JP3357330B2 - Flame 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 detector for detecting a flame by detecting a radiant energy obtained by observing a flame, and more particularly to a flame detector for detecting a detection signal detected by a light receiving element. The present invention relates to a flame detector provided with a signal amplifier for amplifying a flame.

[0002]

2. Description of the Related Art Conventionally, a radiation type flame detector used for detecting a fire source such as a flame is roughly divided into radiant energy from a flame or the like (particularly, infrared energy) as shown in FIG. ), And from the detection signal Sp detected and output by the light receiving element, only the signal component Ap of a specific frequency band used in the flame determination processing is passed. Pre-filter 2
0, a preamplifier 30 that amplifies the signal component Ap that has passed through the prefilter 20 to a predetermined signal level in a first stage, a main amplifier 40 that amplifies an output from the preamplifier 30 to a signal level suitable for signal processing described later, Main amplifier 4
An analog-to-digital converter (hereinafter, referred to as an analog-to-digital converter) that converts an amplified output (analog signal) Bp output from 0 to a digital signal
An A / D converter 50) and a flame determination processing unit 60 that executes detection determination processing for a flame or the like based on the amplified output obtained by the A / D conversion.

In such a flame detector, when a flame is observed by the detection sensor 10, a detection signal Sp corresponding to the radiant energy of the flame is output, and only a signal component Ap in a frequency band used for flame determination is extracted. , And is input to the flame determination unit 60. That is, the flame determination processing has been executed based on the signal components included in the specific frequency band.

[0004]

However, the prior art as described above has the following problems. (1) In the above-described flame detector, as shown in FIG. 8, of the detection signal Sp output from the detection sensor 10, the signal component Ap included in a specific frequency band is converted by the preamplifier 30 and the main amplifier 40. At the time of amplification, the noise component Np included in the frequency band is also amplified at a predetermined amplification rate together with the original flame detection component Dp. Therefore, the absolute level of the noise component Np ′ included in the amplified output Bp output to the flame determination processing unit 60 increases, thereby affecting the flame determination processing in the flame determination processing unit 60, so that accurate flame determination can be performed. There was a possibility that it would not be done.

(2) In the detection sensor 10,
Due to the deterioration of the characteristics of the light receiving element provided in the detection sensor 10 or the contamination of the protective translucent window disposed in front of the light receiving element,
When automatically adjusting the detection sensitivity in response to changes in the detection area or sensitivity over time, or when adjusting the detection area or sensitivity at the installation site of the flame detector, the amplification factor of the amplifier The width of the change control is narrow, and the amplification margin is low. For this reason, the detection performance of the flame detector tends to vary, and there is a possibility that accurate flame determination may not be performed.

In view of the above problems, the present invention suppresses a noise component included in a detection signal output from a detection sensor with a simple configuration, and satisfactorily extracts and amplifies an original flame detection component. It is another object of the present invention to provide a flame detector capable of performing more accurate flame determination.

[0007]

According to a first aspect of the present invention, there is provided a flame detector, comprising: a detection sensor for converting light energy into an electric signal; and amplifying means for amplifying and outputting an output signal from the detection sensor. A flame detector comprising: a flame determination unit that determines a flame based on an amplified output that is output from the amplification unit.The flame detection unit is configured to monitor substantially the same detection area substantially simultaneously, and , Almost the same sensitivity
A plurality of individual output light-receiving elements with characteristics
The detection sensor outputs from each of the plurality of light receiving elements.
Pass only the specified frequency band components of the input detection signal.
A plurality of pre-filters having substantially the same characteristics
, And the amplification means adds and amplifies individual outputs from the light receiving elements. A flame detector according to a second aspect of the present invention is the flame detector according to the first aspect, wherein the amplifying means includes a preamplifier for amplifying each individual output from the light receiving element in a first stage; Main amplifying means for amplifying the output from the amplifying means to a predetermined signal level, wherein the output lines from the respective preamplifying means are connected to each other and output to the main amplifying means, so that addition amplification is performed. It is characterized by.

The flame detector according to a third aspect of the present invention is the flame detector according to the second aspect, wherein the flame detector includes switching means for switching and connecting output lines from the respective preamplifiers. It is characterized by having. A flame detector according to a fourth aspect of the present invention is the flame detector according to the first aspect,
The detection sensor is characterized in that a plurality of the light receiving elements are arranged and packaged integrally. The flame detector according to the fifth aspect of the present invention is the first aspect of the invention.
In the above flame detector, the detection sensor is characterized in that a plurality of light receiving elements of the same type are individually packaged and arranged in close proximity. A flame detector according to a sixth aspect of the present invention is the flame detector according to any one of the fourth and fifth aspects, wherein the plurality of light receiving elements are formed with the same element size. I have. A flame detector according to a seventh aspect of the present invention is the flame detector according to any one of the fourth and fifth aspects, wherein the plurality of light receiving elements include those formed with different element dimensions. Features.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 is a schematic configuration diagram showing a first embodiment of a flame detector according to the present invention, and FIG. 2 is a sensor section applied to the flame detector according to the present embodiment. FIG. 3 is a diagram showing an example of the arrangement of light receiving elements in a sensor unit applied to the flame detector according to the present embodiment.

As shown in FIG. 1, the flame detector according to this embodiment is roughly divided into infrared energy (light energy).
Are converted into electric signals and output.
From the sensor unit (detection sensor) SEN including 10d and the detection signals Sa to Sd output from the sensor unit SEN,
A filter unit FLT that passes only signal components Aa to Ad of a predetermined frequency band, and an addition amplifying unit (amplifying unit) AMP that adds (integrates) the signal components Aa to Ad and amplifies the signal.
And a signal processing section (flame determination means) PRO for determining a flame based on the amplified output output from the addition amplification section AMP.

Hereinafter, each component will be described in detail. (A) Sensor unit SEN / Filter unit FLT The sensor unit SEN is set to have substantially the same detection area, and detects a plurality of light receiving elements 10a to 10d that detect infrared energy from a heat source such as the flame FR substantially simultaneously.
And the filter unit FLT includes the light receiving element 1
Detection signals Sa to Sd output from each of 0a to 10d
From the pre-filters 20a to 20b that pass only the signal components Aa to Ad of the specific frequency band used in the flame determination process.
20d. Here, the sensor unit SE
N will be described in detail with reference to FIG.
As shown in FIG. 5, a substrate 101 on which a plurality of light receiving elements 10a to 10d are formed, a substrate mounting portion 102 for supporting the substrate on a base 103, and a terminal 104 extending from the rear side of the substrate mounting portion. And a cover member 106 provided with a protective light-transmitting window 105 as an optical wavelength filter in front of the light receiving elements 10a to 10d. I have.

As an example of the arrangement of the light receiving elements 10a to 10d applied to such a sensor section SEN, for example, FIG.
As shown in (a) to (c), on a single substrate 101,
A plurality of (four in the present embodiment) light receiving elements 10a to 10d having the same element size (size), that is, the same detection sensitivity, a matrix (FIG. 3A) or a linear (FIG. (B)) Or staggered (Fig. 3 (c))
And the like can be applied. Here, the array means a light receiving element group formed on the same substrate by the same manufacturing process so as to have the same sensitivity characteristics.

Each of the light receiving elements 10a to 10d
Are set so as to monitor substantially the same detection area at substantially the same time, and are configured to individually output the detection signals Sa to Sd to the pre-filters 20a to 20d. 1 and 3, the configuration of the sensor unit SEN including four light receiving elements 10a to 10d is shown for convenience of explanation. However, the number of light receiving elements, the arrangement method, the element size, and the like are described. , Is not limited at all. In general, the detection output level is substantially proportional to the area of the light receiving element. Therefore, the larger the element size of each light receiving element and the total element size, the higher the detection output level can be obtained.

As described above, the light receiving elements 10a to 10d
Are formed in an array and packaged, the configuration of the sensor unit SEN can be reduced in size, the detection sensitivity characteristics of each light receiving element are made substantially uniform, and the detection signals Sa to Sd are made substantially equivalent ( (Sa ≒ Sb ≒ Sc ≒ Sd), and in addition amplification of signal components described later, only the original flame detection component can be satisfactorily revealed. The specific operation of the addition and amplification of the signal components will be described later. Further, as another configuration example of the sensor unit SEN, in FIG. 2, a plurality of sensor modules of the same type prepared and packaged by forming a single light receiving element having a predetermined element size on the substrate 101 are prepared. A configuration in which these are arranged close to each other can be applied.

By arranging a plurality of individually and independently packaged sensor modules of the same type in close proximity to each other, the above-described array-like light receiving elements 10a to 10a
Compared to 10d, although the configuration of the sensor unit SEN becomes larger or the installation space is limited, a relatively inexpensive general-purpose light receiving element can be applied. The sensor unit SEN can be configured inexpensively and easily. In addition, even with such a configuration, similarly to the above-described configuration, the detection sensitivity characteristics are made substantially uniform, and the detection signals Sa to Sd are made substantially equal (Sa {Sb}).
Sc ≒ Sd).

(A) Addition amplification section AMP The addition amplification section AMP is composed of a plurality of preamplifiers which respectively amplify the signal components Aa-Ad individually input via the pre-filters 20a-20d at a predetermined amplification rate. (Preamplifier) 30a to 30d and preamplifiers 30a to 30d
A main amplifier (main amplifying means) 40A for amplifying an output signal obtained by connecting and connecting the output lines L1a to L1d (adding the output signals) to a signal level suitable for signal processing described later.
, And is configured.

Here, the amplified outputs of the preamplifiers 30a to 30d are output via output lines L1a to L1d, added and synthesized at a contact point NA, and input to the main amplifier 40A at the subsequent stage. That is, the output lines L1a to L1L
Since the amplified output output via 1d is a signal based on the detection signal obtained under substantially the same conditions (substantially simultaneously monitoring the substantially same detection area), these output lines L1
By coupling and connecting a to L1d at the contact point NA, each amplified output is integrated and S / N is improved. The main amplifier 40A amplifies the signal component added and synthesized at the contact point NA at a predetermined amplification factor. Here, the amplification factor of the main amplifier 40A is determined by the number of installed light receiving elements (that is,
The number is set based on the number of preamplifiers installed), the amplification factor of the preamplifier, and the signal level required for signal processing in the subsequent signal processing unit PRO. Details will be described later.

(C) Signal Processing Unit PRO The signal processing unit PRO is based on an A / D converter 50 for converting an analog signal output from the main amplifier 40A into a digital signal, and an A / D converted amplified output. , A flame determination processing unit 60 that performs detection determination processing for flames and the like. The A / D converter 50 converts the analog signal output from the main amplifier 40A into a digital signal suitable for the subsequent flame determination processing unit 60. A / D
The conversion unit 50 is necessary only when the subsequent-stage flame determination processing unit 60 performs digital signal processing, and can be omitted in the case of a processing circuit that directly compares an analog signal level with a reference value.

The flame determination processing section 60 includes an A / D converter 50
A predetermined flame determination process is executed based on the added amplified output from (or the main amplifier 40A). As a specific method of flame detection determination, for example, a method of comparing the integrated level of the added amplified output with a predetermined flame determination level can be applied. Further, as another flame determination method, a method of determining whether or not a flicker frequency specific to a flame is obtained,
Various methods, such as a combination with a level comparison, can be applied. That is, in the flame detector according to the present embodiment, the flame output determination processing is executed by using the amplified outputs from the preamplifiers 30a to 30d and amplified by the main amplifier 40A. Note that the detection sensitivity of the flame detector is determined by the number of outputs (the number of installations) of the light receiving elements, the amplification factor in the addition amplification section, the flame determination level in the flame determination processing section 60, and the like.

Here, the difference between the flame detector according to the present embodiment and the amplification function of the flame detector shown in the prior art will be described in detail with reference to the drawings. FIG. 4 is a conceptual diagram for explaining the addition amplification operation in the addition amplification unit applied to the flame detector according to the present invention. Here, description will be made with reference to the related art shown in FIGS. 7 and 8 as appropriate. First, the above-described related art will be described. As shown in FIG. 7, a signal component A of a predetermined frequency band is obtained from a detection signal Sp output from the detection sensor 10 having a single light receiving sensor.
p is extracted and amplified by the preamplifier 30 and the main amplifier 40, for example, the preamplifier 30
10 times the amplification factor of the main amplifier 40 and 100
8A and 8B, the noise component Np based on the element characteristics of the light receiving element, the external environment, etc., together with the original flame detection component Dp included in the signal component Ap, as shown in FIGS.
Is also amplified 1000 times. For this reason, the noise component may increase, making it impossible to make an accurate flame determination.

On the other hand, in the flame detector according to the present embodiment, each light receiving element 1 provided in the sensor section SEN is provided.
0a to 10d have substantially uniform detection sensitivity characteristics, and monitor substantially the same detection area almost simultaneously, so that the detection signals Sa to Sd output from the respective light receiving elements 10a to 10d are:
It is obtained as a signal that is substantially equivalent (Sa ≒ Sb ≒ Sc ≒ Sd). Then, the signal components Aa to Ad of a predetermined frequency band are extracted from the detection signals Sa to Sd, and each of the preamplifiers 30a to 30d is extracted.
When the amplification process is performed by the main amplifier 40A and the main amplifier 40A, for example, the amplification factor of each of the preamplifiers 30a to 30d is set to 1
If it is set to 0 times, each of the signal components Aa to Ad is signal-amplified 10 times. At this time, the noise components Na to Nd included in the signal components Aa to Ad are also the original flame detection components Da to D.
The signal is amplified together with the signal d and output via the output lines L1a to L1d.

Since the output lines L1a to L1d of the preamplifiers 30a to 30d are connected and connected at the contact point NA, the amplified outputs from the preamplifiers 30a to 30d are added and synthesized (ie, integrated). As shown in FIG. 4, the original flame detection component Da appears in substantially the same band.
The absolute level of .about.Dd generally increases to the number of output lines to be coupled (ie, the number of light receiving elements installed: four times in FIG. 4), and the added output at the contact point NA is provided in the sensor unit SEN. This corresponds to a signal level of each of the detection signals Sa to Sd detected by the respective light receiving elements 10a to 10d amplified by a factor of 40 (= 4 × Sa × 10). Then, similarly to the above-described prior art, in order to realize the amplification factor of 1000 times with respect to the original flame detection component, it is necessary to perform the amplification process of 25 times with respect to the added output. The amplification factor of the main amplifier 40A is set to 25 times.

On the other hand, the noise components Na to Nd included in the signal components Aa to Ad amplified at a predetermined amplification rate by the preamplifiers 30a to 30d are output to the output lines L1a to L1.
With the configuration in which 1d is connected and connected at the contact point NA, addition and synthesis (integration) are performed, and the rate of increase appears relatively lower than the signal level of the original flame detection component D. The noise component included in the added output is also amplified by the main amplifier 40A together with the original flame detection component. However, the amplification factor is extremely low (25 times) as compared with the amplification factor of the conventional main amplifier 40 (100 times). Therefore, the noise component N appears as a signal level that is relatively greatly suppressed as compared with the original flame detection component D. As described above, the addition amplification unit AMP in the present embodiment
The reason that only the original flame detection component can be increased and the noise component can be relatively suppressed is that each light receiving element 10a
10 to 10d, the original flame detection components Da to Dd
While detecting the same object (flame) at the same time has a close correlation, the noise components Na to
Nd is based on the fact that the mutual correlation is relatively small.

The signal-to-noise ratio when the signal components Aa to Ad are added and amplified has the following characteristics. That is, when m signal components Ai from the i-th light receiving element are added, the result is expressed by the following equation using the average amplitude S of the flame detection component. ΣSi = m · S (1) On the other hand, the noise intensity can be evaluated by the square mean of its variance.
It is expressed as the following equation. √ (ΣNi ² ) = N · √m (2) Therefore, the final S / N is represented by the following equation:
By adding and combining (integrating and averaging) the outputs from the m light receiving elements, the S / N is improved by √m times. m · S / (N · √m) = (S / N) · √m (3)

Therefore, by adding and amplifying the detection outputs from the plurality of light receiving elements, a signal amplification factor equivalent to that of the related art is obtained.
(For example, 1000 times)
The amplification factor required for 0A can be greatly reduced, and only the original flame detection component can be satisfactorily amplified (10
00 times), the original flame detection component can be made more prominent, and the S / N of the added amplified output input to the signal processing unit PRO is greatly improved to perform more accurate flame determination processing. be able to.

<Second Embodiment> Next, a second embodiment of the flame detector according to the present invention will be described with reference to the drawings. FIG. 5 is a block diagram illustrating a schematic configuration of the flame detector according to the second embodiment. Here, the same components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 5, the flame detector according to the present embodiment includes a sensor unit SEN having a plurality of light receiving elements 10a to 10d and detection signals Sa output from the sensor unit SEN by observing the flame FR. To Sd, a filter unit FLT that passes only signal components Aa to Ad in a predetermined frequency band, an addition amplifier AMP that adds the signal components Aa to Ad to amplify the signal, and an amplification output from the addition amplifier AMP. A signal processing unit PR for judging a flame based on the output
O.

Here, the addition amplification section AMP outputs the signal component A
preamplifiers 30a to 30d for amplifying a to Ad in the first stage and outputting the amplified signals to output lines L2a to L2c;
, That is, switches (switching means) SW1 and SW2 for connecting / disconnecting the outputs of the preamplifiers 30b to 30d to / from the contact point NB, and switches SW1 and SW2 based on, for example, a command from the signal processing unit PRO. SW2
Control unit 7 for controlling the connection conduction / connection interruption state of the switch
0.

That is, in the flame detector according to the present embodiment, the output line L2a of the preamplifier 30a is connected to the contact NB.
, The output line L2b of the preamplifier 30b is connected to the contact NB via the switch SW1, and the addition output line L2c of the preamplifiers 30c and 30d is connected to the contact NB via the switch SW2. Connected. In the following, for convenience of explanation, the amplification factors of the preamplifiers 30a to 30d are set to the same, for example, 10 times for convenience, and the amplification factor of the main amplifier 40A is
It is assumed that it is set to 25 times.

Next, each connection state and its operation in the flame detector having the above-described configuration will be described with reference to the drawings. FIG. 6 is a conceptual diagram for explaining each connection state and its operation in the flame detector according to the second embodiment. (State 1: FIG. 6A) In the flame detector having the above-described configuration, as shown in FIG. 6A, when the switches SW1 and SW2 are set to the cutoff state by the switch control unit 70, Only the detection signal Sa output from the light receiving element 10a is determined by the preamplifier 30a and the main amplifier 40A.
The signal is amplified via. Therefore, since the detection signal Sa from the single light receiving element 10a is amplified based on the amplification factors of the preamplifier 30a and the main amplifier 40A, the detection signal Sa is multiplied by 250 (= 10 × 25). The signal is input to the signal processing unit PRO.

(State 2: FIG. 6B) As shown in FIG. 6B, the switch SW is controlled by the switch control unit 70.
1 is set to the conducting state and the switch SW2 is set to the blocking state, the detection signal S output from the light receiving elements 10a and 10b
The signals a and Sb are amplified through the preamplifiers 30a and 30b, added and synthesized at the contact point NB, and output to the main amplifier 40A. Here, the light receiving elements 10a, 10
b, by monitoring substantially the same detection area at substantially the same time, the detection signals Sa and Sb have substantially the same signal level (Sa ≒ Sb). Therefore, the detection signals Sa and Sb from the sensor unit SEN are output to the preamplifiers 30a and 30b
In addition, since the addition amplification process is performed based on the amplification factors of the main amplifier 40A and the main amplifier 40A, a signal equivalent to the detection signal Sa multiplied by 500 (twice the state 1) is input to the signal processing unit PRO. .

(State 3: FIG. 6 (c)) As shown in FIG. 6 (c), the switch SW 70
1 and SW2 are set to the conductive state, the light receiving element 10
a to 10d are amplified through preamplifiers 30a to 30d, and are amplified at contact points N to N.
At B, the signals are added and synthesized and output to the main amplifier 40A. Here, the light receiving elements 10a to 10d monitor each detection signal S by monitoring substantially the same detection area substantially simultaneously.
a to Sd have substantially the same signal level (Sa ≒ Sb ≒ Sc ≒ Sd). Therefore, the detection signals Sa to Sd from the sensor unit SEN are added and amplified based on the respective amplification factors of the preamplifiers 30a to 30d and the main amplifier 40A. Is input to the signal processing unit PRO.

(State 4: FIG. 6 (d)) As shown in FIG. 6 (d), the switch control unit 70 controls the switch SW.
1 is set to the cutoff state and the switch SW2 is set to the conductive state, the detection signals Sa, Sc, and Sd output from the light receiving elements 10a, 10c, and 10d are output to the preamplifiers 30a and 30d.
The signals are amplified via c and 30d, added and synthesized at the contact point NB, and output to the main amplifier 40A. Here, the light receiving elements 10a, 10c, and 10d monitor each detection signal S by monitoring substantially the same detection area substantially simultaneously.
a, Sc, and Sd have substantially the same signal level (Sa ≒ Sc ≒ Sd). Therefore, the detection signals Sa, Sc, and Sd from the sensor unit SEN are output from the preamplifiers 30a and 30d.
c, 30d and the main amplifier 40A are subjected to the addition and amplification processing based on the respective amplification factors.
Is input to the signal processing unit PRO, which is equivalent to 750 times (3 times the state 1).

Therefore, according to the flame detector according to this embodiment, the switch control unit 70 controls the switches SW1 and SW1.
By individually controlling the ON / OFF state of SW2,
Since the number of detection signals input from the light receiving element can be increased or decreased, the detection output of the sensor unit can be arbitrarily switched and adjusted within the range of the combination of the switches.
Further, since the amplification degree of the main amplifier can be set to be significantly smaller than that of the conventional configuration, it is possible to appropriately cope with a case where a larger amplification rate is required, thereby improving the amplification margin. be able to.

In each of the above-described embodiments, the element size (size) of the light receiving element and the preamplifiers 30a to 30a
The case where the individual amplification factors of 0d are set to the same specified value has been described. However, the present invention is not limited to this, and the element dimensions (size) of the individual light receiving elements are arbitrarily changed. By setting, detection signals output from the light receiving elements having different detection output levels can be configured to be added and amplified. In this case, it is possible to form a light receiving element group in which the output characteristics are changed step by step, and the switching method of the output line using the switch control unit gives more variety to the setting method of the amplification factor. be able to.

The flame detector according to each of the above-described embodiments can be installed in any space as long as the flame can be detected and determined by detecting radiation emitted from the flame. For example, it can be favorably applied as a fire detector for a tunnel. Furthermore, in the flame detector according to each of the above-described embodiments, the amplification factor of the detection signal amplified in the addition amplification unit is set to 1000 times for convenience of explanation, but in an actual flame detector, Although, for example, an extremely high amplification factor of several thousand times to several tens of thousands or more is required, a sensor unit having a plurality of light receiving elements as shown in the above-described embodiment, and an addition amplification unit By applying the configuration having the above, the amplification factor of the main amplifier can be significantly reduced.

[0036]

According to the first aspect of the present invention, in a flame detector for judging a fire by amplifying an output signal from a detection sensor for converting light energy into an electric signal, the detection sensors are substantially the same. A plurality of light receiving elements that are set to monitor the detection area and that can output individually with substantially the same sensitivity characteristics , and furthermore, each of the plurality of light receiving elements
Detection signal output from each of the plurality of light receiving elements
Signals that pass only a predetermined frequency band component of the signal
It is equipped with a pre-filter having the characteristic, and is configured to add and amplify the output from each light receiving element, so that only the original flame detection component included in the output from the individual light receiving element is increased, By suppressing the relative values of the components, the SN ratio can be greatly improved, and more accurate flame determination can be performed. In addition, with a simple configuration in which outputs from the respective light receiving elements are added and synthesized, amplification to a predetermined signal level can be realized with a lower amplification factor than in the related art. Therefore, the amplification factor of the amplifying unit can be set smaller than that of the conventional one, so that the amplification margin can be increased.

According to the second aspect of the present invention, the amplifying means comprises: a preamplifier for amplifying each individual output from the light receiving element in the first stage; and an output from the preamplifier to a predetermined signal level. And a main amplifying means for amplifying. The output lines from the respective preamplifiers are connected to each other and output to the main amplifying means so as to amplify and add. By connecting the output line from the amplifying means and outputting to the main amplifying means, it is possible to realize amplification to a predetermined signal level at a lower amplification factor than the conventional one by a simple configuration of adding and combining. it can. Further, since the amplification degree of the main amplification means can be set smaller than that of the conventional configuration, it is possible to cope with a case where a larger amplification rate is required, and it is possible to improve the amplification margin. .
According to the third aspect of the present invention, since the flame detector is provided with the switching means for switching and connecting the output lines from the respective preamplifiers, it is possible to individually control the conduction / cutoff state of the switching means. The number of detection signals input from the light receiving element can be increased or decreased, and the detection output of the detection sensor can be arbitrarily switched and adjusted.

According to the fourth aspect of the present invention, since the detection sensor has a configuration in which a plurality of light receiving elements are arranged and is integrally packaged, the configuration of the detection sensor is significantly reduced in size. And a light receiving element group having substantially uniform sensitivity characteristics can be formed. According to the fifth aspect of the present invention, the detection sensor has a configuration in which a plurality of light receiving elements of the same type are individually packaged and arranged close to each other. Can be applied, so that the sensor unit can be configured simply and inexpensively.

According to the sixth aspect of the present invention, since the plurality of light receiving elements are configured to have the same size, a light receiving element group having substantially uniform sensitivity characteristics can be formed. The component can be made obvious, and the accuracy of the signal used in the flame determination processing in the signal processing unit can be increased. According to the seventh aspect of the present invention, since the plurality of light receiving elements include those having different sizes, it is possible to form a light receiving element group in which the sensitivity characteristic is changed stepwise and set. By controlling the switching of the output line using the switch control unit, the setting method of the amplification factor can have more variety.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a flame detector according to the present invention.

FIG. 2 is a diagram illustrating a configuration example of a sensor unit applied to the flame detector according to the first embodiment.

FIG. 3 is a diagram illustrating an example of the arrangement of light receiving elements in a sensor unit applied to the flame detector according to the first embodiment.

FIG. 4 is a conceptual diagram for explaining an addition amplification operation in an addition amplification unit applied to the flame detector according to the first embodiment.

FIG. 5 is a block diagram showing a second embodiment of the flame detector according to the present invention.

FIG. 6 is a conceptual diagram for explaining each connection state and its operation in a flame detector according to a second embodiment.

FIG. 7 is a block diagram illustrating a schematic configuration of a flame detector according to the related art.

FIG. 8 is a conceptual diagram for explaining an operation of amplifying a detection signal in a flame detector shown in the related art.

[Explanation of symbols]

 SEN sensor unit (detection sensor) AMP addition amplification unit (amplification unit) PRO signal processing unit (fire determination unit) 10a to 10d light receiving element 20a to 20d pre-filter 30a to 30d preamplifier (pre-amplification unit) L1a to L1d output line 40A main amplifier (main amplifying means) 50 A / D converter 60 flame judgment processing unit 70 switch control unit

Continued on the front page (72) Inventor Masato Aizawa 2-10-4 Kami-Osaki, Shinagawa-ku, Tokyo Hochiki Co., Ltd. (72) Inventor Manabu Mizobuchi 2-10-43, Kami-Osaki, Shinagawa-ku Tokyo Inside the company (72) Inventor Isao Asano 2-10-43 Kami-Osaki, Shinagawa-ku, Tokyo Hochiki Co., Ltd. (72) Inventor Yoshimi Kawabata 2--10-43, Kami-Osaki, Shinagawa-ku, Tokyo Hochiki Corporation (56) References JP-A-10-326391 (JP, A) JP-A-6-223284 (JP, A) JP-A-4-18698 (JP, A) JP-A-5-225460 (JP, A) JP-A-3-134798 (JP, A) JP-A-11-281475 (JP, A) JP-A-57-124756 (JP, U) JP-A-60-92385 (JP, U) (58) Int.Cl. ⁷ , DB name) G08B 17/00-17/12 G01J 1/02

Claims (7)

(57) [Claims] 1. A detector for converting light energy into an electric signal.
Sensor and the output signal from the detection sensor is amplified and output.
Amplifying means for applying power, and an amplification output outputted from the amplifying means.
Flame detection means for determining a flame by force
Wherein the detection sensor monitors substantially the same detection area at substantially the same time
Is set toHas almost the same sensitivity characteristics
A plurality of light-receiving elements capable of individual output;
The sensor detects a detection output from each of the plurality of light receiving elements.
Approximately the same that passes only a predetermined frequency band component of the signal
A pre-filter having characteristics is provided for the plurality of light receiving elements.
Prepared for each,  The amplifying unit is configured to receive the signal from the light receiving element.IndividualAdd the output of
A flame detector characterized by amplification. 2. The preamplifier for amplifying each individual output from the light receiving element in a first stage, a main amplifying unit for amplifying an output from the preamplifier to a predetermined signal level, 2. The flame detector according to claim 1, further comprising: connecting an output line from each of the preamplifiers and outputting the output to the main amplifier, thereby performing amplifying. 3. The flame detector according to claim 2, wherein the flame detector includes switching means for switching and connecting an output line from each preamplifier. 4. The flame detector according to claim 1, wherein the detection sensor includes a plurality of the light receiving elements arranged and packaged integrally. 5. The flame detector according to claim 1, wherein the detection sensor is formed by individually packaging light receiving elements of the same type and arranging a plurality of light receiving elements in close proximity. 6. The light receiving element according to claim 4, wherein each of the plurality of light receiving elements has the same element size.
The flame detector according to any one of the above. 7. The flame detector according to claim 4, wherein the plurality of light receiving elements include elements formed in different element dimensions.