thermal sensor

Abstract

To provide a heat detector capable of eliminating a visibility direction property of a display lamp.SOLUTION: A heat detector where a circuit board in which a heat sensitive element and components constituting a circuit for detecting fire are mounted is stored inside a housing made from a body case and a body cover, and a plurality of light-emitting elements that emit light when detecting the fire are provided in the circuit board comprises a display part for displaying fire detection with light emitted by the plurality of light-emitting elements. The heat detector is a thermistor. The display part formed from a transparent material comprises a cone-shaped display lamp member widening in a direction apart from the circuit board from a large insertion hole whose inner diameter is larger than a diameter of the thermistor, and an edge end of the insertion hole. The thermistor is mounted on the circuit board in such a manner that a tip part side passes through the insertion hole. A plurality of light sources located on a circuit board side of the display lamp part are arranged so as to surround the thermistor. A whole surface of the display lamp part is made to emit light by light emitted by the light-emitting elements.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a heat detector equipped with an indicator light, and more particularly to a technique that is effective when applied to a heat detector equipped with a display unit having a cone-shaped indicator light member. [Background technology]

[0002] There are various types of fire detectors used in fire alarm systems installed inside buildings, including heat detectors using thermistors, photoelectric smoke detectors, and flame detectors that have elements such as infrared sensors and detect flames by capturing light of wavelengths specific to flames. All types of fire detectors are equipped with an operation indicator light that shows that the detector has detected a fire, and a status indicator light that shows any malfunctions or other conditions. Conventionally, fire detector indicator lights have often been installed in one location on the surface of the detector using a point-emitting type LED (light-emitting diode). Such point-emitting type indicator lights have a directional visibility, and the indicator light cannot be seen depending on the direction from which it is viewed. Therefore, unless the operation indicator light is installed facing the entrance in a position that is visible when the entrance door is opened, it becomes time-consuming to check the operation of the detector when a fire is detected.

[0003] To address this issue, some detectors have multiple point-emitting LEDs on the cover of the detector to eliminate the visual directional constraints of the indicator light, or have a point-emitting LED installed on the top of the detector, or have a ring-shaped indicator light installed on the flat part of the detector cover, as in the invention of Patent Document 1. Such detectors are easy to install, as there is no need to consider the relationship between the position of the indicator light and the position of the entrance / exit. On the other hand, the operation indicator light of a fire detector is turned off by a "recovery" switch provided on the receiver, so after operating the recovery switch, the detector that sent out the fire signal cannot be identified by the operation indicator light. However, there are some detectors that can store information that a fire signal has been sent and turn the operation indicator light back on after the recovery switch is operated (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-188543 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-134704 Summary of the Invention [Problem to be solved by the invention]

[0005] If a detector like the one in Patent Document 1 has the function of storing information that a fire signal has been sent when it has been sent and of re-illuminating the operation indicator light when necessary, there is a risk that when a person other than the relevant parties finds the operation indicator light in a re-illuminated state, they may assume that a fire has occurred or that the detector has been activated for a reason other than a fire, which could cause confusion.It has also become clear that some owners, fearing that such confusion could occur, do not want the detector's operation indicator light to be lit except in the event of a fire. This invention was made against the background described above, and its purpose is to provide a heat detector that eliminates the visual directionality of the indicator light unit, eliminates the need to worry about the installation angle when installing it on a ceiling surface, and allows installation work to be completed in a short time. Another object of the present invention is to provide a heat detector that has a larger light-emitting area than conventional detectors equipped with point-light-emitting indicator lamps, thereby improving visibility. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides: A housing consisting of a main body case and a main body cover that covers the opening side of the main body case houses a circuit board on which components constituting a heat-sensitive element and a detection circuit for detecting fires are mounted, The circuit board is provided with a plurality of light sources that emit light when the detection circuit detects a fire; A heat detector having a display unit that displays the detection of a fire by the light emitted by the plurality of light sources, the heat-sensitive element is a thermistor, the indicator portion is an indicator light member made of a light-transmitting material, the indicator light member having an insertion hole with an inner diameter larger than that of the thermistor and a cone-shaped indicator light portion that widens outward from an edge of the insertion hole in a direction away from the circuit board, The main body cover thermistor and an opening is formed at a position corresponding to the position of the air inlet through which the outside air can flow. thermistor It has a protector that protects the The protector portion is The cover is integral with the main body and is made of an opaque material together with the main body cover. The heat detector is disposed so as to be located below the indicator light member when installed on the ceiling surface of the building, the indicator light member is formed separately from the main body cover and the protector portion and is disposed so as to be housed between the main body cover and the main body case, and the cone-shaped indicator light portion is disposed inside the opening of the main body cover; the thermistor is mounted on the circuit board so as to pass through the insertion hole, The plurality of light sources are configured such that the light emitting portions of the plurality of light sources are mortar-shaped thermistor, The light emitted by the light source mortar-shaped The entire surface of the indicator light is made to emit light.

[0007] With the above-described configuration, when the light-emitting element (light-emitting diode) is turned on while installed on the ceiling surface of a building, the cone-shaped indicator light portion (tapered portion) of the indicator light member (element support member) emits light, making it visible from any direction 360°, eliminating the need for directional visibility. This eliminates the need to worry about the mounting angle when installing on the ceiling surface, allowing the installation work to be completed in a short time. Furthermore, the light-emitting area is larger than that of sensors equipped with conventional point-emitting indicator lights, improving visibility.

[0008] Furthermore, since the mortar-shaped annular tapered portion around the heat-sensitive element is illuminated as an indicator light, there is no need to provide a separate indicator light that faces the surface of the housing, which makes it possible to make the fire detector smaller. Furthermore, the main body cover has an opening formed at a position corresponding to the heat-sensitive element, and is equipped with a protector part that protects the heat-sensitive element so as to form an inlet through which outside air can flow in.The protector part is arranged so as to be positioned below the indicator light member when the heat detector is installed on the ceiling surface of a building, so that the light emitted from the mortar-shaped indicator light part can be seen through the opening provided in the protector part, and is also reflected by the surfaces of the parts that form the opening (the protector part and the rectifying fins), thereby increasing the apparent light-emitting surface, and improving visibility.

[0009] wherein the plurality of light sources are two light-emitting elements that emit visible light, The two light emitting elements are arranged at positions facing each other with the thermistor at the center. According to this configuration, the entire cone-shaped indicator lamp portion can be made to emit light more uniformly with a smaller number of light-emitting elements than when only one light-emitting element is used.

[0012] Preferably, the indicator light member is disposed inside the base of the protector portion. And above The mortar-shaped indicator light portion is arranged so as to be positioned at the With this configuration, the light emitted from the cone-shaped indicator light section is visible through the opening in the protector section, and is also reflected off the surfaces of the parts that form the opening (the protector section and the rectifying fins), increasing the apparent light-emitting surface, thereby improving visibility. Furthermore, because the cone-shaped section is used as an indicator light, the entire sensor can be made smaller than in a configuration in which a ring-shaped indicator light is formed from a separate member and attached to the main body cover. [Effects of the Invention]

[0013] The heat detector of the present invention eliminates the need for a visual direction for the indicator light, eliminating the need to worry about the mounting angle when installing it on a ceiling surface, and allowing for quick installation. Furthermore, the light-emitting area is larger than that of conventional detectors equipped with point-light indicator lights, improving visibility. [Brief explanation of the drawings]

[0014] [Figure 1] 1A and 1B show a first embodiment in which the present invention is applied to a smoke detection type fire detector, in which (a) is a plan view and (b) is a side view. [Figure 2] 2(a) is a side view showing the components of the housing of the fire detector in FIG. 1 disassembled, and FIG. 2(b) is a plan view of the main body case that constitutes the housing. [Figure 3] FIG. 2 is a cross-sectional view showing the internal configuration of the fire detector of FIG. [Figure 4] 2 is a perspective view showing a light guide member used in the fire detector of FIG. 1. FIG. [Figure 5] 5A, 5B, and 5C show details of the light guide member of FIG. 4, with (a) being a plan view, (b) being a cross-sectional view, and (c) being a bottom view. [Figure 6] FIG. 4 is a front cross-sectional explanatory view showing the configuration of a heat detector according to a second embodiment of the present invention. [Figure 7] FIG. 10 is a perspective view showing a specific example of an element support member constituting the heat detector of the second embodiment. [Figure 8] 2 is a block diagram showing the functional configuration of a circuit provided on a circuit board in the fire detector of FIG. 1. FIG. [Figure 9] 9 is a time chart showing an example of the operation of a fire alarm system using a fire detector having the circuit of FIG. 8. [Figure 10] 9 is a time chart showing a second operation example of the fire alarm system using the fire detector having the circuit of FIG. 8. [Figure 11] 10 is a time chart showing a third operation example of the fire alarm system using the fire detector having the circuit of FIG. 8. [Figure 12] 10 is a time chart showing a fourth operation example of the fire alarm system using the fire detector having the circuit of FIG. 8. [Figure 13] 1A and 1B are front and rear perspective views showing an example of the configuration of a monitor device for checking the lighting state of an invisible light operation indicator lamp that constitutes a fire detector of an embodiment. [Figure 14] 14 is a perspective view showing a specific example of a lens unit constituting the monitor device of FIG. 13. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. (First Example) FIG. 1 shows a first embodiment in which the present invention is applied to a smoke detection-type fire detector, where (a) is a plan view of the fire detector 10, (b) is a side view, FIG. 2(a) is a side view showing the disassembled housing of the fire detector 10, FIG. 2(b) is a plan view of the main body case 30, FIG. 3 is a cross-sectional view of the fire detector 10 taken along line AA in FIG. 1, and FIGS. 4 and 5 are diagrams showing specific examples of the light guide member constituting the fire detector 10 of FIG. 1. The fire detector 10 of this embodiment is designed to be installed on the ceiling of a building with the upper side (top side) of FIG. 1(b) facing downward. In the following explanation, the downward direction when installed on the ceiling of a building is referred to as "upward."

[0016] 1 and 2(a), the outer shell of the fire detector 10 of this embodiment is made up of a cover 11, a main body case 30, a base 31, and a light guide member 20 sandwiched between the cover 11 and the upper end of the main body case 30. The main body case 30 is made of white resin, and as shown in FIG. 2(b), a circular opening 30b is formed in the center, and the cover 11 is attached to the top of the main body case 30 so as to close this opening 30b. As shown in Fig. 3, a smoke detection box 37 is housed inside the main body case 30, forming a smoke detection chamber 36. A circuit board 32 is attached to the base 31 with screws 38, and the circuit board 32 is housed in the internal space defined by the main body case 30 and the base 31. A light-emitting element 33 and a light-receiving element 34 are mounted on the circuit board 32 via lead wires, and an LED (light-emitting diode) 35 (only one is shown in Fig. 3) serving as a light source for the indicator light is surface-mounted and housed together with the circuit board 32 in the main body case 30.

[0017] As shown in FIG. 1, the outer peripheral wall of the main body case 30 is provided with a plurality of ventilation holes 30d for allowing outside air to flow into the smoke detection chamber . In the fire detector 10 of this embodiment, when smoke is generated by a fire or the like and flows into the smoke detection chamber 36 through the vent 30d, the light emitted from the light-emitting element 33 is scattered by the flowing smoke, and the scattered light is received by the light-receiving element 34, thereby detecting the fire. Furthermore, the circuit board 32 is configured to light up the operation indicator light (light guide member 20, LED 35a) under predetermined conditions when a fire is detected based on the detection signal from the light-receiving element 34.

[0018] As shown in Figures 2(a) and 4, the light guide member 20 consists of a ring-shaped annular portion (light emission portion) 22 and rod-shaped light incident portions 21, 21 extending downward from the annular portion 22, and both the annular portion 22 and the light incident portions 21, 21 are made of a material that allows light to pass through. A circular rib 40 is erected around the opening 30b of the main body case 30, and the outer peripheral surface of this rib 40 contacts the inner peripheral surface 22b of the annular portion 22 of the light guide member 20, forming a first reflective surface (light reflector) that reflects light emerging from the inner peripheral surface 22b. A flat annular surface is formed on the top surface of the main body case 30, extending radially from the first reflective surface with a predetermined width, and forming a flat annular surface in a plan view. This surface contacts the bottom surface 22d of the annular portion 22, forming a second reflective surface (light reflector) that reflects light emerging from the bottom surface 22d. A flat annular surface is formed on the periphery of the back side of the lid portion 11, and this surface contacts the top surface 22c of the annular portion 22, forming a third reflective surface that reflects light emerging from the top surface 22c.

[0019] 2(b) and 3, two fitting holes 30c are formed in the second reflecting surface forming portion that contacts the bottom surface 22d of the annular portion 22 of the main body case 30 to fit the two light incident portions 21 of the light guide member 20. Note that only one fitting hole 30c is shown in FIG. 4, light from the LEDs 35a and 35b is incident on the lower end surfaces of the light incident portions 21 and 21. The lower end surfaces of the light incident portions are formed flat, convex, or concave as shown in FIG. 5(b), and the incident light travels toward the annular portion 22.

[0020] In this embodiment, of the LEDs 35a and 35b facing the light incident portions 21, 21, the LED 35a emits visible light, and the LED 35b emits invisible light. The on / off state of the invisible light status indicator (LED 35b) can be confirmed using an infrared camera or infrared sensor, for example, if the LED 35b emits infrared light. The method of controlling the illumination of the LEDs 35a and 35b will be described later. The invisible light status indicator (LED 35b) is not limited to emitting infrared light, but may also emit ultraviolet light. Furthermore, in a fire detector without a history display function, the two LEDs 35a and 35b may be of a type that emits visible light, or only the LED 35a may be used, omitting the LED 35b. Furthermore, the flashing may be a constant wavelength and a constant duty cycle that does not have any transmission significance.

[0021] 4, the annular portion 22 of the light guide member 20 is composed of an emission surface 22a that emits light to the outside when the light guide member 20 is incorporated into a fire detector, i.e., that serves as an indicator light, an inner peripheral surface 22b, a top surface 22c, and a bottom surface 22d. The emission surface 22a is formed as a slope between the top surface 22c and the bottom surface 22d. In the annular portion 22, V-shaped notches 23 are formed above the light incident portions 21. Light from the light incident portions 21 is reflected by the slopes of the notches 23 and is sent to the annular portion 22.

[0022] The two surfaces forming each of the notches 23, 23 may be formed to have a predetermined angle of approximately the same magnitude relative to a line parallel to the longitudinal direction of the light incident portions 21, 21, as shown in Figure 5(b), or one surface 23a may be formed as a vertical surface and the other surface 23b may be formed as an inclined surface having a predetermined angle relative to the vertical surface. 5(c), a large number of fine grooves (microstructures) 24, 24, 24..., which are uniformly fine hairline grooves, are formed on the bottom surface 22d of the annular portion 22 of the light guide member 20. Light within the annular portion 22 is reflected in various directions by these fine grooves 24, 24...

[0023] The guide member 20 having the above-described structure is incorporated into the fire detector 10 by fitting the two light incident portions 21 into the corresponding fitting holes 30c of the main body case 30 and pressing them down with the lid portion 11, as shown in Figure 3, so that the guide member 20 is sandwiched between the lid portion 11 and the top surface of the main body case 30. The ends of the two light incident portions 21 fitted into the two fitting holes 30c are respectively close to the two LEDs 35a (35b) on the circuit board 32, so that light emitted from each LED 35a (35b) is incident on the light incident portion 21. Specifically, as shown in Fig. 4, the LED 35a is disposed so as to face one end face of the two light incident portions 21, and the LED 35b is disposed so as to face the end face of the other light incident portion 21.

[0024] Furthermore, when the light guide member 20 is incorporated into the fire detector 10, the inner peripheral surface 22b of the annular portion 22 contacts the first reflective surface of the main body case 10, the bottom surface 22d contacts the second reflective surface, and the top surface 22c contacts the third reflective surface of the lid portion 11. Therefore, light that attempts to be emitted to the outside from the inner peripheral surface 22b, the bottom surface 22d, and the top surface 22c is reflected by the first reflective surface 40 and the second reflective surface 41 of the white main body case 10 and the third reflective surface 11d of the lid portion 11, respectively, and returns to the inside of the annular portion 22. This allows light to be emitted efficiently only from the emission surface 22a, resulting in a more visible indicator light. The emission surface 22a of the annular portion 22 of the light guide member 20 is formed at an angle relative to the top surface 22c and the bottom surface 22d, so that when it is set in the fire detector 10, as shown in Fig. 3, it forms an inclined surface that is formed at an angle relative to both the side and bottom surfaces of the detector 10. As a result, when the annular portion 22 emits light as an indicator light, it can be seen from various angles, eliminating the need for a specific viewing direction.

[0025] Furthermore, V-shaped notches 23, 23 are formed in the annular portion 22 of the light guide member 20, so that light from the light incident portions 21, 21 can be efficiently guided to the annular portion 22. Furthermore, a large number of narrow grooves 24, 24... are formed on the bottom surface 22d of the annular portion 22, so that the light inside the annular portion 22 is repeatedly reflected in a more complex manner and is efficiently emitted from the emission surface 22a, resulting in an indicator light with sufficient brightness. In the above embodiment, the light guide member 20 is made of a material that simply transmits light, but light scattering particles that scatter light may be mixed into a transparent material. Also, the hairline grooves formed in the light guide member 20 are not limited to the bottom surface of the annular portion, and may be formed on the bottom surface, top surface, inner peripheral surface, and emission surface as needed.

[0026] (Second Example) FIG. 6 shows the appearance of a second embodiment of the fire detector 10, and FIG. 7 shows a specific example of an element support member 15 that functions as an indicator light and that constitutes the fire detector 10 of FIG. The fire detector 10 of this embodiment is a heat detector that uses a thermistor 18 as a heat-sensitive element and can detect a fire by detecting a change in electrical resistance that occurs when air heated by the heat generated by a fire comes into contact with the thermistor 18, and is configured to be installed on the ceiling surface of a building or the like with the tip of the thermistor 18 facing downward. In the following explanation, the downward direction when installed on the ceiling surface of a building will be described as upward.

[0027] 6, the heat detector 10 of this embodiment comprises a cylindrical main body case 12 with a bottom that has an accommodation recess for accommodating heat-sensing components and can be inserted into an installation opening provided in the ceiling surface of a building, and a main body cover 13 that has a protector part 13A in the center that covers the tip of the thermistor 18 and is connected to the main body case 12 so as to cover the upper opening of the main body case 12, and the main body case 12 and the main body cover 13 form a housing with an internal accommodation space. Although not shown, a terminal block is provided at the bottom of the main body case 12 for electrically connecting wiring arranged on the underside of the ceiling to the internal circuit board.

[0028] The heat detector 10 also includes a circuit board 14 that is accommodated in the accommodation recess of the main body case 12 and fixed to a boss portion on the bottom of the main body case 12 with a screw (not shown), the thermistor 18 is mounted approximately in the center of the circuit board 14, and a cone-shaped element support member 15 is provided that has a cylindrical portion 15a through which the thermistor 18 can be inserted and is joined to the surface of the circuit board 14 with the base of the thermistor 18 inserted therethrough. The thermistor 18 is mounted on the circuit board 14, and a resin 16 is filled and solidified in the cylindrical portion 15a at the bottom of the element support member 15, through which the base of the thermistor 18 is inserted, thereby supporting the base of the thermistor 18.

[0029] The body cover 13 has a body portion that is generally flat and disc-shaped overall, with an opening formed in the center of the body portion, and a protector portion 13A provided to cover the opening from above. The circuit board 14 is made up of a printed wiring board on whose top and bottom surfaces electronic components such as resistors, capacitors, and ICs (semiconductor integrated circuits) that constitute an electronic circuit for fire detection are mounted, and the tips of the two lead terminals of the thermistor 18 penetrate the circuit board 14 at approximately the center of the circuit board 14, protrude from the bottom surface, and are connected to the circuit board 14 by soldering or the like.

[0030] 7, the element support member 15 is formed of a light-transmitting material such as polycarbonate resin, and is provided with a cylindrical portion 15a for inserting the thermistor 18, a tapered portion 15b that widens obliquely upward from the cylindrical portion 15a, and a flange portion 15c that extends horizontally outward from the lower end of the tapered portion 15b. Two cylindrical light incident portions 15e are erected downward from the lower surface of the flange portion 15c. Furthermore, a cylindrical light incident portion 15e is provided on the flange portion 15c of the element support member 15 in correspondence with the positions of the LEDs 35a and 35b mounted on the circuit board 14, and a light reflecting portion 15f is provided on the surface portion corresponding to the light incident portion 15e. The end face of the light incident portion 15e, i.e., the surface facing the LEDs 35a and 35b, is formed into a flat, convex, or concave shape suited to the light-emitting characteristics of the LEDs 35a and 35b so as to sufficiently introduce light from the LEDs 35a and 35b. Note that the light reflecting portion 15f is not shown in FIG. 7.

[0031] Two LEDs (light-emitting diodes) 35a and 35b are surface-mounted on a predetermined portion of the circuit board 14 (a portion facing the end faces of the two light incident portions 15e of the element support member 15). As in the first embodiment, one of the two LEDs 35a and 35b, LED 35a (or 35b), is an LED that emits red light (visible light), and the other LED 35b (or 35a) is an LED that emits infrared light (invisible light) that is invisible to the human eye. An LED that emits light with a wavelength equivalent to ultraviolet light instead of infrared light may also be used. In a fire detector without a history display function, the two LEDs 35a and 35b may be of a type that emits visible light, or LED 35b may be omitted and only LED 35a may be used.

[0032] Although not shown, the element support member 15 may be provided with a plurality of (e.g., three) attachment locking pieces that extend downward from the outer peripheral surface of the tapered portion 15b and have outward claws at their tips, and corresponding portions of the circuit board 14 may be formed with engagement holes through which the claws of the locking pieces can be inserted, so that the element support member 15 can be attached to the circuit board 14 by the locking pieces. Furthermore, a step (recess) 13b is provided on the underside of the opening edge of the disk-shaped main body part of the body cover 13, and the step 13b is configured to be joined to the underside of the flange 15c of the element support member 15. A film or layer with good light reflectivity, such as aluminum, may be formed on the inner surface of the step 13b of the body cover 13 to which the flange 15c is joined.

[0033] The light reflecting portion 15f is a recess (groove) having an inclined surface perpendicular to the tapered portion 15b and a V-shaped cross section, and is formed so as to reflect the light guided from the light incident portion 15e in the inclined direction of the tapered portion 15b and in the circumferential direction of the flange portion 15c. As a result, when the LEDs 35a and 35b are turned on, the entire tapered portion 15b of the element support member 15 emits light, and functions as a circular indicator light forming a mortar shape. The outer peripheral surface of the surface of the element support member 15 facing the circuit board (particularly the tapered portion 15b) may be microfabricated with numerous hairline-shaped fine grooves, so that light hitting the grooves is reflected, causing the entire inner peripheral surface of the tapered portion 15b to emit light more brightly. Microfabricating the element support member 15 also has the effect of making it look like frosted glass, making it impossible to see inside the sensor from the outside. Furthermore, fine particles that diffusely reflect light may be mixed into the material forming the element support member 15.

[0034] The protector portion 13A, which is integrally formed with the main body cover 13, includes a plurality of (e.g., six) rectifying fins 13c that radiate in a plan view and a disk-shaped head cover 13d that connects the tips (top ends in FIG. 6 ) of the rectifying fins 13c. The tip of the thermistor 18 is located in the space surrounded by the plurality of rectifying fins 13c and the head cover 13d, and airflow passes between the rectifying fins 13c. The diameter of the head cover 13d is smaller than the diameter of the base (bottom in FIG. 6 ) of the protector portion 13A, and the sensor is formed to have a trapezoidal shape when viewed from the side. Although the rectifying fins 13c are arranged vertically in FIG. 6 , they may also be arranged horizontally (not shown).

[0035] In the heat detector of this embodiment having the above-described configuration, when the LEDs (light-emitting diodes) 35a, 35b are turned on while the detector is installed on the ceiling of a building, the tapered portion 15b of the element support member 15 emits light, and the light is visible from any direction, i.e., 360°, between the multiple rectifying fins 13c, eliminating the need for directional visibility. This eliminates the need to worry about the mounting angle when installing the detector on the ceiling, allowing for quick installation. Furthermore, the light-emitting area is larger than that of a detector equipped with a conventional point-light indicator, and the light emitted from the tapered portion 15b also hits and reflects off the surfaces of the rectifying fins 13c, increasing the apparent light-emitting surface area, thereby improving visibility.

[0036] Furthermore, in the heat detector 10 of this embodiment, the element support member 15 also serves as an indicator light, so the entire detector can be made smaller than in the smoke detection type fire detector of the first embodiment, in which a ring-shaped indicator light is formed from a separate member from the member (element support) that forms the storage space for the thermistor 18 and is attached to the main body cover. Furthermore, the heat detector 10 of this embodiment is configured to have a mortar-shaped element support member 15 with a relatively large opening through which the thermistor 18 is inserted, thereby improving assembly workability, and since the gap between the inner wall of the cylindrical portion 15a of the element support member 15 and the base of the thermistor 18 is filled with resin, the thermistor 18 can be supported in a stable state, and dust and moisture are less likely to enter the storage space of the circuit board, preventing dust and moisture from adversely affecting the circuit board.

[0037] 8 shows a functional block diagram of the detector circuit 50 formed on the circuit board 32 constituting the fire detector of the first embodiment. The detector circuit of the circuit board 14 constituting the fire detector of the second embodiment can also be configured to have the same configuration except for the fire detection section 52. 8, the detector circuit 50 includes a power supply circuit 51, a fire detection unit 52, a fire detection circuit 53, a control circuit 54, a fire signal generation circuit 55, a self-holding circuit 56, a fire history storage circuit 57, a storage time control circuit 58, indicator light drive circuits 59a and 59b that light up and blink LEDs (light emitting diodes) 35a and 35b to indicate operation, and a control signal detection circuit 60. The blinking by the indicator light drive circuits 59a and 59b may be a constant wavelength and a constant duty ratio that does not have the meaning of transmission.

[0038] The power supply circuit 51 receives voltage from the district circuit line of the fire control receiver (not shown) and supplies power to each part. When the voltage of the district circuit line stops for a predetermined time due to a recovery pulse output by turning on a recovery switch provided on the fire control receiver, the power supply voltage supplied to each part from the power supply circuit 51 drops or stops. In the detector of the first embodiment, the fire detection unit 52 detects smoke using a light-emitting element 33 and a light-receiving element 34 arranged in a dark room into which smoke flows, and in the detector of the second embodiment, it detects heat using a thermistor 18. The fire detection circuit 53 determines whether or not there is a fire based on the output of the fire detection unit 52, and if it determines that there is a fire, it notifies the control circuit 54 of the fire determination.

[0039] The control circuit 54 has a memory for storing a control program and a CPU (Central Processing Unit) for executing the control program. The CPU executes the control program to comprehensively control the sensor circuit 50. The control circuit 54 may be hardware such as a sequencer. The fire signal generating circuit 55 has the function of outputting a fire signal to the fire receiver 30 according to the control of the control circuit 54 when a fire is detected or the output of the self-holding circuit 56, and generates a fire signal, for example, indicating that a district circuit line is short-circuited and a current greater than normal flows.

[0040] The self-holding circuit 56 maintains the state so that when the fire detection circuit 53 determines that there is a fire and a fire signal is output from the fire signal generation circuit 55, the fire signal continues to be output even if the fire detection circuit 53 no longer determines that there is a fire, and can be configured, for example, with a latch circuit. The fire history storage circuit 57 stores, as fire detection history, the processing operation in which the fire detection circuit 53 determines a fire and the control circuit 54 outputs a fire signal, and is configured so that the stored data is not erased even if the power is temporarily cut off by a recovery pulse. The fire history storage circuit 57 can be configured with non-volatile memory such as flash memory or EEPROM (Electrically Erasable Programmable Read-Only Memory). Since the fire history storage circuit 57 only needs to erase the stored data during the time width of the recovery pulse and the amount of data to be stored is small, a self-holding circuit that can retain the state for a certain period of time even if the power is cut off may be used.

[0041] The memory time control circuit 58 includes a timer, starts timing under the control of the control circuit 54, and outputs timing data to the control circuit 54. The memory time control circuit 58 may be configured so that the control circuit 54 sets a timing value, and when the set timing value is reached, the memory time control circuit 58 notifies the control circuit 54. The control signal detection circuit 60 detects control signals (commands) input from the district circuit lines, performs demodulation processing on the signals input from the district circuit lines to decipher the commands, and when a command is detected, notifies the control circuit 14.

[0042] Next, the output of the fire detection signal by the detector circuit 50 and the drive control operation of the indicator light will be explained using the time charts in Figures 9 to 12. In Figures 9 to 12, the output of the fire signal is referred to as "alarm," and the state in which there is no fire signal output is referred to as "normal." Furthermore, "ON" and "OFF" in "timing" refer to the start and end of timing the predetermined time T1 for generating a history display restoration request. Furthermore, "fire display" refers to the display of an alarm on the fire receiver. Although not shown, the memory time control circuit 58 operates while the fire detection history is stored, from the start of the alarm (t1) until after the indicator lights (LEDs 35a, 35b) are turned off.

[0043] FIG. 9 shows a first control operation when the sensor circuit 50 detects the occurrence of a fire. As shown in Figure 9, when the fire detector 10 activates (outputs a fire signal) at timing t1, the operation indicator light (LED 35a) on the visible light side of the fire detector 10 lights up (t2), and the fire receiver starts displaying an alarm (t3). Once the monitor confirms that there is no fire, he operates the recovery switch on the fire receiver at any timing t4, which causes a recovery pulse to be output from the fire receiver to each district circuit line. The recovery pulse stops the voltage on the district circuit line for a predetermined period of time, which cancels the alarm (fire signal output) state held in the self-holding circuit 56 of the detector circuit 50 (t5) and turns off the operation indicator light (LED 35a) (t6). However, even if a recovery pulse is input to the detector circuit 50, the fire detection history is still stored in the fire history memory circuit 57.

[0044] During recovery control, a history display request is internally generated in the control circuit 54. Then, based on the history display request and the stored history, the status indicator light (LED 35b) on the non-visible light side starts to light up or blink (t7). In addition, in the storage time control circuit 58, a timer measures a predetermined period T1 (e.g., 3 to 7 days) from the time of recovery in order to generate a history display recovery request, and when the measurement is completed (t8), the status indicator light (LED 35b) for displaying the history is turned off (t9). Due to the operation of the detector circuit 50 as described above, a supervisor or maintenance manager can patrol the area where each fire detector 10 is installed within a predetermined period T1 after an alarm from the fire receiver, and by checking the operating state of the status indicator light (LED 35b), identify the fire detector 10 that detected the fire. Then, the cause of the fire detection can be investigated.

[0045] As described above, in a fire alarm system using the fire detectors of the above embodiments, if any of the fire detectors 10 makes an erroneous detection, even if a recovery operation is performed midway, the status indicator light will be lit, making it easy to identify the detector that made the detection due to a cause other than a fire, and this can be used to investigate the cause of the detection due to a cause other than a fire. Furthermore, according to the fire alarm system that performs the first control operation, the existing fire receiver can be used, and control of the status indicator light (LED35b) based on the fire detection history can be achieved simply by replacing or modifying the detector.

[0046] FIG. 10 shows a second control operation when the sensor circuit 50 detects the occurrence of a fire. The second control operation is the control operation when the fire detector 10 emits a history display request and a history display restoration request, that is, the control operation at timings t1 to t4, is almost the same as the first control operation in Figure 9, so duplicate explanations will be omitted. In the second control operation, a history display request is issued inside the fire detector 10 by timing a first time length Ta from the time (t5) when the detector 10 is restored. Also, a history display restoration request is issued inside the fire detector 10 by timing a second time length Tb from the time (t7) when the history display request is issued.

[0047] In the second control operation, in order to measure a first time length Ta, a process is added in which the control circuit 54 sets the timer of the storage time control circuit 58 to measure the first time length Ta when recovery control is performed. In addition, in order to measure a second time length Tb, a process is added in which the control circuit 14 sets the timer of the storage time control circuit 58 to measure the second time length Tb when a history display request is issued. In the second control operation, as shown in the time chart of Figure 10, when a monitor confirms that there is no fire and operates the recovery switch at any timing t4, a recovery pulse is output from the fire receiver to each district circuit line. This stops the fire detector 10 from issuing an alarm and the visible light side operation indicator light (LED 35a) from lighting up (t5, t6). However, even if a recovery pulse is input to the fire detector 10, the fire detection history is stored in the fire history storage circuit 57.

[0048] Furthermore, in the second control operation, when a recovery pulse is input, the timer of the memory time control circuit 58 starts timing a first time length Ta (t7). Then, when the first time length Ta has been timed (t8), the timer's timing notification becomes a history display request, and if there is a fire detection history, the non-visible light side status indicator light (LED 35b) starts to light up or flash (t9). At the same time, the timer starts timing a second time length Tb, and when this timing is completed (t10), the history display status indicator light (LED 35b) is turned off (t11).

[0049] By this operation, if a monitor or maintenance manager becomes aware that a fire receiver has issued a false alarm, he or she can patrol the area where each fire detector 10 is installed within a predetermined period of time and check the status indicator light (LED 35b) on the invisible light side to identify the fire detector 10 that has detected a fire due to a cause other than a fire. Then, an investigation can be conducted into the cause of the detection due to a cause other than a fire. According to the second control operation, in addition to the same effects and advantages as the first control operation, the effect of being able to arbitrarily set the display timing of the status indicator light (LED 35b) that displays history based on the history of fire detection can be obtained.

[0050] FIG. 11 shows a third control operation when the sensor circuit 50 detects the occurrence of a fire. The third control operation is substantially the same as the first control operation, except that the history display restoration request is sent from the fire receiver to the fire detector 10 using the same pulse signal (restoration pulse Pe) as the restoration pulse Po. In the third control operation, the control signal detection circuit 60 detects and counts the recovery pulses Po and Pe supplied from the fire alarm receiver via the district circuit line, and stores the count value so that it will not be erased even if the power is cut off by the recovery pulses Po and Pe. The count value can be stored in the nonvolatile memory of the fire history storage circuit 57 so that it will not be erased even if the power is temporarily cut off.

[0051] The control circuit 54 also resets the count values ​​of the recovery pulses Po and Pe from the control signal detection circuit 60 to, for example, "0" when a fire is detected and the fire detection history is stored in the fire history storage circuit 57, and when a predetermined period of time has passed and the history is to be erased. The control circuit 54 also reads the count values ​​of the control signal detection circuit 60 immediately after the recovery pulses Po and Pe are input, and recognizes the recovery pulse Po as a history display request if it is the first time. If it is the second time, the control circuit 54 recognizes the recovery pulse Pe as a history display recovery request.

[0052] In the third control operation, as shown in the timing chart of FIG. 11, when a monitor confirms that there is no fire and operates the recovery switch at any timing t4, a recovery pulse Po is output from the fire receiver to each district circuit line. The recovery pulse Po halts the output of voltage to the district circuit line that powers the fire detector 10 for a predetermined period of time, thereby restoring the fire detector 10 and stopping the alarm and the illumination of the visible light side operation indicator light (LED 35a) (t5, t6). Even after the fire detector 10 is restored, the fire detection history is still stored in the fire history storage circuit 57. Furthermore, at the time of restoration, the control signal detection circuit 60 stores the count value "1" for the recovery pulses Po and Pe, which the control circuit 54 recognizes as a request to display the history. This causes the control circuit 54 to light or start flashing the invisible light side status indicator light (LED 35b) (t7). Furthermore, in the third control operation, after the monitor identifies the fire detector 10 that detected the fire, he or she operates the recovery switch again at any timing t8 to cause the fire receiver to output a recovery pulse Pe. The second recovery pulse Pe is then recognized by the fire detector 10 that detected the fire as a history display recovery request, which causes the history display status indicator light (LED 35b) to turn off (t9).

[0053] If the third or subsequent recovery pulses Po and Pe are input to the fire detector 10 before the history is deleted from the fire history storage circuit 57, the control circuit 54 may be configured to regard the odd-numbered recovery pulses Po as a history display request and the even-numbered recovery pulses Pe as a history display recovery request. With this configuration, for example, by sending the third recovery pulse Po, it is possible to turn on or blink the history display status indicator light (LED 35b) of the fire detector 10 that has detected a cause other than a fire, and by sending the fourth recovery pulse Pe, it is possible to turn off the history display status indicator light (LED 35b) again. As described above, according to the third control operation, the monitor can arbitrarily adjust the period during which the history display status indicator light (LED 35b) of the fire detector 10 that detected a fire is illuminated after recovery. Therefore, the monitor can control the history display status indicator light (LED 35b) to light up or flash only during the period during which the monitor goes on patrol.

[0054] FIG. 12 shows a fourth control operation when the sensor circuit 50 detects the occurrence of a fire. The fourth control operation is similar to the third control operation except that the history display request and the history display restoration request are sent from the fire receiver to the fire detector by a pulse signal P1 with a pulse width longer than the restoration pulse P0. In the fourth control operation, the control signal detection circuit 60 detects and counts the pulse signal P1 having a long pulse width, and stores the count value of the pulse signal P1 so that it will not be erased even if the power supply is stopped by this pulse signal P1.

[0055] The control signal detection circuit 21 also includes, for example, a capacitor that accumulates a predetermined amount of charge when power is supplied, a time constant circuit that discharges the charge of the capacitor at a predetermined time constant while the power is turned off by the pulse signal P1, and a determination circuit that determines whether the signal is a recovery pulse P0 or a pulse signal P1 based on the capacitor voltage after discharge. With this configuration, when the power is turned off by the recovery pulse P0 or the pulse signal P1 and then turned on again, the determination circuit can determine that the capacitor voltage is a recovery pulse P0 if it is within a predetermined range, or a pulse signal P1 if it is within a lower range.

[0056] Meanwhile, the control circuit 54 resets the count value of the pulse signal P1 of the control signal detection circuit 60 to, for example, "0" when a fire is detected and the history is to be stored in the fire history storage circuit 57, and when a predetermined period of time has passed and the history is to be erased. After the restoration pulse P0 or pulse signal P1 is input, the control circuit 54 reads the count value of the control signal detection circuit 60. If the count value is zero, the control circuit 54 recognizes this as the input of the restoration pulse P0, and if the count value is "1," it recognizes this as the input of the first pulse signal P1, i.e., a request for history display. If the count value is "2," the control circuit 54 recognizes this as the input of the second pulse signal P1, i.e., a request for history display restoration.

[0057] Furthermore, in the fourth control operation, in addition to the functions of the fire receiver in the first control operation, a function of outputting a pulse signal P1 having a pulse width longer than that of the restoration pulse P0 is added. For example, the fire receiver may be configured so that a normal press of the restoration switch outputs the restoration pulse P0 to each district circuit line, and a long press of the restoration switch outputs the pulse signal P1 having a longer pulse width to each district circuit line. Alternatively, the fire receiver may be configured to have a dedicated operation unit for outputting the pulse signal P1.

[0058] In the fourth control operation, as shown in the time chart of Fig. 12, when the monitor confirms that there is no fire and operates the recovery switch at any timing t4, a recovery pulse P0 is output from the fire receiver to each district circuit line. When the recovery pulse P0 is output, a temporary power outage occurs, restoring the fire detector 10 to its normal operation and stopping the alarm and the illumination of the visible light side operation indicator light (LED 35a) (t5, t6). On the other hand, in the fourth control operation, after the recovery pulse P0 is input, the control circuit 54 reads the count value of the pulse signal from the control signal detection circuit 60. At times t5 and t6, the count value of the pulse signal is "0," so the control circuit 54 does not perform any special processing. Thereafter, the monitor or maintenance person starts to investigate the cause of the false alarm. At the time of starting, the monitor or maintenance person outputs the first long pulse signal P1 from the fire alarm receiver (t7).

[0059] When the first long pulse signal P1 is output, the fire detector 10 is restored due to a temporary power outage, and the control circuit 54 reads the count value of the pulse signal from the control signal detection circuit 60. When the power supply voltage is input again after the output of the first long pulse signal P1, the count value of the pulse signal is "1," so the control circuit 54 recognizes this as a request to display the history. Furthermore, even after the fire detector 10 is restored, the fire detection history is stored in the fire history storage circuit 57. Based on this information, the control circuit 54 starts lighting or flashing the status indicator lamp (LED 35b) on the invisible light side (t8). This allows monitors to patrol the area where each fire detector 10 is installed and check the operating status of the status indicator light (LED 35b) on the non-visible light side, thereby identifying the detector that has mistakenly detected a fire and investigating the cause of the detection that is not a fire.

[0060] Once the fire alarm that detected a cause other than fire has been identified, the monitors operate the fire receiver to output a second second long-pulse signal P2 from each district circuit (t9). When the second long-pulse signal P2 is output, the fire alarm 10 is restored due to a temporary power outage, and the control circuit 54 reads the count value of the second long-pulse signal P2 from the control signal detection circuit 60. After the second output of the second long-pulse signal P2, when the power supply voltage is input again, the count value of the pulse signal is "2," which the control circuit 54 recognizes as a request for displaying the history. Based on this request, the control circuit 54 turns off the history display status indicator light (LED 35b) (t10). As described above, according to the fourth control operation, the output of pulse signals P1 and P2 from the fire receiver can cause the status indicator light (LED 35b) of each fire detector 10 to display or stop displaying information based on the fire detection history information at any timing.

[0061] Next, an embodiment of the monitor device 70 for checking whether the operation indicator lamp (LED 35b) on the non-visible light side for displaying history is on or off will be described with reference to Figures 13 and 14. Of these, Figure 13(A) is an external perspective view of the monitor device 70 as seen from the front side, Figure 13(B) is an external perspective view of the monitor device as seen from the rear side, and Figure 14 is an exploded perspective view showing a specific example of the lens section. As shown in FIG. 13(A), the monitor device 70 of this embodiment comprises a housing 71 that houses an imaging element such as a CCD or CMOS image sensor and a battery, a lens unit 72 that is provided on the front of the housing 71 and that focuses light from a subject onto the internal imaging element, and a grip (handle unit) 73 that protrudes downward from the bottom surface of the housing 71.

[0062] Here, the imaging element built into the housing 71 should be an infrared imaging element capable of capturing light in the infrared wavelength band if the status indicator light on the non-visible light side for displaying history provided on the sensor to be checked uses an infrared LED as its light source, and an ultraviolet imaging element capable of capturing light in the ultraviolet wavelength band if the light source is an ultraviolet LED. Furthermore, as shown in FIG. 13(B), the monitor device 70 of this embodiment is provided with an image monitor 74 consisting of a liquid crystal display panel or the like on the back of the housing 71, and an operation button 75 for switching the power on and off is provided on the side of the housing 71 or the like. 14, the lens unit 72 includes a lens unit main body 72A and an image blurring filter 72B attached to a front end opening 72a of the lens unit main body 72A. Filter 72B can be made of mesh, frosted glass, or plate-like glass such as textured glass with an uneven surface, or a resin plate made of a transparent resin such as acrylic formed into a grid pattern.

[0063] By providing the filter 72B, it is possible to prevent a person from appearing in the image displayed on the image monitor 74, thereby violating privacy, and also to inform the person in front that the camera is not a normal camera by making the filter 72B visible, thereby giving the person in front a sense of security. Furthermore, the monitor device 70 is equipped with an indicator light capable of emitting invisible light, and can be used when it is desired to check whether the history indicator light of the fire detector is on.

[0064] Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments. For example, in the above embodiments, the LEDs 35a and 35b are disposed facing the end faces of the two light incident portions 21 (15e). However, for example, the end of each light incident portion 21 (15e) may be cut into a mountain shape, and a pair of LEDs 35a and 35b may be disposed facing each cut surface. With this configuration, the amount of light incident on a single light incident portion 21 (15e) is reduced, but light from multiple light incident portions 21 (15e) can be guided to the light emitting portions (22, 15b), allowing the light emitting portions (22, 15b) to emit more uniform light throughout their entire circumference. The diameter of each light incident portion 21 (15e) may be increased, and the LEDs 35a and 35b may be mounted so that their optical axes are perpendicular to the cut surfaces. Furthermore, the LEDs 35a and 35b are not limited to surface-mounted types and may be bullet-shaped.

[0065] In addition, in the above embodiment, the light guide member 20 (15) has two light entrance portions 21 (15e), but the number of light entrance portions 21 (15e) may be three or more. Furthermore, in the above embodiment, the emission surface (indicator light) that emits light from the annular portion 22 (15b) to the outside is circular, but it does not have to be circular and may be elliptical or have a star-like or flower-like shape with multiple bends. Furthermore, the emission surface of the light guide member is not limited to the annular shape described above, but may be in the shape of a disk, a roughly polygonal disk, or the like. In short, it is sufficient if the shape allows the indicator light to be seen from any angle when the fire detector attached to the ceiling is viewed. Furthermore, in the above embodiment, the cause of lighting the invisible light indicator lamp has been described as history display, but this is not limited to this, and the invisible light indicator lamp may also be used, for example, to display a sensor malfunction or a self-diagnosis result.

[0066] [Summary of the invention in the original application] [Other problems to be solved by the invention] Another object of the present invention is to provide a fire detector that will not cause confusion when a person other than the person in charge finds the indicator light in the re-lit state. Another object of the present invention is to provide a fire detector that can store information indicating that a fire signal has been sent in the past and has the function of re-illuminating the signal, and that can be constructed using parts that are common to fire detectors that do not have such a function, thereby reducing costs.

[0067] [Means for solving the above problems] In order to solve the above problems, the present invention provides: a circuit board on which a circuit for detecting a fire is formed; a plurality of light sources connected to the circuit board; a housing that houses the circuit board and the plurality of light sources; and an indicator light that lights up and displays by light from the light source. At least one of the plurality of light sources is a light source that emits visible light, and at least one of the light sources other than the light source that emits visible light is a light source that emits invisible light.

[0068] According to the above-mentioned configuration, at least one of the plurality of light sources is a light source that emits visible light, and at least one of the remaining light sources is a light source that emits invisible light, so that after the recovery switch is operated, the light source that emits invisible light is turned on to re-light the indicator light, i.e., to display the history, making it possible to easily find fire detectors that were activated before the recovery operation and to prevent confusion caused by persons other than those involved finding the activated indicator light in a re-lit state. Furthermore, a fire detector that has the function of storing information that a fire signal has been sent in the past and re-lighting it to display the history can be constructed using parts that are common to fire detectors that do not have such a function, thereby reducing costs.

[0069] Here, the indicator light is made up of a light guide member that includes a plurality of light entrance portions that respectively admit light from the plurality of light sources, a light emitting portion that is approximately annular in shape and has its center approximately at a center line passing through the top of the front surface of the housing when viewed from the front surface side of the housing, and a light guiding portion that guides the light that has entered from the light entrance portions to the light emitting portion. According to this configuration, since the light emitting portion is substantially annular, the indicator lamp has no visual directionality, and the installation work is easy.

[0070] Preferably, the light source that emits the invisible light is a light source that emits light of an infrared wavelength or an ultraviolet wavelength. According to this configuration, the desired light source can be obtained relatively easily, and therefore a significant increase in the cost of the fire detector that would accompany the addition of a history display function can be avoided.

[0071] Preferably, the housing comprises a main body case and a main body cover that covers the opening side of the main body case, a heat-sensitive element is mounted on the circuit board; The body cover has an opening formed at a position corresponding to the heat-sensitive element, and is provided with a plurality of rectifying fins that form an inlet through which outside air can flow in, The light guide member comprises a cylindrical insertion portion having an inner diameter larger than the diameter of the heat-sensitive element, a mortar-shaped tapered portion extending outward from the peripheral end of the cylindrical insertion portion toward the main body cover, and a flange portion extending horizontally outward from the peripheral end of the tapered portion.

[0072] With this configuration, in a heat-sensing fire detector, by re-illuminating the indicator light, i.e., displaying the history, while protecting the heat-sensitive element, it is possible to easily find fire detectors that were activated before the recovery operation, and it is also possible to prevent confusion caused by people other than those involved finding the activation indicator light in a re-illuminated state.In addition, because the member that protects the heat-sensitive element (element support) lights up as an indicator light, there is no need to provide a separate indicator light that faces the surface of the housing, which makes it possible to make the fire detector smaller.

[0073] The light source that emits the invisible light emits light in response to a request to display a state other than the operating state of the fire detector. According to this configuration, the indicator light can indicate an activated state, which indicates that the detector has detected a fire, as well as a state other than the activated state. Here, one of the requests for displaying a status other than the activation status of the fire detector may be activation history information of the fire detector.

[0074] [Effects of the invention] According to the present invention, a fire detector can be provided that prevents confusion when unauthorized persons find the indicator light in the re-illumination state to indicate the detector's status. Furthermore, there is no visual directional requirement, meaning that it is possible to confirm from any direction whether the fire detector is activated or not. Furthermore, according to the present invention, a fire detector that stores information indicating that a fire signal has been sent in the past and has the function of re-illuminating the detector can be constructed using the same components as a fire detector that does not have such a function, which has the effect of reducing costs. [Explanation of symbols]

[0075] 10 Fire detector 11 Lid 20 Light guide member 21 Light incidence part 22 Annular part (light emitting part) 23 Notch (light guiding part) 30 Main unit case 30b opening 31 Base 32 Circuit Board 35a,35b LED (light source) 12 Main unit case 13 Main unit cover 14 Circuit Board 15 Element support member (light guide member) 15b Tapered portion (light emitting portion) 15e Light incidence part 50 Sensor circuit

Claims

1. A housing consisting of a main body case and a main body cover that covers the opening side of the main body case houses a circuit board on which components constituting a heat-sensitive element and a detection circuit for detecting fires are mounted, The circuit board is provided with a plurality of light sources that emit light when the detection circuit detects a fire; A heat detector having a display unit that displays the detection of a fire by the light emitted by the plurality of light sources, the heat-sensitive element is a thermistor, the indicator portion is an indicator light member made of a translucent material, the indicator light member having an insertion hole with an inner diameter larger than a diameter of the thermistor and a cone-shaped indicator light portion that widens outward from an edge of the insertion hole in a direction away from the circuit board, the main body cover has an opening formed at a position corresponding to the thermistor, and includes a protector portion that protects the thermistor and forms an inlet through which outside air can flow in; the protector part is integral with the main body cover, and is formed together with the main body cover from an opaque material, and is disposed so as to be located below the indicator light member when the heat detector is installed on a ceiling surface of a building; the indicator light member is formed separately from the main body cover and the protector portion and is disposed between the main body cover and the main body case, and the cone-shaped indicator light portion is disposed inside the opening of the main body cover; the thermistor is mounted on the circuit board so as to pass through the insertion hole, the plurality of light sources are arranged so that light-emitting portions of the plurality of light sources are located closer to the circuit board than the cone-shaped indicator light portion and surround the thermistor; A heat detector characterized in that the entire surface of the cone-shaped indicator light portion is illuminated by the light emitted by the light source.

2. the plurality of light sources are two light-emitting elements that emit visible light, 2. The heat detector according to claim 1, wherein the two light emitting elements are disposed at positions facing each other with the thermistor at the center.

3. 3. The heat detector according to claim 1, wherein the indicator light member is disposed so that the cone-shaped indicator light portion is positioned inside and above the base of the protector portion.

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