CN109427170B

CN109427170B - Smoke detector

Info

Publication number: CN109427170B
Application number: CN201710773232.4A
Authority: CN
Inventors: 宋龙; 徐奂; 黄康; 罗京宜; 任利
Original assignee: Siemens Schweiz AG
Current assignee: Siemens Schweiz AG
Priority date: 2017-08-31
Filing date: 2017-08-31
Publication date: 2021-08-06
Anticipated expiration: 2037-08-31
Also published as: CN109427170A

Abstract

The embodiment of the invention discloses a smoke detector, which comprises a first light guide cover (310) and a second light guide cover (320) which are respectively used for accommodating a light emitting element (120) and a light receiving element (130), wherein each light guide cover is respectively provided with a light transmission window (311, 321), an included angle beta between two optical axes of the light emitting element (120) arranged in the first light guide cover (310) and the light receiving element (130) arranged in the second light guide cover (320) is smaller than 90 degrees, and the two light transmission windows are positioned in the same plane which is vertical to the plane of the two optical axes. The scheme of the invention can effectively eliminate or weaken useless stray light, thereby improving the detection sensitivity.

Description

Smoke detector

Technical Field

The present invention relates generally to Smoke detectors (Smoke detectors) in fire protection systems, and more particularly to a scattering type photoelectric Smoke Detector in fire protection systems.

Background

A scattering type photoelectric smoke detector is detection equipment commonly used in the field of fire fighting. The scattering type photoelectric smoke detector detects a fire by using scattering of detection light by particles in gas. There are also other types of scattered-radiation photoelectric smoke detectors and other types of scattered-radiation photoelectric smoke detector-based composite detectors that incorporate temperature sensors in the market.

It is generally desirable for smoke detectors to have a high sensitivity so that they can report a fire early enough to prompt the field personnel to evacuate in time. The minimum response threshold Th of the photoelectric smoke detector is not less than 0.05dB/m, which is regulated in the existing national standard GB 4715-2005. The threshold value is a numerical value of attenuation degree of the smoke to light emitted by a standard light source at the time when the photoelectric smoke detector is tested to test the performance, the test smoke is added into a test smoke box at a certain concentration increasing rate, and the detector alarms. The threshold Th reflects the smoke concentration at the alarm time of the detector, and the smaller the alarm threshold, the lower the smoke concentration at the alarm time, that is, the higher the sensitivity of the smoke detector.

Figure 1 schematically illustrates a schematic diagram of a typical photoelectric smoke detector. Photoelectric smoke detectors are typically mounted on the roof of a room in an inverted position. Fig. 1 is a bottom view of the internal structure of a rooftop mounted photoelectric smoke detector 100. The photoelectric smoke detector 100 is a forward scattering type photoelectric smoke detector that enters smoke from the side of the detection cavity. As shown in fig. 1, the photoelectric smoke detector 100 includes a detection chamber 110, a light emitting element 120, and a light receiving element 130. The light emitting element 120 is, for example, an infrared light emitting diode or a light emitting diode of other wavelength bands. The light receiving element 130 is, for example, a photodiode or other light sensing element. The side of the detection cavity 110 is provided with a smoke inlet. Through which opening particles 10 floating at and near the location of the photoelectric smoke detector may enter the detection chamber 110. Here, in the event of a fire, the particles 10 comprise combustion-generated aerosols (aerosol) composed of multiphase materials, which generally include gaseous combustion products from the pyrolysis or combustion of combustible materials, entrained volumes of air, incompletely combusted liquids, solid phase decomposition products, and minute particles. Such gases and particles in the event of a fire may also be referred to collectively as fire smoke or fire smoke, wherein the particles in the fire smoke have a significant light scattering effect.

In fig. 1, the angle α between the light emitting element 120 and the light receiving element 130 is greater than 90 ° and less than 180 °. The outgoing light 20 from the light emitting element 120 is scattered by the particles in the detection chamber 110, and the scattered light 30 therein is incident on the light receiving element 130. As can be seen, the angle between the scattered light 30 and the outgoing light 20 is also substantially α >90 °, a structure referred to as forward scattering structure.

The scattering type photoelectric smoke detector in the current Chinese market is easy to generate false fire alarm under smaller disturbance because of higher sensitivity setting. For this reason, the fire protection field management agency in china recently proposed: a modest increase in the minimum response threshold is required, for example by substantially an order of magnitude. If the minimum response threshold is raised to about 0.2-0.4 dB/m, the single-pure forward scattering type photoelectric smoke detector as shown in FIG. 1 can hardly meet all the test requirements of the national standard.

In order to solve the above problems, a back scattering type photoelectric smoke detector is also proposed in the art, as shown in fig. 2. Unlike the photoelectric smoke detector of fig. 1, in the photoelectric smoke detector 200 shown in fig. 2, the included angle β between the light emitting element 120 and the light receiving element 130 is less than 90 °. The outgoing light 20 from the light emitting element 120 is scattered by the particles in the detection cavity 110, and the scattered light 40 therein is incident on the light receiving element 130. The scattered light 40 travels substantially in the opposite direction to the outgoing light 20 and also makes an angle β with the outgoing light 20 of less than 90 °. For this reason, the scattered light 40 is referred to as backward (back) scattered light. The structure shown in fig. 2 is also referred to as a backscatter structure. Backscattering has higher sensitivity to certain smoke than forward scattering, but generally the signal intensity of the backscattering is relatively weak, and the requirement on the signal-to-noise ratio is higher, and for this reason, an optical structure (also called a labyrinth structure) with good extinction effect needs to be arranged in the backscattering type smoke detector to absorb or eliminate stray light and simultaneously improve the signal intensity of the scattered light.

Disclosure of Invention

In view of this, the embodiment of the present invention provides a smoke detector, which can have a relatively high minimum response threshold for smoke detection.

The smoke detector provided in this embodiment includes a detection cavity into which particles floating near the smoke detector can enter, at least one light emitting element and one light receiving element disposed in the detection cavity, wherein the smoke detector further includes:

the first light guide cover is positioned in the detection cavity and provided with a first light-transmitting window, and the first light guide cover is suitable for accommodating a first light-emitting element so that emergent light rays of the first light-emitting element can pass through the first light-transmitting window and are projected to particles in the detection cavity;

a second light guide cover which is positioned in the detection cavity and is provided with a second light-transmitting window, wherein the second light guide cover is suitable for accommodating the light receiving element so that the light receiving element can receive light rays which are transmitted through the second light-transmitting window;

wherein the first light-transmitting window and the second light-transmitting window are positioned in the same plane, and

an included angle beta between two optical axes of the light emitting element arranged in the first light guide cover and the light receiving element arranged in the second light guide cover is smaller than 90 degrees, and the plane where the two optical axes are located is perpendicular to the plane where the first light transmission window and the second light transmission window are located together.

Therefore, in the embodiment of the invention, by arranging the light guide cover of the light emitting element and the light guide cover of the light receiving element, useful light can be guided, the intensity of the useful light can be enhanced, and useless stray light can be shielded and eliminated. And, through making the light trap that holds the light guide of the light emitting component that corresponds the backward scattering and light receiving element be located the coplanar, can avoid the light that light emitting component sent out directly to enter into light receiving element's receiving face through two light traps to the light that can avoid not having behind the smog granule scattering gets into light receiving element's receiving face and disturbs the detection result.

In one embodiment, a sum of a distance a from a point of intersection of two optical axes of the first light emitting element disposed in the first light guide housing and the light receiving element disposed in the second light guide housing to a light emitting surface of the light emitting element in the first light guide housing and a distance b from the point of intersection of the optical axes to a light receiving surface of the light receiving element disposed in the second light guide housing is less than 36mm, preferably less than 32 mm. Therefore, the total distance from the emitting light to the back scattering is limited in a better range, so that the detection sensitivity of the smoke detector and the light intensity of the detection area can be improved.

In one embodiment, an intersection point of optical axes of the first light emitting element disposed in the first light guide housing and the light receiving element disposed in the second light guide housing is shifted toward the first light guide housing and the second light guide housing side than a geometric center point of the detection chamber, and more preferably, the shift distance h is greater than 4 mm. Therefore, the light background value can be reduced, the directivity of the detector can be improved, and the detection sensitivity of the smoke detector can be further improved.

In one embodiment, the included angle β between the two optical axes of the first light emitting element disposed in the first light guide cover and the light receiving element disposed in the second light guide cover is 50 ° to 70 °, and β is preferably 60 °. β is an angle range of 50 ° to 70 ° which is the optimum detection sensitivity for smoke. And the optical axis included angle structure is easy to arrange, namely, the interference among all parts can be ensured while the structure is compact.

More preferably, an included angle ω between an optical axis of the light receiving element disposed in the second light guide cover and a plane where the second light transmission window is located is 55 ° to 65 °; an included angle theta between the optical axis of the first light-emitting element and the plane where the first light-transmitting window is located is 180 degrees-beta-omega, wherein beta represents the included angle between the two optical axes, and omega represents the included angle between the optical axis of the light-receiving element arranged in the second light guide cover and the plane where the second light-transmitting window is located. The structural design in this embodiment can also reduce stray light entering the second light guide cover, and can increase the intensity of scattered light entering the second light guide cover.

In one embodiment, the smoke detector further comprises a shielding cover covering at least a top portion of the second light guide cover to prevent light from entering the light receiving element from the top portion of the second light guide cover.

In one embodiment, a first light extinction structure is disposed on a side surface of the first light guide cover corresponding to the light emitting channel of the first light emitting element, and/or a second light extinction structure is disposed on a side surface of the second light guide cover corresponding to the light receiving channel of the light receiving element. The provision of a light-extinction structure within the light channel can absorb or reduce unwanted or stray light impinging on the side walls of the light channel. Preferably, the light-extinction structure has a serrated surface. This structure allows light rays striking the sides of the light tunnel to be eliminated or reduced by multiple reflections.

In one embodiment, the detection chamber further comprises an intracavity extinction structure disposed within a circumferential region of the detection chamber facing the first and second light guides. The intracavity extinction structure can absorb and eliminate light rays irradiated on the wall of the detection cavity by the light-emitting element, and prevents the light rays from directly reflecting to enter the receiving surface of the light-receiving element, so that stray light entering the receiving surface of the light-receiving element can be further eliminated.

The intracavity extinction structure comprises a plurality of bending rib plates which extend along the radial direction and are arranged along the circumferential direction, and the orientation of the bending rib plates changes along with the position. The structure design can reflect, absorb and eliminate the light irradiated on the detection cavity wall by the light-emitting element for multiple times.

In one embodiment, the smoke detector further comprises a labyrinth cover, a rib plate extending towards the detection cavity is arranged on one surface of the labyrinth cover facing the detection cavity, the rib plate is bent towards one side of the first light guide cover and one side of the second light guide cover, and preferably the rib plate is V-shaped. This structural design can lead to the cigarette/air current that gets into the detection chamber to make the cigarette flow direction as early as possible detect the region, thereby improve the granule efficiency that gets into the detection chamber, improve the detectivity of cigarette sensor.

In one embodiment, a ratio of a distance f from a light emitting surface of the first light emitting element disposed in the first light guide cover to the first light transmission window to an area of the first light transmission window is 1 to 1.1; and/or the ratio of the distance e from the light receiving surface of the light receiving element placed in the second light guide cover to the second light transmission window to the area of the second light transmission window is 0.4 to 0.5 or about 1. This structural design can further improve the detectivity of smoke detector and the regional light intensity of detection to the stray light that reducible entering second leaded light cover.

In one embodiment, the smoke detector further comprises: a third light guide cover which is positioned in the detection cavity and is provided with a third light-transmitting window, wherein the third light guide cover is suitable for accommodating or mounting a second light-emitting element so that an included angle alpha between the second light-emitting element and the light-receiving element arranged in the second light guide cover is larger than 90 degrees; and the second light-emitting element can project light to the particles in the detection cavity through the third light-transmitting window. Through setting up the first guide cover that can hold or install first light emitting component and the third guide cover that can hold or install second light emitting component, can realize the smoke detector of forward scattering + backscattering to can improve the detectivity of smoke detector and the light intensity of detection zone.

In one embodiment, the sum of the distance c from the intersection of the optical axes of the second light emitting element disposed in the third light guide housing and the light receiving element disposed in the second light guide housing to the light emitting surface of the second light emitting element, plus the distance d from the intersection of the optical axes to the light receiving surface of the light receiving element disposed in the second light guide housing is less than 49 mm. It can be seen that, since the total distance from the emitting light of the second light emitting element to the back scattering is also limited to a better range, the detection sensitivity of the smoke detector and the light intensity of the detection area can be improved.

In one embodiment, an included angle η between an optical axis of the second light emitting element disposed in the third light guide cover and a plane where the third light transmission window is located is 50 ° to 90 °, and more preferably 50 ° to 70 °; the structural design can also reduce stray light entering the second light guide cover and can increase the intensity of scattered light entering the second light guide cover.

The ratio of the distance g from the light emitting surface of the second light emitting element in the third light guide cover to the third light transmission window to the area of the third light transmission window is 1-1.1. The structure design can further improve the detection sensitivity of the smoke detector and the light intensity of the detection area, and can reduce stray light entering the second light guide cover.

In one embodiment, the first light guide cover further has a light shielding protrusion disposed between the first light transmissive window and the second light transmissive window to prevent light emitted from the first light transmissive window from directly entering the second light transmissive window, thereby further reducing stray light entering the receiving surface of the light receiving element.

In one embodiment, the third light guide cover is provided with a first light shielding extension portion on a side of the third light transmission window close to the second light transmission window, and the first light shielding extension portion is configured to prevent light projected from the third light transmission window from directly entering the second light transmission window, so as to further reduce stray light entering the receiving surface of the light receiving element.

In one embodiment, an edge point of the third light-transmitting window, which is far away from the light-receiving element, a top end of the first light-shielding extension portion, and an edge point of the second light-transmitting window, which is far away from the second light-emitting element, are located on the same straight line. The structural design can prevent light projected from the third light-transmitting window from directly entering the second light-transmitting window, so that stray light entering a receiving surface of the light receiving element is further reduced.

In one embodiment, the second light extinction structure of the second light guide cover has a light trap portion located in a region close to the second light transmission window and close to the second light emitting element, and the light trap portion has at least one recess, and the depth of the recess is greater than other portions of the second light extinction structure. The light emitted by the second light-emitting element can be further reflected by the side wall of the detection cavity and then passes through the second light-transmitting window to irradiate the light at the side wall of the channel for reflection elimination, so that the light interference of the light-receiving element in the second light guide cover is avoided.

In one embodiment, the smoke detector is a top-in smoke detector. This kind of structure makes in the granule passes in and out the detector very easily through the top of smoke detector, and can not carry out the gathering in the labyrinth and add up (for example deposition) to reduce the dust and to surveying local influence, and the top mode of advancing cigarette has better directionality with the side mode of advancing cigarette.

In one embodiment, the first light emitting element and/or the second light emitting element is a dual band light emitting element. The application can fully utilize different wavelengths to have different sensitivities to smoke scattering, so that the smoke detection performance and accuracy of the detector are improved, and the overall performance of the smoke detector is further improved.

In one embodiment, the first light guide cover and the second light guide cover are an integral molding. The design structure is simple, the processing is easy, and the installation procedures are reduced.

Drawings

The foregoing and other features and advantages of the invention will become more apparent to those skilled in the art to which the invention relates upon consideration of the following detailed description of a preferred embodiment of the invention with reference to the accompanying drawings, in which:

fig. 1 shows a schematic structure of a conventional forward scattering type smoke detector.

Fig. 2 shows a schematic structure of a conventional backscatter-type smoke detector.

Fig. 3 to 17 are schematic structural diagrams of a smoke detector according to an embodiment of the present invention. Wherein:

FIG. 3 is a schematic view of an embodiment of the smoke detector assembly;

FIG. 4 is a schematic view of the arrangement of light assemblies in the detection chamber shown in FIG. 3;

FIG. 5 is a schematic view of an included angle of light assemblies installed in the first and second light guide covers shown in FIG. 3; FIGS. 6A and 6B are schematic structural views of a first light guide cover and a second light guide cover according to an embodiment;

FIG. 7 is a schematic view of an installation position of a shadow mask according to an embodiment;

FIG. 8 is a schematic distance diagram of an intersection of an optical axis and an optical assembly in one embodiment;

FIG. 9 is a schematic view of the position of the light transmissive window and the light assembly according to one embodiment;

FIG. 10 is a schematic view of the dimensions of a first light transmissive window and a second light transmissive window in one embodiment;

FIG. 11 is a schematic view of a detection zone in one embodiment;

FIG. 12 is a schematic view of the position of a first light guide and a second light guide in a labyrinth according to one embodiment;

FIGS. 13A and 13B are partial schematic views of a labyrinth in accordance with an embodiment;

FIG. 14 is a schematic view of the position of the smoke detector when mounted to the top of a space such as a ceiling in one embodiment;

FIG. 15 is a partial cross-sectional view of a smoke detector in accordance with one embodiment;

FIGS. 16A and 16B are schematic views illustrating a structure of a labyrinth cover according to an embodiment;

FIG. 16C is a schematic diagram illustrating a relative position relationship between a rib plate on the labyrinth cover and the first light guide cover and the second light guide cover in the embodiment;

fig. 17 is a schematic view of light emission of a dual band light emitting element in one embodiment.

Fig. 18 to 30 are schematic structural views of another smoke detector in the embodiment of the present invention. Wherein:

FIG. 18 is a schematic view of an embodiment of the smoke detector assembly;

FIG. 19 is a schematic view of the position of the light assembly shown in FIG. 18 in the plane of the light assembly;

FIG. 20 is a schematic view of the included angles of the light assemblies mounted in the first, second and third light guides of FIG. 18;

FIGS. 21A and 21B are schematic structural views of first to third light guide covers according to an embodiment;

FIG. 22 is a schematic distance diagram of an intersection of an optical axis and an optical assembly in one embodiment;

FIG. 23 is a schematic view of the position of the light transmissive window and the light assembly according to one embodiment;

FIG. 24 is a schematic illustration of dimensions of a first light transmissive window, a third light transmissive window, and a second light transmissive window, in accordance with an embodiment;

FIG. 25 is a schematic view of a detection zone in one embodiment;

FIG. 26 is a schematic view of the positions of a first light guide, a third light guide, and a second light guide in a labyrinth according to one embodiment;

FIGS. 27 and 28 are partial schematic views of a labyrinth in accordance with one embodiment;

FIG. 29 is a schematic view of an installation position of an indicator light according to an embodiment;

fig. 30 is a schematic view of light emission when the second light-emitting element is a dual-band light-emitting element in one embodiment.

Wherein the reference numbers are as follows:

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail by referring to the following examples.

"exemplary" means "serving as an example, instance, or illustration" herein, and any illustration, embodiment, or steps described as "exemplary" herein should not be construed as a preferred or advantageous alternative.

For the sake of simplicity, the drawings only schematically show the parts relevant to the present invention, and they do not represent the actual structure as a product. In addition, for simplicity and clarity of understanding, only one of the components having the same structure or function is schematically illustrated or labeled in some of the drawings.

In this document, "one" means not only "only one" but also a case of "more than one". In addition, herein, "first", "second", and the like are used only for distinguishing one from another, and do not indicate their importance, order, and the like.

In order to enhance the intensity of scattered light scattered by smoke particles in the detection chamber and finally incident on the light receiving element and absorb or eliminate the stray light, the inventors of the present invention considered that in the detection chamber of a smoke sensor having at least one light emitting element and one light receiving element, a light guide cover of the light emitting element and a light guide cover of the light receiving element are provided for guiding and enhancing the intensity of useful light, blocking and eliminating unnecessary stray light, and the like. The smoke detector in the present invention may be of a back scattering type, a forward scattering type, or a front and back scattering type.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail by referring to the following examples. Like reference symbols in the various drawings indicate components that are identical or similar in structure, but that perform the same function. For simplicity, reference to a "smoke detector" in the following text is to be taken as a fire detection means that detects the amount of light scattered by fire smoke, i.e. a detector that detects fire smoke at least partially based on photoelectric means.

The first class of embodiments: back scattering

Fig. 3 to 17 are schematic structural diagrams of a smoke detector according to an embodiment of the present invention. FIG. 3 is a schematic view of an embodiment of the assembly of the smoke detector. As shown in fig. 3, the smoke detector 300 may include: a light emitting element 120, a light receiving element 130, a first light guide cover 310, a second light guide cover 320, a labyrinth piece 340, a labyrinth cover 350.

In the example of fig. 3, the smoke detector 300 further includes a top cover 372 and a bottom cover 374 that snap together to provide protection for the detector 300. The detector 300 also includes a circuit board 380, which is positioned on the bottom surface of the labyrinth 340 (the surface opposite the surface on which the light guides 310, 320 are positioned) when assembled, to provide a circuit portion for the smoke detector. The detector 300 may also include a light guide 360 mounted to the labyrinth 340 for directing light from an alarm indicator (not shown) on the circuit board to the top cover 372 for visibility by a user.

In the smoke detector shown in fig. 3, the labyrinth 340 and the labyrinth cover 350 are assembled (e.g., fastened to each other) to form a detection chamber 110 therebetween. In the example of fig. 3, the smoke detector 300 is in a horizontal or horizontal smoke detection mode. Specifically, as shown in the simplified schematic diagram of fig. 4, the plane formed by the optical axis of the light emitting element 120 and the optical axis of the light receiving element 130 respectively disposed in the first and second light guiding covers is parallel to the plane of the bottom plate 341 of the labyrinth 340.

The detection chamber 110 is configured to enable smoke particles floating in the vicinity of the smoke detector to enter the labyrinth detection chamber 110. In the present invention, smoke preferably enters the detection chamber from the top of the detection chamber 110, i.e., through the labyrinth cover.

FIG. 5 is a schematic diagram of the included angle between the optical axes of the optical components installed in the first and second light guide covers shown in FIG. 3. The light emitting element 120 is adapted to be received within the first light guide housing 310 and the light receiving element 130 is adapted to be received within the second light guide housing 320. As shown in fig. 5, the included angle β between the optical axes of the light emitting element 120 and the light receiving element 130 disposed in the light guide cover is smaller than 90 °, i.e., the light emitting element and the light receiving element form a back scattering structure as shown in fig. 2. Specifically, in order to increase the intensity of the scattered light finally incident on the light receiving element 130, the first and second light guiding covers may be preferably positioned such that the optical axis angle β of the light emitting element 120 and the light receiving element 130 placed therein is 50 ° to 70 °, and more preferably about β to 60 °. β is an angle range of 50 ° to 70 ° in which the detection sensitivity for smoke is optimal. And, the optical axis included angle structure is easy to arrange, namely, the compact structure is ensured, and meanwhile, the interference among all parts is avoided. .

Fig. 6A and 6B are schematic structural diagrams of a first light guide cover 310 and a second light guide cover 320 according to an embodiment. As shown in fig. 6A and 6B, the first light guide cover 310 has a first light-transmitting window 311 and a light-emitting channel 312, and the first light guide cover 310 is disposed in the detection cavity 110 and is adapted to accommodate or mount the light-emitting element 120, and enable the emergent light of the light-emitting element 120 to pass through the light-emitting channel 312 and the first light-transmitting window 311 and be projected into the detection cavity 110.

The second light guide 320 has a second light-transmitting window 321 and a light-receiving channel 322, and the second light guide 320 is also disposed in the detection chamber 110 and is adapted to receive or mount the light-receiving element 130, and enable the light-receiving element 130 to receive scattered light from the detection chamber 110, and the scattered light can be incident on the light-receiving surface of the light-receiving element 130 through the second light-transmitting window 321 and the light-receiving channel 322.

In the present embodiment, as shown in fig. 6A and 6B, the first light-transmitting window 311 and the second light-transmitting window 321 are located in the same plane, i.e., in a plane perpendicular to the optical axes of the light-emitting device 120 and the light-receiving device 130. Thus, the light emitted from the first light-transmitting window 311 by the light-emitting element 120 does not directly enter the receiving surface of the light-receiving element 130 through the second light-transmitting window 321, so that the interference of the light which is not scattered by smoke particles entering the receiving surface of the light-receiving element 130 on the detection result can be avoided, and the shielding of useless stray light is realized. Further, preferably, a light shielding protrusion (not shown) may be further disposed on the first light guide cover 310 and disposed between the first light transmissive window 311 and the second light transmissive window 321, so as to further prevent the light emitted from the first light transmissive window 311 from directly entering the second light transmissive window 321.

As shown in fig. 6B, in one embodiment, a first light extinction structure 313 is disposed on at least one side of the first light guide cover 310 corresponding to the light emitting channel 312 of the light emitting element 120. At least one side of the second light guide cover 320 corresponding to the light receiving channel 322 of the light receiving element 130 is provided with a second light extinction structure 323. Preferably, the first and second

light attenuating structures

313, 323 may have a serrated surface, which may absorb and eliminate multiple reflections of light rays striking the sides of the light tunnel. Undesired light rays or stray light that strike and are reflected by the channel sidewalls may be absorbed or reduced by the provision of the first and second

light extinction structures

313, 323. Therefore, the structure can further eliminate stray light.

In this embodiment, preferably, the first light guide cover 310 and the second light guide cover 320 may be integrally formed on one surface of the labyrinth 340. Preferably, the first and second light guides are integrally formed with the labyrinth 340. Alternatively, the first light guide 310 and the second light guide 320 may be mounted on the labyrinth 340 by a separate component from the labyrinth 340, or even by a discrete component. In different embodiments, the first light guide cover 310 and the second light guide cover 320 may be configured in various shapes according to actual situations.

Fig. 7 is a schematic view showing an installation position of the shield cover 330 in the more preferred embodiment. As shown in fig. 7, the shielding cover 330 is disposed on the second light guide cover 320 (the second light guide cover 320 accommodates the light receiving element 130 therein). The shielding cover 330 may be a part of the second light guide cover 320, or may be a separate component that can be installed in cooperation with the second light guide cover 320. The shielding cover 330 covers at least the top of the second light guide cover 320, or can further cover the side of the second light guide cover 320, so as to prevent the light that is not scattered by the smoke particles from entering the receiving surface of the light receiving element 130 from the top or even the side of the second light guide cover 320. Of course, in other alternative embodiments, the shield 330 may be absent.

FIG. 8 is a schematic distance diagram of the intersection of two optical components with the optical axis in another preferred embodiment. As shown in fig. 8, in one embodiment, assuming that the optical axis intersection of the light emitting element 120 and the light receiving element 130 is O1, the distance from the light emitting surface of the light emitting element 120 (where the light emitting chip is located) to the optical axis intersection O1 is a, and the distance from the optical axis intersection O1 to the light receiving surface of the light receiving element 130 is b. The inventor of the present invention proposes that the sum of the distance a and the distance b has a great influence on the sensitivity of smoke detection and the light intensity of the detection area. In order to improve the detection sensitivity of the smoke detector and the light intensity of the detection area, the sum of the distance a and the distance b is less than 36mm in the embodiment. For example, the distance a may be set to 10 to 15mm and the distance b may be set to 8 to 12mm, so that the sum of the distance a plus the distance b is preferably 18 to 27 mm. Therefore, the total distance from the emitting light to the back scattering is limited in a better range, so that the detection sensitivity of the smoke detector and the light intensity of the detection area can be improved.

Fig. 9 is a schematic view of a positional relationship between a light-transmissive window and a light assembly according to still another embodiment. As shown in fig. 9, in one embodiment, the distance from the light emitting surface of the first light emitting element 120 in the first light guide cover 310 to the first light transmission window 311 is f, and the area of the first light transmission window 311 is S1. The distance from the light receiving surface of the light receiving element 130 in the second light guide cover 320 to the second light transmission window 321 is e, and the area of the second light transmission window 321 is S2. In order to improve the detection sensitivity of the smoke detector and the light intensity of the detection region, in this embodiment, the ratio of the distance f to the area S1 of the first light-transmitting window 311 is set to about 1 to 1.1. The ratio of the distance e to the area S2 of the second light-transmitting window 321 is set to about 0.4 to 0.5. So set up sensitivity and the regional light intensity value of surveying that can improve the cigarette sense relatively effectively. In the present invention, the light receiving element may have an optical cover with a flush end portion, or may have an optical cover with an arched end portion. With respect to the latter, the light receiving surface thereof is distant from the second light transmitting window, whereby the ratio of the above-mentioned distance e to the area S2 of the second light transmitting window 321 is about 1.

For example, fig. 10 is a schematic size diagram of the first light-transmitting window 311 and the second light-transmitting window 321 in a further embodiment. As shown in fig. 10, if the area At of the first light-transmitting window 311 is set to approximately 8 square millimeters and the area Ar of the second light-transmitting window 321 is set to approximately 8.5 square millimeters, the distance f from the light-emitting surface of the light-emitting element 120 to the first light-transmitting window 311 can be set to 7.0 to 8.5 millimeters, and the distance e from the light-receiving surface of the light-receiving element 130 to the second light-transmitting window 321 can be set to 3.5 to 4.5 millimeters.

In fig. 9, in order to further improve the detection sensitivity of the smoke detector and the light intensity of the detection region, an included angle ω between the optical axis of the light receiving element 130 disposed in the second light guide cover 320 and the plane where the second light transmission window 321 is located may be set to 55 ° to 65 °, and an included angle θ between the optical axis of the light emitting element 120 and the plane where the first light transmission window 311 is located may be set to 180 ° - β - ω, where β represents the included angle between the two optical axes, and ω represents the included angle between the light receiving element 130 disposed in the second light guide cover 320 and the plane where the second light transmission window 321 is located.

Fig. 11 is a schematic view of a detection zone in yet another preferred embodiment. As shown in fig. 11, in one embodiment, in order to further improve the detection sensitivity of the smoke detector and the light intensity of the detection area, a reasonable emission and scattering angle of the light emitting element 120 may be set

And a light receiving angle γ of the light receiving element 130. For example, in one example, the emission scattering angle of the light emitting element 120 may be set

The light receiving angle γ of the light receiving element 130 is approximately equal to 55 ° to 70 °. Thus, a larger detection area as shown in fig. 10 can be obtained.

FIG. 12 is a schematic diagram of the positions of the first light guide cover 310 and the second light guide cover 320 in the labyrinth 340 according to still another preferred embodiment. As shown in FIG. 12, in one embodiment, the intersection of the optical axes of the light emitting element 120 disposed in the first light guide housing 310 and the light receiving element 130 disposed in the second light guide housing 320 is O1. The optical axis intersection point O1 is shifted toward the first light guide cover 310 and the second light guide cover 320 side compared to the geometric center point of the detection chamber 110, and more preferably, the shift distance h may be larger than 4mm, for example, preferably 4.5mm, 5mm, 5.2mm, 6mm, and the like. Therefore, the light background value can be reduced, the directivity of the detector can be improved, and the detection sensitivity of the smoke detector can be further improved. Directionality here refers to the change in detection sensitivity as smoke enters the detection chamber from all directions around the detector. If the sensitivity has obvious correlation with the smoke entering direction, the directivity is poor; if the detection sensitivity is independent of the direction, the surface directivity is good, and the directivity index is closer to 1, the better the directivity is.

Fig. 13A and 13B are partial structural views of a labyrinth 340 in accordance with still another preferred embodiment. As shown in fig. 13A and 13B, in one embodiment, the smoke detector 300 further includes an intra-cavity extinction structure 390 located on the labyrinth 340 and disposed in a circumferential region of the detection cavity 110 facing the first light guide cover 310 and the second light guide cover 320. The intracavity extinction structure 390 can absorb and eliminate the light emitted from the light emitting device onto the wall of the detection chamber 110, so as to prevent the light from directly reflecting into the receiving surface of the light receiving device 130, thereby further eliminating the stray light entering into the receiving surface of the light receiving device 130. The intracavity light extinction structure 390 may be configured to have different structures according to actual situations, or may be configured to have a plurality of bending rib plates 391 extending in the radial direction and arranged in the circumferential direction as shown in fig. 13A and 13B, and the orientation of the bending rib plates 391 varies with position. The structure design can reflect, absorb and eliminate the light irradiated on the wall of the detection cavity by the light-emitting element for multiple times. The intracavity light extinction structure 390 may be integrally formed on the labyrinth 340, i.e., integrally formed with the labyrinth 340; alternatively, it may be a separate element fixed to the labyrinth 340.

As shown in fig. 13B, the radius R of the inner arc formed by the inner end points of the plurality of bending ribs 391, the bending angle μ of each bending rib 391, the angle θ between each bending rib 391 and the radial direction of the probing cavity 110, the angle omicron of the inner end point of each bending rib 391, and the like can be set according to actual conditions. For example, the radius R of the inner arc formed by the inner end points of the plurality of bent rib plates 391 may be set to 15 to 24mm, the bending angle μ of each bent rib plate 391 may be set to 130 to 170 °, each bent rib plate 391 may be set to an angle θ of 4 to 25 ° with respect to the radial direction of the detection cavity 110, and the tip angle of the inner end point of each bent rib plate 361 may be set to 25 to 35 °.

Figure 14 is a schematic view of the position of the smoke detector when mounted on top of a space such as a ceiling. FIG. 15 is a partial cross-sectional view of a smoke detector in accordance with one embodiment. As shown in fig. 14 and 15, in one embodiment, the smoke detector 300 may be a top-entry smoke detector, i.e., the smoke particles 10 enter from the top of the detection chamber 110 through the holes 351 in the labyrinth cover 350. Because smoke particles 10 are easily moved into and out of detector 110 through the top of smoke detector 300 for smoke detector mounted on the top of a space such as a ceiling, and do not accumulate in labyrinth 340. Therefore, the smoke jacking mode is favorable for reducing the accumulation of dust in the detection cavity, the influence of the dust on the detection background is reduced, and the smoke jacking mode has better directivity compared with the side smoke feeding mode.

Fig. 16A and 16B are schematic structural diagrams of the labyrinth cover 350 in one embodiment, and fig. 16C is a schematic relative position relationship between a rib on the labyrinth cover 350 and the first light guide cover 310 and the second light guide cover 320. As shown in fig. 16A to 16C, the labyrinth cover 350 is provided with a rib 352 extending toward the inside of the detection cavity 110 on a surface facing the detection cavity 110, the rib 352 is bent toward one side of the first light guide housing 310 and the second light guide housing 320, and the rib 352 is preferably substantially V-shaped, preferably V-shaped with a flat bottom. The angle of the V-shape may be set according to the actual situation, for example, may be set to 120 °. This structural design can lead to the cigarette/air current that gets into to survey the chamber to make the cigarette flow direction as early as possible survey the region, thereby improve the granule efficiency that gets into to survey the chamber, improve the detectivity of smoke detector.

Fig. 17 is a schematic diagram of light emission of the dual-band light-emitting element 120 according to one embodiment. As shown in fig. 17, in one embodiment, the light emitting element 120 may employ a dual band light emitting element, for example, two bands of red and blue light. When the light emitting element 120 is a dual-band light emitting element, the application can fully utilize the difference in sensitivity of different wavelengths to smoke scattering, thereby improving the smoke detection performance and accuracy of the detector, and further improving the overall performance of the smoke detector. .

Through experiments on the backscatter smoke detector in the first embodiment, it can be found that the detection sensitivity of the backscatter smoke detector can reach more than 0.3dB/m, the directivity is 1.1, and the background value is less than 10 unit counting values.

The second kind of embodiment: forward scatter + backscatter

Fig. 18 to 30 are schematic structural views of another smoke detector in the embodiment of the present invention. Figure 18 is a schematic view of an assembly of a smoke detector according to one embodiment. As shown in fig. 18, the smoke detector 400 has one more light emitting element 410 and one more third light guiding cover 420 than the smoke detector 300 in the first embodiment shown in fig. 3, that is, the embodiment includes two light emitting elements. For convenience of description, in the present embodiment, two light emitting elements are referred to as a first light emitting element 120 and a second light emitting element 410, respectively. Accordingly, the light emitting channel 312 on the first light guide cover 310 may be referred to as a first light emitting channel 312.

In this embodiment, the smoke detector 400 may also adopt a horizontal or horizontal smoke detection mode. Specifically, as shown in the simplified schematic diagram of fig. 19, the plane formed by the optical axis of the first light emitting element 120, the optical axis of the second light emitting element 410, and the optical axis of the light receiving element 130 respectively disposed in the first, third, and second light guiding covers is parallel to the plane of the chassis 341 of the maze element 340.

FIG. 20 is a schematic view of the included angles of the light assemblies mounted in the first, third and second light guides of FIG. 18. As shown in fig. 20, the included angle β between the optical axes of the first light emitting element 120 and the light receiving element 130 is less than 90 °, i.e., a backscattering type structure, which is consistent with fig. 6. The second light emitting element 410 is adapted to be accommodated in the third light guiding cover 420, and forms an angle α with the optical axis of the light receiving element 130 larger than 90 °, that is, forms a forward scattering structure as shown in fig. 1, and forms a forward scattering + backward scattering structure. Specifically, in order to increase the intensity of the scattered light finally incident to the light receiving element 130, the position of the third light guide 420 may be preferentially set in addition to the positions where the first and second light guides are preferably set as described in the first kind of embodiments. In addition to the optical axis included angle β of the first light emitting element 120 and the light receiving element 130 placed therein being 50 ° to 70 °, the optical axis included angle α of the second light emitting element 410 and the light receiving element 130 may be 110 ° to 140 °, and α is 120 ° more preferably.

Fig. 21A and 21B are schematic structural views of first, second, and third light guide covers according to an embodiment. As shown in fig. 21A and 21B, the structures of the first and second light guide covers are the same as those in fig. 6A and 6B, and are not described again here. The third light guide cover 420 has a third light transmission window 421 and a second light transmission channel 422, and the third light guide cover 420 is disposed in the detection cavity 110 and is adapted to accommodate or mount the second light emitting element 410, so that the emergent light of the second light emitting element 410 can pass through the light transmission channel 422 and the third light transmission window 421 and be projected into the detection cavity 110.

In this embodiment, the third light guide cover 320 may also be integrally formed on the labyrinth 340. Preferably, the first, second and third light guides are integrally formed with the labyrinth 340. Alternatively, the first, second and third light guides may be mounted on the labyrinth 340 by a separate component from the labyrinth 340, or even a discrete component. In different embodiments, the first, second and third light guides can be arranged in various shapes according to actual conditions.

In this embodiment, besides the first light-transmitting window 311 and the second light-transmitting window 321 can be located in the same plane as described in the first embodiment, the third light guide cover 420 can further have a first light-shielding extension 423 disposed on a side of the third light-transmitting window 421 close to the second light-transmitting window 321, and the first light-shielding extension is configured to prevent light projected from the third light-transmitting window 421 from directly entering the second light-transmitting window 321. Preferably, an edge point of the third light-transmitting window 421, which is away from the light-receiving element 130, a top end of the first light-shielding extension 423, and an edge point of the second light-transmitting window 321, which is away from the second light-emitting element 410, may be located on the same straight line. In this embodiment, it is further preferable that a light shielding protrusion 314 is further disposed on the first light guide cover 310 and disposed between the first light transmission window 311 and the second light transmission window 321 to further prevent the light emitted from the first light transmission window 311 from directly entering the second light transmission window 321. With the above structure, the light that is not scattered by the smoke particles can be prevented from entering the receiving surface of the light receiving element 130, and the detection result can be prevented from being disturbed, that is, the shielding of the unwanted stray light can be realized.

As shown in fig. 21B, in addition to the first light extinction structure 313 preferably disposed in the first light guide cover 310 and the second light extinction structure 323 disposed in the second light guide cover 320 as described in the first embodiment, a third light extinction structure 424 may also be preferably disposed in the third light guide cover 420 corresponding to at least one side of the light emitting channel 422 of the second light emitting element 410. Preferably, the first, second and third

light attenuating structures

313, 323, 424 may have a serrated surface, which absorbs and eliminates multiple reflections of light impinging on the sides of the light tunnel. The provision of a light-attenuating structure within the light channels may absorb or reduce unwanted or stray light impinging on the side walls of the light channels.

In addition, the second light extinction structure 323 in the second light guide cover 320 may further have a light trap portion 3231 located in a region close to the second light transmission window 321 and close to the second light emitting element 410, and the light trap portion 3231 has at least one recess, and the depth of the recess is greater than other portions of the second light extinction structure 323. The design of the light trap portion can further absorb or reduce the undesired stray light emitted by the second light emitting element 410, reflected by the inner sidewall of the detection cavity, and then irradiated to the channel sidewall region through the second light-transmitting window, thereby preventing the stray light from entering the light receiving element.

In this embodiment, the installation manner of the shielding cover 330 may be the same as that in fig. 7, and is not described herein again.

FIG. 22 is a schematic distance diagram of the intersection of three optical components with the optical axis in yet another preferred embodiment. As shown in fig. 22, it is assumed that the optical axis intersection of the first light emitting element 120 and the light receiving element 130 is O1 (see fig. 8), and the optical axis intersection of the second light emitting element 410 and the light receiving element 130 is O2. Further, it is assumed that the distance from the light emitting surface of the first light emitting element 120 (where the light emitting chip is located) to the optical axis intersection O1 is a (see fig. 8), and the distance from the optical axis intersection O1 to the light receiving surface of the light receiving element 130 is b (see fig. 8). Meanwhile, assume that the distance from the light emitting surface of the second light emitting element 410 (where the light emitting chip is located) to the optical axis intersection O2 is c, and the distance from the optical axis intersection O2 to the light receiving surface of the light receiving element 130 is d. Thus, in addition to the sum of the distance a and the distance b being smaller than 36mm as described in the first embodiment, the sum of the distance c and the distance d may be set smaller than 49 mm. For example, in addition to the distance a being 10 to 15mm and the distance b being 8 to 12mm, the distance c being 15 to 20mm and the distance d being 7 to 12mm, the sum of the distance a plus the distance b is preferably 18 to 27mm, and the sum of the distance c plus the distance d is preferably 22 to 32 mm.

Fig. 23 is a schematic view showing a positional relationship between the light-transmissive window and each of the optical members according to still another embodiment. As shown in fig. 23, the distance from the light emitting surface (i.e., the position of the light emitting chip) of the first light emitting element 120 in the first light guide cover 310 to the first light transmission window 311 is f (see fig. 9), and the area of the first light transmission window 311 is S1. The distance from the light receiving surface of the light receiving element 130 in the second light guide cover 320 to the second light transmission window 321 is e, and the area of the second light transmission window 321 is S2. The distance from the light emitting surface (i.e., the position of the light emitting chip) of the second light emitting element 410 in the third light guide cover 420 to the third light transmission window 421 is g, and the area of the third light transmission window 421 is S3. In this embodiment, the ratio of the distance f to the area S1 of the first light-transmitting window 311 is set to 1 to 1.1, and the ratio of the distance e to the area S2 of the second light-transmitting window 321 is set to 0.4 to 0.5 or about 1, as described in the first embodiment, and the ratio of the distance g to the area S3 of the third light-transmitting window is set to 1 to 1.1.

For example, fig. 24 is a schematic size diagram of the first light-transmitting window 311, the third light-transmitting window 421 and the second light-transmitting window 321 in another embodiment. As shown in fig. 24, in the present embodiment, if the area At of the first light-transmitting window 311 is set to be approximately equal to 8 square millimeters and the area Ar of the second light-transmitting window 321 is set to be approximately equal to 8.5 square millimeters as described in the first embodiment, the area At of the third light-transmitting window 421 may be set to be approximately equal to 8 square millimeters. Accordingly, the distance g from the light emitting surface of the second light emitting element 410 to the third light transmitting window 421 may be set to be 7.0 to 8.5 mm, in addition to the distance f from the light emitting surface of the first light emitting element 120 to the first light transmitting window 311 being set to be 7.0 to 8.5 mm and the distance e from the light receiving surface of the light receiving element 130 to the second light transmitting window 321 being set to be 3.5 to 4.5mm as described in the first embodiment.

In fig. 23, in addition to the angle ω between the optical axis of the light receiving element 130 disposed in the second light guide cover 320 and the plane where the second light transmission window 321 is located being 55 ° to 65 °, and the angle θ between the optical axis of the first light emitting element 120 and the plane where the first light transmission window 311 is located being 180 ° - β - ω, as described in the first embodiment, the angle η between the optical axis of the second light emitting element 410 and the plane where the third light transmission window 421 is located being 50 ° to 90 °. For example, η may be set to 50 ° to 70 ° more preferably. Where β represents an angle between two optical axes of the first light emitting element 120 and the light receiving element 130.

FIG. 25 is a schematic view of a detection zone in one embodiment. As shown in FIG. 25, in addition to further improving the detection sensitivity of the smoke detector and the light intensity in the detection area as described in the first embodiment, a reasonable scattering angle of the first light-emitting element 120 can be set

And the light receiving angle y of the light receiving element 130, a reasonable emission scattering angle epsilon of the second light emitting element 410 can be set. For example, in one example, the emission divergence angle of the first light emitting element 120 can be set

The light receiving angle γ of the receiving element 130 is approximately equal to 55 ° to 70 °, and the second light emission is performedThe emission scattering angle epsilon of the element 410 is approximately 10 deg. -15 deg.. A larger detection area can thus be obtained as shown in fig. 24.

FIG. 26 is a schematic diagram of the positions of the first light guide cover 310, the third light guide cover 420 and the second light guide cover 320 in the labyrinth 340 according to still another preferred embodiment. As shown in fig. 26, the intersection point O1 of the optical axes of the first light emitting element 120 disposed in the first light guide cover 310 and the light receiving element 130 disposed in the second light guide cover 320 is shifted toward the first light guide cover 310 and the second light guide cover 320 side compared with the geometric center point of the detection cavity 110, and more preferably, the shift distance h may be more than 4mm, such as 4.5mm, 5mm, 5.2mm, 6mm, and so on. This reduces stray light that impinges into the detection chamber 110.

Fig. 27 and 28 are partial structural views of a labyrinth 340 in one embodiment. As shown in fig. 27 and 28, in one embodiment, the smoke detector 300 further includes an intra-cavity extinction structure 390 located on the labyrinth 340 and disposed in a circumferential region of the detection cavity 110 facing the first light guide cover 310, the second light guide cover 320 and the third light guide cover 420. The intracavity light extinction structure 390 may be configured into different structures according to actual conditions, or may be configured into a plurality of bending rib plates 391 extending along the radial direction and arranged along the circumferential direction as shown in fig. 27 and fig. 28, and the orientation of the bending rib plates 391 changes with position. The intracavity light extinction structure 390 may be integrally formed on the labyrinth 340, i.e., integrally formed with the labyrinth 340; alternatively, it may be a separate element fixed to the labyrinth 340.

As shown in fig. 28, the radius R of the inner arc formed by the inner end points of the plurality of bending ribs 391, the bending angle μ of each bending rib 391, the angle θ between each bending rib 391 and the radial direction of the probe cavity 110, the angle omicron of the inner end point of each bending rib 391, and the like can be set according to actual conditions. For example, the radius R of the inner arc formed by the inner end points of the plurality of bent rib plates 391 may be set to 15.0 to 24mm, the bending angle μ of each bent rib plate 391 may be set to 130 to 170 °, each bent rib plate 391 may be set to 4 to 25 ° with respect to the radial direction of the detection cavity 110, and the tip angle of the inner end point of each bent rib plate 391 may be set to 25 to 35 °.

FIG. 29 is a schematic view of the installation position of the light guide 360 according to one embodiment. As shown in fig. 29, the light guide 360 may be installed in any one of the A, B, C, D four regions, because the four regions do not belong to the detection regions of the first light emitting element 120, the second light emitting element 410 and the light receiving element 130, so that the influence of stray light caused by the light guide 360 on the smoke detector can be avoided. The light guide 360 is arranged in the region a in the example shown in fig. 29.

FIG. 30 is a diagram illustrating a second light emitting element 410 that is a dual band light emitting element according to one embodiment. As shown in fig. 30, in addition to the first light emitting element 120 which can employ a dual band light emitting element as described in the first embodiment, the second light emitting element 410 can also employ a dual band light emitting element, for example, two bands of red and blue light. By adopting the dual-band light-emitting element, the sensitivity of different wavelengths to smoke scattering can be fully utilized, and the smoke detection performance and accuracy of the detector are improved, so that the overall performance of the smoke detector is further improved.

In addition, the smoke detector 400 in this embodiment may also be a top-in smoke detector, which is not described herein again.

The third kind of embodiment: forward scattering

The structure of the smoke detector in this type of embodiment may be identical to the structure of the smoke detector in the second type of embodiment, except that the first light emitting element 120 is not installed therein.

Alternatively, if only a forward scattering structure is required, the structure of the first light guide cover 310 in FIGS. 18 to 30 may also be removed, and only the structure of the second light guide cover 320 for accommodating the light receiving element and the third light guide cover 420 for accommodating the second light emitting element 410 may be left.

In addition, the present invention is described in the above embodiments only by taking the horizontal smoke detection as an example, and the structure proposed by the present invention may also be applied to all or part of the vertical smoke detection structure.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A smoke detector comprising a detection chamber (110) into which particles floating near said smoke detector can enter, at least one light emitting element and a light receiving element (130) disposed within the detection chamber, characterized in that said smoke detector further comprises:

a first light guide cover (310) located in the detection chamber (110) and having a first light-transmitting window (311), the first light guide cover (310) being adapted to accommodate a first light-emitting element (120) so that the emergent light of the first light-emitting element (120) can pass through the first light-transmitting window (311) and be projected to the particles in the detection chamber (110);

a second light guide (320) located in the detection chamber (110) and having a second light-transmissive window (321), the second light guide (320) being adapted to receive the light-receiving element (130) such that the light-receiving element (130) can receive light incident through the second light-transmissive window (321);

wherein the first light-transmitting window (311) and the second light-transmitting window (321) are located in the same plane, and

an included angle beta between two optical axes of the light emitting element (120) arranged in the first light guide cover (310) and the light receiving element (130) arranged in the second light guide cover (320) is smaller than 90 degrees, and a plane where the two optical axes are located is perpendicular to a plane where the first light transmission window (311) and the second light transmission window (321) are located together.

2. The smoke detector according to claim 1, wherein a sum of a distance a from a point of intersection (O1) of two optical axes of said first light emitting element (120) disposed in said first light guide housing (310) and said light receiving element (130) disposed in said second light guide housing (320) to a light emitting surface of said light emitting element (120) in said first light guide housing (310), and a distance b from said point of intersection (O1) of said optical axes to a light receiving surface of said light receiving element (130) disposed in said second light guide housing (320) is less than 36 mm.

3. The smoke detector of claim 1, wherein an optical axis intersection (O1) of said first light emitting element (120) disposed within said first light guide housing (310) and said light receiving element (130) disposed within said second light guide housing (320) is offset towards said first light guide housing (310) and second light guide housing (320) sides compared to a geometric center point of said detection cavity (110).

4. The smoke detector according to claim 1, wherein said first light emitting element (120) disposed in said first light guide housing (310) and said light receiving element (130) disposed in said second light guide housing (320) have an included angle β of 50 ° to 70 °.

5. The smoke detector of claim 1, further comprising a shielding cover (330) covering at least a top portion of said second light guide (320) to prevent light from entering said light receiving element (130) from the top portion of said second light guide (320).

6. The smoke detector of claim 1,

a first light extinction structure (313) is arranged on the side surface of the first light guide cover (310) corresponding to the light emitting channel (312) of the first light emitting element (120), and/or,

and a second extinction structure (323) is arranged on the side surface, corresponding to the light receiving channel (322) of the light receiving element (130), in the second light guide cover (320).

7. The smoke detector of claim 1, further comprising an intra-cavity extinction structure (390) disposed within a circumferential region of the detection cavity (110) facing the first light guide (310) and the second light guide (320);

the intracavity light extinction structure (390) comprises a plurality of bending rib plates (391) which extend along the radial direction and are arranged along the circumferential direction, and the orientation of the bending rib plates changes along with the position.

8. The smoke detector according to claim 1, further comprising a labyrinth cover (350), wherein a rib (351) extending towards the inside of the detection cavity (110) is disposed on a surface of the labyrinth cover (350) facing the detection cavity (110), and the rib (351) is bent towards one side of the first light guide cover (310) and the second light guide cover (320).

9. The smoke detector of claim 1,

the ratio of the distance f from the light emitting surface of the first light emitting element (120) placed in the first light guide cover (310) to the first light transmission window (311) to the area of the first light transmission window (311) is 1-1.1; and/or

The ratio of the distance e from the light receiving surface of the light receiving element (130) disposed in the second light guide cover (320) to the second light transmission window (321) to the area of the second light transmission window (321) is 0.4 to 0.5 or 1.

10. The smoke detector of claim 1, further comprising:

a third light guide cover (420) located in the detection chamber (110) and having a third light-transmitting window (421), the third light guide cover (420) being adapted to receive or mount a second light-emitting element (410) such that an included angle α between optical axes of the second light-emitting element (410) and the light-receiving element (130) disposed in the second light guide cover (320) is greater than 90 °; and the second light emitting element (130) is capable of projecting light through the third light transmissive window (421) towards the particles in the detection chamber (110).

11. The smoke detector according to claim 10, wherein a sum of a distance c from an optical axis intersection point (O2) of said second light emitting element (410) disposed in a third light guide housing (420) and said light receiving element (130) disposed in a second light guide housing (320) to a light emitting surface of said second light emitting element (410), plus a distance d from said optical axis intersection point (O2) to a light receiving surface of said light receiving element (130) disposed in a second light guide housing (320), is less than 49 mm.

12. The smoke detector according to claim 10, wherein an angle η between an optical axis of said second light emitting element (410) disposed in said third light guide cover (420) and a plane of said third light transmission window (421) is 50 ° to 90 °; and/or

The ratio of the distance g from the light emitting surface of the second light emitting element (410) placed in the third light guide cover (420) to the third light transmission window (421) to the area of the third light transmission window (421) is 1-1.1.

13. Smoke detection probe according to claim 10,

the first light guide cover (310) further has a light shielding protrusion (314) disposed between the first light transmission window (311) and the second light transmission window (321) to prevent light emitted from the first light transmission window (311) from directly entering the second light transmission window (321).

14. The smoke detector of claim 10,

the third light guide cover (420) is provided with a first shading extension part (423) on one side of the third light transmission window (421) close to the second light transmission window (321), and the first shading extension part is set to prevent light projected from the third light transmission window (421) from directly entering the second light transmission window (321).

15. The smoke detector according to claim 14, wherein an edge point of said third light transmissive window (421) far from said light receiving element (130), a top end of said first light blocking extension (423), and an edge point of said second light transmissive window (321) far from said second light emitting element (410) are located on a same straight line.

16. The smoke detector according to claim 10, wherein a second light extinction structure (323) is disposed in the second light guide cover (320) corresponding to a side of the light receiving channel (322) of the light receiving element (130), the second light extinction structure (323) has a light trap portion (3231) located in a region close to the second light transmissive window (321) and close to the second light emitting element (410), and the light trap portion (3231) has at least one recess having a depth greater than other portions of the second light extinction structure (323).

17. The smoke detector of claim 1, wherein said smoke detector is a jack-in smoke detector.

18. The smoke detector of claim 1, wherein said first light emitting element (120) is a dual band light emitting element.

19. The smoke detector of claim 1, wherein said first light guide shroud (310) and said second light guide shroud (320) are an integral piece.

20. The smoke detector according to claim 1, wherein a distance a from a point of intersection (O1) of two optical axes of said first light emitting element (120) disposed in said first light guide housing (310) and said light receiving element (130) disposed in said second light guide housing (320) to a light emitting surface of said light emitting element (120) in said first light guide housing (310), plus a distance b from said point of intersection (O1) of said optical axes to a light receiving surface of said light receiving element (130) disposed in said second light guide housing (320) is less than 32 mm.

21. A smoke detector according to claim 3, wherein an optical axis crossing (O1) of said first light emitting element (120) placed in said first light guide housing (310) and said light receiving element (130) placed in said second light guide housing (320) is shifted towards said first light guide housing (310) and second light guide housing (320) side compared to a geometrical centre point of said detection cavity (110) by a distance h larger than 4 mm.

22. The smoke detector according to claim 4, wherein an angle ω between an optical axis of the light receiving element (130) disposed in the second light guide cover (320) and a plane in which the second light transmission window (321) is located is 55 ° to 65 °; an included angle θ between an optical axis of the first light emitting element (120) and a plane where the first light transmission window (311) is located is 180 ° - β - ω, where β represents the included angle between the two optical axes, and ω represents an included angle between the light receiving element (130) disposed in the second light guide cover (320) and the plane where the second light transmission window (321) is located.

23. A smoke detector according to claim 6, wherein said light extinction structure (313, 323) has a serrated surface.

24. The smoke detector according to claim 10, wherein an angle η between an optical axis of said second light emitting element (410) disposed in said third light guide cover (420) and a plane of said third light transmitting window (421) is 50 ° -70 °.

25. The smoke detector according to claim 8, wherein said rib (351) is V-shaped.

26. The smoke detector of claim 10, wherein said second light emitting element (410) is a dual band light emitting element.