Nested Piston Valve Assembly for Linear High-Flow Anti-Ice Control
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Solution Overview
Problem
Existing anti-ice system valves for aircraft struggle to balance high mass flow rates and linear pressure regulation, with butterfly valves excelling at low mass flows but lacking linearity and high-flow capabilities, while other valves are better at high mass flows but less effective at lower ranges.
Innovation Solution
A valve assembly featuring a dual co-axial piston configuration with overlapping pistons, where the first piston and regulating piston have increased stroke lengths without increasing the overall valve length, allowing for enhanced airflow and linear pressure regulation by eliminating the need for a nose portion and associated chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a butterfly valve is used, then high mass flow rate is achieved at low mass-flow ranges, but linearity of pressure regulation is poor
Solution Approach 1:
The valve is segmented into two independent pistons: a first piston for shut-off function and a regulating piston for pressure regulation. This segmentation allows each piston to be optimized for its specific function, with the regulating piston providing linear pressure regulation independent of the shut-off piston's position.
Solution Approach 2:
The regulating piston is nested within the first piston, with the regulating piston having a smaller diameter and being positioned inside the larger first piston. This nested arrangement allows both pistons to occupy the same longitudinal space, increasing stroke lengths without increasing overall valve length, while maintaining both high flow capacity and linear regulation.
2Manufacturing precision
If a traditional piston-based valve is used, then linear pressure regulation is achieved, but maximum mass flow rate is reduced
Solution Approach 1:
The regulating piston is nested within the first piston, allowing the fluid passage to flow around the outer periphery of the first piston and through the interior of the regulating piston. This creates multiple parallel flow paths that maintain high mass flow capacity while the regulating piston provides precise linear pressure regulation.
Solution Approach 2:
The fluid passage is configured to flow in multiple dimensions: around the outer periphery of the first piston and through the interior of the nested regulating piston. This multi-dimensional flow arrangement increases the effective flow area without increasing the valve's external dimensions, maintaining high mass flow rate while enabling linear regulation.
3Productivity
If piston stroke length is increased to improve airflow, then valve length must be increased
Solution Approach 1:
The regulating piston is nested within the first piston, both moving coaxially along the same longitudinal axis. This allows both pistons to have increased stroke lengths independently without increasing the overall valve length, as their movements occur within the same spatial envelope. The nested arrangement effectively doubles the available stroke length within the same valve body.
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 valve assembly achieves increased maximum airflow and improved linearity across various mass flow rates, surpassing the limitations of both butterfly and traditional piston-based valves by allowing greater fluid flow without the restrictions of prior designs.
Implementation Method 1
the regulating piston will be moved depending on a pressure difference between downstream pressure and pressure in a regulating chamber 14a, which in turn will change the amount of mass flow through the valve assembly 10
Implementation Method 2
the first piston overlaps the regulating piston when the first piston is its first position and the regulating piston is in its second position
Data Source
AI summary
A valve assembly for an anti-ice system of an aircraft. The valve assembly comprises: a valve body; a first piston; and a regulating piston. The valve body defines a valve inlet, a valve outlet, a fluid passage between the valve inlet and the valve outlet, and a core portion defining a first chamber by cooperation with the first piston and a regulating chamber by cooperation with the regulating piston. The first piston is moveable between a first position and a second position, and the regulating piston is movable between a first position and a second position. The first piston overlaps the regulating piston when the first piston is its first position and the regulating piston is in its second position.