Projected beam smoke detector

Abstract

To enable checking of whether a heater is normally operating in a projected beam smoke detector with a heater that prevents a non-fire alarm due to condensation.SOLUTION: A projected beam smoke detector that senses a fire from a reduced amount of light reception caused by blocking of transmitted light with smoke, comprises, in least one of a light transmission unit and a light reception unit: a heating unit that heats an optical member; and temperature detection means for detecting a temperature of the heating unit. A heating abnormality of the heating unit is detected by the temperature detection means.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a photoelectric separation type sensor for detecting fire in a large space, tunnel, or the like.

Background Art

[0002] The photoelectric separation type sensor includes a light emitting unit and a light receiving unit, and senses smoke by receiving the light emitted from the light emitting unit with the light receiving unit. When there is smoke on the optical path, the amount of received light obtained by the light receiving unit decreases, so that smoke can be detected. The photoelectric separation type sensor is provided with an optical system such as a lens or an optical filter in the light emitting unit and the light receiving unit because it uses light.

[0003] When dew condensation occurs in the optical system in the light emitting unit or the light receiving unit, the light cannot reach the light receiving unit, and the amount of received light in the light receiving unit decreases even without smoke. Then, due to the decrease in the amount of received light caused by dew condensation in the optical system, there is a possibility that a non-fire alarm may occur in the photoelectric separation type sensor.

[0004] Therefore, in the photoelectric separation type sensor of Patent Document 1, a heater is provided to indirectly heat optical members such as a lens and the front plate of the cover. By this heating, dew condensation is prevented and non-fire alarms are suppressed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in a photoelectric separation type sensor that prevents dew condensation by heating with a conventional heater, it has been difficult to determine whether heating is actually being performed. For example, there has been no method to confirm whether the heater of the photoelectric separation type sensor is operating properly during inspection. Even if an operator tries to touch the light emitting unit or the light receiving unit by hand to check the temperature during inspection, the heating by the heater is about room temperature + 5°C, making it difficult to confirm. Therefore, when the heater malfunctions, for example, a non-fire alarm due to dew condensation occurs, and it will be determined that the heater is not operating.

[0007] An object of the present invention is to enable confirmation of whether a heater is operating normally in a photoelectric separation type sensor with a heater that prevents non-fire alarms due to dew condensation.

Means for Solving the Problem

[0008] In a photoelectric separation type sensor that detects a fire by a decrease in the amount of received light caused by smoke blocking the emitted light according to an embodiment of the present invention, a heating unit that heats an optical member and temperature detection means that detects the temperature of the heating unit are provided in at least one of a light emitting unit and a light receiving unit, and the temperature detection means detects an abnormal heating of the heating unit.

Effect of the Invention

[0009] According to the present invention, it is possible to confirm whether the heater of the photoelectric separation type sensor is operating normally.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0011] FIG. 1 shows a situation where the photoelectric separation type sensor of the embodiment in the present invention is installed in a building B. In FIG. 1, the building B is an indoor arena, and the photoelectric separation type sensor is installed in the indoor arena. The photoelectric separation type sensor is formed by connecting a light-receiving part 1 and a light-transmitting part 2 with a wiring 3. The light-receiving part 1 and the light-transmitting part 2 are provided at a relatively high position of the building B, and infrared light Ir is transmitted from the light-transmitting part 2 to the light-receiving part 1. Then, when the infrared light Ir emitted from the light-transmitting part 2 is blocked by the smoke of a fire and the light-receiving amount decreases at the light-receiving part 1, it is determined that the light-receiving part 1 has detected the smoke. The light-receiving part 1 that has determined that it has detected the smoke transmits a smoke detection signal to the fire receiver 4 via a wiring 5.

[0012] FIG. 2 shows a connection configuration diagram of the photoelectric separation type sensor in the embodiment. In the photoelectric separation type sensor, the light-receiving part 1 and the light-transmitting part 2 are connected by a wiring 3. Further, the light-receiving part 1 of the photoelectric separation type sensor is connected to the fire receiver 4 by a wiring 5. The light-receiving part 1 is connected to the wirings 3 and 5 with a connection terminal 11, and the light-transmitting part 2 is connected to the wiring 3 with a connection terminal 21. The fire receiver 4 is connected to the wiring 5 with a connection terminal 41.

[0013] The wiring 5 includes a power supply line for supplying power from the fire receiver 4 to the photoelectric separation type sensor and a signal line for sending a smoke detection signal from the photoelectric separation type sensor to the fire receiver 4. The wiring 5 is connected by wiring across a plurality of photoelectric separation type sensors. The wiring 5 shown in FIG. 2 is connected to the light-receiving part in the next photoelectric separation type sensor at the tip indicated by the arrow and is connected by sequential passing wiring.

[0014] The light-receiving unit 1 passes an electric current from the connection terminal 11 to the wiring 3. In the light-transmitting unit 2, the electric current flowing through the wiring 3 enters from the connection terminal 21, and the light-emitting element 22 of the infrared LED emits light to send out infrared light Ir. The light-receiving unit 1 monitors the infrared light Ir that enters the light-receiving element 16 under the control of the CPU 155 provided in the circuit unit 15. Then, under the control of the CPU 155, the light-receiving unit 1 sends out an electric current to the wiring 3 and monitors the infrared light Ir at the sending timing. When the received light amount at the sending timing drops below a predetermined value, the CPU 155 determines that smoke is detected and transmits a smoke detection signal to the fire receiver 4 from the connection terminal 11 via the wiring 5.

[0015] On the other hand, in the light-receiving unit 1, the heater 182 generates heat by the electric power supplied from the heater power supply 6. Then, the temperature is detected by the temperature sensor 183 which is a temperature detection means, and the CPU 155 makes a determination. When making the determination, the CPU temperature obtained by the CPU temperature sensor (not shown) originally mounted on the CPU 155 is used as a comparison reference. When the CPU 155 determines that there is a temperature abnormality, the abnormality lamp 157 blinks to notify the temperature abnormality of the heater 182.

[0016] FIG. 3 is a perspective view of the light-receiving unit 1 in the photoelectric separation type sensor of the embodiment. An abnormality lamp 157 is provided in front of the front cover 17, and the temperature abnormality of the heater 182 can be confirmed from the outside of the light-receiving unit 1. A light transmission window 171 is provided in the upper front part of the front cover 17, and the infrared light Ir passes through the light transmission window 171 and is received by the light-receiving element 16 shown in FIG. 2. Also, cover fixing screws 172 are provided in the lower front part of the front cover 17. The cover fixing screws 172 are used when fixing the front cover 17.

[0017] FIG. 4 shows a side view of the light-receiving unit 1 in the photoelectric separation type sensor of the embodiment with the front cover 17 removed. The right side of FIG. 4 is the front of the light-receiving unit 1. A back plate 12 is provided behind the light-receiving unit 1, and a fixed substrate 13 is fixed to the back plate 12. The fixed substrate 13 is a metal plate (iron plate) bent at two locations in a crank shape when viewed from the side, bent at a right angle forward from the back portion 131 to form a circuit fixing portion 132, and bent at a right angle downward from the circuit fixing portion 132 to form a cover mounting portion 133. The fixed substrate 13 is fixed to the back plate 12 at the back portion 131. And an optical member 14 is fixed to the back portion 131. In FIG. 4, a part of the optical member 14 is hidden by the side portion 181a of the heat sink 181 described later. A circuit portion 15 is fixed downward to the circuit fixing portion 132, and a heating portion 18 is fixed upward to the heat sink fixing screw 184 with a space therebetween.

[0018] The heating portion 18 located above the circuit fixing portion 132 has an L-shaped heat sink 181, a heater 182, a temperature sensor 183, and a heat sink fixing screw 184. The heat sink 181 is a metal plate (iron plate) and has a high thermal conductivity. The heater 182 and the temperature sensor 183 are attached adjacent to the side portion 181a of the heat sink 181. Also, a temperature-sensitive sheet 191 is provided near the heater 182 (on the surface) by being attached thereto, so it is provided near the heating portion 18.

[0019] On the other hand, in the circuit portion 15 located below the circuit fixing portion 132, a circuit portion upper plate 151 is provided above, and a circuit portion cover 153 is provided so as to surround the circuit board 154, the CPU 155, the memory 156, etc. below it. And a temperature-sensitive sheet 192 is attached to the side surface of the circuit portion cover 153. The temperature-sensitive sheet 192 is provided at a location separated from the heater 182 and the heating portion 18.

[0020] FIG. 5 shows a front view of the light-receiving unit 1 in the photoelectric separation type sensor of the embodiment with the front cover 17 removed. The fixed substrate 13 is fixed to the back plate 12 at the back surface portion 131, and the optical member 14 is fixed to the back surface portion 131. The optical member 14 has a lens 141 and the like. Further, the heating unit 18 has an L-shaped heat sink 181, a heater 182, a temperature sensor 183, and heat sink fixing screws 184. The heat sink 181 has a side portion 181a and a lower portion 181b, and the lower portion 181b is fixed to the circuit fixing portion 132 at intervals by four heat sink fixing screws 184. Also, the heater 182 and the temperature sensor 183 are attached adjacent to the side portion 181a of the heat sink 181.

[0021] The fixed substrate 13 is bent downward at a right angle near the center of the circuit fixing portion 132 to form a cover mounting portion 133. A screw hole 133a is provided in the cover mounting portion 133. When attaching the front cover 17 shown in FIG. 3 to the front, the cover fixing screw 172 is screwed into the screw hole 133a.

[0022] In the circuit portion 15, a circuit portion upper plate 151 is provided above, and a circuit board 154 is attached below via connection posts 152. Then, the circuit board 154 and the like are covered by a circuit portion cover 153. The circuit portion upper plate 151, the connection posts 152, and the circuit portion cover 153 are formed of resin. The resin has a lower thermal conductivity compared to the metal heat sink 181. A CPU 155, a memory 156, an abnormality lamp 157, etc. are attached to the circuit board 154.

[0023] The heating unit 18 extends in an L-shape from the side of the optical member 14 downward. The heat generated by the heater 182 is conducted to the heat sink 181, and the optical member 14 is warmed from the side portion 181a and the lower portion 181b to prevent dew condensation on the optical member 14.

[0024] On the other hand, the heat sink 181 is fixed to the circuit fixing part 132 of the fixed substrate 13 by the heat sink fixing screw 184 at the lower part 181b away from the heater 182. Since there is a gap between the heat sink 181 and the circuit fixing part 132 below it, the heat of the heat sink 181 is not easily transmitted to the fixed substrate 13. In the circuit part 15 fixed to the lower part of the circuit fixing part 132, the heat of the heater 182 is hardly transmitted to the CPU 155 mounted on the circuit board 154 connected to the circuit part upper plate 151 by the connecting pole 152. Therefore, in this embodiment, the CPU temperature obtained by the CPU temperature sensor mounted on the CPU 155 is used as a comparison standard for the heating part temperature, and the heating abnormality of the heating part 18 is detected by the temperature difference between the heating part temperature and the CPU temperature. Basically, all CPUs are provided with a CPU temperature sensor for the purpose of controlling the temperature of the CPU, etc., but in this embodiment, this CPU temperature sensor is used to obtain the temperature that is the comparison standard for the heating part temperature.

[0025] Next, a flow for displaying an abnormality based on the heated part temperature detected by temperature sensor 183 will be described with reference to Fig. 6. First, CPU 155 stores the CPU temperature in memory 156 (step S1). CPU 155 is provided with a CPU temperature sensor that detects the internal temperature of CPU 155. CPU 155 calculates the average temperature for a predetermined period of time prior to the temperature detection, and stores this in memory 156 as the CPU temperature. The CPU temperature becomes a comparison standard for the heated part temperature.

[0026] Next, CPU 155 obtains the heating part temperature from temperature sensor 183 provided in heating part 18 and stores it in memory 156 (step S2). Then, it is determined whether the heating part temperature is less than the CPU temperature plus a predetermined value (step S3). If YES, it turns on the abnormality light 157 (step S4) and returns to step S1. On the other hand, if NO, it returns directly to step S1. In this manner, a heating abnormality in heating part 18 is detected based on the temperature difference between the CPU temperature detected by the CPU temperature sensor provided in CPU 155 and the heating part temperature detected by temperature sensor 183. In this embodiment, an abnormality in which heating part 18 is not heating is detected as a heating abnormality.

[0027] The CPU temperature changes according to the usage status of the CPU 155. However, by setting a relatively long predetermined time in step S1 to calculate the average temperature, it can be used as an indicator of the ambient temperature around the light-receiving unit 1. When the ambient temperature is high, the CPU temperature also becomes high, and when the ambient temperature is low, the CPU temperature also becomes low. Since the heater temperature is affected by the ambient temperature, it is possible to prevent misjudgment when comparing with the heater temperature in step S3. And by using the CPU temperature as a comparison reference for the heater temperature, it is possible to prevent misjudgment even when the ambient temperature changes.

[0028] Note that the CPU temperature, which is the average temperature of the CPU, when there is not much temperature rise due to the usage status of the CPU 155, the predetermined value in step S3 is a “+” value. However, when the CPU 155 is likely to generate heat, the predetermined value in step S3 may be a value of “0” or “-”. Also, in a usage situation where the CPU has a high usage such that the temperature rise due to the CPU itself becomes large, the predetermined value may be changed according to the usage status of the CPU, such as by decreasing the predetermined value.

[0029] In the embodiment, the temperature sensor 183 is provided on the heat dissipation plate 181 adjacent to the heater 182, but the temperature sensor 183 may be installed at any location of the heating unit 18. However, since the temperature sensor 183 is used to monitor the operating status of the heater 182, it is desirable to provide it at a position where the temperature by the heater 182 is likely to be reflected, such as a position in contact with the heater 182 or on the opposite side of the heater 182 across the heat dissipation plate 181.

[0030] In the embodiment, as temperature detection means, a thermosensitive sheet 191 that changes color according to temperature is further provided. In the embodiment, the thermosensitive sheet 191 is attached to the heater 182. Also, a thermosensitive sheet 192 is provided on the side surface of the circuit unit 15 and is attached to the circuit unit cover 153. The circuit unit cover 153 is separated from the heater 182, and it is difficult for the heat from the heater 182 to be transmitted. Therefore, it is possible to detect an abnormal heating of the heating unit 18 in the form of a difference in color between the thermosensitive sheets 191 and 192.

[0031] In the photoelectric separation type sensor of the embodiment, during inspection, an operator can recognize the abnormality of the heater 182 from the blinking of the warning lamp 157. When recognizing the abnormality of the heater 182 from the blinking of the warning lamp 157, the operator can remove the front cover 17 by removing the cover fixing screw 172 of the light receiving unit 1, and can visually check the temperature sensitive sheets 191 and 192. Then, since there is no difference in the colors of the temperature sensitive sheets 191 and 192, it is confirmed that the heater 182 is not operating. The light receiving unit 1 where the heater 182 is not operating, the heater power supply 6, etc. will be repaired or replaced.

[0032] In the embodiment, a temperature sensor 183 provided in the heating unit 18 and the like and a temperature sensitive sheet 191 that changes color according to temperature are provided as temperature detection means. However, either the temperature sensor 183 or the like and the temperature sensitive sheet 191 or the like may be provided as temperature detection means to detect the heating abnormality of the heating unit 18.

[0033] Further, when dew condensation is prevented by the heating unit in the light transmitting unit, a temperature detection means may be provided in the light transmitting unit to detect the heating abnormality of the heating unit. If the heating unit and the temperature detection means are provided in at least one of the light transmitting unit and the light receiving unit, the effect of detecting the heating abnormality can be obtained. In the embodiment, the heating abnormality due to the heater 182 not dissipating heat is detected, but the heating abnormality due to excessive heat dissipation by the heater 182 can also be detected.

[0034] In the embodiment, the temperature sensitive sheet 191 is used by being attached to the heater 182, but it may be provided at another location as long as it is provided at a location that receives the heat of the heater 182. For example, a temperature sensitive sheet may be attached near the heater 182 on the outer surface of the front cover 17. Then, even if the front cover 17 is not removed from the light receiving unit 1, the heating abnormality of the heating unit 18 can be detected. Also, if a temperature sensitive sheet is attached to a position on the outer surface of the front cover 17 away from the heater 182, since the colors are easy to compare, the heating abnormality of the heating unit 18 can be easily detected.

[0035] In addition, in the embodiment, the temperature-sensitive sheet 192 is used together with the temperature-sensitive sheet 191 so that the colors of the two can be compared, facilitating the recognition of heating abnormalities. However, the detection of heating abnormalities may be performed only based on the color of the temperature-sensitive sheet 191 without using the temperature-sensitive sheet 192. Also, the temperature-sensitive sheet 191 and the temperature-sensitive sheet 192 may be integrated, and the detection of heating abnormalities may be performed based on the color difference depending on the position on the large temperature-sensitive sheet.

[0036] In the embodiment, an abnormality in which the heating unit 18 is not heating is detected as a heating abnormality. However, an abnormality in which the heating unit 18 becomes too hot may be detected as a heating abnormality. Furthermore, both an abnormality in which the heating unit is not heating and an abnormality in which it becomes too hot may be detected as heating abnormalities.

[0037] Also, in the embodiment, when a heating abnormality of the heating unit 18 is detected, the warning lamp 157 emits light. However, alternatively, an abnormality signal may be sent to the fire receiver 4. Also, an abnormality signal may be sent to the fire receiver 4 while the warning lamp 157 emits light.

[0038] In addition, the specific configuration is not limited to the embodiment, and design changes and the like within the scope not departing from the gist of the present invention are also included in the present invention. Also, the above-described embodiment and modification examples can be combined by diverting each other's technologies as long as there are no particular contradictions or problems in their purposes and configurations.

Explanation of Reference Numerals

[0039] B Building, 1 Light-receiving part, 11 Connection terminal, 12 Rear panel, 13 Fixed substrate, 131 Rear part, 132 Circuit fixing part, 133 Cover mounting part, 133a Screw hole, 14 Optical member, 141 Lens, 15 Circuit part, 151 Upper board of circuit part, 152 Connection post, 153 Circuit part cover, 154 Circuit board, 155 CPU, 156 Memory, 157 Abnormality lamp, 16 Light-receiving element, 17 Front cover, 171 Light transmission window, 172 Cover fixing screw, 18 Heating part, 181 Heat sink, 181a Side part, 181b Lower part, 182 Heater, 183 Temperature sensor, 184 Heat sink fixing screw, 191 Temperature-sensitive sheet, 192 Temperature-sensitive sheet, 2 Light-transmitting part, 21 Connection terminal, 22 Light-emitting element, 3 Wiring, 4 Fire receiver, 41 Connection terminal, 5 Wiring, 6 Power supply for heater

Claims

1. In a photoelectric separation type detector that senses a fire by a decrease in the amount of received light caused by smoke blocking the emitted light, a heating unit that heats an optical member and temperature detection means that detects the temperature of the heating unit are provided in at least one of a light transmitting unit and a light receiving unit, and the temperature detection means detects an abnormal heating of the heating unit. A photoelectric separation type detector characterized by the above.

2. A temperature sensor as the temperature detection means, and a CPU are provided. An abnormal heating of the heating unit is detected by a temperature difference between the CPU temperature detected by a CPU temperature sensor provided in the CPU and the heating unit temperature detected by the temperature sensor. The photoelectric separation type detector according to claim 1, characterized by the above.

3. When an abnormal heating of the heating unit is detected, an abnormal lamp is caused to emit light or an abnormal signal is sent to a fire receiver. The photoelectric separation type detector according to claim 2, characterized by the above.

4. The abnormal heating is an abnormality in which the heating unit is not heating. The photoelectric separation type detector according to claim 1, characterized by the above.

5. As the temperature detection means, a temperature-sensitive sheet that changes color according to temperature is provided. The photoelectric separation type detector according to any one of claims 1 to 4, characterized in that the temperature-sensitive sheet is provided in the vicinity of the heating unit and at a location separated from the heating unit.

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