Method and micro-leakage detection device for micro-leakage detection in a fluid system

Abstract

A method for micro-leakage detection in a fluid system (10), preferably installed in a drinking water system in a building (11), wherein the fluid system (10) has a fluid conduit (12) with a fluid valve (14), wherein a fluid flow through the fluid conduit (12) is stopped when the fluid valve (14) is closed, and wherein a fluid flow through the fluid conduit (12) is allowed when the fluid valve (14) is open. The method comprises the steps of measuring a fluid flow through the fluid conduit (12) by a flow meter (16). A conduit temperature of the fluid conduit (12) is measured by at least one conduit temperature sensor (17a, 17b). The conduit temperature is analyzed for micro-leakage detection when no fluid flow is measured by the flow meter (16), in particular due to a stop of a fluid flow through the fluid conduit (12) by the fluid valve (14) being closed or when a fluid flow through the fluid conduit (12) is stopped by the fluid valve being closed.

Description

Technical Field

[0001] This invention relates to a method for detecting microleakage in fluid systems. Furthermore, this invention relates to a microleakage detection device suitable for detecting microleakage in fluid systems. Background Technology

[0002] US 2019 / 0128762 A1 discloses a device for fluid flow detection. This device utilizes signals provided by a pipe temperature sensor and signals provided by an ambient temperature sensor. A low-flow algorithm attempts to detect flow leakage, such as a dripping faucet. If no leakage occurs during quiet periods, the ambient and pipe temperatures will generally be similar. Conversely, if a low-flow leakage occurs during quiet periods, there will be a generally significant difference between the ambient and pipe temperatures.

[0003] Other prior art is disclosed in EP 2 180 304 A1, GB 2 572 274 A, US 4 336 708 A, US 10 527 516 B2 and JP6 611 650 B2.

[0004] Against this backdrop, a novel method and a novel microleak detection device for detecting microleakage in fluid systems are provided. Summary of the Invention

[0005] A novel method for detecting microleakage in fluid systems includes at least the following steps:

[0006] The flow rate of fluid passing through a fluid pipe is measured by a flow meter;

[0007] The pipe temperature of the fluid pipe is measured by at least one pipe temperature sensor;

[0008] When fluid flow is not measured by the flow meter, especially when the fluid flow through the fluid pipe stops due to the closure of the fluid valve, analyze the pipe temperature for micro-leak detection.

[0009] A novel method for detecting microleakage is based on both flow measurement by a flow meter and pipe temperature measurement by at least one pipe temperature sensor. This novel method allows for very simple and reliable microleakage detection in fluid systems. Microleakages detectable using this invention are below the measurement resolution or range of the flow meter.

[0010] The pipe temperature can be measured by at least one pipe temperature sensor when fluid flow through the pipe is permitted and when fluid flow through the pipe is stopped. The measured fluid flow is analyzed for leak detection only when no fluid flow is measured by the flow meter. In this case, at least one pipe temperature sensor is activated and measures the pipe temperature both when fluid flow is measured by the flow meter and when no fluid flow is measured by the flow meter. However, the measured pipe temperature is analyzed for micro-leak detection only when no fluid flow is measured by the flow meter.

[0011] Alternatively, the pipe temperature for micro-leak detection can be measured and analyzed only when the fluid flow through the pipe is stopped. In this case, at least one pipe temperature sensor is not activated when the fluid flow is measured by the flow meter. Then, when the fluid flow is not measured by the flow meter, at least one pipe temperature sensor becomes active. In this case, the pipe temperature is measured and analyzed only when the fluid flow is not measured by the flow meter for micro-leak detection.

[0012] According to a first embodiment of the method for detecting microleakage, it includes the additional step of: calculating the time gradient of the pipe temperature when no fluid flow is measured by a flow meter after the fluid flow through the pipe has stopped. If the time gradient of the pipe temperature differs from a first reference value by more than a first threshold, and if no flow is measured by the flow meter, a microleakage is detected.

[0013] According to a second embodiment of the method for detecting microleakage, it includes the additional steps of: measuring the pipe temperature of the fluid pipe using a first pipe temperature sensor and a second pipe temperature sensor located at different locations in the fluid pipe; calculating the temperature difference between the pipe temperatures measured by the first and second pipe temperature sensors when no fluid flow is measured by a flow meter within a defined time interval; and detecting a microleakage if the temperature difference between the pipe temperatures differs from a second reference value by more than a second threshold, and if no flow is measured by the flow meter.

[0014] The first and second embodiments described above are preferred. They are independent of ambient temperature and do not require the measurement of ambient temperature. Such ambient temperature-independent microleak detection is very simple and reliable. The first and second embodiments can be used in combination, meaning that a microleak is detected if the time gradient of the pipe temperature differs from a first reference value by more than a first threshold and / or if the temperature difference between pipe temperatures differs from a second reference value by more than a second threshold.

[0015] Claim 15 defines a novel microleak detection device suitable for detecting microleakage in fluid systems. Attached Figure Description

[0016] Preferred embodiments of the present invention are provided by the dependent claims and the following description.

[0017] The exemplary embodiments will be explained in more detail based on the accompanying drawings, wherein:

[0018] Figure 1 A schematic diagram of the fluid flow system is shown;

[0019] Figure 2 A signal flow diagram illustrating the first embodiment is shown;

[0020] Figure 3 A signal flow diagram illustrating the second embodiment is shown;

[0021] Figure 4 A signal flow diagram illustrating the third embodiment is shown.

[0022] Figure 5 A timing diagram further illustrating the first embodiment is shown.

[0023] Figure 6 A timing diagram further illustrating the second embodiment is shown.

[0024] Figure 7 A timing diagram further illustrating the third embodiment is shown. Detailed Implementation

[0025] Figure 1 A schematic diagram of a fluid flow system 10 (i.e., a drinking water system) for building 11 is shown. The fluid flow system 10 includes a fluid conduit 12 extending at least partially inside building 11. The fluid conduit 12 is connected to a main water conduit 13 extending outside building 11. The fluid conduit 12 includes a fluid valve 14. The fluid valve 14 may be a faucet. When the fluid valve 14 is closed, the flow of fluid through the fluid conduit 12 is stopped. When the fluid valve 14 is open, the flow of fluid through the fluid conduit 12 is permitted. The fluid conduit 12 may be made of a metal such as copper or a plastic such as polypropylene.

[0026] This invention relates to a method for detecting microleakage in a fluid system 10, and to a microleakage detection device. Figure 1 Such a microleakage detection device 15 is shown.

[0027] The micro-leakage detection device 15 receives signals from at least the flow meter 16 and from at least one pipe temperature sensor 17a, 17b.

[0028] The flow meter 16 is associated with the fluid conduit 12 and measures the flow rate of the fluid passing through the fluid conduit 12.

[0029] Flow meter 16 has a measurement range or measurement resolution. Flow meter 16 is configured to measure the fluid flow rate through fluid conduit 12 when fluid valve 14 is open (meaning there is regular fluid consumption across fluid valve 14). However, when fluid valve 14 is closed, irregular fluid consumption may occur due to microleakage. Microleakage causes a certain fluid flow rate below the measurement range or measurement resolution of flow meter 16. Therefore, microleakage cannot be detected by flow meter 16 itself (i.e., by flow meter 16 alone).

[0030] At least one pipe temperature sensor 17a, 17b is also associated with the fluid pipe 12 and measures the pipe temperature of the fluid pipe 12.

[0031] Figure 1 A first pipe temperature sensor 17a and a second pipe temperature sensor 17b are shown. Furthermore, Figure 1 An ambient temperature sensor 18 is shown for measuring the ambient temperature inside a building. The ambient temperature sensor 18 can be located near the fluid conduit 12. Only one of the first temperature sensor 17a and the second temperature sensor 17b, along with the flow meter 16, are mandatory components of the invention. The ambient temperature sensor 18 is an optional component. If the ambient temperature sensor 18 is present, it is preferably located near the fluid conduit 12.

[0032] The first embodiment of the present invention utilizes only at least one pipe temperature sensor 17a, 17b and flow meter 16.

[0033] The second embodiment of the present invention utilizes a first pipe temperature sensor 17a, a second pipe temperature sensor 17b, and a flow meter 16.

[0034] The micro-leakage detection device 15 has an interface 15a configured to receive signals or data from a flow meter 16 and an interface 15b configured to receive signals or data from at least one pipe temperature sensor 17a, 17b.

[0035] The third embodiment utilizes at least one pipe temperature sensor 17a, 17b, a flow meter 16, and an ambient temperature sensor 18. In this case, the micro-leakage detection device 15 has an interface 15c configured to receive signals or data from the ambient temperature sensor 18.

[0036] The method for detecting microleakage in fluid system 10 includes at least the following steps:

[0037] The flow rate of the fluid passing through the fluid pipe 12 is measured by the flow meter 16;

[0038] The pipe temperature of the fluid pipe 12 is measured by at least one pipe temperature sensor 17a, 17b;

[0039] When the fluid flow rate is not measured by the flow meter 16, the pipe temperature is analyzed for micro-leak detection because the fluid flow rate through the fluid pipe 12 stops due to the closure of the fluid valve 14 or when the fluid flow rate through the fluid pipe 12 stops due to the closure of the fluid valve 14.

[0040] When fluid flow through fluid conduit 12 is permitted and when fluid flow through fluid conduit 12 is stopped, the conduit temperature of fluid conduit 12 can be measured by at least one conduit temperature sensor 17a, 17b, wherein the measured fluid flow is analyzed for leak detection only when no fluid flow is measured by flow meter 16.

[0041] In this scenario, at least one pipe temperature sensor 17a, 17b is activated and measures the pipe temperature when the fluid flow rate is measured by the flow meter 16 and when the fluid flow rate is not measured by the flow meter 16. However, the measured pipe temperature is only analyzed for micro-leak detection when the fluid flow rate is not measured by the flow meter 16.

[0042] Alternatively, the pipe temperature of fluid pipe 12 may be measured and analyzed for micro-leak detection only when the flow rate of fluid through fluid pipe 12 is stopped by fluid valve 14.

[0043] In this alternative scenario, when fluid flow rate is measured by flow meter 16, at least one pipe temperature sensor 17a, 17b is either inactive or becomes inactive. When fluid flow rate is not measured by flow meter 16, at least one pipe temperature sensor 17a, 17b is either activated or becomes active. In this case, pipe temperature is both measured and analyzed for micro-leak detection only when fluid flow rate is not measured by flow meter 16.

[0044] The method for detecting microleakage is based on both flow rate measurement by flow meter 16 and pipe temperature measurement by at least one pipe temperature sensor 17a, 17b. This method allows for very simple and reliable microleakage detection in fluid system 10. The present invention allows for the detection of microleakage that causes fluid flow rates below the measurement range or resolution of flow meter 16.

[0045] The microleakage detection device 15 is configured to perform the above-described method steps. Interface 15a of the microleakage detection device 15 is configured to receive signals or data from a flow meter 16 that measures the flow rate of fluid through the fluid conduit 12. Interface 15b of the microleakage detection device 15 is configured to receive signals or data from at least one pipe temperature sensor 17a, 17b that measures the pipe temperature of the fluid conduit 12.

[0046] The processor 15d of the microleak detection device 15 is configured to detect microleakage by analyzing the pipe temperature provided by at least one pipe temperature sensor 17a, 17b when no fluid flow rate is measured by the flow meter 16. The microleak detection device 15 further includes a memory 15e.

[0047] If the pipe temperature of the fluid pipe 12 is measured and analyzed only when the fluid flow rate is not measured by the flow meter 16, then the processor 15d of the microleak detection device 15 is configured to activate at least one pipe temperature sensor 17a, 17b when the fluid flow rate is not measured by the flow meter 16.

[0048] As described above, the first embodiment of the present invention utilizes only at least one pipe temperature sensor 17a and / or 17b and a flow meter 16. In the following description of the first embodiment, it is assumed that the pipe temperature sensor 17a is used for measuring the pipe temperature. In this first embodiment, the time gradient of the pipe temperature measured by the pipe temperature sensor 17a is calculated when no fluid flow is measured by the flow meter 16 after the fluid flow through the fluid pipe 12 has stopped. The cessation of fluid flow can be detected based on the signal provided by the flow meter 16, i.e., when the fluid flow is measured by the flow meter 16 and subsequently no fluid flow is measured by the flow meter 16. The time gradient is also commonly referred to as the gradient over time. If the time gradient of the pipe temperature differs from a first reference value by more than a first threshold, and if no flow is measured by the flow meter 16, a microleak is detected.

[0049] Figure 2 A signal flow diagram of a first embodiment of the present invention is shown. In step 20, flow meter 16 measures the flow rate of fluid through fluid pipe 12. In step 21, pipe temperature sensor 17a measures the pipe temperature of fluid pipe 12.

[0050] In step 22, it is determined whether flow meter 16 measures the fluid flow rate through fluid conduit 12. If it is determined in step 22 that flow meter 16 measures the fluid flow rate through fluid conduit 12, the method returns to step 20. If it is determined in step 22 that flow meter 16 does not measure the fluid flow rate through fluid conduit 12, the method proceeds to step 23.

[0051] In step 23, it is determined whether flow meter 16 is not measuring the fluid flow rate through the pipe. If not, the method returns to step 20. If so, the method proceeds to step 24. In step 24, the time gradient (also commonly referred to as the gradient over time) of the pipe temperature measured by pipe temperature sensor 17a is calculated.

[0052] Then, in step 25, it is determined whether the time gradient of the pipe temperature differs from the first reference value by more than a first threshold.

[0053] If the time gradient of the pipe temperature differs from the first reference value by no more than a first threshold, then no microleakage is detected in step 26. If the time gradient of the pipe temperature differs from the first reference value by more than the first threshold, and if the fluid flow rate is still not measured by the flow meter 16, then a microleakage is detected in step 27.

[0054] In conjunction with the first embodiment, alternatively, the pipe temperature sensor 17b can be used to measure the pipe temperature. Furthermore, two pipe temperature sensors 17a and 17b can be used, and the average pipe temperature can be calculated.

[0055] The first reference value for the time gradient of the pipe temperature can be determined as follows: If no fluid flow is measured after the fluid flow through the pipe has stopped, the time gradient of the pipe temperature is calculated and stored. An average value is calculated based on the stored time gradient. A first threshold is determined based on this average value.

[0056] The average value can be multiplied by a safety factor to determine the first reference value.

[0057] The above method is performed by the microleakage detection device 15 at a defined sampling rate or at a defined sampling rate. The calculation of the time gradient can be performed at each sampling moment of the sampling rate. However, the calculated time gradient may not be stored at every sampling moment of the sampling rate. The calculated time gradient may be stored only once after its calculation, for example, every 10, 20, 50, or 100 times. These calculated time gradients can be stored in a circular buffer of the memory 15e of the microleakage detection device 15. The circular buffer may have a defined buffer size. If the circular buffer is completely full, the average value can be calculated based on the stored time gradients. If the circular buffer is not completely full, the average value may not be calculated. If the circular buffer is completely full, and if a newly calculated time gradient is to be stored, the oldest stored time gradient will be replaced by the newly calculated time gradient, and the average value will be recalculated.

[0058] The calculated time gradient can only be stored and used to calculate the average if the absolute value of the difference between the calculated time gradient and the previously calculated time gradient, or the absolute value of the difference between the calculated time gradient and the average of the previously stored time gradients, is below the corresponding threshold.

[0059] Figure 5 A timing diagram is shown to further illustrate the first embodiment of the present invention. Figure 5 The fluid velocity 50 as a function of time t and the pipe temperature 51 as measured by pipe temperature sensor 17a are shown.

[0060] At time points t1, t3, and t5, the corresponding fluid flow rate 50 through fluid conduit 12 begins. At time points t2, t4, and t6, the corresponding fluid flow rate 50 through fluid conduit 12 stops due to the closure of fluid valve 14.

[0061] At time points t2, t4, and t6, after the fluid flow through fluid pipe 12 has stopped, the time gradient 52 of pipe temperature 51 is calculated. If the calculated time gradient 52 of pipe temperature 51 differs from a first reference value by more than a first threshold, and if no flow is measured by flow meter 16, a microleak is detected.

[0062] exist Figure 5 In the calculation, the time gradient 52 calculated at time points t2 and t4 differs from the first reference value by no more than a first threshold. Therefore, no microleakage was detected at time points t2 and t4. The time gradient 52 calculated at time point t6 differs from the first reference value by more than the first threshold. Therefore, a microleakage 53 was detected at time point t6. The first reference value can correspond to the average value of the time gradients 52 calculated at time points t2 and t4.

[0063] As described above, the second embodiment of the present invention utilizes a first pipe temperature sensor 17a and a second pipe temperature sensor 17b, as well as a flow meter 16.

[0064] In this second embodiment, the pipe temperature of the fluid pipe 12 is measured by a first pipe temperature sensor 17a and a second pipe temperature sensor 17b located at different positions on the fluid pipe 12.

[0065] Pipe temperature sensors 17a and 17b are located at different distances from the fluid valve 14. Pipe temperature sensor 17b is positioned closer to the fluid valve 14 than pipe temperature sensor 17a. The distance between pipe temperature sensors 17a and 17b can be at least 20 cm.

[0066] When no fluid flow is measured by flow meter 16 within a defined time interval, the temperature difference between the pipe temperatures measured by the first pipe temperature sensor 17a and the second pipe temperature sensor 17b is calculated. If the temperature difference between these pipe temperatures differs from a second first reference value by more than a second threshold, and if no flow is measured by flow meter 16, a microleak is detected.

[0067] Figure 3 A signal flow diagram of a second embodiment of the present invention is shown.

[0068] In step 30, flow meter 16 measures the flow rate of the fluid through fluid pipe 12. In step 31, first pipe temperature sensor 17a measures the pipe temperature of fluid pipe 12. In step 32, second pipe temperature sensor 17b measures the pipe temperature of fluid pipe 12.

[0069] In step 33, it is determined whether flow meter 16 is not measuring the fluid flow rate through the pipe. If this is not the case, the method returns to step 30. If this is the case, the method proceeds to step 34.

[0070] In step 34, it is determined whether the flow meter 16 has not measured any fluid flow through the fluid conduit 12 within a defined time interval after the fluid flow has stopped. If this is not the case, the method returns to step 30. If this is the case, the method proceeds to step 35.

[0071] In step 35, the temperature difference between the pipe temperatures measured by the first pipe temperature sensor 17a and the second pipe temperature sensor 17b is calculated.

[0072] Then, in step 36, it is determined whether the temperature difference from the second reference value exceeds the second threshold.

[0073] If the temperature difference does not exceed the second threshold from the second reference value, then no microleakage is detected in step 37.

[0074] If the temperature difference differs from the second reference value by more than the second threshold, and if the fluid flow rate is still not measured by the flow meter 16, a microleak is detected in step 38.

[0075] The second reference value is determined as follows: If no fluid flow rate is measured within a defined time interval, the temperature difference between the pipe temperatures measured by the first pipe temperature sensor 17a and the second pipe temperature sensor 17b is calculated and stored. An average value is calculated based on the stored temperature difference. A second threshold value is determined based on this average value.

[0076] The average value can be multiplied by a safety factor to determine the second reference value.

[0077] The calculation of the temperature difference between the pipe temperatures measured by the first pipe temperature sensor 17a and the second pipe temperature sensor 17b can be performed at each sampling moment of the sampling rate. However, the temperature difference may not be stored at each sampling moment of the sampling rate. The calculated temperature difference may be stored once after its calculation, for example, every 10, 20, 50, or 100 times. The calculated temperature difference may be stored in a ring buffer of the memory 15e of the microleak detection device 15. The ring buffer may have a defined buffer size. If the ring buffer is completely full, an average value can be calculated. If the ring buffer is not completely full, an average value may not be calculated. If the ring buffer is completely full, and if a newly calculated temperature difference between the pipe temperatures measured by the first pipe temperature sensor 17a and the second pipe temperature sensor 17b is to be stored, the oldest stored temperature difference will be replaced by the newly calculated temperature difference, and the average value will be recalculated.

[0078] The calculated temperature difference can only be stored and used to calculate the average value if the absolute value of the difference between the calculated temperature difference and the previously calculated temperature difference or the absolute value of the difference between the calculated temperature difference and the average value of the previously stored temperature differences is below a threshold.

[0079] Figure 6 A timing diagram further illustrating a second embodiment of the present invention is shown. Figure 6 The fluid velocity 60 as a function of time t and the pipe temperatures 62 and 63 as measured by pipe temperature sensors 17a and 17b are shown.

[0080] At time points t1, t3, and t5, the corresponding fluid flow rate 60 through fluid conduit 12 begins. At time points t2, t4, and t6, the corresponding fluid flow rate 60 through fluid conduit 12 ceases.

[0081] When, at time points t2, t4, and t6, no fluid flow is measured by flowmeter 16 within a defined time interval after the fluid flow through fluid pipe 12 stops due to the closure of fluid valve 14, the temperature difference 63 between the pipe temperatures 61 and 62 measured by the first pipe temperature sensor 17a and the second pipe temperature sensor 17b is calculated. The cessation of fluid flow can be detected based on a signal provided by flowmeter 16, i.e., when fluid flow is measured by flowmeter 16 and subsequently no fluid flow is measured by flowmeter 16.

[0082] If the temperature difference 63 between the pipe temperatures 61 and 62 differs from the second reference value by more than the second threshold, and if no flow rate is measured by the flow meter 16, a microleak 64 is detected.

[0083] exist Figure 6In the above scenario, the temperature difference 63 calculated over a defined time interval after time points t2 and t4 does not differ from the second reference value by more than the second threshold. Therefore, no microleakage was detected. The temperature difference 63 calculated over a defined time interval after time point t6 differs from the second reference value by more than the second threshold. Therefore, a microleakage 64 was detected. The second reference value can correspond to the average value of the temperature differences 63 calculated over the defined time intervals after time points t2 and t4.

[0084] The first and second embodiments described above are preferred. They do not require measurement of ambient temperature. Such microleak detection, independent of ambient temperature, is very simple and reliable.

[0085] The first and second embodiments can be used in combination. Therefore, microleakage can be detected if the time gradient of the pipe temperature differs from the first reference value by more than a first threshold, or if the temperature difference between the pipe temperatures differs from the second reference value by more than a second threshold.

[0086] The third embodiment utilizes an ambient temperature sensor 18.

[0087] In this third embodiment, the ambient temperature is measured by the ambient temperature sensor 18. When no fluid flow rate is measured by the flow meter 16 within a defined time interval, the temperature difference between the pipe temperature and the ambient temperature is calculated.

[0088] If the temperature difference between the pipe temperature and the ambient temperature exceeds the third threshold compared to the third reference value, and if the flow rate is still not measured by the flow meter 16, a microleak is detected.

[0089] Figure 4 A signal flow diagram of a third embodiment of the present invention is shown.

[0090] In step 40, flow meter 16 measures the flow rate of fluid through fluid pipe 12. In step 41, at least one of pipe temperature sensors 17a and 17b measures the pipe temperature. In step 42, ambient temperature sensor 18 measures the ambient temperature.

[0091] In step 43, it is determined whether flow meter 16 is not measuring the fluid flow rate through fluid conduit 12. If this is not the case, the method returns to step 40. If this is the case, the method proceeds to step 44.

[0092] In step 44, it is determined whether the flow meter 16 has not measured the fluid flow rate through the fluid conduit 12 within a defined time interval. If this is not the case, the method returns to step 40. If this is the case, the method proceeds to step 45.

[0093] In step 45, the temperature difference between the pipe temperature measured by the corresponding pipe temperature sensors 17a, 17b and the ambient temperature measured by the ambient temperature sensor 18 is calculated.

[0094] Then, in step 46, it is determined whether the temperature difference differs from the third reference value by more than a third threshold. If the temperature difference does not differ from the third reference value by more than the third threshold, no microleakage is detected in step 46. If the temperature difference differs from the third reference value by more than the third threshold, and if the fluid flow rate is still not measured by the flow meter 16, a microleakage is detected in step 47.

[0095] The third threshold for the temperature difference between the pipe temperature and the ambient temperature can be determined as follows: If no fluid flow rate is measured within a defined time interval, the temperature difference between the pipe temperature and the ambient temperature is calculated and stored. An average value is calculated based on the stored temperature difference. A first threshold is determined based on this average value. This average value can be multiplied by a coefficient to determine a third reference value.

[0096] The temperature difference between the pipe temperature and the ambient temperature can be calculated at each sampling moment of the sampling rate. However, the temperature difference may not be stored at each sampling moment of the sampling rate. The calculated temperature difference may be stored once after its calculation, for example, every 10, 20, 50, or 100 times. The calculated temperature difference may be stored in an annular buffer of the memory 15e of the microleak detection device 15. The annular buffer may have a defined buffer size. If the annular buffer is completely full, an average value may be calculated. If the annular buffer is not completely full, an average value may not be calculated. If the annular buffer is completely full, and if a newly calculated temperature difference between the pipe temperature and the ambient temperature is to be stored, the oldest stored temperature difference will be replaced by the newly calculated temperature difference, and the average value will be recalculated.

[0097] The calculated temperature difference can only be stored and used to calculate the average value if the absolute value of the difference between the calculated temperature difference and the previously calculated temperature difference or the absolute value of the difference between the calculated temperature difference and the average value of the previously stored temperature differences is below a threshold.

[0098] Figure 7 A timing diagram further illustrating a third embodiment of the present invention is shown. Figure 7 The fluid flow rate 70 as a function of time t is shown, and the temperature difference 71 between the pipe temperature and the ambient temperature is measured by one of the pipe temperature sensors 17a, 17b.

[0099] At time points t1, t3, and t5, the corresponding fluid flow rate 70 through fluid pipe 12 begins. At time points t2, t4, and t6, the corresponding fluid flow rate 70 through fluid pipe 12 stops by closing fluid valve 14. When no fluid flow rate is measured by flow meter 16 within a defined time interval after the fluid flow rate through fluid pipe 12 stops at time points t2, t4, and t6, a temperature difference 71 is determined. If the temperature difference 71 between the pipe temperature and the ambient temperature differs from a third reference value by more than a third threshold, and if no flow rate is measured by flow meter 16, a microleak 73 is detected.

[0100] exist Figure 7 In the calculation, the temperature differences V1 and V2 determined within the defined time interval after time points t2 and t4 do not differ from the third reference value by more than the third threshold. Therefore, no microleakage was detected. The temperature difference V3 determined within the defined time interval after time point t6 differs from the third reference value by more than the third threshold. Therefore, a microleakage 72 was detected. The third reference value corresponds to the average of the temperature differences V1 and V2 calculated within the defined time interval after time points t2 and t4.

[0101] The third embodiment can be used in combination with the first and / or second embodiments. Therefore, microleakage can be detected if the time gradient of the pipe temperature differs from the first reference value by more than a first threshold, or if the temperature difference between the pipe temperature and the ambient temperature differs from the third reference value by more than a third threshold.

[0102] In addition, microleakage can be detected if the temperature difference between the two pipe temperatures exceeds a second threshold compared to the second reference value, or if the temperature difference between the pipe temperature and the ambient temperature exceeds a third threshold compared to the third reference value.

[0103] This invention allows for the detection of microleakage at a rate of less than 1 liter per hour. Such microleakage flow rates are below the measurement resolution or measurement range of the flow meter 16.

[0104] List of reference numerals

[0105] 10 Fluid Flow System

[0106] 11 Buildings

[0107] 12 Fluid Pipelines

[0108] 13 Main water pipes

[0109] 14 Fluid valve

[0110] 15. Micro-leakage detection equipment

[0111] 15a interface

[0112] 15b interface

[0113] 15c interface

[0114] 15d processor

[0115] 15e memory

[0116] 16 Flow Meters

[0117] 17a Pipeline Temperature Sensor

[0118] 17b Pipeline temperature sensor

[0119] 18 Ambient temperature sensor

[0120] 20 steps

[0121] 21 steps

[0122] 22 steps

[0123] 23 steps

[0124] 24 steps

[0125] 25 steps

[0126] 26 steps

[0127] 27 steps

[0128] 30 steps

[0129] 31 steps

[0130] 32 steps

[0131] 33 steps

[0132] 34 steps

[0133] 35 steps

[0134] 36 steps

[0135] 37 steps

[0136] 38 steps

[0137] 40 steps

[0138] 41 steps

[0139] 42 steps

[0140] 43 steps

[0141] 44 steps

[0142] 45 steps

[0143] 46 steps

[0144] 47 steps

[0145] 48 steps

[0146] 50 Fluid velocity

[0147] 51 Pipeline temperature

[0148] 52 Time gradient

[0149] 53 Micro-leakage

[0150] 60 Fluid velocity

[0151] 61 Pipeline temperature

[0152] 62 Pipeline temperature

[0153] 63 Temperature difference

[0154] 64 Micro-leakage

[0155] 70 Fluid velocity

[0156] 71 Temperature difference

[0157] 72. Micro-leakage.

Claims

1. A method for detecting microleakage in a fluid system (10), said fluid system (10) having a fluid conduit (12) with a fluid valve (14), in, When the fluid valve (14) is closed, the fluid flow through the fluid pipe (12) is stopped, and When the fluid valve (14) is open, the fluid flow rate through the fluid pipe (12) is permitted. The method includes the following steps: The flow rate of the fluid passing through the fluid pipe (12) is measured by the flow meter (16). The pipe temperature of the fluid pipe (12) is measured by at least one pipe temperature sensor (17a, 17b). When the fluid flow rate is not measured by the flow meter (16), the micro-leakage detection is performed by analyzing the pipe temperature as follows: If no fluid flow is measured by the flow meter (16) after the fluid flow stops, the time gradient of the pipe temperature is calculated and stored. The average value is calculated based on the stored time gradient. The first threshold is determined based on the average value, and When the fluid flow through the fluid pipe (12) stops and no fluid flow is measured by the flow meter (16), the time gradient of the pipe temperature is calculated. If the calculated time gradient of the pipe temperature differs from the first reference value by more than the first threshold, and if no fluid flow is measured by the flow meter (16), a microleak is detected.

2. The method according to claim 1, characterized in that: When the fluid flow rate is measured by the flow meter (16) and when the fluid flow rate is not measured by the flow meter (16), the pipe temperature of the fluid pipe (12) is measured by the at least one pipe temperature sensor (17a, 17b). The measured fluid flow rate is analyzed for the microleak detection only when no fluid flow rate is measured by the flow meter (16).

3. The method according to claim 1, characterized in that: The pipe temperature of the fluid pipe (12) is measured by the at least one pipe temperature sensor (17a, 17b) and analyzed for the micro-leak detection only when the fluid flow rate is not measured by the flow meter (16).

4. The method according to claim 1, characterized in that... The calculated time gradient is stored and used to calculate the average only if the absolute value of the difference between the calculated time gradient and the previously calculated time gradient, or the absolute value of the difference between the calculated time gradient and the average value of the previously stored time gradients, is below a threshold.

5. The method according to claim 1, characterized in that, The average value is multiplied by a coefficient to determine the first reference value.

6. The method according to any one of claims 1 to 5, characterized by the following steps: The pipe temperature of the fluid pipe (12) is measured by a first pipe temperature sensor (17a) and a second pipe temperature sensor (17b) located at different positions on the fluid pipe (12). When no fluid flow rate is measured by the flow meter (16) within a defined time interval, the temperature difference between the pipe temperatures measured by the first pipe temperature sensor (17a) and the second pipe temperature sensor (17b) is calculated. If the temperature difference between the pipe temperatures exceeds a second threshold from the second reference value, and if no fluid flow is measured by the flow meter (16), a microleak is detected.

7. The method according to claim 6, characterized in that, The second reference value is determined as follows: If no fluid flow rate is measured within the defined time interval, the temperature difference between the pipe temperatures measured by the first pipe temperature sensor (17a) and the second pipe temperature sensor (17b) is calculated and stored. Calculate the average value based on the temperature difference of the storage. The second threshold is determined based on the average value.

8. The method according to claim 7, characterized in that, The average value is multiplied by a coefficient to determine the second reference value.

9. The method according to any one of claims 1 to 5, characterized by the following steps: The ambient temperature is measured by at least one ambient temperature sensor (18). When no fluid flow rate is measured by the flow meter (16) within a defined time interval, the temperature difference between the pipe temperature and the ambient temperature is calculated. If the temperature difference between the pipe temperature and the ambient temperature differs from the third reference value by more than a third threshold, and if the fluid flow rate is not measured by the flow meter (16), a microleak is detected.

10. The method according to claim 9, characterized in that... The third reference value for the temperature difference between the pipeline temperature and the ambient temperature is determined as follows: If no fluid flow rate is measured within a defined time interval, the temperature difference between the pipe temperature and the ambient temperature is calculated and stored. Calculate the average value based on the temperature difference of the storage. The third threshold is determined based on the average value.

11. The method according to claim 10, characterized in that... The calculated temperature difference is stored and used to calculate the average only if the absolute value of the difference between the calculated temperature difference and the previously calculated temperature difference, or the absolute value of the difference between the calculated temperature difference and the average value of the previously stored temperature differences, is below a threshold.

12. The method according to claim 10 or 11, characterized in that, The average value is multiplied by a coefficient to determine the third reference value.

13. A microleakage detection device (15) suitable for fluid systems, said microleakage detection device having: A first interface (15a) is configured to receive a signal from a flow meter (16) that measures the flow rate of fluid passing through a fluid conduit (12) of the fluid system. The second interface (15b) is configured to receive signals from at least one pipe temperature sensor (17a, 17b) that measures the pipe temperature of the fluid pipe (12). A processor (15d) configured to detect microleakage by analyzing the pipe temperature using the method according to any one of claims 1 to 12 when no fluid flow rate is measured by the flow meter (16).

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