Pipe Fitting

1 . A multi-layer flexible pipe for conveying a target fluid, comprising:

at least one barrier layer of polyamide-12 (PA-12), for providing internal fluid integrity.

2 . The multi-layer flexible pipe as claimed in claim 1 further comprising:

a core layer arranged to provide an inner bore along which a fluid can flow.

3 . The flexible pipe as claimed in claim 1 or claim 2 wherein the barrier layer has sufficient ductile and fracture toughness properties to ensure that the flexible pipe will be flexible enough to be located at a desired location and to perform adequately at that location for twenty or more years, for a given cumulative temperature and chemical exposure.

4 . The flexible pipe as claimed in claim 3 wherein the barrier layer has a Corrected Inherent Viscosity of greater than 1.0 dl/g, for twenty or more years in operation, for a given cumulative temperature and chemical exposure.

5 . The flexible pipe as claimed in claim 3 wherein the barrier layer has a Corrected Inherent Viscosity of greater than 1.2 dl/g, for twenty or more years in operation, for a given cumulative temperature and chemical exposure.

6 . The flexible pipe as claimed in claim 5 wherein said barrier layer is an extruded layer.

7 . The flexible pipe as claimed in claim 6 wherein said barrier layer is a variety of Polyamide-12.

8 . The flexible pipe as claimed in claim 6 wherein said barrier layer is a Polyamide-12 modified with a flexibilising component

9 . The flexible pipe as claimed in claim 8 wherein said flexililising component is a liquid plasticiser.

10 . The flexible pipe as claimed in claim 9 wherein said plasticiser component is N-butylbenzenesulphonamide (BBSA).

11 . The flexible pipe as claimed in claim 10 wherein said barrier layer is a layer of Degussa BS0725.

12 . The flexible pipe as claimed in claim 10 wherein the barrier layer is a layer of Vestamid LX9020.

13 . The flexible pipe as claimed in claim 1 wherein said barrier layer comprises a barrier polymer layer.

14 . The flexible pipe as claimed in claim 1 wherein said target fluid comprises crude oil.

15 . The flexible pipe as claimed in claim 13 wherein said target fluid comprises a gas.

16 . The flexible pipe as claimed in claim 13 wherein said target fluid comprises export oil.

17 . The flexible pipe as claimed in claim 1 wherein said barrier layer comprises a bore-fluid retaining layer.

18 . The flexible pipe as claim 2 , wherein said barrier layer directly surrounds the core layer:

19 . The flexible pipe as claimed in claim 1 wherein said multi-layer flexible pipe has three or more layers.

20 . The flexible pipe as claimed in claim 1 wherein said barrier layer provides a layer with a high chemical resistance.

21 . The flexible pipe as claimed in claim 1 wherein said flexible pipe comprises a non-bonded flexible pipe.

22 . The flexible pipe as claimed in claim 1 wherein said core layer comprises a collapse-resistant layer.

23 . The flexible pipe as claimed in claim 1 wherein said barrier layer comprises a fluid barrier layer.

24 . The flexible pipe as claimed in claim 1 further comprising:

at least one tensile strength layer; and

at least one external fluid barrier layer.

25 . The flexible pipe as claimed in claim 1 wherein the barrier layer is an innermost polymer extruded layer located beneath a hoop strength layer.

26 . The flexible pipe as claimed in claim 1 wherein the barrier polymer layer comprises one layer of a multi-layer barrier layer.

27 . The flexible pipe a claimed in claim 26 wherein the multi-layer barrier layer comprises one or more layers of a further barrier material.

28 . The flexible pipe as claimed in claim 1 wherein said barrier polymer layer has a melting point of more than 170c.

29 . A multi-layer flexible pipe for conveying a target fluid, comprising:

at least one barrier polymer layer of polyamide-12, for providing internal fluid integrity.

30 . The multi-layer flexible pipe as claimed in claim 1 , comprising:

said barrier layer is formed from a polyamide-12 material formed from a process in which a salt of a weak acid is introduced during a step of condensing polyamides to increase the molecular weight to thereby nullify acid formed in an earlier stage.

31 . A method for providing a multi-layer flexible pipe for conveying a target fluid comprising the steps of:

providing at least one barrier layer of polyamide-12 (PA-12) for providing internal fluid integrity.

32 . The method as claimed in claim 31 further comprising the steps of:

providing a core layer having an inner bore along which a target fluid can flow.

33 . The method as claimed in claim 31 or claim 32 further comprising the steps of:

melting polyamide-12 in a food hopper;

providing the melted polymer at a crosshead chamber; and

forming a barrier layer of polyamide-12 in said crosshead.

34 . The method as claimed in claim 33 further comprising the steps of:

directing polyamide-12 from said feed hopper to said crosshead via a rotating screw and associated barrel.

35 . The method as claimed in claim 34 further comprising the steps of heating a throat region of the barrel to between 170° C. and 190° C.

36 . The method as claimed in claim 35 further comprising the steps of heating a remaining region of the barrel to between 210° C. and 230° C.

37 . The method as claimed in claim 36 further comprising the steps of heating the crosshead chamber to a temperature in the range of 210 20 C. to 230° C.

38 . The method as claimed in claim 37 further comprising cooling an extruded barrier layer exiting the crosshead chamber via a plurality of cooling baths.

39 . The method as claimed in claim 38 wherein the temperature of each cooling bath is maintained in the temperature range of between 20□c to 40° C.

40 . The method as claimed in claim 31 wherein said barrier layer is Polyamide-12 modified with a flexibilising component.

41 . The method as claimed in claim 40 wherein said flexibilising component is a liquid plasticizer.

42 . The method as claimed in claim 41 wherein said plasticizer is N-butylbenzenesulphonamide (BBSA).

43 . The method as claimed in claim 29 wherein said barrier layer comprises a barrier polymer layer.

44 . A method for providing a multi-layer flexible pipe for conveying a target fluid comprising the steps of:

providing at least one barrier polymer layer of polyamide-12 (PA-12) for providing internal fluid integrity.

45 . The method as claimed in claim 44 further comprising the steps of forming a variety of polyamide-12 material via a two stage process, the second stage of the two stage process including a step of introducing a salt of a weak acid in order to nullify acid formed during the first phase.

46 . A method as claimed in claim 45 wherein said PA-12 layer comprises a layer of a PA-12 variety.

47 . (canceled)

48 . (canceled)