Composite pipeline sleeper with hollow outer shell and rigid internal reinforcement
A composite pipeline sleeper features a rotationally molded outer shell, and an internal reinforcement structure that is disposed within, is materially distinct from, and is more rigid than, said rotationally molded outer shell. A topside of said pipeline sleeper comprises a cradle-shaped area for seated receipt of a pipe there atop.
1. A composite pipeline sleeper comprising:
a rotationally molded outer shell having a hollow interior space;
an internal reinforcement structure that is disposed within said hollow interior space, and that is materially distinct from, and more rigid than, said rotationally molded outer shell;
wherein a topside of said pipeline sleeper comprises a cradle-shaped area for seated receipt of a pipe there atop, the hollow interior space of the rotationally molded outer shell exceeds the internal reinforcement structure in volume, and the hollow interior space includes unoccupied air space between the internal reinforcement structure and the rotationally molded outer shell at areas thereof other than said cradle-shaped area.
2. The composite pipeline sleeper of claim 1 wherein the internal reinforcement structure comprises a metal construction.
3. The composite pipeline sleeper of claim 2 wherein the internal reinforcement consists only of said metal construction.
4. The composite pipeline sleeper of claim 1 wherein the internal reinforcement structure comprises a lower base seated atop an interior floor area of the rotationally molded outer shell, and said areas at which there exits said unoccupied air space between the internal reinforcement structure and the rotationally molded outer shell exclude both said cradle shaped area and said interior floor area.
5. The pipeline sleeper of claim 1 wherein the cradle-shaped area is defined by a topside area of the rotationally molded outer shell, which is underlaid by a conformingly shaped section of the internal reinforcement.
6. The pipeline sleeper of claim 5 wherein the conformingly shaped section of the internal reinforcement comprises a cradle-shaped member having a concave topside overlaid by the topside area of the rotationally molded outer shell.
7. The pipeline sleeper of claim 1 comprising threaded inserts by which the internal reinforcement structure was supportable in a rotational mold during production the pipeline sleeper.
8. The pipeline sleeper of claim 1 wherein the internal reinforcement structure comprises at least one mold-through hole therein at which the internal reinforcement structure is engaged by molded material of the rotationally molded outer shell.
9. The pipeline sleeper of claim 1 wherein the rotationally molded outer shell comprises upwardly protruding features at a topside thereof, and compatibly-shaped cavities at an underside of the rotationally molded outer shell at aligned positions below the upwardly projecting features to enable receipt of the upwardly projecting features in the compatibly-shaped cavities of a matching second pipeline sleeper stacked atop the pipeline sleeper.
10. The pipeline sleeper of claim 1 comprising one or more through-bores passing through the outer shell to enable lifting of the pipeline sleeper by engagement of lifting aids through said through-bores.
11. The pipeline sleeper of claim 10 wherein each through-bore penetrates only the rotationally molded outer shell, and not the internal reinforcement structure.
12. The pipeline sleeper of claim 10 wherein each through-bore is delimited by a respective through-tunnel of the rotationally molded outer shell.
13. A composite pipeline sleeper comprising:
a rotationally molded outer shell;
an internal reinforcement structure that is disposed within, is materially distinct from, and is more rigid than, said rotationally molded outer shell;
wherein:
a topside of said pipeline sleeper comprises a cradle-shaped area for seated receipt of a pipe there atop; and
the internal reinforcement structure comprises a plurality of upright plates, at least some of which lie in cross-wise relation to one another.
14. The pipeline sleeper of claim 13 wherein said plurality of upright plates comprises at least one longitudinal plate lying in which cradle-shaped area is concavely curved, and a plurality of stiffening plates lying cross-wise to said longitudinal plate.
15. A method of producing the composite pipeline sleeper of claim 1 , said method comprising rotationally molding said outer shell of said pipeline sleeper in surrounding relation to said internal reinforcement structure that is materially distinct from, and more rigid than, said outer shell.
16. The method of claim 15 comprising, before rotationally molding said outer shell, removably fastening the internal reinforcement structure to a rotational mold in a position maintaining gap spaces between walls of the mold and surfaces of the internal reinforcement structure to accommodate flow of molten material into said gap spaces during the rotational molding to create walls of the outer shell around said internal reinforcement structure.
17. The method of claim 16 wherein said fastening comprises engaging a first threaded insert fastener with a threaded mold fastener, lowering a hole in the internal reinforcement structure over the threaded insert fastener, and securing said internal reinforcement structure to threaded insert fastener.
18. The method of claim 17 wherein said first threaded insert fastener comprises a female insert fastener and the mold fastener comprises a male mold fastener.
19. The method of claim 18 comprising, before lowering the hole in the internal reinforcement structure over the female insert fastener, installing a spacer over said female insert fastener so that the internal reinforcement structure is seated on said spacer when lowered over the female insert fastener.
20. The method of claim 17 wherein securing said internal reinforcement structure to threaded insert fastener comprises engaging a second insert fastener to the first insert fastener.
21. A composite pipeline sleeper comprising:
a rotationally molded outer shell;
an internal reinforcement structure that is disposed within, is materially distinct from, and is more rigid than, said rotationally molded outer shell;
wherein:
a topside of said pipeline sleeper comprises a cradle-shaped area for seated receipt of a pipe there atop; and
the pipeline sleeper comprises threaded inserts by which the internal reinforcement structure was supportable in a rotational mold during production the pipeline sleeper.