JP5135141B2 - Flame detector - Google Patents

Description

  The present invention relates to a flame detector that performs detection by capturing light having a wavelength specific to a flame.

A conventional flame detector includes a recess that forms a viewing angle of a detection unit that detects a flame, and an operation indicator lamp that is turned on when a flame is detected (see, for example, Patent Document 1 or Patent Document 2).
The operation indicator lamp is connected to the circuit board and is exposed from the position where it does not obstruct the viewing angle of the cover.
Japanese Patent Laid-Open No. 10-320666 Japanese Patent Laid-Open No. 9-184753

  However, the above conventional flame detector has a problem in that it is poor in design, has a large number of parts, and has a complicated structure. Therefore, it is troublesome to manufacture and assemble, and the visibility of the operation indicator lamp is poor. It was.

  It is an object of the present invention to provide an improved flame detector that solves the above problems.

  The invention according to claim 1 is a casing, a circuit board disposed inside the casing and formed with a circuit required for detecting a flame, a main light source connected to the circuit board, and a front surface of the casing A light guide member made of a translucent material that guides light from the main light source to the light emitter through propagation inside, and an opening provided on the front side of the housing In a flame detector comprising: a main detection light-receiving element that receives light having a predetermined wavelength emitted by a flame; and a transmission cover that is provided between the opening and the main detection light-receiving element and transmits light from the outside. A light emitting portion of the light guide member is formed in a substantially annular shape surrounding the main detection light receiving element on the front side of the housing to provide a viewing angle limiting function for limiting the field of view of the main detection light receiving element to a predetermined range. , Across the entire circumference of the substantially annular shape Forming an inner slope inclined toward the main detection light receiving elements, and performs the emission of light from the inner slope.

  The invention described in claim 2 has the same configuration as that of the invention described in claim 1, and the light guide member extends from the substantially annular light emitting portion toward the outside thereof. And a second light guide part extending from the first light guide part to the main light source, and a joint part between the first light guide part and the second light guide part is provided in the casing. It is characterized by being arranged to be hidden.

  The invention described in claim 3 has the same configuration as that of the invention described in claim 2, and the first light guide portion of the light guide member has a flat plate shape, and the light emitting portion and the first light guide. The portion is formed such that the surface opposite to the surface from which light is emitted is continuous on the same plane, and a fine structure portion including a number of fine grooves or fine protrusions is formed on the plane. It is characterized by that.

  The invention according to claim 4 has the same configuration as that of the invention according to claim 3, and the second guide is provided at a position facing the end of the second light guide part of the first light guide part. A V-shaped notch is provided to form two reflecting surfaces for reflecting light traveling along the light portion in a direction along the flat plate surface of the first light guide portion, and the V-shaped notch The opening angle is greater than 90 ° and less than 95 °.

  The invention described in claim 5 has the same configuration as that of the invention described in claim 3 or 4, and the substantially circular portion of the light emitting portion of the light guide member has a mountain shape in cross section. An outer slope is formed over the entire outer circumference of the annular shape.

  The invention according to claim 6 has the same configuration as that of the invention according to any one of claims 3 to 5, and the fine side surface portion of the substantially annular portion of the light emitting portion of the light guide member has the fine structure. The structure portion is formed.

The invention according to claim 7 has the same configuration as that of the invention according to any one of claims 1 to 6 , and an element support for fixing the main detection light-receiving element to the circuit board, and the circuit board. And a guide support for fixing the light guide member. The transmission cover is fixedly sandwiched between the element support and the guide support, and each support is fixed to the circuit board. .

The invention according to claim 8 has the same configuration as that of the invention according to any one of claims 1 to 7 , the main detection light receiving element is an infrared detection element, and a heat source is provided to the infrared detection element. A self-diagnosis control means is also provided for heating the heat source to test the detection function of the infrared detection element.

In the first aspect of the present invention, since the light emitting portion of the light guide member is formed in a substantially annular shape surrounding the main detection light receiving element on the front side of the housing, the light emission state can be changed from all directions around the main detection light receiving element. It can be seen and the visibility can be improved. Note that “substantially annular” is not limited to a circular shape, and indicates an endless continuous shape that can surround the main detection light-receiving element. Moreover, since this light emission part has a viewing angle restriction | limiting function, it is desirable that it is a shape which does not have an angle but consists of a straight line and a curve.
Moreover, since the visibility from all directions is ensured by making the light emitting part substantially annular, it is not necessary to project it greatly from the front, and the thickness of the flame detector is reduced in the front-rear direction (the direction perpendicular to the front of the housing). It is possible to reduce the size of the flame detector.

Furthermore, the invention according to claim 1 emits light to the outside of the housing from the inner slope formed over the entire inner circumference of the light emitting portion of the light guide member. From the viewing angle range, it is easy to see the light emission state, and the visibility can be improved. That is, the display state of the indicator lamp can be confirmed more reliably from within the area where the occurrence of flame is monitored, and the operation display can be performed more appropriately.
Further, visibility can be ensured even from an area (S ′, S ′ in FIG. 13) other than the monitoring area (S in FIG. 13), and the light emission state is viewed from almost all directions centering on the main detection light receiving element. be able to.

  According to the second aspect of the present invention, since the joint portion between the first light guide portion and the second light guide portion of the light guide member is hidden in the housing, the second light guide member does not propagate to the first light guide portion. The light that travels straight along the light guide part may cause the joint part between the first light guide part and the second light guide part to appear brighter than the surroundings. Therefore, it is possible to avoid the phenomenon that the light emitting portion of the light guide member emits light unevenly, and to emit light more uniformly.

  According to the third aspect of the present invention, a large number of fine grooves or fine patterns are formed on a surface opposite to the light emitting surface (hereinafter referred to as “back surface”) of the light emitting portion and the first light guide portion. Since the fine structure formed of protrusions is formed, irregular reflection due to light traveling along a plane can be induced, and the light emission effect due to irregular reflection can be obtained on the light emission surface side, making the light emission surface brighter It is possible to emit light.

  In the invention according to claim 4, since the V-shaped notch having an opening angle larger than 90 ° is provided at a position facing the end portion of the second light guiding portion of the first light guiding portion, the opening angle Compared with the case where the angle is exactly 90 °, it is possible to effectively induce irregular reflection due to the fine structure portion on the back surface, and it is possible to make the light emitting surface emit light more brightly. Also, if the opening angle of the V-shaped notch is larger than 95 °, the effect of transmitting light to a portion away from the second light guide portion is reduced, and the amount of light transmitted from the bottom to the outside increases. There is a possibility that the effect of making the light emitting surface emit light brighter may be reduced, and it is desirable that the light emitting surface is set to 95 ° or less.

  According to the fifth aspect of the present invention, the outer slope is formed over the entire outer circumference of the substantially annular shape so that the cross-sectional shape of the substantially annular portion of the light emitting portion of the light guide member is a mountain shape. If the light guide member that emits light from the inner inclined surface is viewed when the light guide member that emits light from the inner inclined surface is formed, the bottom surface is transmitted through the inner inclined surface. And the end surface along the front-rear direction can be seen, but the region of the end surface along the front-rear direction that appears to be transparent is darker than the region of the bottom surface that appears to be transparent, and the light emission state of the inner slope is uneven. End up. Therefore, by setting the substantially annular outer side to be an inclined surface, it is possible to make almost only the bottom surface visible through the inner slope, and to make the light emission state of the inner slope uniform.

  According to a sixth aspect of the present invention, the fine structure portion is formed on the outer peripheral side surface portion of the substantially annular portion of the light emitting portion of the light guide member. If there is no fine structure on the substantially annular outer peripheral side surface, when the light guide member that emits light from the inner inclined surface is viewed, the outer peripheral side portion that can be seen through the inner inclined surface is visible through the bottom region. The brightness becomes darker than that, and the light emission state of the inner slope becomes uneven. Therefore, by forming the fine structure portion on the outer peripheral side surface portion, it is possible to uniformly brighten the region that can be seen through from the inner slope, and to further uniform the light emission state of the inner slope.

According to the seventh aspect of the present invention, the transparent cover is fixedly held between the element support and the guide support, and each of the supports can be mounted on the circuit board. In the same environment as above, a test for detecting light of a predetermined wavelength can be performed in a state where the viewing angle is limited by the light guide member and the light is transmitted through the transmission cover. Therefore, it is possible to perform the permeability test without accompanying the test, and to reduce the work load of the test.

According to the eighth aspect of the present invention, since the infrared detection element is provided with a heat source and the heat source is heated to perform a test of the detection function by the infrared detection element, the abnormality of the element can be easily detected. Therefore, it is possible to effectively reduce the occurrence of detection failure.

(Overall configuration of flame detector)
A flame detector 10 according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of the flame detector 10, and FIG. 2 is an exploded perspective view.
The flame detector 10 is generally fixed and installed with the back side facing upward, and detects flames in the front front area (downward in the installed state) with the front face facing downward. The flame detector 10 is connected to a receiver (not shown) that centrally manages a plurality of flame detectors in a block that performs detection, and when a flame is detected, transmits a detection signal to the receiver.
In the following description, the direction of the flame detector 10 is defined as follows for convenience of description. That is, the direction along the direction from the front side to the back side of the flame detector 10 is defined as the X-axis direction. The flame detector 10 includes two main detection light-receiving elements 50 and 50 arranged in a certain direction orthogonal to the X-axis direction. In the following description, these main detection light-receiving elements 50 are provided. , 50 is referred to as the Y-axis direction. Further, a direction orthogonal to both the X-axis direction and the Y-axis direction is referred to as a Z-axis direction (see FIG. 1). In some cases, the front side of the flame detector 10 is referred to as “front side”, and the back side is referred to as “rear side”.

  The flame detector 10 is disposed inside the housing 20, the circuit board 30 disposed in the housing 20 and formed with a circuit for detecting flames, the main light source 11 connected to the circuit board 30, and the housing 20. It has a light emitting part 410 that emits light on the front surface, and is provided on the front side of the housing 20 and a light guide member 40 made of a translucent material that guides light from the main light source 11 to the light emitting part 410 by propagation inside. A main detection light-receiving element 50 that receives light having a predetermined wavelength emitted from the opening 214, a transmission cover 12 that is provided between the opening 214 and the main detection light-receiving element 50, and transmits light from the outside; A test light source 13 that projects test light onto the cover 12, a test light receiving element 14 that receives the test light transmitted through the transmission cover 12, and an element support 60 that fixes the orientation of the main detection light receiving element 50 with respect to the circuit board 30. Circuit board 3 And a guide support 70 that fixes the light guide member 40 with respect to.

(Casing)
The housing 20 includes a cover body 210 located on the most front side, a main body 220 that stores and holds the circuit board 30 and the like, and a base body 230 that is fixed to an installation location on the back side. It is formed of a white resin.
The base body 230 is formed in a circular dish shape centering on the X-axis direction, the back side thereof is fixedly installed upward at the installation location, and wiring is applied from the back side to be connected to the receiver described above. The

  The main body 220 has a rotating body shape that is substantially centered in the X-axis direction, that is, a bottomed cylindrical body having an outer diameter somewhat smaller than that of the base body 230, and the back surface of the bottom plate faces the base body 230. The base body 230 is attached so as to be fitted inside. On the back side of the bottom plate of the main body 220, a plurality of connection terminals (not shown) are provided, and the tip portions of the connection terminals are formed in a bowl shape. In other words, each connection terminal has a function of fixing the main body 220 to the base body 230 by engaging the hook-shaped portion with the engaged recess provided on the base body 230 side. Each connection terminal is connected to the circuit board 30 by wiring, and by engaging with the base body 230, power supply from the base body 230 side and transmission / reception of signals to / from the receiver are possible.

The cover body 210 is a rotating body that is substantially centered in the X-axis direction. It is comprised from the front end surface part 213 which continues to an edge part, and these are shape | molded integrally.
The outer diameter of the cylindrical portion 211 is set to be equal to the outer diameter of the base body 230, the rear side end is greatly opened, the main body 220 is fitted inside the opening end, and is connected by screwing. It is like that.

  The front end surface portion 213 is formed with an opening 214 having a large oval shape (a shape formed by connecting ends of a semicircular arc and a semicircular arc with a straight line) at the center thereof, and the longitudinal direction of the oval Is along the Y-axis direction. A circular black monitoring area confirmation mark 215 is attached around the opening 214. Inside the monitoring area confirmation mark 215, the main detection light receiving element 50 is disposed at the center of the opening 214 and on the rear rear side. An inner range of a straight line extending from the periphery of the main detection light receiving element 50 to each part along the inner edge of the monitoring area confirmation mark 215 is a viewing angle of the main detection light receiving element 50, that is, a monitoring range. 3A shows the mutual positional relationship when the main detection light receiving element 50 and the monitoring area confirmation mark 215 are viewed from the front of the flame detector 10, and FIG. 3B is inside the monitoring area from the front. FIG. 3C shows a mutual positional relationship when viewed from a position slightly shifted in the Y-axis direction, and FIG. 3C shows a mutual positional relationship when viewed from a position shifted further outside the monitoring area. As shown in these figures, the gap between the inner edge portion of the monitoring area confirmation mark 215 and the center portion of the element support 60 of the main detection light receiving element 50 described later gradually decreases from the monitoring area as the position deviates from the center position of the monitoring area. When it comes off, the gap is completely eliminated. That is, in a state where the flame detector 10 is installed on the ceiling or the like, it is possible to confirm whether or not the standing position is the monitoring area based on the presence or absence of a gap formed by the monitoring area confirmation mark 215. In the above example, the state shifted in the Y-axis direction is illustrated, but the same applies to the Z-axis direction or the combined direction of the Y-axis and the Z-axis.

  A storage space for storing the main components of the flame detector 10 is formed between the cover body 210 and the main body 220. In the storage space, as shown in FIG. 2, on the front side of the bottom plate of the main body 220, the circuit board 30, the board cover 33, the element support 60, the main detection light receiving element 50, the transmission cover 12, the guide support 70, the light The guide members 40 are mounted in order.

(Main detection light receiving element)
The main detection light receiving element 50 is an infrared sensor (for example, a pyroelectric element). Infrared light emitted from flames due to combustion has a characteristic that shows a peak that suddenly rises at a wavelength in the infrared region of 4.4 [μm] due to a phenomenon called CO ₂ resonance radiation, so an infrared sensor equipped with a filter that transmits light of that wavelength The main detection light-receiving element 50 and the main detection light-receiving element 50 including an infrared sensor equipped with a filter that transmits light having a wavelength of either one before or after (for example, 4.0 or 5.0 [μm]) are used. The flame is detected depending on whether the peak of [μm] can be detected. In each of the main detection light receiving elements 50 and 50, the lead wires of the elements are fixed to the circuit board 30 by soldering, and the two main detection light receiving elements 50 and 50 are close to each other along the Y-axis direction. In the state where they are arranged side by side, they are supported by an element support 60 described later with the detection surface facing the front side. Correspondingly, the front opening 214 of the cover body 210 described above is also formed in an oval shape along the Y-axis direction that can simultaneously surround two circles that are arranged in close proximity to each other.

  Each main detection light receiving element 50 includes a heating element (not shown) in the sensor, and the heating element is also connected to the circuit board 30. Such a heating element is used for self-diagnosis of the main detection light-receiving element 50. Control for executing the self-diagnosis is performed by the circuit board 30. When the diagnosis execution command is received from the receiver side, or when the diagnosis timing comes periodically by the built-in timer, the circuit board 30 energizes the heating element to generate heat. Then, the infrared rays generated thereby are detected by the main detection light receiving element 50. In the circuit board 30, depending on whether or not the infrared detection signal from the main detection light receiving element 50 at that time can obtain a predetermined intensity. Diagnose whether the device is functioning normally. If the abnormality is determined as a result of the diagnosis, the abnormality of the light receiving element 50 is transmitted to the receiver. In other words, the flame detector 50 can execute the self-diagnosis function of the main detection light receiving element 50 by the circuit board 30 and the heating element.

(Transparent cover)
The transmission cover 12 is a rectangular flat plate made of transparent sapphire glass that transmits infrared light disposed on the front side of the two main detection light receiving elements 50 and 50. The transmission cover 12 is provided to protect the light receiving surfaces and optical filters of the main detection light receiving elements 50 and 50 from being directly exposed to the outside so that they are not touched, soiled or damaged by human hands.

(Element support)
4 is an exploded perspective view showing the flame detection unit 100 having a configuration stored in the housing 20, FIG. 5 is a perspective view in which only the configuration stored in the housing 20 is assembled, and FIG. 7 is a sectional view taken along line U-U in FIG. 6, FIG. 8 is a sectional view taken along line V-V in FIG. 6, and FIG. 9 is taken along line W-W in FIG. FIG.
As shown in FIGS. 4 to 9, the element support 60 includes a substantially oval pedestal 61 along the Y-axis direction when viewed from the front, and four elements extending downward from the back surface of the pedestal 61 along the X-axis direction. Column 62 (one or two are not shown). The element support 60 is integrally formed of black resin.
The four support columns 62 are provided at the four corners of the pedestal 61. A boss 62 a having a smaller diameter than that of the support 62 is further extended from the front end surface of each support 62. The circuit board 30 has receiving holes 31 for the bosses 62a.

  The pedestal 61 is disposed along the YZ plane, and a recess is formed at the center thereof, and two element storage recesses 63 and 63 are formed along the Y-axis direction at the center of the recess. Each element storage recess 63 is formed in such a shape that the front side is open and a cylindrical body can be fitted in accordance with the element shape. Further, four through holes through which the leads of the main detection light receiving element 50 are inserted are formed at the bottom. With the element storage recess 63, the main detection light receiving element 50 is fixed in a direction suitable for flame detection in a state where the main detection light receiving element 50 faces the front side.

  In addition, a frame-shaped transmission cover holding portion 64 having a rectangular shape in front view is provided in the central recess of the pedestal 61 and in front of the element storage recesses 63, 63. Is formed with a back support portion 64 a which is an oval ridge that abuts from the back surface of the transmission cover 12. The transparent cover 12 is held by being fitted to the transparent cover holding portion 64, and is pressed and supported from the back by the back support portion 64a. Further, as will be described later, the element support 60 can be connected to the guide support 70 by its fitting structure. At the time of such connection, the element support 60 has the same size and the same shape as the back support portion 64a provided on the guide support 70 side. The front side of the transmission cover 12 is pressed and supported by the front support part (not shown). As a result, the transmission cover 12 is held in all directions without rattling.

  As shown in FIG. 7, a light source holding portion 65 that holds the test light source 13 is formed on the back side of the pedestal 61 so as to be adjacent to the element storage recesses 63 and 63. The light source holding part 65 is opened in the vicinity of the circuit board 30 in an oblique direction, and the test light source 13 mounted on the front side of the circuit board 30 holds the light source with its leads bent. It is inserted from the opening of the portion 65, and is held in a state in which the direction is fixed by being fitted inside. The light source holding part 65 penetrates from the opening part to the inside (back side) of the transmissive cover 12 in the element storing concave parts 63 and 63, and the transmissive cover 12 is passed through according to the holding angle of the test light source 13. The light can be transmitted and projected to the front side. The holding angle of the test light source 13 by the light source holding unit 65 will be described in detail later.

  Further, as shown in FIG. 8, the mounting arms 66 to the circuit board 30 hanging down toward the circuit board 30 are provided at diagonal positions sandwiching the element storage recesses 63, 63 on the back side of the base 61. Two 66 are formed. These mounting arms 66, 66 are plate-like members extending along the X-axis direction, and engaging projections 66a, 66a projecting in opposite directions are formed at the tip portions thereof. On the other hand, the circuit board 30 is formed with slit-like engagement holes 32 and 32 penetrating the plate surface, so that the tip portions of the mounting arms 66 and 66 can be mounted. That is, when the element support 60 is mounted on the circuit board 30, the tip ends of the mounting arms 66 and 66 are inserted into the engagement holes 32 and 32. At this time, the mounting arms 66 and 66 are inserted. Is bent in a direction opposite to the protruding direction of the engaging protrusions 66a, 66a. When the engaging protrusions 66a, 66a reach the back side of the circuit board 30, the mounting arms 66, 66 are restored by their elasticity. Thereby, the engagement protrusions 66a and 66a are locked to the edge portions of the engagement holes 32 and 32. At this time, since the engaging protrusions 66a and 66a protrude in opposite directions, an elastic force is exerted in a direction in which the engaging protrusions 66a and 66a are engaged with each other, and the engaging protrusions 66a are not removed unless the engaging protrusion 66a is manually operated in the backward direction. It is like that. At this time, since the end surfaces of the support columns 62 are in contact with the front surface of the circuit board 30, the play of the element support 60 is suppressed.

  Further, as shown in FIG. 7, the mounting arm to the guide support 70 raised toward the front of the front is provided at a diagonal position across the element storage recesses 63, 63 at the side edge portion of the front surface of the base 61. Two 67 are formed on one side and one on the other side. Each of the mounting arms 67 is a plate-like body extending along the X-axis direction, and an engagement protrusion 67a protruding in a direction facing each other is formed at the tip portion. On the other hand, the guide support 70 is formed with slit-like engagement holes 714 penetrating through the flat portion at three corresponding positions so that the tip portions of the mounting arms 67 can be mounted. That is, when the element support 60 and the guide support 70 are connected, the distal end portion of each mounting arm 67 is inserted into each engagement hole 714 from the back side of the guide support 70. The arm 67 bends in the direction opposite to the protruding direction of the engaging protrusion 67a. When the engaging protrusion 67a reaches the front side of the guide support 70, the mounting arm 67 returns to its elasticity. As a result, the engagement protrusion 67 a is locked to the edge of the engagement hole 714. At this time, the engaging protrusions 67a protrude in opposite directions, so that an elastic force acts in the direction in which the engaging protrusions 67a are engaged with each other, so that the engaging protrusions 67a are not pulled out unless the engaging protrusions 67a are manually operated in the backward direction. It has become. At this time, the upper surface of the pedestal 61 of the element support 60 and the back surface of the guide support 70 are in close contact with each other, so that the backlash between the supports 60 and 70 is suppressed.

(Main light source)
The main light source 11 is an LED fixedly mounted on the circuit board 30 so as to emit light toward the front front, and two main light sources 11 are provided. The main light source 11 is used for various purposes. For example, when a fire is detected, the light is turned off, and when a flame is detected, the light is turned on. When a plurality of flame detectors 10 are connected to a receiver, a response request for one of them is issued. If there is, the main light source of the flame detector 10 that is the subject of the response is switched to a blinking state and responds.

(Light guide member)
FIG. 10 is a perspective view showing the entire light guide member 40, FIG. 11 is a front view of the light guide member 40, and FIG. 12 is a partially enlarged view of the light guide member 40.
The light guide member 40 is fixedly held inside the housing 20 by a guide support 70 described later. Therefore, regarding the relative positional relationship between each part of the light guide member 40 described below and other components other than the light guide member 40, the light guide member 40 is fixed at a fixed position via the guide support 70. Is assumed.

  The light guide member 40 has an oval shape that is substantially circular in a front view, and has a first and second inner inclined surfaces 411 and 412 as light emitting surfaces that emit light on the front surface of the housing 20, and Two first light guides 420 extending outward from the light emitting part 410 and the first light guides 420 are vertically suspended from the first light guides 420 toward the circuit board 30 along the X-axis direction. Two second light guide portions 430 and a third light guide portion 440 for guiding the test light emitted from the test light source 13 to the test light receiving element 14, which are translucent. It is integrally molded with a certain resin. That is, the light guide member 40 can propagate light inside thereof.

The light emitting portion 410 is formed in an oval shape similar to the opening 214 of the cover body 211 of the casing 20 described above, and the light emitting portion 410 has a first shape of the light emitting portion 410 from the opening 214. It arrange | positions so that the 1st and 2nd inner slope 411,412 may face the exterior.
The two first light guides 420 are formed so as to protrude outward at diagonal positions on the outer peripheral surface (outer edge) of the elliptical light emitting part 410. Each of the first light guide unit 420 and the light emitting unit 410 is connected on the same plane along the YZ plane on the back surface. Then, on the back surfaces of the light emitting unit 410 and the first light guide unit 420, a member structure unit (illustrated by hidden lines in FIG. 10) is formed over numerous areas. The fine structure portion has the effect of reflecting the light toward the back side by the unevenness and emitting the light from the first and second inner inclined surfaces 411 and 412 as the light emitting surfaces on the front side.

In addition, each first light guide unit 420 is formed in a plate shape having a uniform thickness in the X-axis direction, and a columnar second light guide unit 430 is arranged in the X-axis direction on the back side. It is formed in a drooping state along.
Each of the second light guides 430 has a smooth end surface on the back side along the YZ plane, and is close to the main light source 11 mounted on the front surface of the circuit board 30 as shown in FIG. It is arranged in the state. That is, the end surface is an incident surface for the outgoing light of the main light source 11.

As shown in FIG. 12, a notch portion 421 having a V-shaped cross section is formed at a position of each first light guide portion 420 facing the front side end portion of the second light guide portion 430. . The notch 421 has an opening angle (inner angle) set to 92 °, and the notch 421 forms two opposing planes that are inclined at 46 ° with respect to the X-axis direction. By these two opposing surfaces, the light traveling in the second light guide 430 can be reflected almost in parallel to the flat surface of the first light guide 420 on both sides of the second light guide 430. It can be done.
As described above, the opening angle (inner angle) of the cutout portion 421 is set to 92 °, and the two planes are symmetric with respect to the direction along the second light guide portion 430. The light is reflected in a direction slightly toward the back side from the flat plate surface of the first light guide unit 420. And since the fine structure part mentioned above is formed in the back surface of the 1st light guide part 420, and the back surface of the light emission part 410, the 1st light guide part 420 and the light emission from the 2nd light guide part 430. The first and second inner slopes 411 and 412 can effectively emit light by being effectively reflected to the front side in the process of being propagated to the portion 410. The opening angle of the notch 421 is preferably 92 ° from the balance with transmitting light farther from the second light guide 430, but even if it is in the range of 90 ° to 95 °. good.

  Further, each first light guide unit 420 reflects the light reflected in two directions by the notch portion 421 in the X-axis direction so as to reflect the elliptical tangent direction of the light emitting unit 410 in the front view. Two parallel reflecting surfaces 422 and 423 are provided. By such reflecting surfaces 422 and 423, the reflected light travels along the oval shape of the light emitting portion 410 in a front view, and the light reaches farther, so that the entire light emitting portion 410 can emit light effectively. It has become.

  In addition, each of the first light guides 420 and the second light guides 430 is disposed so as to be covered by the cover body 210 of the housing 20 so that it cannot be seen from the opening 214. ing. Due to the joint structure of the first light guide unit 420 and the second light guide unit 430, light may pass through the first light guide unit 420 as it goes straight through the second light guide unit 430. However, since these light guides 420 and 430 are covered with the cover body 210, uneven light emission such as the light guide member 40 partially brightened by the transmitted light when viewed from the outside can be avoided. .

The light emitting portion 410 has an approximately circular shape that is an oval with a large opening at the center, and a cross-sectional shape formed by cutting a part of the annular shape is a mountain shape that protrudes forward in the front. That is, in the light emitting portion 410, a portion 413 corresponding to the mountain-shaped ridge is continuous along an ellipse. A first inner slope 411 is formed over the entire circumference just inside the ridge 413, and a second inner slope 412 is formed over the entire circumference. Further, an outer slope 414 is formed on the outer side of the ridge 413 over the entire circumference.
The ridge portion 413 of the light guide member 40 has the same size as the inner edge portion of the opening 214 of the cover body 210 of the housing 20, and the light guide member 40 is disposed so that the ridge portion 413 matches the opening 214. The Accordingly, only the first inner slope 411 and the second inner slope 412 are visible from the opening 214, and the outer slope 414 is not visible.

The first inner inclined surface 411 is inclined so as to generate a downward gradient toward the main detection light receiving elements 50 and 50, and the downward gradient is formed over the entire circumference. The inner slope 411 forms an oval mortar shape as a whole. Similarly, the second inner slope 412 inside the first inner slope 411 also forms a mortar shape. However, as shown in FIG. 8, the descending slope of the second inner slope 412 is steeper than the descending slope of the first inner slope 411.
That is, the first inner inclined surface 411 is arranged to limit the viewing angle with respect to each main detection light receiving element 50 located at the inner center thereof. The main detection light receiving element 50 used in the flame detector 10 has a viewing angle of 50 ° in all directions with respect to the center line direction (arranged along the X-axis direction). Is desirable. That is, within this viewing angle range, it is possible to maintain substantially uniform infrared detection accuracy in all directions. Accordingly, the first inner slope 411 is set so that the inclination angle with respect to the X-axis direction is 50 ° over the entire circumference. The first inner inclined surface 411 has a cone whose tip angle with respect to the center line is 50 ° inverted with respect to each of the main detection light receiving elements 50, 50, and the vertex of each of the main detection light receiving elements 50, 50 is inverted. The position is set so as to come into surface contact with the respective conical surfaces when arranged so as to be positioned. Therefore, the first inner inclined surface 411 realizes the viewing angle limiting function of each of the main detection light receiving elements 50 and 50.

On the other hand, since the second inner inclined surface 412 is steeper than the first inner inclined surface 411, the second inner inclined surface 412 is outside the range of the viewing angle of each of the main detection light receiving elements 50 and 50. The second inner inclined surface 412 is a test light incident portion 416 from the test light source 13 described above in a part of the entire circumference. That is, the direction of the test light source 13 is held by the element support 60 so that the test light is emitted toward the incident portion 416 that is a predetermined position of the second inner inclined surface 412. On the other hand, the inclination angle of the second inner slope 412 is uniformly set equal to that of the incident portion 416. The inclination angle of the incident portion 416 is an angle at which the test light from the test light source 13 does not reflect, and the optical axis direction of the test light from the test light source 13 that is inclined with respect to the Z-axis direction is the incident portion 416. The tilt angle is set so as to be parallel to the Z-axis direction due to refraction by.
In addition, only the incident part 416 may be set to an inclination angle that satisfies the above condition, and the entire area of the second inner slope 412 except for the incident part 416 may be set to a different inclination angle. A concave portion is formed on the inner slope at the boundary with the portion, so that dirt is likely to accumulate and it is difficult to remove the dirt. For this reason, the entire circumference of the second inner inclined surface 412 is set to an inclination angle equal to the incident angle 416 so that no recess is formed.

In addition, the first and second inner slopes 411 and 412 are subjected to a graining process as a process for suppressing reflection on the surfaces thereof. As described above, the first inner inclined surface 411 has a function of limiting the viewing angle of each main detection light receiving element 50. The viewing angle restriction is performed in order to restrict the main detection light receiving element 50 to a range in which a predetermined detection accuracy can be maintained in all directions around the optical axis on the front side. If the second inner inclined surfaces 411 and 412 are likely to be reflected, the light reflected by these inner inclined surfaces 411 and 412 is incident on the light receiving surface, and the detection accuracy varies in each direction. Therefore, the first and second inner slopes 411 and 412 are subjected to a texture process to suppress variations in detection accuracy in all directions.
Note that the test light incident portion 416 described above is maintained in a transparent state without being subjected to texturing only to ensure the test detection accuracy.

As described above, since the light emitting portion 410 is arranged so that the ridge portion 413 coincides with the inner edge portion of the opening portion 214 of the cover body 210, only the first and second inner inclined surfaces 411 and 412 are opened. The unit 214 emits light to the outside.
When the case where the first and second inner slopes 411 and 412 of the annular body are caused to emit light and the case where the outer slope 414 is caused to emit light are compared, as shown in FIG. Within the viewing angle range S of the element 50, there are regions where the outer slope 414 on one side is not visible, such as B1 and B2 indicated by diagonal lines, and the regions where these regions B1 and B2 overlap are outside of both sides. None of the slopes 414 can be seen.
However, when the first and second inner inclined surfaces 411 and 412 are caused to emit light as in the flame detector 10, such vision does not occur within the viewing angle range S.
That is, the display light can be more reliably recognized by a person in the monitoring area of the flame detector 10 and the visibility can be improved.
Further, visibility can be ensured even from an area (S ′, S ′ in FIG. 13) other than the monitoring area (S in FIG. 13), and the light emission state is viewed from almost all directions centering on the main detection light receiving element. be able to.

By the way, the light guide member 40 is formed by casting a transparent resin into a mold and is integrally formed. In this case, the light guide member 40 is generally easier to form when the thickness of each part is reduced. That is, in view of the advantage of molding, as shown in FIG. 14A, it is desirable that the outside of the ridge portion 413 of the light emitting portion 410 is provided with a step 414X to have a thin structure. However, in that case, when the light emission state is observed from each of the inner slopes 411 and 412, as shown in the figure, the step 414X blocks the scattered light on the back side provided with the fine structure portion, and the step portion blocking the back is The light emission state becomes dark (region d in FIG. 14A).
On the other hand, when the outer slope 414 is provided outside the ridge part 413 of the light emitting part 410, the scattered light on the back side provided with the fine structure part is not hindered as shown in FIG. Can be secured.

  However, when the outer slope 414 is formed on the outer peripheral side of the light emitting portion 410 as shown in FIG. 14B, the inner slopes 411 and 412 transmit from the inner slope 411 and 412 to the outer side end face 415 depending on the viewing angle. May appear. Therefore, on the outer peripheral side end surface of the light emitting unit 410 (and the side end surfaces excluding the reflection surfaces 422 and 423 of the first light guide unit 420), a fine structure portion made of streak-like projections is formed as in the back surface portion. Yes. Thereby, even when the side end surface 415 appears to be transmitted from the inner inclined surfaces 411 and 412, the scattered light is generated in the same manner as the back surface, and the region indicated by reference sign e in FIG. 14A becomes darker than the back surface. Absent.

  In FIG. 10, reference numeral 45 shown on the side end surface 415 of the light emitting portion 410 is an engagement protrusion that fits into a recess on the guide support 70 side when the light guide member 40 is attached to the guide support 70 described later. It is.

The third light guide unit 440 is for guiding the test light incident from the test light incident unit 416 to the test light receiving element 14 on the circuit board 30, and extends from the incident unit 416 in the Z-axis direction. In the X-axis direction, and the first transmission unit 441 extending outward along the Z-axis direction from the light emitting unit 410 in the projected configuration along the Z-axis direction and the light traveling in the first transmission unit 441 in the Z-axis direction. And a second transmission portion 443 extending from the reflection surface 442 toward the circuit board 30 along the X-axis direction.
The first transmission part 441 is a columnar body having a square cross section and extending along the Z-axis direction, and the second transmission part 443 is a columnar body having a square cross section and extending along the X-axis direction. The reflection surface 442 is formed by a smooth surface obtained by inclining the YZ plane by 45 ° about the Y-axis direction at the intersection of the first transmission unit 441 and the second transmission unit 443.
Further, the rear end face of the second transmission portion 443 is set to face the circuit board test light receiving element 14 and extends to the circuit board 30 side so as to be close to each other. The extending tip of the second transmission portion 443 is formed on a flat surface perpendicular to the optical axis of the test light receiving element 14, and the flat surface serves as a test light emitting portion 444.

(Test light source and test light receiving element)
The test light source 13 is an LED, and the test light receiving element 14 is a photodiode. The wavelength light emitted from the test light source 13 is a light receiving band. Both of the test light source 13 and the test light receiving element 14 are directly connected to the circuit board 30 without a socket or the like.
Since both the test light source 13 and the test light receiving element 14 are arranged close to each other on the circuit board 30, the test light source 13 and the test light receiving element 14 are located on the back side of the transmission cover 12. Therefore, it is not necessary to arrange the test light source 13 and the test light receiving element 14 so as to face each other with the transmission cover 12 interposed therebetween.

(Guide support)
As shown in FIGS. 4 and 7, the guide support 70 includes a substantially disc-shaped pedestal 71 disposed along the YZ plane inside the housing 2, and an outer peripheral edge of the pedestal 71 from the outer peripheral portion to the back side. And a peripheral wall portion 72 raised upward. The side wall 72 has a cylindrical shape, and the inner diameter thereof is set to be slightly larger than the outer diameter of the pedestal 61 of the element support 60. The guide supports 70 are connected to each other while the element support 60 is accommodated therein. It is possible.

An oval recess 711 is formed at the front center of the pedestal 71, and an oval opening 712 is formed at the bottom of the recess 711. The opening 712 communicates with each main detection light receiving element 50.
On the front side of the pedestal 71, a fitting portion 713 corresponding to the front view shape of the light guide member 40 is formed. The fitting portion 713 is formed by a ridge standing on the front surface of the pedestal 71, and is fixed by fitting the light guide member 40 into a region surrounded by the fitting portion 713 of the ridge. can do. In addition, a concave portion (not shown) into which the engaging protrusion 45 of the light guide member 40 is fitted is formed inside the fitting portion 713, whereby the light guide member 40 is fixed. Further, as shown in FIG. 4, locking projections 713 a that protrude toward the opening 712 are formed at two positions inside the fitting part 713 with the opening 712 interposed therebetween. The backlash of the light guide member 40 is suppressed.

Then, in a state where the light guide member 40 is fixed to the fitting portion 713, the concave portion 711 includes inner slopes 711a and 711b that form a substantially mortar shape as a whole together with the two inner slopes 411 and 412 of the light guide member 40. I have. One inner inclined surface 711b on the main detection light receiving element 50 side forms a substantially conical surface identical to the first inner inclined surface 411 of the light guide member 40 described above. Further, the other inner inclined surface 711a is set to have a gentler inclination than the one inner inclined surface 711b, so as not to interfere with the viewing angle defined by the first inner inclined surface 411 and the inner inclined surface 711b of the light guide member 40. It has become.
Further, the inner peripheral edge of the second inner inclined surface 412 of the light guide member 40 and the outer peripheral edge of the inner inclined surface 711a of the recess 711 are set to have the same size and the same shape as an ellipse. Although these inner slopes 412 and 711a have different inclination angles, by matching the dimensions as described above, it is possible to eliminate a step between them, and it is difficult for dirt to accumulate, and cleaning and removal thereof are also easy. .
Further, a front support portion (not shown) provided corresponding to the back support portion 64a of the element support 60 described above is formed immediately behind the opening 712 of the recess 711, and the element support 60 and the guide are provided. By connecting the support 70, the transmission cover 12 can be sandwiched between these support portions.

  As shown in FIGS. 2 and 7, slit-like engagement holes 714 into which the tip ends of the three mounting arms 67 of the element support 60 are inserted are formed at diagonal positions across the opening 712 of the base 711. It is installed. When connecting the guide support 70 and the element support 60, the base 61 of the element support 60 is inserted into the peripheral wall 72 of the guide support 70 from the back side, and each mounting arm 67 is inserted into the engagement hole 714. This is done by locking each engagement protrusion 67a to the front side of the engagement hole 714.

On the back surface of the base 71, two cylindrical structures 715 into which the two second light guide portions 430 of the light guide member 40 are inserted, and a quadrangular shape into which the second transmission portion 443 of the light guide member 40 is inserted. A cylindrical structure 716 extends toward the circuit board 30 side.
In the light guide member 40, the surfaces of the second light guide portions 430 and the second transmission portion 443 (excluding the end surface portions) are covered with the cylindrical structures 715 and 716 made of white resin. In this case, it is possible to reflect the light which is transmitted from the surface to the outside of the light guide member 40 inside.
Further, all the back surfaces of the light guide member 40 are in contact with the front surface of the base 71, and all side end surfaces of the light guide member 40 are in contact with the fitting portion 713. For this reason, the light which is going to permeate | transmit the light guide member 40 from the back surface and side end surface of the light guide member 40 can be reflected inside.
In the state where the guide support 70 is incorporated in the housing, the outer inclined surface 414 of the light guide member 40 and the front surface of the first light guide unit 420 are both the inner surface of the cover body 210 of the housing 20. An internal shape is formed so as to contact.
That is, the light guide member 40 can propagate the light from the main light source 11 to the inner inclined surfaces 411 and 412 without escaping to the outside, and can efficiently emit light.
Similarly, the light guide member 40 can efficiently propagate the light from the test light source 13 to the test light receiving element 14.

  As shown in FIG. 4, a protruding portion 721 (one not shown) extending in the four directions toward the radially outer side is formed on the rear side end of the peripheral wall portion 72. Each of the overhang portions 721 is adapted to fit into a recess (not shown) formed on the back side of the cover body 210 of the housing 20. Thereby, it is possible to improve the backlash in the rotation direction of the guide support 70, the element support 60 connected thereto, and the main detection light receiving elements 50.

(Circuit board)
On the circuit board 30, the main light source 11, the test light source 13, and the test light receiving element 14 described above are mounted near the plate surface, and the main detection light receiving elements 50 and 50 are mounted via an element support.
Furthermore, various electronic components and a microcomputer for causing the flame detector 10 to execute a predetermined operation are mounted on the circuit board 30.
The main processing by the circuit board 30 will be described below.
First, the circuit board 30 performs a flame detection process. In such processing, infrared detection of two wavelengths (for example, 4.0 [μm] and 4.4 [μm]) is periodically performed by each main detection light receiving element 50, and the detection intensity of each light receiving element 50, 50 is obtained. Then, when it is determined that the detection intensity of each wavelength is within a set value range that is an intensity specific to flame combustion, the circuit board 30 outputs a detection signal to the receiver. Then, when it is determined that the flame is detected by the receiver and a notification signal is transmitted, the circuit board 30 switches the two main light sources 11 that have been turned off until then to the lighting state, and blinks to emit light. The occurrence of flame is notified around the flame detector 10.

  In addition, the circuit board 30 executes a process for performing a permeability test for detecting dirt on the transmission cover 12. In this process, for example, the test light source 13 is periodically emitted, and it is determined whether the detection intensity of the test light by the test light receiving element 14 is equal to or higher than a threshold value set for stain determination. If it is less than the threshold value, a signal for detecting the contamination of the transparent cover 12 is output to the receiver.

  Further, the circuit board 30 executes a self-diagnosis process for determining whether or not the main detection light receiving elements 50 and 50 are normal. In such processing, for example, the heating element incorporated in each main detection light receiving element 50 is periodically heated, and whether the detection intensity of the pyroelectric element of each main detection light receiving element 50 is equal to or higher than a threshold value for abnormality determination. Make a decision. When any of the main detection light receiving elements is less than the threshold value, an abnormality occurrence signal of the main detection light receiving element is output to the receiver. With this processing, the circuit board 30 functions as a self-diagnosis control unit.

(Operational effect of embodiment of invention)
In the flame detector 10 having the above-described configuration, the light guide member 40 includes the ellipse-shaped light emitting portion 410, so that the light emission state can be visually recognized from all directions and the light emitting portion does not need to protrude, so that the X axis It is possible to reduce the size of the flame detector in the direction.
Further, the first inner inclined surface 411 of the light guide member 40 has a function of limiting the viewing angle of each main detection light receiving element 50. That is, by defining the viewing angle of the main detection light receiving element 50, it is possible to satisfy the detection accuracy planned for all directions, and to suppress the occurrence of variations in accuracy in each direction.
Further, the light guide member 40 includes a test light incident portion 416 and a third light guide portion 440, and propagates the test light received in front of the transmission cover 12 to the rear of the transmission cover 12. Both the test light source 13 and the test light-receiving element 14 can be directly mounted, and a member or structure for disposing either one in front of the transmission cover 12 is not required, and the number of parts can be reduced from this point. It is possible to plan.
Further, as described above, the light guide member 40 realizes the light emission state confirmation function from all directions, the viewing angle restriction function of the main detection light receiving element 50, and the test light propagation function all with one member. Therefore, effective reduction of the number of parts is realized also from this viewpoint.

Further, since the light guide member 40 emits light from the inner inclined surfaces 411 and 412 of the light emitting portion 410 to the outside of the housing, the field of view of the main detection light receiving element 50 is emitted as in the case of emitting light from the outer inclined surface. It is possible to avoid problems such as areas where the light emission state is not visible within the corner range and areas where a part of the ring is not visible, and the annular light emission state can be confirmed from any position within the viewing angle range. Thus, it is possible to improve the visibility.
Further, visibility can be ensured even from an area (S ′, S ′ in FIG. 13) other than the monitoring area (S in FIG. 13), and the light emission state is viewed from almost all directions centering on the main detection light receiving element. be able to.

In addition, the light guide member 40 is provided with an outer slope 414 outside the first and second inner slopes 411 and 412 that emit light to the outside of the housing, and a fine structure is provided on the back and side end faces. The light emission state from the inner slopes 411 and 412 can be maintained uniformly, and good light emission can be performed.
Furthermore, in the light guide member 40, since the junction part of the 1st light guide part 420 and the 2nd light guide part 430 is the arrangement | positioning hidden inside by the cover body 210 of the housing | casing 20, rather than other parts. The joint that is bright and easily emits light can be hidden from the outside, and the entire light emitting unit 420 can emit light uniformly.
Further, the light guide member 40 is formed with a notch 421 having a V-shaped cross section at a position facing the front side end of the second light guide 430, and the opening angle is set to 92 °. Therefore, it is possible to propagate the light through the first light guide unit 420 to a farther distance in the light emitting unit 410, while inducing the generation of scattered light by the microstructure on the back surface, It becomes possible to emit light more uniformly and brighter.

In the flame detector 10, the light guide member 40 is held by the guide support 70, and the guide support 70 can be connected to the element support 60, and the element support 60 can be attached to the circuit board 30. Furthermore, the transmission cover 12 can be fixedly held between the element support 60 and the guide support 70. For this reason, as shown in FIG. 5, the structure of the light guide member 40, the guide support 70, the transmission cover 12, the main detection light receiving element 50, and the element support 60 can be assembled on the circuit board 30. 100. In the assembled state of the flame detection unit 100, the main detection light receiving element 50 can have the same light receiving environment as the completed state of the flame detector 10 (for example, the viewing angle is limited by the light guide member 40 and the light receiving member 40 receives light). External light is received through the transmissive cover 12).
Therefore, in the manufacturing process of the flame detector 10, the final operation test can be performed in the assembled state of FIG. 5, and the casing 20 can be disassembled even if a re-inspection is necessary depending on the inspection result. It becomes unnecessary, and it becomes possible to speed up the manufacturing process and improve productivity.

  In addition, the flame detector 10 is provided with a heat source in addition to the main detection light-receiving element 50 and can test the detection function of the main detection light-receiving element 50 by heating the heat source. Therefore, it is possible to effectively avoid the occurrence of detection failure.

(Other examples with UV detectors)
Note that the main detection light receiving element of the flame detector 10 is not limited to the one that performs infrared detection as described above. For example, as shown in FIG. 15, a main detection light receiving element 50A including an ultraviolet detection element is used. Also good.
In that case, the circuit board 30A needs to form a circuit capable of detecting a flame by the main detection light receiving element 50A made of an ultraviolet detection element. However, the fitting structure and the fixing structure in the housing 20 of the circuit board 30A are the same as those of the circuit board 30, and the main light sources 11 and 11 and the test light receiving element 14 are arranged in the same manner as the circuit board 30. Is desirable.
Further, the main detection light-receiving element 50A that performs ultraviolet detection performs single flame detection, and a vertically long tube is used while being laid along the Y-axis direction. Therefore, the element storage recess 63A of the element support 60A is used. Forms only one having a fitting structure into which the main detection light receiving element 50A can be inserted from the side. It is desirable that the structure and dimensions other than the element fitting recess 63A of the element support 60A and the connection structure (the column 62A and the like) with the circuit board 30A are designed to be equal to the element support 60.
Further, it is desirable that the transmission cover 12A be formed of a material that easily transmits ultraviolet rays, instead of sapphire glass.
As described above, the flame detector for detecting flames by ultraviolet rays is configured in the same manner as the flame detector 10 except that the main detection light receiving element 50A, the element support 60A, the circuit board 30A, and the transmission cover 12A are configured. Can be realized. Specifically, the housing 20, the light guide member 40, and the guide support 70 can be made common, and when producing both a flame detector that detects infrared rays and a flame detector that detects ultraviolet rays, those Productivity can be improved.

(Other)
The arrangement of the test light source 13 and the test light receiving element 14 in the flame detector 10 described above may be reversed. In that case, the test light from the test light source 13 is incident from the emission part 444 at the extending tip of the second transmission part 443 of the light guide member 40, is emitted from the incident part 416, and is transmitted through the transmission cover 12 to be tested. The light receiving element 14 receives light.
In this case, it is necessary to extend the leads somewhat from the circuit board 30 so that the test light receiving element 14 can be fitted to the element support 60. Further, it is necessary to modify the light source holding portion 65 of the element support 60 to an element holding portion having a structure in which the test light receiving element 14 can be fitted.

It is a perspective view of the flame detector which is embodiment of invention. It is a disassembled perspective view of a flame detector. FIG. 3A is a functional explanatory diagram of the monitoring area confirmation mark, and FIG. 3A shows the mutual positional relationship when the main detection light receiving element and the monitoring area confirmation mark are viewed from the front of the flame detector. Indicates the mutual positional relationship when viewed from a position slightly shifted in the Y-axis direction from the front in the monitoring area, and FIG. 3C shows the mutual relationship when viewed from a position further shifted out of the monitoring area. The positional relationship of is shown. It is the disassembled perspective view which showed the flame detection unit which consists of a structure stored in the inside of a housing | casing. It is the perspective view which assembled the flame detection unit. It is a top view of the structure of FIG. FIG. 7 is a cross-sectional view taken along the line U-U in FIG. 6. It is sectional drawing along the VV line of FIG. It is sectional drawing along the WW line of FIG. It is a perspective view which shows the whole light guide member. It is a front view of a light guide member. It is the elements on larger scale of a light guide member. It is explanatory drawing which shows the relationship between the visible range and the monitoring area | region when light-emitting the inner side slope of a light guide member. FIG. 14A shows the light emission state by the inner slope when the back slope is not formed on the light guide member, and FIG. 14B shows the light emission state by the inner slope when the back slope is formed on the light guide member. FIG. It is a disassembled perspective view of the flame detector at the time of using an ultraviolet detection element as a main detection light receiving element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Flame detector 11 Main light source 12 Transmission cover 13 Test light source 14 Test light receiving element 20 Case 214 Opening part 30 Circuit board 40 Light guide member 410 Light emission part 411 First inner slope 412 Second inner slope 414 Outer slope 416 Incident part 420 First light guide part 421 V-shaped notch 430 Second light guide part 444 Emitting part 50 Main detection light receiving element 60 Element support 70 Guide support 100 Flame detection unit

Claims (8)

A housing,
A circuit board disposed inside the housing and formed with a circuit required for detection of flame;
A main light source connected to the circuit board;
A light guide member having a light emitting portion that emits light in front of the housing, and made of a translucent material that guides light from the main light source to the light emitting portion by propagation inside thereof;
A main detection light-receiving element that receives light of a predetermined wavelength emitted by a flame from an opening provided on the front side of the housing;
A transmission cover that is provided between the opening and the main detection light-receiving element and transmits light from outside;
In a flame detector comprising:
A light emitting portion of the light guide member is formed in a substantially annular shape surrounding the main detection light receiving element on the front side of the housing to have a viewing angle limiting function for limiting the field of view of the main detection light receiving element to a predetermined range. With
A flame detector characterized by forming an inner slope inclined toward the main detection light-receiving element over the entire inner circumference of the substantially annular shape, and emitting light from the inner slope. The light guide member includes a first light guide portion extending outward from the substantially annular light emitting portion, and a second light portion extending from the first light guide portion to the main light source. A light guide,
The flame detector according to claim 1, wherein a joint portion between the first light guide portion and the second light guide portion is arranged to be hidden in the housing. The first light guide portion of the light guide member has a flat plate shape,
The light emitting portion and the first light guide portion are formed such that surfaces opposite to the light emitting surface are continuous on the same plane, and a plurality of fine grooves or fine protrusions are formed on the plane. The flame detector according to claim 2, wherein a fine structure portion is formed. The light that travels along the second light guide unit is positioned along the flat surface of the first light guide unit at a position facing the end of the second light guide unit of the first light guide unit. Provide a V-shaped notch that forms two reflective surfaces that reflect in the direction,
The flame detector according to claim 3, wherein an opening angle of the V-shaped notch is greater than 90 ° and not greater than 95 °.   5. The outer slope is formed over the outer circumference of the substantially annular shape so that the cross-sectional shape of the substantially annular portion of the light emitting portion of the light guide member is a mountain shape. Flame detector.   The flame detector according to any one of claims 3 to 5, wherein the fine structure portion is formed on an outer peripheral side surface portion of a substantially annular portion of the light emitting portion of the light guide member. An element support for fixing the main detection light-receiving element to the circuit board;
A guide support for fixing the light guide member to the circuit board;
The flame according to any one of claims 1 to 6 , wherein the transparent cover is fixedly sandwiched between the element support and the guide support, and each of the supports is fixed to the circuit board. sensor. The main detection light receiving element is an infrared detection element, and a heat source is attached to the infrared detection element,
The flame detector according to any one of claims 1 to 7 , further comprising a self-diagnosis control unit that heats the heat source and tests a detection function of the infrared detection element.

Images