JP6681497B2 - Smoke sensor and smoke concentration estimation method - Google Patents

Description

  The present invention relates to a smoke sensor for detecting smoke and a smoke concentration estimation method.

2. Description of the Related Art Conventionally, a fire detector has been used as equipment for early detection of a fire occurrence and notifying residents and managers of a building where the fire has occurred of the fire occurrence to evacuate or extinguish the fire.
The fire detector includes a heat detector that detects a fire by heat and gives an alarm, and a smoke detector that detects a fire by smoke and gives an alarm.

Here, the configuration of the conventional smoke sensor will be described.
A conventional smoke sensor includes a case, a circuit board, a terminal board, electronic components mounted on the circuit board, a terminal board to which the circuit board is fixed, a bottom plate member, a plurality of labyrinths, and a insect screen. , A circuit board supporting member, a light emitting portion, and a light receiving portion (for example, see Patent Document 1).
The case accommodates a terminal board, a bottom plate member, a plurality of labyrinths, an insect screen, a circuit board support member, a smoke sensing chamber, a light emitting unit, and a light receiving unit.

The case has a plurality of smoke inlets for allowing smoke to flow into the case. The terminal board is a plate-shaped member and is fixed in the case. The terminal board is provided below the terminal board at a position where the bottom board member, the plurality of labyrinths, the insect screen, the circuit board support member, the smoke sensing chamber, the light emitting unit, and the light receiving unit can be accommodated.
The circuit board on which electronic components are mounted is fixed to the terminal board. The bottom plate member is arranged at the bottom of the case.

The plurality of labyrinths are erected on the upper surface of the outer peripheral portion of the bottom member in a state where smoke can be introduced into the central portion of the bottom plate member. The plurality of labyrinths has a function of suppressing entry of light from the outside.
The insect screen has a cylindrical shape and is arranged in the case so as to surround the plurality of labyrinths from the outside.
The circuit board support member is fixed to the lower side of the terminal board. The lower surface of the circuit board support member is connected to the upper ends of the plurality of labyrinths. The upper surface side of the circuit board support member supports the circuit board.
The smoke sensing chamber is a space defined by a bottom plate member, a circuit board support member, and a plurality of labyrinths. Smoke located outside the case enters the smoke sensing chamber through the smoke inlet, the insect screen, and the labyrinths.

The light emitting unit is provided below the circuit board and is electrically connected to the circuit board. The light emitting unit irradiates the smoke introduced into the smoke sensing chamber with light.
The light receiving portion is provided below the circuit board and is electrically connected to the circuit board. The light receiving unit receives the light emitted from the light emitting unit toward the smoke and scattered by the smoke. Among the electronic components mounted on the circuit board, the control electronic component calculates the smoke concentration in the smoke sensing chamber based on the light received by the light receiving unit.
The conventional smoke detector configured as described above issues an alarm when the calculated smoke concentration in the smoke detection chamber exceeds a predetermined threshold value.

JP, 2004-227446, A

  However, in the conventional smoke detector configured as described above, since the size of the opening of the smoke inlet is not so large, it is difficult for the smoke located outside the case to enter the case via the smoke inlet. For this reason, the smoke concentration in the smoke detection chamber becomes lower than the smoke concentration outside the case, and the smoke detector may delay detection of the occurrence of a fire.

Further, in the above-described conventional smoke detector, since the plurality of labyrinths and insect repellent nets are provided outside the smoke detection chamber, the smoke that has entered the case is unlikely to enter the smoke detection chamber.
Therefore, in the case of smoke detectors with multiple labyrinths and insect screens, the difference between the smoke concentration outside the case and the smoke concentration in the smoke detection chamber becomes even larger, so the smoke detector cannot detect a fire. There was a fear of further delay.
Particularly, when the velocity of the airflow flowing outside the case is low, the above problem becomes remarkable.

  Therefore, an object of the present invention is to provide a smoke detector and a smoke concentration estimation method capable of accurately detecting the occurrence of a fire by estimating the smoke concentration outside the case.

  In order to solve the above problems, according to one aspect of the present invention, a case, a smoke sensing chamber provided in the case, in which air including smoke flowing in and out of the case enters and leaves, and an outside of the case are provided. Based on the wind velocity of the flowing airflow, the inflow amount of the air containing the smoke that has flowed into the smoke detection chamber is calculated, and the inflow amount of the air containing the smoke, the capacity of the smoke detection chamber, and the inside of the smoke detection chamber. A smoke concentration estimating unit that estimates the concentration of smoke outside the case based on the concentration of smoke, is provided.

According to one aspect of the present invention, by including a smoke density estimation unit, the difference between the smoke density estimated by considering the wind speed of the airflow and the actual smoke density outside the case is reduced. It becomes possible.
In this way, by estimating the smoke concentration outside the case, it is possible to accurately detect a fire in the area where the smoke detector is installed.
Even if the velocity of the air flow is slow, it is possible to accurately detect a fire in the area where the smoke detector is installed.

The smoke concentration estimating unit may estimate the smoke concentration outside the case based on the following equation (1).
Dout (t) = (V / v) · {Din (t + Δt) −Din (t)} + Din (t)
... (1)
However, in the above formula (1), V is the capacity [m ³ ] of the smoke sensing chamber, v is the inflow amount [m ³ ] of air containing the smoke flowing into the smoke sensing chamber, and Din (t) is The smoke concentration [m ⁻¹ ] in the smoke sensing chamber at a certain time t, Dout (t) is the estimated smoke concentration [m ⁻¹ ] outside the case at a certain time t, and Δt is the certain time t. The elapsed time [s] from is shown respectively.

  As described above, by estimating the smoke concentration outside the case using the above equation (1), it is possible to accurately estimate the smoke concentration outside the case.

  In order to solve the above problems, according to another aspect of the present invention, the air containing smoke that has flowed into a smoke detection chamber provided in the case based on the wind speed of the airflow flowing outside the case of the smoke detector. And estimating the smoke concentration outside the case based on the inflow amount of air containing the smoke, the capacity of the smoke sensing chamber, and the smoke concentration in the smoke sensing chamber. A smoke concentration estimating method is provided.

  According to another aspect of the present invention, it is possible to accurately detect a fire in the area where the smoke detector is installed.

Further, the smoke concentration outside the case may be estimated based on the following equation (2).
Dout (t) = (V / v) · {Din (t + Δt) −Din (t)} + Din (t)
... (2)
However, in the above formula (2), V is the capacity [m ³ ] of the smoke sensing chamber, v is the inflow amount [m ³ ] of air containing the smoke flowing into the smoke sensing chamber, and Din (t) is The smoke concentration [m ⁻¹ ] in the smoke sensing chamber at a certain time t, Dout (t) is the estimated smoke concentration [m ⁻¹ ] outside the case at a certain time t, and Δt is the certain time t. The elapsed time [s] from is shown respectively.

  Thus, by substituting the inflow amount of air containing smoke into the smoke sensing chamber, the capacity of the smoke sensing chamber, and the smoke concentration in the smoke sensing chamber into the above equation (2), the smoke outside the case By estimating the concentration, it is possible to reduce the difference between the smoke concentration estimated in consideration of the wind speed of the air flow and the actual smoke concentration outside the case. This makes it possible to accurately detect a fire in the area where the smoke detector is installed.

  According to the present invention, it is possible to accurately detect the occurrence of a fire.

It is sectional drawing which shows schematic structure of the smoke sensor which concerns on the 1st Embodiment of this invention. It is the figure which planarly viewed the lower surface side of the smoke sensor of 1st Embodiment shown in FIG. It is the perspective view which decomposed | disassembled the case which comprises the smoke detector of 1st Embodiment, a bottom plate part, a plurality of labyrinths, insect nets, a circuit board support member, and a terminal board. 6 is a flowchart showing a process of a smoke density estimating method according to the first embodiment using the smoke sensor shown in FIG. 1. 8 is a flowchart showing a process of a smoke density estimating method according to a modification of the first embodiment using the smoke sensor shown in FIG. 1. It is sectional drawing which shows schematic structure of the smoke detector which concerns on the 2nd Embodiment of this invention. It is the figure which planarly viewed the lower surface side of the smoke detector of 2nd Embodiment shown in FIG. It is sectional drawing which shows schematic structure of the smoke detector which concerns on the 3rd Embodiment of this invention. It is the figure which planarly viewed from the lower surface the smoke detector of 3rd Embodiment shown in FIG. It is a graph which shows the relationship between the time and the heat generation temperature when only the first thermistor element is heated. It is a graph which shows the relationship between the time and heat generation temperature of the 2nd thermistor element when only the 1st thermistor element is made to generate heat. It is a graph which shows the time of a 3rd thermistor element at the time of making only a 1st thermistor element generate | occur | produce heat, and the relationship of heat-generating temperature. It is a graph which shows the time of the 4th thermistor element at the time of making only a 1st thermistor element heat-generate, and the relationship of heat-generating temperature.

  Hereinafter, embodiments to which the present invention is applied will be described in detail with reference to the drawings. It should be noted that the drawings used in the following description are for explaining the configuration of the embodiment of the present invention, and the sizes, thicknesses, dimensions, etc. of the respective parts shown in the drawings are not related to the dimensional relationship of the actual smoke sensor. May be different.

(First embodiment)
FIG. 1 is a sectional view showing a schematic configuration of a smoke sensor according to a first embodiment of the present invention. In FIG. 1, among the constituent elements of the smoke sensor 10 according to the first embodiment, constituent elements other than the control electronic component 23, the light emitting section 33, and the light receiving section 34 are illustrated in cross section. In addition, in FIG. 1, among the electronic components, only the control electronic component 23, which is an electronic component required for the description of the first embodiment, is mounted on the circuit board 31 as an example.
The arrow next to the airflow shown in FIG. 1 indicates an example of the moving direction (wind direction) of the airflow, but the wind direction of the airflow is not limited to this.

FIG. 2 is a plan view of the smoke detector according to the first embodiment shown in FIG. 2, the same components as those of the structure shown in FIG. 1 are designated by the same reference numerals.
FIG. 3 is an exploded perspective view of a case, a bottom plate portion, a plurality of labyrinths, an insect net, a circuit board support member, and a terminal board that constitute the smoke detector of the first embodiment. 3, the same components as those of the structure shown in FIGS. 1 and 2 are denoted by the same reference numerals.
1 to 3, as an example, a smoke detector 10 mounted on a ceiling (not shown) is illustrated.

  1 to 3, the smoke detector 10 according to the first embodiment includes a case 11, a terminal board 13, a circuit board support member 14, a bottom plate portion 15, a plurality of labyrinths 17, It has an insect screen 19, a smoke sensing chamber 22, a smoke concentration measuring mechanism 24 including a smoke concentration estimating unit, conductors 27 and 28, and a thermistor element 29 which is a wind velocity detecting unit.

The case 11 has a case body 35, a protrusion 36, and a smoke inlet 38. The case body 35 includes a terminal board 13, a circuit board support member 14, a bottom plate portion 15, a plurality of labyrinths 17, an insect net 19, a smoke sensing chamber 22, and a housing portion 35A capable of housing the smoke concentration measuring mechanism 24.
The terminal board 13 and the smoke concentration measuring mechanism 24 are accommodated in the upper portion of the case body 35, and the plurality of labyrinths 17 and the bottom plate portion 15 are accommodated in the lower portion of the case body 35.

  The projecting portion 36 projects upward from the upper portion inside the case body 35. The protruding portion 36 is inserted into a groove portion 42 formed on the outer peripheral portion of the terminal board 13 to regulate the position of the terminal board 13 in the case 11. As the protrusion 36, for example, a ring-shaped protrusion can be used.

The smoke inlet 38 is provided so as to penetrate the lower portion of the case main body 35 located below the position where the protrusion 36 is formed. A plurality of smoke inlets 38 are provided in the circumferential direction of the case body 35.
In the case of FIG. 2, eight smoke inlets 38 are illustrated as an example, but the number of smoke inlets 38 may be plural and is not limited to eight.
The smoke inlet 38 is an opening for allowing smoke-containing air flowing outside the case 11 to flow into the case body 35 when a fire occurs.

The terminal board 13 is a disk-shaped member, and has a groove 42, a protrusion 44, and a recess 46. The groove portion 42 is provided on the lower surface side of the outer peripheral portion of the terminal board 13. As described above, the protrusion 36 is inserted into the groove 42.
The projecting portion 44 projects downward from the lower surface side of the terminal board 13 and from the position inside the groove 42. The protruding portion 44 contacts the upper surface of the outer peripheral portion of the circuit board supporting member 14 that contacts the inner surface of the case body 35 when the groove portion 42 is inserted into the protruding portion 36. As a result, the protruding portion 44 regulates the position of the circuit board support member 14 within the accommodation portion 35A.
The recess 46 is formed by recessing the central portion of the terminal board 13 toward the ceiling (not shown).

  The circuit board support member 14 is a disk-shaped member whose diameter is smaller than the diameter of the terminal board 13. The circuit board support member 14 is housed in the housing portion 35A located below the terminal board 13. The circuit board support member 14 has a support surface 14a, a light emitting unit housing 51, and a light receiving unit housing 53.

The support surface 14a of the circuit board support member 14 is a flat surface protruding upward, and is in contact with the other surface 31b of the circuit board 31, which will be described later, which is a component of the smoke concentration measuring mechanism 24. As a result, the support surface 14a supports the other surface 31b side of the circuit board 31 arranged between the terminal board 13 and the circuit board support member 14.
The light emitting unit housing unit 51 houses the light emitting unit 33 so that the smoke sensing chamber 22 can be irradiated with the light emitted by the light emitting unit 33. The light receiving portion housing portion 53 houses the light receiving portion 34 so that the light emitted by the light emitting portion 33 to the smoke sensing chamber 22 can be received.

The bottom plate portion 15 is arranged near the bottom of the case body 35 so as to face the inner surface of the bottom of the case body 35.
The plurality of labyrinths 17 are provided on the outer peripheral portion of the upper surface of the bottom plate portion 15 so as to project above the upper surface of the bottom plate portion 15. The plurality of labyrinths 17 are configured integrally with the bottom plate portion 15. The upper ends of the plurality of labyrinths 17 are in contact with the lower surface of the circuit board support member 14.
The plurality of labyrinths 17 function as a light blocking member that suppresses the direct entry of light from the outside into the smoke sensing chamber 22.
The shape of the plurality of labyrinths 17 shown in FIG. 3 is an example, and is not limited to this shape.

The insect screen 19 is a ring-shaped member, and is arranged between the circuit board support member 14 and the bottom plate portion 15 so as to surround the outside of the plurality of labyrinths 17.
The smoke sensing chamber 22 is a space defined by the bottom plate portion 15, the circuit board support member 14 in a portion facing the bottom plate portion 15, and a plurality of labyrinths 17. The smoke detection chamber 22 is arranged in the lower part of the case body 35.
When a fire occurs, smoke-containing air enters and exits the smoke detection chamber 22 through the smoke inlet 38, the insect screen 19, and the plurality of labyrinths 17. The volume of the smoke sensing chamber 22 can be appropriately set within a range of 0.5 × 10 ⁻⁵ m ^{3 to} 5.0 × 10 ⁻⁵ m ³ , for example.

The smoke concentration measuring mechanism 24 is arranged above the smoke sensing chamber 22 in the case body 35. The smoke concentration measuring mechanism 24 measures the concentration of smoke flowing into the smoke sensing chamber 22 and estimates the concentration of smoke outside the case 11.
The smoke concentration measuring mechanism 24 includes a circuit board 31, a control electronic component 32 that also functions as a smoke concentration estimating unit, a light emitting unit 33, and a light receiving unit 34.

The circuit board 31 is housed in the case body 35. The circuit board 31 is arranged between the support surface 14 a of the circuit board support member 14 and the terminal board 13. The circuit board 31 has one surface 31a on which electronic components including the control electronic component 23 are mounted, and the other surface 31b provided on the opposite side of the one surface 31a.
The circuit board 31 can be composed of, for example, an insulating plate-shaped substrate body (not shown) and a wiring pattern (not shown) arranged on the one surface 31a side of the substrate body.
The wiring pattern (not shown) that constitutes the circuit board 31 includes a pair of external lines (external lines for power supply), a light emitting unit 33, a light receiving unit 34, and a control electronic component 23, which are not shown in FIGS. 1 to 3. It is electrically connected.
As the circuit board 31, for example, a printed wiring board can be used.

The control electronic component 32 is an electronic component that performs overall control of the smoke detector 10, and also functions as a smoke concentration estimation unit. The control electronic component 32 is electrically connected to the thermistor element 29, which is a wind speed detection unit, the circuit board 31, the light emitting unit 33, and the light receiving unit 34.
The smoke density estimation unit is configured to include a storage unit 61 and a control unit 62.
In the storage unit 61, air inflow amount calculation data (hereinafter, simply referred to as “air inflow amount”, which indicates a relationship between the magnitude of the wind velocity of the airflow acquired in advance and the inflow amount of air containing smoke flowing into the smoke sensing chamber 22. “Calculation data”), the capacity of the smoke sensing chamber 22, a predetermined smoke concentration (hereinafter, referred to as “predetermined concentration B”) that becomes a threshold value when starting detection of the wind speed of the airflow, and a threshold value when issuing an alarm. The program stores the alarm concentration, the program for detecting the concentration of smoke flowing into the smoke sensing chamber 22, the estimation program for estimating the concentration of smoke outside the case 11, and the like.

The control unit 62 controls the smoke detector 10 based on the program stored in the storage unit 61. For example, the control unit 62 detects the concentration of smoke that has flowed into the smoke detection chamber 22.
On the other hand, when the control electronic component 32 functions as a smoke concentration estimation unit, the control unit 62 is based on the air inflow amount calculation data and the temperature increase amount of the thermistor element 29 when the thermistor element 29 is heated. And calculates the inflow rate of smoke-containing air that has flowed into the smoke detection chamber 22, and determines the inflow rate of smoke-containing air, the capacity of the smoke detection chamber 22, and the smoke concentration in the smoke detection chamber 22. Based on this, the smoke concentration outside the case 11 is estimated.

  As described above, the inflow amount of the air containing smoke that has flowed into the smoke sensing chamber 22 is calculated based on the air inflow amount calculation data and the wind speed of the airflow detected by the thermistor element 29, and A smoke concentration estimating unit (control unit 62) for estimating the smoke concentration outside the case 11 based on the included air inflow, the capacity of the smoke detecting chamber 22, and the smoke concentration in the smoke detecting chamber 22. This makes it possible to reduce the difference between the smoke concentration estimated in consideration of the wind velocity of the air flow and the actual smoke concentration outside the case 11. Accordingly, it is possible to accurately detect a fire in the area where the smoke detector 22 is installed.

The smoke concentration estimating unit may estimate the smoke concentration outside the case 11 based on the following equation (5), for example.
Dout (t) = (V / v) · {Din (t + Δt) −Din (t)} + Din (t)
... (5)
However, in the above formula (5), V is a capacity [m ³ ] of the smoke sensing chamber, v is an inflow amount [m ³ ] of air containing the smoke flowing into the smoke sensing chamber, and Din (t) is The smoke concentration [m ⁻¹ ] in the smoke sensing chamber at a certain time t, Dout (t) is the estimated smoke concentration [m ⁻¹ ] outside the case at a certain time t, and Δt is the certain time t. The elapsed time [s] from is shown respectively.
The smoke density is generally expressed as the extinction rate [% / m] per part-way currency distance of light when light is transmitted through the smoke, but when expressed in SI units, the% disappears. And is represented by [m ⁻¹ ] as described above.

As described above, by estimating the smoke concentration outside the case 11 using the above equation (5), the smoke concentration outside the case 11 can be accurately estimated. For example, a CPU can be used.

The light emitting portion 33 is fixed to the light emitting portion housing portion 51, and is electrically connected to a wiring pattern (not shown) forming the circuit board 31. Thereby, the light emitting unit 33 is electrically connected to the control electronic component 32 via the wiring pattern.
The light emitting unit 33 irradiates the smoke sensing chamber 22 with light, and causes scattered light generated when the smoke particles flowing into the smoke sensing chamber 22 are exposed to the light receiving unit 34.
The light receiving section 34 is fixed to the light receiving section accommodating section 53 and receives the scattered light. Then, the control electronic component 32 calculates the concentration of smoke in the smoke sensing chamber 22 based on the scattered light received by the light receiving unit 34.

  The light emitting unit 33 and the light receiving unit 34 are, for example, the optical axis from the light emitting unit 33 toward the smoke sensing chamber 22, and the optical axis of scattered light scattered by the smoke particles in the smoke sensing chamber 22 toward the light receiving unit 34. Can be arranged so as to intersect at a predetermined angle in the horizontal direction and also at a predetermined angle in the vertical direction.

  Further, by providing a plurality of labyrinths 17 that shield light from the outside and a tubular insect net 19 that surrounds the outside of the labyrinths 17 below the smoke concentration measuring mechanism 24 described above, Since insects are less likely to enter the smoke sensing chamber 22, the wind speed of the airflow flowing outside the case 11 can be accurately obtained.

  One ends of the conductors 27 and 28 are electrically connected to a wiring pattern (not shown) forming the circuit board 31. The conductors 27 and 28 extend below the circuit board 31 so as to penetrate the circuit board support member 14 and the case body 35. As a result, the other ends of the conductors 27 and 28 are arranged outside the case 11.

The thermistor element 29 is a wind speed detection unit that detects the wind speed of the airflow flowing outside the case 11. The thermistor element 29 is provided between the other ends of the conductors 27 and 28. As a result, the thermistor element 29 is arranged outside the case body 35.
The thermistor element 29 continuously transmits data relating to the temperature at which heat is generated to the control electronic component 32.
As the thermistor element 29, for example, an NTC thermistor element is preferably used, but a PTC thermistor element may be used.

  As described above, by using one thermistor element 29 as the wind speed detection unit, the amount of heat taken by the airflow depends on the wind speed of the airflow. The wind speed of the airflow can be calculated.

FIG. 4 is a flowchart showing the processing of the smoke density estimating method according to the first embodiment using the smoke sensor shown in FIG.
With reference to FIG. 4, the smoke concentration estimating method according to the first embodiment (specifically, when the smoke in the smoke sensing chamber 22 sensed by the smoke sensor 10 exceeds a predetermined concentration B, Smoke density estimation method for detecting wind speed) will be described.

When the process shown in FIG. 4 is started, a smoke density detection process is performed in step S1. In the smoke concentration detecting step, a process of continuously detecting the smoke concentration in the smoke detecting chamber 22 is performed.
Subsequently, in step S2, it is determined whether or not the density of smoke in the smoke sensing chamber 22 exceeds a predetermined density B that is a threshold value. If it is determined in step S2 that the smoke density in the smoke sensing chamber 22 exceeds the predetermined density B (Yes), the process proceeds to step S3.
On the other hand, if it is determined in step S2 that the smoke concentration in the smoke detection chamber 22 does not exceed the predetermined concentration B (No), the process returns to step S1.
The predetermined concentration B can be appropriately set within the range of 0.001 [m ⁻¹ ] to 0.050 [m ⁻¹ ] for example.

In step S3, a wind speed acquisition step of acquiring the wind speed of the airflow flowing outside the case 11 is performed.
In the wind velocity acquisition step, for example, the temperature rise ΔT _Th [K] of the thermistor element 29 when one thermistor element 29 arranged so as to project to the outside of the case body 35 is heated, and the heat generation amount of the thermistor element 29. Substituting Q _Th [J], the amount of heat Q _FL [J] escaping to the smoke detector 10, and the heat capacity C _HC [J / K] of the thermistor element 29 into the following equation (6), the amount of heat taken by the air flow Q _AF A heat quantity calculating step for calculating [J], air inflow quantity calculating data showing a relationship between a size of the air stream and a heat quantity absorbed by the air stream, and a heat quantity Q lost by the air stream calculated in the heat quantity calculating step. _{Based on AF} [J], a wind speed acquisition step of acquiring the wind speed of the airflow is performed.
ΔT _Th = (Q _Th −Q _AF −Q _FL ) / C _HC (6)

The amount of heat taken by the airflow flowing outside the case 11 depends on the wind speed of the airflow. Therefore, it is possible to obtain the wind speed of the airflow flowing outside the case 11 from the amount of temperature rise of the thermistor element 29 when the current is passed to heat the thermistor element 29.
Therefore, the temperature rise ΔT _Th [K] of the thermistor element 29, the heat generation amount Q _Th [J] of the thermistor, the heat amount Q _FL [J] escaping to the smoke detector 10, and the heat capacity C _HC [J / K of the thermistor element 29. For calculating the amount of heat absorbed by the air flow Q _AF [J] and the amount of heat acquired by the air flow and the amount of heat absorbed by the air flow. Based on the data and the data, the wind speed of the airflow flowing outside the case 11 can be accurately calculated.
When the process of step S3 described above is completed, the process proceeds to step S4.

  In step S4, a smoke density estimation step is performed. In the smoke concentration estimation step, the inflow rate of air containing smoke that has flowed into the smoke sensing chamber 22 is calculated based on the air inflow rate calculation data acquired in advance and the wind speed of the airflow acquired in the wind speed acquisition step. In addition, by substituting the inflow amount of air containing smoke into the smoke sensing chamber 22, the capacity of the smoke sensing chamber 22, and the smoke concentration in the smoke sensing chamber 22 into the above equation (5), the case 11 Estimate the smoke concentration outside the.

In this way, when the smoke concentration in the smoke sensing chamber 22 that is continuously detected exceeds the preset predetermined concentration B, the air inflow amount calculation data and the wind speed of the airflow acquired in the wind speed acquisition step, Based on the above, the inflow amount of the smoke-containing air that has flowed into the smoke sensing chamber 22 is calculated, and the inflow amount of the smoke-containing air into the smoke sensing chamber 22, the capacity of the smoke sensing chamber 22, and the smoke. By substituting the smoke concentration in the sensing chamber 22 into the above equation (5), the smoke concentration outside the case 11 is estimated, and the smoke concentration estimated in consideration of the wind speed of the airflow and the case It is possible to reduce the difference between the actual smoke density outside 11 and the actual smoke density. As a result, it is possible to accurately detect a fire in the area where the smoke sensor 10 is installed.
When the process of step S4 described above is completed, the process proceeds to step S5.

In step S5, it is determined whether or not the smoke density estimated in step S4 exceeds a threshold alarm density. When it is determined in step S5 that the estimated smoke density exceeds the alarm density (Yes), the process proceeds to step S6.
On the other hand, if it is determined in step S5 that the estimated smoke concentration does not exceed the alarm concentration (determined as No), the process returns to step S4.

In step S6, a reporting process is performed. In the reporting process, a speaker (not shown) provided in the smoke detector 10 reports to notify that a fire has been detected.
In addition, by using a device such as a transistor or thyristor, a consumption current larger than the consumption current during normal monitoring is passed through the terminal part, so that the fact that a fire is detected is transmitted to the connected reception board (not shown). To do.
In this way, when the estimated smoke density exceeds the alarm density, by issuing an alarm, it is possible to make people in the room in which the smoke sensor 10 is installed recognize that a fire has occurred.
When the process of step S6 is completed, the process of the flowchart shown in FIG. 4 ends.

According to the smoke concentration estimating method of the first embodiment, the smoke concentration estimated outside the case 11 by using the above-described equation (5) is estimated in consideration of the wind velocity of the air flow. It is possible to reduce the difference between the density of the smoke and the actual smoke density outside the case 11. As a result, it is possible to accurately detect a fire in the area where the smoke sensor 10 is installed.
Further, when the detected smoke density exceeds a preset predetermined density B, the wind speed of the airflow flowing outside the case 11 is acquired, so that the wind speed of the airflow is constantly acquired. The electric power consumed by the smoke detector 10 can be saved as compared with the case where the heat is generated.

  FIG. 5 is a flowchart showing a process of a smoke density estimating method according to a modification of the first embodiment using the smoke sensor shown in FIG. 5, the same steps as those in the flowchart shown in FIG. 4 are designated by the same step numbers.

  With reference to FIG. 5, a smoke concentration estimation method according to the modified example of the first embodiment (specifically, a smoke concentration estimation method for continuously obtaining the wind velocity of the airflow) will be described.

  The smoke concentration estimating method according to the modified example of the first embodiment replaces the positions of step S2 and step S3 shown in FIG. 4 described above, and continuously and continuously in the wind speed acquisition step shown in FIG. The method similar to the smoke concentration estimation method of the first embodiment described with reference to FIG. 4 can be performed except that the wind velocity of the airflow flowing outside the case 11 is acquired.

  That is, in the smoke concentration estimation method according to the modification of the first embodiment, smoke detection is performed based on the air inflow amount calculation data acquired in advance and the wind speed of the airflow continuously acquired in the wind speed acquisition step. The inflow rate of smoke-containing air that has flowed into the chamber 22 is calculated, and the inflow rate of smoke-containing air, the capacity of the smoke sensing chamber 22, and the smoke concentration in the smoke sensing chamber 22 are calculated using the above equation (5). ), The smoke concentration outside the case 11 is always estimated.

  The smoke concentration estimating method according to the modified example of the first embodiment described above is the same as the smoke concentration estimating method according to the first embodiment described above except that the power consumption of the smoke sensor 10 is slightly increased. Similar effects can be obtained. That is, it is possible to accurately detect a fire in the area where the smoke detector 10 is installed.

  In the first embodiment, as an example, as shown in FIG. 1, the smoke sensing chamber 22 is arranged in the lower part of the case body 35, and the smoke concentration measuring mechanism 24 is arranged above the smoke sensing chamber 22. However, the smoke sensing chamber 22 may be disposed inside the case body 35, and the smoke concentration measuring mechanism 24 may be disposed adjacent to the smoke sensing chamber 22. The position is not limited to the positions of the smoke sensing chamber 22 and the smoke concentration measuring mechanism 24 shown in FIG. For example, the smoke sensing chamber 22 may be arranged above the case body 35.

Further, in the first embodiment, as an example, the case where the wind speed detecting unit is configured by one thermistor element 29 has been described, but the wind speed detecting unit may include, for example, three or less thermistor elements 29. Can be configured.
As described above, when the wind speed detection unit is configured by using two or three thermistor elements 29, the airflow detected by the wind speed detection unit is an average of the wind speeds of the airflows detected by these thermistor elements 29. Since the reliability of the accuracy of the obtained wind speed of the airflow is improved by using it as the wind speed of, the accuracy of the smoke concentration outside the estimated case 11 can be improved.

(Second embodiment)
FIG. 6 is a cross-sectional view showing a schematic configuration of a smoke detector according to the second embodiment of the present invention. 6, the same components as those of the smoke sensor 10 (see FIG. 1) of the first embodiment are designated by the same reference numerals.
FIG. 7 is a plan view of the smoke detector of the second embodiment shown in FIG. 6 viewed from the lower surface side. In FIG. 7, the same components as those of the structure shown in FIG. 6 are designated by the same reference numerals.

  Referring to FIGS. 6 and 7, the smoke detector 70 according to the second embodiment is replaced with the conductors 27 and 28 and the thermistor element 29 which constitute the smoke detector 10 according to the first embodiment. The smoke sensor 10 has the same configuration as that of the smoke detector 10 except that it has three atmospheric pressure detecting elements 71 that form a wind speed detecting unit.

The three atmospheric pressure detection elements 71 are electrically connected to the circuit board 31 and the control electronic component 32. The three atmospheric pressure detection elements 71 detect the pressure of the airflow flowing outside the case 11 and send data regarding the detected pressure of the airflow to the control electronic component 32.
As the atmospheric pressure detection element 71, for example, a MEMS type atmospheric pressure sensor can be used.
The three atmospheric pressure detecting elements 71 are, for example, inside a polygon (triangle 73 shown in FIG. 7) formed by connecting the centers of the atmospheric pressure detecting elements 71 arranged in adjacent positions with a straight line, It may be arranged so as to accommodate the center C of the main body 35.

According to the smoke sensor 70 of the second embodiment, inside the polygon (triangle 73 in this case) formed by connecting the centers of the atmospheric pressure detecting elements 71 arranged at the adjacent positions with a straight line, By disposing the three atmospheric pressure sensing elements 71 so as to accommodate the center C of the case body 35, the three atmospheric pressure sensing elements 71 are disposed only in a specific semicircle section in the circumferential direction of the outer surface of the case body 35. It will not be done.
Thereby, the wind direction of the airflow can be obtained as well as the wind speed of the airflow flowing outside the case 11 by the balance of the air pressures detected by the three air pressure detection elements 71 without depending on the direction of the airflow of the airflow.
Further, by knowing the wind direction of the air flow, the direction of the fire source viewed from the smoke sensor 70 can be estimated.
Further, the smoke detector 70 of the second embodiment configured as described above, like the smoke detector 10 of the first embodiment, detects a fire in the area where the smoke detector 70 is installed. It can be done accurately.
The smoke sensor 70 according to the second embodiment can determine the wind direction of the airflow based on the fact that the detected high atmospheric pressure side is upwind and the detected low atmospheric pressure side is downwind.

In the second embodiment, the case where the distance between the atmospheric pressure detecting elements 71 in the circumferential direction of the outer surface of the case body 35 is different has been described as an example, but the atmospheric pressure detection in the circumferential direction of the outer surface of the case body 35 is described. The distance between the elements 71 may be constant.
Further, in FIG. 7, as an example, the case where the wind speed detecting unit is configured by using the three atmospheric pressure detecting elements 71 has been described as an example, but the number of the atmospheric pressure detecting elements 71 configuring the wind speed detecting unit is three. As long as it is above, it is not limited to three.

Here, a smoke concentration estimating method according to the second embodiment using the smoke sensor 70 shown in FIG. 6 will be described.
The smoke concentration estimation method using the smoke sensor 70 is performed outside the case 11 by using the wind speed detection unit including the three atmospheric pressure detection elements 71 in the wind speed acquisition step of S3 shown in FIGS. 4 and 5 described above. A method similar to the smoke density estimation method shown in FIGS. 4 and 5 described in the first embodiment can be performed except that the wind speed and the wind direction of the airflow flowing through the airflow are acquired.

According to the smoke concentration estimation method of the second embodiment, the difference between the smoke concentration estimated in consideration of the wind speed and the wind direction of the airflow and the actual smoke concentration outside the case 11 should be reduced. Is possible. As a result, it is possible to accurately detect a fire in the area where the smoke sensor 70 is installed.
Further, by knowing the wind direction of the air flow, the direction of the fire source viewed from the smoke sensor 70 can be estimated.

(Third Embodiment)
FIG. 8 is a sectional view showing a schematic configuration of a smoke sensor according to the third embodiment of the present invention. In FIG. 8, the same components as those of the smoke detector 10 (see FIG. 1) of the first embodiment are designated by the same reference numerals.
FIG. 9 is a plan view of the smoke detector of the third embodiment shown in FIG. 8 viewed from the lower surface side. 9, the same components as those of the structure shown in FIG. 8 are designated by the same reference numerals.
8 and 9, four thermistor elements having the same configuration as the thermistor element 29 shown in FIGS. 1 and 2 are referred to as first to fourth thermistor elements 29-1 to 29-4 for convenience of description. Illustrate.

In addition, in FIGS. 8 and 9, the case where the wind direction of the airflow is in the direction from the first thermistor element 29-1 to the third thermistor element 29-3 is taken as an example.
The X direction shown in FIG. 9 is the arrangement direction of the first and third thermistor elements 29-1 and 29-3 and also indicates the wind direction of the air flow. The Y direction shown in FIG. 9 indicates the arrangement direction of the second and fourth thermistor elements 29-2 and 29-4.

  Referring to FIGS. 8 and 9, the smoke detector 80 according to the third embodiment is replaced with the thermistor element 29 included in the smoke detector 10 according to the first embodiment, and the first to the fourth. The thermistor elements 29-1 to 29-4 are provided and three pairs of conductors 27 and 28 are further provided, and the smoke sensor 10 has the same configuration as that of the smoke detector 10 of the first embodiment.

The four pairs of conductors 27 and 28 are arranged in a cross shape in plan view. One end of each of the four pairs of conductors 27 and 28 is electrically connected to the circuit board 31 and the control electronic component 32.
The four pairs of conductors 27 and 28 extend below the circuit board 31 and penetrate the case body 35. The other ends of the four pairs of conductors 27 and 28 are arranged outside the case body 35.

  The first thermistor element 29-1 is arranged between the other ends of the one conductor 27, 28 of the two pairs of conductors 27, 28 arranged in the X direction. The second thermistor element 29-2 is arranged between the other ends of the one conductor 27, 28 of the two pairs of conductors 27, 28 arranged in the Y direction.

  The third thermistor element 29-3 is arranged between the other ends of the other conductors 27 and 28 of the two pairs of conductors 27 and 28 arranged in the X direction. The fourth thermistor element 29-4 is arranged between the other ends of the other conductors 27, 28 of the two pairs of conductors 27, 28 arranged in the Y direction.

Accordingly, the first and third thermistor elements 29-1 and 29-3 are arranged so as to face each other in the X direction. The second and fourth thermistor elements 29-2 and 29-4 are arranged so as to face each other in the X direction.
The first to fourth thermistor elements 29-1 to 29-4 have, for example, a polygonal shape (in this case, a quadrangle 82) formed by connecting the centers of the thermistor elements arranged at adjacent positions with a straight line. It may be arranged inside so as to accommodate the center C of the case body 35 (see FIG. 9).

  As described above, by disposing the first to fourth thermistor elements 29-1 to 29-4, only one thermistor element among the first to fourth thermistor elements 29-1 to 29-4 is fixed. Heat is generated for a certain period of time, and data regarding the temperature change with time of the other thermistor element at this time is acquired. Based on the positional relationship of the other thermistor element with respect to the thermistor element and the wind direction of the airflow flowing outside the case 11, the wind direction and speed of the airflow can be obtained.

FIG. 10 is a graph showing the relationship between the heat generation temperature and the time when only the first thermistor element is heated. FIG. 11 is a graph showing the relationship between the heating temperature and the time of the second thermistor element when only the first thermistor element is heated.
FIG. 12 is a graph showing the relationship between the heating temperature and the time of the third thermistor element when only the first thermistor element is heated. FIG. 13 is a graph showing the relationship between the heat generation temperature and the time of the fourth thermistor element when only the first thermistor element is heated.
10 to 13, t ₁ is the time when the heat generation of the first thermistor element 29-1 is started (hereinafter referred to as “time t ₁ ”), and t ₂ is the heat generation of the first thermistor element 29-1. The stop time (hereinafter, referred to as “time t ₂ ”), t ₃ is affected by the heat generation of the first thermistor element 29-1, and the time when the third thermistor element 29-3 starts heat generation (hereinafter, referred to as “time t ₂ ”) , “Time t ₃ ”). The time t ₃ is a time located between the time t ₁ and the time t ₂ .

The heat generation temperature of the first thermistor element 29-1 shown in FIG. 10 is the reference value with the temperature of the first thermistor element 29-1 immediately before the first thermistor element 29-1 starts to generate heat as a reference value. Shows the temperature of the first thermistor after the start of heat generation when 0 is set to 0.
The heat generation temperature of the second thermistor element 29-2 shown in FIG. 11 is the reference value with the temperature of the second thermistor element 29-2 immediately before the first thermistor element 29-1 starts to generate heat as a reference value. Is the temperature of the second thermistor element 29-2 when is zero.
The heat generation temperature of the third thermistor element 29-3 shown in FIG. 12 is the reference value based on the temperature of the third thermistor element 29-3 immediately before the first thermistor element 29-1 starts to generate heat. Is the temperature of the third thermistor element 29-3 when 0 is set to zero.
The heat generation temperature of the fourth thermistor element 29-4 shown in FIG. 13 is the reference value with respect to the temperature of the fourth thermistor element 29-4 immediately before the first thermistor element 29-1 starts to generate heat. Is the temperature of the fourth thermistor element 29-4 when 0 is set to zero.

  Here, with reference to FIG. 8 to FIG. 13, a method of obtaining the wind direction of the airflow flowing outside the case 11 when the smoke detector 80 according to the third embodiment is used will be described.

_First , at time t ₁ , only the first thermistor element 29-1 is caused to generate heat, and when the time t ₂ is reached, the heat generation of the first thermistor element 29-1 is stopped.
The upper limit value of the heat generation temperature of the first thermistor element 29-1 at this time can be set to 5 ° C., for example.
As shown in FIG. 12, the first thermistor element 29-1 generates heat, so that the heat generation temperature rises. Here, looking at the heat generation temperatures from the time t ₁ to the time t ₂ shown in FIGS. 11 to 13, there is no change in the heat generation temperatures of the second and fourth thermistor elements 29-2 and 29-4. It can be seen that the third thermistor element 29-3 starts to generate heat at time t _{3 which} is later than time t ₁ . Further, it can be seen that the curve drawn by the heat generation temperature of the third thermistor element 29-3 has a shape obtained by reducing the size of the curve drawn by the heat generation temperature of the first thermistor element 29-1.
The time difference between time t ₁ and time t ₃ (= t ₁ −t ₃ ) is the difference in the distance between the first thermistor element 29-1 and the third thermistor element 29-3, and the outside of the case 11. It is considered that this is a time difference due to the speed of the airflow flowing through.
The time difference (= t ₁ −t ₃ ) is, for example, about 1 second.

  In addition, referring to FIG. 9, when the positional relationship between the first to fourth thermistor elements 29-1 to 29-4 is confirmed, the first and third thermistor elements 29-1 and 29-3 move in the X direction. The second and fourth thermistor elements 29-2 and 29-4 which are arranged are orthogonal to the X direction and which connect the first thermistor element 29-1 and the third thermistor element 29-3. It can be seen that they are arranged in the Y direction away from.

  Then, in the control electronic component 32, the heat generation temperature changes of the first to fourth thermistor elements 29-1 to 29-4 and the first thermistor element 29-1 that has generated heat and the second to the second that does not generate heat. Based on the positional relationship with the thermistor elements 29-2 to 29-4 of No. 4 and the wind direction of the airflow flowing outside the case 11.

  Specifically, in the case of the heat generation temperature change shown in FIGS. 10 to 13, there is no change in the heat generation temperature of the second and fourth thermistor elements 29-2 and 29-4, and the third thermistor element 29-3 is changed. Since the heat generation temperature rises at a temperature lower than the heat generation temperature of the first thermistor element 29-1, the wind direction of the air flow flowing outside the case 11 is from the first thermistor element 29-1 to the third direction. It is determined that the direction is the direction toward the thermistor element 29-3 (the direction of the arrow shown in FIGS. 8 and 9).

  In the case of the heat generation temperature changes shown in FIGS. 10 to 13, only the first thermistor element 29-1 is caused to generate heat, and the heat generation temperature changes of the first to fourth thermistor elements 29-1 to 29-4 are acquired. By doing so, the wind direction of the airflow can be specified, but depending on the wind direction of the airflow, at least one thermistor element among the second to fourth thermistor elements 29-2 to 29-4 is caused to generate heat one by one, It is necessary to acquire the heat generation temperature changes of the first to fourth thermistor elements 29-1 to 29-4.

According to the smoke detector of the third embodiment, the wind speed detector is configured by the first to fourth thermistor elements 29-1 to 29-4 provided in the circumferential direction of the outer surface of the case body 35. , The first to the fourth so as to accommodate the center of the case main body 35 inside a polygon (in this case, a quadrangle 82) formed by connecting the centers of the thermistor elements arranged adjacent to each other with a straight line. By arranging the thermistor elements 29-1 to 29-4, only one thermistor element is caused to generate heat for a certain period of time, and data regarding temperature changes with time of the other thermistor elements at this time is acquired, so Based on the heat generation temperature data with respect to time, the temperature data of other thermistor elements with respect to time, and the positional relationship of other thermistor elements with respect to the thermistor element that has generated heat. Te, without depending on the wind direction of the air flow flowing outside of the case 11, it is possible to determine the wind direction and wind speed of the airflow.
Further, by knowing the wind direction of the air flow, the direction of the fire source viewed from the smoke sensor 80 can be estimated.

Note that, in the third embodiment, as shown in FIG. 9, the case where the wind speed detection unit is configured by four thermistor elements has been described as an example, but the thermistor element that configures the wind speed detection unit is described. The number may be four or more, and is not limited to the number shown in FIG. 9.
In addition, by increasing the number of thermistor elements that configure the wind speed detection unit, the accuracy of the wind direction of the acquired airflow can be improved.

Next, a smoke density estimating method of the third embodiment using the smoke sensor 80 shown in FIG. 8 will be described.
The smoke concentration estimating method of the third embodiment using the smoke sensor 80 is performed from the first to fourth thermistor elements 29-1 to 29-4 in the wind velocity acquiring step of S3 shown in FIGS. 4 and 5. A method similar to the smoke concentration estimation method shown in FIGS. 4 and 5 described in the first embodiment, except that the wind speed and the wind direction of the airflow flowing outside the case 11 are acquired using the wind speed detection unit. Can be done by.

According to the smoke concentration estimating method of the third embodiment, the difference between the smoke concentration estimated in consideration of the wind speed and the wind direction of the air flow and the actual smoke concentration outside the case 11 should be reduced. Is possible. Thereby, it is possible to accurately detect a fire in the area where the smoke sensor 80 is installed.
Further, by knowing the wind direction of the air flow, the direction of the fire source viewed from the smoke sensor 80 can be estimated.

  As described above, the preferred embodiments of the present invention have been described in detail, but the present invention is not limited to such specific embodiments, and within the scope of the gist of the present invention described in the claims, Various modifications and changes are possible.

  10, 70, 80 ... Smoke detector, 11 ... Case, 13 ... Terminal board, 14 ... Circuit board support member, 14a ... Support surface, 15 ... Bottom plate part, 17 ... Labyrinth, 19 ... Insect screen, 22 ... Smoke detection chamber , 24 ... Smoke concentration measuring mechanism, 27, 28 ... Conductor, 29 ... Thermistor element, 31 ... Circuit board, 31a ... One surface, 31b ... Other surface, 32 ... Control electronic component, 33 ... Light emitting part, 34 ... Light receiving part, 35 ... Case body, 35A ... Housing part, 36, 44 ... Projection part, 38 ... Smoke inlet, 42 ... Groove part, 44 ... Projection part, 46 ... Recessed part, 51 ... Light emitting part housing part, 53 ... Light receiving part housing part, 61 ... Storage unit, 62 ... Control unit, 71 ... Atmospheric pressure detection element, 73, 82 ... Polygon, C ... Center

Claims (4)

A case,
A smoke sensing chamber provided in the case, in which air containing smoke flowing outside the case enters and leaves,
Based on the wind velocity of the airflow flowing outside the case, the inflow amount of the air containing the smoke that has flowed into the smoke sensing chamber is calculated, the inflow amount of the air containing the smoke, the capacity of the smoke sensing chamber, and Based on the smoke concentration in the smoke sensing chamber, a smoke concentration estimating unit that estimates the smoke concentration outside the case,
A smoke detector, comprising: The smoke detector according to claim 1, wherein the smoke concentration estimating unit estimates the smoke concentration outside the case based on the following equation (1).
Dout (t) = (V / v) · {Din (t + Δt) −Din (t)} + Din (t)
... (1)
However, in the above formula (1), V is the capacity [m ³ ] of the smoke sensing chamber, v is the inflow amount [m ³ ] of air containing the smoke flowing into the smoke sensing chamber, and Din (t) is The smoke concentration [m ⁻¹ ] in the smoke sensing chamber at a certain time t, Dout (t) is the estimated smoke concentration [m ⁻¹ ] outside the case at a certain time t, and Δt is the certain time t. The elapsed time [s] from is shown respectively.   Based on the wind speed of the airflow flowing outside the case of the smoke detector, the inflow amount of the air containing smoke that has flowed into the smoke detection chamber provided in the case is calculated, and the inflow amount of the air containing the smoke, A smoke concentration estimating method for estimating a smoke concentration outside the case based on a capacity of the smoke detecting chamber and a smoke concentration in the smoke detecting chamber. The smoke concentration estimating method according to claim 3, wherein the smoke concentration outside the case is estimated based on the following equation (2).
Dout (t) = (V / v) · {Din (t + Δt) −Din (t)} + Din (t)
... (2)
However, in the above formula (2), V is the capacity [m ³ ] of the smoke sensing chamber, v is the inflow amount [m ³ ] of air containing the smoke flowing into the smoke sensing chamber, and Din (t) is The smoke concentration [m ⁻¹ ] in the smoke sensing chamber at a certain time t, Dout (t) is the estimated smoke concentration [m ⁻¹ ] outside the case at a certain time t, and Δt is the certain time t. The elapsed time [s] from is shown respectively.

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