Swaged Bumper Spring Assembly for Secure Mandrel End Retention
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Solution Overview
Problem
Conventional bumper spring assemblies in oil and gas wells are prone to damage from high-velocity plungers, leading to loosening of components and obstruction of fluid flow, resulting in reduced production and potential well shutdowns.
Innovation Solution
A robust bumper spring assembly design featuring a one-piece mandrel with a solid head piece and a concentric coil spring, secured without pins or set screws using a swaging process, and incorporating flow reliefs and ports to enhance durability and fluid flow efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bumper spring assemblies use pins or set screws to secure end pieces to the mandrel, then the assembly can be manufactured with simpler processes, but the components are prone to loosening under high-velocity plunger impact
Solution Approach 1:
The patent merges the end piece and mandrel into a single integrated component formed by swaging the mandrel onto the end piece. This eliminates the need for separate fastening elements like pins or set screws, resolving the contradiction by providing both secure component attachment (improving reliability) and maintaining manufacturing simplicity (preserving ease of manufacture) through a single swaging operation.
Solution Approach 2:
The patent replaces the mechanical fastening system (pins, set screws, threads) with a deformation-based mechanical bond created by swaging. The swaging process plastically deforms the mandrel to permanently secure the end piece, eliminating the need for reversible mechanical fasteners while maintaining manufacturing efficiency and improving reliability under impact loads.
2Strength
If bumper spring assemblies include traditional pinned components, then the structure can be assembled with standard fastening methods, but the pins are frequently sheared by high-velocity plungers causing component loosening
Solution Approach 1:
The patent combines multiple components (mandrel, end piece, and fastening mechanism) into a single integrated structure through swaging. This reduces the number of separate parts while increasing the strength of the connection, as the swaged bond creates a permanent mechanical attachment that cannot be sheared like traditional pins.
Solution Approach 2:
The patent extracts and eliminates the vulnerable pin components from the assembly by replacing them with an integrated swaged connection. This removes the weak link in the system that was prone to shearing under high-velocity plunger impact, thereby improving overall structural strength.
3Productivity
If conventional bumper springs use threaded end pieces secured with pins, then assembly is straightforward, but the pinned components can loosen and obstruct fluid flow
Solution Approach 1:
The patent integrates the end piece and mandrel into a single unit through swaging, eliminating the loose pinned components that could obstruct fluid flow. This merged structure maintains component stability (improving reliability) while preventing interference with fluid flow paths (improving productivity).
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 design significantly reduces the risk of component loosening and improves fluid flow by up to 20%, enhancing the longevity and performance of the bumper spring assembly.
Implementation Method 1
a distal portion of the tail end of the mandrel is expanded outward in a cold forming process against the threads in the cage nut next to the outward chamfer to lock the threads of the cage nut to the tail end of the mandrel
Data Source
AI summary
A bumper spring assembly having a one piece mandrel including an integral head piece is further configured with a cage assembly retained on the mandrel with a cage nut locked to the mandrel to obviate the need for pins, set screws, and the like, to provide a more robust assembly. In two embodiments the cage nut is locked to the mandrel in a swaging operation. Improved flow of fluids through and around the bumper spring assembly are also provided.