Device and method for operating a smoke detector

Abstract

A method (200) for operating a smoke detector (190; 300) comprises detecting (210), by means of at least one sensor device (124, 126, 128; 324), at least one first optical signal transmitted by means of a first optical fiber (112; 312) and a second optical signal transmitted by means of a second optical fiber (114; 314). The method (200) further comprises determining (220) at least one signal property of each of the first optical signal and the second optical signal, wherein the signal property is in each case related to an optical fiber behavior of the first and second optical signals, respectively.of the second optical fiber (112, 114; 312, 314), and evaluate (230), by means of a processing device (130; 330), the signal property of the first optical signal and the second optical signal with respect to at least one criterion that indicates the presence of an operating condition of a smoke detector (190; 300) which is suitable to influence a functionality of the smoke detector (190; 300), wherein the at least one operating condition influences the light-guiding behavior of at least one of the first and the second optical fiber (112, 114; 312, 314).The procedure (200) also includes, if the evaluation shows that at least one criterion is met, controlling (240, 242) at least one device function of the smoke detector (190; 300) which relates to the existence of the operating condition and / or the affected functionality of the smoke detector (190; 300), and / or outputting (240, 244) a warning signal which indicates the existence of the operating condition and / or the affected functionality of the smoke detector (190; 300).

Description

[0001] The application relates to a method for operating a smoke detector. The application also relates to a processing device, a system for operating a smoke detector, and a smoke detector. Technical background

[0002] Smoke detectors are traditionally used to detect smoke generated during a fire in fire-prone locations that are not subject to constant human supervision using technical means and to emit a signal indicating the presence of smoke. For this purpose, a smoke detector is usually installed at the location to be monitored, for example, in a room in a building at risk of fire. The signal can be output in the form of an audible alarm, which is emitted by the smoke detector and alerts people within earshot of the alarm to the presence of smoke. The signal can also be output in the form of an optical, electrical, or electromagnetic signal, wirelessly or via a cable, for example, to a central security system of the building in question, to a public fire alarm control center, to a resident's user terminal, etc.The signal can also be transmitted partially via a private or public communications network. In addition to triggering an alarm, smoke detector signals are sometimes also used to initiate technical processes, such as triggering an automatic extinguishing device.

[0003] Smoke detectors contain sensors to detect smoke. Optical measurement methods are usually used. Light is typically emitted from a light source along a test path that runs through a volume of room air. A photosensor is positioned near the test path. If smoke particles enter the test path via the room air, they cause increased absorption and scattering of the emitted light, thereby influencing the light intensity detected by the photosensor. The deviation of the detected light intensity from a reference value corresponding to smoke-free room air serves as a criterion for the assumed presence of smoke.

[0004] In many smoke detectors, the photosensor is located outside the test section. Normally, little or no light from the light source reaches the sensor. When smoke enters the test section, the light is scattered more intensively, partly in the direction of the sensor, which then detects an increased light intensity. In other smoke detectors, the photosensor is located at the end of the test section. Normally, light from the light source reaches the sensor unhindered. In contrast, when smoke enters the test section, the light is absorbed more intensively and scattered away from the direction of the sensor, which then detects a reduced light intensity.

[0005] For reliable operation, optical smoke sensors must be shielded from ambient light as much as possible. In addition, the sensors in smoke detectors are often sensitive to shock and therefore must be protected from mechanical influences. Nevertheless, in order to detect smoke, the sensors must be exposed to the ambient air. Smoke detectors are therefore conventionally equipped with a housing in which the sensors are protected. The housing has at least one opening through which ambient air can enter the housing for measurement by the sensors. This so-called smoke inlet opening(s) is / are chosen to be as small as possible in order to prevent ambient light from entering the measuring area, i.e. the so-called smoke chamber within the housing.A small smoke inlet opening also delays the entry of dust, which typically settles in the smoke chamber over the period of use of the smoke detector and also influences the propagation behavior of the sensor light there, particularly through reflection on the inside of the housing, with increasing dust volume. On the other hand, the smoke inlet opening must be sufficiently large to allow unhindered circulation of ambient air in and out of the smoke chamber and to prevent clogging of the smoke inlet opening, for example by dust, steam, and grease deposits from the ambient air, or at least to delay this clogging beyond the intended use or maintenance interval of the smoke detector. The dimensioning of the smoke inlet opening therefore often represents a compromise between the aforementioned, conflicting requirements.

[0006] For reliable smoke detector operation, the selection of a suitable trigger threshold, which represents the deviation between a current sensor reading and a reference value corresponding to smoke-free room air, is also crucial. On the one hand, the trigger threshold must be sufficiently low to trigger an alarm as early as possible in the event of a fire and also to indicate fires with low smoke development. On the other hand, the trigger threshold must be sufficiently high to avoid false alarms, for example, due to harmless particles such as steam or dust, which are often unavoidably present in the room air. Therefore, determining the trigger threshold also requires a compromise between conflicting requirements.

[0007] The aforementioned criteria are also interdependent in that increasing sensor light scattering due to dust deposition in the smoke chamber over the period of use of the smoke detector means that an increasingly small number of particles in the air can cause the trigger threshold to be exceeded. Therefore, to counteract an increased frequency of false alarms, it is known to adjust the trigger threshold over a period of use of the smoke detector in response to an assumed dust deposition in the smoke chamber.

[0008] The criteria are also interdependent in that progressive clogging of the smoke inlet opening by dust, vapor, and grease deposits from the ambient air over a period of use of the smoke detector can inhibit the entry of smoke into the smoke chamber, thus delaying or even preventing the triggering threshold from being exceeded in the event of a fire. Deposits that can clog the smoke inlet opening of a smoke detector, such as grease mist, depend heavily on the specific operating conditions of the smoke detector. In extreme cases, deposits in the area of the smoke inlet opening can completely stop the smoke detector from functioning. Furthermore, since clogging of the smoke inlet opening does not promote the occurrence of false alarms, but rather leads to a lack of alarms, a clogged smoke inlet opening on a smoke detector can go unnoticed for a long time.

[0009] To counteract this, it is known to attach an uncovered light guide outside the smoke chamber to the housing of the smoke detector. A test light is passed through the light guide, the intensity of which is measured after it has passed through the light guide. It is assumed that deposits from the ambient air, which can clog the smoke inlet opening, also deposit on the surface of the light guide. There, the deposits cause a change in the light conducting behavior of the light guide, as they typically have a higher refractive index than air. In particular, the deposits increase the coupling out of light from the light guide at the respective point of contact with the light guide surface, so that the amount of light that completely passes through the light guide and thus the measured light intensity at the output of the light guide is reduced, corresponding to a reduced transmission rate of the light guide.The measured light intensity at the output of the fiber optic cable allows conclusions to be drawn about the extent to which the smoke detector's smoke inlet opening is blocked. This can then be used to determine whether the smoke detector requires maintenance or to adjust the smoke detector's sensitivity, i.e., the trigger threshold.

[0010] EP 3 113 133 A2 relates to a smoke detector with combined cover and particle detection of the smoke inlet opening. It describes at least one transmitting diode arranged in the housing, the transmission signals of which are conducted through at least one transparent light-conducting medium to at least one receiving diode, which is provided to receive the transmission signals from the at least one transmitting diode. Furthermore, it is described that the light-conducting medium encloses the smoke inlet opening in the housing, wherein a change in the received transmission signals at the receiving diodes is used to conclude that the smoke inlet opening in the housing is at least partially covered and / or that particles are present in the smoke inlet opening in the housing, and a warning signal is generated.

[0011] In practice, it has been shown that the light conduction behavior of an unclad fiber optic cable during the typical service life of a smoke detector is influenced by factors other than deposits. Depending on the location, climate and weather conditions can have very different effects on the surface of the fiber optic cable and cause it to corrode to varying degrees, which can also lead to increased light extraction from the fiber optic cable and increased light scattering within the fiber optic cable. Furthermore, because the fiber optic cable is mounted outside the smoke chamber for its intended purpose, it is subject to increased mechanical, chemical, or other external influences. These can occur unnoticed in individual cases.For example, if the light guide is located on the side of the housing, a piece of painter's tape that is accidentally left on the housing and touches the light guide can significantly impair its function and lead to false assumptions about the smoke inlet opening of the smoke detector being blocked.

[0012] It is therefore desirable to have a technology that avoids or at least mitigates the aforementioned disadvantages. Summary of the invention

[0013] This object is achieved by a method according to claim 1, a processing device according to claim 13, a system according to claim 14 and a smoke detector according to claim 15.

[0014] The invention is defined in the independent claims. The dependent claims contain advantageous developments of the invention.

[0015] According to a first aspect, a method for operating a smoke detector is presented. The method comprises detecting, by means of at least one sensor device, at least one first optical signal transmitted by means of a first optical fiber, and a second optical signal transmitted by means of a second optical fiber. The method further comprises determining at least one signal property of each of the first optical signal and the second optical signal, wherein the signal property is in each case attributable to an optical fiber behavior of the first or second optical fiber.of the second optical fiber, and evaluating, by means of a processing device, the signal property of the first optical signal and the second optical signal with respect to at least one criterion that indicates the presence of an operating condition of a smoke detector that is suitable for influencing a functionality of the smoke detector, wherein the at least one operating condition influences the light conducting behavior of at least one of the first and the second optical fiber. The method also comprises, if the evaluation shows that the at least one criterion is met, controlling at least one device function of the smoke detector that is related to the presence of the operating condition and / or the influenced functionality of the smoke detector, and / or outputting an indication signal that indicates the presence of the operating condition and / or the influenced functionality of the smoke detector.

[0016] By providing the first and second optical fibers, the reliability and accuracy of an evaluation result with respect to the at least one operating condition can be improved. The provision of the first and second optical fibers also allows for differentiation between different operating conditions of the smoke detector.

[0017] The smoke detector may comprise the at least one sensor device, the first optical fiber, the second optical fiber and / or the processing device.

[0018] The at least one signal property can be determined by means of the sensor device and / or the processing device. Furthermore, the indication signal can be output by means of the processing device.

[0019] The first light guide and the second light guide can be arranged outside a smoke chamber of the smoke detector.

[0020] The first light guide and the second light guide can be uncovered or transparently covered at least in sections.

[0021] At least one of the first light guide and the second light guide can be curved in a plane of the smoke detector. The second light guide can be curved in the plane of the smoke detector and at least partially surround the first light guide with respect to the plane. Additionally or alternatively, the second light guide can be curved in the plane of the smoke detector and at least partially form or surround a boundary of the smoke detector.

[0022] As a result, possible operating conditions of the smoke detector that act on the smoke detector from a lateral direction, in particular lateral impacts, the lateral application of paint or adhesive objects, and / or an influx of chemical substances from a lateral direction, can also act on at least one of the first and second optical fibers. This facilitates the determination of such operating conditions based on the detected first and second optical signals.

[0023] The first light guide and the second light guide can differ with respect to a light guide material, a coating, a light guide geometry, and / or an arrangement relative to a boundary, a housing, and / or a smoke chamber of the smoke detector. As a result, different possible operating conditions of the smoke detector can influence the light conduction behavior of the first light guide and the second light guide differently. This facilitates differentiation between the different possible operating conditions based on the detected first and second optical signals.

[0024] The first optical signal and the second optical signal can be generated by means of at least one light source of the smoke detector.

[0025] The signal property can comprise an intensity of the respective optical signal. The at least one criterion can comprise an exceeding or falling below a threshold difference between an intensity of the first optical signal and an intensity of the second optical signal. The at least one signal property can, in particular, comprise a maximum or an average light intensity of the respective optical signal in at least one light wavelength range.

[0026] The at least one criterion may be temporally variable according to a predetermined rule.

[0027] The at least one operating condition can influence the light conducting behavior of at least one of the first and second light guides at least partially by influencing a transmission rate in at least one region of a lateral surface of the respective light guide.

[0028] According to a further aspect, a processing device is presented. The processing device comprises at least one processor unit, and at least one memory device operatively connected to the processor unit and containing portions of program code that, when executed by the processor unit, configures the processing device to perform the following steps: receiving, from at least one sensor device, at least one first sensor signal indicative of a first optical signal detected by the sensor device, and a second sensor signal indicative of a second optical signal detected by the sensor device, and determining at least one signal property of each of the first optical signal and the second optical signal, or receiving, from the at least one sensor device, at least one first sensor signal,which indicates at least one signal property of the first optical signal detected by the sensor device, and a second sensor signal which indicates at least one signal property of the second optical signal detected by the sensor device, wherein the first optical signal is transmitted by means of a first optical fiber and the second optical signal is transmitted by means of a second optical fiber, and the signal property each indicates a light-guiding behavior of the first and second optical fibers, respectively; evaluating the signal property of the first optical signal and the second optical signal with respect to at least one criterion indicating the presence of an operating condition of a smoke detector that is capable of influencing a functionality of the smoke detector, wherein the at least one operating condition influences the light-guiding behavior of at least one of the first and second optical fibers,and if the evaluation shows that the at least one criterion is met, controlling at least one device function of the smoke detector that is related to the presence of the operating condition and / or the affected functionality of the smoke detector, and / or outputting an indication signal that indicates the presence of the operating condition and / or the affected functionality of the smoke detector.

[0029] According to a further aspect, a system for operating a smoke detector is presented. The system comprises a processing device of the type presented here. The system also comprises at least one light source configured to generate at least a first optical signal and a second optical signal, at least one first optical fiber configured to transmit the first optical signal and a second optical fiber configured to transmit the second optical signal, and at least one sensor device operatively connected to the processing device and configured to detect the first optical signal and the second optical signal.

[0030] According to a further aspect, a smoke detector is presented. The smoke detector comprises a processing device of the type presented here. The smoke detector also comprises at least one light source configured to generate at least a first optical signal and a second optical signal, at least one first optical fiber configured to transmit the first optical signal and a second optical fiber configured to transmit the second optical signal, and at least one sensor device operatively connected to the processing device and configured to detect the first optical signal and the second optical signal. Short description of the drawings

[0031] Further features, advantages, and objects of the invention will become apparent from the drawings and the detailed description. They show: Fig. 1 shows a system for operating a smoke detector according to one example; Fig. 2 shows a flowchart of a method for operating a smoke detector according to another example; and Fig. 3 shows a smoke detector according to another example. Detailed description

[0032] Fig. 1 shows schematically and exemplarily a system 100 for operating a smoke detector 190. The system 100 comprises a first light guide 112 and a second light guide 114, each of which is arranged outside a smoke chamber 192 of the smoke detector 190.

[0033] The smoke detector 190 is in some versions part of the system 100. As indicated by the dashed lines in Fig. 1As indicated, in other embodiments of the system 100, the smoke detector 190 is not part of the system 100. The system 100 is, for example, in operative communication with the smoke detector 190. In some embodiments in which the system 100 is designed separately from the smoke detector 190, the system 100 is not directly connected to the smoke detector 190. The system 100 is designed, for example, to communicate with a control center (not shown), which also receives signals from the smoke detector 190 and evaluates them depending on signals from the system 100.

[0034] The system 100 comprises a light source 120. The light source 120 is arranged such that an optical signal generated by the light source 120 can be coupled into the first optical fiber 112 and the second optical fiber 114. The system 100 also comprises a sensor device 124. The sensor device 124 is configured to detect optical signals generated by the light source 120 and coupled into the first optical fiber 112 or the second optical fiber 114 after passing through the respective first optical fiber 112 or second optical fiber 114. In the example shown, the sensor device 124 comprises a first sensor 126 assigned to the first optical fiber 112 and a second sensor 128 assigned to the second optical fiber 114.

[0035] In other examples, the sensor device 124 comprises a common sensor for the first and second optical fibers 112, 114. To distinguish between the optical signals transmitted by the first and second optical fibers 112, 114, means are provided, for example, to selectively couple optical signals into only one of the first and second optical fibers 112, 114 at different times. Instead of the common light source 120, an independently controllable light source is provided for each of the optical fibers 112, 114, for example.

[0036] The system 100 further includes a processing device 130. The processing device 130 includes a processor unit 140 and a memory device 150 operatively connected to the processor unit 140. The processing device 130 is connected to the light source 120 and the sensor device 124 via interfaces 132, 134. In the example shown, the processing device 130 further includes a communication module 160 operatively connected to the processor unit 140. The communication module 160 serves, for example, to transmit signals, either wirelessly or via a cable, to a control center.

[0037] The smoke detector 190 comprises a smoke chamber 192, into which ambient air can enter through a smoke inlet opening 194. A smoke sensor 196 of the smoke detector 190 is arranged in the smoke chamber 192. The smoke sensor 196 is operatively connected to a control unit 198 of the smoke detector 190. The smoke sensor 196 is designed to detect the presence of smoke in the smoke chamber 192. The detection takes place, for example, optically. The smoke sensor 196 is also designed to output a signal to the control unit 198 indicating a detected presence of smoke in the smoke chamber 192. The control unit 198 evaluates the signal received from the smoke sensor 196 with respect to a trigger criterion, for example, a threshold concentration of smoke in the smoke chamber 192, and generates a smoke detector signal depending on the evaluation result.

[0038] The system 100 is primarily intended to allow conclusions to be drawn about a possible clogging of the smoke inlet opening 194 as a result of deposits from the ambient air, for example steam, dust or grease mist. For this purpose, at least one of the first and second light guides 112, 114 is designed such that deposits from the ambient air that can clog the smoke inlet opening 194 also occur on the corresponding first or second light guide 112, 114 and influence the light conduction behavior of the respective light guide 112, 114. For this purpose, the respective light guide 112, 114 is designed, for example, to be unclad, i.e., without an opaque sheath, and is arranged at least in sections outside a housing of the smoke detector 190 or in an open area of a housing of the smoke detector 190.

[0039] Deposits, such as steam, dust, or grease mist in the ambient air, that occur on a surface of the respective optical fiber 112, 114 typically have a higher refractive index than smoke-free air. These deposits thus reduce the reflection rate of the light that hits the surface from within the respective optical fiber. This leads to increased coupling of light from the optical fiber, which is therefore no longer detected at an output end of the optical fiber by the sensor device 124.The system 100 thus allows the determination of a light conducting behavior, including possible impairments of the light conducting behavior, for the respective light guide 112, 114 by detecting a light intensity at an output end of the respective light guide 112, 114 by means of the sensor device 124 and by evaluating the detected light intensity in relation to a light intensity coupled into the respective light guide 112, 114 by means of the light source 120. Based on the determined light conducting behavior, it is possible to infer deposits on the surface of the light guide and thus corresponding deposits in the area of the smoke inlet opening 194 of the smoke detector 190.

[0040] As in Fig. 1As shown schematically, the first and second light guides 112, 114 are curved. A non-straight geometry of the light guides 112, 114 increases the frequency of light reflection on the outer surface of the respective light guide and thus the influence of light reflection on the light conduction in the light guide. An increased coupling of light from the light guide as a result of deposits on the outside of the light guide is thus easier to measure. In the example shown, the first and second light guides 112, 114 also surround the smoke detector 190 in a plane of the smoke detector 190. This ensures that deposits that primarily reach the smoke detector 190 from a certain direction are not shielded from the first and second light guides 112, 114 by a housing of the smoke detector 190.

[0041] In a simple example of system 100, the first and second optical fibers 112, 114 are equally configured to determine a light conduction behavior of the first and second optical fibers 112, 114, respectively. For example, an optical signal generated by the light source 120 is coupled equally into the first optical fiber 112 and the second optical fiber 114, and its intensity is detected by the sensor device 124 after passing through the respective optical fiber. The respectively detected intensity is evaluated by the processor unit 140 of the processing device 130 with respect to an operating condition of the smoke detector 190.

[0042] An operating condition of the smoke detector 190 corresponds in one case to a quantity of deposits from the ambient air of the smoke detector 190. If the optical conduction behavior of both the first and second optical fibers 112, 114 indicates an equal or similar degree of impairment, the processing device 130 concludes that deposits from the ambient air on the optical fiber 112, 114 are the cause of the impairment. The respective evaluation results based on the optical signal from the first and second optical fibers 112, 114 can be averaged to more reliably determine the amount of deposits.

[0043] If, however, there is a significant difference between the first optical fiber and the second optical fiber 112, 114 with regard to impaired optical conduction behavior, a different or additional operating condition of the smoke detector is inferred by means of the processing device 130. Possible causes for a different impairment of the optical conduction behavior of the optical fibers 112, 114 include, for example, mechanical damage to one of the optical fibers 112, 114, mechanical and / or optical shadowing of one of the optical fibers 112, 114, for example, due to paint or adhesive tape adhering to the respective optical fiber, increased corrosion of one of the optical fibers 112, 114 due to chemical or climatic influences acting unevenly on the optical fibers 112, 114, etc.

[0044] The evaluation of the intensity of the optical signal after passing through the first and second optical fibers 112, 114 for the presence of a specific operating condition of the smoke detector 190 occurs with reference to one or more criteria that indicate the presence of the respective operating condition. The criteria include a difference between an impairment of the optical conductivity of the first and second optical fibers 112, 114 compared to a standard value of the optical conductivity of the respective optical fiber 112, 114. The criteria additionally include a temporal change in the optical conductivity of the first or second optical fiber 112, 114 compared to a previously determined optical conductivity of the respective first or second optical fiber 112, 114.The temporal change is determined, for example, by comparison with logged data of a light conducting behavior of the first and second light guides 112, 114 from previous measurements or evaluations by means of the system 100.

[0045] The evaluation by the processing device 130 is carried out with regard to whether the determined operating condition of the smoke detector 190 is likely to impair the functionality of the smoke detector 190. If the evaluated light conduction behavior of the first and second light guides 112, 114 indicates, for example, uniform deposits from the ambient air in the area of the smoke detector 190, and if the deposits are of a size that corresponds to a blockage of the smoke inlet opening 194 to such an extent that the functionality of the smoke detector 190 is not guaranteed, the processing device 130 outputs, for example, an advisory signal via the communication module 160 to a control center. The advisory signal serves, for example, to indicate a maintenance requirement for the smoke detector 190.

[0046] In other examples, if the evaluated light conducting behavior of the first and second light guides 112, 114 indicates uniform deposits to an extent that inhibits the entry of ambient air into the smoke chamber 192 through the smoke inlet opening 194, but does not endanger the function, the processing device 130 outputs a control signal via an interface 136 to the control unit 198 of the smoke detector 190. The control signal causes, for example, that a triggering threshold value of the smoke detector 190 is lowered in order to avoid a delayed output of a smoke detector signal due to a delayed entry of the ambient air into the smoke chamber in the event of a fire.

[0047] In some examples, if a significant deviation is detected between the impairments of the optical conduction behavior of the first and second optical fibers 112, 114, an indication signal is output to a control center by means of the processing device 130. The indication signal serves, for example, to indicate, regardless of a specific operating condition of the smoke detector 190, that conclusions regarding a blockage of the smoke inlet opening 194 based on the optical conduction behavior of the first or second optical fibers 112, 114 are currently not sufficiently reliable and that, therefore, for example, maintenance of the smoke detector 190 or the system 100 is required.

[0048] As is clear from the preceding examples, the provision of the first optical fiber 112 and the second optical fiber 114 allows for improved reliability in the evaluation of a determined signal property of an optical signal transmitted by the first and second optical fibers 112, 114, respectively, with respect to an assumed operating condition of the smoke detector 190. The provision of the first optical fiber 112 and the second optical fiber 114 also allows for improved differentiation between various possible operating conditions of the smoke detector 190, at least insofar as such an operating condition affects a light-guiding behavior of at least one of the first and second optical fibers 112, 114.

[0049] In some examples of the system 100, the possibility of verifying the plausibility of an evaluation result of the optical fiber behavior of the first and second optical fibers 112, 114 with respect to an operating condition is further facilitated by logging signals from the sensor device 124 and / or evaluation results from the processing device 130 in a storage device 150 of the processing device 130. This allows an evaluation of the signal properties of optical signals additionally with respect to a temporal change, for example, a temporal change in the optical fiber behavior of each of the first and second optical fibers 112, 114. This makes it possible to distinguish between continuous processes, such as the continuous deposition of particles from the ambient air, and acute events, such as mechanical damage to one of the optical fibers 112, 114 or obscuration of one of the optical fibers 112, 114 due to manipulation.

[0050] In some examples of the system 100, the possibility of verifying and distinguishing between different possible operating conditions of the smoke detector 190 is further enhanced by the first and second light guides 112, 114 having different geometries and / or comprising different materials that have different light conduction properties or are differently resistant to corrosion, etc. This is Fig. 1indicated by different hatching of the first and second optical fibers 112, 114. Different operating conditions therefore have different effects, for example, on the optical conduction behavior of the first and second optical fibers 112, 114, respectively. As a result, such operating conditions can be differentiated based on the optical conduction behavior of the first and second optical fibers 112, 114, and, depending on the respective operating condition, a device function of the smoke detector 190 can be appropriately controlled or an advisory signal can be appropriately output.

[0051] As in Fig. 1As shown by the dashed lines, in some examples the smoke detector 190 is formed separately from the system 100. In other examples, however, the smoke detector 190 also includes some or all of the features of the system 100 described above. In examples where the smoke detector 190 includes some of the aforementioned features of the system 100, the smoke detector is in operative communication with the remaining components of the system 100 not included in the smoke detector 190, for example, to operate these features. In particular, in some examples the smoke detector 190 includes the first and second light guides 112, 114, which are attached, for example, to a housing of the smoke detector 190 to form a lateral boundary of the smoke detector 190.

[0052] Fig. 2shows a flowchart of a method 200 for operating a smoke detector. The method 200 is implemented by means of a system 100 as described in connection with Fig. 1 described, and for operating a smoke detector, such as the smoke detector 190 in Fig. 1 , feasible. In some examples, the smoke detector is part of the system. In other examples, the method 200 is carried out by means of a system for operating a smoke detector, wherein the smoke detector itself is not part of the system, as in connection with Fig. 1 described.

[0053] The method 200 comprises detecting, using at least one sensor device, at least one first optical signal and at least one second optical signal. The first optical signal is transmitted via a first optical fiber, and the second optical signal is transmitted via a second optical fiber, step 210. The method 200 further comprises determining at least one signal property of each of the first optical signal and the second optical signal. The signal property indicates a light-guiding behavior of the first and second optical fibers, step 220.

[0054] Method 200 further includes evaluating the signal properties of the first optical signal and the second optical signal with respect to at least one criterion. The criterion indicates the presence of an operating condition of the smoke detector in question that is capable of influencing a functionality of the smoke detector. The at least one operating condition simultaneously influences the optical conduction behavior of at least one of the first and second optical fibers, step 230.

[0055] If the evaluation shows that the at least one criterion is met, in some examples, the control of at least one device function of the smoke detector takes place in a subsequent step 240 according to the method 200. The device function is related to the presence of the operating condition and / or the affected functionality of the smoke detector, sub-step 242. With reference to the example in Fig. 1The control of a device function of the smoke detector 190 takes place, for example, in implementations in which the processing device 130 is operatively connected directly to a control unit 198 of the smoke detector 190 via the interface 136. In further examples, in step 240, an indication signal is output, which indicates the presence of the operating condition and / or the affected functionality of the smoke detector, sub-step 244. With reference to the example in Fig. 1 The warning signal is output via a communication module 160 of the processing device 130, by radio or via a line, for example to a control center.

[0056] In some examples of the method 200, both substeps 242, 244 are performed. In other examples of the method 200, only one of the substeps 242, 244 is performed in conjunction with step 240.

[0057] Fig. 3shows schematically and exemplarily a smoke detector 300. The smoke detector 300 comprises a smoke chamber 392, which is arranged in a housing of the smoke detector 300 and can enter the ambient air through a smoke inlet opening 394 of the smoke detector 300. A smoke sensor 396 is arranged in the smoke chamber 392. The functioning of these features of the smoke detector 300 is governed by the principles of the invention described in connection with the smoke detector 190 in Fig. 1 Described accordingly.

[0058] The smoke detector 300 also comprises a first optical fiber 312 and a second optical fiber 314, each arranged outside the smoke chamber 392. An optical signal can be coupled into each of the first and second optical fibers 312, 314 by means of at least one light source 320, 322. An optical signal transmitted by means of the first or second optical fiber 312, 314 can be detected by means of a sensor device 324. Sensor signals from the sensor device 324 are output to a processing device 330. The functioning of the first optical fiber 312, the second optical fiber 314, the at least one light source 320, 322, the sensor device 324 and the processing device 330 is also subject to the Fig. 1 Described accordingly, as far as Fig. 3 and the following description does not indicate anything different.

[0059] Deviating from the example in Fig. 1In the case of the smoke detector 300, the aforementioned features are components of the smoke detector 300. In the case of the smoke detector 300, the processing device 330 also serves simultaneously as a control unit of the smoke detector 300, similar to the control unit 198 of the smoke detector 190 in Fig. 1 . Furthermore, deviating from the example in Fig. 1In the smoke detector 300, each of the first smoke detector 312 and the second smoke detector 314 is assigned a light source 320, 322, which can be controlled independently of one another by means of the processing device 330. In contrast, in the smoke detector 300, a common sensor device 324 is provided for both the first optical fiber 312 and the second optical fiber 314. A distinction between an optical signal transmitted by the first optical fiber 312 and an optical signal transmitted by the second optical fiber 314 is made, for example, by means of different sensor regions of the sensor device 324. In other examples, the signals are differentiated by controlling the light sources 320, 322 at different times.

[0060] The smoke detector 300 is different from the system 100 Fig. 1represents a fully integrated implementation. All functionalities of the system 100 are integrated into the smoke detector 300. When the method 200 is carried out using the smoke detector 300, for example, the evaluation of the signal properties of the optical signals transmitted by the first and second optical fibers 312, 314 and the subsequent control and implementation of a device function of the smoke detector 300 are all carried out within the processing device 330.

[0061] In other than the illustrated example of the smoke detector 300, this comprises, similar to the example of Fig. 1, a common light source for the first and second optical fibers 312, 314. A distinction between the signals is made, for example, on the sensor side, for example by means of different sensors assigned to the first and second optical fibers 312, 314, respectively. In other examples, a distinction is made between optical signals transmitted through the first and second optical fibers 312, 314, respectively, and detected by sensors, in another way, for example by using suitable color filters.

[0062] The aforementioned examples are aimed at verifying and distinguishing between different operating conditions of a smoke detector by providing and appropriately operating a first optical fiber and a second optical fiber. However, it is understood that the described techniques can also be advantageously used for different applications and in connection with operating conditions other than those described.

Claims

1. Method (200) of operating a smoke detector (190; 300) comprising: detecting (210), by means of at least one sensor device (124, 126, 128; 324), at least a first optical signal transmitted by means of a first light guide (112; 312) and a second optical signal transmitted by means of a second light guide (114; 314); determining (220) at least one signal characteristic of each of the first optical signal and the second optical signal, wherein the signal characteristic respectively indicates a light-guiding behavior of the first or the second light guide (112, 114; 312, 314); evaluating (230), by means of a processing device (130; 330), the signal characteristic of the first optical signal and of the second optical signal with respect to at least one criterion which indicates the presence of an operating condition of a smoke detector (190; 300) which is adapted to influence a functionality of the smoke detector (1 90; 300), wherein the at least one operating condition influences the light-guiding behavior of at least one of the first and the second light guide (112, 114; 312, 314); and, if the evaluation shows that the at least one criterion is met, controlling (240, 242) of at least one device function of the smoke detector (190; 300), which is related to the presence of the operating condition and / or the influenced functionality of the smoke detector (190; 300), and / or outputting (240, 244) an indication signal indicating the presence of the operating condition and / or the affected functionality of the smoke detector (190; 300), wherein: the at least one criterion comprises a difference between an impairment of the light-guiding behavior of the first and the second light guide (112, 114; 312, 314) with respect to a standard value of the light-guiding behavior of the respective light guide (112, 114; 312, 314), and the evaluation (230) is carried out with regard to whether the difference indicates an equal or similar degree of impairment of the light-guiding behavior of the first and the second light guide (112, 114; 312, 314), wherein the steps further comprise: if the evaluation (230) indicates an equal or similar degree of impairment, concluding, by means of the processing means (130; 330), that deposits from the ambient air are present, as the at least one operating condition, and, if the evaluating (230) does not indicate an equal or similar degree of impairment, concluding, by means of the processing means (130; 330), that another or additional operating condition is present, which is different from deposits from the ambient air, as the at least one operating condition.

2. Method according to claim 1, wherein the smoke detector (190; 300) comprises the at least one sensor device (124, 126, 128; 324), the first light guide (112; 312), the second light guide (114; 314) and / or the processing device (130; 330).

3. Method according to claim 1 or 2, wherein determining (220) the at least one signal characteristic is carried out by means of the sensor device (124, 126, 128; 324) and / or the processing device (130; 330), and the output (240, 244) of the indication signal is carried out by means of the processing device (130; 330).

4. Method according to any one of the preceding claims, wherein the first light guide (112; 312) and the second light guide (114; 314) are arranged outside a smoke chamber (192; 392) of the smoke detector (190; 300), and / or wherein the first light guide (112; 312) and the second light guide (114; 314) are at least in sections uncovered or have a transparent covering.

5. Method according to any one of the preceding claims, wherein at least one of the first light guide (112; 312) and the second light guide (114; 314) is curved in a plane of the smoke detector (190; 300).

6. Method according to claim 5, wherein the second light guide (114; 314) is curved in the plane of the smoke detector (190; 300) and at least partially surrounds the first light guide (112; 312) with respect to the plane.

7. Method according to claim 5 or 6, wherein the second light guide (114; 314) is curved in the plane of the smoke detector (190; 300) and at least in sections forms or surrounds a boundary of the smoke detector (190; 300).

8. Method according to any one of the preceding claims, wherein the first light guide (112; 312) and the second light guide (114; 314) are different with respect to a light guide material, a coating, a light guide geometry and / or an arrangement relative to a boundary, a housing and / or a smoke chamber (192; 392) of the smoke detector (190; 300).

9. Method according to any one of the preceding claims, wherein the first optical signal and the second optical signal are generated by means of at least one light source (120; 320, 322) of the smoke detector (190; 300).

10. Method according to any one of the preceding claims, wherein the signal characteristic comprises an intensity of the respective optical signal and the at least one criterion comprises exceeding or falling below a threshold value difference between an intensity of the first optical signal and an intensity of the second optical signal.

11. Method according to any one of the preceding claims, wherein the at least one criterion is variable over time in accordance with a predetermined rule.

12. Method according to any one of the preceding claims, wherein the at least one operating condition influences the light-guiding behavior of at least one of the first and the second light guide (112, 114; 312, 314) at least partially by influencing a transmission rate in at least one area of a lateral surface of the respective light guide (112, 114; 312, 314).

13. Processing device (130; 330) comprising: at least one processing unit (140); and at least one memory device (150) operatively connected to said processing unit (140) and comprising parts of program code which, when executed by means of said processing unit (140), configures the processing device (130; 330) to execute the following steps: receiving (210), from at least one sensor device (124, 126, 128; 324), at least a first sensor signal indicating a first optical signal detected by the sensor device (124, 126, 128; 324) and a second sensor signal indicating a second optical signal detected by the sensor device (124, 126, 128; 324), and determining (220) at least one signal characteristic of each of the first optical signal and the second optical signal; or receiving, from the at least one sensor device (124, 126, 128; 324), at least a first sensor signal indicating at least one signal characteristic of the first optical signal detected by the sensor device (124, 126, 128; 324) and a second sensor signal indicating at least one signal characteristic of the second optical signal detected by means of the sensor device (124, 126, 128; 324), wherein the first optical signal is transmitted by means of a first light guide (112; 312) and the second optical signal is transmitted by means of a second light guide (114; 314), and wherein the signal characteristic indicates a light-guiding behavior of the first or the second light guide (112, 114; 312, 314); evaluating (230) the signal characteristic of the first optical signal and of the second optical signal with respect to at least one criterion indicating the presence of an operating condition of a smoke detector (190; 300) adapted to influence a functionality of the smoke detector (190; 300), wherein the at least one operating condition influences the light-guiding behavior of at least one of the first and the second light guide (112, 114; 312, 314); and if the evaluation shows that the at least one criterion is met, controlling (240, 242) at least one device function of the smoke detector (190; 300) which is related to the presence of the operating condition and / or the influenced functionality of the smoke detector (190; 300), and / or outputting (240, 244) an indication signal which indicates the presence of the operating condition and / or the influenced functionality of the smoke detector (190; 300), wherein: the at least one criterion comprises a difference between an impairment of the light-guiding behavior of the first and the second light guide (112, 114; 312, 314) with respect to a standard value of the light-guiding behavior of the respective light guide (112, 114; 312, 314), and the evaluation (230) is carried out with regard to whether the difference indicates an equal or similar degree of impairment of the light-guiding behavior of the first and the second light guide (112, 114; 312, 314), said steps further comprising: if said evaluating (230) indicates an equal or similar level of impairment, concluding, by means of said processing means (130; 330), that deposits from ambient air have occurred, as the at least one operating condition, and, if the evaluating (230) does not indicate an equal or similar level of impairment, concluding, by means of the processing device (130; 330), that a different or additional operating condition, which is different from deposits from the ambient air, has occurred, as the at least one operating condition.

14. System (100) for operating a smoke detector, comprising: a processing device (130) according to claim 13; at least one light source (120) configured to generate at least a first optical signal and a second optical signal; at least a first light guide (112) configured to transmit the first optical signal and a second light guide (114) configured to transmit the second optical signal; and at least one sensor device (124, 126, 128) operatively connected to the processing device (130) and configured to detect the first optical signal and the second optical signal.

15. Smoke detector (300) comprising: a processing device (330) according to claim 13; at least one light source (320, 322) configured to generate at least a first optical signal and a second optical signal; at least a first light guide (312) configured to transmit the first optical signal and a second light guide (314) configured to transmit the second optical signal; and at least one sensor device (324) operatively connected to the processing means (330) and configured to detect the first optical signal and the second optical signal.

Images