Selective Swivel Joint Coating for Erosion-Prone Outlet Surfaces
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Solution Overview
Problem
Conventional swivel joints used in high-pressure oil and gas applications, such as fracking, experience rapid wear and failure due to erosion, abrasion, and corrosion from caustic fluids and particulates, leading to premature failure at critical surfaces.
Innovation Solution
A swivel joint design featuring selectively coated surfaces, particularly on the outlet face and transition sections, with a metal alloy coating like tungsten carbide, applied using thermal spray techniques, to reduce wear and prevent corrosion, while excluding the coating from critical areas like the main bore and bearing race sections to avoid delamination and unwanted wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional swivel joints are used in high-pressure oil and gas applications, then they can transfer fluids at high pressure, but the interior surfaces wear and fail extremely quickly due to erosion, abrasion, and corrosion
Solution Approach 1:
The patent applies a hard coating material (such as tungsten carbide, stellite, or ceramic) selectively to specific interior surfaces of the swivel joint that are most susceptible to wear, including the outlet face, transition section, and outlet section. This local quality enhancement provides erosion and corrosion resistance where needed most while leaving other areas unchanged.
Solution Approach 2:
The patent combines a base metal material (such as stainless steel or alloy steel) with a hard coating material (such as tungsten carbide, stellite, or ceramic) to create a composite structure. The base material provides structural integrity while the coating material provides resistance to erosion, abrasion, and corrosion from caustic fluids and particulates.
2Object-affected harmful factors
If a hard coating is applied to all interior surfaces to prevent wear, then corrosion and erosion resistance improves, but the coating may delaminate from bearing race sections and cause unwanted wear
Solution Approach 1:
The patent selectively applies the hard coating material only to specific interior surfaces (outlet face, transition section, outlet section) that are most susceptible to erosion and corrosion from fluid flow, while deliberately excluding bearing race sections and other areas where the coating would cause harm. This localized approach enhances protection where needed while avoiding delamination and unwanted wear at bearing interfaces.
Solution Approach 2:
The patent divides the interior surfaces of the swivel joint into distinct zones: coated areas (outlet face, transition section, outlet section) and uncoated areas (bearing race sections, main bore). This segmentation allows different surface treatments in different locations to optimize both wear resistance and bearing performance.
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 selective coating significantly extends the swivel joint's lifespan by reducing erosion and corrosion, preventing premature failure and maintaining the integrity of the bearing races, thus reducing maintenance and downtime in high-pressure fluid systems.
Implementation Method 1
applied using thermal spray techniques
Data Source
AI summary
A swivel joint includes a first pipe section and a second pipe section. The pipe sections may define a flow path via which fluid passes through the swivel joint. One or more surfaces proximate a junction of the first pipe section and the second pipe section may be selectively coated to resist wear from erosion, corrosion, and or abrasion.