Frustroconical Ceramic Plug Head Retention
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Solution Overview
Problem
Ceramic plug head assemblies in extreme operating environments, such as high temperatures and pressures, face issues like component weakening and separation due to differential thermal expansion and exposure to corrosive or abrasive fluids, leading to potential fractures and loss of integrity.
Innovation Solution
A plug head assembly design featuring a ceramic plug head with a frustroconical geometry, a sleeve with a higher coefficient of thermal expansion than the plug head, and a retainer system that applies radial compressive stress to maintain retention and protect against thermal shocks, using materials like sintered silicon carbide and fluoropolymers to enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional retainer apparatus is used to retain a ceramic plug head, then the assembly can be manufactured with standard components, but the retainer apparatus expands at a higher rate than the ceramic plug head at elevated temperatures, making the fit loose and compromising retention
Solution Approach 1:
The patent changes the geometric parameters of the retainer apparatus by introducing a frustroconical shape with specific taper angles. This geometric modification allows the retainer to maintain proper fit and retention on the ceramic plug head across a range of temperatures, compensating for differential thermal expansion through the tapered geometry rather than requiring complex adjustable mechanisms.
Solution Approach 2:
The retainer apparatus employs asymmetric frustroconical geometry with specific taper angles rather than symmetric cylindrical shapes. This asymmetric design creates a mechanical interference fit that maintains retention integrity despite thermal expansion differences, as the tapered geometry prevents uniform loosening that would occur with symmetric designs.
2Temperature
If ceramic plug heads are used in extreme operating environments, then the plug head can withstand high temperatures and pressures, but thermal events and crushing lodged solids cause fractures that separate the ceramic plug head from the assembly or compromise integrity
Solution Approach 1:
The retainer apparatus is designed to apply pre-compressive force to the ceramic plug head before thermal or mechanical events occur. This pre-compression cushioning helps prevent fracture by counteracting tensile stresses that develop during thermal expansion and mechanical loading, thereby maintaining integrity in extreme environments.
Solution Approach 2:
The patent creates a composite assembly combining the ceramic plug head with the retainer apparatus made of different materials having complementary properties. The retainer material is selected to provide both thermal stability and mechanical strength, creating a composite structure that leverages the advantages of each material to withstand extreme temperatures and pressures while preventing fracture.
3Reliability
If the retainer apparatus is tightly fitted to the ceramic plug head, then retention is maintained, but the differential thermal expansion causes stress concentration that may lead to fractures
Solution Approach 1:
The frustroconical geometry with optimized taper angles distributes the contact stress along a larger surface area rather than concentrating it at a single interface. This parameter optimization allows the retainer to maintain tight fit and retention while reducing peak stress concentrations that would otherwise lead to ceramic fracture during thermal cycling.
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
The design significantly enhances the resistance of plug head assemblies to thermal and mechanical stresses, reducing the likelihood of fractures and maintaining assembly integrity under extreme conditions, while also improving flow control performance and reducing shear stresses on the ceramic components.
Implementation Method 1
heating a thick band to an assembly temperature, disposing the thick band about a circumference of a monolithic flat SiC plug head, and bringing the thick band and flat SiC plug head to a room temperature
Implementation Method 2
the thick band exerts a radial stress upon the flat SiC plug head at a room temperature and at an operating temperature... protecting against thermal shocks
Data Source
AI summary
In accordance with various embodiments, a plug head assembly is provided comprising a ceramic plug head having a frustroconical geometry, wherein the ceramic plug head has a proximal terminus and a distal terminus, wherein the ceramic plug head has a first coefficient of thermal expansion (CTE), a sleeve having a frustroconical geometry conforming to the ceramic plug head and a second CTE, wherein the second CTE is greater than the first CTE, a distal retainer having a frustroconical geometry conforming to the sleeve, the distal retainer having a first engagement portion for engaging the a proximal retainer, the proximal retainer having a second engagement portion for engaging the distal retainer, and a base that couples with the proximal retainer. In addition, thick banded plug heads are provided.