JP3114130B2 - Flame fire detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-type fire detector for detecting a fire flame and detecting the occurrence of a fire, and more particularly, to a light-transmitting window of a housing through which light from the flame passes. It is related to the improvement of.

[0002]

2. Description of the Related Art A flame type fire detector uses, for example, a pyroelectric infrared detecting element (hereinafter referred to as a pyroelectric element) as a light receiving element, and detects light in a specific wavelength region of infrared light emitted from a fire flame. It detects the occurrence of a fire. The light-receiving element of such a fire detector is housed in a housing, and the light-receiving surface is disposed so as to face the light-transmitting window. The light-receiving element is vulnerable to environmental changes such as temperature and humidity, and its characteristics change if the light-receiving surface is contaminated with dust, oily smoke, etc., so the light-transmitting window is provided with a protective plate to protect the light-receiving element from the outside There is a need. The material of this protective plate is limited in order to transmit infrared rays having a wavelength specific to a fire, and sapphire is generally used.

Conventionally, a flame-type fire detector is manufactured by casting or pulling a metal material into a casing, and affixing a sapphire plate to the light-transmitting window through a packing, and using a holding metal made of a metal material. Although stopped, there were various problems such as being large, heavy, and expensive. Therefore, in recent years, in order to reduce the size and weight and reduce the cost, a case in which the housing is molded from a synthetic resin is generally used.

FIG. 5 is a sectional view showing an example of a conventional flame fire detector using a housing made of a synthetic resin. In the figure, reference numeral 30 denotes a housing, a cylindrical main body 31 having a bottom plate 32.
And the cover 3 connected to the main body 31 by the locking claw 34
The cover 33 is formed in a substantially Mt. Fuji shape by a cylindrical portion and an inclined portion connected to the main body 31, and a light transmitting window 36 is provided in a concave portion 35 provided on the upper surface. Reference numeral 37 denotes a protection plate made of sapphire which is fitted into the recess 35 and adhered and fixed to the cover 33 with an adhesive 38.

Reference numeral 39 denotes a printed circuit board on which electric components constituting an amplification circuit, a fire discrimination circuit, a switching circuit, and the like (not shown) are mounted. The printed circuit board is accommodated in the housing 30 and fixed to the bottom plate 32 by screws 40. I have. 41 is a light receiving element for receiving the infrared rays of the flame, the pyroelectric element is accommodated in the can, the light receiving section provided on the upper surface is sealed with a silicon plate, and mounted on the printed circuit board 39 via the cylindrical mount 43. The lead wire 42 is soldered to the printed circuit board 39. At this time, the light receiving portion of the light receiving element 41 is disposed so as to face the protective plate 37 and to be close to it.

[0006] The flame type fire detector as described above has a light transmitting window 3.
Since the protective plate 37 made of a sapphire plate is attached to 6, the light receiving element 41 is not touched from the outside, and the light receiving portion is not contaminated by dust, oily smoke, or the like, and the characteristics are not changed by a change in environment. . In addition, the protection plate 3
In the case of 7, a fixing member made of synthetic resin is fixed by screwing instead of bonding with an adhesive 38.

In the above flame type fire detector, a protective plate 37 made of a silicon plate for sealing the light receiving portion of the light receiving element 41 and a sapphire plate provided on the light transmitting window 36 of the housing 30 is used for detecting the flame. Since it does not transmit only the infrared light of the specific wavelength region required for the infrared ray, if infrared light other than the specific wavelength region enters the light receiving element 41, this is processed by an electric circuit,
Trying to prevent false alarms.

[0008] However, processing by an electric circuit becomes complicated, and processing may not be completed. In some cases, a false alarm may occur. Therefore, the light-transmitting window has a band-pass filter function so that the light-receiving element receives only infrared rays in a specific wavelength region. One provided with an optical filter has been put to practical use. This optical filter, for example, to form a filter surface by providing a coating layer that does not transmit infrared light having a specific wavelength or more on one surface of a sapphire plate, and to provide a coating layer that does not transmit infrared light having a specific wavelength or less on the other surface. A cut surface is formed. These coating layers are formed by vapor deposition or coating so as to transmit only infrared rays in a specific wavelength region.

[0009]

In the above-described conventional flame type fire detector, since the optical filter is provided on the surface of the transmission window of the housing so as to be exposed to the surface, dust and the like adhere to the fire filter. When this occurs, it becomes difficult to detect a fire flame, and if it is cleaned to remove this dirt, the coating layer will be damaged, and the detection wavelength range will be widened, causing a problem of causing false reports.

[0010] Such an optical filter is usually provided with a coating layer on both sides of a large-area translucent material (for example, sapphire) to form a filter surface and a cut surface, and cut this into a predetermined size. Since the end of the translucent body that has been manufactured or cut in advance to a predetermined size is supported by a holder and a coating layer is provided on both sides, the end (cut surface) is an untreated transparent body. Because the light is directly exposed to the end of the optical filter, the light only passes through either the filter surface or the cut surface. And may cause false information.

Further, it is desirable to increase the area of the optical filter as much as possible in order to widen the fire monitoring area. However, there is a contradictory problem that the larger the area, the higher the cost and the higher the cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a flame-type fire detector in which no dust or the like is attached and only light in a specific wavelength region is incident on a light receiving element. It is intended for.

[0013]

According to the flame type fire detector according to the present invention, a first concave portion is provided on an upper surface of a cover, and a second concave portion having a small diameter is provided at a bottom portion of the first concave portion. A doughnut-shaped packing having an outer diameter greater than the outer diameter of the optical filter and an inner diameter smaller than the outer diameter of the optical filter in the first recess; The protection plate is provided via the.

Further, a plurality of engaging means are provided on the outer periphery of the first concave portion of the cover, and the pressing means has a light transmitting hole having a diameter smaller than the outer diameter of the protection plate and has a plurality of locking pieces projecting therefrom. An optical filter, a packing, and a protective plate are fixed to a cover by locking a locking piece to an engaging means.

[0015]

According to the present invention, of the light incident from the protective plate, light other than the specific wavelength region is blocked by the optical filter, and only the light within the specific wavelength region is received by the light receiving element to detect the occurrence of a fire. At this time, since packing is interposed between the protective plate and the optical filter, there is no possibility that light may enter from the end of the optical filter.

The cover is connected to the main body to which the printed circuit board is fixed, and the optical filter, the packing, and the protective plate are fitted into the first and second concave portions formed around the light-transmitting window provided on the cover. Next, the retaining piece of the holding means is engaged with the engaging means provided on the outer periphery of the first recess, and the optical filter, the packing and the protection plate are fixed to the first and second recesses by the holding means. In this case, the cover to which the optical filter, the packing, and the protection plate are fixed in advance by the holding means may be coupled to the main body to which the printed circuit board is fixed.

[0017]

1 is a sectional view of an embodiment of the present invention, FIG. 2 is a plan view thereof, FIG. 3 is an exploded perspective view of a cover, and FIG. 4 is a sectional view and a bottom view of a main part. In the figure, reference numeral 1 denotes a housing, which is composed of a cylindrical main body 2 having a bottom plate 3 and a cover 4 connected to the main body 2 by a locking claw. It is composed of an inclined portion whose diameter is reduced upward from the joining portion and a bottomed cylindrical portion having a smaller diameter than the joining portion formed above the inclined portion, and a large diameter portion is provided at the center of the bottomed cylindrical portion. A first concave portion 5 and a second concave portion 6 having a smaller diameter than the concave portion 5 formed at the bottom thereof.
The second concave portion 6 is provided with a light transmitting window 7 having a smaller diameter.

Reference numerals 8a, 8b and 8c denote engaging portions provided on the bottomed cylindrical portion on the outer periphery of the first concave portion 5, projecting inward in a box shape and opening downward, and the upper portion is shown in FIG. As shown in FIG. 7, a part is opened, and the locking part 9 is formed by the remaining part.

Reference numeral 10 denotes an optical filter having an outer diameter substantially equal to the inner diameter d _{2 of} the second recess 6 and fitted in the second recess 6, for example, a filter surface is formed on one surface of a sapphire plate by coating. Then, a cut surface is formed on the other surface by coating. Reference numeral 11 denotes a protection plate having an outer diameter substantially equal to the inner diameter d1 of the _first recess 5 and fitted into the first recess 5 and is made of, for example, sapphire. Reference numeral 12 denotes an optical filter 1 in the first recess 5.
The outer diameter d ₅ is substantially equal to the inner diameter d ₁ of the first concave portion 5 and larger than the outer diameter d ₄ of the optical filter 10, and the inner diameter d ₆ is The optical filter 10 is formed smaller than the outer diameter d ₄ .

Reference numeral 13 denotes a press ring formed by molding a synthetic resin, and has an inner diameter d smaller than the outer diameter d ₇ of the protective plate 11 at the center.
_Eight window holes 14 are provided. On the lower side, locking pieces 15a, 15b, 15c having locking claws 16 and having elasticity protrude from the engaging portions 8a, 8b, 8c of the cover 4. Have been. Reference numeral 17 denotes an LED display window provided on the inclined portion of the cover 4, 18 denotes a plurality of fins formed at substantially equal intervals from the side wall of the cylindrical portion of the cover 4 to the inclined portion, and 19 denotes a protection member for the light receiving element 22. is there.

Reference numeral 20 denotes an electric circuit portion accommodated in the housing 1. Reference numeral 21 denotes a first printed circuit board having a light receiving element 22 mounted on an upper surface and a preamplifier portion (not shown) provided on a lower surface. This is a shield case that covers the preamplifier and the like. Reference numeral 24 denotes a second printed circuit board larger than the first printed circuit board 21 provided with a main amplifier section, a fire discriminating circuit section, and the like. Both printed circuit boards 21 and 24 are electrically connected by spacers 25 such as conductive connection pins. Mechanically and mechanically. Reference numeral 26 denotes a blade which is attached to the lower surface of the main body 2, is fixedly connected to a terminal 29 of a base 28 provided on a ceiling or the like, and is electrically connected to the second printed circuit board 2.
4 is fixed to the main body 2 by a conductive screw 27 and connected to the blade fitting 26. In addition, the first printed board 21 and the second printed board 24 are vertically connected by a spacer made of an insulating material, and the two printed boards 21 and 24 are connected.
May be connected by a lead wire or the like.

To assemble the flame type fire detector as described above, for example, an electric circuit in which a second printed circuit board 24 is connected to a first printed circuit board 21 on which a light receiving element 22 is mounted by a spacer 25 is provided. The part 20 is housed in the main body 2,
The second printed circuit board 24 is fixed to the main body 2 by screws 27. Next, the cover 4 is put on the main body 2 and the two are integrally connected. At this time, the light receiving element 22 is disposed at a predetermined position, that is, at a position facing the light transmitting window 14 and in close proximity thereto.

Next, the optical filter 10 is fitted into the second recess 6 of the cover 4. At this time, the thickness t of the optical filter 10 is substantially equal to or slightly greater than the depth h of the second concave portion 6, so that the upper surface of the optical filter 10 is substantially equal to the upper surface of the second concave portion 6. Coplanar or slightly projecting. Next, the packing 1 is inserted into the first recess 5.
2 and the protective plate 11 is fitted thereon.

Next, the locking pieces 15a to 15c are
Pressing ring 1 in alignment with engaging portions 8a to 8c of
3 is placed on the cover 4 and pressed down. As a result, the locking pieces 15a to 15c are fitted into the engaging portions 8a to 8c, respectively, and the locking claws 16 are locked to the locking portions 9 by their elasticity. As a result, the optical filter 10, the packing 1
2 and the protection plate 11 are provided with the first and second concave portions 5 of the cover 13.
6 is tightly held and fixed between the press ring 13 and the press ring 13. Note that the cover 4 on which the optical filter 10, the packing 12, and the protection plate 11 are mounted may be connected to the main body 4 to which the printed boards 21 and 24 are attached in advance by the holding ring 13.

As a result, the optical filter 10, the packing 12, and the protective plate 11 are mounted on the light transmitting window 7 of the cover 4, but the engaging portions 8a to 8c and the locking pieces 15 of the press ring 13 are provided.
a to 15c, water, dust and the like are prevented from entering from the gap, and the locking piece 15a is formed.
In order to firmly fix the fixing pieces 15a to 15c, the fitting portions 8a to 8c are filled with a filler 13a such as
a to 15c are fixed, and the optical filter 10, the packing 12, and the protective plate 11 are sealed.

As described above, the present invention provides the optical filter 10
Since the protective plate 11 is disposed on the front surface of the optical filter, dust and the like do not adhere to the optical filter and become dirty.
Even if cleaning is performed to remove the dirt, the optical filter 1
0 is not damaged. Also, the inner diameter d of the packing 12
₆ is formed to be smaller than the outer diameter d ₄ of the optical filter 10, and when assembled into the first and second concave portions 5 and 6 of the cover 4, the packing 12 covers the periphery of the upper surface of the optical filter 10. In addition, there is no possibility that light enters from the end of the optical filter 10.

In the above description, a case has been described in which light in a specific wavelength region of infrared light emitted from a fire flame is detected. However, a flame type sensing a fire by detecting light in a specific wavelength region of ultraviolet light emitted from a fire flame. The present invention can be applied to a fire detector. Further, in the above embodiment, the case where the present invention is applied to the flame type fire detector having the structure as shown in FIGS. 1 and 2 has been described, but the fire detector or the main body and the cover as shown in FIG. The present invention can also be applied to a fire detector or the like having a cylindrical housing having substantially the same diameter. Further, in the above embodiment, the case where the electric circuit unit is constituted by two printed boards is shown. However, the present invention is also applied to a flame and fire detector in which the electric circuit unit is constituted by one or three or more printed boards. Can be implemented.

In the above description, a case where a bandpass filter having a coating layer of a filter layer and a cut layer on both surfaces of a light-transmitting body (for example, sapphire) is used as an optical filter. An optical filter in which either one of a filter layer and a cut layer is provided on any surface may be used. In this case, by incorporating the coating layer toward the protective window plate, the coating layer can be completely protected. The material of the light transmitting body of the optical filter, the material of the filter layer and the cut layer, or the material of the protective plate may be selected from those suitable for the wavelength of light to be detected.

[0029]

As is apparent from the above description, according to the present invention, an optical filter is provided in close proximity to a light receiving section of a light receiving element.
Further, since the protective plate is provided on the front surface via the packing, the following remarkable effects can be obtained. (1) The surface of the optical filter is protected by a protective plate,
Since it is not directly exposed to the outside, dust and the like do not adhere and become dirty, and therefore, there is no danger of damaging the optical filter even if the dirt on the protective plate is cleaned. (2) Since the optical filter is arranged close to the light receiving element, the viewing angle does not become narrow even if an optical filter having a small diameter is used. Therefore, a small optical filter can be used, and the cost can be reduced.

(3) Since a packing whose outer diameter is larger than the outer diameter of the optical filter and whose inner diameter is smaller than the outer diameter of the optical filter is interposed between the optical filter and the protective plate, light from the end of the optical filter is Can be prevented from entering. For this reason, it is possible to prevent the occurrence of a false report due to the incidence of light having a wavelength other than the specific wavelength region. (4) The use of the packing can prevent water and dust from entering between the protective plate and the optical filter.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is an exploded perspective view of the cover of FIG. 1;

FIG. 4A is an enlarged sectional view of a main part of FIG. (B) It is a bottom view of a figure.

FIG. 5 is a longitudinal sectional view of an example of a conventional flame fire detector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Main body 3 Bottom plate 4 Cover 5 1st recessed part 6 2nd recessed part 7 Transparent window 8a, 8b, 8c Engagement part 10 Optical filter 11 Protective plate 12 Packing 13 Pressing ring 15a, 15b, 15c Locking piece DESCRIPTION OF SYMBOLS 16 Engagement claw 20 Electric circuit part 21 First printed board 22 Light receiving element 24 Second printed board

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G08B 17/00-17/12 G01J 1/00-1/60 G01J 11/00 G02B 5/20-5/28 H04L 27 / 14 H04L 29/76

Claims (2)

(57) [Claims] 1. A housing comprising a main body, a cover having a light-transmitting window on an upper surface, and coupled to the main body, and a protection made of a material that transmits light emitted from a flame and attached to the light-transmitting window of the cover. In a flame type fire detector comprising a plate and a printed circuit board on which a light receiving element is mounted and an electric circuit portion is provided and housed in the housing, a first concave portion is provided on an upper surface of the cover, First
A second concave portion having a smaller diameter than the first concave portion is provided at a bottom portion of the concave portion, and a light-transmitting window is provided at the bottom portion; an optical filter is disposed at the second concave portion; A flame type fire detector, wherein a protective plate is provided via a donut-shaped packing having an inner diameter larger than the outer diameter of the optical filter and smaller than the outer diameter of the optical filter. 2. A pressing means having a plurality of engaging means provided on the outer periphery of a first concave portion of a cover, having a light-transmitting hole having a diameter smaller than the outer diameter of the protection plate, and having a plurality of locking pieces projected therefrom. The flame type fire detector according to claim 1, wherein a locking piece is locked to the engaging means, and the optical filter, the packing, and the protection plate are fixed to the cover.