DE102017100416A1 - Method for detecting a leak, monitoring device and computer program for this purpose - Google Patents

Abstract

A method for detecting a leakage by loss of a medium in an at least temporarily closable line network (2) is described. In this case, a flow (V) or pressure (P) of the medium in the line network (2) is measured. It is recognized that there is no leakage when there are standstill phases (S) in which no flow (V) or no pressure change (ΔP) has been measured.

Description

The invention relates to a method for detecting a leak by loss of a medium in an at least temporarily closable line network, wherein a flow and / or pressure of the medium in the line network is measured.

The invention further relates to a monitoring device for detecting a leak by loss of a medium in an at least temporarily closable line network with a sensor for measuring flow and / or pressure of the medium in the line network, and with an evaluation unit.

The invention further relates to a computer program with program code means, which are set up in connection with such a monitoring device for leakage detection.

Such interconnections may be piping systems in which a medium is supplied via the lines to consumers. This is the case, for example, for water pipes in buildings, which are fed via a water inlet with water as the medium. But there are also closed line networks in which no medium is consumed in the normal state, such as. In a heating pipe network of a building heating system.

Leakage can lead to unwanted leakage, which is difficult to detect, especially with low loss of medium, and can lead to damage.

DE 199 44 830 A1 discloses a safety device for shutting off supply lines for liquid and gaseous media, in which not only after reaching a predetermined, maximum permissible flow volume is blocked, but by including and processing the operating state of the taps and small leaks are detected. For this purpose, each water extraction point is equipped with an operating and detecting sensor and transmitting unit. If no water intake point is actuated and a flow is still measured, this is recognized as an indication of low leakage.

DE 200 19 814 U1 discloses a central water safety device in a main water supply with a volumetric counter, which compares the extracted volume with a set volume limit and closes the obturator after reaching the set volume limit. This can prevent major leaks.

DE 698 25 671 T2 discloses an apparatus for indicating a flow caused by a leak in a fluid circuit. For this purpose, a pressure change is monitored, which acts on a partition wall of a special flow sensor.

DE 10 2011 055 759 B4 shows a water and / or natural gas protection system for a building in which a leak is detected by a number of distributed in the building arranged sensors, which then control a central shut-off valve.

Proceeding from this, it is an object of the present invention to provide an improved method for detecting a leak by a loss of media in an at least temporarily closable cable network, as well as a monitoring device and a computer program designed for this purpose.

The object is achieved by the method having the features of claim 1, by the monitoring device having the features of claim 9 and by the computer program having the features of claim 15. Advantageous embodiments are described in the subclaims.

The method recognizes that there is no leakage when there are stoppage periods during which no flow or pressure change has been measured within a predetermined minimum period of time. Conversely, a leakage is detected if such standstill phases do not occur without flow or without pressure change within the specified minimum period of time.

In a corresponding manner, the evaluation unit of the monitoring device is set up for checking whether there are standstill phases in which no flow or no pressure change has been measured within a predetermined minimum period of time. The evaluation unit is set up to detect a leakage, if there are no such standstill phases or, conversely, to detect leakage, when standstill phases are detected. The evaluation unit may be e.g. be set up by suitable programming microcontroller or microprocessor or be designed as executed on a data processing unit computer program which receives either measurement data on the flow or the pressure change or the pressure of a sensor or extracted from sensor data.

So it is conceivable that the sensor is a camera that is aligned with a flow meter. The image evaluation unit can then be set up for image evaluation such that a movement of the camera in a sequence of Images recorded display elements of the flow meter, a flow of medium is detected.

In the same way, it is conceivable that the sensor unit is aligned with a pressure gauge of a pressure sensor. A pressure change can then be detected by image evaluation from a movement e.g. a pointer of the pressure display a pressure sensor are detected, which was taken with a sequence of images.

For the purposes of the present invention, the term "no flow" or "no change in flow" also means the variant that the measured flow rate of the medium is less than a predetermined flow offset value or the measured pressure change of the medium is less than a predetermined pressure change offset value is. With the help of such offset values, the sensitivity of the leakage detection can be reduced.

In the event of leakage detection by loss of a medium in an at least temporarily closable line network, in which the pressure of the medium in the line network is measured, the trend of the measured pressure values can be determined and a leak can be detected, if a change of the trend values over a predetermined minimum trend period is present. The trend can be determined, for example, by filtering periodic fluctuations from the measured sequence of pressure values and / or pressure change values. This can e.g. by taking averages of the sequence of pressure values and / or pressure change values. It exploits the fact that the pressure remains constant in a sealed line network without leakage despite the fluctuations during operation over a longer observation period on average. In the event of a leak, such as a microleakage, the pressure also decreases on average over time. This is then recognizable by the trend.

In addition, it is conceivable that a further leakage detection occurs when the measured flow rate exceeds a predetermined flow rate value or when the measured pressure falls below a predetermined pressure limit. The predetermined flow rate value may be, for example, an upper limit value for an amount of the medium which is fed into the line network in a predetermined period of time. With the specification of such a maximum consumption per unit of time, leaks can be detected by the outflow of large quantities of the medium, in order then, e.g. automatically shut off a central obturator and thus prevent further inflow of medium in the line network.

To detect a leak, a predetermined monitoring period can be defined. It is then checked whether within this predetermined monitoring period, no state is detected in which no flow or no pressure change has been measured. Then a leak is detected from the fact that there is no standstill phase during the entire monitoring period. This predetermined monitoring period should be in the range of at least one hour and preferably be selected in the range of twelve to 24 hours. It is exploited that a temporarily closable cable network is not used at least once over such a longer period of the predetermined monitoring period, so that in this period of no use a hibernation occurs in which no medium taken from the line network and thus no medium is supplied to the line network and thus no flow of the medium is sensed or in which the pressure does not change.

• 1 - Skizze eines Gebäudes mit einem Wasserleitungsnetz als Leitungsverbund und einer Überwachungseinrichtung zur Leckageerkennung;
• 2 - Skizze eines Gebäudes mit einer Heizungsanlage als Leitungsverbund mit einer Überwachungseinrichtung zur Leckageerkennung in Abhängigkeit von einer Druckänderung;
• 3 - beispielhaftes Diagramm des Durchflusses von Wasser über die Zeit mi Stillstandsphasen;
• 4 - beispielhaftes Diagramm des Durchflusses von Wasser in einem Leitungsverbund mit einem Durchfluss-Offsetwert;
• 5 - beispielhaftes Diagramm der Druckänderung in einem Heizungs-Leitungsverbund mit Stillstandsphasen;
• 6 - beispielhaftes Diagramm von gemessenen Druckwerten in einem Heizungs-Leitungsverbund mit der zugehörigen Trendkurve.

The invention will be explained in more detail with reference to embodiments with the accompanying drawings. Show it:

• 1 - Sketch of a building with a water supply network as a line network and a monitoring device for leakage detection;
• 2 - Sketch of a building with a heating system as a line network with a monitoring device for leakage detection in response to a pressure change;
• 3 - exemplary diagram of the flow of water over time mi Standstill phases;
• 4 exemplary diagram of the flow of water in a line network with a flow offset value;
• 5 - exemplary diagram of the pressure change in a heating line network with standstill phases;
• 6 - Exemplary diagram of measured pressure values in a heating line network with the associated trend curve.

1 shows a sketch of a building 1 with a line network 2 in the form of water pipes leading to consumption points 3 to lead. The consumption points 3 are exemplified by faucets. But it can also other consumption points, such as washing machines, dishwashers, etc. to the line network 2 be connected. The line network 2 is via a supply line 4 fed from the outside with a medium (water). As usual, a central stopcock 5 available to shut off the inlet, if necessary in case of leakage.

Furthermore, the input side is usually behind the stopcock 5 a sensor 6 for measuring the flow of the medium, ie a consumption meter available. This has indicators that move at a flow.

In the illustrated embodiment, a camera 7 on the sensor 6 aligned over time a sequence of images from the display elements of the sensor 6 take. The camera 7 is with an evaluation unit 8th connected.

The evaluation unit 8th may be, for example, a data processing unit, such as a computer or a control logic for building automation. In the illustrated embodiment, the evaluation unit 8th For example, set up by suitable programming to from the sequence of images, the presence of a movement of the display elements of the sensor 6 to detect. If a movement of image content is detected in successive images, this is a measure of the presence of flow. The flow rate results from the size of the change in movement of the image contents, ie from the extent to which the recorded display elements move.

It is also conceivable that the with the sensor 6 Measured flow directly as a signal to the evaluation unit 8th is transmitted. The sensor 6 (Flow meter) can also be coupled with other detection units to those with the sensor 6 measured flow or pressure values, for example, visually or otherwise to capture and to the evaluation 8th transferred to.

Around now a leak in the cable network 2 For example due to dripping faucets or other leaks in the pipeline network, the water flow is continuously measured and the flow is measured as a volume flow with the evaluation unit 8th eg evaluated by suitable programming. In the operation of a building, the water consumption is unpredictable and usually changes constantly. In such a temporarily closable cable network 2 but there are always standstill phases S, in which no medium to the line network 2 is supplied because the line network 2 should be completely closed in the standstill phases S. The evaluation unit 8th Check now whether over time t such standstill phases S are to be observed, in which no flow is measured. For this purpose, if appropriate, a flow offset value Voffset can also be defined, below which a standstill phase S is assumed. This may possibly reduce the sensitivity somewhat.

If no standstill phase S has been detected over a certain period of time, then the occurrence of a leakage is concluded and an alarm can possibly be output. It is also conceivable that the evaluation unit 8th the stopcock 5 , that is, the shut-off valve controls to a further inflow of the medium in the line network 2 to prevent. As a monitoring period T _Ü a suitable for the operation of the building period is set. If necessary, this can be adaptively adapted and optimized over time. Suitable monitoring periods T _Ü of at least one hour, preferably monitoring periods T _Ü of about twelve to 24 hours. Within such large monitoring periods T _Ü of at least one hour, there are usually always such standstill phases S during operation of a building in which the line network 2 is temporarily completed and thus no flow V should be present.

figure 2 leaves a sketch of a building 1 with a heating pipe network as a line network 2 detect. The heating pipe network is with a heating system 9 as well as with decentralized distributed in individual rooms radiators 10 and thermostatic valves arranged thereon 11 connected. The line network 2 also has a sensor 12 for measuring the water pressure in the pipeline network 2 , The measured water pressure or pressure change is then sent to the evaluation unit 8th transfer. This in turn can be done either by a direct line connection between the sensor 12 and the evaluation unit 8th for transmitting the measuring signals or indirectly eg with a camera 7 carried out on the display unit of the sensor 12 is aligned.

Even when operating such a heating system usually occur pressure fluctuations. But there are also standstill phases in which there is no pressure change. Only in the case of leakage would such standstill phases not occur.

In particular, in such a heating system as a line network 2 The presence of a leak due to the absence of stoppage phases S can be determined very well via the trend of the measured pressure values P (t). For this purpose, the measured pressure values P (t) are filtered in order to eliminate the periodic changes. This can be done, for example, by averaging. The smoothed signal curve reflects the trend. If this trend curve falls, there is no standstill phase S in which no pressure change was measured. Rather, it is through the falling trend constantly there is a pressure change caused by the leakage.

3 shows an exemplary diagram of a measured flow V of a medium in a temporarily closable cable network over the time t. The flow is measured as a volume flow with the unit m3 / s. The time t can be plotted, for example, in hours. There is a monitoring period T _Ü predetermined. The monitoring period _T.sub.U should be more than one hour and may, for example, be set to a value in the range of six to 24 hours. If necessary, it can also be adapted adaptively in order to avoid false identifications due to too short or too long periods of time.

It is now checked whether within the specified monitoring period T _Ü at least one standstill phase S occurs, in which no flow V was detected. It can be seen that such standstill phases occur in the flow rate profile measured by way of example in two time periods Δt1 and Δt2. This suggests that the temporarily closable cable network 2 is actually completely closed in these periods .DELTA.t1 and .DELTA.t2. This is an indication that there is no leakage in the piping 2 is present. In the remaining times is the line network 2 taken from the medium, since a flow V was measured with the flow indicating an inflow of the spent medium. However, these periods show a normal operation of the line network 2 on, which is intended for the removal of medium, such as, water intended.

The dashed trace shows a situation in which no standstill phases S are present within the predetermined monitoring period T _Ü . Although the removal is reduced in the periods .DELTA.t1 and .DELTA.t2 compared to the consumption times. However, a measurable flow V, which indicates a leakage or at least a microleakage, still occurs during these periods.

4 shows an exemplary diagram with the specification of a flow offset value Voffset. Here, a stoppage phase S is already detected when the flow V is less than the predetermined flow offset value Voffset. Thus, the situation "no flow" is already detected, if there is still a low flow rate if necessary. Thus, the sensitivity of the leakage detection can be slightly reduced. This predetermined flow offset value Voffset can be set by the user and possibly by the user or in particular by the evaluation unit 8th adaptively adapted to improve the reliability of leakage detection.

5 shows an exemplary diagram of pressure values P over the time t. Again, a predetermined monitoring period T _{Ü is} provided. It is now checked whether during operation, for example. Within the predetermined monitoring period T _Ü standstill phases S occur in which no pressure change .DELTA.P is observed. During operation of a line network, such as a heating pipe network of a building heating system, which is filled with water at a pressure above atmospheric pressure, occur during operation by the heating system, in particular by the pump, pressure changes. However, these are periodic fluctuations. During operation, there are always phases in which the heating system at least briefly rests and then the pressure should be constant. In the event of a leak, however, such standstill phases would not occur because the pressure through the leakage always changes (reduces). The absence of stoppage phases is then a sign of the presence of a leak.

Such a lack of standstill phases can best be determined by evaluating the trend of the measured pressure values. For this purpose, the periodic fluctuations are filtered out of the measured sequence of pressure values P or pressure change values ΔP. This is in 6 outlined as an example. To determine the trend drawn with a dashed line, for example, the average values of the sequence of pressure values P can be determined. Suitable for this is, for example, the formation of the moving average (the moving average). This trend is a measure of the pressure change. Now, as sketched with the dashed falling curve of the pressure values for the leakage case, this trend is constantly decreasing, there are no stoppage phases without pressure change. This is a leak in the line network 2 in front.

For a line network 2 without leakage, the trend would be horizontal, as indicated by the second solid horizontal curve.

The above-described detection of leakage in a line network 2 can be done with a computer program with program code means by programming a measured value analysis, the computer program when running from a data processing unit from the sequence of measured values for the flow V or the pressure P or the pressure change .DELTA.P checks whether to observe standstill phases S without flow or without pressure change are. If such standstill phases S are absent, a leak is detected and, if appropriate, an alarm is output visually, acoustically or by a message and optionally a central shut-off valve is activated.

It is also conceivable that a standstill phase is only detected when no flow or no pressure change in a predetermined minimum time T _min occurs. The eg in 3 outlined periods .DELTA.t1 and .DELTA.t2 would then have to be greater than the predetermined minimum period T _min to indicate a stoppage phase. Thus, very brief interruptions of the flow V or the pressure change .DELTA.P can not be used for leakage and filtered out so to speak.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19944830 A1 [0006]
• DE 20019814 U1 [0007]
• DE 69825671 T2
• DE 102011055759 B4 [0009]

Claims (15)

A method for detecting a leakage by loss of a medium in an at least temporarily closable line network (2), wherein a flow (V) and / or pressure (P) of the medium in the line network (2) is measured, characterized by detecting that no leakage If there are standstill phases (S) in which no flow (V) or no pressure change (ΔP) has been measured. Method according to Claim 1 , characterized in that there is no flow (V) when the measured flow rate of the medium is less than a predetermined flow _offset value (V _Offset ). Method according to Claim 1 or 2 , characterized in that there is no pressure change (ΔP) when the measured pressure change (ΔP) of the medium is less than a predetermined pressure change _offset value (P _Offset ). Method according to one of Claims 1 to 3 , characterized by detecting a leak, if within a predetermined monitoring period (T _Ü ) no state is detected in which no flow (V) or no pressure change (ΔP) has been measured. A method of detecting leakage by loss of a medium in an at least temporarily sealable conduit network (2), wherein the pressure (P) of the medium in the conduit network (2) is measured, characterized by determining the trend (T) of the measured pressure values and detecting a Leakage, if there is a change of the trend values (T (t)) over a predetermined monitoring period (T _Ü ). Method according to Claim 5 characterized by determining the trend (T) by filtering periodic variations from the measured sequence of pressure values (P (t)) and / or pressure change values (ΔP (t)). Method according to Claim 6 characterized by determining the trend by forming averages of the sequence of pressure values (P (t)) or pressure change values (ΔP (t)). Method according to one of the preceding claims, characterized by detecting a leakage when the measured flow rate (ΔV) exceeds a predetermined flow rate value (V _max ), or when the measured pressure (P) falls below a predetermined pressure limit (P _min ). Monitoring device for detecting a leak by loss of a medium in an at least temporarily closable line network (2) with a sensor (6) for measuring flow (V) and / or pressure (P) of the medium in the line network (2), and with a Evaluation unit (8), characterized in that the evaluation unit (8) for checking whether there are standstill phases (S), in which no flow (V) or no pressure change (.DELTA.P) has been measured, and for detecting a leakage is established, if there are no such standstill phases (S). Monitoring device according to Claim 9 , characterized in that the sensor (6) has a camera (7), which is aligned with a flow meter or the pressure display of a pressure sensor, wherein the evaluation unit (8) is arranged for image evaluation such that from a movement of the camera ( 7) of the flow meter display elements or the pressure display, a sequence of images is detected, a flow (V) or a pressure change (ΔP) of medium is detected. Monitoring device according to Claim 9 , characterized in that the sensor (6) is a pressure sensor in the water cycle of a heating system, which is set up for continuous measurement of the water pressure. Monitoring device according to one of Claims 9 to 11 , characterized in that the evaluation unit (8) is arranged to detect a stoppage phase (S) when the measured flow rate (V) of the medium is less than a predetermined flow _offset value (V _offset ) or if the measured pressure change (ΔP) of the medium is less than a predetermined pressure change _offset value (P _offset ). Monitoring device according to one of Claims 9 to 12 , characterized in that the evaluation unit (8) is adapted to detect a leak, if within a predetermined monitoring period (T _Ü ) no state is detected in which no flow (V) or no pressure change (ΔP) has been measured. Monitoring device after a he Claims 9 to 13 Characterized in that the evaluation unit (8) for determining the trend (T) of the measured pressure values (P (t)) is set up and for detecting a leakage when a predetermined monitoring period (T _Ü) a change in the trend values (T ( t)). Computer program with program code means, used in conjunction with the monitoring device according to any one of Claims 9 to 14 to Checking whether there are standstill phases (S) in which no flow (V) or no pressure change (ΔP) has been measured and are set up to detect leakage, if such standstill phases (S) are present when the computer program is executed on a data processing unit ,

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