Smoke detector

Abstract

The challenge lies in reducing the generation of useless records that essentially represent the same value by smoke sensors that can produce recorded data representing the flow meter's measurement value. The flow meter (115) measures the airflow entering the sensing area of ​​the smoke sensor from the external space. The smoke sensor includes a control unit (118), which has a flow signal acquisition means (183) that acquires a flow signal representing the measurement value of the flow meter (115), and a memory means (1180) that temporarily stores this flow signal in a flow temporary memory table. A recording generation means (1184) generates recorded data representing the flow measurement value at a given time point when it is determined that the rate of change of the flow measurement value stored in the flow temporary memory table has reached a set airflow change step value, and the memory means (1180) adds this recorded data to the flow recording table. A limit value changing means (1187) changes the set airflow change step value according to a predetermined operation performed by the user on the button (116).

Description

Technical Field

[0001] This invention relates to a technology for sensing smoke. Prior Technology

[0002] There is a smoke detector that detects the generation of smoke in the external space by sensing particles contained in the air flowing into the sensing area from the external space.

[0003] For example, a smoke sensor known as a photoelectric smoke sensor emits light from a light-emitting element to a sensing area, and uses a light-receiving element to receive the scattered light reflected by particles in the air within the sensing area. Then, based on the intensity of the light received by the light-receiving element and measured, it senses the particles contained in the air flowing into the sensing area from the outside space, thereby sensing the occurrence of smoke in the outside space.

[0004] Patent document 1 is one example of a patent document that discloses the technology of photoelectric smoke detectors. The photoelectric smoke detector described in Patent Document 1 has the following invention: when smoke particles that are not hot air or the like flow into the smoke detection space (sensing area) and when smoke flows into the smoke detection space, the focus is on the method of the change of the output signal of the light-receiving element over time, and the output signal output from the light-receiving element is delayed by only a predetermined delay time, thereby avoiding the failure to detect smoke falsely when hot air or the like occurs. [Previous Technical Documents] [Patent Literature]

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-61423 Summary of the Invention

[0006] [The problem that the invention aims to solve]

[0007] Like photoelectric smoke sensors, smoke sensors (hereinafter referred to as "smoke sensors") detect the occurrence of smoke in the external space by sensing particles contained in the air flowing into the sensing area from the external space. To prevent dust particles larger than smoke particles from entering the sensing area and adhering to light-emitting elements and light-receiving elements as dirt, a filter with a mesh size of coarseness is installed in the airflow path from the external space to the sensing area, allowing smoke to pass through but preventing dust from passing through. When this filter becomes clogged or damaged for some reason, the photoelectric smoke sensor cannot accurately detect smoke occurring in the external space. Furthermore, in some cases, dust and other particles may adhere to the inner wall of pipes or other structures forming the airflow path from the external space to the sensing area, obstructing airflow. In this case, the photoelectric smoke sensor also cannot accurately detect smoke occurring in the external space.

[0008] To detect anomalies like those described above, the following mechanism can be considered: Install a flow meter to measure the airflow from external space into the sensing area, and monitor whether the measured airflow is within an appropriate range. In this mechanism, the data representing the flow meter's measurement results is stored as log data, and the changes in airflow over time are analyzed. This allows for the estimation of the cause when the airflow has fallen outside the appropriate range, or the estimation of the period during which the airflow fell outside the appropriate range.

[0009] For example, when the flow meter's measurement results are stored as data at predetermined intervals, essentially identical data representing the same value is wasted during periods when airflow remains almost constant. For instance, when data is stored in a smoke sensor, useless data is stored in the limited memory area, which is undesirable. Furthermore, when data is sent from the smoke sensor to an upper system and stored there, data traffic increases due to useless data, which is also undesirable. Moreover, when maintenance personnel verify the data, if there are many essentially identical data points, time is wasted on verification, which is also undesirable.

[0010] Therefore, new data is generated each time the rate of change of the flow measured by the flow meter (the value obtained by dividing the absolute value of the change in flow from the last time the data was generated by the flow rate at the last time the data was generated) reaches a predetermined threshold, thereby reducing the generation of useless data. Hereinafter, the threshold value of the rate of change of flow used as the condition for generating data is called the "airflow change step value".

[0011] However, the rate of change of airflow into the sensing area of ​​a smoke detector from external space largely varies depending on whether the flow rate is low or high. For example, the lower the flow rate, the greater the rate of change will be even for small changes in flow. Consequently, in the case of low flow, the rate of change will frequently reach the airflow change step value, resulting in missing data and useless records.

[0012] In view of this situation, the present invention provides a means to reduce the loss of useless recorded data that substantially represents the same value in a smoke sensor that can generate recorded data representing the measurement value of a flow meter. [Methods for solving problems]

[0013] To address the aforementioned issues, this invention proposes a smoke detector that senses the generation of smoke in the external space by sensing particles contained in the air flowing into the sensing area from the external space. The smoke detector comprises: a flow rate measurement means for measuring air flow rate; a recording generation means for generating recorded data indicating when the rate of change of the measured value of the flow rate measurement means has reached a threshold value; and a threshold value modification means for modifying the threshold value. [Invention Effects]

[0014] According to the present invention, the airflow change step value is changed to an appropriate value according to the airflow rate flowing into the sensing area from the external space, thereby generating recorded data representing the measurement value of the flow rate measurement means at an appropriate frequency. As a result, the lack of recorded data that substantially represents the same value can be reduced. Simple Explanation of the Diagram

[0015] [Figure 1] is a diagram showing the configuration of a smoke detection system in one embodiment. [Figure 2] is a schematic diagram showing the configuration of a smoke detector in one embodiment. [Figure 3] is a diagram showing the configuration of a computer, which uses the hardware of a control unit as an embodiment. [Figure 4] is a diagram showing the functional configuration of a control unit in one embodiment. [Figure 5] is a diagram illustrating the structure of a table showing the steps of airflow change in one implementation mode. [Figure 6] is a diagram illustrating the structure of a temporary flow memory table in one embodiment. [Figure 7] is a diagram illustrating the structure of a flow record table in one embodiment. [Figure 8] is a diagram showing the composition of a value table of airflow change steps in a variation example. Implementation

[0016] [Implementation Mode]

[0017] The following describes a smoke sensor 1 according to one embodiment of the present invention. FIG1 is a diagram showing the configuration of the smoke detection system 1. The smoke detection system 1 includes a smoke sensor 11 and a high-order system 12.

[0018] The smoke sensor 11 is a device that is installed in the space of the monitored object where smoke is generated (hereinafter referred to as the "monitoring space"), and takes in the air in the monitoring space. If the air taken in contains smoke, it will detect the smoke and send a smoke alarm to the higher-level system 12 when smoke is detected.

[0019] In Figure 1, although the number of smoke sensors 11 in the smoke detection system 1 is one, the number of smoke sensors 11 in the smoke detection system 1 varies depending on the number or width of the monitored space.

[0020] The advanced system 12 can also be any of the following: a monitoring terminal device, a smoke alarm panel, a central monitoring system, etc. The advanced system 12 and the smoke sensor 11 can communicate with each other through wired, wireless, or hybrid communication media and can exchange data.

[0021] Since the higher-order system 12 is the same as the higher-order system of the prior art, its description is omitted.

[0022] Figure 2 is a schematic diagram showing the configuration of the smoke sensor 11. The smoke sensor 11 includes a housing 110, a light-emitting part 111, a light-receiving part 112, a fan 113, a filter 114, a flow meter 115, a button 116, a light-emitting part 117, and a control unit 118.

[0023] The housing 110 is a container that forms an internal space. The housing 110 has: an air intake P, which functions as an inlet for air to flow from the external space into the internal space; and an exhaust port Q, which functions as an outlet for air to flow from the internal space into the external space.

[0024] Furthermore, the housing 110 includes: a wall 1101, which forms a sensing area S within the interior space for sensing smoke; a pipe 1102, which forms an airflow path from the intake port P to the sensing area S; and a pipe 1103, which forms an airflow path from the sensing area S to the exhaust port Q.

[0025] The light-emitting part 111 has, for example, an LED, and emits light from the LED to the sensing area S. The light-receiving part 1112 is positioned away from the light-emitting part 111, so that the light emitted from the light-emitting part 111 is not directly incident, but is incident as scattered light from particles in the air within the sensing area S. The light-receiving part 112 has, for example, a photodiode, to receive a portion of the scattered light within the sensing area S, and outputs a light intensity signal indicating the intensity of the received light.

[0026] The fan 113 is positioned on the airflow path formed by the pipe 1102 and performs the following task: by rotating blades, it generates the flow of air from the external space toward the sensing area S.

[0027] The filter 114 is disposed in the airflow path formed by the pipe 1102 to capture dust contained in the air flowing from the outside space toward the sensing area S and to prevent dust from entering the sensing area S.

[0028] The flow meter 115 (an example of a flow measurement method) is a sensor that measures the flow rate of air flowing from the external space into the sensing area S by means of the operation of the fan 113. The flow meter 115 is equipped with, for example, a thermistor, and the air flow rate is specified based on the resistance value of the thermistor, which changes with the air flow rate. However, the method by which the flow meter 115 measures the air flow rate is not limited to this, and various known types of flow meters can also be used as the flow meter 115.

[0029] Button 116 (an example of an operation receiving means) is an operating device that accepts operations from users (e.g., the administrator of smoke sensor 1). Button 116 is operated when the user changes a set airflow change step value (an example of a limit value).

[0030] The light-emitting unit 117 is a component that performs the task of notifying the user that the operation of button 116 has been accepted. The light-emitting unit 117 has, for example, an LED, and responds to the user's operation of button 116 with different states corresponding to the set value of the airflow change step value. For example, it illuminates once when the airflow change step value is set to 10%, twice when it is set to 20%, and three times when it is set to 30%, thereby notifying the user of the set value.

[0031] In Figure 2, although the button 116 and the light-emitting part 117 are disposed on the outer side of the housing 110, their placement is not limited thereto. For example, if the housing 110 has an openable and closable cover, the button 116 can be disposed in a position within the interior space of the housing 110 where the cover is open and can be pressed down by the user, and the light-emitting part 117 can be disposed in a position within the interior space of the housing 110 where the cover is open and can be easily identified by the user. In this case, the deficiency of the airflow change step value setting being changed due to unintentional operation by the user can be avoided.

[0032] The control unit 118 is a device for controlling the operation of the smoke sensor 11. The hardware of the control unit 118 is, for example, a computer, and the control unit 118 is implemented by the computer performing processing according to the program used by the control unit 118.

[0033] Figure 3 shows the configuration of the computer 10, which is used as the hardware of the control unit 118. The computer 10 includes: a processor 101 for performing various data processing; a memory 102 for storing various data; an input / output interface 103 for receiving and transmitting signals with components such as the light-emitting part 111 of the smoke sensor 11; and a communication interface 104 for sending and receiving data with external devices (in this case, the high-level system 12).

[0034] Figure 4 is a diagram showing the functional configuration of the control unit 118. That is, the control unit 118, which has the configuration shown in Figure 4, is implemented by the computer 10 performing processing according to the program used by the control unit 118. The functional configuration of the control unit 118 will be described below.

[0035] Memory Technique 1180 is used to memorize various types of information. The information memorized using Memory Technique 1180 includes the following: (1) Options for airflow change step values ​​and a table representing the airflow change step values ​​selected and set from the options (hereinafter referred to as the "airflow change step value table"). (2) A table that temporarily stores the measured value of the flow meter 115 together with the time information indicating the time when the measured value was measured (hereinafter referred to as the "flow temporary memory table"). (3) A table that stores the measured values ​​in the flow temporary memory table when the rate of change has reached the set airflow change step value, together with the time information indicating the time when the measured value was measured (hereinafter referred to as "flow record table"). (4) The threshold value used to determine whether there is an abnormal flow. (5) The threshold value used to determine the presence or absence of smoke.

[0036] Figure 5 is a diagram illustrating the structure of the airflow change step value table. The data in the airflow change step value table shown in Figure 5 is from the options of three airflow change step values: 10%, 20%, and 30%. The 20% airflow change step value is currently selected.

[0037] Figure 6 illustrates the structure of a flow rate temporary memory table. The flow rate temporary memory table includes: a "Time" column, which stores time information indicating the moment the flow rate measurement was performed; and a "Flow Rate" column, which stores the flow rate measurement value at that moment. Only two records are stored in the flow rate temporary memory table.

[0038] The data in the first row of the flow temporary memory table represents the data last appended to the flow record table. The data in the second row of the flow temporary memory table represents the last flow measurement value obtained by the flow meter 115 and the time point after that measurement. Hereinafter, the measurement value stored in the "Flow" column of the first row of the flow temporary memory table will be referred to as f(1), and the measurement value stored in the "Flow" column of the second row of the flow temporary memory table will be referred to as f(2).

[0039] In this embodiment, the set airflow change step value and the rate of change (%) of the compared flow rate are represented by R in the following mathematical formula 1. R = |f(2) - f(1)| / f(1) × 100 …(Equation 1) Furthermore, |X| represents the absolute value of X.

[0040] When the rate of change R reaches the set airflow change step value, the data in the second row of the flow temporary memory table is appended to the bottom row of the flow record table, and the data in the first row of the flow temporary memory table is deleted, with the data in the second row becoming the new first row. Afterwards, the latest measurement value from the flow meter 115 and the data indicating the time since the measurement will be sequentially rewritten to the second row.

[0041] Figure 7 illustrates the structure of a flow record table. The flow record table includes: a "Time" column, which stores time information indicating the moment after the flow rate measurement; and a "Flow Rate" column, which stores the flow rate measurement value at that moment. The flow record table sequentially stores: the flow rate measurement value when the rate of change R of the airflow measured by the flow meter 115 reaches the set airflow change step value, and data indicating the time point at which that measurement value was measured.

[0042] Referring to Figure 4, the functional configuration of the control unit 118 will be further explained. The light-emitting indicator 1181 indicates that the light-emitting unit 111 is emitting light. The light intensity signal acquisition means 1182 acquires a light intensity signal representing the intensity of the light received by the light-receiving unit 112. The light intensity signal acquired by the light intensity signal acquisition means 1182 is used by the smoke detection means 1186.

[0043] The flow signal acquisition means 1183 acquires the flow signal representing the measured value of the flow meter 115. The measured value of the flow signal acquired by the flow signal acquisition means 1183, together with the time of acquisition, is temporarily stored in the flow temporary memory table of the memory means 1180.

[0044] The recording generation means 1184 generates recording data indicating the rate of change of the measured value of the flow meter 115 when it reaches a threshold value. Specifically, the recording generation means 1184 calculates the rate of change R based on the two measured values ​​(f(1) and f(2)) stored in the flow temporary memory table of the memory means 1180, according to the aforementioned mathematical formula 1, and determines whether the calculated rate of change R reaches the airflow change step value selected in the airflow change step value table. If the rate of change R reaches the selected airflow change step value, a copy of the second row of the flow temporary memory table is generated as new recording data, and this recording data is appended to the bottom row of the flow recording table. Furthermore, when the recording generation means 1184 appends new recording data to the flow recording table as described above, it deletes the data in the first row of the flow temporary memory table and uses the data in the second row as the new data in the first row.

[0045] The traffic anomaly detection method 1185 determines whether the measured value stored in the "Traffic" column of the second row of the traffic temporary memory table reaches the threshold value for determining traffic anomalies stored in the memory method 1180. If the measured value reaches the threshold value for determining traffic anomalies, traffic anomaly notification data is generated. The traffic anomaly notification data generated by the traffic anomaly detection method 1185 is sent to the higher-level system 12 via the communication method 1189.

[0046] The smoke detection means 1186 determines whether the intensity of the light intensity signal obtained by the light intensity signal acquisition means 1182 from the light-emitting unit 112 reaches the threshold value stored in the memory means 1180 for determining the presence or absence of smoke. If the intensity reaches the threshold value for determining the presence or absence of smoke, smoke occurrence notification data is generated. The smoke occurrence notification data generated by the smoke detection means 1186 is sent to the higher-level system 12 via the communication means 1189.

[0047] The limit value changing means 1187 changes the set airflow change step value. Specifically, the limit value changing means 1187 receives the operation signal output from the button 116 in response to the user's operation, and changes the record with "○" stored in the "Selection" column of the airflow change step value table of the memory means 1180 according to the received operation signal. For example, each time the user presses and holds the button 116, the record with "○" stored in the "Selection" column of the airflow change step value table will be changed sequentially in a cycle such as the first record, the second record, the third record, the first record, and so on.

[0048] The light-emitting indicator 1188 illuminates the light-emitting unit 117 in a manner corresponding to the number of the stored "○" record (i.e., the reset airflow change step value) each time a record with a "○" stored in the "Selection" column of the airflow change step value table changes. The example of the light-emitting unit 117 illuminating according to the light-emitting indicator 1188 is as described above.

[0049] Communication means 1189 (an example of a sending and receiving means) performs various data transmissions and receptions with the higher-level system 12. Specifically, as described above, communication means 1189 sends traffic anomaly notification data to the higher-level system 12 when traffic anomaly detection data is generated by traffic anomaly detection means 1185. Also, as described above, communication means 1189 sends smoke occurrence notification data to the higher-level system 12 when smoke occurrence notification data is generated by smoke detection means 1186.

[0050] For example, communication method 1189 receives a request to send a flow record table from higher-level system 12, and sends a copy of the flow record table to higher-level system 12 in response to the request. Higher-level system 12, or its user, analyzes, for example, changes in airflow over time based on the data stored in the flow record table received by higher-level system 12 from smoke sensor 11. This allows them to infer the cause when airflow has fallen outside the appropriate range, or to infer the period when airflow falls outside the appropriate range before it does.

[0051] The timing device 1190 continues to measure the current time and generates time information representing the current time after the measurement. The time information generated by the timing device 1190 may be used, for example, as time information stored in the "Time" column of a flow temporary memory table.

[0052] Based on the smoke detection system 1 described above, the user, by observing the recorded data stored in the flow rate log and determining that there is a waste of adding recorded data to the flow rate log at a high frequency, can increase the set airflow change step value by operating button 116. As a result, the deficiency of storing useless recorded data in the flow rate log can be reduced, and the memory capacity of the memory means 1180 can be used efficiently.

[0053] Furthermore, based on the aforementioned smoke detection system 1, the user, by observing the recorded data stored in the flow rate log, determines that if the frequency of adding records to the flow rate log is too low, they can reduce the set airflow change step value by operating button 116. As a result, the flow rate log can then store recorded data at an appropriate frequency, and the user can easily infer the cause of the aforementioned flow rate anomalies based on the recorded data.

[0054] [Example of variation] The above-described embodiments are specific examples of the present invention, and various changes can be made within the scope of the technical concept of the present invention. The following are examples showing such changes. Furthermore, two or more of the following variations can also be appropriately combined.

[0055] (1) In the above embodiment, although the operation receiving means for accepting user operations on the smoke detector 11 is assumed to be a button 116, the type of operation receiving means possessed by the smoke detector 11 is not limited to a button. For example, physical operating components of a different type than buttons, such as sliders or switches, can also be used as operation receiving means for the smoke detector 11. Furthermore, a touch screen can also be used as operation receiving means for the smoke detector 11. In this case, the operation receiving means is to display a virtual operating component on the screen and accept touch operations performed by the user on the virtual operating component.

[0056] (2) In the above-described embodiment, the limit value changing means 1187 changes the set airflow change step value in response to the user's operation received by the operation receiving means exemplified by button 116. Alternatively, or in addition, the limit value changing means 1187 may also change the set airflow change step value in response to data received by the communication means 1189 (an example of a receiving means) from the higher-level system 12 (an example of an external device).

[0057] For example, when a user performs a predetermined operation on the advanced system 12, the advanced system 12 requests the smoke sensor 11 to send an airflow change step value table, and the smoke sensor 11, in response to the request, sends a copy of the airflow change step value table to the advanced system 12.

[0058] The advanced system 12 displays a table of airflow change step values ​​received from the smoke sensor 11. When the user changes the airflow change step value selected in the displayed table of airflow change step values, the advanced system 12 generates an airflow change step value table with "○" stored in the "Selection" column of the record of the changed airflow change step value, and sends the airflow change step value table to the smoke sensor 11.

[0059] The smoke sensor 11 rewrites the airflow change step value table stored in the memory means 1180 using the airflow change step value table received from the high-level system 12. In this way, the airflow change step value selected by the user after operating the high-level system 12 will be reset in the smoke sensor 11.

[0060] In this variation, the user does not need to directly operate the smoke sensor 11, but can change the airflow change step value used in the smoke sensor 11.

[0061] (3) In the above-described embodiment, the limit value changing means 1187 changes the set airflow change step value according to the operation performed by the user. Alternatively, the limit value changing means 1187 can also change the set airflow change step value based on the measurement value of the flow meter 115 (an example of a flow measurement means).

[0062] In this variation, the memory means 1180 stores a value table of airflow change steps as illustrated in Figure 8, instead of the value table of airflow change steps shown in Figure 5. In this variation, each record in the value table of airflow change steps has an additional "flow range" column.

[0063] For example, the limit value change method 1187 is to update the airflow change step value table by storing the measured value in the "flow" column of the second row of the temporary flow memory table, that is, the airflow last measured by the flow meter 115, within which range shown in the "flow range" column of the airflow change step value table, and by storing "○" in the "selection" column of the record corresponding to the specified range.

[0064] Based on this example, for instance, when the airflow is low, even a small change in flow rate will still result in a larger rate of change R, the "Flow Rate Range" field stores records of smaller values ​​in the "Airflow Change Step Value" field and stores the range of high flow rates in the "Flow Rate Range" field. Conversely, the "Flow Rate Range" field stores records of larger values ​​in the "Airflow Change Step Value" field and stores the range of low flow rates in the "Flow Rate Range" field. This allows the system to automatically select the appropriate airflow change step value based on the current flow rate without manual intervention. This saves users time in selecting the appropriate airflow change step value.

[0065] In this variation, instead of the airflow change step value table, the formula representing the correspondence between the flow range and the airflow change step value can be stored in the memory means 1180 in advance, and the limit value change means 1187 can calculate the airflow change step value corresponding to the current flow according to the formula, and set the calculated airflow change step value.

[0066] (4) In the above implementation, although the selectable airflow change step value is assumed to be a discrete value such as 10%, 20%, 30%, the number of selectable airflow change step values ​​can be increased, and the airflow change step value can be set to be actually selected from continuous values.

[0067] (5) In the above embodiment, the airflow data generated in the smoke sensor 11 is stored in the airflow record table within the smoke sensor 11. Alternatively, or otherwise, the recorded data may be sent from the smoke sensor 11 to an external device (e.g., the high-level system 12) and stored in the external device.

[0068] (6) In the above-described embodiments, although the hardware of the control unit 118 is assumed to be a computer, the control unit 118 may also be configured as a dedicated device with integrated circuits such as ASIC (Application Specific Integrated Circuit) and FPGA (Field Programmable Gate Array).

[0069] 1: Smoke Detection System 10: Computer 11: Smoke Detector 12: Higher-order systems 101: Processor 102: Memory 103: Input / Output Interface 104: Communication Interface 110: Shell 111: Light-emitting part 112: Light-receiving part 113: Fan 114: Filter 115: Flow meter 116: Button 117: Light-emitting part 118: Control Unit 1101: Wall 1102, 1103: Pipe 1180: Memory Techniques 1181, 1188: Illuminated Indicator 1182: Methods for acquiring light intensity signals 1183: Methods for Obtaining Flow Signals 1184: Record Generation Methods 1185: Methods for Determining Traffic Anomalies 1186: Smoke Determination Methods 1187: Limit Value Change Methods 1189:Means of communication 1190: Timing Method P: Intake port Q: Exhaust port S: Sensing area

Claims

1. A smoke detector that senses the generation of smoke in the external space by sensing particles contained in air flowing into a sensing area from the external space, characterized by comprising: a flow rate measurement means for measuring the flow rate of air; a recording generation means for generating recording data indicating when the rate of change of the measured value of the flow rate measurement means has reached a threshold value; and a threshold value changing means for changing the threshold value.

2. The smoke detector as described in claim 1, wherein, It possesses: an operation receiving means for accepting user operations; and a boundary value changing means for changing the aforementioned boundary value in response to the operation received by the operation receiving means.

3. The smoke detector as described in claim 1, wherein, It has: a receiving means for receiving data from an external device; and the aforementioned limit value changing means for changing the aforementioned limit value in response to the data received by the aforementioned receiving means.

4. The smoke detector as described in claim 1, wherein, The aforementioned limit value change method is based on the measurement value of the aforementioned flow measurement method to change the aforementioned limit value.

5. The smoke detector as described in claim 4, wherein, The aforementioned limit value adjustment method is to increase the aforementioned limit value as the measured value of the aforementioned flow measurement method is smaller.

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