Method and device for hydrostatic test of large-diameter long-distance combined pipeline

Abstract

The invention discloses a large-diameter long-distance combined pipeline water pressure test method and device, the method comprises the steps of dividing a large-diameter long-distance combined pipeline into a plurality of test sections, and sequentially carrying out water pressure test on the plurality of test sections, and the water pressure test on each test section comprises the following steps: according to the material of the pipeline in the test section, carrying out water pressure test on the pipeline in the test section; plugging blind plates matched with the pipeline are mounted at the two ends of the test section respectively; a plurality of pressurized water injection assemblies are mounted on the pipeline of the test section; constructing backrest walls for supporting the test section pipeline at the two ends of the test section respectively; and performing a hydrostatic test on the pipeline through the plurality of pressurized water injection assemblies to determine whether the pipeline leaks or not. According to the method, the pipeline test frequency is reduced, the construction period is shortened, the test cost is reduced, and the construction safety is improved.

Description

Technical Field

[0001] This invention relates to the field of combined pipeline hydrostatic testing technology, and in particular to a method and apparatus for hydrostatic testing of large-diameter, long-distance combined pipelines. Background Technology

[0002] During the construction of water pipelines, it may be necessary to cross rivers, highways, railways, etc. Sometimes the open-cut method is used for installation, and in some sections, pipe jacking is required. Water pipelines sometimes use pipes of the same or different diameters (larger diameters often exceed 2.6 km) connected in an alternating pattern, and maintenance valve wells and concrete piers are installed along the route as needed to stabilize the pipeline. After construction, the functional testing of the water pipeline is the final quality assurance procedure before the project is completed and put into operation.

[0003] Due to the long distance and large diameter of the pipeline, the existing technology requires the water supply pipeline to be tested in sections. For example, the large-diameter pipeline water pressure test device and test method disclosed in Chinese Patent No. CN114878105A is used. That is, the pipeline is divided into sections, and the two ends of each test pipeline are sealed. After the pipeline is filled with water, a pressure testing device is connected to conduct the water pressure test.

[0004] The above methods are suitable for hydrostatic testing of water pipelines formed by connecting pipes of the same material. However, for combined pipelines formed by pipes of different materials, existing technologies often conduct hydrostatic tests in sections and batches according to the different material pipes. Furthermore, when conducting segmented hydrostatic tests on combined pipelines formed by connecting pipes of different materials, existing technologies often divide the pipelines into sections of a specified 1-kilometer distance. For large-diameter, long-distance combined water pipelines, this segmentation method significantly increases the number of hydrostatic tests and the amount of water used (often measured in tens of thousands of cubic meters), increasing water costs and significantly impacting the construction period. Moreover, the structural design of blind flanges for sealing pipes of different materials varies considerably, greatly increasing testing costs and construction difficulty. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems existing in the prior art and provide a method and apparatus for hydrostatic testing of large-diameter, long-distance combined pipelines, thereby reducing the number of pipeline tests, shortening the construction cycle, reducing testing costs, and improving construction safety.

[0006] To achieve the above objectives, the present invention provides a method for hydrostatic testing of a large-diameter, long-distance combined pipeline, comprising the steps of dividing the large-diameter, long-distance combined pipeline into multiple test sections and sequentially performing hydrostatic tests on the multiple test sections, wherein performing a hydrostatic test on each test section includes:

[0007] Based on the material of the pipes in the test section, blind flanges compatible with the pipes are installed at both ends of the test section.

[0008] Multiple pressurized water injection components were installed on the pipeline in the test section;

[0009] At both ends of the test section, back walls were constructed to provide support for the pipeline in the test section.

[0010] A water pressure test is conducted on the pipeline using multiple pressurized water injection components to determine whether any leaks have occurred.

[0011] Preferably, the installation of a pressurized water injection assembly on the pipeline in the test section includes:

[0012] Weld the pressurized water injection assembly to the flange plug plate;

[0013] Install the flange plug on the vent flange of the pipeline.

[0014] Preferably, depending on the material of the pipeline within the test section, sealing blind flanges adapted to the pipeline are installed at both ends of the test section, including:

[0015] When the pipe at the end of the test section is a ductile iron pipe, an external sealing blind flange is installed on the outside of the pipe end;

[0016] When the pipeline at the end of the test section is a steel pipeline, an internal sealing blind flange is installed inside the pipeline end.

[0017] Preferably, the back walls constructed at both ends of the test section to provide support for the pipeline in the test section include:

[0018] When the end of the test section is close to the anchor block, the anchor block is used as the back wall supporting the pipeline.

[0019] When the end of the test section is close to the valve well, the valve well is used as the back wall supporting the pipeline.

[0020] When the end of the test section is neither close to the pier nor the valve well, concrete is poured on the back side of the pipe end as a back wall to support the pipe.

[0021] Preferably, a first detachable support structure is installed between the back wall and the external sealing blind plate.

[0022] Preferably, a second detachable support structure is installed between the back wall and the built-in sealing blind plate.

[0023] Preferably, when conducting a water pressure test on the pipeline using multiple pressurized water injection components, water is sequentially injected into the pipeline along the test section in ascending order using the multiple pressurized water injection components to conduct the water pressure test.

[0024] Preferably, the water pressure test is conducted by sequentially injecting water into the pipeline through multiple pressurized water injection components in an order from low to high pressure, including:

[0025] Connect multiple ordinary water pumps to multiple water injection pipes installed on the pipeline in sequence, and inject water into the pipeline from low to high until the pipeline is full of water.

[0026] After the pipeline is filled with water, a booster pump is used to replace the ordinary water pump to gradually increase the pressure of the water. During the pressurization process, the pipeline is filled with water and the working pressure is reached by simultaneously increasing the pressure, adding water, and venting air.

[0027] Preferably, after the pipeline is filled with water and reaches the working pressure, it also includes:

[0028] The pipeline is subjected to a full water immersion test. Afterward, the water pressure inside the pipeline is increased to the test pressure by staged water injection and maintained at the test pressure for a preset time.

[0029] Preferably, when dividing the large-diameter, long-distance combined pipeline into multiple test sections, the length of the test section is between 2km and 3km.

[0030] Furthermore, the present invention also provides an apparatus for a method of hydrostatic testing of a large-diameter, long-distance combined pipeline as described above, comprising: multiple pressurized water injection components installed on the pipeline of each test segment in which the combined pipeline is divided into multiple test segments; blind sealing plates adapted to the pipeline and installed at both ends of the test segment according to the material of the pipeline within the test segment; and backrest walls respectively disposed at both ends of the test segment to provide support for the pipeline of the test segment; wherein, the pipeline is subjected to a hydrostatic test by the multiple pressurized water injection components to determine whether leakage occurs in the pipeline.

[0031] Preferably, the pressurized water injection assembly includes: a flange plug for detachable connection with a pipeline; a water injection pipe fixedly installed on the flange plug; and an exhaust pipe fixedly installed on the flange plug and arranged parallel to the water injection pipe.

[0032] Compared with the prior art, the method and apparatus for hydrostatic testing of large-diameter, long-distance combined pipelines of the present invention have the following advantages:

[0033] 1. The present invention provides a method and apparatus for hydrostatic testing of large-diameter, long-distance combined pipelines, which reduces the number of pipeline tests, shortens the construction cycle, reduces testing costs, and improves construction safety.

[0034] 2. The method and apparatus for hydrostatic testing of large-diameter, long-distance combined pipelines of this invention, when dividing the test section, the length of the test section is between 2km and 3km. Compared with the existing technology where the test section length is about 1km, this invention can greatly reduce the number of hydrostatic tests, reduce the amount of water used in the test, shorten the pipeline test period, and reduce the test cost. During the hydrostatic test, appropriate sealing blind plates are set at both ends of the test section according to the different materials of the pipeline within the test section. This ensures the success rate and safety of the hydrostatic test of the pipeline in the test section even when the test section length is increased, and prevents pipe bursts. When conducting the hydrostatic test, reasonable segmentation and the use of valve wells, anchor blocks, or cast-in-place concrete as back walls provide strong support for the pipeline in the test section, reduce test costs by adapting to local conditions, and the detachable support structure and sealing blind plates can be reused repeatedly, improving the utilization rate of test materials. It has excellent prospects for promotion.

[0035] The embodiments of the present invention will now be described with reference to the accompanying drawings. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of an apparatus used in the method for hydrostatic testing of large-diameter, long-distance combined pipelines according to the present invention;

[0037] Figure 2 yes Figure 1 A schematic diagram of the flange plug and pressurized water injection assembly used in the process;

[0038] Figures 3-6 This is a partial structural diagram of the pipe end when the present invention uses an internal sealing blind flange;

[0039] Figure 7 This is a flowchart of the method for hydrostatic testing of large-diameter, long-distance combined pipelines according to the present invention. Detailed Implementation

[0040] To address the problems of numerous test cycles, long construction periods, and high testing costs associated with hydrostatic testing of large-diameter, long-distance combined pipelines in existing technologies, this invention provides a method for hydrostatic testing of large-diameter, long-distance combined pipelines. This method includes dividing the large-diameter, long-distance combined pipeline into multiple test sections and sequentially performing hydrostatic tests on each section. For example... Figure 7 As shown, the hydrostatic test for each test section includes:

[0041] Based on the material of the pipes in the test section, blind flanges compatible with the pipes are installed at both ends of the test section.

[0042] Multiple pressurized water injection components were installed on the pipeline in the test section;

[0043] At both ends of the test section, back walls were constructed to provide support for the pipeline in the test section.

[0044] A water pressure test is conducted on the pipeline using multiple pressurized water injection components to determine whether any leaks have occurred.

[0045] Specifically, when conducting hydrostatic tests on large-diameter, long-distance combined pipelines with a diameter greater than 2000 meters, this invention breaks away from the conventional method of dividing the pipeline into approximately 1km sections based on the distribution of water sources, pipeline butterfly valve wells (hereinafter referred to as valve wells), and anchor blocks during the construction of the combined pipeline. It fully utilizes the valve wells and anchor blocks, dividing the combined pipeline into multiple test sections with a distance of 2km-3km between sections. This ensures that the test sections are as close as possible to the water source, and that the ends of each test section are as close as possible to the anchor blocks and valve wells. Furthermore, the test sections are divided using the butterfly valve expansion joints of the combined pipeline as the dividing points, and these dividing points should be far away from the diameter-changing interfaces between two sections of the combined pipeline.

[0046] The test section of the combined pipeline of this invention is divided at a distance of 2km-3km, which greatly reduces the number of water pressure tests on the entire combined pipeline, significantly reduces the amount of water used for testing, and lowers the testing cost.

[0047] After dividing the large-diameter, long-distance combined pipeline into multiple test sections, hydrostatic tests are conducted on each section sequentially. The method for conducting hydrostatic tests on multiple test sections is the same. Below, we will describe the hydrostatic test process using only one test section as an example:

[0048] S01. Based on the material of the pipeline in the test section, install sealing blind flanges that are compatible with the pipeline at both ends of the test section.

[0049] A test section in a combined pipeline can be used as follows: Figure 1 The structure shown comprises one or more sections of ductile iron pipe 2, one or more sections of steel pipe 1, and connecting flanges 3 connecting adjacent ductile iron and steel pipes. The pipes at both ends of the test section are ductile iron and steel pipes, respectively. Furthermore, a sludge discharge valve 14 is installed on any section of the test section (usually a steel pipe).

[0050] When conducting a hydrostatic test on the test section of the pipeline, the blind flanges required to be installed at both ends of the test section must be determined based on the material of the pipes located at both ends of the test section. During the design phase, the dimensions of the blind flanges must be reasonably determined according to the diameter and length of the compatible pipes.

[0051] Among them, the blind flanges used for sealing at both ends of the test section to be compatible with the pipeline include:

[0052] When the pipe at the end of the test section is a ductile iron pipe, an external sealing blind flange 8 is installed on the outside of the pipe end;

[0053] When the pipe at the end of the test section is a steel pipe, an internal sealing blind flange 9 is installed inside the pipe end.

[0054] Specifically, when one end of the test section (e.g.) Figure 1 When the pipe at the left end (as shown) is made of ductile iron, a connecting flange is welded to the outside of the left end of the ductile iron pipe (the connecting flange can also be an existing flange on the pipe used to connect to another section of the pipe), and the external sealing blind flange is bolted to the connecting flange, thereby sealing the left end opening of the test section through the external sealing blind flange.

[0055] And at the other end of the test section (such as...) Figure 1 When the pipe at the right end (as shown) is made of steel, an internal sealing blind flange is welded inside the right end of the steel pipe to seal the right end opening of the test section. By installing sealing blind flanges at both ends of the test section, the openings at both ends of the pipe section are sealed, facilitating subsequent pressure testing by injecting water into the pipe.

[0056] The external blind flange is a disc with connecting holes on its edges for mating with bolt holes or through holes on the connecting flange on the left side of the ductile iron pipe. The internal blind flange 9 can be, for example... Figures 3-6 The structure shown includes a circular plate with edges for welding to the inner wall of the pipe and a frame structure welded to the outer surface of the circular plate facing outwards from the pipe. The frame structure is formed by welding crisscrossing steel plates, and after assembly, the frame structure can extend slightly beyond the steel pipe or be flush with it. The frame structure, by abutting the circular plate, increases the pressure resistance of the built-in sealing blind flange during hydrostatic testing.

[0057] After the hydrostatic test, the built-in and external sealing blind flanges can be removed from both ends of the test section for use in the next hydrostatic test. The built-in sealing blind flange used in this invention can be applied to steel pipes of the same diameter, while the external sealing blind flange can be applied to ductile iron pipes of the same diameter. Therefore, the internal and external sealing blind flanges of this invention can be reused during the hydrostatic test, thereby reducing testing costs and construction difficulty.

[0058] The above description only uses the example of ductile iron pipes and steel pipes at both ends of the test section to illustrate the installation of blind flanges. However, it should be noted that if both ends of the test section are ductile iron pipes, then the above-mentioned external blind flanges should be installed at both ends in the same manner; if both ends of the test section are steel pipes, then the above-mentioned internal blind flanges should be installed at both ends in the same manner.

[0059] In addition, a steel pipe section about 2 meters long can be pre-welded together with an internal sealing blind plate to form a steel plug with an internal sealing blind plate. Before the hydrostatic test, the steel plug is welded to the steel pipe at the end of the test section. After each hydrostatic test, the steel plug can be directly cut off from the steel pipe and welded to the steel pipe at the end of the next test section, thereby improving the efficiency of the hydrostatic test of the next test section.

[0060] S02. Install multiple pressurized water injection components on the pipeline of the test section;

[0061] After installing blind flanges at both ends of the test section pipeline, multiple pressurized water injection components need to be installed along the test section pipeline in a certain interval from low to high, with one pressurized water injection component near each end of the test section.

[0062] Installing each pressurized water injection assembly on the pipeline includes:

[0063] Weld the pressurized water injection assembly onto the flange plug 4;

[0064] Install the flange plug on the vent flange 15 of the pipeline.

[0065] In the design, the pressurized water injection component of this invention can adopt the following... Figures 1-3 The structure shown includes: a flange plug 4 detachably connected to the vent flange of the pipeline, which can be connected by bolts (the corresponding threaded holes or through holes on the vent flange and flange plug are not shown in the figure); a water injection pipe 5 fixedly installed on the flange plug; and a vent pipe 6 fixedly installed on the flange plug and arranged parallel to the water injection pipe, on which an observation window can be installed to observe the drop in water level in the test section of the pipeline. In addition, a branch pipe perpendicularly connected to the vent pipe can be installed, and a pressure gauge 7 can be installed on the branch pipe. During manufacturing, both the water injection pipe and the vent pipe can be fixed to the flange plug by welding.

[0066] The pressurized water injection assembly is installed on the vent flange of the pipeline only during the hydrostatic test of the combined pipeline. When the combined pipeline is officially put into use, a vent valve (not shown in the figure) will be installed at the vent flange. In addition, the vent flange can also serve as the inlet and outlet for welding in the warehouse.

[0067] By installing multiple pressurized water injection components on the test section of the pipeline, water can be injected, pressurized, and vented into the pipeline simultaneously through multiple pressurized water injection components, thereby greatly shortening the pipeline water pressure test time.

[0068] S03. Construct back walls at both ends of the test section to provide support for the pipeline in the test section;

[0069] After installing the blind flange and pressurized water injection assembly on the pipeline of the test section, back walls are constructed at both ends of the test section to provide support for the pipeline. When constructing the back walls, existing anchor blocks and valve wells from the combined pipeline construction can be utilized appropriately, as shown below:

[0070] When the end of the test section is close to the anchor block, the anchor block is used as the back wall supporting the pipeline.

[0071] When the end of the test section is close to the valve well, the valve well is used as the back wall supporting the pipeline.

[0072] When the end of the test section is neither close to the pier nor the valve well, concrete 12 is poured on the back side of the pipe end as a back wall to support the pipe.

[0073] Furthermore, when a pier or valve well serves as the back wall supporting the pipeline, a first detachable support structure is installed between the blind flange and the back wall. When concrete is used as the back wall supporting the pipeline, a second detachable support structure is installed between the blind flange and the back wall.

[0074] Specifically, when constructing the back walls at both ends of the test section, if... Figure 1 As shown, the left end of the test section is close to the valve well, so the well wall of the valve well serves as the back wall for the left end; the right end of the test section is neither close to the valve well nor the anchor block, so concrete is poured on the back side (also called the rear side) of the right end of the pipeline as the back wall.

[0075] When one end of the test section (such as...) Figure 1 When the valve well wall (or pier) is used as the back wall and the blind flange as the external blind flange (as shown on the left end), a first detachable support structure needs to be installed in the gap between the valve well wall (or pier) and the external blind flange. This first detachable support structure can be an H-beam support frame 11 formed by welding multiple H-beams together. One end of the first detachable support structure abuts against the well wall, and the other end abuts against the external blind flange, thereby transferring the supporting effect of the back wall to the pipeline.

[0076] When one end of the test section (such as...) Figure 1When the valve well wall (or pier) serves as the back wall for the left end (as shown), and the blind flange is an internal blind flange (or the aforementioned steel plug with an internal blind flange), a second detachable support structure needs to be installed in the gap between the valve well wall (or pier) and the internal blind flange (or steel plug). This second detachable support structure can be the first detachable support structure described above, or a solid support block 13 with an outer diameter slightly larger than the diameter of the pipe at the left end of the test section. One end of the second detachable support structure abuts against the valve well wall (or pier), and the other end abuts against the frame structure of the internal blind flange or steel plug, thereby transferring the supporting effect of the back wall to the pipeline. When an internal blind flange is used on the pipeline, the installation distance between the internal blind flange and the valve well or pier must be less than 2 meters.

[0077] When one end of the test section (such as...) Figure 1 When the right end (as shown) uses concrete as the back wall and a blind flange as the built-in blind flange (or the aforementioned steel plug with a built-in blind flange), a second detachable support structure needs to be installed between the concrete back wall and the built-in blind flange (or steel plug). This second detachable support structure can be the first detachable support structure described above, or a solid support block with an outer diameter slightly larger than the pipe diameter of the right end of the test section. One end of the second detachable support structure abuts against the concrete back wall, and the other end abuts against the frame structure of the built-in blind flange or steel plug, thereby transferring the supporting effect of the back wall to the pipeline.

[0078] When one end of the test section (such as...) Figure 1 When the right end (as shown) uses concrete as the back wall and a blind flange as the external blind flange, the aforementioned first detachable support structure needs to be installed in the gap between the concrete and the external blind flange. One end of the first detachable support structure abuts against the concrete back wall, and the other end abuts against the external blind flange, thereby transferring the supporting effect of the back wall to the pipeline.

[0079] This invention installs blind flanges at both ends of the test section of the pipeline, each adapted to the pipeline material. The blind flanges and the pipeline are supported by a backing wall and a detachable support structure designed according to local conditions, ensuring the success rate of the pipeline hydrostatic test. After the hydrostatic test of one test section is completed, the blind flanges and the aforementioned detachable support structure can be removed and put into the hydrostatic test of the next test section of the pipeline, thereby improving the utilization rate of test materials and reducing test cost. It has a good prospect for promotion.

[0080] S04. Conduct a water pressure test on the pipeline using multiple pressurized water injection components to determine whether the pipeline is leaking.

[0081] After supporting the test section pipeline, which has been blocked at both ends by blind flanges, using the back wall and detachable support structure, the pipeline is subjected to a water pressure test by multiple pressurized water injection components installed on the test section pipeline. During the water pressure test, water is injected into the pipeline sequentially through the pressurized water injection components at the corresponding positions along the test section pipeline in order from low to high.

[0082] The water pressure test involves sequentially injecting water into the pipeline through multiple pressurized water injection components in ascending order of pressure.

[0083] Connect multiple ordinary water pumps to multiple water injection pipes installed on the pipeline in sequence, and inject water into the pipeline from low to high until the pipeline is full of water.

[0084] After the pipeline is filled with water, a booster pump is used to replace the ordinary water pump to gradually pressurize and inject water. During the pressurization process, water is added while pressurizing and air is released to fill the pipeline and reach the working pressure.

[0085] After the pipeline is filled with water and reaches the working pressure, a full water immersion test is conducted on the pipeline. Then, the water pressure in the pipeline is increased to the test pressure by staged water injection and maintained at the test pressure for a preset time.

[0086] Specifically, during water injection, a regular water pump is first used to inject water into the test section of the pipeline through the water injection pipe installed at the lowest position of the pipeline until water can no longer be injected, at which point the water injection pipe is closed. Then, water is injected into the next water injection pipe on the pipeline that is higher than the first water injection pipe, until water can no longer be injected, at which point the water injection pipe is closed, and so on. This process is repeated, with water being injected into the test section of the pipeline sequentially through the water injection pipes installed from low to high until the test section of the pipeline is filled with water.

[0087] During the water filling process, all air in the test section of the pipeline must be purged. This purging can be done using an vent pipe, vent flange, or valve located at the highest point of the test section; alternatively, a temporary vent valve can be installed on the pipeline, which is then closed after the test is passed. Once the test section is full of water, it undergoes pressurized immersion. For combined pipelines made of steel and ductile iron, the immersion time should be no less than 72 hours. During immersion, the water level in the test section is monitored through the vent pipe. After immersion, air is released and water is added until the pipeline is completely filled with water.

[0088] After immersing the pipeline in full water for 72 hours, a preliminary test of graded water injection and pressurization is conducted. Water is injected into the test section of the pipeline through the injection pipe to increase the pressure, and the pressure gauge readings are observed. After the pressure reaches 0.3 MPa, it is stabilized for 15 minutes. Then, for every 0.2 MPa increase in the pressure gauge reading, it is stabilized for 15 minutes. After reaching 0.9 MPa, for every 0.1 MPa increase, it is stabilized for 10 minutes, until the pressure gauge shows that the pressure inside the pipeline reaches the preset working pressure. For each pressure increase, the back wall, blind flanges, removable support structures, pipe body, and joints are checked. If no abnormalities are found and there is no significant pressure drop in the pipeline, the inspection record is made, and the next pressure increase is proceeded. After pressurizing to the preset pipeline test pressure, it is stabilized for 30 minutes, and the pipe joints and fittings are checked for leaks or damage. If leaks or damage are found, the pressure test should be stopped immediately, the cause identified, and appropriate measures taken before re-testing. After the preliminary test is completed and the pressure is replenished to the test pressure, it is stabilized for 15 minutes. When there is no pressure drop after 15 minutes, reduce the test pressure to the working pressure and maintain it at a constant pressure for 30 minutes. If there is no leakage during the visual inspection, the water pressure test is qualified.

[0089] After the test is completed, slowly depressurize through the vent pipe or water injection pipe at a rate of less than or equal to 0.1 MPa / min. Then, open the pre-installed sludge discharge valve 14 on the pipeline to drain the test water from the pipeline. After drainage, remove the test equipment such as the pressurized water injection components, blind flanges, and detachable support structures, and clean the test section of the pipeline.

[0090] The test water is discharged slowly through a pre-determined drainage point into a designated drainage area. During the drainage process, the air vent valve on the test section of the pipeline is opened to release water and reduce pressure, preventing a vacuum from forming in the pipeline.

[0091] This invention breaks away from the conventional segmented approach to pipeline hydrostatic testing (segmented testing within a 1km range). By utilizing the distribution of pipeline butterfly valve wells and anchor blocks, it rationally divides complex spliced ​​pipelines (including ductile iron pipelines and steel pipelines) into test segments (each segment approximately 2km-3km), thereby reducing the number of tests required for the entire pipeline. Based on the different materials of the combined pipelines for the water pressure test, appropriate sealing blind flanges are selected. For example, external flange sealing blind flanges are used at the ends of ductile iron pipes, while internal welded sealing blind flanges are used at the ends of steel pipes. This eliminates the need for segmented and batch testing according to pipe materials, enabling a one-time water pressure test for multi-material combined pipelines and improving testing efficiency. During the water pressure test, the vent flange on the test section of the pipeline can also serve as the welding entrance / exit for the personnel compartment, facilitating the welding construction of the internal sealing blind flanges and enhancing the safety of blind flange construction for combined pipelines. By rationally selecting the support form of the back wall (valve well wall, anchor block, cast-in-place concrete back wall) based on the actual environment at the end of the water pressure test section, and using a detachable support structure such as a simple I-beam support structure between the back wall and the sealing blind flange, the safety and reliability of the water pressure test for large-diameter, long-distance combined pipelines are improved. Furthermore, the detachable support structure and pressurized water injection components can be reused, reducing testing costs.

[0092] Furthermore, the present invention also provides an apparatus for hydrostatic testing of large-diameter, long-distance combined pipelines, used to perform hydrostatic testing on each of the multiple test sections that divide the aforementioned combined pipeline into, such as... Figures 1-3 As shown, it includes: multiple pressurized water injection components installed on the pipeline in the test section; blind sealing plates adapted to the pipeline and installed at both ends of the test section according to the material of the pipeline in the test section; and back walls set at both ends of the test section to provide support for the pipeline in the test section; wherein, a water pressure test is conducted on the pipeline through multiple pressurized water injection components to determine whether the pipeline leaks.

[0093] Specifically, the combined pipeline of the present invention consists of multiple sections of ductile iron pipe, multiple sections of steel pipe, and multiple connecting flanges connecting adjacent ductile iron pipe and steel pipe. A test section of the combined pipeline can be constructed using, for example... Figure 1 The structure shown includes one or more sections of ductile iron pipe, one or more sections of steel pipe, and multiple connecting flanges connecting adjacent ductile iron and steel pipes. The pipes at both ends of the test section are ductile iron and steel pipes, respectively. Furthermore, a sludge discharge valve is installed on any section of the test section (usually the steel pipe).

[0094] To conduct a hydrostatic test on the test section of the pipeline, this invention arranges multiple pressurized water injection components at intervals along the pipeline from low to high. During the hydrostatic test, these components sequentially inject water, pressurize, and vent air into the pipeline. Each pressurized water injection component includes: a flange plug 4 detachably connected to the vent flange 15 of the pipeline, which can be connected via bolts (the corresponding threaded holes or through holes on the vent flange and flange plug are not shown in the figure); a water injection pipe 5 fixedly installed on the flange plug; and a vent pipe 6 fixedly installed on the flange plug and parallel to the water injection pipe, which can be equipped with an observation window to observe the drop in water level within the test section of the pipeline. Furthermore, a branch pipe perpendicularly connected to the vent pipe can be installed, and a pressure gauge 7 can be installed on the branch pipe. During manufacturing, both the water injection pipe and the vent pipe can be fixed to the flange plug by welding.

[0095] To seal both ends of the test section pipeline, this invention determines the sealing blind flanges at both ends based on the material of the pipeline at both ends of the test section. During design, the dimensions of the sealing blind flanges must be reasonably determined according to the pipe diameter and length of the compatible pipeline. Specifically, when the pipeline at the end of the test section is a ductile iron pipeline, an external sealing blind flange 8 is installed on the outside of the pipeline end; when the pipeline at the end of the test section is a steel pipeline, an internal sealing blind flange 9 is installed inside the pipeline end.

[0096] Specifically, when one end of the test section (e.g.) Figure 1 When the pipe at the left end (as shown) is made of ductile iron, a connecting flange is welded to the outside of the left end of the ductile iron pipe (the connecting flange can also be an existing flange on the pipe used to connect to another section of the pipe), and the external sealing blind flange is bolted to the connecting flange, thereby sealing the left end opening of the test section through the external sealing blind flange.

[0097] And at the other end of the test section (such as...) Figure 1 When the pipe at the right end (as shown) is made of steel, an internal sealing blind flange is welded inside the right end of the steel pipe to seal the right end opening of the test section. By installing sealing blind flanges at both ends of the test section, the openings at both ends of the pipe section are sealed, facilitating subsequent pressure testing by injecting water into the pipe.

[0098] The external sealing blind flange is a disc with connecting holes only on its edge for fitting with bolt holes or through holes on the connecting flange on the left side of the ductile iron pipe. The internal sealing blind flange can be, for example,... Figure 4 The structure shown includes a circular plate with edges for welding to the inner wall of the pipe and a frame structure welded to the outer surface of the circular plate facing outwards from the pipe. The frame structure is formed by welding crisscrossing steel plates, and after assembly, the frame structure slightly protrudes from the steel pipe. The frame structure, by abutting the circular plate, increases the pressure resistance of the built-in sealing blind flange during hydrostatic testing.

[0099] To support the pipeline after sealing, this invention provides back walls at both ends of the test section to support the pipeline. When setting up the back walls, existing anchor blocks and valve wells 10 from the combined pipeline construction can be utilized appropriately, depending on local conditions. For example, when the end of the test section is close to an anchor block, the anchor block serves as the back wall supporting the pipeline; when the end of the test section is close to a valve well, the valve well serves as the back wall supporting the pipeline; when the end of the test section is neither close to an anchor block nor a valve well, concrete 12 is poured on the back side of the pipeline end as a back wall supporting the pipeline.

[0100] When a pier or valve well is used as the back wall supporting the pipeline, a first detachable support structure is installed between the blind flange and the back wall. When concrete is used as the back wall supporting the pipeline, a second detachable support structure is installed between the blind flange and the back wall.

[0101] Specifically, when constructing the back walls at both ends of the test section, if... Figure 1 As shown, the left end of the test section is close to the valve well, so the well wall of the valve well serves as the back wall for the left end; the right end of the test section is neither close to the valve well nor the anchor block, so concrete is poured on the back side (also called the rear side) of the right end of the pipeline as the back wall.

[0102] When one end of the test section (such as...) Figure 1 When the valve well wall (or pier) is used as the back wall and the blind flange as the external blind flange (as shown on the left end), a first detachable support structure needs to be installed in the gap between the valve well wall (or pier) and the external blind flange. This first detachable support structure can be an H-beam support frame 11 formed by welding multiple H-beams together. One end of the first detachable support structure abuts against the well wall, and the other end abuts against the external blind flange, thereby transferring the supporting effect of the back wall to the pipeline.

[0103] When one end of the test section (such as...) Figure 1 When the valve well wall (or pier) serves as the back wall for the left end (as shown), and the blind flange is an internal blind flange (or the aforementioned steel plug with an internal blind flange), a second detachable support structure needs to be installed in the gap between the valve well wall (or pier) and the internal blind flange (or steel plug). This second detachable support structure can be the first detachable support structure described above, or a solid support block 13 with an outer diameter slightly larger than the diameter of the pipe at the left end of the test section. One end of the second detachable support structure abuts against the valve well wall (or pier), and the other end abuts against the frame structure of the internal blind flange or steel plug, thereby transferring the supporting effect of the back wall to the pipeline. When an internal blind flange is used on the pipeline, the installation distance between the internal blind flange and the valve well or pier must be less than 2 meters.

[0104] When one end of the test section (such as...) Figure 1When the right end (as shown) uses concrete as the back wall and a blind flange as the built-in blind flange (or the aforementioned steel plug with a built-in blind flange), a second detachable support structure needs to be installed between the concrete back wall and the built-in blind flange (or steel plug). This second detachable support structure can be the first detachable support structure described above, or a solid support block with an outer diameter slightly larger than the pipe diameter of the right end of the test section. One end of the second detachable support structure abuts against the concrete back wall, and the other end abuts against the frame structure of the built-in blind flange or steel plug, thereby transferring the supporting effect of the back wall to the pipeline.

[0105] When one end of the test section (such as...) Figure 1 When the right end (as shown) uses concrete as the back wall and a blind flange as the external blind flange, the aforementioned first detachable support structure needs to be installed in the gap between the concrete and the external blind flange. One end of the first detachable support structure abuts against the concrete back wall, and the other end abuts against the external blind flange, thereby transferring the supporting effect of the back wall to the pipeline.

[0106] This invention installs blind flanges at both ends of the test section of the pipeline, each adapted to the pipeline material. The blind flanges and pipeline are supported by a backing wall and a detachable support structure designed according to local conditions, ensuring the success rate of the pipeline hydrostatic test. After the hydrostatic test of one test section is completed, the blind flanges and the aforementioned detachable support structure can be removed and put into the hydrostatic test of the next test section of the pipeline, thereby improving the utilization rate of test materials and reducing test cost. It has a good prospect for promotion.

[0107] Although the present invention has been described in detail above, the present invention is not limited thereto. Those skilled in the art can make modifications based on the principles of the present invention. Therefore, all modifications made in accordance with the principles of the present invention should be understood as falling within the protection scope of the present invention.

Claims

1. A method for hydrostatic testing of a large-diameter, long-distance combined pipeline, comprising the steps of dividing the large-diameter, long-distance combined pipeline into multiple test sections and sequentially performing hydrostatic tests on the multiple test sections, wherein, The hydrostatic test for each test section includes: Based on the material of the pipes in the test section, blind flanges compatible with the pipes are installed at both ends of the test section. Multiple pressurized water injection components were installed on the pipeline in the test section; At both ends of the test section, back walls were constructed to provide support for the pipeline in the test section. A water pressure test is conducted on the pipeline using multiple pressurized water injection components to determine whether any leaks have occurred.

2. The method according to claim 1, wherein installing a pressurized water injection assembly on the pipeline of the test section comprises: Weld the pressurized water injection assembly to the flange plug plate; Install the flange plug on the vent flange of the pipeline.

3. The method according to claim 1, wherein, based on the material of the pipeline within the test section, sealing blind flanges adapted to the pipeline are installed at both ends of the test section, comprising: When the pipe at the end of the test section is a ductile iron pipe, an external sealing blind flange is installed on the outside of the pipe end; When the pipeline at the end of the test section is a steel pipeline, an internal sealing blind flange is installed inside the pipeline end.

4. The method according to claim 1, wherein constructing back walls at both ends of the test section to provide support for the pipeline in the test section comprises: When the end of the test section is close to the anchor block, the anchor block is used as the back wall supporting the pipeline. When the end of the test section is close to the valve well, the valve well is used as the back wall supporting the pipeline. When the end of the test section is neither close to the pier nor the valve well, concrete is poured on the back side of the pipe end as a back wall to support the pipe.

5. The method according to claim 4, wherein a first detachable support structure is installed between the back wall and the external sealing blind plate.

6. The method according to claim 4, wherein a second detachable support structure is installed between the back wall and the built-in sealing blind plate.

7. The method according to claim 1, wherein when a water pressure test is performed on the pipeline using multiple pressurized water injection components, water is sequentially injected into the pipeline along the test section of the pipeline in an order from low to high to perform the water pressure test.

8. The method according to claim 7, wherein water is sequentially injected into the pipeline through multiple pressurized water injection components in an ascending order to conduct a water pressure test, comprising: Connect multiple ordinary water pumps to multiple water injection pipes installed on the pipeline in sequence, and inject water into the pipeline from low to high until the pipeline is full of water. After the pipeline is filled with water, a booster pump is used to replace the ordinary water pump to gradually pressurize and inject water. During the pressurization process, water is added while pressurizing and air is released to fill the pipeline and reach the working pressure. After the pipeline is filled with water and reaches the working pressure, a full water immersion test is conducted on the pipeline. Then, the water pressure in the pipeline is increased to the test pressure by staged water injection and maintained at the test pressure for a preset time.

9. An apparatus for a method of hydrostatic testing of a large-diameter, long-distance combined pipeline as described in any one of claims 1-8, comprising: Multiple pressurized water injection assemblies are installed on the pipeline of each of the multiple test sections into which the combined pipeline is divided; Blind flanges, which are adapted to the pipes and installed at both ends of the test section according to the material of the pipes in the test section; Back walls are installed at both ends of the test section to provide support for the pipeline in the test section; Among these measures, a water pressure test is conducted on the pipeline using multiple pressurized water injection components to determine whether any leakage has occurred.

10. The apparatus according to claim 9, wherein the pressurized water injection assembly comprises: Flange plugs for detachable connection to pipes; A water injection pipe that is fixedly installed on a flange plug; An exhaust pipe that is fixedly installed on a flange plug and is parallel to the water injection pipe.

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