CA2323555C - Multilayer plastic pipe and its use - Google Patents
Multilayer plastic pipe and its use Download PDFInfo
- Publication number
- CA2323555C CA2323555C CA002323555A CA2323555A CA2323555C CA 2323555 C CA2323555 C CA 2323555C CA 002323555 A CA002323555 A CA 002323555A CA 2323555 A CA2323555 A CA 2323555A CA 2323555 C CA2323555 C CA 2323555C
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- Canada
- Prior art keywords
- pipe
- layer
- barrier layer
- multilayer
- accordance
- Prior art date
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- Expired - Fee Related
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- 229920003023 plastic Polymers 0.000 title claims abstract description 23
- 239000004033 plastic Substances 0.000 title claims abstract description 23
- 230000004888 barrier function Effects 0.000 claims abstract description 53
- 239000000463 material Substances 0.000 claims abstract description 34
- 238000010168 coupling process Methods 0.000 claims abstract description 13
- 230000001070 adhesive effect Effects 0.000 claims abstract description 12
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 11
- 239000001301 oxygen Substances 0.000 claims abstract description 11
- 230000008878 coupling Effects 0.000 claims abstract description 10
- 238000005859 coupling reaction Methods 0.000 claims abstract description 10
- 238000009792 diffusion process Methods 0.000 claims abstract description 9
- 229920003020 cross-linked polyethylene Polymers 0.000 claims abstract description 7
- 239000004703 cross-linked polyethylene Substances 0.000 claims abstract description 7
- 238000010438 heat treatment Methods 0.000 claims abstract description 7
- 239000010410 layer Substances 0.000 claims description 80
- 239000012790 adhesive layer Substances 0.000 claims description 20
- 239000000853 adhesive Substances 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 9
- 210000002445 nipple Anatomy 0.000 claims description 8
- -1 polyethylene Polymers 0.000 claims description 7
- 239000004698 Polyethylene Substances 0.000 claims description 6
- 239000004715 ethylene vinyl alcohol Substances 0.000 claims description 6
- RZXDTJIXPSCHCI-UHFFFAOYSA-N hexa-1,5-diene-2,5-diol Chemical group OC(=C)CCC(O)=C RZXDTJIXPSCHCI-UHFFFAOYSA-N 0.000 claims description 6
- 229920000573 polyethylene Polymers 0.000 claims description 6
- 229920000219 Ethylene vinyl alcohol Polymers 0.000 claims description 4
- FPYJFEHAWHCUMM-UHFFFAOYSA-N maleic anhydride Chemical group O=C1OC(=O)C=C1 FPYJFEHAWHCUMM-UHFFFAOYSA-N 0.000 claims description 2
- 239000003190 viscoelastic substance Substances 0.000 claims 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 238000001816 cooling Methods 0.000 description 4
- 238000009826 distribution Methods 0.000 description 3
- 229920000098 polyolefin Polymers 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 239000002178 crystalline material Substances 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- 239000012080 ambient air Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 239000013013 elastic material Substances 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000010525 oxidative degradation reaction Methods 0.000 description 1
- 229920001748 polybutylene Polymers 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
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
- F16L33/00—Arrangements for connecting hoses to rigid members; Rigid hose connectors, i.e. single members engaging both hoses
- F16L33/01—Arrangements for connecting hoses to rigid members; Rigid hose connectors, i.e. single members engaging both hoses adapted for hoses having a multi-layer wall
-
- 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
- F16L9/00—Rigid pipes
- F16L9/12—Rigid pipes of plastics with or without reinforcement
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Laminated Bodies (AREA)
- Rigid Pipes And Flexible Pipes (AREA)
Abstract
The invention relates to a multilayer plastic pipe (1), preferably for use i n heating systems. The multilayer pipe comprises an inner core (2) and a barrier layer (6) surrounding the core and preventing oxygen diffusion through the multilayered pipe. The core (2) is made of a material having viscoelastic properties, preferably cross-linked polyethylene, and the barrier layer (6) is surrounded by an outer layer (8) of a material having adhesive properties. The invention also relates to the use of a multilayer pipe for providing pip e couplings.
Description
MULTILAYER PLASTIC PIPE AND ITS USE
FIELD OF THE INVENTION
The present invention relates to a multilayer plastic pipe, preferably intended for water piping in central heating systems. The multilayer pipe comprises an inner core and an outer barrier layer which is surrounding the inner core and is made of a material which prevents oxygen diffusion through the multilayered pipe. The invention also relates to the use of a multilayer plastic pipe.
BACKGROUND OF THE INVENTION
Plastic pipes have previously been used, for example, for water distribution. Such pipes are preferably made of polyolefins, such as cross-linked polyethylene (PEX), poly-propene or polybutylene. Plastic pipes which are to be used for water distribution in heating systems, such as for examp-le, those for floor heating or for radiator systems, must be provided with an oxygen barrier layer so as to prevent oxygen diffusion into the water and thus causing corrosion on the metal components which are part of the heating systems.
In order to prevent oxygen diffusion through the pipe, it is a commonly used method to coat the outer surface of the pipe with a barrier layer of a material which prevents diffu-sion, such as for example, ethylene vinyl alcohol (EVOH). An intermediate layer of an adhesive material, an adhesive layer, may be provided between the inner core and the barrier layer, said intermediate layer being effective to create or to increase the adhesion between the inner core, such as a PEX-pipe, and'the outer barrier layer.
An advantageous technique for connecting plastic pipes with different types of couplings and fittings in water dist-ribution systems is previously known, i.a. from SE-C2-500665 and SE-C2-501555. The described technique is used for pipe couplings for plastic pipes having viscoelastic properties, or memory properties, i.e. plastic pipes having a tendency to automatically shrink back to their original shape after, for instance, an expansion. A pipe material'having this property is, for example, cross-linked polyolefin, especially cross-linked polyethylene (PEX). The mechanical properties of the material allows a deformation of the pipe at temperatures as low as at least -20 C. In order to mount the plastic pipe on the pipe coupling, the end of the plastic pipe is expanded and a nipple is inserted into the expanded end of the pipe and is kept in the pipe until the pipe end shrinks back over the nipple. This known technique is advantageous as it is quick and easy to preform and provides a safe and water-tight coupling.
In accordance with the technique described above, the pipes are substantailly expanded in a radial direction. This has proven to function very satisfactorily when PEX-pipes are being used. However, this advantageous coupling technique is disadvantageous when it is used on pipes having an oxygen barrier layer as described above. In the process of an sub-statial, radial expansion of the pipe, cracks may appear in the outer barrier layer, said cracks occurring especially at low temperatures, such as temperatures below about 15 C. The cracks which occur in the barrier layer have shown a tendency to propagate into the pipe wall during the expansion process of the pipe, thus causing pipe fractures leading to leaking pipe couplings.
Attempts have been made to solve the above problem by modifying know barrier materials. The object has been to try to find modified barrier materials which may withstand an expansion without cracking. So far, a modified barrier mate-rial which provides an acceptable solution to the expansion cracking problem has not been found.
SUMMARY OF THE INVENTION
The object of the present invention is thus to provide a solution to the above problem, in that the advantageous coup-ling technique may be used on the plastic pipes which are specially made for use in heating systems.
FIELD OF THE INVENTION
The present invention relates to a multilayer plastic pipe, preferably intended for water piping in central heating systems. The multilayer pipe comprises an inner core and an outer barrier layer which is surrounding the inner core and is made of a material which prevents oxygen diffusion through the multilayered pipe. The invention also relates to the use of a multilayer plastic pipe.
BACKGROUND OF THE INVENTION
Plastic pipes have previously been used, for example, for water distribution. Such pipes are preferably made of polyolefins, such as cross-linked polyethylene (PEX), poly-propene or polybutylene. Plastic pipes which are to be used for water distribution in heating systems, such as for examp-le, those for floor heating or for radiator systems, must be provided with an oxygen barrier layer so as to prevent oxygen diffusion into the water and thus causing corrosion on the metal components which are part of the heating systems.
In order to prevent oxygen diffusion through the pipe, it is a commonly used method to coat the outer surface of the pipe with a barrier layer of a material which prevents diffu-sion, such as for example, ethylene vinyl alcohol (EVOH). An intermediate layer of an adhesive material, an adhesive layer, may be provided between the inner core and the barrier layer, said intermediate layer being effective to create or to increase the adhesion between the inner core, such as a PEX-pipe, and'the outer barrier layer.
An advantageous technique for connecting plastic pipes with different types of couplings and fittings in water dist-ribution systems is previously known, i.a. from SE-C2-500665 and SE-C2-501555. The described technique is used for pipe couplings for plastic pipes having viscoelastic properties, or memory properties, i.e. plastic pipes having a tendency to automatically shrink back to their original shape after, for instance, an expansion. A pipe material'having this property is, for example, cross-linked polyolefin, especially cross-linked polyethylene (PEX). The mechanical properties of the material allows a deformation of the pipe at temperatures as low as at least -20 C. In order to mount the plastic pipe on the pipe coupling, the end of the plastic pipe is expanded and a nipple is inserted into the expanded end of the pipe and is kept in the pipe until the pipe end shrinks back over the nipple. This known technique is advantageous as it is quick and easy to preform and provides a safe and water-tight coupling.
In accordance with the technique described above, the pipes are substantailly expanded in a radial direction. This has proven to function very satisfactorily when PEX-pipes are being used. However, this advantageous coupling technique is disadvantageous when it is used on pipes having an oxygen barrier layer as described above. In the process of an sub-statial, radial expansion of the pipe, cracks may appear in the outer barrier layer, said cracks occurring especially at low temperatures, such as temperatures below about 15 C. The cracks which occur in the barrier layer have shown a tendency to propagate into the pipe wall during the expansion process of the pipe, thus causing pipe fractures leading to leaking pipe couplings.
Attempts have been made to solve the above problem by modifying know barrier materials. The object has been to try to find modified barrier materials which may withstand an expansion without cracking. So far, a modified barrier mate-rial which provides an acceptable solution to the expansion cracking problem has not been found.
SUMMARY OF THE INVENTION
The object of the present invention is thus to provide a solution to the above problem, in that the advantageous coup-ling technique may be used on the plastic pipes which are specially made for use in heating systems.
This object has been achieved according to the invention by means of a multilayer plastic pipe having the characte-rizing features as defined in the claims.
The inventive solution provides the advantage that the advantageous coupling technique, which is quick, efficient and inexpensive, may be applied to a hole range of different pipes. This means that plumbers working with installations at the site do not require different couplings for different ty-pes of pipes, but may instead use just one type of couplings.
According to the invention the problem has been solved by coating the plastic multilayer pipe with an additional layer of an adhesive material, an adhesive layer. The ad-hesive layer may consist of the same or similar material as the intermediate adhesive layer which is applied between the inner core and the barrier layer so as to increase the ad-hesion between the layers. The inventive multilayer pipe which is coated with an outer adhesive layer can be radially expanded without crack formation occurring in the barrier layer or in other parts of the pipe wall.
In a plastic pipe having an outer layer, such as a bar-rier layer, stress concentrations naturally occur especially in the outer layer, when the pipe is expanded. Therefore, stress cracks appear mainly in the outer layer and these cracks may propagate, as described above, into the pipe wall during the expansion of the pipe and cause pipe fractures.
According to the invention the outer barrier layer is coated with an additional layer which in itself is sufficiently pliable to absorb stress concentrations and which also ad-heres to the brittle barrier layer such that this layer is "supported". This prevents or reduces the tendency to form cracks in the pipe wall.
The mechanical properties of crystalline materials, and also of semi-crystalline materials such as for example EVOH, depend among other things upon the crystalline structure of the material. The crystalline structure is dependent upon the rate of crystallisation, i.e. the cooling rate. On extrusion of a plastic pipe with a barrier layer, the outer layer is exposed directly to ambient air outside the extruder die. An extruded pipe with no additional outer layer is subjected to rapid cooling and crystallisation. On extrusion of a pipe ha-ving an outer adhesive layer according to the invention, the cooling of the barrier layer is slower and the thus obtained crystalline structure of said barrier layer has improved mechanical properties.
The barrier layer of a pipe with no additional outer layer is directly exposed to air when it leaves the extruder die at a temperature of above 200 C. An oxidative degradation of the barrier layer takes place at this stage which deteri-orates the mechanical properties of the material. In a pipe coated with an additional layer outside the barrier layer according to the invention, the outer layer protects the bar-rier layer against said degradation during the cooling period and therefor the mechanical properties of the barrier layer is improved.
BRIEF DESCRIPTION OF THE DRAWING
The invention is described in more detail below with re-ference to the accompanying drawing showing by way of example a preferred embodiment of the invention.
Figure 1 is a cross-sectional view of a multi-layer pipe according to the invention;
Figure 2 is an axial cross-section of an expanded multilayer pipe according to Figure 1 with an inserted nipple; and Figure 3 shows the multilayer pipe according to Figure 2 which shrinks over the nipple.
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 illustrates a cross-section of a preferred em-bodiment of a multilayer plastic pipe in accordance with the invention. The multilayer pipe 1 comprises an inner core 2 which is made of cross-linked polyolefin, preferably a cross-linked polyethylene, a PEX-pipe. The inner core 2 is made of a material having viscoelastic or memory properties, i.e. a material which after expansion tends automatically to retain to its original shape.
A barrier layer 6 is arranged on the outside of the in-ner core 2 in order to prevent oxygen diffusion through the pipe 1. The material of the barrier layer 6 is preferably ethylene vinyl alcohol (EVOH), which is a material which is commonly used as an oxygen barrier. Different modified va-riants of EVOH may also be used as barrier layers. Other known barrier materials preventing oxygen diffusion through the pipe may also be used as barrier layer within the scope of the invention.
The barrier layer 6 is arranged outside the inner core 2, preferably and in the embodiment of Figures 1-3, with an intermediate layer 4 between the barrier layer 6 and the in-ner core 2 of an adhesive material, an adhesive layer. The intermediate adhesive layer 4 is arranged in order to create or improve the adhesion between the inner core 2 and the bar-rier layer 6 of the multilayer pipe. The material of the adhesive layer may be any of the well know and easily avail-able products on the market having the property to adhere to the materials of the inner core 2 and the barrier layer 6.
The material of the adhesive layer is preferably a modified polyethylene, such as for example a maleic anhydride modified polyethylene.
According to the invention, an additional layer 8 is ar-ranged on the outside of the barrier layer 6. The outer layer 8 is an adhesive layer of the same or similar material to that of the intermediate adhesive layer 4 between the inner core 2 and the barrier layer 6. Within the scope of the in-vention, the material of the intermediate adhesive layer 4 and the outer adhesive layer 6, respectively, may of course consist of completely different materials having adhesive properties.
In accordance with a preferred embodiment of the in-vention, the wall thickness of the inner core 2 is about 1,5-25 mm, preferably about 1,8-5 mm, whilst the three outer layers 4, 6, 8 are relatively thin and have similar wall thicknesses. According to the preferred embodiment, the in-termediate adhesive layer 4 has a wall thickness of about 25-250 m, preferably 50-100 m, and the surrounding barrier layer 6 has a wall thickness of about 25-250 m, preferably 50-125 m. According to the preferred embodiment, the thick-ness of the outer adhesive layer 8 is about 25-250 m, pre-ferably 50-100 m.
Figure 2 illustrates an axial cross-section of the mul-tilayer pipe 1 according to Figure 1. The end part 10 of the pipe 1 has been expanded by an expander tool, which is not shown. A pipe coupling or a nipple 12, for example made of metal or plastic, is partly inserted into the expanded end 10 of the pipe.
An external lock ring, not shown, of elastic material, e.g. of the same material as the inner core, may be arranged on the outside of the end part 10 of the pipe as a reinforce-ment and may be expanded together with said end part 10.
Figure 3 illustrates how the expanded end part 10 of the pipe 1 tends to resume its original shape and shrinks onto the nipple 12. The pipe end 10 shrinks quickly and without external influence thus providing a safe and tight joint bet-ween the inside of the pipe end 10 and the outside of the in-serted part of the nipple 12.
The multilayer pipe 1 has a flexible outer layer 8 which adhere to the brittle barrier layer 6. The pipe end 10 may therefor be exposed to a rapid and substantial radial ex-tension, as illustrated in Figure 2, without crack formation or propagation occuring in any of the outer layers or in ot-her parts of the multi-layer pipe.
It will be understood that the invention is not rest-ricted to the aforedescribed and illustrated embodiment and that several modifications are conceivable within the scope of the following claims. In the illustrated embodiment a bar-rier layer is surrounded by an inner and an outer adhesive layer, respectively. It is understood, however, that the in-ner adhesive layer 4 may be omitted or optionally replaced by a modified barrier layer having properties which compensates the properties of the intermediate adhesive layer.
The inventive solution provides the advantage that the advantageous coupling technique, which is quick, efficient and inexpensive, may be applied to a hole range of different pipes. This means that plumbers working with installations at the site do not require different couplings for different ty-pes of pipes, but may instead use just one type of couplings.
According to the invention the problem has been solved by coating the plastic multilayer pipe with an additional layer of an adhesive material, an adhesive layer. The ad-hesive layer may consist of the same or similar material as the intermediate adhesive layer which is applied between the inner core and the barrier layer so as to increase the ad-hesion between the layers. The inventive multilayer pipe which is coated with an outer adhesive layer can be radially expanded without crack formation occurring in the barrier layer or in other parts of the pipe wall.
In a plastic pipe having an outer layer, such as a bar-rier layer, stress concentrations naturally occur especially in the outer layer, when the pipe is expanded. Therefore, stress cracks appear mainly in the outer layer and these cracks may propagate, as described above, into the pipe wall during the expansion of the pipe and cause pipe fractures.
According to the invention the outer barrier layer is coated with an additional layer which in itself is sufficiently pliable to absorb stress concentrations and which also ad-heres to the brittle barrier layer such that this layer is "supported". This prevents or reduces the tendency to form cracks in the pipe wall.
The mechanical properties of crystalline materials, and also of semi-crystalline materials such as for example EVOH, depend among other things upon the crystalline structure of the material. The crystalline structure is dependent upon the rate of crystallisation, i.e. the cooling rate. On extrusion of a plastic pipe with a barrier layer, the outer layer is exposed directly to ambient air outside the extruder die. An extruded pipe with no additional outer layer is subjected to rapid cooling and crystallisation. On extrusion of a pipe ha-ving an outer adhesive layer according to the invention, the cooling of the barrier layer is slower and the thus obtained crystalline structure of said barrier layer has improved mechanical properties.
The barrier layer of a pipe with no additional outer layer is directly exposed to air when it leaves the extruder die at a temperature of above 200 C. An oxidative degradation of the barrier layer takes place at this stage which deteri-orates the mechanical properties of the material. In a pipe coated with an additional layer outside the barrier layer according to the invention, the outer layer protects the bar-rier layer against said degradation during the cooling period and therefor the mechanical properties of the barrier layer is improved.
BRIEF DESCRIPTION OF THE DRAWING
The invention is described in more detail below with re-ference to the accompanying drawing showing by way of example a preferred embodiment of the invention.
Figure 1 is a cross-sectional view of a multi-layer pipe according to the invention;
Figure 2 is an axial cross-section of an expanded multilayer pipe according to Figure 1 with an inserted nipple; and Figure 3 shows the multilayer pipe according to Figure 2 which shrinks over the nipple.
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 illustrates a cross-section of a preferred em-bodiment of a multilayer plastic pipe in accordance with the invention. The multilayer pipe 1 comprises an inner core 2 which is made of cross-linked polyolefin, preferably a cross-linked polyethylene, a PEX-pipe. The inner core 2 is made of a material having viscoelastic or memory properties, i.e. a material which after expansion tends automatically to retain to its original shape.
A barrier layer 6 is arranged on the outside of the in-ner core 2 in order to prevent oxygen diffusion through the pipe 1. The material of the barrier layer 6 is preferably ethylene vinyl alcohol (EVOH), which is a material which is commonly used as an oxygen barrier. Different modified va-riants of EVOH may also be used as barrier layers. Other known barrier materials preventing oxygen diffusion through the pipe may also be used as barrier layer within the scope of the invention.
The barrier layer 6 is arranged outside the inner core 2, preferably and in the embodiment of Figures 1-3, with an intermediate layer 4 between the barrier layer 6 and the in-ner core 2 of an adhesive material, an adhesive layer. The intermediate adhesive layer 4 is arranged in order to create or improve the adhesion between the inner core 2 and the bar-rier layer 6 of the multilayer pipe. The material of the adhesive layer may be any of the well know and easily avail-able products on the market having the property to adhere to the materials of the inner core 2 and the barrier layer 6.
The material of the adhesive layer is preferably a modified polyethylene, such as for example a maleic anhydride modified polyethylene.
According to the invention, an additional layer 8 is ar-ranged on the outside of the barrier layer 6. The outer layer 8 is an adhesive layer of the same or similar material to that of the intermediate adhesive layer 4 between the inner core 2 and the barrier layer 6. Within the scope of the in-vention, the material of the intermediate adhesive layer 4 and the outer adhesive layer 6, respectively, may of course consist of completely different materials having adhesive properties.
In accordance with a preferred embodiment of the in-vention, the wall thickness of the inner core 2 is about 1,5-25 mm, preferably about 1,8-5 mm, whilst the three outer layers 4, 6, 8 are relatively thin and have similar wall thicknesses. According to the preferred embodiment, the in-termediate adhesive layer 4 has a wall thickness of about 25-250 m, preferably 50-100 m, and the surrounding barrier layer 6 has a wall thickness of about 25-250 m, preferably 50-125 m. According to the preferred embodiment, the thick-ness of the outer adhesive layer 8 is about 25-250 m, pre-ferably 50-100 m.
Figure 2 illustrates an axial cross-section of the mul-tilayer pipe 1 according to Figure 1. The end part 10 of the pipe 1 has been expanded by an expander tool, which is not shown. A pipe coupling or a nipple 12, for example made of metal or plastic, is partly inserted into the expanded end 10 of the pipe.
An external lock ring, not shown, of elastic material, e.g. of the same material as the inner core, may be arranged on the outside of the end part 10 of the pipe as a reinforce-ment and may be expanded together with said end part 10.
Figure 3 illustrates how the expanded end part 10 of the pipe 1 tends to resume its original shape and shrinks onto the nipple 12. The pipe end 10 shrinks quickly and without external influence thus providing a safe and tight joint bet-ween the inside of the pipe end 10 and the outside of the in-serted part of the nipple 12.
The multilayer pipe 1 has a flexible outer layer 8 which adhere to the brittle barrier layer 6. The pipe end 10 may therefor be exposed to a rapid and substantial radial ex-tension, as illustrated in Figure 2, without crack formation or propagation occuring in any of the outer layers or in ot-her parts of the multi-layer pipe.
It will be understood that the invention is not rest-ricted to the aforedescribed and illustrated embodiment and that several modifications are conceivable within the scope of the following claims. In the illustrated embodiment a bar-rier layer is surrounded by an inner and an outer adhesive layer, respectively. It is understood, however, that the in-ner adhesive layer 4 may be omitted or optionally replaced by a modified barrier layer having properties which compensates the properties of the intermediate adhesive layer.
Claims (15)
1. A multilayer plastic pipe comprising an inner core of a viscoelastic material, and a barrier layer surrounding the inner core and preventing oxygen diffusion through the multilayer pipe, wherein the multilayer pipe is radially expansible, and wherein the barrier layer is surrounded by an outer layer made of a first adhesive material, said adhesive outer layer forming the outermost layer of the multilayer pipe.
2. A multilayer pipe in accordance with claim 1, for use in heating systems.
3. A multilayer pipe in accordance with claim 1 or 2, wherein an intermediate layer of a second adhesive material is arranged between the inner core and the barrier layer.
4. A multilayer pipe in accordance with claim 3, wherein the wall thickness of the intermediate layer is 25-250 µm.
5. A multilayer pipe in accordance with claim 4, wherein the wall thickness of the intermediate layer is 50-100 µm.
6. A multilayer pipe in accordance with any one of claims 1 to 5, wherein the material of the barrier layer is ethylene vinyl alcohol.
7. A multilayer pipe in accordance with any one of claims 1 to 5, wherein the material of the barrier layer is a modified ethylene vinyl alcohol.
8. A multilayer pipe in accordance with any one of claims 1 to 7, wherein the first adhesive material is a modified polyethylene.
9. A multilayer pipe of claim 8, wherein said modified polyethylene is maleic anhydride modified polyethylene.
10. A multilayer pipe in accordance with any one of claims 1 to 9, wherein the wall thickness of the inner core is 1.5-25 mm, the wall thickness of the barrier layer is 25-250 µm, and the wall thickness of the outer adhesive layer is 25-250 µm.
11. A multilayer pipe in accordance with claim 10, wherein the wall thickness of the inner core is 1.8-5 mm, the wall thickness of the barrier layer is 50-125 µm, and the wall thickness of the outer adhesive layer is 50-100 µm.
12. A multilayer pipe in accordance with any one of claims 1 to 11, wherein at least one of said adhesive outer layer and said intermediate layer is a modified polyethylene, and said barrier layer is ethylene vinyl alcohol or a modified ethylene vinyl alcohol.
13. A multilayer plastic pipe in accordance with any one of claims 1 to 12, wherein said inner core is a cross-linked polyethylene.
14. A method for providing a pipe coupling by radial expansion of a plastic pipe and subsequent shrinking of the pipe onto a nipple, wherein the pipe is a multilayer plastic pipe comprising an inner core and a barrier layer surrounding the inner core and preventing oxygen diffusion through the multilayer pipe, and wherein the barrier layer is provided with an outer layer of a first adhesive material forming the outermost layer of the pipe.
15. A method in accordance with claim 14, wherein the multilayer pipe is provided with an intermediate layer of a second adhesive material between the inner core and the barrier layer.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9800967A SE511766C2 (en) | 1998-03-23 | 1998-03-23 | Plastic multilayer tubes and their use |
| SE9800967-3 | 1998-03-23 | ||
| PCT/SE1999/000429 WO1999049254A1 (en) | 1998-03-23 | 1999-03-18 | Multilayer plastic pipe and its use |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2323555A1 CA2323555A1 (en) | 1999-09-30 |
| CA2323555C true CA2323555C (en) | 2007-09-11 |
Family
ID=20410653
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002323555A Expired - Fee Related CA2323555C (en) | 1998-03-23 | 1999-03-18 | Multilayer plastic pipe and its use |
Country Status (11)
| Country | Link |
|---|---|
| US (1) | US6422269B1 (en) |
| EP (1) | EP1064487B2 (en) |
| AR (1) | AR018793A1 (en) |
| AT (1) | ATE305583T1 (en) |
| AU (1) | AU2866099A (en) |
| CA (1) | CA2323555C (en) |
| DE (1) | DE69927489T3 (en) |
| DK (1) | DK1064487T4 (en) |
| NO (1) | NO331863B1 (en) |
| SE (1) | SE511766C2 (en) |
| WO (1) | WO1999049254A1 (en) |
Families Citing this family (27)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7498509B2 (en) | 1995-09-28 | 2009-03-03 | Fiberspar Corporation | Composite coiled tubing end connector |
| US5921285A (en) | 1995-09-28 | 1999-07-13 | Fiberspar Spoolable Products, Inc. | Composite spoolable tube |
| US8678042B2 (en) | 1995-09-28 | 2014-03-25 | Fiberspar Corporation | Composite spoolable tube |
| GB2391600B (en) * | 2001-04-27 | 2005-09-21 | Fiberspar Corp | Buoyancy control systems for tubes |
| US7740077B2 (en) * | 2002-05-16 | 2010-06-22 | Wagon Trail Ventures, Inc. | Downhole oilfield tubulars |
| BR0310065A (en) * | 2002-05-16 | 2005-03-01 | Wagon Trail Ventures Inc | Tubular article, tubular article coating and method for preparing a tubular article and for producing well fluids |
| US7160593B2 (en) | 2002-07-23 | 2007-01-09 | Noveon, Inc. | Polyefinic pipe having a chlorinated polyolefinic hollow core |
| US7086421B2 (en) * | 2002-07-23 | 2006-08-08 | Noveon Ip Holdings Corp. | Crosslinked polyethylene pipe having a high density polyethylene liner |
| US7255134B2 (en) * | 2002-07-23 | 2007-08-14 | Lubrizol Advanced Materials, Inc. | Carbon black-containing crosslinked polyethylene pipe having resistance to chlorine and hypochlorous acid |
| FR2845453B1 (en) * | 2002-10-07 | 2004-11-26 | Nobel Plastiques | PIPELINE FOR THE TRANSPORT OF HYDROGEN-CONTAINING FLUIDS |
| WO2004065092A1 (en) * | 2003-01-22 | 2004-08-05 | Wellstream International Limited | Process for manufacturing a flexible tubular pipe having extruded layers made of crosslinked polyethylene |
| WO2005028198A1 (en) | 2003-09-19 | 2005-03-31 | Nkt Flexibles I/S | A flexible unbonded pipe and a method for producing such pipe |
| US7523765B2 (en) | 2004-02-27 | 2009-04-28 | Fiberspar Corporation | Fiber reinforced spoolable pipe |
| US20060281593A1 (en) * | 2005-06-09 | 2006-12-14 | Young John N | Clad surface arrow construction |
| US8187687B2 (en) | 2006-03-21 | 2012-05-29 | Fiberspar Corporation | Reinforcing matrix for spoolable pipe |
| US7644736B2 (en) * | 2006-05-26 | 2010-01-12 | Rehau, Inc. | PEX pipe for high pressure and high temperature applications |
| CA2619808C (en) | 2007-02-02 | 2015-04-14 | Fiberspar Corporation | Multi-cell spoolable pipe |
| US8746289B2 (en) * | 2007-02-15 | 2014-06-10 | Fiberspar Corporation | Weighted spoolable pipe |
| CA2641492C (en) | 2007-10-23 | 2016-07-05 | Fiberspar Corporation | Heated pipe and methods of transporting viscous fluid |
| CA2690926C (en) | 2009-01-23 | 2018-03-06 | Fiberspar Corporation | Downhole fluid separation |
| WO2011075538A1 (en) | 2009-12-15 | 2011-06-23 | Fiberspar Corporation | System and methods for removing fluids from a subterranean well |
| US8955599B2 (en) | 2009-12-15 | 2015-02-17 | Fiberspar Corporation | System and methods for removing fluids from a subterranean well |
| US8997880B2 (en) | 2012-01-31 | 2015-04-07 | Wagon Trail Ventures, Inc. | Lined downhole oilfield tubulars |
| WO2014026190A1 (en) | 2012-08-10 | 2014-02-13 | National Oilwell Varco, L.P. | Composite coiled tubing connectors |
| US8814333B1 (en) * | 2013-03-18 | 2014-08-26 | Xerox Corporation | Oxygen impermeable umbilicals for ink in a printer |
| WO2016026141A2 (en) | 2014-08-22 | 2016-02-25 | 5Elem Material Scientific (Jiangsu) Co., Ltd | Fracturing liquid delivery hose for recovery of shale oil and gas, and manufacturing method thereof |
| EP3763980B1 (en) | 2019-07-12 | 2023-06-07 | Uponor Infra Oy | Multilayered pipes, method of producing the same and method of welding two multilayered pipes |
Family Cites Families (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB897222A (en) † | 1958-09-03 | 1962-05-23 | Hoechst Ag | Pipe sections made of plastics and a method of making them |
| US3561493A (en) † | 1965-04-21 | 1971-02-09 | Paul Maillard | Composite tubes and method of manufacturing same |
| DE2236375A1 (en) † | 1972-07-25 | 1974-02-07 | Technoform Caprano U Brunnhofe | Plastic pipes for hot water - with polyolefin inner layer and polyamide outer layer |
| ES448091A1 (en) † | 1975-05-22 | 1977-07-01 | Grace W R & Co | Film laminates having a reirradiated layer |
| DK154615C (en) † | 1976-02-18 | 1989-05-22 | Montedison Spa | PROCEDURE FOR MANUFACTURING HOLE BODIES OF TWO OR MORE LAYERS |
| CA1145272A (en) † | 1979-11-28 | 1983-04-26 | Jerker Skarelius | Gaseous diffusion resistant article and method utilizing same |
| DE3047181A1 (en) † | 1980-12-15 | 1982-06-16 | Hoechst Ag, 6000 Frankfurt | PLASTIC PIPE WITH OXYGEN-COATING |
| DE3104161A1 (en) † | 1981-02-06 | 1982-08-19 | Siemens AG, 1000 Berlin und 8000 München | Plastics hose or plastics pipe for transporting corrosive media |
| DE3207742C2 (en) † | 1982-03-04 | 1986-07-24 | REHAU AG + Co, 8673 Rehau | Use of a multilayer plastic film as a peripheral covering layer for plastic pipes carrying hot water |
| US4420670A (en) † | 1982-03-05 | 1983-12-13 | Cincinnati Milacron Industries, Inc. | Control for dielectric heating in blow molding machine |
| DE3319515A1 (en) * | 1983-05-28 | 1984-11-29 | kabelmetal electro GmbH, 3000 Hannover | Pipeline for the transport of heated media |
| DE3319501A1 (en) † | 1983-05-28 | 1984-11-29 | Chemische Werke Hüls AG, 4370 Marl | HYDROLYSIS-RESISTANT, THERMOPLASTIC MOLDS |
| JPS6211644A (en) * | 1985-06-26 | 1987-01-20 | 株式会社クラレ | Laminate having excellent gas permeability resistance |
| ES2104347T3 (en) * | 1993-02-05 | 1997-10-01 | Nobel Plastiques | MULTILAYER CHANNEL OF PLASTIC MATTER. |
| SE9300365L (en) * | 1993-02-05 | 1994-08-01 | Wirsbo Bruks Ab | Method for establishing a pipe connection and for use in the process suitable pipe connection piece |
| SE501555C2 (en) | 1993-10-07 | 1995-03-13 | Wirsbo Bruks Ab | Process for expanding a pipe end as well as tools for carrying out the method |
| US5866214A (en) * | 1995-07-28 | 1999-02-02 | W. R. Grace & Co.-Conn. | Film backseamed casings therefrom, and packaged product using same |
| DE29606533U1 (en) † | 1995-09-07 | 1996-06-05 | Hewing GmbH, 48607 Ochtrup | Multi-layer plastic pipe |
| US5869573A (en) * | 1995-12-19 | 1999-02-09 | Sumitomo Chemical Company, Limited | Resin composition and shaped article having a layer comprising the same |
| WO1998043806A1 (en) † | 1997-03-29 | 1998-10-08 | Hewing Gmbh | Multi-layer plastic tube |
-
1998
- 1998-03-23 SE SE9800967A patent/SE511766C2/en not_active IP Right Cessation
-
1999
- 1999-03-18 CA CA002323555A patent/CA2323555C/en not_active Expired - Fee Related
- 1999-03-18 AU AU28660/99A patent/AU2866099A/en not_active Abandoned
- 1999-03-18 DE DE69927489T patent/DE69927489T3/en not_active Expired - Lifetime
- 1999-03-18 WO PCT/SE1999/000429 patent/WO1999049254A1/en active IP Right Grant
- 1999-03-18 AT AT99909464T patent/ATE305583T1/en active
- 1999-03-18 EP EP99909464A patent/EP1064487B2/en not_active Expired - Lifetime
- 1999-03-18 US US09/646,609 patent/US6422269B1/en not_active Expired - Lifetime
- 1999-03-18 DK DK99909464.2T patent/DK1064487T4/en active
- 1999-03-23 AR ARP990101258A patent/AR018793A1/en active IP Right Grant
-
2000
- 2000-09-22 NO NO20004752A patent/NO331863B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| WO1999049254A1 (en) | 1999-09-30 |
| CA2323555A1 (en) | 1999-09-30 |
| ATE305583T1 (en) | 2005-10-15 |
| US6422269B1 (en) | 2002-07-23 |
| DE69927489T2 (en) | 2006-07-13 |
| DE69927489T3 (en) | 2013-06-13 |
| EP1064487B1 (en) | 2005-09-28 |
| NO20004752L (en) | 2000-09-25 |
| EP1064487B2 (en) | 2013-02-13 |
| AR018793A1 (en) | 2001-12-12 |
| NO20004752D0 (en) | 2000-09-22 |
| DE69927489D1 (en) | 2005-11-03 |
| DK1064487T3 (en) | 2006-01-30 |
| SE511766C2 (en) | 1999-11-22 |
| SE9800967L (en) | 1999-09-24 |
| EP1064487A1 (en) | 2001-01-03 |
| AU2866099A (en) | 1999-10-18 |
| DK1064487T4 (en) | 2013-03-25 |
| SE9800967D0 (en) | 1998-03-23 |
| NO331863B1 (en) | 2012-04-23 |
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