JP2009301395A - Thermal fire alarm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal fire alarm, which is enhanced in designability without deterioration of thermal responding performance. <P>SOLUTION: The thermal fire alarm 1 includes a box-shaped body 10, a current plate 30 disposed with a space from one surface 11 of the body 10, and a thermal sensor 25 for detecting heat of a fire provided to protrude from the one surface 11 of the body 10 toward the current plate 30. At least a part of the periphery of the current plate 30 is located inside the periphery of the one surface 11 of the body 10 in a plan view. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thermal fire alarm that is installed indoors such as a house and detects the heat and issues a fire alarm when a fire occurs inside the house.

  The above-mentioned thermal fire alarm measures the temperature of the atmosphere in the space in which it is installed using a thermistor or other heat detection element, and the occurrence of a fire in the installation space based on the measured temperature of the atmosphere. For example, Patent Document 1 proposes such a thermal fire alarm.

  6 and 7 show a thermal fire alarm 400 proposed in Patent Document 1. FIG. In FIG. 6, reference numeral 410 denotes a main body of the thermal fire alarm 400. The case of the thermal fire alarm 400 is constituted by the main body 410 and the cover 420 engaged therewith. A protector 430 is locked on the upper surface of the cover 420. As shown in FIG. 7, the protector 430 has an annular wall 431 whose center side is raised, eight thin pillars 432 extending obliquely upward from the inner peripheral edge of the annular wall 431, and the tips of these pillars 432 are external. The ring 433 is connected to the periphery, and four projecting pillars 434 that extend horizontally from the inner periphery of the ring 433 toward the center.

  In a case constituted by the main body 410 and the cover 420, a printed circuit board 440 on which a semiconductor thermal element (that is, a thermal sensor) 460 such as a thermistor is mounted is provided. An element support 450 for supporting the thermal element 460 is provided on the printed board 440 so as to penetrate the cover 420. The element support base 450 supports the lead wires 462a and 462b of the thermal element 460 so as to rise from the printed circuit board 440, and the air circulation space K in which the thermal part 461 of the thermal element 460 is surrounded by the cover 420 and the protector 430. Is positioned.

  Four blade fittings 472 are provided on the lower surface of the main body 410, and the blade fittings 472 and the printed circuit board 440 are fixed to the main body 410 by four screws 470. The thermal fire alarm 400 is fixed to the base 480 by rotating and connecting the blade bracket 472 to a blade bracket 481 provided on the base 480 fixed to a wall (not shown) with screws. The A power and signal line is connected to the blade bracket 481.

  According to the thermal fire alarm 400, the printed circuit board 440 can be electrically connected to the blade bracket 481 to which the power / signal line is connected via the screw 470 and the blade bracket 472, so that soldering is unnecessary. It was easy to assemble.

  However, the above-described thermal fire alarm 400 has a mechanical appearance such that the thermal element 460 positioned in the air circulation space K surrounded by the protector 430 is visible to the user. There was a problem that the aesthetics were spoiled, such as being in harmony with the interior of the room where the fire alarm 400 was installed.

  Thus, as a result of intensive investigations focusing on the shape of the protector that protects the thermosensitive element (that is, the thermal sensor), the present inventors have come up with the following thermal fire alarm.

  A thermal fire alarm 500 shown in FIG. 8 is attached to the tip of a box-shaped main body 510 and a plurality of mounting bosses 512 erected from the surface 511 of the main body 510, and is spaced from the surface 511 of the main body. It has a rectifying plate 530 that is open and a thermal sensor 525 that detects the heat of a fire projecting from the surface 511 of the main body toward the rectifying plate 530. This baffle plate 530 is formed in the same shape as the plan view of the surface 511 of the main body, its lower end 530A is positioned opposite to the lower end 511A of the main body surface 511, and its upper end 530B is the upper end of the main body surface 511. Positioned relative to 511B, that is, the current plate 530 is overlapped with a gap so as to cover the entire surface 511 of the main body. The rectifying plate 530 forms a rectifying path 518 that guides the atmosphere to the thermal sensor 525 between the rectifying plate 530 and the surface 511 of the main body. By this rectifying path 518, the atmosphere flowing from below or above is smoothly guided to the thermal sensor 525 with respect to the thermal fire alarm 500 installed on the wall surface.

Since the thermal fire alarm device 500 includes the rectifying plate 530, the thermal fire alarm device 500 can protect the thermal sensor 525 and hide it from the user. It is possible to apply a design such as affixing the same wallpaper as the wall surface to which the thermal fire alarm 500 is attached to the surface 530C to the surface opposite to the surface 511 of the main body. I was able to keep the beauty of the 500 in harmony with its surroundings.
JP-A-8-287374

  However, due to the convection of the atmosphere generated at the time of the fire, as shown in FIG. 9, the thermal fire alarm 500 installed on the wall surface is orthogonal to the surface 530C of the rectifying plate 530 (that is, the left side of FIG. 9). In this case, the rectifying plate 530 is provided so as to cover the entire surface 511 of the main body so as to cover the entire surface 511, so that the atmosphere flows into the rectifying path 518. Without entering, it passes through the side of the main body 510 and flows toward the wall surface W, and there is a problem that the thermal response performance (that is, thermal sensitivity) is lowered and the detection of fire is delayed. It was.

  The present invention aims to solve the above problems. That is, an object of the present invention is to provide a thermal fire alarm capable of improving design without reducing thermal response performance.

  In order to achieve the above-mentioned object, the invention described in claim 1 includes a box-shaped main body, a current plate arranged at a distance from one surface of the main body, and the current plate from the one surface of the main body. A thermal sensor that detects the heat of a fire projecting toward the fire, and in a plan view, at least a part of the periphery of the rectifying plate is formed on the one surface of the main body. It is a thermal fire alarm characterized by being arranged inside the periphery.

  According to a second aspect of the present invention, in the first aspect of the invention, in addition to the peripheral edge of the rectifying plate facing the part of the peripheral edge of the rectifying plate and the thermal sensor in plan view. Is arranged so as to overlap a part of the peripheral edge of the one surface of the main body.

  The invention described in claim 3 is the invention described in claim 1, wherein, in a plan view, the periphery of the rectifying plate that faces the part of the periphery of the rectifying plate across the thermal sensor is disposed. Another part is arrange | positioned outside the periphery of the said 1st surface of the said main body, It is characterized by the above-mentioned.

  The invention described in claim 4 is the invention described in any one of claims 1 to 3, wherein a cutout is provided in the part of the periphery of the rectifying plate. It is.

  According to the first aspect of the present invention, the thermal sensor can be hidden from the user by the current plate, and at least a part of the peripheral edge of the current plate is a plan view on one surface of the main body. Since it is arranged inside the peripheral edge of the shape, the atmosphere flowing from the direction orthogonal to the surface of the rectifying plate can be directly applied to one surface of the main body, and up to the thermal sensor along one surface of the main body Can lead. In addition, the flow rate of the atmosphere decreases when the atmosphere hits one surface of the main body, and the flow rate of the atmosphere flows in the vicinity of each of a pair of opposing ends of the rectifying plate (that is, a part of the periphery and another part of the periphery). Because the difference occurs, an atmosphere with a low flow velocity is drawn into an atmosphere with a high flow velocity, and a flow from one end portion of the rectifying plate to the other end portion can be generated between the rectifying plate and one surface of the main body. The atmosphere can be actively guided to the thermal sensor. Therefore, the design can be improved without deteriorating the thermal response performance.

  According to the second and third aspects of the present invention, in a plan view, the rectification that faces a part of the peripheral edge of the rectifying plate disposed inside the peripheral edge of the planar view on one surface of the main body with the thermal sensor interposed therebetween. Since the other part of the plate is positioned so as to overlap with a part of the peripheral edge of the one surface of the main body or outside the peripheral edge of the one surface of the main body, the atmosphere in the vicinity of the other part of the peripheral edge of the current plate Can be passed through the side of the fire alarm without touching one side of each other, so each of a pair of opposing ends of the baffle plate (ie, part of the rim and other part of the rim) A large difference can be caused by the flow velocity of the atmosphere flowing in the vicinity, and therefore the atmosphere can be positively guided by the thermal sensor.

  According to the invention described in claim 4, since the notch is provided in a part of the peripheral edge of the rectifying plate disposed inside the peripheral edge of the planar view on one surface of the main body, the one surface of the main body and the rectifying plate are provided. As a result, the shape of the atmosphere flowing in the vicinity of each of a pair of opposing ends of the rectifying plate (that is, a part of the periphery and another part of the periphery) can be changed. A large difference is caused by the flow velocity, and the atmosphere can be positively guided by the thermal sensor. In addition, by arranging the LED and buzzer for notifying the alarm on one side of the main body facing the notch, the rectifying plate does not cover them, so that the visibility of the LED is improved, and the buzzer The sound emission efficiency can be improved by increasing the sound pressure.

  Hereinafter, the thermal fire alarm which shows one Embodiment of this invention is demonstrated with reference to FIGS. 1-3.

  As shown in FIG. 1, the thermal fire alarm 1 (hereinafter, alarm 1) includes a main body 10, a thermal sensor 25, a rectifying plate 30, and a sensor housing 40.

  The main body 10 is formed, for example, in a hollow box shape having a substantially rectangular shape in plan view using a synthetic resin as a material, and is configured to be divided into two parts by a cover 10a and a base 10b as shown in FIG. ing. In the present embodiment, the main body is formed in a box shape having a substantially rectangular shape in plan view. However, the box shape in the present invention is not limited to this shape, for example, in plan view. The shape is arbitrary as long as it is a box shape that can accommodate members necessary for the alarm device, such as an elliptical shape or a polygonal shape, and does not contradict the purpose of the present invention.

  As shown in FIG. 2, the cover 10 a has a surface 11 with a smooth curved surface so that a longitudinal section (that is, a section along the line XX in FIG. 1) is an arc. The base 10b has a substantially U-shaped vertical cross section, and its back surface 16 is formed in a flat shape so that the alarm device 1 can be stably attached to an indoor wall surface. The cover 10a and the base 10b are fixed in a state of being combined with each other by a fixing means such as a tap screw (not shown) and a fixing boss to which the tap screw is screwed.

  The surface 10 of the cover 10a (that is, the surface of the main body 10) is formed such that the vicinity of the center in the vertical direction is a curved surface that protrudes outward from the main body 10, and the lower end 11A of the surface 11 extends from the lower end of the curved surface. And gradually curved and inclined in the direction approaching the back surface 16, and further gradually inclined and curved in the direction approaching the back surface 16 from the upper end of the curved surface to the upper end 11B of the surface 11. Yes. The surface 11 of the main body 10 is smoothly formed from the lower end 11A to the upper end 11B without a seam. On the surface 11, four mounting bosses 12 that support the rectifying plate 30 are vertically erected at intervals. The surface 11 of the main body 10 corresponds to one surface of the main body described in the claims.

  Inside the main body 10, the sensor substrate 13 and the main substrate 14 are respectively fixed by a plurality of ribs 15 that protrude from the inner surface of the main body 10.

  The sensor substrate 13 is arranged in parallel directly under the surface 11 of the main body 10. On the mounting surface of the sensor substrate 13 on the cover 10a side, a thermal sensor 25 is erected vertically to the mounting surface.

  The thermal sensor 25 is a well-known electronic component that includes a heat detection element such as a thermistor and whose output voltage changes depending on the temperature detected by the heat detection element. The thermal sensor 25 is mounted on the sensor substrate 13 so that a tip 25a of the thermal sensor 25 protrudes outward from a through hole (not shown) provided near the center of the surface 11 of the main body 10.

  The main board 14 is arranged in parallel with the sensor board 13 in the vicinity of the center inside the main body 10 with a gap. Mounted on the main board 14 are electronic components that constitute the peripheral circuit of the thermal sensor 25, a microcomputer that receives the output of the thermal sensor 25, determines the occurrence of a fire, and controls the fire alarm. In addition, on the main board 14, an alarm lamp 51, an alarm stop button 52, and an alarm buzzer 53, which will be described later, are mounted on portions corresponding to the lower part of the front surface 11 of the main body 10. Yes. These electronic components are also connected to the above-described microcomputer and controlled.

  The rectifying plate 30 is a rectifying member that forms the rectifying path 18 together with the surface 11 of the main body 10 to guide the atmosphere to the thermal sensor 25 and to regulate the flow thereof. Further, the current plate 30 protects the thermal sensor 25 disposed on the back surface (surface facing the front surface 11 of the main body 10) 30F, or is opposite to the front surface (surface facing the front surface 11 of the main body 10). The surface of 30E is decorated to improve the design. The rectifying plate 30 is formed in a flat plate shape having no opening in consideration of design, and, for example, the same pattern as the wall surface to which the alarm device 1 is attached is provided on the outer surface thereof.

  The rectifying plate 30 is fixed to the front end of the mounting boss 12 using a fixing member (not shown) such as a screw so as to be parallel to the surface 11 of the main body 10 with a gap. In addition, the parallel in the present invention includes a state where two surfaces (including a curved surface as well as a plane) are positioned substantially equidistantly in addition to being strictly parallel. The rectifying plate 30 has a lower end 30A (that is, a part of the peripheral edge of the rectifying plate in the claims) positioned above the lower end 11A of the surface 11 of the main body 10 (that is, the peripheral edge of one surface of the main body in the claims). The upper end 30B (that is, another part of the peripheral edge of the current plate in the claims) is the upper end 11B of the surface 11 of the main body 10 (that is, a part of the peripheral edge of one surface of the main body in the claims). (I.e., overlapped in plan view). Further, both side ends 30 </ b> C and 30 </ b> D of the rectifying plate 30 are positioned substantially opposite to both side ends 10 </ b> C and 10 </ b> D of the surface 11 of the main body 10, respectively. That is, a part of the peripheral edge of the rectifying plate 30 is positioned inside the peripheral edge of the planar view shape on the surface 11 of the main body 10, and another part of the peripheral edge of the rectifying plate 30 is It is positioned so as to overlap a part of the periphery of the surface 11. In addition to this configuration, the upper end 30 </ b> B of the current plate may be positioned outside the upper end 11 </ b> B of the surface 11 of the main body 10. Further, by arranging the rectifying plate 30 in this way, the first portion 112 in which the rectifying plate 30 is stacked at a distance from the surface 11 of the main body 10 and the first portion 112 in which the rectifying plate 30 is not stacked. Two portions 111 are provided.

  The display operation unit 50 is a part for notifying the user of the alarm device 1 of a fire detection state and inputting an operation by the user, and includes an alarm lamp 51, an alarm stop button 52, an alarm And a buzzer 53. These members constituting the display operation unit 50 are disposed on the second portion 111 located below the surface 11 of the main body 10.

  The alarm lamp 51 is composed of, for example, a light emitting element such as an LED. The alarm lamp 51 is turned off when there is no fire, and is activated (lit or blinks) when a fire occurrence is detected. It is a notification means for notifying a fire. The alarm buzzer 53 is composed of, for example, a piezoelectric buzzer capable of outputting a large volume, and sounds an alarm sound in synchronization with the operation of the alarm lamp 51 to audibly notify the user of the alarm device 1 of a fire. It is a notification means. The alarm stop button 52 is a circular push button switch for stopping the operation of the alarm lamp 51 and the alarm buzzer 53 when pressed.

  Next, an example of a schematic operation of the alarm device 1 will be described with reference to FIG. FIG. 3 is a diagram schematically showing the flow of the atmosphere in the alarm device 1.

  Since the atmosphere heated by the fire source flows along the wall surface or the ceiling surface, the alarm device 1 is attached to the wall surface W, the ceiling surface, or the like of the space where the fire is detected. When the alarm device 1 is installed on the wall surface, the alarm device 1 detects the atmosphere flowing mainly from the directions of arrows a and b in FIG. When the alarm device 1 is installed on the ceiling surface, the alarm device 1 has an atmosphere rising from the fire source in addition to the atmosphere flowing from the directions of the arrows a and b described above, that is, as shown in FIG. It is necessary to respond quickly to the atmosphere flowing from the direction of arrow c.

  In the alarm device 1 attached to the wall surface W, when the atmosphere flows from the direction orthogonal to the surface 30E of the rectifying plate 30 toward the alarm device 1 (that is, in the direction of arrow c), a part thereof (hereinafter, The atmosphere F1) hits the surface 30E of the rectifying plate 30, and the other part (hereinafter, atmosphere F2) hits the second portion 111 of the surface 11 of the main body 10. There is also an atmosphere (hereinafter referred to as atmosphere F3) that faces the wall surface W without hitting the alarm device 1.

  When the atmosphere F1 hits the surface 30E of the rectifying plate 30, the atmosphere F1 is decelerated, travels along the surface 30E toward the lower end 30A and the upper end 30B of the rectifying plate 30, and merges with the atmospheres F2 and F3. When the atmosphere F <b> 2 hits the second portion 111 of the surface 11 of the main body 10, the atmosphere F <b> 2 is decelerated and flows along the surface 11, and the atmosphere F <b> 21 that is a part of the atmosphere F <b> 2 flows into the rectifying path 18. Led. The atmosphere F3 flows near the upper end 30B of the rectifying plate 30 toward the wall surface W without being decelerated, and the atmosphere F21 flowing into the rectifying path 18 by the flow of the atmosphere F3 A pulling force is generated toward the upper end 30 </ b> B. Therefore, the atmosphere F <b> 21 is drawn out from the rectifying path 18, and a new atmosphere F <b> 21 is drawn into the rectifying path 18 and guided toward the thermal sensor 25.

  When the thermal sensor 25 detects that the temperature of the atmosphere F21 exceeds a predetermined value, the alarm buzzer 53 is sounded simultaneously with the alarm lamp 51 indicating the occurrence of a fire. Thereafter, when the alarm stop button 52 is pressed, the alarm lamp 51 is turned off, and the alarm buzzer 53 stops sounding. In the above-described schematic operation example, the case where the alarm device 1 is attached to the wall surface W has been described, but the same operation is performed even when the alarm device 1 is attached to the ceiling surface.

  As described above, according to the present invention, the thermal sensor 25 can be hidden from the user by the rectifying plate 30, and the lower end 30 </ b> A of the rectifying plate 30 is lower than the lower end 11 </ b> A of the surface 11 of the main body 10. Since it is positioned above, the atmosphere flowing from the direction orthogonal to the surface 30E of the rectifying plate 30 can be directly applied to the second portion 111 of the surface 11 of the main body 10, and the surface 11 of the main body 10 can be applied. To the thermal sensor. Further, since the atmosphere hits the second portion 111 of the surface 11 of the main body 10, the flow velocity of the atmosphere is reduced, and the flow velocity of the atmosphere in the vicinity of the lower end 30 </ b> A and the upper end 30 </ b> B of the rectifying plate 30 is different. Is drawn into the atmosphere having a high flow velocity, and a flow from the lower end 30A of the rectifying plate 30 toward the upper end 30B can be generated in the rectifying path 18 provided between the rectifying plate 30 and the surface 11 of the main body 10. Therefore, the atmosphere can be actively guided to the thermal sensor 25. Therefore, the design can be improved without deteriorating the thermal response performance.

  Further, in plan view, the upper end 30B of the rectifying plate 30 facing the thermal sensor 25 between the lower end 30A of the rectifying plate 30 is disposed so as to overlap the upper end 11B of the surface 11 of the main body 10. The atmosphere in the vicinity of the upper end 30B of the rectifying plate 30 can be flowed so as to pass through the side portion of the alarm device 1 without hitting the surface 11 of the main body 10, and therefore, a pair of opposing end portions ( That is, a large difference can be caused by the flow velocity of the atmosphere flowing in the vicinity of the lower end 30A and the upper end 30B), and therefore the atmosphere can be actively guided by the thermal sensor 25. Further, even when the upper end 30B of the rectifying plate 30 is disposed outside the upper end 11B of the surface 11 of the main body 10, the same effect as described above can be obtained.

  In addition, since the rectifying plate 30 is provided, the inflow characteristics of the atmosphere to the thermal sensor 25 can be improved, and the atmosphere can be reliably guided to the thermal sensor 25 to increase the fire detection accuracy. Further, since the thermal sensor 25 can be protected by the rectifying plate 30, it is possible to prevent a failure of the alarm device 2 due to an impact or the like, and to improve reliability.

  In the present embodiment, the surface 11 of the main body 10 is provided smoothly and continuously. However, the present invention is not limited to this, and any shape that can reliably guide the atmosphere to the rectifying path 18 is possible. For example, the surface 11 of the main body 10 is formed in a single plane, or the surface 11 of the main body 10 is connected to the flat first portion 112 and the first portion at a predetermined angle. Any shape is possible, such as being formed with the planar second portion 111 formed.

  Further, in the present embodiment, the alarm device 1 includes a main body 10 formed in a hollow box shape having a substantially rectangular shape in plan view, and a portion other than the display operation unit 50 provided at the lower portion of the surface 11 (that is, the first The rectifying plate 30 is provided in parallel with the surface 11 so as to cover the portion 112), but is not limited to this shape. For example, as shown in FIG. The main body 210 formed in the shape of a hollow box is provided in parallel with the surface 211 so as to cover the central portion of the surface 211, and the shape is smaller than the planar view shape of the surface 211 and the periphery thereof. The thermal fire alarm device 2 may include a rectifying plate 230 provided with a notch 230a in part. The thermal fire alarm 2 has a thermal sensor (not shown) provided so as to protrude from the surface 211 toward the rectifying plate 230, and an LED 251 that displays a fire detection state and the like. The thermal fire alarm 2 is mainly mounted on the ceiling surface.

  According to the thermal fire alarm device 2, the notch 230 a is provided on a part of the peripheral edge of the rectifying plate 230 disposed on the inner side of the peripheral edge of the planar view shape on the surface 211 of the main body 210. The planar view shapes of the surface 211 and the rectifying plate 230 can be changed (differentiated), and therefore, a pair of opposing ends of the rectifying plate 230 (that is, the notch 230a and the peripheral edge 230b facing the notch 230a). ) A large difference is caused by the flow velocity of the atmosphere flowing in the vicinity of each, and the atmosphere can be actively guided by the thermal sensor. Further, the LED 251 and the buzzer for notifying the fire detection state and the alarm are arranged at the position of the surface 211 of the main body 210 facing the notch 230a, so that the rectifying plate 230 does not cover them, so that the LED 251 Visibility can be improved and sound output efficiency can be improved by increasing the sound pressure of the buzzer.

  The present inventors use the thermal fire alarm device 1 of the present invention, the above-described conventional thermal fire alarm device 400, and the thermal fire alarm device 500 for thermal response performance (that is, thermal sensitivity), Measurements were made.

  The measurement configuration is as follows. Each of the above-mentioned thermal fire alarms is attached to a wall surface, the temperature flowing to the thermal fire alarm in a direction orthogonal to the wall surface (that is, the direction of arrow c in FIG. 3) is 81.25 ° C., and the flow velocity The temperature and time detected by the thermal sensor provided in the thermal fire alarm were measured by applying an atmosphere of 1 m / sec. The measurement results are shown in the graph of FIG.

  From the graph shown in FIG. 5, the thermal fire alarm 1 of the present invention (in the figure, the product (a) of the present invention) is a conventional thermal fire alarm 400 having no rectifying plate (in the figure, the conventional product 1). The result was slightly higher than (b)). This is presumably because the thermal fire alarm 1 of the present invention actively draws the atmosphere into the rectifying path 18 due to the shape of the surface 11 of the main body 10 and the rectifying plate 30 as described above. In addition, the conventional thermal fire alarm 500 (conventional product 2 (c) in the figure) having a configuration in which the rectifying plate is provided so as to overlap the entire surface of the main body is difficult to flow into the rectifying path. Therefore, it was found that the thermal response performance is extremely inferior. From this result, it was found that the thermal fire alarm 1 of the present invention has a thermal response equal to or higher than that of a conventional thermal fire alarm that does not include a rectifying plate.

  In addition, although the thing of the structure provided with a baffle plate is known in a photoelectric fire alarm device, a photoelectric fire alarm device has the light emitting element which irradiates light with respect to atmosphere, and the light receiving element which receives the light by this light emitting element. A photoelectric sensor is used to detect the occurrence of a fire based on the amount of light received by the light receiving element, and a housing that accommodates the photoelectric sensor and allows the atmosphere to flow in and blocks light from the outside. As a result, the photoelectric fire alarm was able to sufficiently protect the photoelectric sensor by this housing and the current plate. On the other hand, since the thermal fire alarm does not need to block external light, it does not have the housing provided in the photoelectric fire alarm described above, and it is necessary to consider the thermal response from the front. For this reason, conventionally, it has been difficult to protect the thermal sensor with a current plate or a housing, but the present inventors have conducted an extensive investigation and sufficiently protect the thermal sensor in the configuration according to the present invention. I found that I can do it.

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, various modifications can be made without departing from the scope of the present invention.

It is a front view of the thermal fire alarm which shows one Embodiment of this invention. It is sectional drawing which follows the XX line of FIG. It is the figure which showed typically the flow of the atmosphere in the thermal fire alarm of FIG. It is a front view of the thermal fire alarm which shows other embodiment of this invention. It is a graph which shows the thermal response performance of a thermal fire alarm. It is sectional drawing of the conventional thermal fire alarm. It is a front view of the protector with which the thermal fire alarm of FIG. 6 is provided. It is sectional drawing of the other conventional thermal fire alarm. It is the figure which showed typically the flow of the atmosphere in the thermal fire alarm of FIG.

Explanation of symbols

1 Thermal fire alarm 10 Main body 11 Surface (one side of main body)
111 2nd part 112 1st part 18 Rectifier 25 Thermal sensor 30 Rectifier plate 50 Display operation part

Claims (4)

A box-shaped main body, a current plate arranged at a distance from one surface of the main body, and a thermal sensor for detecting the heat of a fire projecting from the one surface of the main body toward the current plate, A thermal fire alarm having
In a plan view, at least a part of the peripheral edge of the current plate is disposed inside the peripheral edge of the one surface of the main body.   In plan view, the other part of the periphery of the rectifying plate facing the part of the periphery of the rectifying plate across the thermal sensor is overlapped with a part of the periphery of the one surface of the main body. The thermal fire alarm according to claim 1, wherein the thermal fire alarm is provided.   In plan view, the other part of the peripheral edge of the current plate facing the part of the peripheral edge of the current plate across the thermal sensor is disposed outside the peripheral edge of the one surface of the main body. The thermal fire alarm device according to claim 1.   The thermal fire alarm according to any one of claims 1 to 3, wherein a notch is provided in the part of the periphery of the rectifying plate.

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