Systems and Methods for Detecting a Leakage Flow of a Toilet

Abstract

A system for detecting a leakage flow of a toilet having a water cistern and an inlet pipe that is in fluid communication with the water cistern is disclosed. The system includes a vibration sensor arranged in a position, in which the vibration sensor can detect vibration signals caused by water flowing through the inlet pipe or through the water cistern and a computer unit arranged and configured to receive data from the vibration sensor. The computer unit is configured to determine when no vibration amplitude below a predefined amplitude level has been detected by the vibration sensor in a predefined time period.

Claims

1. A system for detecting a leakage flow of a toilet having a water cistern and an inlet pipe that is in fluid communication with the water cistern, the system comprising: a vibration sensor arranged in a position, in which the vibration sensor can detect vibration signals caused by water flowing through the inlet pipe or through the water cistern; and a computer unit arranged and configured to receive data from the vibration sensor; wherein the computer unit is configured to determine when no vibration amplitude below a predefined amplitude level has been detected by the vibration sensor in a predefined time period.

2. The system according to claim 1, wherein the vibration sensor comprises a communication module configured to transmit signals to an external receiver.

3. The system according to claim 1, wherein the vibration sensor comprises a satellite-based radio navigation unit.

4. The system according to claim 1, wherein the vibration sensor comprises a unique identification that is linked to the position of the toilet to which the vibration sensor is installed.

5. The system according to claim 1, wherein the predefined amplitude level corresponds to a flow of 5-1000 ml/min through the inlet pipe.

6. The system according to claim 1, wherein the predefined time period is within a range of 10-600 minutes.

7. The system according to claim 1, wherein the sensor comprises a setting unit by which the predefined time period and/or the predefined amplitude level can be set and/or changed.

8. The system according to claim 1, wherein the sensor comprises a setting unit by which a sampling rate of the sensor and/or a frequency with which the sensor sends signals can be set and/or changed.

9. The system according to claim 1, wherein the system comprises a plurality of vibration sensors each arranged to detect vibration signals caused by water flowing through the inlet pipe or through the water cistern of different toilets.

10. A method for detecting a leakage flow of a toilet having a water cistern and an inlet pipe in fluid communication with the water cistern, the method comprising: arranging a vibration sensor in a position, in which the vibration sensor can detect vibration signals caused by water flowing through the inlet pipe or through the water cistern; detecting vibration signals caused by water flowing through the inlet pipe or through the water cistern by the vibration sensor; determining when no vibration signals having a vibration amplitude below a predefined amplitude level have been detected by the vibration sensor in a predefined time period.

11. The method according to claim 10, further comprising generating an alert when no vibration signals having a vibration amplitude below the predefined amplitude level have been detected by the vibration sensor in the predefined time period.

12. The method according to claim 10, further comprising transmitting signals to an external receiver.

13. The method according to claim 10, wherein the vibration sensor applies satellite-based radio navigation to detect and send its position.

14. The method according to claim 10, wherein the vibration sensor comprises a unique identification that is linked to the position of the toilet to which the vibration sensor is installed and the unique identification is included in the signals.

15. The method according to claim 10, wherein the predefined amplitude level corresponds to a flow of 5-1000 ml/min through the inlet pipe.

16. The method according to claim 10, wherein the predefined time period is within a range of 10-600 minutes.

17. The method according to claim 10, further comprising setting and/or changing the predefined time period and/or the predefined amplitude level.

18. The method according to claim 10, further comprising setting and/or changing a sampling rate of the sensor and/or a frequency with which the sensor sends signals.

19. The method according to claim 10, further comprising applying a plurality of vibration sensors each arranged to detect vibration signals caused by water flowing through the inlet pipe or through the water cistern of different toilets, wherein the method for each toilet determines when no vibration signals having a vibration amplitude below the predefined amplitude level have been detected by the plurality of vibration sensor in the predefined time period.

Description

DESCRIPTION OF THE DRAWINGS

[0104] The invention will become more fully understood from the detailed description given herein below. The accompanying drawings are given by way of illustration only, and thus, they are not limitative of the present invention. In the accompanying drawings:

[0105] FIG. 1 shows a schematic view of a system according to the invention;

[0106] FIG. 2 shows a schematic view of another system according to the invention;

[0107] FIG. 3A shows a schematic view of a vibration sensor according to a system of the present invention before the sensor is attached to an inlet pipe of a toilet;

[0108] FIG. 3B shows another view of the vibration sensor shown in FIG. 3A;

[0109] FIG. 3C shows a view of the vibration sensor shown in FIG. 3A and FIG. 3B in a configuration in which the sensor has been attached to the inlet pipe;

[0110] FIG. 3D shows the vibration sensor shown in FIG. 3C in a configuration in which holding structures have been attached to the sensor to improve the attachment to the inlet pipe;

[0111] FIG. 4A shows a schematic, cross-sectional view of a vibration sensor according to a system of the present invention that is attached to an inlet pipe of a toilet by means of a first mounting element;

[0112] FIG. 4B shows a schematic, cross-sectional view of a vibration sensor according to a system of the present invention that is attached to an inlet pipe of a toilet by means of a second mounting element;

[0113] FIG. 4C shows a schematic, cross-sectional view of a vibration sensor according to a system of the present invention that is attached to an inlet pipe of a toilet by means of a third mounting element;

[0114] FIG. 5 shows a graph depicting the flow of water leaving a toilet as a function of time;

[0115] FIG. 6 shows a graph depicting the flow of water leaving a toilet as a function of time, wherein a system according to the invention is used to detect if there is a leakage flow;

[0116] FIG. 7 shows a first graph depicting vibration signals (caused by flow of water leaving a toilet) detected by a system according to the invention as a function of time;

[0117] FIG. 8 shows a second graph depicting vibration signals (caused by flow of water leaving a toilet) detected by a system according to the invention as a function of time;

[0118] FIG. 9 shows a first graph depicting vibration signals (caused by flow of water leaving a toilet) detected by a system according to the invention as a function of time;

[0119] FIG. 10 shows a second graph depicting vibration signals (caused by flow of water leaving a toilet) detected by a system according to the invention as a function of time;

[0120] FIG. 11 shows a flow chart illustrating the main principles of a method according to the invention;

[0121] FIG. 12A shows a plurality of sensors each being arranged to detect a leakage flow of a toilet;

[0122] FIG. 12B shows a map indicating the location of buildings in which one or more sensors are arranged to detect a leakage flow of one or more toilets;

[0123] FIG. 13A shows a schematic view of a system according to the invention; and

[0124] FIG. 13B shows a schematic view of another system according to the invention.

DETAILED DESCRIPTION

[0125] Referring now in detail to the drawings for the purpose of illustrating embodiments of the present invention, a system of the present invention is illustrated in FIG. 1.

[0126] FIG. 1 illustrates a schematic view of a system 20 according to the invention. The system 20 is for detecting a leakage flow of a toilet 4 having a water cistern 10 and an inlet pipe 6 that is in fluid communication with the water cistern 10. The system comprises a vibration sensor 2 that is mounted on an inlet pipe 6 of the toilet 4. The sensor 2 is attached to and mechanically connected to the outside of the inlet pipe 6 of the toilet 4.

[0127] The inlet pipe 6 is in fluid communication with the water cistern 10. Accordingly, the flow detected by the vibration sensor 2 corresponds to the flow of water leaving the water cistern 10 and thus the flow of water leaving the toilet 4. The vibration sensor 2 is arranged in a position, in which the vibration sensor 2 can detect vibration signals caused by water flowing through the inlet pipe 6 and/or through the water cistern 10.

[0128] The system 20 comprises a computer unit 24 arranged and configured to receive data from the vibration sensor 2. The computer unit 24 is provided as a unit that is separated from the vibration sensor 2. The vibration sensor 2 is, however, communicatively connected to the computer unit 24. In an alternative embodiment, the computer unit 24 is integrated in the vibration sensor 2.

[0129] The vibration sensor 2 comprises a communication module 44 configured to transmit wireless signals 18. In an embodiment, the communication module comprises a radio-frequency module that is configured to transmit and optionally receive radio signals 18. The vibration sensor 2 comprises a satellite-based radio navigation unit 46. The vibration sensor 2 comprises a setting unit 48 that is used to set and/or change the predefined time period (ΔT) and/or the predefined amplitude level. The setting unit 48 can also be used to set and/or change the sampling rate of the vibration sensor 2 and/or the frequency with which the vibration sensor 2 sends signals 18.

[0130] In an embodiment, the communication module 44 is a long-range communication module 44 configured to apply a spread spectrum modulation technique derived from chirp spread spectrum technology.

[0131] The computer unit 24 is configured to determine when no vibration amplitude below a predefined amplitude level has been detected by the vibration sensor 2 in a predefined time period. The predefined time period may, by way of example, be 4 hours. By selecting a long, predefined time period, the risk for generating a false alert is reduced. However, by selecting a short, predefined time period, the likelihood for generating an alert is increased. In practice, one has to consider the activity of a toilet to set the optimal predefined time period. In principle, the value of the predefined time period should depend on the expected degree of usage of the toilet.

[0132] In an embodiment, the system applies a predefined time period that depends on the time of day. Accordingly, there is a diurnal variation with respect to the predefined time period. In an embodiment, the predefined time period has a first value during the opening hours of a building and a second predefined time period value during the remaining hours (the closing hours of a building).

[0133] The signals 18 sent by the sensor 2 are sent via the Internet 16. Since the computer unit 24 is connected to the Internet 16, the signals 18 are received by the computer unit 24 via a connection to the Internet 16.

[0134] In an alternative embodiment, the computer unit 24 is configured to directly receive the signals 18 transmitted by the sensor 2.

[0135] The inlet pipe 6 is in fluid communication with a water supply pipe 14. The water supply pipe 14 is connected to a connection structure, to which the inlet pipe 6 is connected. The water supply pipe 14 extends along a wall 12. The inlet pipe 6 and the water supply pipe 14 are provided on different sides of the wall 12.

[0136] FIG. 2 illustrates a schematic view of a system 20 according to the invention. The system 20 basically corresponds to the one shown in and explained with reference to FIG. 1. The sensor 2, however, is mounted on the water supply pipe 14 and not on the inlet pipe 6 as in FIG. 1.

[0137] It is possible to attach the sensor 2 in any position, in which the vibration sensor 2 can detect vibration signals caused by water flowing through the inlet pipe 6 or through the water cistern 10. In an embodiment, the sensor 2 is attached to the water cistern 10. In an embodiment, the sensor 2 is attached to another part of the toilet 4.

[0138] FIG. 3A illustrates a schematic view of a vibration sensor 2 according to a system of the present invention before the vibration sensor 2 is attached to an inlet pipe 6 of a toilet. The vibration sensor 2 comprises a housing having a contact surface that is provided with an adhesive layer 26. A protective foil 28 is attached to the outside surface of the adhesive layer 26 in order to protect the adhesive layer 26. Before the vibration sensor 2 is attached to a structure such as the inlet pipe 6 illustrated in FIG. 3A, the protective foil 28 is peeled off. In an embodiment, the contact surface of the housing has a geometry that matches the outside geometry of the structure (e.g. the inlet pipe 6), to which the vibration sensor 2 is intended to be attached.

[0139] FIG. 3B illustrates another view of the vibration sensor 2 shown in FIG. 3A. In this configuration, the protective foil 28 (shown in FIG. 3A) has been peeled off. Accordingly, the adhesive layer 26 is ready to be attached to the inlet pipe 6 in order to attach the vibration sensor 2 to the inlet pipe 6.

[0140] FIG. 3C illustrates a view of the sensor shown in FIG. 3A and FIG. 3B in a configuration, in which the vibration sensor 2 has been attached to the inlet pipe 6. The adhesive layer 26 has now been brought into contact with the outside portion of the inlet pipe 6.

[0141] FIG. 3D illustrates the vibration sensor 2 shown in FIG. 3C in a configuration, in which holding structures 8 have been attached to the vibration sensor 2 to improve the attachment of the vibration sensor 2 to the inlet pipe 6. In an embodiment, the holding structures 8 are shaped as cable ties. In an embodiment, the holding structures 8 are shaped as elastic bands or straps. In an embodiment, a single holding structure 8 is used.

[0142] In an embodiment, several holding structures 8 are used to secure the vibration sensor 2 to the inlet pipe 6 (or alternatively another structure such as a water cistern of a toilet or a water supply pipe that is in fluid communication with the inlet pipe 6 or the water cistern of a toilet).

[0143] FIG. 4A illustrates a schematic, cross-sectional view of a vibration sensor 2 according to a system of the present invention that is attached to an inlet pipe 6 of a toilet by means of a first mounting element 32. The first mounting element 32 comprises an attachment structure 34 that is shaped to receive and maintain the housing of the vibration sensor 2. The attachment structure 34 is basically box-shaped and comprises an opening provided in the distal end of the attachment structure 34. Hereby, the vibration sensor 2 can be inserted into the attachment structure 34 through the opening.

[0144] The attachment structure 34 comprises a closing plate provided in the proximal end of the attachment structure 34. The mounting element 32 comprises a clamping member 36 attached to and protruding from the closing plate of the attachment structure 34. The clamping member 36 is shaped to be attached to a cylindrical structure such as the inlet pipe 6. The clamping member 36 comprises mounting arms arranged and configured to bear against a cylindrical portion and hereby fix the mounting element 32 to the cylindrical portion.

[0145] In an embodiment, the clamping member 36 is designed to detachably attach the mounting element 32 to a cylindrical structure such as the inlet pipe 6.

[0146] FIG. 4B illustrates a schematic, cross-sectional view of a vibration sensor 2 according to a system of the present invention that is attached to an inlet pipe 6 of a toilet by a second mounting element 32.

[0147] The second mounting element 32 comprises an attachment structure 34 that is shaped to be attached to the housing of the vibration sensor 2. The attachment structure 34 comprises an end plate corresponding to the closing plate of the attachment structure 34 shown in FIG. 4A.

[0148] The mounting element 32 is provided with a clamping member 36 corresponding to the one that is shown in and explained with reference to FIG. 4B.

[0149] FIG. 4C illustrates a schematic, cross-sectional view of a vibration sensor 2 according to a system of the present invention that is attached to an inlet pipe 6 of a toilet by a third mounting element 32.

[0150] The third mounting element 32 corresponds to the one shown in and explained with reference to FIG. 4A. The third mounting element 32, however, comprises two additional structures: a support structure 35 shaped as a plate that abuts the distal end of the housing of the vibration sensor 2 and an elastic strap 37 comprising a fixation structure 41 for attaching to the ends of the elastic strap 37 to each other. When the elastic strap 37 is mounted, the elastic strap 37 presses the third mounting element 32 towards the inlet pipe 6. Moreover, the elastic strap 37 presses the support structure 35 towards the housing of the vibration sensor 2 and hereby prevents the vibration sensor 2 from falling out of the third mounting element 32.

[0151] FIG. 5 illustrates a graph depicting the flow Q of water leaving a toilet as a function of time T. It can be seen that the flow Q of water is zero in some time periods and that the flow Q of water is non-zero in the remaining time periods. The periods in which the flow is non-zero represents the time periods after flushing the toilet.

[0152] Since the toilet has two levels of flushing, some of the non-zero flows of water correspond to a first flow value Q.sub.1, while the remaining non-zero flows of water correspond to a second higher flow value Q.sub.2.

[0153] FIG. 6 illustrates a graph depicting the flow Q of water leaving a toilet as a function of time, wherein a system according to the invention is used to detect if there is a leakage flow. The system detects the flow of water leaving the toilet several times from a first point in time T.sub.1 to a later point in time T.sub.N. During this predefined time period ΔT, no flow measurement is below the predefined flow level Q.sub.L (indicated by a dotted line). Accordingly, the system according to the invention generates an alert. On the other hand, if one or more of the flow measurements had been below the predefined flow level Q.sub.L, the system would not have generated an alert.

[0154] When looking at the graph shown in FIG. 6 one can see that a non-zero leakage flow 22 is present between the time periods, in which a first non-zero flow value Q.sub.1 or a second higher non-zero flow value Q.sub.2 is present. If there was no leakage flow 22, one would expect the flow Q to fall below the predefined flow level QL.

[0155] FIG. 7 illustrates a first graph depicting the amplitude of vibration signals caused by flow of water leaving a toilet as a function of time. These vibration signals are detected by means of a system according to the invention. The system according to the invention integrates the amplitudes of vibration signals in a number of time periods of equal duration. The duration may be selected in any manner that provides useable measurements. In an embodiment, the duration is 10 minutes. In an embodiment, the duration is 8 minutes. In an embodiment, the duration is 5 minutes. In an embodiment, the duration is 4 minutes. In an embodiment, the duration is 2 minutes.

[0156] In an embodiment, the duration is 1 minute. In an embodiment, the duration is 45 seconds. In an embodiment, the duration is 30 seconds. In an embodiment, the duration is 20 seconds. In an embodiment, the duration is 15 seconds. In an embodiment, the duration is 10 seconds. In an embodiment, the duration is 8 seconds. In an embodiment, the duration is 5 seconds. In an embodiment, the duration is 3 seconds. In an embodiment, the duration is 2 seconds. In an embodiment, the duration is 1 second. In an embodiment, the duration is 0.5 seconds. In an embodiment, the duration is 0.2 second. In an embodiment, the duration is 0.1 seconds.

[0157] Below the graph a table is shown. The table shows the amplitude A (integrated values) for a plurality of time periods T.sub.0, T.sub.1, T.sub.2, T.sub.3, T.sub.N-1, T.sub.N, T.sub.N+1 indicated in the graph.

[0158] During a first measurement period T.sub.0, a non-zero local peak vibration signal 31 is detected. The integrated value for the first measurement period T.sub.0 is 682.

[0159] The sensor may deliver the measurements as electrical values. These values may be amplified and filtered if desired.

[0160] During a next measurement period T.sub.1, a significantly lower non-zero vibration signal 31′ is detected. The integrated value for this measurement period T.sub.1is 144.

[0161] During a next measurement period T.sub.2, a non-zero vibration signal 31″ is detected. The integrated value for this measurement period T.sub.2 is 1528.

[0162] During a next measurement period T.sub.3, a non-zero vibration signal 31‴ is detected. The integrated value for this measurement period T.sub.3 is 1546.

[0163] During a next measurement period T.sub.N-1, a non-zero vibration signal 33 is detected. The integrated value for this measurement period T.sub.N-1 is 664.

[0164] During a next measurement period T.sub.N, a non-zero vibration signal 33′ is detected. The integrated value for this measurement period T.sub.N is 128.

[0165] During a next measurement period T.sub.N+1, a non-zero vibration signal 33″ is detected. The integrated value for this measurement period T.sub.N+1is 1488.

[0166] On the basis of these measurements, the system according to the invention performs a test to determine if there is a leakage flow. The test comprises the step of determining whether or not a vibration amplitude A below a predefined amplitude level A.sub.L (indicated by a dotted line) has been detected by the vibration sensor of the system during the predefined time period ΔT.

[0167] Since the amplitude A has been below the predefined amplitude level A.sub.L during the predefined time period ΔT, the system determines that there is no leakage flow.

[0168] FIG. 8 illustrates a second graph depicting the amplitude of vibration signals caused by flow of water leaving a toilet as a function of time. These vibration signals are detected by means of a system according to the invention. The system according to the invention integrates the amplitude of vibration signals in a number of time periods of equal duration.

[0169] Below the graph a table is shown. The table shows the amplitude A (integrated values) for a plurality of time periods T.sub.0, T.sub.1, T.sub.2, T.sub.3, T.sub.N-1, T.sub.N, T.sub.N+1 indicated in the graph.

[0170] During a first measurement period T.sub.0, a non-zero local peak vibration signal 31 is detected. The integrated value for the first measurement period T.sub.0 is 684.

[0171] During a next measurement period T.sub.1, a significantly lower non-zero vibration signal 31′ is detected. The integrated value for this measurement period T.sub.1 is 148.

[0172] During a next measurement period T.sub.2, a non-zero vibration signal 31″ is detected. The integrated value for this measurement period T.sub.2 is 150.

[0173] During a next measurement period T.sub.3, a non-zero vibration signal 31‴ is detected. The integrated value for this measurement period T.sub.3 is 162.

[0174] During a next measurement period T.sub.N-1, a non-zero vibration signal 33 is detected. The integrated value for this measurement period T.sub.N-1 is 156.

[0175] During a next measurement period T.sub.N, a non-zero vibration signal 33′ is detected. The integrated value for this measurement period T.sub.N is 154.

[0176] During a next measurement period T.sub.N+1, a non-zero vibration signal 33″ is detected. The integrated value for this measurement period T.sub.N+1is 160.

[0177] On the basis of these measurements, the system according to the invention performs a test to determine if there is a leakage flow by determining whether or not a vibration amplitude A below a predefined amplitude level A.sub.L (indicated by a dotted line) has been detected by the vibration sensor of the system during the predefined time period ΔT.

[0178] Since the amplitude A has not been below the predefined amplitude level A.sub.L during the predefined time period ΔT, the system determines that there is a leakage flow.

[0179] FIG. 9 illustrates a first graph depicting vibration signals 30, 30′ (caused by flow of water leaving a toilet) detected by a system according to the invention as a function of time. Instead of integrating measurement values of several time periods, only a single measurement is performed for the flowing times T.sub.0, T.sub.1, T.sub.2, T.sub.3, T.sub.N-1, T.sub.N as indicated in the graph.

[0180] Since some of the vibration signals (e.g. the one at time T.sub.1 and T.sub.N) have a value below the predefined amplitude level A.sub.L during the predefined time period ΔT, the system determines that there is no leakage flow.

[0181] FIG. 10 illustrates a second graph depicting vibration signals 30, 30′ (caused by flow of water leaving a toilet) detected by a system according to the invention as a function of time. A single measurement is performed for the flowing times T0, T.sub.1, T2, T3, TN-1, T.sub.N as indicated in the graph.

[0182] Since none of the vibration signals 30, 30′ has a value below the predefined amplitude level A.sub.L during the predefined time period ΔT, the system determines that there is a leakage flow 22.

[0183] FIG. 11 illustrates a flow chart illustrating the main principles of a method according to the invention.

[0184] In the first step I, a vibration sensor 2 is installed and activated. In an embodiment, the vibration sensor 2 is attached to an inlet pipe that is in fluid communication with a water cistern of a toilet. In an embodiment, the vibration sensor 2 is attached to a supply pipe that is in fluid communication with an inlet pipe that is in fluid communication with a water cistern of the toilet. In an embodiment, the vibration sensor 2 is attached to a water cistern of the toilet.

[0185] It is important to note that a vibration sensor 2 may be installed on several toilets in one or more buildings.

[0186] When the one or more vibration sensors 2 are installed, the one or more vibration sensors 2 are activated so that they perform vibration measurements with a predefined frequency (sampling rate).

[0187] In the second step, II, vibration signals 30, 30′ and their amplitude A are detected by the at least one sensor 2. The measurements may be conducted in several ways.

[0188] In an embodiment, the measurements are conducted on a continuous basis and the data are sent to a computer unit (e.g. a processor) for further processing.

[0189] In an embodiment, the data are stored temporarily. In this embodiment, the data sent to the computer unit represents a plurality of measurements.

[0190] In an embodiment, the data are integrated and stored as an integrated value representing a time period, during which several measurements have been carried out. In this embodiment, data integrated during the time period are sent to the computer unit as integrated data.

[0191] In the third step, III, it is determined whether or not the amplitudes 31, 31′, 31″, 31‴, 33, 33′, 33″ of the vibration signals are below a predefined amplitude level A.sub.L during a predefined time period ΔT.

[0192] If, during the third step, III, it is determined that at least one of the amplitudes 31, 31′, 31″, 31‴, 33, 33′, 33″ of the vibration signals is below a predefined amplitude level A.sub.L during a predefined time period ΔT, step II is repeated.

[0193] If, on the other hand, during the third step, III, it is determined that none of the amplitudes 31, 31′, 31″, 31‴, 33, 33′, 33″ of the vibration signals are below a predefined amplitude level A.sub.L during a predefined time period ΔT, an alert is generated as shown in step IV. After this, step II is repeated.

[0194] The generation of an alert may include one or more notifications being sent to one or more individuals. In an embodiment, the position of the toilet that has a leakage flow is included in the alert. This can be done if the signals sent from the sensor 2 include information that can be used to determine the location of the toilet. In an embodiment, the positions of all sensors 2 are listed in a database, wherein a unique identification is assigned to each sensor 2. Accordingly, the position/location of each sensor 2 can be established by the unique identification. Accordingly, service staff can be informed so that the leakage flow can be stopped, e.g. by repairing the toilet or replacing the toilet with a new toilet.

[0195] FIG. 12A illustrates a plurality of sensors 2 each being arranged to detect a leakage flow of a toilet. All sensors 2 comprise a communication module allowing the sensor 2 to send wireless signals 18 including the measurements made by the sensor 2 as well as a position or a unique identification that can be used to determine the position of the toilet (e.g. by using a predefined database, in which the positions of all toilets are saved together with a unique identification).

[0196] The sensors 2 send wireless signals 18 to an office 42 or alternatively a server that is accessible from the office 42. Hereby, it is possible to monitor all sensors 2 from the office 42. If an alert is generated, this will be communicated to the office 42. Accordingly, any predefined action can be initiated.

[0197] FIG. 12B illustrates a map 38 indicating the location 40, 40′, 40″ of buildings, in which one or more sensors are arranged to detect a leakage flow of one or more toilets.

[0198] A system according to the invention can be used to monitor an area of a state, an entire city or an area of a city.

[0199] FIG. 13B illustrates a schematic view of a system 20 according to the invention. The system 20 basically corresponds to the one shown in and explained with reference to FIG. 1. The sensor 2, however, is mounted on the water cistern 10 and not on the inlet pipe 6 as in FIG. 1.

[0200] It is possible to attach the sensor 2 in any position on the water cistern 10 provided that the vibration sensor 2 can detect vibration signals caused by water flowing through the inlet pipe 6 or through the water cistern 10.

[0201] FIG. 13A illustrates a schematic view of a system 20 according to the invention. The system 20 basically corresponds to the one shown in and explained with reference to FIG. 13B. The sensor 2, however, is mounted on the outside of the toilet bowl.

[0202] It is possible to attach the sensor 2 in any position on the toilet bowl provided that the vibration sensor 2 can detect vibration signals caused by water flowing through the inlet pipe 6 or through the water cistern 10.

TABLE-US-00001 List of reference numerals 2 Sensor 4 Toilet 6 Inlet pipe 8 Holding structure 10 Water cistern 12 Wall 14 Water supply pipe 16 Internet 18 Wireless signal 20 System 22 Leakage flow 24 Computer unit 25 Amplitude 26 Adhesive layer 28 Protective foil 30, 30′ Vibration signal 31, 31′, 31″, 31‴ Vibration signal 33, 33′ Vibration signal 32 Mounting element 34 Attachment structure 35 Support structure 36 Clamping member 37 Elastic strap 38 Map 40, 40′, 40″ Building 41 Fixation structure 42 Office 44 Communication module 46 Satellite-based radio navigation unit 48 Setting unit T.sub.0, T.sub.1, T.sub.2, T.sub.3 Time T.sub.N-1, T.sub.N, T.sub.N+1 Time T Time ΔT Time period Q, Q.sub.1, Q.sub.2 Flow QL Flow level A Amplitude AL Amplitude level I,II,III,IV Step