Smoke detector

Abstract

The application provides a smoke detector, comprising: a shell; a sensing chamber in the shell, the sensing chamber comprising a first light emitter and a first light receiver arranged at the edge of the sensing chamber and facing the middle part of the sensing chamber, wherein the sensing chamber comprises a first baffle arranged near the first light emitter, and the first baffle comprises a baffle main body extending from the edge to the middle part of the sensing chamber and a branch part comprising a plurality of sub-baffles branched from the baffle main body; and a circuit board electrically connected with the first light emitter and the first light receiver respectively. The smoke detector according to the application has simple structure, effectively weakens the background light in the sensing chamber, and ensures the normal work of the smoke detector especially in the case that the volume of the sensing chamber is small.

Description

[0001] This is a divisional application, with its parent application number being 201811383578.4, the international filing date being November 20, 2018, and the invention title being a smoke detector. Technical Field

[0002] This invention relates to the field of fire safety, and more specifically, to a smoke detector for detecting fire conditions. Background Technology

[0003] Smoke detectors, also known as smoke-sensing fire detectors or smoke detectors, are commonly used in buildings to detect smoke generated by fires and thus issue alarm signals. A smoke detector typically includes a sensing chamber containing a light emitter, a light receiver, and a sensing area. When smoke reaches a certain concentration in the sensing area, the intensity of light emitted by the emitter scattered to the receiver reaches a critical value, thereby generating a signal and sending an alarm.

[0004] The cost of a smoke detector depends on the size of its sensing chamber. As the sensing chamber size decreases, the distance between the sensing chamber sidewalls and the light emitter decreases, resulting in stronger background light. This background light can include scattered light emitted by the light emitter as well as light refracted or reflected by the sensing chamber walls. This type of background light, acting as background noise, can hinder the proper functioning of the smoke detector. Summary of the Invention

[0005] The purpose of this invention is to solve or at least alleviate the problems existing in the prior art.

[0006] According to some aspects, a smoke detector is provided, characterized in that it includes: case; The sensing chamber within the housing includes a first light emitter and a first light receiver disposed at the edge of the sensing chamber and facing the center of the sensing chamber. The sensing chamber also includes a first baffle disposed near the first light emitter, and the first baffle includes a baffle body and a branch portion. The baffle body extends from the edge of the sensing chamber toward the center, and the branch portion includes a plurality of sub-baffles branching off from the baffle body. The circuit board is electrically connected to the first optical transmitter and the first optical receiver, respectively.

[0007] Optionally, in the smoke detector, a portion of the sub-baffle extends radially toward the first light emitter.

[0008] Optionally, in the smoke detector, the branch is radiating in cross-section.

[0009] Optionally, in the smoke detector, the sensing chamber is cylindrical.

[0010] Optionally, in the smoke detector, the first light emitter and the first light receiver are arranged at a central angle between 90° and 180°, and a second light emitter is arranged in the sensing chamber, the second light emitter being located between the first light emitter and the first light receiver and at a central angle less than 90 degrees from the first light receiver, wherein the first baffle is located between the first light emitter and the second light emitter, and a portion of the sub-baffle extends radially toward the first light emitter and a portion of the sub-baffle extends radially toward the second light emitter.

[0011] Optionally, in the smoke detector, a second baffle extending from the edge of the sensing chamber toward the center is further arranged between the second light emitter and the first light receiver.

[0012] Optionally, in the smoke detector, a third baffle is also arranged on the outside of the first light receiver, and the inner end of the third baffle extends radially toward the first light receiver.

[0013] Optionally, in the smoke detector, the first light emitter and the first light receiver are spaced apart by a central angle between 90° and 180°, and a second light receiver is arranged in the sensing chamber. The second light receiver is located between the first light emitter and the first light receiver and is spaced apart from the first light emitter by a central angle of less than 90 degrees. The first baffle is located between the first light emitter and the second light receiver.

[0014] Optionally, in the smoke detector, a second baffle extending from the edge of the sensing chamber toward the center is further arranged between the second light receiver and the first light receiver, and a third baffle is further provided on the outside of the first light receiver, the inner end of the third baffle extending radially toward the first light receiver.

[0015] Optionally, in the smoke detector, the distance between the first light emitter and the first light receiver is less than 90 degrees of central angle, and a third baffle is provided on the outer side of the first light receiver, with the inner end of the third baffle extending radially toward the first light receiver.

[0016] Optionally, in the smoke detector, the sensing chamber includes an opening, side walls, and a bottom wall, wherein the side walls of the sensing chamber are toothed.

[0017] Optionally, in the smoke detector, the sensing chamber is assembled from a smoke guide cover, a labyrinth body, and a labyrinth base.

[0018] Optionally, in the smoke detector, the first baffle is fixed to the labyrinth base.

[0019] Optionally, in the smoke detector, the maze base defines a light emitter base and a light receiver base, with the first light emitter and the first light receiver respectively located in the light emitter base and the light receiver base. The pins of the first light emitter and the first light receiver pass through the maze base and are connected to the circuit board. The maze body defines a light emitter cover and a light receiver cover. When the maze body and the maze base are assembled together, the first light emitter is fixed between the light emitter base and the light emitter cover, and the first light receiver is fixed between the light receiver base and the light receiver cover.

[0020] The smoke detector according to the present invention has a simple structure and effectively reduces the background light in the sensing room, especially ensuring the normal operation of the smoke detector when the sensing room volume is small. Attached Figure Description

[0021] The disclosure of this invention will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Furthermore, similar numbers in the drawings are used to denote similar components, wherein: Figure 1 An exploded view of a smoke detector according to an embodiment of the present invention is shown; Figure 2 A perspective view of a maze base in a smoke detector according to an embodiment of the present invention is shown; Figure 3 A perspective view of a labyrinth body in a smoke detector according to an embodiment of the present invention is shown; Figure 4 A layout diagram of the sensing chamber of a smoke detector according to an embodiment of the present invention is shown; Figure 5 A variation of the sensing chamber of a smoke detector according to an embodiment of the present invention is shown; and Figure 6 Another variation of the sensing chamber of a smoke detector according to an embodiment of the present invention is shown. Detailed Implementation

[0022] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0023] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this specification are defined relative to the structures shown in the accompanying drawings. They are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive.

[0024] First refer to Figure 1 An exploded view of a smoke detector according to an embodiment of the present invention is shown.

[0025] In some embodiments, the smoke detector may include: Mounting base 1, which is used to fix the smoke detector to a wall, such as a ceiling; The lower housing 2 and the upper housing 7 can be connected together to form the outer shell of the smoke detector, in which the sensing chamber is located. The upper housing 7 may have a smoke inlet 71 to allow smoke to enter the sensing chamber of the smoke detector. In this specific embodiment, the sensing chamber may be composed of a smoke guide cover 6, a labyrinth body 5, and a labyrinth base 4. The smoke guide cover 6 may have a smoke inlet 61 to guide smoke to the sensing area in the center of the sensing chamber. A first light emitter 81, optionally a second light emitter 82, and a first light receiver 91 are arranged in the sensing chamber. The first light emitter 81 and the second light emitter 82 may be, for example, IRLEDs, while the first light receiver 91 may be, for example, a photodiode. A shield 90 may be provided on the first light receiver 91 to avoid interference. The first light emitter 81, the second light emitter 82, and the first light receiver 91 are arranged at the edge of the sensing chamber and face the sensing area in the center of the sensing chamber; and Circuit board 3 is located outside the sensing room, such as below the maze base 4, and is electrically connected to the first light transmitter 81, the second light transmitter 82, and / or the first light receiver 91. Circuit board 3, for example, supplies power to the first light transmitter 81 and the second light transmitter 82 and receives signals from the first light receiver 91.

[0026] The working principle of this type of smoke detector is that when smoke does not enter the sensing chamber, the optical receiver receives only a small amount of background light (also known as background noise). This background light can be scattered light emitted by the light emitter or reflected light from the inner wall of the sensing chamber. When smoke enters the sensing area of ​​the sensing chamber, the light emitted by the light emitter is refracted by the smoke to the optical receiver, causing the light intensity received by the optical receiver to increase to a critical value. If the optical receiver is a photodiode, it emits a signal when the light intensity increases to the critical value, thereby activating the alarm system, etc.

[0027] As described in the background art, as the volume of the sensing chamber gradually decreases, the background light or background noise in the sensing chamber gradually increases, affecting the normal operation of the smoke detector. The smoke detector according to an embodiment of the present invention provides the following structure to reduce background light. See details... Figure 2 , Figure 3 and Figure 4 The smoke detector according to an embodiment of the present invention further includes: a first baffle 42 in the sensing chamber, the first baffle 42 being arranged near a first light emitter 81 located in a light emitter seat 47, and the first baffle 42 including a baffle body 421 extending from the edge of the sensing chamber toward the center and a branch 422 extending from the baffle body 421, the branch 422 including a plurality of branched sub-baffles 4221, 4222, 4223, 4224. In the illustrated embodiment, the branch 422 may be divergent in cross-section, resembling the shape of a hand, and includes four sub-baffles 4221, 4222, 4223, 4224. In alternative embodiments, the branch 422 may have other shapes and may have different numbers of sub-baffles, such as two, three, or five. The unique structure of the first baffle 42 effectively reduces the scattering portion of the light emitted from the light emitter 81 and the reflected light from the sidewalls, thereby effectively reducing the background light in the sensing chamber.

[0028] In some embodiments, a portion of the sub-baffle is tilted or deflected toward the first light emitter 81, or extended radially toward the first light emitter 81. Figures 2 to 4 In the illustrated embodiment, sub-baffles 4223 and 4224 extend radially toward the first light emitter 81, and sub-baffle 4221 extends radially toward the second light emitter 82, thereby effectively blocking the scattering portion of the light emitted by the first light emitter 81 and the second light emitter 82. On the other hand, sub-baffles 4221, 4222, 4223, and 4224 do not block the main light path, and therefore do not affect the normal operation of the smoke detector.

[0029] refer to Figure 2 and Figure 3In some embodiments, the sensing chamber may include an opening, side walls, and a bottom wall. In the illustrated embodiment, the opening of the sensing chamber is formed by the smoke inlet 61 of the smoke guide cover 6, the side walls of the sensing chamber are formed by the side walls 51 of the labyrinth body 5, and the bottom wall of the sensing chamber is formed by the bottom wall 41 of the labyrinth base 4. In some embodiments, the sensing chamber is substantially cylindrical; alternatively, the sensing chamber may have other suitable shapes. In some embodiments, the side walls of the sensing chamber, i.e., the side walls 51 of the labyrinth body 5, are serrated to effectively suppress the reflection of light through the side walls, thereby further reducing background light. In some embodiments, as shown, the first baffle 42 and optional second baffles 43 and third baffles 44 are all fixed to the labyrinth base 4; alternatively, these baffles may extend from the side walls of the labyrinth body or from the smoke guide cover. In some embodiments, the maze base 4 defines light emitter holders 47, 48 and light receiver holder 49, with a first light emitter 81, a second light emitter 82, and a first light receiver 91 located in the light emitter holders 47, 48 and the light receiver holder 49, respectively. The pins of the first light emitter 81, the second light emitter 82, and the first light receiver 91 pass through the maze base 4 and are connected to the circuit board 3. The maze body 5 defines light emitter covers 57, 58 and light receiver cover 59. When the maze body 5 and the maze base 4 are assembled together, the first light emitter 81 is fixed between the light emitter holder 47 and the light emitter cover 57, the second light emitter 82 is fixed between the light emitter holder 48 and the light emitter cover 58, and the first light receiver 91 is fixed between the light receiver holder 49 and the light receiver cover 59.

[0030] For details, please refer to the following: Figure 4 In this embodiment, a first light emitter 81 and a first light receiver 91 are arranged at a central angle b between 90° and 180°. A second light emitter 82 is arranged in the sensing chamber, located between the first light emitter 81 and the first light receiver 91 and at a central angle a between them that is less than 90 degrees. A first baffle 42 is located between the first light emitter 81 and the second light emitter 82. A portion 4223, 4224 of the sub-baffle extends radially toward the first light emitter 81, and a portion 4221 of the sub-baffle extends radially toward the second light emitter 82. In some embodiments, a second baffle 43 extending from the edge of the sensing chamber toward the center is also arranged between the second light emitter 82 and the first light receiver 91. The second baffle 43 blocks part of the background light. In some embodiments, a third baffle 44 is also provided on the outer side of the first light receiver 91, with its inner end extending radially toward the first light receiver 91. The third baffle 44 further reduces the background light that may illuminate the first light receiver 91.

[0031] Continue to refer to Figure 5This illustration shows a variation of the sensing chamber according to the invention. In this embodiment, the sensing chamber includes a first transmitter 81' and a first receiver 91'. In this embodiment, a first baffle 42' may include a sub-baffle extending radially toward the first transmitter 81'. In some embodiments, the first transmitter 81' and the first receiver 91' may be spaced apart by a central angle b of 90 to 180 degrees. In an alternative embodiment shown by dashed lines, the first transmitter 81' and the first receiver 91' (shown by dashed lines) may be spaced apart by a central angle α within 90 degrees. Similarly, in some embodiments, a third baffle 44' may be provided outside the first light receiver 91', with the inner end of the third baffle 44' extending radially toward the first light receiver 91'.

[0032] Continue to refer to Figure 6 This illustration shows a variation of the sensing chamber according to the invention. In this embodiment, a central angle b between a first light emitter 81'' and a first light receiver 91'' is spaced between 90° and 180°. A second light receiver 92'' is arranged in the sensing chamber, located between the first light emitter 81'' and the first light receiver 91'' and spaced from the first light emitter 81'' by a central angle a of less than 90 degrees. A first baffle 42'' is located between the first light emitter 81'' and the second light receiver 92''. In some embodiments, a second baffle 43'' extending from the edge of the sensing chamber towards the center is further arranged between the second light receiver 92'' and the first light receiver 91''. A third baffle 44'' is also provided on the outer side of the first light receiver 91'', with its inner end extending radially toward the first light receiver 91''.

[0033] The specific embodiments described above are merely for the purpose of more clearly illustrating the principles of the present invention, wherein the various components are clearly shown or described to make the principles of the present invention easier to understand. Various modifications or variations can be readily made to the present invention by those skilled in the art without departing from the scope of the invention. Therefore, it should be understood that all such modifications or variations should be included within the patent protection scope of the present invention.

Claims

1. A smoke detector, characterized in that, include: case; The housing contains a sensing chamber, which includes a first light emitter and a first light receiver arranged at the edge of the sensing chamber and facing the center of the sensing chamber. The first light emitter and the first light receiver are arranged at a central angle between 90° and 180°. The sensing chamber includes a first baffle, which is arranged near the first light emitter. The first baffle includes a baffle body and a branch, the baffle body extending from the edge of the sensing chamber toward the center, and the branch including a plurality of sub-baffles branching off from the baffle body. A second light emitter is arranged in the sensing chamber, the second light emitter is located between the first light emitter and the first light receiver and is spaced from the first light receiver by a central angle of less than 90 degrees, wherein the first baffle is located between the first light emitter and the second light emitter; A second baffle extending from the edge of the sensing chamber toward the center is arranged between the second light emitter and the first light receiver. The second baffle blocks a portion of the background light, which includes a portion of the light emitted by the second light emitter that would otherwise be incident on the first light receiver. A third baffle is disposed outside the first optical receiver, the inner end of the third baffle extending radially toward the first optical receiver; and The circuit board is electrically connected to the first optical transmitter and the first optical receiver, respectively.

2. The smoke detector according to claim 1, characterized in that, A portion of the sub-baffle extends radially toward the first light emitter.

3. The smoke detector according to claim 1, characterized in that, The branch is radiating in cross-section.

4. The smoke detector according to claim 1, characterized in that, The sensing chamber is cylindrical.

5. The smoke detector according to claim 1, characterized in that, A portion of the sub-baffle extends radially toward the first light emitter and a portion of the sub-baffle extends radially toward the second light emitter.

6. The smoke detector according to claim 1, characterized in that, The sensing chamber includes an opening, side walls, and a bottom wall, and the side walls of the sensing chamber are toothed.

7. The smoke detector according to claim 1, characterized in that, The sensing chamber is assembled from a smoke guide cover, a labyrinth body, and a labyrinth base.

8. The smoke detector according to claim 7, characterized in that, The first baffle is fixed to the maze base.

9. The smoke detector according to claim 7, characterized in that, The maze base defines a light transmitter base and a light receiver base, with the first light transmitter and the first light receiver respectively located in the light transmitter base and the light receiver base. The pins of the first light transmitter and the first light receiver pass through the maze base and are connected to the circuit board. The maze body defines a light transmitter cover and a light receiver cover. When the maze body and the maze base are assembled together, the first light transmitter is fixed between the light transmitter base and the light transmitter cover, and the first light receiver is fixed between the light receiver base and the light receiver cover.

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