receiver RE. You.

On the other hand, the receiver RE or the repeater has a microprocessor MPU in the fire detector DE ₁₁ shown in FIG. 1, a ROM 1 for storing a program, a ROM 2 for storing an average value vs. operating width table, and a RAM 1 for storing a sensor output level. , Work RAM2 and transceiver
TX etc. are provided. Then, the ROM 1 for program storage sequentially polls a plurality of connected fire sensors to read the respective sensor output levels SLV, and each time the sensor output level SLV is read, the fire sensors are read in the same flow chart as in FIG. A program is stored in which the fire is discriminated and the result is displayed on the display unit or the like. Further, the sensor output level storage RAM 1 is provided with a storage area capable of storing N sensor output levels for each of a plurality of connected fire sensors.

Further, in the above embodiment, only the operation level width ΔV is gradually decreased as the average value Vav increases, but the average value Vav is set to a predetermined temperature, for example, 70 ° C.
If the operation level width ΔV is set to an appropriate value of about 0 ° C. to 10 ° C. at the time of reaching, it will be more effective in preventing delay or loss of information.

As described above, according to the present invention, the reference level is obtained by averaging the detection levels of heat, smoke, gas, or the like for a predetermined time that are continuously read, and the reference thus obtained is obtained. When the difference between the level and the current detection level exceeds the set value, it is judged as a fire. Further, the set value is changed according to the reference level, and the change mode is such that the set value is changed from the large value to the small value as the reference level increases, so that the detection level from the fire phenomenon detection unit is far from the fire occurrence. If you are showing an environmental condition,
The set value is set to be large, and the set value is set to be small when the environmental condition is close to the occurrence of a fire. Therefore, the possibility of false alarm or false alarm is reduced as much as possible.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing a fire alarm device according to an embodiment of the present invention, FIG. 2 is a flow chart for explaining the operation of FIG. 1, and FIG. 3 is a sensor output level of FIG. FIG. 4 is a diagram showing details of a storage area RAM1, FIG. 4 is a diagram showing details of an average value vs. operating width table storage area of FIG.
FIG. 5 is a graph showing the relationship between the average value and the operation width stored in the average value vs. operation width table storage area. In the figure, RE is a receiver, DE _{11 to} DEnn are fire detectors, MPU is a microprocessor, FS is a fire phenomenon detector, ROM1 is a program storage area, ROM2 is an average value vs. operating width table storage area, and RAM1 is The sensor output level storage area, RAM2 is a work area, and TX is a fire signal transmission unit.

Claims (2)

(57) [Claims] 1. A means for obtaining a difference between a reference level and the latest detection level, a means for determining whether or not the difference has reached a set value, and a detection level for a predetermined time which is continuously read and stored. First means, a second means for averaging the continuously read detection levels for a predetermined period of time to obtain the reference level, and as the reference level obtained by the second means increases. And a third means for changing the setting so that the set value is changed from a large value to a small value, and a fire alarm device. 2. The fire alarm device according to claim 1, wherein the third means changes the set value when the reference level reaches a predetermined value.