CN102854061B - Loading method for pipeline containing through cracks - Google Patents

Loading method for pipeline containing through cracks Download PDF

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Publication number
CN102854061B
CN102854061B CN201210268513.1A CN201210268513A CN102854061B CN 102854061 B CN102854061 B CN 102854061B CN 201210268513 A CN201210268513 A CN 201210268513A CN 102854061 B CN102854061 B CN 102854061B
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China
Prior art keywords
flexible container
pipeline
loading
crack
expander roll
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CN201210268513.1A
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Chinese (zh)
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CN102854061A (en
Inventor
董建令
惠虎
李笑天
雒晓卫
孔祥卫
徐宇
张启江
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清华大学
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Priority to CN201210268513.1A priority Critical patent/CN102854061B/en
Publication of CN102854061A publication Critical patent/CN102854061A/en
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Abstract

The invention belongs to the technical field of industrial pressure pipeline detecting and particularly relates to a loading method for a pipeline containing through cracks. A flexible container matched with the inner diameter size of the pipeline is selected for loading, an expansion rod is arranged in the flexible container, and a transmission medium channel is arranged on the expansion rod. The flexible channel is communicated with a loading system through the transmission medium channel on the inside expansion rod. During loading, the transmission medium enters the flexible container through the transmission medium channel on the expansion rod. When the pressure rises, the transmission medium enables the flexible container to be expanded evenly and exerts pressure on an inner wall of the pipeline to promote the cracks to expand. During the process, breaking characteristics of the cracks are measured. Due to the fact that no transmission medium leaks in the process, a loading system and a loading process are simple, safe and low in cost.

Description

A kind of loading method containing through-wall crack pipeline
Technical field
The invention belongs to industrial stresses pipeline inspection technology field, particularly a kind of loading method containing through-wall crack pipeline, especially those need the high temperature and high pressure pipeline of the special industry of the evaluation carrying out integrality, the high-temperature and pressure pipeline in such as power station.
Background technology
Pressure pipeline is at oil, and chemical industry, supplies water and heat supply and nuclear energy and space industry have a wide range of applications.But the medium carried due to these pipelines has inflammable, the character such as explosive and deep-etching, the reasons such as pipe interior is because of the reason of material itself in addition, the corrosion of mechanical damage or use procedure produce the existence of various crack defect, and pressure pipeline fracture accident happens occasionally.Failure mode containing crack defect pipeline mainly contains two kinds, i.e. brittle fracture inefficacy and leakage failure.During pipeline generation brittle fracture, the expansion rate of crackle is exceedingly fast, and consequence is catastrophic often.And when pipeline generation leakage failure, crackle had one section of stable Growth period before unstable propagation.Be controlled in the evolution of this phase accident, consequence depends on the size of leakage rate.
In order to the security these being contained to the pipeline of crack defect is evaluated, need the fracture property determining pipeline, as the tip displacement of crackle, strain field and fragmentation parameters (stress strength factor K, crack tip opening displacement COD and J integration).Current method one adopts large-sized sheet coupon to test.This method due to adopt material property and tubing have larger difference.Larger error is there is when being therefore applied to tubing.Another kind method adopts the closed at both ends of the pipeline containing crack defect to get up to form confined space, and then loading system is filled this enclosure space and pressurizeed with pressure medium.Along with the increase of this enclosure space pressure, the crack defect expansion of pipeline.Adopt optical measuring technique to measure crack tip strain field in the process, stress intensity factor and crack tip opening displacement and J integration, and determine that opening of crackle is split, expansion and unstability rule, then for the evaluation of pipeline integrity.If the pressure medium used in this process is the fluid of normal temperature, then above-mentioned measuring method can realize.Such as, but need in some cases to use high-temperature high-pressure medium, the temperature and pressure of the fluid of the pipeline that the power station in energy field uses is very high.In order to simulate the fracture characteristics of these high energy pipelines after cracking, need to use high-temperature high pressure water to carry out pipeline break simulation test as pressure medium.In such cases, above-mentioned measuring process is difficult to realize.The weak point of said method is as follows:
(1) when crack defect be extended to wear wall crackle time, the outside that high-temperature high-pressure medium can leak into pipeline produces security threat, as scalded operating personnel to the measurement of crackle.When the pressure medium that pressure process is used is high temperature and high pressure steam, the leakage of steam can make measurement carry out.Therefore, consider the factor such as material, closure, security, be difficult to carry out high temperature and pressure experiment;
(2) flowing of the fluid caused because of leakage in experimentation can produce pressure surge, brings certain error to static pressure experiment;
(3) in process fluid flow, fluid source needs constantly to supplement new fluid, and could maintain fixing pressure, device complicacy promotes greatly.
If pressure process is carried out at normal temperatures, and be use high-pressure pump direct weighting, after high-pressure liquid medium leaks, constant or make pressure continue to raise in order to maintain pressure in pipe, then the leakage rate requiring the flow of pump to be more than or equal to crackle is to make pressure continue to raise or to maintain overpressure constant.If use high pressure vessel, after high-pressure medium leaks, then need the volume of pressure vessel enough large, could when when pipe leakage, the pressure of system remains unchanged substantially.Which increase the cost of pipeline break parameter measurement.
Summary of the invention
In order to overcome above-mentioned deficiency, the invention provides a kind of loading method containing through-wall crack pipeline, adopt flexible container Bulging Technology to load the pipeline containing crackle, can stable high voltage be provided, and there will not be pressure surge, complicacy and the cost of experimental provision also reduce further.
Technical scheme of the present invention is divided into following steps:
(1) adopt size and the flexible container matched containing through-wall crack pipe interior size, and install expander roll additional at the inside axis direction of flexible container, to control the distortion of flexible container in conduit axis direction; Expander roll is provided with pressure transmitting medium passage; The flexible container installing expander roll additional is sent into containing through-wall crack pipeline;
(2) insert pressure transmitting medium by the pressure transmitting medium passage on expander roll to flexible container inside, make flexible container deformed dilation by loading system to pressure transmitting medium pressurization, flexible container surface is fitted with containing through-wall crack inner surface of pipeline;
(3) by loading system, flexible container inside pressure transmitting medium is pressurizeed further, make it load, to make Crack Extension containing through-wall crack pipeline.Observe the spread scenarios of crackle on sample pipeline and record related data.
Described flexible container is the liquid bag that fabric is made, or is the container that the deformable metal sheet material being greater than 5% by extensibility is made.The former is applicable to the situation that pressure medium is normal temperature, and the latter is applicable to the high situation of pressure medium temperature.
Described deformable metal sheet material is 304,304L, 316 or 316L corrosion resistant plate, or is 16Mn carbon steel sheet.
Combination between described flexible container and expander roll is:
The joint that expander roll is connected with loading system is outside at flexible container, and remainder is all contained by flexible container;
Or be that the two ends of expander roll, all in the outside of flexible container, are circumferential groove in the middle part of expander roll, and flexible container is arranged on the annular groove place, middle part of expander roll.
Described pressure transmitting medium is liquid or the gas of high temperature or normal temperature.
Described liquid is water or oil.
The present invention has following advantage:
(1) high pressure sealing of pressure transmitting medium is completed by flexible container, and pressure transmitting medium does not directly contact with containing through-wall crack inner-walls of duct, thus can be applicable to carry out bulging to the pipeline of various material and determines its fracture property, pressure transmitting medium also can be avoided the pollution of pipeline.Flexible container expansion uniform force, and the essentially no axial stretching of pipeline;
(2) when crack defect be extended to wear wall crackle time, high-temperature high-pressure medium can not leak into the outside of pipeline, thus can not produce security threat to the measurement of crackle.Therefore, may be used for carrying out high temperature and pressure experiment;
(3) leak without fluid in experimentation, can not pressure surge be produced;
(4) supplement without the need to new fluid, device is simple, and strong adaptability is easy to use.
Accompanying drawing explanation
Fig. 1 is the structural representation of flexible container and expander roll;
Fig. 2 is the loading system figure used containing the research of crack defect pipeline crack propagation law.
Number in the figure:
1-pipeline, 2-flexible container, 3-expander roll, 4-connector, 5-pressure transmitting medium passage, 6-oil pump, 7-retaining valve, 8-tensimeter, 9-blowdown valve, 11-pressure medium storage tank.
Embodiment
The invention provides a kind of loading method containing through-wall crack pipeline, below in conjunction with the drawings and specific embodiments, the present invention will be further described.
Adopt the flexible container shown in Fig. 1 and expander roll structure, and the loading system shown in Fig. 2.
Embodiment 1
When pressure medium is normal temperature, the present invention is adopted to load containing through-wall crack heat-transfer pipe sample steam generator.
(1) Piping specimen that first, processing dimension is suitable.For eliminating end effect, sample pipeline 1 length should be made in sample preparation to be greater than 2 times of expander roll 3 effective pressurization length.And axial crack is prepared on pipeline 1;
(2) flexible container 2 adopting size and pipeline 1 inside dimension to match, and install expander roll 3 additional at the inside axis direction of flexible container 2, to control the distortion of flexible container in conduit axis direction, the wherein liquid bag made for fabric of flexible container 2; Expander roll 3 is provided with pressure transmitting medium passage 5; The flexible container 2 having installed expander roll 3 additional is sent into pipeline 1;
(3) structure of loading system is: the inlet end of oil pump 6 stretches in pressure medium storage tank 11, after endpiece is connected with retaining valve 7, be connected with expander roll 3 by connector 4, tensimeter 8 is set between retaining valve 7 and expander roll 3, and pressure relief pipe and blowdown valve 9 are set between expander roll 3 and pressure medium storage tank 11; Inserting pressure transmitting medium by the pressure transmitting medium passage 5 on expander roll 3 to flexible container 2 inside, make flexible container 2 deformed dilation by loading system to pressure transmitting medium pressurization, fits with pipeline 1 inside surface in flexible container 2 surface;
(4) by loading system, flexible container inside pressure transmitting medium is pressurizeed further, make it load, to make Crack Extension containing through-wall crack pipeline; Observe the spread scenarios of crackle on sample pipeline, adopt optical measurement or other technologies record related data simultaneously.
Embodiment 2
When pressure medium is high temperature, adopts the present invention to carry out steam generator and load containing through-wall crack heat-transfer pipe.
(1) Piping specimen that first, processing dimension is suitable.For eliminating end effect, sample pipeline 1 length should be made in sample preparation to be greater than 2 times of expander roll 3 effective pressurization length.And axial crack is prepared on pipeline 1;
(2) flexible container 2 adopting size and pipeline 1 inside dimension to match, and install expander roll 3 additional at the inside axis direction of flexible container 2, to control the distortion of flexible container in conduit axis direction, wherein flexible container 2 is made up of deformable metal; Expander roll 3 is provided with pressure transmitting medium passage 5; The flexible container 2 having installed expander roll 3 additional is sent into pipeline 1; Loading system and expander roll 3 are by flange or be welded to connect, and pipeline 1 is placed on expander roll 3 outside surface, and lay heat-insulation layer outside pipeline 1, preliminary work completes;
(3) structure of loading system is identical with embodiment 1; Inserting pressure transmitting medium by the pressure transmitting medium passage 5 on expander roll 3 to flexible container 2 inside, make flexible container 2 deformed dilation by loading system to pressure transmitting medium pressurization, fits with pipeline 1 inside surface in flexible container 2 surface;
(4) by loading system, flexible container inside pressure transmitting medium is pressurizeed further, make it load, to make Crack Extension containing through-wall crack pipeline; Regulate different force value, observe the spread scenarios of crackle on sample pipeline, adopt optical measurement or other technologies record related data simultaneously.

Claims (4)

1., containing a loading method for through-wall crack pipeline, it is characterized in that there are following steps:
(1) adopt size and the flexible container matched containing through-wall crack pipe interior size, and install expander roll additional at the inside axis direction of flexible container, expander roll is provided with pressure transmitting medium passage; The flexible container installing expander roll additional is sent into containing through-wall crack pipeline; For eliminating end effect, be greater than 2 times of expander roll effective pressurization length containing through-wall crack duct length; Flexible container is the liquid bag that fabric is made, or is the container that the deformable metal sheet material being greater than 5% by extensibility is made;
(2) insert pressure transmitting medium by the pressure transmitting medium passage on expander roll to flexible container inside, make flexible container deformed dilation by loading system to pressure transmitting medium pressurization, flexible container surface is fitted with containing through-wall crack inner surface of pipeline; Described pressure transmitting medium is liquid or the gas of high temperature or normal temperature;
(3) by loading system, flexible container inside pressure transmitting medium is pressurizeed further, make it load, to make Crack Extension containing through-wall crack pipeline; Observe the spread scenarios of crackle on sample pipeline and record related data.
2. a kind of loading method containing through-wall crack pipeline according to claim 1, is characterized in that, described deformable metal sheet material is 304,304L, 316 or 316L corrosion resistant plate, or is 16Mn carbon steel sheet.
3. a kind of loading method containing through-wall crack pipeline according to claim 1, it is characterized in that, the combination between described flexible container and expander roll is:
The joint that expander roll is connected with loading system is outside at flexible container, and remainder is all contained by flexible container;
Or be that the two ends of expander roll, all in the outside of flexible container, are circumferential groove in the middle part of expander roll, and flexible container is arranged on the annular groove place, middle part of expander roll.
4. a kind of loading method containing through-wall crack pipeline according to claim 1, it is characterized in that, described liquid is water or oil.
CN201210268513.1A 2012-07-31 2012-07-31 Loading method for pipeline containing through cracks CN102854061B (en)

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CN105352806B (en) * 2015-11-23 2018-09-14 中国人民解放军陆军工程大学 The pressure method of pressue device
CN106018114A (en) * 2016-08-11 2016-10-12 南通永大管业股份有限公司 High pressure damage-resistant testing device of steel pipe
CN106918507B (en) * 2017-03-29 2019-08-16 中国石油大学(华东) Half Cracked pipe fracture stimulation experimental provision of unidirectional drive formula and experimental method
CN106989996B (en) * 2017-03-29 2019-10-11 中国石油大学(华东) One-way hydraulic enlarged diameter type pipeline break imitative experimental appliance and experimental method
CN106840886B (en) * 2017-03-29 2019-09-06 中国石油大学(华东) Bi-directional drive type pipeline break imitative experimental appliance and experimental method
CN107063868B (en) * 2017-03-29 2019-09-06 中国石油大学(华东) Bidirectional hydraulic enlarged diameter type pipeline break imitative experimental appliance and experimental method
CN106918510B (en) * 2017-03-29 2019-09-06 中国石油大学(华东) Pressure expansion formula pipeline break imitative experimental appliance and experimental method
CN106950114B (en) * 2017-03-29 2019-07-16 中国石油大学(华东) One-way hydraulic drive-type totally cleaves line pipeline break imitative experimental appliance and experimental method

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