LIGHT GUIDE ARRANGEMENT, SPARK AND / OR FLAME DETECTOR AND FIRE PROTECTION SYSTEM

Description

[0001] The present invention relates to a light guide arrangement for transmitting electromagnetic radiation, a spark and / or flame detector, a fire protection system and an associated method.

[0002] Spark and flame detectors are well-known. Also referred to as spark detectors and flame detectors, they are frequently used in fire protection systems that detect sparks and / or flames and, preferably upon detection, activate an extinguishing agent dispensing device and / or a protective device via a central control unit. A known method for detecting sparks or flames is to detect the characteristic electromagnetic radiation they generate. The radiation emitted by sparks has characteristic wavelengths in the range of approximately 0.2 to 2 micrometers, while that emitted by flames has several wavelengths in the range of 0.2 to 6 micrometers. Furthermore, embers that exhibit characteristic radiation from sparks and / or flames are also referred to as sparks.

[0003] The problem is that the areas to be monitored, where sparks or flames need to be monitored, are often exposed to very high temperatures, for example 450°C, which is outside the operating temperature range of typical detectors, which regularly ends at a maximum of 125°C.

[0004] Examples of applications for spark and / or flame detectors, as well as fire protection systems, in environments with such demanding conditions include pneumatic conveyors in material dryers for, for example, grain or wood chips, where foreign particles such as stones could trigger sparks. Of course, other comparable applications are also conceivable, such as drying chambers / ovens where materials could ignite, or other manufacturing processes, objects, or rooms where sparks, embers, or flames could occur. In this context, spark and / or flame detectors are also referred to synonymously as spark and / or flame alarms.

[0005] The German Patent and Trademark Office has searched the following prior art in the priority application for the present application: DE 30 42 399 A1, DE 30 42 454 A1, DE 20 2013 006 142 U1, DE 691 24 165 T2 and US 4,592,353 A.

[0006] US 2007 / 223000 A1 describes an optical sensor with a sapphire body. A cavity in the sapphire body defines a surface that serves as the surface of a Fabry-Perot resonator. Interferometry is used to detect changes in the length of the Fabry-Perot resonator and thus changes, for example, in the temperature or pressure of the environment in which the sensor is located.

[0007] DE 30 42 399 A1 comprises a sensor arrangement for detecting physical processes in the combustion chamber of an internal combustion engine. The sensor arrangement includes at least one optical fiber facing the combustion chamber, arranged in a preferably spark plug-like screw housing. According to the invention, the optical fiber is designed as a quartz glass rod, which is supported on the combustion chamber side by an inner shoulder of the housing and on the side facing away from the combustion chamber by a flange adapted to the housing.

[0008] DE 30 42 454 A1 describes a sensor arrangement for detecting physical processes in the combustion chamber of an internal combustion engine. The sensor is preferably arranged in a spark plug-like screw housing and has a light guide facing the combustion chamber. The light guide is designed as a quartz glass rod, which is arranged coaxially with a fused window located on the side of the sensor facing away from the combustion chamber. The sensor can advantageously be used to measure the knocking of an internal combustion engine.

[0009] DE 602 13 083 T2 also relates to a device for arranging a photoelectric converter on a component for processing electrical signals.

[0010] DE 10 2015 223362 A1 relates to an explosion-proof enclosure for means of transmitting or receiving electromagnetic radiation. The enclosure comprises a housing body designed to accommodate such transmitting and / or receiving means, and a window element with a first side facing the interior of the enclosure and a second, opposite side facing away from the interior of the enclosure, wherein the window element is transparent to electromagnetic radiation. The housing body has a crimp on the second side of the window element, which presses the window element towards a seat formed inside the enclosure, so that the enclosure is designed as a pressure-resistant enclosure and / or as a dust-tight enclosure.

[0011] CN 1 112 026 A describes an air-cooled housing for a light therapy device, comprising a handle integrated into the housing. Support points for the light therapy device are evenly spaced on the inner wall of the housing, leaving a gap and a channel for air circulation between the inner wall of the housing and the outer wall of the lamp compartment of the light therapy device. The outer wall of the light guide has a double-layered sleeve structure. An exhaust vent is provided at the end of the light source closest to the housing, to which an electric exhaust fan is attached. An air inlet is provided at the far end of the housing opposite the exhaust fan.

[0012] JP H10 106317 A describes a sunlight auto-tracking device comprising a main sensor arranged on an outer circumference of a concentrator, a concentrator inner sensor arranged inside the concentrator, wherein the main sensor, the concentrator inner sensor and a fine-adjustment sensor interact for fine-tuning the focus, wherein the fine-adjustment sensor consists of an upward fine-adjustment sensor, a downward fine-adjustment sensor and a stop-tracking fine-adjustment sensor, wherein the stop-tracking fine-adjustment sensor is arranged between a heat-resistant optical fiber for the upward fine-adjustment sensor and a heat-resistant optical fiber for the downward fine-adjustment sensor and is positioned in a direction perpendicular to the forward direction of the horizontal rotation of the concentrator, and wherein a heat-resistant optical fiber shielding tube,which serves to guide the light to the stop-tracking fine-adjustment sensor, is provided with a slot.

[0013] Against this background, the task was to provide a light guide arrangement, a spark and / or flame detector, as well as fire protection systems and associated procedures that enable sparks or flames arising in demanding environmental conditions to be detected with high reliability.

[0014] According to the invention, the problem is solved by a light guide arrangement for transmitting electromagnetic radiation, in particular ultraviolet and / or infrared radiation, according to claim 1, wherein the light guide arrangement comprises a housing and a light guide rod, wherein the housing has a light inlet opening and an opposite light outlet opening, wherein the light guide rod is arranged in the housing between the light inlet opening and the light outlet opening, wherein the light guide rod is resiliently mounted on at least one side in the housing in order to absorb different thermal expansions between the light guide rod and the housing as well as shocks to the light guide rod.

[0015] An air gap is provided between the light guide rod and the housing, particularly along the axial direction of the light guide rod, with the air gap preferably being between 0.2 mm and 5 mm. In particular, the air gap is provided circumferentially around the entire light guide rod. The air in the air gap assists in cooling the light guide assembly.

[0016] The light guide arrangement also includes an air inlet device designed to introduce air, in particular compressed air, into the air gap between the light guide rod and the housing.

[0017] This provides a light guide assembly that includes a spring-mounted light guide rod, thus enabling it to withstand shocks and differing thermal expansion between the light guide rod and the housing. This ensures continued operation even with significant temperature differences between the light entry and exit apertures, without causing stress in the light guide assembly. Typically, the light guide is fragile and is protected by the spring-mounted assembly according to the invention.

[0018] The spring-loaded or oscillating mounting is particularly advantageous because the optical fiber changes its refractive index upon contact with the housing, especially at a cylindrical surface of the optical fiber, and would impair the light transmission.

[0019] A side of the housing refers to any arbitrarily shaped section of the housing, such as a surface of the housing, located at any point. For example, in a cylindrical housing, the sides encompass both the end faces and the lateral surfaces. In this case, the spring-loaded bearing can therefore be located in the axial and / or radial direction of the cylindrical housing. Alternatives, such as a rectangular housing shape, are also conceivable.

[0020] Preferably, the optical fiber is at least partially mirrored. For example, if the optical fiber is cylindrical, its cylindrical surface is mirrored. This reduces the effects of contact between the optical fiber and the housing.

[0021] The light guide rod is preferably rigid and has a diameter of at least 5 mm. Preferably, the diameter of the light guide rod is at most 25 mm. Preferably, the light guide rod is cylindrical, with the light guide rod having top and bottom surfaces facing the light entry and exit openings, respectively.

[0022] The light guide rod ensures decoupling, in particular thermal decoupling, between the side of the light entry aperture and the light exit aperture.

[0023] Preferably, the side of the housing with the light inlet opening is arranged in a protected area to be monitored, which is also referred to as a room and / or monitoring area, with ambient temperatures above 80°C, particularly preferably above 125°C.

[0024] The length of the light guide rod is preferably between 75 mm and 1500 mm, the length being particularly preferably selected based on the required or desired temperature difference between the monitoring area adjacent to the light inlet aperture and an operating area of ​​a sensor arranged at the light outlet aperture. This ensures the safe operation of a spark or flame detector, and in particular guarantees compliance with the operating temperature range below the specified limit value for the sensor and / or the electronics of the spark and / or flame detector.

[0025] The use of a light guide rod instead of a simple optical fiber, for example an arrangement of optical fibers such as a fiber bundle, allows a sensor, which can be arranged in the area of ​​the light exit aperture, to have the widest possible field of view on the side of the light entry aperture. For this purpose, preferably the entire sensor surface can be arranged on a top surface of the optical fiber.

[0026] According to the invention, a resilient bearing is provided as a bearing in the axial direction of the light guide rod on the side opposite the light entrance aperture. Due to its length, the axial extension is particularly significant and is accommodated by the resilient bearing.

[0027] Preferably, the light guide arrangement also includes protective optics arranged in front of the light guide rod at the light entry aperture.

[0028] The surface of the protective optics facing the area to be monitored forms the plane of entry of the electromagnetic radiation and forms the detection point of the electromagnetic radiation characteristic of sparks and / or flames.

[0029] The protective optics prevent particles or other objects located in the space facing the light entrance aperture from damaging the light guide rod. Preferably, the housing has a thread in the area of ​​the light entrance aperture, and the protective optics are designed to be screwed onto the housing.

[0030] This improves the durability of the light guide assembly, as the protective optics, for example in case of contamination, can be serviced using simple means without having to replace the entire light guide assembly. Furthermore, the thread preferably allows the contact pressure on the spring bearing to be adjusted.

[0031] Preferably, the housing has a fixing element for the protective optics in the area of ​​the light entrance aperture. The fixing element is particularly designed as a crimp, although other suitable fixing elements are also conceivable.

[0032] Additionally, the light guide arrangement has an elastic mounting in the radial direction around the light guide rod.

[0033] The crimp or other suitable fixing element of the housing for the protective optics preferably provides a fixed stop in the axial direction, which is used to define the spatial position of the bearing. According to the invention, more than one bearing is provided. The fixing element and / or bearing in the radial direction allow the light guide rod to be resiliently mounted in the axial and / or radial direction.

[0034] Preferably, the protective optics have or consist of a window element. The window element has two sides: one side facing the light guide rod or the interior of the housing, and an opposite side facing the protected area to be monitored. The window element is particularly preferably transparent to electromagnetic radiation at least in the wavelength range of 0.2 micrometers to 6 micrometers.

[0035] Preferably, a tolerance ring is freely mounted between the protective optics and the housing or light guide rod.

[0036] Preferably, the housing has cooling elements, in particular cooling fins, on its outer side in the axial direction.

[0037] The cooling elements arranged on the outside improve heat dissipation from the housing, thus enabling the length of the light guide arrangement, especially the light guide rod, to be as short as possible.

[0038] Preferably the light guide rod is made of or consists of sapphire and / or the housing is made of or consists of stainless steel.

[0039] Sapphire offers exceptionally good light-guiding properties across a broad wavelength range, making its use in light-guiding systems particularly advantageous. Stainless steel, on the other hand, exhibits good temperature resistance, enabling its use in demanding, especially very hot, environments. Of course, other suitable materials can also be used in other applications.

[0040] Preferably, a receptacle for receiving at least part of a sensor head is formed in the area of ​​the light exit aperture. The sensor head can thus be coupled to the light guide rod and thereby direct the light, for example, to a sensor. Particularly preferably, the sensor head to be received in the receptacle has at least one sensor on an end face that is arranged on the light guide rod in the position shown in the receptacle.

[0041] The coupling between the sensor head and the sensor housing is particularly preferred as it is reversible, allowing the light guide assembly or the sensor head to be replaced if necessary. The combination of sensor head and light guide assembly can therefore form a spark and / or flame detector.

[0042] Alternatively or additionally, one or more sensors, for example for detecting electromagnetic radiation that has been guided through the light guide rod, can be mounted directly on the light guide rod on the side of the light exit aperture.

[0043] Preferably, the light guide arrangement is designed to couple optical radiation and electronics or sensors.

[0044] The optical radiation is therefore detected by the sensors and must be coupled via the optical fiber. Preferably, however, negative environmental influences such as temperature and electromagnetic interference are decoupled.

[0045] Decoupling preferably refers to the spatial and thermal separation of the location where the characteristic radiation originates from the location where the generated radiation is detected. In particular, decoupling is not complete decoupling, but rather a sufficient reduction of mutual interference so that the function of the radiation-detecting sensors is not impaired by the environment of the monitored area.

[0046] Preferably, the light guide arrangement is designed for use in areas with demanding environmental influences, in particular with at least one of high temperatures, high voltages, strong electromagnetic interference radiation as well as radioactivity, aggressive atmospheres such as acids and bases, confined spaces and explosive atmospheres.

[0047] In areas with demanding environmental conditions, it is particularly advantageous that the light guide arrangement allows the generated radiation to be decoupled from its detection. This separation or decoupling protects the sensor from environmental influences and enables reliable operation without requiring a complex sensor design.

[0048] Preferably, the light guide arrangement is designed to guide light in the wavelength range of 0.2 to 6 micrometers, in particular of about 2.4 micrometers, and preferably for the detection of sparks and / or flames.

[0049] The area of ​​spark and / or flame detection is sensitive, as spark detection in particular allows an emerging fire to be identified so early that the effects can be minimized.

[0050] According to the invention, a spark and / or flame detector, in particular for use with fire alarm and / or extinguishing control centers, is further proposed with a light guide arrangement and a sensor head according to the invention, wherein the sensor head is configured to be coupled with the light output opening of the light guide arrangement.

[0051] Preferably, the sensor head is designed to be received in the receptacle of the housing of the light guide arrangement; alternatively, a suitable receptacle for receiving the light guide arrangement can also be provided on the side of the sensor head.

[0052] Depending on the application, the sensor head preferably incorporates different sensor technology, which, in the assembled state where the sensor head is coupled to the mount and thus to the light guide arrangement, is arranged on the light guide rod in such a way that the transmission of electromagnetic radiation is possible. Direct contact is just as possible as an intermediate distance, as long as the coupling of the electromagnetic radiation from the light exit aperture to the sensor technology is ensured.

[0053] Preferably, the sensor head is therefore designed to detect radiation emanating from the light exit aperture, which is characteristic of sparks or flames.

[0054] The spark and / or flame detector according to the invention can preferably be combined with any of the embodiments described as preferred with regard to the light guide arrangement.

[0055] According to the invention, a fire protection system is further proposed, comprising a spark and / or flame detector according to the invention and an evaluation unit. The evaluation unit is particularly preferably implemented as part of a fire alarm and / or extinguishing control center.

[0056] Alternatively, dedicated evaluation units and / or those integrated into the spark and / or flame detector are also conceivable. In these cases, the evaluation units are preferably configured to evaluate the sensor signals and forward them to a higher-level unit, for example, a control unit of a central system.

[0057] A connecting cable is preferably provided for linking the spark and / or flame detector to the evaluation unit. Alternatively, the connection and signal transmission can also be wireless.

[0058] In an advantageous embodiment of the fire protection system, it further comprises an extinguishing agent dispensing unit and / or a protective device, wherein this extinguishing agent dispensing device is controlled by the evaluation unit and / or a central control unit.

[0059] The protective device can be any device that is activated upon detection of sparks or flames in order to limit the damage. Examples of protective devices include material discharge flaps or power cut-off devices.

[0060] In a preferred embodiment, the fire protection system is designed as a spark extinguishing system and the evaluation unit and / or a central control unit is designed as part of a spark detector control center.

[0061] In another aspect, a method for the thermal decoupling of at least one sensor of a spark and / or flame detector from the detection point of the electromagnetic radiation characteristic of sparks or flames is proposed.The method comprises the steps: a) providing a light guide arrangement for transmitting electromagnetic radiation, in particular ultraviolet and / or infrared radiation, wherein the light guide arrangement has a housing and a light guide rod, the housing having a light inlet aperture and an opposite light outlet aperture, the light guide rod being arranged in the housing between the light inlet aperture and the light outlet aperture, b) guiding electromagnetic radiation by means of the light guide rod from the light inlet aperture to the light outlet aperture, c) detecting the electromagnetic radiation by the at least one sensor after the electromagnetic radiation has exited the light outlet aperture.

[0062] The method according to the invention can be combined analogously with all preferred embodiments, in particular of the described light guide arrangement.

[0063] According to the invention, an air gap is formed between the light guide rod and the housing, in particular in the axial direction of the light guide rod, wherein the air gap is preferably between 0.2 mm and 5 mm, wherein the method comprises the following step: d) Influencing, in particular by means of an air inlet device, the air in the air gap.

[0064] By influencing the air in the air gap, the temperature difference between the light inlet opening and the light outlet opening can be increased, in particular by removing heat.

[0065] Further advantages and special features are described below with reference to the attached figures. These show: Fig. 1 schematic and exemplary cross-section of a light guide arrangement; Fig. 2 Schematic and exemplary top view of a sensor head for radio frequency detection, Fig. 3Schematic and exemplary top view of a sensor head for flame detection, Fig. 4 Schematic and exemplary representation of a spark or flame detector in several views, Fig. 5 schematic and exemplary design of a housing for the light guide arrangement, Fig. 6 A schematic and exemplary fire protection system and Fig. 7 A schematic and exemplary flowchart of a process.

[0066] Figure 1 Figure 1 schematically and exemplarily shows a cross-sectional view of a light guide arrangement 1. The light guide arrangement 1 is designed to guide light, in particular ultraviolet, infrared and / or thermal radiation, from a light inlet aperture 12 to a light outlet aperture 14.

[0067] The light guide assembly 1 comprises a housing 10 in which a light guide rod 20 is spring-mounted. For mounting the light guide rod 20, the light guide assembly 1 includes a spring element 32, a spring element 34, and a spring element 36. It should be noted that the spring elements 32, 34, and 36 shown as examples can also be designed differently.

[0068] The spring elements 32, 34, and 36 allow the light guide rod 20 to expand relative to the housing 10 without causing stress. Furthermore, the typically highly sensitive light guide of the light guide rod 20 is protected by the mounting. It is known that different materials, in this case, for example, the light guide rod 20 and the housing 10, expand to different degrees when heated, which can lead to stress. This effect can be compensated for by the spring mounting.

[0069] An air gap of 0.2 mm to 5 mm is preferably provided between the light guide rod 20 and the housing 10. Air, in particular compressed air, can be introduced into the air gap by means of an air inlet device (not shown). The compressed air improves the cooling of the light guide rod 20 or the light guide assembly 1.

[0070] The spring element 32 is arranged in the area of ​​the light entry aperture 12 and is held in position, for example, by means of a tolerance ring 38. The tolerance ring 38, in turn, is fastened via a fixing device, for example, a thread 16, with which a protective optic 40 is fixed. The protective optic 40 has a window element 42, which is optically transparent for corresponding wavelengths and is designed, for example, as a lens or disc.

[0071] The protective optic 40 is therefore reversibly mountable, in particular unscrewable, and can thus be easily replaced in case of contamination or damage. In this example, the window element 42 is held in place by a flange 44 of the protective optic 40.

[0072] The spring element 34 is received in a groove, thus enabling a resilient mounting of the light guide rod 20 in the radial direction. The groove defines the position of the spring element 34 in the axial direction along the light guide rod 20. Finally, the spring element 36 is arranged on the side of the light exit aperture 14 and resiliently mounts the light guide rod 20 in the axial direction.

[0073] On the side of the light exit aperture 14 there is a receptacle 15 for receiving a sensor head, in particular for the reversible receiving of a sensor head, for example a flame and / or spark detector, as will be described later with reference to the Figures 2 to 4described in detail. In conjunction with a sensor head, the light guide arrangement 1 forms a spark and / or flame detector.

[0074] Preferably, one or more cooling elements 18 are arranged on the outside of the housing 10. The cooling elements 18 improve heat dissipation from the housing 10.

[0075] The light guide arrangement 1 according to the invention enables the detection of infrared radiation in an application range up to, for example, 450 °C, wherein cooling to a maximum operating temperature of a sensor head included in the holder 15 is achieved via the course of the light guide arrangement 1 in the axial direction.

[0076] In the example where the sensor is a silicon element that can withstand a maximum temperature of 100 °C, a cooling from 450 °C by ΔT of 350 K takes place. The length of the light guide rod 20 is determined by the required cooling, which means that shorter light guide rods 20 are possible for smaller achievable temperature differences.

[0077] The thermal conductivity of the light guide rod 20 and the surrounding housing 10 also influences the minimum length. The lower the thermal conductivity, the shorter the light guide rod 20 can be. The cooling of the light guide rod 20 is also determined by the housing 10, in particular by cooling elements 18 arranged on its surface, as well as by the ambient conditions such as still air, moving air, and the temperature in this environment.

[0078] The following table provides some examples of suitable materials for fiber optics as light guide rods 20, housings 10, or sensors, as well as their areas of application. Of course, other materials suitable for fiber optics, housings, and sensors are also possible: material use Thermal conductivity (W / (m*K)) Expansion coefficient Wavelength range (transmission >50%) (nm) Operating temperature range (°C) sapphire optical fibers 40 @ 25°C 5,6*10 -6< / K 300...5500 >1000 12 @ 400°C Borosilicate glass optical fibers 1,2 3,3*10 -6< / K 350...2500 500 Quartz glass optical fibers 1,38 0,54*10 -6< / K 170...3500 1000 stainless steel Housing 16 16*10 -6< / K - 450...850 titanium Housing 22 8,6*10 -6< / K - 550 aluminum Housing 220 23,8*10 -6< / K - 250 Brass Housing 123 21*10 -6< / K - 250 Silicon element detector - - 220...1100 -40...100 PbS detector - - 1000...3000 -40...65 PbSe detector - - 1000...4700 -40... 85 InGaAs detector - - 900... 1700 -40... 85 Pyrodetector detector - - 200...25000 -40... 85 UV sensor detector - - 180...280 -40...125

[0079] Materials with low thermal conductivity are better suited for thermal decoupling. For example, sapphire as the material for the light guide rod 20 is only suitable for a temperature difference ΔT of approximately 200 K with a length of 10 cm and a diameter of 20 mm. This assumes a stainless steel casing as the housing 10 and still air. For high-temperature applications up to a temperature difference ΔT of 350 K, borosilicate glass or quartz glass is preferably used.

[0080] For decoupling broadband wavelengths, for example in flame detection with pyrode detectors, sapphire is preferably used as the material of the light guide rod 20.

[0081] Cooling can be improved by selectively introducing air, for example by supplying compressed air, into the air gap between the light guide rod 20 and the housing 10. Preferably, cold air is introduced near the receptacle 15, i.e., near the detector, and discharged at the hot area, i.e., in the area of ​​the light inlet aperture 12.

[0082] As already mentioned, the light guide rod 20 is mounted on a vibration-damping bearing, since contact with the housing 10 on a cylindrical surface of the light guide rod 20 (which is, for example, cylindrical) would change its refractive index and thus impair the light transmission. Alternatively, the cylindrical surface could be mirrored, but this would require a more complex implementation. The vibration-damping bearing is also necessary to protect the fragile light guide rod 20.

[0083] In a specific embodiment, the light guide rod 20 is between 75 mm and 1500 mm long and has a diameter of 5 mm to 25 mm. The larger diameters, particularly from 10 mm to 25 mm, specifically include the case where optical monitoring is provided, cf. Figs. 2 and 3 .

[0084] It is known that, for example, in pneumatic conveyors for materials such as flour or shavings, foreign particles such as stones can lead to the generation of sparks.

[0085] The present invention provides the light guide arrangement 1, which can be used in a spark detector and / or flame detector.

[0086] Compared to quartz, sapphire as the material for the light guide rod 20 has a higher transmission, but requires better protection against vibrations. The tolerance rings 38 can, for example, be formed with an accordion-like shape for this purpose. Due to the high temperatures involved, spring elements or tolerance rings made of rubber materials are not usually possible.

[0087] In contrast to known light guide arrangements, the area for sensors available in the region of the light exit aperture 14 is particularly large enough to accommodate the sensor(s) completely.

[0088] At the in Fig. 1 In the light guide arrangement 1 shown, the spring-loaded bearing absorbs the different expansions and shocks.

[0089] Fig. 2 schematically and exemplarily shows a top view of a sensor head 100, which is used for recording in the Fig. 1The surface shown is formed in the recess 15. It is designed to be positioned at the light emission aperture 14, i.e., in contact with or near it. An insertion area 115 is provided for placement within the recess 15.

[0090] The figure shows a first sensor 50 and a second sensor 60, which are coupled to the light guide rod 20 in their mounting position. The first sensor 50 can, for example, be an optical monitoring sensor designed to monitor whether visibility through the light guide rod 20 is ensured.

[0091] The second sensor 60 can be the sensor that ultimately detects the spark and / or flame. It should be noted that the diameter of the light guide rod 20 can be smaller if the first sensor 50 is omitted. The arrangement of both the first sensor 50 and the second sensor 60 improves the reliability of a spark and / or flame detector 2, which is fully integrated into Fig. 4 shown.

[0092] The sensor head 100 also includes electronics 120, which are not shown further. In the simplest case, the electronics 120 are not electronics in the true sense, but are merely configured to transmit signals from the sensors 50, 60 to evaluation electronics, for example a fire alarm and / or extinguishing control panel, cf. Fig. 6 , forwarding. Alternatively, the data or signal processing can also be carried out partially or completely in the sensor head 100.

[0093] During the execution of the Fig. 2 For example, it is a sensor head 100 of a spark detector, since the second sensor 60 is designed as a single sensor for detecting a specific wavelength characteristic of sparks.

[0094] Fig. 3 Figure 1 schematically and exemplarily shows a top view of another sensor head 100. In this example, the second sensor 60 has three narrowband sensor elements 62, which preferably detect three different wavelengths of optical radiation. This embodiment is preferably designed for a flame detector.

[0095] The sensor head 100 has a housing 110 which includes means for mounting the sensor head 100 in the receptacle 15. For example, the connection can be made by a form fit, in the form of a bayonet fitting, cf. Fig. 5 , or other connection types.

[0096] It should be noted that the sensor head 100 is preferably screwed into the receptacle 15. This makes it possible to configure the light guide arrangement 1 according to the invention as a spark detector, a flame detector, or, in a further embodiment, as a combined spark and flame detector. For this purpose, for example, a thread can be provided in the receptacle 15 and the housing 110 can have a corresponding thread. Other methods of fixing are, of course, also conceivable.

[0097] Fig. 4Figure 1 schematically and exemplarily shows various views of a spark and / or flame detector 2, which includes a light guide assembly 1 and a sensor head 100 shown in the photograph 15. A flexible connecting cable 70 enables the transmission of data from the sensor head 100 to an evaluation unit, in particular a fire alarm and / or extinguishing control panel. Cooling fins 18 are shown attached to the housing 10. The housing 10 is rigid to stabilize the light guide rod 20.

[0098] Fig. 5 schematically and exemplarily shows a part of the housing 10 of a light guide arrangement 1, namely the part of the receiver 15. In the particular design of the Fig. 5 The mount has 15 guide rails 19 for attaching a sensor head 100, which has corresponding coupling means. Of course, other types of fixation are also possible.

[0099] As an alternative to the design of the receptacle 15 as a socket, the receptacle 15 can also be designed as a plug, with the corresponding receptacle on the side of the sensor head 100. Accordingly, the sensor head 100 can also have suitable coupling means, for example, cam guides.

[0100] Fig. 6Figure 1 schematically and exemplarily shows a fire protection system 5 according to the invention. In this example, the fire protection system 5 has an evaluation unit 4 designed as a fire alarm and / or extinguishing control center, which is connected to several spark and / or flame detectors 2 via connecting lines 70. The evaluation unit 4 is, in particular, the central control unit of the fire protection system 5. As a further example, a separate evaluation unit 4' is shown, which is arranged between the spark and / or flame detector 2 and the fire alarm and / or extinguishing control center and evaluates and forwards the detection signals of the spark and / or flame detector 2.

[0101] In a monitoring area 6, which is, for example, the interior of a material dryer, the light entry aperture of, in this example, two spark and / or flame detectors 2 is located. Furthermore, a fire extinguishing agent dispensing device and / or a protective device 9, for example, a fire extinguishing nozzle or other device, is shown. When configured as a fire extinguishing agent dispensing device, it is designed to dispense fire extinguishing agent into the monitoring area 6 when appropriately controlled. Examples of protective devices are material discharge flaps or power cut-off devices. A fire extinguishing agent dispensing device can be configured in any way known to a person skilled in the art and may, for example, include a fire extinguishing agent reservoir, a triggering device, a piping system, and / or a fire extinguishing nozzle.

[0102] Fig. 7schematically and exemplarily shows a flowchart of a method 200 for the thermal decoupling of at least one sensor 50, 60 of a spark and / or flame detector 2 from the detection point of the electromagnetic radiation characteristic of sparks or flames.

[0103] In step 210, a light guide arrangement 1 for transmitting electromagnetic radiation, in particular ultraviolet and / or infrared radiation, is provided. The light guide arrangement 1 comprises a housing 10 and a light guide rod 20. The housing 10 has a light inlet opening 12 and an opposing light outlet opening 14. The light guide rod 20 is arranged in the housing 10 between the light inlet opening 12 and the light outlet opening 14.

[0104] In step 220, electromagnetic radiation is guided from the light inlet opening 12 to the light outlet opening 14 by means of the light guide rod 20.

[0105] In step 230, the electromagnetic radiation is detected by at least one sensor 50, 60 after the electromagnetic radiation exits the light exit aperture 14.

[0106] Finally, in an optional step 240, the air in an air gap between light guide rod 20 and housing 10 is influenced, in particular by means of an air inlet device not shown. List of reference symbols

[0107] 1. Light guide arrangement 2. Spark and / or flame detector 4. Central control unit 4. Evaluation unit 5. Fire protection system 6. Monitoring area 9. Extinguishing agent dispensing device and / or protective device 10 Housing 12 Light inlet aperture 14 Light outlet aperture 15 Mounting 16 Thread 18 Cooling elements 19 Guide rails 20 Light guide rod 32Spring element 34Spring element 36Spring element 38Tolerance ring 40 Protective optics 42 Window element 44 Fixing element 50 First sensor 60 Second sensor 62 Sensor element 70 Connection cable 100 Sensor head 110 Housing 115 Insertion area 120 Electronics 200 Procedure 210 Step of Provisioning 220 Step of Guiding 230 Step of Detecting 240 Step of Influencing

Claims

1. A light guiding arrangement (1) for transmitting electromagnetic radiation, in particular ultraviolet and / or infrared radiation, wherein the light guiding arrangement (1) comprises a housing (10) and a light guiding rod (20), wherein the housing (10) comprises a light entrance opening (12) and a light exit opening (14) located opposite the light entrance opening (12), wherein the light guiding rod (20) is arranged in the housing (10) between the light entrance opening (12) and the light exit opening (14), wherein the light guiding rod (20) is elastically mounted on at least one side in the housing (10) to compensate for different thermal expansions between the light guiding rod (20) and the housing as well as impacts on the light guiding rod, wherein the light guiding arrangement (1) comprises a first, second, and third spring element (32, 34, 36), wherein the first spring element (32) is arranged in the region of the light entrance opening (12), wherein the second spring element (34) is received in a groove to enable an elastic mounting of the light guiding rod (20) in the radial direction, and wherein the third spring element (36) is arranged on the side of the light exit opening (14) and elastically mounts the light guiding rod (20) in the axial direction, wherein the light guiding arrangement (1) comprises an air gap, in particular an air gap that radially surrounds the light guiding rod (20), between the light guiding rod (20) and the housing (10), and wherein the light guiding arrangement (1) further comprises an air inlet device that is configured to introduce air, in particular compressed air, into the air gap between the light guiding rod (20) and the housing (10).

2. The light guiding arrangement (1) according to claim 1, wherein the elastic mounting is formed as a mounting in the axial direction of the light guiding rod (20) on the side opposite the light entrance opening (12).

3. The light guiding arrangement (1) according to any one of the preceding claims, wherein the air gap is between 0.2 mm and 5 mm.

4. The light guiding arrangement (1) according to any one of the preceding claims, further comprising a protective optic (40) arranged in front of the light guiding rod (20) at the light entrance opening (12), wherein the housing (10) preferably comprises a thread (16) in the region of the light entrance opening (12), and wherein the protective optic (40) is configured to be screwed onto the housing (10).

5. The light guiding arrangement (1) according to any one of the preceding claims, wherein a fixing element for a protective optic (40), in particular a flange (44), is formed in the region of the light entrance opening (12), and / or the light guiding arrangement (1) comprises an elastic mounting in the radial direction around the light guiding rod (20).

6. The light guiding arrangement (1) according to a combination of claims 4 and 5, wherein a tolerance ring (38) is freely mounted between the protective optic (40) and the housing (10) and / or the light guiding rod (20).

7. The light guiding arrangement (1) according to any one of the preceding claims, wherein the housing (10) comprises cooling elements, in particular cooling fins, on its outside in the axial direction.

8. The light guiding arrangement (1) according to any one of the preceding claims, wherein the light guiding rod (20) comprises or consists of sapphire and / or the housing (10) comprises or consists of stainless steel.

9. The light guiding arrangement (1) according to any one of the preceding claims, wherein a receptacle (15) for receiving a sensor head (100), in particular a sensor head (100) of a flame and / or spark detector (4), is formed in the region of the light exit opening (14).

10. The light guiding arrangement (1) according to any one of the preceding claims, wherein the light guiding arrangement (1) is configured for coupling optical radiation and electronics or sensors and is preferably designed for use in environments with high temperatures up to 450°C.

11. The light guiding arrangement (1) according to any one of the preceding claims, wherein the light guiding arrangement (1) is configured for guiding light in the wavelength range of 0.2 to 6 µm, in particular of approximately 2.4 µm, and preferably for the detection of sparks and / or flames.

12. A spark and / or flame detector (2), in particular for use with fire alarm and / or extinguishing control centers, comprising a light guiding arrangement (1) according to any one of the preceding claims and a sensor head (100), wherein the sensor head (100) is configured to be coupled to the light exit opening of the light guiding arrangement (1).

13. A fire protection system (5) for detecting sparks and / or flames, comprising a spark or flame detector (2) according to claim 12, an evaluation unit (4, 4'), in particular a fire alarm and / or extinguishing control center, and optionally a extinguishing agent dispensing unit and / or a protective device (9), wherein said extinguishing agent dispensing unit is controlled by the evaluation unit (4') and / or a central control unit (4).

14. A method (200) for thermal decoupling of at least one sensor of a spark and / or flame detector from detection location of electromagnetic radiation characteristic of spark or flame, comprising the steps of: providing (210) a light guiding arrangement (1) for transmitting electromagnetic radiation, in particular ultraviolet and / or infrared radiation, wherein the light guiding arrangement (1) comprises a housing (10) and a light guiding rod (20), wherein the housing (10) comprises a light entrance opening (12) and a light exit opening (14) located opposite the light entrance opening (12), wherein the light guiding rod (20) is arranged in the housing (10) between the light entrance opening (12) and the light exit opening (14), wherein the light guiding arrangement (1) comprises an air gap, in particular an air gap that radially surrounds the light guiding rod (20), between the light guiding rod (20) and the housing (10), and wherein the light guiding arrangement (1) further comprises an air inlet device that is configured to introduce air, in particular compressed air, into the air gap between the light guiding rod (20) and the housing (10), wherein the light guiding arrangement (1) comprises a first, second, and third spring element (32, 34, 36), wherein the first spring element (32) is arranged in the region of the light entrance opening (12), wherein the second spring element (34) is received in a groove to enable an elastic mounting of the light guiding rod (20) in the radial direction, and wherein the third spring element (36) is arranged on the side of the light exit opening (14) and elastically mounts the light guiding rod (20) in the axial direction, guiding (220) electromagnetic radiation by means of the light guiding rod (20) from the light entrance opening (12) to the light exit opening (14), detecting (230) the electromagnetic radiation by the at least one sensor (50, 60) after the electromagnetic radiation has exited the light exit opening (14).

15. The method (200) according to claim 14, wherein an air gap is formed between the light guiding rod (20) and the housing (10), in particular in the axial direction of the light guiding rod (20), wherein the air gap preferably has a width between 0.2 mm and 5 mm, wherein the method comprises the following step: influencing (240) the air in the air gap, in particular by means of an air inlet device.