JP7824850B2 - alarm - Google Patents

Description

The present invention relates to an alarm device that detects fires and other emergencies and issues an alarm.

Conventionally, there are alarms that detect smoke generated by a fire, determine whether a fire has occurred, and output an alarm. To detect the smoke, these alarms have a light-emitting element and a light-receiving element as a smoke sensor. The light emitted by the light-emitting element is scattered by the smoke, and this scattered light is detected by the light-receiving element to detect the smoke concentration value and detect smoke. The alarm also has an alarm output unit for outputting the alarm (see, for example, Patent Document 1).

Furthermore, some of these alarms are equipped with various sensors in addition to the light-emitting and light-receiving elements, and the alarm output unit is designed to output alarm sounds other than fire alarms. Examples of such sensors include CO sensors, gas leak sensors, and heat sensors.

Japanese Patent Application Laid-Open No. 2020-21262

While the alarm output from an alarm can clearly communicate an abnormality such as a fire to those nearby, the sound waves generated by the alarm output disrupt the flow of smoke, which is a problem. As a result, conventional alarms are unable to detect normal smoke concentrations while the alarm is sounding, which can lead to false detections and delays in fire detection. This is particularly problematic for alarms equipped with sensors, as they may not be able to correctly detect a fire while the alarm is sounding based on the output of the sensors.

The present invention aims to provide an alarm that can reliably detect smoke even when the flow of smoke is disturbed by sound waves generated by the alarm output.

The present invention is an alarm device comprising a smoke detection unit which has a light receiving element and a light emitting element and detects a smoke density value, a processing unit which makes a fire judgment using at least the smoke density value as one of the judgment factors , and an alarm output unit which is configured to be able to output an alarm by sounding, wherein the processing unit processes the smoke density value and/or a fire judgment based on the smoke density value as invalid in the fire judgment while the alarm output unit is sounding, and the processing unit processes the smoke density value and/or a fire judgment based on the smoke density value at the same time as the alarm output unit starts sounding as valid in the fire judgment .

The present invention may further include a CO sensor for detecting carbon monoxide, and the alarm may include a CO detection alarm. The processing unit may process the smoke density value and/or a fire determination based on the smoke density value as invalid during the time the alarm output unit sounds and outputs the CO detection alarm.

The present invention also allows the processing unit to perform the fire detection and smoke detection unit failure determination using at least the smoke density value as one of the determination factors, and while the alarm output unit is sounding, the processing unit can process the smoke density value and/or a fire detection based on the smoke density value as invalid in the fire detection, and process the smoke density value and/or a failure detection based on the smoke density value as valid in the failure determination.

In this invention, the processing unit processes the smoke density value and/or the fire determination based on the smoke density value as invalid while the alarm output unit is sounding an alarm, thereby enabling stable smoke detection even if the flow of smoke is disrupted by sound waves generated by the sounding of the alarm.

FIG. 2 is a plan view of the base of the fire alarm according to the embodiment of the present invention. FIG. 2 is a plan view of the middle plate of the fire alarm according to the embodiment of the present invention, showing the flow of smoke when no sound is being emitted. FIG. 2 is a plan view of the middle plate of the fire alarm according to the embodiment of the present invention, showing the flow of smoke when an audio alarm is sounding. FIG. 2 is a block diagram of a processing unit according to an embodiment of the present invention. FIG. 10 is a diagram showing how a fire is judged during an alarm output according to the present invention.

An embodiment of the present invention will be described with reference to Figures 1 to 4. First, the configuration of a fire alarm 1 will be described with reference to Figures 1 to 3, using as an example a fire alarm 1 equipped with a smoke detection unit 2 and a CO sensor 4. Note that in this embodiment, the front and rear directions are defined based on the state in which the fire alarm 1 is attached to a mounting surface such as a ceiling.

The fire alarm 1 comprises a smoke detection unit 2 and an alarm output unit 3, and in this embodiment, further comprises a CO sensor 4 provided for detecting carbon monoxide, and a power supply means 5 (e.g., a battery, etc.) provided for securing a power source for operating the fire alarm 1. The fire alarm 1 also comprises a housing for housing each of these components.

The housing is composed of a main body 6 and a front cover (not shown) attached to the front side of the main body 6. The main body 6 has a base 7 and a middle plate 8 located on the front side of the base 7, and the front cover is attached to the front side of the middle plate 8.

The base 7 has the circuit board 9 and alarm output unit 3 mounted thereon, and is equipped with the smoke detector 14 of the smoke detector 2 (described below). The middle plate 2 is also equipped with the smoke inlet 15 of the smoke detector 2 (described below), and is equipped with a flow path wall 11 that forms a smoke flow path 10 for introducing smoke S from outside the fire alarm 1 into the smoke inlet 15.

The circuit board 9 is equipped with a light-emitting element 12, a light-receiving element 13, and a CO sensor 4, as well as various other elements such as a microcomputer that constitutes the processing unit 16, as described below. The circuit board 9 is also connected to the alarm output unit 3 and power supply means 5.

The smoke detection unit 2 has a light-emitting element 12 and a light-receiving element 13, and is provided to detect the smoke density value C. The smoke detection unit 2 detects the smoke density value C by having the light-receiving element 13 detect scattered light generated when the light output from the light-emitting element 12 is scattered by smoke S. For this reason, the light-emitting element 12 and the light-receiving element 13 are positioned so that the light from the light-emitting element 12 does not directly enter the light-receiving element 13.

In this embodiment, the smoke detection unit 2 is composed of two stages: a smoke detection unit 14 located on the rear side and a smoke introduction unit 15 located on the front side, with at least the interior of the smoke detection unit 14 acting as a dark box. The light-emitting element 12 and light-receiving element 13 are also provided in the smoke detection unit 14, and are designed to operate intermittently at specified time intervals to conserve power from the power supply means 5. The smoke density value C detected by the light-emitting element 12 and light-receiving element 13 is output to a sampling unit in the processing unit 16, which will be described later.

The alarm output unit 3 is configured to be able to sound alarm A, which will be described later, and is implemented, for example, as a speaker. Examples of alarm A include various alarms such as a fire alarm sound and/or a fire alarm voice (fire alarm) that alerts the occurrence of a fire, and a CO detection alarm and/or a CO detection alarm voice (CO detection alarm) that alerts the CO sensor 4 that it has detected CO. The alarm output unit 3 may be capable of outputting both voice and non-voice sounds (hereinafter referred to as non-voice sounds), such as sounds of a certain frequency or sweep sounds, or it may be capable of outputting only voice or non-voice sounds.

In this embodiment, the alarm output unit 3 is capable of sounding both audio _AV and non-audio _AS (hereinafter, in this embodiment, audio _AV and non-audio _AS will be collectively referred to as alarm A), and for example, sounds non-audio _AS multiple times at predetermined intervals, followed by audio AV. Furthermore, the alarm output unit 3 is configured to sound audio _AV and non-audio AS in response to a fire signal received from the processing unit ₁₆ (in this embodiment, a fire determination unit ₂₀ described later) or a CO detection signal received from the CO sensor 4.

Next, we will explain the configuration of the processing unit 16, which performs fire detection using the smoke density value C detected by the smoke detection unit 2 in this embodiment as one of the determination factors. The processing unit 16 has a sampling unit 17, a recording unit 18, a counter circuit 19, a fire detection unit 20, and a fault detection unit 21.

The sampling unit 17 receives the output from the smoke detection unit 2, compares the smoke density value C based on the output of the smoke detection unit 2 with the fire threshold value Th recorded in the recording unit 18, performs a fire judgment J, and determines whether the smoke density value C is above or below the fire threshold value Th. If the smoke density value C is above the fire threshold value Th, a fire output F is output to the counter circuit 19; if it is below the fire threshold value Th, a non-fire output N is output as the fire judgment result.

On the other hand, although smoke S that reaches the fire alarm 1 is normally introduced into the smoke introduction section 15 via the smoke flow path 10 (see Figure 2A), while the alarm output section 3 is outputting alarm A (in this embodiment, audio _AV or non-audio sound A _S ), due to the influence of the sound waves of alarm A, a portion S ₁ of the smoke S may go around the edge of the housing and not enter the housing, which may result in a normal smoke concentration value C not being detected (see Figure 2B).

Furthermore, depending on the relative positions of the alarm output unit 3 and the smoke detection unit 2, the sound waves of alarm A may act to push out smoke that has entered the smoke detection unit 2, which will also result in the normal smoke concentration value C not being detected. In reality, it takes a certain amount of time for smoke S introduced into the alarm 1 to reach the smoke detection unit 2, so the normal smoke concentration value C can be detected immediately after alarm A begins to sound.

For this reason, the sampling unit 17 processes the smoke density value C as invalid while the alarm output unit 3 is sounding alarm A, and does not output it to the counter circuit 19. In other words, in this embodiment, the processing unit 16 processes the smoke density value C as invalid in fire detection while the alarm output unit 3 is sounding alarm A.

The counter circuit 19 is configured to operate when the smoke concentration value C based on the output of the smoke detection unit 2 is equal to or greater than the fire threshold value Th, based on the fire output F from the sampling unit 17. The fire determination unit 20 determines that a fire has occurred when the counter circuit 19 operates a predetermined number of times while the sampling unit 17 outputs a specified number of times, and outputs a fire signal to at least the alarm output unit 3.

The failure determination unit 21 is provided to determine whether the smoke detection unit 2 has failed based on the smoke density value C, which is derived from the output of the smoke detection unit 2. The failure determination unit 21 outputs a failure signal when it determines that the smoke detection unit 2 has failed. The fire alarm 1 then notifies the outside world of the failure based on the failure signal. The means for this notification can be selected as appropriate; for example, the alarm output unit 3 may output a failure alarm voice and/or sound, or a separate indicator light (not shown) may be provided and turned on.

In this case, the failure determination unit 21 may receive the smoke density value C directly from the smoke detection unit 2, or, as in this embodiment, may receive it via the sampling unit 17. In either case, the failure determination unit 21 processes the smoke density value C as valid even while the alarm output unit 3 is sounding alarm A.

In other words, in this embodiment, the processing unit 16 processes the smoke density value C as valid for failure determination while the alarm output unit 3 is sounding alarm A. Therefore, in the fire alarm 1, it is possible to perform a failure determination for the smoke detection unit 2 even while the alarm output unit 3 is sounding alarm A. Note that when alarm A based on the fire determination is sounding, the smoke density value C is equal to or greater than the fire threshold value Th, so a failure determination for the smoke detection unit 2 is not performed.

Next, fire detection in the fire alarm 1 of this embodiment will be explained with reference to Figure 4, using as an example a fire detection when the alarm output unit 3 is sounding alarm A based on CO detection by the CO sensor. Note that in Figure 4, the dashed line indicates a case where the smoke density value C is invalid, fire detection J is not performed, and a fire detection result is not output from the sampling unit 17 to the counter circuit 19.

The conditions for determining whether a fire has occurred can be set as appropriate, but in the fire alarm 1 of this embodiment, when the alarm output unit 3 is not sounding, the condition for determining whether a fire has occurred is that the counter circuit 19 has operated six times during the eight times that the sampling unit 17 has output a fire determination result to the counter circuit 19.

On the other hand, once the alarm output unit 3 sounds and starts outputting alarm A, the fire detection result is not output to the counter circuit 19 until the alarm output unit 3 stops sounding. Therefore, during this time, the sampling unit 17 outputs the fire detection result to the counter circuit 19 four times, and the counter circuit 19 must have operated three times to determine whether or not a fire is detected. This allows the time required for the fire alarm 1 to make a fire detection to be the same whether or not the alarm output unit 3 is sounding.

When smoke S is introduced into the fire alarm 1 while the alarm output unit 3 is sounding, the light from the light-emitting element 12 is scattered by the smoke S, and this scattered light is detected by the light-receiving element 13, converted into a smoke concentration value C corresponding to the amount of light received, and output to the sampling unit 17.

The sampling unit 17 compares the smoke density value C with the fire threshold Th recorded in the recording unit 18, and outputs either the fire output F or the non-fire output N to the counter circuit 19. For example, in Figure 4, at time i, the smoke density value C is less than the fire threshold Th, so the non-fire output N is output to the counter circuit 19, and from time ii to time xi, the smoke density value C is greater than or equal to the fire threshold Th, so the fire output F is output to the counter circuit 19. The counter circuit 19 operates in response to the input of the fire output F from the sampling unit 17, and turns the counter.

At this time, the sampling unit 17 invalidates the smoke density value C while the alarm output unit 3 is sounding and outputting the CO detection alarm A. In Figure 4, at time h while alarm A is being output, the smoke density value C falls below the fire threshold Th due to the influence of alarm A, but because this value is treated as invalid, it is not output to the sampling unit 19 as a non-fire output N.

When the fire detection unit 20 confirms that the result counter circuit 19 has operated three times out of the last four fire detections J made by the sampling unit 17, i.e., that fire output F has been output three times, it determines that a fire has occurred and outputs a fire signal. In Figure 4, for example, at time iv, fire output F is output a total of three times at time ii, iii, and iv between time i and time iv, and at time iv, the counter circuit 19 has operated three times, resulting in a fire detection.

If the alarm output unit 3 did not invalidate the smoke density value C while sounding, and instead performed a fire detection under the same conditions as when the alarm output unit 3 is not sounding, as with conventional alarms, as shown by the two-dot chain line in Figure 4, at times e and f, if the smoke density value C falls below the fire threshold Th due to the influence of the sound waves from alarm A, just as at time h, a fire detection would not be made until time vi, resulting in a delay in fire detection compared to the above.

In this embodiment, the timing at which the smoke detection unit 1 detects the smoke density value _C and the timing at which the alarm output unit 3 starts to sound are adjusted so that the sampling unit 17 makes a fire judgment just before the alarm output unit 3 starts to sound, i.e., just before each of the audio AV and non-audio _AS is output. In this way, in this embodiment, the number of invalid smoke density values C is reduced, allowing for faster fire judgment.

As described above, in the alarm device 1 of this embodiment, by invalidating the smoke concentration value C while the alarm output unit 3 is sounding during fire detection, it is possible to provide an alarm device 1 that can reliably detect smoke even if the flow of smoke S is disrupted by sound waves generated by the output of alarm A.

A secondary effect of the fire alarm 1 of this embodiment is that, because the smoke density value C continues to be detected even while the alarm output unit 3 is sounding, stable smoke detection can be performed without interrupting judgments other than fire judgments, such as failure judgments of the smoke detection unit 2, when the smoke density value C is used for such judgments. In this case, the failure judgment is performed, for example, as follows:

As mentioned above, the smoke detection unit 2 is positioned so that light from the light-emitting element 12 does not normally enter the light-receiving element 13 directly. However, a small amount of light is incident on the light-receiving element 13 due to reflection within the smoke detection unit 14, and a small, constant detection value is measured by the light-receiving element 13.

If dust or other foreign matter enters the smoke detection unit 14 or if the wall surface of the smoke detection unit becomes soiled, the detection value may be higher than the initial value without exceeding the fire threshold Th. Furthermore, if the light-emitting element 12 or light-receiving element 13 becomes soiled or the light output of the light-emitting element 12 decreases, the detection value may be lower than the initial value.

In this way, if the detection value of the light receiving element 13 remains higher or lower than the initial value for a predetermined period of time, the failure determination unit 21 determines that there is a failure in the smoke detection unit 2. If the sampling unit 17 stops the fire detection itself while the alarm output unit 3 is sounding, failure determination will no longer be performed, but in the case of the alarm device 1 of this embodiment, detection of the smoke concentration value C is still performed, so failure determination of the smoke detection unit 2 can continue.

The present invention is not limited to the above-described embodiments and can be modified as appropriate without departing from the spirit of the invention.

(1) The fire alarm 1 of the above embodiment is one example of an alarm to which the present invention can be applied. The present invention is not limited to the fire alarm 1 and can be applied to various fire alarms as long as they use smoke concentration values as at least one of the factors for fire detection (for example, known smoke-type fire alarms). In particular, the presence or absence of a CO sensor 4 can be selected as appropriate.

(2) The fire detection conditions in the above embodiment are merely examples and can be set appropriately as needed.

(3) In the above embodiment, while the alarm output unit 3 is sounding and outputting alarm A, the smoke density value C detected by the smoke detection unit 2 is treated as invalid. However, the processing unit 16 may be configured to treat the fire judgment made by the fire judgment unit 20 based on the smoke density value C while the alarm output unit 3 is sounding as invalid. It is also possible to treat both the smoke density value C and the fire judgment based on the smoke density value C as invalid.

(4) In the above embodiment, while the alarm output unit 3 is sounding, the smoke density value C and/or the fire determination based on the smoke density value C are treated as invalid. However, it is also possible to treat the smoke density value C and/or the fire determination based on the smoke density value C simultaneously with the alarm output unit 3 starting to sound as valid. This is because at the start of the sounding and immediately thereafter, the smoke density value C of the smoke S introduced into the alarm device 1 is considered to have been detected before the alarm output unit 3 started to sound, and therefore the effect of the sounding of the alarm output unit 3 is either nonexistent or negligible.

(5) The alarm A that can be output by the alarm output unit 3 is not limited to the fire alarm or CO detection alarm, but can also be a variety of other alarms, such as a gas detection alarm, a fire alarm based on factors other than the smoke concentration value C, a fire alarm based on heat (temperature), or an alarm indicating that the power supply means 5 has run out. It is also possible to provide separate sensors for detecting these alarms.

REFERENCE SIGNS LIST 1 Fire alarm 2 Smoke detection unit 3 Alarm output unit 4 CO sensor 5 Power supply means 6 Main body 7 Base 8 Middle plate 9 Substrate 10 Smoke flow path 11 Flow path wall 12 Light-emitting element 13 Light-receiving element 14 Smoke detection unit 15 Smoke introduction unit 16 Processing unit 17 Sampling unit 18 Recording unit 19 Counter circuit 20 Fire determination unit 21 Failure determination unit A Alarm C Smoke density value F Fire output J Fire determination N Non-fire output S Smoke Th Fire threshold

Claims (3)

a smoke detection unit having a light receiving element and a light emitting element and configured to detect a smoke density value;
a processing unit that performs a fire determination using at least the smoke density value as one of the determination factors;
an alarm output unit configured to be able to output an alarm by sounding ,
the processing unit is an alarm device that processes the smoke density value and/or a fire determination based on the smoke density value as invalid in the fire determination while the alarm output unit is sounding,
An alarm device characterized in that, in the fire judgment, the processing unit processes the smoke density value and/or a fire judgment based on the smoke density value at the same time as the alarm output unit starts to sound as valid . further comprising a CO sensor for detecting carbon monoxide;
the alarm includes a CO detection alarm;
An alarm device according to claim 1, characterized in that, while the alarm output section is sounding and the CO detection alarm is being output, the processing section processes the smoke density value and/or a fire judgment based on the smoke density value in the fire judgment as invalid. An alarm device as described in claim 1 or 2, characterized in that the processing unit performs the fire judgment and the smoke detection unit failure judgment using at least the smoke density value as one of the judgment factors, and while the alarm output unit is sounding, the processing unit processes the smoke density value and/or a fire judgment based on the smoke density value as invalid in the fire judgment, and processes the smoke density value and/or a failure judgment based on the smoke density value as valid in the failure judgment.