JPH02227800A - Photoelectric smoke sensor - Google Patents

Abstract

PURPOSE:To decide the clogging degree of an insect net in a remote place by arranging an inspecting light emitting part or a light receiving part on the outside of the insect net, receiving inspection light through the insect net at the time of an inspection by means of the light receiving part, and observing a light emitting signal level. CONSTITUTION:An insect net 3 is loaded on the lower side of a labyrinth plate 2. A light emitting element 4 is provided inside surrounded by the labyrinth 2, and a light receiving element 5 is arranged at a position deviating by a prescribed angle with respect to the optical axis of the element 4. Further an inspecting light emitting element 7 is provided at the position directly facing the element 5. The element 7 is arranged outside the insect net 3, and at the time of the inspection, the element 5 is irradiated through the mesh of the insect net 3 by the light from the element 7. For this reason, when dirt, dust, etc., are deposited to the mesh part of the insect net 3 facing the element 7, clogs the mesh, the light from the element 7 is attenuated according to the degree of the clogging, and by observing the receiving signal level, the clogging caused by the dirt of the insect net 3 can be decided in the remote place.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a photoelectric type sensor that can automatically check the functions of the entire sensor, including the clogging of the insect screen that prevents insects from entering the smoke detection section. Regarding smoke detectors.

[Prior art] In recent years, as fire alarm equipment becomes more intelligent, automatic inspection systems have been developed. The functions of the internal electric circuit, light emitting LED, light receiving photodiode, etc. can be inspected.

[Problems to be Solved by the Invention] However, in such conventional photoelectric smoke detectors, false alarms may occur due to the intrusion of insects, etc. from the outside into the smoke detection space equipped with the light emitting LED and the light receiving photodiode. Insect screens are installed to prevent the insects from getting clogged, but in order to check whether the insect screens are clogged, it is difficult to check whether the insect screens are clogged or not by actually letting smoke flow in using a smoke testing device. This was a major obstacle in building an automatic inspection system.

The present invention has been made in view of these conventional problems, and an object of the present invention is to provide a photoelectric smoke detector that can automatically check whether an insect screen is clogged.

[Means for Solving the Problems] First, the present invention includes a light emitting unit that irradiates light onto a smoke detection space;
a light receiving section that receives scattered light from the light emitting section caused by smoke flowing into the smoke detection space; an inspection light emitting section that directly enters test light for functional inspection into the light receiving section; and the smoke detection space. This applies to photoelectric smoke detectors equipped with an insect screen to prevent insects from entering.

Regarding such photoelectric smoke detection, in the present invention, the light emitting part for inspection and/or the light receiving part is arranged outside the insect screen, and the light receiving part obtained by the light emission of the light emitting part for inspection at the time of inspection. The degree of clogging of the insect screen is determined based on the light reception signal from the insect screen.

[Function] In the photoelectric smoke detector of the present invention having such a configuration, when inspecting, for example, a light emitting part for inspection provided on the outside of the insect screen is driven to emit light, so that light is emitted through the insect screen to the light receiving part. By illuminating the test light and obtaining a light reception signal corresponding to the clogging of the insect screen, the degree of clogging of the insect screen can be determined, and all functions of the photoelectric smoke detector including the degree of clogging of the insect screen can be detected. can be automatically inspected.

[Example] Fig. 1 is an embodiment configuration diagram showing an example of the internal structure of the photoelectric smoke detector of the present invention. The top view shows the state seen from below with the holder removed.

In Fig. 1, 1 is an upper plate, and a plurality of labyrinth plates 2 are arranged at predetermined intervals in a ring shape on the upper part of the upper plate 1, and the labyrinth plates 2 allow smoke to flow from the outside to the inside. At the same time, it prevents light from entering the interior from the outside. An insect net 3 is attached to the lower side of the labyrinth plate 2 to prevent insects from entering the inside.

A light emitting element 4 using an LED is provided inside the labyrinth plate 2, and a light receiving element 5 using a photodiode or the like is arranged at a position shifted by a predetermined angle with respect to the optical axis of the light emitting element 4. 4 and the light receiving element 5, a smoke detection space 6 is formed near the intersection of their optical axes. Light-shielding plates 8 and 9 are provided on the left side of this smoke detection space 6, and the light-shielding plates 8 prevent direct light from going around from the light-emitting element 4 to the light-receiving element 5.
Further, the light shielding plate 9 can prevent light from entering the light receiving element 5 due to scattered light when water droplets or the like adhere to the tip of the light shielding plate 8, for example.

A system having a smoke detection space 6 in which the optical axis of the light receiving element 5 is shifted from the optical axis of the light emitting element 4 in this way is known as a scattered light type smoke detector. Scattered light from the light emitting element 4 is received by the light receiving element 5 to detect a fire.

Furthermore, a light emitting element 7 for inspection is installed at a position directly facing the light receiving element 5, and during inspection, the light receiving element 4 is directly irradiated with light of a predetermined intensity corresponding to fire detection. It allows you to check the functionality.

Regarding the inspection light emitting element 7 disposed opposite to the light receiving element 5, the inspection light emitting element 7 is disposed outside the insect screen 3, and the inspection light emitting element 7 that is driven to emit light at the time of inspection is essential to the present invention. The light from the element 7 is transmitted through the mesh of the insect screen 3 and irradiated onto the light receiving element 5. Therefore, if the mesh part of the insect screen 3 facing the inspection light emitting element 7 is clogged with dirt or dust, the light emitted from the inspection light emitting element 7 will change depending on the degree of clogging. Attenuated, the light receiving element 5
As a result, the level of the received light signal during inspection will decrease.

FIG. 2 is an overall sectional view of a photoelectric smoke detector having the internal structure shown in FIG. A top plate 1 having a light emitting cable 4 and a light receiving element 5 is mounted inside an outer cover 12, and a print 1 to a board 13 on which electric circuits are mounted are incorporated in the upper part of the top plate 1.

FIG. 3 is a block diagram showing the circuit configuration of a photoelectric smoke detector having the sensor structure shown in FIGS. 1 and 2. FIG.

In FIG. 3, first, an alarm indicator light/transfer circuit 15 is provided on the sensor base 14 installed on the ceiling side, and the alarm indicator light/transfer circuit 15 is connected to the sensor main body 10. The circuit is connected to the power supply/signal line from the receiver.

On the sensor main body 10 side, 16 is a rectifier circuit for making the connection polarity of the sensor non-polar, 17 is a noise absorption circuit,
18 is a polling pulse detection circuit that detects a polling pulse sent from the receiver for calling the sensor; the output of the polling pulse detection circuit 18 is given to the transmission control circuit 19; An address switch 20 is provided to set the sensor address.

When the transmission control circuit 9 determines its own address by polling from the sensor, it outputs a control signal to the power supply control circuit 21 and drives the light emitting element 4 for fire detection intermittently to emit light via the LED drive circuit 22. . Further, when inspection control is determined from the received signal following the polling pulse, a control signal is output directly to the LED drive circuit 22, and the inspection light emitting element 7
will be driven to emit light.

Further, the output of the light-receiving element ♀5, which receives the light scattered by the smoke in the smoke space of the light-emitting element 4 and also directly receives the light from the inspection light-emitting element 7, is given to the amplifier circuit 23, and the output from the amplifier circuit 23 is The obtained light reception signal is compared with a predetermined darkness value for fire judgment in the comparison circuit 24, and when the light reception signal exceeding the threshold value is obtained, the comparison circuit 24 outputs the output circuit 25.
A comparison output indicating that a fire has been detected is generated, and in response to this fire output, detection information indicating that a fire has been detected is sent to the receiver from the output circuit 25 under the control of the transmission control 19, for example, in a current mode.

In addition, the output of the amplifier circuit 23 is the sample bold circuit 2
6, the light reception signal obtained from the light receiving element 5 by the light emission of the inspection light emitting element 7 is held in the sample and hold circuit 26 during inspection, and the sample and hold circuit 26
transmission control circuit 19 by giving the output to output circuit 25
The light reception signal obtained by the light emission of the inspection light emitting element 7 under the control of
The emitted light passes through the mesh of the insect screen 3 and is received by the light receiving element 5, and a light reception signal having a signal level corresponding to the degree of dirt on the insect screen is output to the receiver side. Note that the signal level of the sample-and-hold circuit 26 is converted into a current mode signal by the output circuit 25, and is sent to the receiver side at a predetermined timing for level determination.

Further, the sample/hold circuit 26 sends out an analog level output corresponding to the smoke density via the output circuit 25 when a fire occurs.

Next, the circuit operation of the embodiment shown in FIG. 3 will be explained.

In FIG. 3, the receiver calls the sensor using a polling signal, and the polling pulse detected by the polling pulse detection circuit 18 is sent to the transmission control circuit 1.
9, the address is compared with the address based on the address switch 20, and when it is determined that the call is the same, the power supply control circuit 21 is driven to operate the LED drive circuit 22, and the light emitting element 4 for fire detection is driven to emit light. At this time, the light-receiving signal received by the light-receiving element 5 is amplified by the amplifier circuit 23, and if it is equal to or higher than the threshold value of the comparison circuit 24, the output circuit 25 outputs fire detection information to the receiver. Furthermore, in the event of a fire, an analog output corresponding to the smoke density is sent out via the output circuit 25.

On the other hand, for periodic inspection, an inspection control signal is output to the sensor once a day, for example, and upon receiving this inspection control signal, the transmission control circuit 19 causes the inspection light emitting element 7 to emit light via the LED drive circuit 22. The light receiving signal of the light receiving element 5 is amplified by the amplifier circuit 23, and sampled and held by the sample and hold circuit 26. The received light signal held in the sample/hold circuit 26 is converted into a current mode by the output circuit 25 and sent to the receiver at a predetermined timing, and the receiver side determines the degree of clogging of the insect screen 3 from the received data returned from the sensor. If the received light signal level obtained at the time of inspection has fallen below the threshold value, the insect screen is clogged and an inspection instruction is issued to encourage cleaning.

In the embodiment shown in FIG. 1, the light emitting element 7 for inspection is provided outside the insect screen 3, but the light emitting element 7 for inspection is provided inside the insect screen 3, and the light receiving element 5 is placed outside the insect screen 3. Even if it is provided outside the net 3, it is difficult.

FIG. 4 is an embodiment configuration diagram of the internal structure of a sensor showing another embodiment of the present invention, and in this embodiment, an insect screen 3
A light-emitting element 7a for inspection is provided inside the light-receiving element 5, facing the light-receiving element 5, and a light-emitting element 30 for inspection dedicated to clogging detection is provided separately from the light-emitting element 7a for inspection.

FIG. 5 is a block diagram of a sensor circuit for the sensor structure shown in FIG. 4, and a new inspection light emitting element 30 for checking clogging of the insect screen is added to the circuit block of FIG. Along with this, a delay circuit 32, a sample/hold circuit 33, and a comparison circuit 34 are added.

That is, the LED drive circuit 22 for the inspection light emitting element 7a
The drive signal is applied to the delay circuit 32 and delayed for a predetermined period of time, and then outputted to the inspection light emitting element 30 for checking whether the insect screen 3 is clogged and driven to emit light. At the same time, the output from the delay circuit 32 for the inspection light emitting element 30 is given to the sample and hold circuit 33, and the light reception signal obtained from the amplifier circuit 23 is sent to the sample and hold circuit 33 in synchronization with the light emission drive of the inspection light emitting element 30. sample and hold.

For the comparison circuit 34, there is a sample/hold circuit 26 which samples and holds the light reception signal of the light receiving element 5 caused by driving the light emitting element 7a for inspection to emit light, and a sample/hold circuit 26 which samples and holds the light reception signal of the light receiving element 5 caused by driving the light emitting element 7a for inspection to emit light. The output of the sample-and-hold circuit 33 that held the received light signal is given,
If a difference of more than a predetermined value occurs between the two hold signals, an alarm signal indicating dirt on the insect screen is sent to the receiver side via the output circuit 25.

Here, in the comparison circuit 34, a light reception signal generated by light emission from the inspection light emitting element 7a for inspecting the light receiving element 5, and a light reception signal from the inspection light emitting element 30 for inspecting the clogging condition of the insect screen 3 are received.
The reason why the degree of clogging of the insect screen is compared and judged based on the difference between the light reception signal generated by the light emitted by the light emitting elements 7a and 30 for inspection.
Similar to the insect screen 3, the amount of light emitted by the insect screen 3 decreases due to the adhesion of dirt and dust, so even if the amount of light emitted by the screen decreases due to such dirt, the difference between the two can be taken to determine the light emitting element 7a for inspection.

The influence of dirt on the 30 itself is minimized.

Of course, in the embodiment shown in FIG.
Of course, each output of the sample-and-hold circuits 26 and 33 may be sent to the receiver side and the judgment may be made on the receiver side.

[Effects of the Invention] As described above, according to the present invention, during inspection, the inspection light is received by the light receiving part through the insect screen and the level of the received light signal is checked, thereby detecting clogging of the insect screen due to dust and dirt. It can be determined remotely, and the degree of clogging due to dirt, etc. in the insect screen can be determined without actually introducing smoke using a smoke tester, etc., and the sensor can detect the degree of clogging of the insect screen, including the degree of clogging. By being able to inspect the entire system, the inspection function can be made more reliable when an automatic inspection system is constructed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of a sensor structure according to the present invention; Fig. 2 is a sectional view of the entire sensor of the present invention; Fig. 3 is a sensor used in the embodiment of Fig. 1. Block diagram of the circuit; FIG. 4 is a block diagram of another embodiment of the sensor structure according to the present invention; FIG. 5 is a block diagram of the sensor circuit used in the embodiment of FIG. 4. 1: Top plate 2: Labyrinth plate 3: Insect screen 4: Light-emitting element 5: Light-receiving element 6 Two smoke detection spaces 7a, 30: Light-emitting element for inspection 9: Light-shielding plate Detector main body Smoke inlet outside cover Printed circuit board sensor base emission Information indicator/transfer circuit Rectifier circuit Noise absorption circuit Polling pulse detection circuit Transmission control circuit Address switch Power supply control circuit LED drive circuit Light receiving circuit 34: Comparison circuit 33: Sample/hold circuit 7゜24゜26゜25: Output circuit 32 :Delay circuit

Claims (1)

[Scope of Claims] 1. A light emitting section that irradiates light to the smoke detection space, a light receiving section that receives scattered light from the light emitting section due to smoke flowing into the smoke detection space, and a light receiving section that In a photoelectric smoke detector equipped with an inspection light emitting part that directly enters test light for function inspection, and an insect screen that prevents insects from entering the smoke detection space, on the outside of the insect screen. The light emitting unit for inspection and/or the light receiving unit are arranged, and the degree of dirt on the insect screen is determined based on the light reception signal from the light receiving unit obtained by the light emission of the light emitting unit for inspection during inspection. Photoelectric smoke detector.