JP6858612B2 - Fire alarm - Google Patents

Description

The present invention relates to a fire alarm that detects smoke at the time of a fire and issues a fire alarm.

A conventional fire alarm is described in, for example, Patent Document 1 below. In the fire alarm described in the same document, the light emitted from the light emitting element (“infrared LED element” in the same document) is scattered by smoke particles that have entered the detection region, and the scattered light is scattered by the light receiving element (the same document). A smoke detector that detects and outputs an output signal with the "photodiode element" in the literature, an alarm unit that can issue a fire alarm ("buzzer" in the same document), and an output value based on the output signal is equal to or higher than the alarm threshold. Then, a control unit (“smoke detection alarm circuit” in the same document) for issuing a fire alarm to the alarm unit is provided.

JP-A-2002-197558

By the way, in the above-mentioned conventional technique, foreign matter such as dust may enter the detection area of the smoke detection unit. In that case, even if smoke due to the fire is not generated, the scattered light due to the foreign matter is detected by the light receiving element, which may lead to a false alarm of the fire alarm.

In view of the above circumstances, there is a demand for a fire alarm that can avoid false alarms due to the intrusion of foreign matter into the smoke detection unit.

The fire alarm of the present invention
A smoke detector that scatters the light emitted from the light emitting element with smoke particles that have entered the detection area, detects the scattered light with the light receiving element, and outputs an output signal.
An alarm unit that can issue a fire alarm based on a fire signal,
When the output value based on the output signal becomes equal to or higher than the alarm threshold value, a fire is determined if the smoke condition including the condition that the rate of increase of the output value in the past predetermined period is less than the set rate is satisfied. When the output value becomes equal to or higher than the alarm threshold value, the fire determination is determined as satisfying the foreign matter condition including the condition that the rate of increase of the output value in the past predetermined period is equal to or higher than the set rate. Judgment unit that does not perform,
A control unit that outputs a fire signal to the alarm unit based on the fire determination by the determination unit.
When the foreign matter condition is satisfied, the increase in the output value when the foreign matter condition is satisfied with respect to the reference value of the output value associated with the state where the smoke concentration is zero is added to the alarm threshold value. It is provided with a correction unit that executes a correction process for setting a value as a new alarm threshold value.

According to the present invention, when the output value based on the output signal of the smoke detection unit exceeds the alarm threshold value and the increase in the output value is due to smoke, the output value gradually increases, so that the output value becomes When the rate of increase in the output value in the past predetermined period when the alarm threshold is exceeded is less than the set rate, it is possible to at least tentatively determine that a fire has occurred. On the other hand, when the output value based on the output signal of the smoke detection unit exceeds the alarm threshold value and the increase in the output value is due to a foreign substance, the output value increases sharply, so that the output value exceeds the alarm threshold value. When the rate of increase in the output value in the past predetermined period is equal to or greater than the set rate, it can be at least tentatively determined that no fire has occurred. Therefore, it is possible to avoid a situation in which a fire alarm is immediately issued when a foreign substance enters the smoke detection unit and the output value exceeds the alarm threshold value.
In addition, by increasing the alarm threshold after determining that foreign matter has entered the smoke detection unit, even if foreign matter has entered the smoke detection unit, the actual smoke will occur when smoke is generated by a fire. A fire alarm can be appropriately issued when the concentration reaches the alarm concentration.
As described above, according to the present invention, it is possible to avoid false alarms of fire alarms due to the intrusion of foreign matter into the smoke detection unit.

The fire alarm of the present invention
A smoke detector that scatters the light emitted from the light emitting element with smoke particles that have entered the detection area, detects the scattered light with the light receiving element, and outputs an output signal.
An alarm unit that can issue a fire alarm based on a fire signal,
When the output value based on the output signal becomes equal to or higher than the alarm threshold value, a fire is determined if the smoke condition including the condition that the rate of increase of the output value in the past predetermined period is less than the set rate is satisfied. When the output value becomes equal to or higher than the alarm threshold value, the fire determination is determined as satisfying the foreign matter condition including the condition that the rate of increase of the output value in the past predetermined period is equal to or higher than the set rate. Judgment unit that does not perform,
A control unit that outputs a fire signal to the alarm unit based on the fire determination by the determination unit.
When the foreign matter condition is satisfied, the smoke detection unit subsequently outputs an increase in the output value when the foreign matter condition is satisfied with respect to the reference value of the output value associated with the state where the smoke concentration is zero. It is provided with a correction unit that executes a correction process in which a value obtained by subtracting from an output value based on the output signal is set as a new output value to be compared with the alarm threshold value by the determination unit. is there.
According to the present invention, when the output value based on the output signal of the smoke detection unit exceeds the alarm threshold value and the increase in the output value is due to smoke, the output value gradually increases, so that the output value becomes When the rate of increase in the output value in the past predetermined period when the alarm threshold is exceeded is less than the set rate, it is possible to at least tentatively determine that a fire has occurred. On the other hand, when the output value based on the output signal of the smoke detection unit exceeds the alarm threshold value and the increase in the output value is due to a foreign substance, the output value increases sharply, so that the output value exceeds the alarm threshold value. When the rate of increase in the output value in the past predetermined period is equal to or greater than the set rate, it can be at least tentatively determined that no fire has occurred. Therefore, it is possible to avoid a situation in which a fire alarm is immediately issued when a foreign substance enters the smoke detection unit and the output value exceeds the alarm threshold value.
In addition, when the foreign matter condition is satisfied, the increase in the output value when the foreign matter condition is satisfied with respect to the reference value of the output value associated with the state where the smoke concentration is zero is subsequently output by the smoke detection unit. By executing the correction process in which the value obtained by subtracting from the output value based on the above is set as a new output value to be compared with the alarm threshold in the judgment unit, even if a foreign substance has invaded the smoke detection unit. When smoke is generated due to a fire, a fire alarm can be appropriately issued when the actual smoke concentration reaches the alarm concentration.
As described above, according to the present invention, it is possible to avoid false alarms of fire alarms due to the intrusion of foreign matter into the smoke detection unit.

In the present invention
It is preferable that the smoke condition includes a condition in which the output value becomes equal to or higher than the alarm threshold value and then the state in which the output value becomes equal to or higher than the alarm threshold value continues for a continuous period.

According to the above configuration, when smoke from a fire invades the smoke detection unit, the smoke concentration increases as the fire progresses, so that the output value continues to be equal to or higher than the alarm threshold value. Therefore, after the output value becomes equal to or higher than the alarm threshold value, the rate of increase of the output value in the past predetermined period is less than the set rate, and the state in which the output value is equal to or higher than the alarm threshold value continues for a continuous period. , It is possible to more accurately determine that it is fire smoke. On the other hand, if the rate of increase of the output value in the past predetermined period is less than the set rate after the output value becomes equal to or higher than the alarm threshold value and the output value becomes less than the alarm threshold value within the duration period, smoke other than fire (for example). , Smoke from cigarettes, smoke from cooking, etc.), and it can be determined that a fire alarm is unnecessary.

In the present invention
It is preferable that the control unit is configured to sequentially acquire the output signal from the smoke detection unit at each setting cycle having a length equal to or less than the predetermined period.

According to the above configuration, since the output signal is acquired every appropriately set set cycle, factors such as smoke fluctuation are eliminated, and the rate of increase of the output value based on the output signal can be appropriately obtained. ..

It is a figure which shows the whole of the fire alarm. It is a figure which shows the internal structure of the smoke detection part in a fire alarm, and the control structure. It is a figure which shows typically the correspondence relationship between the smoke density | concentration and the output value in each case where there is no foreign matter invasion into a detection area, and there is a case where there is a foreign matter intrusion into a detection area. It is a figure which shows the mode of increasing the output value with the lapse of time when smoke invades into a smoke detection part. It is a figure which shows the mode of increasing the output value with the lapse of time when a foreign substance invades a smoke detection part. It is a flowchart which shows the flow at the time of giving a fire alarm.

Hereinafter, embodiments that are an example of the present invention will be described with reference to the drawings. FIG. 1 shows a wall-mounted fire alarm as an example. The fire alarm measures the smoke concentration around the installation location and issues a fire alarm based on the measurement result.

As shown in FIG. 1, the fire alarm includes a box-shaped housing 1, an optical detection type smoke detection unit 2 that detects smoke with light, an alarm unit 3 that can issue a fire alarm, and a smoke detection unit 2. A control device 4 that controls the smoke alarm unit 3 and a switch 5 that can stop the fire alarm by manual operation are provided. The smoke detection unit 2, the alarm unit 3, the control device 4, and the switch 5 are each supported by a substrate 6 built in the housing 1.

As shown in FIG. 2, the smoke detection unit 2 includes a light emitting element 11 that emits light based on a light emitting signal, and a light receiving element 12 that detects scattered light in which the light emitted from the light emitting element 11 is scattered by smoke particles. Etc. are provided. The light emitting element 11 is composed of, for example, an LED element. The light receiving element 12 is composed of, for example, a photodiode element.

Further, the smoke detection unit 2 includes an outer frame 14 supported by the housing 1 and having a plurality of slits 13 formed along the circumferential direction, a disk-shaped base material 15 arranged in the outer frame 14, and a base. A plurality of labyrinth walls 17 arranged in a circumferential shape supported on the outer peripheral portion of the material 15, a light-shielding member 18 for preventing light emitted from the light emitting element 11 from directly incident on the light receiving element 12, and a labyrinth wall 17. A mesh-like insect repellent net 19 or the like located between the base material 15 and the like is provided. A light emitting element 11, a light receiving element 12, a labyrinth wall 17, a light shielding member 18, and the like are supported on the base material 15. The area inside the labyrinth wall 17 is the detection area 20.

The light emitting element 11 is arranged at an angle shifted from the diagonal position of the light receiving element 12. Further, the light-shielding member 18 is arranged between the light-emitting element 11 and the light-receiving element 12, and is located on a straight line connecting the light-emitting element 11 and the light-receiving element 12. Further, the outer frame 14 and the labyrinth wall 17 prevent external light from entering the detection area 20.

As shown in FIG. 2, the smoke detection unit 2 takes in smoke particles into the detection area 20 through the gap between the slit 13, the insect net 19, and the labyrinth wall 17 in the event of a fire or the like.

In a state where smoke particles are not taken into the detection region 20, the light receiving element 12 basically does not detect light even if the light emitting element 11 emits light. On the other hand, when smoke particles are taken into the detection region 20 in the event of a fire or the like, the smoke detection unit 2 scatters the light emitted from the light emitting element 11 with the smoke particles that have entered the detection region 20 and scatters the scattered light. The light receiving element 12 detects it and outputs an output signal.

The magnitude of the value of the output signal of the smoke detection unit 2 indicates the scattering intensity, which is the ease with which light is scattered in the detection region 20. The output signal of the smoke detection unit 2 basically has a correlation that changes in conjunction with the smoke concentration around the installation location. The alarm threshold value VT of the output value V based on the output signal, the alarm concentration of the smoke concentration, and the alarm intensity of the scattering intensity have a corresponding relationship. On the other hand, as shown in FIG. 5, when foreign matter such as dust enters the detection area 20 of the smoke detection unit 2, the light of the light emitting element 11 is scattered by the foreign matter in the detection area 20, and the scattered light is received. Since it is detected by the element 12, the value of the output signal is increased. Therefore, the correlation between the output signal and the smoke concentration is different from the case where foreign matter such as dust has not entered the detection area 20.

As shown in FIG. 2, the alarm unit 3 is provided with a buzzer 3A capable of emitting a fire alarm sound and a lamp 3B capable of displaying a fire alarm by changing the lighting state such as color or blinking. There is.

[Control configuration]
As shown in FIG. 2, the control device 4 includes an output adjusting unit 4A that adjusts the output signal of the smoke detecting unit 2 and converts it into an output value V, and an alarm unit 3 based on the output value V of the smoke detecting unit 2. A control unit 4B for controlling, a determination unit 4C for determining conditions such as foreign matter intrusion, a correction unit 4D for correcting parameters related to a fire alarm, and the like are provided.

The output adjusting unit 4A adjusts the output signal of the light receiving element 12 (smoke detecting unit 2) to output the output value V. In this case, the adjustment of the output signal includes, for example, multiplying the output signal by the gain, adding or subtracting the value of the output signal, and the like.

The control unit 4B outputs a light emitting signal to the light emitting element 11 every set cycle ST having a length of a predetermined period T or less, and emits light from the light emitting element 11 every set cycle ST. To add a description, the control unit 4B is configured to sequentially acquire an output signal from the light receiving element 12 of the smoke detection unit 2 at each setting cycle ST having a length of a predetermined period T or less. In the present embodiment, the set cycle ST is the same as the predetermined period T.

Further, the control unit 4B compares the output value V input from the output adjustment unit 4A based on the output signal of the light receiving element 12 with the alarm threshold value VT, and at least receives a fire signal after the output value V becomes equal to or higher than the alarm threshold value VT. It is designed to output and cause the alarm unit 3 to issue a fire alarm.

As shown in FIGS. 3, 4, and 6, the determination unit 4C sets the output value in the past predetermined period T when the output value V based on the output signal of the smoke detection unit 2 becomes equal to or higher than the alarm threshold value VT. A fire is determined if the smoke condition including the condition that the increase rate ΔR of V is less than the set rate RT is satisfied, and when the output value V becomes equal to or higher than the alarm threshold value VT, the output in the past predetermined period T is performed. If the foreign matter condition including the condition that the increase rate ΔR of the value V is equal to or higher than the set rate RT is satisfied, the fire determination is not performed.

As shown in FIGS. 3 and 6, the smoke condition includes a condition that the state in which the output value V is equal to or higher than the alarm threshold VT after the output value V becomes equal to or higher than the alarm threshold VT has continued for the duration Q. ing.

As shown in FIGS. 4 and 6, the foreign matter condition includes a condition that the fluctuation of the output value V is within the specified range W after the output value V becomes equal to or higher than the alarm threshold value VT and continues for the monitoring period R. It has been.

[About the correction part]
When the foreign matter condition is satisfied, the correction unit 4D executes a correction process for increasing the value of the alarm threshold value VT. Specifically, in the present embodiment, the correction unit 4D is based on the increase ΔT of the output value V when the foreign matter condition with respect to the reference value V0 of the output value V associated with the state where the smoke concentration is zero is satisfied. Therefore, the correction process of increasing the value of the alarm threshold value VT as a parameter and setting a new alarm threshold value VT is executed. As an explanation, the alarm threshold value VT plus the increase ΔT of the output value V is set as the new alarm threshold value VT.

The timing at which the fire alarm is issued will be described with reference to FIG. First, it is determined whether or not the output value V is equal to or higher than the alarm threshold value VT (# 1). When the output value V becomes equal to or higher than the alarm threshold VT (# 1: Yes), then whether the increase rate ΔR in the past predetermined period T at the time when the output value V becomes equal to or higher than the alarm threshold VT is equal to or higher than the set rate RT. Whether or not it is determined (# 2).

As shown in FIGS. 3 and 6, when the increase rate ΔR in the past predetermined period T at the time when the output value V becomes equal to or higher than the alarm threshold value VT is less than the set rate RT (# 2: no), then, After the output value V becomes equal to or higher than the alarm threshold value VT, it is determined whether or not the state in which the output value V is equal to or higher than the alarm threshold value VT continues for the duration Q (# 3). If the output value V is equal to or higher than the alarm threshold VT after the output value V becomes equal to or higher than the alarm threshold VT, and the output value V becomes less than the alarm threshold VT without continuing the duration Q (# 3: No), other than fire. It ends as it is smoke etc. On the other hand, if the state in which the output value V is equal to or higher than the warning threshold VT after the output value V becomes equal to or higher than the warning threshold VT continues for the duration Q (# 3: Yes), it is considered that the smoke condition is satisfied and a fire judgment is performed. (# 4), the alarm unit 3 issues a fire alarm (# 5).

On the other hand, as shown in FIGS. 4 and 6, when the rate of increase ΔR in the past predetermined period T at the time when the output value V becomes equal to or higher than the alarm threshold value VT is equal to or higher than the set rate RT (# 2: Yes), the following In addition, it is determined whether or not the state in which the fluctuation of the output value V is within the specified range W continues for the monitoring period R (# 6). If the state in which the fluctuation of the output value V falls within the specified range W does not continue for the monitoring period R (# 6: No), the process ends. On the other hand, if the state in which the fluctuation of the output value V is within the specified range W continues for the monitoring period R (# 6: Yes), it is determined that the foreign matter condition is satisfied, the fire is not determined (# 7), and a fire alarm is issued. Absent.

Then, the value of the alarm threshold value VT as a parameter is increased based on the increase ΔT of the output value V when the foreign matter condition with respect to the reference value V0 of the output value V associated with the state where the smoke concentration is zero is satisfied. The correction process (# 8) for setting a new alarm threshold value VT is executed. As a result, a value obtained by adding the increase ΔT of the output value V to the existing alarm threshold value VT is set as the new alarm threshold value VT. As a result, when a foreign substance has entered the smoke detection unit 2, if the parameter correction process is not performed, the fire alarm is issued at a timing that is too early due to the increase in the output value V due to the foreign substance. By correcting the parameter that increases the value of the alarm threshold VT, the timing at which the fire alarm is issued is delayed so that the fire alarm is appropriately issued after the actual smoke concentration reaches the alarm concentration. Can be done. As a result, it is possible to avoid the occurrence of false alarms for fire alarms.

In this way, whether or not the rate of increase ΔR of the output value V in the predetermined period T is equal to or greater than the set rate RT is used as a material for determining whether or not foreign matter has invaded the smoke detection unit 2. Therefore, in the case of smoke. Can speed up the issuance of fire alarms and delay the issuance of fire alarms in the case of foreign matter, optimize the timing of issuing fire alarms, and cause false alarms. Can be avoided appropriately.

[Another Embodiment]
Hereinafter, another embodiment in which a part of the above embodiment is modified will be described. A plurality of the respective embodiments may be selected and combined as long as there is no contradiction. The scope of the present invention is not limited to the contents shown in each embodiment.

(1) In the above embodiment, the smoke condition includes a condition as to whether or not the state in which the output value V is equal to or higher than the alarm threshold VT after the output value V becomes equal to or higher than the alarm threshold VT has continued for the duration Q. However, the smoke condition is not limited to this, and the smoke condition may not include such a condition. For example, if the increase ΔT by comparing the time point of the reference value V0 and the time point when the value increases from the reference value V0 is less than the set rate RT, a fire judgment may be made and a fire alarm may be issued. Good. This makes it possible to quickly detect fire smoke and issue a fire alarm at an early stage.

(2) In the above embodiment, the foreign matter condition includes a condition in which the fluctuation of the output value V is within the specified range W after the increase rate ΔR becomes the set rate RT or more and continues for the monitoring period R. Although the above is exemplified, the foreign matter condition is not limited to this, and such a condition may not be included in the foreign matter condition. For example, if the rate of increase ΔR of the output value V in the past predetermined period T is equal to or greater than the set rate RT, the foreign matter condition may be satisfied. As a result, it is possible to quickly detect that a foreign substance has entered the smoke detection unit 2.

(3) In the above embodiment, the set cycle ST is the same as that of the predetermined period T, but the present invention is not limited to this. For example, the set cycle ST may be shorter than the predetermined period T.

(4) The above-described embodiment may perform a correction process different from the above-mentioned correction process when the foreign matter condition is satisfied.

(4-1) For example, as a correction process, the correction unit 4D reduces the value of the output value V as a parameter based on the increase ΔT of the output value V with respect to the reference value V0 when the foreign matter condition is satisfied. It may be configured. In this case, the output adjusting unit 4A subtracts the increase ΔT from the existing output value V to calculate a new output value V, and the new output value V is compared with the alarm threshold value VT.

(4-2) Further, for example, even if the correction unit 4D is configured to reduce the value of the output value V as a parameter by reducing the intensity of the light emitted by the light emitting element 11 as the correction process. Good. By reducing the intensity of the light emitted by the light emitting element 11, the intensity of the scattered light detected by the light receiving element 12 also decreases, and as a result, the output signal of the smoke detection unit 2 becomes small, and the output value V becomes small. The value also becomes smaller.

(4-3) Further, for example, the correction unit 4D is configured to reduce the output value V as a parameter by lowering the detection sensitivity of the light receiving element 12 as a correction process. Specifically, in the output adjusting unit 4A, the value of the output value V can be reduced by reducing the gain to be multiplied by the output signal of the light receiving element 12.

(5) In the above embodiment, the control device 4 is connected to a communication system (for example, short-range wireless communication such as a Wifi unit, remote wireless communication such as the Internet), and information on the control device 4 (for example, to the smoke detection unit 2). The presence / absence of foreign matter intrusion, the status of correction processing, the presence / absence of a fire alarm, etc.) may be transmitted to a remote location or the like.

(6) In the above embodiment, the one provided with the insect net 19 is illustrated, but the present invention is not limited to this. For example, the insect net 19 may not be provided.

The present invention can be used for various types of fire alarms such as the above-mentioned wall-mounted type and ceiling-mounted type.

2: Smoke detection unit 3: Alarm unit 4B: Control unit 4D: Correction unit 11: Light emitting element 12: Light receiving element 20: Detection area Q: Duration R: Monitoring period ST: Setting cycle T: Predetermined period V: Output value VT : Alarm threshold W: Specified range RT: Setting rate ΔR: Increase rate

Claims (4)

A smoke detector that scatters the light emitted from the light emitting element with smoke particles that have entered the detection area, detects the scattered light with the light receiving element, and outputs an output signal.
An alarm unit that can issue a fire alarm based on a fire signal,
When the output value based on the output signal becomes equal to or higher than the alarm threshold value, a fire is determined if the smoke condition including the condition that the rate of increase of the output value in the past predetermined period is less than the set rate is satisfied. When the output value becomes equal to or higher than the alarm threshold value, the fire determination is determined as satisfying the foreign matter condition including the condition that the rate of increase of the output value in the past predetermined period is equal to or higher than the set rate. Judgment unit that does not perform,
A control unit that outputs a fire signal to the alarm unit based on the fire determination by the determination unit.
When the foreign matter condition is satisfied, the increase in the output value when the foreign matter condition is satisfied with respect to the reference value of the output value associated with the state where the smoke concentration is zero is added to the alarm threshold value. A fire alarm equipped with a correction unit that executes a correction process that sets a value as a new alarm threshold. A smoke detector that scatters the light emitted from the light emitting element with smoke particles that have entered the detection area, detects the scattered light with the light receiving element, and outputs an output signal.
An alarm unit that can issue a fire alarm based on a fire signal,
When the output value based on the output signal becomes equal to or higher than the alarm threshold value, a fire is determined if the smoke condition including the condition that the rate of increase of the output value in the past predetermined period is less than the set rate is satisfied. When the output value becomes equal to or higher than the alarm threshold value, the fire determination is determined as satisfying the foreign matter condition including the condition that the rate of increase of the output value in the past predetermined period is equal to or higher than the set rate. Judgment unit that does not perform,
A control unit that outputs a fire signal to the alarm unit based on the fire determination by the determination unit.
When the foreign matter condition is satisfied, the smoke detection unit subsequently outputs an increase in the output value when the foreign matter condition is satisfied with respect to the reference value of the output value associated with the state where the smoke concentration is zero. A fire alarm provided with a correction unit that executes a correction process in which a value obtained by subtracting from an output value based on the output signal is set as a new output value to be compared with the alarm threshold value by the determination unit. vessel. The fire alarm according to claim 1 or 2, wherein the smoke condition includes a condition in which the output value is equal to or higher than the alarm threshold value and then the output value is equal to or higher than the alarm threshold value for a continuous period. vessel. The fire according to any one of claims 1 to 3, wherein the control unit is configured to sequentially acquire the output signal from the smoke detection unit at each setting cycle having a length equal to or less than the predetermined period. Alarm.

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