GB2336885A - Multilayer pipe - Google Patents

Multilayer pipe Download PDF

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Publication number
GB2336885A
GB2336885A GB9809198A GB9809198A GB2336885A GB 2336885 A GB2336885 A GB 2336885A GB 9809198 A GB9809198 A GB 9809198A GB 9809198 A GB9809198 A GB 9809198A GB 2336885 A GB2336885 A GB 2336885A
Authority
GB
United Kingdom
Prior art keywords
layer
multilayer pipe
pipe according
barrier layer
protective layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9809198A
Other versions
GB9809198D0 (en
GB2336885B (en
Inventor
Michael Bull
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Glynwed Pipe Systems Ltd
Original Assignee
Glynwed Pipe Systems Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Glynwed Pipe Systems Ltd filed Critical Glynwed Pipe Systems Ltd
Priority to GB9809198A priority Critical patent/GB2336885B/en
Publication of GB9809198D0 publication Critical patent/GB9809198D0/en
Publication of GB2336885A publication Critical patent/GB2336885A/en
Application granted granted Critical
Publication of GB2336885B publication Critical patent/GB2336885B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16LPIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L9/00Rigid pipes
    • F16L9/14Compound tubes, i.e. made of materials not wholly covered by any one of the preceding groups
    • F16L9/147Compound tubes, i.e. made of materials not wholly covered by any one of the preceding groups comprising only layers of metal and plastics with or without reinforcement
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/09Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/12Articles with an irregular circumference when viewed in cross-section, e.g. window profiles
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/15Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor incorporating preformed parts or layers, e.g. extrusion moulding around inserts
    • B29C48/151Coating hollow articles
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/16Articles comprising two or more components, e.g. co-extruded layers
    • B29C48/18Articles comprising two or more components, e.g. co-extruded layers the components being layers
    • B29C48/21Articles comprising two or more components, e.g. co-extruded layers the components being layers the layers being joined at their surfaces
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2105/00Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/0097Glues or adhesives, e.g. hot melts or thermofusible adhesives
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2305/00Use of metals, their alloys or their compounds, as reinforcement
    • B29K2305/02Aluminium
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2995/00Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
    • B29K2995/0037Other properties
    • B29K2995/0065Permeability to gases
    • B29K2995/0067Permeability to gases non-permeable
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29LINDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2009/00Layered products
    • B29L2009/003Layered products comprising a metal layer
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29LINDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2023/00Tubular articles
    • B29L2023/22Tubes or pipes, i.e. rigid

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)
  • Laminated Bodies (AREA)

Abstract

The pipe 2, for carrying hydrocarbon materials, comprises an inner structural layer 4 formed from a plastics material; a metallic hydrocarbon-resistant barrier layer 8 disposed outwardly of the structural layer 2, the barrier layer 8 being less permeable to the passage therethrough of hydrocarbons than the structural layer 2; and a protective layer 12 disposed outwardly of the barrier layer; characterised in that the outer surface 12 of the pipe is formed from a conductive material. The layer 8 can be of aluminium foil. The outer layer 12 is a conductive polyethylene containing carbon black. The inner structural layer 4, e.g. HDPE, is extruded, the barrier layer 8 is wrapped around it, coated with adhesive on both sides, and the outer layer 12 applied by extrusion coating.

Description

2336885 1 IMPROVEMENTS IN OR RELATING TO PIPES This invention relates to
pipes, and in particular to pipes which are intended to carry hydrocarbons such as petrol.
Petrol supply installations such as petrol stations typically comprise a system of underground storage tanks, dispensing pumps, and supply and vent pipes, as well as other associated petrol forecourt equipment. The pipes or hoses used to connect the various components of such installations are often formed from plastics materials such as polyethylene, a barrier layer formed from a hydrocarbon resistant material such as a metal or a hydrocarbon impermeable polymer being provided to prevent petrol loss through the wall of the pipe.
It is an object of this invention to provide an improved pipe for carrying petrol and other hydrocarbon materials.
Accordingly, the invention provides a muitilayer pipe for carrying hydrocarbon materials, the pipe comprising an inner structural layer formed from a plastics material; a metallic hydrocarbon-resistant barrier layer disposed outwardly of the structural layer, the barrier layer being less permeable to the passage therethrough of hydrocarbons than the structural layer; and a protective layer disposed outwardly of the barrier layer; characterised in that the outer surface of the pipe is formed from a conductive material.
The inner structural layer typically is formed from a polyolefin such as polyethylene or polypropylene. The inne-r structural layer provides the structural strength of the pipe and typically can be from 2.5mm to 1 5mrn thick, more usually from 4mm to 1 2mm thick. The structural layer provides 2 containment but is not usually impermeable to hydrocarbons. Hydrocarbon barrier properties are provided by the metallic hydrocarbon-resistant barrier layer which is disposed outwardly of the inner structural layer.
The metallic hydrocarbon-resistant barrier layer is most preferably an aluminium foil layer which can be applied to the inner layer in continuous axial fashion or by winding in a spiral fashion about the inner layer so that there is continuous overlap along the length of the pipe.
The metallic hydrocarbon-resistant barrier layer is preferably adhesively bonded to the inner structural layer and to the protective layer. Suitable adhesives for this purpose are of the heat sensitive type, such as polyethylenes grafted with maleic anhydride or acrylic acid. In order to minimise the electrical insulating properties of the adhesive layer it is typically a relatively thin layer, for example less than 0.5mm thick, more usually less than 0.3mm thick.
The outer surface of the pipe is formed from a conductive material. The conductive outer surface of the pipe can be constituted by the protective layer or by a separate conductive layer coated onto the protective layer. It is preferred however that the protective layer is formed from a plastics material containing a conductive agent, or is formed from a conductive polymer so as to reduce resistance to the flow of charge between the metallic hydrocarbon-resistant barrJer layer and the outer surface of the pipe. The protective layer can be formed, for example, from a plastics material containing a conductive agent selected from metal fibres, metal powders and carbon black. In a preferred embodiment, the protective layer is formed from a polyolefin containing carbon black as the conductive agent. The conductivity of the protective layer is chosen such that typically it has a resistance of 10' ohms or less and more preferably 10' ohms or less. The protective layer is usually up to about 3mm thick, for example from 0.5 to 2mm thick, e.g. approximately 1 mm thick.
3 In a further aspect, the invention provides a method of making a multilayer pipe as hereinbef ore defined, the method comprising extruding the inner structural layer, wrapping a metallic hydrocarbon-resistant barrier layer about the extruded inner structural layer and forming the protective layer by extrusion coating onto the barrier layer.
The invention will now be illustrated by reference to one specific embodiment as shown in the drawings of which:- Figure 1 which is a schematic longitudinal sectional through a pipe according to the invention; Figure 2 is an isometric view of the pipe of Figure 1 with the various layers revealed; and Figure 3 is an enlarged view of the region marked A in Figure 2.
As shown in the Figures, the pipe 2 comprises a core layer 4 which is formed from HIDPIE. In this embodiment, the HDPE is pigmented with an orange-red pigment. Bonded to the core layer 4 by means of an adhesive layer 6 is a layer 8 of aluminium foil which is approximately 300 micron thick in this embodiment, although it can be thicker or thinner than this if required. The aluminium foil 8, pre-coated with adhesive on both sides, is wrapped about the core layer, the edges 8a and 8b (shown as a dotted line) overlapping to ensure that there is an axial overlap along the length of the pipe. The aluminium foil layer acts as a barrier to petrol.
As indicated above, the outer surface of the aluminium is also coated with an adhesive layer 10 which serves to bond the foil to the outer protective layer 12. The outer protective layer 12, which in this embodiment is approximately 1 mm thick, is formed from a conductive polyethylene containing carbon black as the conductive substance. The polyethylene 4 contains sufficient carbon black to reduce the resistivity of the outer layer to less than 10' ohm metres. A typical composition for the protective layer is pipe grade polyethylene, e.g. a medium density polyethylene such as MIDPE80, containing up to 15% conductive carbon black plus antioxidant additives.
The pipe is formed by extruding, calibrating and partially cooling the core PE layer in conventional fashion. This is followed by application of the aluminium foil (which is precoated with adhesive polymer on both sides) from a coil, using a wrapping machine consisting of a series of rollers and hot air blowers, which progressively apply and heat seal the foil to the core pipe. An overlapping heat sealed joint in the foil wrapping is formed in the axial pipe direction. Once the foil layer 8 has been applied, the outer protective layer 12 is applied by an extrusion coating method to the hot foil layer and adhesive. Thus, an annular die is employed to apply the extruded coating to the foil wrapped core pipe, a vacuum being applied under the annular extruded melt so that the coating layer 12 is drawn down onto the aluminium surface, giving a snug fit and adhesion to the exterior of the foil wrapped core. Following extrusion coating, the pipe 2 is spray cooled, marked and cut in conventional fashion.
The structure of the pipe 2 is such that any electrical energy, static or otherwise, within the aluminium layer is dissipated outwardly into the conductive outer layer 12 and thence into the surrounding earth. Although the adhesive layer 10 does have some insulating properties and hence does provide some resistance to the flow of electricity from the aluminium layer to the outer conductive layer, the overall resistance of the adhesive layer is low and it has a negligible effect on the earthing process. This is because the area of contact between the layers is very large (area for a 63mm OD pipe of 1 Om length is 2 square metres, for example) whereas the thickness of the adhesive layers is typically very small (e.g. less than 0.3mm).
The invention has been illustrated by reference to a pipe in which the outer protective coating contains carbon black as the conducting agent. However, other conductive polymer mixtures could be used instead of carbon black-filled polyethylene. For example, the conductive agent could be a metal powder or metal fibres instead of carbon black. Alternatively, a conductive polymer could be used.
It will readily be apparent that numerous alterations and modifications could be made to the embodiment illustrated in the drawings without departing from the principles underlying the invention, and all such modifications and alterations are intended to be embraced by this application.
6

Claims (1)

1 A multilayer pipe for carrying hydrocarbon materials, the pipe comprising an inner structural layer formed from a plastics material; a metallic hydrocarbon-resistant barrier layer disposed outwardly of the structural layer, the barrier layer being less permeable to the passage therethrough of hydrocarbons than the structural layer; and a protective layer disposed outwardly of the barrier layer; characterised in that the outer surface of the pipe is formed from a conductive material.
A multilayer pipe according to claim 1 wherein the inner structural layer is formed from a polyolefin.
A multilayer pipe according to claim 2 wherein the polyolefin is polyethylene or polypropylene.
4. A multilayer pipe according to any one of the preceding claims wherein the metallic hydrocarbon-resistant barrier layer is an aluminium foil.
A multilayer pipe according to claim 4 wherein the aluminium foil is wrapped about the inner structural layer.
6. A multilayer pipe according to any one of the preceding claims wherein the metallic hydrocarbon-resistant barrier layer is adhesively bonded to the inner structural layer.
7.
A muffilayer pipe according to any one of the preceding claims wherein the metallic hydrocarbon-resistant barrier layer is adhesively bonded to the protective layer.
8. A multilayer pipe according to any one of the preceding claims 7 wherein the protective layer is coated on its outer surface with a conductive medium.
A multilayer pipe according to any one of claims 1 to 7 wherein the protective layer is formed from a plastics material containing a conductive agent, or is formed from a conductive polymer.
10. A multilayer pipe according to claim 9 wherein the protective layer is formed from a plastics material containing a conductive agent selected from metal fibres, metal powders and carbon black.
11. A multilayer pipe according to claim 10 wherein the protective layer is formed from a polyolef in containing carbon black as the conductive agent.
12. A multilayer pipe according to any one of the preceding claims wherein the protective layer has a resistance of 10' ohms or less.
13. A multilayer pipe according to claim 12 wherein the resistance is 10' ohms or less.
14. A multilayer pipe substantially as described herein with reference to the accompanying drawings Figures 1 and 2.
15. A method of making a multilayer pipe as defined in any one of the preceding claims, the method comprising extruding the inner structural layer, wrapping a metallic hydrocarbon-resistant barrier layer about the extruded inner structural layer and forming the protective layer by extrusion coating onto the barrier layer.
16. A method of making a multilayer pipe substantially as described herein with reference to the accompanying drawings.
GB9809198A 1998-04-29 1998-04-29 Improvements in or relating to pipes Expired - Fee Related GB2336885B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9809198A GB2336885B (en) 1998-04-29 1998-04-29 Improvements in or relating to pipes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9809198A GB2336885B (en) 1998-04-29 1998-04-29 Improvements in or relating to pipes

Publications (3)

Publication Number Publication Date
GB9809198D0 GB9809198D0 (en) 1998-07-01
GB2336885A true GB2336885A (en) 1999-11-03
GB2336885B GB2336885B (en) 2002-11-13

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB9809198A Expired - Fee Related GB2336885B (en) 1998-04-29 1998-04-29 Improvements in or relating to pipes

Country Status (1)

Country Link
GB (1) GB2336885B (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2825773A1 (en) * 2001-06-06 2002-12-13 Ueponor Innovation Ab MULTILAYERED PIPE AND MANUFACTURING METHOD
EP1316751A3 (en) * 2001-11-29 2003-12-17 Europipes S.r.l. Multilayer pipe
DE10318328B3 (en) * 2003-04-19 2004-07-15 Uponor Innovation Ab Bonded plastic-metal tube for heating installation has plastic base tube with oxygen diffusion blocking layer on it and layer of bonding material on that, with metal band on it
US7976920B2 (en) 2003-09-19 2011-07-12 Nkt Flexibles I/S Flexible unbonded pipe and a method for producing such pipe
GB2588641A (en) * 2019-10-30 2021-05-05 Barnes Stephen Improved pipe liner and associated methods

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2332492A (en) * 1997-12-22 1999-06-23 Draftex Ind Ltd Multi-layer fuel pipe

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2825773A1 (en) * 2001-06-06 2002-12-13 Ueponor Innovation Ab MULTILAYERED PIPE AND MANUFACTURING METHOD
EP1316751A3 (en) * 2001-11-29 2003-12-17 Europipes S.r.l. Multilayer pipe
DE10318328B3 (en) * 2003-04-19 2004-07-15 Uponor Innovation Ab Bonded plastic-metal tube for heating installation has plastic base tube with oxygen diffusion blocking layer on it and layer of bonding material on that, with metal band on it
US7976920B2 (en) 2003-09-19 2011-07-12 Nkt Flexibles I/S Flexible unbonded pipe and a method for producing such pipe
US8163364B2 (en) 2003-09-19 2012-04-24 Nkt Flexibles I/S Flexible unbonded pipe and a method for producing such pipe
EP1663637B2 (en) 2003-09-19 2018-07-25 National Oilwell Varco Denmark I/S A flexible unbonded pipe and a method for producing such pipe
NO345496B1 (en) * 2003-09-19 2021-03-08 Nat Oilwell Varco Denmark Is Flexible, non-bonded pipe as well as method of making such a pipe
GB2588641A (en) * 2019-10-30 2021-05-05 Barnes Stephen Improved pipe liner and associated methods
GB2588641B (en) * 2019-10-30 2022-04-20 Flowlining Ltd Improved pipe liner and associated methods
US11796091B2 (en) 2019-10-30 2023-10-24 Flowlining Limited Pipe liner and associated methods

Also Published As

Publication number Publication date
GB9809198D0 (en) 1998-07-01
GB2336885B (en) 2002-11-13

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Legal Events

Date Code Title Description
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20130429