Acoustic leakage marker, leakage detection system, method, and use

Abstract

The invention relates, inter alia, to an acoustic leakage marker (110) for transmitting a reference signal (200) to a line (400) carrying a medium (500). The acoustic leakage marker (110) comprises a sound generator (140) for generating a reference signal; and a sound transfer structure (130) which is in contact with the sound generator and is designed to be in direct contact with the line (400) when the leakage marker (110) is mounted on the line (400) such that the reference signal (200) is transmitted from the sound generator (140) to the line (400) via the sound transfer structure (130). The invention further relates to a leakage detection system, to a method, and to uses of the acoustic leakage marker and the leakage detection system.

Description

[0001] KM / rc 241143W0

[0002] January 6, 2026

[0003] Acoustic leakage marker, leakage detection system, method and use

[0004] The present invention relates to an acoustic leakage marker. The present invention further relates to a leakage detection system, a method, and a use.

[0005] Leaks in pipelines, such as water pipes (raw water, process water, drinking water, or wastewater pipes), but also generally in pipelines for transporting liquid or gaseous media, must be avoided to prevent economic or environmental damage. Such pipeline networks, like the water supply network, enable the supply of valuable resources to the population and also the disposal of media.

[0006] Taking the water supply network as an example, leaks in these networks can be responsible for losses of up to 50% of the supplied volume. Even in very well-developed networks, such as the water supply networks in Germany or the Netherlands, leaks account for losses of approximately 5% of the supplied volume. This not only results in an increased financial burden for consumers but also has a negative impact on the environment.

[0007] Such leaks can be acoustically detected using inline inspection robots. A sound detector on the inspection robot picks up noises that can be measured within the pipe. Leaks typically produce clearly identifiable leakage noises that can be identified during the measurement.

[0008] However, existing systems have the disadvantage that their functionality cannot be reliably verified. For example, if the system does not detect any leaks, it is unclear whether the acoustic detector is faulty or whether there are actually no leaks in the pipe section.

[0009] Furthermore, it is not yet possible to always pinpoint detected leaks exactly, as the position of the inspection robot within the pipe cannot always be reliably determined.

[0010] Against this background, the present invention aims to improve the detection of leaks in pipes.

[0011] In a first aspect, the aforementioned problem is solved according to the invention by an acoustic leakage marker for transmitting a reference signal to a conductor carrying a medium. The acoustic leakage marker comprises a sound transmitter for generating a reference signal. The acoustic leakage marker further comprises a sound transfer structure in contact with the sound transmitter. The sound transfer structure is configured to be in direct contact with the conductor when the leakage marker is mounted on the conductor, so that the reference signal is transmitted from the sound transmitter to the conductor via the sound transfer structure.

[0012] As will be explained in more detail below, the (acoustic) reference signal is understood to be, in particular, a signal that simulates a leakage noise in the line. Alternatively or additionally, a reference signal can also be a signal that differs from a leakage noise and, for example, allows for easy identification of the reference signal as such.

[0013] The reference signal is generated by the sound source. A sound source can be, for example, a piezoelectric element, a loudspeaker, a linear resonant actuator, or a structure-borne sound transducer. The sound source can be connected to a control unit (such as one integrated into the leakage marker or an external control unit) which provides the reference signal.

[0014] KM / rc 241143WO January 6, 2026 Leakage markers can, for example, generate different reference signals.

[0015] For example, a user can specify different reference signals or select one from a plurality of preset reference signals.

[0016] For example, different reference signals can be stored specifically for a particular line and / or guided medium. The reference signal generated by the sound transducer can, for instance, take into account the transfer function from the transducer to the sound transfer structure and / or the transfer function from the sound transfer structure to the line.

[0017] The sound transducer is in contact with the sound transfer structure. This allows (acoustic) excitations from the transducer to be transferred to the sound transfer structure. The sound transfer structure can be, in particular, a primarily mechanical structure. Specifically, the sound transfer structure can have a part that is fixed relative to the conductor when mounted and a part that is movable relative to the conductor (such as a plunger), which transmits the generated reference signal to the conductor. The transmission thus occurs essentially through a purely mechanical excitation of the conductor by the sound transfer structure.

[0018] The leak detector can be mounted on the pipe, for example, by placing it on the outside of the pipe. Alternatively, the leak detector can also be fixed to the opposite side of the pipe, for example, with clamps or clips ("clamp-on"). This mounting method is particularly non-invasive, meaning the leak detector does not penetrate the pipe.

[0019] The pipe can be, for example, a conduit. As will be explained in more detail below, the pipe can be made of various materials, such as plastic, in particular PVC, HDPE, glass fiber reinforced epoxy (GRE), or concrete, or metal, in particular steel or cast iron. The leakage marker described herein is particularly important due to its direct contact with the

[0020] KM / rc 241143WO 6 January 2026 The advantage of the standing sound transfer structure is that it can be used for lines made of different materials, especially for lines made of metal as well as for lines made of concrete.

[0021] In a second aspect, the aforementioned problem is further solved according to the invention by a leak detection system comprising an acoustic leakage marker of the first aspect and a measuring device for recording the reference signal that was transmitted from the acoustic leakage marker to the line.

[0022] In a third aspect, the aforementioned problem is further solved according to the invention by a method for transmitting a reference signal to a conductor carrying a medium. The method comprises mounting an acoustic leakage marker, particularly according to the first aspect, with a sound transmitter for generating a reference signal and with a sound transfer structure in contact with the sound transmitter, onto the conductor, such that the sound transfer structure is in direct contact with the conductor. The method further comprises generating the reference signal with the sound transmitter, such that the reference signal is transmitted from the sound transmitter to the conductor via the sound transfer structure.

[0023] In a fourth aspect, the aforementioned problem is further solved according to the invention by using the acoustic leakage marker of the first aspect to transmit a reference signal to a line.

[0024] In a fifth aspect, the aforementioned problem is further solved according to the invention by using the leakage detection system of the second aspect to verify a function of the measuring device using the reference signal and / or to generate at least one reference value in a measurement of the measuring device using the reference signal. The (temporally or spatially localized) reference value can be used, for example, for calibrating or adjusting the measuring device.

[0025] KM / rc 241143WO January 6, 2026 The following describes various embodiments of the acoustic leakage marker, the leakage detection system, the method, and the uses, whereby the features of the individual embodiments also apply accordingly to the other aspects (i.e., to the acoustic leakage marker, the leakage detection system, the method, and the uses). Furthermore, the individual embodiments can also be combined with one another as desired.

[0026] As previously described, the task is solved by using an acoustic leakage marker, as described in the first aspect, to transmit a reference signal to a line. According to the fourth aspect, the acoustic leakage marker can be used to transmit the reference signal to a line. In particular, the reference signal can be transmitted to the line using a method for transmitting the reference signal, as described in the third aspect.

[0027] The leak detection system according to the second aspect includes, in addition to the acoustic leakage marker according to the first aspect, a measuring device. The measuring device can be configured to measure a leakage noise that occurs when a medium carried in a pipe escapes through a leak in the pipe. Furthermore, the measuring device can be configured to measure a reference signal transmitted to the pipe by the acoustic leakage marker. Thus, the leak detection system can be used to detect any leaks that may be present in a pipe and also to record the reference signal. For the purposes of this application, the terms record, detect, measure, and perceive are to be used synonymously. In particular, one term can encompass the other terms.

[0028] In one exemplary embodiment, the measuring device is configured to be moved by a cable. This can be done actively, for example, by its own drive, such as a propeller, or passively by a drive via the cable.

[0029] KM / rc 241143WO January 6, 2026. This is caused by the flowing medium. As the measuring device moves through the pipe, it can measure noises occurring along the pipe with temporal (and thus spatial) resolution. A temporally resolved measurement of the noises occurring in the pipe can therefore show which noises are perceptible at different points within the pipe. For example, a measuring device might pass a leak in a pipe after a time t of measurement. Accordingly, the measurement after time t could show a leak noise caused by the leak. In that case, the position of the leak could be determined using the time t of the leak noise occurring in the measurement and the position of the measuring device at that time.

[0030] A reference signal transmitted into the pipe by the acoustic leak detector can therefore be measured by the measuring device in the vicinity of the acoustic leak detector. If the position of the acoustic leak detector on the pipe is known, it can be determined from the time at which the reference signal was measured by the measuring device that the measuring device was located within the pipe near the position of the acoustic leak detector at that time. This facilitates the localization of the measuring device and, consequently, the localization of any leakage noise that may be occurring.

[0031] Furthermore, the reference signal can be used to verify the functionality of the measuring device. This is achieved by having the acoustic leakage marker transmit the reference signal into a line containing the measuring device. If the measuring device has passed the acoustic leakage marker but has not received the reference signal, this may indicate that the measuring device is defective and / or faulty. However, if the measuring device was able to detect the reference signal, this can be used as proof of its functionality.

[0032] KM / rc 241143W0 January 6, 2026 In a further exemplary embodiment, the measuring device can be calibrated using the reference signal. In particular, a frequency spectrum of the reference signal can be known and compared with a frequency spectrum of a measurement of the reference signal by the measuring device. Preferably, this enables subsequent calibration of the measuring device, in which the measuring device is used to measure a line and, after completion of the measurement, a reference signal measured during the measurement is used to calibrate corresponding measured values.

[0033] As previously described, the function of the measuring device can thus be verified using the reference signal by employing the leakage detection system in accordance with the fifth aspect. Furthermore, a reference value can be generated in a measurement of the measuring device using the reference signal and the leakage detection system in accordance with the fifth aspect.

[0034] In one exemplary embodiment, the acoustic leakage marker is configured to transmit a reference signal to a conductor. Transmitting the reference signal to the conductor can, for example, include transmitting the reference signal into the medium carried by the conductor. In other words, the reference signal can, for example, penetrate a medium contained within the conductor. The reference signal can thus propagate through the conductor and / or the medium. Since sound propagates in all directions, transmitting the reference signal to the conductor may, in particular, be sufficient to transmit the reference signal into the medium. This allows the reference signal to be measured and / or detected within the conductor.

[0035] In one exemplary embodiment, the reference signal corresponds to a leakage noise that occurs when the medium carried by the line escapes through a leak in the line. For example, the reference signal can be based on a recording of an actual leakage noise (e.g., regarding the

[0036] KM / rc 241143WO January 6, 2026 (specific pipe and / or medium). For example, the reference signal can be synthesized in such a way that it corresponds to a leakage noise (at least with respect to certain properties). The reference signal can correspond to a predefined leakage noise (which can be specific to or independent of the specific pipe and / or medium). In other words, the reference signal can imitate a typical leakage noise.

[0037] For example, the reference signal has a frequency spectrum that corresponds to the frequency spectrum of a leakage noise, exhibiting, for instance, the same characteristic frequency distribution. This makes the reference signal particularly suitable for verifying the function of a measuring device, e.g., according to the second aspect.

[0038] Alternatively or additionally, in another exemplary embodiment, the reference signal has a predefined or unique acoustic signature.

[0039] For example, the reference signal has a frequency spectrum that can be uniquely assigned to it. In particular, the reference signal can have a frequency spectrum that can be distinguished from naturally occurring noises (especially leakage noises) (for example, at least partially outside the frequency range of naturally occurring leakage noises). Thus, the reference signal can be identified as such in a measurement by a measuring device, e.g., the measuring device of the leakage detection system, according to the second aspect.

[0040] In one example, the reference signal can have one or more frequencies in the range of 0.1–100 kHz. The frequency or frequencies of the reference signal are selected or determined, for example, based on the material of the pipeline, the size of the pipeline, the medium being conveyed, and / or the size of the leak to be simulated. For example, in a lower part of the frequency range, the reference signal corresponds to the leak noise, as described above. Similarly, in a higher part of the frequency range, the reference signal exhibits an acoustic signature, as described above.

[0041] KM / rc 241143W0 January 6, 2026 In an example, the reference signal is a clocked reference signal. The reference signal is, for example, periodically switched on for a first time and switched off for a second time. The first and / or the second time is, for example, less than 10 s, preferably less than 5 s, and further preferably less than 1 s.

[0042] For example, the first and / or second time is 0.1s, 0.25s or 0.5s.

[0043] Leakage noises, and thus the reference signal, are typically detected for a period of 20 to 40 seconds (at a typical speed of the measuring device, such as an inspection robot, in the pipeline of approximately 0.5 m / s). During this time, the timing of a corresponding reference signal can be reliably detected, and the reference signal can be reliably distinguished from actual leaks and identified as such.

[0044] In one exemplary embodiment, the reference signal comprises a combination of a leakage noise and a predefined acoustic signature. As previously explained, the predefined acoustic signature can be located, at least partially, in a frequency range that lies outside the substantial frequency range of a naturally occurring leakage noise. Thus, the reference signal can be used to verify the function of a measuring device, e.g., according to the second aspect, with the predefined acoustic signature facilitating identification of the reference signal.

[0045] In an exemplary embodiment, the frequency spectrum of the reference signal (at least the part of the reference signal corresponding to a leakage noise) exhibits frequencies below 24 kHz, particularly below 20 kHz, and preferably below 15 kHz, at least partially, and in particular at least half of, and preferably predominantly. When a medium escapes from a pipe, the frequency spectrum of the associated leakage noise depends on the pipe material, the medium, the pressure within the pipe, and the size and shape of the leak. This is particularly true for water pipes, where such noises typically occur.

[0046] KM / rc 241143WO January 6, 2026 Frequency spectra with a significant component below a frequency of 24 kHz. Provided the reference signal is essentially a

[0047] If the reference signal is intended to correspond to the leakage noise that occurs when the medium carried in the pipe escapes through a leak, it is advantageous if the frequency spectrum of the reference signal also includes at least some frequencies below this frequency in order to verify the function of a measuring device. As already explained, the frequency spectrum can, however, also include frequencies above these frequencies (i.e., in particular above 24 kHz), especially if the reference signal is to have a predefined acoustic signature that identifies the reference signal as such, as described above.

[0048] According to the first aspect, the acoustic leakage marker has a sound transmitter. The sound transfer structure is designed to transmit the reference signal (directly) from the sound transmitter to a conduit on which the sound transfer structure is mounted.

[0049] Sound can be transmitted in several different ways.

[0050] For example, ultrasound can be indirectly transmitted to a test object via a gel, as is known in the medical field. However, it has been found that direct and / or mechanical transmission from the sound transfer structure to the conductor is particularly well-suited for transferring a reference signal to the conductor. In one exemplary embodiment, the sound transfer structure includes a plunger which, when the leakage marker is mounted, is designed to make direct contact with the conductor. For example, the transducer is arranged in contact with the plunger. Thus, the reference signal can be transmitted from the transducer to the conductor via the plunger in a direct mechanical manner. This allows sound to be transmitted to a conductor non-invasively, particularly for any conductor material and any frequency spectra of the reference signal.

[0051] KM / rc 241143WO January 6, 2026. For example, it has been found that the transmission of ultrasound using a gel is not satisfactory with some pipe materials. In particular, with concrete pipes, it has been found that due to the high absorption of ultrasound by concrete, sufficient transmission or propagation of the sound in or through the concrete pipe cannot be guaranteed. The sound transfer structure described above enables effective transmission of sound to different pipe materials.

[0052] In one exemplary embodiment, the plunger has a contact surface, and the plunger is configured, in a state where the leakage marker is mounted on the line, to make direct contact with the line via the contact surface. The contact surface can be adapted to the shape of the line to ensure reproducible direct contact between the plunger and the line. For example, the size and shape of the contact surface can be adapted to optimize the transmission of the reference signal to a line.

[0053] In another exemplary embodiment, the contact surface of the plunger (for example, in at least one dimension) corresponds to the area of ​​a predefined leak in the line. The area of ​​the predefined leak can, for example, correspond to a typical or average leak area (such as occurs in the specific line). It has been found that a reference signal transmitted to a line reproduces a leak noise particularly realistically when the contact surface of the plunger with which the reference signal is generated has similar dimensions to a typical leak in the line. Thus, the reference signal can be used particularly well for verifying the function of a measuring device, e.g., the measuring device of the leak detection system of the second aspect.

[0054] In one exemplary embodiment, the sound transfer structure includes a means for exerting a force on the plunger. For efficient mechanical

[0055] KM / rc 241143WO January 6, 2026 For the transmission of sound to pipes, good contact between the plunger and the pipe can be advantageous. The means of exerting force can ensure good contact between the plunger and the pipe. In particular, the force is exerted in the direction of the pipe when the sound transmission structure is mounted. In other words, when the leakage marker is mounted, the plunger experiences a force in the direction of the pipe. This allows the plunger to be pressed against the pipe. In other words, the plunger thus experiences a contact force against the pipe. This can, in particular, enable good contact between the plunger and the pipe and thus efficient transmission of sound to the pipe. For example, the means of exerting force includes a spring, such as a compression spring, and / or an elastic material, such as rubber or a synthetic elastomer, such as silicone or polyurethane.The spring and / or elastic material can, for example, be positioned between a part that is fixed relative to the conductor in the assembled state and the plunger, which is movable relative to the conductor. A spring and / or elastic material allows a force to be exerted on the plunger continuously or repeatedly. Furthermore, a spring or elastic material does not require a power supply and is therefore less prone to failure.

[0056] In one exemplary embodiment, the sound transfer structure comprises a diaphragm arranged in direct contact with the plunger. The diaphragm can, for example, amplify a reference signal generated by the sound transducer. Furthermore, the diaphragm can transmit a reference signal generated by the sound transducer to the plunger. For this purpose, in one exemplary embodiment, the sound transducer is at least partially arranged on the diaphragm.

[0057] In one exemplary embodiment, the sound transmitter comprises a piezoelectric element, a loudspeaker, a linear resonant actuator, and / or a structure-borne sound transducer. In another exemplary embodiment, the sound transmitter consists of just one of these elements. The use of a piezoelectric element as the sound transmitter has proven to be particularly advantageous, especially since

[0058] KM / rc 241143WO January 6, 2026 Piezoelectric elements are particularly efficient and compact and can generate sound across a wide frequency range. Through a loudspeaker, a linear resonance actuator, and / or a structure-borne sound transducer, the sound generator can produce the reference signal with exceptional efficiency and / or high quality.

[0059] In one exemplary embodiment, the sound transmitter comprises a piezoelectric element as well as a loudspeaker, a linear resonant actuator, and / or a structure-borne sound transducer. In this way, the advantages of different sound transmitters can be combined.

[0060] In one exemplary embodiment, the sound transmitter comprises a piezoelectric element in direct contact with the plunger. In another exemplary embodiment, the sound transmitter further comprises a loudspeaker, a linear resonant actuator, and / or a structure-borne sound transducer, which is / are at least partially arranged on the diaphragm. It has surprisingly been found that such a configuration of the sound transmitter is particularly advantageous in that a particularly accurate reference signal can be generated and the transmission of the reference signal through the plunger to a corresponding line is particularly efficient.

[0061] In one exemplary embodiment, the measuring device is designed to be arranged in a pipe. For example, the measuring device can be designed to be loosely inserted into a pipe. For this purpose, the measuring device can have a size adapted to the corresponding pipe. In particular, the measuring device can be designed to move through a pipe.

[0062] Basically, the measuring device is designed to record noise in a pipe. In other words, the measuring device is designed, for example, to record noise in the medium contained in the pipe. For example, the measuring device is designed to...

[0063] KM / rc 241143WO January 6, 2026 To record the reference signal transmitted from the acoustic leakage marker to the pipe. In particular, the measuring device may be configured to record not only the reference signal, but also leakage noises in the pipe in general. This allows the measuring device to record noises that are only measurable in the pipe. For example, the measuring device may contain and / or have a hydrophone if the measuring device is used in a drinking water pipe.

[0064] In one exemplary embodiment, the pipe material may contain or be metal, plastic, asbestos, and / or concrete. In another exemplary embodiment, the medium may contain or transport a gas or a liquid, in particular water (such as raw water, process water, tap water, drinking water, or wastewater). In other words, the leak detection system can be configured to examine various pipes made of different materials, which in particular carry different media, for leaks. Furthermore, the acoustic leak marker can be configured to be used for different pipes and / or media. This allows the leak detection system or the acoustic leak marker to be used in a particularly versatile manner. As already mentioned, it is conceivable that the leak marker or the leak detection system is designed to generate different reference signals.The individual reference signals can be adapted, in particular, for different conductors and / or materials.

[0065] Further features and advantages of the acoustic leakage marker, the leakage detection system, the method and the uses will become apparent from the following description of exemplary embodiments, with reference to the accompanying drawing.

[0066] The drawing shows

[0067] KM / rc 241143WO 6 January 2026 Fig. 1 a cross-sectional view of an exemplary embodiment of an acoustic leakage marker, mounted on a pipe;

[0068] Fig. 2a-c Cross-sectional views of various exemplary embodiments of the acoustic leakage marker;

[0069] Fig. 3 shows a schematic representation of an exemplary process; and

[0070] Fig. 4a-c schematic representations of an exemplary leak detection system, as well as exemplary uses of an exemplary acoustic leakage marker and an exemplary leak detection system.

[0071] Fig. 1 shows a cross-sectional view of an exemplary embodiment of an acoustic leakage marker 110. The acoustic leakage marker 110 is mounted on an outer wall of a pipe 400 (only a portion of the pipe is visible in Fig. 1). The pipe 400 contains a medium 500, which is not shown in the figure. The medium 500 could, for example, be a liquid (such as water, raw water, process water, drinking water, or wastewater) or a gas that is to be supplied to a customer.

[0072] The acoustic leakage marker 110 comprises a sound transducer 140 and a sound transfer structure 130, wherein the sound transducer 140 is arranged in contact with the sound transfer structure 130. The sound transducer 140 is configured to generate a reference signal 200 (schematically shown in Fig. 4a-c). In Fig. 1, the sound transducer 140 is shown as an example of a piezoelectric element. Alternatively, the sound transducer 140 can also be a loudspeaker, a linear resonant actuator, or a structure-borne sound transducer. Furthermore, it is also possible for the sound transducer 140 to be a combination of the aforementioned elements. For example, the sound transducer 140 can contain both a piezoelectric element and a loudspeaker.

[0073] KM / rc 241143W0 January 6, 2026 To supply the sound transmitter 140 with electrical power, the acoustic leakage marker 110 also has a power source 122. In Fig. 1, the power source 122 is shown by way of example as an arrangement of four batteries. However, any other power source 122 is equally suitable for supplying the sound transmitter 140 with electrical power. In addition, the acoustic leakage marker 110 has a circuit board 120 for controlling the sound transmitter 140. The circuit board 120 and the power source 122 are connected to the sound transmitter 140 via cables 124.

[0074] Furthermore, Fig. 1 shows, by way of example, that the acoustic leakage marker 110 has a GPS module 126. The GPS module 126 can be used to uniquely locate the acoustic leakage marker 110. This allows the absolute position of the leakage marker 110 on the line (and thus the coupling of the reference signal) to be determined. In addition, the acoustic leakage marker 110 can be more easily located after use, and its position can be digitally retrieved during operation.

[0075] The sound transfer structure 130 is designed to be mounted in direct contact with a conductor 400. Figure 1 shows an example of how the sound transfer structure 130 is mounted in direct contact with the conductor 400. For this purpose, as shown in Figure 1, a housing 112 with dampers 114 can be attached to a surface of the conductor 400. A means for locking the housing 112 to the conductor 400 is not shown in Figure 1, but could, for example, include a clamp or similar means.

[0076] The sound transfer structure 130 is designed to transfer the reference signal 200 in a mounted state from the sound transmitter 140 to a line 130, on which the leakage marker 110 is mounted with the sound transfer structure 130.

[0077] In particular, the sound transfer structure 130 is configured to transmit the reference signal 200 directly to the line 130. This is achieved by the fact that the sound transmitter 140 is in

[0078] KM / rc 241143WO January 6, 2026 When the sound transfer structure 130 is in contact with the sound transfer structure 130 and the sound transfer structure 130 is in direct contact with the line 400, sound, such as the reference signal 200, can propagate particularly efficiently from the sound transmitter 140 through the sound transfer structure 130 to the line 400.

[0079] The sound transfer structure 130 comprises a plunger 134 which, in the assembled state of the sound transfer structure 130, is designed to directly contact the line 400. In Fig. 1, the plunger 134 is in direct contact with the line 400. Furthermore, the plunger 134 is in contact with the sound transmitter 140, enabling the plunger 134 to efficiently transfer sound from the sound transmitter 140 to the line 400.

[0080] The plunger 134 has a contact surface 136. In the assembled state of the sound transfer structure 130, the plunger 134 is designed to make direct contact between the conductor 400 and the contact surface 136. Figure 1 shows how the plunger makes contact between the conductor 400 and the contact surface 136. In particular, the contact surface 136 lies flat on the surface of the conductor 400, as this allows for particularly efficient transmission of sound to the conductor 400.

[0081] In an advantageous embodiment, the contact surface 136 is similar in at least one dimension to the surface of a typical leak 410 in the line 400. Such a leak 410 is shown schematically in Fig. 4a-c. This allows an average leakage noise of the line to be simulated particularly precisely by a reference signal 400 generated by the sound transmitter 140.

[0082] As shown in Fig. 1, the sound transfer structure 130 further comprises a means 138 for exerting a force on the plunger 134. The means 138 for exerting a force is a compression spring in Fig. 1. Due to the cross-sectional view shown in Fig. 1, only cross-sections of individual coils of the spring are shown as examples.

[0083] KM / rc 241143WO, January 6, 2026. However, it would also be conceivable to use an elastic material as an alternative or in addition to the spring.

[0084] The force exerted by the spring on the plunger is directed towards the line 400. As shown in Fig. 1, the plunger 134 and the spring are arranged in a cylinder 131 with a cap 132. The spring is clamped between the cap 132 and the plunger 134. This causes the spring to push the plunger 134 away from the cap 132, thereby pressing the plunger 134 against the line 400. The force with which the plunger 134 is pressed against the line 400 can be adjusted by selecting a suitable spring.

[0085] In particular, the force can be sufficient to ensure that the plunger 134 remains in continuous, direct contact with the line 400 even during sound transmission from the sound transmitter 140 to the line 400. This allows for particularly efficient and precise sound transmission. Alternatively, the force can be set such that the plunger 134 vibrates during sound transmission and strikes the line 400 synchronously with the vibration of the sound.

[0086] Figures 2a-c show various embodiments of the acoustic leakage marker 110. In particular, the embodiments shown in Figures 2a-c are modifications of the acoustic leakage marker 110 in Figure 1. Figure 2a shows a section of the acoustic leakage marker 110 as shown in Figure 1.

[0087] Fig. 2b shows a section of another exemplary acoustic leakage marker 110. In Fig. 2b, the sound transfer structure 130 comprises a diaphragm 142. The diaphragm 142 is arranged in direct contact with the plunger 134. The diaphragm 142 is stretched over a recess in the plunger 134. The sound transducer 140 is arranged on the diaphragm 142. This allows sound generated by the sound transducer 140 to be amplified via the diaphragm 142 and transmitted to the plunger 134.

[0088] KM / rc 241143W0 January 6, 2026 As described in Fig. 1, the sound transmitter 140 in Fig. 2b can also be, comprise, or correspond to a piezoelectric element, a loudspeaker, a linear resonance actuator and / or a structure-borne sound transducer.

[0089] Fig. 2c shows another exemplary embodiment of the acoustic leakage marker 110. The sound transfer structure 130 has a diaphragm 142, as in Fig. 2b. In Fig. 2c, two sound transducers 140, 140' are provided. The sound transducer 140 is a piezoelectric element arranged in direct contact with the plunger 134. The sound transducer 140' is arranged on the diaphragm 142. The sound transducer 140' can be, comprise, and / or correspond to a loudspeaker, a linear resonant actuator, and / or a structure-borne sound transducer. This arrangement makes it possible to generate a particularly precise reference signal 200.

[0090] Fig. 3 shows an embodiment of method 600 for transmitting a reference signal to a line 400.

[0091] Step 610 of the method 600 comprises: mounting an acoustic leakage marker 110 onto a line 400. The acoustic leakage marker 110 can, in particular, be an acoustic leakage marker according to Fig. 1 or Fig. 2a-c. By performing step 610, for example, the state shown in Fig. 1 can be achieved.

[0092] Step 620 comprises: generating a reference signal 200 with the sound transmitter 140, so that the reference signal 200 is transmitted to the line 400. As described in Fig. 1, the sound transfer structure 130, in particular the plunger 134, can transmit the reference signal 200 generated by the sound transmitter 140 to the line 400. This allows, in particular, the reference signal 200 to be introduced into the medium 500, as shown below in Figs. 4a-c.

[0093] KM / rc 241143WO January 6, 2026. Figures 4a-c show exemplary embodiments of the acoustic leakage marker 110, the leakage detection system 100, the method 600 for transmitting a reference signal 200 to a line 400, and the uses of the acoustic leakage marker 110 and the leakage detection system 100. The acoustic leakage marker 110 and the method 600 can correspond to the embodiments shown in the preceding figures.

[0094] Figures 4a-c show, in particular, a pipe 400 containing a medium 500. The medium 500 can contain at least one gas or liquid (especially water). For example, the medium 500 shown in Figures 4a-c is drinking water. Accordingly, the pipe 400 is, for example, a drinking water pipe, for instance, for a public water supply. The pipe 400 shown could therefore be part of a drinking water distribution network.

[0095] Typical drinking water supply networks experience losses of 5-50% due to leaks. In some countries, such as Germany or the Netherlands, average values ​​are around 5%, while other countries can have higher average values, for example, 40-50% in Italy and about 30% in Portugal. An example of a leak is shown in Fig. 4a-c, where the medium 500 unintentionally escapes through a leak 410 in pipe 400. The representation is purely schematic and not suitable for scaling.

[0096] To remedy losses caused by leaks, it is necessary to inspect pipes for leaks and, if found, to locate them. Leaks that have been located can be repaired. Alternatively, leaking sections of pipe can be replaced.

[0097] To detect leaks, the leak detection system 100 includes a measuring device 150. The measuring device 150 is designed to be installed in a line 400. Furthermore, the measuring device 150 is designed to record noise in a line 400. In particular, the

[0098] KM / rc 241143WO January 6, 2026 Measuring device 150 set up to record a leakage noise 300 caused by the escape of the medium 500 through a leak 410.

[0099] The leak detection system 100 also includes an acoustic leakage marker 110. The acoustic leakage marker 110 is, for example, an acoustic leakage marker 110 as shown in Figs. 1, 2a-c. The acoustic leakage marker 100 has been mounted on the line 400, for example, according to step 610. In addition, the sound transmitter 140 (see Figs. 1, 2a-c) generates a reference signal 200 according to step 620, which is transmitted by the sound transfer device 130 (see

[0100] Fig. 1, 2a-c) is transmitted to line 400. The measuring device 150 is configured to receive the reference signal 200, which was transmitted from the acoustic leakage marker 110 to line 400.

[0101] The pipe 400, for example, is made of plastic. However, the pipe 400 can also contain metal, asbestos, and / or concrete. Since the reference signal 200 is mechanically transferred to the pipe 400 by the sound transfer structure 130, in particular by the plunger 134, the pipe 400 can, in principle, contain any material suitable for its construction. This prevents the leak detection system 100 from being unusable for pipes 400 made of certain materials, as is the case, for example, when transferring a reference signal 200 with ultrasound and an ultrasonic gel to concrete pipes.

[0102] Figures 4a-c accordingly show the use of the acoustic leakage marker 110 to transmit a reference signal 200 to a line 400. The reference signal 200 is to be measured, in particular, by the measuring device 150. Figures 4a-c also show the use of the leakage detection system 100 to verify a function of the measuring device 150 using the reference signal 200 and / or to generate at least one local reference value in a measurement of the measuring device 150 using the reference signal 200.

[0103] KM / rc 241143WO January 6, 2026 In Fig. 4a, the measuring device 150 has been inserted into the left end of the line 400 and thus also into the medium 500. The measuring device 150 is specifically designed to be able to record noise in the medium 500. For example, the measuring device 150 has a hydrophone to be able to record noise in the medium 500 (drinking water).

[0104] In Fig. 4a, the measuring device 150 is not located near the acoustic leakage marker 110 or the leak 410. Therefore, the measuring device 150 does not record any noise that would indicate a leak. This is shown schematically in diagram 700a, where the measured intensity I is plotted against the sound frequency f. The measurement shown is purely exemplary and should be considered in comparison with diagrams 700b and c from Figures 4b and c.

[0105] The measuring device 150 is further equipped to record noises that may arise from the movement of the medium 500 through the line 400, such as gurgling air bubbles, the noise of the medium 500 along a wall of the line 400, or splashing against a wall of the line 400. However, these noises are not considered here and are therefore not shown in diagrams 700a-c. For example, these noises are subsequently detected and removed from measurements by suitable software in order to obtain only recorded leakage noises 300 or reference signals 200.

[0106] Alternatively, recorded leakage noises 300 or reference signals 200 from the measurement are subsequently identified and / or extracted from measurements using suitable software.

[0107] In Fig. 4b, the measuring device 150 is located near the acoustic leakage marker 110. The measuring device 150 can detect and / or record the reference signal 200 transmitted from the acoustic leakage marker 110 to the line 400 in the medium 500. An exemplary measurement of the

[0108] KM / rc 241143WO 6 January 2026Reference signal 200 through the measuring device 150 is shown, for example, in diagram 700b.

[0109] The reference signal 200 shown in Fig. 4b is similar to a leakage noise 300 (see Fig. 4c) that occurs when a medium 500 carried by a line 400 escapes from the line 400 through a leak 410 in the line 400. In other words, the reference signal 200 imitates a leakage noise 300. Alternatively or additionally, the reference signal 200 contains or corresponds to a unique acoustic signature.

[0110] A frequency spectrum of the reference signal 200 (example shown in diagram 700b) exhibits at least partially, in particular at least half, preferably predominantly, frequencies below 24 kHz, particularly below 20 kHz, and preferably below 15 kHz. Typical leakage noises 300 in conventional water pipes lie largely within a frequency range below 24 kHz. Therefore, limiting the reference signal 200 to this frequency range can be particularly advantageous in order to imitate or closely resemble a leakage noise 300 from a water pipe.

[0111] When the measuring device 150 is used to check a line 400 for leaks, it is possible that the line 400 has no leaks and is completely intact. Since a resulting measurement cannot always be easily distinguished from a measurement in which the measuring device 150 is defective or faulty and has not measured existing leaks due to the defect, recording the reference signal 200 by the measuring device 150 (as shown in diagram 700b) can be used as evidence that the measuring device 150 is not defective or faulty.

[0112] The leak detection system 100 (acoustic leakage marker 110 and measuring device 150) can therefore be used as a function of the

[0113] KM / rc 241143WO January 6, 2026 Measuring device 150 can be checked using the reference signal 200. Alternatively, the acoustic leakage marker 110 can be used to check a function of the measuring device 150 using the reference signal 200.

[0114] In Fig. 4c, the measuring device 150 is located near the leak 410 through which some of the medium 500 escapes from the line 400. A resulting leakage noise 300 is measurable near the leak and is recorded by the measuring device 150. An example of a resulting measurement is shown in diagram 700c.

[0115] The leak detection system 100 (acoustic leakage marker 110 and measuring device 150) can be used to generate a local reference value in a measurement of the measuring device 150. In particular, the reference signal 200 can be used to generate at least one local reference value in a measurement of the measuring device 150. Alternatively or additionally, the acoustic leakage marker 110 can be used to generate at least one local reference value in a measurement of the measuring device 150.

[0116] The local reference value can be generated, for example, by knowing the precise position of the acoustic leakage marker 110, such as by the GPS module 126 shown in Fig. 1. When the reference signal 200 is detected in a measurement by the measuring device 150, the time of the measurement of the reference signal 200 can be correlated with the position of the acoustic leakage marker 110. If a leakage noise 300 was measured temporally before the reference signal 200, a corresponding leak is located upstream of the acoustic leakage marker 110 along the direction of movement of the measuring device 150. Thus, a detected leak can be more easily located using a local reference value generated in this way.

[0117] KM / rc 241143W0 January 6, 2026

Claims

KM / rc 241143W0 January 6, 2026 Patent claims 1. Acoustic leakage marker (110) for transmitting a reference signal (200) to a line (400) carrying a medium (500), wherein the acoustic leakage marker (110) comprises: a sound transmitter (140) for generating a reference signal; and a device in contact with the sound transmitter Sound transfer structure (130), which is designed to be in direct contact with the line (400) when the leakage marker (110) is mounted on the line (400), so that the reference signal (200) is transmitted from the sound transmitter (140) to the line (400) via the sound transfer structure (130).

2. Acoustic leakage marker (110) according to claim 1, wherein the reference signal (200) corresponds to a leakage noise (300) that occurs when the medium (500) carried by the line (400) escapes from the line (400) through a leak (410) in the line (400), and / or wherein the reference signal (200) corresponds to a predefined leakage noise (300); and / or wherein the reference signal (200) has a predefined acoustic signature which identifies the reference signal as such.

3. Acoustic leakage marker (110) according to claim 1 or 2, wherein a frequency spectrum of the reference signal (200) has at least partially, in particular at least half, preferably mainly, frequencies below a frequency of 24 kHz, in particular below a frequency of 20 kHz, preferably below a frequency of 15 kHz.

4. Acoustic leakage marker (110) according to any one of claims 1 to 3, wherein the sound transfer structure (130) comprises a plunger (134) which is configured to make direct contact with the line (400) when the leakage marker (110) is mounted on the line.

5. Acoustic leakage marker (110) according to claim 4, wherein the plunger (134) has a bearing surface (136) and wherein the plunger (134) is configured, in a mounted state of the leakage marker (110), to contact the line (400) directly with the bearing surface (136), wherein the bearing surface (136) corresponds in particular to an area of ​​a predefined leak (410) of the line (400).

6. Acoustic leakage marker (110) according to claim 4 or 5, wherein the sound transfer structure (130) comprises a means (138) for exerting a force on the plunger (134); wherein the means (138) for exerting a force comprises in particular a spring and / or an elastic material, and / or wherein the force, in the mounted state of the leakage marker (110), is exerted in particular in the direction of the line (400).

7. Acoustic leakage marker (110) according to one of claims 1 to 6, wherein the sound transfer structure (130) comprises a membrane (142) which is arranged in direct contact with the plunger (134), in particular wherein the sound transmitter (140) is arranged at least partially on the membrane (142).

8. Acoustic leakage marker (110) according to one of claims 1 to 7, wherein the sound transmitter (140) comprises a piezoelectric element, a loudspeaker, a linear resonance actuator and / or a structure-borne sound transducer.

9. Acoustic leakage marker (110) according to claim 7, wherein the sound transmitter (140) comprises a piezoelectric element in direct contact with the plunger (134), and wherein KM / rc 241143WO 6 January 2026 the sound transmitter (140) further comprises a loudspeaker, a linear resonance actuator and / or a structure-borne sound transducer, which is at least partially arranged on the diaphragm (142).

10. Leakage detection system (100) comprising an acoustic leakage marker (110) according to any one of claims 1 to 9 and a measuring device (150) for recording the reference signal transmitted from the acoustic leakage marker (110) to the line (400).

11. Leakage detection system (100) according to claim 10, wherein the measuring device (150) is set up to be arranged in the line (400).

12. Method (600) for transmitting a reference signal (200) to a line (400) carrying a medium (500), wherein the method (600) comprises: Mounting (610) an acoustic leakage marker (110), in particular according to one of claims 1 to 9, with a sound transmitter (140) for generating a reference signal (200) and with a sound transfer structure (130) in contact with the sound transmitter, on the line (400), such that the sound transfer structure (130) is in direct contact with the line (400); and Generating (620) the reference signal (200) with the sound transmitter (140), so that the reference signal (200) is transferred from the sound transmitter (140) via the sound transfer structure (130) to the line (400).

13. Method according to claim 12, where one of the materials of the conduit (400) contains metal, plastic, asbestos and / or concrete; and / or wherein the medium (500) contains a gas or a liquid, in particular water. KM / rc 241143WO January 6, 202614. Use of the acoustic leakage marker (110) according to one of claims 1 to 9 to transmit a reference signal (200) to a line (400).

15. Use of the leak detection system (100) according to one of claims 10 or 11 to verify a function of the measuring device (150) using the reference signal (200) and / or to generate at least one reference value in a measurement of the measuring device (150) using the reference signal (200). KM / rc 241143WO January 6, 2026

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