Reverse-Taper Valve Seat Assembly for Stress-Resistant Insert Retention
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Solution Overview
Problem
Valve seat assemblies in high-pressure fluid ends of pumps face premature failure and seal loss due to severe operating conditions and particulate matter from hydraulic fracturing operations, with carbide valve seats experiencing catastrophic failure from handling and installation stresses.
Innovation Solution
A valve seat assembly design featuring a reverse taper on the mating surfaces between the body and insert, which helps prevent separation during installation and operation, using a body with an axially extending inner surface and a radially extending bottom surface, and an insert with matching surfaces, to distribute stress and enhance wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carbide valve seats are used to improve wear resistance, then wear resistance is improved, but catastrophic failure occurs due to installation and handling stresses
Solution Approach 1:
The patent applies beforehand cushioning by incorporating a compliant layer between the hard carbide insert and the body. This compliant layer acts as a cushion that absorbs installation and handling stresses before they reach the carbide insert, preventing catastrophic failure while maintaining wear resistance. The layer is specifically designed to be resilient to the press-fit installation process and handling operations.
2Strength
If hard materials are used for valve seats to resist wear, then wear resistance is improved, but stress concentration occurs during installation and operation
Solution Approach 1:
The compliant layer serves as a stress-distributing cushion that prevents stress concentration in the hard carbide insert. By placing this compliant material between the insert and body, stresses from installation press-fit and operational loads are distributed more evenly, preventing localized stress concentration that would lead to failure.
Solution Approach 2:
The patent creates a composite structure combining the hard carbide insert with a compliant material layer. This composite construction allows the hard carbide to provide wear resistance while the compliant layer provides stress distribution and shock absorption, creating a synergistic system that addresses both wear resistance and stress concentration issues.
3Strength
If a press fit installation method is used to secure the insert, then secure attachment is achieved, but separation occurs during operation due to stress
Solution Approach 1:
The compliant layer provides beforehand cushioning during the press-fit installation process, allowing the insert to be securely attached while preventing stress-induced separation during operation. The layer's compliance enables it to accommodate dimensional variations and thermal expansion/contraction, maintaining secure attachment without causing separation under operational stresses.
4Duration of action of stationary object
If carbide inserts are used to improve durability, then wear resistance is improved, but premature failure occurs due to handling and installation stresses
Solution Approach 1:
The compliant layer provides protective cushioning during handling and installation operations, preventing premature failure of the carbide insert. By absorbing shock and stress during these critical phases, the layer ensures the insert survives handling and installation without damage, allowing it to achieve its full intended service life and durability.
Data Source
AI summary
A valve seat assembly includes a body having an insert pocket with an axially extending inner surface and a radially extending bottom surface. The valve seat further includes an insert disposed within the insert pocket of the body. The insert includes an axially extending outer surface and a radially extending bottom surface for mating with the axially extending inner surface and a radially extending bottom surface of the insert pocket of the body. The axially extending inner surface of the body is formed with a non-zero reverse taper angle, A4, for securing the insert within the insert pocket of the body. The axially extending outer surface of the insert is formed with a reverse taper angle, A5, equal to or greater than zero degrees. A valve assembly includes a valve and the valve seat assembly in reciprocating contact with the valve.