Hydraulic pressure test force transmission system and hydraulic pressure test method for mixed pipe water delivery pipe

Abstract

The invention discloses a hydraulic pressure test force transmission system and a hydraulic pressure test method for a mixed pipe water conveying pipe, and belongs to the technical field of hydraulic pressure tests. The force transmission system comprises a jack, a profile steel force transmission assembly, a back wall and a back anti-bulldozing soil body, the back anti-bulldozing soil body is arranged right opposite to the end of the water conveying pipeline, the surface of the back anti-bulldozing soil body is flat and is perpendicular to the axis of the pipeline, and the choke plug, the jack, the profile steel force transmission assembly and the back wall are sequentially arranged between the back anti-bulldozing soil body and the pipeline; the back wall is formed by stacking prefabricated reinforced concrete blocks tightly attached to a back anti-bulldozing soil body, the profile steel force transmission assembly abuts against the back wall, and the jack is arranged between the choke plug and the profile steel force transmission assembly. A force transmission system which is simple, convenient to disassemble and assemble, low in cost, capable of being recycled and free of potential safety hazards is constructed, the hydrostatic test method is easy to operate, the installation quality and the sealing performance of the mixed pipe water conveying pipe can be accurately detected, and reliable guarantee is provided for safe operation of the water conveying pipe.

Description

Technical Field

[0001] This invention relates to a force transmission system for water pressure testing and a water pressure testing method for mixed pipe water supply pipes, belonging to the field of water pressure testing technology. Background Technology

[0002] The backwall force transmission system is suitable for the hydrostatic testing phase of water transmission pipelines. Hydrostatic testing is a crucial step in water transmission pipeline construction, verifying the pipeline system's design, construction, overall stability, and the pressure-bearing capacity necessary for safe operation, ensuring long-term safe operation. Under high pressure, tests can also promptly identify and remedy defects in the pipe body itself, welds, manholes, expansion joints, and other ancillary facilities. Furthermore, it verifies the rationality, correctness, and reliability of the pipeline system's design and construction, as well as the performance of pipe materials, interface quality, weld quality, and the strength and stability of anchor blocks, thrust blocks, and supports. It also improves the stress conditions at pipe defects and reduces or eliminates existing residual stress in the pipe body.

[0003] The most crucial step in the preparatory work for hydrostatic testing is the installation of the back wall force transmission system. According to the hydrostatic testing technical specifications, the installation quality and sealing performance of the pipeline will be inspected after construction. During pressurization, an axial thrust will form inside the pipeline under high pressure. Considering the protection of the finished pipeline and the safety of the testing personnel, a back wall force transmission system needs to be installed at both ends of the pipeline to suppress the axial thrust generated inside the pipeline and prevent damage or displacement. Given the long length of the water pipeline, hydrostatic testing needs to be conducted in sections. Based on the existing back wall force transmission system scheme, technical optimization is needed to address its shortcomings. The main shortcomings of the original scheme are: 1. Traditional back walls are constructed using vertical formwork, resulting in long construction periods, high costs, and non-reusability; 2. Some force transmission systems lack pressure monitoring and buffer structures, which can cause impact damage to the force transmission system when pressure increases during pressurization, creating safety hazards. Therefore, a back wall force transmission system device that is easy to install and disassemble, low-cost, and without safety risks is needed, along with a method for conducting hydrostatic testing on mixed-material water pipelines. Summary of the Invention

[0004] (a) Technical problems to be solved The technical problem to be solved by this invention is to address the issues of long construction cycle, high cost, and inability to be reused in existing back wall force transmission systems.

[0005] (II) Technical Solution To address the aforementioned technical problems, this invention provides a hydraulic pressure testing force transmission system. This system is used for hydraulic pressure testing at the beginning and / or end of a water pipeline, and a cap is provided at the end of the pipeline. The hydraulic pressure testing force transmission system includes a jack, a steel force transmission component, a back wall, and a back thrust block. The back thrust block is positioned directly opposite the end of the water pipeline, with a flat surface and perpendicular to the pipeline axis. The cap, jack, steel force transmission component, and back wall are sequentially arranged between the back and the pipeline. The back wall is constructed by stacking precast reinforced concrete blocks tightly against the back thrust block. The steel force transmission component abuts against the back wall, and the jack is positioned between the cap and the steel force transmission component. By constructing a complete force transmission system with the jack, steel force transmission component, back wall, and back thrust block, the system can effectively transmit the enormous axial thrust generated during the hydraulic pressure test, preventing pipeline joint detachment or cap displacement, and ensuring the safety and reliability of the test.

[0006] Furthermore, the steel force transmission component includes a first steel frame, a second steel frame, and a force transmission steel plate, which are connected sequentially. The first steel frame has a larger external dimension than the second steel frame. The first steel frame abuts against the rear wall, and the second steel frame is positioned between the first steel frame and the force transmission steel plate. This design, combining steel frames from large to small, forms a gradient force transmission structure, resulting in a more uniform stress distribution and preventing structural damage caused by localized stress concentration.

[0007] Furthermore, four 100t jacks are installed between the end cap and the force transmission steel plate, and the four jacks are arranged in a circumferential array along the end cap. By arranging multiple jacks in a circumferential array, the axial thrust can be applied in a balanced manner, preventing the end cap from tilting and ensuring the stability of the test pressure.

[0008] On the other hand, the present invention provides a water pressure test method for a mixed-material water supply pipe, used for water pressure testing of a water supply pipeline, wherein the water supply pipeline is a mixed pipe of steel pipe and ductile iron pipe, and a cap is welded to the steel pipe end of the water supply pipeline, and a cap is detachably connected to the ductile iron pipe end and equipped with the water pressure test force transmission system as described in any one of claims 1-3, wherein the cap is provided with an inlet pipe, a venting pipe, and a drain pipe, each of which is provided with a gate valve, and a pressure gauge is provided on the venting pipe; the test includes the following steps: S1. Conduct the first pipeline inspection to confirm that the last welded joint of the pipeline has been completed for more than 1 hour, and that all open sections of the test pipe section are closed and there is no water leakage. S2. Water filling and soaking: Close the drain valves at both ends of the test pipe section, open the inlet pipe and the air supply valve, and then fill the pipe with water. Slowly inject water from the lowest point of the test pipe section until all air supply valves stop venting and the pipe is full of water. The soaking time after the test pipe section is filled with water shall not be less than 24 hours. During the water filling and soaking process, a second pipe inspection shall be carried out to observe whether there is any water leakage. S3. Pre-test: Close the gate valve of the air supply pipe, inject water into the test section to increase the pressure, slowly increase the water pressure in the entire line to the full static pressure, and stabilize the pressure for 30 minutes. During the pre-test, conduct a third pipeline inspection to observe whether there is any leakage, and monitor the pressure value of the water supply pipeline and the working condition of each connection part of the pipeline. S4. Main Test: Starting from static pressure, pressurize at a rate not exceeding 0.05 MPa / min with a pressure increment of 0.2 MPa, pausing for 10 minutes at each increment to reach the test pressure and stabilizing the pressure for 30 minutes. The pressure drop after stabilizing for 10 minutes should not exceed 0.03 MPa. Then, reduce the test pressure to static pressure and maintain constant pressure for 30 minutes. A fourth pipeline inspection is conducted during the main test. If there is no leakage, the water pressure test is qualified. S5. After the test is completed, drain the water and release the pressure.

[0009] The above-mentioned test method adopts a differentiated blind connection method for the characteristics of mixed pipe materials, and ensures the sealing of the connection of different types of pipe materials and the pressure bearing capacity of the overall pipeline through a multi-step, multi-checkpoint test process.

[0010] Furthermore, in step S2, the water filling flow rate is controlled at 20% of the pipeline design flow rate, and the water filling flow rate is no greater than 0.2 m³ / s, while the water filling velocity is no more than 0.3–0.5 m / s. By controlling the water filling flow rate and velocity, pressure shocks and water hammer effects caused by rapid water filling are avoided, thus protecting the safety of the pipeline structure.

[0011] Furthermore, in step S3, before the pre-test, the gas in the pipeline is purged through multiple preliminary pressure tests before the air supply and exhaust valves are closed. Then, the test section is pressurized with water using a staged loading and slow pressurization method. This pre-venting and staged loading effectively removes gas from the pipe, preventing gas compression from affecting the accuracy of pressure readings and improving the reliability of the test results.

[0012] Furthermore, during the preliminary test, the pressurization rate was no greater than 0.05 MPa / min, with a pressurization increment of 0.2 MPa. At each increment, a 10-minute pause was taken to check for leaks before continuing pressurization. Then, the water pressure throughout the entire line was gradually increased to full-pipe static pressure according to the pressure increments. This method of slow pressurization and phased pauses for inspection allows for timely detection of leaks and avoids sudden damage that might be caused by a single pressurization surge.

[0013] Furthermore, if there is a pressure drop during the pre-test pressure stabilization period, water can be injected to replenish the pressure, but the pressure must not exceed the working pressure. Appropriate pressure replenishment is permitted during the pressure stabilization period, which maintains the required test pressure value while ensuring the safety of the test process by limiting the upper limit of pressure replenishment.

[0014] Furthermore, in step S5, for test pipelines subjected to overall or segmented pressure testing, the entire pipeline is gradually depressurized simultaneously. For pipelines undergoing continuous segmented overall hydrostatic testing, the water pressure in the high-pressure section is first gradually reduced to the pressure at the junction point of the adjacent low-pressure section, until the pressure is equalized with the pressure value of the adjacent low-pressure section. After equalization, the connecting valve is opened to connect the upper and lower test pipeline sections, and then the pressure is depressurized together. Different depressurization strategies are adopted for different pressure testing methods, especially the equalization operation, which effectively avoids sudden pressure changes between different pressure sections and prevents damage to the pipeline during the depressurization process.

[0015] Furthermore, in steps S4 and S5, the pressure is gradually reduced and depressurized in stages, with a depressurization rate not exceeding 0.05 MPa / min, a pressure reduction stage difference of 0.2 MPa, and a stabilization time of 10 minutes for each stage. By controlling the depressurization rate and staged stabilization, smooth depressurization is achieved, preventing pipeline deformation or loosening of joints caused by sudden pressure drops.

[0016] (III) Beneficial Effects The above-described technical solution of the present invention has the following advantages: This invention constructs a simple, easy-to-assemble and disassemble, low-cost, recyclable, and safety-free force transmission system, fully leveraging the advantages of various materials and testing methods. This force transmission system exhibits good performance and high economic benefits. The entire system is easy to assemble and disassemble, facilitating segmented hydrostatic testing and improving testing efficiency. The hydrostatic testing method is simple to operate and can accurately detect the installation quality and sealing performance of mixed-material water pipelines, providing a reliable guarantee for the safe operation of water pipelines.

[0017] In addition to the technical problems solved by the present invention, the technical features of the technical solutions constituted by the present invention, and the advantages brought about by the technical features of these technical solutions as described above, other technical features of the present invention and the advantages brought about by these technical features will be further explained in conjunction with the accompanying drawings. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1This is a schematic diagram of the layout of the water pressure test system for the hybrid pipe material water supply system of the present invention.

[0020] Figure 2 This is a schematic diagram of the force transmission system layout for the hydrostatic test of the present invention.

[0021] Figure 3 This is a schematic diagram of the first type of steel frame of the present invention.

[0022] Figure 4 This is a schematic diagram of the second type of steel frame (including the arrangement of jacks, etc.) of the present invention.

[0023] In the diagram: 1. Water supply pipe; 2. End cap; 3. Jack; 4. Back wall; 5. Back thrust soil; 6. Type I steel frame; 7. Type II steel frame; 8. Force transmission steel plate; 9. Water inlet pipe; 10. Air supply and exhaust pipe; 11. Drainage pipe. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] Example 1 like Figure 2-4As shown, a hydraulic pressure test force transmission system is installed at the beginning and / or end of a water supply pipeline 1 for hydraulic pressure testing. A cap 2 is installed at the end of the water supply pipeline 1. The hydraulic pressure test force transmission system includes a jack 3, a steel force transmission component, a back wall 4, and a back thrust block 5. The back thrust block 5 is positioned directly opposite the end of the water supply pipeline 1. The surface of the back thrust block 5 is flat and perpendicular to the pipeline axis. The cap 2, jack 3, steel force transmission component, and back wall 4 are sequentially arranged between the two. The back wall 4 is constructed by stacking precast reinforced concrete blocks tightly against the back thrust block 5. The steel force transmission component abuts against the back wall 4, and the jack 3 is positioned between the cap 2 and the steel force transmission component. The steel force transmission assembly includes a first steel frame 6, a second steel frame 7, and a force transmission steel plate 8, which are connected sequentially (e.g., by welding or direct abutment). The first steel frame 6 is larger than the second steel frame 7. The first steel frame 6 abuts against the back wall 4, and the second steel frame 7 is positioned between the first steel frame 6 and the force transmission steel plate 8. Four 100t jacks 3 are positioned between the end cap 2 and the force transmission steel plate 8, and the four jacks 3 are arranged in a circumferential array around the end cap 2.

[0027] The back thrust soil 5 must be either undisturbed soil or artificially compacted back thrust soil. The back thrust soil 5 should be treated according to the geological conditions revealed after on-site excavation. If the geological conditions are good, vertical step excavation should be used for the back thrust soil 5. If the geological conditions are poor, replacement should be used. If the back thrust soil 5 is soft or not compacted, it should be excavated, replaced, and compacted. If there are loose or voids between the concrete back wall 4 and the original soil (backfilled and compacted soil), crushed stone should be used for artificial backfilling and compaction, with a compaction degree of not less than 95%. At the same time, the back thrust soil 5 should be increased with counterweight load by adding a 1.5m high soil layer at the existing ground elevation. The backfill soil should be compacted to reduce the soil compression ratio.

[0028] Example 2 This embodiment provides a water pressure test method for a mixed-material water supply pipe, used for water pressure testing of water supply pipeline 1, wherein the water supply pipeline 1 is a mixed pipe of steel pipe (specifically Q355C steel pipe) and ductile iron pipe, such as... Figure 1 As shown, a plug 2 is welded to the steel pipe end of the water supply pipeline 1, and a plug 2 is detachably connected to the ductile iron pipe end (e.g., using a socket and spigot conversion with a flange at the joint, and a bolt assembly circumferentially connected to the flange). The water pressure test force transmission system described in Example 1 is also installed to ensure the test pressure is evenly distributed to the back soil. It should be noted that the water pressure test force transmission system described in Example 1 is not required at the steel pipe end of the water supply pipeline 1. The plug 2 is equipped with an inlet pipe 9, a vent pipe 10, and a drain pipe 11, each with a gate valve. A pressure gauge is installed on the vent pipe 10. The plug 2 is made of steel pipe with a steel plate welded to one end.

[0029] The experiment includes the following steps: S1. Conduct the first pipeline inspection to confirm that the last welded joint of the pipeline has been completed for more than 1 hour, all open ends of the test pipe section are sealed, and there is no water leakage; specifically, it can also be to check that the pipeline auxiliary equipment is reinforced and anchored as required; the test water source, test site, and test personnel have been secured, and the test equipment and monitoring equipment have been installed and debugged. S2. Water Filling and Immersion: Close the gate valves 11 on both ends of the test pipe section, open the gate valves 9 on the inlet pipe and 10 on the air supply pipe, and then fill the pipe with water. Inject water slowly from the lowest point of the test pipe section until all air supply valves stop venting and the pipe is full of water. The immersion time after filling the test pipe section should be no less than 24 hours. During the water filling and immersion process, conduct a second pipe inspection to observe for any leaks. More specifically, the water filling flow rate should be controlled at 20% of the pipe's design flow rate, and the water filling flow rate should not exceed 0.2 m³ / min. 3 / s, the water flow rate should not exceed 0.3-0.5 m / s, and the maximum should not exceed 1 m / s (for example, 88 m on site). 3 The water pump injects water at a rate of 0.024 m³ / h. 3 / s, with a maximum planned deployment of 3 units (2 in use and 1 as a backup), less than 0.2m 3 / s. Ensure effective control of the inlet water flow by installing a gate valve at the inlet. If any abnormality is detected during the water filling process, stop filling and drain the water for inspection. When draining water for inspection due to abnormalities during filling, depressurization should be carried out in stages, and appropriate drainage measures should be taken. The discharge point should not affect the surrounding environment or cause water accumulation, and measures should be taken to ensure the safety of personnel, traffic, and auxiliary facilities. If pressure drop or leakage occurs at pipe joints or fittings during the immersion time of the test pipe section, the cause should be identified and appropriate measures taken before refilling with water. A water pressure test can only be conducted after there is no leakage or pressure drop during the immersion time.

[0030] S3. Pre-test: Close the gate valve of the air supply pipe 10, inject water to pressurize the test section, and slowly increase the water pressure throughout the entire line to the full static pressure (static pressure is the difference between the "normal water level" of the pump station outlet pool and the "center elevation of the pipe axis at the corresponding calculated point"). Stabilize the pressure for 30 minutes. During the pre-test, conduct a third pipeline inspection to observe for any leaks, and monitor the pressure value of water supply pipe 1 and the working condition of each connection point. More specifically, before the pre-test, conduct multiple preliminary pressurization tests to purge the gas in the pipeline (the following three situations indicate that the gas in the pipeline has not been completely purged, and venting should continue: 1) During pressurization, the pump continuously fills water but the pressurization is very slow. 2) During pressurization, the pressure gauge pointer swings greatly and the reading is unstable. 3) When the pressure reaches 80%, stop pressurizing, open the drain valve, and there is a "putt-putt" sound in the water column and many bubbles are ejected. Then close the gate valve 10 on the air supply and exhaust pipe, and then pressurize the test pipe section with water using a staged loading and slow pressurization method. The pressurization rate of the pre-test water injection should not exceed 0.05 MPa / min, with a pressurization increment of 0.2 MPa, and a 10-minute pause at each increment to check for leaks before continuing pressurization. Then, the water pressure throughout the entire line is slowly increased to the full static pressure according to the pressure increments. If there is a pressure drop during the pre-test pressure stabilization period, water can be injected to replenish the pressure, but it must not exceed the working pressure. S4. Main Test: Starting from static pressure, pressurize at a rate not exceeding 0.05 MPa / min with a pressure increment of 0.2 MPa, pausing for 10 minutes at each increment to reach the test pressure and stabilizing the pressure for 30 minutes. The pressure drop after stabilizing for 10 minutes should not exceed 0.03 MPa. Then, reduce the test pressure to static pressure and maintain constant pressure for 30 minutes. A fourth pipeline inspection is conducted during the main test. If there is no leakage, the water pressure test is qualified. S5. After the test, drain and depressurize. More specifically, for test pipelines subjected to overall or segmented pressure testing, depressurize the entire pipeline slowly and simultaneously; for pipelines subjected to continuous segmented overall hydrostatic testing, first slowly reduce the water pressure of the high-pressure section to the pressure at the junction point of the adjacent low-pressure section, equalizing the pressure with the adjacent low-pressure section. After equalization, open the connecting valve to connect the upper and lower test pipe sections, and then depressurize them together; after the pressure is unloaded, vent and clean the pipe. Drain the water from the beginning and end to a nearby ditch. During this process, slowly open the drain valve, ensuring the valves are not fully open, and simultaneously gradually open the air supply valves at the beginning and end or the air supply valves at both ends to ensure that gas can be replenished normally during the pipeline drainage process.

[0031] More specifically, the pressure reduction and depressurization process involves unloading in stages, slow depressurization, with a depressurization rate not exceeding 0.05 MPa / min, a pressure reduction stage difference of 0.2 MPa, and a stabilization time of 10 minutes for each stage.

[0032] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A water pressure test force transmission system, which is arranged at the head end and / or tail end of a water conveying pipeline for water pressure test, and a blind head is arranged at the end of the water conveying pipeline, characterized in that: The water pipeline is a mixed pipe of steel pipe and nodular cast iron pipe, a head is welded at the end of the steel pipe of the water pipeline, a detachable head is connected at the end of the nodular cast iron pipe, and the water pressure test transmission system of any one of claims 1-3 is arranged at the head, a water inlet pipe, a gas supplement and exhaust pipe and a drain pipe are arranged on the head, and a gate valve is arranged on each of the three pipes, and a pressure gauge is arranged on the gas supplement and exhaust pipe; the test comprises the following steps:

2. The hydrotest force transmission system of claim 1, wherein: The water pipeline is a mixed pipe of steel pipe and nodular cast iron pipe, a head is welded at the end of the steel pipe of the water pipeline, a detachable head is connected at the end of the nodular cast iron pipe, and the water pressure test transmission system of any one of claims 1-3 is arranged at the head, a water inlet pipe, a gas supplement and exhaust pipe and a drain pipe are arranged on the head, and a gate valve is arranged on each of the three pipes, and a pressure gauge is arranged on the gas supplement and exhaust pipe; the test comprises the following steps:

3. The hydrotest force transmission system of claim 2, wherein: S1, first pipeline inspection is performed, it is confirmed that the last welding interface of the pipeline is completed for more than 1 hour, all openings of the test pipe section are closed, and there is no water leakage phenomenon; 4. A method for water pressure testing of mixed-material water transmission pipes, used for water pressure testing of water transmission pipelines, characterized in that: S2, water filling and soaking: close the drain pipe gate valves at both ends of the test pipe section, open the water inlet pipe and the gas supplement and exhaust pipe gate valves, then fill water in the pipeline, slowly inject water from the low point of the test pipe section, until all the exhaust valves stop exhausting and the pipeline is full of water, the test pipe section is filled with water for not less than 24 hours; during the water filling and soaking process, the second pipeline inspection is performed to observe whether there is water leakage; S3, pre-test: close the gas supplement and exhaust pipe gate valve, pressurize the test pipe section by water injection, slowly increase the water pressure in the whole line to the full pipe static pressure, and stabilize for 30 minutes, the third pipeline inspection is performed during the pre-test to observe whether there is water leakage, and the pressure value of the water pipeline and the working condition of each connection part of the pipeline are monitored; S4, main test: increase the pressure from the static pressure at a pressure increasing speed of not greater than 0.05 MPa / min and a pressure increasing difference of 0.2 MPa, stop at each difference for 10 minutes, increase the pressure to the test pressure and stabilize for 30 minutes, the pressure decreases by not more than 0.03 MPa after stabilizing for 10 minutes, then decrease the test pressure to the static pressure and keep constant for 30 minutes, the fourth pipeline inspection is performed during the main test, if there is no water leakage, the water pressure test is qualified; S5, after the test is completed, drain and depressurize. In step S2, the water filling flow is controlled to be 20% of the design flow of the pipeline, and the water filling flow is not greater than 0.2 m³ / s, and the water filling flow speed is not greater than 0.3-0.5 m / s. In step S3, the gas in the pipeline is exhausted by preliminary pressure increasing test for multiple times before the pre-test, then the gas supplement and exhaust pipe gate valve is closed, and then the test pipe section is pressurized by water injection in a step loading and slow pressurizing mode.

5. The hydrostatic testing method of claim 4, wherein: ​ 6. The hydrostatic testing method of claim 4, wherein: ​ 7. The hydrostatic testing method of claim 6, wherein: The pressurization speed of the pre-test water injection pressurization is not greater than 0.05 MPa / min, the pressurization level difference is 0.2 MPa, and each level difference is stopped for 10 min to check whether there is leakage before continuing to pressurize, and then the water pressure in the whole line is slowly increased to the full pipe static pressure according to the pressure level difference.

8. The hydrostatic testing method of claim 7, wherein: If the pressure decreases during the pre-test pressure stabilization, water injection can be used to supplement the pressure, but it must not be higher than the working pressure.

9. The hydrostatic testing method of claim 4, wherein: In step S5, the test pipeline of the whole pressurization or segmented pressurization is slowly depressurized together; for the continuous segmented whole hydraulic test pipeline, the water pressure of the high-pressure segment is first slowly decreased to the pressure of the adjacent low-pressure segment segmentation point, which is equal to the water pressure value of the adjacent low-pressure segment, the communication valve is opened after the pressure equalization to communicate the upper and lower test pipeline segments, and then they are depressurized together.

10. The hydrostatic testing method of claim 4, wherein: In steps S4 and S5, the pressure is gradually unloaded and slowly reduced during the depressurization process, the reduction speed is not greater than 0.05 MPa / min, the depressurization level difference is 0.2 MPa, and each level has a stabilization time of 10 min.

Images