Pressure testing and purging method and system for long-distance and large-pipe-diameter steel pipe

Abstract

The invention belongs to the technical field of pipeline interior cleaning, and discloses a pressure testing and purging method for a long-distance and large-pipe-diameter steel pipe. The pressure testing and purging method comprises the steps that S1, a pipeline is divided into a plurality of pipeline sections, exhaust valves are arranged at the highest positions of all the pipeline sections, and water escape valves are arranged at the lowest positions of all the pipeline sections; s2, a pipeline valve is closed, and water is injected into the pipeline; s3, a leakproofness test of the pipeline is carried out; s4, the injected and stored water part in the injection pipeline is discharged; s5, compressed air generated by the air compressor sequentially acts on the water injected and stored in the pipe of each pipeline section at a constant pressure until the water injected and stored in all the pipeline sections is discharged; s6, the air compressor is controlled to continuously conduct purging in the pipeline, and residual accumulated water in the pipeline is completely discharged; and S7, pressure testing is carried out, and purging is completed. By applying the pressure testing and purging method for the long-distance and large-pipe-diameter steel pipe, the reliability of cleaning sundries in the pipeline can be improved, and meanwhile, the method has the good cleaning capacity for a complex bent pipeline.

Description

Technical Field

[0001] The invention belongs to the technical field of pipeline internal cleaning, and in particular relates to a long-distance, large-diameter steel pipe pressure testing and purging method and system. Background Art

[0002] During the welding and installation process of steel pipes, hammering, electric welding and other construction methods are frequently used, and iron filings, welding slag, sand and other debris will inevitably exist in the pipes. Therefore, the pipes need to be cleaned before using them for gas and liquid transportation.

[0003] Traditional pipeline cleaning methods include water flushing and air and steam purging. For long-distance (5km and above), large-diameter (1000mm and above) metal pipelines with complex conditions such as many turns and steep slopes, traditional water flushing and air purging methods cannot guarantee the cleaning quality inside the pipe; and the application of steam purging requires the coordination of auxiliary equipment such as boilers or steam accumulators, and requires advance measurement and planning to prevent thermal deformation of the pipeline from damaging the pipeline. Not only is the construction complex and the cycle long, but it also consumes a lot of steam and is costly. At the same time, steam purging is more dangerous than the above two methods and has great safety hazards.

[0004] Because, it is urgent to provide a pressure testing and purging method and system suitable for long-distance and large-diameter steel pipes to overcome the above problems.

[0005] In view of this, this application is hereby filed. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art, such as poor pipeline purging effect, long construction period, high purging cost and great purging risk, and to provide a long-distance, large-diameter steel pipe pressure testing and purging method.

[0007] Another object of the present invention is to provide a pressure testing and purging system for long-distance, large-diameter steel pipes using the above-mentioned pressure testing and purging method.

[0008] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is: a long-distance, large-diameter steel pipe pressure testing and purging method, comprising the following steps: S1. Segment the pipeline that has passed the flaw detection inspection to form a plurality of pipeline segments that can be blocked at intervals at the connection points, wherein the highest point of any of the plurality of pipeline segments is provided with an exhaust valve, and the lowest point is provided with a drain valve; S2, closing the end valve of the pipeline, and injecting water into the pipeline through the pipeline water injection port until the pipeline is full; S3. Install a pressure test pump at the end valve to conduct a tightness test on the pipeline; S4. If the pipeline passes the tightness test, the pressure test pump is removed and part of the injected water in the pipeline is discharged through the drain valve to reduce the internal pressure of the pipeline; S5, plugging the connection of each pipeline section, connecting the air compressor to the end valve, opening the drain valve of the first pipeline section, and the compressed air generated by the air compressor acts on the water in the pipe at a constant pressure until the water in the pipeline section is discharged; Then, the drain valve of the first pipe section is closed, and the drain valve of the second pipe section is opened, so that the first pipe section and the second pipe section are connected; Repeat the above operation for the subsequent pipeline sections in sequence until all the injected water in the pipeline sections is discharged; S6. Open the end valve and close the drain valves of all pipeline sections, control the air compressor to continuously purge the pipeline, and discharge all the residual water in the pipeline through the exhaust valve; S7. Dismantle the test equipment.

[0009] According to an embodiment of the present invention, in step S1, the pipeline is segmented based on the location of the pipeline joint connection to divide the pipeline into different pipeline segments.

[0010] According to one embodiment of the present invention, step S3 includes: By using the pressure test pump, under multiple preset test pressures, it is detected whether there are leakage problems at the pipeline welds and the sealing flanges, and whether there are deformation problems of the pipeline; If it is detected that there is no leakage or deformation problem in the pipeline, the controller will conduct a tightness test on the pipeline.

[0011] According to one embodiment of the present invention, the pressure regulation process of the multiple test pressures adopts a slow pressure increase transition method.

[0012] According to an embodiment of the present invention, it is characterized in that the pipeline tightness test in step S3 includes: Reduce the test pressure to the design pressure and maintain it steady for a predetermined time.

[0013] According to an embodiment of the present invention, if a pressure drop of less than 0.05 MPa is detected after a predetermined period of time, it indicates that the pipeline has passed the tightness test.

[0014] According to one embodiment of the present invention, the highest value among the multiple test pressures is 1.5 times the design pressure.

[0015] According to an embodiment of the present invention, the basis for partially discharging the injected water in the injection pipeline through the drain valve in step S4 is: Based on the size information of the pipeline section, the injection water is discharged to the remaining 60% of the full water state of the pipeline.

[0016] According to one embodiment of the present invention, the pressure of the compressed air supplied by the air compressor is 0.4-0.6 MPa.

[0017] The present invention also provides a pressure testing and purging system for long-distance and large-diameter steel pipes, which adopts the above-mentioned pressure testing and purging method for long-distance and large-diameter steel pipes; The pressure test and purge system comprises: An exhaust valve, wherein the highest point of each of the plurality of pipeline sections is provided with the exhaust valve, and the exhaust valve (1) is configured to connect the interior of the pipeline with the outside atmosphere; A drain valve, each of which is provided at the highest point of the plurality of pipe sections, and the plurality of drain valves are configured to discharge the stored liquid in the pipe; A pressure test pump, which is arranged near the end valve and configured to provide water pressure in the pipe; An air compressor is configured to provide compressed air in the pipe.

[0018] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1) By applying the long-distance, large-diameter steel pipe pressure testing and purging method provided by the present invention, the combined air-water top blowing method can improve the reliability of cleaning debris in the pipeline, and at the same time has a better cleaning ability for complex curved pipelines; 2) In the present invention, the strength test of the pipeline is carried out in advance to avoid strength problems in subsequent tests and ensure the safety of the tightness test process.

[0019] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the drawings described below are only some embodiments. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the accompanying drawings: Figure 1 This is a flow chart of the main steps of a long-distance, large-diameter steel pipe pressure testing and purging method in an embodiment of the present invention; Figure 2 The present invention is a schematic diagram of the structural connection of a pressure testing and purging system for a long-distance, large-diameter steel pipe in an embodiment of the present invention.

[0021] Description of the main components in the figure: 1. Exhaust valve; 2. Drain valve; 3. Pressure test pump; 4. Air compressor; 5. End valve; 6. Water inlet pipe; 7. Temperature detection component; 8. Pressure detection component.

[0022] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0024] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] like Figure 1 to Figure 2 As shown, a long-distance, large-diameter steel pipe pressure testing and purging method according to the present invention comprises the following steps: S1. Segment the pipeline that has passed the flaw detection inspection to form a plurality of pipeline segments that can be blocked at intervals at the connection points, wherein the highest point of any of the plurality of pipeline segments is provided with an exhaust valve, and the lowest point is provided with a drain valve; S2, closing the end valve of the pipeline, and injecting water into the pipeline through the pipeline water injection port until the pipeline is full; S3. Install a pressure test pump at the end valve to conduct a tightness test on the pipeline; S4. If the pipeline passes the tightness test, the pressure test pump is removed and part of the injected water in the pipeline is discharged through the drain valve to reduce the internal pressure of the pipeline; S5, plugging the connection of each pipeline section, connecting the air compressor to the end valve, opening the drain valve of the first pipeline section, and the compressed air generated by the air compressor acts on the water in the pipe at a constant pressure until the water in the pipeline section is discharged; Then, the drain valve of the first pipe section is closed, and the drain valve of the second pipe section is opened, so that the first pipe section and the second pipe section are connected; Repeat the above operation for the subsequent pipeline sections in sequence until all the injected water in the pipeline sections is discharged; S6. Open the end valve and close the drain valves of all pipeline sections, control the air compressor to continuously purge the pipeline, and discharge all the residual water in the pipeline through the exhaust valve; S7. After the pressure test and purging method is completed, the test equipment is removed.

[0027] By applying the long-distance, large-diameter steel pipe pressure testing and purging method provided by the present invention, a combined air-water top blowing method is adopted, which can improve the reliability of cleaning debris in the pipeline and at the same time has a better cleaning ability for complex curved pipelines.

[0028] In a specific implementation of this embodiment, the pipeline is subjected to flaw detection before segmentation, and the flaw detection method can be one or more of the following flaw detection methods: radiographic flaw detection, ultrasonic flaw detection, magnetic particle flaw detection, etc.

[0029] In a specific implementation of this embodiment, if it is detected that the pipeline flaw detection test is qualified, the pipeline is segmented to form a plurality of pipeline segments; if it is detected that the pipeline flaw detection test is unqualified, the pipeline is repaired by welding, and the repaired pipeline is subjected to pipeline flaw detection test again. If it is unqualified, it is repaired again until the pipeline passes the flaw detection test.

[0030] In a specific implementation of this embodiment, while installing the exhaust valve and the drain valve in step S1, the valves, instruments or equipment not involved in the pressure test are also controlled to be removed or isolated by installing blind plates.

[0031] Please refer to the attached Figure 2 In a specific implementation of this embodiment, in the step S1, the basis for segmenting the pipeline is to divide the pipeline into different pipeline segments according to the positions of the pipeline joints.

[0032] In a specific implementation of this embodiment, the pipeline is segmented into a plurality of pipeline segments that can be sealed at intervals from each other at the connection, which is achieved by: providing an end valve at the connection between two pipeline joints.

[0033] In a specific implementation of this embodiment, after closing the end valve of the pipeline in step S2, the step further includes: adding a blind plate on one side of the end valve to achieve strict sealing of the interior of the pipeline.

[0034] In a specific implementation of this embodiment, step S3 includes: By using the pressure test pump, under multiple preset test pressures, it is detected whether there are leakage problems at the pipeline welds and the sealing flanges, and whether there are deformation problems of the pipeline; If it is detected that there is no leakage or deformation problem in the pipeline, the controller will conduct a tightness test on the pipeline.

[0035] In the present invention, through the above steps, the strength test of the pipeline is carried out in advance to avoid strength problems in subsequent tests and ensure the safety of the tightness test process.

[0036] In a specific implementation of this embodiment, multiple preset test pressures are in multiple relationship, namely: one times the test pressure, two times the test pressure and three times the test pressure, etc. (further description of this technical feature is also included in the following text).

[0037] In a specific implementation of this embodiment, the pressure regulation process of the multiple test pressures adopts a slow pressure increase transition method.

[0038] In the present invention, the above scheme is used to stabilize the pressure change inside the pipeline, which can avoid abnormal damage to the pipeline caused by abnormal operation, and can also reduce the working intensity of the pressure test pump to ensure the service life of the components.

[0039] Specifically, the slow pressure increase means that the transition process between two adjacent test pressures is achieved by slow pressure increase. That is, the time of the pressure increase transition process is greater than the duration of a certain test pressure; for example, the transition time from double test pressure to single test pressure is greater than the test preset time of single test pressure.

[0040] In a specific implementation of this embodiment, the pipeline tightness test in step S3 includes: Reduce the test pressure to the design pressure and maintain it steady for a predetermined time.

[0041] In a specific implementation of this embodiment, the predetermined time is determined based on: determining it according to the pipe network level.

[0042] In a specific implementation of this embodiment, if the pipe network level is a first-level pipe network, the selected scheduled time is 60 minutes; if the pipe network is registered as a second-level pipe network, the selected scheduled time is 30 minutes.

[0043] In a specific implementation of this embodiment, after a predetermined period of time has passed, if a pressure drop of less than 0.05 MPa is detected, it indicates that the pipeline has passed the tightness test.

[0044] In a specific implementation of this embodiment, the highest value among the multiple test pressures is numerically equal to the design pressure.

[0045] In another specific implementation of this embodiment, the highest value of the multiple test pressures is 1.5 times the design pressure.

[0046] In a specific implementation of this embodiment, a strength test is performed on a pipeline by a pressure test pump to detect whether there is leakage at the pipeline weld and the sealing flange and whether there is deformation of the pipeline, including five test pressures, namely, a first test pressure, a second test pressure, a third test pressure, a fourth test pressure and a fifth test pressure.

[0047] The first test pressure is 0.3 times the design pressure, the second test pressure is 0.6 times the design pressure, the third test pressure is 0.9 times the design pressure, the fourth test pressure is 1.2 times the design pressure, and the fifth test pressure is the highest test pressure, which is 1.5 times the design pressure.

[0048] In a specific implementation of this embodiment, the basis for partially discharging the injected water in the injection pipeline through the drain valve in step S4 is: According to the size information of the pipeline section, part of the injection water is discharged, and the injection water is controlled to be discharged to the remaining 60% when the pipeline is full of water.

[0049] In the present invention, through the above steps, it is ensured that the debris can be completely flushed out of the pipeline in the future, thereby improving the reliability of the air-water combined top-blowing cleaning.

[0050] In a specific implementation of this embodiment, according to the length of the test pipe section and the pressure in the pipe, the injected water is discharged to 60% of the remaining whole pipe. For ease of understanding, the calculation is based on a DN1600 pipe as an example: Pipeline volume V = πR 2 L=3.14x0.8x0.8x5500=11052.8m 3 , the flushing flow rate is not less than 1.5m / s, the flushing is 60% of the full pipe water volume, flushing 3 times, 11052.8x0.6x3=19895.04m³. That is: discharge the injection water in the pipe to the remaining 19895.04m 3 .

[0051] In a specific implementation of this embodiment, the pipeline is provided with a pressure detection component for detecting pipeline pressure and a detection component for detecting the amount of water in the pipe. The specific type and model of the component are not limited here, as long as the function of detecting pipeline pressure / detecting the amount of water in the pipe can be applied to the design of this application.

[0052] In a specific implementation of this embodiment, the pressure of the compressed air supplied by the air compressor is 0.4-0.6 MPa. The pressure required for a large pipe diameter (for example, 0.6 MPa) is greater than the pressure required for a small pipe diameter (for example, 0.4 MPa).

[0053] In a specific implementation of this embodiment, the step S7, the pressure test and purging method is completed, and the test device is removed, which also includes: removing the blind plate installed for pipeline pressure testing and purging, and restoring the instruments, valves and other components removed in the previous steps on the pipeline.

[0054] In a specific implementation of this embodiment, a temperature detection component is also installed on the pipeline. The temperature detection component is started before step S2 and is used to detect the ambient temperature. If the ambient temperature is detected to be lower than -5°C, antifreeze measures are taken. The antifreeze measures may be to inject water with a higher temperature, to install insulation cotton on the periphery of the pipeline, or other insulation means.

[0055] In a specific implementation of this embodiment, the temperature detection component is a thermometer.

[0056] Please refer to the attached Figure 2 The present invention also provides a pressure testing and purging system for long-distance and large-diameter steel pipes, which adopts the above-mentioned pressure testing and purging method for long-distance and large-diameter steel pipes; The pressure test and purge system comprises: An exhaust valve 1 is provided at the highest point of each of the plurality of pipeline sections, and the exhaust valve 1 is configured to connect the interior of the pipeline with the outside atmosphere; Drain valves 2, each of which is provided at the highest point of the plurality of pipe sections, and the plurality of drain valves 2 are configured to discharge the stored liquid in the pipe; A pressure test pump 3, which is arranged near the end valve 5 and configured to provide water pressure in the pipe; The air compressor 4 is configured to provide compressed air in the pipe.

[0057] In the present invention, by applying the pressure test and purging system, the cleaning of the inside of long-distance, large-diameter complex curved pipelines is achieved. Compared with existing designs, the construction period and construction cost are reduced, and the construction efficiency is improved.

[0058] In a specific implementation of this embodiment, the pressure test and purge system further includes: A water inlet pipe 6, which is arranged at the water injection port, and water is injected into the pipeline through the water inlet pipe 6; A temperature detection component 7, wherein the temperature detection component 7 is used to detect the ambient temperature; The pressure detection component 8 is used to detect the pressure in the pipeline.

[0059] The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content suggested above without departing from the scope of the technical solution of the present invention. The implementation scheme in the above embodiment can also be further combined or replaced. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the solution of the present invention.

Claims

1. A long-distance, large-diameter steel pipe pressure testing and purging method, characterized in that: The following steps are involved: S1. Segment the pipeline that has passed the flaw detection inspection to form a plurality of pipeline segments that can be blocked at intervals at the connection points, wherein the highest point of any of the plurality of pipeline segments is provided with an exhaust valve, and the lowest point is provided with a drain valve; S2, closing the end valve of the pipeline, and injecting water into the pipeline through the pipeline water injection port until the pipeline is full; S3. Install a pressure test pump at the end valve to conduct a tightness test on the pipeline; S4. If the pipeline passes the tightness test, the pressure test pump is removed and part of the injected water in the pipeline is discharged through the drain valve to reduce the internal pressure of the pipeline; S5, plugging the connection of each pipeline section, connecting the air compressor to the end valve, opening the drain valve of the first pipeline section, and the compressed air generated by the air compressor acts on the water in the pipe at a constant pressure until the water in the pipeline section is discharged; Then, the drain valve of the first pipe section is closed, and the drain valve of the second pipe section is opened, so that the first pipe section and the second pipe section are connected; Repeat the above operation for the subsequent pipeline sections in sequence until all the injected water in the pipeline sections is discharged; S6. Open the end valve and close the drain valves of all pipeline sections, control the air compressor to continuously purge the pipeline, and discharge all the residual water in the pipeline through the exhaust valve; S7. Dismantle the test equipment.

2. A long-distance, large-diameter steel pipe pressure testing and purging method according to claim 1, characterized in that: In the step S1, the pipeline is segmented based on the location of the pipeline joint connection to divide the pipeline into different pipeline segments.

3. A long-distance, large-diameter steel pipe pressure testing and purging method according to claim 1, characterized in that: The step S3 comprises: By using the pressure test pump, under multiple preset test pressures, it is detected whether there are leakage problems at the pipeline welds and the sealing flanges, and whether there are deformation problems of the pipeline; If it is detected that there is no leakage or deformation problem in the pipeline, the controller will conduct a tightness test on the pipeline.

4. A long-distance, large-diameter steel pipe pressure testing and purging method according to claim 3, characterized in that: The pressure regulation process of the multiple test pressures adopts a slow pressure increase transition method.

5. A long-distance, large-diameter steel pipe pressure testing and purging method according to claim 3, characterized in that: The pipeline tightness test described in step S3 includes: Reduce the test pressure to the design pressure and maintain it steady for a predetermined time.

6. A long-distance, large-diameter steel pipe pressure testing and purging method according to claim 5, characterized in that: After a predetermined period of time, if a pressure drop of less than 0.05 MPa is detected, it means that the pipeline has passed the tightness test.

7. A long-distance, large-diameter steel pipe pressure testing and purging method according to claim 5, characterized in that: The highest value among the multiple test pressures is 1.5 times the design pressure.

8. A long-distance, large-diameter steel pipe pressure testing and purging method according to claim 1, characterized in that: The basis for partially discharging the injected water in the injection pipeline through the drain valve in step S4 is: Based on the size information of the pipeline section, the injection water is discharged to the remaining 60% of the full water state of the pipeline.

9. A long-distance, large-diameter steel pipe pressure testing and purging method according to any one of claims 1 to 8, characterized in that: The pressure of the compressed air supplied by the air compressor is 0.4-0.6MPa.

10. A pressure testing and purging system for long-distance, large-diameter steel pipes, characterized in that: A pressure testing and purging method for long-distance, large-diameter steel pipes according to any one of claims 1 to 9; The pressure test and purge system comprises: An exhaust valve (1), wherein the exhaust valve (1) is disposed at the highest point of each of the plurality of pipeline sections, and the exhaust valve (1) is configured to connect the interior of the pipeline with the outside atmosphere; A drain valve (2), wherein the drain valve (2) is disposed at the highest point of each of the plurality of pipeline sections, and the plurality of drain valves (2) are configured to discharge the stored liquid in the pipe; A pressure test pump (3), the pressure test pump (3) being arranged at a position close to the end valve, and the pressure test pump (3) being configured to provide water pressure in the pipe; An air compressor (4), wherein the air compressor (4) is configured to provide compressed air in the pipe.

Images