Fuel Cell Recirculation Blocking Valve Using Hydrogen Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing blocking devices for fuel cell recirculation loops are expensive due to the need for large, low-resistance valves to manage hydrogen recirculation and gas venting, especially when operating conditions require preventing recirculation and venting of nitrogen and other undesirable gases.
Innovation Solution
A blocking device utilizing high hydrogen pressure from a reservoir to actuate a recirculation loop blocking valve, with a smaller hydrogen switching valve controlling the larger blocking valve, allowing the pressure energy to move the valve slide and prevent recirculation, while maintaining fresh hydrogen supply and using static seals to reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large, low-resistance blocking valve is used to prevent recirculation loop operation, then recirculation can be effectively blocked, but the device becomes expensive
Solution Approach 1:
The blocking device is divided into two separate valves: a first valve (recirculation loop blocking valve) with a relatively small cross-section for blocking, and a second valve (flow control valve) with a larger cross-section for maintaining flow. This segmentation allows each valve to be optimized for its specific function, reducing the overall cost while maintaining reliability.
Solution Approach 2:
A T-piece is introduced as an intermediary component that connects the recirculation loop, the first valve, the second valve, and the hydrogen reservoir. This allows the high-pressure hydrogen from the reservoir to act on the larger cross-section valve, enabling it to overcome the spring force and maintain system flow while the smaller first valve provides effective blocking when needed.
2Productivity
If the recirculation loop blocking valve has a large cross-section to maintain flow, then flow restriction is minimized, but the valve becomes expensive
Solution Approach 1:
The flow control function is separated from the blocking function. The second valve (flow control valve) handles the large cross-section flow requirements, while the first valve (recirculation loop blocking valve) handles the blocking function with a smaller, more cost-effective cross-section.
Solution Approach 2:
The system uses pneumatic pressure from the high-pressure hydrogen reservoir to act on the larger cross-section valve. The pressure force generated by the high-pressure hydrogen (approximately 900 bar) acts on the T-piece to open the second valve, allowing large cross-section flow capacity without requiring an expensive large blocking valve.
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 cost-effective and reliable blocking mechanism that effectively prevents recirculation loop operation without restricting flow, allowing for continuous hydrogen supply and efficient gas management, using existing pressure energy and static seals to minimize expenses.
Implementation Method 1
the recirculation loop blocking valve is controlled by high hydrogen pressure in a reservoir (currently approx. 900 bar), wherein the hydrogen supply pressure then actuates a valve slide of the recirculation loop blocking valve
Data Source
AI summary
A blocking device for a recirculation loop in a fuel cell stack comprises a hydrogen inlet and a recirculation gas inlet. In order to obtain an inexpensive blocking device for the recirculation loop, a recirculation loop blocking valve is provided, which is switched by an upstream hydrogen switching valve.