JP5416391B2 - smoke detector - Google Patents

Description

  The present invention relates to a smoke detector that detects and reports smoke generated during a fire.

  Conventionally, as this kind of smoke detector A, there is a detection space X in the housing 20 as shown in FIG. 4, and an LED (light emitting part) 7 that outputs light intermittently toward the detection space X; A device including a photodiode (light receiving unit) PD that is disposed at a position where direct light from the LED 7 is not incident and converts received light into current is known. In this smoke detector A, when smoke flows into the detection space X, the light from the LED 7 is diffused and reflected by the smoke in the detection space X, thereby increasing the amount of light received from the LED 7 at the photodiode PD. The amount of current output from the photodiode PD increases according to the smoke density (see, for example, Patent Document 1).

  In this type of smoke detector A, a detection processing unit that obtains a detection value corresponding to the smoke density in the detection space X based on the received light intensity of the photodiode PD in the detection circuit 1 housed in the housing 20; A determination processing unit that compares the detected value with a predetermined fire determination level is provided. And if a detection value is more than a fire determination level, it will determine with the smoke density | concentration in the detection space X being more than a regulation value, and it is comprised so that generation | occurrence | production of a fire may be reported.

  By the way, in the smoke detector A having the above-described configuration, the detection value is increased not only by the smoke flowing into the detection space X but also by dirt such as dust accumulated on the inner peripheral surface of the detection space X. That is, when dirt is attached to the inner peripheral surface of the detection space X, the light from the LED 7 is diffusely reflected by the dirt and received by the photodiode PD, leading to an increase in the detection value. In this case, since the measured detection value is higher than the value corresponding to the actual smoke density, the detection value reaches the fire judgment level even though the smoke density in the detection space X is less than the specified value, and the May generate a fire (so-called non-fire report).

  Therefore, in the invention described in Patent Document 1, when determining the presence or absence of smoke in the detection space X, a contamination state level that is a change amount of a detection value caused by contamination in the detection space X is detected, and the contamination is detected. A configuration is adopted in which correction is performed by subtracting the state level from the detection value, and fire determination (determination of presence / absence of smoke) is performed based on the detection value after correction.

  However, in the invention described in Patent Document 1, the process of detecting the dirt state level and the process of fire determination are performed separately, and each time a fire determination is made, the dirt state level is detected and the dirt state level is detected. Therefore, there is a problem in that the number of processes necessary for fire determination increases.

On the other hand, as the smoke detector A, there has been proposed a device having a function of determining the state of the detection space X as described above, such as the presence or absence of contamination or the presence or absence of a failure of the smoke detector A itself, as an operating state. Yes. In the smoke detector A, the user can check various operation states in addition to the presence or absence of a fire, so appropriate measures (correction of detection values, repair of the smoke detector, etc.) based on these operation states )It can be performed.
JP 10-334363 A

  However, this type of smoke detector A requires a circuit for determining various operating states separately from the circuit for determining fire, so that the circuit configuration becomes complicated, and the process for determining the operating state is a fire determining process. Since the process is performed separately from the process, the problem is that the time required for the determination becomes longer than when only the fire determination is performed.

  The present invention has been made in view of the above reasons, and the circuit configuration is complicated or the time required for the determination is longer than when only the fire determination is performed while determining the operation state other than the presence or absence of the fire. It is an object to provide a smoke detector that does not become unusable.

In the first aspect of the present invention, the light emitting unit intermittently outputs light toward the detection space, and the light from the light emitting unit diffusely reflected by the smoke that does not enter the direct light from the light emitting unit and flows into the detection space. A light receiving unit arranged at a position where light is incident, a detection processing unit that obtains a detection value corresponding to the smoke density in the detection space based on the light reception intensity at the light receiving unit, and the presence or absence of a fire based on the detection value A determination processing unit that includes a storage unit that stores a plurality of determination levels, and a determination unit that compares the detection value with the determination level. The determination level is smoke in the detection space. Use at least one of the reference level corresponding to the detected value when there is no fire, the fire judgment level set higher than the reference level and used as a fire judgment standard, and the reference level and fire judgment level set lower than the fire judgment level Calculated after the fire A state determination level that is a determination criterion for the predetermined state, the state determination level includes a failure determination level set lower than the reference level, and a dirt determination level set higher than the reference level, The determination means determines a fire if the detection value is equal to or higher than a fire determination level in one process of comparing the detection value with the determination level, and determines a failure if the detection value is less than the failure determination level. If the detection value is equal to or higher than the dirt determination level and lower than the fire determination level, it is determined that the detection space is dirty.

According to this configuration, the determination unit determines that the fire is detected if the detection value is equal to or higher than the fire determination level, and is predetermined according to the magnitude relationship between the detection value and the state determination level if the detection value is less than the fire determination level. since determining the state can be determined both the state other than the presence or absence and fire a fire in comparison to a single process the detection value and the determination level. Therefore, there is an advantage that the circuit configuration is not complicated and the time required for the determination does not become longer than when only the fire determination is performed while determining the operation state other than the presence or absence of the fire.

Further , according to this configuration, when the detected value is out of the normal range due to an abnormality in the optical system or the like, it can be determined that there is a failure. Furthermore, the determination means can determine the presence or absence of dirt in the detection space by using the dirt judgment level.

According to a second aspect of the present invention, in the first aspect of the invention, the failure determination level is calculated using the reference level.

  According to this configuration, there is an advantage that it is not necessary to set the failure determination level independently, and the time and effort for setting the determination level can be saved.

The invention according to claim 3, in the invention of claim 1 or claim 2, pre-Symbol judging means, if there a determination dirt on the confirmation to the specified value or more frequently the presence of dirt Jo Tokoro timing, Correction for increasing the fire determination level in the storage means is performed.

  According to this configuration, the presence / absence of contamination is confirmed at a predetermined timing, and if it is determined that contamination is present at a frequency more than a specified value, the fire determination level in the storage unit is corrected to increase, so a fire determination is performed. The frequency of correction is lower than that of a conventional configuration in which subtraction correction needs to be performed every time. Therefore, there is an advantage that the processing necessary for the fire determination can be reduced as compared with the prior art while preventing the non-fire report due to the contamination in the detection space.

The invention of claim 4 is characterized in that, in the invention of claim 3 , the contamination determination level is calculated using both the reference level and the fire determination level.

  According to this configuration, there is an advantage that it is not necessary to set the stain determination level independently, and the time for setting the determination level can be saved. Also, since the dirt judgment level is calculated using the fire judgment level, when the fire judgment level is corrected, the dirt judgment level is also corrected, and it is not necessary to correct the dirt judgment level when the detection space is dirty. become.

The present invention, the determination means, since the determination of both the state of non-existence and fire a fire in comparison to a single process the detection value and the determination level, while determining the status of the non-existence of a fire, Compared with the case where only fire determination is performed, there is an advantage that the circuit configuration is not complicated and the time required for determination does not increase.

(Embodiment)
The smoke detector A of the present embodiment has a detection space X in the housing 20 as in the conventional configuration shown in FIG. 4, and an LED (light emitting unit) that outputs light intermittently toward the detection space X 7, a photodiode (light receiving unit) PD that is arranged at a position where direct light from the LED 7 is not incident and converts received light into current, and detects smoke in the detection space X based on the input current from the photodiode PD The detection circuit 1 is provided. In this smoke detector A, when smoke flows into the detection space X, the light from the LED 7 is diffused and reflected by the smoke in the detection space X, thereby increasing the amount of light received from the LED 7 at the photodiode PD. The amount of current output from the photodiode PD increases. The smoke detector A exemplified here uses a battery as a power source, and is intermittently driven in order to reduce the average power consumption and extend the life of the battery.

  As shown in FIG. 1, the detection circuit 1 according to the present embodiment includes a detection processing unit 2 that obtains a detection value corresponding to the smoke density in the detection space X based on an input current input from the photodiode PD, and a detection process. And a determination processing unit 3 that is provided at a subsequent stage of the unit 2 and determines the presence or absence of a fire based on the detection value.

  As shown in FIG. 1, the detection processing unit 2 converts an input current input from an input terminal into an output voltage whose voltage value varies according to the variation of the input current, and outputs the output voltage (I / V). V converter circuit 4, a voltage amplifier circuit 5 that is connected to the output of the current-voltage converter circuit 4 and amplifies the output voltage, and an AD converter that converts the output of the voltage amplifier circuit 5 (hereinafter referred to as an output signal) into a digital value. And 6. The AD converter 6 samples (samples) the output signal and quantizes it, so that the fluctuation component (detection value) of the output signal caused by the photodiode PD receiving the light from the LED 7 is converted into a digital value. Extract. According to this configuration, the detection processing unit 2 uses the instantaneous value of the output signal when the input current from the photodiode PD is zero as the operating point, and the change of the output signal from the operating point according to the fluctuation of the input current. The quantity is output as a detection value to the determination processing unit 3 at the subsequent stage.

  The determination processing unit 3 includes a storage unit 8 that stores a determination level, which will be described later, and a determination circuit 10 that serves as a determination unit that determines the presence or absence of smoke in the detection space X based on the output (detection value) of the AD converter 6. Have The determination circuit 10 determines the presence or absence of smoke in the detection chamber X by comparing the detection value with a predetermined determination level in the storage means 8.

  Here, the determination level stored in the storage means 8 includes a predetermined reference level (corresponding to a detection value when there is no smoke in the detection space X) and a reference level as shown in FIG. A fire determination level that is set higher than the fire determination level and a state determination level that is set lower than the fire determination level and serves as a determination reference for a predetermined operation state other than the fire is included. The determination circuit 10 determines both the presence / absence of a fire and the operating state simultaneously by comparing the magnitude relationship between the detection value and each determination level.

  In the present embodiment, the state determination level is set higher than the reference level, and includes a contamination determination level that is a determination criterion when determining the presence or absence of contamination in the detection space X as an operation state. That is, as shown in FIG. 3, the determination circuit 10 compares the detection value with each determination level to determine a region corresponding to the detection value (S1), and a region B (FIG. 3) where the detection value is equal to or higher than the fire determination level. 2) (S3: Yes), it is determined that there is smoke in the detection space X (the smoke concentration has reached a level that can be determined as a fire), and the detected value is greater than or equal to the contamination determination level and less than the fire determination level (S4: Yes), it is determined that there is dirt in the detection space X.

  Further, in the present embodiment, the state determination level includes a failure determination level that is set lower than the reference level and serves as a determination reference when determining the failure of the smoke detector A as the operation state. The determination circuit 10 determines that the detection value is normal when the detection value corresponds to the region A (see FIG. 2) that is equal to or higher than the failure determination level and lower than the contamination determination level (S2: Yes), and the detection value is lower than the failure determination level. When it corresponds to D (see FIG. 2) (S4: No), it is determined as a failure. As a result, when the detected value deviates from the normal range due to an abnormality in the optical system, it can be determined that there is a failure.

  However, here, instead of issuing a report or the like by a single determination, various counters are operated in accordance with the areas A to D to which the detected value corresponds, and the alarm is issued when the count value reaches a specified value. Etc. shall be performed.

  More specifically, when the detected value corresponds to the region B, the fire determination counter is operated every time it is determined that the detected value corresponds to the region B (S5), and the count value becomes the specified value. When it reaches (S6: Yes), it is determined that there is smoke and fire alarm is started (S7). When the detected value corresponds to the region D, the failure determination counter is operated every time it is determined that the detected value corresponds to the region D (S8), and if the count value reaches the specified value (S9: Yes). ), The determination of failure is confirmed, and failure notification is started (S10).

  When the detected value corresponds to the region C, the stain determination counter is operated every time it is determined that the detected value corresponds to the region C (S11), and when the count value reaches the specified value (S12). : Yes), the determination that there is dirt is fixed, and correction is performed to increase the fire determination level in the storage means 8 (S13). That is, in the smoke detector A, light from the LED 7 is diffused and reflected by not only the smoke flowing into the detection space X but also dirt such as dust accumulated on the inner peripheral surface of the detection space X, and the photodiode PD. When it is determined that dirt is attached in the detection space X so that a non-fire report is not generated due to an increase in the detection value due to dirt. Make corrections to raise the fire detection level. At this time, the correction amount (lift amount) of the fire determination level is determined according to the detection value excess amount (difference between the detection value and the contamination determination level) from the contamination determination level.

  By the way, the comparison (S1) between the detection value in the determination circuit 10 and each determination level is performed in a predetermined cycle (for example, a cycle of 8 seconds). However, since the dirt in the detection space X does not adhere in a short time, whether or not the detected value corresponds to the region C is determined every predetermined correction cycle (for example, 1 hour). And That is, at a timing other than the correction cycle, even if it is determined that the detected value falls within the region C, the contamination determination counter is not operated and it is determined normal. In addition, when the detection value falls in a region other than the region C in the correction cycle, the count value of the dirt determination counter decreases by down-counting. Accordingly, the determination circuit 10 confirms the presence or absence of dirt (that is, whether or not the detected value corresponds to the region C) at each correction cycle, and has a frequency equal to or higher than a specified value (for example, 8 times out of 10). If it is determined that there is dirt (that is, the detected value corresponds to the region C), a correction for increasing the fire determination level in the storage unit 8 is performed.

  Further, in the present embodiment, when the determination circuit 10 determines that there is smoke, the period of comparison determination between the detection value in the determination circuit 10 and each determination level (hereinafter referred to as a determination period) is made shorter than in the steady state. Thus, the time from when the smoke flows into the detection space X until the fire is triggered is shortened. That is, when the detected value corresponds to the region B and the fire determination counter starts operating, the determination cycle is changed to be shorter (for example, changed from an 8-second cycle to a 4-second cycle).

  As a specific example, a counter capable of counting from 0 to 5 is used as a fire determination counter, and when the detection value falls within the region B, the determination cycle is shortened when the count value changes from “0” to “1”. It is possible to do. In this case, the count value is “1” to “2” because the detection value corresponds to the region B at the next determination, and the count value is “2” because the detection value corresponds to the region B at the next determination. When “3” is reached, fire alarm is started. Thereafter, the count value “3” is maintained while the detected value falls within the region B, and when the detected value deviates from the region B, the count value is set to “4”, “5”, “0” for each determination. Change in the order. While the count value is “4” and “5”, the fire alarm is continued, but when the count value returns to “0”, the fire alarm is terminated and the determination period is changed to the original determination period (for example, 4 Change from a second period to an eight-second period).

  Further, the determination circuit 10 calculates a state determination level (dirt determination level and failure determination level) using at least one of the reference level and the fire determination level, and stores the calculated state determination level in the storage unit 8. It has a function as a calculation means. That is, only the reference level and the fire determination level are set in advance, for example, before shipment from the factory, and the state determination level (dirt determination level and failure determination level) is automatically calculated by the determination circuit 10 as the determination level. It becomes.

  Here, when the reference level is AD0 and the fire determination level is ADF, the contamination determination level is defined as (ADF−AD0) / 4 + AD0, and the failure determination level is defined as (AD0) / 2. As a result, there is an advantage that it is not necessary to individually set the fire determination level and the failure determination level, and the labor for setting the determination level can be saved. In addition, when the dirt judgment level is calculated using the fire judgment level as described above, the dirt judgment level is corrected along with the correction of the fire judgment level when the judgment that there is dirt is confirmed. Therefore, there is an advantage that it is not necessary to correct the dirt determination level when the detection space X is dirty. In short, when the determination that there is contamination is confirmed and the fire determination level is increased, the contamination determination level calculated from the fire determination level is also automatically increased. In addition, it is possible to set the dirt determination level and the failure determination level relatively flexibly, such as changing the dirt determination level and the failure determination level according to the installation environment of the smoke detector A.

  Note that how to define the dirt determination level and the failure determination level is not limited to the above-described ones. In general, the magnitude of the detection value is caused by the temperature characteristics of the circuit components. Since a variation of about 10% is expected, it is desirable that the failure determination level be 80% or less of the reference level so that a failure is not determined due to the variation.

  The determination result in the determination circuit 10 is sent to a notification circuit (not shown), and is appropriately selected when a fire occurs (that is, when it is determined that there is smoke) or when a failure is determined (that is, when it is determined that there is a failure). It is notified by the method. The smoke detector A may be configured to send the determination result to an external device such as a home information board.

  According to the configuration described above, the determination circuit 10 compares the detection value with a plurality of determination levels stored in the storage unit 8 to determine the presence or absence of smoke in the detection space X, and the operation. Both the process for determining the state (presence / absence of contamination in the detection space X and the presence / absence of failure) can be performed simultaneously in a single process, and the process for determining the operating state and the process for determining the fire as in the past are performed. The processing time can be shortened as compared with the case where it is performed separately. In addition, the determination circuit 10 confirms the presence or absence of dirt at every predetermined correction cycle, and performs correction to increase the fire determination level if it is determined that there is dirt at a frequency equal to or higher than a specified value. As compared with the conventional configuration in which the contamination level needs to be subtracted from the detection value each time the correction is performed, the frequency of correction is reduced, and the number of arithmetic processes associated with the correction can be reduced. As a result, while preventing non-fire information due to contamination in the detection space X, it is possible to reduce the number of processes necessary for determining the presence or absence of smoke in the detection space X compared to the conventional case.

  In addition, some conventional smoke detectors use individual circuits for each judgment type in order to make various judgments (failure judgment, dirt judgment, etc.) other than fire judgment. Compared with such a conventional configuration, there is an advantage that the circuit configuration is simplified and the smoke detector A is reduced in size and power consumption.

  Note that the contamination in the detection space X (whether or not the detection value corresponds to the region C) is not limited to the configuration that is determined at each predetermined correction period as described above, but for example, the smoke detector A The determination may be made at an appropriate timing such as at the time of periodic inspection, and if it is determined that there is contamination at a frequency equal to or higher than a specified value, a correction may be made to increase the fire determination level in the storage unit 8.

It is a schematic block diagram which shows the detection circuit of embodiment of this invention. It is explanatory drawing which shows the determination level used for the same as the above. It is a flowchart which shows operation | movement same as the above. It is a schematic block diagram which shows the conventional smoke detector.

Explanation of symbols

2 detection processing unit 3 determination processing unit 8 storage unit 10 determination circuit (determination unit)
A Smoke detector X Detection space

Claims (4)

A light emitting unit that intermittently outputs light into the detection space and a position where light from the light emitting unit diffused and reflected by the smoke flowing into the detection space does not enter the direct light from the light emitting unit. A detection processing unit that obtains a detection value corresponding to the smoke density in the detection space based on the received light intensity at the light reception unit, and a determination processing unit that determines the presence or absence of a fire based on the detection value The determination processing unit includes a storage unit that stores a plurality of determination levels, and a determination unit that compares the detection value with a determination level. The determination level is a detection value in a state where there is no smoke in the detection space. Is calculated using at least one of the reference level and the fire judgment level that is set lower than the fire judgment level and the fire judgment level that is set higher than the reference level and becomes the fire judgment standard. Judgment status And a state determination level becomes quasi,
The state determination level includes a failure determination level set lower than the reference level, and a dirt determination level set higher than the reference level,
The determination means determines a fire if the detection value is equal to or higher than a fire determination level in one process of comparing the detection value with the determination level, and determines a failure if the detection value is less than the failure determination level. If the detected value is not less than the dirt determination level and less than the fire determination level, it is determined that there is dirt in the detection space.   The smoke detector according to claim 1, wherein the failure determination level is calculated using the reference level.   The determination means confirms the presence or absence of dirt at a predetermined timing, and performs correction to increase the fire judgment level in the storage means if it is determined that dirt is present at a frequency more than a specified value. The smoke detector according to claim 1 or 2.   The smoke detector according to claim 3, wherein the contamination determination level is calculated using both the reference level and the fire determination level.

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