A sliding type pipeline leakage detection and positioning device and detection and positioning method thereof

Abstract

The present invention belongs to the technical field of pipeline leakage detection and positioning, and specifically relates to a sliding pipeline leakage detection and positioning device and a detection and positioning method thereof, comprising: a flow supply and data processing module A, a pipeline installation detection module B, an air source, a plurality of transmission cables and a plurality of pressure hoses; the flow supply and data processing module A is connected to the pipeline installation detection module B through a transmission cable and a plurality of pressure hoses, and the air source is connected to the flow supply and data processing module A through a pressure hose.

Description

Technical Field

[0001] The invention belongs to the technical field of pipeline leakage detection and positioning, and in particular relates to a sliding pipeline leakage detection and positioning device and a detection and positioning method thereof. Background Art

[0002] During the production and operation of power plants, local leakage of plant pipelines is often encountered. Before the implementation of fault elimination, it is particularly important to find and locate the leakage point. Generally, there are many mature detection methods for locating leakage points in short-distance pipelines, such as positive pressure bubble method and helium detection sniffing gun method. However, for locating leakage points in long-distance pipelines, the above methods have disadvantages such as large workload and high probability of missed detection.

[0003] At present, there are few methods for locating leaks in long-distance buried pipelines in the power industry. The oil and gas transportation industry mainly pre-installs leak detection devices during the pipeline installation phase and requires regular weak current to conduct leak detection. Due to the high risk of live leak detection, it is not very suitable for leak detection in many pipelines in power plants.

[0004] Therefore, it is necessary to design a safe, reliable and convenient leakage detection and positioning device to solve the above technical problems. Summary of the invention

[0005] The purpose of the present invention is to design a sliding pipeline leak detection and positioning device and a detection and positioning method thereof, so as to solve the technical problems of existing leak detection methods, such as large workload, high probability of missed detection and high risk of live leak detection.

[0006] The technical solution of the present invention:

[0007] A sliding type pipeline leakage detection and positioning device comprises: a flow supply and data processing module A, a pipeline installation detection module B, an air source, a plurality of transmission cables and a plurality of pressure hoses; the flow supply and data processing module A is connected to the pipeline installation detection module B via the transmission cable and the plurality of pressure hoses, and the air source is connected to the flow supply and data processing module A via the pressure hose.

[0008] The flow supply and data processing module A includes: an air intake switch, a mode switching valve, a flow regulating valve, a flow transmitter, a bypass switch valve, a temperature sensor, a current / digital converter, and an industrial computer;

[0009] One end of the flow transmitter is connected to the 1 / 4 splitter through a transmission cable, the other end of the flow transmitter is connected to one end of the mode switching valve, and the other end of the mode switching valve is connected to the air intake switch; a temperature sensor is also arranged between the flow transmitter and the 1 / 4 splitter; the flow regulating valve and the bypass switch valve are arranged in parallel between the flow transmitter and the mode switching valve through a pressure-bearing hose; the temperature sensor and the flow transmitter are also respectively connected to the current / digital converter, and the current / digital converter is connected to the industrial computer through a transmission cable.

[0010] The pipeline installation detection module B comprises: a leak point measurement sleeve, a reference leak hole installation hole, a helium detector installation hole, a reference leak hole and a helium detector;

[0011] The leakage point measurement sleeve comprises: an upstream sealing fixing ring, a plurality of flow air inlets, an upstream sealing cover, a downstream bracket and a downstream fixing ring; the upstream sealing cover is arranged at one end of the leakage point measurement sleeve, and an upstream sealing fixing ring is arranged at the center of the outer surface of the upstream sealing cover; the plurality of flow air inlets are evenly arranged on the outer surface of the upstream sealing cover around the upstream sealing fixing ring;

[0012] The other end of the leakage point measurement sleeve is provided with a downstream bracket, and the downstream bracket is provided with a downstream fixing ring;

[0013] The reference leak hole mounting hole is arranged at the upstream sealing cover position close to the leak point measurement sleeve, and the reference leak hole is fixedly connected to the leak point measurement sleeve through the reference leak hole mounting hole; the helium detector mounting hole is arranged at the downstream bracket position close to the leak point measurement sleeve, and the helium detector is fixedly connected to the leak point measurement sleeve through the helium detector mounting hole.

[0014] The reference leak hole installation hole and the helium detector installation hole are arranged on the same side of the outer wall of the leak point measurement sleeve.

[0015] The 1 / 4 flow divider is connected to a plurality of flow inlets on the leak point measurement sleeve through a plurality of pressure-bearing hoses. The 1 / 4 flow divider is used to evenly divide the flow so that the flow in the detection sleeve is distributed as evenly as possible, thereby reducing airflow disturbance errors.

[0016] The helium detector is connected to the current / digital converter via a transmission cable.

[0017] The upstream sealing fixing ring is made of rubber, and the upstream sealing cover, the downstream bracket and the downstream fixing ring are all made of hard plastic or metal.

[0018] A detection and positioning method of the sliding type pipeline leak detection and positioning device as described above comprises the following steps:

[0019] Step 1: Fill the pipeline with helium

[0020] First, insert the leak point measurement sleeve into the inspected pipe section, isolate and seal the inspected pipe, and fill the inspected pipe with helium to make the pressure inside the pipe higher than the atmospheric pressure by more than 0.15MPa. Maintain the pressure for 1 hour and record the overall leakage rate of the pipeline.

[0021] Step 2: Installation

[0022] At the beginning of one end of the pipeline, use a pipe clamp to fasten the upstream sealing ring to the pipeline, and the contact surface between the upstream sealing ring and the pipeline should be as sealed as possible; connect the four pipes at the outlet of the 1 / 4 splitter to the flow inlet, and install the helium detector at the location of the helium detector installation hole; connect the gas source to the upstream pipeline interface of the air inlet switch, and connect the current / digital converter and the industrial computer to the power supply and run them respectively;

[0023] Step 3: Troubleshoot

[0024] Turn on the air inlet switch, adjust the mode switching valve to the troubleshooting mode, open the bypass switch valve, and observe the changes in the helium concentration curve on the computer. If there is no obvious change and it is close to the background value, it means that there is no leak in this section. Move the upstream sealing ring to the next section of the pipeline for troubleshooting;

[0025] Step 4: Positioning

[0026] If the helium concentration is found to have changed and is significantly higher than the background value during the investigation, the adjustment mode switching valve is switched to the positioning mode, the flow control valve is adjusted, the system flow is adjusted to V1, the leak rate is observed, and a standard leak with a similar leak rate is installed at the reference leak installation hole. After the air flow rate is stable and the helium mass spectrometer leak detector signal is stable, the flow control valve is adjusted to adjust the air flow rate to V2; the computer records the time when the helium concentration changes for the first time and the subsequent curve changes. The computer calculates the distance between the leak point and the reference leak based on the time t, air temperature T, pipe cross-sectional area S, sleeve flow rate V2, and correction coefficient K parameters at the two moments. The calculation formula is as follows: Formula (1):

[0027]

[0028] Beneficial effects of the present invention:

[0029] The present invention designs a sliding pipeline leak detection and positioning device and a detection and positioning method thereof. According to the industry's many years of helium leak detection experience and through multiple test bench simulation tests, a portable sliding pipeline leak detection and positioning device based on the helium detection method is designed. Without disassembling the pipeline, segmented leak investigation and positioning are implemented, which effectively improves the leak detection efficiency and safety, ensures that the location and leakage rate of the pipeline leak can be detected quickly and conveniently, and clarifies the direction and reduces the workload for subsequent internal pipe defect treatment.

[0030] The specific beneficial effects of the technology of the present invention are as follows:

[0031] (1) Based on the principle of correlation between the leakage rate of a leak hole and the gas flow rate, the invention provides a detection device for flexibly detecting and locating the position of a pipeline leak, and can simultaneously locate the position and leakage rate of multiple leaks;

[0032] (2) When the device is used, the inspected pipe section only needs to be filled with helium to maintain pressure, and no opening operation is required. It has low requirements on the conditions of the inspected pipeline and is particularly suitable for locating leaks in pipelines with complex structures and interfaces on site;

[0033] (3) Since the device can detect and locate pipeline leaks in sections, it is suitable for situations where the pipeline changes diameter or turns multiple times. As long as there is no change in diameter in the pipe section within the sleeve range, the sleeve structure is simple and the length can be determined according to the on-site conditions during processing;

[0034] (4) The design of the sliding sleeve makes leak detection flexible and convenient, and significantly improves the leak detection efficiency compared to the suction gun method;

[0035] (5) The leak point locating device uses helium and compressed air as the working medium. It is safe and reliable and can be used for leak detection in high-risk places such as flammable, explosive, and high-temperature places. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of the structure of a sliding pipeline leak detection and positioning device designed for the present invention;

[0037] Figure 2 It is a schematic diagram of the structure of the leakage point measuring sleeve in the leakage point detection and positioning device of the present invention;

[0038] Among them: 1. Inlet switch, 2. Mode switching valve, 3. Flow control valve, 4. Flow transmitter, 5. Bypass switch valve, 6. Temperature sensor, 7. 1 / 4 diverter, 8. Leakage point measurement sleeve, 9. Upstream sealing fixing ring, 10. Flow inlet, 11. Upstream sealing cover, 12. Reference leak hole installation hole, 13. Helium detector installation hole, 14. Downstream bracket, 15. Downstream fixing ring, 16. Reference leak hole, 17. Fixed helium detector with display, 18. Current / digital converter, 19. Industrial computer; DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0040] The device of the present invention is composed of a flow supply and data processing module A and a pipeline installation detection module B. After the pipeline under inspection is filled with helium at a certain pressure, the change in sleeve flow will cause a corresponding change in the helium concentration downstream of the leak point. The device of the present invention uses this principle to identify the leak point and locate the distance between the leak point and the helium detector.

[0041] In addition, the portable sliding pipeline leak detection and positioning device and detection method designed by the present invention can implement segmented leak investigation and positioning without disassembling the pipeline, effectively improving the leak detection efficiency and safety, ensuring that the location and leakage rate of pipeline leaks can be detected quickly and conveniently, clarifying the direction and reducing the workload for subsequent internal pipe defect treatment work.

[0042] A sliding type pipeline leakage detection and positioning device designed by the present invention specifically includes: a flow supply and data processing module A, a pipeline installation detection module B, an air source, a plurality of transmission cables and a plurality of pressure hoses; the flow supply and data processing module A is connected to the pipeline installation detection module B through a transmission cable and a plurality of pressure hoses, and the air source is connected to the flow supply and data processing module A through a pressure hose.

[0043] The flow supply and data processing module A includes: an air intake switch 1, a mode switching valve 2, a flow regulating valve 3, a flow transmitter 4, a bypass switch valve 5, a temperature sensor 6, a current / digital converter 18, and an industrial computer 19;

[0044] One end of the flow transmitter 4 is connected to the 1 / 4 diverter 7 through a transmission cable, the other end of the flow transmitter 4 is connected to one end of the mode switching valve 2, and the other end of the mode switching valve 2 is connected to the air intake switch 1; a temperature sensor 6 is also arranged between the flow transmitter 4 and the 1 / 4 diverter 7; the flow regulating valve 3 and the bypass switch valve 5 are arranged in parallel between the flow transmitter 4 and the mode switching valve 2 through a pressure hose; the temperature sensor 6 and the flow transmitter 4 are also respectively connected to the current / digital converter 18, and the current / digital converter 18 is connected to the industrial computer 19 through a transmission cable.

[0045] The pipeline installation detection module B comprises: a leak point measurement sleeve 8, a reference leak hole installation hole 12, a helium detector installation hole 13, a reference leak hole 16 and a helium detector 17;

[0046] The leakage point measurement sleeve 8 comprises: an upstream sealing fixing ring 9, a plurality of flow air inlets 10, an upstream sealing cover 11, a downstream bracket 14 and a downstream fixing ring 15; the upstream sealing cover 11 is arranged at one end of the leakage point measurement sleeve 8, and the upstream sealing fixing ring 9 is arranged at the center of the outer surface of the upstream sealing cover 11; the plurality of flow air inlets 10 are evenly arranged on the outer surface of the upstream sealing cover 11 around the upstream sealing fixing ring 9;

[0047] The other end of the leakage point measuring sleeve 8 is provided with a downstream bracket 14, and the downstream bracket 14 is provided with a downstream fixing ring 15;

[0048] The reference leak hole mounting hole 12 is arranged at the upstream sealing cover 11 position close to the leak point measurement sleeve 8, and the reference leak hole 16 is fixedly connected to the leak point measurement sleeve 8 through the reference leak hole mounting hole 12; the helium detector mounting hole 13 is arranged at the downstream bracket 14 position close to the leak point measurement sleeve 8, and the helium detector 17 is fixedly connected to the leak point measurement sleeve 8 through the helium detector mounting hole 13.

[0049] The reference leak hole installation hole 12 and the helium detector installation hole 13 are arranged on the same side of the outer wall of the leak point measurement sleeve 8 .

[0050] The 1 / 4 flow divider 7 is connected to a plurality of flow inlets 10 on the leakage point measurement sleeve 8 through a plurality of pressure-bearing hoses. The 1 / 4 flow divider 7 is used to evenly divide the flow so that the flow in the detection sleeve is distributed as evenly as possible to reduce the airflow disturbance error.

[0051] The helium detector 17 is connected to a current / digital converter 18 via a transmission cable.

[0052] The upstream sealing fixing ring 9 is made of rubber, and the upstream sealing cover 11, the downstream bracket 14 and the downstream fixing ring 15 are all made of hard plastic or metal.

[0053] The flow regulating valve 3 is used to control and adjust the flow, and the mode switching valve 2 is used to switch the system to the positioning mode or the troubleshooting mode;

[0054] The flow transmitter 4 and the temperature sensor 6 are used to collect data, and the current / digital converter 18 converts the collected temperature, helium concentration, flow and other signals into digital signals and transmits them to the collection computer 19. The collection computer 19 is used to count and display the flow, temperature, helium concentration, time and other data information, and finally calculate the distance between the leak point and the detector.

[0055] The leakage point measurement sleeve 8 is used to provide a regular flow channel for the periphery of the pipeline. The length of the sleeve is adjusted according to needs. The longer the sleeve, the higher the accuracy.

[0056] During the inspection, the upstream sealing fixing ring 9 is clamped on the outer wall of the inspected pipeline through the pipe clamp.

[0057] The reference leak 16 is used to verify the accuracy of the device and to correct the system error;

[0058] The fixed helium detector 17 with display is used to measure and detect the helium concentration in the sleeve, and transmit the concentration signal to the current / digital converter 18 through a cable.

[0059] A detection and positioning method of the sliding type pipeline leak detection and positioning device as described above comprises the following steps:

[0060] Step 1: Fill the pipeline with helium

[0061] First, insert the leak point measurement sleeve into the inspected pipe section, isolate and seal the inspected pipe, and fill the inspected pipe with helium to make the pressure in the pipe higher than the atmospheric pressure by more than 0.15MPa. Maintain the pressure for 1 hour and record the overall leakage rate of the pipe.

[0062] Step 2: Installation

[0063] At the beginning of one end of the pipeline, use a pipe clamp to fasten the upstream sealing ring 9 to the pipeline, and the contact surface between the upstream sealing ring 9 and the pipeline is as sealed as possible; connect the four pipelines at the outlet of the 1 / 4 splitter 7 to the flow inlet 10, and install the helium detector at the position of the helium detector installation hole 13; connect the gas source to the upstream pipeline interface of the air inlet switch 1, and connect the current / digital converter 18 and the industrial computer 19 to the power supply and run them respectively;

[0064] Step 3: Troubleshoot

[0065] Open the air inlet switch 1, adjust the mode switching valve 2 to the troubleshooting mode, open the bypass switch valve 5, and observe the changes in the helium concentration curve on the computer. If there is no obvious change and it is close to the background value, it means that there is no leak in this section. Move the upstream sealing fixing ring 9 to the next section of the pipeline for troubleshooting;

[0066] Step 4: Positioning

[0067] If the helium concentration is found to have changed and is significantly higher than the background value during the investigation, the adjustment mode switching valve 2 is switched to the positioning mode, the flow control valve 3 is adjusted, the system flow is adjusted to V1, the leak rate is observed, and a standard leak with a similar leak rate is installed in the reference leak installation hole 12. After the air flow rate is stable and the helium mass spectrometer leak detector signal is stable, the flow control valve 3 is adjusted to adjust the air flow rate to V2; the computer records the time when the helium concentration changes for the first time and the subsequent curve changes. The computer calculates the distance between the leak point and the reference leak based on the time t, air temperature T, pipeline cross-sectional area S, sleeve flow rate V2, and correction coefficient K parameters at the two moments. The calculation formula is as follows:

[0068]

[0069] Test verification

[0070] The method adopted by this device has been used in the laboratory to carry out nearly a thousand "pipeline leak simulation leak location tests" over a period of 6 months. The test results show that the leak location can be fully detected using this device, and the error can be controlled within 0.5 meters when supplemented by relevant correction calculation methods.

[0071] The positioning method used in the double-walled hydrogen pipe leak detection of a nuclear power plant is basically consistent with the principle of this device. In the positioning of the leak point of a 1050-meter pipeline, the deviation between the positioning position and the actual leak point was less than 1%, which successfully reduced the time for eliminating the defect and the workload of replacing the defective pipeline.

[0072] Effect evaluation

[0073] The present invention can not only safely, accurately and flexibly check for leaks in long-distance pipelines, but also accurately locate the leaks. Compared with the traditional suction gun method, it significantly improves the leak detection efficiency and reduces the risk of missed detection. Especially in the outdoor long-distance pipeline leak detection, it can completely replace the suction gun method to locate the leak. This device uses helium and air as the inspection medium and has a relatively simple structure. It has the characteristics of high safety, strong flexibility and relatively simple implementation. When the device is used, the object to be inspected does not need to be heated or powered on, and can be used in flammable and explosive environments. It has great engineering application value in the future.

[0074] The present invention is described in detail above with reference to the accompanying drawings and embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present invention. Any content not described in detail in the present invention can adopt the existing technology.

Claims

1. A sliding pipeline leak detection and positioning device, characterized in that: include: Flow supply and data processing module A, pipeline installation detection module B, gas source, several transmission cables and several pressure hoses; The flow supply and data processing module A is connected to the pipeline installation detection module B via a transmission cable and a plurality of pressure hoses, and the gas source is connected to the flow supply and data processing module A via a pressure hose; The flow supply and data processing module A comprises: an air intake switch (1), a mode switching valve (2), a flow regulating valve (3), a flow transmitter (4), a bypass switch valve (5), a temperature sensor (6), a current / digital converter (18), and an industrial computer (19); One end of the flow transmitter (4) is connected to the 1 / 4 flow divider (7) through a pressure-bearing hose, the other end of the flow transmitter (4) is connected to one end of the mode switching valve (2), and the other end of the mode switching valve (2) is connected to the air intake switch (1); a temperature sensor (6) is also arranged between the flow transmitter (4) and the 1 / 4 flow divider (7); the flow regulating valve (3) and the bypass switch valve (5) are arranged in parallel between the flow transmitter (4) and the mode switching valve (2) through a pressure-bearing hose; the temperature sensor (6) and the flow transmitter (4) are also respectively connected to a current / digital converter (18), and the current / digital converter (18) is connected to an industrial computer (19) through a transmission cable; The pipeline installation detection module B comprises: a leak point measurement sleeve (8), a reference leak hole installation hole (12), a helium detector installation hole (13), a reference leak hole (16) and a helium detector (17); The leakage point measurement sleeve (8) comprises: an upstream sealing fixing ring (9), a plurality of flow air inlets (10), an upstream sealing cover (11), a downstream bracket (14) and a downstream fixing ring (15); the upstream sealing cover (11) is arranged at one end of the leakage point measurement sleeve (8), and the upstream sealing fixing ring (9) is arranged at the center of the outer surface of the upstream sealing cover (11); the plurality of flow air inlets (10) are evenly arranged on the outer surface of the upstream sealing cover (11) around the upstream sealing fixing ring (9); A downstream bracket (14) is provided at the other end of the leakage point measurement sleeve (8), and a downstream fixing ring (15) is provided on the downstream bracket (14); The reference leak hole mounting hole (12) is arranged at a position of the upstream sealing cover (11) close to the leak point measurement sleeve (8), and the reference leak hole (16) is fixedly connected to the leak point measurement sleeve (8) through the reference leak hole mounting hole (12); the helium detector mounting hole (13) is arranged at a position of the downstream bracket (14) close to the leak point measurement sleeve (8), and the helium detector (17) is fixedly connected to the leak point measurement sleeve (8) through the helium detector mounting hole (13); The 1 / 4 flow divider (7) is connected to a plurality of flow inlets (10) on the leak point measurement sleeve (8) via a plurality of pressure-bearing hoses. The 1 / 4 flow divider (7) is used to evenly divide the flow so that the flow in the detection sleeve is distributed as evenly as possible, thereby reducing air flow disturbance errors. The leak point measurement sleeve (8) is used to provide a regular flow channel for the periphery of the pipeline. The length of the sleeve is adjusted according to needs. The longer the sleeve, the higher the accuracy.

2. A sliding type pipeline leak detection and positioning device as claimed in claim 1, characterized in that: The reference leak hole mounting hole (12) and the helium detector mounting hole (13) are arranged on the same side of the outer wall of the leak point measurement sleeve (8).

3. A sliding type pipeline leak detection and positioning device as claimed in claim 2, characterized in that: The helium detector (17) is connected to the current / digital converter (18) via a transmission cable.

4. A sliding type pipeline leak detection and positioning device as claimed in claim 3, characterized in that: The upstream sealing fixing ring (9) is made of rubber, and the upstream sealing cover (11), the downstream bracket (14), and the downstream fixing ring (15) are all made of hard plastic or metal.

5. A detection and positioning method of the sliding pipeline leakage detection and positioning device according to any one of claims 1 to 4, characterized in that: The steps include: Step 1: Fill the pipeline with helium First, insert the leak point measurement sleeve (8) into the inspected pipe section, isolate and seal the inspected pipe, and fill the inspected pipe with helium to make the pressure inside the pipe higher than the atmospheric pressure by more than 0.15 MPa. Maintain the pressure for 1 hour and record the overall leakage rate of the pipe. Step 2: Installation At the beginning of one end of the pipeline, the upstream sealing ring (9) is fastened to the pipeline using a pipe clamp, and the contact surface between the upstream sealing ring (9) and the pipeline is as sealed as possible; the four pipelines at the outlet of the 1 / 4 splitter (7) are connected to the flow inlet (10), and the helium detector is installed at the position of the helium detector installation hole (13); the gas source is connected to the upstream pipeline interface of the air inlet switch (1), and the current / digital converter (18) and the industrial computer (19) are respectively connected to the power supply and run; Step 3: Troubleshoot Open the air inlet switch (1), adjust the mode switching valve (2) to the troubleshooting mode, open the bypass switch valve (5), and observe the changes in the helium concentration curve on the computer. If there is no obvious change and it is close to the background value, it means that there is no leak in this section. Move the upstream sealing ring (9) to the next section of the pipeline for troubleshooting; Step 4: Positioning If it is found during the investigation that the helium concentration changes and is significantly higher than the background value, adjust the mode switching valve (2) to the positioning mode, adjust the flow control valve (3), adjust the system flow to V1, observe the leak rate, and install a standard leak with a similar leak rate in the reference leak installation hole (12). After the air flow rate is stable and the helium mass spectrometer leak detector signal is stable, adjust the flow control valve (3) to adjust the air flow rate to V2; record the time when the helium concentration changes for the first time and the subsequent curve changes on the computer. The computer calculates the distance between the leak point and the reference leak based on the time t, air temperature T, pipeline cross-sectional area S, sleeve flow rate V2, and correction coefficient K parameters at the two times. The calculation formula is as follows: Formula (1): ………………………………（1）。

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