EP1975896A2 - Smoke detector and sampling air supplying method for smoke detector - Google Patents
Smoke detector and sampling air supplying method for smoke detector Download PDFInfo
- Publication number
- EP1975896A2 EP1975896A2 EP08251196A EP08251196A EP1975896A2 EP 1975896 A2 EP1975896 A2 EP 1975896A2 EP 08251196 A EP08251196 A EP 08251196A EP 08251196 A EP08251196 A EP 08251196A EP 1975896 A2 EP1975896 A2 EP 1975896A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- pipe
- flow path
- fan
- smoke detection
- gas flow
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B17/00—Fire alarms; Alarms responsive to explosion
- G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B17/00—Fire alarms; Alarms responsive to explosion
- G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
- G08B17/11—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using an ionisation chamber for detecting smoke or gas
- G08B17/113—Constructional details
Definitions
- the present invention relates to a smoke detector for optically detecting contaminants such as smoke floating in the air, and a sampling air supplying method therefor.
- a smoke detector is used for preventing fire or as a detecting system at a time of occurrence of fire or in a semiconductor manufacturing plant or a food industry requiring a certain level of environmental conservation.
- the smoke detector there is used a high-sensitive smoke detecting apparatus.
- the high-sensitive smoke detecting apparatus air is sucked from a warning area through a sampling pipe by driving a fan, light receiving signals are converted into pulse signals through a comparison between the light receiving signals and a threshold value using a comparator, the light receiving signals being obtained by irradiation of light whose beam spots are focused on smoke particles contained in the sucked air, and the number of the pulse signals are counted, thereby measuring a smoke amount (see Japanese Patent No. 3312712 ).
- a primary side (suction port side of fan) at which a fluid (sampling air) has not been applied with energy by a fan and a secondary side (exhaust port side) at which the fluid has been applied with energy are connected through a smoke detection portion of a black box, and by using a pressure difference between the primary side and the secondary side, the sampling air is supplied to the smoke detection portion.
- a sampling flow rate changes in some cases.
- the sampling flow rate changes due to P-Q characteristics of the fan, fluctuation is caused in the pressure difference between the primary side and the secondary side, and the sampling air cannot be supplied to the smoke detection portion at a preset flow velocity. Therefore, accurate smoke detection becomes difficult.
- the present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to enable supply of a sampling air to a smoke detection portion at a stable flow velocity.
- the present invention relates to a smoke detector including: a smoke detection portion having an inflow port and an outflow port; a sampling pipe laid in a monitor space; a gas flow pipe which is connected to the sampling pipe and which houses a fan therein; a flow path branching portion provided to the gas flow pipe on a secondary side of the fan and connected to the inflow port of the smoke detection portion; and a flow path merging portion which is provided to the gas flow pipe on the secondary side of the fan and connected to the outflow port of the smoke detection portion, and at which a pressure of a fluid flowing through the gas flow pipe is lower than a fluid flowing through the gas flow pipe at the flow path branching portion.
- the present invention relates to a smoke detector including: a smoke detection portion having an inflow port and an outflow port; a sampling pipe laid in a monitor space; a fan for connecting the sampling pipe to a suction port; a divergent pipe which has a substantially pyramidal shape connected to an exhaust port of the fan and which is wider downstream; a flow path branching portion provided downstream of the divergent pipe, for supplying a sampling air from the divergent pipe to the smoke detection portion; and a flow path merging portion provided upstream of the flow path branching portion, for performing exhaustion from the smoke detection portion to the divergent pipe.
- the present invention relates to a smoke detector including: a smoke detection portion having an inflow port and an outflow port; a sampling pipe laid in a monitor space; a gas flow pipe which is connected to the sampling pipe and which houses a fan therein; a flow path branching portion provided to the gas flow pipe on a secondary side of the fan and connected to the inflow port of the smoke detection portion; and a flow path merging portion which is provided on the secondary side of the fan and in the vicinity thereof and connected to an outflow port of the smoke detection portion, and at which a pressure of a fluid flowing through the gas flow pipe is lower than a fluid flowing through the gas flow pipe at the flow path branching portion.
- the present invention relates to a sampling air supplying method for a smoke detector, the smoke detector including: a smoke detection portion having an inflow port and an outflow port; a sampling pipe laid in a monitor space; a gas flow pipe which is connected to the sampling pipe and which houses a fan therein; a flow path branching portion provided to the gas flow pipe on a secondary side of the fan and connected to the inflow port of the smoke detection portion; and a flow path merging portion which is provided on the secondary side of the fan and in the vicinity thereof and connected to an outflow port of the smoke detection portion, and at which a pressure of a fluid flowing through the gas flow pipe is lower than a fluid flowing through the gas flow pipe at the flow path branching portion, the sampling air supplying method including introducing a part of the fluid from the flow path branching portion to the smoke detection portion owing to a pressure difference in the fluid on the secondary side of the fan.
- the present invention is structured as described above. Accordingly, owing to the pressure difference in the fluid between the flow path branching portion and the flow path merging portion, a part of the sampling air flowing through the gas flow pipe is introduced from the flow path branching portion into the smoke detection portion, is allowed to pass through the smoke detection portion, and is returned into the gas flow pipe from the flow path merging portion. Therefore, the sampling air can be supplied to the smoke detection portion at a constant flow velocity, so accurate smoke detection can be performed.
- FIGS. 1 and 2 A first embodiment of the present invention will be described with reference to FIGS. 1 and 2 .
- a smoke detector 1 includes a smoke detection unit 2 provided with a black box 21, a fan 3 for sending an air (sampling air) SA to be sensed by the smoke detection unit 2, a piping 4 constituting an air passage, a light emitting element 11 disposed in the smoke detection unit 2, a light receiving element 12 such as a photodiode, an air flow sensor 13 for measuring a flow rate of the fan 3 or air, a power source portion 14 for supplying power to the air flow sensor 13, and a fire determination portion 15 connected to a light receiving element 12.
- a smoke detection unit 2 provided with a black box 21, a fan 3 for sending an air (sampling air) SA to be sensed by the smoke detection unit 2, a piping 4 constituting an air passage, a light emitting element 11 disposed in the smoke detection unit 2, a light receiving element 12 such as a photodiode, an air flow sensor 13 for measuring a flow rate of the fan 3 or air, a power source portion 14 for supplying power to the air flow sensor 13, and a
- the smoke detection unit 2 In the black box 21 formed in a substantially cylindrical shape, there are provided the light emitting element 11 for emitting an infrared ray and a stray light portion 22 positioned in a position opposed to the light emitting element 11. Between those, there are provided a condenser lens 24 for condensing emitted light to a curved surface portion of a light trap 23 provided in the stray light portion 22, a smoke detection portion 25 through which allows air passes, the light receiving portion 12, and the like. Note that apertures 26 are provided at appropriate intervals so as to limit applied light. Into the smoke detection portion 25, the sampling air SA which has passed through the piping 4 and has been filtered by a filter 5 is introduced.
- the light trap 23 is formed in a substantially conical shape.
- Light L (not shown) entering the stray light portion is incident on the curved surface of the light trap 23 to be reflected a plurality of times.
- a reflection light amount is set such that the light L is attenuated in every reflection on the curved surface so as not to be diffused as diffused light to the smoke detection portion 25, in other words, to a field range of the light receiving element 12.
- the fire determination portion 1 S includes an amplifier circuit for amplifying an output signal S of the light receiving element 12, an A/D converter for converting the amplifying circuit to a detection level, and a comparator circuit for determining fire when the detection level is equal to or higher than a threshold set in advance.
- a general control of the fire determination portion 15 is performed by a CPU.
- the light trap 23 On the light trap 23, a plurality of times of reflection are performed.
- the light L is attenuated in accordance with the number of times of the reflection. Accordingly, the stray light is not received by the light receiving element 12 and the output signal S is at a low level, so the determination on fire is not made.
- the light L which has passed through the smoke detection portion 25 is reflected as described above by the light trap 23, so the light L is attenuated, thereby not being received as the stray light. Accordingly, even at the time of occurrence of fire, the S/N ratio of the output signal is high, and the fire determination is correctly performed with high sensitivity and high accuracy.
- a diffuser portion 20 On a secondary side of the fan 3 of a gas flow tube P, there is provided a diffuser portion 20.
- the diffuser portion 20 is wider downstream, for example, a divergent pipe (diffuser) having a substantially pyramidal shape such as a cone.
- a flow path merging portion 32 is provided to a side of a base end 20a.
- a flow path branching portion 33 is provided to a side of a distal end 20b located downstream of the flow path merging portion 32.
- a centrifugal fan driven by a DC power source is selected, for example.
- a sampling pipe (not shown) for sucking the sampling air SA is connected to a suction port of the fan 3.
- An exhaust port of the fan is connected to the piping 4 through which the sampling air SA flows into the smoke detection unit 2.
- the fan may be an axial fan. Further, the fan may be driven by an AC power source.
- a diameter D1 of the diffuser portion 20 at the flow path merging portion 32 is formed to be smaller than a diameter D2 thereof at the flow path branching portion 33.
- diameters of both the flow path merging portion 32 and the flow path branching portion 33 are the same. Sizes of the diameters D1 and D2, disposition positions of the flow path branching portion 33 and the flow path merging portion 32, and the like are appropriately selected.
- the divergent pipe has the conical shape but the divergent pipe may have a pyramidal shape.
- the black box 21 of the smoke detection unit 2 On the secondary side of the fan 3, the black box 21 of the smoke detection unit 2 is provided. An inflow port of the smoke detection portion 25 of the black box 21 is connected to the flow path branching portion 33, and an outflow port of the smoke detection portion 25 is connected to the flow path merging portion 32.
- An inflow port of the smoke detection portion 25 of the black box 21 is connected to the flow path branching portion 33, and an outflow port of the smoke detection portion 25 is connected to the flow path merging portion 32.
- V 2 /2g+Z+p/r const.
- V velocity
- Z height
- p pressure
- ⁇ specific weight
- g gravitational acceleration
- smoke particles existing in the sampling air SA flowing through the diffuser portion 20 are sucked from the flow path branching portion 33 and enter the inflow port of the smoke detection portion 25.
- the smoke particles advance in the smoke detection portion 25 while being irradiated with a laser beam of the light emitting element 11 to cause scattered light, and are returned to the diffuser portion 20 through the flow path merging portion 32.
- the differential pressure ⁇ p between the flow path merging portion 32 and the flow path branching portion 33 is always constant when a sampling flow rate is constant. Accordingly, the sampling air SA can be supplied to the smoke detection portion 25 at a constant flow velocity.
- FIGS. 3 and 4 A second embodiment of the present invention will be described with reference to FIGS. 3 and 4 .
- Components denoted by the same reference symbols as those of FIGS. 1 and 2 have the same names and functions.
- a difference between the second embodiment and the first embodiment is that, as differential pressure generation means, instead of the diffuser portion 20, the flow path branching portion and the flow path merging portion are provided in a position where the pressure difference is generated depending on distances from a periphery of a rotor 3 f of the fan 3 on the secondary side of the fan 3.
- a sampling pipe 30 provided in the monitoring area is connected to an intake port 3a of the fan 3 through a suction pipe (gas flow pipe) P1, an exhaust duct (gas flow pipe) P2 is provided to the secondary side of the fan 3, and a choke tube P3 is connected to a rear end of the exhaust duct P2.
- the black box 21 is provided in the vicinity of the exhaust duct P2, the black box 21 is provided.
- the outflow port of the smoke detection portion 25 of the black box 21 is connected to the flow path merging portion 32.
- the flow path merging portion 32 is provided at a position close to the periphery of the rotor 3f of the fan 3, for example, above a bottom surface 21a of the black box 21. The closer the position of the flow path merging portion 32 to the periphery of the rotor 3f of the fan 3 is, the faster the flow velocity becomes and the lower the fluid pressure becomes.
- the inflow port of the smoke detection portion 25 is connected to the flow path branching portion 33.
- the flow path branching portion 33 is provided on the rear end side of the exhaust duct P2, that is, downstream of the flow path merging portion 32 at an interval from the periphery of the rotor 3f of the fan 3. The farther the position of the flow path branching portion 33 from the periphery of the rotor 3f of the fan 3 is, the slower the flow velocity becomes and the higher the fluid pressure becomes. Accordingly, the differential pressure can be adjusted based on a positional relationship between the flow path branching portion 33 and the flow path merging portion 32.
- the pressure difference is caused according to Bernoulli's theorem, and the sampling air SA is introduced into the inflow port of the smoke detection portion 25 from the flow path branching portion 33.
- Smoke particles contained in the sampling air SA are irradiated with a light beam applied from the light emitting element 11 to generate the scattered light, and is discharged from the outflow port to the flow path merging portion 32.
- the flow velocity difference that is, the pressure difference is also constant. Accordingly, the sampling air SA can be introduced into the smoke detection portion 25 at a constant velocity. Further, when the smoke detection portion 25 is provided in the vicinity of the fan 3, the device can be downsized as a whole.
- FIG 5 A third embodiment of the present invention will be described with reference to FIG 5 .
- Components denoted by the same reference symbols as those of FIG 4 have the same names and functions.
- a difference between the third embodiment and the second embodiment of the present invention is that a filter 31 is provided to the flow path branching portion 33 to eliminate foreign substances such as waste in the sampling air SA.
- the filter 31 By the provision of the filter 31, the sampling air containing only smoke particles can be supplied to the smoke detection portion 25, so more accurate smoke detection can be performed.
- FIG 6 A fourth embodiment of the present invention will be described with reference to FIG 6 .
- Components denoted by the same reference symbols as those of FIG 4 have the same names and functions.
- a difference between the fourth embodiment and the second embodiment ( FIG 4 ) of the present invention is that the flow path merging portion 32 is positioned below the bottom surface 21a of the black box 21, that is, the flow path merging portion 32 is provided downstream in the rotation direction of the fan 3.
- the flow velocity in the peripheral portion of the rotor 3f of the fan 3 and in the vicinity thereof is constant in a position on the same periphery. Accordingly, the flow path merging portion 32 can be provided to any position on that periphery.
- the structure of the flow path in which the sampling air SA is introduced can be simplified.
Abstract
Description
- The present invention relates to a smoke detector for optically detecting contaminants such as smoke floating in the air, and a sampling air supplying method therefor.
- A smoke detector is used for preventing fire or as a detecting system at a time of occurrence of fire or in a semiconductor manufacturing plant or a food industry requiring a certain level of environmental conservation.
- As the smoke detector, there is used a high-sensitive smoke detecting apparatus. In the high-sensitive smoke detecting apparatus, air is sucked from a warning area through a sampling pipe by driving a fan, light receiving signals are converted into pulse signals through a comparison between the light receiving signals and a threshold value using a comparator, the light receiving signals being obtained by irradiation of light whose beam spots are focused on smoke particles contained in the sucked air, and the number of the pulse signals are counted, thereby measuring a smoke amount (see Japanese Patent No.
3312712 - In a conventional example, a primary side (suction port side of fan) at which a fluid (sampling air) has not been applied with energy by a fan and a secondary side (exhaust port side) at which the fluid has been applied with energy are connected through a smoke detection portion of a black box, and by using a pressure difference between the primary side and the secondary side, the sampling air is supplied to the smoke detection portion.
- Accordingly, depending on a state of a filter for filtration, which is provided to the fan or a pipe line, a sampling flow rate changes in some cases. When the sampling flow rate changes, due to P-Q characteristics of the fan, fluctuation is caused in the pressure difference between the primary side and the secondary side, and the sampling air cannot be supplied to the smoke detection portion at a preset flow velocity. Therefore, accurate smoke detection becomes difficult.
- The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to enable supply of a sampling air to a smoke detection portion at a stable flow velocity.
- The present invention relates to a smoke detector including: a smoke detection portion having an inflow port and an outflow port; a sampling pipe laid in a monitor space; a gas flow pipe which is connected to the sampling pipe and which houses a fan therein; a flow path branching portion provided to the gas flow pipe on a secondary side of the fan and connected to the inflow port of the smoke detection portion; and a flow path merging portion which is provided to the gas flow pipe on the secondary side of the fan and connected to the outflow port of the smoke detection portion, and at which a pressure of a fluid flowing through the gas flow pipe is lower than a fluid flowing through the gas flow pipe at the flow path branching portion.
- The present invention relates to a smoke detector including: a smoke detection portion having an inflow port and an outflow port; a sampling pipe laid in a monitor space; a fan for connecting the sampling pipe to a suction port; a divergent pipe which has a substantially pyramidal shape connected to an exhaust port of the fan and which is wider downstream; a flow path branching portion provided downstream of the divergent pipe, for supplying a sampling air from the divergent pipe to the smoke detection portion; and a flow path merging portion provided upstream of the flow path branching portion, for performing exhaustion from the smoke detection portion to the divergent pipe.
- The present invention relates to a smoke detector including: a smoke detection portion having an inflow port and an outflow port; a sampling pipe laid in a monitor space; a gas flow pipe which is connected to the sampling pipe and which houses a fan therein; a flow path branching portion provided to the gas flow pipe on a secondary side of the fan and connected to the inflow port of the smoke detection portion; and a flow path merging portion which is provided on the secondary side of the fan and in the vicinity thereof and connected to an outflow port of the smoke detection portion, and at which a pressure of a fluid flowing through the gas flow pipe is lower than a fluid flowing through the gas flow pipe at the flow path branching portion.
- The present invention relates to a sampling air supplying method for a smoke detector, the smoke detector including: a smoke detection portion having an inflow port and an outflow port; a sampling pipe laid in a monitor space; a gas flow pipe which is connected to the sampling pipe and which houses a fan therein; a flow path branching portion provided to the gas flow pipe on a secondary side of the fan and connected to the inflow port of the smoke detection portion; and a flow path merging portion which is provided on the secondary side of the fan and in the vicinity thereof and connected to an outflow port of the smoke detection portion, and at which a pressure of a fluid flowing through the gas flow pipe is lower than a fluid flowing through the gas flow pipe at the flow path branching portion, the sampling air supplying method including introducing a part of the fluid from the flow path branching portion to the smoke detection portion owing to a pressure difference in the fluid on the secondary side of the fan.
- The present invention is structured as described above. Accordingly, owing to the pressure difference in the fluid between the flow path branching portion and the flow path merging portion, a part of the sampling air flowing through the gas flow pipe is introduced from the flow path branching portion into the smoke detection portion, is allowed to pass through the smoke detection portion, and is returned into the gas flow pipe from the flow path merging portion. Therefore, the sampling air can be supplied to the smoke detection portion at a constant flow velocity, so accurate smoke detection can be performed.
- In the accompanying drawings:
-
FIG. 1 is a structural view showing a first embodiment of the present invention; -
FIG 2 is a vertical sectional view showing the first embodiment of the present invention; -
FIG 3 is a front view showing a fan according to a second embodiment of the present invention; -
FIG 4 is a vertical sectional view showing the second embodiment of the present invention; -
FIG 5 is a vertical sectional view showing a third embodiment of the present invention; and -
FIG 6 is a vertical sectional view showing a fourth embodiment of the present invention. - A first embodiment of the present invention will be described with reference to
FIGS. 1 and2 . - As shown in
FIG. 1 , a smoke detector 1 includes asmoke detection unit 2 provided with ablack box 21, afan 3 for sending an air (sampling air) SA to be sensed by thesmoke detection unit 2, a piping 4 constituting an air passage, alight emitting element 11 disposed in thesmoke detection unit 2, alight receiving element 12 such as a photodiode, anair flow sensor 13 for measuring a flow rate of thefan 3 or air, apower source portion 14 for supplying power to theair flow sensor 13, and afire determination portion 15 connected to alight receiving element 12. - Next, a description will be made of the
smoke detection unit 2. In theblack box 21 formed in a substantially cylindrical shape, there are provided thelight emitting element 11 for emitting an infrared ray and astray light portion 22 positioned in a position opposed to thelight emitting element 11. Between those, there are provided acondenser lens 24 for condensing emitted light to a curved surface portion of alight trap 23 provided in thestray light portion 22, asmoke detection portion 25 through which allows air passes, thelight receiving portion 12, and the like. Note thatapertures 26 are provided at appropriate intervals so as to limit applied light. Into thesmoke detection portion 25, the sampling air SA which has passed through the piping 4 and has been filtered by afilter 5 is introduced. - The
light trap 23 according to the first embodiment of the present invention is formed in a substantially conical shape. Light L (not shown) entering the stray light portion is incident on the curved surface of thelight trap 23 to be reflected a plurality of times. There is provided a structure by which, a reflection light amount is set such that the light L is attenuated in every reflection on the curved surface so as not to be diffused as diffused light to thesmoke detection portion 25, in other words, to a field range of thelight receiving element 12. - Note that the fire determination portion 1 S includes an amplifier circuit for amplifying an output signal S of the
light receiving element 12, an A/D converter for converting the amplifying circuit to a detection level, and a comparator circuit for determining fire when the detection level is equal to or higher than a threshold set in advance. A general control of thefire determination portion 15 is performed by a CPU. - In the following, a description will be made of a smoke detection operation according to the first embodiment of the present invention.
- In a normal state, air sucked from a monitor space by the
fan 3 flows from a top to a bottom of thesmoke detection portion 25. When the air is clean, the light L is not scattered in thesmoke detection portion 25, and the light L enter the inside of thestray light portion 22 while being condensed and in a state where a focal point is adjusted on the curved surface of thelight trap 23. - On the
light trap 23, a plurality of times of reflection are performed. The light L is attenuated in accordance with the number of times of the reflection. Accordingly, the stray light is not received by thelight receiving element 12 and the output signal S is at a low level, so the determination on fire is not made. - At the time of occurrence of fire, smoke particles float in the sucked air. When the smoke particles are irradiated with the light L, the scattered light is generated in the
smoke detection portion 25. The scattered light is received by thelight receiving element 12. The output signal S corresponding to a received light amount is derived. The output signal S is supplied to thefire determination portion 15 and a processing of the signal is performed to notify the occurrence of fire by display or sound. - The light L which has passed through the
smoke detection portion 25 is reflected as described above by thelight trap 23, so the light L is attenuated, thereby not being received as the stray light. Accordingly, even at the time of occurrence of fire, the S/N ratio of the output signal is high, and the fire determination is correctly performed with high sensitivity and high accuracy. - On a secondary side of the
fan 3 of a gas flow tube P, there is provided adiffuser portion 20. Thediffuser portion 20 is wider downstream, for example, a divergent pipe (diffuser) having a substantially pyramidal shape such as a cone. A flowpath merging portion 32 is provided to a side of abase end 20a. Further, a flowpath branching portion 33 is provided to a side of adistal end 20b located downstream of the flowpath merging portion 32. - For the
fan 3, a centrifugal fan driven by a DC power source is selected, for example. A sampling pipe (not shown) for sucking the sampling air SA is connected to a suction port of thefan 3. An exhaust port of the fan is connected to the piping 4 through which the sampling air SA flows into thesmoke detection unit 2. - Note that the fan may be an axial fan. Further, the fan may be driven by an AC power source.
- A diameter D1 of the
diffuser portion 20 at the flowpath merging portion 32 is formed to be smaller than a diameter D2 thereof at the flowpath branching portion 33. However, diameters of both the flowpath merging portion 32 and the flowpath branching portion 33 are the same. Sizes of the diameters D1 and D2, disposition positions of the flowpath branching portion 33 and the flowpath merging portion 32, and the like are appropriately selected. In the illustrated example, the divergent pipe has the conical shape but the divergent pipe may have a pyramidal shape. - On the secondary side of the
fan 3, theblack box 21 of thesmoke detection unit 2 is provided. An inflow port of thesmoke detection portion 25 of theblack box 21 is connected to the flowpath branching portion 33, and an outflow port of thesmoke detection portion 25 is connected to the flowpath merging portion 32. For a structure of thesmoke detection unit 2, for the sake of description, components different from those ofFIG 1 are used, but a principle thereof is the same. - Next, an operation according to the first embodiment of the present invention will be described.
- When the
fan 3 is driven, air A in the monitor space is sucked into a gas flow pipe P through the sampling pipe (not shown) and passes through thediffuser portion 20 to be exhausted. However, in this case, a flow velocity at the flowpath merging portion 32 in thediffuser portion 20 differs from a flow velocity at the flowpath branching portion 33 therein, so a pressure difference is caused between those portions. - That is, according to Bernoulli's theorem: V2/2g+Z+p/r=const. (V: velocity, Z: height, p: pressure, γ: specific weight, and g: gravitational acceleration), when the inner diameter is larger than that of flow velocity V=4Q (flow rate)/D2π, the flow velocity is reduced. Accordingly, a relationship of a flow velocity V1 at the flow
path merging portion 32>a flow velocity V2 at the flowpath branching portion 33 is obtained. Therefore, a differential pressure Δp with respect to thesmoke detection portion 25, that is, a pressure p2 of the flow path branching portion 33-a pressure p1 of the flowpath merging portion 32 is derived by the following equation according to the Bernoulli's theorem. - Owing to generation of the pressure difference, smoke particles existing in the sampling air SA flowing through the
diffuser portion 20 are sucked from the flowpath branching portion 33 and enter the inflow port of thesmoke detection portion 25. The smoke particles advance in thesmoke detection portion 25 while being irradiated with a laser beam of thelight emitting element 11 to cause scattered light, and are returned to thediffuser portion 20 through the flowpath merging portion 32. - The differential pressure Δp between the flow
path merging portion 32 and the flowpath branching portion 33 is always constant when a sampling flow rate is constant. Accordingly, the sampling air SA can be supplied to thesmoke detection portion 25 at a constant flow velocity. - A second embodiment of the present invention will be described with reference to
FIGS. 3 and4 . Components denoted by the same reference symbols as those ofFIGS. 1 and2 have the same names and functions. - A difference between the second embodiment and the first embodiment is that, as differential pressure generation means, instead of the
diffuser portion 20, the flow path branching portion and the flow path merging portion are provided in a position where the pressure difference is generated depending on distances from a periphery of arotor 3 f of thefan 3 on the secondary side of thefan 3. - That is, as shown in
FIG 4 , asampling pipe 30 provided in the monitoring area is connected to anintake port 3a of thefan 3 through a suction pipe (gas flow pipe) P1, an exhaust duct (gas flow pipe) P2 is provided to the secondary side of thefan 3, and a choke tube P3 is connected to a rear end of the exhaust duct P2. In the vicinity of the exhaust duct P2, theblack box 21 is provided. - The outflow port of the
smoke detection portion 25 of theblack box 21 is connected to the flowpath merging portion 32. However, the flowpath merging portion 32 is provided at a position close to the periphery of therotor 3f of thefan 3, for example, above abottom surface 21a of theblack box 21. The closer the position of the flowpath merging portion 32 to the periphery of therotor 3f of thefan 3 is, the faster the flow velocity becomes and the lower the fluid pressure becomes. - Further, the inflow port of the
smoke detection portion 25 is connected to the flowpath branching portion 33. However, the flowpath branching portion 33 is provided on the rear end side of the exhaust duct P2, that is, downstream of the flowpath merging portion 32 at an interval from the periphery of therotor 3f of thefan 3. The farther the position of the flowpath branching portion 33 from the periphery of therotor 3f of thefan 3 is, the slower the flow velocity becomes and the higher the fluid pressure becomes. Accordingly, the differential pressure can be adjusted based on a positional relationship between the flowpath branching portion 33 and the flowpath merging portion 32. - In the second embodiment of the present invention, when the air A in the monitor space is sucked through a
suction port 34 of thesampling pipe 30 by the rotation of thefan 3, the air A passes through the suction pipe P 1 and flows into the exhaust duct P2. ' - In this case, a peripheral velocity V of the
fan 3 is expressed by an equation
a flow velocity V1 at the flowpath merging portion 32 spaced apart from the periphery of therotor 3f of thefan 3 by a distance R1 is expressed by an equation
and a flow velocity V2 at a position (flow path branching portion 33) spaced apart from therotor 3f of thefan 3 by a distance R2 is expressed by an equation
(coefficient of viscosity of air < 1) - Accordingly, there is a flow velocity difference with a relationship of V1>V2. Therefore, the pressure difference is caused according to Bernoulli's theorem, and the sampling air SA is introduced into the inflow port of the
smoke detection portion 25 from the flowpath branching portion 33. Smoke particles contained in the sampling air SA are irradiated with a light beam applied from thelight emitting element 11 to generate the scattered light, and is discharged from the outflow port to the flowpath merging portion 32. - In the second embodiment of the present invention, when the rpm of the
fan 3 is constant, the flow velocity difference, that is, the pressure difference is also constant. Accordingly, the sampling air SA can be introduced into thesmoke detection portion 25 at a constant velocity. Further, when thesmoke detection portion 25 is provided in the vicinity of thefan 3, the device can be downsized as a whole. - A third embodiment of the present invention will be described with reference to
FIG 5 . Components denoted by the same reference symbols as those ofFIG 4 have the same names and functions. - A difference between the third embodiment and the second embodiment of the present invention is that a
filter 31 is provided to the flowpath branching portion 33 to eliminate foreign substances such as waste in the sampling air SA. By the provision of thefilter 31, the sampling air containing only smoke particles can be supplied to thesmoke detection portion 25, so more accurate smoke detection can be performed. - A fourth embodiment of the present invention will be described with reference to
FIG 6 . Components denoted by the same reference symbols as those ofFIG 4 have the same names and functions. - A difference between the fourth embodiment and the second embodiment (
FIG 4 ) of the present invention is that the flowpath merging portion 32 is positioned below thebottom surface 21a of theblack box 21, that is, the flowpath merging portion 32 is provided downstream in the rotation direction of thefan 3. - The flow velocity in the peripheral portion of the
rotor 3f of thefan 3 and in the vicinity thereof is constant in a position on the same periphery. Accordingly, the flowpath merging portion 32 can be provided to any position on that periphery. In the fourth embodiment of the present invention, as compared to the second embodiment, the structure of the flow path in which the sampling air SA is introduced can be simplified.
Claims (4)
- A smoke detector, comprising:a smoke detection portion having an inflow port and an outflow port;a sampling pipe laid in a monitor space;a gas flow pipe which is connected to the sampling pipe and which houses a fan therein;a flow path branching portion provided to the gas flow pipe on a secondary side of the fan and connected to the inflow port of the smoke detection portion; anda flow path merging portion which is provided to the gas flow pipe on the secondary side of the fan and connected to the outflow port of the smoke detection portion, and at which a pressure of a fluid flowing through the gas flow pipe is lower than a fluid flowing through the gas flow pipe at the flow path branching portion.
- A smoke detector, comprising:a smoke detection portion having an inflow port and an outflow port;a sampling pipe laid in a monitor space;a fan for connecting the sampling pipe to a suction port;a divergent pipe which has a substantially pyramidal shape connected to an exhaust port of the fan and which is wider downstream;a flow path branching portion provided downstream of the divergent pipe, for supplying a sampling air from the divergent pipe to the smoke detection portion; anda flow path merging portion provided upstream of the flow path branching portion, for performing exhaustion from the smoke detection portion to the divergent pipe.
- A smoke detector, comprising:a smoke detection portion having an inflow port and an outflow port;a sampling pipe laid in a monitor space;a gas flow pipe which is connected to the sampling pipe and which houses a fan therein;a flow path branching portion provided to the gas flow pipe on a secondary side of the fan and connected to the inflow port of the smoke detection portion; anda flow path merging portion which is provided on the secondary side of the fan and in the vicinity thereof and connected to an outflow port of the smoke detection portion, and at which a pressure of a fluid flowing through the gas flow pipe is lower than a fluid flowing through the gas flow pipe at the flow path branching portion.
- A sampling air supplying method for a smoke detector,
the smoke detector including:a smoke detection portion having an inflow port and an outflow port;a sampling pipe laid in a monitor space;a gas flow pipe which is connected to the sampling pipe and which houses a fan therein;a flow path branching portion provided to the gas flow pipe on a secondary side of the fan and connected to the inflow port of the smoke detection portion; anda flow path merging portion which is provided on the secondary side of the fan and in the vicinity thereof and connected to an outflow port of the smoke detection portion, and at which a pressure of a fluid flowing through the gas flow pipe is lower than a fluid flowing through the gas flow pipe at the flow path branching portion,the sampling air supplying method comprising introducing a part of the fluid from the flow path branching portion to the smoke detection portion owing to a pressure difference in the fluid on the secondary side of the fan.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2007091276A JP4932567B2 (en) | 2007-03-30 | 2007-03-30 | Smoke detector and sampling air supply method thereof |
Publications (3)
Publication Number | Publication Date |
---|---|
EP1975896A2 true EP1975896A2 (en) | 2008-10-01 |
EP1975896A3 EP1975896A3 (en) | 2009-03-18 |
EP1975896B1 EP1975896B1 (en) | 2010-05-05 |
Family
ID=39535800
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP08251196A Not-in-force EP1975896B1 (en) | 2007-03-30 | 2008-03-28 | Smoke detector and sampling air supplying method for smoke detector |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP1975896B1 (en) |
JP (1) | JP4932567B2 (en) |
KR (1) | KR101391550B1 (en) |
CN (1) | CN101275910B (en) |
AU (1) | AU2008201308B2 (en) |
DE (1) | DE602008001120D1 (en) |
TW (1) | TWI437513B (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8907802B2 (en) | 2012-04-29 | 2014-12-09 | Valor Fire Safety, Llc | Smoke detector with external sampling volume and ambient light rejection |
US8947244B2 (en) | 2012-04-29 | 2015-02-03 | Valor Fire Safety, Llc | Smoke detector utilizing broadband light, external sampling volume, and internally reflected light |
US9140646B2 (en) | 2012-04-29 | 2015-09-22 | Valor Fire Safety, Llc | Smoke detector with external sampling volume using two different wavelengths and ambient light detection for measurement correction |
US9482607B2 (en) | 2012-04-29 | 2016-11-01 | Valor Fire Safety, Llc | Methods of smoke detecting using two different wavelengths of light and ambient light detection for measurement correction |
CN117746567A (en) * | 2024-02-20 | 2024-03-22 | 四川千页科技股份有限公司 | Energy storage power station composite fire detection system and method |
CN117746567B (en) * | 2024-02-20 | 2024-04-26 | 四川千页科技股份有限公司 | Energy storage power station composite fire detection system and method |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8098166B2 (en) * | 2009-04-23 | 2012-01-17 | Honeywell International Inc. | Variable air speed aspirating smoke detector |
AU2010255496B2 (en) * | 2009-06-05 | 2015-01-29 | Garrett Thermal Systems Limited | Gas detector apparatus |
JP5280347B2 (en) * | 2009-12-17 | 2013-09-04 | 能美防災株式会社 | Photoelectric smoke detector |
CN101763708B (en) * | 2009-12-28 | 2012-01-18 | 公安部沈阳消防研究所 | Wind pipe smoke-sensing fire detector |
CN101958032B (en) * | 2010-09-27 | 2012-05-23 | 江苏大学 | Wireless sensor smoke detection device for fire protection |
CN103063614A (en) * | 2013-01-04 | 2013-04-24 | 吉林大学 | Laser type extinction smoke meter system for measuring smoke intensity of tail gas of diesel engine |
CN108837651B (en) * | 2018-06-24 | 2020-11-13 | 江苏兰丰环保科技有限公司 | Desulfurization denitration dust removal coprocessing device |
CN109030295A (en) * | 2018-08-30 | 2018-12-18 | 安徽乐锦记食品有限公司 | A kind of bread processing anomaly alarming device smog extraction detection device |
US11506586B2 (en) | 2020-08-17 | 2022-11-22 | Carrier Corporation | Photoelectric smoke sensor tube |
CN115240358A (en) * | 2022-05-25 | 2022-10-25 | 中国船舶重工集团公司第七0三研究所 | A formula of breathing in smoke is felt and is surveyed structure for smog concentration detection |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3312712B2 (en) | 1995-01-31 | 2002-08-12 | ホーチキ株式会社 | Optimal threshold setting method for high-sensitivity smoke detector |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3678487A (en) * | 1971-02-08 | 1972-07-18 | Environment One Corp | Multi-zone incipient or actual fire and/or dangerous gas detection system |
JPS5851392A (en) * | 1981-09-24 | 1983-03-26 | Fujitsu Ltd | File copying system |
US5103212A (en) * | 1989-07-03 | 1992-04-07 | Worcester Polytechnic Institute | Balanced fluid flow delivery system |
JP3648307B2 (en) * | 1995-11-24 | 2005-05-18 | 日本フエンオール株式会社 | Smoke detection system |
US5926098A (en) * | 1996-10-24 | 1999-07-20 | Pittway Corporation | Aspirated detector |
CA2299919A1 (en) * | 1999-03-04 | 2000-09-04 | George A. Schoenfelder | Duct detector |
JP3714926B2 (en) * | 2002-08-22 | 2005-11-09 | ホーチキ株式会社 | Sampling tube smoke detector |
-
2007
- 2007-03-30 JP JP2007091276A patent/JP4932567B2/en active Active
-
2008
- 2008-02-27 KR KR1020080017722A patent/KR101391550B1/en not_active IP Right Cessation
- 2008-03-07 CN CN200810084922XA patent/CN101275910B/en active Active
- 2008-03-17 TW TW097109372A patent/TWI437513B/en not_active IP Right Cessation
- 2008-03-20 AU AU2008201308A patent/AU2008201308B2/en not_active Ceased
- 2008-03-28 EP EP08251196A patent/EP1975896B1/en not_active Not-in-force
- 2008-03-28 DE DE602008001120T patent/DE602008001120D1/en active Active
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3312712B2 (en) | 1995-01-31 | 2002-08-12 | ホーチキ株式会社 | Optimal threshold setting method for high-sensitivity smoke detector |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8907802B2 (en) | 2012-04-29 | 2014-12-09 | Valor Fire Safety, Llc | Smoke detector with external sampling volume and ambient light rejection |
US8947244B2 (en) | 2012-04-29 | 2015-02-03 | Valor Fire Safety, Llc | Smoke detector utilizing broadband light, external sampling volume, and internally reflected light |
US8947243B2 (en) | 2012-04-29 | 2015-02-03 | Valor Fire Safety, Llc | Smoke detector with external sampling volume and utilizing internally reflected light |
US8952821B2 (en) | 2012-04-29 | 2015-02-10 | Valor Fire Safety, Llc | Smoke detector utilizing ambient-light sensor, external sampling volume, and internally reflected light |
US9140646B2 (en) | 2012-04-29 | 2015-09-22 | Valor Fire Safety, Llc | Smoke detector with external sampling volume using two different wavelengths and ambient light detection for measurement correction |
US9142112B2 (en) | 2012-04-29 | 2015-09-22 | Valor Fire Safety, Llc | Smoke detector with external sampling volume using two different wavelengths and ambient light detection for measurement correction |
US9142113B2 (en) | 2012-04-29 | 2015-09-22 | Valor Fire Safety, Llc | Smoke detector with external sampling volume using two different wavelengths and ambient light detection for measurement correction |
US9470626B2 (en) | 2012-04-29 | 2016-10-18 | Valor Fire Safety, Llc | Method of smoke detection with direct detection of light and detection of light reflected from an external sampling volume |
US9482607B2 (en) | 2012-04-29 | 2016-11-01 | Valor Fire Safety, Llc | Methods of smoke detecting using two different wavelengths of light and ambient light detection for measurement correction |
US10041877B2 (en) | 2012-04-29 | 2018-08-07 | Valor Fire Safety, Llc | Smoke detection using two different wavelengths of light and additional detection for measurement correction |
US10712263B2 (en) | 2012-04-29 | 2020-07-14 | Valor Fire Safety, Llc | Smoke detection using two different wavelengths of light and additional detection for measurement correction |
CN117746567A (en) * | 2024-02-20 | 2024-03-22 | 四川千页科技股份有限公司 | Energy storage power station composite fire detection system and method |
CN117746567B (en) * | 2024-02-20 | 2024-04-26 | 四川千页科技股份有限公司 | Energy storage power station composite fire detection system and method |
Also Published As
Publication number | Publication date |
---|---|
EP1975896A3 (en) | 2009-03-18 |
EP1975896B1 (en) | 2010-05-05 |
CN101275910B (en) | 2011-06-08 |
DE602008001120D1 (en) | 2010-06-17 |
TWI437513B (en) | 2014-05-11 |
KR20080089167A (en) | 2008-10-06 |
AU2008201308A1 (en) | 2008-10-16 |
CN101275910A (en) | 2008-10-01 |
TW200901093A (en) | 2009-01-01 |
JP2008250684A (en) | 2008-10-16 |
KR101391550B1 (en) | 2014-05-07 |
JP4932567B2 (en) | 2012-05-16 |
AU2008201308B2 (en) | 2011-07-28 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP1975896B1 (en) | Smoke detector and sampling air supplying method for smoke detector | |
US7808393B2 (en) | Smoke detector and sampling air supplying method for smoke detector | |
EP1967843B1 (en) | Smoke detector | |
AU2009200921B2 (en) | Smoke detector | |
JP5009208B2 (en) | smoke detector | |
JP2008234416A (en) | Smoke detector | |
AU2011218748B2 (en) | Smoke detector | |
AU2011218751B2 (en) | Smoke detector | |
KR20160029183A (en) | Detection circuit of micro dust and organism detection apparatus |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR |
|
AX | Request for extension of the european patent |
Extension state: AL BA MK RS |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
AK | Designated contracting states |
Kind code of ref document: A3 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR |
|
AX | Request for extension of the european patent |
Extension state: AL BA MK RS |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: G08B 17/113 20060101ALI20090206BHEP Ipc: G08B 17/107 20060101ALI20090206BHEP Ipc: G08B 17/10 20060101AFI20080701BHEP |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
17P | Request for examination filed |
Effective date: 20090918 |
|
AKX | Designation fees paid |
Designated state(s): CH DE FR GB LI |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: G08B 17/10 20060101AFI20091028BHEP |
|
GRAS | Grant fee paid |
Free format text: ORIGINAL CODE: EPIDOSNIGR3 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): CH DE FR GB LI |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: FG4D |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: NV Representative=s name: WILLIAM BLANC & CIE CONSEILS EN PROPRIETE INDUSTRI Ref country code: CH Ref legal event code: EP |
|
REF | Corresponds to: |
Ref document number: 602008001120 Country of ref document: DE Date of ref document: 20100617 Kind code of ref document: P |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PFA Owner name: NOHMI BOSAI LTD. Free format text: NOHMI BOSAI LTD.#7-3, KUDAN MINAMI 4-CHOME#CHIYODA-KU TOKYO (JP) -TRANSFER TO- NOHMI BOSAI LTD.#7-3, KUDAN MINAMI 4-CHOME#CHIYODA-KU TOKYO (JP) |
|
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed |
Effective date: 20110208 |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R097 Ref document number: 602008001120 Country of ref document: DE Effective date: 20110207 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PCAR Free format text: NOVAGRAAF SWITZERLAND SA;CHEMIN DE L'ECHO 3;1213 ONEX (CH) |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 8 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20150324 Year of fee payment: 8 Ref country code: CH Payment date: 20150313 Year of fee payment: 8 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20150309 Year of fee payment: 8 Ref country code: GB Payment date: 20150325 Year of fee payment: 8 |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R119 Ref document number: 602008001120 Country of ref document: DE |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20160328 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST Effective date: 20161130 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: CH Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20160331 Ref country code: LI Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20160331 Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20160328 Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20161001 Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20160331 |