Large-diameter GRP pipeline pressure test method

Abstract

The invention relates to the field of GRP pipeline pressure testing, in particular to a large-diameter GRP pipeline pressure testing method, which comprises the following steps of S1, performing preparation work before pressure testing; s2, a pre-hydrostatic test: carrying out segmented pressurization on the pipeline to be subjected to pressure test; s2, checking whether the pipeline to be subjected to pressure test leaks or not, if leakage occurs, repeating S2 after overhauling, and if leakage does not occur, continuing pressurizing to test pressure; s3, main hydrostatic test: after reaching the test pressure, maintaining the pressure for 30-35 minutes, reducing the pressure to the working pressure if the pressure drop is less than or equal to 0.02 MPa during the pressure maintaining period, and maintaining the pressure for 30-35 minutes; checking whether the pipeline to be subjected to pressure test leaks or not, and if yes, repeating the steps S2-S3 after overhauling; if no leakage exists, the main hydrostatic test is ended; and S4, discharging water and releasing pressure, and dismounting the temporary pressure test system. According to the pressure testing method, the characteristics of the material of the GRP pipeline are comprehensively considered, and the problems that in a traditional pressure testing method, the GRP pipeline is prone to being damaged due to too fast pressure loading and the construction period is prone to being affected due to too slow pressure loading are effectively solved in a segmented pressurization and multi-stage pressure maintaining mode.

Description

Technical Field

[0001] The invention relates to the field of GRP pipeline pressure testing, and in particular to a large-diameter GRP pipeline pressure testing method. Background Art

[0002] GRP pipes (GRP pipes also known as polyester FRP pipes) are widely used in coastal projects due to their excellent corrosion resistance, high strength, and light weight. However, these advantages are also accompanied by challenges in installation and testing.

[0003] At present, the water pressure test of GRP pipes still uses the pressure test method of pipes made of conventional materials (such as aluminum-plastic composite pipes, hot-dip galvanized steel pipes, etc.). Specifically, the traditional pipeline water pressure test method has the following steps: First, the staff needs to use blind plates to tightly seal both ends of the pipe section to be tested. Then, a large amount of fresh water is injected into the entire GRP pipe until the pipe is completely filled. Next, a booster pump is used to continuously apply pressure to the pipe. After confirming that there is no leakage, the water is discharged and the entire test process is completed.

[0004] However, the material of GRP pipes is generally a composite of glass fiber and resin, which has a certain degree of brittleness. In addition, the diameter of large-diameter GRP pipes exceeds 3 meters. If the traditional pipe pressure test method is used, the brittle characteristics of the GRP pipe material itself are not taken into account. If the pressure is loaded too quickly during the pressure test, the stress inside the pipe will increase rapidly and exceed the bearing capacity of the material, which may easily lead to the risk of stratification and cracking of the GRP pipe during the pressure test. If the pressure is loaded too slowly, there is a risk of affecting construction efficiency, extending the construction period, and increasing construction costs. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the traditional pipeline pressure testing method that if the pressure is loaded too quickly, it will easily cause damage to the GRP pipeline, and if the pressure is loaded too slowly, it will affect the construction period, and provide a large-diameter GRP pipeline pressure testing method.

[0006] In a first aspect, the present invention provides a large diameter GRP pipe pressure testing method, comprising the following steps:

[0007] S1: Carry out preparatory work before pressure test to ensure that the pipeline system is complete and the equipment required for pressure test has been brought in and can operate normally;

[0008] S2: Pre-hydraulic pressure test: Pressurize the pipeline to be tested in sections. When the pressure reaches 0.2 times the test pressure, stop pressurizing and keep the pressure for 10-15 minutes. Continue to pressurize to 0.5 times the test pressure and stop pressurizing for 10-15 minutes. Continue to pressurize to 0.8 times the test pressure and stop pressurizing for 10-15 minutes. Check whether the pipeline to be tested is leaking. If there is a leak, repeat S2 after repair. If there is no leak, continue to pressurize to the test pressure.

[0009] S3: Main water pressure test: After reaching the test pressure, maintain the pressure for 30-35 minutes. If the pressure drop is ≤0.02MPa during the pressure maintenance period, reduce the pressure to the working pressure and maintain the pressure for 30-35 minutes; check whether the pipeline to be tested is leaking. If there is a leak, repeat S2-S3 after repair; if there is no leak, the main water pressure test is over;

[0010] S4: Release water, release pressure and dismantle the temporary pressure test system.

[0011] The GRP pipeline pressure testing method provided by the present invention first performs a pre-hydraulic pressure test: the pressure is finally increased to the test pressure according to 0.2 times the test pressure, 0.5 times the test pressure, and 0.8 times the test pressure, and the pressure is gradually increased to avoid stress concentration caused by sudden pressure changes, thereby reducing the risk of sudden rupture of the GRP pipeline. After each level of pressurization is in place, the pressure is fully maintained, and the sealing performance of the pipeline is gradually tested. By maintaining the pressure in the low-pressure stage, slight leaks at pipeline joints, welds and other locations can be discovered in advance. These leaks may expand under high pressure and lead to serious consequences, thereby improving the reliability of the detection; after the pre-hydraulic pressure test is completed, the main water pressure test is performed: the pressure is maintained for a long time at the two key nodes of the test pressure and the working pressure, so as to fully verify the pressure bearing capacity of the pipeline and ensure its safe operation. Under the premise of ensuring safety, through the pre-hydraulic pressure test and the main water pressure test: the pressurization time is reasonably arranged to improve work efficiency.

[0012] The GRP pipe pressure testing method provided by the present invention comprehensively considers the characteristics of the GRP pipe material itself, and effectively solves the problems in the traditional pressure testing method that too fast pressure loading can easily cause damage to the GRP pipe, and too slow pressure loading can easily affect the construction period by means of segmented pressurization and multi-stage pressure maintenance.

[0013] Preferably, S1 comprises the following steps:

[0014] S11: Calibrate the pressure test instrument and build a temporary pressure test system;

[0015] The temporary pressure test system includes blind plates fixedly connected to both ends of the pressure test pipeline; a drainage pipe connected to the lower end of the pressure test pipeline, on which a drainage valve is provided; an inlet pipe connected to the lower end of the pressure test pipeline, on which a pressure gauge and a water inlet valve are provided; an exhaust pipe installed at the upper end of the pressure test pipeline, on which a pressure gauge and an exhaust valve are provided;

[0016] S12: Close the drain valve, and inject water into the pressure test pipe through the water inlet pipe. Open the exhaust valve before injecting water. When the exhaust pipe is continuously flowing out water without bubbles, close the exhaust valve.

[0017] S13: Static soaking. Before the start of the pre-hydraulic pressure test, soak the test pipe for at least 24 hours to observe whether the liquid level drops. If leakage is found, repeat S12-S13 after inspection. If there is no leakage, proceed to the next step.

[0018] With this setting, the calibration of the pressure test instrument ensures the accuracy of pressure measurement and provides reliable data support for subsequent pressure tests. After the temporary pressure test system is built, water is injected into the pipe to be tested. The water inlet pipe is located at the low end of the pipe to be tested, and the exhaust pipe is located at the high end of the pipe to be tested. Water is injected from bottom to top into the pipe to be tested, which facilitates the exhaust of air in the pipe to be tested. When water flows out of the exhaust pipe continuously without bubbles, it indicates that the pipe to be tested is full of water, which can prevent gas from affecting the pressure test results.

[0019] Before the start of the pre-hydraulic pressure test, the test pipe should be fully immersed in a static state to help detect some small leaks that are difficult to find in the initial stage of pressurization. At the same time, soaking can allow the pipe to fully absorb water, avoiding the accuracy of the pressure data being affected by water absorption during the pressure test.

[0020] Preferably, in S11, the pressure test instrument is calibrated, including the pressure gauge, the pressure gauge has an accuracy of 1.5 and a maximum range of 2 MPa.

[0021] Further optimization of the range and accuracy of the pressure gauge can further improve the pressure test accuracy. If a pressure gauge with too small a range is selected, the range may be exceeded during the high-pressure test, resulting in inaccurate measurement results or even damage to the instrument.

[0022] Preferably, in S12, water is injected into the pipeline to be pressure tested through the water inlet pipe, and the injection speed is controlled between 0.6 m / s and 1.8 m / s.

[0023] When the fluid flows in the pipeline, if the valve is suddenly closed or the pump stops working, the kinetic energy of the fluid will be converted into pressure energy, resulting in water hammer, which will cause the pressure in the pipeline to rise sharply and may even damage the pipeline. It is preferred that the water injection speed be controlled between 0.6 m / s and 1.8 m / s, which can effectively reduce the probability of water hammer. Considering the characteristics of the GRP pipe material itself, the appropriate water injection speed can avoid excessive local pressure in the pipeline and reduce the risk of pipeline rupture during the pressure test.

[0024] Preferably, the temporary pressure test system in S11 further includes a manifold, one end of the water inlet pipe is connected to the pressure pump through the manifold, and the other end of the water inlet pipe is connected to the lower end of the pipeline to be pressure tested.

[0025] By adding a manifold between the pressure pump and the water inlet pipe, the manifold can be connected to other pipelines or pressure test instruments in addition to the pipeline to be tested, which is convenient for pressure testing and makes the temporary pressure test system more flexible, convenient and reliable. It not only improves the operating efficiency of the system, but also leaves room for future expansion.

[0026] Preferably, the manifold is installed with a pressure safety valve, and the safety limit of the pressure safety valve is 1.1 times the test pressure.

[0027] With this setting, when the system pressure exceeds the safety limit, the pressure safety valve will automatically open to release excess pressure, effectively preventing accidents such as system explosion due to overpressure. Setting the safety limit of the pressure safety valve to 1.1 times the test pressure can avoid some unforeseen factors during the test, such as pressure increase due to temperature. Setting a higher safety limit can provide a greater safety margin for the system.

[0028] Preferably, when S2 performs the pre-hydraulic pressure test, displacement monitoring points are set at both ends of the pipeline to be pressure tested to observe the displacement of the pipeline to be pressure tested in real time.

[0029] Setting displacement monitoring points in the pre-hydraulic pressure test can effectively monitor the deformation of the pipeline, providing an important basis for evaluating the bearing capacity of the pipeline, discovering potential defects, verifying the calculation model, etc., thereby improving the reliability of the test and ensuring the safety of the project.

[0030] Preferably, when S3 performs the main water pressure test, after reaching the test pressure, the pressure is maintained for 30-35 minutes. If there is a pressure drop during the pressure maintenance period, water is injected to supplement the pressure, but the pressure is not higher than the test pressure.

[0031] With this setting, the temperature environment may cause pressure fluctuations. In this case, the reliability of the pressure test can be ensured by injecting water to supplement the pressure. However, the pressure after supplementation should not be higher than the test pressure to avoid overpressure caused by temperature changes that may damage the GRP pipeline.

[0032] Preferably, when the pipeline to be pressure tested is pressurized in sections, the pressurization speed does not exceed 2 bar per minute.

[0033] Setting the pressurization speed of the segmented pressurization to no more than 2 bar per minute is a relatively safe pressurization speed. This pressurization speed can make the various parts of the pipeline bear the force evenly, avoid excessive local stress concentration, and thus reduce the risk of pipeline bursting; effectively mitigate the water hammer effect and protect the pipeline and connecting equipment.

[0034] Preferably, the test pressure is 1.5 times the working pressure of the pipeline to be tested.

[0035] The test pressure is set to 1.5 times the working pressure, taking into account the characteristics of the GRP pipe material itself. The test pressure is not too low, which will cause defects in the GRP pipe, such as cracks and pores, to not be tested, affecting the pressure test effect; nor is the test pressure too high, which will cause the risk of pipeline damage. 1.5 times the working pressure simulates extreme working conditions such as water hammer and temperature changes to a certain extent, and can more comprehensively evaluate the pressure resistance of the pipeline.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The GRP pipeline pressure test method provided by the present invention first conducts a preliminary water pressure test: the pressure is increased to 0.2 times the test pressure, 0.5 times the test pressure, and 0.8 times the test pressure, and finally pressurized to the test pressure, and the pressure is increased step by step to avoid stress concentration caused by sudden pressure changes, and reduce the risk of sudden rupture of the GRP pipeline. After each level of pressurization is in place, the pressure is fully maintained, and the sealing performance of the pipeline is gradually tested. By maintaining the pressure in the low-pressure stage, minor leaks in the pipeline joints, welds and other locations can be discovered in advance. These leaks may expand under high pressure and lead to serious consequences, thereby improving the reliability of the detection;

[0038] 2. The GRP pipeline pressure test method provided by the present invention performs a main water pressure test after the pre-hydraulic pressure test: the pressure is maintained for a long time at the two key nodes of the test pressure and the working pressure, which can fully verify the pressure bearing capacity of the pipeline and ensure its safe operation. Under the premise of ensuring safety, the pre-hydraulic pressure test and the main water pressure test are carried out: the pressurization time is reasonably arranged to improve work efficiency;

[0039] 3. The GRP pipe pressure testing method provided by the present invention comprehensively considers the characteristics of the GRP pipe material itself, and effectively solves the problem in the traditional pressure testing method that pressure loading too quickly may easily cause damage to the GRP pipe, and pressure loading too slowly may easily affect the construction period, by means of segmented pressurization and multi-stage pressure maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a flow chart of the GRP pipeline pressure testing method provided by the present invention.

[0041] Figure 2 Schematic diagram of GRP pipeline pressure test.

[0042] Figure 3 This is the pressure curve change diagram during GRP pipeline pressure test.

[0043] Markings in the figure:

[0044] 1-blind plate, 2-drain pipe, 21-drain valve, 3-water inlet pipe, 31-water inlet valve, 4-pressure gauge, 5-exhaust pipe, 51-exhaust valve, 6-manifold, 7-pressure pump, 8-pressure safety valve, 100-pipeline to be pressure tested. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0046] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all based on the expression of the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0047] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding devices / components / elements are within the error / deviation range, they can still achieve their functions in the scheme of the present invention.

[0048] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0049] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0050] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0051] Example 1

[0052] At present, traditional pressure testing methods are mostly for pipes made of conventional materials (cast iron pipes, polyvinyl chloride (PVC) pipes, aluminum-plastic composite pipes, hot-dip galvanized steel pipes). During the pressure test, the pressure increase or decrease rate is too fast, which can easily cause the GRP pipe to rupture or delaminate. Damaging the GRP pipe during the pressure test not only increases the construction cost, but also slows down the construction period. Figure 1 As shown, this embodiment provides a large diameter GRP pipe pressure testing method, comprising the following steps:

[0053] S1: Carry out preparatory work before pressure test to ensure that the pipeline system is complete and the equipment required for pressure test has been brought in and can operate normally;

[0054] Specifically, S1 includes the following steps:

[0055] S11: Calibrate the pressure test instrument and build a temporary pressure test system;

[0056] In this field, all pipelines or part of pipelines with the same test pressure and test method in one or more subsystems are regarded as a pressure test unit, which is called a pressure test package.

[0057] Therefore, a temporary pressure test system in a pressure test package is Figure 2 As shown, it can include blind plates 1 fixedly connected to both ends of the pipeline 100 to be pressure tested. The thickness of the blind plate 1 can be 25mm-30mm. Preferably, the blind plate 1 can be made of A36 steel with a thickness of 30mm. The appropriate thickness of the blind plate 1 enables it to withstand the high pressure impact generated during the pipeline pressure test, reduce the risk of failure caused by deformation or rupture of the thin plate, and ensure the safety and reliability of the pressure test process;

[0058] The lower end of the pipeline 100 to be tested (eg Figure 2 The left end of the pressure test pipeline 100 shown in the figure is connected to a drain pipe 2, and the drain pipe 2 can use a DN100mm seamless steel pipe; a drain valve 21 is provided on the drain pipe 2, and the drain valve 21 can specifically be a 3.0MPa ball valve;

[0059] The water inlet pipe 3 connected to the lower end of the pipeline 100 to be pressure tested can be a DN100mm seamless steel pipe; a pressure gauge 4 and a water inlet valve 31 are arranged on the water inlet pipe 3, the pressure gauge 4 can be a spring pressure gauge, and the water inlet valve 31 can be a 3.0MPa ball valve;

[0060] Set at the high end of the pipeline 100 to be tested (for example Figure 2 The exhaust pipe 5 is at the right end of the pipeline 100 to be pressure tested as shown. The exhaust pipe 5 can use a DN50mm seamless steel pipe. A pressure gauge 4 and an exhaust valve 51 are provided on the exhaust pipe 5. The exhaust valve 51 can use a 3.0MPa ball valve.

[0061] All pressure test instruments in the same pressure test package need to be calibrated, including the pressure gauge 4. The pressure gauge 4 has a precision of 1.5 and a maximum range of 2MPa. Further optimization of the range and accuracy of the pressure gauge 4 can further improve the pressure test accuracy. If a pressure gauge 4 with a too small range is selected, it may exceed the range during the high-pressure test, resulting in inaccurate measurement results or even damage to the instrument.

[0062] S12: Close the drain valve 21 and inject water into the pipeline 100 to be pressure tested through the water inlet pipe 3. The water injected into the pipeline 100 to be pressure tested is fresh water, and the injection speed is controlled between 0.6 m / s and 1.8 m / s.

[0063] When the fluid flows in the pipeline, if the valve is suddenly closed or the pump stops working, the kinetic energy of the fluid will be converted into pressure energy, resulting in water hammer, which will cause the pressure in the pipeline to rise sharply and may even damage the pipeline. It is preferred that the water injection speed be controlled between 0.6 m / s and 1.8 m / s, which can effectively reduce the probability of water hammer. Considering the characteristics of the GRP pipe material itself, the appropriate water injection speed can avoid excessive local pressure in the pipeline and reduce the risk of pipeline rupture during the pressure test.

[0064] Open the exhaust valve 51 before water injection. When water flows out of the exhaust pipe 5 continuously without bubbles, it means that the air in the pressure test pipeline 100 has been exhausted, and the exhaust valve 51 is closed.

[0065] S13: Static soaking. Before the start of the pre-hydraulic pressure test, soak the pressure test pipe 100 for at least 24 hours. Observe whether the liquid level drops through the water injection hole. If leakage is found, repeat S12-S13 after repair. If there is no leakage, proceed to the next step. At the same time, conduct a comprehensive inspection of each valve connection point of the pressure test pipe 100 that has not been backfilled. If obvious water seepage is found, the test should be interrupted immediately and the water seepage point should be checked and repaired.

[0066] The calibration of the pressure test instrument ensures the accuracy of pressure measurement and provides reliable data support for subsequent pressure tests. After the temporary pressure test system is built, water is injected into the pipeline 100 to be pressure tested. The water inlet pipe 3 is located at the lower end of the pipeline 100 to be pressure tested, and the exhaust pipe 5 is located at the high end of the pipeline 100 to be pressure tested. Water is injected into the pipeline from bottom to top to facilitate the exhaust of the air in the pipeline 100 to be pressure tested. When water flows out of the exhaust pipe 5 continuously without bubbles, it means that the pipeline 100 to be pressure tested is full of water, which can prevent gas from affecting the pressure test results.

[0067] Before the start of the pre-hydraulic pressure test, the pressure test pipe 100 is fully immersed in a static state, which is helpful to detect some small leaks that are difficult to find in the initial stage of pressurization; at the same time, through immersion, the pipe can fully absorb water, avoiding the accuracy of pressure data affected by water absorption during the pressure test.

[0068] S2: Pre-hydraulic pressure test: Figure 3 As shown, the pipeline 100 to be tested is pressurized in sections. Figure 3 Where Tp is Testing Pressure. For example, the working pressure of the pipeline 100 to be pressure tested is 5 bar. In this embodiment, the test pressure is set to 1.5 times the design pressure or working pressure, for example, 7.5 bar. The pressurization speed does not exceed 2 bar per minute during the pre-hydraulic pressure test. Setting the pressurization speed of the segmented pressurization to no more than 2 bar per minute is a relatively safe pressurization speed. This pressurization speed can make the various parts of the pipeline evenly stressed, avoid excessive local stress concentration, and thus reduce the risk of pipeline bursting; effectively reduce the water hammer effect and protect the pipeline and connecting equipment.

[0069] When the pressure is increased to 0.2 times the test pressure (7.5*0.2=1.5bar), the pressure is suspended and the pressure is maintained for 10-15 minutes; when the pressure is continued to be increased to 0.5 times the test pressure (7.5*0.5=3.75bar), the pressure is suspended and the pressure is maintained for 10-15 minutes; when the pressure is continued to be increased to 0.8 times the test pressure (7.5*0.8=6bar), the pressure is suspended and the pressure is maintained for 10-15 minutes; check whether the pipeline to be pressure tested is leaking, if there is a leak, repeat S2 after repair, if there is no leak, continue to pressurize to the test pressure; in this embodiment, the test pressure can be 1.5 times the working pressure of the pipeline to be pressure tested 100. Setting the test pressure to 1.5 times the working pressure comprehensively considers the characteristics of the GRP pipeline material itself, so that the test pressure is not too low, resulting in defects in the GRP pipeline, such as cracks, pores, etc., which cannot be tested, affecting the pressure test effect; nor is the test pressure too high, resulting in the risk of pipeline damage. 1.5 times the working pressure simulates extreme working conditions such as water hammer and temperature changes to a certain extent, and can more comprehensively evaluate the pressure resistance of the pipeline.

[0070] S3: Main water pressure test: After reaching the test pressure, maintain the pressure for 30-35 minutes. If the pressure drops during the pressure maintenance period, water will be injected to increase the pressure, but the pressure shall not be higher than the test pressure. Since the pressure may fluctuate due to the influence of temperature environment, the reliability of the pressure test can be ensured by injecting water to increase the pressure in this case, but the pressure after the pressure increase shall not be higher than the test pressure to avoid overpressure damage to the GRP pipeline caused by temperature changes.

[0071] If the pressure drop is ≤0.02MPa during the pressure maintenance period, the pressure can be reduced to the working pressure and maintained for 30-35 minutes; during the pressure maintenance period, check whether the pipe interface, pipe body and pressure gauge 4 are damaged or leaking. If there is leakage, repeat S2-S3 after repair; if there is no leakage, the main water pressure test is over. Keep records throughout the GRP pipe pressure test, record the time and pressure gauge 4 readings every 10 minutes, whether the joints are leaking, whether the limit settings such as blind plate 1 are abnormally loose, etc. If the pressure cannot be maintained in a short time, it is necessary to determine whether it is caused by temperature changes.

[0072] S4: Drain water and release pressure, and dismantle the temporary pressure test system. After the main water pressure test is completed, the water is released after the pressure is released, the drainage valve 21 is opened, and the water in the pipeline to be pressure tested 100 is pumped to a nearby water truck; the temporary pressure test system is dismantled, and the pipeline system is restored.

[0073] The GRP pipeline pressure test method provided in this embodiment first conducts a pre-hydraulic pressure test: the pressure is finally increased to the test pressure according to 0.2 times the test pressure, 0.5 times the test pressure, and 0.8 times the test pressure, and the pressure is gradually increased to avoid stress concentration caused by sudden pressure changes, thereby reducing the risk of sudden rupture of the GRP pipeline. After each level of pressurization is in place, the pressure is fully maintained, and the sealing performance of the pipeline is gradually tested. By maintaining the pressure in the low-pressure stage, slight leaks in pipeline joints, welds and other locations can be discovered in advance. These leaks may expand under high pressure and lead to serious consequences, thereby improving the reliability of the detection; after the pre-hydraulic pressure test is completed, the main water pressure test is carried out: the pressure is maintained for a long time at the two key nodes of the test pressure and the working pressure, which can fully verify the pressure bearing capacity of the pipeline and ensure its safe operation. Under the premise of ensuring safety, through the pre-hydraulic pressure test and the main water pressure test: the pressurization time is reasonably arranged to improve work efficiency.

[0074] The GRP pipe pressure testing method provided by the present invention comprehensively considers the characteristics of the GRP pipe material itself, and effectively solves the problems in the traditional pressure testing method that too fast pressure loading can easily cause damage to the GRP pipe, and too slow pressure loading can easily affect the construction period by means of segmented pressurization and multi-stage pressure maintenance.

[0075] Example 2

[0076] On the basis of Example 1, Figure 2As shown, the temporary pressure test system in S11 of this embodiment further includes a manifold 6, one end of the water inlet pipe 3 is connected to the pressure pump 7 through the manifold 6, and the other end of the water inlet pipe 3 is connected to the lower end of the pipeline 100 to be pressure tested.

[0077] The GRP pipeline pressure test method provided in this embodiment adds a manifold 6 between the pressure pump 7 and the water inlet pipe 3. In addition to being connected to the pipeline 100 to be pressure tested, the manifold 6 can also be connected to other pipelines (such as drainage pipelines) or pressure test instruments, making it convenient to perform pressure tests and making the temporary pressure test system more flexible, convenient and reliable. This not only improves the operating efficiency of the system, but also leaves room for future expansion.

[0078] Furthermore, the manifold 6 is equipped with a pressure safety valve 8, and the safety limit of the pressure safety valve 8 is 1.1 times the test pressure. When the system pressure exceeds the safety limit, the pressure safety valve 8 will automatically open to release the excess pressure, effectively preventing the system from bursting due to overpressure; setting the safety limit of the pressure safety valve 8 to 1.1 times the test pressure can avoid some unforeseen factors that may occur during the test, such as pressure increase caused by temperature. Setting a higher safety limit can provide a greater safety margin for the system.

[0079] Example 3

[0080] On the basis of Example 1 or Example 2, the GRP pipeline pressure testing method provided in this embodiment, when S2 performs a pre-hydraulic pressure test, displacement monitoring points are set at both ends of the pipeline 100 to be pressure tested to observe the displacement of the pipeline 100 to be pressure tested in real time.

[0081] Specifically, for example, a displacement monitoring point may be set at each end of the pipeline 100 to be pressure tested, and a laser rangefinder, a total station or a displacement sensor can be used to measure the displacement of the pipeline 100 to be pressure tested in real time, so as to effectively monitor the deformation of the pipeline, provide important basis for evaluating the bearing capacity of the pipeline, discovering potential defects, verifying the calculation model, etc., thereby improving the reliability of the test and ensuring the safety of the project.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A large diameter GRP pipe pressure testing method, characterized in that: The following steps are involved: S1: Carry out preparatory work before pressure test to ensure that the pipeline system is complete and the equipment required for pressure test has been brought in and can operate normally; S2: Pre-hydraulic pressure test: Pressurize the pipeline to be tested (100) in sections. When the pressure reaches 0.2 times the test pressure, stop pressurizing and keep the pressure for 10-15 minutes. Continue pressurizing to 0.5 times the test pressure and stop pressurizing and keep the pressure for 10-15 minutes. Continue pressurizing to 0.8 times the test pressure and stop pressurizing and keep the pressure for 10-15 minutes. Check whether the pipeline to be tested is leaking. If there is a leak, repair it and repeat S2. If there is no leak, continue pressurizing to the test pressure. S3: Main water pressure test: After reaching the test pressure, maintain the pressure for 30-35 minutes. If the pressure drop is ≤0.02MPa during the pressure maintenance period, reduce the pressure to the working pressure and maintain the pressure for 30-35 minutes; check whether the pipeline to be tested is leaking. If there is a leak, repeat S2-S3 after repair; if there is no leak, the main water pressure test is over; S4: Release water, release pressure and dismantle the temporary pressure test system.

2. A large diameter GRP pipe pressure testing method according to claim 1, characterized in that: S1 includes the following steps: S11: Calibrate the pressure test instrument and build a temporary pressure test system; The temporary pressure test system comprises a blind plate (1) fixedly connected to both ends of a pressure test pipeline (100); a drainage pipe (2) connected to the lower end of the pressure test pipeline (100), and a drainage valve (21) is arranged on the drainage pipe (2); a water inlet pipe (3) connected to the lower end of the pressure test pipeline (100), and a pressure gauge (4) and a water inlet valve (31) are arranged on the water inlet pipe (3); and an exhaust pipe (5) arranged at the upper end of the pressure test pipeline (100), and a pressure gauge (4) and an exhaust valve (51) are arranged on the exhaust pipe (5); S12: Close the drain valve (21), inject water into the pressure test pipeline (100) through the water inlet pipe (3), open the exhaust valve (51) before injecting water, and close the exhaust valve (51) when water flows out of the exhaust pipe (5) continuously without bubbles; S13: static soaking. Before the start of the pre-hydraulic pressure test, soak the pressure-tested pipe (100) for at least 24 hours to observe whether the liquid level drops. If leakage is found, repeat S12-S13 after inspection. If no leakage is found, proceed to the next step.

3. A large diameter GRP pipe pressure testing method according to claim 2, characterized in that: In S11, the pressure test instrument is calibrated, including the pressure gauge (4). The pressure gauge (4) has a precision of 1.5 level and a maximum range of 2 MPa.

4. A large diameter GRP pipe pressure testing method according to claim 2, characterized in that: In S12, water is injected into the pipeline (100) to be tested for pressure through the water inlet pipe (3), and the injection speed is controlled between 0.6 m / s and 1.8 m / s.

5. A large diameter GRP pipe pressure testing method according to claim 2, characterized in that: The temporary pressure test system in S11 further comprises a manifold (6), one end of the water inlet pipe (3) is connected to the pressure pump (7) via the manifold (6), and the other end of the water inlet pipe (3) is connected to the lower end of the pipeline (100) to be pressure tested.

6. A large diameter GRP pipe pressure testing method according to claim 5, characterized in that: The manifold (6) is equipped with a pressure safety valve (8), and the safety limit of the pressure safety valve (8) is 1.1 times the test pressure.

7. A large diameter GRP pipe pressure testing method according to claim 1, characterized in that: When S2 performs a pre-hydraulic pressure test, displacement monitoring points are set at both ends of the pipeline (100) to be tested, and the displacement of the pipeline (100) to be tested is observed in real time.

8. A large diameter GRP pipe pressure testing method according to claim 1, characterized in that: When S3 conducts the main water pressure test, after reaching the test pressure, the pressure is maintained for 30-35 minutes. If there is a pressure drop during the pressure maintenance period, water is injected to replenish the pressure, but the pressure shall not be higher than the test pressure.

9. A large diameter GRP pipe pressure testing method according to claim 1, characterized in that: When the pipeline to be tested (100) is pressurized in sections, the pressurization speed shall not exceed 2 bar per minute.

10. A large diameter GRP pipe pressure testing method according to claim 1, characterized in that: The test pressure is 1.5 times the working pressure of the pipeline (100) to be tested.

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