One-Piece Coupling Torque Stops Metal Seals
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Solution Overview
Problem
Current threaded connections for tubulars in oil and gas fields lack a cost-effective solution that provides high torque capacity, pressure resistance equivalent to pipe burst limits, and efficient sealing without additional parts, especially for high-pressure fluids.
Innovation Solution
A threaded one-piece coupling with two torque stops and axial and radial metal-to-metal seals, designed to sustain pressures equivalent to pipe burst limits, utilizing a central deflection relief groove and tapered edges to distribute torque and pressure evenly, and plated with alloys like copper and zinc to prevent corrosion and galling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional threaded connections are used, then manufacturing cost is reduced, but pressure resistance and sealing capability deteriorate
Solution Approach 1:
The patent merges multiple functions into a single integrated coupling body: torque stop features, axial metal-to-metal seals, radial metal-to-metal seals, and pressure containment are all incorporated into one piece. This eliminates the need for separate sealing elements or additional components, achieving burst-proof pressure resistance while maintaining cost-effectiveness through simplified manufacturing.
2Reliability
If additional sealing parts are added, then sealing capability improves, but device complexity increases
Solution Approach 1:
The coupling integrates axial and radial metal-to-metal seals directly into the coupling body structure. The axial seals are formed by mating pin faces, while radial seals are created through the interaction of the coupling's internal geometry with the tubulars. This eliminates the need for separate sealing elements or additional components, achieving reliable sealing while maintaining simplicity.
Solution Approach 2:
The metal-to-metal seals are self-forming through the mechanical interaction of the coupling components during assembly. The axial seals are created by the mating pin faces pressing together under torque, and the radial seals are formed by the coupling's internal geometry constraining the tubulars. No additional sealing parts or assembly steps are required.
3Strength
If torque capacity is increased, then connection strength improves, but risk of deformation increases
Solution Approach 1:
The coupling incorporates predefined torque stop features (such as shoulders or ledges) that engage with corresponding features on the tubulars during assembly. These features limit the maximum torque applied to the connection, preventing over-torquing and deformation while ensuring sufficient torque capacity for secure connection. The torque stops are built into the coupling geometry before assembly.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a cost-effective, high-torque capacity connection that reduces leaks by up to 10% and allows for versatile torque control, maintaining seal pressures equivalent to or greater than tubular burst pressures, while being efficient in material use and manufacturing costs.
Implementation Method 1
plated with alloys like copper and zinc to prevent corrosion and galling
Implementation Method 2
plated with alloys like copper and zinc to prevent corrosion and galling
Implementation Method 3
two radial metal to metal seals, and an axial metal to metal seal between pin faces
Implementation Method 4
designed to sustain pressures equivalent to pipe burst limits
Implementation Method 5
utilizing a central deflection relief groove and tapered edges to distribute torque and pressure evenly
Implementation Method 6
utilizing a central deflection relief groove and tapered edges to distribute torque and pressure evenly
Data Source
AI summary
An improved threaded connection for joining tubulars for oil and gas field operations forms connected tubular strings. The improved threaded connection includes a one piece coupling comprising a body with an outer surface an inner surface and a central axis, a first tapered edge, a second tapered edge, first and second bearing faces for supporting load, weight, or both of the connected tubulars, a plurality of torque stops, and radial metal to metal seal surfaces. As the inner surface of the body is swaged onto each tubular, the inner surface of the body deflects away from the central axis, providing a plurality of bands of high contact pressure at each metal to metal seal between the inner surface of the body and each connected tubular to sustain seal pressures at the threaded one piece coupling.