Liquefied Hydrogen Valve Testing Below 20K Using Helium Gas
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for testing liquefied hydrogen valves under cryogenic conditions face challenges due to the high cost and scarcity of liquid helium, and the hazards associated with using liquefied hydrogen, making it difficult to perform safe and convenient leakage and performance tests.
Innovation Solution
An apparatus using low-cost helium gas and a cryogenic refrigerator with a heat conductor to create cryogenic conditions below 20K, employing a double-vessel structure with multi-layer insulation and a heat conductor to cool the valve body, allowing for safe and efficient testing without liquefied hydrogen or liquid helium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid helium is used to create cryogenic conditions below 20K, then the testing temperature requirement is met, but the cost and availability become problematic
Solution Approach 1:
The patent uses liquid nitrogen as an intermediary cooling medium instead of directly using liquid helium. The test valve is immersed in liquid nitrogen (boiling point 77K), and a cryogenic refrigerator with a cold head is used to achieve the required below-20K temperatures. This intermediary approach makes the testing system more accessible and cost-effective while still achieving the necessary cryogenic conditions.
Solution Approach 2:
The patent creates a simulated cryogenic environment using liquid nitrogen and a cryogenic refrigerator system that replicates the conditions of direct liquid helium cooling. The double-vessel structure with vacuum insulation copies the thermal isolation properties of direct helium immersion, allowing testing without the expensive and scarce liquid helium.
2Reliability
If liquefied hydrogen is used for testing, then the actual service conditions are replicated, but safety hazards increase due to explosiveness
Solution Approach 1:
The patent uses inert gases (liquid nitrogen for cooling, helium gas for flow testing) as intermediaries to simulate the physical and thermal behavior of liquefied hydrogen without using the hazardous hydrogen itself. These intermediaries replicate the cryogenic temperature effects and flow characteristics while eliminating the explosive risks associated with actual hydrogen.
Solution Approach 2:
The patent creates an inert testing environment using liquid nitrogen and helium gas, which are non-flammable and safe to handle. This inert atmosphere replaces the hazardous hydrogen environment while still allowing realistic testing of valve performance under cryogenic conditions, thus eliminating safety hazards while maintaining test validity.
3Device complexity
If a simple single-vessel structure is used, then device complexity is reduced, but thermal insulation performance deteriorates
Solution Approach 1:
The patent employs a double-vessel nested structure where an inner vessel containing the test valve is placed inside an outer vessel. The annular space between the vessels is evacuated to create a vacuum layer, providing superior thermal insulation. This nested configuration maintains excellent thermal isolation performance while organizing the complexity into a manageable, modular design.
Solution Approach 2:
The patent uses thin-walled vessels with vacuum insulation and multi-layer reflective barriers to achieve high thermal performance. The thin film structures and vacuum space provide exceptional insulation without adding significant bulk or complexity, allowing the system to maintain below-20K temperatures efficiently.
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
Enables safe and cost-effective leakage and performance testing of liquefied hydrogen valves by simulating cryogenic conditions using helium gas, overcoming the limitations of existing methods.
Implementation Method 1
a heat conductor, one end of which is coupled to the cold head part of the cryogenic refrigerator and the other end of which is coupled to the valve body of the test valve, and which cools the valve body of the test valve to a temperature below 20K
Implementation Method 2
a test vessel in which a valve body of a test valve is inserted into a vacuum-exhausted inside
Implementation Method 3
a double-vessel structure with multi-layer insulation
Data Source
AI summary
Disclosed herein is an apparatus for testing liquefied hydrogen valve that can configure the test valve to environmental conditions of a temperature below 20K by using only low-cost helium gas without using liquefied hydrogen or liquid helium as the test fluid. This helps companies developing liquefied hydrogen valves to safely and conveniently perform valve leakage and performance tests. In accordance with the present invention, the apparatus for testing liquefied hydrogen valve includes a test vessel in which a valve body of a test valve is inserted into a vacuum-exhausted inside and sealed with a vessel cover so that an operating part of the test valve protrudes to an outside; an inlet pipe, one end of which is connected to an inlet port of the valve body; an outlet pipe, one end of which is connected to an outlet port of the valve body; a helium tank connected to the other end of the inlet pipe to supply helium gas to the inlet port of the valve body; a cryogenic refrigerator in which a cold head part that cools to a temperature below 20K is inserted into the test vessel, and a gas compression part that suctions, compresses and discharges a refrigerant gas is sealed so that it protrudes out of the vessel cover; a heat conductor, one end of which is coupled to the cold head part of the cryogenic refrigerator and the other end of which is coupled to the valve body of the test valve, and which cools the valve body of the test valve to a temperature below 20K; and a pressure sensor and a flow sensor installed on the inlet pipe and the outlet pipe to measure pressure and flow rate, respectively.