Non-Circular Closure Element for Reciprocating Pump Fluid End
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Solution Overview
Problem
High-pressure reciprocating pumps face issues with leakage and wear due to traditional circular sealing mechanisms, which are prone to fatigue and invasive repairs, and require threaded connections that are susceptible to cyclical stress.
Innovation Solution
A non-circular closure element with a seating and closure section, allowing self-retention within a fluid end bore without threading, and a retaining assembly that secures the closure element to prevent removal by pressure or suction, enabling easier installation and reducing wear on sealing areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional circular closure elements with threaded connections are used, then the closure element can be secured in the fluid end, but the threaded connections are subject to high cyclical stress and prone to fatigue failure
Solution Approach 1:
The closure element transitions from a circular cross-section to a non-circular cross-section (such as triangular, square, or rectangular). This asymmetric shape eliminates the need for threaded connections, as the non-circular geometry provides inherent mechanical engagement with the bore through shape complementarity rather than threaded fastening, thereby removing the stress concentration points and fatigue failure modes associated with threads
Solution Approach 2:
The threaded connection component is completely removed from the system. Instead of using separate threads on both the closure element and the bore, the invention extracts the fastening function and integrates it directly into the non-circular geometry of the closure element itself, which naturally resists rotation and axial movement through its shape
2Strength
If threaded retaining elements are used to secure the closure element, then the closure can be retained, but the threads experience fatigue failure under high cyclical stress
Solution Approach 1:
The non-circular cross-sectional shape (triangular, square, or rectangular) creates asymmetric geometric interlocking between the closure element and the bore. This asymmetric engagement provides retention strength through shape complementarity and mechanical interference, eliminating the need for threaded fasteners that are susceptible to fatigue under cyclical loading conditions
Solution Approach 2:
The functions of sealing, retention, and positioning are merged into the non-circular geometry of the closure element itself. The same geometric features that provide the seal also provide the retention mechanism, eliminating the need for separate threaded retaining elements and their associated fatigue problems
3Reliability
If circular closure elements are used, then traditional sealing techniques can be applied, but the sealing location is fixed and creates wear points
Solution Approach 1:
The non-circular cross-section (triangular, square, or rectangular) allows the sealing surface to be positioned at different locations along the closure element's perimeter. This asymmetric geometry enables the seal to be placed optimally—either inward adjacent to the pumping chamber to protect interior edges or outward adjacent to the exterior surface for easier access and repair
Solution Approach 2:
The invention moves the sealing function from a fixed radial position to a flexible position along the longitudinal axis of the closure element. The non-circular geometry allows the seal to be located at different axial positions, creating new degrees of freedom in seal placement that were not available with traditional circular designs
Data Source
AI summary
A closure element for a fluid end of a reciprocating pump is installable within a segment of a casing of the fluid end to substantially close the segment. The closure element includes a main body that extends from an interior surface to an exterior surface, and at least a portion of the main body has a non-circular cross-sectional shape. A fluid end for the closure element may include a plurality of segments and at least a portion of at least one segment of the plurality of segments may have a non-circular cross-sectional shape configured to receive and secure a closure element with a non-circular cross-sectional shape.