JPH0652192B2 - Flame detector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a flame detection device for detecting a fire such as a fire by utilizing a fluctuation phenomenon of a flame.

(Prior Art) Since a flame generated by a fire has a fluctuation, it is known that the flame is detected by focusing on this and using the level fluctuation frequency of the signal from the infrared detector as a detection parameter. However, outside light, especially sunlight, also contains infrared components, and changes in the intensity of light rays reflected from reflective objects such as window glass that vibrate slightly due to vibration and wind also change in the same manner as flame fluctuations. Therefore, there is a problem that a detection error occurs due to this influence.

In order to solve such a problem, as shown in FIG. 4, the infrared detector A and a plurality of visible light sensors B, B arranged around the infrared detector A are used, and the output from each sensor A, B is used. It is proposed that the signal is amplified by the high gain amplifiers C and D, the fluctuation of the external light is removed by the phase comparator E, and then the presence or absence of a component of a specific frequency, usually 3 to 30 Hz, is detected by the signal processing circuit F. . (JP-A-62-19724).

Because of the fact that such a flame detector is usually attached to a ceiling or wall surface for use, it is required to be as compact as possible before being commercialized and to be shaped into a shape that takes the design into consideration. .

FIG. 5 shows an example of a conventional flame detector, which is a bowl-shaped case L provided with a light introduction window K having a light projecting plate J for transmitting infrared light and visible light fixed to a central portion thereof. , An infrared detector A, a visible detector B, a sensor chamber constituent member M accommodating a visible detector B, a power supply circuit board N, a shield plate P, and a signal processing circuit board Q.

That is, the sensor chamber constituent member M is fixed to the case L by a screw R so as to face the light introduction window K, and the visible light detectors B and B are fixed to the case L via a detector mounting plate S. The power supply circuit board N is fixed to the upright pillar T, the shield plate P is fixed to the upper part of the power supply circuit board N via the pillar U, and the signal processing circuit board Q is fixed to the pillar V above the shield plate P for detection. The device B and the signal processing circuit board Q, and the power supply circuit board N and the signal processing circuit board Q are connected by the conductive wire X.

By the way, in an instrument provided with such a light introducing window K, dust in the air adheres and the light transmittance is lowered due to long-term use. Therefore, it is necessary to clean the light introducing window at regular intervals. And Therefore, it is necessary to disassemble the circuit board or the like from the case to expose the window member, but the sensor chamber constituent member M located above the light introduction window K is fixed to the case body L with screws R. Since the shield plate P, the signal processing circuit board Q, etc. are fixed by screws on the basis of this, it is necessary to remove the parts here in order, and it takes a lot of trouble to disassemble and reassemble. was there.

The present invention has been made in view of such a problem, and an object thereof is to provide a flame detection device in which disassembling and assembling work is simplified.

(Means for Solving the Problem) In order to solve such a problem, according to the present invention, a bowl-shaped case main body having a light introduction window at the center of the bottom and a sensor chamber constituent member can be inserted at the center. A power supply circuit board formed by mounting a power supply circuit component on a board having a through hole, and a sensor chamber constituent member having a sensor housing body are fixed in the center, and infrared detection means is fitted to the housing body. And a signal processing circuit board to which a visible light detector is fixed, a shield member located between the power supply circuit board and the signal processing circuit board and fixed to the signal processing circuit board, and an opening of the case body is sealed. And a lid plate to
The power supply circuit board and the signal processing circuit board were fixed to the case body.

(Function) Since the infrared detector, visible light detector, shield plate and sensor chamber component are integrally attached to the signal processing circuit board, the infrared detector, visible light can be extracted by pulling out the signal processing circuit board from the case. The detector, the shield plate, and the sensor chamber constituent member can be pulled out at the same time, and the light guide plate can be exposed through the through hole of the power circuit board. Further, upon assembling, the signal processing circuit board is set to the original position and only this is screwed to complete the assembly in a movable state, and the disassembling and assembling work can be simplified.

(Example) Therefore, the details of the present invention will be described below based on an illustrated example.

FIGS. 1 and 2 show an embodiment of the present invention, in which reference numeral 1 is a bowl-shaped case body made of synthetic resin, and a through hole 2 is formed in the central bottom portion thereof. The translucent plate 3 capable of transmitting infrared light and visible light is fixed by the pressing member 4 to form the light introduction window 5, and the side wall portion 6 is provided with a power supply circuit board 11 and a signal processing circuit board 35 described later. Supports 7, which are held at a constant interval, that is, at a distance at which the connectors 15 and 47 can be fitted,
7, 7, 8, 8, 8 are provided, and the conductive layer 1 is formed on the entire inner surface.
0 is formed.

Reference numeral 11 denotes the above-described power supply circuit board, which is a sensor chamber constituent member 2
Substrate 13 having through hole 12 for inserting 1 in the central portion
A switching regulator circuit component (not shown) is mounted on the top of the case body 1, and connectors 15 and 16 for connecting to an external circuit or a signal processing circuit board are fixed to the surface of the case body 1 that is an upper side in the figure when it is arranged. It is fixed to the case body 1 with screws 17 while being supported by 7, 7, 7.

Reference numeral 19 denotes an aluminum shield plate for static electricity and electromagnetic shielding arranged between the power supply circuit board 11 and the signal processing circuit board 35. The shield plate 19 is provided with the light introduction window 5 on the lower surface when installed in the case body 1. The sensor chamber constituting member 21 is fixed with screws 22 at a position facing each other, that is, at the center, and notches 25, 25 are formed at positions facing the connectors 15, 16.

The sensor chamber constituent member 21 is made of a metal or a synthetic resin material having a conductive layer 23 on the surface, and has an infrared detector accommodating body portion 27 in the central portion and an integrating chamber 29 formed so as to surround the same. Visible light detector accommodating body portions 31, 31 arranged at equal intervals are formed on the upper portion, and a diffusion plate 33 is formed at the tip.
It is configured by fixing.

Reference numeral 35 denotes the above-mentioned signal processing circuit board. The sensor chamber constituent member 21 is fixed integrally with the shield plate 19 by the screw 20 in the central portion of the lower surface when set in the case body 1, and infrared detection is performed. For example, a pyroelectric infrared detector 37 that selectively detects light having a wavelength of 4.3 μm is provided at a position facing the container housing body 27, and the visible light detector housing body 3 is also provided.
A visible light detector 39 is attached at a position opposed to 1. A first-stage amplifier circuit (not shown) that amplifies signals from the detectors 37 and 39 is intensively mounted on the upper surface side when set in the case body 1 in the central portion of the circuit board 35. The upper part of the shield case 4 made of aluminum plate
1, a phase detection circuit component (not shown) is mounted on the outer periphery thereof, and a connector 47 is fixed at a position facing the connector 15 of the power supply circuit board 11. The circuit board 35 has its connector 47 fitted to the connector 15 of the power supply circuit board 11, is supported by the column 8 of the case side wall 6, and is fixed to the case body 1 by the screw 49.

Reference numeral 51 is a cover plate made of synthetic resin. A conductive layer 53 is formed on the inner surface side, and a shield wire 58 of a shield cable 55 connected to an external device is formed on the conductive layer 53.
Are connected.

At the stage where all the components are housed and fixed in the case body 1,
Connect the connector 57 of the shielded cable 55 to the power circuit board 1
The lid plate 51 is joined to the connector 16 of No. 1 and the lid plate 51 is set in the opening of the case main body 1 and the both are fixed by screws 59 or the like. As a result, the case body 1 and the cover plate 51 are connected to the conductive layers 10, 53.
And the whole case is grounded via the shield wire 58 of the shielded cable 55. The infrared detector 37 and the visible light detector 39 are the sensor chamber constituent members 2
The circuit on the signal processing circuit board 35 is shielded by the conductive layer 23 of 1 and the shield case 41 on the upper surface.
It is electrostatically shielded by the shield plate 19 and the shield case 41 and protected from environmental noise.

In this embodiment, in the absence of flame, the infrared component contained in the external light, especially the sunlight, is detected by the infrared detector 37, and the visible light component is detected by the visible light detectors 39, 3
The signals are converted into electric signals by 9, 39 and input to the processing circuit on the signal processing circuit board 35. At this time, even if the incident external light has a fluctuation component of the same frequency as the flame,
Since the infrared component and the visible light component both have the same fluctuations, they have the same phase and therefore cancel each other out, which does not result in erroneous detection.

On the other hand, when a flame is generated, the flame contains an infrared component that is much stronger than the visible light component as compared with the external light, and therefore the fluctuation of the signal from the infrared detector 37 is caused by the visible light detector 39. The signal from will not be offset and will be detected reliably.

When the light-transmitting plate 3 forming the light introduction window 5 becomes cloudy due to long-term use, the case body 1 is covered with the cover plate 51.
Then, the signal processing circuit board 35 can be removed from the case body 1 by removing the screws 49 that fix the signal processing circuit board 35 to the case body 1. When the signal processing circuit board 35 is pulled out from the case body 1 in this state,
The connectors 15, 47 are automatically disconnected from each other, and the infrared detector 37, the visible light detector 39, the shield plate 19, the sensor chamber constituent member 21, and the diffusion plate 33 fixed to the signal processing circuit board 35 are integrated. The light introduction window 5 is exposed through the through hole 12 in the center of the power supply circuit board 11 (FIG. 3). This makes it possible to clean the front and back surfaces of the translucent plate 3 with a cloth or the like.

When cleaning is completed, the connector 57 of the shielded cable 55 is fitted to the connector 16 of the board 11, and the signal processing circuit board 35 is further aligned with the connector 47 attached to the signal processing circuit board 35 and the connector 15 of the power supply circuit board 11. After doing
The signal processing circuit board 35 is attached to the support column 8 of the case body side wall portion 6,
By assembling it in a operative state by mounting it on the screws 8 and 8 and fixing it with screws, the assembly is completed.

(Effects of the Invention) As described above, in the present invention, a bowl-shaped case body having a light introduction window at the center of the bottom and a substrate having a through hole for allowing the sensor chamber constituent member to be inserted are provided at the center. The power supply circuit board on which the power supply circuit components are mounted and the sensor chamber constituent member having the sensor housing body are fixed in the center, and the infrared detecting means and the visible light detector are fixed in accordance with the housing body. A signal processing circuit board, a shield member that is located between the power supply circuit board and the signal processing circuit board and is fixed to the signal processing circuit board, and a lid plate that seals the opening of the case body. Since the power supply circuit board and the signal processing circuit board are fixed to the case body, the infrared detector, visible light detector, shield plate, and sensor chamber components can be removed from the case simply by removing the signal processing circuit board. It can be integrally drawn out, and the light guide plate can be exposed through the through hole of the power circuit board. When assembling, set the signal processing circuit board to the original position and fix it with screws to complete the assembly.
The disassembling and assembling work can be simplified.

[Brief description of drawings]

1 and 2 are sectional views of an apparatus showing an embodiment of the present invention,
FIG. 3 is an exploded perspective view showing components, FIG. 3 is a sectional view showing a state in which a circuit board on the case opening side is removed, and FIGS. 4 and 5 are a block diagram and a sectional view showing an example of a conventional flame detection device, respectively. is there. 1 ... Case main body, 2 ... Through hole 3 ... Translucent plate, 5 ... Light introduction window 6 ... Side wall part, 7, 8 ... Posts 10 ... Conductive layer, 11 ... Power supply circuit board 12 ... … Through hole, 15 …… Connector 17 …… Screw, 19 …… Shield plate 21 …… Sensor chamber component 27 …… Infrared detector accommodating cylinder 29 …… Integral chamber 31 …… Visible light detector accommodating cylinder 33 …… Diffusion plate, 35 ... Signal processing circuit board 37 ... Infrared detector 39 ... Visible light detector 41 ... Shield case

Claims (1)

[Claims] 1. A power supply comprising a power supply circuit component mounted on a substrate having a bowl-shaped case body having a light introducing window at the center of the bottom and a through hole formed at the center for allowing a sensor chamber component to be inserted therethrough. A signal processing circuit board having a circuit board and a sensor chamber constituent member having a sensor housing body fixed in the center, infrared detection means and a visible light detector fixed to the housing body, and the power supply circuit. The power supply circuit board and the signal processing circuit board are provided with a case, which includes a shield member located between the board and the signal processing circuit board and fixed to the signal processing circuit board, and a lid plate for sealing the opening of the case body. Flame detector fixed to the body.