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
  • F16L59/00—Thermal insulation in general
  • F16L59/14—Arrangements for the insulation of pipes or pipe systems
  • F16L59/16—Arrangements specially adapted to local requirements at flanges, junctions, valves or the like
  • F16L59/18—Arrangements specially adapted to local requirements at flanges, junctions, valves or the like adapted for joints
  • F16L59/20—Arrangements specially adapted to local requirements at flanges, junctions, valves or the like adapted for joints for non-disconnectable joints
• • 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
  • F16L59/00—Thermal insulation in general
  • F16L59/14—Arrangements for the insulation of pipes or pipe systems
  • F16L59/143—Pre-insulated pipes
• • 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
  • F16L59/00—Thermal insulation in general
  • F16L59/14—Arrangements for the insulation of pipes or pipe systems
  • F16L59/16—Arrangements specially adapted to local requirements at flanges, junctions, valves or the like
  • F16L59/166—Arrangements specially adapted to local requirements at flanges, junctions, valves or the like covering the end of an insulated section

Definitions

• the present invention relates to a method of manufacturing a pipeline comprising several pipe sections, and to a pipeline of this kind.
• each section comprises at least one inner medium-holding pipe, a jacket pipe surrounding the medium-holding pipe, and heat insulation located between the medium-holding and the jacket pipes.
• the pipeline sections are factory-made for particularly urban-district heating systems, in which case the medium-holding pipes may be made from a weldable material, preferably steel, and the jacket .pipe preferably from a plastics material, suitably a high-molecular ethylene plastics.
• the heat insulation between the medium-holding and the jacket pipes may consist of expanded urethane plastics.
• the joining-together of the pipe sections in the joints is carried out when the pipe sections have been deposited in a dug-out trench, which is to be refilled once the joining operation is finished.
• the deposited pipeline is exposed to attacks from external moisture as well as to mechanical stress .
• To ensure long-term function of the pipeline it is of outmost importance that such moisture is prevented from coming into contact with the medium-holding pipes, since in the long run moisture will cause corrosion damage and, consequently, leakage. In turn, this leads to expensive operational interruptions and to repair work and injury hazards to the personnel.
• the main object of the present invention is to reduce the risk that moisture spreads to the medium- holding pipe in case of water penetration.
• Another object of the invention is to reduce the risk mentioned above through simple and inexpensive measures.
• said end protection means which suitably are made from plastics and preferably from ethylene plastics, are subjected to a surface-treatment , e.g. a corona-discharge treatment and/or blazing.
• a surface-treatment e.g. a corona-discharge treatment and/or blazing.
• the end protection means could be subjected to a surface treatment involving alteration of the surface geometry, e.g. a mechanical and/or cutting treatment.
• the object of all these kinds of treatments is to increase the adherence by "roughing", to coarsen the plastic surface of the protection means that is oily by nature.
• the entire insulation in the pipe sections and the joints
• the end protection means will behave like continuous and undivided insulation and thus prevent penetration of water/moisture to the medium-holding pipes .
• the end protection means are applied in position prior to the joining-together operation, suitably in conjunction with the factory-manufacture of the pipe sections, these end protection means will both cover and protect the heat insulation located between the medium-holding and the jacket pipes.
• each medium-holding pipe away from the free ends of the associated jacket pipe and heat insulation may be reduced further, down to a few centimetres, without causing any risks of excessive heat effects on the heat insulation as the medium-holding pipes are being joined together by means of welding or brazing using a naked flame.
• the arrangement contributes positively to minimising the space occupied by the joint.
• An additional advantage of factory-mounted end protection means is that the heat insulation between the medium-holding and the jacket pipes remains in dry condition during storage, transportation, and deposition at the work site prior to the interconnection of the pipe sections to form the pipeline.
• the end-protection means jointly with the jacket pipe, prevent gases, primarily carbon dioxide present in the closed cells of the expanded plastics that form the heat insulation, from escaping from the insulating material and into the surrounding atmosphere. Should such escape of diffusion of gases occur, it would cause the heat insulation to tend to shrink with consequential deterioration of its heat-insulation properties .
• Fig 1 is a schematic and perspective view as seen obliquely from the front of a straight pipe section forming part of the pipeline in accordance with the invention and for the sake of clarity shown partly cut,
• Figs 2A and 2B are perspective and schematic views as seen obliquely from behind and from the front, respectively, of end protection means forming part of the pipeline in accordance with the invention
• Fig 3 is a schematic and perspective view as seen obliquely from the front of a part of a pipeline prior to the joining-together, and of some of the components used to join-together two neighbouring pipe sections,
• Fig 4 is a schematic view as seen obliquely from the front of the part of pipeline in Fig 3 while being joined together having mounted end protection means and joined- together medium-holding pipes
• Fig 5 is a longitudinal sectional view of essentially the same pipeline part as shown in Figs 3 and 4 after completion of the joining-together operation.
• Fig 6 is a longitudinal sectional view essentially corresponding to Fig 5 but showing an alternative embodiment of the end protection means.
• pipe sections 2 are to be interconnected at joints 3 to form a long pipeline intended particularly for urban-district heating systems and to be deposited in pipe trenches, not shown.
• each pipe section 2 are at least one, usually one, two or four inner medium-holding pipes 4 of a preferably weldable/solderable material, preferably steel or copper, for transportation of a heating medium such as hot or superheated water or steam, in the case of urban-district heating systems, or a cooling medium or any other medium that is to be insulated from heat/cold while being transported in the pipeline 1.
• a heating medium such as hot or superheated water or steam
• the medium- holding pipe 4 be manufactured from some other suitable material, such as plastics, that lends itself to being joined-together with the aid of suitably configured interconnection means.
• the jacket pipe 5 is made from a plastics material, preferably from a high-density ethylene plastics, PEHD. This material is stabilised with respect to thermal, chemical, and oxidising decomposition and other decomposition, and among other things it possesses high impact strength resistance and abrasive resistance also at low temperatures.
• the medium-holding pipe 4 and on the other the jacket pipe 5 is arranged the third component of the pipe section 2, viz. heat insulation 6, preferably consisting of a freon-free expanded urethane plastics possessing excellent heat- insulating properties, high mechanical strength and high ageing resistance.
• the pipe sections 2 including the medium-holding pipes 4, the jacket pipes 5 and the heat insulation 6 preferably are manufactured as assembled units in the factory, the heat insulation suitably being cast in place during the manufacture.
• the heat insulation 6 could be performed pipe insulations sections from the same material as the cast heat insulation or from some other material that is suitable for the purpose, such as glass wool or rockwool .
• the pipe sections 2 are transported for deposition in dug-out pipe trenches, not shown, wherein they are interconnected at the joints 3, see Figs 3, 4, and 5.
• the joints 3 are located in the area 7 between two neighbouring pipe sections 2 to be interconnected.
• the medium-holding pipe 4 of each one of the pipe sections 2 protrudes over a short distance t from the free ends 8 of the associated jacket pipe 5 and heat insulation 6.
• the opposing, free ends 9 of the medium-holding pipes 4 of the two pipe sections 2 are joined together in sealing relationship by means of welding, brazing or on any other way.
• a sealing sleeve 11 see Figs 3 and 5.
• the sealing sleeve 11 could be made from the same or from similar material as the jacket pipe 5, i.e. from a plastic material, such as high density ethylene plastics.
• the sealing sleeve 11 is pushed onto the jacket pipe 5 of one of the pipe sections 2 prior to the joining-together of the medium-holding pipes 4 and is centred above the joint 3 after the j oining-together .
• Filler and ventilation bores are then drilled or otherwise made in the sealing sleeve 11.
• a required amount of a suitable expandable cellular plastics is then filled into the space 10 via the filler bores, by machine or manually, the cellular foam rising and expanding inside the space 10 so as to fill it completely, see Fig 5.
• the filler and ventilation bores are then sealed up.
• the expanded cellular plastics could be of the same type as the heat insulation 6 arranged between the medium-holding and jacket pipes 4 and 5, respectively and form a heat-insulating 12 in the space 10 in the joint 3, making the entire pipeline thermally insulated.
• preformed pipe insulation sections or the like made from a suitable insulating material.
• the preformed sections are applied around the joined-together medium-holding pipes 4 in the space 10 before the sealing sleeve 11 is centred above the joint 3.
• end protection means 13 Prior to the above steps of joining together the medium-hoiding pipes 4 of the pipe sections 2, covering the joint 3 with the sealing sleeve 11 and filling the space 10 with heat insulation 12, end protection means 13, see Figs 2A, 2B and 6, to be described in more detail in the following, are applied at the joint 3 in the area of the free ends 8 of the jacket pipes 5 and the heat insulation 6 of the pipe sections 2.
• the end protection means 13 are manufactured from plastics, suitably ethylene plastics.
• the end protection means 13 preferably are applied already in conjunction with the factory- manufacture of the pipe sections 2 and thus they are so to speak part of the pipe sections as the latter are delivered to the site of use. In any case, the end protection means 13 must be applied/mounted prior to the interconnection of the medium-holding pipes 4 and the joining-together, ensuring that when positioned at the free ends 8 they are able once the joining-together operation is completed, to strongly adhere to and sealingly abut against both the heat insulation 6 of the associated pipe section 2 and the heat insulation 12 in the space 10 of the joint 3.
• the end protection means 13 could and should, particularly when made from such a comparatively "oily" plastics material as ethylene plastics, be subjected to surface treatment or surface machining operations before being mounted on the pipe sections 2.
• the surface treatment may consist of a corona discharge treatment, i.e. some type of spark machining treatment, or a blazing treatment, i.e. some type of naked- lame singeing, to which are subjected at least those faces, or parts thereof, of the end protection means 13 that are turned towards the heat insulation 6 and 12, so as to cause the oily ethylene plastics surface of the end protection means to "burn" and become rough in order to thus increase the adherence to the thermal insulations .
• a corona discharge treatment i.e. some type of spark machining treatment
• a blazing treatment i.e. some type of naked- lame singeing
• the surface treatment may consist of a mechanical or chemical alteration of the surface geometry of the end protection means, for instance in the form of channels, grooves, depressions, and so on, which also contributes to increasing the adherence to the thermal insulations 6 and 12.
• each end protection means 13 is formed with several through-holes the number of which corresponds to the number of medium-holding pipes 4 and any further alarm and/or communication pipes in each pipe section 2, in the present case shown in the drawing figures one hole 14.
• the hole has essentially the same shape and dimensions as part 15 of the medium-holding pipe 4 of the associated pipe section 2, which part protrudes a distance t into the joint space.
• each end protection means 13 has a periphery 16 that is adapted to and abut against the jacket pipe of the pipe section 2.
• each end protection means 13 is formed around its periphery 16 with a peripheral flange 17 extending essentially perpendicularly to the end protection means and in parallel with the jacket pipe 5 in order to be essentially concentric with that pipe.
• the flange 17 is designed for insertion into the jacket pipe 5 while sealingly abutting against the internal face of that pipe.
• a contractable tape or the like 18 may as a further safety measure be applied around the ends of the sealing sleeve 11 so as to extend somewhat in over the jacket pipe 5 of the associated pipe section 2, thus preventing water/moisture from seeping into the joint 3 in the area of the interface between the sleeve and the jacket pipes.
• Fig 6 shows an alternative embodiment of the end protection means according to Figs 2A and 2B, which is distinguished from that embodiment principally therein that the web between the periphery 16 and the hole 14 is not straight but formed with a shoulder 20. Owing to the enlarged area provided by the provision of such a shoulder, additionally increased adherence to the heat insulations 6 and 12 interiorly and exteriorly of the end protection means 13 is achieved.
• the shoulder 20 contributes to improving the sealing effect towards moisture penetration, since such preformed sections may be applied with their slots in staggered relationship.
• the arrangement highly prevents heat dissipation from the medium-holding pipes 4 via the staggered slot with consequential smaller heat losses and protection against over-heating of the joint 3 itself, such that it is not, and particularly not the sealing sleeve 11 and the contractable tapes 18, damaged by the effects of heat .

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Thermal Insulation (AREA)
• Lining Or Joining Of Plastics Or The Like (AREA)

Applications Claiming Priority (3)

Publications (1)

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Family Applications (1)

Country Status (4)

Families Citing this family (6)

Family Cites Families (6)

• 2000
  • 2000-05-29 SE SE0002006A patent/SE516544C2/sv not_active IP Right Cessation
• 2001
  • 2001-04-26 EP EP01928261A patent/EP1285194A1/en not_active Withdrawn
  • 2001-04-26 AU AU2001255119A patent/AU2001255119A1/en not_active Abandoned
  • 2001-04-26 WO PCT/SE2001/000889 patent/WO2001092776A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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