Flow Cage Assembly With Interference Fit to Prevent Downhole Pump Leaks
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Solution Overview
Problem
Conventional flow cage assemblies in reciprocating downhole pumps face durability issues due to wear and leakage, particularly at the sealing member and threaded connections, which can lead to fluid leaks and structural weaknesses.
Innovation Solution
A method and kit for assembling a flow cage assembly involving a body with an expandable axial chamber, a tubular insert, and a retaining element forming an interference fit, which eliminates the need for a sealing member and enhances structural integrity by using a tubular insert with ribs and a retaining element with an annular portion and plug portion to securely retain the insert within the body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a sealing member is used to prevent leaks at the threaded connection between the flow cage assembly and the top bushing, then leakage protection is improved, but the sealing member becomes a potential failure point due to wear from repeated ball movement
Solution Approach 1:
The patent removes the sealing member from the assembly by transitioning from a threaded connection to a friction weld connection between the top bushing and the flow cage body. This extraction eliminates the sealing member and its associated leakage risks while maintaining connection integrity through the friction weld joint.
2Ease of manufacture
If a threaded connection is used to connect the flow cage assembly to the top bushing, then ease of assembly is improved, but the threaded connection creates weak points vulnerable to cracking and fatigue
Solution Approach 1:
The patent merges the connection function into a single integrated friction weld joint between the top bushing and flow cage body, eliminating the separate threaded connection. This merging creates a stronger, more unified structure that eliminates weak points while maintaining assembly capability through the friction welding process.
3Ease of manufacture
If a screw-in ball seat bushing is used to retain the insert, then ease of assembly is improved, but fluid leaks between threads cause erosive wear and loosening of the connection
Solution Approach 1:
The patent removes the screw-in ball seat bushing and its threaded connection, replacing it with a friction weld-retained insert assembly. This extraction eliminates the thread interface that allows fluid leakage and subsequent erosive wear, while maintaining insert retention through the friction weld connection.
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 improved durability and reduced risk of leaks, enhancing the structural integrity and operational efficiency of the flow cage assembly by eliminating potential failure points and ensuring secure retention of the insert within the body.
Implementation Method 1
providing a body having an axial chamber and a plurality of side ports extending through the body into the axial chamber, wherein the axial chamber has a first diameter and is expandable to a second diameter when the body is heated
Implementation Method 2
cooling the body such that the body and the retaining element form an interference fit
Data Source
AI summary
Methods and kits for assembling a flow cage assembly are provided. The flow cage assembly may be used in a traveling valve, a standing valve, or a top plunger adapter of a downhole reciprocating pump. In some embodiments, the method comprises assembling a body, a tubular insert, and a retaining element such that the retaining element forms an interference fit with the body and thereby securely retains the tubular insert within the body. Top plunger adapters are also provided, assembled from embodiments of the methods and kits.