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Sealing Hydrogen in an Aerospace Refueling Station
A customer approached the Engineered Polymer Systems (EPS) Division in search of a sealing system that would effectively seal hydrogen in a unique storage container used for an aerospace refueling station. The cylinder featured a 12-inch diameter bore operated by pressurized water for hydrogen gas storage. This method of pressurization is distinct from traditional systems that often rely on oil, which is too flammable to safely use in a fuel system.
The Challenge: Sealing Hydrogen
The primary challenge in this application was sealing hydrogen effectively. Hydrogen molecules are incredibly small, making it notoriously difficult to contain without leakage. Given the hydrogen industry's stringent leakage requirements, the need for a reliable sealing solution was paramount. The combination of flammable, high-pressure hydrogen and water (which is a poor lubricator) created a demanding environment for seals, necessitating materials that could withstand these conditions while maintaining an effective seal.
Our Sealing Solution: Ultra-High Molecular Weight Polyethylene and Nitrile Rubber
We developed a sealing system using a combination of Parker’s ultra-high molecular weight (UHMW) FlexiSeals and bi-directional rubber seals. Our UHMW material is known for its low friction, long wear resistance, and compatibility with water. Our rubber seals are particularly effective at containing light gases like hydrogen. These seal designs also incorporated hard plastic backups in order to handle the high system pressure. This combination of materials and design allowed us to create a reliable sealing solution that met the demanding requirements of both water and hydrogen applications, ensuring optimal performance in an extraordinary setting.
