Linear detection means, in particular measuring strip, for detecting loads along a section, device and system

Abstract

The invention relates to a linear detection means, in particular a measuring strip (1), for detecting loads along a section, in particular track section, comprising a number N of optical fibres (2), where N > 1, wherein the detection means has at least one measuring portion (4) which extends over at least part of the detection means, wherein at least one of the optical fibres (2) is designed as a measuring fibre which has, in the measuring portion (4), a plurality of sensors arranged at certain points, wherein the maximum dimension of the detection means in a cross-sectional plane is at most 20 cm. The invention also relates to a device and a system having such a detection means.

Description

[0001] Linear detection means, in particular measuring tape, for detecting loads along a route, device and system

[0002] This patent application claims priority from European patent application EP 23 186 284.8, the contents of which are incorporated herein by reference.

[0003] The invention relates to a linear detection means, in particular a measuring tape, for detecting loads along a path, as well as a device and a system with such a measuring tape.

[0004] Devices for detecting loads along a track, in particular along a railway track, a pipeline, a cable, an engineering structure such as a bridge, and / or a safety device, are known from the prior art. In particular, it is known to lay optical fibers along a railway line and equip the optical fibers with strain sensors, in particular Fiber Bragg Grating (FBG) sensors. Such FBG sensors allow the highly precise and highly dynamic measurement of deformations in the optical fiber connected to the track, such as those inevitably occurring when a train passes by.

[0005] However, one problem with laying optical fibers with FBG sensors is that only a limited number of FBG sensors can be arranged and interrogated in one optical fiber, usually around 100 to a maximum of 2000. For a given resolution of, for example, 2 m, this severely limits the length of the measuring optical fiber. For this reason, in existing applications, FBG sensors are only provided at dedicated points along the route, for example, to detect loads on vulnerable areas or to monitor dedicated route sections, as described, for example, in the publication WO 2016 / 150670 A1. However, high-frequency and high-precision position measurement of moving vehicles along a route at arbitrarily short spatial intervals is not possible with these devices.

[0006] It is an object of the invention to provide an improved detection means, in particular a measuring tape, for detecting loads along a track. In particular, the detection means is intended to solve the aforementioned problem and to create a detection means that is cost-effective to manufacture and simple to use and allows the position of moving vehicles to be measured at arbitrarily short spatial intervals along the entire track, preferably continuously, with high resolution and high dynamics. The position measurement should preferably function independently of the vehicle speed in a range from 0 to 350 km / h and the device should withstand the environmental conditions of railway operations, for example, and be low-maintenance. Installation should be possible in an automated manner both on existing tracks and on new systems.

[0007] These and other objects of the invention are achieved with a linear detection means, in particular a measuring tape, according to claim 1.

[0008] A linear detection means according to the invention, in particular a measuring tape, is designed to detect loads, in particular mechanical loads, along a route, in particular a track section, and comprises a number N of optical fibers, preferably running substantially parallel to one another, where N > 1. The detection means comprises at least one measuring section that extends over at least part of the detection means. At least one of the optical fibers is preferably designed as a measuring fiber that has a plurality of sensors arranged at specific points in the measuring section and optionally has no sensors outside this measuring section. The sensors are preferably designed as strain sensors, particularly preferably as Fiber Bragg Grating (FBG) sensors.

[0009] The linear detection means can be designed as a cable-shaped detection means. In cross-section, the linear detection means can be round, in particular circular or oval, and / or polygonal, in particular rectangular, in particular square or non-square.

[0010] The ratio between the longitudinal extent and a maximum transverse extent, in particular in a cross-sectional plane, of the linear detection means is preferably at least 100: 1, in particular at least 1,000: 1, in particular at least 10,000: 1, and / or a maximum of 500,000: 1. Preferably, the linear detection means is designed to be flexible in shape, in particular bendable, in particular in the manner of a bendable cable.

[0011] The maximum dimension, in particular a width, of the linear detection means in a cross-sectional plane, in particular perpendicular to the longitudinal extent, is preferably a maximum of 30 cm, in particular a maximum of 20 cm, in particular a maximum of 15 cm, in particular a maximum of 10 cm, in particular a maximum of 5 cm, in particular a maximum of 3 cm, in particular a maximum of 2 cm, in particular a maximum of 1 cm, and / or at least 0.1 mm, in particular at least 1 mm, in particular at least 1 cm, in particular at least 2 cm, in particular at least 3 cm.

[0012] A thickness of the linear detection means is preferably a maximum of 3 cm, in particular a maximum of 1 cm, in particular a maximum of 0.5 cm, and / or at least 0.1 mm, in particular at least 0.5 mm, in particular at least 1 mm.

[0013] A cross-sectional area of ​​the linear detection means is preferably in a range of 10 mm 2 up to 20 cm 2 , especially 20 mm 2up to 10 cm 2 , especially 50 mm 2 up to 5 cm 2 .

[0014] The linear detection means is preferably designed in the form of a measuring tape. The tape shape means that the detection means has a cross-sectional aspect ratio of at least 1.2:1, in particular at least 1.5:1, in particular at least 2:1, in particular at least 5:1, in particular at least 10:1. The measuring tape is preferably substantially rectangular in cross-section, in particular with rounded or sharp edges.

[0015] Preferably, the linear detection means can be designed to be flexible enough to allow it to be wound non-destructively onto a spool and / or reel. In particular, the invention relates to a spool and / or reel with a linear detection means wound thereon. This advantageously ensures that the detection means is particularly space-saving and can be transported safely, in particular to the structure, in particular the track. Preferably, at least one, and in particular several, of the sensors are designed as strain sensors, in particular as fiber Bragg grating (FBG) sensors. Such sensors are particularly robust in operation and precise. Furthermore, such sensors are particularly robust against interference, in particular electromagnetic interference, and are therefore particularly suitable for use on electrified track sections.Preferably, the linear detection means comprises at least 10, in particular at least 20, in particular at least 50, in particular at least 250, in particular at least 1,000, and / or a maximum of 10,000, in particular a maximum of 1,000, in particular a maximum of 500, strain sensors, in particular fiber Bragg grating (FBG) sensors.

[0016] Preferably, a length of the linear detection means, in particular of the measuring section, can be at least 1 m, in particular at least 5 m, in particular at least 10 m, in particular at least 25 m, in particular at least 50 m, in particular at least 100 m, in particular at least 500 m, in particular at least 1 km, and / or a maximum of 10 km, in particular a maximum of 5 km, in particular a maximum of 2 km.

[0017] The detection means can have several measuring sections, which are preferably connected in series. Thus, the length of the detection means can be a multiple of the at least one measuring section. Alternatively, these can be connected in parallel, in particular to provide redundancy or reliability. For example, at least 2, in particular at least 2, in particular at least 4, in particular at least 16, of the measuring sections can be provided, which are preferably connected in series. Thus, the detection means can cover a large length of the structure, in particular the track, in particular the track rail.

[0018] Preferably, the at least one measuring fiber can comprise at least 10, in particular at least 20, in particular at least 50, in particular at least 100, in particular at least 1,000, and / or a maximum of 1,000, in particular a maximum of 500, sensors, in particular strain sensors. This allows a particularly high measurement resolution and / or a particularly long measurement length to be achieved.

[0019] According to a preferred aspect, the linear detection means can have at least one linear enveloping structure. In the cross-sectional plane of the detection means, at least one of the optical fibers and / or a signal transmission element, in particular an electrical line and / or an optical fiber, can be arranged within the enveloping structure and / or outside the enveloping structure. Preferably, at least one measuring fiber is arranged outside the enveloping structure, and at least one optical fiber, in particular a measuring fiber, and / or a signal transmission element, in particular an electrical line and / or an optical fiber, is arranged within the enveloping structure. The enveloping structure can be tubular. The enveloping structure can be round in cross section, in particular oval or circular, or polygonal, in particular rectangular.Preferably, the at least one optical fiber within the enveloping structure is not coupled to the enveloping structure, in particular in the longitudinal direction, in particular not mechanically, in particular not materially. The at least one optical fiber can be loosely inserted within the enveloping structure. Preferably, the at least one optical fiber is integrated into the enveloping structure in a longitudinally force-coupled manner, or in such a way that no forces, in particular no longitudinal forces, can be transmitted between the enveloping structure and the at least one optical fiber arranged therein. This makes the at least one optical fiber particularly resistant to interference and robust in operation.

[0020] The at least two optical fibers can run substantially parallel to each other, in particular can be arranged twist-free or twisted.

[0021] A distance between two adjacent sensors of the detection means, in particular of the at least one measuring section, in particular along the longitudinal direction of the detection means, can be in a range from 1 cm to 100 m, in particular from 10 cm to 50 m, in particular from 50 cm to 10 m. Preferably, at least 5, in particular at least 10, in particular at least 20, of the adjacent sensors, in particular consecutive sensors, of the same optical fiber are arranged equidistant from one another.

[0022] Preferably, at least one of the sensors, in particular at least two, in particular at least five, in particular at least ten, of the sensors can be designed as temperature sensors, in particular to detect mechanical or thermal loads on the track rails.

[0023] The detection means preferably comprises a substrate in which the plurality of optical fibers are embedded. The substrate preferably surrounds the plurality of optical fibers at least partially, in particular completely, in cross-section. The substrate can comprise, in particular consist of, a plastic, in particular a fiber-reinforced plastic, in particular a short-fiber-reinforced and / or a long-fiber-reinforced plastic, and / or an elastomer. The plastic preferably comprises an epoxy and / or a rubber and / or NBR. The sheath structure is preferably embedded in the substrate. Preferably, all optical fibers are enclosed by the substrate. The detection means is preferably provided in one piece. This makes the detection means particularly easy to handle and robust.

[0024] The linear detection means, in particular the substrate, can comprise a thermoplastic and / or a pre-prepared material and / or a coating, in particular an adhesion promoter, in particular a sizing agent. The adhesion promoter is preferably designed to improve a material-to-material bond, in particular an adhesive bond, in particular with the structure, in particular the track rail.

[0025] The invention further relates to a device with the linear detection means and at least one further device, for example an optoelectronic interrogation unit and / or a service box and / or a data processing unit, in particular a central one, and / or a control device and / or the spool and / or the reel. The advantages of the device preferably correspond to the advantages of the linear detection means. The device is preferably further developed with at least one of the features described in connection with the detection means.

[0026] The invention is further directed to a system comprising at least one extended structure, in particular a track, in particular a track rail, and at least one detection means, wherein the detection means is preferably connected to the structure, in particular the track, in particular the track rail, in a materially bonded and / or force-locked manner. The advantages of the system preferably correspond to the advantages of the detection means or the device. The system is preferably further developed with at least one of the features described in connection with the detection means or the device.

[0027] The structure is preferably an infrastructure structure, an engineering structure, a road, a pipeline, a bridge, a suspension cable, a supporting structure, a geotechnical facility, a supply channel, in particular for an above-ground and / or underground facility, a pipeline or long-distance fuel pipeline, in particular for gas and / or oil, a water pipeline, in particular a hot water pipeline, in particular a geothermal pipeline, an energy plant, in particular a wind turbine, in particular a wind turbine tower, a building, in particular with a height of at least 50 m, in particular at least 100 m, a high-speed transport system, in particular in which a transport capsule, in particular for persons, moves in a largely airless tube, a magnetic levitation train, a cable car and / or a railway track.The structure may also be a means of transport, for example a rail vehicle and / or a ship and / or an aircraft and / or a road vehicle, for example a car and / or a truck.

[0028] The system can be designed for, in particular continuous, structural integrity monitoring of at least one structure, in particular a plurality of structures. In particular, the detection means can be arranged, in particular fastened, to the track rail, in particular to a surface, in particular to an underside, of the track rail, in particular to a groove in the track rail and / or a groove in an intermediate layer. The detection means can be arranged, in particular fastened, between the track rail, in particular a rail foot, and at least one track sleeper. For example, an intermediate layer can be provided between the track rail and the track sleeper, to which intermediate layer the detection means is arranged, in particular fastened.

[0029] Preferably, the detection means is designed for fastening to a rail foot, in particular for clamping and / or gluing to the rail foot, in particular to an underside of the track rail.

[0030] The measuring section can extend substantially over the entire length of the detection means, wherein at least one, in particular a maximum of 20, in particular a maximum of 3, in particular only a single one, of the N optical fibers is designed as a measuring fiber with sensors. The detection means can have multiple optical fibers, of which only a small portion, in particular only a single one, is designed as a measuring fiber. By combining several such detection means, an extended area can be monitored. In particular, the detection means can be divided into two or more measuring sections, wherein the optical fibers of the measuring sections are led out of the measuring sections and connected in series, in particular spliced, in at least one service box.

[0031] An optical fiber designed as a measuring fiber can always be connected to an optical fiber not designed as a measuring fiber, so that exactly one optical fiber has the sensors in each measuring section. The detection means preferably has several consecutive, non-overlapping measuring sections, with strain sensors being provided in each measuring section and / or no strain sensors being provided outside of this measuring section. Even when monitoring long distances, the number of strain sensors per optical fiber can thus be kept moderate. By connecting one measuring section of one optical fiber directly to the measuring section of another optical fiber, a seamless transition between the measuring sections can be ensured when evaluating the signals.

[0032] It can be provided that all N optical fibers of the detection device are designed as measuring fibers, wherein the detection device preferably has N directly consecutive, non-overlapping measuring sections and / or wherein the optical fibers each have sensors in a measuring section and / or have no sensors outside of this measuring section. Such detection devices can be used to design modular systems for monitoring long distances that are particularly simple to install and maintain and can also be easily scaled.

[0033] According to the invention, the number of optical fibers N can be in the range from one to two hundred, in particular from one to fifty, preferably approximately five to thirty, in particular from ten to twenty. The measuring sections can each have a length of approximately 100 m to approximately 10,000 m, preferably approximately 1,000 m. The length of the entire detection means can be approximately 200 m to approximately 50 km, preferably approximately 10 km to approximately 20 km. Optionally, the detection means can have at least one electrically conductive connection in addition to the optical fibers. The number of electrically conductive connections can be fewer, equal to, or higher than the number of optical fibers and / or lie in the range described above for the optical fibers.

[0034] Preferably, at least some, in particular all, of the optical fibers in the detection device are redundant, in particular double, triple, or quadruple. This advantageously increases reliability. In particular, the function of a defective optical fiber can be taken over by another, intact optical fiber, thereby avoiding the considerable effort required to relocate or repair the detection device. Corresponding redundancy can be provided, in particular, with regard to the at least one sensor, in particular the optical fiber. Specifically, several of the sensors can be arranged at each measuring point.

[0035] According to the invention, at least approximately 100 to 10,000, preferably approximately 500 to 1,000 strain sensors, preferably FBG sensors, are arranged in each of the measuring sections, wherein the distance between the strain sensors is preferably at least approximately 1 cm to approximately 100 m, particularly preferably a maximum of approximately 200 cm, and / or wherein the strain sensors are preferably arranged equidistant from one another. This ensures sufficient spatial resolution for detecting rail vehicles.

[0036] According to the invention, at least one additional optical fiber running parallel to the other optical fibers can be provided, which has FBG temperature sensors evenly distributed along the entire length of the detection means, arranged at a distance of approximately 1 m to approximately 100 m, preferably approximately 50 m. This allows temperature measurements to be taken at longer intervals along the entire length. According to the invention, it can also be provided that additional optical fibers, for example, serving for communication or data transmission, are provided in the detection means.

[0037] According to the invention, it can be provided that the optical fibers are coated individually or together, for example with a glass fiber reinforced polymer.

[0038] Preferably, the optical fibers are embedded parallel to each other in a flat carrier tape, for example, made of glass-fiber-reinforced polymer (composite material). This ensures increased robustness of the detection device while simultaneously providing high elasticity for installation. For example, 10 or more optical fibers with strain sensors and one optical fiber with temperature sensors can be embedded in a common carrier tape.

[0039] According to the invention, it can be provided that directly consecutive measuring sections are provided in optical fibers arranged directly next to one another. In other words, it can be provided that measuring sections that directly follow one another along the path are arranged in optical fibers that are directly adjacent to one another or are embedded directly next to one another in the carrier tape.

[0040] According to the invention, the detection means, in particular the carrier tape, can have a width of approximately 2 mm to approximately 30 mm and / or a thickness of approximately 0.1 mm to approximately 20 mm. The length of the carrier tape can be approximately 200 m to approximately 50 km, preferably approximately 10 km.

[0041] The invention further relates to a device for monitoring extensive structures, for example civil engineering structures, roads, pipelines, supporting cables, supporting structures or railway tracks, comprising at least one detection means according to the invention.

[0042] According to the invention, it can be provided that the detection means is designed to be materially connected, in particular glued, to the structure, in particular to a supporting element of the structure.

[0043] According to the invention, it can be provided that two or more detection means are arranged in series or in parallel along the path, wherein one or more optoelectronic interrogation units are provided between the detection means, which are designed to interrogate all FBG sensors, for example strain sensors, of the optical fibers running in the detection means.

[0044] The optoelectronic interrogation unit can be provided as a single multi-channel interrogation unit or in the form of several single-channel interrogation units.

[0045] For example, the query can be performed at a sampling rate of over 1 Hz for static and quasi-static applications, such as in geotechnical engineering or civil engineering structures such as bridges. However, the query can also be performed at a sampling rate of up to 20 kHz for dynamic processes, such as vehicle germination on rails or the assessment of the running characteristics of rail vehicles by measuring the forces exerted by the vehicle wheels on the superstructure, especially the rail.

[0046] The device preferably has a control device which is designed to determine a position and / or the running characteristics of a vehicle, in particular a track vehicle, based on a signal from the detection means and / or to determine the condition of a route, in particular a track section, and / or to determine a temperature, in particular of the route, in particular of a track section, in particular of the track rail. Particularly preferably, the device, in particular the control device, is designed to assess both the running characteristics of a vehicle, in particular a track vehicle, and the condition of the route, in particular of the track section, based on the signal from the detection means. For this purpose, the control device can have a means for processing digital data, in particular a processor.

[0047] The optoelectronic interrogation unit can be designed, in particular, to interrogate approximately 20 parallel optical fibers, each with approximately 500 FBG sensors, for example, strain sensors. Thus, a single optoelectronic interrogation unit can be used to interrogate a section the length of several detection devices, for example, in intersections, forks, or switch areas.

[0048] According to the invention, it can be provided that several detection means are arranged adjacent to one another or in parallel, wherein a service box is provided between the detection means along the route, preferably at any distance of up to 20 km, to enable maintenance of the device. The service box can be used to connect an optoelectronic interrogation unit in the event of a fault or for maintenance of the device. For this purpose, the optical fibers can be provided with plug connections in the area of ​​the service box and / or led out. If a detection means is damaged or tears, a replacement strip with the same strain sensors can be glued parallel to the torn detection means and / or the optical fibers can be pulled out of the strips and spliced. Appropriate protective boxes can be provided to protect the splice connections.

[0049] The strain sensors can therefore also be used in the form of self-monitoring to detect and / or localize damage and errors in the sensing devices.

[0050] According to the invention, for monitoring railway tracks with two rails, in particular for locating trains or measuring the loads exerted by rail vehicles, one or more parallel detection devices, in particular for switches and / or crossing areas, are provided, which are designed to be arranged, in particular glued, on the two rails in a material-to-material manner. The measured values ​​of the two parallel detection devices can be queried independently of one another to ensure measurement redundancy.

[0051] According to the invention, further precautions can be taken to ensure the continuity and integrity of the measured values ​​in crossing areas, when a route is divided into different sections, or at junctions where rails are switched using switches. For example, optical switches can be provided at such locations which automatically connect the detection means of a first section of track with the detection means of a subsequent section of track. This enables seamless monitoring even if the sections of track are not integral. The optical switch can be designed to connect several detection means to one another and / or to control at least two of the detection means with a time offset, in particular to read out their signals with a time offset. This allows the signals from the detection means to be evaluated particularly efficiently.

[0052] Alternatively, it may also be provided that dedicated optoelectronic interrogation units are provided for the different route sections, which are connected to one another so that the measurement data of a subsequent route section can be automatically used by the interrogation unit of a first route section.

[0053] According to the invention, it can be provided that the detection means are arranged offset from one another in the longitudinal direction along the track. Particularly preferably, the detection means can be arranged offset from one another by half the distance between the strain sensors. Preferably, the detection means can be arranged offset from one another along the track by a distance of at least 1 cm to 20 m, for example 50 cm or 100 cm. In practice, this allows a doubling of the resolution when determining the position of a rail vehicle. According to the invention, it can be provided that an intermediate layer is provided between the structure and a subsurface, wherein the detection means is arranged in a groove in the intermediate layer. The detection means can thereby be protected from damage.

[0054] According to the invention, it can be provided that the structure is a track with two rails. In this case, it can be provided that an intermediate layer with a groove is arranged on the underside of one or both rails, wherein the groove of the intermediate layer is designed for the arrangement of the detection means. Since experience has shown that the outer side of a rail is subject to greater loads, the groove is preferably arranged on the inner side of the rail so that the detection means experiences less wear. In particular, in the case of a track with two rails, both rails can be provided with intermediate layers, wherein grooves for inserting the detection means are provided in the intermediate layers, and wherein these grooves are preferably each arranged on the inner side of the rails, i.e. the side facing the other rail.

[0055] The invention further relates to the use of the detection means according to the invention, in particular a device according to the invention, in particular on the structure, in particular the track, in particular the track rail, in particular for the continuous detection of the position and optionally for the assessment of the running characteristics of a vehicle along the route or for the assessment of the track condition.

[0056] Further features of the invention will become apparent from the patent claims, the drawings, and the following description of the figures. The invention will now be explained in more detail using exemplary embodiments. They show:

[0057] Fig. 1a - 1b are schematic views of an embodiment of a detection means according to the invention;

[0058] Fig. 2 is a schematic view of a detection means according to the invention with three measuring sections connected in series using a service box;

[0059] Fig. 3a - 3b are schematic views of a further embodiment of a detection means according to the invention;

[0060] Fig. 4 is a schematic view of an arrangement of two detection means according to the invention arranged in series along a path using an optoelectronic multi-channel interrogation unit;

[0061] Fig. 5a is a schematic view of an arrangement of two detection means according to the invention arranged parallel and offset from one another along a track with two rails;

[0062] Fig. 5b is a schematic sectional view of a track with two rails, on the underside of each of which a detection means according to the invention is arranged in a groove of an intermediate layer; Figs. 6a - 6b are schematic views of detection means according to the invention along different routes with separate track sections;

[0063] Figs. 7a - 7c show schematic sectional views of different detection means according to the invention with a plurality of optical fibers and at least one cladding structure in a substrate, the optical fibers being arranged partly inside and partly outside the at least one cladding structure.

[0064] Figs. 1a - 1b show schematic views of an embodiment of a linear detection means according to the invention, which is designed as a measuring tape 1. The measuring tape 1 has exactly one measuring section 4, which extends over the entire length of the measuring tape 1.

[0065] Six optical fibers 2, 2', 2" are provided here, one of which is designed as a measuring fiber 14, which has approximately 500 strain sensors 3 arranged at points in the measuring section 4, spaced approximately 20 cm apart. The strain sensors 3 are designed as Fiber Bragg Grating (FBG) sensors. Furthermore, one of the optical fibers comprises temperature sensors 5, which are evenly distributed at a distance of approximately 20 m. The other optical fibers can be used to connect to adjacent measuring sections.

[0066] Fig. 1b shows a cross-section through the measuring tape 1. The optical fibers 2 are embedded parallel to each other in a flat carrier tape 6 made of glass fiber-reinforced polymer. The carrier tape 6 has a width of approximately 8 mm and a thickness of approximately 5 mm. The optical fibers 2 have plug connections at their ends for connection to an optoelectronic interrogation unit 7 or a service box 8.

[0067] Fig. 2 is a schematic view of a measuring tape 1 according to the invention with three measuring sections 4, 4', 4", which are connected in series using two service boxes 8, 8'. In this exemplary embodiment, each measuring section 4, 4', 4" has six optical fibers 2, 2', 2", of which only one is equipped with strain sensors 3, as described in Fig. 1a. In addition, one of the optical fibers 2, 2', 2" of each measuring section 4, 4', 4" is provided with temperature sensors. The service boxes 8, 8' 3. The measuring tape is thus divided into three measuring sections 4, 4', 4", wherein the optical fibers 2, 2', 2" of the measuring sections 4, 4', 4" are led out of the measuring sections 4, 4', 4" and into the service boxes 8, 8' connected in series, namely spliced.

[0068] In this example, an optical fiber configured as a measuring fiber 14 is always connected to an optical fiber not configured as a measuring fiber 14, so that in each measuring section 4, 4', 4", exactly one optical fiber 2, 2', 2" is equipped with strain sensors 3 as a measuring fiber 14. This allows a very long distance to be monitored with several short and essentially identical measuring sections 4, 4', 4", which are connected in series and each have only a limited number, for example, approximately 1000, strain sensors 3.

[0069] 3a - 3b show schematic views of an embodiment of a measuring tape 1 according to the invention. The measuring tape 1 comprises a number N = 10 essentially parallel optical fibers 2 with a multiplicity of FBG strain sensors 3 arranged at specific points. It has ten directly consecutive, non-overlapping measuring sections 4, 4', 4", wherein the optical fibers 2 each have FBG strain sensors 3 in a measuring section, and have no FBG strain sensors 3 outside of this measuring section. For each measuring section 4, 4', 4", approximately 500 FBG strain sensors 3 are provided, which are arranged equidistant from one another and at a distance of approximately 200 cm. Each of the ten measuring sections 4, 4', 4" is thus approximately 1000 m long, and the entire measuring tape 1 extends over a distance of approximately 10 km.

[0070] A further optical fiber is provided, running parallel to the other optical fibers 2, which has temperature sensors 5 evenly distributed along the entire length of the measuring tape 1, which are also designed as FBG sensors. Approximately 200 temperature sensors 5 are provided, arranged equidistantly at a distance of approximately 50 m along the optical fiber 2'.

[0071] Fig. 3b shows a cross-section through the measuring tape 1. The optical fibers 2 are embedded parallel to one another in a flat carrier tape 6 made of glass-fiber-reinforced polymer. Directly consecutive measuring sections 4, 4', 4" are always provided in optical fibers 2 arranged directly next to one another. The carrier tape 6 has a width of approximately 10 mm and a thickness of approximately 1 mm. The optical fibers 2 have plug connections at their ends for connection to an optoelectronic interrogation unit 7 or a service box 8.

[0072] Fig. 4 shows a schematic view of an arrangement of two measuring tapes 1, 1' according to the invention, which are arranged serially along a path using an optoelectronic interrogation unit 7 connected therebetween. The optoelectronic interrogation unit 7 is designed to interrogate all strain sensors 3 of the optical fibers 2 running in the two measuring tapes 1, 1' at a sampling rate of approximately 10 kHz.

[0073] This allows the optoelectronic interrogation unit 7 to provide highly accurate and highly dynamic measurements of mechanical pressures along the track with a resolution of approximately 2 m over a length of approximately 20 km. Furthermore, the optoelectronic interrogation unit 7 can also interrogate the temperature sensors 5 in the optical fiber 2' at high frequency to detect the temperature conditions along the track. Instead of one optoelectronic multi-channel interrogation unit 7, several parallel single-channel interrogation units can also be used.

[0074] In this embodiment, several measuring tapes 1, 1' are arranged in series, with a service box 8 being provided between each two measuring tapes 1, 1' along the route at a distance of approximately 20 km to enable maintenance of the device. In this embodiment, the service box 8 is designed as a connector box into which the optical fibers 2 of the measuring tapes 1, 1' are routed, providing the possibility of connecting an external optoelectronic interrogation unit 7 in the event of a malfunction or for maintenance purposes.

[0075] Fig. 5a is a further schematic view of an arrangement of two measuring tapes 1, 1' according to the invention, which are arranged parallel and offset from one another along a track. In this embodiment, the measuring tapes 1, 1' are used to monitor railway tracks with two rails, in particular for detecting trains and other rail vehicles, and for assessing their running characteristics. Two parallel measuring tapes 1, 1' are provided, which are glued to the two rails. The measuring tapes 1, 1' are arranged offset from one another in the longitudinal direction by half the distance d of the strain sensors 3. The distance d here is approximately 200 cm, so that the measuring tapes 1, 1' are arranged on the rails offset from one another by a distance of approximately 100 cm. This allows position measurement with an accuracy of approximately 100 cm.

[0076] Fig. 5b shows a schematic sectional view of a track with two rails, on the underside of which a measuring tape 1 according to the invention is arranged in a groove 11 of an intermediate layer 10.

[0077] In this embodiment, the two parallel measuring tapes 1, 1' are each located in grooves 11 located on the inner side of the rail. This has the advantage that the measuring tapes 1, 1' experience less wear during operation.

[0078] Fig. 6a shows a schematic view of a device according to the invention which is used to monitor three track sections A, B and C. Switches are provided between the track sections, which are not shown for reasons of clarity. Each of the three track sections has a measuring tape 1, 1', 1". In order to enable continuous monitoring of a rail vehicle traveling on the track, an optical switch 9 is provided which, depending on the position of the switch, connects the first measuring tape 1 to the second measuring tape 1' or to the third measuring tape 1''. The optoelectronic interrogation unit 7 in this exemplary embodiment is designed such that it is able to receive and evaluate the measurement data from both the first measuring tape 1 and the second or third measuring tape 1', 1". Fig.6b shows a further schematic view of a device according to the invention, which is used to monitor three track sections A, B, and C. Between the track sections, switches are again provided, which are not shown for reasons of clarity. Each of the three track sections has a measuring tape 1, 1', 1". In contrast to the embodiment of Fig. 4b, here each measuring tape 1, 1', 1" is equipped with its own optoelectronic interrogation unit 7, 7', 7". To enable continuous monitoring of a rail vehicle traveling on the track, the optoelectronic interrogation units 7, 7', 7" are connected to one another via data lines shown in dotted lines.In this embodiment, the first optoelectronic interrogation unit 7 is designed such that it is able to receive and evaluate the information from the second optoelectronic interrogation unit 7' and the third optoelectronic interrogation unit 7".

[0079] Fig. 7a shows a linear detection means, in particular a measuring tape 1, according to a further embodiment. The detection means has a substrate 12. At least one, in particular two, enveloping structures 13, 13' are embedded in the substrate 12. Outside the enveloping structures 13, 13', an optical fiber 2 designed as a measuring fiber 14 is arranged, in particular embedded in the substrate 12. Within the enveloping structures 13, 13', further optical fibers 2" are arranged, which are sensor-free, in particular not designed as a measuring fiber 14. Optionally, a sensor-free optical fiber 2" can be arranged outside the enveloping structure 13, 13', in particular embedded in the substrate 12. The optical fibers arranged within the enveloping structure 13 are preferably decoupled from the substrate 12, in particular at least mechanically decoupled, in particular decoupled at least in the longitudinal direction of the linear detection means.In particular, these optical fibers 2' are preferably neither force-fitting nor material-fitting connected to the substrate 12 or the enveloping structure 13, 13'. The at least one optical fiber 2, 2" arranged outside the enveloping structure 13, 13' is preferably, in particular directly, integrated into the substrate 12, in particular mechanically coupled thereto, in particular material-fitting and / or force-fitting connected to the substrate 12. This ensures that the optical fiber 2 designed as a measuring fiber 14 can detect strains when a force acts on the substrate 12. The optical fibers 2' arranged in the enveloping structure 13, 13', on the other hand, are decoupled from loads acting on the substrate 12 and are thus particularly resistant to interference and robust in operation.

[0080] Two further embodiments of linear detection means, in particular measuring tapes 1, are described with reference to Fig. 7b and Fig. 7c. In contrast to the embodiment shown in Fig. 7a, a different number and / or arrangement of enveloping structures 13, 13' or optical fibers, in particular measuring fibers 14, is present. Otherwise, the structure and operation correspond to those of the detection means described with reference to Fig. 7a.

[0081] The invention is not limited to the embodiments described above, but encompasses all devices within the scope of the following patent claims.

Claims

Patent claims 1. Linear detection means, in particular measuring tape (1), for detecting loads along a route, in particular a track section, in particular a track rail, comprising a number N of optical fibers (2), where N > 1, 1.1 wherein the detection means has at least one measuring section (4) which extends over at least part of the detection means, 1.2 wherein at least one of the optical fibers (2) is designed as a measuring fiber (14) which has a plurality of point-arranged sensors in the measuring section (4) and has no sensors outside this measuring section (4) and, 1.3 where the maximum dimension of the detection device in a cross-sectional plane is 20 cm.

2. Detection means according to claim 1, characterized in that at least one, in particular several, of the sensors are designed as strain sensors (3), in particular as fiber Bragg grating (FBG) sensors.

3. Detection means according to claim 1 or 2, characterized in that a length of the detection means, in particular of the measuring section (4), is at least 5 m, in particular at least 25 m, in particular at least 100 m.

4. Detection means according to one of the preceding claims, characterized in that the at least one measuring fiber (14) has at least 10, in particular at least 100, of the sensors.

5. Detection means according to one of the preceding claims, characterized by at least one linear sheathing structure (13, 13 '), wherein in the cross-sectional plane at least one of the optical fibers (2) is arranged within the sheathing structure (13, 13 ') and / or the at least one measuring fiber (14) is arranged outside the sheathing structure (13, 13 ').

6. Detection means according to one of the preceding claims, characterized in that the measuring section (4) extends substantially over the entire length of the detection means, wherein only one of the N optical fibers (2) is designed as a measuring fiber (14) with sensors.

7. Detection means according to one of the preceding claims, characterized in that the detection means has at least two of the measuring sections (4, 4', 4"), wherein in each of the measuring sections (4, 4', 4") exactly one optical fiber (2, 2', 2") is designed as a measuring fiber (14) with sensors.

8. Detection means according to one of the preceding claims, characterized in that the number N is at least three, in particular at least five.

9. Detection means according to one of the preceding claims, characterized in that a distance between two adjacent sensors in at least one of the measuring sections (4, 4', 4") is in a range from 1 cm to about 100 m, wherein the sensors in the Measuring section (4, 4', 4") are preferably arranged equidistant from each other.

10. Detection means according to one of the preceding claims, characterized in that at least one of the sensors is designed as a temperature sensor (5).

11. Detection means according to one of the preceding claims, characterized in that the optical fibers (2, 2', 2") are coated with a glass fiber reinforced polymer.

12. Device with at least two of the detection means according to one of the preceding claims and between the detection means at least one single-channel or multi-channel optoelectronic interrogation unit (7) which is designed to interrogate all sensors.

13. Device, with several of the detection means according to one of claims 1 to 11 and between at least two of the detection means a service box (8, 8') for servicing the device.

14. Device having a plurality of the detection means according to one of claims 1 to 11 and at least one optical switch (9) which is designed to automatically reversibly connect the plurality of detection means in a light-conducting manner, in particular to connect them to one another.

15. Device comprising at least one detection means according to one of claims 1 to 11 and a dedicated optoelectronic interrogation unit (7), which is preferably connected to a central data processing unit.

16. Device with at least one detection means according to one of claims 1 to 11 and a control device for continuously detecting the position and / or for assessing the running characteristics of a vehicle, in particular a track vehicle, and / or for assessing the condition of a route, in particular a track section.

17. System, comprising 17.1 at least one extensive structure, such as an engineering structure, a road, a pipeline, a cable, a structure or a track, 17.2 at least one detection means according to one of claims 1 to 11, wherein the detection means is connected to the structure in a materially bonded and / or force-locked manner.

18. System according to claim 17, characterized in that the at least one extended structure is a track.

19. System according to claim 18, characterized in that the track comprises a track rail, wherein the detection means is arranged on an underside of the track rail.

20. System according to claim 18 or 19, characterized in that the track comprises a track rail, a base and an intermediate layer arranged between the track rail and the base, wherein the detection means is arranged on the intermediate layer (10), in particular in a groove (11) of the intermediate layer (10).

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