Thermal Bypass Valve for Heat Exchangers With Leak-Resistant Actuation
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Solution Overview
Problem
Current aviation bypass valves in air-cooled oil cooler systems are unreliable due to sealing issues and complex, costly designs, particularly those using dual springs and phase-changing wax, which lead to increased weight and manufacturing defects.
Innovation Solution
A simplified design featuring thermally sensing multi-metallic plates or shape memory alloy actuation components, such as bi-metal or AlSiC-based plates, that provide both thermal activation and pressure relief without the need for external energy or wax, utilizing ultrasonic additive manufacturing for low-mass, high-strength construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure-actuated valves or dual spring thermal valves are used, then bypass function is provided, but reliability deteriorates due to sealing issues and wax leakage
Solution Approach 1:
The patent removes the wax actuator and dual spring mechanism from the valve assembly, retaining only the essential bypass valve body and seal components. This extraction of problematic elements eliminates the sources of leakage and sealing failures while preserving the core bypass functionality.
Solution Approach 2:
The simplified valve design relies on the natural pressure differential across the valve to control bypass flow, eliminating the need for external thermal actuators and complex spring mechanisms. The valve self-regulates based on system pressure conditions, improving reliability without additional moving parts.
2Weight of moving object
If dual springs and wax thermal actuators are included, then thermal activation is achieved, but weight increases
Solution Approach 1:
The patent replaces the mechanical wax actuator and spring system with a pressure-differential-based control mechanism. This substitution eliminates the need for thermal expansion materials and mechanical springs, significantly reducing valve weight while maintaining thermal response capability through pressure-driven flow control.
3Manufacturing precision
If complex valve assemblies with multiple components are used, then sealing is attempted, but manufacturing defects increase
Solution Approach 1:
The patent divides the valve system into minimal essential segments: a valve body, a seal element, and flow passages. By segmenting only the necessary components and eliminating redundant parts, the design reduces assembly complexity and manufacturing defects while maintaining adequate sealing through focused attention on the essential seal interface.
4Temperature
If bypass valve allows oil to bypass cooler, then thermal management is improved, but hydraulic loss occurs
Solution Approach 1:
The patent implements a dynamic bypass valve that automatically adjusts flow based on real-time pressure differential conditions. The valve opens or closes depending on whether the pressure differential across the cooler is sufficient, optimizing thermal management while minimizing unnecessary bypass flow that would cause hydraulic loss. This dynamic control ensures bypass occurs only when thermally beneficial.
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 reduces defects, rework, and overall cost while enhancing thermal response and reliability, minimizing hydraulic loss and fuel consumption with a low-profile, low-mass design that is less prone to leakage and assembly errors.
Implementation Method 1
thermally sensing multi-metallic plates that provide both thermal activation and pressure relief
Implementation Method 2
shape memory alloy actuation components, such as bi-metal or AlSiC-based plates
Data Source
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AI summary
A valve 110 and a heat exchanger apparatus 50 for a gas turbine engine 10 include a valve body 110 having a valve seat 124 and an actuation component 116 including a plate 118 formed from a set of metal layers and responsive to a change in at least one of a thermal condition and a pressure exerted thereon such that the plate 118 moves and the valve 110 moves between an opened and a closed position where a portion of the plate 118 engages with the valve seat 124.