METHOD FOR DETECTING A LEAK IN A LIQUID PIPE AND WATER METER WITH A CONTROL UNIT FOR EXECUTING THE METHOD

Description

[0001] The present invention relates to a method for detecting a leak in a fluid line and to a water meter with a controller for implementing the method according to the preamble of patent claim 1. Such a method is described in WO2014 / 203246A1. The invention serves in particular to prevent water damage caused by escaping fluids.

[0002] Buildings typically contain numerous water pipes that lead from a fluid source, such as a public water supply network, to various consumers, such as plumbing fixtures, dishwashers, or washing machines. Leaks can occur in these fluid lines, for example, in the form of pipe bursts or cracks through which fluid can escape. The leaking fluid can cause significant damage to the building, masonry, and / or building facilities at the points of leakage.

[0003] Leaks with large amounts of fluid, such as those that occur in pipe bursts, can be detected using flow sensors, for example. Such flow sensors require a very wide measuring range of up to 100 l / min (liters per minute). As a result, the flow sensors are not suitable for detecting small amounts of fluid, especially less than 0.8 l / min, such as those that occur in drip leaks. Such drip leaks can therefore remain undetected for a long time, meaning the escaping fluid can cause considerable damage, for example, through mold growth.

[0004] In addition, threshold values ​​for the fluid flow rate can be monitored, above which a pipe burst is assumed. To avoid false alarms, these threshold values ​​must be set relatively high. Therefore, these methods cannot detect leaks involving smaller fluid volumes than those resulting from a pipe burst.

[0005] Furthermore, it is difficult to distinguish leaks from fluid consumption that typically occurs in supply units, such as an apartment, a hotel room or a building.

[0006] The object of the invention is therefore to at least partially solve the problems described with reference to the prior art and, in particular, to provide a method for detecting a leak in a liquid line with which leaks can be detected with greater reliability. Furthermore, a water meter is to be provided with which leaks can be detected with greater reliability.

[0007] These objects are achieved by a method and a water meter according to the features of the independent patent claims. Further advantageous embodiments of the invention are specified in the dependent patent claims. It should be noted that the features listed individually in the dependent patent claims can be combined with one another in any technologically expedient manner and define further embodiments of the invention. Furthermore, the features listed in the patent claims are further specified and explained in the description, with further preferred embodiments of the invention being presented.

[0008] A method for detecting a leak contributes to this, which comprises at least the following steps: a) detecting a flow rate of a liquid through a line during a plurality of liquid withdrawal processes; b) comparing the flow rates of the liquid of the respective liquid withdrawal processes with an alarm value; c) issuing an alarm signal if the flow rate of the liquid of a liquid withdrawal process exceeds the alarm value; d) adjusting the alarm value depending on an (absolute or relative) frequency of occurrence of the flow rates of the liquid of the liquid withdrawal processes above an adjustment value.

[0009] The method is used to detect a leak in a fluid line, which in particular runs at least partially within a building from a fluid source, such as a public water supply network, to at least one consumer, such as a sanitary fixture, a dishwasher, or a washing machine. The fluid line is in particular made at least partially of metal, such as copper. The fluid line or piping also has a diameter of 10 mm (millimeters) to 30 mm.

[0010] To detect a leak in the fluid line, in step a), a flow rate of a fluid through a line is recorded during a plurality of fluid withdrawal processes. A fluid withdrawal process can, for example, occur through a consumption process of the fluid, such as withdrawing the fluid from a plumbing fixture, using a washing machine, using a toilet, and / or using a shower. An individual fluid withdrawal process can be considered "started" when the flow rate of the fluid through the fluid line increases from 0 l / min (liters per minute) to a positive value. An individual fluid withdrawal process can be considered "finished" when the flow rate of the fluid through the fluid line decreases back to 0 l / min.Therefore, if several consumption processes overlap in time, they are considered a single fluid withdrawal process. For each fluid withdrawal process, the flow rate of the fluid through the fluid line is recorded, i.e., the amount of fluid flowing through the fluid line during a fluid withdrawal process.

[0011] For this purpose, in particular, a duration of the liquid withdrawal process or a flow duration of the liquid through the liquid line per liquid withdrawal process and the (in particular average) flow rate of the liquid through the liquid line during the liquid withdrawal process can be recorded. The flow rate, the duration of the liquid withdrawal process, the flow duration of the liquid through the liquid line per liquid withdrawal process and / or the (in particular average) flow rate of the liquid through the liquid line during the liquid withdrawal process can be stored as a data set for each liquid withdrawal process, for example in an (electronic) storage device. Flow sensors and / or time measuring devices, for example, can be used to record these values.

[0012] Each liquid withdrawal process can be represented as a point in a (scatter) diagram or consumption field. The diagram is spanned by an x-axis and a y-axis that are perpendicular to each other. The x-axis shows in particular the duration of the liquid withdrawal process or the flow time of the liquid through the liquid line per liquid withdrawal process, for example in minutes, and the y-axis shows the (in particular average) flow rate of the liquid through the liquid line during the liquid withdrawal process in l / min. The position of the point of the respective liquid withdrawal process in the diagram is thus determined by the (in particular average) flow rate of the liquid through the liquid line and the duration of the liquid withdrawal process or the flow time of the liquid through the liquid line of the respective liquid withdrawal process.This allows each liquid withdrawal process to be saved as an event in the diagram or consumption field.

[0013] Then or subsequently, in step b), the flow rates of the liquid of the respective liquid withdrawal processes are compared with an alarm value. The alarm value is in particular a threshold value above which an abnormally or unexpectedly high consumption value is assumed for the monitored supply unit. The alarm value can be displayed in the diagram, for example, as a graph and / or line. The comparison between the flow rates of the liquid of the respective liquid withdrawal processes and the alarm value can thus (also) be made by comparing the relative position of the point of the respective liquid withdrawal process to the graph or the line of the alarm value. If the point of a liquid withdrawal process is located, for example, to the right of the graph or the line of the alarm value, the flow rate of the liquid of the liquid withdrawal process exceeds the alarm value.For example, if the point of the liquid withdrawal process is to the left of the graph and / or the line of the alarm value, the flow rate of the liquid of the liquid withdrawal process is below the alarm value.

[0014] If the flow rate of the liquid during a liquid withdrawal process exceeds the alarm value, an alarm signal is issued in step c). The alarm signal can, for example, be a message to a resident of the supply unit, a monitoring system, a control unit and / or an actuator of the liquid line. The message can, for example, be sent in the form of an electronic message to the resident's mobile phone. The alarm signal can also be an acoustic and / or visual alarm signal, which signals to the resident that unusual (particularly unexpectedly high) liquid consumption is being used. The resident can then, for example, manually close a valve used to close the liquid line in order to prevent the liquid from escaping from a possible leak.Furthermore, the valve can optionally also be closed automatically via a control signal. The valve can, for example, be a solenoid valve that can be actuated by a control system (automatic and / or electrically).

[0015] In step d), the alarm value is adjusted depending on the (absolute or relative) frequency of the liquid flow rates of the liquid withdrawal processes occurring above an adjustment value. This means that it is first determined how often the liquid flow rates of the individual liquid withdrawal processes are above the (specifiable) adjustment value. If the frequency reaches a (specifiable) frequency value within a (specifiable) period of time (e.g. 6 hours), for example (e.g. 50% of the liquid flow rates of the individual liquid withdrawal processes above the (specifiable) adjustment value), the alarm value can be increased by a (specifiable) value and / or factor (e.g. 10%). This can mean that the graph or line of the alarm value is shifted to the right in the diagram.If the frequency within the (specifiable) time period (e.g., 6 hours) does not reach the (specifiable) frequency value, or if this value is even "0" (i.e., none of the liquid flow rates of the individual liquid withdrawal processes are above the (specifiable) adjustment value), the alarm value can be reduced by a (specifiable) value or factor (e.g., 10%). This can mean that the graph or line of the alarm value is shifted to the left in the diagram. The adjustment value can therefore be a threshold value; if exceeded, the alarm value is adjusted with the (specifiable) frequency. In particular, the adjustment can only be carried out if a minimum number of liquid withdrawal processes have occurred, for example, at least 10 liquid withdrawal processes.Furthermore, the adjustment can take place, for example, four times a day (for example at 00:00, 06:00, 12:00 and 18:00). Furthermore, it can be provided that the adjustment value is never reduced below a (specifiable) minimum adjustment value and / or never increased above a (specifiable) maximum adjustment value. The adjustment value can also be represented in the diagram, for example, as a graph and / or line. If the point of a liquid withdrawal process is located, for example, to the right of the graph or the line of the adjustment value, the flow rate of the liquid of the liquid withdrawal process exceeds the adjustment value. If the point of the liquid withdrawal process is located, for example, to the left of the graph or the line of the adjustment value, the flow rate of the liquid of the liquid withdrawal process falls below the adjustment value. In particular, the adjustment value is lower than the alarm value.This also means, among other things, that the graph or line of the adjustment value is located to the left of the graph or line of the alarm value in the diagram. Step d) thus adjusts the alarm value to the typical flow rates of the liquid through the liquid line during a liquid withdrawal process in the consumption unit, allowing leaks to be detected with greater reliability.

[0016] As already explained above, in step a), an (average) flow rate of the liquid and a flow duration of the liquid can be recorded for each liquid withdrawal event. The (average) flow rate of the liquid and the flow duration of the liquid per liquid withdrawal event can be recorded (for each event) in a (scatter) diagram.

[0017] When adjusting the alarm value in step d), the adjustment value can be adjusted depending on the alarm value. This means, in particular, that the adjustment value is (also) increased or decreased when the alarm value is increased or decreased. For example, the adjustment value can be adjusted by the same amount or by the same factor as the alarm factor. Furthermore, this can mean that the graph or line of the adjustment value in the diagram is shifted in the same direction as the graph or line of the alarm value and / or parallel to the graph or line of the alarm value.

[0018] At least the adjustment value or the alarm value can be separately adjustable for a plurality of fluid flow velocity ranges. For this purpose, a plurality of fluid flow velocity ranges, such as a low range, a medium range, and a high range, can be defined for which the adjustment value and / or the alarm value can be separately or individually adjusted.

[0019] The detection of leaks includes measuring the pressure of the liquid in the line. By measuring the pressure of the liquid in the line, for example, micro leaks with flow rates of the liquid through the liquid line of, for example, less than 0.8 l / min, preferably 0.05 l / min to 0.8 l / min and / or drip leaks with flow rates of the liquid through the liquid line of, for example, less than 0.2 l / h (liters per hour) can be detected. The flow rates of such micro leaks and drip leaks may not be detectable by flow sensors already installed. The detection of drip leaks can in particular take place once a day, for example at a time when the flow rate of the liquid in the liquid line is regularly or usually 0 l / min.Furthermore, a pressure chamber can be created in the fluid line for pressure measurement by closing the valve, which could be a main water valve, for example. The valve can be closed for 30 seconds, for example. If a consumption process is triggered during the measurement, this is indicated by a very sharp pressure drop in the pressure chamber. In this case, the valve can be opened immediately and the measurement aborted. If a (slight) pressure drop (e.g., more than 500 mbar (millibars)) is detected in the pressure chamber of the fluid line during two consecutive measurements, this indicates a drip leak.To detect a microleak, the fluid pressure in the fluid line can be measured several times a day, for example, ten times a day. A measured pressure drop during several consecutive measurements, for example, three measurements, indicates an unusually constant flow of small amounts of fluid through the fluid line and thus a leak. In both cases, an alarm signal can also be issued according to step c).

[0020] It can be provided that the leak detection comprises a measurement of the flow rate of the liquid through the liquid line, and wherein an alarm signal is issued when the flow rate of the liquid exceeds a first threshold value. The first threshold value can be, for example, 20 l / min to 100 l / min, preferably 50 l / min. If the measured flow rate of the liquid through the liquid line is above this (very high) first threshold value, this indicates a pipe burst. In this case, the valve can be closed automatically and / or an alarm signal can be issued according to step c).

[0021] An alarm signal can be issued if the flow rate exceeds a second threshold in step a). In particular, an alarm signal is issued if the flow rate of a single liquid withdrawal process exceeds the second threshold in step a. The second threshold can be, for example, 100 liters to 2,000 liters, preferably 300 liters.

[0022] At least the first threshold or the second threshold can be adjustable. This means, in particular, that the first threshold and / or the second threshold can be adjusted for different consumption units.

[0023] According to a further aspect, a water meter is also provided with a valve, a flow sensor for a liquid and a pressure sensor for a liquid, which are connected to a controller in a data-conducting manner, wherein the controller is configured to carry out a method explained here.

[0024] The water meter can be used to determine, in particular, water consumption in a consumption unit, such as a building, an apartment, or a hotel room, so that a liquid, in particular water, can be billed based on consumption. The water meter is arranged, in particular, in a liquid line through which the liquid can be conducted from a liquid source to at least one consumer. Furthermore, the water meter has a valve with which the liquid line can be closed, a flow sensor with which a liquid flow through the liquid line can be determined, and a pressure sensor with which a pressure or pressure curve in the liquid line can be determined. These sensors are connected to a controller in a data-conducting manner (via cable connection and / or radio connection). The controller is, in particular, a microcontroller.The controller is configured and intended to carry out the method according to the invention. For further details, please refer to the description of the method according to the invention.

[0025] The invention and the technical environment are explained in more detail below with reference to the figures. It should be noted that the figures show particularly preferred embodiments of the invention, but the invention is not limited thereto. Identical elements in the figures are provided with the same reference numerals. They show, by way of example and schematically: Fig. 1: a representation of a flow velocity curve of a liquid through a liquid line; Fig. 2: a (scatter) diagram; Fig. 3: the (scatter) diagram with a first adjustment of the alarm value and the adjustment value; Fig. 4: the (scatter) diagram with a second adjustment of the alarm value and the adjustment value; Fig. 5: the (scatter) diagram with a third adjustment of the alarm value and the adjustment value; Fig. 6: the (scatter) diagram with a fourth adjustment of the alarm value and the adjustment value; and Fig. 7: a building with a water meter.

[0026] The Fig. 1 shows a representation of a recorded course of a flow velocity of a liquid through a (in the Fig. 7shown) liquid line 8. The graph 27 represents the flow rate of the liquid through the liquid line 8 in l / min over a certain period of time. Four liquid withdrawal processes 1.1, 1.2, 1.3 and 1.4 (each as a separate event) can be seen, each of which has different durations and different flow rate profiles.

[0027] The four liquid extraction processes 1.1, 1.2, 1.3 and 1.4 are in the Fig. 2shown as points in a diagram 4. The diagram 4 has an x-axis 28, on which the duration in minutes, and a y-axis 29, on which the flow rate is plotted in l / min. The positions of the liquid withdrawal processes 1.1, 1.2, 1.3 and 1.4 in the diagram 4 thus result from the duration and the (average) flow rate of the liquids in the respective liquid withdrawal processes 1.1, 1.2, 1.3 and 1.4. The flow rate of the liquids on the y-axis is divided into a first area 21, for example a drip leakage area, a second area 22, for example a microleakage area, a third area 23, for example for medium flow rates, and a fourth area 24, for example for high flow rates.The first range 21 extends, for example, from 0 l / min to 0.00333 l / min (0.2 l / h), the second range 22 from 0.00333 l / min (0.2 l / h) to 0.8 l / min, the third range 23 from 0.8 l / min to 50 l / min, and the fourth range 24 from 50 l / min to infinity. The third range 23 is in turn divided into a lower range 5, a middle range 6, and a high range 7. The lower range 5, the middle range 6, and the high range 7 can be evenly distributed over the third range 23. Furthermore, the lower range 5 can form approximately 40% of the third range 23, the middle range 6 approximately 40% of the third range 23, and the high range 7 approximately 20% of the third range 23. In addition, the lower range 5 can extend from 0.8 l / min to 20 l / min, the middle range 6 from 20 l / min to 40 l / min and the high range 7 from 40 l / min to 50 l / min.Diagram 4 also shows a first line 16 for an alarm value 2, a second line 17 for an adjustment value 3, a horizontal third line 18 for a first threshold value 9 of the flow rate, and a fourth line 19 for a second threshold value 10 for a flow rate of the liquid through the liquid line 8. It can be seen that the liquid extraction processes 1.1 and 1.3 are located to the left of the first line 16 for the alarm value 2 and to the left of the second line 17 for the adjustment value 3. This means that the flow rates and flow rates of the liquid within the liquid extraction processes 1.1 and 1.3 are below the alarm value 2 and the adjustment value 3. The liquid extraction process 1.4 is located to the right of the first line 16 for the alarm value 2.This means that the flow rate and flow velocity of the liquid within the liquid withdrawal process 1.4 exceeds the alarm value 2, so that an alarm signal is issued according to step c). Furthermore, it can be seen that the liquid withdrawal processes 1.2 and 1.4 are located to the right of the second line 17 of the adjustment value 3. This means that the flow rates and flow velocity of the liquid within the liquid withdrawal processes 1.2 and 1.4 are above the adjustment value 3. In step d), the frequency, for example in the form of a (relative or absolute) number, of the liquid withdrawal processes located to the right of the second line 17 of the adjustment value 3 is determined.If the frequency exceeds a predeterminable frequency value within a predeterminable period of time and / or after recording a predeterminable number of recorded fluid withdrawal processes, an adjustment of the alarm value 2 takes place in step d) in the form of a shift of the first line 16 to the right and / or a reduction of the (already negative) gradient of the first line 16. If the frequency falls below a predeterminable frequency value or is even at "0", an adjustment of the alarm value 2 takes place in step d) in the form of a shift of the first line 16 to the left and / or an increase of the (negative) gradient of the first line 16. At the same time, when adjusting the alarm value 2 or its first line 16, a corresponding adjustment of the adjustment value 3 or its second line 17 can take place, in which the second line 17 is also shifted to the left or right and / or its gradient is adjusted.After an adjustment, the first line 16 of the alarm value 2 in the lower area 5 could, for example, run from the xy coordinate 20 l / min / 15 min to the xy coordinate 0.8 l / min / 120 min, in the middle area 6, for example, from the xy coordinate 40 l / min / 7.5 min to the xy coordinate 20 l / min / 15 min and in the upper area 7, for example, from the xy coordinate 50 l / min / 0 min to the xy coordinate 40 l / min / 7.5 min. Furthermore, the second line 17 of the adjustment value after adjustment in the lower area 5 could, for example, run from the xy coordinate 20 l / min / 0 min to the xy coordinate 0.8 l / min / 72 min, in the middle area 6, for example, from the xy coordinate 40 l / min / 3 min to the xy coordinate 20 l / min / 10.5 min, and in the upper area 7, for example, from the xy coordinate 50 l / min / 0 min to the xy coordinate 40 l / min / 6 min. Further possible adjustments of the alarm value 2 and the adjustment value 3 are shown in . Fig. 3 to 6shown schematically. If a liquid extraction process 1.1, 1.2, 1.3, 1.4 is located above the third line 18, the flow rate of the liquid in the liquid line 8 exceeds the first threshold value 9, which is 50 l / min here. This would indicate a pipe break, so that the Fig. 7 shown valve 12 in the liquid line 8 is automatically closed. In this case, a corresponding message can be sent to a resident of the consumption unit. The fourth line 19 represents a second threshold value 10, which here is 300 I. If a liquid withdrawal process 1.1, 1.2, 1.3, 1.4 is located to the right of the fourth line 19, its flow rate exceeds the maximum permissible flow rate per liquid withdrawal process 1.1, 1.2, 1.3, 1.4, whereby the Figure 7The valve 12 shown in the liquid line 8 is also automatically closed. In this case, a corresponding message can also be sent to a resident of the consumption unit.

[0028] The Fig. 3 shows diagram 4 after a first adjustment of the alarm value 2 or its first line 16 and the adjustment value 3 or its second line 17. The adjustment is done separately for the lower area 5, the middle area 6 and the upper area 7 of the third area 23, depending on the frequency of the liquid withdrawal processes 1.1, 1.2, 1.3, 1.4 in areas 5, 6 and 7 to the right of the second line 17 of the adjustment value 3 (in the Fig. 3(not shown). The first line 16 and the second line 17 run parallel to each other in the respective regions 5, 6, 7 and have the same (horizontal) spacing as before the adjustment. The first line 16 and the second line 17 run in regions 5, 6, 7 in such a way that they no longer touch at the boundaries between regions 5 and 6 and 6 and 7.

[0029] The Fig. 4 shows diagram 4 after a second adjustment of the alarm value 2 or its first line 16 and the adjustment value 3 or its second line 17. The adjustment is also carried out separately for the lower area 5, the middle area 6 and the upper area 7 of the third area 23, depending on the frequency of the liquid withdrawal processes 1.1, 1.2, 1.3, 1.4 in areas 5, 6 and 7 to the right of the second line 17 of the adjustment value 3 (in the Fig. 4(not shown). The first line 16 and the second line 17 run parallel to each other in the respective regions 5, 6, 7 and have the same (horizontal) spacing as before the adjustment. The first line 16 and the second line 17 run in regions 5, 6, 7 such that they continue to touch at the boundaries between regions 5 and 6, and between regions 6 and 7.

[0030] The Fig. 5 shows diagram 4 after a third adjustment of the alarm value 2 or its first line 16 and the adjustment value 3 or its second line 17. The adjustment is also carried out separately for the lower area 5, the middle area 6 and the upper area 7 of the third area 23, depending on the frequency of the liquid withdrawal processes 1.1, 1.2, 1.3, 1.4 in areas 5, 6 and 7 to the right of the second line 17 of the adjustment value 3 (in the Fig. 5not shown). The first line 16 and the second line 17 run parallel to each other only in the areas 5 and 6 and have the same (horizontal) distance as before the adjustment. The first line 16 and the second line 17 do not run parallel to each other in the upper area 7. The first line 16 and the second line 17 run in the areas 5, 6, 7 in such a way that they do not touch at the boundaries between the areas 5 and 6 and 6 and 7. Furthermore, in the Fig. 5 a fifth line 20 is shown. If the fluid withdrawal processes 1.1, 1.2, 1.3, 1.4 occur with a frequency above a predeterminable frequency value above the fifth line 20, the height of the third line 18, ie, the value for the first threshold value 9, can be adjusted depending on the frequency.

[0031] The Fig. 6shows diagram 4 after a fourth adjustment of the alarm value 2 or its first line 16 and the adjustment value 3 or its second line 17. The adjustment is also carried out separately for the lower area 5, the middle area 6 and the upper area 7 of the third area 23, depending on the frequency of the liquid withdrawal processes 1.1, 1.2, 1.3, 1.4 in areas 5, 6 and 7 to the right of the second line 17 of the adjustment value 3 (in the Fig. 6 not shown). The first line 16 and the second line 17 run parallel to each other only in the areas 5 and 6 and have the same (horizontal) distance as before the adjustment. The first line 16 and the second line 17 do not run parallel to each other in the upper area 7. The first line 16 and the second line 17 run in the areas 5, 6, 7 in such a way that they touch at the boundaries between the areas 5 and 6 and 6 and 7. Furthermore, in the Fig. 6The fifth line 20 is also shown. If the fluid withdrawal processes 1.1, 1.2, 1.3, 1.4 occur with a frequency above a predeterminable frequency value above the fifth line 20, the height of the third line 18, ie, the value for the first threshold value 9, can be adjusted depending on the frequency.

[0032] The Fig. 7shows a schematic diagram of a consumption unit 30 in the form of a building with a water meter 11. The water meter 11 is arranged in a liquid line 8, by means of which liquid can be conducted from a liquid source 26 to a consumer 25. The water meter 11 has a valve 12 in the manner of a solenoid valve, by means of which the liquid line 8 can be closed to form a pressure chamber 31 in the liquid line 8. The pressure chamber 31 extends from the valve 12 to the consumer 25. Furthermore, the water meter 11 has a pressure sensor 14, by means of which a pressure and thus a pressure drop in the pressure chamber 31 can be determined after the liquid line 8 is closed with the valve 12.The liquid line 8 is closed by the valve 12 when a flow sensor 13 of the water meter 11 detects that the consumer 25 is not drawing any liquid from the liquid source 26 via the liquid line 8. The valve 12, the flow sensor 13, and the pressure sensor 14 are wirelessly or radio-connected to a controller 15 of the water meter 11. The controller 15 is configured and provided for carrying out the method according to the invention.

[0033] With the present invention, leaks can be detected with greater reliability. List of reference symbols

[0034] 1.1, 1.2, 1.3, 1.4Liquid withdrawal process 2Alarm value 3Adjustment value 4Diagram 5Lower range 6Middle range 7High range 8Liquid line 9First threshold 10Second threshold 11Water meter 12Valve 13Flow sensor 14Pressure sensor 15Control 16First line 17Second line 18Third line 19Fourth line 20Fifth line 21First range 22Second range 23Third range 24Fourth range 25Consumer 26Liquid source 27Graph 28X-axis 29Y-axis 30Consumption unit 31Pressure chamber

Claims

1. A method for detecting a leak, comprising at least the following steps: a) capturing a flow volume of a liquid through a liquid line (8) in a multiplicity of liquid removal processes (1.1, 1.2, 1.3, 1.4), wherein a flow rate of the liquid and a flow duration of the liquid per liquid removal process are captured; b) comparing the flow volumes of the liquid of the respective liquid removal processes with an alarm value (2); c) outputting an alarm signal if the flow volume of the liquid of a liquid removal process (1.1, 1.2, 1.3, 1.4) exceeds the alarm value (2); d) adapting the alarm value (2) on the basis of a frequency of the occurrence of the flow volumes of the liquid of the liquid removal processes above an adaptation value (3), wherein the detection of leaks comprises measuring a pressure of the liquid in the liquid line (8), characterized in that at least the adaptation value (3) or the alarm value (2) is separately adaptable for a multiplicity of ranges (5, 6, 7) of the flow rate of the liquid.

2. The method according to claim 2, wherein the flow rate of the liquid and the flow duration of the liquid per liquid removal process are captured in a diagram (4).

3. The method according to claim 2 or 3, wherein, when adapting the alarm value (2) in step d), the adaptation value (3) is adapted on the basis of the alarm value (2) .

4. The method according to any one of the preceding claims, wherein the detection of leaks comprises measuring a flow rate of the liquid through the liquid line (8), and wherein an alarm signal is output when the flow rate of the liquid exceeds a first threshold value (9).

5. The method according to any one of the preceding claims, wherein an alarm signal is output when in step a) the flow volume exceeds a second threshold value (10).

6. The method according to claim 5 or 6, wherein the first threshold value (9) or the second threshold value (10) is adjustable.

7. A water meter (11), comprising a valve (12), a flow sensor (13) for a liquid, a pressure sensor (14) for the liquid, and a controller (15), wherein the valve (12), the flow sensor (13) and the pressure sensor are connected in a data-conducting manner to a controller (15), and wherein the controller (15) is configured to carry out the method according to any one of the preceding claims.