Smoke sensor

Abstract

To obtain a smoke sensor that can suppress generation of a non-fire alarm due to moisture.SOLUTION: A smoke sensor is installed in a fire monitoring environment, and comprises a control unit that determines whether or not smoke is generated in the fire monitoring environment based on a received amount of first light emitted from a light-emitting element for smoke detection, and outputs a smoke detection signal when it is determined that the smoke is generated. The smoke sensor further comprises a light-emitting element for moisture detection that emits second light having a wavelength which is absorbed by moisture. The control unit has a moisture amount estimation function that estimates a moisture content in the fire monitoring environment from a received amount of the second light emitted from the light-emitting element for moisture detection.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY The present disclosure relates to a smoke detector that optically detects smoke generated within a fire monitoring environment. [Background technology]

[0002] Conventionally, when a smoke detector is installed in a location close to a source of steam, such as a bathroom, there is a risk that steam that enters the smoke detector may reach the smoke detection section and cause a false fire alarm. Therefore, there are smoke detectors that are designed to suppress false alarms caused by steam (see, for example, Patent Documents 1 and 2).

[0003] The smoke detectors disclosed in Patent Documents 1 and 2 have a two-stage light-shielding structure in which the smoke detection section and the smoke introduction section are separated into upper and lower sections. The smoke detector in Patent Document 1 prevents false detections caused by steam or dust and reduces false fire alarms by lengthening the smoke introduction path in the vertical direction.

[0004] The smoke detector in Patent Document 2 has a hill-shaped section that protrudes from below toward the smoke detector at the center of the smoke inlet section, and rotates and raises the outside air taken into the smoke inlet section in one direction, and introduces it into a smoke detector chamber provided inside the smoke detector. As a result, a thin smoke detector that is short in the vertical direction is realized, which does not take up space even in a small space, while preventing false fire alarms from being generated by steam from a bathroom, etc., or dust from a warehouse, etc. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-67067 A [Patent Document 2] JP 2020-135780 A Summary of the Invention [Problem to be solved by the invention]

[0006] The smoke detectors disclosed in Patent Documents 1 and 2 both employ a two-stage light-shielding structure to prevent steam from being introduced into the smoke detector. However, even if the detector has a two-stage light-shielding structure, there is a risk of false fire alarms if steam reaches the smoke detector in an installation environment where a large amount of steam is generated.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a smoke detector that can suppress false fire alarms caused by moisture. [Means for solving the problem]

[0008] The smoke detector of the present disclosure is a smoke detector that is installed in a fire monitoring environment and is equipped with a control unit that determines whether smoke has occurred in the fire monitoring environment from the received amount of first light emitted from a smoke detection light-emitting element and outputs a smoke detection signal if it determines that smoke has occurred.The smoke detector further includes a moisture detection light-emitting element that emits second light having a wavelength that is absorbed by moisture, and the control unit has a moisture content estimation function that estimates the moisture content in the fire monitoring environment from the received amount of the second light emitted from the moisture detection light-emitting element. Effect of the Invention

[0009] According to the present disclosure, it is possible to obtain a smoke detector that can suppress false fire alarms caused by moisture. [Brief description of the drawings]

[0010] [Figure 1] 1 is a functional block diagram of a smoke detector according to a first embodiment of the present disclosure. [Diagram 2] 4 is an explanatory diagram showing the amount of light received by the light receiving element 103 according to the first embodiment of the present disclosure in normal operation, when smoke is generated, and when moisture is generated. FIG. [Diagram 3] 1 is an explanatory diagram showing a first example arrangement of elements used in a smoke sensor according to a first embodiment of the present disclosure; [Figure 4]10 is an explanatory diagram showing a second example arrangement of elements used in the smoke sensor according to the first embodiment of the present disclosure. FIG. [Diagram 5] 11 is an explanatory diagram showing a third example arrangement of elements used in the smoke sensor according to the first embodiment of the present disclosure. FIG. [Figure 6] 4 is an explanatory diagram regarding the operation when condensation occurs in the smoke detector according to the first embodiment of the present disclosure. FIG. [Figure 7] 4 is an explanatory diagram relating to light emission timing of a smoke detection light emitting element and a moisture detection light emitting element according to the first embodiment of the present disclosure. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, preferred embodiments of the smoke detector of the present disclosure will be described with reference to the drawings. The smoke detector of the present disclosure has a configuration that can electrically detect when moisture has entered the smoke detection section, and has a technical feature that suppresses the occurrence of false alarms caused by steam, etc. based on the detection results.

[0012] Embodiment 1 1 is a functional block diagram of a smoke detector according to the first embodiment of the present disclosure. The smoke detector 100 according to the first embodiment includes a smoke detection light emitting element 101, a moisture detection light emitting element 102, a light receiving element 103, and a control unit 110.

[0013] The smoke detection light emitting element 101 is an element that emits a first light used to determine whether or not smoke has occurred in a fire monitoring environment, while the moisture detection light emitting element 102 is an element that emits a second light having a wavelength that is absorbed by moisture.

[0014] More specifically, the wavelength component of the first light is suitably in the range of 600 nm to 1050 nm, and the wavelength component of the second light is suitably in the range of 1400 nm to 1600 nm.

[0015] The light receiving element 103 outputs an electric signal according to the amount of the first light emitted from the smoke detection light emitting element 101 that is scattered by smoke, steam, etc. and enters the light receiving element 103, and the amount of the second light emitted from the moisture detection light emitting element 102 that enters the light receiving element 103 as direct light or reflected light. That is, the light receiving element 103 outputs a larger electric signal as the amount of received light increases.

[0016] The second light having a wavelength in the range of 1400 nm to 1600 nm is absorbed by moisture in a larger amount than the first light, so the amount of the second light received by the light receiving element 103 decreases as the amount of moisture increases, and the electrical signal output from the light receiving element 103 decreases in accordance with the amount of light received.

[0017] The control unit 110 is configured to include a smoke detection function 111 and a moisture content estimation function 112. The smoke detection function 111 determines whether or not smoke has occurred in the fire monitoring environment based on the amount of light received by the light receiving element 103 as scattered light out of the first light emitted from the smoke detection light emitting element 101, and outputs a smoke detection signal when it is determined that smoke has occurred. This smoke detection function 111 is substantially the same as that provided in conventional smoke detectors.

[0018] However, light scattering can be caused not only by smoke particles but also by steam, condensation, etc. Therefore, with only the smoke detection function 111, for example, scattered light occurs when steam enters the smoke detection section, and an amount of received light exceeding a predetermined threshold is incident on the light receiving element 103, which may result in a smoke detection signal being output even when no smoke is being generated, resulting in a false detection.

[0019] Therefore, in order to prevent false fire alarms caused by steam, condensation, etc., which are sources of false alarms, smoke detector 100 according to the first embodiment further includes moisture content estimation function 112. Moisture content estimation function 112 estimates the moisture content in the fire monitoring environment from the amount of light received by light receiving element 103 as direct light or reflected light out of the second light emitted from moisture detection light emitting element 102.

[0020] Therefore, specific operations of the smoke detection function 111 and the moisture amount estimation function 112 will be described with reference to Fig. 2. Fig. 2 is an explanatory diagram showing the amount of light received by the light receiving element 103 according to the first embodiment of the present disclosure in normal operation, when smoke is generated, and when moisture is generated.

[0021] Here, "normal" refers to a normal state in which no smoke, steam, condensation, etc. is occurring within the fire monitoring environment, "when smoke is occurring" refers to a state in which smoke is occurring within the fire monitoring environment and a smoke detection signal should be output, and "when moisture is occurring" refers to a state in which steam, condensation, etc. is occurring within the fire monitoring environment but no smoke is occurring and therefore a smoke detection signal should not be output.

[0022] 2, the output level corresponding to the amount of the first light received by the light receiving element 103 is shown as a diagonally hatched bar graph, and the output level corresponding to the amount of the second light received by the light receiving element 103 is shown as a white bar graph for each of the normal state, the state when smoke is generated, and the state when moisture is generated. Above each bar graph, a specific numerical value of the output level is shown as an example.

[0023] The smoke detection light emitting element 101, the moisture detection light emitting element 102, and the light receiving element 103 are each installed in a smoke detection section within the smoke sensor 100. In Fig. 2, the amounts of light received when a first light emitted from the smoke detection light emitting element 101 and a second light emitted from the moisture detection light emitting element 102 are incident on the light receiving element 103 are shown when the inside of the smoke detection section is in a normal state, when smoke is being generated, and when moisture is being generated, respectively.

[0024] 2(A) shows the amount of light received by the light receiving element 103 under normal circumstances. Although the first light emitted from the smoke detection light emitting element 101 under normal circumstances is not scattered by smoke, a small amount of light is reflected inside the smoke detection unit and enters the light receiving element 103, and an output level corresponding to the amount of light received is obtained. The output level of the light receiving element 103 regarding the first light under normal circumstances is desirably about 6 to 20% of the maximum output level.

[0025] On the other hand, the second light emitted from the moisture detection light emitting element 102 under normal circumstances is incident on the light receiving element 103 as direct light or reflected light, and an output level corresponding to the amount of received light is obtained. Under normal circumstances, since the moisture content is low, most of the second light is incident on the light receiving element 103 without being absorbed by moisture. It is desirable that the output level of the light receiving element 103 regarding the second light under normal circumstances is higher.

[0026] 2(B) shows the amount of light received by the light receiving element 103 when smoke is generated. When smoke is generated, the first light emitted from the smoke detection light emitting element 101 is scattered by smoke particles inside the smoke detection unit, resulting in an increase in the amount of light received by the light receiving element 103 and an output level higher than normal. It is desirable that the output level of the light receiving element 103 for the first light when smoke is generated be 50% or more of the maximum output level.

[0027] On the other hand, the second light emitted from the moisture detection light emitting element 102 when smoke is generated is scattered and diffused inside the smoke detection unit in the same manner as the first light, and as a result, the amount of light received by the light receiving element 103 increases, and the output level becomes higher than usual. The output level of the light receiving element 103 for the second light when smoke is generated becomes equal to or higher than the output level of the light receiving element 103 for the first light.

[0028] 2C shows the amount of light received by the light receiving element 103 when moisture is generated. When moisture is generated, the first light emitted from the smoke detection light emitting element 101 is scattered by water molecules and condensation inside the smoke detection unit, and as a result, the amount of light received by the light receiving element 103 increases, and the output level becomes higher than normal.

[0029] On the other hand, when moisture is generated, the second light emitted from the moisture detection light emitting element 102 has a wavelength absorbed by water molecules or condensation, reducing the amount of light received by the light receiving element 103, and the output level becomes lower than under normal circumstances and when smoke is generated.

[0030] If the output level of the light receiving element 103 is equal to or higher than a first threshold when a first light is emitted from the smoke detection light emitting element 101, the smoke detection function 111 in the control unit 110 can determine that an increased amount of the first light received due to scattering has occurred within the smoke detection unit.

[0031] In the specific example shown in FIG. 2, for example, by setting the first threshold value to 200, the smoke detection function 111 can determine whether or not it is a normal state in which the influence of scattering is small, based on the output level of the light receiving element 103 when the first light is emitted from the smoke detection light emitting element 101.

[0032] However, when the smoke detection function 111 determines that the output level of the light receiving element 103 is not normal because it is equal to or higher than the first threshold, it cannot distinguish whether the current state is "smoke generation" where scattering is caused by smoke particles, or "moisture generation" where scattering is caused by water molecules or condensation. Therefore, the smoke sensor 100 according to the first embodiment further includes a moisture amount estimation function 112 to enable this distinction.

[0033] When the second light is emitted from the moisture detection light emitting element 102, the moisture content estimation function 112 in the control unit 110 can determine, based on the comparison result between the output level of the light receiving element 103 and the second threshold value, that if the output level is less than the second threshold value, that the wavelength of the second light has been absorbed due to the influence of moisture generated in the smoke detection unit, resulting in a decrease in the amount of the second light received.

[0034] In the specific example shown in FIG. 2, for example, the second threshold is set to 300, which is the amount of second light received under normal circumstances, and the moisture content estimation function 112 can distinguish whether "smoke is being generated" or "moisture is being generated" based on the output level of the light receiving element 103 when the second light is emitted from the moisture detection light emitting element 102.

[0035] Here, the amount of second light received during normal times may be set according to the situation, such as the amount of second light received one hour ago from the present, or the maximum amount of second light received in the past 24 hours, etc. In other words, the second threshold value may be set in advance according to the fire monitoring environment, or may be dynamically set during fire monitoring according to the fire monitoring environment.

[0036] Therefore, by utilizing the smoke detection function 111, the control unit 110 can determine that a state of "smoke generation" or "moisture generation" is occurring because the output level of the light receiving element 103 becomes equal to or higher than the first threshold value as a result of the emission of the first light from the smoke detection light emitting element 101.

[0037] Furthermore, when the control unit 110 determines that the state is "smoke generated" or "moisture generated", it can utilize the moisture content estimation function 112 to determine that the state is "smoke generated" if the output level of the light receiving element 103 when the second light is emitted from the moisture detection light emitting element 102 is equal to or higher than the second threshold, and determine that the state is "moisture generated" if the output level is less than the second threshold, and can distinguish between "smoke generated" and "moisture generated".

[0038] When the control unit 110 determines that "moisture has been generated" by utilizing the moisture amount estimation function 112, it is possible to prevent false fire alarms caused by moisture by not outputting a smoke detection signal.

[0039] In the above-mentioned specific example, the first threshold is set to 200, and the second threshold is set to 300, which is the normal amount of received light, to distinguish between "smoke generation" and "moisture generation." However, it is also possible to set a value other than the normal amount of received light as the second threshold. In this case, in the example of FIG. 2, it is considered to set the second threshold to a constant value between 150 and 400.

[0040] It is also possible to employ a discrimination method other than setting the second threshold. As a specific example of a discrimination method other than setting the second threshold, it is also possible to discriminate between "smoke generation" and "moisture generation" by calculating an output difference, an output ratio, an output magnitude comparison, or the like as a result of comparing two outputs, the output of the light receiving element 103 when the smoke detection light emitting element 101 emits a first light and the output of the light receiving element 103 when the moisture detection light emitting element 102 emits a second light.

[0041] That is, the control unit 110 can distinguish whether "smoke is occurring" or "moisture is occurring" in the fire monitoring environment by using any of the following methods. Method 1: A method that identifies fires by comparing the estimated moisture content with a threshold value that is preset according to the fire monitoring environment or a threshold value that is dynamically set according to the fire monitoring environment. Method 2: A method of identification based on the results of comparing the amount of first light received with the amount of second light received.

[0042] Next, a specific example of the arrangement of the smoke detection light emitting element 101, the moisture detection light emitting element 102, and the light receiving element 103 will be described with reference to FIGS. 3 to 6, along with a supplementary explanation of the smoke detection function 111 and the moisture amount estimation function 112.

[0043] The positional relationship between the smoke detection light emitting element 101 and the light receiving element 103 is the same as that of a conventional smoke detector. That is, as shown in Fig. 2 above, the smoke detection light emitting element 101 is positioned so that the light scattered by smoke particles is easily incident on the light receiving element 103 when "smoke is generated," and so that direct light is less likely to be incident on the light receiving element 103 when "normally."

[0044] Meanwhile, a supplementary explanation will be given on the arrangement of the moisture detection light emitting element 102, which is newly added in the present embodiment 1. As shown in Fig. 2 above, in order for the moisture amount estimation function 112 to distinguish "when moisture is generated" from other states with high accuracy, it is important to arrange the moisture detection light emitting element 102 and the light receiving element 103 so that the output level corresponding to the amount of the second light received by the light receiving element 103 is reliably equal to or higher than the second threshold value in "normal times" and "when smoke is generated" when the influence of moisture is relatively small.

[0045] Therefore, the moisture detection light emitting element 102 and the light receiving element 103 are positioned so that under "normal conditions", the second light emitted from the moisture detection light emitting element 102 is incident on the light receiving element 103 either as direct light or as reflected light reflected by an optical table or the like within the sensor body.

[0046] Fig. 3 is an explanatory diagram showing a first arrangement example of the elements used in the smoke detector according to the first embodiment of the present disclosure. As shown in Fig. 3, the moisture detection light emitting element 102 is arranged in a direction facing the light receiving element 103, i.e., so that the scattering angle θ is 90 degrees or less. Here, the scattering angle θ is an angle defined by the optical axis of the moisture detection light emitting element 102 and the optical axis of the light receiving element 103, as shown in Fig. 3.

[0047] By arranging the moisture detection light emitting element 102 and the light receiving element 103 so that the scattering angle θ is 90 degrees or less, it is possible to obtain an output level equivalent to the amount of the second light received by the light receiving element 103 that is equal to or greater than the second threshold value during "normal" and "smoke generation" conditions when the effect of moisture is relatively small.

[0048] Furthermore, by appropriately setting the second threshold value, the control unit 110 can reliably determine a state in which the output level has been reduced due to the generation of steam, condensation, or the like in the smoke detection unit.

[0049] Fig. 4 is an explanatory diagram showing a second example of arrangement of the elements used in the smoke detector according to the first embodiment of the present disclosure. In the second example of arrangement shown in Fig. 4, the smoke detection light emitting element 101 and the light receiving element 103 are the same as those in the first example of arrangement shown in Fig. 3, but the moisture detection light emitting element 102 is arranged to face the light receiving element 103 with a scattering angle θ of 0 degrees.

[0050] Even when this second arrangement example is adopted, by appropriately setting the second threshold value, it is possible to reliably determine a state in which the output level has decreased due to the generation of steam, condensation, etc. within the smoke detection unit.

[0051] Fig. 5 is an explanatory diagram showing a third example of arrangement of elements used in the smoke detector according to the first embodiment of the present disclosure. In the third example of arrangement shown in Fig. 5, the smoke detection light emitting element 101 and the light receiving element 103 are the same as those in the first example of arrangement shown in Fig. 3 or the second example of arrangement shown in Fig. 4, but the moisture detection light emitting element 102 is arranged at a position where direct light and reflected light are incident on the light receiving element 103.

[0052] In this third arrangement example, the moisture detection light emitting element 102 is arranged so that most of the second light emitted from the moisture detection light emitting element 102 is reflected by the pillars or walls of the optical table in the sensor body and enters the light receiving element 103. In this way, when reflected light is used, the reduction in the second light due to the influence of moisture can occur over a longer path compared to direct light.

[0053] In addition, when the second light emitted from the moisture detection light emitting element 102 is made incident on the light receiving element 103 as reflected light, the accuracy of estimating the moisture content can be improved by treating the reflective surface on the path of the reflected light, for example by polishing it, to make it more reflective.

[0054] Furthermore, even when this third arrangement example is adopted, by appropriately setting the second threshold value, it is possible to reliably determine a state in which the output level has decreased due to the generation of steam, condensation, etc. within the smoke detection unit.

[0055] Fig. 6 is an explanatory diagram regarding the operation when condensation occurs in the smoke detector according to the first embodiment of the present disclosure. Note that Fig. 6 employs the third arrangement example shown in Fig. 5 above, and illustrates a case where condensation occurs at "part A" at the tip of the wall housing the smoke detection light emitting element 101.

[0056] When condensation occurs, the first light emitted from the smoke detection light emitting element 101 is refracted by the condensation, and the amount of light received by the light receiving element 103 increases, which causes erroneous detection. However, the second light emitted from the moisture detection light emitting element 102 is absorbed by the condensation, which acts to reduce the amount of light received by the light receiving element 103, making it possible to suppress erroneous detection by the action of the moisture amount estimation function 112.

[0057] As explained above using Figures 3 to 6, by devising an appropriate arrangement of the smoke detection light-emitting element 101, the moisture detection light-emitting element 102, and the light-receiving element 103, and by appropriately setting the first threshold value and the second threshold value in accordance with that arrangement, it is possible to operate the smoke detection function 111 and the moisture content estimation function 112 with higher accuracy.

[0058] In addition, it is effective to treat the reflecting surface on the path of the reflected light of the second light so that the reflected light can be easily obtained.

[0059] 3 to 6 show the arrangement examples in which the first light from the smoke detection light emitting element 101 and the second light from the moisture detection light emitting element 102 are acquired as the amount of received light via the common light receiving element 103. However, it is also possible to adopt a configuration in which the light receiving element 103 is provided separately for the first light and the second light.

[0060] Next, a description will be given of the emission timing of the first light emitted from the smoke detection light emitting element 101 and the second light emitted from the moisture detection light emitting element 102. In order to reduce the current consumption of the smoke sensor 100, it is effective to reduce the sampling frequency of the first light and the second light.

[0061] 7 is an explanatory diagram regarding the light emission timing of the smoke detection light emitting element 101 and the moisture detection light emitting element 102 according to the first embodiment of the present disclosure. Fig. 7(A) shows the light emission timing of the first light and the second light during normal monitoring in which monitoring for smoke generation is being performed. Fig. 7(B) shows the light emission timing of the first light and the second light after smoke is detected during normal monitoring.

[0062] During normal monitoring as shown in FIG. 7(A), the control unit 110 controls the light emission timing so that the smoke detection light emitting element 101 emits a first light at intervals of 2 to 3 seconds, and the moisture detection light emitting element 102 emits a second light at intervals of 10 to 15 seconds.

[0063] In this way, current consumption can be reduced by controlling the light emission timing to reduce the sampling frequency of the moisture detection light emitting element 102. Furthermore, when the sampling frequency is reduced and the moisture detection light emitting element 102 is periodically made to emit light, the control unit 110 can self-diagnose whether there is a failure of the moisture detection light emitting element 102 or a break in wiring by checking that an output level is obtained from the light receiving element 103.

[0064] When self-diagnosis is not required, the control unit 110 controls the moisture detection light emitting element 102 not to emit the second light, thereby further reducing current consumption.

[0065] On the other hand, after smoke detection as shown in FIG. 7(B), the control unit 110 can change the light emission timing so that the second light is emitted from the moisture detection light emitting element 102 at intervals of 2 to 3 seconds, similar to the smoke detection light emitting element 101.

[0066] It should be noted that, with regard to the light emission timing during normal monitoring, it is also possible to adopt the pattern shown in Fig. 7(B) instead of the pattern shown in Fig. 7(A). In addition, in the explanation of Fig. 7, the specific light emission intervals are 2 to 3 seconds and 10 to 15 seconds, but these values ​​are merely examples, and appropriate values ​​can be adopted depending on the installation environment, etc.

[0067] Furthermore, these values ​​do not need to be fixed, and the intervals can be variably set according to the magnitude of the electrical signal output from the light receiving element 103 .

[0068] As a result, the control unit 110 can operate the moisture content estimation function 112 at intervals of 2 to 3 seconds, making it possible to more quickly distinguish whether it is "smoke generation" when scattering is occurring due to smoke particles, or "moisture generation" when scattering is occurring due to water molecules or condensation.

[0069] As shown in Figures 7(A) and 7(B), the control unit 110 adjusts the timing of the emission of the first light by the smoke detection light-emitting element 101 and the timing of the emission of the second light by the moisture detection light-emitting element 102 so that they do not overlap, thereby preventing interference between the effects of the first light and the second light and enabling the smoke detection function 111 and the moisture content estimation function 112 to operate more reliably.

[0070] As described above, according to embodiment 1, by having a configuration that further includes a moisture content estimation function in addition to the original smoke detection function, a smoke detector can be realized that can prevent false fire alarms caused by moisture.

[0071] In particular, instead of adopting a two-stage shading structure that makes it difficult for steam and the like to reach, a configuration is adopted that can actively detect electrically when moisture has entered the smoke detection unit. Even if moisture does enter the smoke detection unit in an installation environment where a large amount of steam and the like is generated, it is possible to prevent false fire alarms caused by moisture. [Explanation of symbols]

[0072] 100 Smoke detector, 101 Smoke detection light emitting element, 102 Moisture detection light emitting element, 103 Light receiving element, 110 Control unit, 111 Smoke detection function, 112 Moisture amount estimation function.

Claims

1. A smoke detector is provided in a fire monitoring environment, and includes a control unit that determines whether or not smoke has been generated in the fire monitoring environment based on a received light amount of a first light emitted from a smoke detection light emitting element, and outputs a smoke detection signal when it is determined that smoke has been generated, The moisture detection light emitting element further includes a moisture detection light emitting element that emits a second light having a wavelength that is absorbed by moisture, The control unit has a moisture content estimation function for estimating a moisture content in the fire monitoring environment from the amount of the second light emitted from the moisture detection light emitting element. Smoke detector.

2. When the control unit determines that at least one of steam and condensation has occurred in the fire monitoring environment from a comparison result between the estimated moisture content and a threshold value preset in accordance with the fire monitoring environment or a threshold value dynamically set in accordance with the fire monitoring environment, or from a comparison result between the amount of received first light and the amount of received second light, the control unit does not execute output of the smoke detection signal.

2. The smoke detector of claim 1.

3. When the control unit determines that smoke has been generated from the amount of light received accompanying the emission of the first light by the smoke detection light emitting element, the control unit executes the moisture amount estimation function by emitting the second light by the moisture detection light emitting element, and when it determines that neither the steam nor the condensation has been generated in the fire monitoring environment as a result of executing the moisture amount estimation function, it outputs the smoke detection signal.

3. The smoke detector of claim 2.

4. The control unit adjusts a timing of emitting the first light by the smoke detection light emitting element and a timing of emitting the second light by the moisture detection light emitting element so as not to overlap each other. A smoke detector according to any one of claims 1 to 3.

5. The control unit acquires the first light from the smoke detection light emitting element and the second light from the moisture detection light emitting element as a light receiving amount via a common light receiving element.

5. A smoke detector as claimed in claim 4.

6. The moisture detection light emitting element is disposed so that the second light is reflected within the sensor body and incident on the light receiving element. A smoke detector according to any one of claims 1 to 3.

7. the wavelength of the second light having a wavelength absorbed by moisture is within a range of 1400 nm to 1600 nm; The wavelength of the first light for determining whether smoke has been generated is within the range of 600 nm to 1050 nm. A smoke detector according to any one of claims 1 to 3.

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