Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
  • F16L55/16—Devices for covering leaks in pipes or hoses, e.g. hose-menders
  • F16L55/168—Devices for covering leaks in pipes or hoses, e.g. hose-menders from outside the pipe
  • F16L55/1686—Devices for covering leaks in pipes or hoses, e.g. hose-menders from outside the pipe by winding a tape

Definitions

• the invention relates to a method for repairing a defect of a conduit, in particular pipeline, for the Trans ⁇ port of a liquid or gaseous medium, wherein the pipe is wrapped in the region of the defect with a bandage comprising a plurality each composed of a fiber composite material ge ⁇ formed winding layers ,
• the invention relates to a device for repairing a defect in a pipeline, in particular pipeline, for the transport of a liquid or gaseous medium with a bandage for wrapping the pipeline in the region of the defect, wherein the bandage has several each formed of a fiber composite fabric ⁇ winding layers.
• a technique for repairing pipelines is known, for example, from US 2008/0216938 AI.
• a defect of the pipeline is first identified, which is provided after any pretreatment with a dry fiber structure, which is wound around the pipe;
• the fiber structure can also be applied in the manner of a patch only in the area of the defect.
• the dry fiber structure can be present here as a sliver or as a mat, which is impregnated with a resin.
• the resin can be fed through filling openings of a pressure shell.
• From RU 2194911 C2 discloses a further process for the repair of pipelines is known, wherein voids first cleaned, see with a filling material in a deformable state to ver ⁇ ⁇ closing and are then wrapped with high strength bands.
• a pipeline for repairing defects is sheathed with appropriate sleeves.
• the size of the sleeve is selected here only as a function of the length of the respective defect.
• the object of the present invention is to provide a method and a device, as defined above, with which or with which defects of pipelines can be repaired reliably, with the lowest possible cost of materials, the desired support effect is to be achieved.
• This object is achieved in a method of the type mentioned in that in the area of the defect of the Rohrlei ⁇ tion a pressure reduction of the medium is made from an operating pressure to a lowered pressure before the bandage is placed at the defect, with an even greater number is provided by winding layers of the bandage, the lower the pressure drop in the pipeline.
• the pressure of the medium flowing in the pipeline is lowered from the operating pressure to a lower pressure before the bandage in the region of the defect around the pipeline.
• the repair of the pipeline can thus be carried out without interrupting the operation.
• the pressure reduction can be different levels.
• the pressure of the flowing medium causes a radial expansion of the pipe, which depends on the inherent elasticity of the Ma terials the pipe.
• the radial expansion of the pipeline must not exceed a specified maximum value.
• the pipe thus has a bias or strain depending on the medium pressure after the pressure reduction when the bandage is attached to the defect.
• the number of winding layers of the bandage is determined as a function of the pressure reduction in the pipeline.
• the error size and the pipe diameter are taken into account.
• only a relatively small elongation of the pipe ⁇ line is allowed until the maximum value of the elongation is reached at which the bandage should reach the full support effect.
• the extent of the pressure reduction is now taken into account that a larger number of winding layers of the bandage is seen easily, the lower the pressure drop in the pipeline.
• the tensile rigidity of the bandage which depends on the number of layers, can be adjusted specifically to the respective pressure level in the repair of the defect. If only a slight reduction in pressure, in particular between 20% and 50% based on the maximum pressure, ie the maximum allowable operating pressure at the fault, can be taken pre for a repair process, a bandage is chosen with a correspondingly hö heren tensile strength. This can ensure ⁇ the that the bandage at the maximum value of the elongation of the Rohrlei ⁇ tion has a state of tension, which guarantees a full support ⁇ effect in the area of the defect. Due to the ge ⁇ targeted consideration of the pressure drop when attaching the bandage can also be advantageously kept the cost of materials clotting, as an oversizing of the bandage can be avoided the.
• the number of winding layers is selected such that a voltage of the bandage in the mounted state at a maximum pressure of the medium at least a fixed ⁇ set safety upper limit of a voltage of the pipeline in the region of the defect corresponds.
• the bandage can absorb at least a voltage which is built up in the area of the defect of the pipeline when the medium pressure in the pipeline increases to the maximum pressure. This ensures that the bandage unfolds a sufficient supporting effect in the area of the defect in order to reliably prevent overstretching of the defect even with a pressure increase to the maximum pressure.
• the maximum pressure corresponds to the highest permissible pressure level for which the pipeline is designed.
• the maximum pressure of the medium in this case brings into ⁇ special enes maximum value of the elongation of the pipe, which marks the end of the elastic region for the elongation of the Rohrlei ⁇ tung; a further increase in pressure would therefore lead to a plastic deformation of the pipeline.
• the layer number of the bandage is dimensioned so that the permissible tension of the repaired pipeline in the region of the fault is not exceeded when subjected to the maximum pressure, ie the maximum value of the operating pressure of the pipeline.
• an elongation of the pipe is determined due to the pressure difference between the lowered pressure and the maximum pressure of the medium, which is used to determine such a number of winding layers of the bandage, with which at least the same elongation at the same specified safety upper limit of the clamping ⁇ tion of the pipeline corresponding tension of the bandage is achieved.
• the material of the pipe for example a Stahlle ⁇ Government, has, as mentioned, an inherent elasticity, which causes a corresponding expansion of the pipeline in radial direction depending on the media pressure. A pressure increase between the unloaded state of the pipeline, in which the pipeline is not exposed to a medium pressure, and the maximum pressure, causes a maximum value of the elongation of the pipeline.
• the medium pressure is lowered to a lower pressure level compared to the operating pressure.
• a bias which depends on the expansion behavior of the pipeline.
• the bias of the pipe is greater, the lower the pressure drop.
• the pressure differential causes the pipeline to stretch from the prestressed condition to the maximum of the expansion.
• a voltage is built up which, upon reaching the maximum pressure at least equal to the freezing and beauty ⁇ upper limit for the voltage in the pipeline.
• the rigidity of the bandage is here, as already described, influenced by the number of layers.
• the elongation of the pipeline is determined by means of a characteristic curve for the stress-strain behavior of the pipeline. It can therefore be read from the characteristic curve which stress state is caused by a certain elongation of the pipeline.
• the characteristic defines a safety upper limit of the voltage, which should not be exceeded.
• the safety and beauty upper limit of the voltage corresponding to the maximum value of the Deh ⁇ voltage between the unloaded state of the pipe and the maximum pressure in the pipeline.
• the expansion behavior of the pipeline is also determined as a function of the medium pressure.
• the strain can be determined, which is caused by the pressure difference between the lowered pressure and the maximum pressure.
• the bandage is then determined with which for the previously determined elongation of the safety upper limit of the voltage in the pipeline corresponding stress state is achieved.
• the curves for the stress-strain behavior can be implemented in a computer and possibly graphed who ⁇ .
• the number of layers is preferably determined by calculation.
• a defect present on the outside of the pipe is filled with a filler material, in particular an epoxy resin, before the pipe ⁇ line is wrapped in the region of the defect with the bandage.
• a filler material in particular an epoxy resin
• a high-strength filler is used, for which in particular certain epoxy resins are suitable.
• every wi creping the bandage is arranged as a dry fiber mat on the pipe, which is then impregnated with a matrix material, in particular an epoxy resin.
• a matrix material in particular an epoxy resin.
• the matrix material is applied over the entire surface of a winding layer before the next winding layer is wound around the pipe.
• the object underlying the invention is also achieved by a device of the type mentioned, in which the bandage depending on the pressure reduction of the medium in the area of the defect of the pipeline has a corresponding number of winding layers such that a tension of the bandage in the mounted state at a maximum pressure at least equal to the medium a fixed ⁇ defined safety limit a voltage of the pipeline in the area of the defect.
• At least one winding layer of Banda ⁇ ge in the mounted state substantially in the circumferential direction of the pipeline extending, unidirectional fibers, in particular carbon fibers having.
• forces can be optimally absorbed to the safety upper limit of the bandage, whereby a useful support effect can be achieved even at high operating pressures.
• the use of a carbon fiber-bandage with high tensile strength has been found to be low, which in particular has an HOE ⁇ here's modulus of elasticity than the ferrous alloy of the pipeline.
• At least one winding layer of the bandage extending substantially in the longitudinal direction of the pipeline unidirectional Fa ⁇ fibers, in particular carbon fibers, comprising.
• Preferably is used at least in an oriented in the longitudinal direction of the pipe winding layer when the wall thickness of the pipeline at the Be ⁇ area of the defect by more than 50%, for example in Wesent ⁇ union 80%, compared to an intact section of the conduit is reduced.
• the bandage from ⁇ changing a winding layer having substantially extending in the circumferential direction of the pipeline, unidirectional fibers and a winding layer having substantially in the longitudinal direction of the pipeline extending, unidirectional fibers is also advantageous if the bandage from ⁇ changing a winding layer having substantially extending in the circumferential direction of the pipeline, unidirectional fibers and a winding layer having substantially in the longitudinal direction of the pipeline extending, unidirectional fibers.
• an optimal load transfer both in the circumferential direction and in the longitudinal direction of the pipeline can be achieved.
• Figure 1 is a perspective view of a liquid or gas ⁇ medium-conducting pipeline, which was wrapped in the region of a defect with a bandage according to the invention, which has a corresponding number of winding layers of a fiber composite material depending on the pressure reduction in the pipeline.
• FIG. 2 shows a cross section of a part of the pipeline with bandage according to FIG. 1;
• Fig. 3 is a partially sectioned view of the pipe with bandage according to Figures 1, 2;
• FIG. 4 shows a longitudinal section of the pipeline with a bandage, which is arranged in the region of a defect present on the inner circumferential surface of the pipeline;
• 5 shows a longitudinal section of the pipeline with a bandage according to the invention, which is arranged in the region of a defect present on the outer lateral surface of the pipeline;
• 6 shows a longitudinal section of the pipeline with a bandage according to the invention, with which a defect in the form of an indentation is encased on the outer jacket surface of the pipeline;
• Fig. 7 is a section along the line VII-VII in Fig. 6;
• FIG. 8 shows a longitudinal section of the pipeline with an alternative embodiment of the bandage, which alternately has winding layers oriented in the circumferential direction or in the longitudinal direction of the pipeline;
• FIG. 9 shows an enlarged detail of the pipeline according to FIG. 8.
• FIG. 10 shows a stress-strain diagram, which contains a characteristic curve for the expansion behavior of the pipeline and curves for the expansion behavior of sleeves with different number of layers.
• a pipe 1 for transporting a liquid or gaseous medium which flows with an operating ⁇ pressure in the longitudinal direction 1 'of the pipe 1.
• the pipeline 1 is preferably designed as a pipeline, with which a liquid or gaseous medium, for example crude oil or natural gas, is transported.
• defects can occur in Be ⁇ drive 2, which weaken the pipe 1.
• the pipe 1 in the region of the defect 2 on a reduced wall ⁇ strength which is caused by a loss of material.
• the defect can 2 at a äuße ⁇ ren lateral surface 3 of the pipe 1 (see FIGS. 2, 3 and 5 to 9) or at an inner circumferential surface 4 of the pipe 1 (see. FIG. 4) occur.
• the pipe 1 is sheathed in the region of the defect 2 with a bandage 5 to the to support defective section of the pipeline 1.
• the bandage 5 a plurality of winding layers 6, which each consist of a fiber composite material.
• the bandage 5 has at least one winding layer 6 'with unidirectional fibers 7 oriented in the circumferential direction of the pipeline 1 in the mounted state. This high radial tensile forces can be absorbed.
• carbon fibers are provided.
• the flaw 2 extends to the inner Mantelflä ⁇ surface 4 of the pipe 1. In this case, no filler material 8 is required.
• a pipe 1 with a comparatively elongated ⁇ stretched flaw 2 can be seen.
• the axial extent of the bandage 5 is at least dimensioned such that the pipeline 1 is encased in the assembled state of the bandage 5 at least along the faulty spot 2.
• a pipe 1 is shown, in which a defect 2 in the form of a dent 2 'of the pipe 1 is present. In this case, no loss of material occurs. Such failures 2 can occur as a result of mechanical stresses.
• the indentation 2 ' is filled with filling material 8, in particular high-strength epoxy resin, before the bandage 5 is attached.
• the bandage 5 has a plurality of (three in the embodiment shown) winding layers 6 'with circumferentially oriented fibers 7 on.
• FIGS. 8, 9 show a defect 2 with massive loss of material, in which the wall thickness is reduced by more than 50% (substantially 80% in the illustrated embodiment).
• the drum 5 in this case at least one winding layer 6 'having Wesentli ⁇ surfaces in the longitudinal direction 1' of the pipeline 1 extending, unidi--directional fibers 7 '.
• a winding layers 6 'oriented alternately in the circumferential direction of the pipeline 1' and winding layers 6 "oriented in the longitudinal direction 1 'of the pipeline 1 are provided alternately.
• the bandage 5 each have three winding layers 6 'and three winding layers 6''on.
• a preferred method for repairing the defect 2 by means of the bandage 5 comprises at least the following steps.
• the pipe 1 in the area of the defect 2 ei ⁇ ner surface treatment preferably by means of sandblasting, subjected. If the flaw 2 extends on the outer lateral surface 3, as shown in Figures 2, 3, 5 to 9, the flaw 2 is then filled with filler 8.
• the required number of layers of the bandage 5 is determined, as will be explained below with reference to FIG. 10. From the number of layers and the outer diameter of the pipe 1, the required total length of the bandage 5 is determined, which is rolled up in the form of a dry fiber mat on a mounting roller.
• matrix material 9 is applied in the area of the defect 2 before a first Wick Ella ⁇ ge is wrapped around the pipe.
• the first winding layer 6 is smoothed, for example by means of a rubber spatula, to prevent blistering. Subsequently, the first winding ⁇ layer 6 is impregnated with matrix material 9, whereby the composite effect is produced. Depending on the number of layers, these operations are ent ⁇ Speaking repeated often. Here, a winding offset is avoided ⁇ the.
• the bandage 5 is wrapped with a linen tape, which for pressing out any air pockets and for solidifying the winding la gene 6 is stretched around the bandage 5. Thereafter, a release film is placed on the Banda ⁇ Ge 5. Finally, the bandage 5 is cured by means of a heating mat. The curing time is based on the temperature of the pipeline and the number of layers of the bandage 5.
• the pressure p of the medium flowing in the pipeline 1 is lowered from the operating pressure to a lower pressure p 1 before the bandage 5 is arranged at the defect 2.
• the number of winding layers 6 of the bandage 5 is determined as a function of the pressure reduction in the pipeline 1.
• a more RESIZE ⁇ ßere number of winding layers is provided, the lower the pressure drop in the pipeline, as will be explained below with reference to Fig. 10.
• a stress-strain diagram is shown, wherein on the vertical axis, the stress ⁇ in megapascals (MPa) and on the horizontal axis, the relative strain e in percent (%) is plotted.
• the diagram shows a characteristic curve 10 for the stress-strain behavior of the pipeline 1, which is made of a steel alloy. Due to the inherent elasticity of the pipeline 1, the medium pressure causes a corresponding expansion of the pipeline 1 in the radial direction.
• the characteristic curve 10 of the pipeline 1 in this case has a section 10 'in which the pipeline 1 is elastically deformable, so that there is a linear relationship between the stress ⁇ and the expansion e.
• the voltage o ⁇ max is set as a safety upper limit of the voltage, which must not be exceeded during operation of the pipe 1.
• the safety upper limit o ⁇ max of the voltage (225 N / mm 2 in the example shown) is reached at a maximum allowable operating pressure (hereinafter maximum pressure p max ) of the medium, which may be much greater than the operating ⁇ pressure of the medium, in turn is greater than the lowered pressure pi.
• maximum pressure p max maximum allowable operating pressure
• FIG. 10 also shows a characteristic curve 11 for the stress-strain behavior of a bandage 5 with a first, lower number of layers and a characteristic curve 12 for the stress-strain behavior of a bandage 5 with a second, higher number of layers ,
• the tensile rigidity of the bandage 5 is greater, the higher the number of winding layers 6. Accordingly, the characteristic curve 12 has a greater slope than the characteristic curve 11.
• the pipe 1 at the lowered pressure pi on an elongation which is the greater, the lower the pressure drop, which is in the embodiment shown 30% based on the operating pressure.
• the expansion ei of the pipeline 1 is determined, which corresponds to the pressure difference between the lowered pressure pi and the maximum pressure p max of the medium.
• the strain ei is less than the maximum value e 0 of the strain e. With a full ⁇ permanent interruption of medium flow strain ei just the maximum value e D e the strain would correspond.
• the number of layers of the bandage 5 is chosen so that the bandage 5 at the same elongation ei at least one of the safety upper limit o ⁇ max of the voltage of the pipeline 1 corresponding voltage ⁇ achieved.
• the bandage 5 according to characteristic curve 11 is for this purpose not ge ⁇ is suitable, since it is achieved i for the elongation El, a voltage o ⁇ wel ⁇ surface is substantially lower than the safety limit o ⁇ max the voltage ⁇ of the pipe 1.
• a bandage 5 is selected with a higher tensile stiffness, which reaches the desired state of stress at a given strain ei.
• the characteristic 12 be ⁇ writes such a bandage 5, in which an expansion ei ex ⁇ act causes the voltage corresponding to the safety upper limit o ⁇ max of the stress ⁇ of the pipe 1. All man- Cuffs 5 with a higher tensile stiffness than the characteristic curve 12 fulfill this condition. However, over-sizing of the bandage 5 would disadvantageously cause an increased load on the pipeline at the edge regions of the bandage 5. Accordingly, the bandage 5 is determined depending on the pressure drop from the characteristic field, which can be implemented in a computer. To select the bandage 5, moreover, the nature and extent of the defect 2 can be used. Thus, the spe ⁇ -specific requirements, any repair operation are taken into account with high accuracy for the selection of suitable bandage. 5 Of course, the number of layers determined on the basis of the criteria described above may vary considerably from the examples shown in FIGS. 1 to 9.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Pipe Accessories (AREA)

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Cited By (4)

Citations (8)

Family Cites Families (1)

• 2012
  • 2012-01-10 AT AT172012A patent/AT511828B1/de active
• 2013
  • 2013-01-09 WO PCT/AT2013/050006 patent/WO2013104010A1/fr not_active Ceased

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