Non-Circular Closure Elements for Reciprocating Pump Fluid Ends
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Solution Overview
Problem
High-pressure reciprocating pumps face issues with leakage and wear due to traditional circular sealing and retaining methods, which are prone to fatigue and invasive repairs, especially in high-stress areas like threaded connections.
Innovation Solution
The use of non-circular cross-sectional shapes for closure elements and fluid end segments allows for self-retention without threading, enabling easier installation, reducing wear, and facilitating corner seals that can be repaired or replaced without invasive procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional threaded retaining elements are used to secure closure elements, then the closure can be retained in the fluid end, but the threads are subject to high cyclical stress and prone to fatigue failure
Solution Approach 1:
The patent removes the threaded retaining element from the system entirely. The closure element is retained in the fluid end through friction fit and geometric interference of the non-circular cross-sections, eliminating the threads and their associated fatigue failure risks. This extraction of the problematic threaded connection resolves the contradiction between reliability and strength.
Solution Approach 2:
The closure element performs its own retention function through its non-circular cross-sectional geometry that mates with a corresponding non-circular bore in the fluid end. The shape compatibility creates automatic retention without requiring separate retaining elements or threaded connections, making the system self-sufficient and eliminating weak points.
2Ease of operation
If circular closure elements with threaded retaining elements are used, then the closure can be secured in the fluid end, but the installation and maintenance require invasive procedures and cause downtime
Solution Approach 1:
The patent divides the closure system into a modular non-circular closure element that can be independently installed and removed from the fluid end. This segmentation allows for quick replacement without affecting other components, reducing maintenance downtime and simplifying operations.
Solution Approach 2:
The non-circular cross-sectional shapes create an asymmetric fit between the closure element and the fluid end bore. This asymmetric geometry provides inherent retention while allowing for tool-free installation and removal, eliminating the need for threaded fasteners and reducing maintenance time while improving ease of operation.
3Reliability
If traditional radial seals are used on circular closure elements, then sealing can be provided, but the seals are prone to wear and difficult to repair
Solution Approach 1:
The patent employs non-circular cross-sectional shapes for both the closure element and the fluid end bore, creating an asymmetric sealing interface. This asymmetric geometry provides superior sealing through shape compatibility while allowing for easier inspection and replacement of sealing surfaces, as the non-circular shape makes wear patterns more visible and accessible.
Solution Approach 2:
Instead of using a radial seal that contacts the closure element peripherally, the patent inverts the sealing approach by having the sealing surfaces on the faces of the non-circular closure element. This face sealing approach is more durable and easier to repair than traditional radial seals, as the sealing surfaces can be readily accessed and replaced without removing the entire closure element.
Data Source
AI summary
A method of closing an externally open segment of a fluid end of a reciprocating pump with a closure assembly includes inserting a non-circular closure element into a segment of a fluid end casing in a first direction while the non-circular closure element is disposed in a first orientation. The non-circular closure element is rotated to a second orientation that is angularly offset from the first orientation with respect to at least one axis of rotation. The non-circular closure element is further moved within the segment of the fluid end casing in a second direction that is opposite the first direction to cause the non-circular closure element to seat within the segment.