JP2005250986A - Fire sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a fire sensor capable of discriminating the generation of steam by means of humidity, and preventing an erroneous report. <P>SOLUTION: This fire sensor is provided with: a fire phenomenon detecting means; and a fire judging means for judging whether or not the detection output of the fire phenomenon detecting means has reached a fire discrimination reference. The fire sensor is provided with: a humidity detecting means for detecting the humidity of an atmosphere where the fire phenomenon detecting means exists; a humidity increase judging means for judging the increase rate of humidity based on the humidity detected by the humidity detecting means; and a fire judgement reference setting means for setting the fire judgement reference of the fire judging means according to the increase rate of humidity by the humidity increase judging means. Thus, it is possible to judge the generation(arrival) of steam by the increase rate of humidity increasing according to the generation of steam, and to prevent the generation of an erroneous report due to steam. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fire detector.

  Conventionally, automatic fire alarms have been installed in ordinary buildings, and multiple fire detectors have been placed in each part of the building. A fire receiver that centrally monitors them receives fire signals and fires in the necessary areas or in the entire building. Sound an alarm.

  Such a fire detector detects heat, smoke, flame or the like in order to detect a fire, and when any of these detection levels rises, it is determined as a fire. However, these detection targets are not necessarily generated by fire, and therefore it is necessary to arrange each fire detector so as not to generate false alarms.

In addition, as a false alarm source, steam may be detected as smoke. For example, a fire detector may malfunction when it spreads from a bathroom to a ceiling surface in a private room. As a countermeasure, there is one that uses a fuzzy system to distinguish between a real fire and a non-fire, and sets the detection function as multiple elements, and sets the membership function from the case of smoking or steam as a non-fire. Has been proposed (see, for example, Patent Document 1).
JP-A-6-301870

  Such a complicated process using a fuzzy system by monitoring a fire with a plurality of elements makes a fire detector expensive and unavoidably increasing its size, making it difficult to handle. In an actual building, each part has a use and it is easy to identify a false alarm factor. Therefore, it is easy to take steam countermeasures where steam occurs.

  Accordingly, an object of the present invention is to obtain a fire detector that can determine the occurrence of steam.

  A fire detector according to claim 1 of the present invention comprises a fire detection means, and a fire detection means for determining whether or not the detection output of the fire phenomenon detection means has reached a fire determination standard. A humidity detection means for detecting the humidity of the atmosphere in which the fire phenomenon detection means exists, a humidity increase determination means for determining a rate of increase in humidity based on the humidity detected by the humidity detection means, and the humidity increase And a fire discrimination standard setting means for setting a fire discrimination standard of the fire discrimination means in accordance with a rate of increase in humidity by the discrimination means.

  According to a second aspect of the present invention, there is provided a fire detector comprising: a fire phenomenon detection means; and a fire determination means for determining whether or not a detection level of the fire phenomenon detection means has reached a fire determination standard. In the fire detector, humidity detection means for detecting the humidity of the atmosphere in which the fire phenomenon detection means exists, and a reference value of humidity as humidity in the environment is determined based on the humidity detected by the humidity detection means. The humidity increase is determined from the current humidity relative to the humidity reference value, and the humidity increase rate is determined to be large when high or low when low based on the level of the humidity reference value. And a fire discrimination standard setting unit that sets a fire discrimination standard of the fire discrimination unit in accordance with a rate of increase in humidity by the humidity rise discrimination unit.

  Furthermore, in the fire detector according to claim 3 of the present invention, the fire discrimination standard set by the fire discrimination standard setting means is the fire discrimination level and the accumulation time, or any one of them, and claim 7 of the present invention. The fire detector according to the present invention is configured such that the fire phenomenon detection means sets the output of the light receiving element based on light emission from the light emitting element to a detection level in the dark box, and the fire determination means detects smoke from the detection level. The fire is determined, and the humidity detecting means is configured to detect the humidity of the atmosphere in the dark box by disposing a humidity sensor in the dark box.

  According to a fifth aspect of the present invention, in the fire detector, the humidity increase determining means determines whether the humidity reference value is high or low from the ratio of the current humidity to the humidity reference value and the humidity saturation value to the humidity reference value. The rate of increase in humidity is taken into account.

  In the fire detector according to the first aspect, the generation (arrival) of steam is discriminated based on the rate of increase in humidity that increases with the generation of steam, and it is possible to prevent the occurrence of false alarms due to steam.

  In the fire detector according to claim 2, the generation (arrival) of steam is discriminated by the rate of increase of humidity that increases with the generation of steam, and the humidity condition of the installation environment based on the level of humidity in the environment is taken into account. This makes it possible to prevent the occurrence of misinformation due to steam.

  In the fire detector according to claim 3, in order to prevent false alarms, the fire determination level and the accumulation time may be adjusted by the rate of increase in humidity, and the fire sensor according to claim 4 has a humidity sensor in the dark box. By locating, the responsiveness of humidity detection to the output level is improved.

  In the fire detector according to the fifth aspect, since the humidity does not rise above the saturation value, it is easy to determine the rising rate of humidity relative to the environmental humidity level by determining the rate of increase in humidity based on the ratio to the saturation value.

Embodiment 1
FIG. 1 is a block circuit diagram showing a fire detector 1 according to an embodiment of the present invention.

In FIG. 1, a microcomputer (microcomputer) 10 controls the entire fire detector 1, a ROM 20 stores a program of the flowchart shown in FIG. 4, and a RAM 21 is a work area. Yes, humidity data H, humidity average value Hav, humidity increase rate ΔH, humidity stage Sh, smoke detection data AD, accumulation time C, and the like are stored.

  The EEPROM 22 stores a plurality of discrimination levels Lh, accumulation limit values Th, humidity saturation levels Hs, and the like as fire discrimination criteria.

  The light emitting circuit 30 supplies a current pulse for light emission to the light emitting element 31 when receiving a light emission control pulse from the microcomputer 10, and the amplifier circuit 40 amplifies the output level of the light receiving element 41 with a predetermined gain. Is. The signal output circuit 50 sends a signal such as a fire signal or a smoke physical quantity signal from the microcomputer 10 to a receiver (not shown). The confirmation lamp 51 is turned on when the fire detector 1 shown in FIG. 1 detects a fire, and the constant voltage circuit 60 is a circuit that supplies a constant voltage to the microcomputer 10.

  The humidity detector 70 detects the humidity inside the dark box 84 of the fire detector 1 shown in FIG. 2, and as shown in FIG. 1, a humidity sensor 71, a thermistor 72 using a polymer that responds to humidity, and An output circuit 73 is used.

  The light emitting circuit 30 and the amplifier circuit 40 are examples of fire phenomenon detection means. The microcomputer 10 is an example of fire discrimination means. The humidity detection unit 70 is an example of a humidity detection unit, and the microcomputer 10 is also an example of a humidity increase determination unit and a fire determination reference setting unit.

  FIG. 2 is a vertical cross-sectional view of the fire detector 1 according to an embodiment of the present invention fitted in the base 2, and FIG. 3 is a cross-sectional view showing the inside of the dark box 84 of the fire detector 1. It is.

  In FIG. 2, the main body of the fire detector 1 has an outer shape formed by a base 81 and a back cover 82, and a printed circuit board 83 on which a circuit element such as a microcomputer (not shown) is mounted is disposed. The light emitting element 31 and the light receiving element 41 connected to the printed circuit board 83 are provided in the dark box 84, and a humidity sensor 71 is further provided.

  As shown in FIG. 3, the dark box 84 has a structure in which outside light is blocked by a labyrinth structure with a plurality of walls 85 formed in a cylindrical shape, and at the same time, a passage that allows inflow of smoke together with outside air is formed. The light-emitting element 31 and the light-receiving element 41 are disposed in a position where the light-emitting element 31 and the light-receiving element 41 do not face each other. The light-receiving element 41 does not directly receive the light from the light-emitting element 31 and It is designed to receive scattered light.

  The humidity sensor 71 is arranged in the dark box 84, so that when the steam instead of smoke enters the dark box 84 and the light receiving element 41 detects scattered light, the humidity sensor 71 simultaneously increases the humidity. Can be detected. As described above, the humidity sensor 71 is arranged so as to lie on the surface of the smoke detection area 86 outside the field of view of the light receiving element 31 in the dark box 84. Humidity output that responds to output is possible.

  Next, the operation of the above embodiment will be described.

  FIG. 4 is a flowchart showing an operation executed by the microcomputer 10 in the embodiment.

  First, initial processing at power-on is performed (S1), a sampling period (for example, about 3 seconds) is taken, and when a time is up by a CR circuit (or an oscillation circuit) (not shown) (S2), although not described in detail, Power is supplied to a place where the amplifier circuit 40 of the element 41 or the like is not energized at all times (S3), and preparations for taking in various data are made. Here, the reason why the amplifier circuit 40 and the like are energized only during sampling is to reduce current consumption.

  Then, the microcomputer 10 performs A / D conversion on the output from the humidity detector 70 as humidity data H (S4), and calculates the humidity average value Hav as a humidity reference level (S5). The humidity average value Hav is stored in the RAM 21 as humidity data H for the past one minute as a predetermined time (20 times as a period of about 3 seconds), and the average value is calculated as the humidity average value Hav. Since the humidity average value Hav is an average for a predetermined time, even if steam is generated, the humidity average value Hav does not increase immediately, and can represent a numerical value as humidity in a stable environment. Therefore, for example, it is high in summer and low in winter.

Next, the humidity increase rate ΔH is calculated (S6). The humidity increase rate ΔH may be a difference between the humidity average value Hav and the latest humidity data H, but the humidity average value Hav varies depending on the season, and the level of the influence of steam is large or small. . Accordingly, the humidity saturation level Hs corresponding to the humidity data H in a state where the humidity is saturated is stored in the EEPROM 22, and the difference from the humidity average value Hav as the humidity in the environment to the humidity saturation level Hs is stored. The ratio of how much the current humidity data H has increased is the humidity increase rate ΔH. Therefore, it is possible to determine in common a small increase in the humidity of the eyes due to steam when the humidity in the environment is high and a large increase in the humidity of the eyes due to steam when the humidity in the environment is low.

Next, the humidity level Sh for the humidity increase rate ΔH is determined and stored in the RAM 21 (
S7). The humidity level Sh referred to here is a step division from a state where there is no steam to a state where there is certain steam, and can be divided into, for example, three stages based on the humidity increase rate ΔH. The presence of steam is determined based on the output from the humidity detection unit 70 in such a procedure (from S4 to S7).

  Then, the light emission circuit 30 is triggered to A / D convert the output of the sample hold circuit 22 to capture the smoke detection data AD (S8), store in the RAM 21, and then correspond to the humidity stage Sh stored in the RAM 21. The fire discrimination level Lh is read (S9), and the smoke detection data AD is compared with the fire discrimination level Lh (S10). In the normal state, the fire determination level Lh is, for example, 5% / m, and the smoke detection data AD does not exceed the fire determination level Lh. Then, the accumulation time is reset to “0” (S11), and although not described in detail, the microcomputer 10 enters a stop state (or sleep state), takes a cycle, and at the next time up (S2), Will be activated.

  Next, when a fire occurs, the smoke detection data AD captured by A / D converting the output of the sample hold circuit 22 in the flowchart of FIG. 4 becomes a large value based on the occurrence of a fire (S8). ). Then, the smoke detection data becomes larger in comparison with the fire discrimination level Lh (S10), and the accumulation time C is counted (S12).

  If the accumulation time C does not exceed the accumulation limit value Th corresponding to the humidity stage Sh stored in the RAM 21 (S14), the microcomputer 10 is in the stop state as in the normal state, and the time is up (S2). I will wait. As the smoke detection data AD continues to exceed the fire discrimination level Lh, the accumulation time C increases (S12). In the normal state, the accumulation is set to a predetermined value of about 10 to 50 seconds. When the accumulation time C exceeds the limit value Th, the microcomputer 10 determines that there is a fire (S14), and performs a fire alarm operation (S15). For this fire alarm operation, the microcomputer 10 activates the signal output circuit 50 to perform a switching operation, outputs a fire signal to a fire receiver (not shown) via a signal line, and controls lighting of the confirmation 51 or the like. The fire detector 1 displays that a fire has been detected. In addition, about this fire alerting | reporting operation | movement, operation | movement required as a fire alerting | reporting installation is performed, and operation | movement changes according to the installation.

Next, the case where high humidity is detected simultaneously with the generation of steam will be described. In the flowchart of FIG. 4, the humidity data H taken from the humidity detector 70 has a high value (S4), and the humidity average value Hav is calculated. Later (S5) the calculated humidity increase rate ΔH increases (S
6) As a result, the humidity level Sh for the humidity increase rate ΔH is stored in the RAM 21 as a level where steam is present (S7).

  When steam is generated, the smoke detection data AD obtained by A / D converting the output of the sample hold circuit 22 becomes a large value as in the case of smoke due to fire (S8). In contrast between the smoke detection data AD and the fire determination level Lh (S10), if the humidity level Sh stored in the RAM 21 is at a high level, the fire determination level Lh is also high (for example, 1.5 in the normal state). Is set so as not to easily exceed the fire discrimination level Lh. First, at the stage of comparison between the smoke detection data AD and the fire discrimination level Lh, it is difficult to discriminate a fire due to steam.

  Even if the smoke detection data AD due to steam exceeds the fire discrimination level Lh which is higher than normal, the accumulation limit value Th corresponding to the high humidity stage Sh stored in the RAM 21 is the same as the fire discrimination level Lh. A long time (for example, 1.5 times the normal state) is set (S13), and the accumulation time C is set so as not to easily exceed the accumulation limit value Th. As described above, similarly to the fire discrimination level Lh, it is difficult to discriminate a fire due to steam even at the stage of comparison between the accumulation time C and the accumulation limit value Th.

  As described above, the fire discrimination level Lh and the accumulation limit value Th, which are fire discrimination criteria, are set to be difficult to discriminate from fire, thereby preventing misinformation due to steam. Because of this, fire alarms based on humidity data are not prohibited at all. Such a fire discrimination standard may be set to either the fire discrimination level Lh or the accumulation limit value Th, and in that case, it is necessary to make the tendency more prominent than when both are used. Note that steam is often a temporary cause of misinformation and it is difficult to maintain steam. For this reason, it is possible to spend time until discrimination by setting the discrimination level and accumulation redundancy, thereby preventing false reports.

  As mentioned above, it has been explained about steam countermeasures when detecting smoke as the fire detector 1, but it is not necessarily smoke, and even when detecting heat, misinformation may occur from the heat accompanying steam, In the case of a heat detector, the fire discrimination criteria can be changed in the same manner to prevent misreporting due to steam.

  Further, although the humidity level Sh is set in multiple stages based on the humidity data H from the humidity detection unit 70, the normal fire discrimination level and accumulation limit value, and the fire at the time of humidity detection are simply determined as the necessity of measures against humidity. The determination level and the accumulation limit value may be switched.

For such a fire detector 1 that outputs a fire signal based on the detection of a fire, a so-called analog fire detector that encodes the detected smoke density and transmits it as analog data to a fire receiver. There is. In the case of an analog fire detector, the fire detection is not performed by itself (in this case, the fire receiver side), but the smoke concentration as this analog data is detected when the humidity rise rate is large. This is equivalent to setting the fire discrimination standard (in this case, the discrimination level) by sending the signal down to 2/3. Moreover, sending out the smoke density immediately before the occurrence of the humidity rise for a predetermined time corresponding to the extension of the accumulation time also corresponds to setting the fire discrimination standard. Furthermore, the present invention is not limited to such an analog type, and is a stop means for transmitting a signal in a subsequent state by simply transmitting a zero level or stopping a fire signal output for a predetermined time even when a fire signal is transmitted. Also, it is possible to prevent the occurrence of misinformation due to steam.

Experimental Example Next, an experimental example on the influence of steam on the fire detector 1 will be described.

  FIG. 5 is an explanatory diagram relating to the experimental method, and FIG. 6 is a graph showing an output based on the experiment.

  In FIG. 5, although not shown, the fire detector 1 is provided with humidity sensors inside and outside the housing, and the humidity sensor inside the humidity sensor is contained in the dark box 84 as shown in FIGS. 71 is attached. The fire detector 1 is installed on a plate-like mounting base 97 formed obliquely from the upper surface of a desk 96, and a steam-type humidifier 98 is disposed below the fire detector 1. And the drawer 99 is arrange | positioned so that the fire detector 1 located above the humidifier 98 may be interrupted | blocked, The drawer | drawer 99 can be taken in / out.

  The smoke detection output of the fire detector 1 and the outputs of both humidity sensors are connected to a logger (not shown) so that data can be collected.

  The steam generated from the humidifier 98 is applied to the fire detector 1 and the data is recorded. Ten seconds after the humidifier 98 is started, the drawer 99 is accommodated in the desk 96 and the fire is detected. Steam was applied to the vessel 1. The temperature in the experiment environment was about 22 ° C. and the humidity was 30%.

  In FIG. 6, the vertical axis is the output of both humidity sensors on the left side, the smoke detection output of the fire detector 1 is on the right side, the horizontal axis is the elapsed time, and the curve A is the humidity sensor outside the fire detector 1. The output, curve B is the output of the humidity sensor in the dark box 84 of the fire detector 1, and curve C is the smoke detection output of the fire detector 1. When the elapsed time in this graph was 10 seconds, the drawer 99 was housed in the desk 96 and steam was applied to the fire detector 1.

  As a result, when the curve C is seen, it can be understood that the smoke detection output of the fire detector 1 rises about 10 seconds after the steam is applied, and that false alarm can be caused by the steam. As with the rise of the smoke detection output due to steam, both the curve A and the curve B rise rapidly, but the rise position of the curve B is almost the same as that of the curve A due to the difference in the arrangement inside and outside the dark box 84. From this result, it can be confirmed that the humidity increases with the increase of the smoke detection output due to steam, and it is preferable to detect the humidity in the dark box 84 in terms of responsiveness to the smoke detection output. I understand that.

1 is a block circuit diagram of a fire detector showing Embodiment 1 of the present invention. The longitudinal cross-sectional view of the fire detector of FIG. The cross-sectional view which shows the inside of the dark box of the fire detector of FIG. The flowchart which shows operation | movement of the fire detector of FIG. Explanatory drawing regarding the experiment example of this invention. The graph which shows the data based on the experiment example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fire detector 10 Microcomputer 30 Light emission circuit 40 Amplification circuit 70 Humidity detection part 71 Humidity sensor 84 Dark box

Claims (5)

In a fire detector comprising a fire phenomenon detection means and a fire detection means for determining whether or not the detection output of the fire phenomenon detection means has reached a fire determination standard,
Humidity detecting means for detecting the humidity of the atmosphere in which the fire phenomenon detecting means exists; and
Humidity increase determining means for determining a rate of increase in humidity based on the humidity detected by the humidity detecting means;
Fire discrimination criterion setting means for setting a fire discrimination criterion of the fire discrimination means according to the rate of increase in humidity by the humidity rise discrimination means;
A fire detector characterized by comprising: In a fire detector comprising a fire phenomenon detection means and a fire detection means for determining whether or not the detection level of the fire phenomenon detection means has reached a fire determination standard,
Humidity detecting means for detecting the humidity of the atmosphere in which the fire phenomenon detecting means exists; and
Based on the humidity detected by the humidity detecting means, a reference value of humidity as humidity in the environment is determined, a rate of increase in humidity is determined from the current humidity relative to the reference value of the humidity, and the humidity Humidity increase determination means for determining an increase rate based on the level of the humidity reference value, which is large when high or small when low.
Fire discrimination criterion setting means for setting a fire discrimination criterion of the fire discrimination means according to the rate of increase in humidity by the humidity rise discrimination means;
A fire detector characterized by comprising:   The fire detector according to claim 1 or 2, wherein the fire discrimination standard set by the fire discrimination standard setting means is a fire discrimination level and / or an accumulation time. The fire phenomenon detection means sets the output of the light receiving element based on the light emission from the light emitting element to a detection level in the dark box, and the fire determination means determines fire by detecting smoke from the detection level. And
The fire detector according to claim 1, wherein the humidity detecting means is configured to detect a humidity of an atmosphere in the dark box by disposing a humidity sensor in the dark box. 3. The fire detection according to claim 2, wherein the humidity rise determination means uses a ratio of the current humidity with respect to the humidity reference value and a humidity saturation value with respect to the humidity reference value as a humidity increase rate that takes into account the level of the humidity reference value. vessel.

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