Shutoff Valve Disc Assembly with Captured Spring-Energized PTFE Seal
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Solution Overview
Problem
Conventional disc assemblies for shutoff valves are not suitable for high temperature applications, as elastomeric O-rings tend to degrade or melt, leading to potential engine damage and safety risks during runaway conditions in diesel engines.
Innovation Solution
A disc assembly with a spring energized PTFE seal and a specially constructed design where the front and rear disc components are permanently secured with a recess and confronting surface to form an annular groove, capturing the seal and preventing separation at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastomeric O-ring is used in a conventional single-component disc assembly, then the valve can be manufactured with simple structure and low cost, but the seal degrades or melts at high temperatures causing component separation and potential engine damage
Solution Approach 1:
The disc assembly is divided into multiple components: a front disc component, a rear disc component, and a seal component. This segmentation allows each component to be optimized for its specific function, with the seal being replaceable and the disc components being permanently secured together, resolving the contradiction between reliability and complexity by making the system modular while maintaining structural integrity
Solution Approach 2:
The invention uses a composite seal assembly combining a PTFE seal with a spring mechanism, and permanently secures the front and rear disc components together. This composite structure provides both the sealing function and the structural stability needed for high-temperature applications, eliminating the single-material limitations of conventional O-rings
2Reliability
If a spring energized PTFE seal with permanently secured disc components is used, then high-temperature resistance and seal reliability are improved, but the manufacturing process becomes more complex requiring precise alignment of recess and confronting surface
Solution Approach 1:
The rear disc component is pre-formed with a recess that will receive the seal, and the front disc component is pre-formed with a confronting surface. These preliminary structural preparations ensure that when the components are assembled and permanently secured, the seal is automatically captured in the correct position without requiring complex alignment procedures during final assembly
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 solution provides a reliable, high-temperature-resistant seal that maintains integrity during engine operation, preventing component separation and ensuring safe engine shutdown even in extreme temperature conditions.
Implementation Method 1
a spring energized PTFE seal
Implementation Method 2
spring energized
Implementation Method 3
PTFE seal
Implementation Method 4
permanently secured, e.g., welded
Data Source
AI summary
A shutoff valve, e.g., an engine shutoff valve, is provided which includes a valve body having a fluid, e.g., air, passage and a disc assembly. The disc assembly is pivotable within the fluid passage from an open position to provide for free flow of fluid through the passage, to a closed position to provide a substantially closed off the fluid passage. The disc assembly includes a front disc, a rear disc, and a seal, e.g., a spring energized PTFE seal, disposed between the front disc and the rear disc. The front disc is permanently secured, e.g., welded, soldered or brazed, to the rear disc such that the seal is captured between the front disc and the rear disc.