JP2709661B2 - Radiant 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 radiant fire detector which is installed in, for example, a tunnel, a cave, or the like, and detects a fire by detecting a fire flame.

[0002]

2. Description of the Related Art A radiant fire detector uses, for example, a pyroelectric infrared detecting element (hereinafter referred to as a pyroelectric element) as a detector, and detects infrared rays emitted from a fire flame to detect the occurrence of a fire. Things.

FIG. 7 is a sectional view showing an example of a conventional radiant fire detector. In the drawing, reference numeral 60 denotes a housing, and a bottom plate 62
And a cover 63 connected to the main body 61 by a locking claw 64. The cover 63 is formed in a substantially Mt. Fuji shape by a cylindrical portion and an inclined portion connected to the main body 61. Is provided with a light transmitting window 65.

[0006] Reference numeral 66 denotes a printed circuit board on which electric parts constituting an amplification circuit, a fire discrimination circuit, a switching circuit, and the like (not shown) are mounted. . Reference numeral 68 denotes a light receiving element such as a pyroelectric element for receiving and detecting the light of the flame.
The printed circuit board 66 is mounted on the printed circuit board 66 via a wire 0. At this time, the light receiving element 68 is connected to the light transmitting window 65 of the cover 63.
, And is disposed at a position close to and adjacent to.

In the conventional radiation fire detector as described above, it is difficult to reduce the size of the printed circuit board 66 because the printed circuit board 66 has a large number of electric components constituting an amplifier circuit and the like as described above. Therefore, even if the light receiving element 68 is to be brought close to the light transmitting window 65, the printed circuit board 66 is
Since it cannot be accommodated above the zero, that is, in the inclined portion of the cover 63, it is disposed in the cylindrical main body 61. Therefore, in order to bring the light receiving element 68 close to the transmission window 65,
The light receiving element 68 is connected to the printed circuit board via the long lead wire 69, or the mount 70 supports the light receiving element 68, and the lead wire 69 is connected to the printed circuit board 66 so that the light receiving element 68 is opposed to the light transmitting window 65 and close to the light transmitting window 65. ing.

[0006]

However, the above-mentioned conventional radiant fire detector has the following problems.

(1) Since the lead wire 69 of the light receiving element 68 becomes long, it acts as an antenna and picks up electromagnetic waves to easily cause a malfunction.

(2) When the light-receiving element 68 is supported only by the lead wire 69, the lead wire 69 is bent by an impact or the like, and the position of the light-receiving element 68 is displaced.

(3) When a pyroelectric element for detecting infrared rays is used as the light receiving element 68, the pyroelectric element is mounted on a mount 70.
If the sensor is vibrated even if it is supported, the pyroelectric element will move greatly, and this movement may produce an output even though the pyroelectric element has not detected a flame, and this output causes a malfunction.

The present invention has been made in order to solve the above-mentioned problems, and there is no fear that the light receiving element is moved or the lead wire is bent due to shock or vibration, and furthermore, there is no possibility of being affected by electromagnetic waves. It is intended to obtain a fire detector.

[0011]

SUMMARY OF THE INVENTION A radiant fire detector according to the present invention has a bottomed cylindrical main body and an inclined portion connected to the main body and reduced in diameter toward the upper side. A housing including a cover provided with a light transmitting window through which light emitted from the flame is transmitted; and a small first housing housed in an inclined portion of the housing.
A second printed circuit board larger than the first printed circuit board, which is coupled to the lower side of the first printed circuit board via the printed circuit board and the spacer, and is accommodated in the housing; A light-receiving element disposed between the window and the first printed circuit board, mounted on the first printed circuit board and connected to detect light from a fire flame transmitted through the light-transmitting window;
A first circuit unit having a preamplifier unit for amplifying at least an output signal of the light receiving element is provided on the first printed circuit board, and the first circuit unit of the sensor is provided on the second printed circuit board.
A second circuit unit is provided except for the circuit unit of FIG.

In the above-mentioned radiant fire detector,
The cover has a cylindrical portion having a smaller diameter than the lower portion and a light transmitting portion provided on the upper bottom at an upper portion of the inclined portion of the housing, and a plurality of fins provided at substantially equal intervals from the side wall to the inclined portion of the cylindrical portion. It is a thing.

[0013]

A first printed circuit board provided with a light receiving element, a preamplifier section, etc., and a second printed circuit board provided with a main amplifier section, a fire discrimination section, etc. are vertically interposed by spacers.
Since it is arranged in a step, it can be easily accommodated in a substantially Mt. Fuji-shaped housing whose upper part is narrowed, thereby shortening the length of the lead wire from the light receiving element to the first printed circuit board, Alternatively, the light receiving element can be directly fixed to the first printed circuit board. Further, since the preamplifier is provided on the first printed circuit board on which the light receiving element is mounted, the distance between the light receiving element and the preamplifier can be minimized.

Further, when attaching / detaching the sensor to / from the base,
An attachment / detachment jig is engaged with a plurality of fins provided on the case and rotated.

[0015]

1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a plan view thereof. In both figures, reference numeral 10 denotes a housing, which comprises a cylindrical main body 11 having a bottom plate 12 and a cover 13 connected to the main body 11 by locking claws.
1 and a cylindrical portion having a smaller diameter than the connecting portion formed above the inclined portion and an inclined portion reduced in diameter upward from the connecting portion. A light transmitting window 14 is provided. Reference numeral 15 denotes a plurality of filling portions projecting around the light transmitting window 14 and opening downward.

Reference numeral 16 denotes a window plate made of sapphire as an infrared filter disposed on the light- transmitting window 14 via a packing 17. Reference numeral 18 denotes a locking claw that is locked to the filling portion 15.
The press ring 6 is fixed to the translucent window 14, and the filling portion 15 is charged with a filling material 19 such as silicone rubber for waterproofing. Reference numeral 20 denotes an LED display window provided on the inclined portion of the cover 13, and reference numeral 21 denotes a plurality of fins formed at substantially equal intervals from the side wall of the cylindrical portion of the cover 13 to the inclined portion.

Reference numeral 30 denotes an electric circuit section housed in the housing 10, and an outline of the circuit is shown in FIG. 33 is a light receiving element, 4
1 is a preamplifier section having one or more stages of OP amplifiers,
Reference numeral 42 denotes an output resistor, which forms the first circuit section 40. Reference numeral 44 denotes a main amplifier section having an OP amplifier and a sensitivity adjustment function; 45, a level discriminating section having an OP amp for comparison; and 46 and 47, integrating circuits for delay; Integration circuits 46, 4
7, the transistor 48, and the Zener diode 49 constitute a fire determination unit. Reference numeral 50 denotes a switching element for outputting a fire signal, 51 and 52 denote constant voltage circuits, 53 denotes a diode bridge for depolarizing, and 54 denotes an output terminal. The unit 40 and the second circuit unit 43 are connected by a conductor 37a.

FIGS. 4 and 5 are a plan view and a side view of a printed circuit board incorporating the above-described electric circuit. 31 is a small first printed circuit board on which the first circuit section 40 is provided, 32
Denotes a preamplifier unit 4 provided on the first printed circuit board 31
This is a shield case that covers the circuit components that constitute 1 and the like.
33 is mounted on the upper surface of the first printed circuit board 31, and the lead wire inserted into the through hole is connected to the first printed circuit board 3.
1 is a light receiving element such as a pyroelectric element connected to a printed wiring on the lower surface of the light emitting element 1.

Reference numeral 35 denotes a first circuit provided with the second circuit section 43.
2nd printed circuit board larger than printed circuit board 31 of 3
Reference numeral 6 denotes an operation indicator such as an LED mounted on the second printed circuit board 35, and the two printed boards 31, 35 are electrically connected by a spacer 37 such as a conductive connection pin.

Reference numeral 38 denotes a metal blade provided on the lower surface of the main body 31, fixedly connected to a terminal of a base provided on a ceiling or the like, and electrically connected thereto. While being fixed to the main body 11 by the screw 39,
It is connected to the blade fitting 38. Note that the first printed board 31 and the second printed board 35 may be vertically connected by a spacer made of an insulating material, and the printed wiring of the two printed boards 31 and 35 may be connected by a lead wire or the like.

According to the present invention, as described above, the relatively small first
Light receiving element 33 and preamplifier 41 on a printed circuit board 31
And a second circuit section 43 including a main amplifier section 44 and fire discriminating sections 45 to 49 on a second printed circuit board 35 larger than the first printed circuit board 31. , These first and second printed circuit boards 3
Since both the printed circuit boards 1 and 35 are arranged in two upper and lower stages, the printed circuit board 3 can be narrowed even when the upper part is narrowed and the volume is smaller than the lower part.
1 and 35 can be easily accommodated, and the light receiving element 33 is fixed on the first printed circuit board 31 and connected to the first printed circuit board 31, or the first light receiving element 33 is connected to the first printed circuit board 31 by a short lead wire.
Connected to the light-transmitting window 14.

FIG. 6 is a partial sectional view of another embodiment of the present invention. In this embodiment, the light-transmitting window 14 of the cover 13 is provided with a light-shielding wall 14a composed of a flange portion 14b and a cylindrical portion 14c provided at the center of the light-receiving element 33 and surrounding the light receiving element 33. Thus, it is possible to prevent the sunlight transmitted through the light transmitting window 14 from irradiating the side wall of the light receiving element to heat the light receiving element, output a detection signal, and causing a malfunction.

[0023]

As is apparent from the above description, according to the present invention, the first printed circuit board is provided with the first circuit section including the light receiving element and the preamplifier section, and the second printed circuit board is provided with the main amplifier section and the fire circuit. Since the second circuit section including the discriminating section and the like are provided and arranged in two upper and lower stages, the following remarkable effects can be obtained.

(1) Even in the case of a substantially Mt. Fuji-shaped casing whose upper part is narrowed down, the electric circuit section can be accommodated in the casing by bringing the light receiving element close to the light transmitting window.

(2) Since the length of the lead wire from the light receiving element to the first printed circuit board can be shortened, it is possible to largely prevent the lead wire from acting as an antenna to pick up electromagnetic waves.

(3) Since the length of the lead wire can be shortened, it is difficult to bend even when subjected to an impact or the like, so that the position and sensitivity of the light receiving element can be prevented from being out of order. Also, the mounting can be omitted.

(4) Since the light receiving element can be directly fixed to the first printed circuit board, the light receiving element does not largely move even if the sensor receives vibration or the like as in the related art. For this reason, even when a pyroelectric element is used as the light receiving element, occurrence of malfunction due to vibration or the like can be greatly reduced.

(5) Since the electric circuit section is composed of two printed boards, electric components mounted on the printed circuit board can be dispersed. For this reason, the first and second printed circuit boards can be downsized, and the housing for housing them can also be downsized.

(6) Since the preamplifier is provided on the first printed circuit board on which the light receiving element is mounted and the distance between the light receiving element and the preamplifier can be minimized, the influence of noise can be greatly suppressed. it can.

(7) When a fin is provided from the side wall of the cylindrical portion of the case to the inclined portion, when the sensor is attached to or detached from the base, the attachment / detachment jig is engaged with the fin to rotate the sensor. This makes it very easy to attach and detach the sensor to and from the base. (8) Small first device provided with light receiving element, preamplifier, etc.
And a large second printed circuit board provided with a main amplifier section, a fire discriminating section, etc., are arranged in two stages via spacers. Can also be easily accommodated.

[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. 1;

FIG. 3 is a circuit diagram of an embodiment of an electric circuit section of the present invention.

FIG. 4 is a plan view of an embodiment of a printed circuit board incorporating the electric circuit unit of FIG. 3;

FIG. 5 is a side view of FIG. 4;

FIG. 6 is a partial sectional view of another embodiment of the present invention.

FIG. 7 is a longitudinal sectional view of an example of a conventional radiation fire detector.

DESCRIPTION OF SYMBOLS 10 Housing 11 Main body 12 Bottom plate 13 Cover 14 Light-transmitting window 30 Electric circuit unit 31 First printed circuit board 32 Shield case 33 Light receiving element 35 Second printed circuit board 37 Spacer 40 First circuit unit 41 Preamplifier Part 43 Second circuit part

Claims (2)

(57) [Claims] 1. A fire flame on an upper bottom having a bottomed cylindrical main body and an inclined portion connected to the main body and reduced in diameter upward .
A housing comprising a cover provided with a light-transmitting window for transmitting light emitted from the housing; a small first printed circuit board housed in an inclined portion of the housing; The first print coupled downward and housed in the housing
A second printed circuit board large than the substrate, the housing of the transparent window and is arranged One put mounting to the first printed circuit board connected to the magnetic between the first printed circuit board
Light receiving element that detects light from a fire flame transmitted through an optical window
And a first circuit unit having a preamplifier unit for amplifying at least an output signal of the light receiving element on the first printed circuit board.
Providing the first printed circuit board on the second printed circuit board.
A radiant fire detector provided with a second circuit unit excluding the circuit unit of (1). Wherein said cover includes a cylindrical portion translucent window is provided on the upper base with a diameter smaller than the bottom to the top of the inclined portion of the housing,
2. A radiant fire detector according to claim 1, wherein a plurality of fins are provided at substantially equal intervals from the side wall of the cylindrical portion to the inclined portion.