API Connector Coating Thickness Control via Extrusion Passages
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Solution Overview
Problem
API threaded connectors often fail to provide reliable gas-tight sealing due to excessive coating thickness leading to deformation and excessive torque, which negatively impacts their performance in oilfield applications.
Innovation Solution
A connector assembly with a softer coating layer between threaded surfaces, featuring passages or cutting edges to remove excess coating material during screwing, ensuring accurate thickness adjustment and gas-tight sealing by extruding excess material or cutting it away, respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a soft metal plating is applied to the threaded surfaces to improve gas sealability, then gas-tight sealing is improved, but the coating thickness becomes excessive causing deformation and excessive make-up torque
Solution Approach 1:
The invention changes the material parameter by using a softer coating material that can be plastically deformed during make-up. This allows the coating to be extruded into passages, automatically adjusting the effective coating thickness to an optimal value that provides gas-tight sealing without excessive torque or deformation.
Solution Approach 2:
The invention extracts the excess coating material from the threaded engagement zone by providing passages that allow the softer coating to be extruded outward during make-up. This removes the harmful effect of excessive coating thickness while retaining the beneficial gas-tight sealing properties.
2Reliability
If a soft metal plating is applied to the threaded surfaces to improve gas sealability, then gas-tight sealing is improved, but unallowable deformation of the pin member and box member occurs
Solution Approach 1:
The invention extracts the excess coating material from the threaded engagement zone by providing passages that allow the softer coating to be extruded outward during make-up. This removes the harmful effect of excessive coating thickness while retaining the beneficial gas-tight sealing properties.
Solution Approach 2:
The invention changes the material parameter by using a softer coating material that can be plastically deformed during make-up. This allows the coating to be extruded into passages, automatically adjusting the effective coating thickness to an optimal value that provides gas-tight sealing without excessive torque or deformation.
3Reliability
If a soft metal plating is applied to the threaded surfaces to improve gas sealability, then gas-tight sealing is improved, but poor thread engagement occurs
Solution Approach 1:
The invention extracts the excess coating material from the threaded engagement zone by providing passages that allow the softer coating to be extruded outward during make-up. This removes the harmful effect of excessive coating thickness while retaining the beneficial gas-tight sealing properties.
Solution Approach 2:
The invention changes the material parameter by using a softer coating material that can be plastically deformed during make-up. This allows the coating to be extruded into passages, automatically adjusting the effective coating thickness to an optimal value that provides gas-tight sealing without excessive torque or deformation.
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 achieves accurate coating thickness adjustment and gas-tight sealing without excessive torque or deformation, enhancing the reliability and cost-effectiveness of API connectors for gas-tight applications.
Implementation Method 1
the coating layer is susceptible of plastic deformation due to screwing of the pin member and the box member together, and wherein said means for removing excess coating material from the coating layer comprises at least one passage arranged to allow said excess coating material to be pressed into the passage as a result of said plastic deformation
Implementation Method 2
any undesired clearance between the engaged threaded surfaces is filled with coating material so that gas-tight sealing of the engaged threaded surfaces is achieved
Data Source
AI summary
The invention provides a connector assembly for interconnecting tubular elements. The connector assembly comprises at least one pin member, at least one box member, and for each box member a respective coating layer. Each pin member has a threaded outer surface and each box member has a threaded inner surface allowing the pin member and the box member to be screwed together. Herein the respective coating layer is positioned between the threaded surfaces of the pin member and the box member. Each coating layer is of a softer material than said threaded surfaces. The connector assembly further comprises means for removing excess coating material during make up of the pin member and the box member.