Passive Flow Limiting Valve for High-Pressure Gas Surges
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Solution Overview
Problem
High pressure gas applications, such as hydrogen fueling systems, experience frequent and substantial deviations in mass flow rate due to rapid changes in pressure and transient conditions, leading to inefficient control of flow rates.
Innovation Solution
A fast-responding passive flow rate limiting valve that integrates with a downstream control valve, featuring a poppet mechanism that adjusts flow resistance based on differential pressure, ensuring rapid control responses and maintaining flow rates within specified limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a fast-acting control valve is used to respond to transient pressure changes, then the control response speed is improved, but substantial and frequent deviations in mass flow rate occur due to the highly transient state of the system
Solution Approach 1:
The flow control system is segmented into two independent valves: a primary fast-acting control valve for rapid response to pressure transients, and a secondary flow rate limiting valve to constrain maximum flow rate. This segmentation allows each valve to specialize in one function, resolving the contradiction between fast response and flow stability.
Solution Approach 2:
The flow rate limiting valve acts as an intermediary element between the pressure source and the control valve. It mediates the interaction by limiting the maximum flow rate that can pass through the system, preventing excessive flow deviations even when the control valve responds rapidly to pressure changes.
2Measurement precision
If the flow control valve cycles frequently to maintain flow rate during tank switching, then the flow rate control accuracy is improved, but the valve wear and system complexity increase
Solution Approach 1:
The flow rate limiting valve is designed as a passive device that automatically limits flow rate based on the pressure differential across it, without requiring active control or cycling. This self-service mechanism reduces the complexity of valve control during tank switching events while maintaining flow rate accuracy.
3Reliability
If a passive flow rate limiting valve is added to the system, then the flow rate stability is improved, but the device complexity increases
Solution Approach 1:
The flow rate limiting function is extracted as a separate, dedicated valve rather than being integrated into the existing control valve. This extraction allows the limiting function to operate independently and passively, improving flow rate stability without requiring complex control logic or modifying the existing control valve.
Solution Approach 2:
The flow rate limiting valve is designed as a simple, robust device with no moving parts or electronic components that would fail. It uses a basic spring-loaded poppet mechanism that is inherently reliable and maintenance-free, providing stable flow rate limiting without adding significant complexity or reliability concerns.
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 passive flow rate limiting valve effectively stabilizes flow rates by increasing resistance during high differential pressure conditions and reopening to allow the active control valve to regain control when pressure drops, thereby reducing flow rate deviations.
Implementation Method 1
a spring positioned downstream of the poppet and configured to bias the poppet toward the open position
Implementation Method 2
limiting the mass flow rate of gas from a high pressure to a low pressure region
Data Source
AI summary
A fast-responding passive flow rate limiting valve for high pressure gas applications, the valve comprising a valve body having a flow passageway extending from an upstream end to a downstream end of the valve body. The flow passageway includes a first bore portion in the upstream end of the valve body in fluid communication with one or more ports spaced around an inner passageway in the upstream end of the valve body. The inner passageway and one or more ports extend to a body elongate bore which extends to the downstream end of the valve body. A poppet extends into and through the inner passageway and includes an inner bore having a plurality of poppet ports. In a poppet open position the poppet ports are unobstructed and open to the first bore portion and in a poppet closed position the poppet ports are within the inner passageway and at least partially obstructed. A spring, received within the body elongate bore, provides a spring force on the poppet in an upstream direction. The valve rapidly transitions from the open position to the closed position upon an upstream fluid pressure spike acting on the poppet causing a restriction to fluid flow and quickly limiting the flow rate through the valve.