JP5133031B2 - Fire alarm - Google Patents

Description

  The present invention provides a plurality of fire phenomenon detection units that detect a phenomenon caused by a fire such as smoke, CO, and heat, and determines the occurrence of a fire based on the detection results detected by these fire phenomenon detection units. The present invention relates to a combined fire alarm device.

  The most common cause of death from fire is fire caused by mismanagement of tobacco. In this case, it is often a smoldering fire accompanied by generation of a large amount of CO gas.

  As one of the conventional combined fire alarms, the sensing state that distinguishes the status of fire, non-fire, fire caution etc. from the combination of each output of the smoke detector, CO detector, smoke detector and CO detector A device including a determination unit is known (for example, see Patent Document 1). In this combined fire alarm, when the sensing state determination unit determines the fire state, the occurrence of the fire is notified. When the fire caution state is determined, the determination values assigned to the fire caution state are integrated, and if the integrated value exceeds a predetermined threshold value, the possibility of fire is notified. However, since the state determination conditions in the sensing state determination unit remain fixed, it is difficult to accurately distinguish between smoking and fire in which the degree of smoke generation and the degree of CO generation are slightly different.

  As one of the conventional composite fire alarms, the elapsed time until the output value of the smoke detector reaches the second level from the first level is measured, and according to this elapsed time, the alarm notification grace time is It is known that the accumulation time and the output values of the smoke detection unit and the CO detection unit are changed, and fire determination is performed based on the changed accumulation time and output value (for example, see Patent Document 2). In this combined fire alarm, the judgment conditions for fire judgment are changed each time. However, since the judgment condition is changed only by the time-dependent change of the measured value of a single fire phenomenon such as the output value of the smoke detector, the combined generation degree of both smoke and CO is not taken into account. It is difficult to accurately distinguish between smoking and fire.

JP 2006-146843 A (paragraph number 0006-0010, FIG. 2) JP 2006-146738 (paragraph number 0006-0016, FIG. 2)

  In view of the above situation, the object of the present invention is to adjust the judgment condition of fire occurrence based on the combined occurrence degree of the phenomenon caused by fire such as smoke and CO, and to deal with non-fire such as smoking and mismanagement of cigarette It is to provide a fire alarm that can identify fires caused by fire as accurately and as early as possible.

  In order to solve the above-described problems, a fire alarm according to the present invention includes a first fire phenomenon detection unit that detects a first phenomenon caused by a fire, and a second fire phenomenon that detects a second phenomenon different from the first phenomenon. Based on a fire alarm determination condition, a detection unit, a first phenomenon detection value corresponding to a detection signal of the first fire phenomenon detection unit, and a second phenomenon detection value corresponding to a detection signal of the second fire phenomenon detection unit An evaluation unit that evaluates and outputs a fire alarm notification command; a first time point at which the detected value of the first phenomenon exceeds a warning threshold value of the first phenomenon; and a detected value of the second phenomenon alerts the second phenomenon. A fire alarm that adjusts the fire alarm determination condition based on a reference time that is an elapsed time between a second time point that exceeds a threshold value and a reference detection value that is a detection value of a first phenomenon after the second time point A determination condition adjustment unit. Here, the detection value of the first phenomenon used as the reference detection value may be one that is detected after the second time point. Preferably, the detection value is detected each time after the second time point. In other words, the current detected value may be adopted. However, the detection value detected at the second time point can also be adopted as a fixed value.

  According to this configuration, the detection value for the second phenomenon caused by the fire exceeds the warning threshold value from the first time point when the detection value for the first phenomenon caused by the fire exceeds the warning threshold value. The fire alarm determination condition is adjusted from a reference time that is an elapsed time up to a time point and a detection value for the first phenomenon as the reference detection value. In other words, the criteria for determining whether or not to issue a fire alarm is adjusted based on the combined degree of occurrence of two phenomena caused by fire, so that non-fire and fire can be identified as accurately and early as possible. Is possible. The phenomenon caused by the fire includes a change in CO concentration, a change in smoke concentration, a temperature change, and the like, and it is preferable to select an optimum one from them according to the priority of the fire type to detect.

  In a special fire, the detection value for the second phenomenon may exceed the warning threshold value while the detection value for the first phenomenon does not exceed the warning threshold value. In order to deal with such a case, in the present invention, a predetermined shortest time, preferably zero, is set as the reference time.

  In particular, in order to distinguish between non-fires such as smoking and burning fires caused by tobacco mismanagement, changes in smoke concentration and CO concentration play an important role as a phenomenon caused by the fire. Empirically and experimentally revealed. Accordingly, in one preferred embodiment of the present invention, the first fire phenomenon detection unit is configured as a CO detection unit that detects CO, and the second fire phenomenon detection unit is configured as a smoke detection unit that detects smoke. Has been.

In the present invention, one of the fire alarm determination conditions is an alarm threshold value for the second phenomenon, and a fire alarm notification command is output when a detected value of the second phenomenon exceeds the alarm threshold value. Is done. In this configuration, the detection value of the second phenomenon is compared with the alarm threshold value in order to determine whether or not to output the fire alarm notification command. Since this alarm threshold value is adjusted based on the reference time and the reference detection value in advance, it is possible to make a fire determination in consideration of the combined degree of occurrence of two phenomena caused by a fire. The relationship between any combination of the reference time and the reference detection value and the alarm threshold for the second phenomenon can be obtained by an experimental and statistical method. At this time, it is convenient to create a function composed of two parameters of a reference time and a reference detection value for deriving the alarm threshold value. If this function is registered, an alarm threshold value for the second phenomenon can be obtained by calculation from the obtained reference time and reference detection value. More preferably, if the relationship between the reference time, the reference detection value, and the alarm threshold value for the second phenomenon is registered as a table, the alarm threshold value to be obtained can be derived without the need for calculation. be able to.

  As one of the further fire alarm determination conditions, an accumulation time as a countdown time until the fire alarm notification command is output from the second time point as a starting point, together with an alarm threshold for the second phenomenon, Or it can employ | adopt independently. That is, one of the fire alarm determination conditions is an accumulation time as a countdown time from the second time point to the output of the fire alarm notification command, and preferably the elapsed time from the second time point The condition where the detected value exceeding the warning threshold value is detected and the storage time is exceeded is regarded as a requirement for outputting the fire alarm notification command. Even in this case, it is convenient to create a function including two parameters of a reference time and a reference detection value for deriving the accumulation time. Furthermore, it is convenient to register the function itself or to register the reference time and the relationship between the reference detection value and the reference time as the function value in a table form.

  Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In this embodiment, the CO concentration is adopted as the first phenomenon caused by the fire, the smoke concentration is adopted as the second phenomenon, the smoke concentration is determined over the accumulation time as the final judgment condition for judging the fire occurrence and notifying the fire alarm. It is adopted that the alarm threshold is exceeded. As shown in FIG. 1, such a fire alarm 1 includes a CO detection unit 10 (first fire phenomenon detection unit) for detecting CO and a smoke detection unit 20 (second fire phenomenon detection unit) for detecting smoke. A controller 30 that evaluates the CO concentration as the CO detection value corresponding to the detection signal of the CO detection unit 10 and the smoke concentration as the smoke detection value corresponding to the detection signal of the smoke detection unit 20 to determine the occurrence of a fire; And an alarm driving unit 40 for driving alarm means 50 such as a buzzer, a lamp, and an audio output device based on a fire alarm notification command output from the controller 30.

  The CO detection unit 10 is configured by a hot-wire semiconductor sensor. For example, a hot-wire semiconductor sensor covers and covers a noble metal wire such as platinum, palladium, or platinum-palladium alloy with a metal oxide semiconductor mainly composed of a metal oxide such as indium oxide, tungsten oxide, or tin oxide. The gas sensitive part is formed by sintering after drying. A CO detection value as a first phenomenon detection value is generated from a detection signal from the CO detection unit 10. Here, the CO concentration is used as the CO detection value, but the conversion from the detection signal to the CO detection value may be performed on the CO detection unit 10 side or may be performed on the controller 30 side.

  The smoke detection unit 20 is configured by, for example, a scattered light type smoke sensor having a smoke sensing function. A scattered light type smoke sensor consists of a light emitting part and a light receiving part (not shown), and utilizes the scattering phenomenon that occurs when light from the light emitting part hits smoke particles, and the photocurrent generated when the light receiving element of the light receiving part receives the scattered light. Change, that is, a change in the amount of transmitted light is detected. A smoke detection value as a second phenomenon detection value is generated from the detection signal from the smoke detection unit 20. Here, the smoke density (the light attenuation rate per unit distance) is used as the smoke detection value, but the conversion from the detection signal to the smoke detection value may be performed on the smoke detection unit 20 side or the controller. It may be performed on the 30th side.

  The controller 30 is substantially constituted by a microcomputer, and various functions are created. In particular, the functions related to the present invention include an evaluation unit 31 that evaluates the CO concentration (CO detection value) and smoke concentration (smoke detection value) based on the fire alarm determination condition and outputs a fire alarm notification command; First time point when the concentration exceeds the CO concentration warning threshold value: t1 and second time point when the smoke concentration exceeds the smoke concentration warning threshold value: t2 Reference time: ΔT (= t2-t1) Based on the reference time and the reference detection value Xt2 that is the CO concentration after the second time point, the fire alarm determination condition used in the evaluation unit 31 is adjusted and set based on the time management unit 32 that manages the time such as Fire alarm determination condition adjustment unit 33. The CO concentration warning threshold and the smoke concentration warning threshold are stored in advance in a non-volatile memory or the like, but can be rewritten as necessary.

  For example, when the smoke concentration rises in a very short period of time and the smoke concentration exceeds the smoke concentration warning threshold value while the CO concentration does not exceed the CO concentration warning threshold value, “t2− Since the calculation of “t1” cannot be performed, the time management unit 32 sets the reference time to the shortest time, here zero (ΔT = 0).

In this embodiment, as the fire alarm determination condition, the generation of the smoke concentration of the alarm threshold value w2 or more and the accumulation time: CT that is the permissible time of the generation is adopted, but these determination conditions are: It is determined by the combination of the reference time: ΔT and the reference detection value: Xt2. That is, if the reference time and the reference detection value are used as parameters, the smoke concentration alarm threshold value W2 is derived as a function F, and the reference time and the reference detection value are used as parameters as a storage time CT. ,
w2 = F (ΔT, Xt2)
CT = G (ΔT, Xt2)
It is expressed by the relational expression. The function F and the function G can be obtained by an experimental and statistical method. In this embodiment, the fire alarm determination condition adjusting unit 33 obtains the relationship between the reference time, the reference detection value, and the alarm threshold value obtained from the function F, and the reference time, the reference detection value, and the accumulation time obtained from the function G. Are registered in the form of a table.

  FIG. 2 shows an example of a table relating to the alarm threshold value (unit:% / m) of the smoke density. The standard smoke concentration alarm threshold is about 10% / m, but if the reference time is less than 1 minute and the CO concentration is 110 ppm or more, and if the reference time is more than 1 minute and less than 500 minutes, fire As the possibility of this is high, the alarm threshold for smoke concentration is lowered below the standard value to provide early fire notification. In particular, when the reference time is 5 minutes or more and less than 500 minutes and the CO concentration is 110 ppm or more, the smoke concentration alarm threshold is lowered to 7.5% / m because the possibility of fire is the highest. .

  FIG. 3 shows an example of a table relating to the accumulation time (unit: seconds). The standard accumulation time is about 15 seconds, but when the reference time is shorter than 1 minute and the CO concentration is 110 ppm or more, when the reference time is 1 minute or more and less than 5 minutes, and the CO concentration is 110 ppm or more, and When the reference time is 5 minutes or more and less than 500 minutes, it is assumed that there is a large possibility of fire, and the accumulation time is reduced to provide early fire notification. In particular, when the reference time is 1 minute or more and less than 500 minutes and the CO concentration is 110 ppm or more, the accumulation time is shortened to 5 seconds because the possibility of fire is the highest.

  In the graph of FIG. 4, the change curve of the CO concentration at the time of burning firewood based on the experimental result is indicated by a solid line, and the change curve of the smoke concentration is indicated by a broken line. The horizontal axis represents elapsed time (seconds), the left vertical axis represents smoke concentration (% / m), and the right vertical axis represents CO concentration (ppm). The operation of the controller 30 will be described in detail below using this graph. The evaluation unit 31 determines whether the obtained CO concentration does not reach the CO concentration warning threshold value: u (here, 100 ppm) and the smoke concentration does not reach the smoke concentration warning threshold value: w1 (here, 5% / m). Check it out. The time management unit 32 determines the elapsed time when the CO concentration reaches the CO concentration warning threshold (first time): t1, and the time when the smoke concentration reaches the smoke concentration warning threshold (second time). Reference time: ΔT is obtained from the difference (t2−t1) from the elapsed time: t2. If only the second time point is obtained without the first time point, ΔT = 0. In FIG. 4, ΔT is about 12 minutes. The fire alarm determination condition adjustment unit 33 uses the reference time: ΔT obtained from the time management unit 32 and the CO concentration after the second time point: Xt2 obtained from the evaluation unit 31, the tables shown in FIGS. 2 and 3. Then, the smoke concentration alarm threshold value: w2 = 7.5% / m and the accumulation time: CT = 5 seconds are determined and transferred to the evaluation unit 31 as the adjusted fire alarm determination condition. Based on the fire alarm determination condition set in this way, the evaluation unit 31 checks the smoke concentration and the accumulation time, and when the fire alarm determination condition is satisfied, a fire alarm notification command is sent to the alarm drive unit 40. Output.

The control flow of the fire alarm device 1 configured as described above will be described with reference to the flowchart of FIG.
First, as an initial setting, “0” is set to the T1 flag that is turned on when the CO concentration reaches the CO concentration warning threshold value, and is turned on when the smoke concentration reaches the smoke concentration warning threshold value. “0” is set in the T2 flag (# 02). Next, the latest CO concentration: X is acquired (# 04). This CO concentration: X is compared with the CO concentration warning threshold value: u (# 06). If X <u (# 06 Yes branch), the T1 flag is set to "0"(# 08), step Proceed to # 16. If X <u does not hold (# 06 No branch), the contents of the T1 flag are checked (# 10). If the T1 flag is “0” (# 10 Yes branch), the first time point variable: t1 has passed that time. The time, for example, the current time is substituted (# 12), the T1 flag is set to “1” (# 14), and the process proceeds to step # 16. If the T1 flag is not “0” (# 10 No branch), the process proceeds to step # 16.

  In step # 16, the latest smoke density is acquired (# 16). This smoke density: Y is compared with the smoke density warning threshold value: w1 (# 18). If Y <w1 (# 18 Yes branch), the T2 flag is set to “0” (# 20), and an alarm is issued. The reset process is started (# 22). In this alarm reset process, if the alarm process has not been performed yet, nothing is performed as it is, and the process returns to step # 04. If the alarm process is currently being performed, the alarm process is stopped assuming that there is no longer a fire, and the process returns to step # 04.

  If Y <w1 does not hold (# 18 No branch), the contents of the T2 flag are further checked (# 24). If the T2 flag is not “0” (# 24 No branch), the smoke concentration has already reached the smoke concentration warning threshold value and is in a warning state. move on. If the T2 flag is “0” (# 24 Yes branch), it is determined that the second time point has occurred, and “1” is set in the T2 flag (# 26). Subsequently, the contents of the T1 flag are also checked (# 28). If the T1 flag is not "0" (# 28 Yes branch), since the first time point has already occurred, the elapsed time at that point, for example, the current time is substituted for the second time point variable t2 (# 30), A reference time: ΔT is obtained from the arithmetic expression: ΔT = t2−t1 (# 32). The immediately preceding CO concentration obtained in step # 04: X is used as a reference detection value, and this reference detection value: X and the reference time obtained in step # 32: ΔT are used as shown in FIG. The smoke density alarm threshold value w2 is determined with reference to the table (# 36), and the storage time CT is determined with reference to the table as shown in FIG. 3 (# 38).

  When the smoke concentration alarm threshold value: w2 and the accumulation time: CT are determined as the fire alarm determination condition, it is determined whether or not the fire alarm is finally notified in the alarm system in the routine after step # 40. Done. First, as a check of the first fire alarm determination condition, the latest smoke concentration: Y is compared with the smoke concentration alarm threshold value: w2 (# 40). If Y <w2 (# 40 Yes branch), it is determined that the fire alarm determination condition is not satisfied, the timer flag is set to “0” (# 41a), and the timer is reset (# 41b). Further, after the alarm reset process described above (# 42), the process returns to step # 4. If Y <w2 is not satisfied (# 40 No branch), it is determined that the first fire alarm determination condition is satisfied, and the second fire alarm determination condition check routine is entered. First, in order to check whether or not the second fire alarm determination condition check routine has already been entered, the contents of the timer flag are examined (# 43). If the timer flag is “0” (# 43 Yes branch), in order to start the second fire alarm determination, the timer is started (# 43a), and the timer flag is set to “1” (# 43b). If the timer flag is “1” (# 43 No branch), since the second fire alarm determination has already been started, the processing of steps # 43a and # 43b jumps. Next, the timer time of the timer started in step # 43a is compared with the accumulation time: CT (# 44). If the timer time> CT is not satisfied (# 44 No branch), it is determined that the second fire alarm determination condition is not satisfied, the above-described alarm reset process is performed (# 42), and the process returns to step # 4. If timer time> CT is established, the latest smoke density: Y continues for more than the accumulation time, and the smoke density alarm threshold value: w2 has been reached (# 44 Yes branch), so the first and second fire alarm judgments Assuming that the conditions are satisfied, the alarm processing is started (# 46). In this alarm processing, a fire alarm notification command is output from the evaluation unit 31 to the alarm driving unit 40, and a fire alarm is notified through an alarm means 50 such as a buzzer, a lamp, and an audio output device. This alarm process is continued until the alarm reset process is entered.

  In the fire alarm device 1 described above, the fire alarm determination condition is changed depending on the transition time (reference time) of each of the CO concentration and smoke concentration to a predetermined value (reference time) and the fluctuation of the CO concentration (reference detection value). Appropriate appropriate fire alarm determination conditions can be used, and an early fire alarm can be notified accurately.

[Another embodiment]
In the embodiment described above, the fire alarm determination condition adjusted by the reference time and the reference detection value in each case is the smoke concentration alarm threshold value: w2 and the accumulation time: CT. It is also possible to set only the alarm threshold value w2 or the storage time CT. Flow of control in the fire alarm device 1 in the previous first embodiment and flow of control in the fire alarm device 1 in the second embodiment in which the fire alarm determination condition is set to only the smoke concentration alarm threshold value w2. The difference is shown in FIG. In the second embodiment, since the fire alarm determination using the accumulation time: CT is not performed, the process of calculating the accumulation time: CT in step # 38 in FIG. 5 is omitted. In step # 40, if Y <w2 (# 40 Yes branch), as in the first embodiment, it is determined that the fire alarm determination condition is not satisfied, and the above-described alarm reset process is performed (# 42). Return to step # 4. If Y <w2 is not satisfied, the latest smoke concentration: Y has reached the smoke concentration alarm threshold value: w2 (# 40 No branch), so the fire alarm judgment condition is satisfied and an immediate alarm is issued. The process is started (# 46).

  FIG. 7 shows the flow of control in the fire alarm device 1 in the previous embodiment and the flow of control in the fire alarm device 1 in the third embodiment in which the fire alarm determination condition is only the accumulation time: CT. Has been. In the second embodiment, since a predetermined value fixed as the smoke concentration alarm threshold value w2 is used, the process of calculating the smoke concentration alarm threshold value w2 in step # 36 in FIG. 5 is omitted. Instead, a predetermined value is set as the smoke density alarm threshold value w2 in step # 02 as an initial setting.

  The present invention detects a plurality of phenomena caused by a fire such as smoke and CO, adjusts a fire alarm judgment condition based on the behavior of detected values of these phenomena, and fire alarm based on the adjusted fire alarm judgment condition It can be used as a fire alarm to alert you.

The functional block diagram in 1st Embodiment of the fire alarm by this invention Explanatory drawing explaining the table which determines the alarm threshold value of smoke density from a reference measurement value and a reference time Explanatory drawing explaining the table which determines accumulation | storage time from a reference measured value and reference time Graph showing CO concentration change curve and smoke concentration change curve at the time of firewood burning The flowchart which shows operation | movement of the fire alarm in 1st Embodiment. The partial flowchart which shows the operation | movement of the fire alarm in 2nd Embodiment. Partial flowchart which shows operation | movement of the fire alarm in 3rd Embodiment.

Explanation of symbols

1: Fire alarm 10: CO detector (first fire phenomenon detector)
20: Smoke detection unit (second fire phenomenon detection unit)
30: Controller 31: Evaluation unit 32: Time management unit 33: Fire alarm determination condition adjustment unit 40: Alarm drive unit 50: Alarm means

Claims (5)

A first fire phenomenon detection unit for detecting a first phenomenon caused by a fire;
A second fire phenomenon detection unit for detecting a second phenomenon different from the first phenomenon;
The first phenomenon detection value corresponding to the detection signal of the first fire phenomenon detection unit and the second phenomenon detection value corresponding to the detection signal of the second fire phenomenon detection unit are evaluated based on the fire alarm determination condition, and fire An evaluation unit that outputs an alarm notification command;
An elapsed time between a first time point at which the first phenomenon detection value exceeds a warning threshold value for the first phenomenon and a second time point at which the second phenomenon detection value exceeds a warning threshold value for the second phenomenon. A fire alarm determination condition adjusting unit that adjusts the fire alarm determination condition based on a reference time and a reference detection value that is a detection value of the first phenomenon after the second time point;
With
Wherein one of the fire alarm determination condition is a warning threshold value for the second phenomenon, fire detection value of the second phenomenon Ru said fire alarm notification command is output when it exceeds the alarm threshold Alarm. The fire alarm according to claim 1 , wherein the alarm threshold value is a function value of the reference time and the reference detection value, and the function value is tabulated and registered. One of the fire alarm determination conditions is an accumulation time as a countdown time from the second time point as a starting point until the fire alarm notification command is output, and an elapsed time from the second time point exceeds the accumulation time. fire alarm according to claim 1 or 2 fire alarm notification command is output when the. The fire alarm according to claim 3 , wherein the accumulation time is a function value of the reference time and the reference detection value, and the function value is registered in a table form. The fire alarm according to any one of claims 1 to 4 , wherein the first fire phenomenon detection unit is a CO detection unit that detects CO, and the second fire phenomenon detection unit is a smoke detection unit that detects smoke. vessel.

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