heat detector

Abstract

To provide a heat detector that does not compromise the appearance of an attachment region and is not expensive even when it is used in an explosion-proof region and a high temperature region.SOLUTION: A heat detector in an embodiment of the present invention comprises: a sensor unit having a thermistor; a detection unit; and a monitoring wiring that connects between the sensor unit and the detection unit. The detection unit includes: a resistance detection unit to which the monitoring wiring is connected; a fire determination unit that determines a fire from a resistance value signal obtained by the resistance detection unit; and a transmission unit that transmits a determination result of the fire determination unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heat detector that is attached to a ceiling surface or the like. [Background technology]

[0002] A heat detector, one example of a fire detector, detects heat, smoke, etc. and sends a fire signal to a fire receiver. The fire receiver then issues a fire alarm. Many cultural properties are made of materials such as wood, which are vulnerable to fire, so fire prevention measures are important. However, installing fire detectors in cultural properties is not preferred because it significantly affects the aesthetic appearance of the cultural properties.

[0003] For cultural properties, differential distributed heat detectors, such as those described in Patent Document 1, can be used. A differential distributed heat detector uses a thin copper air pipe laid over the fire detection area. It detects a fire by detecting the air expansion inside the air pipe due to the sudden temperature rise caused by a fire. While differential distributed heat detectors are less aesthetically disturbing than standard fire detectors, the copper pipe is widely exposed in the fire detection area, which still impacts aesthetics. Furthermore, differential distributed heat detectors cannot be automatically tested. Furthermore, they only offer differential heat detection, and cannot be converted to constant-temperature detection by software modification. Furthermore, laying the copper pipe requires special construction, which is costly.

[0004] Furthermore, fire detectors used in locations where flammable gases are likely to be generated must have an explosion-proof structure as described in Patent Document 2. Explosion-proof fire detectors have a special structure that prevents flammable gases from entering the circuit board area, which increases their cost. Furthermore, fire detectors used in high-temperature areas must use circuit boards that do not deteriorate even at high temperatures, which also increases their cost. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-145107 [Patent Document 2] Japanese Patent Publication No. 2022-40664 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a heat detector that does not impair the aesthetic appearance of the mounting area and does not incur high costs even when used in explosion-proof areas or high-temperature areas. [Means for solving the problem]

[0007] A heat detector in one embodiment of the present invention comprises a sensor unit equipped with a thermistor, a detection unit, and monitoring wiring connecting the sensor unit and the detection unit, and the detection unit is characterized in that it has a resistance detection unit to which the monitoring wiring is connected, a fire detection unit that detects a fire based on a resistance value signal obtained by the resistance detection unit, and a transmission unit that transmits the detection result of the fire detection unit. [Effects of the Invention]

[0008] According to the present invention, a heat detector can be obtained that can be used in explosion-proof areas and high-temperature areas at low cost without spoiling the aesthetic appearance of the installation location. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a diagram showing a heat detector installed in a cultural property building in Example 1. [Figure 2] FIG. 2 is a block diagram of a detection unit according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view of a sensor unit installed on a ceiling board in the first embodiment. [Figure 4] 10 is a cross-sectional view of a sensor unit installed on a ceiling panel via a mounting base in Modification 1. FIG. [Figure 5] 10 is a cross-sectional view of a sensor unit installed above a ceiling panel in Modification 2. FIG. [Figure 6]Cross-sectional view of a sensor unit installed in the main house in variant example 3. [Figure 7] FIG. 10 is a diagram showing a heat detector installed in a factory having an explosion-proof area in a second embodiment. [Figure 8] FIG. 13 is a diagram showing a detection unit having a display unit in Modification 4. DETAILED DESCRIPTION OF THE INVENTION [Example]

[0010] Figure 1 shows a heat detector 1 installed in cultural property building C. Heat detector 1 is configured with a sensor unit 11 that detects heat and a detection unit 12 connected by monitoring wiring 13. Furthermore, detection unit 12 is connected to a fire receiver 2 via wiring 3. Heat detector 1 detects a fire using detection unit 12 based on the heat detected by sensor unit 11, and reports the fire to fire receiver 2 via wiring 3.

[0011] As shown in FIG. 1, the heat detector 1 has one or more sensor units 11, which are installed on a ceiling panel Cc in the public area P of the cultural property building C. It is preferable that the sensor units 11 are distributed in installation locations according to the area in which they can detect heat. Furthermore, the detection unit 12 is installed in the backyard B. The monitoring wiring 13 connecting the sensor units 11 and 12 runs above the ceiling panel Cc. In the public area P, the protective tube 112 of the sensor unit 11, which is part of the sensor unit 11, is visible, but the monitoring wiring 13 and the detection unit 12 are not visible from the public area P.

[0012] The sensor unit 11 does not have a circuit board. On the other hand, the detection unit 12 has a circuit board. FIG. 2 shows a block diagram of the detection unit 12. In the detection unit 12, a resistance detection unit 121, a fire determination unit 122, and a transmission unit 123 are formed by circuits on the circuit board. The circuit on the circuit board in Example 1 includes a CPU and memory. The resistance detection unit 121 is connected to the monitoring wiring 13, and is connected to the fire determination unit 122 inside the detection unit 12. Furthermore, the fire determination unit 122 is connected to the transmission unit 123 inside the detection unit 12. The transmission unit 123 is connected to wiring 3.

[0013] The detection unit 12, which includes a circuit board that forms a resistance detection unit 121, a fire determination unit 122 that determines whether a fire has occurred based on the resistance value obtained by the resistance detection unit 121, and a transmission unit 123 that transmits the determination result of the fire determination unit 122, is installed in the backyard B. Therefore, the detection unit 12 is not exposed in the public area P, and the sensor unit 11 installed in the public area P can have a small, inconspicuous appearance.

[0014] The sensor unit 11 of Example 1 is attached to a ceiling panel Cc as shown in Fig. 3. In the sensor unit 11, a thermistor 111 is housed in a protective tube 112. The thermistor 111 is connected to a monitoring wiring 13 inside a base 113 provided at the base end of the protective tube 112. In Fig. 3, the monitoring wiring 13 is shown as a single line, but the monitoring wiring 13 is actually made up of two conductors: a voltage application line and a ground line. In addition, two mounting springs 114 extend from the base 113 in the direction opposite to the protective tube 112.

[0015] The mounting springs 114 are bent at multiple locations. The mounting springs 114 are attached diagonally outward from the base 113. To attach the sensor unit 11 to the ceiling board Cc, a hole H is drilled in the ceiling board Cc. The two mounting springs 114 of the sensor unit 11 are then tightened and inserted into the hole H from the underside of the ceiling board Cc, all the way to the base 113. The mounting springs 114 expand inside the hole H and are locked at their bent portions. Only the thin protective tube 112 of the sensor unit 11 and a portion of the base 113 are exposed from the ceiling board Cc. The base 113 is not entirely exposed, and the mounting springs 114 are located behind the ceiling board Cc, i.e., in a location that is not visible from the installation location. This reduces the amount of heat detector 1 exposed at the installation location. The area of ​​the base 113 exposed below the ceiling board Cc is small. Therefore, the sensor unit 11 does not substantially spoil the aesthetics of the installation location. The sensor unit 11 of the first embodiment is effective when the ceiling board Cc is formed of a ceiling board having a certain degree of thickness.

[0016] The resistance detection unit 121 of the detection unit 12 shown in FIG. 2 is connected to the monitoring wiring 13 from the multiple sensor units 11. The resistance detection unit 121 applies a voltage between the voltage application line and the ground line of the multiple monitoring wiring 13 corresponding to each sensor unit 11, detects the resistance value, and outputs a digital resistance value signal to the fire detection unit 122. The resistance value signal indicates the resistance value of the thermistor 111 connected to the end of the monitoring wiring 13. When a fire occurs and the temperature rises, the resistance value of the thermistor 111 decreases, reducing the resistance value between the monitoring wiring 13. The resistance value signal output by the resistance detection unit 121 decreases, and the fire detection unit 122 determines that a fire has occurred. If a fire has been determined, the fire detection unit 122 commands the transmission unit 123 to transmit a fire signal. The fire signal is then transmitted from the transmission unit 123 to the fire receiver 2 connected via the wiring 3. The fire receiver 2 receives the fire signal from the wiring 3 and issues a fire alarm. Depending on the characteristics of the thermistor, the resistance value may increase with an increase in temperature, and either type may be used.

[0017] The determination in the fire determination unit 122 is made by software stored in a memory provided in the detection unit 12. The determination software may be a constant temperature type that makes a determination based on a resistance value that indicates the temperature, or a differential type that makes a determination based on a resistance value change rate that indicates the temperature change rate. The temperature and temperature change rate at which a fire is determined may also be determined depending on the installation location and stored in a memory provided in the detection unit 12.

[0018] The heat detector 1 of the first embodiment can be automatically tested. The fire receiver 2 or the detection unit 12 includes an automatic testing unit (not shown) that automatically tests the sensor unit 11. The automatic testing unit determines that the heat detector 1 is abnormal if the resistance value indicated by the resistance value signal input to the fire determination unit 122 is an abnormal resistance value that cannot be obtained by temperature change. If the thermistor 111 or the monitoring wiring 13, etc. is disconnected, or if the monitoring wiring 13, etc. is short-circuited due to poor insulation, an extremely large or small resistance value is detected and determined to be abnormal. The sensor unit 11 that indicates the abnormal resistance value is then identified and displayed on a display unit (not shown) provided in the detection unit 12. Furthermore, the automatic testing unit sends a device abnormality signal to the fire receiver 2.

[0019] In the first embodiment, if any of the multiple sensor units 11 obtains a high resistance value, the fire determination unit 122 causes the transmission unit 123 to transmit a fire signal. Therefore, the occurrence of a fire is notified to the fire receiver 2, but which sensor unit 11 detected the fire is not communicated to the fire receiver 2. If an identification number is assigned as a unique number that enables each sensor unit 11 to be identified, and it is determined which sensor unit 11 obtained a high resistance value, an identification signal of the sensor unit 11 that has determined there is a fire is transmitted from the transmission unit 123, and which sensor unit 11 detected the fire is communicated to the fire receiver 2, it becomes possible to identify the sensor unit 11 that detected the fire from the multiple sensor units 11.

[0020] <Variation 1> Modification 1 is a modification of the sensor unit 11 in Example 1. The configuration of the detection unit 12 and the like is the same as in Example 1. In cases where the ceiling board Cc is thin or where it is desired to hide the lower edge of the hole H provided in the ceiling board Cc, the sensor unit 14 and mounting base 15 shown in FIG. 4 can be used instead of the sensor unit 11. The mounting base 15 includes a cylindrical portion 151 and a flange portion 152. The mounting base 15 has two mounting springs 153 on the side of the cylindrical portion 151 opposite the flange portion 152. The two mounting springs 153 are attached obliquely outward from the cylindrical portion 151.

[0021] When attaching the sensor unit 14 to the ceiling board Cc, first, the two mounting springs 153 of the mounting base 15 are tightened and inserted from below into the holes H provided in the ceiling board Cc. Then, the mounting base 15 is pushed in until the flange portions 152 abut against the ceiling board Cc. This causes the mounting springs 153 to expand on the upper side of the ceiling board Cc, and the mounting base 15 is fixed to the ceiling board Cc. Then, the base portion 143 of the sensor unit 14 is inserted from below into the inside of the cylindrical portion 151 of the mounting base 15. The mounting base 15 and the sensor unit 14 are locked together by a locking piece (not shown).

[0022] Even in variant 1, the thin protective tube 142 of the sensor unit 11, a portion of the base 113, and the flange portion 152 of the mounting base 15 are exposed from the ceiling board Cc at the installation location. Even in variant 1, the base 113 is not entirely exposed, and the mounting spring 153 is located behind the ceiling board Cc, in a location that is not visible from the installation location, thereby minimizing the amount of heat detector 1 exposed at the installation location. Because the flange portion 152 of the mounting base 15 is thin, it protrudes only slightly from the ceiling board Cc, and the area of ​​its underside is small. Furthermore, the area of ​​the base 143 of the sensor unit 14 exposed below the ceiling board Cc is small. Therefore, the sensor unit 14 and the mounting base 15 do not substantially detract from the aesthetic appearance of the installation location.

[0023] <Variation 2> Modification 2 is another modification of the sensor unit 11 in Example 1. The configuration of the detection unit 12 and other components is the same as in Example 1. To reduce the size of the hole H in the ceiling board Cc, the sensor unit 16 can be attached as shown in FIG. 5. The sensor unit 16 has a protective tube 162, and the thermistor 161 and the monitoring wiring 13 are connected inside the protective tube 162. The protective tube 162 is fixed to a base 163. To install the sensor unit 16 on the ceiling board Cc as shown in FIG. 5, a hole H of approximately the same size and shape as the cross section of the protective tube 162 is opened in the ceiling board Cc. The protective tube 162 is then inserted into the hole H from above the ceiling board Cc and attached to the ceiling board Cc so that the bottom surface of the base 163 is in contact with the top surface of the ceiling board Cc. The sensor unit 16 of Modification 2 can be used when the sensor unit 16 can be inserted into the hole H from above the ceiling board Cc during installation. In variant example 2, the entire base 113 is located behind the ceiling panel Cc, i.e., in a location that is not visible at the installation location, and only the thin protective tube 142 of the sensor unit 11 is exposed at the installation location, thereby minimizing the heat detector 1 that is visible at the installation location.

[0024] <Variation 3> Modification 3 is another modification of the sensor unit 11 in Example 1. The configuration of the detection unit 12 and the like is the same as in Example 1. Fig. 6 shows the sensor unit 17 of Modification 3, which is attached to a location where there is no ceiling panel Cc in the cultural property building C2. Fig. 6 is a cross-sectional view of the vicinity of the roof of the cultural property building C2. The cultural property building C2 shown here does not have a ceiling panel Cc, and the roof panel R and purlin U of the roof material are exposed.

[0025] The sensor unit 17 is fixed to the side of the purlin U. Figure 6 shows the sensor unit 17 screwed to the purlin U. A flange portion 174 extending laterally from a base portion 173 of the sensor unit 17 is screwed to the purlin U with screws 175. In Figure 6, only the flange portion 174 of the sensor unit 17 is shown in cross section, and the base portion 173 and protective tube 172 are shown from the side. The thermistor 171 is not shown because it is inside the protective tube 172.

[0026] In order to detect heat, the copper pipe of the differential distributed heat detector must be laid horizontally along the side of the main building U, and must be placed in a position that is visible from the installation location. On the other hand, in variant 3 shown in Figure 6, the monitoring wiring 13 can be installed along the main building U, on top of the main building U, etc. Furthermore, the sensor unit 17 in Figure 6 is inconspicuous because only the protective tube 172 and a portion of the base 173 are exposed below the main building U, and does not detract from the aesthetic appearance of the cultural property building C2. [Example]

[0027] Figure 7 shows a heat detector 4 installed in a factory with an explosion-proof area. In Figure 7, the heat detector 4 is installed in a factory building F which has an explosion-proof area E and a non-explosion-proof area S. The heat detector 4 is configured so that a sensor unit 41 that detects heat and a detection unit 42 are connected by monitoring wiring 43. Furthermore, the detection unit 42 is connected to the fire control unit 2 via wiring 3. The heat detector 4 detects a fire using the detection unit 42 based on the heat detected by the sensor unit 41, and reports the fire to the fire control unit 2 via wiring 3.

[0028] As shown in Fig. 7, the sensor unit 41 of the heat detector 4 is installed on a ceiling board Ec in an explosion-proof area E of a factory building F. The detection unit 42 is installed in a non-explosion-proof area S. The monitoring wiring 43 connecting the sensor unit 41 and the detection unit 42 runs above the ceiling board Ec.

[0029] The configuration of sensor unit 41 is the same as that of sensor unit 11 in Example 1, and no circuit board is provided. The circuit board is provided in detection unit 42. Detection unit 42 has a resistance detection unit (not shown) to which monitoring wiring 43 is connected, a fire determination unit (not shown) that determines a fire based on the resistance value obtained by the resistance detection unit, and a transmission unit (not shown) that transmits the determination result of the fire determination unit. Detection unit 42 is also configured similarly to detection unit 12 in Example 1, and determines a fire based on the resistance value generated in a thermistor (not shown) in sensor unit 41, and transmits a fire signal to fire receiver 2 via wiring 3.

[0030] Furthermore, a fire detector 5 is installed in the non-explosion-proof area S and is connected to the fire receiver 2 via wiring 3. The fire detector 5 has a circuit board inside. The fire receiver 2 receives fire signals from the detection unit 42 and the fire detector 5 and issues a fire alarm.

[0031] The sensor unit 41 installed in the explosion-proof area E does not have a circuit board. Therefore, there is an extremely small possibility that the flammable gas in the explosion-proof area E will ignite and explode. Note that the sensor unit 41 may be replaced by the sensor unit of the modified example shown in the first embodiment.

[0032] <Variation 4> Modification 4 is a modification of the detection unit 42. FIG. 8 shows a heat detector 6 including a detection unit 62 which is a modification of the detection unit 42 in Example 2. In the heat detector 6 of the modification, multiple sensor units 61 are connected to each other by monitoring wires 63. Four sensor units 61 provided in the explosion-proof area E are connected to one detection unit 62 by four monitoring wires 63. The detection unit 62 is installed in the non-explosion-proof area S. Wiring 3 is connected to the detection unit 62, and a fire signal is transmitted to the fire control panel 2.

[0033] The detection unit 62 is provided with a plurality of display units 624. The area corresponding to the sensor unit 61 that detected the fire can be displayed. As shown in FIG. 8, the sensor units 61 are installed in four areas, namely, line A, line B, room C, and line D, and when a fire is detected, the corresponding display unit 624 lights up in red. The detection unit 62 also has an automatic test function, similar to the first embodiment. The display unit 624 lights up in yellow the area indicating the sensor unit 61 that detected the abnormality. The detection unit 62 of the modified example can display where the fire occurred in the explosion-proof area E and which sensor unit 61 the abnormality occurred in.

[0034] In Example 2, the heat detector 4 was installed in a factory building F with an explosion-proof area E, but the heat detector 4 may also be installed in a building with a high-temperature area. In that case, the sensor unit shown in the examples and modifications is installed in the high-temperature area, and the difference in temperature between normal and fire conditions is detected to determine whether a fire has occurred, making it possible to detect a fire while preventing false fire alarms even in high-temperature areas where high temperatures are always detected. The detection unit is installed in the normal-temperature area. Because the sensor unit does not have a circuit board, the circuit on the circuit board will not deteriorate due to the temperature in the high-temperature area.

[0035] In the first and second embodiments, a plurality of sensor units are connected to one detection unit, but a heat detector may be formed by connecting one sensor unit to one detection unit.

[0036] Furthermore, the specific configuration is not limited to the embodiments, and the present invention includes design changes within the scope of the gist of the present invention. Furthermore, the above-mentioned examples and modifications can be combined by utilizing each other's technology as long as there are no particular contradictions or problems in the purpose, configuration, etc. [Explanation of symbols]

[0037] C Cultural property building, Cc Ceiling board, P Public area, B Backyard, H hole, C2 Cultural property building, U main building, R roof panel, F Factory building, E Explosion-proof area, Ec Ceiling panel, S Non-explosion-proof area, 1 heat detector, 11 sensor part, 111 thermistor, 112 protective tube, 113 base part, 114 mounting spring, 12 detection unit, 121 resistance detection unit, 122 fire determination unit, 123 transmission unit, 13 monitoring wiring, 14 sensor part, 141 thermistor, 142 protective tube, 143 base part, 15 Mounting base, 151 Cylindrical portion, 152 Flange portion, 153 Mounting spring, 16 sensor part, 161 thermistor, 162 protective tube, 163 base part, 17 sensor part, 172 protective tube, 173 base part, 174 flange part, 175 screw, 2 fire receivers, 3 wiring, 4 Heat detector, 41 Sensor unit, 42 Detection unit, 43 Monitoring wiring, 5 fire detector, 6 Heat detector, 61 Sensor unit, 62 Detection unit, 624 Display unit, 63 Monitoring wiring

Claims

1. a sensor unit including a thermistor, a detection unit, and a monitoring wiring connecting the sensor unit and the detection unit; The heat detector is characterized in that the detection unit has a resistance detection unit to which the monitoring wiring is connected, a fire judgment unit that judges a fire based on the resistance value signal obtained by the resistance detection unit, and a transmission unit that transmits the judgment result of the fire judgment unit.

2. The sensor unit is housed in a protective tube and is exposed to the underside of the ceiling or main building. The detection unit is provided at a position different from the sensor unit and is connected to a fire receiver.

2. The heat detector according to claim 1, wherein the sensor unit is provided in an explosion-proof area and the detection unit is provided in a non-explosion-proof area.

3. 3. The heat detector according to claim 2, wherein the detection unit identifies a sensor unit that has determined that a fire has occurred.

4. 4. The heat detector according to claim 1, wherein the detector performs an automatic test.

5. A heat detector as described in claim 4, characterized in that a plurality of sensor units are connected to the detection unit, and the automatic test detects abnormal resistance values ​​that cannot be obtained by temperature changes, thereby identifying the abnormal sensor unit.

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