WO2022209985A1 - Smoke detector - Google Patents

Abstract

The present invention provides a smoke detector that can estimate the presence or absence of condensation without the need for a light-emitting means for detecting condensation. A temperature signal acquisition means 1183 included in a control unit 118 provided for the smoke detector estimates whether condensation has occurred on an object on the basis of a measured value of a thermometer 1121, a measured value of a thermometer 1171, and a measured value of a hygrometer 116. The thermometer 1121 measures a temperature of the object susceptible to condensation in a detection region where the smoke detector detects smoke, the thermometer 1171 measures a temperature of air flowing into the detection region, and the hygrometer 116 measures a humidity of air in the detection region.

Description

Smoke detectors

The present invention relates to technology for sensing smoke.

The sensing area is irradiated with light from a light-emitting element, the scattered light scattered by particles in the air within the sensing area is received by a light-receiving element, and the light-receiving element receives and measures the intensity of the light, which is sensed from the outside space. Smoke detectors (hereinafter referred to as "photoelectric smoke detectors") are known that detect the generation of smoke in an external space by sensing particles contained in air flowing into the area.

　If condensation occurs inside the photoelectric smoke sensor, light scattering occurs due to the dew within the sensing area, and it may be mistaken for light scattering due to smoke generation. In addition, dew condensation on the light-receiving element and the lens that guides the light to the light-receiving element may be misidentified as dirt. Therefore, if it is possible to determine whether condensation has occurred inside the photoelectric smoke sensor, it is possible to reduce the occurrence of erroneous recognition and improve the accuracy of smoke detection and contamination detection.

Patent Document 1, for example, discloses a technique for preventing false detection of smoke due to condensation. Patent Document 1 describes a fire alarm device such as a photoelectric smoke sensor that includes a dew condensation detection light-emitting element for detecting the presence of dew condensation and directly receives at least part of the light emitted from the dew condensation detection light-emitting element. A technique has been proposed in which a light-receiving element is provided at a position where condensation can occur, and dew condensation within the fire alarm system is detected based on the light-receiving output of the light-receiving element.

JP-A-2-18696

In the case of the invention described in Patent Document 1, in addition to the light emitting element for detecting smoke, it is necessary to provide a light emitting element for detecting condensation, which causes disadvantages such as high cost and an increase in the size of the device.

In view of the above circumstances, the present invention provides a smoke sensor capable of estimating the presence or absence of condensation without requiring light emitting means for detecting condensation.

In order to solve the above problems, the present invention provides a smoke sensor that senses the generation of smoke in an external space by sensing particles contained in the air flowing into the sensing area from the external space, the smoke sensor emitting light. light emitting means for receiving light; light receiving means for receiving light; temperature measuring means for measuring temperature; humidity measuring means for measuring humidity; and dew condensation estimating means for estimating the presence or absence of dew condensation within the sensing area.

According to the present invention, it is possible to estimate the presence or absence of condensation within the smoke sensor without requiring a light emitting means for detecting condensation.

The figure which showed the structure of the smoke sensing system which concerns on one Embodiment. The figure which showed typically the structure of the smoke sensor which concerns on one Embodiment. The figure which showed the structure of the computer employ|adopted as the hardware of the control unit which concerns on one Embodiment. The figure which showed the functional structure of the control unit which concerns on one Embodiment. The figure which showed the structure of the dew point temperature data which concerns on one Embodiment. The figure which showed typically the structure of the smoke sensor which concerns on a modification. The figure which showed the functional structure of the control unit which concerns on a modification. The figure which showed the functional structure of the control unit which concerns on a modification. The figure which showed the structure of the computer employ|adopted as the hardware of the control unit which concerns on a modification. The figure which showed typically the structure of the smoke sensor which concerns on a modification. The figure which showed the functional structure of the control unit which concerns on a modification.

[Embodiment]
A smoke sensing system 1 according to an embodiment of the present invention will be described below. FIG. 1 is a diagram showing the configuration of a smoke sensing system 1. As shown in FIG. A smoke sensing system 1 includes a smoke sensor 11 and a host system 12 .

The smoke detector 11 is placed in a space to be monitored for smoke generation (hereinafter referred to as a “monitored space”), takes in air in the monitored space, and detects smoke if the taken-in air contains smoke. , is a device that transmits an alarm of smoke generation to the host system 12 when smoke is detected.

In FIG. 1, the number of smoke sensors 11 provided in the smoke detection system 1 is one, but the number of smoke sensors 11 provided in the smoke detection system 1 varies according to the number and size of the monitored spaces.

The host system 12 may be a monitoring terminal device, a smoke alarm panel, a central monitoring system, or the like. The host system 12 and the smoke sensor 11 are connected for communication via a communication medium that is wired, wireless, or a mixture thereof, and are capable of data communication with each other.

The host system 12 is the same as the host system according to the prior art, so its description is omitted.

FIG. 2 is a diagram schematically showing the configuration of the smoke sensor 11. As shown in FIG. Smoke sensor 11 includes housing 110 , light emitting section 111 , light receiving section 112 , lens 113 , fan 114 , filter 115 , hygrometer 116 , flow meter 117 and control unit 118 .

The housing 110 is a container that forms a space inside. The housing 110 has an intake port P that is an opening that functions as an inlet for air to flow from the external space to the internal space, and an exhaust port that is an opening that functions as an outlet for air to flow from the internal space to the external space. have Q.

In addition, the housing 110 includes a wall 1101 for forming a sensing area S, which is an area for sensing smoke, in the interior space, and a pipe forming an air flow path from the intake port P to the sensing area S. 1102 and a tube 1103 forming an air flow path from the sensing region S to the exhaust port Q. FIG.

The light emitting unit 111 (an example of light emitting means) has an LED, for example, and emits light from the LED to the sensing area S. The light-receiving unit 112 (an example of a light-receiving means) faces the light-emitting unit 111 so that the light emitted from the light-emitting unit 111 does not directly enter the light-receiving unit 111 and the scattered light scattered by the particles in the air in the sensing region S enters. It is placed in a position where it does not The light receiving unit 112 has, for example, a photodiode, receives scattered light within the sensing region S that is focused by the lens 113, and outputs a light intensity signal indicating the intensity of the received light to the control unit 118. do.

A photodiode changes its output value depending on the temperature even if it receives light of the same intensity. Therefore, the light receiving section 112 has a thermometer 1121 (temperature measuring means, an example of a first thermometer) for correcting the output value of the photodiode. Thermometer 1121 measures the temperature of the photodiode and outputs a temperature signal indicating the measured temperature to control unit 118 .

The fan 114 is placed on the air flow path formed by the tube 1102 and serves to generate air flow from the outer space toward the sensing area S by means of rotating blades.

The filter 115 is arranged on the air flow path formed by the pipe 1102, traps dust contained in the air flowing toward the sensing area S from the external space, and prevents dust from entering the sensing area S.

A hygrometer 116 (an example of humidity measuring means) is placed in the sensing area S, measures the relative humidity in the sensing area S, and outputs a humidity signal indicating the measured relative humidity to the control unit 118 . The hygrometer 116 is, for example, an electric hygrometer.

The flow meter 117 is a sensor that measures the flow rate of air flowing into the sensing area S from the external space due to the operation of the fan 114, and outputs a flow rate signal indicating the measured flow rate to the control unit 118.

The flowmeter 117 is, for example, a thermal flowmeter that follows the temperature difference measurement method, and a thermometer 1171 (temperature measurement means, an example of a second thermometer) that measures the temperature of air flowing from the outside to the inside of the smoke sensor 11. have The thermal flow meter has a heater and two temperature sensors arranged upstream and downstream of the air flow with respect to the heater. In this case, the upstream temperature sensor serves as the thermometer 1171 . Thermometer 1171 outputs a temperature signal indicating the measured temperature to control unit 118 . The thermometer 1171 is arranged upstream of the air flow path from the thermometer 1121 .

The control unit 118 is a device that controls the operation of the smoke sensor 11, etc. The hardware of the control unit 118 is, for example, a computer, and the control unit 118 is realized by the computer performing processing according to the program for the control unit 118 .

FIG. 3 is a diagram showing the configuration of the computer 10 employed as hardware for the control unit 118. As shown in FIG. The computer 10 includes a processor 101 that performs various data processing, a memory 102 that stores various data, an input/output interface 103 that exchanges signals with components such as the light emitting unit 111 included in the smoke sensor 11, and an external device. (In this case, the host system 12) is provided with a communication interface 104 for transmitting and receiving data.

FIG. 4 is a diagram showing the functional configuration of the control unit 118. As shown in FIG. That is, the computer 10 performs processing according to the program for the control unit 118, thereby realizing the control unit 118 having the components shown in FIG. The functional components included in the control unit 118 will be described below.

Storage means 1180 stores various data. The data stored by the storage means 1180 includes the following.
(1) Smoke detection condition data indicating conditions for determining the presence or absence of smoke based on the light intensity signal output from the light receiving unit 112 (2) Smoke sensor 11 based on the flow signal output from the flow meter 117 Flow rate abnormality judgment condition data indicating the conditions for judging whether there is an abnormality in the flow rate of air flowing from the outside to the inside (3) Air temperature, air relative humidity, and temperature of the object where condensation occurs Dew point temperature data showing the correspondence with the upper limit (dew point temperature) of

The smoke detection condition data in (1) above indicates, for example, the light intensity range and duration threshold. That is, when the light intensity indicated by the light intensity signal output by the light receiving unit 112 is maintained within the light intensity range indicated by the smoke detection condition data for a period of time equal to or longer than the threshold, the air around the smoke sensor 11 emits smoke. is determined to exist.

The above (2) flow rate abnormality determination condition data indicates, for example, the air flow rate range and duration threshold. That is, when the flow rate of air indicated by the flow rate signal output by the flow meter 117 is maintained outside the range of the flow rate indicated by the flow rate abnormality determination condition data for a period of time equal to or greater than the threshold value, the air flows into the inside from the outside of the smoke sensor 11. It is determined that the air flow rate is abnormal.

The dew point temperature data in (3) above is, for example, data in the tabular form shown in FIG. The rows of the table shown in FIG. 5 correspond to the temperature of the air surrounding the object. The columns of the table shown in FIG. 5 correspond to the relative humidity of the air around the object on which condensation occurs. The numerical value stored in each cell of the table shown in FIG. 5 indicates the dew point temperature, that is, the temperature of the object at which condensation begins to form on the object. For example, 0.1 degrees Celsius stored in the cell in the row of 10 degrees Celsius and the column of 50% relative humidity in FIG. If there is an object with a temperature of , it means that condensation will form on that object.

The description of the functional configuration of the control unit 118 will be continued with reference to FIG. The light emission instructing means 1181 instructs the light emitting section 111 to emit light. The light intensity signal acquisition means 1182 acquires the light intensity signal output from the light receiving section 112 .

A temperature signal acquisition means 1183 acquires a temperature signal output from the thermometer 1121 . Humidity signal acquisition means 1184 acquires the humidity signal output from hygrometer 116 .

The flow rate signal acquisition means 1185 acquires the flow rate signal output from the flow meter 117 . A temperature signal acquisition means 1186 acquires a temperature signal output from the thermometer 1171 .

The smoke determination means 1187 determines whether or not the light intensity indicated by the light intensity signal acquired by the light intensity signal acquisition means 1182 satisfies the conditions indicated by the smoke detection condition data. Determine if there is smoke in the air. When the smoke determining means 1187 determines that smoke exists, it generates smoke generation notification data for notifying the generation of smoke. The smoke occurrence notification data generated by the smoke determination means 1187 is transmitted to the host system 12 by the communication means 1190 .

The dew condensation estimation means 1188 calculates the temperature indicated by the temperature signal obtained by the temperature signal obtaining means 1183 from the thermometer 1121 of the light receiving unit 112, the relative humidity indicated by the humidity signal obtained by the humidity signal obtaining means 1184 from the hygrometer 116, and the temperature Based on the temperature indicated by the temperature signal obtained by the signal obtaining means 1186 from the thermometer 1171 of the flow meter 117 and the relationship between the relative humidity indicated by the dew point temperature data (FIG. 5) and the two types of temperature, dew condensation is detected on the lens 113. Estimate whether or not it has occurred.

The dew condensation estimation means 1188 regards the current temperature indicated by the temperature signal acquired by the temperature signal acquisition means 1183 from the thermometer 1121 of the light receiving unit 112 as the current temperature of the lens 113 . That is, in this embodiment, the lens 113 is in contact with the photodiode of the light receiving unit 112, and the temperature difference between the photodiode and the lens 113 is negligibly small.

Also, the dew condensation estimation means 1188 regards the temperature indicated by the temperature signal acquired by the temperature signal acquisition means 1186 from the thermometer 1171 of the flow meter 117 as the current temperature of the air around the lens 113 . That is, in this embodiment, the time required for the air flowing from the outside to the inside of the smoke sensor 11 to move from the position of the flow meter 117 to the position of the lens 113 is negligible compared to the time required for the occurrence and elimination of condensation. be small.

Of the table indicated by the dew point temperature data ( FIG. 5 ), the row corresponding to the temperature indicated by the temperature signal obtained by the temperature signal obtaining means 1186 from the thermometer 1171 of the flow meter 117 and the humidity signal obtaining means 1184 from the hygrometer 116 The dew point temperature indicated by the numerical value stored in the cell where the columns corresponding to the relative humidity indicated by the obtained humidity signal intersect is defined as the dew point temperature R, and the temperature signal obtained by the temperature signal obtaining means 1183 from the thermometer 1121 of the light receiving unit 112 is Assuming that the indicated current temperature is the lens temperature T, the dew condensation estimation means 1188 estimates as follows.

If the lens temperature T is equal to or lower than the dew point temperature R, it is assumed that condensation has occurred on the lens 113 .
If the lens temperature T is higher than the dew point temperature R, it is assumed that no dew condensation has occurred on the lens 113 .

When the dew condensation estimation means 1188 estimates that dew condensation has occurred on the lens 113, it generates dew condensation occurrence notification data for notifying the occurrence of dew condensation. The dew condensation occurrence notification data generated by the dew condensation estimation means 1188 is transmitted to the host system 12 by the communication means 1190 .

The flow rate abnormality determination means 1189 determines whether or not the air flow rate indicated by the flow rate signal acquired by the flow rate signal acquisition means 1185 satisfies the condition indicated by the flow rate abnormality determination condition data. It is determined whether or not the flow rate of the air flowing inside is abnormal.

When the flow rate abnormality determination means 1189 estimates that the flow rate of the air flowing from the outside to the inside of the smoke sensor 11 is abnormal, it generates flow rate abnormality notification data for notifying the flow rate abnormality. The flow rate abnormality notification data generated by the flow rate abnormality determination means 1189 is transmitted to the host system 12 by the communication means 1190 .

A communication means 1190 transmits and receives various data to and from the host system 12 . Specifically, as described above, the communication means 1190 uses the smoke occurrence notification data generated by the smoke determination means 1187, the condensation occurrence notification data generated by the condensation estimation means 1188, and the condensation occurrence notification data generated by the flow rate abnormality determination means 1189. The abnormal flow rate notification data is sent to the host system 12 .

According to the smoke detection system 1 described above, it is possible to know whether condensation has occurred on the lens 113 of the smoke sensor 11 . Therefore, the host system 12 or the user of the host system 12 notifies the occurrence of condensation by sending the condensation occurrence notification data when the smoke detector 11 notifies the occurrence of smoke by sending the smoke occurrence notification data. If so, the situation can be dealt with considering the possibility that the smoke outbreak notification is a false alarm.

[Modification]
The above-described embodiment is a specific example of the present invention, and various modifications are possible within the scope of the technical idea of the present invention. Examples of these modifications are shown below. Note that two or more modified examples shown below may be appropriately combined.

(1) In the embodiments described above, the hygrometer 116 measures relative humidity. Alternatively, hygrometer 116 may measure absolute humidity. Relative humidity is calculated according to a known predetermined formula from absolute humidity and temperature. Therefore, for example, the dew condensation estimation means 1188 calculates the relative humidity based on the absolute humidity measured by the hygrometer 116 and the temperature measured by the thermometer 1171, and estimates the presence or absence of condensation on the lens 113. good too.

(2) In the above-described embodiment, the dew condensation estimator 1188 detects dew condensation based on the measured value of the thermometer 1121 and the measured value of the thermometer 1171 arranged upstream of the thermometer 1121 in the air flow path. Presence or absence of The two temperatures used by the dew condensation estimating means 1188 to estimate the presence or absence of dew condensation may not be temperatures measured by different temperature measuring means located upstream and downstream of the air flow path.

FIG. 6 is a diagram schematically showing the configuration of the smoke sensor 11 according to this modification. The smoke sensor 11 according to this modification differs from the smoke sensor 11 according to the above-described embodiment in that it includes a thermometer 119 .

The thermometer 119 is arranged within the sensing area S and measures the temperature of the air within the sensing area S. The position of the thermometer 119 does not necessarily have to be on the upstream side of the air flow path as compared with the thermometer 1121 of the light receiving section 112 .

FIG. 7 is a diagram showing the functional configuration of the control unit 118 according to this modification. The control unit 118 according to this modification differs from the control unit 118 according to the above-described embodiment in that the temperature signal acquiring means 1186 acquires the temperature signal from the thermometer 119 instead of the thermometer 1171 .

In this modification, the dew condensation estimating means 1188 uses the temperature measured by the thermometer 119 instead of the temperature measured by the thermometer 1171 to estimate the presence or absence of dew condensation.

Further, in the smoke sensor 11 having the configuration shown in FIG. The presence or absence of dew condensation may be determined using the time-dependent change in temperature indicated by the measured value measured by 119 .

FIG. 8 is a diagram showing the functional configuration of the control unit 118 according to such a modification. A control unit 118 according to this modification includes a clock means 1191 . The timer 1191 continuously measures the current time based on, for example, a clock signal generated by a clock included in the processor 101 .

Each time the temperature signal acquisition means 1186 acquires a temperature signal from the thermometer 119, the storage means 1180 stores data indicating the temperature indicated by the temperature signal in association with the current time measured by the clock means 1191 as temperature log data. remember as The temperature log data indicates changes in the temperature of the air within the sensing area S as measured by the thermometer 119 over time.

The temperature of the lens 113 follows changes in the temperature of the air around the lens 113 at a response speed calculated according to a known formula based on the heat capacity of the lens 113 . Therefore, in this modification, dew condensation estimation means 1188 calculates the temperature of lens 113 based on the temperature log data, and uses the calculated temperature of lens 113 to estimate the presence or absence of condensation on lens 113 .

Note that in this modification, the temperature measured by the thermometer 1171 of the flow meter 117 may be used instead of the temperature measured by the thermometer 119 .

Also, the thermometer 119 may be configured integrally with the hygrometer 116 .

(3) In the above-described embodiment, the dew condensation estimating means 1188 estimates the presence or absence of dew condensation based on the measured value of the thermometer 1121 and the measured value of the thermometer 1171 . Alternatively, the dew condensation estimating means 1188 may estimate the presence or absence of dew condensation based on the measured value of the thermometer 1121 and the measured value of the thermometer included in the computer 10 constituting the control unit 118 .

FIG. 9 is a diagram showing the configuration of the computer 10 according to this modification. In this variant, the computer 10 is equipped with a thermometer 105 for measuring the ambient temperature.

After the computer 10 starts operating, the temperature measured by the thermometer 105 rises until a predetermined length of time elapses. indicates the temperature determined by the temperature of Since the processing load of the computer 10 does not fluctuate greatly, the amount of heat generated by the computer 10 can be considered constant. Also, the temperature of the air around the computer 10 and the temperature of the air flowing into the sensing area S from the external space are the same, or there is a certain relationship between those temperatures.

Therefore, there is a certain relationship between the measured value of the thermometer 105 and the temperature of the air flowing into the sensing area S from the external space after a predetermined length of time has elapsed since the computer 10 started operating. Therefore, in this modification, a calculation formula or a correspondence table for estimating the temperature of the air flowing into the sensing region S from the external space is stored in advance in the storage means 1180 from the measured value of the thermometer 105. .

In this modification, temperature signal acquisition means 1186 acquires the temperature signal output from thermometer 105 . The dew condensation estimating means 1188 uses the temperature indicated by the temperature signal acquired from the thermometer 105 by the temperature signal acquiring means 1186, according to the calculation formula or the correspondence table stored in the storage means 1180, and flows into the sensing region S from the external space. Estimate air temperature. Then, dew condensation estimation means 1188 estimates the presence or absence of dew condensation based on the temperature estimated from the measured value of thermometer 105 and the measured value of thermometer 1121 .

Further, when the thermometer 1171 (or the thermometer 119 in the modified example (2) described above) is operating normally, the dew condensation is estimated using the measurement value of the thermometer, and the thermometer 1171 (or If the thermometer 119 in the above modification (2) fails, the dew condensation may be estimated using the measured value of the thermometer 105 instead of the measured value of the thermometer.

(4) The smoke sensor 11 has, as a light emitting means, a second light emitting part for sensing contamination in the sensing area S separately from the light emitting part 111 (first light emitting part), and dew condensation estimating means 1188. However, in addition to the measured values of the thermometers 1121 and 1171 and the measured value of the hygrometer 116, the presence or absence of dew condensation is estimated based on the measured value of the light receiving unit 112 when the second light emitting unit is emitting light. may be performed.

FIG. 10 is a diagram schematically showing the configuration of the smoke sensor 11 according to this modification. The smoke sensor 11 according to this modified example differs from the smoke sensor 11 according to the above-described embodiment in that it includes a light emitting section 120 (an example of a second light emitting section).

The light-emitting part 120 is a light-emitting part for sensing dirt on the lens 113, and is arranged at a position closer to the lens 113 than the light-emitting part 111, away from the air flow path in the sensing area S, for example. Therefore, the intensity of the light emitted from the light emitting unit 120 and received by the light receiving unit 112 is substantially unaffected by particles in the air flowing from the air inlet P toward the exhaust port Q, and is mainly affected by the lens 113. Varies depending on degree of contamination.

FIG. 11 is a diagram showing the functional configuration of the control unit 118 according to this modification. Compared to the control unit 118 according to the above-described embodiment, the control unit 118 according to this modification has a light emission instructing means 1192 for instructing the light emitting unit 120 to emit light, and a light receiving unit 1192 for instructing the light emitting unit 120 to emit light. 112 is provided with contamination estimation means 1193 for estimating the degree of contamination of the lens 113 based on the light intensity signal output by 112 .

In this modified example, storage means 1180 stores data indicating the correspondence relationship between the light intensity indicated by the light intensity signal output from light receiving portion 112 when light emitting portion 120 is emitting light and the degree of dirt on lens 113. The dirt estimation means 1193 uses this data to estimate the degree of dirt on the lens 113 .

The smoke determining means 1187 determines the light intensity indicated by the light intensity signal output by the light receiving section 112 when the light emitting section 111 is emitting light, or the smoke level, according to the degree of dirt on the lens 113 estimated by the dirt estimating section 1193 . The presence or absence of smoke is determined by correcting the light intensity range indicated by the sensing condition data.

When dew condensation estimation means 1188 estimates that dew condensation is occurring based on the temperature measured by thermometers 1121 and 1171 and the humidity measured by hygrometer 116 in light of the dew point temperature data (FIG. 5). , causes the light emission instruction means 1192 to instruct the light emission section 120 to emit light. The dew condensation estimating means 1188 determines the light intensity indicated by the light intensity signal output from the light receiving part 112 when the light emitting part 120 emits light according to the instruction and is acquired by the light intensity signal acquiring means 1182 to determine whether condensation has occurred. Compare with the light intensity under normal conditions.

The dew condensation estimating means 1188 determines that dew condensation has occurred only when the light intensity indicated by the light intensity signal output from the light receiving unit 112 while the light emitting unit 120 is emitting light is different from the normal light intensity by a threshold value or more. determine and generate dew condensation estimation data.

According to this variant, for example, the measurements of thermometer 1121, thermometer 1171, or hygrometer 116 contain errors, and those measurements indicate the occurrence of condensation in light of the dew point temperature data, but in reality prevents erroneous notification of the occurrence of dew condensation when no dew condensation has occurred.

(5) In the embodiment described above, the temperature of the lens 113 is measured by the thermometer 1121 provided in the light receiving section 112 . Alternatively, the temperature of lens 113 may be measured by a thermometer different from thermometer 1121 . According to this modification, even if the temperature of the lens 113 cannot be accurately measured by the thermometer 1121 provided in the light receiving unit 112 because the light receiving unit 112 and the lens 113 are separated from each other, the dew condensation estimating means 1188 Presence or absence of condensation can be estimated.

(6) When dew condensation occurs, erroneous detection of smoke is more likely to occur than when dew condensation does not occur. Therefore, when the dew condensation estimating means 1188 estimates that condensation is occurring, the smoke determining means 1187 determines the presence or absence of smoke under stricter conditions than normal (when it is estimated that no condensation is occurring). may be determined.

In this modification, for example, the storage means 1180 stores smoke sensing condition data for normal use and for dew condensation. As described above, the smoke detection condition data indicates, for example, the light intensity range and duration threshold as conditions for determining the presence or absence of smoke. The light intensity range indicated by the smoke sensing condition data for when condensation occurs is narrower than the light intensity range indicated by the smoke sensing condition data for normal times. Also, the duration indicated by the smoke sensing condition data for when condensation occurs is longer than the duration indicated by the smoke sensing condition data for normal times.

While the dew condensation estimation means 1188 estimates that no condensation has occurred, the smoke determination means 1187 determines the presence or absence of smoke using the normal smoke detection condition data. On the other hand, while the condensation estimating means 1188 is estimating that condensation is occurring, the smoke determining means 1187 determines the presence or absence of smoke using the smoke detection condition data for when condensation is occurring.

According to this modification, the presence or absence of smoke is determined under stricter conditions while it is estimated that condensation is occurring, so false alarms of smoke caused by condensation are reduced.

(7) In the above-described embodiment, the presence or absence of dew condensation on the lens 113 is estimated. The lens 113 is an example of an object for which the smoke sensor 11 estimates the presence or absence of condensation. may be For example, if the smoke sensor 11 has a lens for directing the light emitted by the light emitting unit 111 to a predetermined range, the presence or absence of dew condensation on the lens may be estimated. Further, the presence or absence of dew condensation on the wall 1101 forming the sensing area S may be estimated.

(8) In the above-described embodiment, the dew condensation estimating means 1188 uses dew point temperature data (FIG. 5) to estimate the presence or absence of dew condensation. Alternatively, the dew condensation estimating means 1188 calculates the dew point temperature according to the dew point temperature calculation formula using the temperature of the air around the object and the relative humidity of the air as variables, and the calculated dew point temperature is measured by the thermometer 1121. The presence or absence of dew condensation may be estimated by comparing with the measured value of .

(9) In the above-described embodiment, the hardware of the control unit 118 is a computer, but the control unit 118 may be configured as a dedicated device having an integrated circuit such as ASIC or FPGA.

DESCRIPTION OF SYMBOLS 1... Smoke detection system, 10... Computer, 11... Smoke sensor, 12... Host system, 101... Processor, 102... Memory, 103... Input/output interface, 104... Communication interface, 105... Thermometer, 110... Case, DESCRIPTION OF SYMBOLS 111... Light-emitting part 112... Light-receiving part 113... Lens 114... Fan 115... Filter 116... Hygrometer 117... Flow meter 118... Control unit 119... Thermometer 120... Light-emitting part 1101... Wall Body 1102 Tube 1103 Tube 1121 Thermometer 1171 Thermometer 1180 Storage means 1181 Light emission instruction means 1182 Light intensity signal acquisition means 1183 Temperature signal acquisition means 1184 Humidity signal Acquisition means 1185 Flow rate signal acquisition means 1186 Temperature signal acquisition means 1187 Smoke determination means 1188 Dew condensation estimation means 1189 Flow rate abnormality determination means 1190 Communication means 1191 Timing means 1192 Light emission instruction Means 1193... Dirt estimation means.

Claims (4)

A smoke sensor that senses the generation of smoke in the external space by sensing particles contained in air flowing into the sensing area from the external space,
a light emitting means for emitting light;
a light receiving means for receiving light;
a temperature measuring means for measuring temperature;
Humidity measuring means for measuring humidity;
A smoke sensor comprising dew condensation estimating means for estimating the presence or absence of dew condensation within the sensing area based on the measured value of the temperature measuring means and the measured value of the humidity measuring means. The temperature measuring means has a first thermometer and a second thermometer arranged upstream of the air flow path from the first thermometer,
2. The dew condensation estimating means estimates the presence or absence of the dew condensation based on the measured value of the first thermometer, the measured value of the second thermometer, and the measured value of the humidity measuring means. The smoke detector described in . 2. The smoke sensor according to claim 1, wherein said dew condensation estimating means estimates the presence or absence of said dew condensation on the basis of changes over time in temperature indicated by the measured values measured by said temperature measuring means and the measured values of said humidity measuring means. vessel. The light emitting means has a first light emitting portion for sensing smoke and a second light emitting portion for sensing dirt within the sensing area,
The dew condensation estimating means estimates the degree of dew condensation based on the measured value of the light receiving means, the measured value of the temperature measuring means, and the measured value of the humidity measuring means when the second light emitting section emits light. The smoke sensor according to any one of claims 1 to 3, wherein the presence or absence is estimated.

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