Filament-Reinforced Tubular Threaded Coupling Without Fiber Cutting
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Solution Overview
Problem
Filament reinforced tubulars, particularly those produced by centrifugal or rotational casting, face challenges in creating screw threads without reducing material strength, and traditional connections like glued couplings are time-consuming and irreversible.
Innovation Solution
A filament-reinforced tubular design with a core member and fibre mats, secured by a thermoset cover, allows for screw threads with enhanced strength and compatibility with screw couplings, enabling efficient assembly and disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If screw thread is machined into the tubular surface, then screw thread is created, but the filaments are cut and material strength is reduced
Solution Approach 1:
The screw thread form is created preliminarily during the centrifugal casting process itself, before the tubular is fully formed. Fiber mats are arranged in the desired thread pattern and then the tubular is cast around them, so the thread form is built in rather than machined afterward, avoiding filament cutting
Solution Approach 2:
Instead of creating the screw thread by removing material (machining), the invention creates it by adding material in the desired form (building the thread pattern with fiber mats during casting). This inverts the traditional approach from subtractive to additive manufacturing of the thread form
2Strength
If multiple layers of fiber mats are wound around a die to build screw thread, then reinforced screw threads with continuous filaments are obtained, but the process cannot be used for centrifugal cast tubulars
Solution Approach 1:
The invention merges two previously separate processes: the centrifugal casting process and the fiber mat winding process. By integrating the thread-forming fiber mats directly into the centrifugal casting operation, the patent enables both continuous filaments and centrifugal cast quality to coexist in the same tubular
Solution Approach 2:
The centrifugal casting process is adapted to serve multiple functions: it simultaneously creates the tubular body and forms the screw thread structure using fiber mats. This makes the process universal enough to handle both the main tubular formation and the threaded feature creation in one operation
3Ease of manufacture
If glued couplings are used to connect tubulars, then connections are made, but the process is time-consuming and irreversible
Solution Approach 1:
The invention replaces the chemical bonding mechanism (glue) with a mechanical connection mechanism (screw threads). This substitution enables reversible, time-efficient connections while maintaining connection strength, as mechanical threading can be quickly assembled and disassembled compared to adhesive bonding
Data Source
AI summary
A riser section includes two filament-reinforced tubulars and a coupling sleeve for connecting the two filament-reinforced tubulars. The coupling sleeve includes a screw thread at opposite ends for cooperating with a screw thread provided on sections of the filament-reinforced tubulars. The riser section includes two torque locks, wherein the torque locks are each mounted on one of the filament-reinforced tubulars, and are on opposite ends of the coupling sleeve. The torque locks are provided with coupling teeth extending in an axial direction. The coupling sleeve is at opposite ends provided with coupling teeth extending in the axial direction. When the tubulars are screwed into the coupling sleeve and the torque locks have been mounted to secure the rotational movement of the tubulars relative to the coupling sleeve, the coupling teeth of each of the torque locks engages the coupling teeth of the coupling sleeve such that they block rotation of the torque lock relative to the coupling sleeve and allow for movement of the torque lock relative to the coupling sleeve in the axial direction, and thus allow for elongation of the sections of the tubulars including the screw thread. The pitch of the screw thread of the tubulars increases in a direction away from the end of the tubular, and the pitch of the screw threads of the coupling sleeve increases in a direction towards the end of the coupling sleeve.