JPH04536B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiant infrared fire detection device.

BACKGROUND ART Conventionally, devices are already known that have a large number of light receiving elements that receive infrared rays radiated from a fire source and detect the location of a fire based on which one of the light receiving elements receives the infrared rays. This device is based on the fact that the flame from a fire emits infrared rays, but it can also be used to emit infrared rays, such as sunlight,
Various heat sources such as electric lamps and stoves also generate infrared rays, and therefore, the light-receiving element becomes sensitive to the infrared rays emitted by these heat sources, making it difficult to distinguish them from fire.

In order to eliminate such drawbacks, the applicant of this application proposed in Japanese Patent Application No. 59-008276 that the infrared rays radiated from a fire source are received by a large number of light-receiving elements.
A light receiving signal whose intensity changes due to the flickering characteristic of fire flames is input to a logic circuit, and the light receiving signals exceeding a set level are converted into pulses, and the pulses related to a predetermined number or more of adjacent light receiving elements are generated within a set time. We proposed a device that detects a fire when a predetermined number of fires are counted.

By the way, the distance between the fire source, that is, the infrared radiation source, and the light-receiving element is not constant but changes. Therefore, if the amount of light from the infrared radiation source is constant, as the distance increases, the infrared rays incident on the light-receiving element will increase. The amount of incident light becomes smaller. Therefore, in the previously proposed method, for example, if you assume an infrared source close to the light receiving element and set a setting level corresponding to the amount of incident light, the amount of infrared rays incident from an infrared light source far away from the light receiving element will be reduced. Since the amount of light from the infrared ray source is small, it does not reach the set level and a fire cannot be detected until the amount of light from the infrared source reaches a certain level.

This invention solves the problems of the previously proposed methods as described above, and improves fire detection ability by making the amount of incident light uniform regardless of the distance between the light receiving element and the infrared radiation source. The object of the present invention is to provide a radiant infrared fire detection device that can be used to detect fires.

In this invention, a large number of infrared receiving elements are disposed within a casing having an opening in which a condensing lens and an infrared filter are attached, and a number of infrared receiving elements are disposed at a distance from the condensing lens by the convergence distance thereof, and an infrared light source is A detector comprising: an adjustment member provided in the infrared incidence path for increasing the incident area of the infrared rays incident on the light receiving element through the condensing lens as the distance between the infrared ray generation source and the light receiving element increases; and a logic circuit into which a light reception signal of a level corresponding to the magnitude of the incident infrared light from each of the light receiving elements is input, and this logic circuit converts the light reception signal of a set level or higher into a pulse; It has a counter that counts the pulses output from this waveform shaping circuit, and this counter outputs a command signal when the pulses related to a predetermined number or more of mutually adjacent light receiving elements reach a predetermined number within a set time. A radiant infrared fire detection device is characterized in that it is designed to:

An embodiment shown in the drawings will be described below.

As shown in FIGS. 1 to 3, 1 is a detector,
The ring-shaped casing 2 is rotatably attached to a ceiling 4 or the like via a rotating shaft 3. The casing 2 has an opening 5, and a condenser lens 6 and an infrared filter 7 are installed in this opening 5 in order from the outside.
is installed. A light-receiving board 9 on which a large number of light-receiving elements 8 are arranged in a line is provided inside the casing 2, and each light-receiving element 8 is located at a distance from the condenser lens 6 by its focal length. Each light receiving element 8 captures the infrared rays generated within the range R, passes through the condensing lens 6 and the infrared filter 7, and inputs a light receiving signal corresponding to the magnitude of the amount of incident light to a logic circuit to be described later. It's getting old.

The incident light amount adjustment member 10 includes first and second cover plates 11a and 11b that cover the front and back surfaces of the condenser lens 6,
These first and second cover plates 11a and 11b are provided with through holes 12 and 13 which are eccentric in the front and rear directions with respect to the center of the condenser lens 6 and partially converge with each other. As is clear from FIG. 2, when the distance between the light receiving element 8, that is, the detector 1, and the position of the infrared ray generation source S is the smallest (position A), the area of the infrared ray passing portion 14 in the condenser lens 6 is The area of the infrared passing portion 14 in the condenser lens 6 is the smallest, therefore the incident area of the infrared rays is the smallest, and when the distance between the detector 1 and the position of the infrared ray source S increases (position B) increases, therefore the incident area of infrared rays increases, and when the distance between the detector 1 and the position of the infrared source S is the largest (position C), the infrared ray passing portion 14 of the condenser lens 6 increases. The area is the largest, and therefore the incident area of infrared rays is the largest, so the amount of infrared light incident on the light receiving element 8 is made uniform regardless of the distance between the detector 1 and the infrared source S. . Figure 4 shows the positions A, B, and C of the infrared source S.
The figure shows how the area of the infrared ray passing portion 14 in the condenser lens 6 changes depending on the angle.

An example of the logic circuit 15 is shown in FIG. The logic circuit 15 has a waveform shaping circuit 16 to which the light reception signals from each light receiving element 8 are input independently, and which converts the light reception signals of a set level or higher into pulses.
and a counter 17 that receives and counts the pulses. The output signals of the waveform shaping circuit 16 related to two mutually adjacent light receiving elements 8 are input to an AND gate 18, and the output signal of this AND gate 18 is input to a memory circuit 19, and also passes through an OR gate 20 to generate a pulse. The signal is input to the circuit 21. When the output signal of the OR gate 20 is input, the pulse generating circuit 21 inputs an output signal to the memory circuit 19 to start its operation, and inputs a pulse of set time length T to the counter 17. It's summery. The counter 17 receives the pulse from the waveform shaping circuit 2 while the pulse from the pulse generating circuit 21 is being input.
1 or the waveform shaping circuit 2 while the pulse is being input.
1, and when it reaches a predetermined number, it outputs a signal, and this signal passes through an OR gate 25 and is input as a command signal to, for example, an alarm circuit (not shown). We are each other.
Further, this command signal is input to the pulse generating circuit 21, so that the pulse generating circuit 21 resets the counter 17 and the memory circuit 19.

Next, the operation of the steam apparatus will be explained with reference to the time charts shown in FIGS. 6 and 7.

When the detector 1 rotates and at least two or more mutually adjacent light receiving elements 8 capture infrared rays, the rotation of the detector 1 stops and the detector 1 monitors the source of the infrared rays. That is, if the mutually adjacent light receiving elements 8 are light receiving elements 8a, 8b, 8c, 8d,... and now the light receiving elements 8b, 8c, 8d select infrared radiation, if the infrared rays are caused by flame, the light receiving elements The light reception signals from 8b, 8c, and 8d are input to the waveform shaping circuit 16 as signals having strengths and weaknesses due to the flickering characteristic of a flame, as shown in FIG. As shown in FIG. 7, the waveform shaping circuit 16 converts the light reception signals from the light receiving elements 8c and 8d, which are at a set level or higher, into pulses.
AND gate 18 associated with d outputs a signal;
The pulse generation circuit 21 is activated to activate the memory circuit 19 and the counter 17,
Further, the pulse generating circuit 21 inputs a pulse having a set time length T to the counter 17. During this time, the counter 17 counts the pulses output from the waveform shaping circuit 16 associated with the light receiving elements 8c and 8d, and when the counter 17 associated with one or both of the light receiving elements 8c and 8d counts a predetermined number, it outputs a signal. The signal is input as a command signal to an alarm circuit or the like, and the presence of a fire is recognized by appropriate means.

Further, the memory circuit 19 is configured such that the signals input thereto are based on the light receiving elements 8c and 8d;
That is, it memorizes the location of a fire and outputs a vertical angle setting signal for determining the angle of the injection nozzle of an automatic fire extinguisher (not shown) during fire extinguishing activities.

As mentioned above, depending on whether or not a predetermined number or more (two or more in the above embodiment) of adjacent light-receiving elements generate light-receiving signals of a set level or higher, the infrared ray source can determine the size and light intensity of the flame caused by a fire. In other words, it first excludes infrared rays emitted from a relatively small flame from a stove, etc., and then determines whether or not the number of pulses converted from the received light signal reaches a predetermined number within a set time. In other words, infrared rays from electric lamps, sunlight, etc. are excluded, and fire is detected in this way.

Another embodiment of the detector is shown in FIGS. 8 and 9. In the detector 22 of this embodiment, the adjusting member 23 is made of one plate, and the adjusting member 23 is disposed on the condenser lens 6 side of the light receiving element 8 so as to cover each light receiving element 8 . A large number of through holes 24 are bored in the adjustment member 23 in correspondence with each light receiving element 8, and the area of these through holes 24 increases as the distance between the light receiving element 8 and the infrared radiation source S increases. ,
It's getting bigger. That is, the incident area of the infrared rays incident on the light receiving element 8 increases as the distance between the light receiving element 8 and the infrared ray generation source S increases, and thereby the amount of incident infrared rays incident on the light receiving element 8 becomes uniform. be done.

Since this invention is configured as described above, it is possible to distinguish between the infrared rays emitted from the flames of a fire and the infrared rays emitted from various other heat sources, thereby preventing erroneous fire commands. In addition to increasing the reliability of fire detection,
Since an adjustment member is provided in the infrared incidence path to increase the incident area of the infrared rays incident from the infrared ray generation source to the light receiving element via the condensing lens as the distance between the infrared ray generation source and the light receiving element increases, If the amount of incident infrared light is made uniform regardless of the distance, and therefore the setting level is set in accordance with the uniform amount of incident light, the infrared rays will be emitted regardless of the distance between the light receiving element and the infrared source. It is possible to immediately detect whether the source is caused by a fire, and the fire detection ability can be improved.

[Brief explanation of drawings]

Fig. 1 is a front sectional view showing an embodiment of the present invention, Fig. 2 is an enlarged sectional view of the main part, Fig. 3 is a plan view of the adjustment member, and Fig. 4 shows the Fig. 5 is a block diagram showing an example of a logic circuit, Fig. 6 is a time chart of the received light signal, and Fig. 7 is the conversion of the received light signal. FIG. 8 is a front sectional view showing another embodiment of the detector, and FIG. 9 is a plan view of the adjusting member. 1, 22...detector, 2...casing, 5...
...Aperture, 6... Condensing lens, 7... Infrared filter, 8... Light receiving element, 10, 23... Adjustment member, 15... Logic circuit, 16... Waveform shaping circuit,
17...Counter.

Claims (1)

[Claims] 1. A number of infrared receiving elements are disposed within a casing having an opening in which a condensing lens and an infrared filter are mounted, and are located at a distance from the condensing lens by a converging distance, and the infrared receiving elements a detector comprising an adjusting member in an infrared incidence path that increases an incident area of infrared rays incident on the light receiving element through an optical lens as the distance between the infrared ray generation source and the light receiving element increases; The logic circuit includes a logic circuit into which a received light signal of a level corresponding to the magnitude of the amount of incident infrared light is input from each light receiving element, and this logic circuit includes a waveform shaping circuit that converts the received light signal of a set level or higher into a pulse, and a waveform shaping circuit that converts the received light signal of a set level or higher into a pulse. and a counter for counting pulses output from the circuit, and the counter is configured to output a command signal when pulses related to a predetermined number or more of mutually adjacent light receiving elements reach a predetermined number within a set time. A radiant infrared fire detection device characterized by: