JP2019070992A - Fire alarm system - Google Patents

Abstract

To provide a fire alarm system capable of eliminating erroneous notification of occurrence of a fire in a terrible environment, in which a large volume of dust or oil mist disperses, such as a cement plant, recycling factory, or iron mill, and highly precisely detecting minute smoke generated at an early stage of the fire.SOLUTION: A fire alarm system 1 of the present invention includes a water filter 10 that is disposed at an entrance 3a of a duct 3 used for exhaust, and designed to form a layer of bubbling water on an exhaust panel having plural holes, and a smoke detector 30 that samples air, which has passed through the layer of bubbling water, and detects smoke on the basis of particulates contained in the air.SELECTED DRAWING: Figure 1

Description

  The present invention eliminates false alarms of fire occurrence and senses slight smoke generated at the early stage of fire with high accuracy in a bad environment such as cement plant, recycling plant and steel plant where dust and oil mist scatters a lot. To provide a fire alarm system that can

  In general, fire detection is performed by monitoring at least one of heat, smoke and flame generated by a fire source. Thermal sensors, smoke detectors, and flame detectors are conventionally known as means for automatically detecting heat, smoke and flames.

  The heat sensor detects the heat generated by the fire. Since heat generated by the fire is accumulated from the ceiling surface, this heat is sensed by a heat sensor attached to the ceiling surface. Thermal sensors are of the constant temperature type that operates when the ambient temperature exceeds a certain level, or of the differential type that operates when the rate of increase of the ambient temperature exceeds a certain level.

  Smoke detectors detect smoke produced by a fire. The smoke generated by the fire is accumulated from the ceiling surface, and this smoke is sensed by a smoke sensor attached to the ceiling surface. A smoke sensor transmits a signal if the ambient air contains smoke above a certain concentration. The smoke detector includes an ionization type spot type operated by a change of ion current by smoke, a photoelectric type spot type operated by a change of light reception amount of photoelectric element, and a change of light reception amount of photoelectric element by accumulation of a wide range of smoke. There is a photoelectric separation type that operates.

  The flame sensor detects the flame generated by the fire. For the flame sensor, an ultraviolet type that operates when the amount of ultraviolet light emitted from the flame exceeds a threshold, an infrared type that operates when the amount of infrared radiation emitted from the flame exceeds the threshold, or these ultraviolet type and infrared rays There is one that uses a formula together.

JP-A-2-173896 JP-A-7-044783

  In the process of a fire, smoke is generated from the fire source first, then the flame rises, and then the heat of the flame raises the ambient temperature. For this reason, it becomes possible to catch the early stage of a fire early by sensing the slight smoke which arose from the fire source. In this regard, smoke detectors are extremely effective means for early detection of fire and prevention of spread.

  However, conventional smoke detectors operate normally in an environment without disturbance such as general facilities, factories, houses, etc. However, for example, a large amount of dust and oil mist such as cement factories, recycling factories and steel mills There is a problem that it is not possible to operate normally in a scattering environment. That is, the conventional smoke detector can not distinguish between a large amount of dust and oil mist and smoke generated by a fire, and detects dust and oil mist to frequently generate a false alarm of fire occurrence. For this reason, the conventional smoke detector can not detect only a slight smoke generated while dust and oil mist scatter a lot. In particular, the higher the sensitivity of the smoke detector, the more frequently false alarms of fire occurrence occur, and it can not be used in an adverse environment where dust and oil mist scatter a lot.

  Also, the heat sensor has a problem that it can not detect a fire until the flame rises at the fire source and then the heat of the flame increases the ambient temperature. In a bad environment where dust and oil mist are scattered in a large amount, the flame of the fire source will ignite a large amount of dust and oil mist, so heat detection can not prevent the spread of the fire.

  Furthermore, the flame sensor is configured to detect a fire by causing at least one of ultraviolet light and infrared light emitted from the flame to be incident on the light receiving portion of the sensor. For this reason, in a bad environment where dust and oil mist are scattered in a large amount, the light receiving portion of the sensor is contaminated and can not operate normally.

  Here, JP-A-2-173896 (Patent Document 1) discloses a fire alarm device which cleans sampled air by a water filter device and cleans a sensing portion of a smoke detector by the cleaned air. It is done. However, the fire alarm device of Patent Document 1 is configured to generate fine bubbles in the water of the water filter device and remove all environmental noise factors including smoke. For this reason, it is not possible at all to sense the slight smoke generated at the early stage of the fire.

  Further, Japanese Patent Laid-Open No. 7-044783 (Patent Document 2) discloses a fire sensing device in which first and second filters made of porous materials such as sponge are disposed upstream of a smoke sensor. . However, the fire detection device of Patent Document 2 is premised on use in a clean room or computer room, and the first and second filters made of porous materials such as sponge are inferior in that dust and oil mist are scattered in large amounts. In the environment, it gets clogged quickly.

  The present invention has been made in view of the above problems, and in a bad environment such as a cement plant, a recycling plant and a steel plant where dust and oil mist are scattered in large amounts, false alarms of fire occurrence are eliminated and the early stage of fire It is an object of the present invention to provide a fire alarm system capable of detecting a slight amount of smoke generated in a high accuracy.

(1) In order to achieve the above object, the fire alarm device of the present invention is disposed at an inlet of a duct for exhausting, and forms a layer of bubbling water on an exhaust panel provided with a plurality of holes. And a smoke sensor for sampling air that has passed through the bubbling water layer and sensing smoke based on particles contained in the air.

(2) Preferably, in the fire alarm system according to (1), the water filter is
a) setting the exhaust air volume V (m ³ / min) of the duct,
b) configuring a plurality of holes provided in the exhaust panel;
The particles above 1 μm are removed by at least one of the above to form a layer of the bubbling water capable of passing fine particles of 1 μm or less.

(3) Preferably, in the fire alarm device of (2), the exhaust air volume V (m ³ / min) of the duct of the above a) is calculated by the following equation 1.
V (m ³ / min) = N * (W * D * H) ... 1
Where N is the wind velocity constant of air passing through the water filter, W is the width of the bubbling water layer formed on the exhaust panel, D is the depth of the bubbling water layer formed on the exhaust panel, H is the exhaust panel The opening ratio of the plurality of holes to the total area of

(4) Preferably, in the fire alarm device of the above (3), the value of the wind speed constant N in the formula 1 is set to 180 or more and 300 or less.

(5) Preferably, in the fire alarm system according to any one of the above (2) to (4), the a) the exhaust air flow rate V (m ³ / min) of the duct is 17 to 60 (m ³ / min) It is set within the range.

(6) Preferably, in the fire alarm device according to any one of the above (2) to (5), the exhaust panel of the above b) is a first panel provided with a plurality of first holes, and a plurality of second panels. The layer of bubbling water is thickened by including a second panel in which a hole is provided, and the first hole and the second hole overlap to constitute one hole.

(7) Preferably, in the fire alarm device according to any one of the above (2) to (5), peripheral portions of a plurality of holes provided in the exhaust panel of the b) are raised upward, The layer of bubbling water is made thicker by tapering the inner surface of each hole.

(8) Preferably, in the fire alarm device according to (6) or (7), the value of the aperture ratio H in the formula 1 is set to 0.4 or more and 0.8 or less.

(9) Preferably, in the fire alarm system according to any one of the above (1) to (8), the smoke detector measures the opacity (% / m) of the air, and is at least 0.2. It has the ability to measure opacity less than (% / m).

(10) Preferably, in the fire alarm device according to (9), the smoke detector includes a filter that removes particles of 20 μm or more from the air.

(11) Preferably, in the fire alarm system according to any one of the above (1) to (10), the control unit of the water filter is configured to set the air filter when the opacity (% / m) of the air exceeds a threshold. Control is performed to increase the amount of water supplied to form the bubbling water layer.

(12) Preferably, in the fire alarm system according to any one of the above (1) to (11), the control unit of the water filter is configured to control the temperature (° C.) of the air having passed through the exhaust panel exceeding a threshold. And performing control to stop an exhaust fan provided in the duct.

  According to the fire alarm device of the present invention, in a bad environment such as a cement plant, recycling plant and steel plant where dust and oil mist are scattered in a large amount, false alarms of fire occurrence are eliminated and slight smoke generated in the early stage of fire It becomes possible to sense with high accuracy.

FIG. 1 is a schematic view showing a fire alarm system according to an embodiment of the present invention. Fig.2 (a) is sectional drawing which shows the water filter which comprises the said fire alarm system. FIG.2 (b) is an enlarged view which shows the punching panel which comprises the said water filter. FIG. 3A is a perspective view showing the punching panel. FIG.3 (b) is a fragmentary sectional view which shows the structure of the hole of the said punching panel. FIG.3 (c) is a fragmentary sectional view which shows the structure of the other hole of the said punching panel. FIG. 4 is a schematic view showing a smoke sensor which constitutes the fire alarm device. FIG. 5 is a schematic view showing the fire alarm device installed on a cement conveyor of a cement plant. FIG. 6 is a flowchart showing control processing of the smoke sensor. FIG. 7 is a flowchart showing control processing of the water filter. FIG. 8 is a graph showing the relationship between the particle size (μm) and the frequency (%) of dust collected near the ceiling in a factory where a cement conveyor is installed.

  Hereinafter, a fire alarm device according to an embodiment of the present invention will be described with reference to the drawings.

<Configuration of entire device>
As shown in FIG. 1, the fire alarm system 1 of the present embodiment comprises at least a water filter 10 and a smoke sensor 30, and for example, a large amount of dust and oil mist such as a cement plant, a recycling plant and a steel plant. It is installed in a bad environment that scatters. Further, the fire alarm device 1 includes a hood 2 which is an exhaust system, a duct 3 and an exhaust fan 4. The hood 2, the duct 3 and the exhaust fan 4 may be used as they are already installed in a building or facility to be subjected to fire monitoring, or may be newly installed together with the water filter 10 and the smoke sensor 30. Good.

The water filter 10 and the sampling pipe 31 of the smoke sensor 30 are disposed at the inlet 3 a of the duct 3. In the middle of the duct 3, an exhaust fan 4 is attached. The exhaust fan 4 receives power and operates to generate an exhaust air volume V (m ³ / min) of the duct 3 to the water filter 10. By operating the exhaust fan 4, ambient air including a large amount of dust and oil mist is sucked into the water filter 10, passes through the duct 3 and is discharged to the outside.

  The water filter 10 removes dust and oil mist (average particle diameter 20 μm or more) contained in the sucked air, and passes smoke particles (average particle diameter 0.3 μm to 1 μm). The smoke sensor 30 samples air that has passed through the water filter 10 through the sampling pipe 31 and senses smoke contained in the air.

  The fire alarm device 1 of the present embodiment may be configured to install a plurality of ducts 3 and water filters 10 corresponding to a single exhaust fan 4.

<Structure of water filter>
As shown in FIG. 2A, the water filter 10 includes a main body 10A and a water tank 10B. The main body portion 10A and the water tank portion 10B are each formed of a bent metal plate. Although not shown, the main body 10A and the water tank 10B extend long in the depth direction of the drawing. The water tank portion 10B is provided with two air intake ports 11 for suctioning ambient air. Each of these intake ports 11 extends long in the depth direction of the drawing.

  In the description of the present specification, the width in the left-right direction of the water filter 10 shown in FIG. 1 and FIG. 2A is called “width” and is not shown in FIG. 1 and FIG. The width in the depth direction of the water filter 10 is called "depth". However, the “width” and “depth” of the water filter 10 are merely descriptive names, and the width in the lateral direction of the water filter 10 shown in FIGS. 1 and 2A is called “depth”, The width in the depth direction of the water filter 10 not shown in FIGS. 1 and 2A may be referred to as “width”. The same applies to the “width” and “depth” of the punching panel 12 and the layer of the bubbling water BW.

  The boundary between the main body 10A and the water tank 10B is partitioned by a punching panel (exhaust panel) 12. As shown in FIGS. 2 (b) and 3 (a), the punching panel 12 is provided with a large number of holes 12a for passing air. As shown in FIG. 2A, a plurality of nozzles 13 and a plurality of drainage filters 14 are provided in the main body 10A. The nozzle 13 is disposed above the punching panel 12. The drainage filter 14 is disposed above the nozzle 13. The drainage filter 14 is formed of a metal mesh.

The nozzle 13 is connected to a water supply pipe 18 shown in FIGS. 1 and 2 (a). A motor-operated valve 17 is provided in the middle of the water supply pipe 18. Water is supplied to the nozzle 13 by opening the motor-operated valve 17. The motor operated valve 17 opens and closes based on a command from the control board 16. The user of the fire alarm system 1 can operate the control panel 16 to select either the normal operation or the cleaning operation. When the user selects normal operation, the control panel 16 opens the solenoid valve 17 during operation of the exhaust fan 4 to supply a fixed amount of water to the nozzle 13. The water jetted from the nozzle 13 is accumulated on the punching panel 12 and is sucked by the exhaust air volume V (m ³ / min). Thereby, a layer of bubbling water BW shown in FIGS. 2A and 2B is formed on the punching panel 12. On the other hand, when the user selects the cleaning operation, the control panel 16 sprays water from the nozzle 13 for a certain period of time to clean the inside of the main body 10A and the water tank 10B.

  Furthermore, the user of the fire alarm device 1 can operate the control panel 16 to select the fire suppression operation. As shown in FIG. 1, a temperature sensor 15 is disposed in the main body 10 </ b> A of the water filter 10. The temperature sensor 15 is electrically connected to the control board 16. When the user selects the fire suppression operation, the control panel 16 monitors the temperature near the inlet 3 a of the duct 3 based on the detection result of the temperature sensor 15. When the temperature sensor 15 detects an abnormally high temperature, the control panel 16 reports a fire by means of a lamp and a buzzer. Further, the control panel 16 jets water from the nozzles 13 for a certain period of time to suppress a fire in the duct 3. Furthermore, the control board 16 is electrically connected to the alarm display board 37 of the smoke sensor 30. When the temperature sensor 15 detects an abnormally high temperature, the control panel 16 transmits a notification signal to the alarm display panel 37 to display information on fire on a display or the like.

  The control panel 16 may be configured to transmit a notification signal to a control panel of an automatic fire extinguishing device (not shown). The automatic fire extinguishing device is installed, for example, in a building or facility to be subjected to fire monitoring, and the fire extinguishing device that receives the transfer signal from the control panel 16 injects the extinguishing agent when the fire occurs here It is deterred by

  As shown to FIG. 1 and FIG. 2 (a), the water tank part 10B of the water filter 10 is connected to the drainage pipe 19. As shown in FIG. The water jetted from the nozzle 13 flows through the holes 12 a of the punching panel 12 into the water tank portion 10 B. The water flowing into the water tank portion 10B is drained to the outside through the drain pipe 19.

<Formation of a layer of bubbling water>
The particle removal performance of the water filter 10 is determined by the thickness T of the layer of bubbling water BW shown in FIG. 2 (b). That is, by controlling the thickness T of the layer of bubbling water BW, the size of the particles to be removed by the water filter 10 and the size of the particles passing through the water filter 10 are determined. For example, the average particle size of the smoke particulates is in the range of about 0.3 μm to 1 μm. On the other hand, the average particle size of dust and oil mist particles is much more than 1 μm (20 μm or more).

Therefore, particles of more than 1 μm are removed by at least one of the following a) and b) to form a bubbling water BW layer having a thickness T capable of passing fine particles of 1 μm or less.
a) setting the exhaust air volume V (m ³ / min) of the duct 3 b) constructing a large number of holes 12 a provided in the punching panel 12

The exhaust air volume V (m ³ / min) of the duct 3 of the above a) is calculated by the following equation 1.
V (m ³ / min) = N * (W * D * H) ... 1
Where N is the wind velocity constant of air passing through the water filter, W is the width of the layer of bubbling water BW formed on the exhaust panel, D is the depth of the layer of bubbling water BW formed on the exhaust panel, H is The opening ratio of the plurality of holes 12 a to the total area of the punching panel 12.

  The width W of the layer of bubbling water BW can be, for example, 250 mm. The depth D of the layer of bubbling water BW can be, for example, 600 mm, 750 mm, 900 mm, 1050 mm, 1200 mm or 1500 mm. As described above, the width W and the depth D are merely convenient names, and the values of the width W and the depth D may be reversed. The aperture ratio H of the plurality of holes 12a is, for example, 0.4 or more and 0.8 or less, preferably 0.6.

The wind speed constant N in the above equation 1 affects the thickness T of the layer of bubbling water BW. The wind velocity constant N is preferably 180 or more and 300 or less. By setting the wind speed constant N to 180 or more and 300 or less, the thickness T of the layer of bubbling water BW becomes large, and it becomes possible to remove dust and oil mist. If the wind speed constant N is less than 180, the exhaust air volume V (m ³ / min) becomes too small, and the thickness T of the layer of bubbling water BW capable of removing dust and oil mist can not be obtained . On the other hand, when the wind speed constant N is more than 300, the exhaust air volume V (m ³ / min) becomes too large, and the layer of the bubbling water BW is not formed on the punching panel 12.

The exhaust air volume V (m ³ / min) of the duct 3 in the above a) also affects the thickness T of the layer of bubbling water BW. The exhaust air flow rate V (m ³ / min) of the duct 3 is preferably in the range of 17 to 60 (m ³ / min). More preferably, the exhaust air flow rate V (m ³ / min) of the duct 3 may be 17.6 to 24.3 (m ³ / min).

However, in the case where the thickness T of the bubbling water BW is increased only by the exhaust air volume V (m ³ / min) of the duct 3 in the above a), it is necessary to increase the facilities such as the water filter 10 and the exhaust fan 4 There is. Therefore, it is preferable to increase the thickness T of the layer of bubbling water BW while suppressing the exhaust air flow rate V (m ³ / min) of the duct 3 to a small value.

  Therefore, it is preferable to use the method b) in combination with the method a). That is, the thickness T of the layer of the bubbling water BW can be increased by changing the holes 12 a of the punching panel 12 from simple punching holes to special configurations.

  For example, the punching panel 12 shown in FIG. 3B has a configuration in which a plurality of panels 21, 22. The first panel 21 is provided with a first hole 21 a. The second panel 22 is provided with a second hole 22 a. The first hole 21a and the second hole 22a have the same diameter, but their center positions are slightly shifted. The first hole 21a and the second hole 22a partially overlap each other to constitute a single hole 12a shown in FIG. 3 (a). The hole 12a has a depth d which is the sum of the first and second holes 21a and 22a. The depth d of the holes 12a increases as the number of panels 21, 22. Preferably, the depth d of the holes 12a is larger than the diameters of the first and second holes 21a, 22a.

  By increasing the depth d of the holes 12a, the resistance when water on the punching panel 12 passes through the holes 12a is increased. This reduces the amount of water passing through the holes 12a. As a result, water tends to be accumulated on the punching panel 12, and the thickness T of the layer of bubbling water BW becomes large. Moreover, since the single hole 12a is comprised in the state which the 1st hole 21a and the 2nd hole 22a shifted, resistance when water passes the hole 12a increases more. As a result, the thickness T of the layer of bubbling water BW is further increased. It is possible to adjust the thickness T of the layer of the bubbling water BW by increasing or decreasing the number of panels 21, 22... For constituting the punching panel 12.

  On the other hand, as shown in FIG. 3C, the peripheral portion of the hole 12a of the punching panel 12 may be raised upward to make the inner surface of the hole 12a tapered. This configuration increases the depth d of the holes 12a. Furthermore, the tapered hole 12a has a large inlet diameter and a small outlet diameter. Since the exhaust of the cooking appliance 5 enters from the large diameter inlet and exits from the small diameter outlet, the exhaust resistance of the punching panel 12 is reduced. As a result, the thickness T of the layer of bubbling water BW becomes large.

According to the above b), when the holes 12a of the punching panel 12 have the special configuration shown in FIGS. 3 (b) and 3 (c), the thickness T of the layer of the bubbling water BW becomes large. This makes it possible to reduce the value of the wind speed constant N used for the calculation of the exhaust air volume V (m ³ / min) of the duct 3 described in a).

  By using both of the above a) and b), the value of the wind velocity constant N in the above equation 1 can be made smaller. That is, it is possible to increase the thickness T of the layer of bubbling water BW without increasing the equipment such as the water filter 10 and the exhaust fan 4.

<Composition of smoke detector>
As shown in FIG. 1, the smoke sensor 30 samples air that has passed through the water filter 10 to sense smoke particles contained in the air. The configuration of the smoke sensor 30 is shown in FIG. In FIG. 4, the smoke sensor 30 includes a sampling pipe 31, a suction device 32, a first filter 33, a second filter 34, a laser chamber 35, a control unit 36 and an alarm display board 37.

  As mentioned above, one end of the sampling tube 31 is disposed at the inlet 3a of the duct 3 shown in FIG. The other end of the sampling pipe 31 is connected to the suction port of the suction device 32 shown in FIG. The suction device 32 includes a suction fan 32 a for suctioning air. The exhaust port of the suction device 32 is connected to the inlet of the first filter 33.

  The first filter 33 has a function of removing particles of 20 μm or more contained in the air. The first filter 33 has first and second outlets. The first outlet of the first filter 33 is connected to the second section 35 B of the laser chamber 35. On the other hand, the second outlet of the first filter 33 is connected to the inlet of the second filter 34.

  The second filter 34 has a function of removing particulates of 0.3 μm or more contained in the air. The outlet of the second filter 34 is connected to the first section 35A and the third section 35C of the laser chamber 35 via a branch line.

  The inside of the laser chamber 35 is divided into first to third sections 35A to 35C. The laser emission unit 35a is disposed in the first section 35A. The laser light emitting unit 35a is, for example, a laser diode and emits a laser beam. In the second section 35B, a plurality of photodetectors 35b are installed. The photodetector 35 b detects the laser light scattered by the particles flowing into the second section 35 B. Each light detector 35 b outputs a signal according to the light amount of the received laser beam. The control unit 36 receives the signal output from each of the light detectors 35 b and measures the opacity (% / m) of air. If the measurement result exceeds the threshold value, the control unit 36 transmits a mobile alert signal for reporting the occurrence of a fire. Here, the light detector 35 b and the control unit 36 of the present embodiment have a capability of measuring the opacity of at least 0.2 (% / m) or less. The alarm display panel 37 receives a mobile alert signal from the control unit 36, and displays information on the occurrence of a fire on a display or the like.

  A laser receiving unit 35c is installed in the third section 35C. The laser light receiving unit 35c absorbs the laser light emitted from the laser light emitting unit 35a. The first to third sections 35A to 35C are capable of circulating air, and the air flowing into the first to third sections 35A to 35C is outside the smoke sensor 30 from the exhaust port 38 of the laser chamber 35. Exhausted to

  The smoke sensor 30 of the present embodiment is configured to be able to connect a plurality of sampling tubes 31 to the suction device 32. According to this configuration, a plurality of ducts 3 and water filters 10 may be installed corresponding to a single smoke sensor 30 (see FIG. 5).

<Operation of smoke detector>
In FIG. 1, the air that has passed through the water filter 10 is drawn into the suction device 32 shown in FIG. 4 via the sampling pipe 31 and sampled. The sampled air passes through the first filter 33. The first filter 33 removes particles of 20 μm or more contained in the sampled air. That is, even if dust or oil mist remains in the air that has passed through the water filter 10, it is removed by the first filter 33. As a result, in the sampled air, fine particles smaller than dust and oil mist remain.

  Part of the air that has passed through the first filter 33 flows into the second section 35B of the laser chamber 35 from the first outlet. When fine particles of smoke of 1 μm or less are contained in the air, laser light emitted from the laser light emitting unit 35 a is scattered and detected by the respective light detectors 35 b. The control unit 36 measures the opacity (% / m) of air based on the detection results of the respective light detectors 35b. If the measurement result exceeds the threshold value, the control unit 36 transmits a mobile alert signal for reporting the occurrence of a fire. The alarm display panel 37 receives a mobile alert signal from the control unit 36, and displays information on the occurrence of a fire on a display or the like.

  On the other hand, the other part of the air which has passed through the first filter 33 flows into the second filter 34 from the second outlet. The second filter 34 further removes particulates of 0.3 μm or more from the air that has passed through the first filter 33. The air that has passed through the second filter 34 contains not only dust and oil mist but also particulates such as smoke.

  Such clean air flows from the outlet of the second filter 34 into the first section 35A and the third section 35C of the laser chamber 35 through the branch line. The clean air that has flowed into the first section 35A cleans an optical system such as a lens that constitutes the laser light emitting unit 35a. On the other hand, the clean air that has flowed into the third section 35C cleans the components of the laser light receiving unit 35c.

<Installation Example of Fire Alarm Device>
FIG. 5 shows a state in which the fire alarm device 1 of the present embodiment is installed on the cement conveyor 5 of a cement plant. The cement conveyor 5 is for conveying the finely ground cement raw material to the next step in the grinding process of cement production. The cement conveyor 5 is covered by a cover 5a, and the inside of the cover 5a presents an adverse environment in which a large amount of dust scatters. In such a bad environment, dust may be ignited only by the generation of a small flame, and the fire may spread in an instant. The fire alarm device 1 of the present embodiment monitors the generation of a slight smoke generated in the early stage of the fire in the cover 5a.

  As shown in FIG. 5, ducts 3 for sampling air are provided at two upstream and downstream positions of the cover 5 a of the cement conveyor 5. The inlet of each duct 3 communicates with the space in the cover 5a. At the inlet side of each duct 3 a water filter 10 and a sampling tube 31 of the smoke detector 30 are arranged. An exhaust fan 4 shown in FIG. 1 is provided on the outlet side of each duct 3.

  Each water filter 10 is electrically connected to a common control panel 16. The control board 16 controls the supply of water to each water filter 10 and monitors the temperature near the inlet of each duct 3. Also, monitoring of smoke upstream and downstream of the cover 5a is performed by a common smoke sensor 30. The smoke sensor 30 samples air passing through each water filter 10 through the two sampling tubes 31 and senses smoke contained in the air. The smoke detector 30 is electrically connected to the alarm display panel 37 and the control panel 16 common to the water filters 10. The control panel 16 is electrically connected to the alarm display panel 37. The control process of the smoke sensor 30 and the water filter 10 will be described next.

<Control processing of smoke detector>
The control process of the smoke sensor 30 will be described with reference to the flowchart of FIG. The control process of the flowchart shown in FIG. 6 is executed by the control unit 36 of the smoke sensor 30.

  When the smoke sensor 30 is activated, the control unit 36 drives the suction device 32 in step S1. Thus, air that has passed through the water filter 10 is sampled through the sampling pipe 31. A part of the sampled air passes through the first filter 33 of FIG. 4 and flows into the second section 35B of the laser chamber 35, and the detection of smoke by each light detector 35b is performed. In addition, another part of the sampled air passes through the first and second filters 33 and 34 in FIG. 4 and flows into the first section 35A and the third section 35C of the laser chamber 35, and the laser emitting unit The components of the optical system 35a and the laser receiving unit 35c are cleaned.

  Next, the process proceeds to step S2, and the control unit 36 measures the opacity (% / m) of air based on the detection results of the respective light detectors 35b. Then, the control unit 36 determines whether the opacity of air is 0.1 (% / m) or more. If it is determined that the opacity of air is not 0.1 (% / m) or more (NO), the control unit 36 acquires a new detection result from each of the light detectors 35b, and repeats the determination in step S2.

  On the other hand, when it is determined in step S2 that the opacity of air is 0.1 (% / m) or more (YES), the process proceeds to step S3, and the control unit 36 transmits a transfer alert signal. This notification signal is transmitted based on the detection of a slight smoke generated in the early stage of the fire, and indicates that there is a risk of fire (prediction of fire occurrence). Therefore, the transfer signal in step S3 is hereinafter referred to as "preliminary transfer signal". The preliminary announcement signal is received by the alarm display panel 37 and the control panel 16 of the water filter 10. The alarm display panel 37 that has received the advance announcement signal displays on a display or the like that there is a risk of fire occurrence (prediction of fire occurrence). In addition, the control panel 16 of the water filter 10 that has received the advance announcement signal executes the process of step 14 of FIG. 7 described later.

  Next, the process proceeds to step S4, and the control unit 36 measures the opacity (% / m) of air based on the detection result of each light detector 35b. Then, the control unit 36 determines whether the opacity of air exceeds 2 (% / m). If it is determined that the opacity of air does not exceed 2 (% / m) (NO), the control unit 36 acquires a new detection result from each of the light detectors 35b, and repeats the determination in step S4.

  On the other hand, when it is determined in step S4 that the opacity of air exceeds 2 (% / m) (YES), the process proceeds to step S5, and the control unit 36 transmits a mobile alert signal. The mobile notification signal is transmitted based on the detection of the amount of smoke generated by the fire occurrence, and indicates that the fire has actually occurred (determination of the fire occurrence). Therefore, the movement report signal in step S5 is hereinafter referred to as "fire detection signal." The fire alarm signal is received by the alarm display panel 37 and the control panel 16 of the water filter 10. The alarm display panel 37 which has received the fire notification signal displays on a display or the like that the fire has actually occurred (confirmation of the occurrence of the fire). Moreover, the control panel 16 of the water filter 10 which received the fire alerting signal performs the process of FIG.7 S17 mentioned later.

<Control processing of water filter>
The control process of the water filter 10 will be described with reference to the flowchart of FIG. The control process of the flowchart shown in FIG. 7 is executed by the control panel 16 of the water filter 10.

When the control board 16 is activated, the control board 16 drives the exhaust fan 4 in step S11. Next, in step S12, the control panel 16 opens the motor-operated valve 17 at a predetermined opening degree. As a result, a predetermined amount of water (for example, 3 to 4 L / h) is supplied per unit time to the nozzle 13 of the water filter 10 shown in FIG. 2 (a). The water jetted from the nozzle 13 is accumulated on the punching panel 12 and is sucked by the exhaust air volume V (m ³ / min). As a result, a layer of bubbling water BW having a predetermined thickness T shown in FIGS. 2A and 2B is formed on the punching panel 12. The layer of bubbling water BW removes particles exceeding 1 μm contained in the air sucked into the duct 3, that is, dust and oil mist. In addition, the layer of bubbling water BW passes smoke particles of 1 μm or less contained in the air sucked into the duct 3. The particulate matter of the smoke which has passed through the layer of bubbling water BW is detected by each light detector 35b of the above-described smoke detector 30 (step S2, step S4 in FIG. 6).

  Next, the process proceeds to step S13, where the control panel 16 determines whether or not the notice transfer notification signal has been received from the smoke detector 30. The notice transfer notification signal indicates that there is a risk of fire occurrence (prediction of a fire occurrence), and is transmitted in step S3 of FIG. If it is determined that the preliminary announcement transfer signal has not been received (NO), the control board 16 repeats the determination of step S13.

  On the other hand, if it is determined in step S13 that the notice transfer notification signal has been received (YES), the process proceeds to step S14, and the control panel 16 fully opens the motor operated valve 17. As a result, the amount of water supplied to the nozzle 13 is maximized, and the nozzle 13 jets the maximum amount of water. As a result, even when a fire actually occurs, flames and fire powder are suppressed at the inlet 3 a of the duct 3, and the spread of the fire inside the duct 3 and outside the duct 3 is prevented.

  Next, the process proceeds to step S15, where the control panel 16 determines whether a fire transfer notification signal has been received from the smoke detector 30 or not. The fire notification signal notifies that the fire has actually occurred (confirmation of the fire occurrence), and is transmitted in step S5 of FIG. If it is determined that the fire alarm signal has not been received (NO), the control board 16 repeats the determination of step S15.

  On the other hand, if it is determined in step S15 that the fire alarm signal has been received (YES), the process proceeds to step S16, and the control board 16 controls the inlet 3a of the duct 3 based on the detection result of the temperature sensor 15 shown in FIG. It is determined whether the temperature in the vicinity is 100 ° C. or more. If it is determined that the temperature is not higher than 100 ° C. (NO), the control board 16 repeats the determination of step S16.

  On the other hand, when it is determined in step S16 that the temperature in the vicinity of the inlet 3a of the duct 3 is 100 ° C. or higher (YES), the process proceeds to step S17, and the control panel 16 stops the exhaust fan 4 shown in FIG. As a result, the high temperature air generated by the fire is not exhausted from the outlet of the duct 3 to the outside, and the spread of the fire is prevented.

  Thereafter, the process proceeds to step S18, where the control board 16 transmits a mobile report signal. The notification signal of step S18 is transmitted, for example, to the control panel of the automatic fire extinguishing system (not shown) and the alarm display panel 37 of the smoke detector 30. The automatic fire extinguishing device having received the transfer notification signal of step S18 sprays a fire extinguishing agent to a building or facility to be subjected to fire monitoring. As a result, the fire of a building or equipment to be subjected to fire monitoring and the spread of the fire outside the duct 3 are prevented. In addition, the alarm display panel 37 that has received the transfer alert signal of step S18 displays information on fire on a display or the like.

<Function effect>
As described above, according to the fire alarm device 1 of the present embodiment, false reports of fire occurrence are eliminated in a bad environment such as a cement plant, a recycling plant and a steel plant where dust and oil mist are scattered in large amounts, It becomes possible to sense the slight smoke generated in the stage with high accuracy.

  That is, by the layer of bubbling water BW formed by the water filter 30, it becomes possible to remove dust and oil mist from the sampled air and to pass only smoke particles. As a result, the false alarm of the smoke detector 30 disappears, and a highly sensitive smoke detector capable of measuring the opacity of 0.2 (% / m) or less in a bad environment where dust and oil mist scatter a lot 30 can be used. As a result, in an adverse environment where a large amount of dust and oil mist scatters, it is possible to sense the slight smoke generated at the early stage of the fire with high accuracy.

  In addition, the control process of the water filter 30 shown in FIG. 7 can prevent the fires of buildings and facilities to be monitored for fires and the spread of fires out of the duct 3, resulting in a large amount of dust and oil mist. It is possible to minimize the damage caused by a fire that occurs in a scattering environment.

  The following water filter, smoke detector and exhaust fan were installed in the duct to constitute the fire alarm system shown in FIG.

<Configuration of fire alarm device>
The overall configuration of the water filter is the same as in FIG. 2 (a). In this example, an exhaust panel having a configuration shown in FIG. 3B was manufactured using two punching panels. The plate thickness of the punching panel is 2 mm, and a plurality of holes with a diameter of 6 mm are uniformly provided. The two punched panels were stacked so that the center positions of the holes were slightly offset from each other, to obtain an exhaust panel with an opening ratio H of a plurality of holes to the total area of 0.6.

The exhaust fan had a wind speed constant N = 233 and an exhaust air volume V = 21 (m ³ / min) or more. When the exhaust fan is operated and water of 3 to 4 L / h is quantitatively supplied to the exhaust panel, a layer of bubbling water of width W = 250 mm and depth D = 600 mm is formed on the exhaust panel.

  As a smoke sensor, an ultra-sensitive smoke sensor capable of detecting the opacity of sampled air at 0.1 (% / m) or more was used. The ultra-high sensitivity smoke sensor of this embodiment is equipped with a filter for removing particles of 20 μm or more contained in sampled air, and particles with a particle size of less than 20 μm are to be detected. As in FIG. 1, one end of the sampling tube of the ultra-sensitive smoke detector was placed above the water filter at the inlet of the duct.

<Particle size distribution of collected dust>
Dust was collected near the ceiling in the factory where the cement conveyor shown in FIG. 5 was installed. The relationship between the particle size (μm) and the frequency (%) of the collected dust is shown in the graph of FIG. The average particle size of the dust near the ceiling was 22.43 (μm).

<Test method>
The collected dust and the smoke from the incense stick for the smoke sensor test were individually sucked into the water filter of the example, and it was tested whether the ultra-sensitive smoke detector could detect only the smoke. The collected dust was diffused by the wind of the drier and was sucked into the inlet of the water filter. On the other hand, an incense stick for smoke sensor test was prepared near the inlet of the water filter, and the smoke was sucked into the inlet of the water filter. First, with the water filter turned off, dust only and smoke only were sampled by the ultra-high sensitivity smoke detector to detect air opacity (% / m). Next, with the water filter turned on, dust only and smoke only were sampled by the ultra-sensitive smoke detector to detect air opacity (% / m).

<Test result>
The test results of this example are shown in Table 1 below. With regard to dust, the opacity when the water filter is turned off is 0.345 (% / m), and the opacity when the water filter is turned on is 0.082 (% / m). According to these test results, it can be understood that most of the dust is removed from the air that has passed through the water filter, and the false alarm of the ultra-sensitive smoke detector due to the dust does not occur.

  On the other hand, in Table 1 below, with regard to smoke, the opacity when the water filter is turned off is 0.125 (% / m) and the opacity when the water filter is turned on is 0.176 (%) / M). According to these test results, it can be understood that the water filter can pass fine particles of smoke contained in the air and can be sensed by the ultrasensitive smoke sensor.

  As the above test results show, according to the fire alarm device of the present invention, false alarms of fire occurrence are eliminated in a bad environment such as cement plant, recycling plant and steel plant where dust and oil mist are scattered in a large amount. It is possible to sense the slight smoke generated in the early stage of

1 Fire alarm system 1
10 Water filter 10A Main body 10B Water tank 11 Air intake 12 Punching panel (Exhaust panel)
12a hole 13 nozzle 14 drainage filter 15 temperature sensor 16 control panel 17 motor operated valve 18 water supply pipe 19 drain pipe 21 first panel 21a first hole 22 second panel 22a second hole 30 smoke detector 31 sampling tube 32 suction device 32a suction Fan 33 first filter 34 second filter 35 laser chamber 35A to 35C first to third sections 35a laser light emitting unit 35b light detector 35c laser light receiving unit 36 control unit 37 alarm display panel 38 exhaust port 2 hood 3 duct 3a inlet 4 exhaust fan 5 cement conveyor 5a cover BW bubbling water T bubbling water layer thickness

Claims (12)

A water filter arranged at the inlet of the duct for exhausting and configured to form a layer of bubbling water on an exhaust panel provided with a plurality of holes;
A fire alarm system comprising: a smoke sensor sampling air which has passed through the bubbling water layer and sensing smoke based on particles contained in the air. The water filter is
a) setting the exhaust air volume V (m ³ / min) of the duct,
b) configuring a plurality of holes provided in the exhaust panel;
The fire alarm device according to claim 1, wherein particles of more than 1 μm are removed by at least one of the above to form a layer of the bubbling water capable of passing fine particles of 1 μm or less. The fire alarm system according to claim 2, wherein the exhaust air flow rate V (m ³ / min) of the duct of the above a) is calculated by the following equation 1.
V (m ³ / min) = N * (W * D * H) ... 1
Where N is the wind velocity constant of air passing through the water filter, W is the width of the bubbling water layer formed on the exhaust panel, D is the depth of the bubbling water layer formed on the exhaust panel, H is the exhaust panel The opening ratio of the plurality of holes to the total area of   The fire alarm device according to claim 3, wherein the value of the wind speed constant N in the formula 1 is 180 or more and 300 or less. The fire alarm device according to claim 2, wherein: a) the exhaust air flow rate V (m ³ / min) of the duct is set within a range of 17 to 60 (m ³ / min).   The exhaust panel of b) includes a first panel provided with a plurality of first holes, and a second panel provided with a plurality of second holes, and the first hole and the second hole The fire alarm device according to any one of claims 2 to 5, wherein the bubbling water layer is thickened by forming one hole in an overlapping manner.   The layer of the bubbling water is thickened by raising the peripheral portions of the plurality of holes provided in the exhaust panel of the above b) upward to make the inner surface of each hole tapered. The fire alarm device according to any one of 2 to 5.   The fire alarm device according to claim 6 or 7, wherein the value of the aperture ratio H in the formula 1 is 0.4 or more and 0.8 or less.   The smoke sensor is configured to measure the opacity (% / m) of the air, and has a performance capable of measuring the opacity of at least 0.2 (% / m) or less. The fire alarm device according to any one of to 8.   10. The fire alarm device according to claim 9, wherein the smoke detector comprises a filter that removes particles of 20 [mu] m or more from the air.   The control unit of the water filter executes control to increase the supply amount of water for forming the bubbling water layer, when the opacity (% / m) of the air exceeds a threshold. The fire alarm device according to any one of 1 to 10.   The control unit of the water filter executes control to stop the exhaust fan provided in the duct when the temperature (° C.) of the air passing through the exhaust panel exceeds a threshold value. The fire alarm device according to any one of the items.