JPH06138031A - Analog output type photoelectric smoke detector - Google Patents

Abstract

PURPOSE:To provide an analog output type photoelectric smoke detector which can properly detect the state where the luminous amount of a light emitting element is reduced regardless of the contamination, etc., inside a chamber. CONSTITUTION:In this detector for receiving the light which is projected from a light emitting element 10 and is scattered by smoke M inside a chamber C and for outputting an analog signal with the output level according to the intensity of the scattered light, a part 8 between the light emitting element 10 and the light reception element 20 is made of a transmission material for allowing light with a wavelength output from the light emitting element 10 to be transmitted and one part of the light projected from the light emitting element 8 is transmitted through the transmission material and enters the light reception element 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in an analog output type photoelectric smoke detector.

[0002]

2. Description of the Related Art A basic structure of a conventional analog output type photoelectric smoke detector is, for example, as shown in FIG. 7, a light emitting element A and a light receiving element B are divided into a chamber C having a maze structure. The light receiving element B is provided so as not to directly receive the light from the light emitting element A. The light scattered by the smoke that has entered the chamber C is received by the light receiving element B.
When the light is received by, the analog signal of the output level corresponding to the smoke density is output. That is, in the smoke detector, as shown in FIG. 8, when the smoke concentration in the chamber C becomes higher, the output level of the analog signal output from the light receiving element B also becomes higher, and this output level exceeds the constant value VTH. At that point, an alarm device separately connected to the smoke detector can be used to issue an alarm or the like.

[0003]

However, as the above-mentioned conventional light emitting element A, for example, a light emitting diode or other element is used, and these light emitting elements A emit light (luminance) due to long-term use of the smoke sensor. ) Occurs considerably lower. When the amount of light emitted from the light emitting element A decreases, not only the smoke sensing ability decreases due to the decrease in the amount of smoke scattered light, but also a large amount of smoke is present in the chamber C due to a fire or the like. Regardless, the output level of the signal output from the light receiving element B is the predetermined value VTH
However, there was a fatal difficulty that the prescribed notification could not be made.

Conventionally, as a measure for solving such a difficulty, the light emitting element A is caused to emit light in the absence of smoke in the chamber C so that the light receiving element B receives the amount of light diffusely reflected on the inner wall surface of the chamber C. There is also a means for detecting the output level when the light emitting element A is made to emit light and periodically determining whether or not the light emitting element A emits light with sufficient brightness. However, in such means, the amount of light received by the light receiving element B depends on how dirty the inner wall surface of the chamber C is. That is, the reflectance of the light is different when the inner wall surface of the chamber C is stained whitish and when it is stained black. Therefore, it is difficult to accurately determine whether or not the light emission amount of the light emitting element A actually decreases by receiving the light diffusely reflected by the inner wall surface of the chamber C.

The present invention has been proposed in view of the above points, and is not affected by the degree of dirt in the chamber,
To provide an analog output type photoelectric smoke detector capable of accurately detecting a decrease in light emission amount of a light emitting element.
Its purpose is.

[0006]

SUMMARY OF THE INVENTION An analog output type photoelectric smoke detector according to the present invention as set forth in claim 1 proposed to achieve the above object, is a smoke emitted from a light emitting element to emit smoke in a chamber. In the analog output photoelectric smoke detector that receives the scattered light scattered by the light receiving element and outputs an analog signal of an output level according to the intensity of the scattered light,
The portion between the light emitting element and the light receiving element is formed of a transmissive material that transmits light of a wavelength projected from the light emitting element,
A part of the light projected from the light emitting element is configured to pass through the transparent material and enter the light receiving element.

According to a second aspect of the present invention, there is provided an analog output type photoelectric smoke detector in which light emitted from the light emitting element is inserted into a light blocking portion provided between the light emitting element and the light receiving element. Is provided with a light passing hole for allowing a part of the light to enter the light receiving element.

According to a third aspect of the present invention, there is provided an analog output photoelectric smoke detector according to the present invention, wherein:
A light-transmitting material that transmits light having a wavelength emitted from the light-emitting element is embedded in the light-transmitting hole so that part of the light from the light-emitting element enters the light-receiving element through the light-transmitting material. Is configured.

According to a fourth aspect of the present invention, in the analog output type photoelectric smoke detector, the light receiving element for directly receiving a part of the light projected from the light emitting element is a light receiving element for receiving scattered light. Is a separate structure.

According to a fifth aspect of the present invention, there is provided an analog output photoelectric smoke detector according to the present invention, wherein the output level of the analog signal output from the light receiving element is the same as that of any one of the first to fourth aspects. When is below a certain value, the fact is notified.

[0011]

In the analog output photoelectric smoke detector according to the present invention having the above-mentioned structure, a part of the light projected from the light emitting element is between the light emitting element and the light receiving element. The light is transmitted through the transparent material provided in the light receiving element and is incident on the light receiving element. Therefore, if the amount of light emitted from the light emitting element decreases, the amount of light received by the light receiving element that passes through the transparent material also decreases in a state that accurately corresponds to the decrease in the amount of light emission, and the signal level output from the light receiving element decreases. Also decreases correspondingly. As a result, the decrease in the amount of light emitted from the light emitting element can be accurately detected without being affected by dirt or the like in the chamber. The light transmitted through the transparent material and received by the light receiving element is not the total amount of light projected from the light emitting element,
As part of that, smoke sensing inside the chamber can be properly done by the light projected into the chamber,
No trouble will occur.

In the analog output type photoelectric smoke detector according to the present invention as defined in claim 2 or 3, a part of the light projected from the light emitting element is between the light emitting element and the light receiving element. The light is transmitted through the light-transmitting hole or the light-transmitting material embedded in the light-transmitting hole, and is received by the light-receiving element. Therefore, as in the case of claim 1, when the light emission amount of the light emitting element decreases, the light amount received by the light receiving element via the light transmitting hole also decreases correspondingly.
It is possible to detect the decrease in the light amount of the light emitting element regardless of the contamination in the chamber. Incidentally, in claim 3,
By embedding the translucent material in the light transmitting hole, it is possible to appropriately prevent dusts from entering the light transmitting hole.

In the analog output type photoelectric smoke detector according to the present invention as defined in claim 4, a part of the light projected from the light emitting element is provided separately from the light receiving element for receiving scattered light due to smoke. The received light is directly received. Therefore, by observing the amount of light received by the light receiving element, it is possible to appropriately determine whether or not the amount of light emitted by the light emitting element has decreased.

In the analog output type photoelectric smoke detector according to the present invention as defined in claim 5, when the output level of the analog signal output from the light receiving element becomes a predetermined value or less, that is, the light emitting element emits light. When the amount of light emitted from the light receiving element decreases, the user is properly notified of the service life or the replacement time of the light emitting element.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment (corresponding to claim 1)] FIG. 1 is a sectional view showing an embodiment of an analog output type photoelectric smoke detector K according to the present invention, and FIG. 2 is a block diagram showing its circuit configuration. . Figure 1
In the smoke detector K, the light emitting element 10 and the light receiving element 20 are held in a holder 6 having a predetermined shape and separated from each other in a housing case 5 forming a chamber C through which smoke can enter. It was provided by. Here, the holder 6 has a hole 7 for projecting light from the light emitting element 10 into the chamber C, and a hole 7 for allowing scattered light of smoke in the chamber C to be received by the light receiving element 20.
Although a is formed, the light emitting element 10 and the light receiving element 2 are formed.
The portion between 0 and 0 is configured as a light transmitting portion 8 formed of, for example, an acrylic resin or the like that transmits the wavelength of light emitted from the light emitting element 10, and one portion of the light emitted from the light emitting element 10 is formed. The section is configured to be received by the light receiving element 20 via the light projecting section 8. The portions of the holder 6 other than the light-transmitting portion 8 are made of a material having no light-transmitting property. In the figure, reference numeral 9 is a light emitting element 10 or a light receiving element 2.
2 is a circuit board to which 0 is connected.
A circuit having a configuration as shown in is provided.

The circuit shown in FIG. 2 includes a light emitting element drive circuit 1 for causing the light emitting element 10 to emit light at a constant time interval, a light receiving signal amplifier circuit 2 for amplifying a signal output from the light receiving element 20 at a predetermined ratio, A peak hold circuit 3 for detecting the peak value of the signal amplified by the received light signal amplification circuit 2 in synchronization with the light emission timing of the light emitting element, and a signal output from the peak hold circuit 3 is output as a predetermined DC voltage signal. The DC amplification circuit 4 and the like are provided. In this circuit configuration, the light receiving element 20 is connected to the DC amplification circuit 4.
An analog signal having a voltage proportional to the amount of light received at is output. The direct current amplifier circuit 4 includes the direct current amplifier circuit 4
An alarm device (not shown) that issues an alarm or the like when the voltage value of the signal output from the device exceeds a predetermined constant voltage value that is set in advance is used. The alarm device is configured to issue a predetermined alarm even when the voltage value of the signal output from the DC amplification circuit 4 becomes a predetermined constant value or less. However, the notification at that time is set to be distinguished from the case where the voltage value of the signal output from the DC amplification circuit 4 described above exceeds a certain value.

Next, an example of use and operation of the smoke detector K having the above structure will be described. First, when the light emitting element 10 is made to emit light, a part of the light is projected from the hole portion 7 into the chamber C, and the remaining part is transmitted through the light transmitting portion 8 to be received by the light receiving element 20. To be done. In this state, the light receiving element 20 always receives the light transmitted through the light transmitting portion 8 regardless of the presence or absence of smoke.
When the smoke M exists in the inside, the light receiving element 20 also receives scattered light corresponding to the amount of the smoke M present. Therefore,
The signal V output from the DC amplification circuit 4 shown in FIG.
As shown in FIG. 3, the sum of the output value Va obtained by passing through the light transmitting portion 8 and being received by the light receiving element 20 and the output value Vb obtained by receiving the scattered light of smoke by the light receiving element 20 and Become. Thus, in the output signal as shown in FIG. 3, if the light emission amount of the light emitting element 10 is the same, the output value Va is constant, so the voltage value V of the entire output signal is appropriate for the amount of smoke present. The value corresponds to. Therefore, when the amount of smoke generated exceeds a predetermined reference amount due to fire or the like, the voltage value V of the entire output signal exceeds a preset voltage value VTH,
The alarm device can be triggered appropriately.

Next, due to long-term use and the like, the light emitting device 1
When the light emission amount of 0 decreases, the voltage value Va shown in FIG.
Is reduced. In such a case, the voltage value V of the entire output signal also decreases, but when there is no smoke in the chamber C and there is no output due to reception of scattered light, the output voltage value V is shown by the broken line in the figure. It falls to the area N. On the other hand, the voltage value V
Since a is transmitted by passing through the translucent portion 8 and is received by the light receiving element 20, it is output in proportion to the amount of light emitted from the light emitting element 10 and is not affected by dirt in the chamber C. Therefore, when the light emission amount of the light emitting element 10 is less than the light emission amount required for smoke detection, the output voltage value V becomes equal to or lower than the preset reference voltage value VTL. Then, at this time, the alarm device connected to the smoke sensor K issues an alarm sound or the like to notify the user that the light emission amount of the light emitting element 10 has dropped below a certain level.

[Second Embodiment (corresponding to claim 2)] FIG. 4 is a sectional view showing another embodiment of the analog output type photoelectric smoke detector Ka according to the present invention. This smoke sensor Ka is made of a material that does not allow light to pass through the entire holder 6a.
A light blocking unit 1 is provided between the light emitting element 10 and the light receiving element 20.
3 is formed, the light blocking portion 13 has a hole 7,
A light passing hole 11 is provided so as to extend through the space 7a. According to this structure, a part of the light projected from the light emitting element 10 also passes through the light passing hole 11 and the light receiving element 2
Since the light is received at 0, as in the case of the first embodiment, if the light emission amount of the light emitting element 10 decreases, the value of the output signal from the light receiving element 20 also decreases correspondingly. Therefore, when the light emitting element 10 has a desired light emission amount or less, a predetermined alarm can be issued and the user can be informed accordingly.

[Third Embodiment (corresponding to claim 3)] FIG. 5 is a sectional view showing another embodiment of the analog output type photoelectric smoke detector Kb according to the present invention. This smoke detector Kb is the second
In the smoke sensor Ka shown in the embodiment, a light-transmitting material 12 such as an acrylic resin or an optical fiber for transmitting light having a wavelength projected from the light emitting element 10 is embedded in the light transmitting hole 11. . With this configuration, as in the second embodiment, part of the light projected from the light emitting element 10 passes through the translucent material 12 and is received by the light receiving element 20,
It is possible to appropriately detect the decrease in the light emission amount of the light emitting element 10. If the light-transmitting hole 11 is blocked with the light-transmitting material 12, dust will enter the light-transmitting hole 11 due to long-term use,
It is possible to eliminate the risk of accumulation.

[Fourth Embodiment (corresponding to claim 4)] FIG. 6 is a sectional view showing another embodiment of the analog output type photoelectric smoke detector Kc according to the present invention. This smoke sensor Kc is provided with another light receiving element 2 between the light emitting element 10 and the light receiving element 20.
0a is provided, and the light passing hole 14 is formed between the light receiving element 20a and the light emitting element 10, so that the light emitting element 10a
The light receiving element 20a can always receive a part of the light emitted from the light receiving element 20a. In such a configuration, the decrease in the amount of light emitted from the light emitting element 10 can be exclusively detected by one of the light receiving elements 20a, and when the value of the signal output from the light receiving element 20a becomes a certain value or less, a warning is issued. Will be done. Further, since the smoke M can be exclusively detected by the one light receiving element 20, the smoke can be appropriately detected.

[0022]

As can be understood from the above description, according to the analog output type photoelectric smoke detector according to the present invention described in claims 1 to 5, a part of the light projected from the light emitting element is used. Since it is possible to detect the decrease in the light emission amount of the light emitting element by directly receiving the light with the light receiving element, it is possible to detect the light emission amount of the light emitting element by receiving the diffused reflected light from the inner wall surface of the chamber. In addition, it is possible to accurately determine whether or not the light emission amount of the light emitting element is appropriate without being affected by the stain on the inner wall surface of the chamber.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an analog output type photoelectric smoke detector according to the present invention.

FIG. 2 is a block diagram showing an example of a circuit configuration of an analog output photoelectric smoke detector according to the present invention.

FIG. 3 is an explanatory diagram showing signals output from an analog output photoelectric smoke sensor according to the present invention.

FIG. 4 is a sectional view showing another embodiment of the analog output photoelectric smoke detector according to the present invention.

FIG. 5 is a sectional view showing another embodiment of the analog output photoelectric smoke detector according to the present invention.

FIG. 6 is a sectional view showing another embodiment of the analog output photoelectric smoke detector according to the present invention.

FIG. 7 is an explanatory diagram showing an example of a basic structure of a conventional analog output photoelectric smoke detector.

FIG. 8 is an explanatory diagram showing an example of a signal output from a conventional analog output type photoelectric smoke detector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 light emitting element drive circuit 2 light receiving signal amplification circuit 3 peak hold circuit 4 direct current amplification circuit 5 housing case 6 to 6c holder 7, 7a hole part 8 light transmitting part 9 circuit board 10 light emitting element 11 light transmitting hole 12 light transmitting material 13 light Blocking unit 20, 20a Light receiving element K, Ka to Kc Analog output type photoelectric smoke detector

Claims (5)

[Claims] 1. An analog output type photoelectric converter in which scattered light emitted from a light emitting element and scattered by smoke in a chamber is received by a light receiving element, and an analog signal having an output level corresponding to the intensity of the scattered light is output. In the smoke sensor, the portion between the light emitting element and the light receiving element is formed of a transmissive material that transmits light of a wavelength projected from the light emitting element,
An analog output type photoelectric smoke detector characterized in that a part of the light projected from the light emitting element is configured to pass through the transparent material and enter the light receiving element. 2. An analog output type photoelectric converter in which scattered light emitted from a light emitting element and scattered by smoke in a chamber is received by a light receiving element and an analog signal of an output level corresponding to the intensity of the scattered light is output. In the smoke detector, the light blocking section provided between both the light emitting element and the light receiving element is provided with a light passage hole for allowing a part of the light emitted from the light emitting element to enter the light receiving element. An analog output photoelectric smoke detector, which is characterized in that 3. A light-transmitting material according to claim 2, wherein a light-transmitting material for transmitting light having a wavelength projected from the light-emitting element is embedded in the light-transmitting hole, and a part of the light from the light-emitting element is contained in the light-transmitting material. An analog output photoelectric smoke detector configured to be incident on a light receiving element through the light. 4. An analog output type photoelectric converter, which receives scattered light emitted from a light emitting element and scattered by smoke in a chamber by a light receiving element and outputs an analog signal of an output level according to the intensity of the scattered light. In the smoke detector, the light receiving element for directly receiving a part of the light emitted from the light emitting element is provided separately from the light receiving element for receiving scattered light. Smoke detector. 5. The invention according to any one of claims 1 to 4, wherein when the output level of the analog signal output from the light receiving element falls below a certain value, the fact is notified. An analog output photoelectric smoke detector, which is characterized in that