Modular photoelectric smoke sensor tube

Abstract

A smoke detector for an air duct includes a photoelectric detection system and a sampling space in fluid communication with the air duct, wherein the sampling space is enclosed by a removable sampling space enclosure having an optical window, and the photoelectric detection system is located adjacent to the optical window. The sampling space enclosure can be removed or replaced without removing or replacing the entire smoke detector.

Description

Technical Field

[0001] Embodiments disclosed herein relate to smoke detectors, and more particularly to photoelectric smoke detectors for air ducts. Background Art

[0002] A smoke detector is a device that detects smoke and sounds an alarm. A photoelectric smoke detector operates based on the principle of light reflection and generally consists of a light emitter, a light receiver, and an optical chamber. When smoke is absent from the optical chamber and the chamber is empty or nearly empty, the light receiver typically receives a small amount of light reflected from the chamber surfaces. On the other hand, when smoke is present in the optical chamber, the light receiver receives more light due to light reflected from smoke particles. When the amount of received light exceeds a threshold level, an alarm is triggered.

[0003] Detectors for sensing one or more conditions within the ductwork of a heating, ventilation, and air conditioning system are typically mounted to a flange or other member and / or the outside of the air duct and include a sampling tube extending laterally from the outside into the ductwork. Air within the ductwork flows into an inlet formed in the sampling tube and into a smoke sensor located in a housing outside the ductwork. The air then returns to the interior of the ductwork via an outlet flow tube.

[0004] Dust and debris can accumulate inside smoke detectors, leading to false alarms and frequent maintenance. Maintenance of duct detectors is typically a time-consuming process with limited efficiency. Therefore, maintenance of duct detectors is often accompanied by replacement of the detector. Summary of the Invention

[0005] According to an embodiment, a smoke detector for an air duct includes a sampling space in fluid communication with the air duct and a photoelectric detection system, wherein the sampling space is enclosed by a removable sampling space enclosure having an optical window, and the photoelectric detection system is located near the optical window.

[0006] In addition to or alternatively to one or more of the features described above, in a further embodiment the removable sampling space enclosure comprises an electrically conductive material.

[0007] In addition to or alternatively to one or more of the features described above, in a further embodiment, the removable sampling space enclosure absorbs infrared light.

[0008] In addition to or as an alternative to one or more of the features described above, in a further embodiment, the photodetection system includes at least one light emitter and at least one light receiver. The at least one light receiver can receive light at different angles.

[0009] In addition to or alternatively to one or more of the features described above, in a further embodiment, at least one light emitter emits multiple wavelengths.

[0010] In addition to or as an alternative to one or more of the features described above, in a further embodiment the smoke detector comprises an optical module.The optical module may form part of the sampling space envelope.

[0011] In addition to or alternatively to one or more of the features described above, in a further embodiment the removable sampling space enclosure includes a cleaning port.

[0012] In addition to or as an alternative to one or more of the features described above, in further embodiments the optical window has antistatic or hydrophobic properties.

[0013] According to another embodiment, a method for detecting smoke in an air duct includes emitting light into a removable sampling space enclosure, receiving the light from the sampling space enclosure at multiple angles using a photodetection system, and comparing the emitted light to the received light. The sampling space enclosure includes an optical window and encloses a sampling space in fluid communication with the air duct. The photodetection system includes at least one light emitter and at least one light receiver and is located near the optical window. The photodetection system is positioned to emit light into the sampling space and receive light from the sampling space.

[0014] In addition to or alternatively to one or more of the features described above, in a further embodiment, the photodetection system includes a plurality of light receivers configured to receive light at different angles.

[0015] According to another embodiment, a method of maintaining a smoke detector for an air duct includes cleaning or replacing at least a portion of a sampling space enclosure, wherein the sampling space enclosure encloses a sampling space in fluid communication with the air duct, and the smoke detector includes a photoelectric detection system located proximate an optical window of the sampling space enclosure.

[0016] In addition to or alternatively to one or more of the features described above, in a further embodiment, the sampling space enclosure includes a cleaning port, and the cleaning includes drawing or applying compressed air through the cleaning port.

[0017] In addition to or alternatively to one or more of the features described above, in a further embodiment, cleaning includes removing at least a portion of the sampling space enclosure from the smoke detector, and removing contaminants from the sampling space enclosure and the optical window.

[0018] Additionally or alternatively to one or more of the features described above, in a further embodiment the sampling space enclosure has at least two parts, and cleaning includes removing one part to provide access to the interior of the sampling space enclosure.

[0019] Additionally or alternatively to one or more of the features described above, in a further embodiment, the sampling space envelope has at least two parts, and replacing the sampling space envelope includes replacing one or more parts of the sampling space envelope.

[0020] In addition to or alternatively to one or more of the features described above, in a further embodiment, the sampling space enclosure includes a first portion, a second portion, an optical mode, and an optical window, and replacing the sampling space enclosure includes replacing the first portion, the second portion, or both.

[0021] In addition to or as an alternative to one or more of the features described above, further embodiments further include cleaning the optical module, the optical window, or both. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The following description should not be considered limiting in any way. Referring to the accompanying drawings, like elements are numbered alike:

[0023] Figure 1 is a cross section of an exemplary smoke detector;

[0024] Figure 2 is an exploded view of an exemplary smoke detector; and

[0025] Figure 3 is a top view of an exemplary smoke detector. DETAILED DESCRIPTION

[0026] A smoke detector for an air duct includes a sampling space in fluid communication with the air duct and a photoelectric detection system. The sampling space is enclosed by a sampling space enclosure having an optical window. The photoelectric detection system includes at least one light emitter and at least one light receiver. The at least one light emitter and at least one light receiver are positioned adjacent to the optical window. The sampling space enclosure is removable and can be cleaned or replaced as needed without having to replace the entire smoke detector. The ability to clean and / or replace the sampling space enclosure helps reduce the number of false positives due to dust and other accumulated material, and maintains the sensitivity of the smoke detector.

[0027] A detailed description of one or more embodiments of the disclosed apparatus and method is given herein by way of example and not limitation with reference to the accompanying figures.

[0028] Figure 1A smoke detector 10 is shown. The smoke detector includes an inlet 30, an outlet 40, and a sampling space 50. The sampling space 50 is enclosed by a removable sampling space enclosure 55. The removable sampling space enclosure 55 has one or more optical windows 60 and may include an optical module 150. The removable sampling space enclosure 55 may include an optional cleaning port 110. The cleaning port allows the use of suction, compressed air, or a combination thereof for cleaning the removable sampling space enclosure 55, for example by using air to force dust or other accumulated materials that may cause obstruction of light in the sampling space enclosure 55 through the sampling space enclosure 55. A photoelectric detection system 70 is located near the optical window 60. The sampling space 50 is in fluid communication with an air duct (not shown). As air moves through the air duct, a portion of the air enters the inlet 30 and moves through the sampling space 50 and exits through the outlet 40 to rejoin the air passing through the duct.

[0029] The removable sampling space enclosure may be unitary or may have more than one part. At least a portion of the removable sampling space enclosure 55 may be removed for cleaning or replacement without having to replace the entire smoke detector 10 or any of the other components of the detector 10. The ability to remove at least a portion of the removable sampling space enclosure 55 and leave the remainder of the system in place facilitates maintenance, reduces false positives due to dust or other accumulated materials, and is cost-effective. In some embodiments, one or more of the optical module 150 and the optical window 60 may be detachable from the removable sampling space enclosure 55. This modularity allows for inspection, evaluation, and maintenance / replacement of each component as required.

[0030] The sample space enclosure 55 has receiving ends 80 and 90 that facilitate removal and replacement of the sample space enclosure 55. The receiving ends 80, 90 may include gaskets or other types of seals. Alternatively, a gasket or seal may be positioned on each end of the device mount 200 or on the inlet 30 and outlet 40.

[0031] The removable sampling space enclosure 55 absorbs infrared light and may be made of an infrared absorbing material or may be coated with an infrared absorbing coating. In some embodiments, the sampling space enclosure 55 comprises a conductive material comprising an IR absorbing material. The sampling space enclosure 55 comprises one or more optical windows 60 to enable detection and optionally measurement of smoke and other materials. The optical window 60 transmits greater than or equal to 90% of the light transmitted by the detection system for effective detection and / or measurement, and the optical window may be made of a polymer, glass or other suitable material. The optical window 60 may exhibit antistatic and / or superhydrophobic properties in the form of a coating, which may facilitate cleaning of the optical window, the sampling space enclosure, or both. The antistatic and / or superhydrophobic properties may also reduce the likelihood of particles remaining on the optical window and interfering with detection, measurement, or both. The sampling space 50 may have any shape that does not interfere with the detection system 10. Exemplary cross-sectional shapes include circular, square, and rectangular.

[0032] Figure 2 is an exploded view of an embodiment of a smoke detector 10 showing the inlet 30 and outlet 40, as well as the mounting element 200. In this exemplary embodiment, the removable sampling space enclosure comprises at least two parts, shown here as a first removable sampling space enclosure part 55a and a second removable sampling space enclosure part 55b. Also shown are an optical window 60, a photoelectric detection system 70, and an optical module 150.

[0033] A photodetection system 70 is located near the optical window 60. The photodetection system 70 uses light to assess the amount of air (in this example, the amount of air within the sampling space 50) present regarding a condition, such as a fire or other hazard. In this specification, the term "light" refers to coherent or incoherent radiation at any frequency or combination of frequencies in the electromagnetic spectrum. In this example, the photodetection system 70 uses light scattering to determine the presence of particles in the sampling space, indicating the presence of a threshold condition or event. In this specification, the term "scattered light" can include any change in the amplitude / intensity or direction of the incident light, including reflection, refraction, diffraction, absorption, and scattering in any / all directions. In this example, light is emitted through the optical window 60 into the sampling space 50. When the light encounters an object (e.g., a smoke particle or gas molecule) suspended (i.e., floating) in the surrounding medium (air), the light is scattered and / or absorbed due to the difference in the object's refractive index compared to the surrounding medium (air). Depending on the object, the light can be scattered in all different directions. Detecting the light scattered by the object can provide information about the sampling space, including determining the presence of a threshold condition or event.

[0034] Light scattering is a physical property attributed to the interaction of light with the atoms or surfaces of a material. For light emitted from a source, the angle of redirection depends on the material composition and geometry. The redirection of light can be isotropic, where each angle receives the same amount of radiation. Alternatively, the redirection of light can be anisotropic, where a certain amount of light is redirected inconsistently with respect to angle. The amount of anisotropy depends on the optical and electronic properties combined with the geometric properties of the material. Anisotropy is also frequency-dependent. In practice, this principle can be used to distinguish one material from another; one group of materials from another; or combinations of materials and groups of materials.

[0035] The photodetection system 70 includes at least one light emitter and at least one light receiver. The at least one emitter is capable of emitting multiple wavelengths. The at least one receiver is capable of detecting (receiving) multiple wavelengths. The ability to emit and detect multiple wavelengths facilitates distinguishing between different types of materials in the sampling space. The emitter and receiver may include optical fiber cables, laser diodes, photodiodes, or other types of light generation and reception.

[0036] Light from the emitter passes through optical window 60 into sampling space 50 . Figure 3 An exemplary arrangement of emitters and receivers is shown in FIG. A first infrared emitter 300 , a blue light emitter 310 , a second infrared emitter 320 , and a receiver 330 are located near the optical window 60 and the optical module 150 .

[0037] The light interacts with any particles present in the sampling space enclosure 50 and is reflected or transmitted back to the receiver. A comparison of the light provided by the transmitter and / or a change in the light reflected back to the receiver will indicate whether there is an atmospheric change in the sampling space 50 that causes scattering of light. Scattered light, as described herein, is intended to additionally include reflected light, transmitted light, and absorbed light. Although the detection system is described as using light scattering to determine a condition or event, embodiments that use light obscuration, absorption, and fluorescence in addition to or in lieu of light scattering are also within the scope of the present disclosure.

[0038] In some embodiments, light from the photodetection system 70 passes through an optical module, guide, lens, or other distribution device, which for convenience is described herein as an "optical module" 150. The optical module enables focusing light from multiple angles. The optical module can be constructed from any suitable material, including but not limited to, for example, fiber optics, free-space optics, molded plastic optics, or photonic integrated circuits. In addition, the optical module can be integrated with the transmitter, receiver, or both.

[0039] The photoelectric detection system 70 can be used to distinguish smoke from other types of hazardous conditions or nuisances. Each emitter is associated with one or more receivers for collecting / receiving scattered light from the sampling space 50. Each of the one or more receivers is oriented at a different angle relative to the emitter. For example, a first angle is formed between the emitter and the first receiver, and a second angle is formed between the emitter and the second receiver. The first angle and the second angle are known and different. In some embodiments, the different angles can be achieved by physically orienting / positioning the receivers differently. In other embodiments, the different angles can be achieved by using multiple emitters. In other embodiments, an optical module can be used to receive scattered light at one or more receivers from different scattering angles. The optical module can be operably connected and constructed to support the emitter and the multiple receivers so that the multiple receivers each receive scattered light from a desired angle.

[0040] The photoelectric detection system may include a control system (not shown). The control system may be used to manage the operation of the detection system, and the control system may include control of components, data acquisition, data processing, and data analysis. In some embodiments, the detection system may include other components to detect other conditions (such as air quality). The control system includes a processor and a memory. Exemplary processors include microprocessors, system on chip (SOC), field programmable gate array (FGPA), etc. The processor may be coupled to at least one light emitter and at least one light receiver. The at least one light receiver is configured to convert the received scattered light into a corresponding signal that can be received by the processor. The signal output and the signal from the emitted light may be compared by the processor to determine whether a threshold condition exists.

[0041] In addition to being operably coupled to at least one transmitter and at least one receiver, the control system may be associated with one or more input / output devices. In embodiments, the input / output devices may include alarms or other signals, or fire suppression systems that are triggered upon detection of a predefined event or condition. It should be understood that the term "alarm," as used herein, may refer to any of the possible outcomes of a detection.

[0042] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, indicate the presence of the specified features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0043] Although the present disclosure has been described with reference to one or more exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the basic scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiments disclosed as the best mode for carrying out the concepts of the present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.

Claims

1. A smoke detector for an air duct, comprising a photoelectric detection system and a sampling space in fluid communication with the air duct, wherein the sampling space is enclosed by a removable sampling space enclosure having an optical window, and the photoelectric detection system is located adjacent to the optical window; in, At least a portion of the removable sampling space enclosure can be removed without removing the photodetection system; Wherein, the removable sampling space enclosure is located outside the air duct.

2. The smoke detector according to claim 1, wherein: The removable sampling space enclosure comprises an electrically conductive material.

3. The smoke detector according to claim 1 or 2, characterized in that: The removable sampling space enclosure absorbs infrared light.

4. The smoke detector according to claim 1 or 2, characterized in that: The photodetection system includes at least one light emitter and at least one light receiver.

5. The smoke detector according to claim 4, wherein: The at least one light receiver receives light from the at least one light emitter at different angles.

6. The smoke detector according to claim 4, wherein: The at least one light emitter emits a plurality of wavelengths.

7. The smoke detector according to claim 1 or 2, characterized in that: The smoke detector further includes an optical module.

8. The smoke detector according to claim 7, wherein: The optical module forms part of the removable sampling space enclosure.

9. The smoke detector according to claim 1 or 2, characterized in that: The removable sampling volume enclosure further includes a cleaning port.

10. The smoke detector according to claim 1 or 2, characterized in that: The optical window has antistatic or hydrophobic properties.

11. The smoke detector according to claim 1 or 2, characterized in that: The removable sampling space enclosure comprises two parts.

12. A method for detecting smoke in an air duct using the smoke detector according to any one of claims 1 to 11, the method comprising: Launching light into a removable sampling space envelope, receiving light from the removable sampling space enclosure at multiple angles using a photodetection system, and The emitted light is compared to the received light.

13. A method of maintaining a smoke detector for an air duct, comprising cleaning or replacing at least a portion of a removable sampling space enclosure without removing a photoelectric detection system, wherein the removable sampling space enclosure encloses a sampling space in fluid communication with the air duct, and the smoke detector includes the photoelectric detection system located adjacent an optical window of the removable sampling space enclosure; in, The removable sampling space enclosure is located outside the air duct.

14. The method according to claim 13, characterized in that The removable sampling volume enclosure includes a cleaning port, and cleaning includes drawing or applying compressed air through the cleaning port.

15. The method according to claim 13, characterized in that Cleaning includes removing at least a portion of the removable sampling space enclosure from the smoke detector and removing contaminants from the removable sampling space enclosure and the optical window.

16. The method according to claim 13, characterized in that The removable sampling space enclosure has at least two parts, and cleaning includes removing one part to provide access to an interior of the removable sampling space enclosure.

17. The method according to claim 13, wherein The removable sampling space enclosure has at least two parts, and replacing the removable sampling space enclosure includes replacing one or more parts of the removable sampling space enclosure.

18. The method according to claim 17, characterized in that The removable sampling space enclosure includes a first portion, a second portion, an optical module, and an optical window, and replacing the removable sampling space enclosure includes replacing the first portion, the second portion, or both.

19. The method according to claim 18, characterized in that The method further includes cleaning the optical module, the optical window, or both.

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