Smoke sensor

Abstract

An object of the present invention is to provide a suction-type smoke detector in which dust is less likely to accumulate in the suction port. [Solution] The smoke detector of the present invention is an suction-type smoke detector equipped with an intake port and an intake device, and is characterized in that the intake device draws in outside air through the intake port and draws it into the smoke detector, and removes dust by releasing air outside through the intake port.

Description

[Technical Field]

[0001] The present invention relates to a suction-type smoke detector that is capable of drawing in outside air. [Background technology]

[0002] Suction-type smoke detectors, which detect smoke by drawing in outside air into the device, can detect smoke early by forcibly generating an airflow. Patent Document 1 describes a spot-type smoke detector that draws in outside air by incorporating a suction fan. Patent Document 2 describes a smoke detector that detects smoke by drawing in outside air from an air suction hole through an air sampling tube. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-60196 [Patent Document 2] Japanese Patent Application Publication No. 9-147255 Summary of the Invention [Problem to be solved by the invention]

[0004] The intake port of a smoke detector is equipped with a filter or has small holes to prevent dust from entering from the outside air. With such suction-type smoke detectors, dust can accumulate in the intake port over time, making it difficult for outside air to be drawn in. For this reason, the intake port must be inspected and cleaned during regular inspections.

[0005] An object of one embodiment of the present invention is to provide a suction-type smoke detector that is less likely to accumulate dust in the suction port. [Means for solving the problem]

[0006] The smoke detector in one embodiment of the present invention is an suction-type smoke detector equipped with an intake port and an intake device, and the intake device is characterized in that it draws in outside air through the intake port and draws it into the smoke detector, and also removes dust by releasing air outside through the intake port. [Effects of the Invention]

[0007] The present invention can provide a suction-type smoke detector in which dust is less likely to accumulate in the suction port. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram showing the internal configuration of the smoke detector according to the first embodiment. [Figure 2] FIG. 3 is a cross-sectional view of the smoke detector during suction in the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view of the smoke detector according to the first embodiment when discharging smoke. [Figure 4] FIG. 11 is a cross-sectional view of the smoke detector during suction in the third embodiment. [Figure 5] FIG. 10 is a diagram showing a smoke detector during inhalation in the fourth embodiment. [Figure 6] FIG. 10 is a diagram showing a smoke detector during emission in the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION [Example]

[0009] FIG. 1 shows the internal configuration of a smoke detector 1 in Example 1. The smoke detector 1 is of the suction type and includes a control device 11, a smoke detector 12, a fan 13, a motor 14, and a drive circuit 15. The smoke detector 12 includes a light-emitting element 121 and a light-receiving element 122. The control device 11 is connected to the smoke detector 12, controls the light emission of the light-emitting element 121, and detects light scattered by smoke with the light-receiving element 122 to determine the presence or absence of smoke. The control device 11 also controls the drive circuit 15, and uses the drive voltage generated by the drive circuit 15 to rotate the motor 14, which in turn rotates the fan 13. The fan 13, motor 14, and drive circuit 15 form a suction device. The control device 11 includes a CPU and memory.

[0010] 2 shows a cross-sectional view of the smoke detector 1 during suction in Example 1. The smoke detector 1 is attached to the underside of a ceiling panel C and has a smoke detector 12 at the bottom inside. A fan 13 and a motor 14 for rotating the fan 13 are provided above the smoke detector 12. An intake port 16 is provided in a cylindrical region around the smoke detector 12 at the bottom of the smoke detector 1. An exhaust port 17 is provided in a cylindrical region at the top of the smoke detector 1.

[0011] In smoke detector 1, fan 13 normally rotates under the control of control device 11, generating airflow AC as indicated by the arrow in FIG. 2. As fan 13 rotates, airflow AC is generated and outside air is drawn in through intake port 16. Airflow AC passes from intake port 16, through smoke detector 12, and fan 13, and is discharged from surrounding outlets 17 at the top of smoke detector 1. This generates airflow AC outside intake port 16, allowing outside air near intake port 16 to be quickly drawn into smoke detector 12.

[0012] Intake port 16 of smoke detector 1 is a mesh-like cylindrical plate to prevent insects and other insects from entering the interior. If outside air is taken in through intake port 16 via airflow AC for a long period of time, dust will accumulate at intake port 16, weakening the airflow AC. Therefore, in smoke detector 1 of Example 1, intake and discharge through intake port 16 are repeated at predetermined time intervals. Therefore, when a predetermined time has elapsed since fan 13 was rotated, control device 11 sends a signal to drive circuit 15 to rotate fan 13 in the reverse direction. This state is shown in FIG. 3.

[0013] 3 is a cross-sectional view of smoke detector 1 during discharge in Example 1. As fan 13 rotates in the reverse direction, airflow AC is reversed to become reverse airflow BC, and air is discharged to the outside from inlet 16. As a result, dust accumulated at inlet 16 is blown away and removed from inlet 16. In Example 1, smoke is taken in through inlet 16 and detected, so the time for which fan 13 is rotated in the reverse direction is short enough that it does not interfere with fire detection.

[0014] 3, even if smoke is taken in through outlet 17 to create reverse airflow BC, the smoke will pass through smoke detector 12 if it is present near outlet 17. Therefore, as a modified example, the airflow AC may be reversed at predetermined time intervals to create reverse airflow BC, without particularly shortening the time for which fan 13 is reversed, to prevent dust from accumulating at inlet 16 or outlet 17. For example, suction and discharge from inlet 16 may be repeated at predetermined time intervals.

[0015] In the first embodiment, the airflow AC is normally set to allow early detection of smoke, and occasionally the airflow AC is changed to a reverse airflow BC for a short period of time. During the reverse airflow BC period when air is discharged to the outside from the intake port 16, the air can be discharged at a higher pressure than when outside air is drawn in through the intake port 16 and drawn into the smoke detection unit 12. To discharge the air at a higher pressure, the fan 13 is rotated at high speed for a short period of time. This ensures that dust accumulated in the intake port 16 is removed. [Example]

[0016] The smoke detector 1 of the second embodiment detects the degree of dust accumulation. Since the basic configuration of the smoke detector 1 of the second embodiment is the same as that of the smoke detector 1 of the first embodiment, the same reference numerals and FIGS. 1 to 3 will be used for the description. The smoke detector 1 of the second embodiment differs from the smoke detector 1 of the first embodiment in the program stored in the memory of the control device 11. In the second embodiment, the light receiving element 122 of the first embodiment is used as a dust detection device. The smoke detector 1 of the second embodiment is also of the suction type.

[0017] When dust accumulates in the intake port 16, some of the dust enters the smoke detector 12 and is illuminated by the light-emitting element 121. The light reflected or scattered by the dust is then captured by the light-receiving element 122. Because dust floating in the smoke detector 12 increases slowly, the signal output from the light-receiving element 122 due to the reflection or scattering of dust increases slowly over the long term, unlike the signal output due to the presence of smoke. When the output, which increases over the long term, reaches a predetermined value or greater, the control device 11 determines that dust accumulation has been detected. Specifically, the output of the light-receiving element 122 is passed through a low-pass filter, and if the value obtained by removing high-frequency components is equal to or greater than a predetermined value, the control device 11 determines that dust accumulation has been detected. Alternatively, the control device 11 may determine that dust accumulation has been detected if the number of pulse signals generated within a predetermined period due to dust passing through (the frequency of the pulse signals) is equal to or greater than a predetermined number. In the second embodiment, the smoke detector 12 functions as a dust detector. When the control device 11 determines that the signal output from the light receiving element 122 is due to dust, it reverses the rotation of the motor 14 to generate a reverse airflow BC. This makes it possible to remove dust accumulated in the intake port 16, as in the first embodiment. Whether or not the signal from the light receiving element 122 indicates the accumulation of dust in the intake port 16 may be determined by a determination criterion learned by machine learning in the control device 11. Note that when a short-term increase in output is detected, the control device 11 determines that smoke has been detected, and transmits a smoke detection signal from the smoke detector 1. [Example]

[0018] The smoke detector 2 of Example 3 is also a suction type and detects the degree of dust accumulation, similar to Example 2. FIG. 4 shows a cross-sectional view of the smoke detector 2 during suction in Example 3. Like the smoke detectors 1 of Examples 1 and 2, the smoke detector 2 is attached to the underside of a ceiling panel C and includes a control device 21, a smoke detector 22, a fan 23, a motor 24, and a drive circuit 25. The smoke detector 22 includes a light-emitting element 221 and a light-receiving element 222. The smoke detector 22 also includes an intake port 26 and an exhaust port 27. The control device 21, drive circuit 25, light-emitting element 221, and light-receiving element 222 are not shown. The fan 23, motor 24, and drive circuit 25 constitute a suction device. Unlike the smoke detector 1, the smoke detector 2 includes a pressure sensor 28 near the smoke detector 22. The pressure sensor 28 measures air pressure and outputs a pressure signal to the control device 21, functioning as a dust detector.

[0019] In the smoke detector 2 of the third embodiment, the motor 24 is temporarily stopped at predetermined time intervals under the control of the control device 21. The control device 21 then compares the air pressure when the motor 24 is stopped with the air pressure when the motor 24 is driven and the fan 23 is rotating. The air pressure when the fan 23 is rotating is the air pressure generated by the suction device.

[0020] As shown in FIG. 4 , when motor 24 is driven and fan 23 rotates, air around pressure sensor 8 is sucked in and passes through smoke detection unit 22. Because inlet 26 is a mesh-like cylindrical plate, similar to inlet 16 in smoke detector 1 of Example 1, resistance is generated at inlet 26 by airflow AC, and the air pressure measured by pressure sensor 28 decreases compared to the air pressure when fan 23 is stopped. However, when no dust accumulates at inlet 16, the difference between the air pressure when motor 24 is stopped and the air pressure when motor 24 is driven and fan 23 is rotating is small. On the other hand, when dust accumulates at inlet 26, resistance increases in response to the accumulation, and the air pressure measured by pressure sensor 28 decreases further. The difference between the air pressure when motor 24 is stopped and the air pressure when motor 24 is driven and fan 23 is rotating increases as dust accumulates. If the difference between the air pressure when motor 24 is stopped and the air pressure when motor 24 is driven and fan 23 is rotating is equal to or greater than a predetermined value, control device 21 determines that dust has accumulated in intake port 26 and detects the accumulation of dust. Then, upon detecting the accumulation of dust, control device 21 temporarily reverses motor 24 to generate a reverse airflow BC, thereby removing dust adhering to intake port 26.

[0021] In the third embodiment, a pressure sensor 28 is provided near the smoke detection unit 22 inside the smoke detector 2, and the accumulation of dust is detected by the pressure difference between when the fan 23 is rotating and when it is stopped. However, in addition to the pressure sensor 28, a pressure sensor may be provided outside the smoke detector 2, and the accumulation of dust may be detected by the pressure difference between the inside and outside of the smoke detector 2. [Example]

[0022] Example 4 is a smoke detector 3 that uses an air sampling tube 38. FIG. 5 shows a cross-sectional view of the smoke detector 3 in Example 4 during suction. Similar to smoke detectors 1 and 2, the smoke detector 3 equipped with the air sampling tube 38 includes a control device 31, a smoke detection unit 32, a fan 33, a motor 34, and a drive circuit 35. The smoke detection unit 32 includes a light-emitting element 321 and a light-receiving element 322. The smoke detection unit 32 has an outlet 37, and the air sampling tube 38 has an intake port 36. Note that the control device 31, motor 34, drive circuit 35, light-emitting element 321, and light-receiving element 322 are not shown. The fan 33, motor 34, and drive circuit 35 constitute a suction device. The smoke detector 3 of Example 4 is also a suction type.

[0023] In the smoke detector 3, the fan 33 normally rotates under the control of the control device 31. When the fan 33 rotates, it generates an airflow AC, which draws in outside air from the inlet 36. A plurality of inlets 36 are provided near the tip of the air sampling pipe 38, which branches into multiple branches. The outside air becomes airflow AC, enters the air sampling pipe 38 from the inlet 36, passes through the air sampling pipe 38, and is collected there. The airflow AC causes the air to pass from the inlet 36 through the air sampling pipe 38, the fan 33, and the smoke detector 32, and is released from the outlet 37. In this way, the inlets 36 can be distributed to draw outside air from a relatively wide area into the smoke detector 32.

[0024] The smoke detector 3 of Example 4 detects smoke in the airflow AC using the smoke detector 32. The small intake port 36 makes it difficult for dust to enter the air sampling tube 38. However, dust may adhere to the vicinity of the intake port 36, weakening the airflow AC. In the smoke detector 3 of Example 4, the control device 31 sends a signal to the drive circuit 35 to rotate the fan 33 in reverse when a predetermined time has elapsed since the fan 33 was rotated. This state is shown in Figure 6.

[0025] 6 is a cross-sectional view of smoke detector 3 during discharge in Example 4. As fan 33 rotates in the reverse direction, airflow AC is reversed to become reverse airflow BC, and air is discharged from inlet 36. As a result, dust that has adhered to and accumulated on inlet 36 is blown out of inlet 36 and removed. In Example 4, smoke is taken in through inlet 36 and detected, so the time for which fan 33 is rotated in the reverse direction is short enough that it does not interfere with fire detection.

[0026] In the first to fourth embodiments, the fans 13, 23, 33, the motors 14, 24, 34, and the drive circuits 15, 25, 35 are used as suction devices, but other configurations may be used as long as the suction device is capable of sucking in outside air and reversing the airflow AC.

[0027] Furthermore, the specific configuration is not limited to the embodiments, and the present invention includes design changes within the scope of the gist of the present invention. Furthermore, the above-mentioned examples and modifications can be combined by utilizing each other's technology as long as there are no particular contradictions or problems in the purpose, configuration, etc. [Explanation of symbols]

[0028] C Ceiling panel, AC airflow, BC reverse airflow, 1 smoke detector, 11 control device, 12 smoke detector, 121 light-emitting element, 122 light-receiving element, 13 fan, 14 motor, 15 drive circuit, 16 intake port, 17 discharge port, 2 smoke detector, 21 control device, 22 smoke detector, 221 light-emitting element, 222 light-receiving element, 23 fan, 24 motor, 25 drive circuit, 26 intake port, 27 discharge port, 28 pressure sensor, 3 Smoke detector, 31 Control device, 32 Smoke detector, 321 Light-emitting element, 322 Light-receiving element, 33 Fan, 34 Motor, 35 Drive circuit, 36 Inlet port, 37 Outlet port, 38 Air sampling pipe

Claims

1. A suction-type smoke detector having an intake port and a suction device, The suction device draws outside air through the suction port and draws it into the smoke detector, Dust is removed by discharging air out through the intake port. A smoke detector characterized by:

2. A dust detection device is provided, 2. The smoke detector according to claim 1, wherein when the dust detection device detects accumulation of dust at the inlet, air is discharged to the outside from the inlet.

3. 3. The smoke detector according to claim 2, wherein the dust detecting device detects dust when a value obtained by removing high frequency components from the output of the light receiving element becomes equal to or greater than a predetermined value.

4. The smoke detector is provided with a pressure sensor, 3. The smoke detector according to claim 2, wherein the dust detection device detects accumulation of dust by measuring the air pressure generated by the suction device with the pressure sensor.

5. 2. The smoke detector according to claim 1, wherein suction and discharge from said inlet are repeated at predetermined time intervals.

6. The suction device is A smoke detector as described in any one of claims 1 to 5, characterized in that when air is released to the outside from the intake port, it is released at a higher pressure than when outside air is sucked in through the intake port and drawn into the smoke detector.

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