Pressure testing device for large pipeline and use method of pressure testing device

Abstract

The invention discloses a pressure testing device for a large pipeline and a using method thereof, and belongs to the technical field of pipeline pressure testing equipment, the pressure testing device comprises a pressure testing pipeline, and is characterized in that the pressure testing device comprises a centrifugal pump and a water filling bin, the upper part of the water filling bin is connected with a valve a through a pipeline a, the lower part of the water filling bin is communicated with a valve d through a pipeline b, and the pipeline b is provided with a pipeline c and a pipeline d; the pipeline c is located above the pipeline d, a valve b, a valve e and a centrifugal pump are arranged on the pipeline c, and a valve c and a pressure test bag are arranged on the pipeline d; a rubber piston is further included, and a signal emitter is arranged in the rubber piston. The tail end of the pressure testing pipeline is provided with a valve f and a valve g, and the pressure testing device is mainly applied to the aspect of pressure testing of large-scale long-distance pipelines.

Description

Technical Field

[0001] The invention belongs to the technical field of pipeline pressure testing equipment, and in particular relates to a pressure testing device for a large pipeline and a use method thereof. Background Art

[0002] A pipeline refers to a conveying device connected by pipes, pipe connectors and valves for conveying gas, liquid or fluid with solid particles.

[0003] Pipes are widely used, mainly in water supply, drainage, heating, gas supply, long-distance transportation of oil and natural gas, agricultural irrigation, water conservancy projects and various industrial devices. Any pressure pipeline of a newly built device must undergo a pressure test after construction is completed.

[0004] According to the different test media, it is divided into air pressure test and hydraulic test. Air pressure test generally uses compressed air, and hydraulic test generally uses water. One reason is that the safety of the two is very different. Because of the compressibility of gas, the energy stored in the air pressure test is more than 2,500 times that of the hydraulic test. (See GB / T 20801.5-2020, Pressure Pipeline Specification Industrial Pipeline Part 5: Inspection and Testing). Once an accident occurs during the air pressure test, not only the accumulated energy must be released, but also the volume compressed during the pressurization process must be restored at the fastest speed. Its destructive power is extremely large, equivalent to the shock wave during the explosion. Therefore, air pressure is generally not used. The second reason is: the convenience of finding leaks. If an air pressure test is used, it is difficult to find when checking the leak. If a water pressure test is used, even if a very small leak occurs, it can be easily found through the wetting of the pipeline surface. Therefore, in chemical projects, before the new pipeline is put into use for the first time, the pressure test plan is preferably carried out in the form of a water pressure test.

[0005] At present, many chemical enterprises have many expansion bends in order to eliminate stress. In order to reduce the occupation of the pipe gallery, horizontal expansion bends are generally not set, but vertical expansion bends are set, so there are more high points and low points in the pipeline. Before conducting a hydraulic pressure test, it must be ensured that the pipeline is full of water and free of air. This requirement is difficult to achieve for pipelines with "n" type high points. The only solution is to increase the high-point venting and draining. However, compared with long-distance pipelines, such as our company's low-temperature ethane pipeline, the pipeline length from the wharf to the factory area is 15 kilometers, the pipe diameter is DN900, and 69 "n" type bends need to be set. Through the public pipe gallery in the park, across the construction area of ​​the neighboring unit, the living camp of the construction team and other areas, if all venting and draining are installed, it will undoubtedly increase the potential leakage points and affect the long-term stable operation of the equipment. These drains will never be used again after the device is put into production. In principle, drains are not allowed to be set for long-distance hazardous material transportation pipelines across the factory area.

[0006] When the pipeline transports low-temperature materials, the requirements for water removal are more stringent and must be dried to a dew point below -40°C before being put into use for the first time. In this case, a shower drain must also be set at the low point of the "n" type pipeline. This is also not allowed.

[0007] Therefore, for some long-distance, dangerous medium transport, and "N"-shaped pipes, the exhaust of air during the water pressure test and the drainage after the pressure test are substantial problems that bother production personnel. In order to solve the above technical problems, the applicant has established a professional team and after a long period of research and development practice, finally developed a large-scale pipeline water filling test device and its use method, which can completely solve the above technical problems, and is easy to operate, with low investment cost, and meets the requirements of production and operation. Summary of the invention

[0008] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and the technical solution adopted is as follows: a large-scale pipeline pressure test device, including a pressure test pipeline, characterized in that it includes a centrifugal pump and a water filling tank, one end of the water filling tank is provided with a blind cover, and the other end is provided with a flange, the upper part of the water filling tank is connected to a valve a through a pipeline a, and the valve a is used for exhaust, and the lower part of the water filling tank is connected to a valve d through a pipeline b, and the valve d is used for drainage,

[0009] Pipeline b is provided with pipeline c and pipeline d respectively, and pipeline c is located above pipeline d.

[0010] Pipeline c is provided with valve b, valve e and a centrifugal pump;

[0011] The pipeline d is provided with a valve c and a pressure test bag, which is a prior art and will not be described in detail by the applicant;

[0012] It also includes a rubber piston, the interior of which is provided with a signal transmitter, and the signal transmitter is used to locate the position of the rubber piston in real time.

[0013] The rubber piston is elastic and has a diameter larger than the diameter of the pressure test pipe. The diameter of the rubber piston is d, and the diameter of the pressure test pipe is D, 1.01D≤d≤1.05D. The purpose is to obtain friction and a certain sealing effect after being inserted into the pipe. The rubber piston contains a positioning transmitter to ensure that the real-time position can be tracked when walking in a long-distance pipe.

[0014] The structure of the water filling tank is a straight-through pipe with the same diameter as the pressure test pipe;

[0015] The blind cover is connected by hinges and can be opened and closed freely;

[0016] Valve f and valve g are respectively provided at the ends of the pressure test pipeline.

[0017] In order to ensure that the rubber piston does not fall when the U-shaped tube goes down, the friction between the piston and the tube wall must satisfy the following formula: f = π·(D / 2) 2 ·h·ρ·g+M·g.

[0018] π: Pi.

[0019] D: The diameter of the pipe under test pressure.

[0020] h: The height of the “n” type bend.

[0021] ρ: Density of the test pressure medium, that is, the density of water.

[0022] g: acceleration due to gravity.

[0023] M: The mass of the rubber piston.

[0024] The pump outlet pressure (F) must satisfy the following formula: F-ΔP>f / ( π (D / 2) 2 )

[0025] f: Friction between rubber piston and tube wall

[0026] ΔP: Design pressure drop when the pipeline is operating normally. This is a commonly used formula in chemical engineering design. It is not explained in detail in this patent and is not within the scope of protection of this patent.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. Solved the problem that some long-distance pipelines that transport dangerous media and have "n"-shaped bends cannot be fully filled with water and cannot complete water pressure tests.

[0029] 2. At the same time, it solves the problem of water removal in low-temperature material conveying pipelines, which have extremely strict requirements on the dryness of the pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention is further described below in conjunction with the accompanying drawings and embodiments;

[0031] Figure 1 The working principle of the present invention Figure 1 ;

[0032] Figure 2 The working principle of the present invention Figure 2 ;

[0033] Figure 3 This is a working principle diagram of the rubber piston of the present invention;

[0034] Figure 4 This is a diagram showing the internal structure of the rubber piston of the present invention. DETAILED DESCRIPTION

[0035] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0036] Example 1

[0037] like Figure 1-Figure 4 Shown:

[0038] A pressure test device for a large pipeline, comprising a pressure test pipeline 12, characterized in that it comprises a centrifugal pump 10, a water filling tank 8, one end of the water filling tank 8 is provided with a blind cover 8-1, and the other end is provided with a flange 8-2, the upper part of the water filling tank 8 is connected to a valve a1 through a pipeline a, and the valve a1 is used for exhaust, the lower part of the water filling tank 8 is connected to a valve d4 through a pipeline b, and the valve d4 is used for drainage, pipeline b is respectively provided with a pipeline c and a pipeline d, pipeline c is located above pipeline d, and pipeline c is provided with a valve b2, a valve e5 and a centrifugal pump 10;

[0039] Pipeline d is provided with valve c3 and pressure test bag 9;

[0040] It also includes a rubber piston 11, and a signal transmitter 11-1 is arranged inside the rubber piston 11;

[0041] The rubber piston 11 is elastic and has a diameter larger than the diameter of the pressure test pipe. The diameter of the rubber piston 11 is d, and the diameter of the pressure test pipe is D, where 1.01D≤d≤1.05D;

[0042] The structure of the water filling tank 8 is a straight-through pipe and its diameter is the same as that of the pressure test pipe;

[0043] The blind cover 8-1 is connected by a hinge and can be opened and closed freely;

[0044] The ends of the pressure test pipe 12 are provided with valves f6 and g7. 。

[0045] The working principle of the present invention is as follows:

[0046] Step a: Connect the flange 8-2 of the water filling tank 8 to the pressure tested pipe 12, open the blind cover 8-1 of the water filling tank 8, and insert the rubber piston 11 into the water filling tank 8 to the water filling port and the air discharge port;

[0047] Step b: close the blind cover 8-1, open valve a1, close valve b2, close valve c3, close valve d4, slightly open valve e5, fully open valve f66 and valve g7 at the end of the pressure test pipe 12 to ensure that the back road is unobstructed, and after starting the centrifugal pump 10, immediately fully open valve e5 for reflux, and after the centrifugal pump 10 runs stably, slowly open valve b2, and at the same time close the reflux valve e5, slowly drain to the water filling tank 8, and at the same time observe whether the exhaust of valve a1 is smooth. When water starts to spray out of valve a1, it proves that the air in the water filling tank 8 has been exhausted at this time, and slowly close valve a1. At this time, as water is continuously injected, relying on the incompressibility of water, the rubber piston 11 begins to be pushed forward. The rubber piston 11 is passively advanced. The volume of the pipe through which the rubber piston 11 moves is the same as the volume of the injected water. During this water injection process, there will be no gas space in the pipe, thereby meeting the requirement that no air is allowed in the liquid pressure test;

[0048] Step c: according to the signal transmitter 11-1 in the rubber piston 11, timely track the position of the rubber piston 11, monitor that the rubber piston 11 passes the last "n" type bend, slowly close the valve f6 at the end of the pressure test pipeline, and only keep the valve f7 in the open state, and at the same time slightly open the valve e5 to slow down the speed of water injection. When water sprays out from the valve f7, it is considered that the water injection of the entire pipeline is completed, close the valve f7, close the valve b2, close the valve e(5), stop the pump, and the water injection is completed. At this time, the entire pipeline is full of water, and there is no air in any dead point.

[0049] Step d: Open the pressure test bag 9 and valve c3 to perform a pressure test on the pipeline. After the pressure test is completed, close valve c3, open valve d4, start draining, then open the blind cover 8-1, insert a rubber piston 11, fully open the valve f6 at the end of the test pipeline, connect the factory air from valve a (1) or valve d (4), use compressed air as the medium, push the rubber piston forward, and then use the rubber piston 11 to drive out the water in the "N" type bend.

[0050] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A pressure test device for a large pipeline, comprising a pressure test pipeline (12), characterized in that: The invention comprises a centrifugal pump (10) and a water filling tank (8). One end of the water filling tank (8) is provided with a blind cover (8-1) and the other end is provided with a flange (8-2). The upper part of the water filling tank (8) is connected to a valve a (1) through a pipeline a. The valve a (1) is used for exhausting air. The lower part of the water filling tank (8) is connected to a valve d (4) through a pipeline b. The valve d (4) is used for draining water. Pipeline b is provided with pipeline c and pipeline d respectively, pipeline c is located above pipeline d, and pipeline c is provided with valve b (2), valve e (5) and centrifugal pump (10); A valve c (3) and a pressure test bag (9) are provided on the pipeline d; It also includes a rubber piston (11), wherein a signal transmitter (11-1) is arranged inside the rubber piston (11); The rubber piston (11) is elastic and has a diameter greater than the diameter of the pressure test pipe. The diameter of the rubber piston (11) is d, and the diameter of the pressure test pipe is D, where 1.01D≤d≤1.05D. The structure of the water filling tank (8) is a straight-through pipe and has the same diameter as the pressure test pipe; The blind cover (8-1) is connected by a hinge and can be opened and closed freely; A valve f (6) and a valve g (7) are respectively provided at the ends of the pressure test pipeline (12).

2. The method for using a large-scale pipeline pressure testing device according to claim 1, characterized in that: The following steps are involved: Step a: Connect the flange (8-2) of the water filling tank (8) to the pressure tested pipe (12), open the blind cover (8-1) of the water filling tank (8), and insert the rubber piston (11) into the water filling tank (8) to the water filling port and the air discharge port; Step b: Close the blind cover (8-1), open valve a (1), close valve b (2), close valve c (3), close valve d (4), slightly open valve e (5), fully open valve f (6)6 and valve g (7) at the end of the pressure test pipe (12) to ensure that the back passage is unobstructed, and after starting the centrifugal pump (10), immediately fully open valve e (5) for reflux. After the centrifugal pump (10) runs stably, slowly open valve b (2), and at the same time, close the reflux valve e (5) to slowly drain the water into the water filling tank (8), and observe the valve Check whether the exhaust of valve a (1) is smooth. When water starts to spray out of valve a (1), it means that the air in the water filling chamber (8) has been exhausted. Slowly close valve a (1). At this time, as water is continuously injected, the rubber piston (11) starts to be pushed forward due to the incompressibility of water. The rubber piston (11) moves forward passively. The volume of the pipe through which the rubber piston (11) moves is the same as the volume of the injected water. During the water injection process, there will be no gas space in the pipe, thereby meeting the requirement that no air is allowed in the liquid pressure test. Step c: according to the signal transmitter (11-1) in the rubber piston (11), the position of the rubber piston (11) is timely tracked. After the rubber piston (11) passes the last "n"-shaped bend, the valve f (6) at the end of the pressure test pipeline is slowly closed, and only the valve f (7) is kept open. At the same time, the valve e (5) is slightly opened to slow down the speed of water injection. When water is sprayed out from the valve f (7), it is considered that the water injection of the entire pipeline is completed. Then the valve f (7), the valve b (2), and the valve e (5) are closed, and the pump is stopped. The water injection is completed. At this time, the entire pipeline is full of water, and there is no air in any dead point. Step d: Open the pressure test bag (9) and valve c (3) to test the pipeline. After the pressure test is completed, close valve c (3), open valve d (4), start draining, open the blind cover (8-1), insert a rubber piston (11), fully open valve f (6) at the end of the test pipeline, connect the factory air from valve a (1) or valve d (4), use compressed air as the medium, push the rubber piston forward, and use the rubber piston (11) to drive out the water in the "n" type bend.

Images