Fluid End Cartridge Check Valves With Wedge Retention
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Solution Overview
Problem
Conventional fluid end assemblies in the Oil & Gas industry face issues with valve wear, maintenance accessibility, and fatigue cracking, leading to premature failure and high operational costs due to complex geometry and hammer nut designs.
Innovation Solution
A fluid end design featuring a stainless-steel sleeve arrangement with cartridge-style check valves and a wedge retention system for easy maintenance and stress control, replacing traditional hammer nut designs, and incorporating a machined surface to remove metallurgical defects, allowing for superior operational life and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hammer nut designs are used to seal the fluid end, then the sealing function is achieved, but the tightening variability and potential seal failure occur due to pulsating pressure effects
Solution Approach 1:
The patent replaces the conventional hammer nut mechanical tightening system with a welded seal system. The seal is applied to the fluid end bore and welded in place, eliminating the need for hammer nuts and their associated tightening variability issues. This substitution of mechanical fastening with welding resolves the contradiction by providing consistent, reliable sealing without the pulsating pressure effects that cause hammer nut failure.
2Reliability
If complex geometry is used to locate valve seats and components within the fluid end, then the valve function is achieved, but the manufacturing complexity and fatigue stress cracking increase
Solution Approach 1:
The patent segments the valve assembly from the fluid end body by using separate, removable valve assemblies that can be inserted and extracted without complex internal geometry. The fluid end bore is simplified to a basic cylindrical shape, while the valve assembly contains all the complex valve seat and component location features. This segmentation resolves the contradiction by maintaining valve functionality while eliminating complex fluid end geometry that causes manufacturing difficulties and fatigue cracking.
Solution Approach 2:
The patent extracts the complex valve location geometry from the fluid end body and places it in separate valve assemblies. The fluid end is reduced to a simple bore structure, while the valve assemblies contain all the complex features needed for valve seat location and component positioning. This extraction resolves the contradiction by maintaining valve function while simplifying the fluid end geometry to reduce manufacturing complexity and fatigue stress.
3Reliability
If check valves are designed as separate components requiring assembly within small bores, then the valve operation is achieved, but the maintenance accessibility and assembly difficulty increase
Solution Approach 1:
The patent merges multiple valve components (check valves, valve seats, springs, and related parts) into integrated valve assemblies that function as complete units. Each valve assembly is designed to be inserted as a single component into the fluid end bore, eliminating the need for complex assembly of small parts within confined spaces. This merging resolves the contradiction by maintaining valve operation while dramatically improving maintenance accessibility, as entire valve assemblies can be quickly removed and replaced without disassembling small components in tight bores.
4Strength
If AISI 4130 steel is used for fluid end monoblocks, then the initial strength is sufficient, but the fatigue stress cracking occurs prematurely under pumping operations
Solution Approach 1:
The patent changes the material parameter from AISI 4130 steel to a different material composition that provides superior fatigue resistance. The new material maintains sufficient initial strength while significantly extending the service life by resisting fatigue stress cracking under pumping operations. This parameter change in material selection resolves the contradiction by providing both the required initial strength and extended duration of action without premature failure.
Data Source
AI summary
Embodiments presented provide for a fluid end that has cartridge style check valves that may be serviced through a vertical bore.