FR2542060A1 - ISOLATED HEAT CONDUCTIVE PIPE AND METHOD FOR MANUFACTURING THE SAME - Google Patents

Abstract

A. CONDUCTIVE HOSE INSULATED FROM THE HEAT AND PROCESS FOR MANUFACTURING IT. B. CHARACTERIZED IN THAT, BETWEEN LAYER 2 OF FOAM PRODUCT AND EXTERIOR TUBE-ENVELOPE 3 OF PLASTIC MATERIAL OR INSIDE THE WALL OF THIS ENVELOPE 3 OF PLASTIC MATERIAL IS PROVIDED A SHEET OF METAL 5 CLOSED ON IT- EVEN, GLUED TO ITS INNER SURFACE AND OR TO ITS EXTERIOR SURFACE WITH THE ADJACENT LAYER 2, 3, PREFERABLY A SHEET OF ALUMINUM COATED WITH COPOLYMER, AND THIS SHEET OF METAL 5 HAS ITS EDGES WHICH ARE COVERED 6 ASSEMBLIES PER GLUE. C. THE INVENTION APPLIES TO THE THERMAL INSULATION OF HEATING PIPES.

Description

Insulated conductor heat pipe and method for

to make it ".

  The invention relates to a conductive pipe insulated from heat, consisting of a metal inner tube through which an agent passes and having a corrugated wall of helical or annular shape, preferably a tube

  welded longitudinally, and by an outer tube made of

  a plastics material concentrically and remotely surrounding the inner tube, as well as a heat-insulating layer disposed between the inner and outer tubes and formed of polyurethane-based plastics material;

the state of foam.

  Such a conductive pipe is known from the DE-GM

78 16 809.

  This conductive pipe, which is delivered to the

  mounting in lengths from 6 to 14 meters with

  prepared for connection to reinforcements or also to be assembled together, is particularly suitable for branch connections,

  in the construction of heating systems

  tance, leading to individual consumers.

  The present invention aims to improve this known conductive pipe by preventing the foam product layer from being influenced by moisture and moisture.

  gas, without limiting the flexibility-of the conductive pipe.

2542 O 6

  To this end, the invention relates to a conductive

  of the type indicated above, which is characterized in that

  that between the layer of foam product and the tube-wrapper

  In the outer wall of plastic material or inside the wall of this plastic envelope there is provided a sheet of metal closed on itself, adhered to its inner surface and / or to its outer surface with the adjacent layer, preferably an aluminum foil coated with copolymer, and this sheet of metal has its

  overlapping edges assembled by gluing.

  Thanks to the closed leaf on itself, we avoid

  with certainty a diffusion of water vapor through the en-

  plastic pile in the layer of polyurethane

  thane, which excludes deterioration of the foam product due to penetration of moisture.

  moreover the advantage of also preventing

  gas flow from inside to outside; that is

  say that the gas used for cytogeny that is

  known under the trade name "Freon 12" -

  is maintained by the leaf inside the neck.

che foam product.

  It turned out that polyurethane foams

  over time have poor properties of

  because the cytogenic gas diffuses outwards through the cell membranes Since this gas, which is responsible for the good insulating properties of the polyurethane foam, is maintained by the sheet in the layer. of foam product, the pipe

  heat-insulated conductor is rendered fit, in accordance

  to the invention, to preserve for a long time

  its good insulation properties.

  Thanks to the bonding of the sheet with the adjacent foam product coiche or the material of the envelope, the thermally insulated conductive pipe also presents

  good flexibility, without the sheet tearing.

  2542 O * d w Another very important benefit of the sheet is

  in that a transfer of softening of the thermal material

  moplastic of the envelope in the heat insulation layer is prevented and thus it is excluded that the plastic envelope becomes fragile even during prolonged placement The bonding of the sheet of metal with the adjacent layers has the role of ensuring a good longitudinal water tightness,

of the conductive pipe.

  According to a preferred embodiment of the invention,

  Invention, several inner tubes are surrounded by an envelope, being isolated from each other, by

  Foam product Two tubes are advantageously

  in an envelope and are isolated from each other.

  Since the lead branch leads

  from the same main line to the most

  part of the time these are consumers of homes for a single family are relatively long

  short, the heat exchange that occurs between the

  born and the return is weak to the point of being negligible this embodiment thus makes it possible to reduce the

  stocks and the cost of transportation and laying.

  In order to optimally adjust the thicknesses of insulating layer, use, if necessary, an envelope having a cross section deviating from the circular shape In the case where two tubes are passed through an envelope, this one would present by

  example an elliptical cross-section

  For the casing, use is advantageously made of cross-linked low-pressure polyethylene. This material has a high mechanical strength, which limits in a very high

  large extent the risk of damage to the envelope.

  Crosslinkable polyethylene is advantageously used

to moisture.

  There is a particular advantage that the tube

254206 ê

  interior has a ring-shaped ripple, the distance between two consecutive hollows of the ripple

  being then between 10 and 60 mm The advantage of using

  The fact that the connecting technique is substantially simpler compared to a corrugated inner tube in the form of a helix. If it is located, for example, at the end of the inner tube. smooth tube portions, one can thus use an assembly technique or connection technique as for smooth tubes With a distance of 10 to 60 mm between two recesses of the corrugation, the flexibility of the tubular device is not yet limited and the compensation capacity of the inner tube for thermal expansion is still found

maintained.

  The invention also relates to a

  assigned to manufacture an insulated conductive pipe at

  heat having the particularities defined above

  This process is characterized in that, therefore,

  a corrugated metal tube unwinding a supply reel, it is provided with spacers, preferably a spacer propeller foam polyurethane, is formed around the tube and at a distance from that a sheet of metal extending lengthwise over the split tube with overlapping edges and which is provided on at least one of its surfaces with a coating of a copolymer, before closing the split tube; applying to the metal foil a polyurethane or polyisocyanurate foamable plastic mixture which, after the closure of the edges, fills the annular space between the metal tube and the foam.

  metal sheet formed into a tube, extrusion is applied

  on the metal strip an envelope of plastic material

  tick and glue under the effect of extrusion heat.

  the metal foil with the adjacent foam product layer and / or with the adjacent envelope, while simultaneously adhering the overlapping edges of the metal foil. According to this process, it is advantageous if the aluminum foil serves at the same time as a conveyor belt and as a mold for the foam that forms. The bonding of the foil with one of the two or preferably both layers The overlapping edges of the overlapping sheet are then bonded together at the extrusion heat. The overlapping edges of the sheet are then glued at the same time to each other. in order to allow to obtain a uniform wall thickness for

the insulating layer that is provided.

  According to a particularly advantageous embodiment

  the process according to the invention, it is wound in

  common with the spacer propeller one or more conductors

  distance warning devices for the inner tube, These

  warning drivers are used to signal and locate

  read the moisture that has penetrated the product layer

foam.

  The conductive pipe produced according to the process according to the invention is flexible, which allows it to be wound on conventional cable drums.

  proved advantageous, for reasons of trans-

  port and storage, to manufacture this type of pipe

  duct in lengths between 6 and 14 m For the production of such pipes, after hardening of the layer of foam product, the manufactured pipe is cut to obtain sections of predetermined length,

  remove from the end of the pipe, on a short Ion-

  the shell and the layer of foam product, and the tube ends thus released are prepared for connection to similar tube ends or to

smooth tubes.

  The invention will be better understood with the aid of

  description and accompanying drawings representing

  schematic way of the exemplary embodiments of the invention.

  FIG. 1 is a side sectional view of a conductive pipe insulated from heat; Figure 2 is a cross-sectional view of Figure 1; Figure 3 shows a flow diagram of the process for making a conductive pipe insulated from heat;

  Figures 4 and 5 are side sectional views of

  partial examples showing, on a larger scale,

  connecting devices for the conductive pipe.

  The conductive pipe-consists of an integral tube

  corrugated sheet 1, an insulating layer 2 made of polyurethane

  the state of foam and a tubular envelope 3 of polyethylene

  In order to obtain a uniform wall thickness of the insulating layer 2, it is provided that

  spacers 4 forming a propeller, polyurethane foam.

  Between the insulating layer 2 and the plastic envelope 3, an aluminum foil 5 has been placed, which is bonded both with the envelope 3 and with the

  insulating layer 2 by means of a copolymer coating.

  The aluminum foil 5 has a cover gasket

  6, on the extent of which the overlapping edges

  are also assembled by gluing.

  The aluminum foil 5 prevents a penetration of moisture into the insulating layer 2 as a result of a diffusion of water vapor and at the same time has the role of

  to prevent the cytogenic gas that is used for the poly-

  urethane out of the insulating layer 2 The conductive pipe shown is advantageously delivered, at the assembly station, in lengths of 6 to 14 meters and is connected thereto as a result of continuous pipe line instead

  of the inner tube 1 one can also mount two or more

  inner tubes in a common envelope; however, care must be taken to provide an insulating layer

between the tubes -

  The insulated conductive pipe is, however, quite

  xible to be rolled up as well as drums

  cables and be able to be laid as an electrical cable

  directly in trenches; As tube-

  envelope, there is shown an envelope of plastic material

  However, there is also the possibility of using

  envelope a tube of corrugated plastic material.

  This would increase the flexibility of the pipe obtained by assembling

  and at the same time ensure better fixation.

of this pipe in the ground.

  For the manufacture of such conductive pipes, it is possible to introduce an inner tube 1, 6 m long, for example, into a tube of plastics material 3, advantageously having a corrugated wall, by inserting spacers 4 as auxiliary means; the inner surface of the tube 3 is coated with a sheet of metal. The insulating layer 2 is obtained by introducing the constituents of the foam product into the annular space situated between the

tube 1 and the tube 3.

  However, it appears more economical to manufacture as shown in Figure 3 Here the inner tube 1 is moved from a feed drum 7 and is wrapped with the spacer 4 by means of a tangential winder 8 The

  aluminum foil 5 coated on both sides with copoly-

  mothers is drawn from a feed reel 9 and brought

  under the inner tube 1 in order to be formed progressively

  tube with overlapping edges On this sheet

  of aluminum 5, it is applied from a mixing device

  10 the mixture of plastic material suitable for

  brought to the state of foam and the aluminum foil is formed

  minium 5 in tube with overlapping edges.

8 2542060

  The tubular casing 3 is obtained by extrusion by means of an extruder 11, the extrusion heat being then used to bond the aluminum foil as well with the insulating layer 2 as with the plastic envelope 3 When the insertion of the foaming plastic mixture is regulated so that it has filled in the region of the extruder 11 the annular gap between the inner tube 1 and the sheet 5, at the same time gluing, under the effect of extrusion heat, also edges

  overlap with each other As a result of the ex-

  11, a water bath 12 has been arranged in which

  the plastic casing 3 is cooled.

  When using, for example,

  the envelope a polyethylene which is curable to moisture

  Due to the addition of silanes, the casing 3 is cured at the same time in the water bath 12 The conductive pipe insulated from heat when finished

  can then be wound on cable drums, partly

  from which we can then take the necessary lengths. However, it is advantageous to

  following the water basin 12, a saw 13, making it possible to separate

  directly the lengths that are needed.

  So, 15 detached members are taken by train

of rollers 14.

  When the inner tube 1 has a ring-shaped corrugation, after having withdrawn from the end

  insulation layer 2 and the envelope 3 with the aluminum foil

  5, the end of tube 1 is prepared for an assembly

  such that there remains at the end a zone of

  smooth (Figure 4) The smooth tube areas of the ex-

  pipe ends prepared for assembly are in-

  In this type of assembly, it has proved advantageous to use a corrugation forming rings, the distance between which is

  two neighboring hollows is at least 30 mm.

  The assembly constituting a heat-insulated conductive pipe using a helically corrugated inner tube I is effected by first screwing into the end of each of the inner tubes a threaded sleeve 17 (FIG. 5). provided with an external thread, by screwing on the end of one of the tubes a threaded sleeve 18 with an internal thread, then bringing the ends of the tubes closer to one another and screwing the sleeve 18 of the one of the tube ends on the other up

  obtain the position shown in Figure 5 The ex-

  tremities of the inner tube 1 are securely clamped between the sleeves 17 and 18 The threaded sleeve 18 comprises for the screwing movement a hexagonal portion 19

  to allow to act on it with a wrench.

  The sleeve 18 is finally welded or brazed with the tube

inside 1.

  Subsequent isolation of assembly locations

  corresponding to the description above is carried out according to

  the technique like for assembly tubes by doing

  pass over a coupling sleeve and fill it

  Foam product the annular space between the inner tube and this sleeve The sealing thereof vis-à-vis the outer casing is effected by means of

  a section of retractable pipe.

  In order to continuously manufacture the conductive pipe according to the invention with a corrugated outer tube, it is advantageous to operate as follows: a corrugated tube of finished plastic material, provided with a metal lining, and is slit in the longitudinal direction, and then introduced into the corrugated plastic tube and split the inner tube provided with spacers and the constituents of the foam product provided and the slot is closed

  longitudinal by bonding or soldering.

Claims (2)

R E V E N D I C A T IO N S   1) Conductive pipe insulated from heat, consisting of a metal inner tube through which an agent passes and having a corrugated wall of helical or annular shape, preferably a longitudinal welded tube.   and by an outer tube made of plastic material   concentrically and remotely rotating the inner tube, as well as a heat-insulating layer disposed between the inner and outer tubes and formed of   polyurethane-based plastic in the state of foam   conductive pipe characterized in that, between the   che (2) of foam product and the outer casing tube (3) of plastic material or inside the wall of this envelope (3) of plastic material is provided a sheet of metal (5) closed on itself bonded to its inner surface and / or outer surface with the   adjacent layer (2, 3), preferably an aluminum foil   copolymer-coated sheet, and said metal sheet (5) has its overlapping edges (6) assembled by bonding.   Conductive pipe according to claim 1, characterized in that two or more inner tubes (1) isolated from each other by foam product (2)   are surrounded by an envelope (3).   30) Conductive pipe according to any one of the   Claims 1 and 2, characterized in that the envelope   (3) has a cross section deviating from the circular shape.   4) Conductive pipe according to any one of   Claims 1 to 3, characterized in that the envelope   (3) consists of crosslinked low pressure polyvinylethylene. ) Conductive pipe according to any one of   Claims 1 to 4, characterized in that the   inner tubes (1) have an annular corrugation, the distance between two recesses of the corrugation being between 10 and 60 mm.   ) Method of manufacturing a conductive pipe   heat-insulated according to any one of the claims   1 to 5, characterized in that, starting from a corrugated metal tube unwinding a supply coil, one   it is equipped with spacers, preferably a propeller   based on foam polyurethane, a sheet of metal extending along the split tube with overlapping edges and provided on at least one of his   surfaces of a coating made of a copolymer, before   the split tube is applied to the metal foil a mixture of foaming plastic material based on   polyurethane or polyisocyanurate and which after   setting-edges filled with foam product the space annu-   between the metal tube and the metal foil formed into a tube, an envelope of plastic material is extrusion-coated onto the metal strip and the sheet of metal is glued under the effect of the heat of extrusion. adjacent layer of foam product and / or with the adjacent envelope, while simultaneously   edges of the sheet of metal overlapping.   Method according to claim 6, characterized in that one or more warning conductors are wound away from the inner tube in common with   the helix formed by the spacers.   ) Method according to one or the other of the claims   6 and 7, characterized in that after the hardening of the layer of foam product is carried out by cutting   obtaining conductive pipes of predetermined length   In this process, the shell and the layer of foam product are removed from the end of the pipes for a short length and the ends of the tubes thus freed are prepared for connection to ends of the tubes. similar or to smooth tubes.