JP2019179034A - Smoke detector and method for estimating concentration of smoke - Google Patents

Abstract

To provide a smoke detector which can accurately detect generation of a fire by estimating the concentration of smoke outside a case, and a method for estimating the concentration of smoke.SOLUTION: The smoke detector includes: a case 11; a smoke detecting room 22 in the case 11, air containing smoke flowing outside the case 11 going into the room and out of the room; and a control electronic part 32 for calculating the amount of inflow of air including smoke flowing into the smoke detecting room 22 on the basis of the rate of air flowing outside the case 11, and estimating the concentration of smoke outside the case 11 based on the inflow amount of the air including smoke, the capacity of the smoke detecting room 22, and the concentration of the smoke in the smoke detecting room 22.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a smoke detector for detecting smoke and a smoke density estimation method.

Conventionally, a fire detector has been used as a facility for early detection of the occurrence of a fire and informing the residents and managers of the building where the fire has occurred to urge evacuation and extinguishing activities.
There are two types of fire detectors: a heat detector that detects a fire by heat and gives an alarm, and a smoke detector that detects a fire and detects an alarm by smoke.

Here, the configuration of a conventional smoke detector will be described.
A conventional smoke detector includes a case, a circuit board, a terminal board, an electronic component mounted on the circuit board, a terminal board to which the circuit board is fixed, a bottom plate member, a plurality of labyrinths, an insect net, And a circuit board support member, a light emitting portion, and a light receiving portion (for example, see Patent Document 1).
The case houses 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-like member and is fixed in the case. The terminal board is provided below the base plate member, the plurality of labyrinths, the insect net, the circuit board support member, the smoke sensing chamber, the light emitting unit, and the light receiving unit.
The circuit board on which the electronic components are mounted is fixed to the terminal board. The bottom plate member is disposed at the bottom in 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 have a function of suppressing entry of light from the outside.
The insect net has a cylindrical shape and is disposed 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 flows into the smoke detection chamber through the smoke inlet, the insect net, and the plurality of labyrinths.

The light emitting unit is provided below the circuit board and is electrically connected to the circuit board. The light emitting unit emits light to the smoke introduced into the smoke sensing chamber.
The light receiving unit is provided below the circuit board and is electrically connected to the circuit board. The light receiving unit receives light emitted from the light emitting unit toward the smoke and scattered by the smoke. Of 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 having the above-described configuration issues a warning when the calculated smoke concentration in the smoke detection chamber exceeds a predetermined threshold value.

JP 2004-227446 A

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

In addition, since the conventional smoke detector described above has a plurality of labyrinths and insect nets outside the smoke detection chamber, the smoke that has entered the case is difficult to enter the smoke detection chamber.
Therefore, in the case of smoke detectors with multiple labyrinths or insect screens, the difference between the smoke concentration outside the case and the smoke concentration in the smoke detection chamber is even greater, so that the smoke detector does not detect fire. There was a risk of delay.
In particular, the above problem becomes significant when the velocity of the airflow flowing outside the case is low.

  Accordingly, 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, there are provided a case, a smoke detection chamber provided in the case, in which air containing smoke flowing outside the case enters and exits, and an outside of the case. Based on the wind velocity of the flowing airflow, the inflow amount of the air containing the smoke flowing into the smoke sensing chamber is calculated, the inflow amount of the air containing the smoke, the capacity of the smoke sensing chamber, and the inside of the smoke sensing chamber There is provided a smoke detector, comprising a smoke density estimation unit for estimating a smoke density outside the case based on the smoke density.

According to one aspect of the present invention, by having 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.
Thus, 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 when the velocity of the airflow is slow, it is possible to accurately detect a fire in the area where the smoke detector is installed.

The smoke concentration estimation unit may estimate the smoke concentration outside the case based on the following formula (1).
Dout (t) = (V / v) · {Din (t + Δt) −Din (t)} + Din (t)
... (1)
However, in the above formula (1), V is a capacity [m ³ ] of the smoke sensing chamber, v is an inflow amount [m ³ ] of air including 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, the smoke concentration outside the case can be estimated with high accuracy by estimating the smoke concentration outside the case using the equation (1).

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

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

Moreover, you may estimate the smoke density | concentration in the outer side of the said case based on following formula (2).
Dout (t) = (V / v) · {Din (t + Δt) −Din (t)} + Din (t)
... (2)
However, in the above formula (2), V is a capacity [m ³ ] of the smoke sensing chamber, v is an inflow amount [m ³ ] of air including 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 amount of inflow of smoke-containing air 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), By estimating the density, it is possible to reduce the difference between the smoke density estimated in consideration of the wind speed of the airflow and the actual smoke density 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 detector which concerns on the 1st Embodiment of this invention. It is the figure which planarly viewed the smoke detector of 1st Embodiment shown in FIG. 1 from the lower surface side. It is the perspective view which decomposed | disassembled the case which comprises the smoke sensor of 1st Embodiment, a baseplate part, a some labyrinth, an insect net, a circuit board support member, and a terminal board. It is a flowchart which shows the process of the smoke density estimation method which concerns on 1st Embodiment using the smoke sensor shown in FIG. It is a flowchart which shows the process of the smoke density estimation method which concerns on the modification of 1st Embodiment using the smoke sensor shown in FIG. 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 smoke sensor of 2nd Embodiment shown in FIG. 6 from the lower surface side. 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 the smoke sensor of 3rd Embodiment shown in FIG. 8 from the lower surface. It is a graph which shows the relationship between the time at the time of making only the 1st thermistor element generate heat, and exothermic temperature. It is a graph which shows the relationship between the time of 2nd thermistor element at the time of making only the 1st thermistor element generate heat, and exothermic temperature. It is a graph which shows the relationship between the time of 3rd thermistor element at the time of making only 1st thermistor element generate heat, and exothermic temperature. It is a graph which shows the relationship between the time of the 4th thermistor element at the time of making only the 1st thermistor element generate heat, and exothermic temperature.

  Embodiments to which the present invention is applied will be described below in detail with reference to the drawings. The drawings used in the following description are for explaining the configuration of the embodiment of the present invention, and the size, thickness, dimension, etc. of each part shown in the figure are the dimensional relations of the actual smoke detector. May be different.

(First embodiment)
FIG. 1 is a cross-sectional view showing a schematic configuration of a smoke detector according to the first embodiment of the present invention. In FIG. 1, components other than the control electronic component 23, the light emitting unit 33, and the light receiving unit 34 among the components of the smoke detector 10 according to the first embodiment are illustrated in cross section. FIG. 1 illustrates an example in which only the control electronic component 23 that is an electronic component necessary for the description of the first embodiment is mounted on the circuit board 31 among the electronic components.
Moreover, although the arrow next to the airflow shown in FIG. 1 has shown an example of the moving direction (wind direction) of an airflow, the wind direction of an 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 in the structure shown in FIG.
FIG. 3 is an exploded perspective view of a case, a bottom plate portion, a plurality of labyrinths, an insect screen, a circuit board support member, and a terminal board constituting the smoke detector according to the first embodiment. 3, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals.
1-3, the smoke detector 10 attached to a ceiling (not shown) is illustrated as an example.

  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 part 15, a plurality of labyrinths 17, It has an insect net 19, a smoke sensing chamber 22, a smoke density measuring mechanism 24 including a smoke density estimating unit, conductors 27 and 28, and a thermistor element 29 which is a wind speed detecting unit.

The case 11 includes a case main body 35, a protrusion 36, and a smoke inlet 38. The case main body 35 has a housing part 35 </ b> A capable of housing the terminal board 13, the circuit board support member 14, the bottom plate part 15, the plurality of labyrinths 17, the insect screen 19, the smoke detection chamber 22, and the smoke concentration measurement mechanism 24.
The terminal board 13 and the smoke density measuring mechanism 24 are accommodated in the upper part of the case body 35, and the plurality of labyrinths 17 and the bottom plate part 15 are accommodated in the lower part of the case body 35.

  The protruding part 36 protrudes upward from the upper part in the case main body 35. The protruding portion 36 is inserted into a groove portion 42 formed on the outer peripheral portion of the terminal board 13, thereby restricting 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 part 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 the smoke inlets 38 may be plural, and is not limited to eight.
The smoke inlet 38 is an opening through which air containing smoke flowing outside the case 11 flows into the case body 35 when a fire occurs.

The terminal board 13 is a disk-shaped member and includes a groove part 42, a protruding part 44, and a concave part 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 protruding portion 36 is inserted into the groove portion 42.
The protruding portion 44 protrudes downward from a position on the lower surface side of the terminal board 13 and inside the groove 42. The protruding portion 44 is in contact with the upper surface of the outer peripheral portion of the circuit board support member 14 that is in contact with the inner surface of the case main body 35 in a state where the groove portion 42 is inserted into the protruding portion 36. Thereby, the protrusion part 44 has controlled the position of the circuit board support member 14 in 35 A of accommodating parts.
The concave portion 46 is configured by the central portion of the terminal board 13 being recessed 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 accommodated in the accommodating portion 35 </ b> A located below the terminal board 13. The circuit board support member 14 includes a support surface 14 a, a light emitting unit housing 51, and a light receiving unit housing 53.

The support surface 14 a of the circuit board support member 14 is a flat surface that protrudes upward, and is in contact with the other surface 31 b of a circuit board 31 that will be described later, which is a component of the smoke density measurement mechanism 24. Thus, the support surface 14a supports the other surface 31b side of the circuit board 31 disposed between the terminal board 13 and the circuit board support member 14.
The light emitting unit accommodating unit 51 accommodates the light emitting unit 33 so that light emitted from the light emitting unit 33 can be emitted to the smoke sensing chamber 22. The light receiving part accommodating part 53 accommodates the light receiving part 34 so that the light emitted from the light emitting part 33 can be received in the smoke sensing chamber 22.

The bottom plate portion 15 is disposed in the vicinity of the bottom portion of the case main body 35 so as to face the inner surface of the bottom portion of the case main 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 protrude upward from 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 light shielding members that suppress external light from directly entering the smoke sensing chamber 22.
In addition, the shape of the some labyrinth 17 shown in FIG. 3 is an example, Comprising: It is not limited to this shape.

The insect screen 19 is a ring-shaped member, and is disposed 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 a bottom plate portion 15, a portion of the circuit board support member 14 that faces the bottom plate portion 15, and a plurality of labyrinths 17. The smoke detection chamber 22 is disposed in the lower part of the case body 35.
When a fire occurs, smoke-containing air enters and exits the smoke sensing 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 density measuring mechanism 24 is disposed above the smoke sensing chamber 22 in the case main body 35. The smoke concentration measuring mechanism 24 measures the concentration of smoke flowing into the smoke sensing chamber 22 and estimates the smoke concentration outside the case 11.
The smoke density measurement mechanism 24 includes a circuit board 31, a control electronic component 32 that also functions as a smoke density estimation unit, a light emitting unit 33, and a light receiving unit 34.

The circuit board 31 is accommodated in the case body 35. The circuit board 31 is disposed 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 another surface 31b provided on the opposite side of the one surface 31a.
The circuit board 31 can be configured by, for example, an insulating plate-like substrate body (not shown) and a wiring pattern (not shown) arranged on the one surface 31a side of the substrate body.
A wiring pattern (not shown) constituting the circuit board 31 includes a pair of external lines (power supply external lines) not shown in FIGS. 1 to 3, a light emitting unit 33, a light receiving unit 34, and a control electronic component 23. Electrically connected.
For example, a printed wiring board can be used as the circuit board 31.

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

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

  In this way, the inflow amount of 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 the smoke A smoke concentration estimation unit (control unit 62) that estimates the smoke concentration outside the case 11 based on the inflow amount of air contained, the capacity of the smoke detection chamber 22, and the smoke concentration in the smoke detection chamber 22 is provided. Thus, the difference between the smoke concentration estimated in consideration of the wind speed of the airflow and the actual smoke concentration outside the case 11 can be reduced. Thereby, it is possible to accurately detect a fire in the area where the smoke detector 22 is installed.

For example, the smoke density estimation unit may estimate the smoke density outside the case 11 based on the following equation (5).
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 including 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.
The smoke concentration is generally expressed in terms of the light extinction rate per unit currency distance [% / m] when the light is transmitted through the smoke, but the percentage disappears when expressed in the SI unit system. As described above, it is expressed by [m ⁻¹ ].

Thus, 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 part 33 is fixed to the light emitting part accommodating part 51 and is electrically connected to a wiring pattern (not shown) constituting the circuit board 31. Thereby, the light emission part 33 is electrically connected with the electronic component 32 for control via the wiring pattern.
The light emitting unit 33 irradiates the smoke sensing chamber 22 with light, and causes scattered light generated when the light hits the smoke particles flowing into the smoke sensing chamber 22 to enter the light receiving unit 34.
The light receiving unit 34 is fixed to the light receiving unit receiving unit 53 and receives the scattered light. Then, the control electronic component 32 calculates the smoke concentration 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 include, for example, an optical axis from the light emitting unit 33 toward the smoke sensing chamber 22 and an optical axis of scattered light that is scattered by the smoke particles in the smoke sensing chamber 22 and 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 having a plurality of labyrinths 17 for shielding light from outside and a cylindrical insect net 19 surrounding the outside of the plurality of labyrinths 17 below the smoke concentration measuring mechanism 24 described above, Since insects are unlikely to enter the smoke sensing chamber 22, the wind speed of the airflow flowing outside the case 11 can be obtained with high accuracy.

  One end of each of the conductors 27 and 28 is electrically connected to a wiring pattern (not shown) constituting 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 main body 35. Thereby, the other end portions of the conductors 27 and 28 are disposed outside the case 11.

The thermistor element 29 is a wind speed detector 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. Thereby, the thermistor element 29 is arranged outside the case body 35.
The thermistor element 29 continuously transmits data related to the temperature when 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.

  Thus, since the amount of heat taken away by the airflow depends on the wind speed of the airflow by using one thermistor element 29 as the wind speed detection unit, the temperature rise amount of the thermistor element 29 when the thermistor element 29 is heated is determined. The wind speed of the air current can be obtained.

FIG. 4 is a flowchart showing the process of the smoke concentration estimation method according to the first embodiment using the smoke detector shown in FIG.
Referring to FIG. 4, the smoke concentration estimation method according to the first embodiment (specifically, when the smoke in the smoke detection chamber 22 detected by the smoke detector 10 exceeds a predetermined concentration B, The smoke density estimation method when detecting the wind speed) will be described.

When the process shown in FIG. 4 is started, a smoke density detection step is performed in step S1. In the smoke concentration detection process, a process of continuously detecting the smoke concentration in the smoke detection chamber 22 is performed.
In the subsequent step S2, it is determined whether or not the smoke concentration in the smoke sensing chamber 22 exceeds a predetermined concentration B that is a threshold value. If it is determined in step S2 that the smoke concentration in the smoke sensing chamber 22 exceeds the predetermined concentration B (determined as 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 sensing chamber 22 does not exceed the predetermined concentration B (determined No), the process returns to step S1.
The predetermined concentration B, for ^example, can be appropriately set within a range of ^{0.001 [m -1] ~0.050 [m} -1].

In step S <b> 3, a wind speed acquisition process for acquiring the wind speed of the airflow flowing outside the case 11 is performed.
In the wind speed acquisition step, for example, the temperature rise ΔT _Th [K] of the thermistor element 29 when one thermistor element 29 arranged so as to protrude to the outside of the case body 35 is heated, and the amount of heat generated by the thermistor element 29 element. 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 are substituted into the following equation (6), and the amount of heat Q _AF lost to the airflow A heat quantity calculation step for calculating [J], an air inflow amount calculation data indicating a relationship between a previously acquired airflow size and a heat amount taken by the airflow, and a heat amount Q taken by the airflow calculated in the heat amount calculation 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 away by the airflow flowing outside the case 11 depends on the wind speed of the airflow. For this reason, it is possible to determine the wind speed of the airflow flowing outside the case 11 from the amount of temperature increase of the thermistor element 29 when the thermistor element 29 is heated by passing an electric current.
Therefore, the temperature rise ΔT _Th [K] of the thermistor element 29, the calorific value Q _Th [J] of the thermistor, the heat quantity 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 air inflow amount indicating the relationship between the amount of heat Q _AF [J] deprived by the air flow calculated by substituting the above equation (6) and the amount of heat acquired in advance and the amount of heat deprived by the air flow Based on 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 amount of air including smoke flowing into the smoke sensing chamber 22 is calculated based on the air inflow amount calculation data acquired in advance and the wind speed of the airflow acquired in the wind speed acquisition step. In addition, by substituting the amount of inflow of air containing smoke into the smoke sensing chamber 22, the capacity of the smoke sensing chamber 22, and the concentration of smoke in the smoke sensing chamber 22 into the above equation (5), the case 11 Estimate the smoke concentration outside of.

Thus, when the smoke concentration in the smoke sensing chamber 22 that is continuously detected exceeds a predetermined concentration B set in advance, the air inflow amount calculation data, and the wind speed of the airflow obtained in the wind speed obtaining step, Based on the above, the inflow amount of the air including the smoke flowing into the smoke detection chamber 22 is calculated, the inflow amount of the air including the smoke into the smoke detection chamber 22, the capacity of the smoke detection chamber 22, and the smoke By substituting the smoke concentration in the sensing chamber 22 into the above equation (5), the smoke concentration estimated in consideration of the wind speed of the airflow by estimating the smoke concentration outside the case 11 and the case It is possible to reduce the difference between the actual smoke density outside of 11. Thereby, it is possible to accurately detect a fire in an area where the smoke detector 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 concentration estimated in step S4 has exceeded the alarm concentration that is a threshold value. If it is determined in step S5 that the estimated smoke concentration has exceeded the alarm concentration (determined as 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 No), the process returns to step S4.

In step S6, a reporting process is performed. In the notification process, a notification is given from a speaker (not shown) provided in the smoke detector 10 in order to notify that a fire has been detected.
In addition, by using a device such as a transistor or thyristor, a current consumption larger than the current consumption during normal monitoring is passed through the terminal section, so that the connected reception board (not shown) is informed that a fire has been detected. To do.
As described above, when the estimated smoke concentration exceeds the alarm concentration, it is possible to make people in the room where the smoke detector 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 estimation method of the first embodiment, the smoke estimated in consideration of the wind speed of the airflow by estimating the smoke concentration outside the case 11 using the above-described equation (5). And the difference between the actual smoke concentration outside the case 11 can be reduced. Thereby, it is possible to accurately detect a fire in an area where the smoke detector 10 is installed.
In addition, when the detected smoke density exceeds a predetermined density B set in advance, the thermistor element 29 is used to obtain the wind speed of the airflow at all times by obtaining the wind speed of the airflow flowing outside the case 11. As compared with the case where the heat is generated, the power consumed by the smoke detector 10 can be saved.

  FIG. 5 is a flowchart showing the processing of the smoke concentration estimation method according to the modification of the first embodiment using the smoke detector shown in FIG. In FIG. 5, the same steps as those in the flowchart shown in FIG.

  With reference to FIG. 5, a smoke concentration estimation method according to a modification of the first embodiment (specifically, a smoke concentration estimation method for continuously acquiring the wind speed of an air flow) will be described.

  In the smoke concentration estimation method according to the modification of the first embodiment, the positions of step S2 and step S3 shown in FIG. 4 described above are interchanged, and in the wind speed acquisition step shown in FIG. Other than acquiring the wind speed of the airflow flowing outside the case 11, the same method as the smoke concentration estimation method of the first embodiment described in FIG. 4 can be used.

  That is, in the smoke concentration estimation method according to the modified example 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 process. The inflow amount of air containing smoke that has flowed into the chamber 22 is calculated, and the inflow amount of air containing smoke, the capacity of the smoke detection chamber 22, and the concentration of smoke in the smoke detection chamber 22 are calculated using the above equation (5). ), The smoke concentration outside the case 11 is always estimated.

  The smoke concentration estimation method according to the modification of the first embodiment described above is the same as the smoke concentration estimation method of the first embodiment described above, except that the power consumption of the smoke detector 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 disposed in the lower part of the case body 35, and the smoke concentration measuring mechanism 24 is disposed above the smoke sensing chamber 22. However, the smoke sensing chamber 22 may be disposed in the case body 35, and the smoke concentration measuring mechanism 24 may be disposed adjacent to the smoke sensing chamber 22. The position of the smoke sensing chamber 22 and the smoke density measurement mechanism 24 shown in FIG. For example, the smoke detection chamber 22 may be disposed on the upper portion of the case body 35.

In the first embodiment, as an example, the case where the wind speed detection unit is configured by one thermistor element 29 has been described as an example. However, for example, the wind speed detection unit includes 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 obtained by averaging the wind speeds of the airflows detected by these thermistor elements 29. Since the reliability of the accuracy of the wind speed of the obtained airflow is improved, 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. In FIG. 6, the same components as those of the smoke detector 10 (see FIG. 1) of the first embodiment are denoted by the same reference numerals.
FIG. 7 is a plan view of the smoke detector according to the second embodiment shown in FIG. 6 from the lower surface side. In FIG. 7, the same components as those in the structure shown in FIG.

  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 constituting the smoke detector 10 of the first embodiment. The smoke detector 10 is configured in the same manner except that it includes three barometric pressure detecting elements 71 constituting 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 transmit data regarding the detected airflow pressure to the control electronic component 32.
As the atmospheric pressure detecting element 71, for example, a MEMS type atmospheric pressure sensor can be used.
For example, the three atmospheric pressure detection elements 71 are arranged inside a polygon (in this case, a triangle 73 shown in FIG. 7) formed by connecting the centers of the atmospheric pressure detection elements 71 arranged at adjacent positions with a straight line. It is good to arrange | position so that the center C of the main body 35 may be accommodated.

According to the smoke detector 70 of the second embodiment, inside the polygon (in this case, the triangle 73) formed by connecting the centers of the atmospheric pressure detection elements 71 arranged at adjacent positions with a straight line, By arranging the three atmospheric pressure detection elements 71 so as to accommodate the center C of the case main body 35, the three atmospheric pressure detection elements 71 are arranged only in a specific semicircular section in the circumferential direction of the outer surface of the case main body 35. It will not be done.
As a result, not only the wind direction of the airflow but also the wind direction of the airflow as well as the wind speed of the airflow flowing outside the case 11 can be obtained by the balance of the atmospheric pressure detected by the three atmospheric pressure detecting elements 71 without depending on the direction of the airflow direction.
Moreover, the direction of the fire source seen from the smoke detector 70 can be estimated by knowing the wind direction of the airflow.
Further, the smoke detector 70 of the second embodiment configured as described above detects fire in the area where the smoke detector 70 is installed, similarly to the smoke detector 10 of the first embodiment. It can be performed with high accuracy.
Note that the smoke detector 70 of the second embodiment can determine the wind direction of the airflow based on the fact that the side with the higher atmospheric pressure to be detected is on the windward side and the side with the lower atmospheric pressure to be detected is on the leeward side.

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

Here, the smoke density estimation method of the second embodiment using the smoke detector 70 shown in FIG. 6 will be described.
The smoke density estimation method using the smoke detector 70 uses the wind speed detection unit composed of the three atmospheric pressure detection elements 71 in the wind speed acquisition process of S3 shown in FIGS. 4 except that the wind speed and direction of the airflow flowing through the airflow are acquired by the same method as the smoke concentration estimation method shown in FIGS. 4 and 5 described in the first embodiment.

According to the smoke density estimation method of the second embodiment, the difference between the smoke density estimated in consideration of the wind speed and direction of the airflow and the actual smoke density outside the case 11 is reduced. Is possible. Thereby, it is possible to accurately detect a fire in the area where the smoke detector 70 is installed.
Moreover, the direction of the fire source seen from the smoke detector 70 can be estimated by knowing the wind direction of the airflow.

(Third embodiment)
FIG. 8 is a cross-sectional view showing a schematic configuration of a smoke detector 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 denoted by the same reference numerals.
FIG. 9 is a plan view of the smoke detector according to the third embodiment shown in FIG. In FIG. 9, the same components as those of the structure shown in FIG.
In FIG. 8 and FIG. 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 explanation. Illustrated.

8 and 9 exemplify a case in which the airflow direction of the airflow coincides with the direction from the first thermistor element 29-1 to the third thermistor element 29-3.
The X direction shown in FIG. 9 is the arrangement direction of the first and third thermistor elements 29-1 and 29-3 and indicates the wind direction of the airflow. Further, 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 replaces the thermistor element 29 constituting the smoke detector 10 of the first embodiment with the first to fourth. The thermistor elements 29-1 to 29-4 and the three pairs of conductors 27 and 28 are further provided, and the configuration is the same 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 disposed outside the case body 35.

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

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

Thereby, the 1st and 3rd thermistor elements 29-1 and 29-3 are arrange | positioned so that it may oppose in a 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 are, for example, polygonal (in this case, a square 82) formed by connecting the centers of the thermistor elements arranged at adjacent positions with a straight line. It is good to arrange | position so that the center C of the case main body 35 may be accommodated inside (refer FIG. 9).

  As described above, by arranging the first to fourth thermistor elements 29-1 to 29-4, only one thermistor element is fixed among the first to fourth thermistor elements 29-1 to 29-4. Heat is generated for a period of time, and data on the temperature change with respect to the time of the other thermistor element is obtained. Based on the positional relationship of the other thermistor elements with respect to the thermistor elements, the wind direction and the wind speed of the air current can be obtained without depending on the wind direction of the air stream flowing outside the case 11.

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

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

  Here, with reference to FIGS. 8 to 13, a description will be given of how to determine the wind direction of the airflow flowing outside the case 11 when the smoke detector 80 according to the third embodiment is used.

Initially, at time _{t 1,} to generate heat only the first thermistor element 29-1, stops the heating of the first thermistor element 29-1 at the stage became time _{t 2.}
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, thereby increasing the heat generation temperature. Turning now to the heat generation temperature of between 11 to 13 are shown the time _{t 1} from the time _{t 2,} the heating temperature of the second and fourth thermistor element 29-2,29-4 but no change in the third thermistor element 29-3, it can be seen that the start of the heating from the time t ₃ when delayed from time t _1. It can also be seen that the curve drawn by the heat generation temperature of the third thermistor element 29-3 is a shape obtained by reducing the size of the curve drawn by the heat generation temperature of the first thermistor element 29-1.
Note that the time difference (= t ₁ −t ₃ ) between time t ₁ and time t ₃ is the difference in distance between the first thermistor element 29-1 and the third thermistor element 29-3 and the outside of the case 11. It is thought that this is the time difference due to the speed of the airflow flowing through.
The time difference (= t ₁ −t ₃ ) is, for example, about 1 second.

  Further, 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, 29-3 are moved in the X direction. The second and fourth thermistor elements 29-2 and 29-4 are arranged to be orthogonal to the X direction and 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 that is separated from the center.

  Then, in the control electronic component 32, the heat generation temperature change of the first to fourth thermistor elements 29-1 to 29-4 and the second to second heat sources that have not generated heat with the generated first thermistor element 29-1. Based on the positional relationship with the four thermistor elements 29-2 to 29-4, the wind direction of the airflow flowing outside the case 11 is determined.

  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 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 airflow flowing outside the case 11 is changed from the first thermistor element 29-1 to the third. It is determined that the direction is toward the thermistor element 29-3 (the arrow direction shown in FIGS. 8 and 9).

  10 to 13, only the first thermistor element 29-1 is heated to obtain the heat generation temperature changes of the first to fourth thermistor elements 29-1 to 29-4. 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 of the second to fourth thermistor elements 29-2 to 29-4 is heated one by one, It is necessary to acquire changes in heat generation temperature 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 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 at adjacent positions with straight lines. By disposing the thermistor elements 29-1 to 29-4, only one thermistor element is heated for a certain period of time, and data relating to the temperature change with respect to the time of the other thermistor elements at this time is obtained. Based on heat generation temperature data with respect to time, temperature data with respect to time of other thermistor elements, and positional relationship of other thermistor elements with respect to the generated thermistor elements. 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.
In addition, the direction of the fire source viewed from the smoke detector 80 can be estimated by knowing the wind direction of the airflow.

In the third embodiment, as illustrated in FIG. 9, as an example, the case where the wind speed detection unit is configured with four thermistor elements has been described as an example. However, the thermistor elements that configure the wind speed detection unit are described as an example. The number should just be four or more, and is not limited to the number shown in FIG.
Moreover, the precision of the wind direction of the acquired airflow can be improved by increasing the number of thermistor elements which comprise a wind speed detection part.

Next, a smoke density estimation method according to the third embodiment using the smoke detector 80 shown in FIG. 8 will be described.
The smoke density estimation method of the third embodiment using the smoke detector 80 is based on the first to fourth thermistor elements 29-1 to 29-4 in the wind speed acquisition process of S3 shown in FIGS. 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 direction of the airflow flowing outside the case 11 are acquired using the wind speed detection unit. Can be performed.

According to the smoke density estimation method of the third embodiment, the difference between the smoke density estimated in consideration of the wind speed and direction of the airflow and the actual smoke density outside the case 11 is reduced. Is possible. Thereby, it is possible to accurately detect a fire in an area where the smoke detector 80 is installed.
In addition, the direction of the fire source viewed from the smoke detector 80 can be estimated by knowing the wind direction of the airflow.

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

  DESCRIPTION OF SYMBOLS 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 net, 22 ... Smoke detection chamber 24 ... Smoke density measuring mechanism, 27, 28 ... Conductor, 29 ... Thermistor element, 31 ... Circuit board, 31a ... One side, 31b ... Other side, 32 ... Control electronic component, 33 ... Light emitting part, 34 ... Light receiving part, 35 ... Case body, 35A ... Accommodating portion, 36,44 ... projection, 38 ... Smoke inlet, 42 ... groove, 44 ... projection, 46 ... concave, 51 ... light emitting portion accommodation, 53 ... light receiving portion accommodation, 61 ... Storage unit, 62 ... Control unit, 71 ... Barometric pressure sensing element, 73, 82 ... Polygon, C ... Center

Claims (4)

Case and
A smoke sensing chamber provided inside the case, through which air containing smoke flowing outside the case enters and exits;
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 A smoke density estimation unit for estimating a smoke density outside the case based on the smoke density in the smoke sensing chamber;
A smoke detector. The smoke detector according to claim 1, wherein the smoke density estimation unit estimates the smoke density outside the case based on the following formula (1).
Dout (t) = (V / v) · {Din (t + Δt) −Din (t)} + Din (t)
... (1)
However, in the above formula (1), V is a capacity [m ³ ] of the smoke sensing chamber, v is an inflow amount [m ³ ] of air including 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.   Based on the wind speed of the airflow flowing outside the case of the smoke detector, calculate the inflow amount of air containing smoke flowing into the smoke detection chamber provided in the case, the inflow amount of air containing the smoke, A smoke density estimation method for estimating a smoke density outside the case based on a capacity of the smoke sensing room and a density of the smoke in the smoke sensing room. The smoke density estimation method according to claim 3, wherein the smoke density outside the case is estimated based on the following formula (2).
Dout (t) = (V / v) · {Din (t + Δt) −Din (t)} + Din (t)
... (2)
However, in the above formula (2), V is a capacity [m ³ ] of the smoke sensing chamber, v is an inflow amount [m ³ ] of air including 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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