Flame detector and fire warning equipment

Abstract

To provide a novel configuration to suppress the effect of radio wave noise on a flame detector.SOLUTION: The flame detector comprises a radio wave noise detector that enters a noise receiving state when it detects noise of a prescribed energy or above, thereby preventing fire alarm errors.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a flame detector that detects a fire flame and a fire alarm system having a flame detector. [Background technology]

[0002] Flame detectors use pyroelectric elements to detect infrared light emitted by flames. When a flame detector detects a flame, a detection signal is sent to a fire receiver, which issues a fire alarm. Flame detectors detect the infrared light of flames, so they can detect fires well even when they are far away, and so they can be installed in high ceilings in atriums, gymnasiums, stadiums, etc.

[0003] In recent years, mobile communication systems such as 5G (fifth generation mobile communication system) that wirelessly connect to smartphones and the like have begun to use high frequency bands that are vulnerable to obstacles, and base stations have begun to be installed indoors. Radio waves from the base station become radio noise for flame detectors. Patent Document 1 describes a flame detector equipped with a shielding case that blocks radio noise. The shielding case suppresses the effects of radio noise on the flame detector. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-173490 A Summary of the Invention [Problem to be solved by the invention]

[0005] When a base station for a mobile communication system is installed near a flame detector installed on a high ceiling, the strong radio waves from the base station cause noise to the flame detector. An object of the present invention is to provide a new technology for suppressing the effects of radio wave noise on the flame detector. [Means for solving the problem]

[0006] The flame detector according to one embodiment of the present invention is equipped with a noise radio wave detector, and when the noise radio wave detector detects radio waves of a predetermined energy or more, it enters a noise reception state, and measures to prevent false fire alarms are taken due to the noise reception state. In addition, a fire alarm system according to one embodiment of the present invention comprises a flame detector and a fire receiver connected to the flame detector, the flame detector having a noise radio wave detector and transmitting a noise signal indicating the amount of radio wave energy detected by the noise radio wave detector, and the fire receiver receiving the noise signal and taking measures to prevent false fire alarms when the noise radio wave detector is in a noise reception state in which it has detected radio waves of a predetermined energy or more. Effect of the Invention

[0007] It is possible to prevent false fire detection caused by noise radio waves. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a situation in which a base station of a mobile communication system is installed near a flame detector. [Diagram 2] FIG. 1 is a diagram showing a fire alarm system including a flame detector according to a first embodiment of the present invention. [Diagram 3] Flow of radio wave monitoring by the control unit. [Figure 4] Control flow of fire monitoring by the control unit. [Diagram 5] FIG. 11 is a diagram showing a fire alarm system according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Figure 1 shows a situation where a base station for a mobile communication system is installed near a flame detector. In Figure 1, conventional flame detectors 8 are installed on the ceiling C of an indoor sports stadium and in several places near the ceiling C. When the flame detectors 8 detect a fire, they send a fire detection signal to a fire receiver 9, which then issues an alarm or other warning. In a large space such as an indoor sports stadium, smoke generated when a fire breaks out takes time to reach the ceiling. On the other hand, flame detectors can detect fires from far away as long as the area has good visibility, making them suitable for detecting fires in such spaces.

[0010] A base station 4 of a mobile communication system may be installed in such a location. Like the flame detector 8, the base station 4 is likely to be installed in a location with good visibility. This may result in the base station 4 being close to the flame detector 8. The flame detector 8 installed close to the base station 4 will receive strong radio waves. This may result in the strong radio waves becoming radio noise, causing the flame detector 8 to make a false detection, sending a flame detection signal to the fire receiver 2 and causing a fire alarm. The flame detector 8 detects infrared light from a fire with an internal flame detector (not shown), and since the infrared light entrance portion cannot be covered, it is difficult to shield the entire detector with a conductor. EXAMPLES

[0011] Therefore, a noise radio wave detector is provided in the flame detector, and when the noise radio wave detector detects radio waves of a predetermined energy or more, the noise radio wave detector is set to a noise receiving state. In the noise receiving state, measures are taken to prevent false fire alarms.

[0012] FIG. 2 shows a fire alarm system including the flame detector 1 of the first embodiment. The flame detector 1 is provided with a flame detector 11 and a noise radio wave detector 13 on a circuit board 14 in a housing 18. The flame detector 11 and the noise radio wave detector 13 of the first embodiment are both pyroelectric sensors. The flame detector 11 is provided with a light entrance window 12 facing downward in FIG. 2, and infrared light generated by a fire enters the flame detector 11 through the light entrance window 12. On the other hand, the noise radio wave detector 13, which is a pyroelectric sensor, is designed not to allow infrared light to enter from the outside. Therefore, the noise radio wave detector 13 functions as a sensor for radio wave noise. Furthermore, the flame detector 1 is provided with a control unit 15, a memory unit 16, and a communication unit 17 on the circuit board 14. The communication unit 17 of the flame detector 1 is connected to the fire receiver 2 via the sensing line 3.

[0013] When a fire occurs, the flame detector 11 detects infrared light due to the fire through the light entrance window 12 and sends a detection signal to the control unit 15. The control unit 15 judges whether there is a fire using a program stored in the memory unit 16, and if it judges there is a fire, it sends a detection transmission instruction to the communication unit 17 to transmit a fire detection signal. The communication unit 17 that receives the detection transmission instruction transmits the fire detection signal to the detection line 3, and the fire receiver 2 receives the fire detection signal and issues a fire alarm.

[0014] The noise radio wave detector 13 is a pyroelectric sensor similar to the flame detector 11, but because no external light enters it, it does not output a signal due to external infrared light. However, the noise radio wave detector 13 sends a signal just like the flame detector 11 when it receives radio waves of a predetermined energy or more that would cause the flame detector 11 to send a signal. Therefore, it functions as a noise radio wave detector. The noise detection signal from the noise radio wave detector 13 is sent to the control unit 15. As a measure to prevent false fire alarms, the control unit 15 delays the fire judgment in a noise reception state in which the noise detection signal continues for a predetermined period of time. Delaying the fire judgment is a type of false fire alarm prevention measure, and a false fire alarm prevention measure is taken due to the noise reception state.

[0015] 3 and 4, the flow in which the noise radio wave detector 13 detects noise radio waves and the control unit 15 delays the fire determination will be described. FIG. 3 shows the flow of radio wave monitoring by the control unit 15. When the noise radio wave detector 13, which is a pyroelectric sensor, detects radio waves with a predetermined energy or more, a pyroelectric effect occurs and a noise detection signal is sent out. The control unit 15 judges whether there is a noise detection signal (step S11), and if there is a noise detection signal (YES), it sets the radio wave flag stored in the memory unit 16 to 1 (step S12). On the other hand, if there is no noise detection signal (NO), it sets the radio wave flag to 0 (step S13). After steps S12 and S13, the process returns to step S11. The control unit 15 always resets the radio wave flag depending on whether there is a noise detection signal or not.

[0016] 4 is a control flow of fire monitoring by the control unit 15. The control unit 15 receives a detection signal from the flame detector 11, which is a pyroelectric sensor, and judges whether the flame detection condition is met (step S21). If the flame detection condition is not met (NO), step S21 is performed again, and is repeated until the flame detection condition is met. On the other hand, if the flame detection condition is met (YES), it is determined whether the radio wave flag is 1 (step S22). If the radio wave flag is not 1 (NO), it is determined that a fire has occurred (step S23). Then, the control unit 15 sends a detection transmission instruction to the communication unit 17, and the communication unit 17 transmits a fire detection signal to the fire receiver 2. Having received the fire detection signal, the fire receiver 2 issues a fire alarm to notify of a fire.

[0017] On the other hand, when it is determined that the radio wave flag is 1 (YES) in step S22, the control unit 15 delays the fire determination. Specifically, the control unit 15 determines whether the radio wave flag is 1 for 60 seconds after the result of step S22 becomes YES (step S24). If the radio wave flag is no longer 1 before the 60 seconds have elapsed (NO), it is determined that there is a fire in step S23, and a detection and transmission instruction is issued to the communication unit 17. On the other hand, if the radio wave flag is 1 for 60 seconds after the result of step S22 becomes YES (YES), it is determined that there is a noise reception state, and that there is a possibility of a fire (step S25). Then, together with the detection and transmission instruction, a noise signal transmission instruction is issued to the communication unit 17 (step S25). The communication unit 17 transmits a fire detection signal to the fire receiver 2 and also transmits a radio noise signal. By receiving the radio noise signal together with the fire detection signal, the fire receiver 2 issues a fire alarm different from a normal fire alarm, and issues an alert so that the possibility of a false alarm due to radio noise can be recognized.

[0018] 4, a delay can be used to prevent erroneous detection of a fire by determining that a fire has been detected based on a continuous flame detection signal over a certain period of time from the flame detector 11. In this case, when the flame detection condition is satisfied in step S21 including the delay, if the radio flag is 1 in step S22, the fire determination is further delayed in step S24 as a measure to prevent erroneous fire alarms.

[0019] <Variation 1> In the first embodiment, the radio wave flag is stored in the storage unit 16 of the flame detector 1, and the control unit 15 delays the fire judgment in step S24 depending on the state of the radio wave flag. However, in a fire alarm system in which the flame detector transmits a light receiving signal to the fire receiver and the fire receiver judges the fire, the fire receiver delays the fire judgment. In that case, as a measure to prevent false fire alarms, the flame detector transmits a noise receiving signal to the fire receiver via the sensing line when it detects radio waves of a predetermined energy or more, and the fire receiver that receives the noise receiving signal sets the radio wave flag to 1. Then, if the fire receiver continuously detects a flame by the light receiving signal for 60 seconds and the radio wave flag has been 1 continuously for 60 seconds from the start of the flame detection, a fire alarm different from a normal fire alarm is issued as a noise receiving state, and a notice is issued so that the possibility of a false alarm due to radio wave noise can be recognized. The transmission of the noise receiving signal is a kind of measure to prevent false fire alarms. In the first modification, not only the radio wave noise situation is used in the event of a fire, but also the fire receiver can monitor the quality of the radio wave environment in a normal monitoring state.

[0020] In the first embodiment and the first modified example, the fire determination is delayed in the noise reception state. The predetermined time until the possible fire state is determined to be 60 seconds as shown in step S24 of FIG. 4 is not limited to this. The possible fire state may be determined to be a possible fire state without waiting for the predetermined time to continue when radio waves are detected, or conversely, the possible fire state may be determined to be a possible fire state after a predetermined time longer than 60 seconds has continued. However, since a fire will spread if an alarm is issued too late, it is preferable that the predetermined time for the possible fire state to continue is 40 seconds or more and 80 seconds or less. EXAMPLES

[0021] The second embodiment is a fire alarm system in which a fire judgment and delay control are performed by a fire receiver, as in the first modification. FIG. 5 shows the fire alarm system of the second embodiment. The flame detector 5 is provided with a flame detector 51 and a noise radio wave detector 53 on a circuit board 54 in a housing 58. The flame detector 51 in the second embodiment is a pyroelectric sensor, but the noise radio wave detector 53 is not a pyroelectric sensor but is provided with a sensor for detecting noise radio waves. The flame detector 51 is provided with a light entrance window 52 facing downward in FIG. 5, and infrared light generated by a fire enters the flame detector 51 through the light entrance window 52. Furthermore, the flame detector 5 is provided with a control unit 55, a memory unit 56, and a communication unit 57 on a circuit board 54. The communication unit 57 of the flame detector 5 is connected to the fire receiver 6 via the sensing line 3. Moreover, the noise radio wave detector 53 has a transmission circuit and transmits a noise reception signal to the fire receiver 6 via the transmission line 7. The transmission of the noise reception signal is a kind of fire false alarm prevention measure.

[0022] When a fire occurs, the flame detector 51 detects infrared light due to the fire through the light entrance window 52 and sends a detection signal to the control unit 55. The control unit 55 judges whether there is a fire using a program stored in the memory unit 56, and if it judges there is a fire, it sends a detection transmission instruction to the communication unit 57 to transmit a fire detection signal. The communication unit 57 that has received the detection transmission instruction transmits the fire detection signal to the detection line 3, and the fire receiver 2 receives the fire detection signal and issues a fire alarm.

[0023] On the other hand, as a measure to prevent false fire alarms, the noise radio wave detector 53 of the flame detector 5 transmits a noise reception signal to the fire receiver 6 via the transmission line 7 when it detects radio waves of a predetermined energy or more. Then, the fire receiver 6 that receives the noise reception signal stores a radio wave flag as in the flame detector 1 of the first embodiment. If the fire receiver 6 continuously obtains a noise reception signal for 60 seconds, it judges that a noise reception state exists and issues a fire alarm different from a normal fire alarm, so that the possibility of a false alarm due to radio wave noise can be recognized. In the second embodiment, as in the first modification, not only is the radio wave noise situation used in the event of a fire, but it is also possible to monitor the quality of the radio wave environment in a normal monitoring state.

[0024] In the first modification and the second embodiment, as a measure to prevent false fire alarms, the flame detector transmits a noise reception signal to the fire receiver when it detects radio waves of a predetermined energy or more. This noise reception signal is a signal that takes two values, indicating whether or not noise is being received. However, the flame detector may transmit a noise signal indicating the amount of radio wave energy detected by the noise receiver. In this case, when the fire receiver receives the noise signal and determines from the noise signal that the noise radio wave detector of the flame detector has continuously detected radio waves of a predetermined energy or more for a predetermined period of time, it determines that the noise is being received and takes measures to prevent false fire alarms.

[0025] In the first embodiment and the like, if the radio wave flag is 1 continuously for 60 seconds in steps S22 and S24 after the flame detection condition is satisfied in step S21 as shown in Fig. 4, a possible fire state is determined in step S25. In a device that determines that a fire has been detected when a flame is continuously detected for a delay time as a flame detection condition, a possible fire state may be determined if the radio wave flag is 1 for a predetermined time period including the delay time.

[0026] In the first and second embodiments and the first modified embodiment, a pyroelectric sensor is used as the flame detector. However, other sensors that detect infrared light, etc. may be used. The flame detector may also be a sensor that detects ultraviolet light, etc. in addition to infrared light.

[0027] Although the examples of the present invention have been described in detail above, the specific configuration is not limited to these embodiments, and the present invention includes design changes within the scope of the present invention. The above-mentioned examples can be combined by utilizing each other's technologies as long as there are no particular contradictions or problems in the purpose and configuration. [Explanation of symbols]

[0028] 1 flame sensor, 11 flame detector, 12 light entrance window, 13 noise radio wave detector, 14 circuit board, 15 control unit, 16 memory unit, 17 communication unit, 18 housing, 2 fire receiver, 3 sensing line, 4 base station, 5 flame detector, 51 flame detector, 52 light entrance window, 53 noise radio wave detector, 54 circuit board, 55 control unit, 56 memory unit, 57 communication unit, 58 housing, 6 fire receiver, 7 transmission line, 8 flame detector, 9 fire receiver, C Ceiling

Claims

1. Equipped with a noise radio wave detector, When the noise radio wave detector detects radio waves having a predetermined energy or more, the device enters a noise reception state. Measures to prevent false fire alarms due to the above noise reception state are taken A flame detector characterized by:

2. The noise radio wave detector is a flame detector that does not have a light entrance window.

2. A flame detector as claimed in claim 1.

3. As a measure to prevent false fire alarms, the fire judgement is delayed.

3. A flame detector according to claim 1 or 2.

4. As a measure to prevent false fire alarms, a noise reception signal is transmitted.

3. A flame detector according to claim 1 or 2.

5. A flame detector; A fire receiver to which the flame detector is connected, The flame detector includes: Equipped with a noise radio wave detector, transmitting a noise signal indicative of the amount of radio wave energy detected by the noise radio wave detector; The fire receiver includes: The noise signal is received, and the noise radio wave detector detects radio waves of a predetermined energy or more, indicating that the noise is in a noise receiving state, and measures are taken to prevent false fire alarms. A fire alarm system comprising:

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