A smoke sensor, a housing and a smoke alarm

Abstract

A smoke sensor, a shell and a smoke alarm, comprising: a shell, the shell comprising a sensor base and a sensor cover arranged oppositely; a transmitting tube and a receiving tube located in the shell; the transmitting tube is used for transmitting a light beam into the shell; the receiving tube is used for receiving the light beam; a first included angle is formed between the center line of the transmitting light beam of the transmitting tube and the sensor base; a second included angle is formed between the center line of the receiving light beam of the receiving tube and the sensor base; the transmitting light beam of the transmitting tube and the receiving light beam of the receiving tube exist an intersection point; the distance between the sensor base and the sensor cover is a sensor height; the distance between the intersection point and the sensor cover can be greater than 24% of the sensor height; the distance between the intersection point and the sensor base can be greater than 24% of the sensor height. The interference of non-smoke particles can be reduced, and the false alarm rate can be reduced.

Description

Technical Field

[0001] This application relates to fire protection equipment, and more specifically, to a smoke sensor, housing, and smoke alarm. Background Technology

[0002] Smoke sensors are a core component in the field of smoke detection, providing fire early warning conditions by detecting the scattering effect of smoke particles on light. A typical smoke sensor includes an infrared emitter, a receiver, and a complex optical channel. When smoke particles enter the smoke sensor, the scattered light is captured by the receiver and triggers an alarm signal. Although this technology has advantages such as high sensitivity and fast response speed, it still suffers from significant false alarm problems in practical applications.

[0003] The primary cause of false alarms is interference from dust, condensation, and other contaminants. The internal channels of smoke sensors are constantly exposed to the environment, allowing dust and condensation particles to gradually accumulate on the inner walls and optical components. These particles are similar in size to smoke particles (typically micrometers), creating a smoke-like scattering effect on the emitted light, causing the receiver to misinterpret it as a fire signal. This is especially true in high-dust environments (such as industrial plants and construction sites) and high-humidity environments, where dust and condensation accumulate rapidly, significantly increasing the frequency of false alarms. While existing technologies mitigate this problem by adding dust filters or regular cleaning, filters reduce smoke entry efficiency, and manual maintenance is costly and difficult to implement in real-time.

[0004] Furthermore, traditional smoke sensors typically employ an open design to accelerate smoke diffusion in order to improve sensitivity, but this further exacerbates the intrusion of dust and moisture. Therefore, how to fundamentally suppress false alarms caused by environmental interference while ensuring detection performance remains a challenge. Utility Model Content

[0005] One objective is to provide a smoke sensor, housing, and smoke alarm that reduces interference from non-smoke particles and lowers the false alarm rate.

[0006] In a first aspect, a smoke sensor includes:

[0007] The housing includes a sensor base and a sensor cover disposed opposite to each other; a transmitting tube and a receiving tube located inside the housing; the transmitting tube is used to emit a light beam into the housing; the receiving tube is used to receive the light beam; the center line of the emitted light beam of the transmitting tube has a first angle with the sensor base; the center line of the received light beam of the receiving tube has a second angle with the sensor base; the emitted light beam of the transmitting tube and the received light beam of the receiving tube have an intersection point; the distance between the sensor base and the sensor cover is the sensor height; the distance between the intersection point and the sensor cover is greater than 24% of the sensor height; the distance between the intersection point and the sensor base is greater than 24% of the sensor height.

[0008] By placing the transmitting and receiving tubes inside the housing and specifying the distance between the intersection point of their beams and the sensor cover and sensor base, the intersection point can be positioned so that it is not too close to the sensor cover or sensor base. This reduces the interference of non-smoke particles attached inside the sensor on the beam and improves the accuracy and sensitivity of the detection.

[0009] The distance between the intersection point and the sensor base can be 24% - 36% of the sensor height.

[0010] By setting the junction point within 24% to 36% of the sensor height, the location of the junction point can be further optimized, which can reduce false alarms and improve the reliability of detection.

[0011] The distance between the intersection point and the sensor base can be 30% of the sensor height.

[0012] Determining the optimal intersection point height allows for the best balance in detection performance, thereby improving the overall system performance.

[0013] The distance between the transmitting tube and the receiving tube can be 31%-47% of the outer diameter of the sensor base.

[0014] By setting the spacing range between the transmitter and receiver tubes, the location of the intersection point can be further defined, and the overall design of the smoke sensor can be optimized. This avoids increased production costs and spatial layout caused by excessive size, while also preventing the reaction area from becoming too narrow due to excessive size, which would weaken the effect of preventing background signal increase caused by condensation, dust, or foreign objects.

[0015] The angle between the centerline of the receiving beam and the centerline of the transmitting beam can be 112°-168°.

[0016] By setting the included angle within this range, the location of the intersection point can be further defined, and the propagation path of the light beam within the maze sensor can be optimized. This ensures that sufficient light flux can be received by the receiving tube, while reducing the background signal received by the receiving tube and lowering false alarms caused by non-smoke particles adhering to the inner wall of the maze sensor.

[0017] The range of the first included angle and the second included angle can be 16°-24°.

[0018] By setting the range of the first and second included angles, the beam angles of the transmitting and receiving tubes can be further optimized, thereby reducing interference from non-smoke particles and improving detection accuracy.

[0019] The transmitting tube may include a first transmitting tube and a second transmitting tube, wherein the centerline of the first transmitting tube and the centerline of the receiving tube form a third angle, and the centerline of the second transmitting tube and the centerline of the receiving tube form a fourth angle; both the third angle and the fourth angle are 155°.

[0020] By setting the angle between the center lines of the first and second transmitting tubes and the center line of the receiving tube to 155°, the multi-optical path design can be optimized, thereby increasing the intensity of the received light signal after the emitted light is reflected by the smoke, thus improving the sensitivity and reliability of the detection.

[0021] The sensor base may be provided with multiple receiving cavities, which are higher than the horizontal plane of the sensor base and are used to accommodate the transmitting tube and the receiving tube.

[0022] By setting the receiving cavity in the above manner, a stable installation position is provided for the transmitting and receiving tubes, thereby reducing optical path deviation caused by vibration or mechanical impact and ensuring the stability and accuracy of the optical path. Since the receiving cavity is higher than the horizontal plane of the sensor base, the interference of non-smoke particles attached to the inner surface of the sensor base on the detection signal can be reduced, thus improving the reliability and stability of the system.

[0023] The accommodating cavity may include a transmitting tube accommodating cavity and a receiving tube accommodating cavity, and the distance between the transmitting tube accommodating cavity and the receiving tube accommodating cavity may be 8%-12% of the outer diameter of the sensor base.

[0024] By setting the spacing range of the receiving cavities, the positional relationship between the transmitting tube receiving cavity and the receiving tube receiving cavity is defined, thereby balancing production costs and spatial layout, while ensuring that the detection area is of moderate width and maintaining good anti-condensation, anti-dust, and anti-foreign matter performance.

[0025] In a second aspect, a smoke sensor housing includes a sensor base and a sensor cover arranged opposite to each other, wherein the distance between the sensor base and the sensor cover is the sensor height; and a transmitter tube receiving cavity and a receiver tube receiving cavity disposed on the sensor base, wherein the receiving cavity is located above the horizontal plane of the sensor base, wherein the receiving cavity is configured such that a first angle is formed between the center line of the transmitter tube emitting a beam in the transmitter tube receiving cavity and the sensor base; and a second angle is formed between the center line of the receiver tube receiving a beam in the receiver tube receiving cavity and the sensor base; the transmitter tube emitting a beam in the transmitter tube receiving cavity and the receiver tube receiving a beam in the receiver tube receiving cavity have an intersection point, the distance between the intersection point and the sensor cover is greater than 24% of the sensor height, and the distance between the intersection point and the sensor base is greater than 24% of the sensor height.

[0026] Thirdly, a smoke alarm includes a circuit board, an alarm device, and the aforementioned smoke sensor connected to the circuit board.

[0027] Applying smoke sensors to smoke alarms ensures that alarms are issued promptly and accurately in the event of a fire.

[0028] By optimizing the location of the detection area, false alarms caused by non-smoke particles such as condensation, dust, insects, and foreign objects entering the detection area can be reduced, thereby lowering the false alarm rate. Attached Figure Description

[0029] The following figures illustrate various non-limiting embodiments.

[0030] Figure 1 This is a schematic diagram of a smoke sensor.

[0031] Figure 2 This is a cross-sectional view of the sensor base;

[0032] Figure 3 A schematic diagram showing the positional relationship between the transmitting tube, the receiving tube, and the junction point;

[0033] Figure 4 This is a schematic diagram of the explosion structure of a smoke sensor;

[0034] Figure 5 This is a top view of the sensor base;

[0035] Figure 6 This is a second top view of the sensor base.

[0036] Icons: 1-Housing; 11-Sensor base; 12-Sensor cover; 13-Receiving cavity; 131-Transmitter tube receiving cavity; 1311-First transmitter tube receiving cavity; 1312-Second transmitter tube receiving cavity; 132-Receiver tube receiving cavity; 2-Transmitter tube; 21-First transmitter tube; 22-Second transmitter tube; 3-Receiver tube; G1-First included angle; G2-Second included angle; G3-Third included angle; G4-Fourth included angle; G5-Fifth included angle. Detailed Implementation

[0037] The embodiments described below are non-limiting examples used to illustrate this application. The components typically described and illustrated in the accompanying drawings can be arranged and designed in a variety of different configurations.

[0038] The terms "inner" and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product is conventionally placed during use. They are used for ease and simplicity of description and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. In addition, the terms "first," "second," etc., are used only to distinguish descriptions and do not indicate or imply relative importance.

[0039] The terms “setup” and “connection” used below are interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components.

[0040] Figure 1 This is a schematic diagram of a smoke sensor. Figure 2 This is a cross-sectional view of the sensor base. Figure 3 This is a schematic diagram showing the positional relationship between the transmitting tube, receiving tube, and junction point. (See also...) Figure 1 , Figure 2 and Figure 3 As shown, the smoke sensor includes: a housing 1, which includes a sensor base 11 and a sensor cover 12 disposed opposite to each other; an emitting tube 2 and a receiving tube 3 located inside the housing 1; the emitting tube 2 is used to emit a light beam into the housing 1; the receiving tube 3 is used to receive the light beam; the center line of the emitted light beam of the emitting tube 2 forms a first angle G1 with the sensor base 11; the center line of the received light beam of the receiving tube 3 forms a second angle G2 with the sensor base 11.

[0041] The emitted beam of the transmitting tube 2 and the received beam of the receiving tube 3 have an intersection point; the distance between the sensor base 11 and the sensor cover 12 limits the sensor height D; the distance between the intersection point and the sensor cover 12 is greater than 24% of the sensor height D; the distance between the intersection point and the sensor base 11 is greater than 24% of the sensor height D.

[0042] Specifically, the sensor cover 12 and the sensor base 11 can cooperate to form a detection area. The sensor cover 12 can cover the sensor base 11, or the sensor base 11 can cover the sensor cover 12, or the two can cooperate with side wall components such as insect screens to form an integral structure.

[0043] like Figure 2 As shown, a transmitting tube 2 and a receiving tube 3 are provided inside the housing 1. Both the transmitting tube 2 and the receiving tube are inclined towards the inside of the housing 1. That is, the center line of the emitted beam of the transmitting tube 2 forms a first angle G1 with the horizontal plane including the sensor base 11, and the center line of the received beam of the receiving tube 3 forms a second angle G2 with the horizontal plane. Thus, the center line of the emitted beam of the transmitting tube 2 is not horizontal, and the center line of the received beam of the receiving tube 3 is also not horizontal.

[0044] The emitting tube 2 emits a light beam into the housing 1. This light beam may be scattered and reflected by smoke particles inside the sensor, and may also be reflected by the inner wall of the housing 1. When there are no smoke particles, the receiving tube 3 primarily receives the light beam emitted by the emitting tube 2 and reflected from the inner wall of the housing 1. When smoke particles are present, the receiving tube 3 receives both the light beam reflected from the inner wall of the housing 1 and the light beam scattered and reflected by the smoke particles. Therefore, based on the magnitude of the signal received by the receiving tube 3, it can be determined whether smoke particles are present inside the sensor.

[0045] The first included angle G1 and the second included angle G2 can be equal in size, ranging from 16° to 24°. When both the first included angle G1 and the second included angle G2 are 20°, the smoke sensor can have the best detection performance and effectively reduce false alarms.

[0046] Condensation typically occurs as liquid water droplets, adhering to the inner walls of the sensor, especially in lower-temperature areas such as the inner surfaces of the sensor base 11 and sensor cover 12. Dust, usually in the form of solid particles, may also adhere to the inner walls of the sensor. These non-smoke particles reflect and scatter light, increasing the background signal received by the receiver tube 3, thereby reducing the relative contribution of smoke particles to the signal strength. When the background signal reaches a certain value, the entry of a small amount of smoke particles or other foreign matter can cause the signal to reach the level required for a fire alarm, thus triggering a false alarm that is not a real fire; or, it may even directly reach the signal level required for a fire alarm, thus triggering a false alarm.

[0047] To optimize the performance of the smoke sensor, particularly to reduce interference from non-smoke particles (such as dust and condensation) on the detection signal, the distance relationship between the junction point and the sensor base 11 and sensor cover 12 can be designed based on the principles disclosed herein. Specifically, the distance between the junction point and the sensor cover 12 is greater than 24% of the sensor height D. Simultaneously, the distance between the junction point and the sensor base 11, i.e., the junction point height A, is also greater than 24% of the sensor height D. This design ensures that the junction point is not too close to the inner surfaces of the sensor cover 12 and the sensor base 11, thereby reducing false alarms caused by the scattering and reflection of light beams by non-smoke particles (such as condensation and dust) adhering to the inner wall of the sensor, and improving the detection accuracy and reliability of the smoke alarm. At the same time, it also ensures the effective propagation and reception of light inside the sensor, thereby improving the detection sensitivity for real fire smoke.

[0048] The distance A between the junction point and the sensor base 11 can be 24%-36% of the sensor height. For example, the distance between the junction point and the sensor base 11 can be 30% of the sensor height.

[0049] It should be noted that the core detection area F is located within a certain range centered on the intersection point. Smoke particles or other foreign objects at the core detection area F will cause more reflection and scattering of the emitted beam. In order to ensure that the distances between the upper edge (the side closer to the sensor cover) and the lower edge (the side closer to the sensor base) of the core detection area and the sensor base 11 are within a reasonable range, and that the detection results are not affected by foreign objects such as dust or condensation accumulated on the sensor base, the distance A between the intersection point and the sensor base 11 can be 24%-36% of the sensor height. Experiments have shown that the accuracy is highest when the distance between the intersection point and the sensor base 11 is 30% of the sensor height.

[0050] In other words, the higher the height of the junction point (i.e., the distance between the junction point and the sensor base 11), the more the core detection area F will move towards the sensor cover 12, resulting in a poorer effect in preventing background signal increments caused by condensation, dust, or other foreign objects at the smoke sensor cover 12. Conversely, the lower the height, the more the core detection area F will move towards the sensor base 11, again resulting in a poorer effect in preventing background signal increments caused by condensation, dust, or other foreign objects at the smoke sensor base 11. Therefore, the core detection area F must consider the impact of condensation, dust, or other foreign objects at both the smoke sensor cover 12 and the smoke sensor base 11 on the background signal. Through experimental testing of the received light signal intensity, the height of the junction point can be reasonably adjusted within the range of 24%-36% of the smoke sensor height D. This optimizes the overall design of the smoke sensor, making it more compact and efficient, reducing false alarms, and improving detection accuracy and reliability. For example, when the sensor height D is 15mm, the optimal height of the junction point can be 4.5mm.

[0051] The angle C between the centerline of the receiving beam and the centerline of the transmitting beam can be between 112° and 168°. If the angle C is too small, the amount of light that can be received by the receiving tube after being reflected and scattered by smoke particles will be relatively less. If the angle C is too large, the background signal received by the receiving tube itself will increase, and the propagation of light inside the sensor will be easily interfered with by non-smoke particles (such as dust, condensation, etc.) attached to the inner wall of the sensor, leading to a further increase in the increase in the background signal and thus causing false alarms. When the angle C is 140°, the anti-condensation, anti-dust, and anti-foreign object effects are optimal.

[0052] Figure 4 This is a schematic diagram of the explosion structure of a smoke sensor, as shown below. Figure 4 As shown, the sensor base 11 is provided with multiple receiving cavities 13. The receiving cavities 13 are higher than the horizontal plane where the sensor base 11 is located, and are used to accommodate the transmitting tube 2 and the receiving tube 3.

[0053] The housing cavity 13 provides a precise mounting position for the transmitting tube 2 and the receiving tube 3, ensuring their stability within the smoke sensor and reducing optical path deviation caused by vibration or mechanical impact, thereby improving the system's reliability and stability. Furthermore, the housing cavity 13 is higher than the horizontal plane of the sensor base 11, reducing interference from non-smoke particles (such as dust and condensation) adhering to the inner surface of the sensor base 11 on the detection signal. Each housing cavity can be set independently, or multiple housing cavities can be designed into a connected integrated structure, forming an integrated transmitting and receiving module.

[0054] For example, the receiving cavity 13 may include a transmitting tube receiving cavity 131 and a receiving tube receiving cavity 132 for accommodating the corresponding transmitting tube 2 and receiving tube 3, and the position of the receiving cavity 13 corresponds to the position of the transmitting tube 2 and the receiving tube 3. Among them, the transmitting tube receiving cavity 131 includes a first transmitting tube receiving cavity 1311 and a second transmitting tube receiving cavity 1312.

[0055] Combination Figure 3 and Figure 4 As shown, the distance H between the transmitting tube cavity 131 and the receiving tube cavity 132 can be 8%-12% of the outer diameter E of the sensor base, for example, 10%. For example, if the outer diameter E of the sensor base can be 50mm, then the optimal value of the distance H between the transmitting tube cavity 131 and the receiving tube cavity 132 can be 5mm.

[0056] Figure 5 This is a top view of the sensor base, combined with... Figure 4 and Figure 5 As shown ( Figure 5 The transmitting tube and receiving tube are set inside the corresponding receiving cavity (not visible in the figure). The distance B between the transmitting tube 2 and the receiving tube 3 can be 31%-47% of the outer diameter E of the sensor base.

[0057] If the spacing B is too large, the outer diameter E of the sensor base will also increase accordingly. This will not only increase the overall size of the product and production costs, but may also affect the spatial layout of the smoke alarm's internal cavity due to the further increase in the size of the smoke sensor.

[0058] If the size of the spacing B is too small, although the size of the outer diameter E of the sensor base can remain unchanged, the detection area inside the smoke sensor will become smaller, and the core detection area F will move towards the sensor base 11. This will also weaken the effect of preventing the background signal from increasing due to condensation, dust or foreign objects.

[0059] Assuming the sensor height D remains constant, and the first included angle G1 and the second included angle G2 remain constant, if the spacing B is too small, the distance between the core detection area F and the sensor base 11 will be too close. If the spacing B is too large, the distance between the core back detection F and the sensor cover 12 will be too close. As a result, dust and other foreign objects accumulated on the sensor cover 12 or the sensor base 11 can more easily cause an increase in the background signal, reducing the accuracy of fire smoke particle concentration detection. Therefore, the spacing B between the transmitting tube 2 and the receiving tube 3 should be controlled within a reasonable range.

[0060] The distance B between the transmitting tube 2 and the receiving tube 3 can be set to 31% - 47% of the outer diameter E of the sensor base, with an optimal value of, for example, 39.2%. The specific ratio can be adjusted according to actual application requirements. For example, when the outer diameter E of the sensor base is 50mm, the distance B between the transmitting tube 2 and the receiving tube 3 can be 19.6mm.

[0061] The height of the intersection point is determined by three variables: the angle C between the transmitting tube 2 and the receiving tube 3, the distance B between the transmitting tube 2 and the receiving tube 3, and the sensor height D. By setting the angle C, the distance B, and the sensor height D, the position of the intersection point can be optimized, increasing its distance from the inner wall of the smoke sensor and reducing interference from non-smoke particles (such as dust, condensation, etc.) on the detection signal.

[0062] In other embodiments, the transmitting tube 2 is an integrated transmitting tube used to emit light of different wavelengths; the receiving tube 3 is a full-spectrum receiving tube used to receive light of different wavelengths.

[0063] The integrated emitter 2 can alternately emit multiple wavelengths of light. For example, it can emit infrared light and blue visible light, or red visible light and infrared light. This multi-wavelength emission capability allows the smoke detector to more comprehensively detect different types of smoke particles because different wavelengths of light have different scattering and absorption characteristics for smoke particles. The full-spectrum receiver 3 can simultaneously detect multiple wavelengths of light emitted from the integrated emitter 2. By receiving light of different wavelengths, the full-spectrum receiver 3 can more accurately analyze the characteristics of smoke particles, thereby improving the accuracy and reliability of detection.

[0064] Figure 6 This is a second top view of the sensor base, as shown below. Figure 4 and Figure 6 As shown, the transmitting tube 2 includes a first transmitting tube 21 and a second transmitting tube 22, and the center lines of the first transmitting tube 21 and the second transmitting tube 22 are symmetrically arranged about the center line of the receiving tube 3.

[0065] like Figure 6 As shown, a third angle G3 is formed between the centerline of the first transmitting tube 21 and the centerline of the receiving tube 3, and a fourth angle G4 is formed between the centerline of the second transmitting tube 22 and the centerline of the receiving tube 3. Both the third and fourth angles can be obtuse angles, ranging from 120° to 160°, with an optimal value, for example, 155°. A fifth angle G5 between the centerlines of the first transmitting tube 21 and the second transmitting tube 22 can be an acute angle. This allows the light beams to intersect at a small angle in space, concentrating the beam, increasing the light intensity in the detection area, and enabling smoke particles to more effectively scatter and reflect light, thereby improving detection sensitivity.

[0066] The first emitting tube 21 can be used to emit red visible light, and the second emitting tube 22 can be used to emit infrared light.

[0067] For example, the first emitting tube 21 can be an R-emitting tube, which emits red visible light, typically with a wavelength range of 620nm-750nm. Red visible light is effective at detecting small particulate smoke (such as smoke from burning paper), providing high detection sensitivity. Furthermore, red visible light has a relatively long wavelength, second only to infrared light in the visible spectrum. In some scenarios, this longer wavelength gives red visible light strong penetrating power, making it less prone to scattering and absorption when encountering smoke particles, allowing it to pass through the smoke more effectively. Therefore, the receiving tube 3 can receive a more stable light signal, thereby improving the accuracy of smoke particle detection. The second emitting tube 22 can be an IR-emitting tube, which emits infrared light, typically with a wavelength range of 750nm-1000nm. Infrared light has high sensitivity to larger smoke particles (such as smoke from burning wood) because its longer wavelength allows it to penetrate smoke particles more effectively. In addition, infrared light has strong resistance to background interference (such as dust, condensation, etc.), thus reducing false alarms. By combining R-emitting diodes (emitting red visible light) and IR-emitting diodes (emitting infrared light) and optimizing the beam propagation path through a specific geometric layout, detection sensitivity and accuracy can be effectively balanced, enabling more comprehensive detection of different types of smoke particles.

[0068] The centerlines of the first transmitting tube 21 and the second transmitting tube 22 can also be asymmetrically arranged with respect to the centerline of the receiving tube 3. The first transmitting tube 21, the second transmitting tube 22, and the receiving tube 3 can be arranged on the same plane or not on the same plane. The centerline of the emitted beam of the first transmitting tube 21 intersects with the centerline of the received beam of the receiving tube 3 to form a first detection area, and the centerline of the emitted beam of the second transmitting tube 22 intersects with the centerline of the received beam of the receiving tube 3 to form a second detection area. The overlapping area of ​​the first detection area and the second detection area is the core detection area F.

[0069] The bottom of the transmitting tube 2 and the receiving tube 3 can also be equipped with an adjustable bracket. The smoke sensor can also include a micro motor and an integrated temperature and humidity sensor, as well as a bracket that can drive the transmitting tube 2 and the receiving tube 3 via the motor. The bracket allows the transmitting tube 2 and the receiving tube 3 to be adjusted in multiple directions. For example, when the humidity is high, the angle, height, and distance between the transmitting tube 2 and the receiving tube 3 can be adjusted to keep the core detection area F away from the inner wall of the sensor and reduce interference from condensation.

[0070] This application also provides a smoke alarm, which includes a circuit board, an alarm device, and a smoke sensor connected to the circuit board. The smoke sensor can be any of the smoke sensors described in the above embodiments.

[0071] An alarm device is used to issue an alarm signal when smoke particles are detected. It may include an audible alarm and / or a visual alarm (such as a flashing LED) to alert the user to the presence of a fire. A circuit board may be electrically connected to the receiver 3 in the smoke sensor. The receiver 3 transmits an electrical signal to the circuit board. The control unit of the circuit board determines whether the electrical signal is greater than a baseline electrical signal (the electrical signal when there is no smoke). If it is greater, it controls the alarm device to issue an alarm signal. In other embodiments, the control unit determines whether the conditions for a fire alarm are met based on multiple electrical signals fed back from the receiver 3. The conditions for a fire alarm may be that the ratio of the electrical signal of red visible light to the electrical signal of infrared light reaches a preset threshold.

[0072] It should be noted that the features in each embodiment can be combined with each other.

[0073] The above are merely non-limiting embodiments of this application. Modifications, equivalent substitutions, and improvements can be made within the scope of the claims.

Claims

1. A smoke sensor, characterized by include: The housing (1) includes a sensor base (11) and a sensor cover (12) disposed opposite to each other, wherein the distance between the sensor base (11) and the sensor cover (12) is the sensor height; The transmitting tube (2) and the receiving tube (3) are located inside the housing (1); The transmitting tube (2) is used to emit a light beam into the housing (1); the receiving tube (3) is used to receive the light beam; The center line of the emitted beam of the emitting tube (2) forms a first angle with the sensor base (11); The center line of the receiving beam of the receiving tube (3) forms a second angle with the sensor base (11); The emitted beam of the transmitting tube (2) and the received beam of the receiving tube (3) intersect at a point; the distance between the intersection point and the sensor cover (12) is greater than 24% of the sensor height; the distance between the intersection point and the sensor base (11) is greater than 24% of the sensor height.

2. The smoke sensor of claim 1, wherein, The distance between the intersection point and the sensor base (11) is 24% - 36% of the sensor height.

3. The smoke sensor of claim 2, wherein, The distance between the intersection point and the sensor base (11) is 30% of the sensor height.

4. The smoke sensor according to claim 2, characterized in that, The distance between the transmitting tube (2) and the receiving tube (3) is 31%-47% of the outer diameter of the sensor base (11).

5. The smoke sensor according to claim 4, characterized in that, The angle between the centerline of the received beam and the centerline of the emitted beam is 112°-168°.

6. The smoke sensor according to claim 1, characterized in that, The values ​​of the first included angle and the second included angle are in the range of 16°-24°.

7. The smoke sensor according to claim 1, characterized in that, The transmitting tube (2) includes a first transmitting tube (21) and a second transmitting tube (22). The center line of the first transmitting tube (21) forms a third angle with the center line of the receiving tube (3), and the center line of the second transmitting tube (22) forms a fourth angle with the center line of the receiving tube (3). Both the third angle and the fourth angle are 155°.

8. The smoke sensor of claim 1, wherein, Also includes: Multiple receiving cavities (13) for accommodating the transmitting tube (2) and the receiving tube (3) are disposed on the sensor base (11), wherein the receiving cavities (13) are higher than the horizontal plane of the sensor base (11).

9. The smoke sensor according to claim 8, characterized in that, The accommodating cavity (13) includes a transmitting tube accommodating cavity (131) and a receiving tube accommodating cavity (132), and the distance between the transmitting tube accommodating cavity (131) and the receiving tube accommodating cavity (132) is 8%-12% of the outer diameter of the sensor base (11).

10. A smoke alarm, characterized in that It includes a circuit board, an alarm device, and a smoke sensor as described in any one of claims 1 to 9, wherein the smoke sensor is connected to the circuit board.

11. A smoke sensor housing characterized by, include: A sensor base (11) and a sensor cover (12) are arranged opposite to each other, wherein the distance between the sensor base (11) and the sensor cover (12) is the sensor height; The receiving cavity (13) includes a transmitting tube receiving cavity (131) and a receiving tube receiving cavity (132), and is disposed on the sensor base (11), wherein the receiving cavity (13) is higher than the horizontal plane of the sensor base (11); The receiving cavity (13) is configured as follows: A first angle is formed between the center line of the beam emitted by the emission tube (2) in the emission tube receiving cavity (131) and the sensor base (11); A second angle is formed between the center line of the receiving tube (3) receiving the light beam in the receiving tube cavity (132) and the sensor base (11); The beam emitted by the transmitting tube (2) in the transmitting tube cavity (131) and the beam received by the receiving tube (3) in the receiving tube cavity (132) have an intersection point; the distance between the intersection point and the sensor cover (12) is greater than 24% of the sensor height; the distance between the intersection point and the sensor base (11) is greater than 24% of the sensor height.

12. The smoke sensor housing of claim 11, wherein, include: The transmitting tube receiving cavity (131) includes a first transmitting tube receiving cavity (1311) and a second transmitting tube receiving cavity (1312), configured to form a third angle between the centerline of the first transmitting tube (21) in the first transmitting tube receiving cavity (1311) and the centerline of the receiving tube (3) in the receiving tube receiving cavity (132), and to form a fourth angle between the centerline of the second transmitting tube (22) in the second transmitting tube receiving cavity (1312) and the centerline of the receiving tube (3) in the receiving tube receiving cavity (132); and both the third angle and the fourth angle are 155°.

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