Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D23/00—Producing tubular articles
  • B29D23/001—Pipes; Pipe joints
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C31/00—Handling, e.g. feeding of the material to be shaped, storage of plastics material before moulding; Automation, i.e. automated handling lines in plastics processing plants, e.g. using manipulators or robots
  • B29C31/002—Handling tubes, e.g. transferring between shaping stations, loading on mandrels
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
  • B29C44/02—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles
  • B29C44/12—Incorporating or moulding on preformed parts, e.g. inserts or reinforcements
  • B29C44/1228—Joining preformed parts by the expanding material
  • B29C44/1242—Joining preformed parts by the expanding material the preformed parts being concentric
• • 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

Definitions

• the invention relates to a method and a device for the discontinuous production of thermally insulated pipes with a thermal insulation layer made of rigid polyurethane foam produced by foaming in the space between an outer pipe and an inner pipe, the pipes being centered and mechanically fixed in their position relative to one another before the foaming are and wherein at least one pullable mixing head is introduced into the intermediate space, which, when pulled out, ejects a reaction mixture forming a rigid polyurethane foam, which foams to form the thermal insulation layer, and a heat-insulated tube with a thermal insulation layer which fills the space between an outer tube and an inner tube and is produced by foaming made of rigid polyurethane foam.
• the problem is the elastic deflection of the pipes during the foaming process by its own weight. This resulted in an inhomogeneous thermal insulation layer when foaming depending on the condition of the inner and outer pipe. In other words, this was possibly of different thickness, which had a disadvantageous effect on the thermal insulation properties.
• the deflection due to the weight of the pipes is particularly unpleasant in the case of longer pipes, ie pipes over a length of about 6 m.
• the object of the invention is to provide a method and a device for producing heat-insulated pipes with a heat-insulating layer made of rigid polyurethane foam produced by foaming between an outer pipe and an inner pipe, and a heat-insulated pipe, the alignment of the two pipes themselves and with respect to one another faster and safer with less manual labor takes place so that the heat-insulated pipe produced in this way has improved insulation properties which are homogeneous over its length, and in particular in the case of longer pipes the deflection caused by its own weight is compensated for.
• this object is achieved by a method in which, prior to the foaming, both tubes are mechanically aligned, centered and fixed in position relative to one another about a common central axis.
• “Separately from one another” is to be understood here to mean that the alignment, centering and fixing at the location of the subsequent foaming, that is to say in a device in this regard, takes place independently of one another and acts on the two pipes which do not have any contact with one another External tube acted on from outside, and on the inner tube from the inside, so that the space to be foamed remains free.
• the inner tube is also adequately aligned with the outer tube by avoiding or compensating for deflections.
• the deflections caused by storage and transport can be aligned linearly before processing, which is, of course, an additional work step.
• the pipes or their deviations from an imaginary linear center line can also be measured before being introduced into the device for foaming, and then deformations existing in the foaming device can be compensated for by means of a program control. Otherwise, the new method is centering, aligning and fixing as
• Align and center accomplish this, for example, by touch-free scanning of the positions, in particular of the inner tube, at certain measuring points and the action of the alignment elements based thereon.
• the outer tube is preferably centered, aligned and fixed from the outside by means of supporting surfaces.
• support surfaces are preferably attached to the pipe ends or near the pipe ends.
• the outer tube is centered and aligned in its position at its ends, and in particular with longer tube lengths, additional support surfaces that can be attached over the length of the outer tube ensure exact alignment and positioning of the tube. It goes without saying that the support surfaces assigned to the ends can be so far away from them that there is no longer any deflection in the case of short outer tubes between them. In order for larger ones
• the outer tube To avoid bending in the middle area of the outer tube, it is aligned and supported at a sufficient number of points. In extreme cases, the outer tube is supported continuously over its entire length. In addition to avoiding or eliminating deflections, the support surfaces serve as a counter pressure bearing for the foaming pressure that occurs during foaming.
• the inner tube is preferably centered, aligned and fixed at its ends by clamping holders.
• Alignment is carried out by applying a bending moment which compensates for existing deflections, for which purpose the deflection is carried out by mechanical scanning or scanning with rays, and depending on this, a counter-bending is generated until both tubes are aligned linearly.
• tensioning elements are introduced into the ends of the inner tube, optionally in addition to tensioning holders, and each of them is arranged at least 0.1 m from the associated tube end, and by means of these tensioning elements, the inner tube is centered, aligned and fixed.
• the spacing of the centering elements from the pipe ends is to be set such that any unwanted deflections that are created with them for alignment are compensated for.
• a prefabricated spacer is preferably made before foaming
• Rigid polyurethane foam is arranged in the space and this space is foamed with two counter-rotating mixing heads.
• this spacer is made of rigid foam with preferably the same inherent shade as the remaining thermal insulation layer produced by foaming, it is essentially homogeneous in an advantageous manner compared to conventional spacers used in the intermediate space, which consist of materials other than the rigid polyurethane foam thermal insulation layer the insulation properties of the thermal insulation layer achieved. It is particularly advantageous, however, that by inserting such a spacer, the tube length is quasi halved with regard to the inherent deflection, because at the point below the rigid foam core, the tubes can be jointly supported from below so that the inherent deflection can be compensated for by pressing up.
• the linear alignment at this point can be achieved, for example, by means of a light barrier, which is placed on the upper outer edge of the envelope. tube responds and at the appropriate time aborts the process of pushing up the support device.
• the distance between the outer tube and inner tube is preferably maintained by the mixing head.
• the outer circumference of the mixing head or a part of it designed as a spacer is matched to the outer diameter of the inner tube and the inner diameter of the outer tube in such a way that it fulfills the function of a spacer on the one hand and can be pulled out of the intermediate space without significant additional effort when foaming .
• the expelled, rapidly foaming reaction mixture then ensures that the correct distance between the tubes is maintained.
• This design of the mixing head is particularly advantageous if the outer tube consists of a less dimensionally stable polyethylene sheath.
• Brackets for the pipes and at least one mixing head that can be pulled through the intermediate space to produce the thermal barrier coating.
• the two tubes can be centered, aligned and fixed independently of one another about a common central axis.
• structures serve all of these processes, more or less simultaneously.
• This has the advantage that there is no need to insert spacers in the narrow space between the tubes, which would also represent undesirable thermal bridges. Since the alignment process of the two pipes takes place independently of one another, the elimination through the previous storage of any existing bends is possible more precisely. In particular, a deflection occurring in the device due to the weight of the pipes can be compensated.
• Support surfaces are preferably arranged as alignment elements towards the outside of the outer tube near each tube end.
• Such additional support surfaces are particularly advantageous for long pipes. They are designed so that they participate in the alignment. Another one
• the support surfaces preferably consist of prisms.
• prisms make it possible, to a certain extent, to process outer tubes of different diameters on the same device.
• tensioning elements which are movable, in particular pivotable, are provided for the tube ends of the inner tube as alignment elements for generating a bending moment transversely to the central axis.
• centering, aligning and fixing in the end position run more or less simultaneously, through the action of these appropriately designed clamping elements.
• tensioning elements which can be inserted into the inner tube are provided as alignment elements and can be moved transversely to the central axis in order to generate a bending moment.
• both the clamping holders for the pipe ends and the clamping elements that can be inserted into the inner pipe are advantageously designed, for example, as clamping blocks with a spreading effect.
• two counter-rotating mixing heads are provided.
• the mixing head itself is designed as a spacer.
• the new thermally insulated pipe is based on a thermal insulation layer made of rigid polyurethane foam and arranged in the space between an outer pipe and an inner pipe.
• Foaming placed spacers placed on half the length of the tube, which spacer consists of rigid polyurethane foam.
• this spacer does not necessarily have to be half length. However, this is advantageous because on the one hand the distance at the
• the prefabricated spacer should consist at least approximately of the same rigid polyurethane foam as the thermal insulation layer produced from the reaction mixture, because the insulation properties are then the same. At least theoretically, before
• Foaming also several prefabricated from rigid polyurethane foam
• FIG. 2 shows the device with a double tube according to FIG. 1, namely with a spacer, two mixing heads and the reaction mixture foaming to form a thermal barrier coating
• FIG. 3 shows a section along line A-B in FIG. 1,
• FIG. 4 shows a section along line C-D in FIG. 1.
• the device consists of individual, but coordinated alignment and fixing elements 1, 2, 3, 4, which are functionally assigned to an outer tube 5 made of polyethylene and an inner tube 6 made of steel. Both tubes 5, 6 have a common central axis 7. To the desired bending moments on the
• alignment and fixing elements 1, 2, 3, 4 can be pivoted and fixed transversely to the central axis 7.
• the alignment and fixing elements 1, 2 of the outer tube 5 can engage on the outer side 8 of the outer tube 5 and consist of support surfaces 1, 2 designed as prisms 1, 2. Of which the prisms 1 are assigned to the ends 9 of the outer tube 5, the prisms 2 as further support surfaces
• the alignment and fixing elements 3, 4 of the inner tube 6 consist of clamping brackets 3 which engage the tube ends 10 of the inner tube 6 and (or or) clamping elements 4 which engage in the inner tube 6 at a distance from the tube ends 10
• the space between the outer tube 5 and the inner tube 6 is designated by 11.
• Two mixing heads 12, 13 are provided with a device, not shown, for supplying polyurethane reaction components connected. These mixing heads 12, 13 can be moved into the intermediate space 11 in opposite directions. They are therefore simultaneously pulled out in the opposite direction and thereby expel a polyurethane reaction mixture 14.
• a prefabricated spacer 16 made of rigid polyurethane foam is arranged in the intermediate space 11 over half the length of the tube and has the same thermal insulation properties as the remaining thermal insulation layer 15 produced by foaming.
• Spacers made of rigid polyurethane foam are on hand and their functionality is easy to understand.
• the mixing head is placed at one end of the space to be foamed and pulled through it when the space is foamed. It is understood that the end sides of the space are preferably sealed to prevent contamination of the

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Robotics (AREA)
• Thermal Insulation (AREA)
• Rigid Pipes And Flexible Pipes (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=7896901

Family Applications (1)

Country Status (6)

Families Citing this family (11)

Family Cites Families (3)

• 1999
  • 1999-02-09 DE DE1999105275 patent/DE19905275A1/de not_active Withdrawn
• 2000
  • 2000-02-01 WO PCT/EP2000/000784 patent/WO2000047387A1/de not_active Application Discontinuation
  • 2000-02-01 EP EP00909130A patent/EP1152879A1/de not_active Withdrawn
  • 2000-02-01 PL PL00350578A patent/PL350578A1/xx unknown
  • 2000-02-01 AU AU31520/00A patent/AU3152000A/en not_active Abandoned
• 2001
  • 2001-07-19 NO NO20013567A patent/NO20013567D0/no not_active Application Discontinuation

Non-Patent Citations (1)

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