Flexible pipe

• US 4,383,554 A
• Filed: 07/14/1981
• Issued: 05/17/1983
• Est. Priority Date: 07/31/1980
• Status: Expired due to Fees

• Current Assignee: Mobil Oil Corporation (Exxon Mobil Corporation)
• Original Assignee: Mobil Oil Corporation (Exxon Mobil Corporation)
• Inventors: Merriman, Horace B.
• Primary Examiner(s): Marcus, Stephen
• Assistant Examiner(s): Thronson, Mark
• Application Number:
  US06/282,994
• Time in Patent Office: 672 Days
• Field of Search: 138/100, 138/101, 138/102, 138/109, 138/108, 138/138, 138/139, 138/174, 138/127, 138/120, 138/147, 138/155
• US Class Current: 138/101
• CPC Class Codes: E21B 17/015 Non-vertical risers, e.g. articulated or catenary-type
• CPC Class Codes: F16L 11/08 with reinforcements embedded in the wall F16L11/11 takes precedence
• CPC Class Codes: F16L 11/18 Articulated hoses, e.g. composed of a series of rings

Abstract

A flexible pipe comprising a first set of stress bearing elements extending substantially the whole length of the pipe, for accommodating maximum hoop stress resulting from flow of pressurized fluid through the pipe, and a second set of stress bearing elements extending substantially the whole length of the pipe for accommodating longitudinal stress resulting from a flow of pressurized fluid through the pipe.

Claims

1. A flexible pipe comprising first means including a first set of stress bearing elements extending substantially the whole length of the pipe, for accommodating maximum hoop stress resulting from flow of pressurized fluid through the pipe, and second means including a second set of stress bearing elements in the form of a series of keepers circumferentially staggered around said first set of elements which are arranged to hold said first set of elements in place and limit relative movement thereof extending substantially the whole length of the pipe for accommodating longitudinal stress resulting from a flow of pressurized fluid through the pipe.

2. The pipe of claim 1 wherein said keepers are in the form of narrow resilient bars.

3. A flexible pipe comprising a plurality of loosely interengaged rings which allow limited relative axial and radial movement, thus permitting the pipe to flex both radially and longitudinally, the rings being held in place by a plurality of keepers arranged externally of the rings and extending longitudinally of the pipe, the keepers being arranged both to hold the rings in place and to limit the relative movement of the rings, the pipe also including an outer fluid type covering and at least one inner fluid type liner, the rings being so constructed and arranged and being of such thickness and tensile strength as to withstand the maximum hoop stress developed internally in the pipe when high pressure fluid is flowing through it, and the keepers being of sufficient high tensile strength to withstand the endwise or longitudinal stresses developed in the pipe when fluid is flowing through it, the rings carrying substantially the whole of the hoop stress and the keepers carrying substantially the whole of the longitudinal stress.

4. A flexible pipe comprising a plurality of rings which are loosely inter-engaged so as to allow limited relative axial and radial movement, thus permitting the pipe to flex both radially and longitudinally, the rings being held in place by a plurality of keepers which extend longitudinally of the pipe and are arranged both to hold the rings in place and to limit the relative movement of the rings, the pipe also including an outer fluid tight covering and at least one inner fluid tight liner, the inter-engaging rings being of such thickness and tensile strength as to withstand the hoop stress developed internally in the pipe when high pressure fluid is flowing through it, and the keepers being of sufficiently high tensile strength to withstand the endwise or longitudinal stresses developed in the pipe by fluid flowing through it.

5. The pipe of claim 4 wherein said keepers are arranged as a series of segmental bars extending longitudinally of the pipe, each bar engaging and holding a pair of adjacent rings.

6. The pipe of claim 5 wherein said bars or keepers are staggered so that adjacent bars do not engage the same pair of rings, the staggering being circumferentially around the pipe.

7. The pipe of claim 6 wherein one keeper bar engages one pair of rings and the next circumferentially adjacent bar engages one of that pair of rings and the next axially adjacent ring.

8. The pipe according to any of claims 6 or 7 wherein said keepers are sufficiently resilient to enable them to be strung onto the rings.

9. The pipe of claim 5 further comprising means for permitting interengagement between the keeper bars and the rings, wherein said means comprises wedging surfaces at the end of each bar and corresponding wedging surfaces projecting outwardly radially from the rings so that axial movement of the rings tightens their engagement with the keeper bars.

10. The pipe of claim 4 further comprising a steel helically wound core for providing support for said at least one inner fluid tight liners.

11. The pipe of claim 4 wherein said outer covering is of extruded elastomeric material.

12. The pipe of claim 5 wherein the keeper bars are loosely held in place by steel bands engaging grooves in the bars and extending circumferentially around the pipe.

13. The pipe of claim 4 further comprising an inner cable, wire or plurality of wires extending axially along the central space within the pipe and supported therein by a plurality of spiders for containing end wire stresses.

14. The pipe of claim 13 further comprising means for adjusting the tension on the inner cable or wire.

15. The pipe of claim 4 further comprising a flanged joint at each end of the pipe for enabling the pipe to be connected to an adjacent length of pipe or to an oil or gas well terminal or to a receiving buoy or ship.

16. The pipe of claim 15 wherein the end flanged joint is attached to the pipe by means including a pair of sealed end rings for engaging a resilient metal ring, and wherein a metal plug, when tightened into the end flanged joint, causes the end rings to press inwardly upon the resilient metal ring and engage the inner liners so as to seal them.

17. The pipe of claim 16 wherein the screwed-in plug in the end flanged joint (fitting) also forms the first of the metal rings which are held in place by the keepers.

18. The flexible pipe of claim 4 installed in an under-sea oil well installation so as to connect an under-sea oil terminal to a buoy or ship or other oil receiving point on the surface of the sea.