Clamped Fluid End Retention for Seal Wear and Thread Cracking
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Solution Overview
Problem
Existing fluid end assemblies in high-pressure reciprocating pumps face issues with seal wear and erosion, leading to frequent maintenance and reduced lifespan due to the use of multiple packing seals and internal threads that are prone to cracking under cyclic pressure changes.
Innovation Solution
A fluid end assembly design featuring a single multi-contact V-nested spring seal with an integrated wear ring and a clamp system that secures the retainer to the housing without internal threads, utilizing an energizing component to maintain sealing without additional compression and minimizing wear on the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple packing seals are used in the fluid end assembly, then sealing reliability is improved, but seal wear increases and maintenance frequency increases
Solution Approach 1:
The patent combines multiple sealing functions into a single multi-contact V-nested spring seal assembly. This integrated design maintains reliable sealing through multiple contact points while reducing the number of separate seal components, thereby decreasing overall wear and maintenance requirements compared to using multiple separate packing seals.
Solution Approach 2:
The V-nested spring seal employs a nested structure where spring elements are arranged concentrically around the plunger. This nested configuration allows multiple sealing contacts to be achieved within a single integrated assembly, providing reliable sealing while minimizing the number of discrete seal components that would otherwise require individual replacement.
2Ease of operation
If internal threads are used to secure the retainer, then ease of assembly is improved, but cracking under cyclic pressure changes occurs
Solution Approach 1:
The patent removes internal threads from the housing structure by using an external clamp mechanism to secure the retainer. This extraction of the threading function eliminates the stress concentration points and crack initiation sites that would otherwise exist in threaded holes subjected to cyclic pressure changes, while still providing secure retention.
Solution Approach 2:
The patent introduces a clamp as an intermediary component between the retainer and the housing. This external clamp serves as a mediator that provides the necessary securing function without requiring internal threads in the housing, thereby preventing cracking while maintaining ease of assembly through a simple clamping mechanism.
3Reliability
If additional compression is applied to maintain sealing, then sealing effectiveness is improved, but wear on the housing increases
Solution Approach 1:
The V-nested spring seal incorporates an energizing component that automatically maintains sealing pressure through its spring force. This self-service mechanism continuously applies the necessary compression to maintain sealing effectiveness without requiring external adjustment or additional compressive force from the housing structure, thereby minimizing wear on the housing.
Solution Approach 2:
The patent changes the sealing mechanism from relying on static compression from the housing to utilizing dynamic spring force from the energizing component. This parameter change allows the seal to maintain effectiveness through elastic deformation of the spring rather than continuous mechanical compression, significantly reducing wear on the housing surfaces.
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
Enhances the performance and longevity of the fluid end assembly by reducing seal wear, eliminating the need for frequent maintenance, and preventing cracking of internal threads, thus improving operational efficiency and extending the life of the components.
Implementation Method 1
The seal comprises an energizing component configured to expand radially when compressed longitudinally
Implementation Method 2
The clamp comprises an inner clamp surrounded by an outer clamp
Data Source
AI summary
A fluid end assembly comprising a plurality of fluid end sections positioned in a side-by-side relationship. Each section comprises a housing containing a reciprocating plunger. One and only one packing seal is installed within the housing and surrounds and engages an outer surface of the plunger. A retainer compresses and holds the packing seal within the housing. The retainer is secured to the housing using a clamp, such that no threads are formed in the housing of the fluid end section and no threads are formed in the retainer.