Smoke detection device
By using the signal ratio adjustment technology of polarized light and multiple light-receiving parts in the smoke detection device, the problem of degradation of smoke type determination accuracy caused by deterioration of the light-receiving element is solved, and the correct smoke type determination in the case of deterioration is achieved.
Patent Information
- Application Number
- CN202380041432.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-06-09
- Filing Date
- 2023-06-06
- Publication Date
- 2024-12-31
AI Technical Summary
When the light-receiving element deteriorates over the years or deposits in dirt, the existing dual-light-receiving smoke detection device cannot correctly determine the type of smoke, resulting in a decrease in detection accuracy.
A smoke detection device is adopted, and polarized light is emitted by the light emitting part. The first light receiving part and the second light receiving part receive polarized light respectively, and the multiplication rate is determined based on the ratio of the two signals, and used to adjust the amplitude value of the signal to ensure correct judgment. Types of smoke.
Even in the case of deterioration or decontamination over the years, the type of smoke can be correctly determined, which improves detection accuracy and reliability.
Smart Images
Figure CN119234141A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a device for detecting smoke. Background Art
[0002] There is a smoke detection device that detects the generation of smoke in a monitored space by detecting smoke contained in the monitored space. As one type of smoke detection device, there is a so-called photoelectric type. The photoelectric smoke detection device detects smoke based on a signal generated when a light receiving unit receives reflected light generated by light emitted from a light emitting unit reflected by smoke particles in the air flowing from the outside into a container that accommodates the light emitting unit and the light receiving unit.
[0003] As another type of photoelectric smoke detection device, there is a so-called dual-light-receiving type. The dual-light-receiving type smoke detection device emits polarized light in the direction of the light-emitting axis from the light-emitting unit, and determines the type of smoke in the air based on the signals generated by two light-receiving units having light-receiving axes intersecting the light-emitting axis from different directions.
[0004] As a patent document that discloses a dual-light-receiving type smoke detection device, there is Patent Document 1, for example.
[0005] Prior art literature
[0006] Patent Literature
[0007] Patent Document 1: Japanese Patent Application Publication No. 2011-203889 Summary of the invention
[0008] Problems to be solved by the invention
[0009] Due to individual differences in the light-receiving elements of the light-receiving unit, the amplitude value of the signal generated by the light-receiving unit when receiving light of the same intensity varies from product to product. Therefore, the photoelectric smoke detection device usually calculates the multiplier obtained by dividing the reference amplitude value by the amplitude value of the signal generated by the light-receiving unit under the reference environment before shipment. When in use, the value obtained by multiplying the amplitude value of the signal generated by the light-receiving unit by the calculated multiplier is used as the output value of the light-receiving unit. As a result, in any product, the output value of the light-receiving unit under the reference environment represents the reference intensity. As a result, for example, by comparing the output value of the light-receiving unit with a specified threshold value, any smoke detection device can detect smoke with the same sensitivity.
[0010] Generally, when a smoke detection device is used, the output value of the light receiving unit changes slowly due to the degradation of the light receiving element over time, the accumulation of dirt on the light emitting unit and the light receiving unit, etc. As described above, a dual light receiving type smoke detection device determines the type of smoke in the air based on the signals generated by each of the two light receiving units. Therefore, when the output values of each of the two light receiving units change due to degradation over time, etc., the smoke detection device may not be able to correctly determine the type of smoke.
[0011] In view of the above circumstances, an object of the present invention is to provide a dual-light-receiving type smoke detection device that can accurately determine the type of smoke even if it has deteriorated over time.
[0012] Means for solving problems
[0013] In order to solve the above-mentioned problems, the present invention proposes a smoke detection device, which comprises: a light-emitting unit, which emits polarized light; a first light-receiving unit, which has a first light-receiving axis intersecting with the light-emitting axis of the light-emitting unit; a second light-receiving unit, which has a second light-receiving axis intersecting with the light-emitting axis of the light-emitting unit and in a different direction from the first light-receiving axis; and a smoke determination unit, which detects smoke in the air based on a signal generated by the first light-receiving unit during the period when the light-emitting unit emits light, and, when smoke is detected, determines the type of smoke in the air based on the signal generated by the first light-receiving unit during the period when the light-emitting unit emits light and the signal generated by the second light-receiving unit during the period when the light-emitting unit emits light. type; and a multiplication factor determination unit, which determines a multiplication factor to be multiplied with at least one of the signal generated by the first light receiving unit and the signal generated by the second light receiving unit in such a manner that a ratio of an amplitude value of a signal generated by the second light receiving unit during a period when the light emitting unit emits light relative to an amplitude value of a signal generated by the first light receiving unit during a period when the light emitting unit emits light becomes a predetermined value during a period when the smoke determination unit does not detect smoke in the air, and the smoke determination unit determines the type of smoke in the air based on a value obtained by multiplying the amplitude value of at least one of the signal generated by the first light receiving unit and the signal generated by the second light receiving unit by the multiplication factor determined by the multiplication factor determination unit.
[0014] Effects of the Invention
[0015] According to the smoke detection device of the present invention, even if the smoke detection device has been degraded over time, it is still possible to accurately determine the type of smoke. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 FIG. 1 is a diagram schematically showing the structure of a smoke detection device according to an embodiment.
[0017] Figure 2 This is a graph showing the change over time in the amplitude value of a signal generated by a first light receiving unit and amplified by a signal amplifier of a smoke detection device according to an embodiment.
[0018] Figure 3 The graph shows the temporal variation of the ratio of the amplitude value of the signal generated by the second light receiving unit amplified by the signal amplifier to the amplitude value of the signal generated by the first light receiving unit amplified by the signal amplifier of the smoke detection device according to one embodiment. DETAILED DESCRIPTION
[0019] [Implementation Method]
[0020] Hereinafter, a smoke detection device 1 according to an embodiment of the present invention will be described. The smoke detection device 1 is a double light receiving type smoke detection device. Figure 1 Schematically shows the structure of the smoke detection device 1. Figure 1 In the drawings, components not related to the features of the present invention are omitted from illustration. Figure 1 (A) is a plan view showing the smoke detection device 1 with the cover of the container removed. Figure 1 (B) is viewed along the direction of arrow A Figure 1 A diagram of the cross section shown by the dotted line in (A).
[0021] In the following description, for convenience, Figure 1 The direction in which the paper surface of (A) extends is set to be a horizontal plane.
[0022] The smoke detection device 1 includes a first electronic circuit board 10 , a second electronic circuit board 11 , a third electronic circuit board 12 , a first light emitting unit 13 , a first light receiving unit 14 , a second light receiving unit 15 , a light shielding member 16 , a second light emitting unit 17 , a signal amplifying unit 18 , a signal processing unit 19 , and a container 20 .
[0023] The first electronic circuit board 10 is an electronic circuit board arranged to stand vertically to a horizontal plane. A first light emitting unit 13 is arranged on the first electronic circuit board 10 .
[0024] The second electronic circuit board 11 is an electronic circuit board arranged in a direction along a horizontal plane. The first light receiving unit 14, the light shielding member 16, the second light emitting unit 17, the signal amplifying unit 18, and the signal processing unit 19 are arranged on the second electronic circuit board 11.
[0025] The third electronic circuit board 12 is an electronic circuit board arranged to stand vertically to the horizontal plane. The second light receiving unit 15 is arranged on the third electronic circuit board 12 .
[0026] Furthermore, the signal amplifier 18 and the signal processor 19 may be disposed on an electronic circuit board other than the second electronic circuit board 11 (for example, the first electronic circuit board 10 or the third electronic circuit board 12 ).
[0027] The first light emitting unit 13 is Figure 1 Polarized light is emitted in the direction of the light-emitting axis (hereinafter referred to as "light-emitting axis B") indicated by the middle arrow B. For example, when the polarized light emitted by the first light-emitting portion 13 is linearly polarized light, the direction of the straight line is perpendicular to the horizontal plane, and when the polarized light emitted by the first light-emitting portion 13 is elliptically polarized light, the direction of the major axis of the ellipse is perpendicular to the horizontal plane.
[0028] The first light receiving unit 14 receives light from Figure 1 The first light receiving unit 14 receives light in the direction of the first light receiving axis (hereinafter referred to as "the first light receiving axis C") indicated by the arrow C in (B), and generates a signal indicating the intensity of the received light. Hereinafter, the amplitude value of the signal generated by the first light receiving unit 14 is referred to as the amplitude value A1. The first light receiving axis C is an axis that intersects the light emitting axis B at a predetermined angle in a vertical plane (a plane perpendicular to the horizontal plane) containing the light emitting axis B.
[0029] The second light receiving unit 15 receives the light Figure 1 The second light receiving unit 15 receives light in the direction of the second light receiving axis (hereinafter referred to as "the second light receiving axis D") indicated by the arrow D in (A), and generates a signal indicating the intensity of the received light. Hereinafter, the amplitude value of the signal generated by the second light receiving unit 15 is referred to as the amplitude value A2. The second light receiving axis D is an axis that intersects the light emitting axis B at a predetermined angle in a horizontal plane containing the light emitting axis B.
[0030] In addition, the angle between the light emitting axis B and the first light receiving axis C and the angle between the light emitting axis B and the second light receiving axis D may be the same or different.
[0031] The light shielding member 16 is a cylindrical light shielding member configured to surround the first light receiving portion 14. The bottom surface of the upper side of the light shielding member 16 is open so that light directed toward the first light receiving axis C can reach the first light receiving portion 14. The light shielding member 16 shields light directed toward the first light receiving portion 14 in a direction intersecting the first light receiving axis C. The light shielded by the light shielding member 16 includes light emitted from the first light emitting portion 13 and deviating from the light emitting axis B and directed toward the first light receiving portion 14, and light emitted from the first light emitting portion 13 and reflected in the container 20 and directed toward the first light receiving portion 14. The light shielding member 16 plays a role in reducing the influence of these lights on the determination of the presence or absence of smoke and the determination of the type of smoke.
[0032] The second light emitting unit 17 emits non-polarized light for determining the degree of contamination of at least one of the container 20 and the structure (including the first light emitting unit 13, the first light receiving unit 14, and the second light receiving unit 15) in the container 20. The light emitted by the second light emitting unit 17 is directed toward a wide area including the smoke detection area in the container 20.
[0033] The second light emitting unit 17 is arranged at a position where the light directly from the second light emitting unit 17 to the first light receiving unit 14 is blocked by the light shielding member 16. Therefore, compared with the case where the light emitted by the second light emitting unit 17 can directly reach the first light receiving unit 14, the amplitude value A1 of the signal generated by the first light receiving unit 14 becomes smaller as a whole when the contamination is determined, and the change amount of the amplitude value A1 when contaminated relative to the amplitude value A1 when normal is significantly apparent. Therefore, it becomes easy to determine the degree of contamination.
[0034] The signal amplifier 18 is an amplifier that amplifies the signals generated by the first light receiving unit 14 and the second light receiving unit 15. In this embodiment, the signal amplifier 18 amplifies the signals generated by the first light receiving unit 14 and the second light receiving unit 15 at the same amplification factor G.
[0035] Hereinafter, the amplitude value of the signal generated by the first light receiving unit 14 after being amplified by the signal amplifier 18 is referred to as an amplitude value B1. The amplitude value B1 is a value obtained by multiplying the amplitude value A1 by the amplification factor G. Furthermore, the amplitude value of the signal generated by the second light receiving unit 15 after being amplified by the signal amplifier 18 is referred to as an amplitude value B2. The amplitude value B2 is a value obtained by multiplying the amplitude value A2 by the amplification factor G.
[0036] The signal processing unit 19 is a unit that performs data processing, and includes an A / D converter that converts the analog signal generated by the first light receiving unit 14 and the second light receiving unit 15 and amplified by the signal amplifying unit 18 into a digital signal, a memory (storage unit) that stores data, a processor that processes the data, a clock for timing, etc.
[0037] When the smoke detection device 1 is shipped, the memory stores initial values of the multiplication factor M1 for the first light receiving unit 14 and the multiplication factor M2 for the second light receiving unit 15. During operation of the smoke detection device 1, the multiplication factor M1 and the multiplication factor M2 are updated by a multiplication factor determination unit described later.
[0038] The initial value of the multiplication factor M1 is a value obtained by dividing a predetermined reference value S by an amplitude value B1 of a signal generated by the first light receiving unit 14 after the signal amplifier 18 amplifies the signal in an environment where the container 20 is filled with white smoke (or a substitute for white smoke) of a predetermined concentration and the first light emitting unit 13 emits light. That is, the multiplication factor M1 is set as an initial value in the smoke detection device 1 so that the value obtained by multiplying the amplitude value B1 in the above environment by the multiplication factor M1 becomes the reference value S.
[0039] The initial value of the multiplication factor M2 is a value obtained by dividing the reference value S by the amplitude value B2 of the signal generated by the second light receiving unit 15 after the signal amplifier 18 amplifies the signal in an environment where the container 20 is filled with white smoke and the first light emitting unit 13 emits light. That is, the multiplication factor M2 is set as the initial value in the smoke detection device 1 so that the value obtained by multiplying the amplitude value B2 in the above environment by the multiplication factor M2 becomes the reference value S.
[0040] Hereinafter, the amplitude value obtained by multiplying the amplitude value B1 of the signal generated by the first light receiving unit 14 after the signal amplifier 18 amplifies the signal by the multiplication factor M1 is referred to as the amplitude value C1 of the first light receiving unit 14. Furthermore, the value obtained by multiplying the amplitude value B2 of the signal generated by the second light receiving unit 15 after the signal amplifier 18 amplifies the signal by the multiplication factor M2 is referred to as the amplitude value C2 of the second light receiving unit 15.
[0041] Here, the reference value S used in calculating the initial value of the multiplication factor M1 and the reference value S used in calculating the initial value of the multiplication factor M2 are the same value. Therefore, the ratio of the amplitude value B2 to the amplitude value B1 (or the amplitude value C2 to the amplitude value C1) in the environment where the container 20 is filled with white smoke and the first light emitting unit 13 emits light is 1. In addition, the reference value S used in calculating the initial value of the multiplication factor M1 and the reference value S used in calculating the initial value of the multiplication factor M2 may be different values.
[0042] The signal processing unit 19 functions as a device including a light emission control unit, a smoke determination unit, a contamination determination unit, a multiplication factor determination unit, and an abnormality detection unit by performing data processing by a processor according to a program stored in a memory.
[0043] The light emission control unit instructs the first light emitting unit 13 and the second light emitting unit 17 to start and stop emitting light. In this embodiment, as an example, the smoke detection device 1 operates in the smoke determination mode from 0:00 to 23:59 every day, and operates in the contamination determination mode from 23:59 to 24:00 (0:00 the next day).
[0044] The smoke determination mode is an operation mode for detecting smoke and determining the type of the detected smoke. When the smoke determination mode starts, the light emission control unit instructs the first light emission unit 13 to start emitting light and instructs the second light emission unit 17 to stop emitting light.
[0045] The contamination determination mode is a mode for determining the degree of contamination of at least one of the container 20 and the structure in the container 20. When the contamination determination mode starts, the light emission control unit instructs the first light emitting unit 13 to stop emitting light and instructs the second light emitting unit 17 to start emitting light.
[0046] In addition, the lengths of the smoke determination pattern and the contamination determination pattern are not limited to the above-mentioned lengths.
[0047] In the smoke determination mode, the smoke determination unit detects smoke in the air based on the signal generated by the first light receiving unit 14 .
[0048] In order for the smoke determination unit to detect smoke, a threshold U1 for smoke detection is stored in the memory. In the smoke determination mode, the smoke determination unit determines that smoke has been generated in the space around the smoke detection device 1 when the comparison result between the amplitude value C1 obtained by multiplying the amplitude value B1 of the signal generated by the first light receiving unit 14 by the multiplication factor M1 and the threshold U1 satisfies a predetermined condition E1. The condition E1 is, for example, a condition that the determination result that the amplitude value C1 exceeds the threshold U1 in the comparison between the amplitude value C1 and the threshold U1 repeatedly performed at a predetermined time interval appears a predetermined number of times continuously, but is not limited thereto.
[0049] When the smoke determination unit detects smoke in the air of the space surrounding the smoke detection device 1 through the above-mentioned determination, it determines the type of smoke in the air of the space surrounding the smoke detection device 1 based on the signal generated by the first light receiving unit 14 during the period when the first light emitting unit 13 emits light and the signal generated by the second light receiving unit 15 during the period when the first light emitting unit 13 emits light.
[0050] In order for the smoke determination unit to determine the type of smoke, for example, a threshold value U2 for distinguishing between white smoke and gray smoke and a threshold value U3 for distinguishing between gray smoke and black smoke are stored in the memory.
[0051] In addition, white smoke, gray smoke, and black smoke are examples of the types of smoke that the smoke determination unit can distinguish, and other types of smoke can also be distinguished. In addition, the number of thresholds used in the smoke determination unit to determine the type of smoke can be changed according to the number of types of smoke that the smoke determination unit can distinguish and the determination method thereof.
[0052] When smoke is detected in the smoke determination mode, the smoke determination unit calculates a ratio R of an amplitude value C2 obtained by multiplying an amplitude value B2 of a signal generated by the second light receiving unit 15 amplified by the signal amplifying unit 18 by a multiplication factor M2 to an amplitude value C1 obtained by multiplying an amplitude value B1 of a signal generated by the first light receiving unit 14 amplified by the signal amplifying unit 18 by a multiplication factor M1. Then, if the ratio R is less than a threshold value U2, the smoke determination unit determines the type of smoke to be white smoke, if the ratio R is greater than the threshold value U2 and less than the threshold value U3, the smoke determination unit determines the type of smoke to be gray smoke, and if the ratio R is greater than the threshold value U3, the smoke determination unit determines the type of smoke to be black smoke.
[0053] When the smoke determination unit detects smoke, the smoke detection device 1 performs the following predetermined processing, for example: Figure 1 The display (LCD display or 7-segment LED, etc.) will display a warning message such as "white smoke is generated"; Figure 1The warning message is displayed on the Figure 1 The communication unit (omitted in the figure) lights up; Figure 1 A notification indicating that smoke has been detected and the type of smoke is sent to a higher-level system (not shown).
[0054] In the contamination determination mode, the contamination determination unit determines the degree of contamination of at least one of the container 20 and the structure in the container 20 based on at least one of the signal generated by the first light receiving unit 14 and the signal generated by the second light receiving unit 15 .
[0055] In order for the contamination determination unit to determine the degree of contamination, a threshold value U4 and a threshold value U5 for contamination determination are stored in the memory. In the contamination determination mode, the contamination determination unit determines that the degree of contamination of the container 20 or the structure in the container 20 exceeds the allowable range, for example, when the amplitude value C1 obtained by multiplying the amplitude value B1 of the signal generated by the first light receiving unit 14 by the multiplication factor M1 after the signal amplifier 18 amplifies the signal is lower than the threshold value U4, or when the amplitude value C2 obtained by multiplying the amplitude value B2 of the signal generated by the second light receiving unit 15 by the multiplication factor M2 after the signal amplifier 18 amplifies the signal is lower than the threshold value U5.
[0056] When the contamination determination unit determines that the degree of contamination exceeds the allowable range, the smoke detection device 1 emits a signal from a speaker (for example, Figure 1 (not shown in the figure) sends a warning message such as "cleaning is required", and from the communication unit (in Figure 1 (not shown in the figure) sends a notification to the upper system urging the smoke detection device 1 to be cleaned.
[0057] The multiplication factor determination unit plays the following role: updating the multiplication factors M1 and M2 during the operation of the smoke detection device 1 to reduce the impact of the aging degradation and contamination of the first light emitting unit 13, the first light receiving unit 14, and the second light receiving unit 15 on the determination result of the smoke determination unit.
[0058] Therefore, the multiplication factor determination unit determines the multiplication factor to be multiplied with at least one of the signal generated by the first light receiving unit 14 and the signal generated by the second light receiving unit 15 in such a manner that the ratio of the amplitude value of the signal generated by the second light receiving unit 15 to the amplitude value of the signal generated by the first light receiving unit 14 becomes a prescribed value in the smoke determination mode during a period when the smoke determination unit does not detect smoke in the air.
[0059] In the present embodiment, the multiplication factor determination unit determines update values of both the multiplication factor M1 and the multiplication factor M2. A specific example is shown below.
[0060] In order for the multiplication factor determination unit to determine update values of the multiplication factors M1 and M2, the amplitude value γ1 and the amplitude value γ2 are stored in the memory when the smoke detection device 1 is shipped.
[0061] The amplitude value γ1 is a value obtained by multiplying the amplitude value B1 of the signal generated by the first light receiving unit 14 in the smoke determination mode in a non-smoking environment by the initial value of the factor M1 when the smoke detection device 1 is shipped.
[0062] The amplitude value γ2 is a value obtained by multiplying the amplitude value B2 of the signal generated by the second light receiving unit 15 in the smoke determination mode in a non-smoking environment by the initial value of the factor M2 when the smoke detection device 1 is shipped.
[0063] Furthermore, in order for the multiplier determination unit to determine the updated values of the multipliers M1 and M2, in the memory, for example, the amplitude value B1 and the amplitude value B2 continuously measured when the smoke detection device 1 is used are stored in sequence as log data for a period of a recently specified length of time (hereinafter set to 10 minutes).
[0064] For example, every time a predetermined length of time (eg, 30 days) elapses, the multiplication factor determination unit first identifies a recent period during which no smoke was detected.
[0065] Figure 2 : is a graph showing the temporal change of the amplitude value B1 within a period of a predetermined time length in the recent past, which is shown by the log data stored in the memory. Figure 2 In the example of FIG. 2 , period T4 is a period of the contamination determination mode, and the other periods are periods of the smoke determination mode.
[0066] exist Figure 2 In the case of the example, the multiplication factor determination unit determines that the value obtained by multiplying the amplitude value B1 in the period T2 shown in the log data read from the memory by the multiplication factor M1 at that time point continues to exceed the threshold value U1. As a result, the multiplication factor determination unit determines the period T2 as the period in which smoke is detected, and determines the other periods, namely the periods T1, T3, T4, and T5, as the periods in which smoke is not detected.
[0067] Next, the multiplication factor determination unit calculates, for example, an average value D1 of the amplitude values B1 during the periods T1, T3, T4, and T5, excluding the period T4 in the contamination determination mode, as a representative value of the amplitude values B1 during the periods T1, T3, T4, and T5 during which smoke is not detected. Alternatively, a median value, a mode value, or the like may be used as a representative value instead of the average value.
[0068] Next, the multiplication factor determination unit divides the amplitude value γ1 by the average value D1 to calculate an updated multiplication factor M1. The updated multiplication factor M1 calculated in this way is a multiplication factor in which the amplitude value C1 calculated in the smoke detection device 1 in the smoke determination mode in the non-smoking environment at the current time point is adjusted to be consistent with the amplitude value γ1 calculated in the smoke detection device 1 in the smoke determination mode in the non-smoking environment at the time of shipment. The multiplication factor determination unit overwrites the multiplication factor M1 stored in the memory with the updated multiplication factor M1 calculated in this way.
[0069] Next, the multiplication factor determination unit calculates, for example, an average value D2 of the amplitude values B2 in the periods T1 , T3 , and T5 as a representative value of the amplitude values B2 in these periods.
[0070] Next, the multiplication factor determination unit divides the amplitude value γ2 by the average value D2 to calculate an updated multiplication factor M2. The updated multiplication factor M2 calculated in this way is a multiplication factor in which the amplitude value C2 calculated in the smoke detection device 1 in the smoke determination mode in the non-smoking environment at the current time point is adjusted to be consistent with the amplitude value γ2 calculated in the smoke detection device 1 in the smoke determination mode in the non-smoking environment at the time of shipment. The multiplication factor determination unit overwrites the multiplication factor M2 stored in the memory with the updated multiplication factor M2 calculated in this way.
[0071] The ratio of the amplitude value C1 to the amplitude value C2 calculated using the updated multiplication factor M1 and the multiplication factor M2 determined by the multiplication factor determination unit as described above is consistent with the ratio of the amplitude value γ1 to the amplitude value γ2. That is, the multiplication factor determination unit determines the updated multiplication factor M1 and the multiplication factor M2 so that the ratio of the amplitude value C2 to the amplitude value C1 becomes the ratio of the amplitude value γ2 given as the initial value to the amplitude value γ1.
[0072] By updating the multiplication factors M1 and M2 by the multiplication factor determination unit as described above, the influence of the aging degradation and contamination of the smoke detection device 1 on the determination result of the smoke determination unit is reduced.
[0073] The abnormality detector detects abnormality of the smoke detection device 1 based on the ratio of the amplitude value of the signal generated by the second light receiving unit 15 to the amplitude value of the signal generated by the first light receiving unit 14 in the smoke determination mode while the smoke determination unit does not detect smoke in the air.
[0074] In order to detect abnormality of the smoke detection device 1, the abnormality detection unit reads log data from the memory every time a predetermined time length (e.g., 5 minutes) elapses, and calculates the ratio P of the amplitude value B2 measured at the same timing shown in the log data to the amplitude value B1.
[0075] Figure 3 2 is an example of a graph showing a temporal change in the ratio P calculated by the abnormality detection unit for a predetermined period in the past. Figure 3In the example of FIG. 1 , the period T4 is the period of the contamination determination mode, and the period T2 is the period during which smoke is detected. In addition, the abnormality detection unit determines the period during which smoke is detected by the same method as the multiplication factor determination unit.
[0076] The abnormality detection unit detects that the ratio P changes discontinuously at time t1 among the periods T1, T3, and T5 during which no smoke is detected in the smoke determination mode. The abnormality detection unit determines the time when the ratio P changes discontinuously based on, for example, a determination result of whether the rate of change of the moving average of the ratio P exceeds a predetermined threshold value, but may also determine the time when the ratio P changes discontinuously by other known methods.
[0077] If the ratio P changes discontinuously, there is a high possibility that a component of the smoke detection device 1 has failed or large amounts of dust have adhered to it. Therefore, in this case, the abnormality detection unit determines that some abnormality has occurred in the smoke detection device 1 at time t1.
[0078] When the abnormality detection unit detects an abnormality of the device, the smoke detection device 1 emits a signal from a speaker (for example, Figure 1 (not shown in the figure) issues a warning message such as "abnormality has occurred", and the communication unit (in Figure 1 A notification indicating that an abnormality has occurred is sent to a higher-level system.
[0079] As described above, the abnormality detection unit detects the abnormality of the smoke detection device 1 based on the ratio P of the amplitude value B2 to the amplitude value B1, and as a result, it is possible to detect the occurrence of an abnormality that is difficult to detect when, for example, the abnormality of the smoke detection device 1 is detected only based on the amplitude value B1 or when the abnormality of the smoke detection device 1 is detected only based on the amplitude value B2. For example, when dust is generated around the smoke detection device 1 and fine dust intrudes into the container 20, the amplitude value B1 and the amplitude value B2 change in a linked manner. Therefore, compared with the amplitude value B1 or the amplitude value B2, the ratio P is not easily affected by these interferences. Therefore, by performing abnormality detection based on the ratio P, it is possible to easily detect abnormalities that do not depend on these interferences.
[0080] The above is the description of the processing performed by the signal processing unit 19.
[0081] Container 20 (refer to Figure 1 ) is a component forming a dark space for detecting smoke, and contains the first light emitting unit 13, the first light receiving unit 14, the second light receiving unit 15, etc. The container 20 is provided with: an inlet, which is a passage for air to flow into the interior from the space of the monitored object; and an outlet, which is a passage for the air flowing into the interior to flow out to the outside.
[0082] In addition, the smoke detection device 1 Figure 1In addition to the components shown, for example, a fan for forcibly generating an air flow from the outside toward the inside of the container 20, or a filter for removing dust larger than smoke particles from the air toward the inside of the container 20, etc. may be provided.
[0083] According to the above-described smoke detection device 1, even if deterioration due to age or the like occurs, the type of smoke can be accurately determined.
[0084] [Modifications]
[0085] The above embodiment is a specific example of the present invention, and various modifications can be made within the scope of the technical concept of the present invention. The following are their modifications. In addition, two or more modifications shown below can also be appropriately combined.
[0086] (Variant 1)
[0087] In the above-mentioned embodiment, the multiplication factor determination unit determines the updated multiplication factors M1 and M2 based on the signals generated by the first light receiving unit 14 and the second light receiving unit 15 in the smoke determination mode, that is, in the state where the first light emitting unit 13 emits light, in a smoke-free environment. In this case, the signals generated by the first light receiving unit 14 and the second light receiving unit 15 are signals generated by reacting with the light reflected by the inner wall surface of the container 20 or the structure in the container 20, that is, the stray light in the light emitted by the first light emitting unit 13. Therefore, the amplitude values of the signals generated by the first light receiving unit 14 and the second light receiving unit 15 are sometimes too small.
[0088] Therefore, the following structure may be adopted: the multiplication factor determination unit determines the updated multiplication factors M1 and M2 based on the signals generated by the first light receiving unit 14 and the second light receiving unit 15 in the contamination determination mode rather than the smoke determination mode, that is, when the second light emitting unit 17 is emitting light.
[0089] Hereinafter, the differences between the smoke detection device 1 of this modification and the smoke detection device 1 of the above-described embodiment will be described, and description of the common points will be omitted.
[0090] First, in this modification, at the time of factory shipment, the amplitude value γ1 and the amplitude value γ2 different from those in the above-described embodiment are stored in the memory.
[0091] In the above-mentioned embodiment, the amplitude value γ1 and the amplitude value γ2 are values based on the signal generated by the first light receiving unit 14 or the second light receiving unit 15 in the smoke determination mode. In contrast, in this modified example, the amplitude value γ1 and the amplitude value γ2 are values based on the signal generated by the first light receiving unit 14 or the second light receiving unit 15 in the contamination determination mode.
[0092] That is, in this modification, the amplitude value γ1 is a value obtained by multiplying the amplitude value B1 of the signal generated by the first light receiving unit 14 in the contamination determination mode in a smoke-free environment by the initial value of the multiplication factor M1 when the smoke detection device 1 is shipped.
[0093] In this modified example, the amplitude value γ2 is a value obtained by multiplying the amplitude value B2 of the signal generated by the second light receiving unit 15 in the contamination determination mode in a smoke-free environment by the initial value of the multiplication factor M2 when the smoke detection device 1 is shipped.
[0094] Next, in this modified example, as log data, for example, the amplitude value B1 and the amplitude value B2 measured in the stain determination mode for a predetermined number of times in the recent past are stored. Hereinafter, as an example, it is assumed that the amplitude value B1 and the amplitude value B2 in the stain determination mode for the five most recent times are stored in the log data, and the period of these five stain determination modes is set as the period T1 to T5.
[0095] In this modification, for example, every time a predetermined time length (e.g., 30 days) elapses, the multiplication factor determination unit calculates the average values of the amplitude value B1 and the amplitude value B2 for each of the periods T1 to T5 indicated in the log data. Hereinafter, the average values of the amplitude value B1 for each of the periods T1 to T5 are referred to as average values F1(T1) to F1(T5), and the average values of the amplitude value B2 for each of the periods T1 to T5 are referred to as average values F2(T1) to F2(T5).
[0096] The multiplication factor determination unit calculates average values of amplitude value B1 and amplitude value B2 over the period T1 to T5. Hereinafter, the average value of amplitude value B1 over the period T1 to T5 is referred to as average value F1, and the average value of amplitude value B2 over the period T1 to T5 is referred to as average value F2.
[0097] If there is an average value among the average values F1(T1) to F1(T5) whose difference from the average value F1 is greater than a predetermined threshold, the multiplication factor determination unit excludes the period corresponding to the average value as a period during which smoke is detected. Furthermore, if there is an average value among the average values F2(T1) to F1(T5) whose difference from the average value F2 is greater than a predetermined threshold, the multiplication factor determination unit determines the period corresponding to the average value as a period during which smoke is detected.
[0098] Below, as an example, assuming that the difference between the average value F1(T2) and the average value F1 is greater than the specified threshold, and the difference between the average value F2(T2) and the average value F2 is greater than the specified threshold, period T2 is determined as a period during which smoke is detected, and periods T1, T3, T4, and T5 are determined as periods during which smoke is not detected.
[0099] Next, the multiplication factor determination unit calculates an average value D1 of the amplitude values B1 during the periods T1, T3, T4, and T5 during which smoke is not detected. Also, the multiplication factor determination unit calculates an average value D2 of the amplitude values B2 during the periods T1, T3, T4, and T5 during which smoke is not detected.
[0100] Next, the multiplication factor determination unit divides the amplitude value γ1 by the average value D1 to calculate an updated multiplication factor M1. The updated multiplication factor M1 calculated in this way is a multiplication factor in which the amplitude value C1 calculated in the contamination determination mode in the smoke detection device 1 at the current time point is adjusted to be consistent with the amplitude value γ1 calculated in the contamination determination mode in the smoke detection device 1 at the time of shipment. The multiplication factor determination unit overwrites the multiplication factor M1 stored in the memory with the updated multiplication factor M1 calculated in this way.
[0101] Next, the multiplication factor determination unit divides the amplitude value γ2 by the average value D2 to calculate an updated multiplication factor M2. The updated multiplication factor M2 calculated in this way is a multiplication factor in which the amplitude value C2 calculated in the contamination determination mode in the smoke detection device 1 at the current time point is adjusted to be consistent with the amplitude value γ2 calculated in the contamination determination mode in the smoke detection device 1 at the time of shipment. The multiplication factor determination unit overwrites the multiplication factor M2 stored in the memory with the updated multiplication factor M2 calculated in this way.
[0102] The ratio of the amplitude value C1 to the amplitude value C2 calculated using the updated multiplication factor M1 and the multiplication factor M2 determined by the multiplication factor determination unit as described above is consistent with the ratio of the amplitude value γ1 to the amplitude value γ2. That is, the multiplication factor determination unit determines the updated multiplication factor M1 and the multiplication factor M2 so that the ratio of the amplitude value C2 to the amplitude value C1 becomes the ratio of the amplitude value γ2 to the amplitude value γ1 given as the initial value.
[0103] According to this variation, even in a case where the amplitude value of the signal generated by the reaction of the first light receiving unit 14 and the second light receiving unit 15 with the stray light of the light emitted by the first light emitting unit 13 is too small, the multipliers M1 and M2 can be updated based on a sufficiently large amplitude value of the signal generated by the reaction of the first light receiving unit 14 and the second light receiving unit 15 with the light emitted by the second light emitting unit 17, thereby reducing the influence of the aging degradation and contamination of the smoke detection device 1 on the determination result of the smoke determination unit.
[0104] (Variant 2)
[0105] In the above embodiment, the multiplication factor determination unit calculates the updated multiplication factor M1 and the multiplication factor M2 separately. That is, the multiplication factor determination unit calculates the updated multiplication factor M1 based on the amplitude value γ1, and calculates the updated multiplication factor M2 based on the amplitude value γ2. Alternatively, the multiplication factor determination unit may determine the updated multiplication factor M2 based on the updated multiplication factor M1.
[0106] In this modification, the amplitude value γ1 and the ratio Q are stored in the memory at the time of shipment. The amplitude value γ1 is the same as the amplitude value γ1 of the above embodiment. As in the above embodiment, the multiplication factor determination unit determines the updated multiplication factor M1 using the amplitude value γ1.
[0107] The ratio Q is the ratio of the amplitude value γ2 to the amplitude value γ1 in the above-described embodiment.
[0108] The multiplication factor determination unit calculates the updated multiplication factor M2 in such a manner that the ratio of the amplitude value C2 calculated using the updated multiplication factor M2 to the amplitude value C1 calculated using the updated multiplication factor M1 becomes the ratio Q. That is, the multiplication factor determination unit calculates the updated multiplication factor M2 by dividing the average value of the amplitude value B1 during the period when smoke is not detected in the smoke determination mode shown in the log data by the updated multiplication factor M1 and the ratio Q, by the average value of the amplitude value B2 during the period when smoke is not detected in the smoke determination mode shown in the log data.
[0109] In the above example, the method for determining the updated multiplier M1 in this variant is the same as the method for determining the updated multiplier M1 in the above embodiment. As a result, the updated multiplier M2 determined in this variant is the same as the updated multiplier M2 determined in the above embodiment.
[0110] However, in this variant, the updated multiplier M1 may be determined by a method different from the above-described embodiment. In this variant, no matter what method is used as the method for determining the updated multiplier M1, the ratio of the amplitude value C2 calculated using the updated multiplier M1 and the multiplier M2 to the amplitude value C1 is a constant ratio Q.
[0111] Modification 2 may be combined with Modification 1. In this case, the ratio Q of amplitude value γ1 and amplitude value γ2 of Modification 1 to amplitude value γ1, which is the same as amplitude value γ1 of Modification 1, may be stored in the memory at the time of shipment.
[0112] (Variant 3)
[0113] In the above embodiment, the signal amplifier 18 of the smoke detection device 1 is not essential. When the smoke detection device 1 does not have the signal amplifier 18, the amplitude value A1 is used instead of the amplitude value B1 of the above embodiment, and the amplitude value A2 is used instead of the amplitude value B2 of the above embodiment.
[0114] (Variant 4)
[0115] In the above embodiment, the signal amplifier 18 amplifies the signal generated by the first light receiving unit 14 and the signal generated by the second light receiving unit 15 at the same amplification factor. However, the signal amplifier 18 may amplify these signals at different amplification factors.
[0116] Description of symbols
[0117] 1: smoke detection device; 10: first electronic circuit substrate; 11: second electronic circuit substrate; 12: third electronic circuit substrate; 13: first light-emitting unit; 14: first light-receiving unit; 15: second light-receiving unit; 16: light-shielding component; 17: second light-emitting unit; 18: signal amplifying unit; 19: signal processing unit; 20: container.
Claims
1. A smoke detection device, comprising: a light emitting portion that emits polarized light; a first light receiving portion having a first light receiving axis intersecting with the light emitting axis of the light emitting portion; a second light receiving portion having a second light receiving axis intersecting with the light emitting axis of the light emitting portion and in a different direction from the first light receiving axis; a smoke determination unit that detects smoke in the air based on the signal generated by the first light receiving unit during the period when the light emitting unit emits light, and, when smoke is detected, determines the type of smoke in the air based on the signal generated by the first light receiving unit during the period when the light emitting unit emits light and the signal generated by the second light receiving unit during the period when the light emitting unit emits light; as well as a multiplication factor determination unit that determines a multiplication factor to be multiplied with at least one of the signal generated by the first light receiving unit and the signal generated by the second light receiving unit in such a manner that a ratio of an amplitude value of a signal generated by the second light receiving unit during a period when the light emitting unit emits light relative to an amplitude value of a signal generated by the first light receiving unit during a period when the light emitting unit emits light becomes a predetermined value during a period when the smoke determination unit does not detect smoke in the air, The smoke determination unit determines the type of smoke in the air based on a value obtained by multiplying an amplitude value of at least one of the signal generated by the first light receiving unit and the signal generated by the second light receiving unit by the multiplication factor determined by the multiplication factor determination unit.
2. The smoke detection device according to claim 1, wherein: The smoke detection device includes a storage unit that stores an amplitude value of a signal generated by the first light receiving unit. The multiplication factor determination unit reads from the storage unit the amplitude value of the signal generated by the first light receiving unit during the past period when the smoke determination unit did not detect smoke in the air and during the period when the light emitting unit emitted light, and determines the multiplication factor for the first light receiving unit to be multiplied by the signal of the first light receiving unit in such a manner that the amplitude value becomes a predetermined value. The smoke determination unit detects smoke in the air based on a value obtained by multiplying an amplitude value of a signal generated by the first light receiving unit while the light emitting unit is emitting light by a multiplication factor for the first light receiving unit.
3. The smoke detection device according to claim 2, wherein: The polarized light emitted by the light emitting portion is linearly polarized light or elliptically polarized light. The plane including the first light receiving axis and the light emitting axis of the light emitting portion is parallel to the plane including the direction of the straight line of the linearly polarized light emitted by the light emitting portion or the plane including the major axis of the ellipse of the elliptically polarized light emitted by the light emitting portion, The plane containing the second light receiving axis and the light emitting axis of the light emitting portion is perpendicular to the plane containing the direction of the straight line of the linearly polarized light emitted by the light emitting portion or the plane containing the major axis of the ellipse of the elliptically polarized light emitted by the light emitting portion, The multiplication factor determination unit determines the multiplication factor for the second light receiving unit based on the multiplication factor for the first light receiving unit.
4. The smoke detection device according to claim 1, wherein: The smoke detection device has an abnormality detection unit, which detects abnormality of the device based on the ratio of the amplitude value of the signal generated by the second light receiving unit during the period when the light emitting unit emits light to the amplitude value of the signal generated by the first light receiving unit during the period when the light emitting unit emits light during the period when the smoke determination unit does not detect smoke in the air.
5. A smoke detection device, comprising: A first light emitting unit that emits polarized light; a first light receiving portion having a first light receiving axis intersecting with the light emitting axis of the first light emitting portion; a second light receiving portion having a second light receiving axis intersecting with the light emitting axis of the first light emitting portion and in a different direction from the first light receiving axis; a smoke determination unit that detects smoke in the air based on a signal generated by the first light receiving unit during the period when the first light emitting unit emits light, and, when smoke is detected, determines the type of smoke in the air based on a signal generated by the first light receiving unit during the period when the first light emitting unit emits light and a signal generated by the second light receiving unit during the period when the first light emitting unit emits light; a second light emitting unit that emits non-polarized light; and a multiplication factor determination unit that determines a multiplication factor to be multiplied with at least one of the signal of the first light receiving unit and the signal of the second light receiving unit in such a manner that a ratio of an amplitude value of a signal generated by the second light receiving unit during a period when the second light emitting unit emits light relative to an amplitude value of a signal generated by the first light receiving unit during a period when the second light emitting unit emits light becomes a predetermined value, The smoke determination unit determines the type of smoke in the air based on a value obtained by multiplying an amplitude value of at least one of the signal generated by the first light receiving unit and the signal generated by the second light receiving unit by the multiplication factor determined by the multiplication factor determination unit.
6. The smoke detection device according to claim 5, wherein: The smoke detection device has a contamination determination unit, which determines the degree of contamination of at least one of a container forming a space for detecting smoke and a structure within the container based on at least one of a signal generated by the first light receiving unit during a period when the second light emitting unit emits light and a signal generated by the second light receiving unit during a period when the second light emitting unit emits light.
7. The smoke detection device according to claim 5, wherein: The smoke detection device includes a storage unit that stores an amplitude value of a signal generated by the first light receiving unit. The multiplication factor determination unit reads from the storage unit the amplitude value of the signal generated by the first light receiving unit during the past period when the smoke determination unit did not detect smoke in the air and during the period when the second light emitting unit was emitting light, and determines the multiplication factor for the first light receiving unit to be multiplied by the signal of the first light receiving unit in such a manner that the amplitude value becomes a predetermined value. The smoke determination unit detects smoke in the air based on a value obtained by multiplying an amplitude value of a signal generated by the first light receiving unit while the first light emitting unit is emitting light by a multiplication factor for the first light receiving unit.
8. The smoke detection device according to claim 5, wherein: The polarized light emitted by the first light emitting portion is linearly polarized light or elliptically polarized light. The plane including the first light receiving axis and the light emitting axis of the first light emitting portion is parallel to the plane including the direction of the straight line of the linearly polarized light emitted by the first light emitting portion or the plane including the major axis of the ellipse of the elliptically polarized light emitted by the first light emitting portion, The plane containing the second light receiving axis and the light emitting axis of the first light emitting portion is perpendicular to the plane containing the direction of the straight line of the linearly polarized light emitted by the first light emitting portion or the plane containing the major axis of the ellipse of the elliptically polarized light emitted by the first light emitting portion, The multiplication factor determination unit determines the multiplication factor for the second light receiving unit based on the multiplication factor for the first light receiving unit.
9. The smoke detection device according to claim 5, wherein: The smoke detection device has an abnormality detection unit, which detects abnormality of the device based on the ratio of the amplitude value of the signal generated by the second light receiving unit during the period when the first light emitting unit is emitting light to the amplitude value of the signal generated by the first light receiving unit during the period when the first light emitting unit is emitting light during the period when the smoke determination unit does not detect smoke in the air.
10. The smoke detection device according to claim 1 or 5, wherein: The smoke detection device includes a signal amplifying unit that amplifies the signal generated by the first light receiving unit and the signal generated by the second light receiving unit. The multiplication factor determination unit and the smoke determination unit use the amplitude value of the signal generated by the first light receiving unit after amplifying the signal generated by the first light receiving unit by the signal amplifier to replace the amplitude value of the signal generated by the first light receiving unit, and use the amplitude value of the signal generated by the second light receiving unit after amplifying the signal generated by the second light receiving unit by the signal amplifier to replace the amplitude value of the signal generated by the second light receiving unit.